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Sample records for oxide fiber targets

  1. Quasar target selection fiber efficiency

    SciTech Connect

    Newberg, H.; Yanny, B.

    1996-05-01

    We present estimates of the efficiency for finding QSOs as a function of limiting magnitude and galactic latitude. From these estimates, we have formulated a target selection strategy that should net 80,000 QSOs in the north galactic cap with an average of 70 fibers per plate, not including fibers reserved for high-redshift quasars. With this plan, we expect 54% of the targets to be QSOs. The North Galactic Cap is divided into two zones of high and low stellar density. We use about five times as many fibers for QSO candidates in the half of the survey with the lower stellar density as we use in the half with higher stellar density. The current plan assigns 15% of the fibers to FIRST radio sources; if these are not available, those fibers would be allocated to lower probability QSO sources, dropping the total number of QSOs by a small factor (5%). We will find about 17,000 additional quasars in the southern strips, and maybe a few more at very high redshift. Use was made of two data sets: the star and quasar simulated test data generated by Don Schneider, and the data from UJFN plate surveys by Koo (1986) and Kron (1980). This data was compared to results from the Palomar-Green Survey and a recent survey by Pat Osmer and collaborators.

  2. Ceramic oxide fibers

    SciTech Connect

    Sowman, H.G.; Johnson, D.D.

    1985-10-01

    Polycrystalline ceramic fibers now available from commercial sources include those of Al/sub 2/O/sub 3/, Al/sub 2/O/sub 3/-SiO/sub 2/O/sub 3/, Al/sub 2/O/sub 3/-B/sub 2/O/sub 3/-SiO/sub 2/, and ZrO/sub 2/-SiO/sub 2/. Continuous filaments in roving, yarn, chopped, bulk, fabric or mat forms can be supplied. Properties and uses of these fibers are discussed. 18 references.

  3. Fiber optic applications for laser polarized targets

    SciTech Connect

    Cummings, W.J.; Kowalczyk, R.S.

    1997-10-01

    For the past two years, the laser polarized target group at Argonne has been used multi-mode fiber optic patch cords for a variety of applications. In this paper, the authors describe the design for transporting high power laser beams with optical fibers currently in use at IUCF.

  4. Polyacrylonitrile fibers containing graphene oxide nanoribbons.

    PubMed

    Chien, An-Ting; Liu, H Clive; Newcomb, Bradley A; Xiang, Changsheng; Tour, James M; Kumar, Satish

    2015-03-11

    Graphene oxide nanoribbon (GONR) made by the oxidative unzipping of multiwalled carbon nanotube was dispersed in dimethylformamide and mixed with polyacrylonitrile (PAN) to fabricate continuous PAN/GONR composite fibers by gel spinning. Subsequently, PAN/GONR composite fibers were stabilized and carbonized in a batch process to fabricate composite carbon fibers. Structure, processing, and properties of the composite precursor and carbon fibers have been studied. This study shows that GONR can be used to make porous precursor and carbon fibers. In addition, GONR also shows the potential to make higher mechanical property carbon fibers than that achieved from PAN precursor only. PMID:25671488

  5. BN Bonded BN fiber article from boric oxide fiber

    DOEpatents

    Hamilton, Robert S.

    1978-12-19

    A boron nitride bonded boron nitride fiber article and the method for its manufacture which comprises forming a shaped article with a composition comprising boron oxide fibers and boric acid, heating the composition in an anhydrous gas to a temperature above the melting point of the boric acid and nitriding the resulting article in ammonia gas.

  6. Conditional knockout of Mn-SOD targeted to type IIB skeletal muscle fibers increases oxidative stress and is sufficient to alter aerobic exercise capacity

    PubMed Central

    Lustgarten, Michael S.; Jang, Youngmok C.; Liu, Yuhong; Muller, Florian L.; Qi, Wenbo; Steinhelper, Mark; Brooks, Susan V.; Larkin, Lisa; Shimizu, Takahiko; Shirasawa, Takuji; McManus, Linda M.; Bhattacharya, Arunabh; Richardson, Arlan

    2009-01-01

    In vitro studies of isolated skeletal muscle have shown that oxidative stress is limiting with respect to contractile function. Mitochondria are a potential source of muscle function-limiting oxidants. To test the hypothesis that skeletal muscle-specific mitochondrial oxidative stress is sufficient to limit muscle function, we bred mice expressing Cre recombinase driven by the promoter for the inhibitory subunit of troponin (TnIFast-iCre) with mice containing a floxed Sod2 (Sod2fl/fl) allele. Mn-SOD activity was reduced by 82% in glycolytic (mainly type II) muscle fiber homogenates from young TnIFastCreSod2fl/fl mice. Furthermore, Mn-SOD content was reduced by 70% only in type IIB muscle fibers. Aconitase activity was decreased by 56%, which suggests an increase in mitochondrial matrix superoxide. Mitochondrial superoxide release was elevated more than twofold by mitochondria isolated from glycolytic skeletal muscle in TnIFastCreSod2fl/fl mice. In contrast, the rate of mitochondrial H2O2 production was reduced by 33%, and only during respiration with complex II substrate. F2-isoprostanes were increased by 36% in tibialis anterior muscles isolated from TnIFastCreSod2fl/fl mice. Elevated glycolytic muscle-specific mitochondrial oxidative stress and damage in TnIFastCreSod2fl/fl mice were associated with a decreased ability of the extensor digitorum longus and gastrocnemius muscles to produce contractile force as a function of time, whereas force production by the soleus muscle was unaffected. TnIFastCreSod2fl/fl mice ran 55% less distance on a treadmill than wild-type mice. Collectively, these data suggest that elevated mitochondrial oxidative stress and damage in glycolytic muscle fibers are sufficient to reduce contractile muscle function and aerobic exercise capacity. PMID:19776389

  7. Indium oxide based fiber optic SPR sensor

    NASA Astrophysics Data System (ADS)

    Shukla, Sarika; Sharma, Navneet K.

    2016-05-01

    Surface plasmon resonance based fiber optic sensor using indium oxide layer is presented and theoretically studied. It has been found that with increase in thickness of indium oxide layer beyond 170 nm, the sensitivity of SPR sensor decreases. 170 nm thick indium oxide layer based SPR sensor holds maximum sensitivity.

  8. Genotoxic mechanisms of asbestos fibers: role of extranuclear targets.

    PubMed

    Xu, An; Huang, Xuelian; Lien, Yu-Chin; Bao, Lingzhi; Yu, Zengliang; Hei, Tom K

    2007-05-01

    Asbestos fibers are carcinogenic to both humans and experimental animals. The continued discoveries of exposure routes whereby the general public is exposed to asbestos suggest a long-term, low-dose exposure for a large number of people. However, the mechanisms by which asbestos induces malignancy are not entirely understood. In previous studies, we have shown that asbestos is an effective gene and chromosomal mutagen when assayed using the highly sensitive AL mutation assay and that the mutagenicity is mediated by reactive oxygen species. The objective of the present study is to determine the origin of these radical species, particularly reactive nitrogen species, in fiber mutagenesis. Using the radical probe 5',6'-chloromethyl-2',7'-dihydroxyphenoxazine diacetate to trap reactive radical species, we showed that crocidolite increased the levels of oxyradicals in cytoplasts, in the absence of the nucleus, in a dose-dependent manner, which was reduced significantly by cotreatment with the radical scavenger dimethyl sulfoxide. Treatment of enucleated cells with crocidolite asbestos followed by rescue fusion using karyoplasts from control cells resulted in significant mutant induction, indicating that the nuclear-cytoplasmic interaction is necessary for fiber mutagenesis. Using the fluorescent probe 2,3-diaminonaphthotriazole, crocidolite fibers were shown to induce a dose-dependent increase of nitric oxide production, which was suppressed significantly by concurrent treatment with the nitric oxide synthase inhibitor, NG-methyl-L-arginine (L-NMMA). Similarly, there was a dose-dependent decrease in the mutation yield induced by crocidolites in the presence of graded doses of L-NMMA. These data showed that extranuclear targets play an essential role in the initiation of oxidative damage that mediates fiber mutagenesis in mammalian cells. PMID:17447795

  9. Oxidation induced stress-rupture of fiber bundles

    SciTech Connect

    Lara-Curzio, E.

    1997-03-01

    The effect of oxidation on the stress-rupture behavior of fiber bundles was modeled. It is shown that oxidation-induced fiber strength degradation results in the delayed failure of the associated fiber bundle and that the fiber bundle strength decreases with time as t{sup {minus}1/4}. It is also shown that the temperature dependence of the bundle loss of strength reflects the thermal dependence of the mechanism controlling the oxidation of the fibers. The effect of gauge length on the fiber bundle strength was also analyzed. Numerical examples are presented for the special case of Nicalon{trademark} fibers.

  10. Strong, damage tolerant oxide-fiber/oxide matrix composites

    NASA Astrophysics Data System (ADS)

    Bao, Yahua

    Electrophoretic deposition (EPD) is an easy and cost effective method to fabricate fiber-reinforced green composites. Non-conductive Nextel(TM) 720 fibers were successfully coated with a transient, conductive polypyrrole submicron surface layer for use directly as an electrode in EPD processing. However, electric-field shielding limits particle infiltration into the conductive fiber bundles and they mostly deposit on the outer surface of the fiber bundle. When the bundle is large, central cavities exist after deposition. The EPD cell was modified for electrophoretic infiltration deposition (EPID). Non conductive fibers were laid on an electrode and charged particles in an ethanol suspension are driven there through by an electric field, infiltrate and deposit on the electrode to then build up into the fiber preform and fill the voids therein. Dense, uniform, green fiber composites were successfully fabricated via constant current EPID. The EPID process is modeled as capillary electrophoretic infiltration. The process consists of two steps: particle electrophoresis outside the capillaries and electrophoretic infiltration inside the capillaries. Due to the zero net flow of the ethanol across the capillary cross-section, there is no electro-osmotic flow contribution to the deposition rate. Hamaker's law was extended to the EPID process, i.e., the deposition yield is proportional to the electric field inside the capillaries. The total deposition yield is controlled by the slow step of the process, i.e., the rate of electrophoresis in the open suspension outside the capillaries. AlPO4 was proposed as a weak layer between oxide fibers and oxide matrix in fiber-reinforced ceramic matrix composites (CMC's). AlPO 4 nano particles were synthesized by chemical co-precipitation of Al 3+ and HPO42- with urea at 95°C. The solution pH basic region and amorphous AlPO4 precipitated of narrow size distribution with a mean particle size 50nm. Nextel 720 fibers were pretreated with

  11. Creep rupture of an oxide/oxide composite fiber

    NASA Astrophysics Data System (ADS)

    Hammond, Vincent Harold

    Due to their low-cost and thermal stability, alumina-based tow-fibers are currently being considered for use in elevated temperature composites. Unfortunately, the fine grain size of the filaments results in extremely poor creep resistance when subjected to high temperature loading. The recent development of a tow-based composite fiber offers a possible solution for improving the creep performance of these materials. To explore the viability of this approach, the creep response of an oxide/oxide composite fiber has been determined through a series of uniaxial creep tests. Despite the high porosity content of the alumina matrix, significant improvements in both steady-state creep rate and creep lifetimes were observed for the composite fibers relative to the as-received tows. The creep strength was found to be strongly sensitive to sintering temperature but only mildly dependent on matrix volume fraction within the range studied. A transition from tough to brittle fracture was also observed in the composite fiber with increasing sintering temperature. An analytical model was developed for predicting the creep response of the as-received Nextel 610 tow. The strain-time history of the tow is generated using the power-law creep rate equation for a Nextel 610 single filament. The failure strain of the tow is predicted using a damage mechanics approach based on a Monkman-Grant type parameter. Predicted values of creep lifetime and failure strain are within 20% of those measured experimentally. The model is then extended to address the creep response of the composite fiber by incorporating the influence of composite fiber architecture, interfacial roughness, and clamping stresses on the reloading of failed filaments.

  12. Fiber optic moisture sensor with moisture-absorbing reflective target

    DOEpatents

    Kirkham, Randy R.

    1987-01-01

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  13. The high temperature creep behavior of oxides and oxide fibers

    NASA Technical Reports Server (NTRS)

    Jones, Linda E.; Tressler, Richard E.

    1991-01-01

    A thorough review of the literature was conducted on the high-temperature creep behavior of single and polycrystalline oxides which potentially could serve as fiber reinforcements in ceramics or metal matrix applications. Sapphire when oriented with the basal plane perpendicular to the fiber axis (c-axis oriented) is highly creep resistant at temperatures in excess of 1600 C and applied loads of 100 MPa and higher. Pyramidal slip is preferentially activated in sapphire under these conditions and steady-state creep rates in the range of 10(exp -7) to 10 (exp -8)/s were reported. Data on the creep resistance of polycrystalline beryllia suggest that C-axiz oriented single crystal beryllia may be a viable candidate as a fiber reinforcement material; however, the issure of fabricability and moisture sensitivity must be addressed for this material. Yttrium aluminum garnet (YAG) also appears to be a fiber candidate material having a high resistance to creep which is due to it's complex crystal structure and high Peierl resistance. The high creep resistance of garnet suggests that there may be other complex ternary oxides such as single crystal mullite which may also be candidate materials for fiber reinforcements. Finally, CVD and single crystal SiC, although not oxides, do possess a high resistance to creep in the temperature range between 1550 and 1850 C and under stresses of 110 to 220 MPa. From a review of the literature, it appears that for high creep resistant applications sapphire, silicon carbide, yttrium aluminum garnet, mullite, and beryllia are desirable candidate materials which require further investigation.

  14. Characterization and Oxidation Behavior of Rayon-Derived Carbon Fibers

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan; Hull, David

    2010-01-01

    Rayon-derived fibers are the central constituent of reinforced carbon/ carbon (RCC) composites. Optical, scanning electron, and transmission electron microscopy were used to characterize the as-fabricated fibers and the fibers after oxidation. Oxidation rates were measured with weight loss techniques in air and oxygen. The as-received fibers are approximately 10 micron in diameter and characterized by grooves or crenulations around the edges. Below 800 C, in the reaction-controlled region, preferential attack began in the crenulations and appeared to occur down fissures in the fibers.

  15. Synthesis of Titanium Oxide Nanoparticles by Ytterbium Fiber Laser Ablation

    NASA Astrophysics Data System (ADS)

    Boutinguiza, M.; del Val, J.; Riveiro, A.; Lusquiños, F.; Quintero, F.; Comesaña, R.; Pou, J.

    Nanosized titanium particles have recently received a special attention due to their applications in many different fields, such as catalysis, biomedical engineering, etc. Pulsed laser ablation in liquid media allows obtaining metallic and metallic oxide nanoparticles in colloids. This technique has been used in the present work to prepare titanium colloids from a solid piece immersed in liquid media. A monomode Ytterbium doped fiber laser has been focused onto the upper surface of the titanium target in de-ionized water or ethanol. Crystalline phases, morphology and optical properties of the obtained colloidal nanoparticles were characterized by XRD, HRTEM, and UV/VIS absorption spectroscopy. The produced titanium oxide crystalline nanoparticles show spherical shape and are polycrystalline, exhibiting anatase as well as rutile phases.

  16. Recent developments in polycrystalline oxide fiber laser materials: production of Yb-doped polycrystalline YAG fiber

    NASA Astrophysics Data System (ADS)

    Lee, HeeDong; Keller, Kristin; Sirn, Brian; Parthasarathy, Triplicane; Cheng, Michael; Hopkins, Frank K.

    2011-09-01

    Laser quality, polycrystalline oxide fibers offer significant advantages over state-of-the-art silica fiber for high energy lasers. Advanced ceramic processing technology, along with a novel powder production process, has potential to produce oxide fibers with an outstanding optical quality for use in the fiber laser applications. The production of contaminant-free green fibers with a high packing density, as well as uniform packing distribution, is a key factor in obtaining laserquality fibers. High quality green fibers are dependent on the powder quality combined with the appropriate slurry formulation. These two fundamental technologies were successfully developed at UES, and used to produce Yb-doped yttrium aluminum garnet (YAG) fibers with high optical quality, high chemical purity, and suitable core diameters down to 20-30 microns.

  17. A comparison of fiber effects on polymer matrix composite oxidation

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    1991-01-01

    A number of thermo-oxidative stability studies addressing the effects of fiber reinforcement on composite thermal stability and influence of geometry on the results of aging studies were performed at NASA-Lewis. The information presented herein, a compilation of some results from these studies, shows the influence of the reinforcement fibers on the oxidative degradation of various PMR-15 composites. Reinforcement of graphite and ceramics were studied and three composite oxidation mechanisms were observed. One was a dominant attack of the reinforcement fiber, the second was the aggressive oxidation of the matrix material, and the third was interfacial degradation.

  18. The muscle fiber type–fiber size paradox: hypertrophy or oxidative metabolism?

    PubMed Central

    van Wessel, T.; de Haan, A.; van der Laarse, W. J.

    2010-01-01

    An inverse relationship exists between striated muscle fiber size and its oxidative capacity. This relationship implies that muscle fibers, which are triggered to simultaneously increase their mass/strength (hypertrophy) and fatigue resistance (oxidative capacity), increase these properties (strength or fatigue resistance) to a lesser extent compared to fibers increasing either of these alone. Muscle fiber size and oxidative capacity are determined by the balance between myofibrillar protein synthesis, mitochondrial biosynthesis and degradation. New experimental data and an inventory of critical stimuli and state of activation of the signaling pathways involved in regulating contractile and metabolic protein turnover reveal: (1) higher capacity for protein synthesis in high compared to low oxidative fibers; (2) competition between signaling pathways for synthesis of myofibrillar proteins and proteins associated with oxidative metabolism; i.e., increased mitochondrial biogenesis via AMP-activated protein kinase attenuates the rate of protein synthesis; (3) relatively higher expression levels of E3-ligases and proteasome-mediated protein degradation in high oxidative fibers. These observations could explain the fiber type–fiber size paradox that despite the high capacity for protein synthesis in high oxidative fibers, these fibers remain relatively small. However, it remains challenging to understand the mechanisms by which contractile activity, mechanical loading, cellular energy status and cellular oxygen tension affect regulation of fiber size. Therefore, one needs to know the relative contribution of the signaling pathways to protein turnover in high and low oxidative fibers. The outcome and ideas presented are relevant to optimizing treatment and training in the fields of sports, cardiology, oncology, pulmonology and rehabilitation medicine. Electronic supplementary material The online version of this article (doi:10.1007/s00421-010-1545-0) contains

  19. Crystal-free Formation of Non-Oxide Optical Fiber

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy A.

    2015-01-01

    Researchers at NASA Marshall Space Flight Center have devised a method for the creation of crystal-free nonoxide optical fiber preforms. Non-oxide fiber optics are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. However, some of these glasses are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. NASA has developed a new method of non-oxide fiber formation that uses axial magnetic fields to suppress crystallization. The resulting non-oxide fibers are crystal free and have lower signal attenuation rates than silica based optical fibers.

  20. Preparation of anti-oxidative carbon fiber at high temperature

    NASA Astrophysics Data System (ADS)

    Kim, Bo-Hye; Kim, Su Yeun; Kim, Chang Hyo; Yang, Kap Seung; Lee, Young-Jun

    2010-11-01

    In this paper, carbon fibers with improved thermal stability and oxidation resistive properties were prepared and evaluated their physical performances under oxidation condition. Carbon fibers were coated with SiC particles dispersed in a polyacrylonitrile solution and then followed by pyrolyzed at 1400 °C to obtain the SiC nanoparticle deposition on the surface of the carbon fiber. The SiC coated carbon fiber showed extended oxidation resistive property as remaining 80-88% of the original weight even at high temperature 1000 °C under air, as compared with the control of zero weight at 600 °C. The effects of the coating conditions on the oxidation resistive properties of the coated fibers were studied in detail.

  1. Oxidation of Carbon Fibers in Water Vapor Studied

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.

    2003-01-01

    T-300 carbon fibers (BP Amoco Chemicals, Greenville, SC) are a common reinforcement for silicon carbide composite materials, and carbon-fiber-reinforced silicon carbide composites (C/SiC) are proposed for use in space propulsion applications. It has been shown that the time to failure for C/SiC in stressed oxidation tests is directly correlated with the fiber oxidation rate (ref. 1). To date, most of the testing of these fibers and composites has been conducted in oxygen or air environments; however, many components for space propulsion, such as turbopumps, combustors, and thrusters, are expected to operate in hydrogen and water vapor (H2/H2O) environments with very low oxygen contents. The oxidation rate of carbon fibers in conditions representative of space propulsion environments is, therefore, critical for predicting component lifetimes for real applications. This report describes experimental results that demonstrate that, under some conditions, lower oxidation rates of carbon fibers are observed in water vapor and H2/H2O environments than are found in oxygen or air. At the NASA Glenn Research Center, the weight loss of the fibers was studied as a function of water pressure, temperature, and gas velocity. The rate of carbon fiber oxidation was determined, and the reaction mechanism was identified.

  2. Interactions between the glass fiber coating and oxidized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ku-Herrera, J. J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J. V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

    2015-03-01

    Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as "sizing"), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  3. Eliminating crystals in non-oxide optical fiber preforms and optical fibers

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R. (Inventor); Tucker, Dennis S. (Inventor)

    2010-01-01

    A method is provided for eliminating crystals in non-oxide optical fiber preforms as well as optical fibers drawn therefrom. The optical-fiber-drawing axis of the preform is aligned with the force of gravity. A magnetic field is applied to the preform as it is heated to at least a melting temperature thereof. The magnetic field is applied in a direction that is parallel to the preform's optical-fiber-drawing axis. The preform is then cooled to a temperature that is less than a glass transition temperature of the preform while the preform is maintained in the magnetic field. When the processed preform is to have an optical fiber drawn therefrom, the preform's optical-fiber-drawing axis is again aligned with the force of gravity and a magnetic field is again applied along the axis as the optical fiber is drawn from the preform.

  4. Oxidation-induced contraction and strengthening of boron fibers

    NASA Technical Reports Server (NTRS)

    Dicarlo, J. A.; Wagner, T. C.

    1981-01-01

    An investigation was conducted to measure and understand the physical and mechanical effects that occur in boron fibers during and after thermal treatment in a controlled oxygen argon gaseous mixture. Of principal concern was the optimization of this treatment as a secondary processing method for significantly improving fiber tensile strength. Strengthening was accomplished by an oxidation induced axial contraction of the fiber and a resulting axial compression of strength limiting flaws within the fiber's tungsten boride core. Various physical observations were used to develop mechanistic models for oxidation, contraction, and flow formation. Processing guidelines are discussed for possibly exceeding the 5.5 GN/sq m strength limit and also for achieving fiber strengthening during application of boron containing diffusion barrier coatings.

  5. Target allocation yields for massively multiplexed spectroscopic surveys with fibers

    SciTech Connect

    Saunders, Will; Smedley, Scott; Gillingham, Peter; Forero-Romero, Jaime E.; Jouvel, Stephanie; Nord, Brian

    2014-08-05

    We present Simulated Annealing fiber-to-target allocation simulations for the proposed DESI and 4MOST massively multiplexed spectroscopic surveys, and for both Poisson and realistically clustered mock target samples. We simulate both Echidna and theta-phi actuator designs, including the restrictions caused by the physical actuator characteristics during repositioning. For DESI, with theta-phi actuators, used in 5 passes over the sky for a mock ELG/LRG/QSO sample, with matched fiber and target densities, a total target allocation yield of 89.3% was achieved, but only 83.7% for the high-priority Ly-alpha QSOs. If Echidna actuators are used with the same pitch and number of passes, the yield increases by 5.7% and 16% respectively. Echidna also allows a factor-of-two increase in the number of close Ly-alpha QSO pairs that can be observed. Echidna spine tilt causes a variable loss of throughput, with average loss being the same as the loss at the rms tilt. With a natural tilt minimization scheme, we find an rms tilt always close to 0.58 x maximum. There is an additional but much smaller defocus loss, equivalent to an average defocus of 30microns. These tilt losses offset the gains in yield for Echidna, but because the survey strategy is driven by the higher priority targets, a clear survey speed advantage remains. For 4MOST, high and low latitude sample mock catalogs were supplied by the 4MOST team, and allocations were carried out with the proposed Echidna-based positioner geometry. At high latitudes, the resulting target completeness was 85.3% for LR targets and 78.9% for HR targets. At low latitude, the target completeness was 93.9% for LR targets and 71.2% for HR targets.

  6. Multilayered thermal insulation formed of zirconia bonded layers of zirconia fibers and metal oxide fibers and method for making same

    DOEpatents

    Wrenn, Jr., George E.; Holcombe, Jr., Cressie E.

    1988-01-01

    A multilayered thermal insulating composite is formed of a first layer of zirconia-bonded zirconia fibers for utilization near the hot phase or surface of a furnace or the like. A second layer of zirconia-bonded metal oxide fibers is attached to the zirconia fiber layer by a transition layer formed of intermingled zirconia fibers and metal oxide fibers. The thermal insulation is fabricated by vacuum molding with the layers being sequentially applied from aqueous solutions containing the fibers to a configured mandrel. A portion of the solution containing the fibers forming the first layer is intermixed with the solution containing the fibers of the second layer for forming the layer of mixed fibers. The two layers of fibers joined together by the transition layer are saturated with a solution of zirconium oxynitrate which provides a zirconia matrix for the composite when the fibers are sintered together at their nexi.

  7. Multilayered thermal insulation formed of zirconia bonded layers of zirconia fibers and metal oxide fibers and method for making same

    DOEpatents

    Wrenn, G.E. Jr.; Holcombe, C.E. Jr.

    1988-09-13

    A multilayered thermal insulating composite is formed of a first layer of zirconia-bonded zirconia fibers for utilization near the hot phase or surface of a furnace or the like. A second layer of zirconia-bonded metal oxide fibers is attached to the zirconia fiber layer by a transition layer formed of intermingled zirconia fibers and metal oxide fibers. The thermal insulation is fabricated by vacuum molding with the layers being sequentially applied from aqueous solutions containing the fibers to a configured mandrel. A portion of the solution containing the fibers forming the first layer is intermixed with the solution containing the fibers of the second layer for forming the layer of mixed fibers. The two layers of fibers joined together by the transition layer are saturated with a solution of zirconium oxynitrate which provides a zirconia matrix for the composite when the fibers are sintered together at their nexi.

  8. Oxidation-resistant interfacial coatings for continuous fiber ceramic composites

    SciTech Connect

    Stinton, D.P.; Besmann, T.M.; Bleier, A.; Shanmugham, S.; Liaw, P.K.

    1995-08-01

    Continuous fiber ceramic composites mechanical behavior are influenced by the bonding characteristics between the fiber and the matrix. Finite modeling studies suggest that a low-modulus interfacial coating material will be effective in reducing the residual thermal stresses that are generated upon cooling from processing temperatures. Nicalon{trademark}/SiC composites with carbon, alumina and mullite interfacial coatings were fabricated with the SiC matrix deposited using a forced-flow, thermal gradient chemical vapor infiltration process. Composites with mullite interfacial coatings exhibited considerable fiber pull-out even after oxidation and have potential as a composite system.

  9. Carbon and oxide coatings on continuous ceramic fibers

    SciTech Connect

    Hay, R.S.; Cinibulk, M.K.; Petry, M.D.; Keller, K.A.; Welch, J.R.

    1995-10-01

    Oxide-carbon multilayer coatings were continuously applied to various fibers of nominal SiC composition. A liquid-phase coating system that allows application of the coatings in a controlled atmosphere at relatively rapid rates was employed. Sugar-ammonium hydroxide solutions were used for carbon coatings, and aqueous sols were used for the oxides. Carbon was also deposited simultaneously with alumina by chemical vapor deposition of a hydrocarbon in the coating furnace. The coatings were extensively characterized by optical microscopy and TEM. Problems with embrittlement by oxide coatings and poor adherence of oxide coatings on carbon, and some possible solutions to these problems, are discussed.

  10. Recent developments in zinc oxide target chemistry

    SciTech Connect

    Heaton, R.C.; Taylor, W.A.; Phillips, D.R.; Jamriska, D.J. Sr.; Garcia, J.B.

    1994-04-01

    Zinc oxide targets irradiated with high energy protons at the Los Alamos Meson Physics Facility (LAMPF) contain a number of radioactive spallation products in quantities large enough to warrant recovery. This paper describes methods for recovering {sup 7}Be, {sup 46}Sc, and {sup 48}V from such targets and offers suggestions on possible ways to recover additional isotopes. The proposed methods are based on traditional precipitation and ion exchange techniques, are readily adaptable to hot cell use, and produce no hazardous waste components. The products are obtained in moderate to high yields and have excellent radiopurity.

  11. Target allocation yields for massively multiplexed spectroscopic surveys with fibers

    NASA Astrophysics Data System (ADS)

    Saunders, Will; Smedley, Scott; Gillingham, Peter; Forero-Romero, Jaime E.; Jouvel, Stephanie; Nord, Brian

    2014-08-01

    We present Simulated Annealing fiber-to-target allocation simulations for the proposed DESI and 4MOST massively multiplexed spectroscopic surveys. We simulate various survey strategies, for both Poisson and realistically clustered mock target samples. We simulate both Echidna and theta-phi actuator designs, including the restrictions caused by the physical actuator characteristics during repositioning. For DESI, with theta-phi actuators, used in 5 passes over the sky for a mock ELG/LRG/QSO sample, with matched fiber and target densities, a total target allocation yield of 89.3% was achieved, but only 83.7% for the high-priority Ly-alpha QSOs. If Echidna actuators are used with the same pitch and number of passes, the yield increases to 94.4% and 97.2% respectively, representing fractional gains of 5.7% and 16% respectively. Echidna also allows a factor-of-two increase in the number of close Ly-alpha QSO pairs that can be observed. Echidna spine tilt causes a variable loss of throughput, with average loss being the same as the loss at the rms tilt. The simulated annealing allows spine tilt minimization to be included in the optimization, at some small cost to the yield. With a natural minimization scheme, we find an rms tilt always close to 0.58 x maximum. There is an additional but much smaller defocus loss, equivalent to an average defocus of 30 μm. These tilt losses offset the gains in yield for Echidna, but because the survey strategy is driven by the higher priority targets, a clear survey speed advantage remains. For 4MOST, high and low latitude sample mock catalogs were supplied by the 4MOST team, and allocations were carried out with the proposed Echidna-based positioner geometry. At high latitudes, the resulting target completeness was 85.3% for LR targets and 78.9% for HR targets. At low latitude, the target completeness was 93.9% for LR targets and 71.2% for HR targets.

  12. Production of graphene oxide from pitch-based carbon fiber

    NASA Astrophysics Data System (ADS)

    Lee, Miyeon; Lee, Jihoon; Park, Sung Young; Min, Byunggak; Kim, Bongsoo; in, Insik

    2015-07-01

    Pitch-based graphene oxide (p-GO) whose compositional/structural features are comparable to those of graphene oxide (GO) was firstly produced by chemical exfoliation of pitch-based carbon fiber rather than natural graphite. Incorporation of p-GO as nanofillers into poly(methyl methacrylate) (PMMA) as a matrix polymer resulted in excellent mechanical reinforcement. p-GO/PMMA nanocomposite (1 wt.-% p-GO) demonstrated 800% higher modulus of toughness of neat PMMA.

  13. Production of graphene oxide from pitch-based carbon fiber

    PubMed Central

    Lee, Miyeon; Lee, Jihoon; Park, Sung Young; Min, Byunggak; Kim, Bongsoo; In, Insik

    2015-01-01

    Pitch-based graphene oxide (p-GO) whose compositional/structural features are comparable to those of graphene oxide (GO) was firstly produced by chemical exfoliation of pitch-based carbon fiber rather than natural graphite. Incorporation of p-GO as nanofillers into poly(methyl methacrylate) (PMMA) as a matrix polymer resulted in excellent mechanical reinforcement. p-GO/PMMA nanocomposite (1 wt.-% p-GO) demonstrated 800% higher modulus of toughness of neat PMMA. PMID:26156067

  14. Interphase for ceramic matrix composites reinforced by non-oxide ceramic fibers

    NASA Technical Reports Server (NTRS)

    DiCarlo, James A. (Inventor); Bhatt, Ramakrishna (Inventor); Morscher, Gregory N. (Inventor); Yun, Hee-Mann (Inventor)

    2008-01-01

    A ceramic matrix composite material is disclosed having non-oxide ceramic fibers, which are formed in a complex fiber architecture by conventional textile processes; a thin mechanically weak interphase material, which is coated on the fibers; and a non-oxide or oxide ceramic matrix, which is formed within the interstices of the interphase-coated fiber architecture. During composite fabrication or post treatment, the interphase is allowed to debond from the matrix while still adhering to the fibers, thereby providing enhanced oxidative durability and damage tolerance to the fibers and the composite material.

  15. Oxidation of Al2O3 continuous fiber-reinforced/NiAl composites

    NASA Technical Reports Server (NTRS)

    Doychak, J.; Nesbitt, J. A.; Noebe, R. D.; Bowman, R. R.

    1992-01-01

    The 1200 C and 1300 C isothermal and cyclic oxidation behavior of Al2O3 continuous fiber-reinforced/NiAl composites were studied. Oxidation resulted in formation of Al2O3 external scales in a similar manner as scales formed on monolithic NiAl. The isothermal oxidation of an Al2O3/NiAl composite resulted in oxidation of the matrix along the fiber/matrix interface near the fiber ends. This oxide acted as a wedge between the fiber and the matrix, and, under cyclic oxidation conditions, led to further oxidation along the fiber lengths and eventual cracking of the composite. The oxidation behavior of composites in which the Al2O3 fibers were sputter coated with nickel prior to processing was much more severe. This was attributed to open channels around the fibers which formed during processing, most likely as a result of the diffusion of the nickel coating into the matrix.

  16. Oxidation Behavior of Carbon Fiber-Reinforced Composites

    NASA Technical Reports Server (NTRS)

    Sullivan, Roy M.

    2008-01-01

    OXIMAP is a numerical (FEA-based) solution tool capable of calculating the carbon fiber and fiber coating oxidation patterns within any arbitrarily shaped carbon silicon carbide composite structure as a function of time, temperature, and the environmental oxygen partial pressure. The mathematical formulation is derived from the mechanics of the flow of ideal gases through a chemically reacting, porous solid. The result of the formulation is a set of two coupled, non-linear differential equations written in terms of the oxidant and oxide partial pressures. The differential equations are solved simultaneously to obtain the partial vapor pressures of the oxidant and oxides as a function of the spatial location and time. The local rate of carbon oxidation is determined at each time step using the map of the local oxidant partial vapor pressure along with the Arrhenius rate equation. The non-linear differential equations are cast into matrix equations by applying the Bubnov-Galerkin weighted residual finite element method, allowing for the solution of the differential equations numerically.

  17. Eliminating Crystals in Non-Oxide Optical Fiber Preforms and Optical Fibers

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; LaPointe, Michael R.

    2012-01-01

    Non ]oxide fiber optics such as heavy metal fluoride and chalcogenide glasses are extensively used in infrared transmitting applications such as communication systems, chemical sensors, and laser fiber guides for cutting, welding and medical surgery. The addition of rare earths such as erbium, enable these materials to be used as fiber laser and amplifiers. Some of these glasses however are very susceptible to crystallization. Even small crystals can lead to light scatter and a high attenuation coefficient, limiting their usefulness. Previously two research teams found that microgravity suppressed crystallization in heavy metal fluoride glasses. Looking for a less expensive method to suppress crystallization, ground based research was performed utilizing an axial magnetic field. The experiments revealed identical results to those obtained via microgravity processing. This research then led to a patented process for eliminating crystals in optical fiber preforms and the resulting optical fibers. In this paper, the microgravity results will be reviewed as well as patents and papers relating to the use of magnetic fields in various material and glass processing applications. Finally our patent to eliminate crystals in non ]oxide glasses utilizing a magnetic field will be detailed.

  18. Various-sourced pectin and polyethylene oxide electrospun fibers.

    PubMed

    Rockwell, Pamela L; Kiechel, Marjorie A; Atchison, Jennifer S; Toth, Laura J; Schauer, Caroline L

    2014-07-17

    Pectin, a naturally occurring and biorenewable polysaccharide, is derived from plant cell wall tissue and used in applications ranging from food processing to biomedical engineering. Due to extraction methods and source variation, there is currently no consensus in literature as to the exact structure of pectin. Here, we have studied key material properties of electrospun pectin blends with polyethylene oxide (PEO) (1:1, v/v) in order to demonstrate the fabrication of a fibrous and less toxic material system, as well as to understand the effects of source variability on the resulting fibrous mats. The bulk pectin degree of esterification (DE) estimated using FTIR (bulk apple pomace (AP)=28%, bulk citrus peel (CP)=86% and bulk sugar beet pulp (SBP)=91%) was shown to inversely correlate with electrospun fiber crystallinity determined using XRD (PEO-AP=37%, PEO-CP=28% and PEO-SBP=23%). This in turn affected the trend observed for the mean fiber diameter (n=50) (PEO-AP=124 ± 26 nm, PEO-CP=493 ± 254 nm and PEO-SBP=581 ± 178 nm) and elastic tensile moduli (1.6 ± 0.2 MPa, 4.37 ± 0.64 MPa and 2.49 ± 1.46 MPa, respectively) of the fibrous mats. Electrospun fibers containing bulk AP had the lowest DE, highest crystallinity, smallest mean fiber diameter, and lowest tensile modulus compared to either the bulk CP or bulk SBP. Bound water in PEO-CP fiber and bulk pectin impurities in PEO-SPB were observed to influence fiber branching and mean diameter distributions, which in turn influenced the fiber tensile properties. These results indicate that pectin, when blended with PEO in water, produces submicron fibrous mats with pectin influencing the blend fiber properties. Moreover, the source of pectin is an important variable in creating electrospun blend fibrous mats with desired material properties. PMID:24702925

  19. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection.

    PubMed

    Yao, B C; Wu, Y; Yu, C B; He, J R; Rao, Y J; Gong, Y; Fu, F; Chen, Y F; Li, Y R

    2016-01-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel 'FRET on Fiber' concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based 'FRET on fiber' configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated 'FRET on Fiber' sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response. PMID:27010752

  20. Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors

    NASA Astrophysics Data System (ADS)

    Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

    2014-07-01

    Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics. Electronic supplementary information (ESI) available: Equations and characterization. SEM images of GGO, XRD and XPS of Bi2O3 NTs, HRTEM images and EDX Spectra of Bi2O3 NT5-GF, CV curves of Bi2O3NT5-GF, Bi2O3 NTs and bismuth nitrate in three-electrode system (vs. Ag/AgCl). CV and GCD curves of Bi2O3 NT1-GF and Bi2O3 NT3-GF. See DOI: 10.1039/c4nr02615b

  1. Effect of fiber reinforcements on thermo-oxidative stability and mechanical properties of polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    1991-01-01

    A number of studies have investigated the thermo-oxidative behavior of polymer matrix composites. Two significant observations have been made from these research efforts: (1) fiber reinforcement has a significant effect on composite thermal stability; and (2) geometric effects must be considered when evaluating thermal aging data. A compilation of some results from these studies is presented, and this information shows the influence of the reinforcement fibers on the oxidative degradation of various polymer matrix composites. The polyimide PMR-15 was the matrix material that was used in these studies. The control composite material was reinforced with Celion 6000 graphite fiber. T-40R graphite fibers, along with some very stable ceramic fibers were selected as reinforcing fibers because of their high thermal stability. The ceramic fibers were Nicalon (silicon carbide) and Nextel 312 (alumina-silica-boron oxide). The mechanical properties of the two graphite fiber composites were significantly different, probably owing to variations in interfacial bonding between the fibers and the polyimide matrix. The Celion 6000/PMR-15 bond is very tight but the T-40/PMR-15 bond is less tight. Three oxidation mechanisms were observed: (1) the preferential oxidation of the Celion 6000 fiber ends at cut surfaces, leaving a surface of matrix material with holes where the fiber ends were originally situated; (2) preferential oxidation of the composite matrix; and (3) interfacial degradation by oxidation. The latter two mechanisms were also observed on fiber end cut surfaces. The fiber and interface attacks appeared to initiate interfiber cracking along these surfaces.

  2. Oxidation Behavior of Carbon Fiber Reinforced Silicon Carbide Composites

    NASA Technical Reports Server (NTRS)

    Valentin, Victor M.

    1995-01-01

    Carbon fiber reinforced Silicon Carbide (C-SiC) composites offer high strength at high temperatures and good oxidation resistance. However, these composites present some matrix microcracks which allow the path of oxygen to the fiber. The aim of this research was to study the effectiveness of a new Silicon Carbide (SiC) coating developed by DUPONT-LANXIDE to enhance the oxidation resistance of C-SiC composites. A thermogravimetric analysis was used to determine the oxidation rate of the samples at different temperatures and pressures. The Dupont coat proved to be a good protection for the SiC matrix at temperatures lower than 1240 C at low and high pressures. On the other hand, at temperatures above 1340 C the Dupont coat did not seem to give good protection to the composite fiber and matrix. Even though some results of the tests have been discussed, because of time restraints, only a small portion of the desired tests could be completed. Therefore, no major conclusions or results about the effectiveness of the coat are available at this time.

  3. Methionine oxidation reduces lag-times for amyloid-β(1-40) fiber formation but generates highly fragmented fibers.

    PubMed

    Gu, Miao; Viles, John H

    2016-09-01

    Oxidative stress and the formation of amyloid plaques containing amyloid-β (Aβ) peptides are two key hallmarks of Alzheimer's disease. A proportion of methionine (Met) at position 35 within Aβ is oxidized to methionine sulphoxide (Met(OX)) within the Alzheimer's plaques. These oxidative processes may be the key to understanding the early stages of Alzheimer's disease. In vitro oxidation of Aβ, by the physiological oxidant H2O2, was monitored using (1)H NMR and mass spectrometry. Here we investigate the effect of Aβ methionine oxidation on fiber formation kinetics and morphology using the amyloid specific fluorescence dye Thioflavin T (ThT) and Transmission Electron Microscopy (TEM). Methionine oxidation reduces the total amount of fibers generated for both dominant forms of Aβ, however there are marked differences in the effect of Met(OX) between Aβ(1-40) and Aβ(1-42). Surprisingly the presence of Met(OX) reduces lag-times for Aβ(1-40) fiber formation but extends lag-times for Aβ(1-42). TEM indicates a change in fiber morphology with a pronounced reduction in fiber length for both methionine oxidized Aβ(1-40) and Aβ(1-42). In contrast, the morphology of preformed amyloid fibers is largely unaffected by the presence of H2O2. Our studies suggest that methionine oxidation promotes highly fragmented fiber assemblies of Aβ. Oxidative stress associated with Alzheimer's disease can cause oxidation of methionine within Aβ and this in turn will influence the complex assembly of Aβ monomer into amyloid fibers, which is likely to impact Aβ toxicity. PMID:27108954

  4. A scintillating fiber-optic active target (SFT) for studies of high energy photoproduction

    SciTech Connect

    Ruchti, R.; Baumbaugh, B.; Bishop, J.; Busenitz, J.; Cason, N.; Cunningham, J.; Gardner, R.; Kennedy, C.; Mannel, E.; Mountain, R.J.

    1988-02-01

    A high resolution, gateable, Scintillating Fiber Target (SFT) has been developed for Fermilab Experiment E687 to study charm and beauty particle production and decay in high energy photon interactions. The detector consists of a scintillating target of either GS1 Cerium glass fibers or polystyrene fibers of 29..mu..m cross section, a multi-stage image intensifier and an intensified CCD or SIT/VIDICON camera system used in conjunction with a custom-built video data acquisition system.

  5. A novel electrospinning target to improve the yield of uniaxially aligned fibers.

    PubMed

    Secasanu, Virgil P; Giardina, Christopher K; Wang, Yadong

    2009-01-01

    Electrospinning is a useful technique that can generate micro and nanometer-sized fibers. Modification of the electrospinning parameters, such as deposition target geometry, can generate uniaxially aligned fibers for use in diverse applications ranging from tissue engineering to material fabrication. For example, meshes of fibers have been shown to mimic the extracellular matrix networks for use in smooth muscle cell proliferation. Further, aligned fibers can guide neurites to grow along the direction of the fibers. Here we present a novel electrospinning deposition target that combines the benefits of two previously reported electrodes: the standard parallel electrodes and the spinning wheel with a sharpened edge. This new target design significantly improves aligned fiber yield. Specifically, the target consists of two parallel aluminum plates with sharpened edges containing a bifurcating angle of 26 degrees. Electric field computations show a larger probable area of aligned electric field vectors. This new deposition target allows fibers to deposit on a larger cross-sectional area relative to the existing parallel electrode and at least doubles the yield of uniaxially aligned fibers. Further, fiber alignment and morphology are preserved after collection from the deposition target. PMID:19562742

  6. Respirometric Oxidative Phosphorylation Assessment in Saponin-permeabilized Cardiac Fibers

    PubMed Central

    Hughey, Curtis C.; Hittel, Dustin S.; Johnsen, Virginia L.; Shearer, Jane

    2011-01-01

    Investigation of mitochondrial function represents an important parameter of cardiac physiology as mitochondria are involved in energy metabolism, oxidative stress, apoptosis, aging, mitochondrial encephalomyopathies and drug toxicity. Given this, technologies to measure cardiac mitochondrial function are in demand. One technique that employs an integrative approach to measure mitochondrial function is respirometric oxidative phosphorylation (OXPHOS) analysis. The principle of respirometric OXPHOS assessment is centered around measuring oxygen concentration utilizing a Clark electrode. As the permeabilized fiber bundle consumes oxygen, oxygen concentration in the closed chamber declines. Using selected substrate-inhibitor-uncoupler titration protocols, electrons are provided to specific sites of the electron transport chain, allowing evaluation of mitochondrial function. Prior to respirometric analysis of mitochondrial function, mechanical and chemical preparatory techniques are utilized to permeabilize the sarcolemma of muscle fibers. Chemical permeabilization employs saponin to selectively perforate the cell membrane while maintaining cellular architecture. This paper thoroughly describes the steps involved in preparing saponin-skinned cardiac fibers for oxygen consumption measurements to evaluate mitochondrial OXPHOS. Additionally, troubleshooting advice as well as specific substrates, inhibitors and uncouplers that may be used to determine mitochondria function at specific sites of the electron transport chain are provided. Importantly, the described protocol may be easily applied to cardiac and skeletal tissue of various animal models and human samples. PMID:21403632

  7. Sensor materials for an intravascular fiber optic nitric oxide sensor

    NASA Astrophysics Data System (ADS)

    Soller, Babs R.; Parikh, Bhairavi R.; Stahl, Russell F.

    1996-04-01

    Nitric oxide (NO) is an important regulatory molecule in physiological processes including neurotransmission and the control of blood pressure. It is produced in excess during septic shock, the profound hypotensive state which accompanies severe infections. In-vivo measurement of NO would enhance the understanding of its varied biological roles. Our goal is the development of an intravascular fiber-optic sensor for the continuous measurement of NO. This study evaluated nitric oxide sensitive compounds as potential sensing materials in the presence and absence of oxygen. Using absorption spectroscopy we studied both the Fe II and Fe III forms of three biologically active hemes known to rapidly react with NO: hemoglobin, myoglobin, and cytochrome-c. The Fe II forms of hemoglobin and myoglobin and the Fe III form of cytochrome-c were found to have the highest sensitivity to NO. Cytochrome c (Fe III) is selective for NO even at high oxygen levels, while myoglobin is selective only under normal oxygen levels. NO concentrations as low as 1 (mu) M can be detected with our fiber-optic spectrometer using cytochrome c, and as low as 300 nM using myoglobin. Either of these materials would be adequate to monitor the increase in nitric oxide production during the onset of septic shock.

  8. Effects of Temperature, Oxidation and Fiber Preforms on Fatigue Life of Carbon Fiber-Reinforced Ceramic-Matrix Composites

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2016-08-01

    In this paper, the effects of temperature, oxidation and fiber preforms on the fatigue life of carbon fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) have been investigated. An effective coefficient of the fiber volume fraction along the loading direction (ECFL) was introduced to describe the fiber architecture of preforms. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface wear model and fibers statistical failure model at room temperature, and interface/fibers oxidation model, interface wear model and fibers statistical failure model at elevated temperatures in the oxidative environments. When the broken fibers fraction approaches to the critical value, the composites fatigue fracture. The fatigue life S-N curves and fatigue limits of unidirectional, cross-ply, 2D, 2.5D and 3D C/SiC composites at room temperature, 800 °C in air, 1100, 1300 and 1500 °C in vacuum conditions have been predicted.

  9. Effects of Temperature, Oxidation and Fiber Preforms on Fatigue Life of Carbon Fiber-Reinforced Ceramic-Matrix Composites

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2016-04-01

    In this paper, the effects of temperature, oxidation and fiber preforms on the fatigue life of carbon fiber-reinforced silicon carbide ceramic-matrix composites (C/SiC CMCs) have been investigated. An effective coefficient of the fiber volume fraction along the loading direction (ECFL) was introduced to describe the fiber architecture of preforms. Under cyclic fatigue loading, the fibers broken fraction was determined by combining the interface wear model and fibers statistical failure model at room temperature, and interface/fibers oxidation model, interface wear model and fibers statistical failure model at elevated temperatures in the oxidative environments. When the broken fibers fraction approaches to the critical value, the composites fatigue fracture. The fatigue life S-N curves and fatigue limits of unidirectional, cross-ply, 2D, 2.5D and 3D C/SiC composites at room temperature, 800 °C in air, 1100, 1300 and 1500 °C in vacuum conditions have been predicted.

  10. Fiber optic relative humidity sensor based on the tilted fiber Bragg grating coated with graphene oxide

    NASA Astrophysics Data System (ADS)

    Wang, Youqing; Shen, Changyu; Lou, Weimin; Shentu, Fengying; Zhong, Chuan; Dong, Xinyong; Tong, Limin

    2016-07-01

    A fiber optic relative humidity (RH) sensor based on the tilted fiber Bragg grating (TFBG) coated with graphene oxide (GO) film was presented. Amplitudes of the cladding mode resonances of the TFGB varies with the water sorption and desorption processes of the GO film, because of the strong interactions between the excited backward propagating cladding modes and the GO film. By detecting the transmission intensity changes of the cladding mode resonant dips at the wavelength of 1557 nm, the maximum sensitivity of 0.129 dB/%RH with a linear correlation coefficient of 99% under the RH range of 10-80% was obtained. The Bragg mode of TFBG can be used as power or wavelength references, since it is inherently insensitive to RH changes. In addition, the proposed humidity sensor shows a good performance in repeatability and stability.

  11. Effect of fiber reinforcement on thermo-oxidative stability and mechanical properties of polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Bowles, K. J.

    1992-01-01

    A number of studies have investigated the thermooxidative behavior of polymer matrix composites. Two significant observations have been made from these research efforts: (1) fiber reinforcement has a significant effect on composite thermal stability; and (2) geometric effects must be considered when evaluating thermal aging data. The polyimide PMR-15 was the matrix material used in these studies. The control composite material was reinforced with Celion 6000 graphite fiber. T-4OR graphite fibers, along with some very stable ceramic fibers were selected as reinforcing fibers because of their high thermal stability. The ceramic fibers were Nicalon (silicon carbide) and Nextel 312 (alumina-silica-boron oxide). The mechanical properties of the two graphite fiber composites were significantly different, probably owing to variations in interfacial bonding between the fibers and the polyimide matrix. Three oxidation mechanisms were observed: (1) the preferential oxidation of the Celion 6000 fiber ends at cut surfaces, leaving a surface of matrix material with holes where the fiber ends were originally situated; (2) preferential oxidation of the composite matrix; and (3) interfacial degradation by oxidation. The latter two mechanisms were also observed on fiber end cut surfaces. The fiber and interface attacks appeared to initiate interfiber cracking along these surfaces.

  12. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi.

    1990-05-22

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed. 2 figs.

  13. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi

    1990-01-01

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed.

  14. A Comparative Study of Natural Fiber and Glass Fiber Fabrics Properties with Metal or Oxide Coatings

    NASA Astrophysics Data System (ADS)

    Lusis, Andrej; Pentjuss, Evalds; Bajars, Gunars; Sidorovicha, Uljana; Strazds, Guntis

    2015-03-01

    Rapidly growing global demand for technical textiles industries is stimulated to develop new materials based on hybrid materials (yarns, fabrics) made from natural and glass fibres. The influence of moisture on the electrical properties of metal and metal oxide coated bast (flax, hemp) fibre and glass fibre fabrics are studied by electrical impedance spectroscopy and thermogravimetry. The bast fibre and glass fiber fabrics are characterized with electrical sheet resistance. The method for description of electrical sheet resistance of the metal and metal oxide coated technical textile is discussed. The method can be used by designers to estimate the influence of moisture on technical data of new metal coated hybrid technical textile materials and products.

  15. Combining Untargeted and Targeted Proteomic Strategies for Discrimination and Quantification of Cashmere Fibers

    PubMed Central

    Li, Shanshan; Zhang, Yong; Wang, Jihua; Yang, Yunfei; Miao, Chen; Guo, Yufeng; Zhang, Zhidan; Cao, Qichen; Shui, Wenqing

    2016-01-01

    Cashmere is regarded as a specialty and luxury fiber due to its scarcity and high economic value. For fiber quality assessment, it is technically very challenging to distinguish and quantify the cashmere fiber from yak or wool fibers because of their highly similar physical appearance and substantial protein sequence homology. To address this issue, we propose a workflow combining untargeted and targeted proteomics strategies for selecting, verifying and quantifying biomarkers for cashmere textile authentication. Untargeted proteomic surveys were first applied to identify 174, 157, and 156 proteins from cashmere, wool and yak fibers, respectively. After marker selection at different levels, peptides turned out to afford much higher selectivity than proteins for fiber species discrimination. Subsequently, parallel reaction monitoring (PRM) methods were developed for ten selected peptide markers. The PRM-based targeted analysis of peptide markers enabled accurate determination of fiber species and cashmere percentages in different fiber mixtures. Furthermore, collective use of these peptide makers allowed us to discriminate and quantify cashmere fibers in commercial finished fabrics that have undergone heavy chemical treatments. Cashmere proportion measurement in fabric samples using our proteomic approach was in good agreement with results from traditional light microscopy, yet our method can be more readily standardized to become an objective and robust assay for assessing authenticity of fibers and textiles. We anticipate that the proteomic strategies presented in our study could be further implicated in discovery of quality trait markers for other products containing highly homologous proteomes. PMID:26789629

  16. Combining Untargeted and Targeted Proteomic Strategies for Discrimination and Quantification of Cashmere Fibers.

    PubMed

    Li, Shanshan; Zhang, Yong; Wang, Jihua; Yang, Yunfei; Miao, Chen; Guo, Yufeng; Zhang, Zhidan; Cao, Qichen; Shui, Wenqing

    2016-01-01

    Cashmere is regarded as a specialty and luxury fiber due to its scarcity and high economic value. For fiber quality assessment, it is technically very challenging to distinguish and quantify the cashmere fiber from yak or wool fibers because of their highly similar physical appearance and substantial protein sequence homology. To address this issue, we propose a workflow combining untargeted and targeted proteomics strategies for selecting, verifying and quantifying biomarkers for cashmere textile authentication. Untargeted proteomic surveys were first applied to identify 174, 157, and 156 proteins from cashmere, wool and yak fibers, respectively. After marker selection at different levels, peptides turned out to afford much higher selectivity than proteins for fiber species discrimination. Subsequently, parallel reaction monitoring (PRM) methods were developed for ten selected peptide markers. The PRM-based targeted analysis of peptide markers enabled accurate determination of fiber species and cashmere percentages in different fiber mixtures. Furthermore, collective use of these peptide makers allowed us to discriminate and quantify cashmere fibers in commercial finished fabrics that have undergone heavy chemical treatments. Cashmere proportion measurement in fabric samples using our proteomic approach was in good agreement with results from traditional light microscopy, yet our method can be more readily standardized to become an objective and robust assay for assessing authenticity of fibers and textiles. We anticipate that the proteomic strategies presented in our study could be further implicated in discovery of quality trait markers for other products containing highly homologous proteomes. PMID:26789629

  17. Delivery of Erbium:YAG laser radiation through side-firing germanium oxide optical fibers

    NASA Astrophysics Data System (ADS)

    Ngo, Anthony K.; Fried, Nathaniel M.

    2006-02-01

    The Erbium:YAG laser is currently being tested experimentally for endoscopic applications in urology, including more efficient laser lithotripsy and more precise incision of urethral strictures than the Holmium:YAG laser. While side-firing silica fibers are available for use with the Ho:YAG laser in urology, no such fibers exist for use with the Er:YAG laser. These applications may benefit from the availability of a side-firing, mid-infrared optical fiber capable of delivering the laser radiation at a 90-degree angle to the tissue. The objective of this study is to describe the simple construction and characterization of a side-firing germanium oxide fiber for potential use in endoscopic laser surgery. Side-firing fibers were constructed from 450-micron-core germanium oxide fibers of 1.45-m-length by polishing the distal tip at a 45-degree angle and placing a 1-cm-long protective quartz cap over the fiber tip. Er:YAG laser radiation with a wavelength of 2.94 microns, pulse duration of 300 microseconds, pulse repetition rate of 3 Hz, and pulse energies of from 5 to 550 mJ was coupled into the fibers. The fiber transmission rate and damage threshold measured 48 +/- 4 % and 149 +/- 37 mJ, respectively (n = 6 fibers). By comparison, fiber transmission through normal germanium oxide trunk fibers measured 66 +/- 3 %, with no observed damage (n = 5 fibers). Sufficient pulse energies were transmitted through the side-firing fibers for contact tissue ablation. Although these initial tests are promising, further studies will need to be conducted, focusing on assembly of more flexible, smaller diameter fibers, fiber bending transmission tests, long-term fiber reliability tests, and improvement of the fiber output spatial beam profile.

  18. The role of nitric oxide in muscle fibers with oxidative phosphorylation defects

    SciTech Connect

    Tengan, Celia H. . E-mail: chtengan@neuro.epm.br; Kiyomoto, Beatriz H.; Godinho, Rosely O.; Gamba, Juliana; Neves, Afonso C.; Schmidt, Beny; Oliveira, Acary S.B.; Gabbai, Alberto A.

    2007-08-03

    NO has been pointed as an important player in the control of mitochondrial respiration, especially because of its inhibitory effect on cytochrome c oxidase (COX). However, all the events involved in this control are still not completely elucidated. We demonstrate compartmentalized abnormalities on nitric oxide synthase (NOS) activity on muscle biopsies of patients with mitochondrial diseases. NOS activity was reduced in the sarcoplasmic compartment in COX deficient fibers, whereas increased activity was found in the sarcolemma of fibers with mitochondrial proliferation. We observed increased expression of neuronal NOS (nNOS) in patients and a correlation between nNOS expression and mitochondrial content. Treatment of skeletal muscle culture with an NO donor induced an increase in mitochondrial content. Our results indicate specific roles of NO in compensatory mechanisms of muscle fibers with mitochondrial deficiency and suggest the participation of nNOS in the signaling process of mitochondrial proliferation in human skeletal muscle.

  19. RADIATION-RESISTANT FIBER OPTIC STRAIN SENSORS FOR SNS TARGET INSTRUMENTATION

    SciTech Connect

    Blokland, Willem; Bryan, Jeff; Riemer, Bernie; Sangrey, Robert L; Wendel, Mark W; Liu, Yun

    2016-01-01

    Measurement of stresses and strains in the mercury tar-get vessel of the Spallation Neutron Source (SNS) is important to understand the structural dynamics of the target. This work reports the development of radiation-resistant fiber optic strain sensors for the SNS target in-strumentation.

  20. Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various fibers

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    1990-01-01

    An experimental study was conducted to measure the thermo-oxidative stability of PMR-15 polymer matrix composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers that were studied included graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber-sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

  1. Electrical and optical characterization of copper oxide/calcium oxide nanocomposite fibers.

    PubMed

    Vijayakumar, G Nixon Samuel

    2014-04-01

    The Poly(vinyl alcohol)/copper acetate/calcium acetate sol was prepared by sol-gel route. Poly(vinyl alcohol)/copper acetate/calcium acetate composite nanofibers were synthesized by electrospinning process. These nanofibers had an average diameter of 200 nm. Calcining these fibers at 1000 degrees C produced copper oxide/calcium oxide nanofibers with average diameter of 75 nm. These fibers were characterized by Atomic Force Microscopy, Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy, powder X-ray Diffraction, Ultraviolet spectroscopy, dielectric study and Second Harmonic Generation (SHG) efficiency test. Band gap energy was calculated as 4.1 eV. SHG efficiency was found to be 1.7 times than that of KDP. PMID:24734744

  2. Helical graphene oxide fibers as a stretchable sensor and an electrocapillary sucker.

    PubMed

    Hua, Chunfei; Shang, Yuanyuan; Li, Xiying; Hu, Xiaoyang; Wang, Ying; Wang, Xinchang; Zhang, Yingjiu; Li, Xinjian; Duan, Huiling; Cao, Anyuan

    2016-05-19

    Fibers made from carbon nanotubes or graphene are strong and conductive; encoding helical structures into these fibers may render useful properties such as high stretchability. Here, we directly spin freestanding graphene oxide (GO) films into helical fibers consisting of uniformly arranged loops with tunable diameters, under controlled environmental humidity. Reduced GO fibers with a helical shape are stretched elastically with a reversible electrical resistance change for many strain cycles. Stretchable temperature sensors built on helical fibers work at large strains (up to 50%) and high temperature (up to 300 °C), with a reliable deformation-independent response. The GO fibers also contain through-channels inside with suitable pore size, which can take up an aqueous electrolyte quickly under a low bias, resulting in a fiber-shaped, on-off switchable electrocapillary sucker. Our multifunctional helical and hollow GO fibers have potential applications in stretchable fiber-shaped sensors, actuators and nano-fluid systems. PMID:27147483

  3. A scintillating fiber-optic active target (SFT) for studies of high energy photoproduction

    SciTech Connect

    Ruchti, R.; Baumbaugh, B.; Bishop, J.; Busenitz, J.; Cason, N.; Cunningham, J.; Gardner, R.; Kennedy, C.; Mannel, E.; Mountain, R.J.

    1987-10-01

    A high resolution, gateable, Scintillating Fiber Target (SFT) has been developed for Fermilab Experiment E687 to study charm and beauty particle production and decay in high energy photon interactions. The detector consists of a scintillating target of either GS1 Cerium glass fibers or polystyrene fibers of 29..mu..m cross section, a multi-stage image intensifier and an intensified CCD or SIT/VIDICON camera system used in conjunction with a custom-built video data acquisition system. 7 refs., 8 figs., 1 tab.

  4. Helical graphene oxide fibers as a stretchable sensor and an electrocapillary sucker

    NASA Astrophysics Data System (ADS)

    Hua, Chunfei; Shang, Yuanyuan; Li, Xiying; Hu, Xiaoyang; Wang, Ying; Wang, Xinchang; Zhang, Yingjiu; Li, Xinjian; Duan, Huiling; Cao, Anyuan

    2016-05-01

    Fibers made from carbon nanotubes or graphene are strong and conductive; encoding helical structures into these fibers may render useful properties such as high stretchability. Here, we directly spin freestanding graphene oxide (GO) films into helical fibers consisting of uniformly arranged loops with tunable diameters, under controlled environmental humidity. Reduced GO fibers with a helical shape are stretched elastically with a reversible electrical resistance change for many strain cycles. Stretchable temperature sensors built on helical fibers work at large strains (up to 50%) and high temperature (up to 300 °C), with a reliable deformation-independent response. The GO fibers also contain through-channels inside with suitable pore size, which can take up an aqueous electrolyte quickly under a low bias, resulting in a fiber-shaped, on-off switchable electrocapillary sucker. Our multifunctional helical and hollow GO fibers have potential applications in stretchable fiber-shaped sensors, actuators and nano-fluid systems.Fibers made from carbon nanotubes or graphene are strong and conductive; encoding helical structures into these fibers may render useful properties such as high stretchability. Here, we directly spin freestanding graphene oxide (GO) films into helical fibers consisting of uniformly arranged loops with tunable diameters, under controlled environmental humidity. Reduced GO fibers with a helical shape are stretched elastically with a reversible electrical resistance change for many strain cycles. Stretchable temperature sensors built on helical fibers work at large strains (up to 50%) and high temperature (up to 300 °C), with a reliable deformation-independent response. The GO fibers also contain through-channels inside with suitable pore size, which can take up an aqueous electrolyte quickly under a low bias, resulting in a fiber-shaped, on-off switchable electrocapillary sucker. Our multifunctional helical and hollow GO fibers have potential

  5. Cellulose nanowhiskers extracted from TEMPO-oxidized jute fibers.

    PubMed

    Cao, Xinwang; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S

    2012-10-01

    Cellulose nanowhiskers is a kind of renewable and biocompatible nanomaterials evoke much interest because of its versatility in various applications. Here, for the first time, a novel controllable fabrication of cellulose nanowhiskers from jute fibers with a high yield (over 80%) via a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/NaBr/NaClO system selective oxidization combined with mechanical homogenization is reported. The versatile jute cellulose nanowhiskers with ultrathin diameters (3-10 nm) and high crystallinity (69.72%), contains C6 carboxylate groups converted from C6 primary hydroxyls, which would be particularly useful for applications in the nanocomposites as reinforcing phase, as well as in tissue engineering, pharmaceutical and optical industries as additives. PMID:22840042

  6. The Regulation of Corticofugal Fiber Targeting by Retinal Inputs

    PubMed Central

    Grant, Eleanor; Hoerder-Suabedissen, Anna; Molnár, Zoltán

    2016-01-01

    Corticothalamic projection systems arise from 2 main cortical layers. Layer V neurons project exclusively to higher-order thalamic nuclei, while layer VIa fibers project to both first-order and higher-order thalamic nuclei. During early postnatal development, layer VIa and VIb fibers accumulate at the borders of the dorsal lateral geniculate nucleus (dLGN) before they innervate it. After neonatal monocular enucleation or silencing of the early retinal activity, there is premature entry of layer VIa and VIb fibers into the dLGN contralateral to the manipulation. Layer V fibers do not innervate the superficial gray layer of the superior colliculus during the first postnatal week, but also demonstrate premature entry to the contralateral superficial gray layer following neonatal enucleation. Normally, layer V driver projections to the thalamus only innervate higher-order nuclei. Our results demonstrate that removal of retinal input from the dLGN induces cortical layer V projections to aberrantly enter, arborize, and synapse within the first-order dLGN. These results suggest that there is cross-hierarchical corticothalamic plasticity after monocular enucleation. Cross-hierarchical rewiring has been previously demonstrated in the thalamocortical system (Pouchelon et al. 2014), and now we provide evidence for cross-hierarchical corticothalamic rewiring after loss of the peripheral sensory input. PMID:26744542

  7. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection

    PubMed Central

    Yao, B. C.; Wu, Y.; Yu, C. B.; He, J. R.; Rao, Y. J.; Gong, Y.; Fu, F.; Chen, Y. F.; Li, Y. R.

    2016-01-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel ‘FRET on Fiber’ concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based ‘FRET on fiber’ configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated ‘FRET on Fiber’ sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response PMID:27010752

  8. Partially reduced graphene oxide based FRET on fiber-optic interferometer for biochemical detection

    NASA Astrophysics Data System (ADS)

    Yao, B. C.; Wu, Y.; Yu, C. B.; He, J. R.; Rao, Y. J.; Gong, Y.; Fu, F.; Chen, Y. F.; Li, Y. R.

    2016-03-01

    Fluorescent resonance energy transfer (FRET) with naturally exceptional selectivity is a powerful technique and widely used in chemical and biomedical analysis. However, it is still challenging for conventional FRET to perform as a high sensitivity compact sensor. Here we propose a novel ‘FRET on Fiber’ concept, in which a partially reduced graphene oxide (prGO) film is deposited on a fiber-optic modal interferometer, acting as both the fluorescent quencher for the FRET and the sensitive cladding for optical phase measurement due to refractive index changes in biochemical detection. The target analytes induced fluorescence recovery with good selectivity and optical phase shift with high sensitivity are measured simultaneously. The functionalized prGO film coated on the fiber-optic interferometer shows high sensitivities for the detections of metal ion, dopamine and single-stranded DNA (ssDNA), with detection limits of 1.2 nM, 1.3 μM and 1 pM, respectively. Such a prGO based ‘FRET on fiber’ configuration, bridging the FRET and the fiber-optic sensing technology, may serve as a platform for the realization of series of integrated ‘FRET on Fiber’ sensors for on-line environmental, chemical, and biomedical detection, with excellent compactness, high sensitivity, good selectivity and fast response

  9. Interfacial microstructure and properties of carbon fiber composites modified with graphene oxide.

    PubMed

    Zhang, Xiaoqing; Fan, Xinyu; Yan, Chun; Li, Hongzhou; Zhu, Yingdan; Li, Xiaotuo; Yu, Liping

    2012-03-01

    The performance of carbon fiber-reinforced composites is dependent to a great extent on the properties of fiber-matrix interface. To improve the interfacial properties in carbon fiber/epoxy composites, we directly introduced graphene oxide (GO) sheets dispersed in the fiber sizing onto the surface of individual carbon fibers. The applied graphite oxide, which could be exfoliated to single-layer GO sheets, was verified by atomic force microscope (AFM). The surface topography of modified carbon fibers and the distribution of GO sheets in the interfacial region of carbon fibers were detected by scanning electron microscopy (SEM). The interfacial properties between carbon fiber and matrix were investigated by microbond test and three-point short beam shear test. The tensile properties of unidirectional (UD) composites were investigated in accordance with ASTM standards. The results of the tests reveal an improved interfacial and tensile properties in GO-modified carbon fiber composites. Furthermore, significant enhancement of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and tensile properties was achieved in the composites when only 5 wt % of GO sheets introduced in the fiber sizing. This means that an alternative method for improving the interfacial and tensile properties of carbon fiber composites by controlling the fiber-matrix interface was developed. Such multiscale reinforced composites show great potential with their improved mechanical performance to be likely applied in the aerospace and automotive industries. PMID:22391332

  10. FETs Based on Doped Polyaniline/Polyethylene Oxide Fibers

    NASA Technical Reports Server (NTRS)

    Theofylaktos, Noulie; Robinson, Daryl; Miranda, Felix; Pinto, Nicholas; Johnson, Alan, Jr.; MacDiarmid, Alan; Mueller, Carl

    2006-01-01

    A family of experimental highly miniaturized field-effect transistors (FETs) is based on exploitation of the electrical properties of nanofibers of polyaniline/ polyethylene oxide (PANi/PEO) doped with camphorsulfonic acid. These polymer-based FETs have the potential for becoming building blocks of relatively inexpensive, low-voltage, highspeed logic circuits that could supplant complementary metal oxide/semiconductor (CMOS) logic circuits. The development of these polymerbased FETs offers advantages over the competing development of FETs based on carbon nanotubes. Whereas it is difficult to control the molecular structures and, hence, the electrical properties of carbon nanotubes, it is easy to tailor the electrical properties of these polymerbased FETs, throughout the range from insulating through semiconducting to metallic, through choices of doping levels and chemical manipulation of polymer side chains. A further advantage of doped PANi/PEO nanofibers is that they can be made to draw very small currents and operate at low voltage levels, and thus are promising for applications in which there are requirements to use many FETs to obtain large computational capabilities while minimizing power demands. Fabrication of an experimental FET in this family begins with the preparation of a substrate as follows: A layer of silicon dioxide between 50 and 200 nm thick is deposited on a highly doped (resistivity 0.01 W.cm) silicon substrate, then gold electrodes/contact stripes are deposited on the oxide. Next, one or more fibers of camphorsulphonic acid-doped PANi/PEO having diameters of the order of 100 nm are electrospun onto the substrate so as to span the gap between the gold electrodes (see Figure 1). Figure 2 depicts measured current-versus-voltage characteristics of the device of Figure 1, showing that saturation channel currents occur at source-todrain potentials that are surprisingly low, relative to those of CMOS FETs. The hole mobility in the depletion regime in

  11. Oxidation Kinetics and Strength Degradation of Carbon Fibers in a Cracked Ceramic Matrix Composite

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2003-01-01

    Experimental results and oxidation modeling will be presented to discuss carbon fiber susceptibility to oxidation, the oxidation kinetics regimes and composite strength degradation and failure due to oxidation. Thermogravimetric Analysis (TGA) was used to study the oxidation rates of carbon fiber and of a pyro-carbon interphase. The analysis was used to separately obtain activation energies for the carbon constituents within a C/SiC composite. TGA was also conducted on C/SiC composite material to study carbon oxidation and crack closure as a function of temperature. In order to more closely match applications conditions C/SiC tensile coupons were also tested under stressed oxidation conditions. The stressed oxidation tests show that C/SiC is much more susceptible to oxidation when the material is under an applied load where the cracks are open and allow for oxygen ingress. The results help correlate carbon oxidation with composite strength reduction and failure.

  12. Dissolution of Neptunium Oxide in Unirradiated Mark 53 Targets

    SciTech Connect

    Rudisill, T.S.

    2002-06-07

    Nine unirradiated Mark 53 targets currently stored at the K-Reactor must be dissolved to allow recovery of the neptunium content. The Mark 53 targets are an aluminum clad neptunium oxide (NpO2)/aluminum metal cermet used for the production of plutonium-238. The targets will be dissolved in H-Canyon and blended with solutions generated from routine fuel dissolutions for purification by solvent extraction

  13. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2001-01-01

    A process for producing polycrystalline silicon carbide by heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  14. Process to produce silicon carbide fibers using a controlled concentration of boron oxide vapor

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Lipowitz, Jonathan (Inventor); Nguyen, Kimmai Thi (Inventor)

    2000-01-01

    A process for producing polycrystalline silicon carbide includes heating an amorphous ceramic fiber that contains silicon and carbon in an environment containing boron oxide vapor. The boron oxide vapor is produced in situ by the reaction of a boron containing material such as boron carbide and an oxidizing agent such as carbon dioxide, and the amount of boron oxide vapor can be controlled by varying the amount and rate of addition of the oxidizing agent.

  15. Demonstration of nitric oxide on asbestos and silicon carbide fibers with a new ultraviolet spectrophotometric assay.

    PubMed Central

    Leanderson, P; Lagesson, V; Tagesson, C

    1997-01-01

    Nitric oxide (NO) has a number of important functions in biological systems and may play a role in the toxicity of mineral fibers. We investigated whether NO might be present on the surface of mineral fibers and if crocidolite could adsorb NO from NO gas or cigarette smoke. NO was determined with a new gas chromatography-ultraviolet spectrophotometric technique after thermal desorption from the fiber surface and injection in a gas flow cell. NO was found in different amounts on chrysotile B, crocidolite, amosite, and silicon carbide whiskers. There was a strong correlation between the amount of NO and the specific surface area of these fibers (r = 0.98). NO could not be demonstrated on rockwool fibers [man-made vitreous fiber(s) (MMVF)21 and MMVF22] or silicon nitride whiskers. NO on crocidolite, amosite, and silicon carbide whiskers was readily desorbed from the fibers at increased temperature, while NO on chrysotile B seemed to be more firmly adsorbed to the fiber and required a longer period of time to be desorbed. The amount of NO bound to crocidolite increased from 34 micrograms/g fiber to 85 and 474 micrograms/g after exposing the fibers to cigarette smoke and NO gas, respectively. These findings indicate that a) NO adsorbs to fiber surfaces, b) some fibers adsorb more NO than others, c) some fibers adsorb NO more strongly than others, and d) the amounts of NO on fibers may be increased after exposure of the fiber to cigarette smoke or other sources of NO. The biological significance of NO on mineral fibers remains to be investigated. Images Figure 3. PMID:9400696

  16. Encapsulation of T4 bacteriophage in electrospun poly(ethylene oxide)/cellulose diacetate fibers.

    PubMed

    Korehei, Reza; Kadla, John F

    2014-01-16

    Phage therapy is a potentially beneficial approach to food preservation and storage. Sustained delivery of bacteriophage can prevent bacterial growth on contaminated food surfaces. Using coaxial electrospinning bacteriophage can be encapsulated in electrospun fibers with high viability. The resulting bio-based electrospun fibers may have potential as a food packaging material. In the present work, T4 bacteriophage (T4 phage) was incorporated into core/shell electrospun fibers made from poly(ethylene oxide) (PEO), cellulose diacetate (CDA), and their blends. Fibers prepared using PEO as the shell polymer showed an immediate burst release of T4 phage upon submersion in buffer. The blending of CDA with PEO significantly decreased the rate of phage release, with no released T4 phage being detected from the solely CDA fibers. Increasing the PEO molecular weight increased the electrospun fiber diameter and viscosity of the releasing medium, which resulted in a relatively slower T4 phage release profile. SEM analyses of the electrospun fiber morphologies were in good agreement with the T4 phage release profiles. Depending on the PEO/CDA ratio, the post-release electrospun fiber morphologies varied from discontinuous fibers to minimally swollen fibers. From these results it is suggested that the T4 phage release mechanism is through solvent activation/polymer dissolution in the case of the PEO fibers and/or by diffusion control from the PEO/CDA blend fibers. PMID:24188849

  17. Relative sliding durability of two candidate high temperature oxide fiber seal materials

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Steinetz, Bruce M.

    1991-01-01

    A test program to determine the relative sliding durability of two candidate ceramic fibers for high temperature sliding seal applications is described. Pin on disk tests were used to evaluate potential seal materials. Friction during the tests and fiber wear, indicated by the extent of fibers broken in a test bundle or yarn, was measured at the end of a test. In general, friction and wear increase with test temperature. This may be due to a reduction in fiber strength, a change in the surface chemistry at the fiber/counterface interface due to oxidation, adsorption and/or desorption of surface species and, to a lesser extent, an increase in counterface surface roughness due to oxidation at elevated temperatures. The relative fiber durability correlates with tensile strength indicating that tensile data, which is more readily available than sliding durability data, may be useful in predicting fiber wear behavior under various conditions. A simple model developed using dimensional analysis shows that the fiber durability is related to a dimensionless parameter which represents the ratio of the fiber strength to the fiber stresses imposed by sliding.

  18. Electrospun Contrast-Agent-Loaded Fibers for Colon-Targeted MRI.

    PubMed

    Jin, Miao; Yu, Deng-Guang; Wang, Xia; Geraldes, Carlos F G C; Williams, Gareth R; Bligh, S W Annie

    2016-04-01

    Magnetic resonance imaging is a diagnostic tool used for detecting abnormal organs and tissues, often using Gd(III) complexes as contrast-enhancing agents. In this work, core-shell polymer fibers have been prepared using coaxial electrospinning, with the intent of delivering gadolinium (III) diethylenetriaminepentaacetate hydrate (Gd(DTPA)) selectively to the colon. The fibers comprise a poly(ethylene oxide) (PEO) core loaded with Gd(DTPA), and a Eudragit S100 shell. They are homogeneous, with distinct core-shell phases. The components in the fibers are dispersed in an amorphous fashion. The proton relaxivities of Gd(DTPA) are preserved after electrospinning. To permit easy visualization of the release of the active ingredient from the fibers, analogous materials are prepared loaded with the dye rhodamine B. Very little release is seen in a pH 1.0 buffer, while sustained release is seen at pH 7.4. The fibers thus have the potential to selectively deliver Gd(DTPA) to the colon. Mucoadhesion studies reveal there are strong adhesive forces between porcine colon mucosa and PEO from the core, and the dye-loaded fibers can be successfully used to image the porcine colon wall. The electrospun core-shell fibers prepared in this work can thus be developed as advanced functional materials for effective imaging of colonic abnormalities. PMID:26899401

  19. Zinc Oxide Nanowire Interphase for Enhanced Lightweight Polymer Fiber Composites

    NASA Technical Reports Server (NTRS)

    Sodano, Henry A.; Brett, Robert

    2011-01-01

    The objective of this work was to increase the interfacial strength between aramid fiber and epoxy matrix. This was achieved by functionalizing the aramid fiber followed by growth of a layer of ZnO nanowires on the fiber surface such that when embedded into the polymer, the load transfer and bonding area could be substantially enhanced. The functionalization procedure developed here created functional carboxylic acid surface groups that chemically interact with the ZnO and thus greatly enhance the strength of the interface between the fiber and the ZnO.

  20. Adhesion enhancement of indium tin oxide (ITO) coated quartz optical fibers

    NASA Astrophysics Data System (ADS)

    Wang, Yihua; Liu, Jing; Wu, Xu; Yang, Bin

    2014-07-01

    Transparent conductive indium tin oxide (ITO) film was prepared on optical fiber through a multi-step sol-gel process. The influence of annealing temperature on the adhesion of ITO coated optical fibers was studied. Different surface treatments were applied to improve the adhesion between ITO film and quartz optical fiber. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), UV-vis spectrophotometer and Avometer were used to characterize the morphology, crystal structure and photo-electric properties. A thermal shock test was used to evaluate the adhesion. The result shows that the adhesion between ITO film and quartz optical fiber can be strongly influenced by the annealing process, and optimal adhesion can be acquired when annealing temperature is 500 °C. Surface treatments of ultrasonic cleaning and the application of surface-active agent have effectively enhanced the adhesion and photo-electric properties of indium tin oxide film coated quartz optical fiber.

  1. Effect of plasma etching on destructive adsorption properties of polypropylene fibers containing magnesium oxide nanoparticles.

    PubMed

    Lange, Laura E; Obendorf, S Kay

    2012-02-01

    Dermal absorption of pesticides poses a danger for agricultural workers. Use of personal protection equipment (PPE) is required to provide protection; some of the current PPE involves impermeable barriers. In these barrier materials, the same mechanism that prevents the penetration of toxic chemicals also blocks the passage of water vapor and air from flowing through the material, making the garments uncomfortable. Fibers that degrade organophosphate pesticides, such as methyl parathion, were developed by incorporating metal oxides. These modified fibers can be incorporated into conventional fabric structures that allow water vapor to pass through, thereby maintaining comfort. Fibers with self-decontamination functionality were developed by incorporating magnesium oxide (MgO) nanoparticles into a polypropylene (PP) melt-extruded fiber. These fibers were then treated with plasma etching to expose increased surface area of the MgO nanoparticles. Three steps were involved in this research project: (1) determining the reactivity of MgO and methyl parathion, (2) making melt-spun MgO/PP fibers, and (3) testing the reactivity of MgO/PP composite fibers and methyl parathion. It was confirmed that MgO stoichiometrically degrades methyl parathion by way of destructive adsorption. The etching of the PP fibers containing MgO nanoparticles increased the chemical accessibility of MgO reactive sites, therefore making them more effective in degrading methyl parathion. These fibers can enhance the protection provided by PPE to agricultural and horticultural workers and military personnel. PMID:21850511

  2. Effects of Graphene Oxide Modified Sizing Agents on Interfacial Properties of Carbon Fibers/Epoxy Composites.

    PubMed

    Zhang, Qingbo; Jiang, Dawei; Liu, Li; Huang, Yudong; Long, Jun; Wu, Guangshun; Wu, Zijian; Umar, Ahmad; Guo, Jiang; Zhang, Xi; Guo, Zhanhu

    2015-12-01

    A kind of graphene oxide (GO) modified sizing agent was used to improve the interfacial properties of carbon fibers/epoxy composites. The surface topography of carbon fibers was investigated by scanning electron microscopy (SEM). The surface compositions of carbon fibers were determined by X-ray photoelectron spectroscopy (XPS) and the interfacial properties of composites were studied by interlaminar shear strength (ILSS). The results show that the existence of GO increases the content of reactive functional groups on carbon fiber surface. Thus it enhances the interfacial properties of carbon fibers/epoxy composites. When GO loading in sizing agents is 1 wt%, the ILSS value of composite reaches to 96.2 MPa, which is increased by 27.2% while comparing with unsized carbon fiber composites. Furthermore, the ILSS of composites after aging is also increased significantly with GO modified sizing agents. PMID:26682416

  3. Studies on non-oxide coating on carbon fibers using plasma enhanced chemical vapor deposition technique

    NASA Astrophysics Data System (ADS)

    Patel, R. H.; Sharma, S.; Prajapati, K. K.; Vyas, M. M.; Batra, N. M.

    2016-05-01

    A new way of improving the oxidative behavior of carbon fibers coated with SiC through Plasma Enhanced Chemical Vapor Deposition technique. The complete study includes coating of SiC on glass slab and Stainless steel specimen as a starting test subjects but the major focus was to increase the oxidation temperature of carbon fibers by PECVD technique. This method uses relatively lower substrate temperature and guarantees better stoichiometry than other coating methods and hence the substrate shows higher resistance towards mechanical and thermal stresses along with increase in oxidation temperature.

  4. Application of diffusion barriers to the refractory fibers of tungsten, columbium, carbon and aluminum oxide

    NASA Technical Reports Server (NTRS)

    Douglas, F. C.; Paradis, E. L.; Veltri, R. D.

    1973-01-01

    A radio frequency powered ion-plating system was used to plate protective layers of refractory oxides and carbide onto high strength fiber substrates. Subsequent overplating of these combinations with nickel and titanium was made to determine the effectiveness of such barrier layers in preventing diffusion of the overcoat metal into the fibers with consequent loss of fiber strength. Four substrates, five coatings, and two metal matrix materials were employed for a total of forty material combinations. The substrates were tungsten, niobium, NASA-Hough carbon, and Tyco sapphire. The diffusion-barrier coatings were aluminum oxide, yttrium oxide, titanium carbide, tungsten carbide with 14% cobalt addition, and zirconium carbide. The metal matrix materials were IN 600 nickel and Ti 6/4 titanium. Adhesion of the coatings to all substrates was good except for the NASA-Hough carbon, where flaking off of the oxide coatings in particular was observed.

  5. Fiber

    MedlinePlus

    ... it can help with weight control. Fiber aids digestion and helps prevent constipation . It is sometimes used ... fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in ...

  6. Oxide Fiber Cathode Materials for Rechargeable Lithium Cells

    NASA Technical Reports Server (NTRS)

    Rice, Catherine E.; Welker, Mark F.

    2008-01-01

    LiCoO2 and LiNiO2 fibers have been investigated as alternatives to LiCoO2 and LiNiO2 powders used as lithium-intercalation compounds in cathodes of rechargeable lithium-ion electrochemical cells. In making such a cathode, LiCoO2 or LiNiO2 powder is mixed with a binder [e.g., poly(vinylidene fluoride)] and an electrically conductive additive (usually carbon) and the mixture is pressed to form a disk. The binder and conductive additive contribute weight and volume, reducing the specific energy and energy density, respectively. In contrast, LiCoO2 or LiNiO2 fibers can be pressed and sintered to form a cathode, without need for a binder or a conductive additive. The inter-grain contacts of the fibers are stronger and have fewer defects than do those of powder particles. These characteristics translate to increased flexibility and greater resilience on cycling and, consequently, to reduced loss of capacity from cycle to cycle. Moreover, in comparison with a powder-based cathode, a fiber-based cathode is expected to exhibit significantly greater ionic and electronic conduction along the axes of the fibers. Results of preliminary charge/discharge-cycling tests suggest that energy densities of LiCoO2- and LiNiO2-fiber cathodes are approximately double those of the corresponding powder-based cathodes.

  7. A novel structure photonic crystal fiber based on bismuth-oxide for optical parametric amplification

    NASA Astrophysics Data System (ADS)

    Jin, Cang; Yuan, Jinhui; Yu, Chongxiu

    2010-11-01

    The heavy metal oxide glasses containing bismuth such as bismuth sesquioxide show unique high refractive index. In addition, the bismuth-oxide based glass does not include toxic elements such as Pb, As, Se, Te, and exhibits well chemical, mechanical and thermal stability. Hence, it is used to fabricate high nonlinear fiber for nonlinear optical application. Although the bismuth-oxide based high nonlinear fiber can be fusion-spliced to conventional silica fibers and have above advantages, yet it suffers from large group velocity dispersion because of material chromatic dispersion which restricts its utility. In regard to this, the micro-structure was introduced to adjust the dispersion of bismuth-oxide high nonlinear fiber in the 1550nm wave-band. In this paper, a hexagonal solid-core micro-structure is developed to balance its dispersion and nonlinearity. Our simulation and calculation results show that the bismuth-oxide based photonic crystal fiber has near zero dispersion around 1550nm where the optical parametric amplification suitable wavelength is. Its dispersion slop in the communication wavelength range is also relatively flat. Moreover, both nonlinear coefficient and model filed distribution were simulated, respectively.

  8. Oxidative Stress in Intracerebral Hemorrhage: Sources, Mechanisms, and Therapeutic Targets

    PubMed Central

    Hu, Xin; Tao, Chuanyuan; Gan, Qi; Zheng, Jun; Li, Hao; You, Chao

    2016-01-01

    Intracerebral hemorrhage (ICH) is associated with the highest mortality and morbidity despite only constituting approximately 10–15% of all strokes. Complex underlying mechanisms consisting of cytotoxic, excitotoxic, and inflammatory effects of intraparenchymal blood are responsible for its highly damaging effects. Oxidative stress (OS) also plays an important role in brain injury after ICH but attracts less attention than other factors. Increasing evidence has demonstrated that the metabolite axis of hemoglobin-heme-iron is the key contributor to oxidative brain damage after ICH, although other factors, such as neuroinflammation and prooxidases, are involved. This review will discuss the sources, possible molecular mechanisms, and potential therapeutic targets of OS in ICH. PMID:26843907

  9. Proposal of Liquid Cannon Target Driven by Fiber Laser for Micro-Thruster in Satellite

    NASA Astrophysics Data System (ADS)

    Yabe, Takashi; Ohzono, Hirokazu; Ohkubo, Tomomasa; Baasandash, Choijil; Yamaguchi, Masashi; Oku, Takehiro; Taniguchi, Kazumoto; Miyazaki, Sho; Akoh, Ryosuke; Ogata, Yoichi; Rosenberg, Benjamin; Yoshida, Minoru

    2004-03-01

    We propose a new concept controlling a satellite by a fiber laser loaded in it and demonstrated the acceleration of pendulum with 7kW/2n and 2kHz fiber laser, and measured the Cm of 16Ns/MJ corresponding to the scaling of YAG laser. This laser can be easily bundled to generate much larger power. For more efficient acceleration, we propose ``metal-free water cannon target'', the new concept of propulsion using only water. The momentum coupling coefficient of 2500[Ns/MJ] was achieved with vacuum pump oil instead of water, and we succeeded in controlling the driving direction by the system based on the new concept. This can be used for thrusting a satellite and controlling its posture in combination with fiber lasers.

  10. Proposal of Liquid Cannon Target Driven by Fiber Laser for Micro-Thruster in Satellite

    SciTech Connect

    Yabe, Takashi; Ohzono, Hirokazu; Ohkubo, Tomomasa; Baasandash, Choijil; Yamaguchi, Masashi; Oku, Takehiro; Taniguchi, Kazumoto; Miyazaki, Sho; Akoh, Ryosuke; Ogata, Yoichi; Rosenberg, Benjamin; Yoshida, Minoru

    2004-03-30

    We propose a new concept controlling a satellite by a fiber laser loaded in it and demonstrated the acceleration of pendulum with 7kW/2n and 2kHz fiber laser, and measured the Cm of 16Ns/MJ corresponding to the scaling of YAG laser. This laser can be easily bundled to generate much larger power. For more efficient acceleration, we propose 'metal-free water cannon target', the new concept of propulsion using only water. The momentum coupling coefficient of 2500[Ns/MJ] was achieved with vacuum pump oil instead of water, and we succeeded in controlling the driving direction by the system based on the new concept. This can be used for thrusting a satellite and controlling its posture in combination with fiber lasers.

  11. Carbon aerogel composites prepared by ambient drying and using oxidized polyacrylonitrile fibers as reinforcements.

    PubMed

    Feng, Junzong; Zhang, Changrui; Feng, Jian; Jiang, Yonggang; Zhao, Nan

    2011-12-01

    Carbon fiber-reinforced carbon aerogel composites (C/CAs) for thermal insulators were prepared by copyrolysis of resorcinol-formaldehyde (RF) aerogels reinforced by oxidized polyacrylonitrile (PAN) fiber felts. The RF aerogel composites were obtained by impregnating PAN fiber felts with RF sols, then aging, ethanol exchanging, and drying at ambient pressure. Upon carbonization, the PAN fibers shrink with the RF aerogels, thus reducing the difference of shrinkage rates between the fiber reinforcements and the aerogel matrices, and resulting in C/CAs without any obvious cracks. The three point bend strength of the C/CAs is 7.1 ± 1.7 MPa, and the thermal conductivity is 0.328 W m(-1) K(-1) at 300 °C in air. These composites can be used as high-temperature thermal insulators (in inert atmospheres or vacuum) or supports for phase change materials in thermal protection system. PMID:22047011

  12. Growth of sapphire and oxide eutectic fibers by the EFG technique

    NASA Astrophysics Data System (ADS)

    Kurlov, V. N.; Stryukov, D. O.; Shikunova, I. A.

    2016-01-01

    Single-crystal sapphire and oxide binary (Al2O3-Y3Al5O12, Al2O3-Er3Al5O12, Al2O3- GdAlO3) and ternary (Al2O3-ZrO2(Y2O3)) eutectic fibers of 150-300 µm in diameters were grown by the edge-defined film-fed growth (EFG) technique. Microstructure and some properties of fibers were investigated.

  13. Development of a core sheath process for production of oxide fibers

    NASA Technical Reports Server (NTRS)

    Freske, S.

    1972-01-01

    Improvements were sought in an oxide fiber of a core sheath configuration intended for structural applications at 2000 F (1093 C). Discontinuities in the core were eliminated by using core materials other than pure alumina, and continuous core sheath fibers were produced. In the case of some core materials, the continuous sections were sufficiently long for applications in short fiber composites. Creep at 2000 F (1093 C) was found to be due, in most cases, to breaks in the core, allowing the glass sheath to creep. Evidence was obtained indicating that a closer match between the thermal expansion coefficient of the sheath and the core would greatly improve the strength.

  14. Cell Labeling and Targeting with Superparamagnetic Iron Oxide Nanoparticles.

    PubMed

    Tefft, Brandon J; Uthamaraj, Susheil; Harburn, J Jonathan; Klabusay, Martin; Dragomir-Daescu, Dan; Sandhu, Gurpreet S

    2015-01-01

    Targeted delivery of cells and therapeutic agents would benefit a wide range of biomedical applications by concentrating the therapeutic effect at the target site while minimizing deleterious effects to off-target sites. Magnetic cell targeting is an efficient, safe, and straightforward delivery technique. Superparamagnetic iron oxide nanoparticles (SPION) are biodegradable, biocompatible, and can be endocytosed into cells to render them responsive to magnetic fields. The synthesis process involves creating magnetite (Fe3O4) nanoparticles followed by high-speed emulsification to form a poly(lactic-co-glycolic acid) (PLGA) coating. The PLGA-magnetite SPIONs are approximately 120 nm in diameter including the approximately 10 nm diameter magnetite core. When placed in culture medium, SPIONs are naturally endocytosed by cells and stored as small clusters within cytoplasmic endosomes. These particles impart sufficient magnetic mass to the cells to allow for targeting within magnetic fields. Numerous cell sorting and targeting applications are enabled by rendering various cell types responsive to magnetic fields. SPIONs have a variety of other biomedical applications as well including use as a medical imaging contrast agent, targeted drug or gene delivery, diagnostic assays, and generation of local hyperthermia for tumor therapy or tissue soldering. PMID:26554870

  15. Targeting Oxidative Stress in Central Nervous System Disorders.

    PubMed

    Patel, Manisha

    2016-09-01

    There is widespread recognition that reactive oxygen species (ROS) play key roles in normal brain function and pathology in the context of neurological disease. Oxidative stress continues to be a key therapeutic target for neurological diseases. In developing antioxidant therapies for neurological disease, special attention should be given to the brain's unique vulnerability to oxidative insults and its architecture. Consideration of antioxidant therapy should be guided by a strong rationale for oxidative stress in a given neurological disease. This review provides an overview of processes that can guide the development of antioxidant therapies in neurological diseases, such as knowledge of basic redox mechanisms, unique features of brain pathophysiology, mechanisms and classes of antioxidants, and desirable properties of drug candidates. PMID:27491897

  16. Carbon oxidation in ceramic composites and the evaluation of interfacial sealing for oxidation resistant fiber-reinforced composite systems

    NASA Astrophysics Data System (ADS)

    Glime, William Harrison, III

    1997-11-01

    Carbon offers desirable properties as a fiber-matrix interphase material in ceramic matrix composites (CMC's), but oxidation of carbon at temperatures above 500sp°C has limited its utility. In an effort to better understand the kinetics associated with carbon oxidation pertaining to CMC applications, the origin of non-planar morphologies observed in the reaction front of carbon fibers and interphases receding into a ceramic matrix in the temperature range of 700sp°C to 1000sp°C was analyzed. A numerical simulation based on the finite difference method is utilized to evaluate the parameters which govern the morphology of the receding carbon reaction front. The study indicates that the morphology of the reaction front contains information regarding the interplay between oxidation behavior and microstructural features of the carbon. Carbon oxidation was found to obey "weak-link" behavior, that is, a sub-component which is more susceptible to oxidation governs the recession kinetics. The implications of weak link oxidation to preservation of a carbon interphase in a ceramic composite are discussed. Interrupted interphases have demonstrated the ability to confine oxidation of a carbon interphase to a localized region adjacent to a matrix crack. Commercial SiC mono-filaments (SCS-6, Textron Specialty Materials) were modified with a laser to produce fibers with discontinuous carbon coatings that were used in experiments to study mechanical properties. The laser-scribed fibers were tested in isolation, used in single-fiber microcomposites, or incorporated into small bulk composite specimens using a powder processing route to produce the matrix. The mechanical performance of the various types of specimens prepared using the laser scribing technique is presented and these results are used in a simulation of ultimate composite properties. The effect of fiber matrix fusion, by direct bonding or through a reaction product which seals the interface, was investigated with

  17. Highly tunable interfacial adhesion of glass fiber by hybrid multilayers of graphene oxide and aramid nanofiber.

    PubMed

    Park, Byeongho; Lee, Wonoh; Lee, Eunhee; Min, Sa Hoon; Kim, Byeong-Su

    2015-02-11

    The performance of fiber-reinforced composites is governed not only by the nature of each individual component comprising the composite but also by the interfacial properties between the fiber and the matrix. We present a novel layer-by-layer (LbL) assembly for the surface modification of a glass fiber to enhance the interfacial properties between the glass fiber and the epoxy matrix. Solution-processable graphene oxide (GO) and an aramid nanofiber (ANF) were employed as active components for the LbL assembly onto the glass fiber, owing to their abundant functional groups and mechanical properties. We found that the interfacial properties of the glass fibers uniformly coated with GO and ANF multilayers, such as surface free energy and interfacial shear strength, were improved by 23.6% and 39.2%, respectively, compared with those of the bare glass fiber. In addition, the interfacial adhesion interactions between the glass fiber and the epoxy matrix were highly tunable simply by changing the composition and the architecture of layers, taking advantage of the versatility of the LbL assembly. PMID:25599567

  18. Skeletal muscle fiber type: using insights from muscle developmental biology to dissect targets for susceptibility and resistance to muscle disease.

    PubMed

    Talbot, Jared; Maves, Lisa

    2016-07-01

    Skeletal muscle fibers are classified into fiber types, in particular, slow twitch versus fast twitch. Muscle fiber types are generally defined by the particular myosin heavy chain isoforms that they express, but many other components contribute to a fiber's physiological characteristics. Skeletal muscle fiber type can have a profound impact on muscle diseases, including certain muscular dystrophies and sarcopenia, the aging-induced loss of muscle mass and strength. These findings suggest that some muscle diseases may be treated by shifting fiber type characteristics either from slow to fast, or fast to slow phenotypes, depending on the disease. Recent studies have begun to address which components of muscle fiber types mediate their susceptibility or resistance to muscle disease. However, for many diseases it remains largely unclear why certain fiber types are affected. A substantial body of work has revealed molecular pathways that regulate muscle fiber type plasticity and early developmental muscle fiber identity. For instance, recent studies have revealed many factors that regulate muscle fiber type through modulating the activity of the muscle regulatory transcription factor MYOD1. Future studies of muscle fiber type development in animal models will continue to enhance our understanding of factors and pathways that may provide therapeutic targets to treat muscle diseases. WIREs Dev Biol 2016, 5:518-534. doi: 10.1002/wdev.230 For further resources related to this article, please visit the WIREs website. PMID:27199166

  19. Targeted illumination and tracking using optical fiber probe for optogenetics application

    NASA Astrophysics Data System (ADS)

    Shinde, Anant; Perinchery, Sandeep M.; Matham, Murukeshan V.

    2016-03-01

    There was a renewed interest, during the recent years, in the imaging and tracking of targeted cells or organelles for a variety of biomedical and lab-on a chip applications that include particles movement. However, nonspecific illumination during tracking can have adverse effects such as heating, reduced image contrast and photo bleaching. In fact, current available tracking and imaging systems are unable to selectively illuminate the particle being tracked. To fill this void, we have developed a fiber optics based probe system incorporating a spatial light modulator (SLM) and an imaging fiber bundle for selective illumination on the targeted particle. A GRIN lens is attached at the distal endface of the image fiber bundle for optimised illumination and collection. A tracking algorithm is developed in order to enable controlled illumination through SLM to target the illumination point or location in accordance with the particle movement and size variation. Further with this probe, particles can be illuminated with light pulses of controllable duty cycle and frequency. The proposed methodology and developed probe have good significance and expected to find potential applications areas such as optogenetics, cell signalling studies, and lab-on a chip systems.

  20. Multiwavelength L-band fiber laser with bismuth-oxide EDF and photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ramzia Salem, A. M.; Al-Mansoori, M. H.; Hizam, H.; Mohd Noor, S. B.; Abu Bakar, M. H.; Mahdi, M. A.

    2011-05-01

    A multiwavelength laser comb using a bismuth-based erbium-doped fiber and 50 m photonic crystal fiber is demonstrated in a ring cavity configuration. The fiber laser is solely pumped by a single 1455 nm Raman pump laser to exploit its higher power delivery compared to that of a single-mode laser diode pump. At 264 mW Raman pump power and 1 mW Brillouin pump power, 38 output channels in the L-band have been realized with an optical signal-to-noise ratio above 15 dB and a Stokes line spacing of 0.08 nm. The laser exhibits a tuning range of 12 nm and produces stable Stokes lines across the tuning range between Brillouin pump wavelengths of 1603 nm and 1615 nm.

  1. Innovative fabrication of the flower-like nanocomposite coating on a nitinol fiber through Fenton's oxidation for selective and sensitive solid-phase microextraction.

    PubMed

    Zhang, Min; Zhen, Qi; Wang, Huiju; Guo, Mei; Zhou, Shanshan; Wang, Xuemei; Du, Xinzhen

    2016-09-01

    A novel flower-like nanostructure was successfully in situ fabricated on the surface of nitinol wire through Fenton's oxidation for the first time. It was found that the densely immobilized coating on the surface of the nitinol fiber was composed of nickel and titanium oxide nanocomposite (NiO/TiO2NC). The NiO/TiO2NC coated fiber was used to extract aromatic compounds coupled with high performance liquid chromatography (HPLC) with UV detection and exhibited excellent extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) with larger delocalized π-system among the studied analytes. Important factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0.05 to 500μgL(-1) with correlation coefficients of R(2)≥0.999, and the lowest limit of detection of 0.006μgL(-1) was achieved for benzo[a]pyrene. Furthermore, the intra-day and inter-day precisions for the single fiber varied from 4.69% to 5.97% and from 5.28% to 6.32% for five replicates of PAHs at the spiking level of 50μgL(-1), respectively. The fiber-to-fiber precision for five fibers prepared in different batches ranged from 6.19% to 8.35%. The developed method was successfully applied to concentration and determination of target PAHs from real environmental water samples. Moreover, this novel nitinol-based fiber exhibited long lifespan. Therefore, the proposed fiber can be used as a promising candidate for a conventional fused silica-based fiber in SPME. PMID:27343598

  2. Thermo-oxidative stability studies of Celion 6000/PMR-15 unidirectional composites, PMR-15, and Celion 6000 fiber

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.; Nowak, Gregory

    1988-01-01

    Experimental results on the influence of the thermooxidative resistance characteristics of the fiber and matrix resin on the thermal stability of isothermally aged Celion 6000/PMR-15 matrix resin composites are presented. SEM studies reveal that extreme oxidative erosion of the graphite fiber occurs at elevated temperatures in the presence of the polyimide matrix. The activation energy of oxidation of the composite was shown to be greater than those of the fiber and the matrix resin.

  3. Dissolution of Neptunium Oxide in Unirradiated Mark 53 Targets

    SciTech Connect

    Rudisill, T.S.

    2002-12-06

    Nine unirradiated Mark 53 targets currently stored at the K-Reactor must be dissolved to allow recovery of the neptunium content. The Mark 53 targets are an aluminum clad, neptunium oxide (NpO2)/aluminum metal cermet used for the production of plutonium-238. The targets will be dissolved in H-Canyon and blended with solutions generated from routine fuel dissolutions for purification by solvent extraction. The increased neptunium concentration should not have a significant effect on the neptunium decontamination factor achieved by the 1st cycle of solvent extraction; however, the neptunium content of the uranium product (1CU) will likely increase in proportion to the increase in the neptunium feed concentration. The recovered neptunium will be combined with the existing inventory of neptunium solution currently stored in H-Canyon. The combined inventory will undergo subsequent purification and conversion to an oxide for shipment to the Oak Ridge National Laboratory where plutonium- 238 will be manufactured using the High Flux Isotope Reactor.

  4. Oxidation of activated carbon fibers: Effect on pore size, surface chemistry, and adsorption properties

    SciTech Connect

    Mangun, C.L.; Benak, K.R.; Daley, M.A.; Economy, J.

    1999-12-01

    Activated carbon fibers (ACFs) were oxidized using both aqueous and nonaqueous treatments. As much as 29 wt% oxygen can be incorporated onto the pore surface in the form of phenolic hydroxyl, quinine, and carboxylic acid groups. The effect of oxidation on the pore size, pore volume, and the pore surface chemistry was thoroughly examined. The average micropore size is typically affected very little by aqueous oxidation while the micropore volume and surface area decreases with such a treatment. In contrast, the micropore size and micropore volume both increase with oxidation in air. Oxidation of the fibers produces surface chemistries in the pore that provide for enhanced adsorption of basic (ammonia) and polar (acetone) molecules at ambient and nonambient temperatures. The adsorption capacity of the oxidized fibers for acetone is modestly better than the untreated ACFs while the adsorption capacity for ammonia can increase up to 30 times compared to untreated ACFs. The pore surface chemical makeup was analyzed using elemental analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and X-ray photoelectron spectroscopy (XPS).

  5. Niacin supplementation increases the number of oxidative type I fibers in skeletal muscle of growing pigs

    PubMed Central

    2013-01-01

    Background A recent study showed that niacin supplementation counteracts the obesity-induced muscle fiber switching from oxidative type I to glycolytic type II and increases the number of type I fibers in skeletal muscle of obese Zucker rats. These effects were likely mediated by the induction of key regulators of fiber transition, PGC-1α and PGC-1β, leading to muscle fiber switching and up-regulation of genes involved in mitochondrial fatty acid import and oxidation, citrate cycle, oxidative phosphorylation, mitochondrial biogenesis. The aim of the present study was to investigate whether niacin supplementation causes type II to type I muscle and changes the metabolic phenotype of skeletal muscles in growing pigs. Results 25 male, 11 wk old crossbred pigs (Danzucht x Pietrain) with an average body weight of 32.8 ± 1.3 (mean ± SD) kg were randomly allocated to two groups of 12 (control group) and 13 pigs (niacin group) which were fed either a control diet or a diet supplemented with 750 mg niacin/kg diet. After 3 wk, the percentage number of type I fibers in three different muscles (M. longissismus dorsi, M. quadriceps femoris, M. gastrocnemius) was greater in the niacin group and the percentage number of type II fibers was lower in the niacin group than in the control group (P < 0.05). The mRNA levels of PGC-1β and genes involved in mitochondrial fatty acid catabolism (CACT, FATP1, OCTN2), citrate cycle (SDHA), oxidative phosphorylation (COX4/1, COX6A1), and thermogenesis (UCP3) in M. longissimus dorsi were greater in the niacin group than in the control group (P < 0.05). Conclusions The study demonstrates that niacin supplementation induces type II to type I muscle fiber switching, and thereby an oxidative metabolic phenotype of skeletal muscle in pigs. Given that oxidative muscle types tend to develop dark, firm and dry pork in response to intense physical activity and/or high psychological stress levels preslaughter, a niacin

  6. Thermo-oxidative stability of graphite fiber/PMR-15 polyimide composites at 350 deg C

    NASA Technical Reports Server (NTRS)

    Scola, D. A.

    1985-01-01

    A series of graphite fiber/PMR-15 polyimide composites were subjected to isothermal aging at 350 C in flowing air (100 cc/min and 1000 cc/min) over a 520 hr time period. The graphite fibers were analyzed by ISS/SIMS techniques before composite fabrication. Fibers exposed at the surface of the composite due to the isothermal aging process were also analyzed by the ISS/SIMS method. Component and composite weight less studies were also conducted for similarly exposed materials. Optical micrograph investigations of composites to follow the progress of the thermo-oxidative process were also conducted. Flexural and interlaminar shear strengths of the imaged and aged composites were measured. The relationship of component and composite properties as they relate to the thermo-oxidative behavior of the materials was discussed.

  7. Adrenaline and noradrenaline: protectors against oxidative stress or molecular targets?

    PubMed

    Álvarez-Diduk, Ruslán; Galano, Annia

    2015-02-26

    Density functional theory was used to investigate the potential role of neurotransmitters adrenaline and noradrenaline regarding oxidative stress. It is predicted that they can be efficient as free radical scavengers both in lipid and aqueous media, with the main reaction mechanism being the hydrogen transfer and the sequential proton loss electron transfer, respectively. Despite the polarity of the environment, adrenaline and noradrenaline react with (•)OOH faster than Trolox, which suggests that they are better peroxyl radical scavengers than the reference compound. Both catecholamines are also proposed to be capable of efficiently inhibiting the oxidative stress induced by copper(II)-ascorbate mixtures, and the (•)OH production via Haber-Weiss reaction, albeit the effects on the later are only partial. They exert such beneficial effects by sequestering Cu(II) ions. In summary, these catecholamines can be capable of reducing oxidative stress, by scavenging free radicals and by sequestering metal ions. However, at the same time they might lose their functions in the process due to the associated structural modifications. Consequently, adrenaline and noradrenaline can be considered as both protectors and molecular targets of oxidative stress. Fortunately, under the proper conditions, both catecholamines can be regenerated to their original form so their functions are restored. PMID:25646569

  8. Construction and performance of a plastic scintillating fiber target for a rare kaon decay experiment

    SciTech Connect

    Frank, J.S.; Strand, R.C.

    1988-01-01

    A K/sup +/ stopping target consisting of 2269 plastic fibers, 2 mm diameter and 3.12 m long has been installed in an experiment searching for the rare decay K/sup +/ to ..pi nu../bar nu/ at Brookhaven National Laboratory. The fibers are bundled onto 379 photomultiplier tube and base assemblies with single photoelectron resolution. After routing to the counting room, the signals are amplified and then distributed to TDC's and high-pass filter circuits that provide signals to ADC's and to fan-ins that provide a target energy-sum pulse used in the fast triggering logic. A minimum ionizing particle 3 m from the photomultiplier yields 1 photoelectron/mm path. The target provides transverse spatial resolution of 4 mm (FWHM) for the vertex of the K/sup +/ decay and 2 ns timing resolution (FWHM) on the difference between the K/sup +/ stop and the subsequent decay. Details of the target construction and operating performance are provided. 4 refs., 7 figs.

  9. Oxidative stress and abdominal aortic aneurysm: potential treatment targets.

    PubMed

    Emeto, Theophilus I; Moxon, Joseph V; Au, Minnie; Golledge, Jonathan

    2016-03-01

    Abdominal aortic aneurysm (AAA) is a significant cause of mortality in older adults. A key mechanism implicated in AAA pathogenesis is inflammation and the associated production of reactive oxygen species (ROS) and oxidative stress. These have been suggested to promote degradation of the extracellular matrix (ECM) and vascular smooth muscle apoptosis. Experimental and human association studies suggest that ROS can be favourably modified to limit AAA formation and progression. In the present review, we discuss mechanisms potentially linking ROS to AAA pathogenesis and highlight potential treatment strategies targeting ROS. Currently, none of these strategies has been shown to be effective in clinical practice. PMID:26814202

  10. Fiber-Optic SPR Immunosensors Tailored To Target Epithelial Cells through Membrane Receptors.

    PubMed

    Malachovská, Viera; Ribaut, Clotilde; Voisin, Valérie; Surin, Mathieu; Leclère, Philippe; Wattiez, Ruddy; Caucheteur, Christophe

    2015-06-16

    We report, for the first time, the use of a surface plasmon resonance (SPR) fiber-optic immunosensor for selective cellular detection through membrane protein targeting. The sensor architecture lies on gold-coated tilted fiber Bragg gratings (Au-coated TFBGs) photoimprinted in the fiber core via a laser technique. TFBGs operate in the near-infrared wavelength range at ∼1550 nm, yielding optical and SPR sensing characteristics that are advantageous for the analyses of cellular bindings and technical compatibility with relatively low-cost telecommunication-grade measurement devices. In this work, we take consider their numerous assets to figure out their ability to selectively detect intact epithelial cells as analytes in cell suspensions in the range of 2-5 × 10(6) cells mL(-1). For this, the probe was first thermally annealed to ensure a strong adhesion of the metallic coating to the fiber surface. Its surface was then functionalized with specific monoclonal antibodies via alkanethiol self-assembled monolayers (SAMs) against extracellular domain of epidermal growth factor receptors (EGFRs) and characterized by peak force tapping atomic force microscopy. A differential diagnosis has been demonstrated between two model systems. The developed immunosensors were able to monitor, in real time, the specific attachment of single intact cells in concentrations from 3 × 10(6) cells mL(-1). Such results confirm that the developed probe fits the lab-on-fiber technology and has the potential to be used as a disposable device for in situ and real-time clinical diagnosis. PMID:25962700

  11. The effects of pre-oxidation heating rate on bio-based carbon fibers and its surface repair

    NASA Astrophysics Data System (ADS)

    Wu, H.; Cheng, L. F.; Fan, S. W.; Yuan, X. W.; Bhattacharyya, D.

    2015-03-01

    Low-cost carbon fibers (CFs) are fabricated from jute fibers after pre-oxidation, carbonization and surface repair. This paper investigates the effects of pre-oxidation heating rate on jute fibers, and explores a repair method for surface defects of CFs in C/C composite. The results show the reaction mechanism of jute fibers in air is not changed at higher pre-oxidation heating rates while a low heating rate is still required as the oxidation of jute fibers cannot be fully achieved under rapid heating. The tensile strength of CFs increases after repair with a 5% phenolic resin solution. Jute-based CFs play a positive role in C/C composite performance through crack bridging and deflection.

  12. Single Crystal Fibers of Yttria-Stabilized Cubic Zirconia with Ternary Oxide Additions

    NASA Technical Reports Server (NTRS)

    Ritzert, F. J.; Yun, H. M.; Miner, R. V.

    1997-01-01

    Single crystal fibers of yttria (Y2O3)-stabilized cubic zirconia, (ZrO2) with ternary oxide additions were grown using the laser float zone fiber processing technique. Ternary additions to the ZrO2-Y2O3 binary system were studied aimed at increasing strength while maintaining the high coefficient of thermal expansion of the binary system. Statistical methods aided in identifying the most promising ternary oxide candidate (Ta2O5, Sc2O3, and HfO2) and optimum composition. The yttria, range investigated was 14 to 24 mol % and the ternary oxide component ranged from 1 to 5 mol %. Hafnium oxide was the most promising ternary oxide component based on 816 C tensile strength results and ease of fabrication. The optimum composition for development was 81 ZrO2-14 Y203-5 HfO2 based upon the same elevated temperature strength tests. Preliminary results indicate process improvements could improve the fiber performance. We also investigated the effect of crystal orientation on strength.

  13. Destruction of monocrystalline silicon with nanosecond pulsed fiber laser accompanied by the oxidation of ablation microparticles

    NASA Astrophysics Data System (ADS)

    Veiko, V. P.; Skvortsov, A. M.; Huynh, C. T.; Petrov, A. A.

    2013-11-01

    In this work, we report an observation of process of local destruction monocrystalline silicon with a scanning beam irradiation of pulse ytterbium fiber laser with a wavelength λ= 1062 nm, accompanied by the oxidation of ablation microparticles. It is shown that depending on the power density of irradiation was observed a large scatter size of the microparticles. From a certain average power density is observed beginning oxidation particulate emitted from the surface of the irradiated area. By varying the parameters of the laser beam such as scanning speed, pulse repetition rate, overlap of laser spot, radiation dose can be achieved almost complete oxidation of all formed during the ablation of microparticles.

  14. Sub-micrometer sized yttrium oxide fibers prepared through hydrothermal reaction

    SciTech Connect

    Li, Nan; Yanagisawa, Kazumichi

    2011-03-15

    Research highlights: {yields} Y{sub 2}O{sub 3} fibers were synthesized by hydrothermal reaction followed by calcination. {yields} Y(OH){sub x}Cl{sub 3-x}.yH{sub 2}O was received from hydrothermal reaction. {yields} Y{sub 2}O{sub 3} fibers showed outstanding high-temperature stability. -- Abstract: Yttrium oxide fibers have been synthesized via hydrothermal reaction and subsequent thermal treatment using yttrium chloride as precursor. The products before and after the thermal treatment were characterized by powder X-ray diffractions (XRD), scanning electron microscopy (SEM), ion-chromatograph analysis, and thermogravimetry and differential thermal analysis (TG-DTA). The fiber diameter ranged from 100 to 300 nm, while the length was up to tens of microns. It was found that the chemical composition and morphology of the products were closely related to the pH value of reaction solution, and fibrous products could be obtained at pH 9.5-10.25. These oxide fibers exhibited outstanding high-temperature stability, which maintained their morphology at temperature up to 1400 {sup o}C.

  15. Hybrid Silk Fibers Dry-Spun from Regenerated Silk Fibroin/Graphene Oxide Aqueous Solutions.

    PubMed

    Zhang, Chao; Zhang, Yaopeng; Shao, Huili; Hu, Xuechao

    2016-02-10

    Regenerated silk fibroin (RSF)/graphene oxide (GO) hybrid silk fibers were dry-spun from a mixed dope of GO suspension and RSF aqueous solution. It was observed that the presence of GO greatly affect the viscosity of RSF solution. The RSF/GO hybrid fibers showed from FTIR result lower β-sheet content compared to that of pure RSF fibers. The result of synchrotron radiation wide-angle X-ray diffraction showed that the addition of GO confined the crystallization of silk fibroin (SF) leading to the decrease of crystallinity, smaller crystallite size, and new formation of interphase zones in the artificial silks. Synchrotron radiation small-angle X-ray scattering also proved that GO sheets in the hybrid silks and blended solutions were coated with a certain thickness of interphase zones due to the complex interaction between the two components. A low addition of GO, together with the mesophase zones formed between GO and RSF, enhanced the mechanical properties of hybrid fibers. The highest breaking stress of the hybrid fibers reached 435.5 ± 71.6 MPa, 23% improvement in comparison to that of degummed silk and 72% larger than that of pure RSF silk fiber. The hybrid RSF/GO materials with good biocompatibility and enhanced mechanical properties may have potential applications in tissue engineering, bioelectronic devices, or energy storage. PMID:26784289

  16. Vector rectangular-shape laser based on reduced graphene oxide interacting with a long fiber taper.

    PubMed

    Gao, Lei; Zhu, Tao; Huang, Wei; Zeng, Jing

    2014-10-01

    A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where nonlinearity is enhanced due to a large evanescent-field-interacting length and strong field confinement of an 8 mm fiber taper with a waist diameter of 4 μm. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz shows fast polarization switching in two orthogonal polarization directions, and temporal and spectral characteristics are investigated. PMID:25322232

  17. Modification of surface oxide layers of titanium targets for increasing lifetime of neutron tubes

    SciTech Connect

    Zakharov, A. M. Dvoichenkova, O. A.; Evsin, A. E.

    2015-12-15

    The peculiarities of interaction of hydrogen ions with a titanium target and its surface oxide layer were studied. Two ways of modification of the surface oxide layers of titanium targets for increasing the lifetime of neutron tubes were proposed: (1) deposition of an yttrium oxide barrier layer on the target surface; (2) implementation of neutron tube work regime in which the target is irradiated with ions with energies lower than 1000 eV between high-energy ion irradiation pulses.

  18. Modification of surface oxide layers of titanium targets for increasing lifetime of neutron tubes

    NASA Astrophysics Data System (ADS)

    Zakharov, A. M.; Dvoichenkova, O. A.; Evsin, A. E.

    2015-12-01

    The peculiarities of interaction of hydrogen ions with a titanium target and its surface oxide layer were studied. Two ways of modification of the surface oxide layers of titanium targets for increasing the lifetime of neutron tubes were proposed: (1) deposition of an yttrium oxide barrier layer on the target surface; (2) implementation of neutron tube work regime in which the target is irradiated with ions with energies lower than 1000 eV between high-energy ion irradiation pulses.

  19. Facile synthesis of graphite-reduced graphite oxide core-sheath fiber via direct exfoliation of carbon fiber for supercapacitor application.

    PubMed

    Ji, Qinghua; Zhao, Xu; Liu, Huijuan; Guo, Lin; Qu, Jiuhui

    2014-06-25

    A graphite-reduced graphite oxide (rGO) core-sheath structured fiber was synthesized through chemical exfoliation of graphitic carbon fiber. The graphitic carbon fiber was oxidized to form a graphite-graphite oxide core-sheath fiber and followed by thermal exfoliation to form a graphite-rGO core-sheath fiber. The core-sheath fiber with a three-dimensionally (3D) structured rGO sheath possesses a high surface area and pore size around 5.5 nm. A two-electrode supercapacitor constructed with this core-sheath fiber-based paper exhibited a high specific capacitance (140 F g(-1) at a current density of 1 A g(-1)), high power density of 45 kW/kg, and good cycling stability (10% capacity loss after 3000 cycles). The surface area normalized capacitance reached as high as 59.4 μF cm(-2), indicating the effective use of surface area. The low equivalent series resistance value of 0.45 ohm in the Nyquist plot indicates an extremely small resistance between the graphite core and rGO sheet sheath. The hierarchical three-dimensional structure enables one to maximize the advantages of both graphite and rGO sheets. The 3D-structured rGO sheets sheath with regular pore structure is favorable for ion diffusion due to its interconnected porous system, while the graphite core provides an electron transport pathway with high conductivity. PMID:24820530

  20. Sliding durability of two carbide-oxide candidate high temperature fiber seal materials in air to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Steinetz, Bruce M.

    1992-01-01

    A test program to determine the friction and wear properties of two complex carbide oxide ceramic fibers for high temperature sliding seal applications is described. The fibers are based on Si, C, O, and Ti or Si, C, N, and O ceramic systems. Pin on disk tests using ceramic fiber covered pins and Inconel 718 disks, were conducted in air from 25 to 900 C to evaluate potential seal materials. This testing procedure was used in a previous study of oxide ceramic fibers which were found to exhibit wear behavior based predominantly on their mechanical properties. Like the oxide fibers tested previously, these carbide oxide ceramic fibers, show an increase in friction and wear with increased test temperature. At room temperature, the wear behavior seems to be based upon mechanical properties, namely tensile strength. At 500 and especially 900 C, the fibers wear by both mechanical fracture and by oxidative type wear. Based upon post test microscopic and x ray analyses, interaction between the fiber constituents and elements transferred from the counterface, namely Ni and Cr, may have occurred enhancing the tribochemical wear process. These results are interpreted.

  1. Modeling the Effect of Oxidation on Tensile Strength of Carbon Fiber-Reinforced Ceramic-Matrix Composites

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2015-12-01

    An analytical method has been developed to investigate the effect of oxidation on the tensile strength of carbon fiber - reinforced ceramic - matrix composites (CMCs). The Budiansky - Hutchinson - Evans shear - lag model was used to describe the micro stress field of the damaged composite considering fibers failure. The statistical matrix multicracking model and fracture mechanics interface debonding criterion were used to determine the matrix crack spacing and interface debonded length. The fiber strength degradation model and oxidation region propagation model have been adopted to analyze the oxidation effect on tensile strength of the composite, which is controlled by diffusion of oxygen gas through matrix cracks. Under tensile loading, the fibers failure probabilities were determined by combining oxidation model and fiber statistical failure model based on the assumption that fiber strength is subjected to two-parameter Weibull distribution and the loads carried by broken and intact fibers statisfy the global load sharing criterion. The composite can no longer support the applied load when the total loads supported by broken and intact fibers approach its maximum value. The conditions of a single matrix crack and matrix multicrackings for tensile strength considering oxidation time and temperature have been analyzed.

  2. Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

    SciTech Connect

    Herklotz, A.; Dörr, K.; Ward, T. Z.; Eres, G.; Christen, H. M.; Biegalski, M. D.

    2015-03-30

    To have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can be utilized to determine the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr{sub n+1}Ti{sub n}O{sub 3n+1} Ruddlesden-Popper phases are grown with good long-range order. This method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.

  3. Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

    SciTech Connect

    Herklotz, A.; Dörr, Kathrin; Ward, T. Z.; Eres, G.; Christen, H. M.; Biegalski, Michael D.

    2015-04-03

    In this paper, to have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can be utilized to determine the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr n +1Ti n O3 n +1 Ruddlesden-Popper phases are grown with good long-range order. Finally, this method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.

  4. Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

    DOE PAGESBeta

    Herklotz, A.; Dörr, Kathrin; Ward, T. Z.; Eres, G.; Christen, H. M.; Biegalski, Michael D.

    2015-04-03

    In this paper, to have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can bemore » utilized to determine the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr n +1Ti n O3 n +1 Ruddlesden-Popper phases are grown with good long-range order. Finally, this method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.« less

  5. Oxidation and temperature effects on the interfacial shear strength in SCS-6 fiber-reinforced reaction-bonded silicon nitride

    SciTech Connect

    Guermazi, M.

    1995-01-01

    The fiber/matrix interfacial shear strength of Textron SCS-6 SiC-fiber-reinforced reaction-bonded Si{sub 3}N{sub 4} (RBSN) was studied as a function of temperature after oxidation for 24 h at 600 C. Fiber push-out experiments were conducted using a diamond indenter in a high-temperature microhardness tester under vacuum. The interfacial shear strength increased with temperature because of the relief of residual tensile stresses arising from the difference in thermal expansion coefficients between the fiber and the matrix. Most of sublayer 2 of the fiber outer coating, which mainly consisted of carbon in the form of BSU (basic structure unit) aggregates, had disappeared after the heat treatment of the composite. Oxidation resulted in severe changes in the fiber outer coating and caused a lower interfacial shear strength with respect to that of the unoxidized composite.

  6. Stressed-Oxidation Lifetime of Different SiC Fiber, CVI Matrix SiC Minicomposites in Air

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.; Martinez-Fernandez, Julian

    1998-01-01

    The stressed-oxidation lifetime properties of several minicomposites composed of single fiber tows with a CVI SiC matrix were compared. The minicomposites were made up of Nicalon(Tm) and Hi-Nicalon(Tm) SiC fibers with carbon or BN interphases. Constant load stress-rupture tests were performed between 600 and 13000 C in air for all of the minicomposite systems. Cyclic load testing was performed on the Hi-Nicalon minicomposite systems. The factors controlling the different lifetime behaviors: fiber rupture properties, interphase oxidation, fiber degradation, and fiber-matrix bonding, are discussed in light of different minicomposite constituents. All of the systems were subject to intermediate temperature embrittlement. The Hi-Nicalon fiber, BN interphase system, performed the best for constant load conditions. For cyclic load conditions, both the BN- interphase and C-interphase minicomposites displayed poor, but different failure behavior.

  7. Enhanced strain and temperature sensing by reduced graphene oxide coated etched fiber Bragg gratings.

    PubMed

    S, Sridevi; Vasu, K S; Asokan, S; Sood, A K

    2016-06-01

    This Letter reports on an etched fiber Bragg grating (eFBG) sensor coated with reduced graphene oxide (RGO) having enhanced sensitivity for physical parameters such as strain and temperature. The synergetic effect of the changes in grating pitch and refractive index of RGO with change in temperature or strain enhances the shift in Bragg wavelength (λB). The RGO-coated eFBG sensors exhibit a strain sensitivity of 5.5 pm/μϵ (∼5 times that of bare fiber Bragg gratings) and temperature sensitivity of 33 pm/°C (∼3 times that of bare fiber Bragg gratings). The resolutions of ∼1  μϵ and ∼0.3°C have been obtained for strain and temperature respectively, using RGO-coated eFBG sensors. PMID:27244425

  8. In situ growth of silver nanoparticles on TEMPO-oxidized jute fibers by microwave heating.

    PubMed

    Cao, Xinwang; Ding, Bin; Yu, Jianyong; Al-Deyab, Salem S

    2013-01-30

    Cellulose fibers deposited with metallic nanoparticles as one kind of renewable, biocompatible and antimicrobial nanomaterials evoke much interest because of their versatility in various applications. Herein, for the first time, a facile, simple and rapid method was developed to fabricate TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) selectively oxidized jute fibers in situ deposited with silver nanoparticles in the absence of reducing reagents. The average size of silver nanoparticles deposited on the fibers is 50.0 ± 2.0 nm by microwave heating for 5 min and 90.0 ± 4.7 nm for 10 min heating sample, respectively. The versatile jute-silver nanoparticles nanocomposites with superior thermal stability and high crystallinity would be particularly useful for applications in the public health care and biomedical fields. PMID:23218337

  9. Laser ablation of Drosophila embryonic motoneurons causes ectopic innervation of target muscle fibers

    NASA Technical Reports Server (NTRS)

    Chang, T. N.; Keshishian, H.

    1996-01-01

    We have tested the effects of neuromuscular denervation in Drosophila by laser-ablating the RP motoneurons in intact embryos before synaptogenesis. We examined the consequences of this ablation on local synaptic connectivity in both 1st and 3rd instar larvae. We find that the partial or complete loss of native innervation correlates with the appearance of alternate inputs from neighboring motor endings and axons. These collateral inputs are found at ectopic sites on the denervated target muscle fibers. The foreign motor endings are electrophysiologically functional and are observed on the denervated muscle fibers by the 1st instar larval stage. Our data are consistent with the existence of a local signal from the target environment, which is regulated by innervation and influences synaptic connectivity. Our results show that, despite the stereotypy of Drosophila neuromuscular connections, denervation can induce local changes in connectivity in wild-type Drosophila, suggesting that mechanisms of synaptic plasticity may also be involved in normal Drosophila neuromuscular development.

  10. Targeting oxidative stress in surgery: effects of ageing and therapy.

    PubMed

    Pepe, Salvatore; Leong, Jee-Yoong; Van der Merwe, Juliana; Marasco, Silvana F; Hadj, Anthony; Lymbury, Robyn; Perkins, Anthony; Rosenfeldt, Franklin L

    2008-07-01

    In the current era cardiac surgeons are being called upon to operate upon older, sicker patients. The effect is to augment oxidative stress and increase the rate of post-operative complications and ultimately mortality. We have developed antioxidant-based pre-treatment regimes initially based on coenzyme Q(10). A randomised trial of coenzyme Q(10) in elective cardiac surgery patients demonstrated augmented plasma and cardiac mitochondrial membrane coenzyme Q(10) content, improved mitochondrial respiration and increased myocardial tolerance of oxidative stress. The addition of omega-3 polyunsaturated fatty acids, alpha-lipoic acid, selenium and magnesium orotate in a second clinical trial, improved post-operative recovery with demonstrable reductions in myocardial damage, rate of atrial fibrillation and length of hospital stay. Finally we performed a pilot study of this combined metabolic therapy regimen to which we added preoperative physical exercise and mental stress reduction with indications of further improvements in post-operative recovery. We conclude that simultaneously targeting a number of key deficiencies with a metabolic formulation prior to surgery results in peri- and post-operative clinical and economic benefits. PMID:18468827

  11. Rapid oxidation/stabilization technique for carbon foams, carbon fibers and C/C composites

    DOEpatents

    Tan, Seng; Tan, Cher-Dip

    2004-05-11

    An enhanced method for the post processing, i.e. oxidation or stabilization, of carbon materials including, but not limited to, carbon foams, carbon fibers, dense carbon-carbon composites, carbon/ceramic and carbon/metal composites, which method requires relatively very short and more effective such processing steps. The introduction of an "oxygen spill over catalyst" into the carbon precursor by blending with the carbon starting material or exposure of the carbon precursor to such a material supplies required oxygen at the atomic level and permits oxidation/stabilization of carbon materials in a fraction of the time and with a fraction of the energy normally required to accomplish such carbon processing steps. Carbon based foams, solids, composites and fiber products made utilizing this method are also described.

  12. Oxidation behavior of single-crystal Al2O3-fiber-reinforced Ni3Al-based composites

    NASA Astrophysics Data System (ADS)

    Nourbakhsh, S.; Rhee, W. H.; Sahin, O.; Margolin, H.

    1994-07-01

    A series of single-crystal Al2O3-fiber-reinforced Ni3Al-based intermetallic matrix composites were fabricated by pressure casting. The matrices employed were binary Ni3Al, Ni3Al-0.5 at. pct Cr, and Ni3Al-0.34 at. pct Zr. The development of microstructure upon oxidation in air at either 1100 °C or 1200 °C was investigated by optical, scanning, and transmission electron microscopy. In air-oxidized binary Ni3Al, some of the fibers were fully or partially covered with a layer of oxide. A weak fiber/matrix bond in this system, which led to fiber debonding during composite processing, is believed to be responsible for the ingress of O into the composite and oxidation of the matrix in the debonded regions at the fiber/matrix interface. Addition of Cr to Ni3Al resulted in an almost threefold increase in fiber/matrix bond strength. No oxidation of the interface was observed. A thick layer of oxide was formed around all the fibers when the composite was thermally cycled prior to isothermal annealing. Addition of Zr to Ni3Al resulted in the formation of a layer of ZrO2 on the surface of the fibers during composite processing. The ZrO2 layer provided a fast path for the diffusion of O, which led to the formation of a rootlike oxide structure around the fibers. The rootlike structure consisted of a network of Al2O3-covered ZrO2.

  13. Subcellular targeting and trafficking of nitric oxide synthases

    PubMed Central

    Oess, Stefanie; Icking, Ann; Fulton, David; Govers, Roland; Müller-Esterl, Werner

    2006-01-01

    Unlike most other endogenous messengers that are deposited in vesicles, processed on demand and/or secreted in a regulated fashion, NO (nitric oxide) is a highly active molecule that readily diffuses through cell membranes and thus cannot be stored inside the producing cell. Rather, its signalling capacity must be controlled at the levels of biosynthesis and local availability. The importance of temporal and spatial control of NO production is highlighted by the finding that differential localization of NO synthases in cardiomyocytes translates into distinct effects of NO in the heart. Thus NO synthases belong to the most tightly controlled enzymes, being regulated at transcriptional and translational levels, through co- and post-translational modifications, by substrate availability and not least via specific sorting to subcellular compartments, where they are in close proximity to their target proteins. Considerable efforts have been made to elucidate the molecular mechanisms that underlie the intracellular targeting and trafficking of NO synthases, to ultimately understand the cellular pathways controlling the formation and function of this powerful signalling molecule. In the present review, we discuss the mechanisms and triggers for subcellular routing and dynamic redistribution of NO synthases and the ensuing consequences for NO production and action. PMID:16722822

  14. Targeted detection of murine colonic dysplasia in vivo with flexible multispectral scanning fiber endoscopy

    NASA Astrophysics Data System (ADS)

    Joshi, Bishnu P.; Miller, Sharon J.; Lee, Cameron; Gustad, Adam; Seibel, Eric J.; Wang, Thomas D.

    2012-02-01

    We demonstrate a multi-spectral scanning fiber endoscope (SFE) that collects fluorescence images in vivo from three target peptides that bind specifically to murine colonic adenomas. This ultrathin endoscope was demonstrated in a genetically engineered mouse model of spontaneous colorectal adenomas based on somatic Apc (adenomatous polyposis coli) gene inactivation. The SFE delivers excitation at 440, 532, 635 nm with <2 mW per channel. The target 7-mer peptides were conjugated to visible organic dyes, including 7-Diethylaminocoumarin-3-carboxylic acid (DEAC) (λex=432 nm, λem=472 nm), 5-Carboxytetramethylrhodamine (5-TAMRA) (λex=535 nm, λem=568 nm), and CF-633 (λex=633 nm, λem=650 nm). Target peptides were first validated using techniques of pfu counting, flow cytometry and previously established methods of fluorescence endoscopy. Peptides were applied individually or in combination and detected with fluorescence imaging. The ability to image multiple channels of fluorescence concurrently was successful for all three channels in vitro, while two channels were resolved simultaneously in vivo. Selective binding of the peptide was evident to adenomas and not to adjacent normal-appearing mucosa. Multispectral wide-field fluorescence detection using the SFE is achievable, and this technology has potential to advance early cancer detection and image-guided therapy in human patients by simultaneously visualizing multiple over expressed molecular targets unique to dysplasia.

  15. Thermal oxidation induced degradation of carbon fiber reinforced composites and carbon nanotube sheet enhanced fiber/matrix interface for high temperature aerospace structural applications

    NASA Astrophysics Data System (ADS)

    Haque, Mohammad Hamidul

    Recent increase in the use of carbon fiber reinforced polymer matrix composite, especially for high temperature applications in aerospace primary and secondary structures along with wind energy and automotive industries, have generated new challenges to predict its failure mechanisms and service life. This dissertation reports the experimental study of a unidirectional carbon fiber reinforced bismaleimide (BMI) composites (CFRC), an excellent candidate for high temperature aerospace components, undergoing thermal oxidation at 260 °C in air for over 3000 hours. The key focus of the work is to investigate the mechanical properties of the carbon fiber BMI composite subjected to thermal aging in three key aspects - first, studying its bulk flexural properties (in macro scale), second, characterizing the crack propagation along the fiber direction, representing the interfacial bonding strength between fiber and matrix (in micro scale), and third, introducing nano-structured materials to modify the interface (in nano scale) between the carbon fiber and BMI resin and mechanical characterization to study its influence on mitigating the aging effect. Under the first category, weight loss and flexural properties have been monitored as the oxidation propagates through the fiber/matrix interface. Dynamic mechanical analysis and micro-computed tomography analysis have been performed to analyze the aging effects. In the second category, the long-term effects of thermal oxidation on the delamination (between the composite plies) and debonding (between fiber and matrix) type fracture toughness have been characterized by preparing two distinct types of double cantilever beam specimens. Digital image correlation has been used to determine the deformation field and strain distribution around the crack propagation path. Finally the resin system and the fiber/matrix interface have been modified using nanomaterials to mitigate the degradations caused by oxidation. Nanoclay modified

  16. ReaxFF Study of the Oxidation of Softwood Lignin in View of Carbon Fiber Production

    SciTech Connect

    Beste, Ariana

    2014-01-01

    We investigate the oxidative, thermal conversion of softwood lignin by performing molecular dynamics simulations based on a reactive force field (ReaxFF). The lignin samples are constructed from coniferyl alcohol units, which are connected through linkages that are randomly selected from a natural distribution of linkages in softwood. The goal of this work is to simulate the oxidative stabilization step during carbon fiber production from lignin precursor. We find that at simulation conditions where stabilization reactions occur, the lignin fragments have already undergone extensive degradation. The 5-5 linkage shows the highest reactivity towards cyclization and dehydrogenation.

  17. ReaxFF Study of the Oxidation of Softwood Lignin in View of Carbon Fiber Production

    DOE PAGESBeta

    Beste, Ariana

    2014-10-06

    We investigate the oxidative, thermal conversion of softwood lignin by performing molecular dynamics simulations based on a reactive force field (ReaxFF). The lignin samples are constructed from coniferyl alcohol units, which are connected through linkages that are randomly selected from a natural distribution of linkages in softwood. The goal of this work is to simulate the oxidative stabilization step during carbon fiber production from lignin precursor. We find that at simulation conditions where stabilization reactions occur, the lignin fragments have already undergone extensive degradation. The 5-5 linkage shows the highest reactivity towards cyclization and dehydrogenation.

  18. Nitric oxide targets oligodendrocytes and promotes their morphological differentiation

    PubMed Central

    Garthwaite, Giti; Hampden-Smith, Kathryn; Wilson, Gary W; Goodwin, David A; Garthwaite, John

    2015-01-01

    In the central nervous system, nitric oxide (NO) transmits signals from one neurone to another, or from neurones to astrocytes or blood vessels, but the possibility of oligodendrocytes being physiological NO targets has been largely ignored. By exploiting immunocytochemistry for cGMP, the second messenger generated on activation of NO receptors, oligodendrocytes were found to respond to both exogenous and endogenous NO in cerebellar slices from rats aged 8 days to adulthood. Atrial natriuretic peptide, which acts on membrane-associated guanylyl cyclase-coupled receptors, also raised oligodendrocyte cGMP in cerebellar slices. The main endogenous source of NO accessing oligodendrocytes appeared to be the neuronal NO synthase isoform, which was active even under basal conditions and in a manner that was independent of glutamate receptors. Oligodendrocytes in brainstem slices were also shown to be potential NO targets. In contrast, in the optic nerve, oligodendrocyte cGMP was raised by natriuretic peptides but not NO. When cultures of cerebral cortex were continuously exposed to low NO concentrations (estimated as 40–90 pM), oligodendrocytes responded with a striking increase in arborization. This stimulation of oligodendrocyte growth could be replicated by low concentrations of 8-bromo-cGMP (maximum effect at 1 µM). It is concluded that oligodendrocytes are probably widespread targets for physiological NO (or natriuretic peptide) signals, with the resulting rise in cGMP serving to enhance their growth and maturation. NO might help coordinate the myelination of axons to the ongoing level of neuronal activity during development and could potentially contribute to adaptive changes in myelination in the adult. PMID:25327839

  19. Mechanism of Ad5 Vaccine Immunity and Toxicity: Fiber Shaft Targeting of Dendritic Cells

    PubMed Central

    Kong, Wing-pui; Sheets, Rebecca L; Gomez, Phillip L; King, C. Richter; Nabel, Gary J

    2007-01-01

    Recombinant adenoviral (rAd) vectors elicit potent cellular and humoral immune responses and show promise as vaccines for HIV-1, Ebola virus, tuberculosis, malaria, and other infections. These vectors are now widely used and have been generally well tolerated in vaccine and gene therapy clinical trials, with many thousands of people exposed. At the same time, dose-limiting adverse responses have been observed, including transient low-grade fevers and a prior human gene therapy fatality, after systemic high-dose recombinant adenovirus serotype 5 (rAd5) vector administration in a human gene therapy trial. The mechanism responsible for these effects is poorly understood. Here, we define the mechanism by which Ad5 targets immune cells that stimulate adaptive immunity. rAd5 tropism for dendritic cells (DCs) was independent of the coxsackievirus and adenovirus receptor (CAR), its primary receptor or the secondary integrin RGD receptor, and was mediated instead by a heparin-sensitive receptor recognized by a distinct segment of the Ad5 fiber, the shaft. rAd vectors with CAR and RGD mutations did not infect a variety of epithelial and fibroblast cell types but retained their ability to transfect several DC types and stimulated adaptive immune responses in mice. Notably, the pyrogenic response to the administration of rAd5 also localized to the shaft region, suggesting that this interaction elicits both protective immunity and vector-induced fevers. The ability of replication-defective rAd5 viruses to elicit potent immune responses is mediated by a heparin-sensitive receptor that interacts with the Ad5 fiber shaft. Mutant CAR and RGD rAd vectors target several DC and mononuclear subsets and induce both adaptive immunity and toxicity. Understanding of these interactions facilitates the development of vectors that target DCs through alternative receptors that can improve safety while retaining the immunogenicity of rAd vaccines. PMID:17319743

  20. Experimental research on the penetration of tungsten-fiber/metallic-glass matrix composite material bullet into steel target

    NASA Astrophysics Data System (ADS)

    Chen, X. W.; Chen, G.

    2012-08-01

    In the present paper, the penetration experiments of tungsten-fiber/metallic-glass matrix composite material bullets into 45# steel targets are conducted by employing H25 artillery. In which, an experimental technique of sub-caliber penetration is constructed. The quasi static and dynamic behaviours of tungsten-fiber/metallic-glass matrix composite material are also experimental investigated. The self-sharpening phenomenon of composite material is observed. Integrated with metallographic analysis, the failure modes of tungsten-fiber/metallic-glass matrix composite material are identified systemically and compared with the quasi-static and dynamic material tests. It includes four failure modes, i.e., shear fracture of tungsten fiber, brittle fracture of tungsten fiber and shear fracture of metallic glass matrix as well as melting of tungsten fiber and metallic glass matrix. Comparatively, three failure mechanisms of tungsten fiber in the bullet nose are also identified, i.e., shear fracture, splitting fracture and bending or/and buckling. Finally, the mechanism of self-sharpening behaviour of tungsten-fiber/metallic-glass matrix composite material is discussed.

  1. Fiber

    MedlinePlus

    ... broccoli, spinach, and artichokes legumes (split peas, soy, lentils, etc.) almonds Look for the fiber content of ... salsa, taco sauce, and cheese for dinner. Add lentils or whole-grain barley to your favorite soups. ...

  2. Fiber

    MedlinePlus

    ... short period of time can cause intestinal gas ( flatulence ), bloating , and abdominal cramps . This problem often goes ... 213. National Research Council. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and ...

  3. System simulation method for fiber-based homodyne multiple target interferometers using short coherence length laser sources

    NASA Astrophysics Data System (ADS)

    Fox, Maik; Beuth, Thorsten; Streck, Andreas; Stork, Wilhelm

    2015-09-01

    Homodyne laser interferometers for velocimetry are well-known optical systems used in many applications. While the detector power output signal of such a system, using a long coherence length laser and a single target, is easily modelled using the Doppler shift, scenarios with a short coherence length source, e.g. an unstabilized semiconductor laser, and multiple weak targets demand a more elaborated approach for simulation. Especially when using fiber components, the actual setup is an important factor for system performance as effects like return losses and multiple way propagation have to be taken into account. If the power received from the targets is in the same region as stray light created in the fiber setup, a complete system simulation becomes a necessity. In previous work, a phasor based signal simulation approach for interferometers based on short coherence length laser sources has been evaluated. To facilitate the use of the signal simulation, a fiber component ray tracer has since been developed that allows the creation of input files for the signal simulation environment. The software uses object oriented MATLAB code, simplifying the entry of different fiber setups and the extension of the ray tracer. Thus, a seamless way from a system description based on arbitrarily interconnected fiber components to a signal simulation for different target scenarios has been established. The ray tracer and signal simulation are being used for the evaluation of interferometer concepts incorporating delay lines to compensate for short coherence length.

  4. Comparison of adenovirus fiber, protein IX, and hexon capsomeres as scaffolds for vector purification and cell targeting

    SciTech Connect

    Campos, Samuel K.; Barry, Michael A. . E-mail: mab@bcm.edu

    2006-06-05

    The direct genetic modification of adenoviral capsid proteins with new ligands is an attractive means to confer targeted tropism to adenoviral vectors. Although several capsid proteins have been reported to tolerate the genetic fusion of foreign peptides and proteins, direct comparison of cell targeting efficiencies through the different capsomeres has been lacking. Likewise, direct comparison of with one or multiple ligands has not been performed due to a lack of capsid-compatible ligands available for retargeting. Here we utilize a panel of metabolically biotinylated Ad vectors to directly compare targeted transduction through the fiber, protein IX, and hexon capsomeres using a variety of biotinylated ligands including antibodies, transferrin, EGF, and cholera toxin B. These results clearly demonstrate that cell targeting with a variety of high affinity receptor-binding ligands is only effective when transduction is redirected through the fiber protein. In contrast, protein IX and hexon-mediated targeting by the same set of ligands failed to mediate robust vector targeting, perhaps due to aberrant trafficking at the cell surface or inside targeted cells. These data suggest that vector targeting by genetic incorporation of high affinity ligands will likely be most efficient through modification of the adenovirus fiber rather than the protein IX and hexon capsomeres. In contrast, single-step monomeric avidin affinity purification of Ad vectors using the metabolic biotinylation system is most effective through capsomeres like protein IX and hexon.

  5. Adsorption of SO2 onto oxidized and heat-treated activated carbon fibers (ACFS)

    USGS Publications Warehouse

    Daley, M.A.; Mangun, C.L.; DeBarr, J.A.; Riha, S.; Lizzio, A.A.; Donnals, G.L.; Economy, J.

    1997-01-01

    A series of activated carbon fibers (ACFs) and heat-treated oxidized ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore surface chemistry and pore volume for the adsorption of SO2 and its catalytic conversion to H2SO4. For untreated ACFs, the initial rate of SO2 adsorption from flue gas was shown to be inversely related to pore size. At longer times, the amount of SO2 adsorbed from flue gas was dependent on both the pore size and pore volume. Oxidation of the ACFs, using an aqueous oxidant, decreased their adsorption capacity for SO2 from flue gas due to a decrease in pore volume and repulsion of the SO2 from acidic surface groups. If these samples were heat-treated to desorb the oxygen containing function groups, the amount of SO2 adsorption increased. This increase in adsorption capacity was directly correlated to the amount of CO2 evolved during heat-treatment of the oxidized ACFs. The amount of SO2 adsorbed for these samples was related to the pore size, pore surface chemistry and pore volume. This analysis is explained in more detail in this paper. ?? 1997 Elsevier Science Ltd. All rights reserved.

  6. Targeting of nitric oxide synthase to endothelial cell caveolae via palmitoylation: implications for nitric oxide signaling.

    PubMed Central

    García-Cardeña, G; Oh, P; Liu, J; Schnitzer, J E; Sessa, W C

    1996-01-01

    The membrane association of endothelial nitric oxide synthase (eNOS) plays an important role in the biosynthesis of nitric oxide (NO) in vascular endothelium. Previously, we have shown that in cultured endothelial cells and in intact blood vessels, eNOS is found primarily in the perinuclear region of the cells and in discrete regions of the plasma membrane, suggesting trafficking of the protein from the Golgi to specialized plasma membrane structures. Here, we show that eNOS is found in Triton X-100-insoluble membranes prepared from cultured bovine aortic endothelial cells and colocalizes with caveolin, a coat protein of caveolae, in cultured bovine lung microvascular endothelial cells as determined by confocal microscopy. To examine if eNOS is indeed in caveolae, we purified luminal endothelial cell plasma membranes and their caveolae directly from intact, perfused rat lungs. eNOS is found in the luminal plasma membranes and is markedly enriched in the purified caveolae. Because palmitoylation of eNOS does not significantly influence its membrane association, we next examined whether this modification can affect eNOS targeting to caveolae. Wild-type eNOS, but not the palmitoylation mutant form of the enzyme, colocalizes with caveolin on the cell surface in transfected NIH 3T3 cells, demonstrating that palmitoylation of eNOS is necessary for its targeting into caveolae. These data suggest that the subcellular targeting of eNOS to caveolae can restrict NO signaling to specific targets within a limited microenvironment at the cell surface and may influence signal transduction through caveolae. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8692835

  7. Mitochondria-Mediated Oxidative Stress: Old Target for New Drugs.

    PubMed

    Lyakhovich, Alex; Graifer, Dmitri

    2015-01-01

    Oxidative stress, one of the crucial factors of genomic instability, is involved in many illnesses - from DNA damage and repair (DDR) related diseases to neurological abnormalities and cancer. Patients with defective DDR pathways display high level of cancer predisposition and at the same time - reveal hydrocephalia, dementias and even diabetes mellitus - all representing common hallmarks of mitochondria-related disorders. Since mitochondria are responsible both for the cell energetic metabolism and for reactive oxygen/nitrogen species (RO/NS) formation, mitochondrial dysfunction (MDF) play a pivotal role in the above disorders. Not surprisingly, RO/NS are considered to be a primary target for a large spectrum of compounds aiming to eliminate these adverse species or, in contrary, enhance their presence in order to amplify cellular death pathways. Yet, only few chemicals have received medical appreciation mainly because of their questionable therapeutic values in healthy states. As a result, recent efforts have been focused on finding the drugs that improve mitochondrial functions or chemoprevent MDF rather than being applied as RO/NS scavengers. This review addresses the most recent progress in the development and application of such chemicals and outlines some future perspectives. PMID:26219394

  8. Thermo-Oxidative Stability of Graphite/PMR-15 Composites: Effect of Fiber Surface Modification on Composite Shear Properties

    NASA Technical Reports Server (NTRS)

    Madhukar, Madhu S.; Bowles, Kenneth J.; Papadopolous, Demetrios S.

    1994-01-01

    Experiments were conducted to establish a correlation between the weight loss of a polyimide (PMR- 15) matrix and graphite fibers and the in-plane shear properties of their unidirectional composites subjected to different isothermal aging times up to 1000 hr at 316 C. The role of fiber surface treatment on the composite degradation during the thermo-oxidative aging was investigated by using A4 graphite fibers with three surface modifications: untreated (AU-4), surface treated (AS-4), and surface treated and sized with an epoxy-compatible sizing (AS-4G). The weight loss of the matrix fibers, and composites was determined during the aging. The effect of thermal aging was seen in all the fiber samples in terms of weight loss and reduction in fiber diameter. Calculated values of weight loss fluxes for different surfaces of rectangular unidirectional composite plates showed that the largest weight loss occurred at those cut surfaces where fibers were perpendicular to the surface. Consequently, the largest amount of damage was also noted on these cut surfaces. Optical observation of the neat matrix and composite plates subjected to different aging times revealed that the degradation (such as matrix microcracking and void growth) occurred in a thin surface layer near the specimen edges. The in-plane shear modulus of the composites was unaffected by the fiber surface treatment and the thermal aging. The shear strength of the composites with the untreated fibers was the lowest and it decreased with aging. A fracture surface examination of the composites with untreated fibers suggested that the weak interface allowed the oxidation reaction to proceed along the interface and thus expose the inner material to further oxidation. The results indicated that the fiber-matrix interface affected the composite degradation process during its thermal aging and that the the weak interface accelerated the composite degradation.

  9. Composite polymer/oxide hollow fiber contactors: versatile and scalable flow reactors for heterogeneous catalytic reactions in organic synthesis.

    PubMed

    Moschetta, Eric G; Negretti, Solymar; Chepiga, Kathryn M; Brunelli, Nicholas A; Labreche, Ying; Feng, Yan; Rezaei, Fateme; Lively, Ryan P; Koros, William J; Davies, Huw M L; Jones, Christopher W

    2015-05-26

    Flexible composite polymer/oxide hollow fibers are used as flow reactors for heterogeneously catalyzed reactions in organic synthesis. The fiber synthesis allows for a variety of supported catalysts to be embedded in the walls of the fibers, thus leading to a diverse set of reactions that can be catalyzed in flow. Additionally, the fiber synthesis is scalable (e.g. several reactor beds containing many fibers in a module may be used) and thus they could potentially be used for the large-scale production of organic compounds. Incorporating heterogeneous catalysts in the walls of the fibers presents an alternative to a traditional packed-bed reactor and avoids large pressure drops, which is a crucial challenge when employing microreactors. PMID:25865826

  10. Oxidation kinetics of coated silicon carbide fiber-reinforced silicon carbide (SiC/SiC)

    SciTech Connect

    Fox, D.S.

    1994-12-31

    Silicon carbide fiber-reinforced silicon carbide (SiC/SiC) was exposed for 100 hours to dry, flowing oxygen. Oxidation kinetics were determined via thermogravimetric analysis at 981{degrees}, 1204{degrees} and 1316{degrees}C (1800{degrees}, 2200{degrees} and 2400{degrees}F). The effectiveness of three external coating systems applied for oxidation protection is discussed. In all cases, weight gains were observed, and the pyrolytic carbon interface layer remained intact. A CVD SiC external coating is the most promising due to low oxidation kinetics resulting from solid silica formation. A borosilicate glass was observed on the surface of two of the materials that have boron-containing coatings.

  11. Tunable Q-switched fiber laser using zinc oxide nanoparticles as a saturable absorber.

    PubMed

    Ahmad, H; Lee, C S J; Ismail, M A; Ali, Z A; Reduan, S A; Ruslan, N E; Harun, S W

    2016-06-01

    Nanomaterials have ignited new interest due to their distinctive electronic, mechanical, and optical properties. Zinc oxide nanostructures are fabricated into thin film and then inserted between two fiber ferrules to act as a saturable absorber (SA). The modulation depth and insertion loss of the SA are 5% and 3.5 dB, respectively. When the ZnO-SA is incorporated into the laser cavity, a stable Q-switched pulse tunable from 1536 to 1586 nm (50 nm range) with pulse energy up to 46 nJ was observed. Our result suggests that ZnO is a promising broadband SA to generate passively Q-switched fiber lasers. PMID:27411175

  12. Effect of atmospheric oxidative plasma treatments on polypropylenic fibers surface: Characterization and reaction mechanisms

    NASA Astrophysics Data System (ADS)

    Nisticò, Roberto; Magnacca, Giuliana; Faga, Maria Giulia; Gautier, Giovanna; D'Angelo, Domenico; Ciancio, Emanuele; Lamberti, Roberta; Martorana, Selanna

    2013-08-01

    Atmospheric pressure plasma-dielectric barrier discharge (APP-DBD, open chamber configuration) was used to functionalize polypropylene (PP) fibers surface in order to generate oxidized-reactive groups such as hydroperoxides, alcohols and carbonyl species (i.e. ketones and others). Such a species increased the surface polarity, without causing material degradation. Three different types of plasma mixture (He, He/O2, He/O2/H2O) under three different values of applied power (750, 1050, 1400 W) were investigated. The formed plasma species (O2+, O single atom and OH radical) and their distribution were monitored via optical emission spectrometry (OES) measurements, and the plasma effects on PP surface species formation were followed by X-ray photoemission spectroscopy (XPS). Results allowed to better understand the reaction pathways between plasma phase and PP fibers. In fact, two reaction mechanisms were proposed, the first one concerning the plasma phase reactions and the second one involving material surface modifications.

  13. Parallel expression evolution of oxidative stress-related genes in fiber from wild and domesticated diploid and polyploid cotton (Gossypium)

    PubMed Central

    2009-01-01

    Background Reactive oxygen species (ROS) play a prominent role in signal transduction and cellular homeostasis in plants. However, imbalances between generation and elimination of ROS can give rise to oxidative stress in growing cells. Because ROS are important to cell growth, ROS modulation could be responsive to natural or human-mediated selection pressure in plants. To study the evolution of oxidative stress related genes in a single plant cell, we conducted comparative expression profiling analyses of the elongated seed trichomes ("fibers") of cotton (Gossypium), using a phylogenetic approach. Results We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes in progenitor diploid species revealed significant up-regulation of ROS scavenging and potential signaling processes in domesticated G. arboreum. Similarly, in two independently domesticated allopolyploid species (G. barbadense and G. hirsutum) antioxidant genes were substantially up-regulated in comparison to antecedent wild forms. In contrast, analyses of three wild allopolyploid species indicate that genomic merger and ancient allopolyploid formation had no significant influences on regulation of ROS related genes. Remarkably, many of the ROS-related processes diagnosed as possible targets of selection were shared among diploid and allopolyploid cultigens, but involved different sets of antioxidant genes. Conclusion Our data suggests that parallel human selection for enhanced fiber growth in several geographically widely dispersed species of domesticated cotton resulted in similar and overlapping metabolic transformations of the manner in which cellular redox levels have become modulated. PMID:19686594

  14. Functional pools of oxidative and glycolytic fibers in human muscle observed by /sup 31/P magnetic resonance spectroscopy during exercise

    SciTech Connect

    Park, J.H.; Brown, R.L.; Park, C.R.; McCully, K.; Cohn, M.; Haselgrove, J.; Chance, B.

    1987-12-01

    Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative fibers. A differential recruitment of oxidative and glycolytic fibers during exercise was demonstrated in 4 of 10 untrained young men by following changes in phosphate metabolites. Concentrations of inorganic phosphate (P/sub i/), phosphocreatine, and ATP were estimated in the wrist flexor muscles of the forearm at rest, during two cycles of three grades of exercise, and in recovery. At high work levels (40% of maximum strength), two distinct P/sub i/ peaks were observed and identified with P/sub i/ pools at pH 6.9 and pH 5.9-6.4, respectively. These could be accounted for as follows. At the lowest level of work (using 20% of maximum strength), early recruitment primarily of oxidative (type I) and possibly some intermediate (type IIA) muscle fibers occurs with relatively little net lactate production and consequently little decrease in pH. At higher work loads, however, primarily glycolytic (type IIB) muscle fibers are recruited, which have relatively high net lactate production and therefore generate a second pool of P/sub i/ at low pH. These observations indicated exhaustion of glycolytic type IIB fibers, removal of lactate by high local blood flow, and sustained contractions largely by oxidative type I and IIA fibers. A functional differentiation of fiber types could also be demonstrated during recovery if exercise was stopped while two pools of P/sub i/ were still apparent. The potential of magnetic resonance spectroscopy to characterize oxidative and glycolytic fibers, predict capacity for aerobic performance, and signal the presence of muscle pathology is discussed.

  15. Oxidation-resistant interfacial coatings for fiber-reinforced ceramic composites

    SciTech Connect

    Lara-Curzio, Edgar; More, Karren L.; Lee, Woo Y.

    1999-04-22

    A ceramic-matrix composite having a multilayered interfacial coating adapted to protect the reinforcing fibers from long-term oxidation, while allowing these to bridge the wake of advancing cracks in the matrix, is provided by selectively mismatching materials within adjacent layers of the interfacial coating, the materials having different coefficients of thermal expansion so that a low toughness interface region is created to promote crack deflection either within an interior layer of the mismatched interfacial coating or between adjacent layers of the mismatched interfacial coating.

  16. Fermentable dietary fibers elevate urinary methylmalonate and decrease propionate oxidation in rats deprived of vitamin B-12.

    PubMed

    Cullen, R W; Oace, S M

    1989-08-01

    This study examines the effect of dietary fiber supplements of different degrees of bacterial fermentability on biochemical indicators of vitamin B-12 deficiency in rats. Groups of rats were fed a fiber-free diet deficient in vitamin B-12 or the fiber-free diet diluted with 5% of a poorly fermentable dietary fiber (cellulose, lignin or alginic acid) or a highly fermentable fiber (pectin, guar gum or xylan). Poorly fermentable fibers had no significant effect on apparent B-12 status, whereas the highly fermentable fibers significantly increased urinary methylmalonic acid and depressed oxidation of [14C]propionate to 14CO2. Pectin consistently induced significantly greater effects than did xylan or guar gum. The data are consistent with the hypothesis that fermentable fibers stimulate bacterial propionate production and exaggerate certain biochemical indicators of B-12 deficiency. Since pectin had a more pronounced effect than did other fermentable fibers, the possibility that pectin may also interfere with B-12 absorption requires further study. PMID:2550598

  17. Graphite Sheet Coating for Improved Thermal Oxidative Stability of Carbon Fiber Reinforced/PMR-15 Composites

    NASA Technical Reports Server (NTRS)

    Campbell, Sandi; Papadopoulos, Demetrios; Heimann, Paula; Inghram, Linda; McCorkle, Linda

    2005-01-01

    Expanded graphite was compressed into graphite sheets and used as a coating for carbon fiber reinforced PMR-15 composites. BET analysis of the graphite indicated an increase in graphite pore size on compression, however the material was proven to be an effective barrier to oxygen when prepegged with PMR-15 resin. Oxygen permeability of the PMR-15/graphite was an order of magnitude lower than the compressed graphite sheet. By providing a barrier to oxygen permeation, the rate of oxidative degradation of PMR-15 was decreased. As a result, the composite thermo-oxidative stability increased by up to 25%. The addition of a graphite sheet as a top ply on the composites yielded little change in the material's flexural strength or interlaminar shear strength.

  18. Titanium-Dioxide Nano-Fiber-Cotton Targets for Efficient Multi-keV X-Ray Generation

    SciTech Connect

    Tanabe, M; Nishimura, H; Fujioka, S; Nagai, K; Yamamoto, N; Gu, Z; Pan, C; Girard, F; Primout, M; Villette, B; Brebion, D; Fournier, K B; Fujishima, A; Mima, K

    2008-06-12

    Multi-keV x-ray generation from low-density (27 {+-} 7 mg/cc) nano-fiber-cotton targets composed of titanium-dioxide has been investigated. The cotton targets were heated volumetrically and supersonically to a peak electron temperature of 2.3 keV, which is optimal to yield Ti K-shell x rays. Considerable enhancement of conversion efficiency (3.7 {+-} 0.5%) from incident laser energy into Ti K-shell x rays (4-6 keV band) was attained in comparison with that (1.4 {+-} 0.9%) for a planar Ti-foil target.

  19. Immobilization of pectinase on oxidized pulp fiber and its application in whitewater treatment.

    PubMed

    Wu, Rina; He, Bei-Hai; Zhao, Guang-Lei; Qian, Li-Ying; Li, Xiao-Feng

    2013-09-12

    Modified pulp fiber was originally used as a new type of carrier for pectinase immobilization. Pulp fiber was oxidized by sodium periodate to produce aldehyde groups for covalently binding with amino groups of pectinase. Results showed that the enzymatic activity of immobilized pectinase on pulp fiber reached 65 μgg(-1)min(-1) when immobilization pH value, temperature and time were of 7.0, 20 °C and 15 min, respectively. The immobilized pectinase showed higher thermo stability in a wider temperature range of 40-70 °C than its free type and its optimal pH shifted from 8.0 to 8.8. Furthermore, the immobilized pectinase exhibited good operational stability. When employed in whitewater treatment of papermaking industry, it still efficiently decreased the cationic demand after operating repeatedly for six batches. The results obtained demonstrate a promising route to prepare available, cheap and biodegradable carrier for immobilizing enzymes with potential application in wastewater treatment in papermaking industry. PMID:23911480

  20. Fiber optic humidity sensor based on the graphene oxide/PVA composite film

    NASA Astrophysics Data System (ADS)

    Wang, Youqing; Shen, Changyu; Lou, Weimin; Shentu, Fengying

    2016-08-01

    Fiber optic humidity sensor based on an in-fiber Mach-Zehnder interferometer (MZI) coated with graphene oxide (GO)/PVA composite film was investigated. The MZI is constructed of two waist-enlarged tapers. The length between two waist-enlarged tapers is 20 mm. By comparing the experiment results of MZI coated with different GO/PVA composite films, composite film formed by the ratio of 0.3 g PVA mixed with 10 ml GO dispersion shows a better performance of relative humidity sensing. By using the molecular structure model of the composited GO/PVA, the operation mechanism between GO/PVA composite film and water molecules was illustrated. The sensitivity of 0.193 dB/%RH with a linear correlation coefficient of 99.1% and good stability under the relative humidity range of 25-80% was obtained. Temperature effect on the proposed fiber optic humidity sensor was also considered and analyzed. According to the repetitive experimental results, the proposed humidity sensor shows a good repeatability.

  1. From beads-to-wires-to-fibers of tungsten oxide: electrochromic response

    NASA Astrophysics Data System (ADS)

    Kadam, P. M.; Tarwal, N. L.; Shinde, P. S.; Patil, R. S.; Deshmukh, H. P.; Patil, P. S.

    2009-11-01

    Suitable host lattice and morphology for easy intercalation and deintercalation process are crucial requirements for electrochromic device. In this investigation, the evolution of structural and morphological changes and their effect on electrochromic (EC) properties of spray-deposited WO3 thin films are studied. Films of different morphologies were deposited from an ammonium tungstate precursor solution using a novel pulsed spray pyrolysis technique (PSPT) on tin-doped indium oxide (ITO) coated glass substrates by varying quantity of spraying solution. Interesting morphological transition from beads-to-wires-to-fibers as a function of quantity of sprayed solution has been demonstrated. The porosity, crystallinity and “open” structures in the films consisting of beads, wires, and fiber-like morphology enabled us to correlate these aspects to their EC performance. WO3 films comprising wire-like morphology (20 cc spraying quantity) exhibited better EC properties both in terms of coloration efficiency (42.7 cm2/C) and electrochemical stability (103 colored/bleached cycles) owing to their adequate open structure, porosity, and amorphicity, compared with the films having bead/fiber-like morphology.

  2. Sol-gel nanocasting synthesis of patterned hierarchical LaFeO3 fibers with enhanced catalytic CO oxidation activity.

    PubMed

    Li, Pengna; Hu, Xianluo; Zhang, Lei; Dai, Hongxing; Zhang, Lizhi

    2011-03-01

    Hierarchical LaFeO3 fibers were prepared by a sol-gel nanocasting method using a cotton cloth as the template. The resulting LaFeO3 fibers inherited the initial network morphology of the template very well and showed enhanced catalytic CO oxidation activity and satisfactory stability compared to the counterpart particles prepared by the conventional sol-gel method. PMID:21234504

  3. Fabrication and application of zinc-zinc oxide nanosheets coating on an etched stainless steel wire as a selective solid-phase microextraction fiber.

    PubMed

    Song, Wenlan; Guo, Mei; Zhang, Yida; Zhang, Min; Wang, Xuemei; Du, Xinzhen

    2015-03-01

    A novel zinc-zinc oxide (Zn-ZnO) nanosheets coating was directly fabricated on an etched stainless steel wire substrate as solid-phase microextraction (SPME) fiber via previous electrodeposition of robust Zn coating. The scanning electron micrograph of the Zn-ZnO nanosheets coated fiber exhibits a flower-like nanostructure with high surface area. The SPME performance of as-fabricated fiber was investigated for the concentration and determination of polycyclic aromatic hydrocarbons, phthalates and ultraviolet (UV) filters coupled to high performance liquid chromatography with UV detection (HPLC-UV). It was found that the Zn-ZnO nanosheets coating exhibited high extraction capability, good selectivity and rapid mass transfer for some UV filters. The main parameters affecting extraction performance were investigated and optimized. Under the optimized conditions, the calibration graphs were linear over the range of 0.1-200μgL(-1). The limits of detection of the proposed method were 0.052-0.084μgL(-1) (S/N=3). The single fiber repeatability varied from 5.18% to 7.56% and the fiber-to-fiber reproducibility ranged from 6.74% to 8.83% for the extraction of spiked water with 50μgL(-1) UV filters (n=5). The established SPME-HPLC-UV method was successfully applied to the selective concentration and sensitive determination of target UV filters from real environmental water samples with recoveries from 85.8% to 105% at the spiking level of 10μgL(-1) and 30μgL(-1). The relative standard deviations were below 9.7%. PMID:25662065

  4. Reduced graphene oxide coated optical fiber for methanol and ethanol vapor detection at room temperature

    NASA Astrophysics Data System (ADS)

    Kavinkumar, T.; Sastikumar, D.; Manivannan, S.

    2014-10-01

    Successful isolation of single layer of graphene from graphite by mechanical exfoliation method, attracted a great attention due to its unique structural, optical, mechanical and electronic properties. This makes the graphene as a promising material in many possible applications such as energy-storage, sensing, electronic, optical devices and polymer composite materials. High quality of reduced graphene oxide (rGO) material was prepared by chemical reduction method at 100°C. The structural and optical properties of the rGO sheets were characterized by FT-IR, micro Raman, powder XRD and UV-vis-NIR techniques. FT-IR reveals the absence of oxygen functional groups on rGO due to the reduction process. Powder XRD shows the broad peak at 2θ=24.3° corresponding to interlayer spacing 3.66Å which is smaller than the graphene oxide (GO). UV-vis-NIR of rGO displays the absorption peak at 271 nm indicates the reduction of GO and the restoration of C=C bonds in the rGO sheets. The cladding removed and rGO coated poly-methyl methacrylate (PMMA) optical fiber is used for methanol and ethanol vapors detection in the concentration ranging from 0 to 500 ppm at room temperature. The spectral characteristics along with output intensity modulation of cladding removed and rGO coated fiber optic sensor reveal the potential of methanol and ethanol vapor sensing properties.

  5. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    NASA Astrophysics Data System (ADS)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-12-01

    Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnOx) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnOx/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnOx layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO4 and then surface-deposition of MnOx particles from the bulk phase. The MnOx particles assembled with nanosheets were uniformly coated on the PET fibers. MnOx/PET showed good activity for HCHO decomposition at room temperature which followed the Mars-van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m3, space velocity ∼17,000 h-1 and relative humidity∼50%. This research provides a facile method to deposit active MnOx onto polymers with low air resistance, and composite MnOx/PET material is promising for indoor air purification.

  6. Cytotoxicity, oxidative stress and genotoxicity induced by glass fibers on human alveolar epithelial cell line A549.

    PubMed

    Rapisarda, Venerando; Loreto, Carla; Ledda, Caterina; Musumeci, Giuseppe; Bracci, Massimo; Santarelli, Lory; Renis, Marcella; Ferrante, Margherita; Cardile, Venera

    2015-04-01

    Man-made vitreous fibers have been widely used as insulation material as asbestos substitutes; however their morphology and composition raises concerns. In 1988 the International Agency for Research on Cancer classified fiberglass, rock wool, slag wool, and ceramic fibers as Group 2B, i.e. possibly carcinogenic to humans. In 2002 it reassigned fiberglass, rock and slag wool, and continuous glass filaments to Group 3, not classifiable as carcinogenic to humans. The aim of this study was to verify the cytotoxic and genotoxic effects and oxidative stress production induced by in vitro exposure of human alveolar epithelial cells A549 to glass fibers with a predominant diameter <3 μm (97%) and length >5 μm (93%). A549 cells were incubated with 5, 50, or 100 μg/ml (2.1, 21, and 42 μg/cm(2), respectively) of glass fibers for 72 h. Cytotoxicity and DNA damage were tested by the MTT and the Comet assay, respectively. Oxidative stress was determined by measuring inducible nitric oxide synthase (iNOS) expression by Western blotting, production of nitric oxide (NO) with Griess reagent, and concentration of reactive oxygen species by fluorescent quantitative analysis with 2',7'-dichlorofluorescein-diacetate (DCFH-DA). The results showed that glass fiber exposure significantly reduced cell viability and increased DNA damage and oxidative stress production in a concentration-dependent manner, demonstrating that glass fibers exert cytotoxic and genotoxic effects related to increased oxidative stress on the human alveolar cell line A549. PMID:25620604

  7. Fiber optic coupled optical sensor

    DOEpatents

    Fleming, Kevin J.

    2001-01-01

    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  8. Functional pools of oxidative and glycolytic fibers in human muscle observed by 31P magnetic resonance spectroscopy during exercise.

    PubMed

    Park, J H; Brown, R L; Park, C R; McCully, K; Cohn, M; Haselgrove, J; Chance, B

    1987-12-01

    Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative fibers. A differential recruitment of oxidative and glycolytic fibers during exercise was demonstrated in 4 of 10 untrained young men by following changes in phosphate metabolites. Concentrations of inorganic phosphate (Pi), phosphocreatine, and ATP were estimated in the wrist flexor muscles of the forearm at rest, during two cycles of three grades of exercise, and in recovery. At high work levels (40% of maximum strength), two distinct Pi peaks were observed and identified with Pi pools at pH 6.9 and pH 5.9-6.4, respectively. These could be accounted for as follows. At the lowest level of work (using 20% of maximum strength), early recruitment primarily of oxidative (type I) and possibly some intermediate (type IIA) muscle fibers occurs with relatively little net lactate production and consequently little decrease in pH. At higher work loads, however, primarily glycolytic (type IIB) muscle fibers are recruited, which have relatively high net lactate production and therefore generate a second pool of Pi at low pH. ATP depletion (35-54%) and Pi losses accompanied the reduction in ability to perform during the first exercise cycle. When the cycle of graded exercise was repeated immediately, the total Pi remained high but gave rise to only one peak at pH 6.8-7.0. These observations indicated exhaustion of glycolytic type IIB fibers, removal of lactate by high local blood flow, and sustained contractions largely by oxidative type I and IIA fibers. A functional differentiation of fiber types could also be demonstrated during recovery if exercise was stopped while two pools of Pi were still apparent. In the first 3 min of recovery, the Pi peak at pH 6.8-6.9 disappeared almost entirely, whereas the Pi peak at pH 6.0 remained unaltered, reflecting the faster recovery of

  9. Nitric oxide synthase inhibition and oxidative stress in cardiovascular diseases: possible therapeutic targets?

    PubMed

    Rochette, Luc; Lorin, Julie; Zeller, Marianne; Guilland, Jean-Claude; Lorgis, Luc; Cottin, Yves; Vergely, Catherine

    2013-12-01

    Nitric oxide (NO) is synthetized enzymatically from l-arginine (l-Arg) by three NO synthase isoforms, iNOS, eNOS and nNOS. The synthesis of NO is selectively inhibited by guanidino-substituted analogs of l-Arg or methylarginines such as asymmetric dimethylarginine (ADMA), which results from protein degradation in cells. Many disease states, including cardiovascular diseases and diabetes, are associated with increased plasma levels of ADMA. The N-terminal catalytic domain of these NOS isoforms binds the heme prosthetic group as well as the redox cofactor, tetrahydrobiopterin (BH(4)) associated with a regulatory protein, calmodulin (CaM). The enzymatic activity of NOS depends on substrate and cofactor availability. The importance of BH(4) as a critical regulator of eNOS function suggests that BH(4) may be a rational therapeutic target in vascular disease states. BH(4) oxidation appears to be a major contributor to vascular dysfunction associated with hypertension, ischemia/reperfusion injury, diabetes and other cardiovascular diseases as it leads to the increased formation of oxygen-derived radicals due to NOS uncoupling rather than NO. Accordingly, abnormalities in vascular NO production and transport result in endothelial dysfunction leading to various cardiovascular disorders. However, some disorders including a wide range of functions in the neuronal, immune and cardiovascular system were associated with the over-production of NO. Inhibition of the enzyme should be a useful approach to treat these pathologies. Therefore, it appears that both a lack and excess of NO production in diseases can have various important pathological implications. In this context, NOS modulators (exogenous and endogenous) and their therapeutic effects are discussed. PMID:23859953

  10. Targeted iron oxide nanoparticles for the enhancement of radiation therapy.

    PubMed

    Hauser, Anastasia K; Mitov, Mihail I; Daley, Emily F; McGarry, Ronald C; Anderson, Kimberly W; Hilt, J Zach

    2016-10-01

    To increase the efficacy of radiation, iron oxide nanoparticles can be utilized for their ability to produce reactive oxygen species (ROS). Radiation therapy promotes leakage of electrons from the electron transport chain and leads to an increase in mitochondrial production of the superoxide anion which is converted to hydrogen peroxide by superoxide dismutase. Iron oxide nanoparticles can then catalyze the reaction from hydrogen peroxide to the highly reactive hydroxyl radical. Therefore, the overall aim of this project was to utilize iron oxide nanoparticles conjugated to a cell penetrating peptide, TAT, to escape lysosomal encapsulation after internalization by cancer cells and catalyze hydroxyl radical formation. It was determined that TAT functionalized iron oxide nanoparticles and uncoated iron oxide nanoparticles resulted in permeabilization of the lysosomal membranes. Additionally, mitochondrial integrity was compromised when A549 cells were treated with both TAT-functionalized nanoparticles and radiation. Pre-treatment with TAT-functionalized nanoparticles also significantly increased the ROS generation associated with radiation. A long term viability study showed that TAT-functionalized nanoparticles combined with radiation resulted in a synergistic combination treatment. This is likely due to the TAT-functionalized nanoparticles sensitizing the cells to subsequent radiation therapy, because the nanoparticles alone did not result in significant toxicities. PMID:27521615

  11. A monitor and control system for high voltage, gating, and triggering of a scintillating fiber active target

    SciTech Connect

    Baumbaugh, B.; Bishop, J.; Gardner, R.W.; Mountain, R.J.; Ruchti, R.; Baumbaugh, A.; Knickerbocker, K.

    1988-02-01

    A monitor and control system has been designed, constructed and tested at Notre Dame for the purpose of controlling all aspects of a Scintillating Fiber Acxtive Target system used in High Energy Physics Experimentation. The SFT Active Target system requires control of high voltages, gating, trigger counters, and monitoring. In addition, it resides in a radioactive area with very limited access. The control system uses a Leading Edge microcomputer, two specialized Z80-based processors, associated DACs, ADCs, discrete semiconductors, linear ICs and TTL and MECL logic. All of the hardware and software is custom-built; its design and performance is discussed.

  12. A monitor and control system for high voltage, gating, and triggering of a scintillating fiber active target

    SciTech Connect

    Baumbaugh, B.; Bishop, J.; Gardner, R.W.; Mountain, R.J.; Ruchti, R.; Baumbaugh, A.; Knickerbocker, K.

    1987-10-01

    A monitor and control system has been designed, constructed and tested at Notre Dame for the purpose of controlling all aspects of a Scintillating Fiber Active Target system used in High Energy Physics Experimentation. The SFT Active Target system requires control of high voltages, gating, trigger counters, and monitoring. In addition, it resides in a radioactive area with very limited access. The control system uses a Leading Edge microcomputer, two specialized Z80-based processors, associated DACs, ADCs, discrete semiconductors, linear ICs, and TTL and MECL logic. All of the hardware and software is custom-built; its design and performance is discussed. 5 refs., 4 figs.

  13. Product characteristics from the torrefaction of oil palm fiber pellets in inert and oxidative atmospheres.

    PubMed

    Chen, Wei-Hsin; Zhuang, Yi-Qing; Liu, Shih-Hsien; Juang, Tarng-Tzuen; Tsai, Chi-Ming

    2016-01-01

    The aim of this work was to study the characteristics of solid and liquid products from the torrefaction of oil palm fiber pellets (OPFP) in inert and oxidative environments. The torrefaction temperature and O2 concentration in the carrier gas were in the ranges of 275-350°C and 0-10 vol%, respectively, while the torrefaction duration was 30 min. The oxidative torrefaction of OPFP at 275°C drastically intensified the HHV of the biomass when compared to the non-oxidative torrefaction. OPFP torrefied at 300°C is recommended to upgrade the biomass, irrespective of the atmosphere. The HHV of condensed liquid was between 10.1 and 13.2 MJ kg(-)(1), and was promoted to 23.2-28.7 MJ kg(-)(1) following dewatering. This accounts for 92-139% improvement in the calorific value of the liquid. This reveals that the recovery of condensed liquid with dewatering is able to enhance the energy efficiency of a torrefaction system. PMID:26346262

  14. Nickel oxide and molybdenum oxide thin films for infrared imaging prepared by biased target ion-beam deposition

    NASA Astrophysics Data System (ADS)

    Jin, Yao; Saint John, David; Jackson, Tom N.; Horn, Mark W.

    2014-06-01

    Vanadium oxide (VOx) thin films have been intensively used as sensing materials for microbolometers. VOx thin films have good bolometric properties such as low resistivity, high negative temperature coefficient of resistivity (TCR) and low 1/f noise. However, the processing controllability of VOx fabrication is difficult due to the multiple valence states of vanadium. In this study, metal oxides such as nickel oxide (NiOx) and molybdenum oxide (MoOx) thin films have been investigated as possible new microbolometer sensing materials with improved process controllability. Nickel oxide and molybdenum oxide thin films were prepared by reactive sputtering of nickel and molybdenum metal targets in a biased target ion beam deposition tool. In this deposition system, the Ar+ ion energy (typically lower than 25 eV) and the target bias voltage can be independently controlled since ions are remotely generated. A residual gas analyzer (RGA) is used to precisely control the oxygen partial pressure. A real-time spectroscopic ellipsometry is used to monitor the evolution of microstructure and properties of deposited oxides during growth and post-deposition. The properties of deposited oxide thin films depend on processing parameters. The resistivity of the NiOx thin films is in the range of 0.5 to approximately 100 ohm-cm with a TCR from -2%/K to -3.3%/K, where the resistivity of MoOx is between 3 and 2000 ohm-cm with TCR from -2.1%/K to -3.2%/K. We also report on the thermal stability of these deposited oxide thin films.

  15. Oxidation of alloys targeted for advanced steam turbines

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.; Alman, D.E.

    2006-03-12

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.

  16. Oxidative Stress and Response to Thymidylate Synthase-Targeted Antimetabolites.

    PubMed

    Ozer, Ufuk; Barbour, Karen W; Clinton, Sarah A; Berger, Franklin G

    2015-12-01

    Thymidylate synthase (TYMS; EC 2.1.1.15) catalyzes the reductive methylation of 2'-deoxyuridine-5'-monophosphate (dUMP) by N(5),N(10)-methyhlenetetrahydrofolate, forming dTMP for the maintenance of DNA replication and repair. Inhibitors of TYMS have been widely used in the treatment of neoplastic disease. A number of fluoropyrimidine and folate analogs have been developed that lead to inhibition of the enzyme, resulting in dTMP deficiency and cell death. In the current study, we have examined the role of oxidative stress in response to TYMS inhibitors. We observed that intracellular reactive oxygen species (ROS) concentrations are induced by these inhibitors and promote apoptosis. Activation of the enzyme NADPH oxidase (NOX), which catalyzes one-electron reduction of O2 to generate superoxide (O2 (●-)), is a significant source of increased ROS levels in drug-treated cells. However, gene expression profiling revealed a number of other redox-related genes that may contribute to ROS generation. TYMS inhibitors also induce a protective response, including activation of the transcription factor nuclear factor E2-related factor 2 (NRF2), a critical mediator of defense against oxidative and electrophilic stress. Our results show that exposure to TYMS inhibitors induces oxidative stress that leads to cell death, while simultaneously generating a protective response that may underlie resistance against such death. PMID:26443810

  17. Fiber-based Coherent Lidar for Target Ranging, Velocimetry, and Atmospheric Wind Sensing

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Pierrottet, Diego

    2006-01-01

    By employing a combination of optical heterodyne and linear frequency modulation techniques and utilizing state-of-the-art fiber optic technologies, highly efficient, compact and reliable lidar suitable for operation in a space environment is being developed.

  18. Metabolomics reveals that carnitine palmitoyltransferase-1 is a novel target for oxidative inactivation in human cells.

    PubMed

    Setoyama, Daiki; Fujimura, Yoshinori; Miura, Daisuke

    2013-12-01

    Oxidative dysfunction in the metabolism has long been implicated in diverse biological disorders. Although a substantial number of metabolic enzymes are targeted for inactivation by oxidative stress, identifying those targets remains difficult due to a lack of comprehensive observations of the metabolism acting through the stress response. We herein developed a metabolomics strategy using integrative liquid chromatography-mass spectrometry (LC-MS) and observing rapid metabolomic changes in response to hydrogen peroxide (H2 O2 )-induced oxidative stress in HeLa cells. Among the many metabolite changes detected, the most characteristic metabolites uniquely indicated carnitine palmitoyltransferase-1 (CPT1), the critical enzyme for mitochondrial β-oxidation of long-chain fatty acids, to be a target for oxidative inactivation. We showed that the enzymatic activity of CPT1 significantly declined by H2 O2 in several human cells. Interestingly, the inactivation was shown to be a direct effect of H2 O2 in vitro, but substantially occurred when cells were cultured with some reagents that generate reactive oxygen species (ROS). Thus, our results suggest the generality of CPT1 inhibition under various stress conditions associated with ROS generation, providing an insight into a mechanism for oxidative dysfunction in mitochondrial metabolism. Our metabolome data additionally suggest that certain methyltransferase(s) may be targets of oxidative stress as well. PMID:24118240

  19. Oxidation of SiC Fiber-Reinforced SiC Matrix Composites with a BN Interphase

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth; Boyd, Meredith K.

    2010-01-01

    SiC-fiber reinforced SiC matrix composites with a BN interphase were oxidized in reduced oxygen partial pressures of oxygen to simulate the environment for hypersonic vehicle leading edge applications. The constituent fibers as well as composite coupons were oxidized in oxygen partial pressures ranging from 1000 ppm O2 to 5% O2 balance argon. Exposure temperatures ranged from 816 C to 1353 C (1500 F to 2450 F). The oxidation kinetics of the coated fibers were monitored by thermogravimetric analysis (TGA). An initial rapid transient weight gain was observed followed by parabolic kinetics. Possible mechanisms for the transient oxidation are discussed. One edge of the composite coupon seal coat was ground off to simulate damage to the composite which allowed oxygen ingress to the interior of the composite. Oxidation kinetics of the coupons were characterized by scanning electron microscopy since the weight changes were minimal. It was found that sealing of the coupon edge by silica formation occurred. Differences in the amount and morphology of the sealing silica as a function of time, temperature and oxygen partial pressure are discussed. Implications for use of these materials for hypersonic vehicle leading edge materials are summarized.

  20. Atheroprotective Effect of Oleoylethanolamide (OEA) Targeting Oxidized LDL

    PubMed Central

    Wu, Huijuan; Li, Long; Huang, Rui; Zhu, Yueyong; Qiu, Yan; Fu, Jin; Ren, Jie; Zhu, Chenggang

    2014-01-01

    Dietary fat-derived lipid oleoylethanolamide (OEA) has shown to modulate lipid metabolism through a peroxisome proliferator-activated receptor-alpha (PPAR-α)-mediated mechanism. In our study, we further demonstrated that OEA, as an atheroprotective agent, modulated the atherosclerotic plaques development. In vitro studies showed that OEA antagonized oxidized LDL (ox-LDL)-induced vascular endothelial cell proliferation and vascular smooth muscle cell migration, and suppressed lipopolysaccharide (LPS)-induced LDL modification and inflammation. In vivo studies, atherosclerosis animals were established using balloon-aortic denudation (BAD) rats and ApoE-/- mice fed with high-caloric diet (HCD) for 17 or 14 weeks respectively, and atherosclerotic plaques were evaluated by oil red staining. The administration of OEA (5 mg/kg/day, intraperitoneal injection, i.p.) prevented or attenuated the formation of atherosclerotic plaques in HCD-BAD rats or HCD-ApoE−/− mice. Gene expression analysis of vessel tissues from these animals showed that OEA induced the mRNA expressions of PPAR-α and downregulated the expression of M-CFS, an atherosclerotic marker, and genes involved in oxidation and inflammation, including iNOS, COX-2, TNF-α and IL-6. Collectively, our results suggested that OEA exerted a pharmacological effect on modulating atherosclerotic plaque formation through the inhibition of LDL modification in vascular system and therefore be a potential candidate for anti-atherosclerosis drug. PMID:24465540

  1. Atheroprotective effect of oleoylethanolamide (OEA) targeting oxidized LDL.

    PubMed

    Fan, Angran; Wu, Xiaofeng; Wu, Huijuan; Li, Long; Huang, Rui; Zhu, Yueyong; Qiu, Yan; Fu, Jin; Ren, Jie; Zhu, Chenggang

    2014-01-01

    Dietary fat-derived lipid oleoylethanolamide (OEA) has shown to modulate lipid metabolism through a peroxisome proliferator-activated receptor-alpha (PPAR-α)-mediated mechanism. In our study, we further demonstrated that OEA, as an atheroprotective agent, modulated the atherosclerotic plaques development. In vitro studies showed that OEA antagonized oxidized LDL (ox-LDL)-induced vascular endothelial cell proliferation and vascular smooth muscle cell migration, and suppressed lipopolysaccharide (LPS)-induced LDL modification and inflammation. In vivo studies, atherosclerosis animals were established using balloon-aortic denudation (BAD) rats and ApoE(-/-) mice fed with high-caloric diet (HCD) for 17 or 14 weeks respectively, and atherosclerotic plaques were evaluated by oil red staining. The administration of OEA (5 mg/kg/day, intraperitoneal injection, i.p.) prevented or attenuated the formation of atherosclerotic plaques in HCD-BAD rats or HCD-ApoE(-/-) mice. Gene expression analysis of vessel tissues from these animals showed that OEA induced the mRNA expressions of PPAR-α and downregulated the expression of M-CFS, an atherosclerotic marker, and genes involved in oxidation and inflammation, including iNOS, COX-2, TNF-α and IL-6. Collectively, our results suggested that OEA exerted a pharmacological effect on modulating atherosclerotic plaque formation through the inhibition of LDL modification in vascular system and therefore be a potential candidate for anti-atherosclerosis drug. PMID:24465540

  2. Double layer oxidation resistant coating for carbon fiber reinforced silicon carbide matrix composites

    NASA Astrophysics Data System (ADS)

    Zheng, X. H.; Du, Y. G.; Xiao, J. Y.; Zhang, W. J.; Zhang, L. C.

    2009-01-01

    Double layer coatings, with celsian-Y 2SiO 5 as inner layer and Y 2Si 2O 7 as outer layer, were prepared by microwave sintering on the surface of carbon fiber reinforced silicon carbide matrix composite. Both celsian, Y 2SiO 5 and Y 2Si 2O 7 were synthesized by in situ method using BAS glass, Y 2O 3 and SiO 2 as staring materials. The sintering temperature was 1500 °C, and little damage was induced to the composite. The composition and micrograph of the fired coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The oxidation and thermal shock resistance of samples with doubled-layered coating were characterized at 1400 °C in air. After 150 min oxidation and thermal cycling between 1400 °C and room temperature for 15 times, the weight loss of double layer-coated sample was 1.22% and there were no cracks in the coating.

  3. A comparative study of carbon fiber-based microelectrodes for the measurement of nitric oxide in brain tissue.

    PubMed

    Santos, Ricardo M; Lourenço, Cátia F; Piedade, Ana P; Andrews, Rodney; Pomerleau, François; Huettl, Peter; Gerhardt, Greg A; Laranjinha, João; Barbosa, Rui M

    2008-12-01

    The measurement of Nitric oxide (NO) in real-time has been a major concern due to the involvement of this ubiquitous free radical modulator in several physiological and pathological pathways in tissues. Here we performed a study aiming at evaluating different types of carbon fibers, namely Textron, Amoco, Courtaulds and carbon nanotubes (University of Kentucky) covered with Nafion/o-phenylenediamine (o-PD) for NO measurement in terms of sensitivity, LOD, response time and selectivity against major potential interferents in the brain (ascorbate, nitrite and dopamine). The results indicate that, as compared with the other carbon fibers and nanotubes, Textron carbon fiber microelectrodes coated with two layers of Nafion and o-PD exhibited better characteristics for NO measurement as they are highly selective against ascorbate (>30,000:1), nitrite (>2000:1) and dopamine (>80:1). These coated Textron microelectrodes showed an average sensitivity of 341+/-120pA/microM and a detection limit of 16+/-11nM. The better performance of the Textron fibers is likely related to a stronger adhesion or more uniform coating of the Nafion and o-PD polymers to the fiber surface. In addition, the background current of the Textron carbon fibers is low, contributing to the excellent signal-to-noise for detection of NO. PMID:18657966

  4. Adhesive force measurement between HOPG and zinc oxide as an indicator for interfacial bonding of carbon fiber composites.

    PubMed

    Patterson, Brendan A; Galan, Ulises; Sodano, Henry A

    2015-07-22

    Vertically aligned zinc oxide (ZnO) nanowires have recently been utilized as an interphase to increase the interfacial strength of carbon fiber composites. It was shown that the interaction between the carbon fiber and the ZnO nanowires was a critical parameter in adhesion; however, fiber based testing techniques are dominated by local defects and cannot be used to effectively study the bonding interaction directly. Here, the strength of the interface between ZnO and graphitic carbon is directly measured with atomic force microscopy (AFM) using oxygen plasma treated highly oriented pyrolytic graphite (HOPG) and an AFM tip coated with ZnO nanoparticles. X-ray photoelectron spectroscopy analysis is used to compare the surface chemistry of HOPG and carbon fiber and to quantify the presence of various oxygen functional groups. An indirect measurement of the interfacial strength is then performed through single fiber fragmentation testing (SFF) on functionalized carbon fibers coated with ZnO nanowires to validate the AFM measurements. The SFF and AFM methods showed the same correlation, demonstrating the capacity of the AFM method to study the interfacial properties in composite materials. Additionally, the chemical interactions between oxygen functional groups and the ionic structure of ZnO suggest that intermolecular forces at the interface are responsible for the strong interface. PMID:26107931

  5. Thermo-oxidative stability studies of PMR-15 polymer matrix composites reinforced with various continuous fibers

    NASA Technical Reports Server (NTRS)

    Bowles, Kenneth J.

    1990-01-01

    An experimental study was conducted to measure the thermooxidative stability of PMR-15 composites reinforced with various fibers and to observe differences in the way they degrade in air. The fibers studied include graphite and the thermally stable Nicalon and Nextel ceramic fibers. Weight-loss rates for the different composites were assessed as a function of mechanical properties, specimen geometry, fiber sizing, and interfacial bond strength. Differences were observed in rates of weight loss, matrix cracking, geometry dependency, and fiber sizing effects. It was shown that Celion 6000 fiber-reinforced composites do not exhibit a straight-line Arrhenius relationship at temperatures above 316 C.

  6. Biodistribution of antibody-targeted and non-targeted iron oxide nanoparticles in a breast cancer mouse model

    NASA Astrophysics Data System (ADS)

    Tate, Jennifer A.; Kett, Warren; NDong, Christian; Griswold, Karl E.; Hoopes, P. Jack

    2013-02-01

    Iron oxide nanoparticle (IONP) hyperthermia is a novel therapeutic strategy currently under consideration for the treatment of various cancer types. Systemic delivery of IONP followed by non-invasive activation via a local alternating magnetic field (AMF) results in site-specific energy deposition in the IONP-containing tumor. Targeting IONP to the tumor using an antibody or antibody fragment conjugated to the surface may enhance the intratumoral deposition of IONP and is currently being pursued by many nanoparticle researchers. This strategy, however, is subject to a variety of restrictions in the in vivo environment, where other aspects of IONP design will strongly influence the biodistribution. In these studies, various targeted IONP are compared to non-targeted controls. IONP were injected into BT-474 tumor-bearing NSG mice and tissues harvested 24hrs post-injection. Results indicate no significant difference between the various targeted IONP and the non-targeted controls, suggesting the IONP were prohibitively-sized to incur tumor penetration. Additional strategies are currently being pursued in conjuncture with targeted particles to increase the intratumoral deposition.

  7. Free radical activity of industrial fibers: role of iron in oxidative stress and activation of transcription factors.

    PubMed Central

    Gilmour, P S; Brown, D M; Beswick, P H; MacNee, W; Rahman, I; Donaldson, K

    1997-01-01

    We studied asbestos, vitreous fiber (MMVF10), and refractory ceramic fiber (RCF1) from the Thermal Insulation Manufacturers' Association fiber repository regarding the following: free radical damage to plasmid DNA, iron release, ability to deplete glutathione (GSH), and activate redox-sensitive transcription factors in macrophages. Asbestos had much more free radical activity than any of the man-made vitreous fibers. More Fe3+ was released than Fe2+ and more of both was released at pH 4.5 than at pH 7.2. Release of iron from the different fibers was generally not a good correlate of ability to cause free radical injury to the plasmid DNA. All fiber types caused some degree of oxidative stress, as revealed by depletion of intracellular GSH. Amosite asbestos upregulated nuclear binding of activator protein 1 transcription factor to a greater level than MMVF10 and RCF1; long-fiber amosite was the only fiber to enhance activation of the transcription factor nuclear factor kappa B (NF kappa B). The use of cysteine methyl ester and buthionine sulfoximine to modulate GSH suggested that GSH homeostasis was important in leading to activation of transcription factors. We conclude that the intrinsic free radical activity is the major determinant of transcription factor activation and therefore gene expression in alveolar macrophages. Although this was not related to iron release or ability to deplete macrophage GSH at 4 hr, GSH does play a role in activation of NF kappa B. Images Figure 1. Figure 5. A Figure 5. B Figure 6. A Figure 6. B PMID:9400744

  8. Hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction for measurement of ibuprofen and naproxen in hair and waste water samples.

    PubMed

    Rezaeifar, Zohreh; Es'haghi, Zarrin; Rounaghi, Gholam Hossein; Chamsaz, Mahmoud

    2016-09-01

    A new design of hyperbranched polyglycerol/graphene oxide nanocomposite reinforced hollow fiber solid/liquid phase microextraction (HBP/GO -HF-SLPME) coupled with high performance liquid chromatography used for extraction and determination of ibuprofen and naproxen in hair and waste water samples. The graphene oxide first synthesized from graphite powders by using modified Hummers approach. The surface of graphene oxide was modified using hyperbranched polyglycerol, through direct polycondensation with thionyl chloride. The ready nanocomposite later wetted by a few microliter of an organic solvent (1-octanol), and then applied to extract the target analytes in direct immersion sampling mode.After the extraction process, the analytes were desorbed with methanol, and then detected via high performance liquid chromatography (HPLC). The experimental setup is very simple and highly affordable. The main factors influencing extraction such as; feed pH, extraction time, aqueous feed volume, agitation speed, the amount of functionalized graphene oxide and the desorption conditions have been examined in detail. Under the optimized experimental conditions, linearity was observed in the range of 5-30,000ngmL(-1) for ibuprofen and 2-10,000ngmL(-1) for naproxen with correlation coefficients of 0.9968 and 0.9925, respectively. The limits of detection were 2.95ngmL(-1) for ibuprofen and 1.51ngmL(-1) for naproxen. The relative standard deviations (RSDs) were found to be less than 5% (n=5). PMID:27428449

  9. Fatty acid oxidation and carnitine palmitoyltransferase I: emerging therapeutic targets in cancer.

    PubMed

    Qu, Q; Zeng, F; Liu, X; Wang, Q J; Deng, F

    2016-01-01

    Tumor cells exhibit unique metabolic adaptations that are increasingly viewed as potential targets for novel and specific cancer therapies. Among these targets, the carnitine palmitoyltransferase system is responsible for delivering the long-chain fatty acid (FA) from cytoplasm into mitochondria for oxidation, where carnitine palmitoyltransferase I (CPTI) catalyzes the rate-limiting step of fatty acid oxidation (FAO). With increasing understanding of the crucial role had by fatty acid oxidation in cancer, CPTI has received renewed attention as a pivotal mediator in cancer metabolic mechanism. CPTI activates FAO and fuels cancer growth via ATP and NADPH production, constituting an essential part of cancer metabolism adaptation. Moreover, CPTI also functionally intertwines with other key pathways and factors to regulate gene expression and apoptosis of cancer cell. Here, we summarize recent findings and update the current understanding of FAO and CPTI in cancer and provide theoretical basis for this enzyme as an emerging potential molecular target in cancer therapeutic intervention. PMID:27195673

  10. Fatty acid oxidation and carnitine palmitoyltransferase I: emerging therapeutic targets in cancer

    PubMed Central

    Qu, Q; Zeng, F; Liu, X; Wang, Q J; Deng, F

    2016-01-01

    Tumor cells exhibit unique metabolic adaptations that are increasingly viewed as potential targets for novel and specific cancer therapies. Among these targets, the carnitine palmitoyltransferase system is responsible for delivering the long-chain fatty acid (FA) from cytoplasm into mitochondria for oxidation, where carnitine palmitoyltransferase I (CPTI) catalyzes the rate-limiting step of fatty acid oxidation (FAO). With increasing understanding of the crucial role had by fatty acid oxidation in cancer, CPTI has received renewed attention as a pivotal mediator in cancer metabolic mechanism. CPTI activates FAO and fuels cancer growth via ATP and NADPH production, constituting an essential part of cancer metabolism adaptation. Moreover, CPTI also functionally intertwines with other key pathways and factors to regulate gene expression and apoptosis of cancer cell. Here, we summarize recent findings and update the current understanding of FAO and CPTI in cancer and provide theoretical basis for this enzyme as an emerging potential molecular target in cancer therapeutic intervention. PMID:27195673

  11. Exogenous Nitric Oxide Suppresses in Vivo X-ray-Induced Targeted and Non-Targeted Effects in Zebrafish Embryos

    PubMed Central

    Kong, E.Y.; Yeung, W.K.; Chan, T.K.Y.; Cheng, S.H.; Yu, K.N.

    2016-01-01

    The present paper studied the X-ray-induced targeted effect in irradiated zebrafish embryos (Danio rerio), as well as a non-targeted effect in bystander naïve embryos partnered with irradiated embryos, and examined the influence of exogenous nitric oxide (NO) on these targeted and non-targeted effects. The exogenous NO was generated using an NO donor, S-nitroso-N-acetylpenicillamine (SNAP). The targeted and non-targeted effects, as well as the toxicity of the SNAP, were assessed using the number of apoptotic events in the zebrafish embryos at 24 h post fertilization (hpf) revealed through acridine orange (AO) staining. SNAP with concentrations of 20 and 100 µM were first confirmed to have no significant toxicity on zebrafish embryos. The targeted effect was mitigated in zebrafish embryos if they were pretreated with 100 µM SNAP prior to irradiation with an X-ray dose of 75 mGy but was not alleviated in zebrafish embryos if they were pretreated with 20 µM SNAP. On the other hand, the non-targeted effect was eliminated in the bystander naïve zebrafish embryos if they were pretreated with 20 or 100 µM SNAP prior to partnering with zebrafish embryos having been subjected to irradiation with an X-ray dose of 75 mGy. These findings revealed the importance of NO in the protection against damages induced by ionizing radiations or by radiation-induced bystander signals, and could have important impacts on development of advanced cancer treatment strategies. PMID:27529238

  12. Carbon fiber composite targets for nuclear fusion technology: a focused ion beam/scanning electron microscope investigation.

    PubMed

    Ghezzi, F; Magni, S; Milani, M; Tatti, F

    2007-01-01

    Carbon fiber composite (CFC) targets are investigated by a focused ion beam/scanning electron microscope (FIB/SEM) in a joint project aiming at the development of robust divertors in the International Thermonuclear Experimental Reactor (ITER). These mockups are exposed to a plasma that simulates the off-normal thermal loads foreseen for ITER and display a rich, puzzling impact scenario. Morphological elements are identified at the exposed surface and beneath it, and are examined in order to point out the relevant processes involved. Each technique adopted is discussed and evaluated. PMID:18200678

  13. Drug Targets for Oxidative Podocyte Injury in Diabetic Nephropathy

    PubMed Central

    Usman, Muhammad

    2015-01-01

    Diabetic nephropathy (DN) is one the most prevalent chronic complications of diabetes mellitus that affects as much as one-third of diabetic patients irrespective of the type of diabetes. Hyperglycemia is the key trigger for DN that initiates a number of microscopic and ultramicroscopic changes in kidney architecture. Microscopic changes include thickening of the glomerular basement membrane (GBM), tubular basement membrane (TBM), mesangial proliferation, arteriosclerosis, and glomerulotubular junction abnormalities (GTJA). Among the ultramicroscopic changes, effacement of podocytes and decrease in their density seem to be the centerpiece of DN pathogenesis. These changes in kidney architecture then produce functional deficits, such as microalbuminuria and decreased glomerular filtration rate (GFR). Among several mechanisms involved in inflicting damage to podocytes, injuries sustained by increased oxidative stress turns out to be the most important mechanism. Different variables that are included in increased production of reactive oxygen species (ROS) include a hyperglycemia-induced reduction in glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation via hyperglycemia, advanced glycation end products (AGEs), protein kinase C (PKC), and renin-angiotensin-aldosterone system (RAAS). Unfortunately, control of podocyte injury hasn’t received much attention as a treatment approach for DN. Therefore, this review article is mainly concerned with the exploration of various treatment options that might help in decreasing the podocyte injury, mainly by reducing the level of NADPH oxidase-mediated generation of ROS. This article concludes with a view that certain NADPH oxidase inhibitors, RAAS inhibitors, statins, antidiabetic drugs, and antioxidant vitamins might be useful in decreasing podocyte injury and resultant structural and functional kidney impairments in DN. PMID:26798569

  14. Drug Targets for Oxidative Podocyte Injury in Diabetic Nephropathy.

    PubMed

    Bhatti, Adnan Bashir; Usman, Muhammad

    2015-01-01

    Diabetic nephropathy (DN) is one the most prevalent chronic complications of diabetes mellitus that affects as much as one-third of diabetic patients irrespective of the type of diabetes. Hyperglycemia is the key trigger for DN that initiates a number of microscopic and ultramicroscopic changes in kidney architecture. Microscopic changes include thickening of the glomerular basement membrane (GBM), tubular basement membrane (TBM), mesangial proliferation, arteriosclerosis, and glomerulotubular junction abnormalities (GTJA). Among the ultramicroscopic changes, effacement of podocytes and decrease in their density seem to be the centerpiece of DN pathogenesis. These changes in kidney architecture then produce functional deficits, such as microalbuminuria and decreased glomerular filtration rate (GFR). Among several mechanisms involved in inflicting damage to podocytes, injuries sustained by increased oxidative stress turns out to be the most important mechanism. Different variables that are included in increased production of reactive oxygen species (ROS) include a hyperglycemia-induced reduction in glutathione (GSH), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation via hyperglycemia, advanced glycation end products (AGEs), protein kinase C (PKC), and renin-angiotensin-aldosterone system (RAAS). Unfortunately, control of podocyte injury hasn't received much attention as a treatment approach for DN. Therefore, this review article is mainly concerned with the exploration of various treatment options that might help in decreasing the podocyte injury, mainly by reducing the level of NADPH oxidase-mediated generation of ROS. This article concludes with a view that certain NADPH oxidase inhibitors, RAAS inhibitors, statins, antidiabetic drugs, and antioxidant vitamins might be useful in decreasing podocyte injury and resultant structural and functional kidney impairments in DN. PMID:26798569

  15. The Immature Fiber Mutant Phenotype of Cotton (Gossypium hirsutum) Is Linked to a 22-bp Frame-Shift Deletion in a Mitochondria Targeted Pentatricopeptide Repeat Gene

    PubMed Central

    Thyssen, Gregory N.; Fang, David D.; Zeng, Linghe; Song, Xianliang; Delhom, Christopher D.; Condon, Tracy L.; Li, Ping; Kim, Hee Jin

    2016-01-01

    Cotton seed trichomes are the most important source of natural fibers globally. The major fiber thickness properties influence the price of the raw material, and the quality of the finished product. The recessive immature fiber (im) gene reduces the degree of fiber cell wall thickening by a process that was previously shown to involve mitochondrial function in allotetraploid Gossypium hirsutum. Here, we present the fine genetic mapping of the im locus, gene expression analysis of annotated proteins near the locus, and association analysis of the linked markers. Mapping-by-sequencing identified a 22-bp deletion in a pentatricopeptide repeat (PPR) gene that is completely linked to the immature fiber phenotype in 2837 F2 plants, and is absent from all 163 cultivated varieties tested, although other closely linked marker polymorphisms are prevalent in the diversity panel. This frame-shift mutation results in a transcript with two long open reading frames: one containing the N-terminal transit peptide that targets mitochondria, the other containing only the RNA-binding PPR domains, suggesting that a functional PPR protein cannot be targeted to mitochondria in the im mutant. Taken together, these results suggest that PPR gene Gh_A03G0489 is involved in the cotton fiber wall thickening process, and is a promising candidate gene at the im locus. Our findings expand our understanding of the molecular mechanisms that modulate cotton fiber fineness and maturity, and may facilitate the development of cotton varieties with superior fiber attributes. PMID:27172184

  16. The Immature Fiber Mutant Phenotype of Cotton (Gossypium hirsutum) Is Linked to a 22-bp Frame-Shift Deletion in a Mitochondria Targeted Pentatricopeptide Repeat Gene.

    PubMed

    Thyssen, Gregory N; Fang, David D; Zeng, Linghe; Song, Xianliang; Delhom, Christopher D; Condon, Tracy L; Li, Ping; Kim, Hee Jin

    2016-01-01

    Cotton seed trichomes are the most important source of natural fibers globally. The major fiber thickness properties influence the price of the raw material, and the quality of the finished product. The recessive immature fiber (im) gene reduces the degree of fiber cell wall thickening by a process that was previously shown to involve mitochondrial function in allotetraploid Gossypium hirsutum Here, we present the fine genetic mapping of the im locus, gene expression analysis of annotated proteins near the locus, and association analysis of the linked markers. Mapping-by-sequencing identified a 22-bp deletion in a pentatricopeptide repeat (PPR) gene that is completely linked to the immature fiber phenotype in 2837 F2 plants, and is absent from all 163 cultivated varieties tested, although other closely linked marker polymorphisms are prevalent in the diversity panel. This frame-shift mutation results in a transcript with two long open reading frames: one containing the N-terminal transit peptide that targets mitochondria, the other containing only the RNA-binding PPR domains, suggesting that a functional PPR protein cannot be targeted to mitochondria in the im mutant. Taken together, these results suggest that PPR gene Gh_A03G0489 is involved in the cotton fiber wall thickening process, and is a promising candidate gene at the im locus. Our findings expand our understanding of the molecular mechanisms that modulate cotton fiber fineness and maturity, and may facilitate the development of cotton varieties with superior fiber attributes. PMID:27172184

  17. Oxidation of Carbon Fibers in a Cracked Ceramic Matrix Composite Modeled as a Function of Temperature

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.; Cawley, James D.; Eckel, Andrew J.

    2003-01-01

    The oxidation model simulates the oxidation of the reinforcing carbon fibers within a ceramic matrix composite material containing as-fabricated microcracks. The physics-based oxidation model uses theoretically and experimentally determined variables as input for the model. The model simulates the ingress of oxygen through microcracks into a two-dimensional plane within the composite material. Model input includes temperature, oxygen concentration, the reaction rate constant, the diffusion coefficient, and the crack opening width as a function of the mechanical and thermal loads. The model is run in an iterative process for a two-dimensional grid system in which oxygen diffuses through the porous and cracked regions of the material and reacts with carbon in short time steps. The model allows the local oxygen concentrations and carbon volumes from the edge to the interior of the composite to be determined over time. Oxidation damage predicted by the model was compared with that observed from microstructural analysis of experimentally tested composite material to validate the model for two temperatures of interest. When the model is run for low-temperature conditions, the kinetics are reaction controlled. Carbon and oxygen reactions occur relatively slowly. Therefore, oxygen can bypass the carbon near the outer edge and diffuse into the interior so that it saturates the entire composite at relatively high concentrations. The kinetics are limited by the reaction rate between carbon and oxygen. This results in an interior that has high local concentrations of oxygen and a similar amount of consumed carbon throughout the cross section. When the model is run for high-temperature conditions, the kinetics are diffusion controlled. Carbon and oxygen reactions occur very quickly. The carbon consumes oxygen as soon as it is supplied. The kinetics are limited by the relatively slow rate at which oxygen is supplied in comparison to the relatively fast rate at which carbon and

  18. Structural characterization and photocatalytic activity of hollow binary ZrO{sub 2}/TiO{sub 2} oxide fibers

    SciTech Connect

    Wu Baochao; Yuan Rusheng Fu Xianzhi

    2009-03-15

    The formation of hollow binary ZrO{sub 2}/TiO{sub 2} oxide fibers using mixed precursor solutions was achieved by activated carbon fibers templating technique combined with solvothermal process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N{sub 2} adsorption, X-ray photoelectron spectroscopy (XPS), UV-vis, and infrared (IR) spectroscopy. The binary oxide system shows the anatase-type TiO{sub 2} and tetragonal phase of ZrO{sub 2}, and the introduction of ZrO{sub 2} notably inhibits the growth of TiO{sub 2} nanocrystallites. Although calcined at 575 deg. C, all hollow ZrO{sub 2}/TiO{sub 2} fibers exhibit higher surface areas (>113 m{sup 2}/g) than pure TiO{sub 2} hollow fibers. The Pyridine adsorption on ZrO{sub 2}/TiO{sub 2} sample indicates the presence of stronger surface acid sites. Such properties bring about that the binary oxide system possesses higher efficiency and durable activity stability for photodegradation of gaseous ethylene and trichloromethane than P25 TiO{sub 2}. In addition, the macroscopic felt form for the resulting materials is more beneficial for practical applications than traditional catalysts forms. - Graphical abstract: The final ZrO{sub 2}/TiO{sub 2} products composed of hollow fibers are in the form of felt on the centimeter scale and possess certain strength and flexibleness. Moreover, they exhibit excellent efficiency and durable activity stability for photodegradation of gaseous ethylene and trichloromethane, reaching about 136% and 387% of the P25 activity after 10 h, respectively.

  19. Targeting oxidant-dependent mechanisms for the treatment of COPD and its comorbidities.

    PubMed

    Bernardo, Ivan; Bozinovski, Steven; Vlahos, Ross

    2015-11-01

    Chronic obstructive pulmonary disease (COPD) is an incurable global health burden and is characterised by progressive airflow limitation and loss of lung function. In addition to the pulmonary impact of the disease, COPD patients often develop comorbid diseases such as cardiovascular disease, skeletal muscle wasting, lung cancer and osteoporosis. One key feature of COPD, yet often underappreciated, is the contribution of oxidative stress in the onset and development of the disease. Patients experience an increased burden of oxidative stress due to the combined effects of excess reactive oxygen species (ROS) and nitrogen species (RNS) generation, antioxidant depletion and reduced antioxidant enzyme activity. Currently, there is a lack of effective treatments for COPD, and an even greater lack of research regarding interventions that treat both COPD and its comorbidities. Due to the involvement of oxidative stress in the pathogenesis of COPD and many of its comorbidities, a unique therapeutic opportunity arises where the treatment of a multitude of diseases may be possible with only one therapeutic target. In this review, oxidative stress and the roles of ROS/RNS in the context of COPD and comorbid cardiovascular disease, skeletal muscle wasting, lung cancer, and osteoporosis are discussed and the potential for therapeutic benefit of anti-oxidative treatment in these conditions is outlined. Because of the unique interplay between oxidative stress and these diseases, oxidative stress represents a novel target for the treatment of COPD and its comorbidities. PMID:26297673

  20. Understanding the Impact of Poly(ethylene oxide) on the Assembly of Lignin in Solution toward Improved Carbon Fiber Production.

    PubMed

    Imel, Adam E; Naskar, Amit K; Dadmun, Mark D

    2016-02-10

    Carbon fiber produced from lignin has recently become an industrial scalable product with applications ranging from thermal insulation to reinforcing automobile bodies. Previous research has shown that mixing 1-2 wt %, of poly(ethylene oxide) (PEO) with the lignin before fiber formation can enhance the properties of the final carbon fibers. The research reported here determines the impact of adding PEO to a lignin solution on its assembly, focusing on the role of the lignin structure on this assembly process. Results indicate the addition of PEO anisotropically directs the self-assembly of the hardwood and softwood lignin by lengthening the cylindrical building blocks that make up the larger global aggregates. On the other hand, results from an annual lignin exhibit a shapeless, more complex structure with a unique dependence on the PEO loading. These results are consistent with improved carbon fibers from solutions of lignin that include PEO, as the local ordering and directed assembly will inhibit the formation of defects during the carbon fiber fabrication process. PMID:26756927

  1. Effects of working pressure on physical properties of tungsten-oxide thin films sputtered from oxide target

    SciTech Connect

    Riech, I.; Acosta, M.; Pena, J. L.; Bartolo-Perez, P.

    2010-03-15

    Tungsten-oxide films were deposited on glass substrates from a metal-oxide target by nonreactive radio-frequency sputtering. The authors have studied the effect that changing Ar gas pressure has on the electrical, optical, and chemical composition in the thin films. Resistivity of WO{sub 3} changed ten orders of magnitude with working gas pressure values from 20 to 80 mTorr. Thin films deposited at 20 mTorr of Ar sputtering pressure showed lower resistivity and optical transmittance. X-ray photoelectron spectroscopy (XPS) measurements revealed similar chemical composition for all samples irrespective of Ar pressure used. However, XPS analyses of the evolution of W 4f and O 1s peaks indicated a mixture of oxides dependent on the Ar pressure used during deposition.

  2. Te/Pt nanonetwork modified carbon fiber microelectrodes for methanol oxidation

    NASA Astrophysics Data System (ADS)

    Tsai, Hsiang-Yu; Shih, Zih-Yu; Lin, Zong-Hong; Chang, Huan-Tsung

    2013-05-01

    Te/Pt nanonetwork-decorated carbon fiber microelectrodes (CFMEs) have been fabricated and employed as anodic catalysts in a direct methanol fuel cell (DMFC). Te nanowires were prepared from tellurite ions (TeO32-) through a seed-mediated growth process and were deposited onto CFMEs to form three-dimensional Te nanonetworks. The Te nanonetworks then acted as a framework and reducing agent to reduce PtCl62- ions to form Te/Pt through a galvanic replacement reaction, leading to the formation of Te/PtCFMEs. By controlling the reaction time, the amount of Pt and morphology of Te/Pt nanonetworks were controlled, leading to various degrees of electrocatalytic activity. The Te/PtCFMEs provide a high electrochemical active surface area (129.2 m2 g-1), good catalytic activity (1.2 A mg-1), high current density (20.0 mA cm-2), long durability, and tolerance toward the poisoning species for methanol oxidation in 0.5 M sulfuric acid containing 1 M methanol. We have further demonstrated an enhanced current density by separately using 3 and 5 Te/PtCFMEs. Our results show that the low-cost, stable, and effective Te/PtCFMEs have great potential in the fabrication of cost-effective fuel cells.

  3. Te/Pt nanonetwork modified carbon fiber microelectrodes for methanol oxidation.

    PubMed

    Tsai, Hsiang-Yu; Shih, Zih-Yu; Lin, Zong-Hong; Chang, Huan-Tsung

    2013-05-17

    Te/Pt nanonetwork-decorated carbon fiber microelectrodes (CFMEs) have been fabricated and employed as anodic catalysts in a direct methanol fuel cell (DMFC). Te nanowires were prepared from tellurite ions (TeO3(2-)) through a seed-mediated growth process and were deposited onto CFMEs to form three-dimensional Te nanonetworks. The Te nanonetworks then acted as a framework and reducing agent to reduce PtCl6(2-) ions to form Te/Pt through a galvanic replacement reaction, leading to the formation of Te/PtCFMEs. By controlling the reaction time, the amount of Pt and morphology of Te/Pt nanonetworks were controlled, leading to various degrees of electrocatalytic activity. The Te/PtCFMEs provide a high electrochemical active surface area (129.2 m(2) g(-1)), good catalytic activity (1.2 A mg(-1)), high current density (20.0 mA cm(-2)), long durability, and tolerance toward the poisoning species for methanol oxidation in 0.5 M sulfuric acid containing 1 M methanol. We have further demonstrated an enhanced current density by separately using 3 and 5 Te/PtCFMEs. Our results show that the low-cost, stable, and effective Te/PtCFMEs have great potential in the fabrication of cost-effective fuel cells. PMID:23579734

  4. Increase of the deposition rate in reactive sputtering of metal oxides using a ceramic nitride target

    SciTech Connect

    Severin, D.; Wuttig, M.; Kappertz, O.; Nyberg, T.; Berg, S.; Pflug, A.

    2009-05-01

    We present a method to eliminate hysteresis effects and to increase the deposition rate for the reactive sputtering of metal oxides. This is achieved by using a ceramic nitride target in an argon-oxygen atmosphere. Although the use of a ceramic nitride target leads to pronounced changes of the processing characteristics, incorporation of nitrogen into the growing film is very small. These observations can be theoretically predicted using an extension of Berg's model [S. Berg and T. Nyberg, Thin Solid Films 476, 215 (2005)] to two different reactive gases and a compound target.

  5. Maximal oxygen uptake is proportional to muscle fiber oxidative capacity, from chronic heart failure patients to professional cyclists.

    PubMed

    van der Zwaard, Stephan; de Ruiter, Jo C; Noordhof, Dionne A; Sterrenburg, Renske; Bloemers, Frank W; de Koning, Jos J; Jaspers, Richard T; van der Laarse, Willem J

    2016-09-01

    V̇o2 max during whole body exercise is presumably constrained by oxygen delivery to mitochondria rather than by mitochondria's ability to consume oxygen. Humans and animals have been reported to exploit only 60-80% of their mitochondrial oxidative capacity at maximal oxygen uptake (V̇o2 max). However, ex vivo quantification of mitochondrial overcapacity is complicated by isolation or permeabilization procedures. An alternative method for estimating mitochondrial oxidative capacity is via enzyme histochemical quantification of succinate dehydrogenase (SDH) activity. We determined to what extent V̇o2 max attained during cycling exercise differs from mitochondrial oxidative capacity predicted from SDH activity of vastus lateralis muscle in chronic heart failure patients, healthy controls, and cyclists. V̇o2 max was assessed in 20 healthy subjects and 28 cyclists, and SDH activity was determined from biopsy cryosections of vastus lateralis using quantitative histochemistry. Similar data from our laboratory of 14 chronic heart failure patients and 6 controls were included. Mitochondrial oxidative capacity was predicted from SDH activity using estimated skeletal muscle mass and the relationship between ex vivo fiber V̇o2 max and SDH activity of isolated single muscle fibers and myocardial trabecula under hyperoxic conditions. Mitochondrial oxidative capacity predicted from SDH activity was related (r(2) = 0.89, P < 0.001) to V̇o2 max measured during cycling in subjects with V̇o2 max ranging from 9.8 to 79.0 ml·kg(-1)·min(-1) V̇o2 max measured during cycling was on average 90 ± 14% of mitochondrial oxidative capacity. We conclude that human V̇o2 max is related to mitochondrial oxidative capacity predicted from skeletal muscle SDH activity. Mitochondrial oxidative capacity is likely marginally limited by oxygen supply to mitochondria. PMID:27445298

  6. Targeting multiple types of tumors using NKG2D-coated iron oxide nanoparticles

    PubMed Central

    Wu, Ming-Ru; Cook, W. James; Zhang, Tong; Sentman, Charles L.

    2015-01-01

    Iron oxide nanoparticles (IONPs) hold great potential for cancer therapy. Actively targeting IONPs to tumor cells can further increase therapeutic efficacy and decrease off-target side effects. To target tumor cells, a natural killer (NK) cell activating receptor, NKG2D, was utilized to develop pan-tumor targeting IONPs. NKG2D ligands are expressed on many tumor types and its ligands are not found on most normal tissues under steady state conditions. The data showed that mouse and human fragment crystallizable (Fc) -fusion NKG2D (Fc-NKG2D) coated IONPs (NKG2D/NPs) can target multiple NKG2D ligand positive tumor types in vitro in a dose dependent manner by magnetic cell sorting. Tumor targeting effect was robust even under a very low tumor cell to normal cell ratio and targeting efficiency correlated with NKG2D ligand expression level on tumor cells. Furthermore, the magnetic separation platform utilized to test NKG2D/NP specificity has the potential to be developed into high throughput screening strategies to identify ideal fusion proteins or antibodies for targeting IONPs. In conclusion, NKG2D/NPs can be used to target multiple tumor types and magnetic separation platform can facilitate the proof-of-concept phase of tumor targeting IONP development. PMID:25371538

  7. Targeting multiple types of tumors using NKG2D-coated iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Ru; Cook, W. James; Zhang, Tong; Sentman, Charles L.

    2014-11-01

    Iron oxide nanoparticles (IONPs) hold great potential for cancer therapy. Actively targeting IONPs to tumor cells can further increase therapeutic efficacy and decrease off-target side effects. To target tumor cells, a natural killer (NK) cell activating receptor, NKG2D, was utilized to develop pan-tumor targeting IONPs. NKG2D ligands are expressed on many tumor types and its ligands are not found on most normal tissues under steady state conditions. The data showed that mouse and human fragment crystallizable (Fc)-fusion NKG2D (Fc-NKG2D) coated IONPs (NKG2D/NPs) can target multiple NKG2D ligand positive tumor types in vitro in a dose dependent manner by magnetic cell sorting. Tumor targeting effect was robust even under a very low tumor cell to normal cell ratio and targeting efficiency correlated with NKG2D ligand expression level on tumor cells. Furthermore, the magnetic separation platform utilized to test NKG2D/NP specificity has the potential to be developed into high throughput screening strategies to identify ideal fusion proteins or antibodies for targeting IONPs. In conclusion, NKG2D/NPs can be used to target multiple tumor types and magnetic separation platform can facilitate the proof-of-concept phase of tumor targeting IONP development.

  8. Chlorotoxin-conjugated graphene oxide for targeted delivery of an anticancer drug.

    PubMed

    Wang, Hao; Gu, Wei; Xiao, Ning; Ye, Ling; Xu, Qunyuan

    2014-01-01

    Current chemotherapy for glioma is rarely satisfactory due to low therapeutic efficiency and systemic side effects. We have developed a glioma-targeted drug delivery system based on graphene oxide. Targeted peptide chlorotoxin-conjugated graphene oxide (CTX-GO) sheets were successfully synthesized and characterized. Doxorubicin was loaded onto CTX-GO (CTX-GO/DOX) with high efficiency (570 mg doxorubicin per gram CTX-GO) via noncovalent interactions. Doxorubicin release was pH-dependent and showed sustained-release properties. Cytotoxicity experiments demonstrated that CTX-GO/DOX mediated the highest rate of death of glioma cells compared with free doxorubicin or graphene oxide loaded with doxorubicin only. Further, conjugation with chlorotoxin enhanced accumulation of doxorubicin within glioma cells. These findings indicate that CTX-GO is a promising platform for drug delivery and provide a rationale for developing a glioma-specific drug delivery system. PMID:24672236

  9. microRNAs: Emerging Targets Regulating Oxidative Stress in the Models of Parkinson's Disease

    PubMed Central

    Xie, Yangmei; Chen, Yinghui

    2016-01-01

    Parkinson's disease (PD) is the second most common neurodegenerative disorder. This chronic, progressive disease is characterized by loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and the presence of cytoplasmic inclusions called Lewy bodies (LBs) in surviving neurons. PD is attributed to a combination of environment and genetic factors, but the precise underlying molecular mechanisms remain elusive. Oxidative stress is generally recognized as one of the main causes of PD, and excessive reactive oxygen species (ROS) can lead to DA neuron vulnerability and eventual death. Several studies have demonstrated that small non-coding RNAs termed microRNAs (miRNAs) can regulate oxidative stress in vitro and in vivo models of PD. Relevant miRNAs involved in oxidative stress can prevent ROS-mediated damage to DA neurons, suggesting that specific miRNAs may be putative targets for novel therapeutic targets in PD. PMID:27445669

  10. Glycolytic-to-oxidative fiber-type switch and mTOR signaling activation are early-onset features of SBMA muscle modified by high-fat diet.

    PubMed

    Rocchi, Anna; Milioto, Carmelo; Parodi, Sara; Armirotti, Andrea; Borgia, Doriana; Pellegrini, Matteo; Urciuolo, Anna; Molon, Sibilla; Morbidoni, Valeria; Marabita, Manuela; Romanello, Vanina; Gatto, Pamela; Blaauw, Bert; Bonaldo, Paolo; Sambataro, Fabio; Robins, Diane M; Lieberman, Andrew P; Sorarù, Gianni; Vergani, Lodovica; Sandri, Marco; Pennuto, Maria

    2016-07-01

    Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by the expansion of a polyglutamine tract in the androgen receptor (AR). The mechanism by which expansion of polyglutamine in AR causes muscle atrophy is unknown. Here, we investigated pathological pathways underlying muscle atrophy in SBMA knock-in mice and patients. We show that glycolytic muscles were more severely affected than oxidative muscles in SBMA knock-in mice. Muscle atrophy was associated with early-onset, progressive glycolytic-to-oxidative fiber-type switch. Whole genome microarray and untargeted lipidomic analyses revealed enhanced lipid metabolism and impaired glycolysis selectively in muscle. These metabolic changes occurred before denervation and were associated with a concurrent enhancement of mechanistic target of rapamycin (mTOR) signaling, which induced peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC1α) expression. At later stages of disease, we detected mitochondrial membrane depolarization, enhanced transcription factor EB (TFEB) expression and autophagy, and mTOR-induced protein synthesis. Several of these abnormalities were detected in the muscle of SBMA patients. Feeding knock-in mice a high-fat diet (HFD) restored mTOR activation, decreased the expression of PGC1α, TFEB, and genes involved in oxidative metabolism, reduced mitochondrial abnormalities, ameliorated muscle pathology, and extended survival. These findings show early-onset and intrinsic metabolic alterations in SBMA muscle and link lipid/glucose metabolism to pathogenesis. Moreover, our results highlight an HFD regime as a promising approach to support SBMA patients. PMID:26971100

  11. Lipidomics identifies cardiolipin oxidation as a mitochondrial target for redox therapy of brain injury.

    PubMed

    Ji, Jing; Kline, Anthony E; Amoscato, Andrew; Samhan-Arias, Alejandro K; Sparvero, Louis J; Tyurin, Vladimir A; Tyurina, Yulia Y; Fink, Bruno; Manole, Mioara D; Puccio, Ava M; Okonkwo, David O; Cheng, Jeffrey P; Alexander, Henry; Clark, Robert S B; Kochanek, Patrick M; Wipf, Peter; Kagan, Valerian E; Bayır, Hülya

    2012-10-01

    The brain contains a highly diversified complement of molecular species of a mitochondria-specific phospholipid, cardiolipin, which, because of its polyunsaturation, can readily undergo oxygenation. Using global lipidomics analysis in experimental traumatic brain injury (TBI), we found that TBI was accompanied by oxidative consumption of polyunsaturated cardiolipin and the accumulation of more than 150 new oxygenated molecular species of cardiolipin. RNAi-based manipulations of cardiolipin synthase and cardiolipin levels conferred resistance to mechanical stretch, an in vitro model of traumatic neuronal injury, in primary rat cortical neurons. By applying a brain-permeable mitochondria-targeted electron scavenger, we prevented cardiolipin oxidation in the brain, achieved a substantial reduction in neuronal death both in vitro and in vivo, and markedly reduced behavioral deficits and cortical lesion volume. We conclude that cardiolipin oxygenation generates neuronal death signals and that prevention of it by mitochondria-targeted small molecule inhibitors represents a new target for neuro-drug discovery. PMID:22922784

  12. Meat quality, oxidative stability and blood parameters from Graylag geese offered alternative fiber sources in growing period.

    PubMed

    He, L W; Meng, Q X; Li, D Y; Zhang, Y W; Ren, L P

    2015-04-01

    The effects of dietary fiber sources on the meat quality, oxidative stability, and blood parameters of growing Graylag geese (28-112d) were investigated. The birds were randomly allocated into 4 treatments, of which dietary fiber was mainly from corn straw silage (CSS), steam-exploded corn straw (SECS), steam-exploded wheat straw (SEWS), and steam-exploded rice straw (SERS). No influence (P>0.05) on the basic chemical components, oxidative stability, or organoleptic traits of muscle were observed, except that birds fed SECS had a higher (P<0.05) protein proportion than those fed CSS or SERS, and CSS increased (P<0.01) the cholesterol content when compared to SEWS or SERS. Regarding fatty acid profile in meat, CSS and SECS increased (P<0.01) the proportion of C18:2n6t and decreased that of C21:0 and C22:0 when compared to the others. The birds fed SERS had a higher (P<0.05) proportion of C20:0 and C22:0 than the others, a higher proportion of C20:5n3, n-3 fatty acids, Δ-9 desaturase (18) index compared to those fed CSS or SECS, and a lower (P<0.01) proportion of C20:1n9 than those fed SECS or SEWS. Additionally, SEWS resulted in a higher (P<0.01) proportion of C20:2 when compared to the others. In conclusion, these fibers affect just the protein proportion, cholesterol content, and fatty acid profile of breast muscle, along with the concentration of TG and MDA in blood, but not the other characteristics. No superior fiber source exists with respect to meat quality, suggesting that Graylag geese feeding should make the most economically of the convenient fiber source with appropriate pretreatment. PMID:25717090

  13. Method of producing superconducting fibers of bismuth strontium calcium copper oxide (Bi(2212) and Bi(2223))

    DOEpatents

    Schwartzkopf, Louis A.

    1991-10-01

    Fibers of Bi(2212) have been produce by pendant drop melt extraction. This technique involves the end of a rod of Bi(2212) melted with a hydrogen-oxygen torch, followed by lowering onto the edge of a spinning wheel. The fibers are up to 15 cm in length with the usual lateral dimensions, ranging from 20 um to 30 um. The fibers require a heat treatment to make them superconducting.

  14. Long circulating reduced graphene oxide-iron oxide nanoparticles for efficient tumor targeting and multimodality imaging

    NASA Astrophysics Data System (ADS)

    Xu, Cheng; Shi, Sixiang; Feng, Liangzhu; Chen, Feng; Graves, Stephen A.; Ehlerding, Emily B.; Goel, Shreya; Sun, Haiyan; England, Christopher G.; Nickles, Robert J.; Liu, Zhuang; Wang, Taihong; Cai, Weibo

    2016-06-01

    Polyethylene glycol (PEG) surface modification is one of the most widely used approaches to improve the solubility of inorganic nanoparticles, prevent their aggregation and prolong their in vivo blood circulation half-life. Herein, we developed double-PEGylated biocompatible reduced graphene oxide nanosheets anchored with iron oxide nanoparticles (RGO-IONP-1stPEG-2ndPEG). The nanoconjugates exhibited a prolonged blood circulation half-life (~27.7 h) and remarkable tumor accumulation (>11 %ID g-1) via an enhanced permeability and retention (EPR) effect. Due to the strong near-infrared absorbance and superparamagnetism of RGO-IONP-1stPEG-2ndPEG, multimodality imaging combining positron emission tomography (PET) imaging with magnetic resonance imaging (MRI) and photoacoustic (PA) imaging was successfully achieved. The promising results suggest the great potential of these nanoconjugates for multi-dimensional and more accurate tumor diagnosis and therapy in the future.

  15. Long circulating reduced graphene oxide-iron oxide nanoparticles for efficient tumor targeting and multimodality imaging.

    PubMed

    Xu, Cheng; Shi, Sixiang; Feng, Liangzhu; Chen, Feng; Graves, Stephen A; Ehlerding, Emily B; Goel, Shreya; Sun, Haiyan; England, Christopher G; Nickles, Robert J; Liu, Zhuang; Wang, Taihong; Cai, Weibo

    2016-07-01

    Polyethylene glycol (PEG) surface modification is one of the most widely used approaches to improve the solubility of inorganic nanoparticles, prevent their aggregation and prolong their in vivo blood circulation half-life. Herein, we developed double-PEGylated biocompatible reduced graphene oxide nanosheets anchored with iron oxide nanoparticles (RGO-IONP-(1st)PEG-(2nd)PEG). The nanoconjugates exhibited a prolonged blood circulation half-life (∼27.7 h) and remarkable tumor accumulation (>11 %ID g(-1)) via an enhanced permeability and retention (EPR) effect. Due to the strong near-infrared absorbance and superparamagnetism of RGO-IONP-(1st)PEG-(2nd)PEG, multimodality imaging combining positron emission tomography (PET) imaging with magnetic resonance imaging (MRI) and photoacoustic (PA) imaging was successfully achieved. The promising results suggest the great potential of these nanoconjugates for multi-dimensional and more accurate tumor diagnosis and therapy in the future. PMID:27109431

  16. Effects of soy hull pectin and insoluble fiber on physicochemical and oxidative characteristics of fresh and frozen/thawed beef patties.

    PubMed

    Kim, Hyun-Wook; Miller, Danika K; Lee, Yong Jae; Kim, Yuan H Brad

    2016-07-01

    The objective of this study was to determine the effects of pectin and insoluble fiber isolated from soy hulls on water-holding capacity (WHC), texture, color, and lipid oxidation of fresh and frozen/thawed beef patties. Beef patties were formulated with no dietary fiber (control), 1% soy hull pectin, insoluble fiber, or their mixture (1:1), respectively. The addition of soy hull pectin significantly decreased display weight loss and increased cook yield of both fresh and frozen/thawed beef patties. In addition, no significant difference in hardness between fresh and frozen/thawed beef patties was observed for all dietary fiber treatments. However, incorporation of insoluble soy hull fiber decreased color and lipid oxidation stabilities of both fresh and frozen/thawed beef patties. Our results indicate that the incorporation of soy hull pectin could be an effective non-meat ingredient to minimize water loss and hardness defects of frozen beef patties. PMID:26946478

  17. A process of applying polypyrrole-engineered pulp fibers prepared using hydrogen peroxide as oxidant to detoxification of Cr(VI)-contaminated water.

    PubMed

    Lei, Yu; Qian, Xueren; Shen, Jing; An, Xianhui

    2013-03-01

    In this study, different from previous reports, an alternative process for detoxification of Cr(VI)-contaminated water with polypyrrole-engineered pulp fibers prepared using low cost hydrogen peroxide as oxidant was proposed. The process conditions in preparation of the engineered fibers as well as the water treatment conditions were optimized, and the behavior of Cr desorption from the engineered fibers was evaluated. The results showed that the proposed process was highly efficient in Cr(VI)-detoxification via the integration of adsorption with reduction. Compared with the previously reported polyaniline-engineered fibers prepared with hydrogen peroxide as oxidant, the engineered fibers studied in this work was much more effective. PMID:23340110

  18. Carbon-fiber technology

    NASA Technical Reports Server (NTRS)

    Hansen, C. F.; Parker, J. A.

    1980-01-01

    The state of the art of PAN based carbon fiber manufacture and the science of fiber behavior is surveyed. A review is given of the stabilization by oxidation and the subsequent carbonization of fibers, of the apparent structure of fibers deduced from scanning electron microscopy, from X-ray scattering, and from similarities with soft carbons, and of the known relations between fiber properties and heat treatment temperature. A simplified model is invoked to explain the electrical properties of fibers and recent quantum chemical calculations on atomic clusters are used to elucidate some aspects of fiber conductivity. Some effects of intercalation and oxidative modification of finished fibers are summarized.

  19. Characterization of Niobium Oxide Films Deposited by High Target Utilization Sputter Sources

    SciTech Connect

    Chow, R; Ellis, A D; Loomis, G E; Rana, S I

    2007-01-29

    High quality, refractory metal, oxide coatings are required in a variety of applications such as laser optics, micro-electronic insulating layers, nano-device structures, electro-optic multilayers, sensors and corrosion barriers. A common oxide deposition technique is reactive sputtering because the kinetic mechanism vaporizes almost any solid material in vacuum. Also, the sputtered molecules have higher energies than those generated from thermal evaporation, and so the condensates are smoother and denser than those from thermally-evaporated films. In the typical sputtering system, target erosion is a factor that drives machine availability. In some situations such as nano-layered capacitors, where the device's performance characteristics depends on thick layers, target life becomes a limiting factor on the maximizing device functionality. The keen interest to increase target utilization in sputtering has been addressed in a variety of ways such as target geometry, rotating magnets, and/or shaped magnet arrays. Also, a recent sputtering system has been developed that generates a high density plasma, directs the plasma beam towards the target in a uniform fashion, and erodes the target in a uniform fashion. The purpose of this paper is to characterize and compare niobia films deposited by two types of high target utilization sputtering sources, a rotating magnetron and a high density plasma source. The oxide of interest in this study is niobia because of its high refractive index. The quality of the niobia films were characterized spectroscopically in optical transmission, ellipsometrically, and chemical stoichiometry with X-ray photo-electron spectroscopy. The refractive index, extinction coefficients, Cauchy constants were derived from the ellipsometric modeling. The mechanical properties of coating density and stress are also determined.

  20. Oxidation-specific epitopes as targets for biotheranostic applications in humans: Biomarkers, molecular imaging and therapeutics

    PubMed Central

    Miller, Yury I.; Tsimikas, Sotirios

    2014-01-01

    Purpose of Review Emerging data demonstrates the potential of translational applications of antibodies directed against oxidation-specific epitopes (OSE). “Biotheranostics” in cardiovascular disease (CVD) describes targeting of OSE for biomarker, therapeutic and molecular imaging diagnostic applications. Recent findings Lipid oxidation collectively yields a large variety of oxidation-specific epitopes (OSE), such as oxidized phospholipids (OxPL) and malondialdehyde (MDA) epitopes. OSE are immunogenic, pro-inflammatory, pro-atherogenic and plaque destabilizing and represent danger associated molecular patterns (DAMPs). DAMPs are recognized by the innate immune system via pattern recognition receptors, including scavenger receptors IgM natural antibodies and complement factor H (CFH), that bind, neutralize and/or facilitate their clearance. Biomarker assays measuring OxPL present on apolipoprotein B-100 lipoproteins, and particularly on lipoprotein (a), predict the development of CVD events. In contrast, OxPL on plasminogen facilitate fibrinolysis and may reduce atherothrombosis. Oxidation-specific antibodies (OSA) attached to magnetic nanoparticles image lipid-rich, oxidation-rich plaques. Infusion or overexpression of OSA reduces the progression of atherosclerosis, suggesting that they may be used in similar applications in humans. Summary Using the accelerating knowledge base and improved understanding of the interplay of oxidation, inflammation and innate and adaptive immunity in atherogenesis, emerging clinical applications of OSA may identify, monitor and treat CVD in humans. PMID:23995232

  1. Chitin-glucan fiber effects on oxidized low-density lipoprotein: a randomized controlled trial

    PubMed Central

    Bays, H E; Evans, J L; Maki, K C; Evans, M; Maquet, V; Cooper, R; Anderson, J W

    2013-01-01

    Background/objectives: Elevated oxidized low-density lipoprotein (OxLDL) may promote inflammation, and is associated with increased risk of atherosclerotic coronary heart disease and worsening complications of diabetes mellitus. The primary objective of this study was to evaluate the efficacy of chitin-glucan (CG), alone and in combination with a potentially anti-inflammatory olive oil (OO) extract, for reducing OxLDL in subjects with borderline to high LDL cholesterol (LDL-C) levels. Subjects/methods: This 6-week, randomized, double-blind, placebo-controlled study of a novel, insoluble fiber derived from the Aspergillus niger mycelium, CG, evaluated 130 subjects free of diabetes mellitus with fasting LDL-C 3.37–4.92 mmol/l and glucose ⩽6.94 mmol/l. Participants were randomly assigned to receive CG (4.5 g/day; n=33), CG (1.5 g/day; n=32), CG (1.5 g/day) plus OO extract (135 mg/day; n=30), or matching placebo (n=35). Results: Administration of 4.5 g/day CG for 6 weeks significantly reduced OxLDL compared with placebo (P=0.035). At the end of study, CG was associated with lower LDL-C levels relative to placebo, although this difference was statistically significant only for the CG 1.5 g/day group (P=0.019). CG did not significantly affect high-density lipoprotein cholesterol, triglycerides, glucose, insulin or F2-isoprostane levels. Adverse events did not substantively differ between treatments and placebo. Conclusions: In this 6-week study, CG (4.5 g/day) reduced OxLDL, an effect that might affect the risk for atherosclerosis. PMID:22948945

  2. Preparation of silica-sustained electrospun polyvinylpyrrolidone fibers with uniform mesopores via oxidative removal of template molecules by H{sub 2}O{sub 2} treatment

    SciTech Connect

    Kang, Haigang; Zhu, Yihua; Shen, Jianhua; Yang, Xiaoling; Chen, Cheng; Cao, Huimin; Li, Chungzhong

    2010-07-15

    Silica-sustained electrospun PVP fibers with uniform mesopores were synthesized via facile oxidative removal of template molecules by H{sub 2}O{sub 2} extraction. Tetraethyl orthosilicate, polyvinylpyrrolidone (PVP), and triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer pluronic P{sub 123} compose the electrospinning sol to fabricate the silica-sustained PVP hybrid fibers. The effect of different post-treatment methods on the pore size distribution was investigated by calcination and extraction, respectively. Experimental results showed that oxidative removal of structure-directing agent P{sub 123} in the hybrid fibers by H{sub 2}O{sub 2} treatment can easily form narrow pore size distribution, and the incorporation of 3D silica skeleton built by hot steam aging facilitated preserving the original cylindrical morphology of fibers. Scanning electron microscopy (SEM), N{sub 2} adsorption-desorption isotherm, transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectra and thermogravimetric analysis (TGA) were used to characterize the hybrid fibers. The hybrid fibers can be expected to have potential applications in drug release or tissue engineering because of their suitable pore size, large surface area and good biocompatibility.

  3. Novel method for fabrication of metal- or oxide-nanoparticle doped silica-based specialty optical fibers

    NASA Astrophysics Data System (ADS)

    Lenardič, Borut; Kveder, Miha; Lisjak, Darja; Guillon, Herve; Bonnafous, Samuel

    2011-03-01

    Nanoparticle-doped optical fibers are causing significant scientific interest in different application fields. Nanoparticle-doping of silica glass layers during optical fiber preform fabrication was so far reported by sol-gel and solution doping processes, by flame hydrolysis spraying and by pulling hollow cylinders from nanoparticle suspensions. A new method for fabrication of high quality nanoparticle-doped fibers is suggested. Proposed method is based on "flash vaporization" deposition process, previously reported as method to fabricate rare earth- and metal ion-doped specialty optical fibers. Experiments were made where SiO2 layers were deposited using "flash vaporization"-equipped MCVD system, adding vapors carrying metal or oxide nanoparticles into deposition zone. Analysis of produced preforms confirms presence of nanoparticles in deposited layers, albeit with low deposition rate due to weak thermophoretic forces acting on very small particles or agglomerations. Based on results, a number of improvements were suggested and implemented in fabrication process, device design and choice of precursor materials. "Flash vaporization" method was demonstrated as suitable method for deposition of nanoparticles in silica layers, permitting in-situ fabrication of complete preforms, providing easy upgrade path for existing MCVD and OVD deposition systems and allowing simultaneous co-doping by a wide range of other co-dopants.

  4. Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

    NASA Astrophysics Data System (ADS)

    Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

    2015-07-01

    In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO.

  5. Targeting the Ataxia Telangiectasia Mutated-null phenotype in chronic lymphocytic leukemia with pro-oxidants

    PubMed Central

    Agathanggelou, Angelo; Weston, Victoria J.; Perry, Tracey; Davies, Nicholas J.; Skowronska, Anna; Payne, Daniel T.; Fossey, John S.; Oldreive, Ceri E.; Wei, Wenbin; Pratt, Guy; Parry, Helen; Oscier, David; Coles, Steve J.; Hole, Paul S.; Darley, Richard L.; McMahon, Michael; Hayes, John D.; Moss, Paul; Stewart, Grant S.; Taylor, A. Malcolm R.; Stankovic, Tatjana

    2015-01-01

    Inactivation of the Ataxia Telangiectasia Mutated gene in chronic lymphocytic leukemia results in resistance to p53-dependent apoptosis and inferior responses to treatment with DNA damaging agents. Hence, p53-independent strategies are required to target Ataxia Telangiectasia Mutated-deficient chronic lymphocytic leukemia. As Ataxia Telangiectasia Mutated has been implicated in redox homeostasis, we investigated the effect of the Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia genotype on cellular responses to oxidative stress with a view to therapeutic targeting. We found that in comparison to Ataxia Telangiectasia Mutated-wild type chronic lymphocytic leukemia, pro-oxidant treatment of Ataxia Telangiectasia Mutated-null cells led to reduced binding of NF-E2 p45-related factor-2 to antioxidant response elements and thus decreased expression of target genes. Furthermore, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia cells contained lower levels of antioxidants and elevated mitochondrial reactive oxygen species. Consequently, Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia, but not tumors with 11q deletion or TP53 mutations, exhibited differentially increased sensitivity to pro-oxidants both in vitro and in vivo. We found that cell death was mediated by a p53- and caspase-independent mechanism associated with apoptosis inducing factor activity. Together, these data suggest that defective redox-homeostasis represents an attractive therapeutic target for Ataxia Telangiectasia Mutated-null chronic lymphocytic leukemia. PMID:25840602

  6. Effect of Cattle Breed on Meat Quality, Muscle Fiber Characteristics, Lipid Oxidation and Fatty Acids in China

    PubMed Central

    Xie, Xiangxue; Meng, Qingxiang; Cui, Zhenliang; Ren, Liping

    2012-01-01

    The objective was to compare meat quality, muscle fiber characteristics, lipid oxidation and fatty acids of Limousin (LIM), Simmtental (SIM), Luxi (LX), Qinchuan (QC) and Jinnan (JN) offered the same diet in China. After finishing, eight bulls from each breed were randomly selected for slaughter at 18.5 months old. Longissimus dorsi (ld) muscle was taken from the carcass for meat quality evaluations. Breed had little effect on most of meat and fat color parameters except for Hue and b* in which QC had lower values. LIM showed higher pH (24 h) and better water holding capacity than other breeds. LIM showed the lowest dry matter content but the highest crude protein. LX and LIM had higher percentage and density of red muscle fiber than other breeds. Lipid oxidations were significantly lower in LIM than in QC, with the LX, SIM and JN having the intermediate values. Compared to other four breeds, QC provided the highest values of polyunsaturated fatty acids (PUFA), n-6 fatty acids and n-3 fatty acids. In conclusion, LIM scored better on most of meat quality characteristics; however, local breeds such as LX and QC also had better muscle fiber characteristics and better fatty acids composition. PMID:25049633

  7. Changes of nitric oxide synthase-containing nerve fibers and parameters for oxidative stress after unilateral cavernous nerve resection or manuplation in rat penis.

    PubMed

    Ozkara, Hamdi; Alan, Cabir; Atukeren, Pinar; Uyaner, Ilhan; Demirci, Cihan; Gümüştaş, M Koray; Alici, Bulent

    2006-06-30

    After pelvic surgeries such as radical prostatectomy, two major complications--urinary incontinence and erectile dysfunction (ED) may occur. Etiologies for ED are multiple pathologic mediators/systems. Oxidative stress, which is known to be induced after surgical trauma, could be a cause of ED. The purposes of in this study are to investigate the effect of unilateral manipulation/ dissection and resection of the cavernous nerve (neurotomy) to NOS (nitric oxide synthase)-containing nerve fibers and pressure after electro stimulation in rat corpus cavernosum, and to determine whether these procedures would produce oxidative stress within rat cavernous tissue 3 weeks and 6 months after the operation. Male rats were divided into 5 groups. Rats in groups 1 and 2 underwent unilateral cavernous nerve manipulation and sacrificed 3 weeks and 6 months after the operation, respectively. Rats in groups 3 and 4 underwent unilateral neurotomy of a 5-mm. segment of the cavernous nerve, and they were sacrificed 3 weeks and 6 months after nerve ablation, respectively. Group 5 rats were control animals for biochemical analysis. Intracavernous pressure following electro stimulation reduced is significantly 3 weeks after unilateral resection, as compared to that of the manipulated nerve (P < 0.05), and it recovered 6 months after neurotomy. The recovery was also confirmed by NADPH (nicotinamide adenine dinucleotide phosphate) diaphorase staining in neurotomy groups. Lipid peroxidation, which is an indicater of oxidative stress, was determined by measuring thiobarbituric acid reacting substance (TBARS) levels and superoxide dismutase (SOD) activity. These markers indicated that unilateral cavernous nerve manipulation or resection produced oxidative stress within rat corpus cavernosum. Oxidative stress was more prominent 3 weeks after unilateral neurotomy (P < 0.05). Also, compared to the control animal group, oxidative stress was observed three weeks after manipulation of unilateral

  8. The intellectual disability gene Kirrel3 regulates target-specific mossy fiber synapse development in the hippocampus

    PubMed Central

    Martin, E Anne; Muralidhar, Shruti; Wang, Zhirong; Cervantes, Diégo Cordero; Basu, Raunak; Taylor, Matthew R; Hunter, Jennifer; Cutforth, Tyler; Wilke, Scott A; Ghosh, Anirvan; Williams, Megan E

    2015-01-01

    Synaptic target specificity, whereby neurons make distinct types of synapses with different target cells, is critical for brain function, yet the mechanisms driving it are poorly understood. In this study, we demonstrate Kirrel3 regulates target-specific synapse formation at hippocampal mossy fiber (MF) synapses, which connect dentate granule (DG) neurons to both CA3 and GABAergic neurons. Here, we show Kirrel3 is required for formation of MF filopodia; the structures that give rise to DG-GABA synapses and that regulate feed-forward inhibition of CA3 neurons. Consequently, loss of Kirrel3 robustly increases CA3 neuron activity in developing mice. Alterations in the Kirrel3 gene are repeatedly associated with intellectual disabilities, but the role of Kirrel3 at synapses remained largely unknown. Our findings demonstrate that subtle synaptic changes during development impact circuit function and provide the first insight toward understanding the cellular basis of Kirrel3-dependent neurodevelopmental disorders. DOI: http://dx.doi.org/10.7554/eLife.09395.001 PMID:26575286

  9. The intellectual disability gene Kirrel3 regulates target-specific mossy fiber synapse development in the hippocampus

    PubMed Central

    Martin, E Anne; Muralidhar, Shruti; Wang, Zhirong; Cervantes, Diégo Cordero; Basu, Raunak; Taylor, Matthew R; Hunter, Jennifer; Cutforth, Tyler; Wilke, Scott A; Ghosh, Anirvan; Williams, Megan E

    2015-01-01

    Synaptic target specificity, whereby neurons make distinct types of synapses with different target cells, is critical for brain function, yet the mechanisms driving it are poorly understood. In this study, we demonstrate Kirrel3 regulates target-specific synapse formation at hippocampal mossy fiber (MF) synapses, which connect dentate granule (DG) neurons to both CA3 and GABAergic neurons. Here, we show Kirrel3 is required for formation of MF filopodia; the structures that give rise to DG-GABA synapses and that regulate feed-forward inhibition of CA3 neurons. Consequently, loss of Kirrel3 robustly increases CA3 neuron activity in developing mice. Alterations in the Kirrel3 gene are repeatedly associated with intellectual disabilities, but the role of Kirrel3 at synapses remained largely unknown. Our findings demonstrate that subtle synaptic changes during development impact circuit function and provide the first insight toward understanding the cellular basis of Kirrel3-dependent neurodevelopmental disorders. DOI: http://dx.doi.org/10.7554/eLife.09395.001

  10. CHIRON TOOLS: Integrated Target Submission, Scheduling and Observing Systems for a High-Resolution Fiber-Fed Spectrograph

    NASA Astrophysics Data System (ADS)

    Brewer, John M.; Giguere, Matthew; Fischer, Debra A.

    2014-01-01

    The CHIRON spectrometer is a new high-resolution, fiber-fed instrument on the 1.5 m telescope at Cerro Tololo Inter-America Observatory (CTIO). To optimize use of the instrument and limited human resources, we have designed an integrated set of Web applications allowing target submission, observing script planning, nightly script execution and logging, and access to reduced data by multiple users. The unified and easy-to-use interface has dramatically reduced the time needed to submit and schedule observations and improved the efficiency and accuracy of nightly operations. We present our experience to help astronomers and project managers who need to plan for the scope of effort required to commission a queue-scheduled facility instrument.

  11. Identifying initial molecular targets of PDT: protein and lipid oxidation products

    NASA Astrophysics Data System (ADS)

    Oleinick, Nancy L.; Kim, Junhwan; Rodriguez, Myriam E.; Xue, Liang-yan; Kenney, Malcolm E.; Anderson, Vernon E.

    2009-06-01

    Photodynamic Therapy (PDT) generates singlet oxygen (1O2) which oxidizes biomolecules in the immediate vicinity of its formation. The phthalocyanine photosensitizer Pc 4 localizes to mitochondria and endoplasmic reticulum, and the primary targets of Pc 4-PDT are expected to be lipids and proteins of those membranes. The initial damage then causes apoptosis in cancer cells via the release of cytochrome c (Cyt-c) from mitochondria into the cytosol, followed by the activation of caspases. That damage also triggers the induction of autophagy, an attempt by the cells to eliminate damaged organelles, or when damage is too extensive, to promote cell death. Cyt-c is bound to the cytosolic side of the mitochondrial inner membrane through association with cardiolipin (CL), a phospholipid containing four unsaturated fatty acids and thus easily oxidized by 1O2 or by other oxidizing agents. Increasing evidence suggests that oxidation of CL loosens its association with Cyt-c, and that the peroxidase activity of Cyt-c can oxidize CL. In earlier studies of Cyt-c in homogeneous medium by MALDI-TOF-MS and LC-ESI-MS, we showed that 1O2 generated by Pc 4-PDT oxidized histidine, methionine, tryptophan, and unexpectedly phenylalanine but not tyrosine. Most of the oxidation products were known to be formed by other oxidizing agents, such as hydroxyl radical, superoxide radical anion, and peroxynitrite. However, two products of histidine were unique to 1O2 and may be useful for reporting the action of 1O2 in cells and tissues. These products, as well as CL oxidation products, have now been identified in liposomes and mitochondria after Pc 4-PDT. In mitochondria, the PDT dose-dependent oxidations can be related to specific changes in mitochondrial function, Bcl-2 photodamage, and Cyt-c release. Thus, the role of PDT-generated 1O2 in oxidizing Cyt-c and CL and the interplay between protein and lipid targets may be highly relevant to understanding one mechanism for cell killing by PDT.

  12. Gold nanoparticle-conjugated anti-oxidized low-density lipoprotein antibodies for targeted lipidomics of oxidative stress biomarkers.

    PubMed

    Hinterwirth, Helmut; Stübiger, Gerald; Lindner, Wolfgang; Lämmerhofer, Michael

    2013-09-01

    Oxidized low-density lipoproteins (OxLDLs), in particular, oxidized phosphatidylcholines (OxPCs), are known to be involved in pathophysiological processes such as cardiovascular diseases and are described as potential biomarkers, for example, for atherosclerosis. In our study, we used the specific affinity of anti-OxLDL antibodies (Abs) conjugated to gold nanoparticles (GNPs) for extraction and enrichment of OxPCs via selective trapping of OxLDLs from plasma combined with the sensitive detection by liquid chromatography/tandem-mass spectrometry (LC-MS/MS). Successful bioconjugation chemistry of Abs via a bifunctional polyethylene glycol (PEG) spacer and protein G linkage, respectively, was controlled by measuring the surface plasmon resonance (SPR) spectra, size, and zeta potentials. Furthermore, the amount of Ab immobilized onto GNP via the PEG linker was determined. With the optimized immobilization chemistry, the ability and potential of the GNP-based extraction procedure was used for the determination of the dissociation constant, K(d), of the OxLDL binding to the GNP-Ab conjugate. Moreover, apparent K(d)'s were determined for individual PCs and their oxidation products using the compound-specific selected reaction monitoring mode, which allows the characterization of the Ab affinity and, thus, assessment of the potential antigenicity of (Ox)PCs bound to OxLDLs. In summary, the application of GNP-based bioanalysis for selective targeting of OxLDLs and the fast and sensitive detection by LC-MS/MS offers new possibilities for targeted lipidomics in lipoproteins as well as for oxidative stress lipid biomarker screening. PMID:23895666

  13. Alumina fiber strength improvement

    NASA Technical Reports Server (NTRS)

    Pepper, R. T.; Nelson, D. C.

    1982-01-01

    The effective fiber strength of alumina fibers in an aluminum composite was increased to 173,000 psi. A high temperature heat treatment, combined with a glassy carbon surface coating, was used to prevent degradation and improve fiber tensile strength. Attempts to achieve chemical strengthening of the alumina fiber by chromium oxide and boron oxide coatings proved unsuccessful. A major problem encountered on the program was the low and inconsistent strength of the Dupont Fiber FP used for the investigation.

  14. Nitric oxide and reactive oxygen species: Clues to target oxidative damage repair defective breast cancers.

    PubMed

    Somasundaram, Veena; Nadhan, Revathy; K Hemalatha, Sreelatha; Kumar Sengodan, Satheesh; Srinivas, Priya

    2016-05-01

    The identification of various biomolecules in cancer progression and therapy has led to the exploration of the roles of two cardinal players, namely Nitric Oxide (NO) and Reactive Oxygen Species (ROS) in cancer. Both ROS and NO display bimodal fashions of functional activity in a concentration dependent manner, by inducing either pro- or anti- tumorigenic signals. Researchers have identified the potential capability of NO and ROS in therapies owing to their role in eliciting pro-apoptotic signals at higher concentrations and their ability to sensitize cancer cells to one another as well as to other therapeutics. We review the prospects of NO and ROS in cancer progression and therapy, and analyze the role of a combinatorial therapy wherein an NO donor (SNAP) is used to sensitize the oxidative damage repair defective, triple negative breast cancer cells (HCC 1937) to a potent ROS inducer. Preliminary findings support the potential to employ various combinatorial regimes for anti-cancer therapies with regard to exploiting the chemo-sensitization property of NO donors. PMID:27017408

  15. Periodontitis in Rats Induces Systemic Oxidative Stress That Is Controlled by Bone-Targeted Antiresorptives

    PubMed Central

    Oktay, Sehkar; Chukkapalli, Sasanka S.; Rivera-Kweh, Mercedes F.; Velsko, Irina M.; Holliday, L. Shannon; Kesavalu, Lakshmyya

    2015-01-01

    Background Periodontitis is a chronic, polymicrobial inflammatory disease that degrades connective tissue and alveolar bone and results in tooth loss. Oxidative stress has been linked to the onset of periodontal tissue breakdown and systemic inflammation, and the success of antiresorptive treatments will rely on how effectively they can ameliorate periodontal disease–induced oxidative stress during oral infection. Methods Rats were infected with polybacterial inoculum consisting of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, as an oral lavage every other week for 12 weeks. Daily subcutaneous injections of enoxacin, bisenoxacin, alendronate, or doxycycline were administered for 6 weeks after 6 weeks of polybacterial infection in rats. The serum levels of oxidative stress parameters and antioxidant enzymes, including glutathione peroxidase, superoxide dismutase, and catalase, were evaluated in each of the infected, treated, and sham-infected rats. Results Rats infected with the periodontal pathogens displayed a five-fold increase in the oxidative stress index compared with controls as a result of increased levels of serum oxidants and decreases in total antioxidant activity. The overall decrease in antioxidant activity occurred despite increases in three important antioxidant enzymes, suggesting an imbalance between antioxidant macromolecules/small molecules production and antioxidant enzyme levels. Surprisingly, the bone-targeted antiresorptives bis-enoxacin and alendronate inhibited increases in oxidative stress caused by periodontitis. Bis-enoxacin, which has both antiresorptive and antibiotic activities, was more effective than alendronate, which acts only as an antiresorptive. Conclusion To the best of the authors’ knowledge, this is the first study to demonstrate that the increased oxidative stress induced by periodontal infection in rats can be ameliorated by bone-targeted antiresorptives. PMID:25101489

  16. Curcumin targeting the thioredoxin system elevates oxidative stress in HeLa cells

    SciTech Connect

    Cai, Wenqing; Zhang, Baoxin; Duan, Dongzhu; Wu, Jincai; Fang, Jianguo

    2012-08-01

    The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH, is ubiquitous in all cells and involved in many redox-dependent signaling pathways. Curcumin, a naturally occurring pigment that gives a specific yellow color in curry food, is consumed in normal diet up to 100 mg per day. This molecule has also been used in traditional medicine for the treatment of a variety of diseases. Curcumin has numerous biological functions, and many of these functions are related to induction of oxidative stress. However, how curcumin elicits oxidative stress in cells is unclear. Our previous work has demonstrated the way by which curcumin interacts with recombinant TrxR1 and alters the antioxidant enzyme into a reactive oxygen species (ROS) generator in vitro. Herein we reported that curcumin can target the cytosolic/nuclear thioredoxin system to eventually elevate oxidative stress in HeLa cells. Curcumin-modified TrxR1 dose-dependently and quantitatively transfers electrons from NADPH to oxygen with the production of ROS. Also, curcumin can drastically down-regulate Trx1 protein level as well as its enzyme activity in HeLa cells, which in turn remarkably decreases intracellular free thiols, shifting the intracellular redox balance to a more oxidative state, and subsequently induces DNA oxidative damage. Furthermore, curcumin-pretreated HeLa cells are more sensitive to oxidative stress. Knockdown of TrxR1 sensitizes HeLa cells to curcumin cytotoxicity, highlighting the physiological significance of targeting TrxR1 by curcumin. Taken together, our data disclose a previously unrecognized prooxidant mechanism of curcumin in cells, and provide a deep insight in understanding how curcumin works in vivo. -- Highlights: ► Curcumin induces oxidative stress by targeting the thioredoxin system. ► Curcumin-modified TrxR quantitatively oxidizes NADPH to generate ROS. ► Knockdown of TrxR1 augments curcumin's cytotoxicity in HeLa cells. ► Curcumin

  17. Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress

    SciTech Connect

    Muhsain, Siti Nur Fadzilah; Lang, Matti A.; Abu-Bakar, A'edah

    2015-01-01

    The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200 mg pyrazole/kg/day for 3 days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection. - Highlights: • Pyrazole induces oxidative stress in the mouse liver. • Pyrazole-induced oxidative stress induces mitochondrial targeting of key bilirubin regulatory enzymes, HMOX1

  18. Zinc oxide nanoparticle-doped nanoporous solgel fiber as a humidity sensor with enhanced sensitivity and large linear dynamic range.

    PubMed

    Aneesh, R; Khijwania, Sunil K

    2013-08-01

    An all-optical humidity sensor based on direct and exhaustive guided-mode attenuation in an in-house developed zinc oxide (ZnO) nanoparticle-immobilized bare solgel fiber is reported. The main objective of the present work is to enhance the sensitivity considerably while realizing a throughout linear response over a wide dynamic range. The developed sensor is characterized and performance characteristics of the sensor are compared with an optical fiber humidity sensor employing an evanescent wave absorption scheme in a straight and uniform probe, with ZnO nanoparticles-immobilized solgel film as humidity sensing cladding. Sensor response is observed to be linear over a wide dynamic range of 5%-95% relative humidity (RH). The observed linear sensitivity is 0.0103/% RH, which is ~9 times higher than the sensor employing the evanescent wave absorption scheme. In addition, sensor response is observed to be very fast, highly reversible, and repeatable. PMID:23913070

  19. Arginase: The Emerging Therapeutic Target for Vascular Oxidative Stress and Inflammation

    PubMed Central

    Yang, Zhihong; Ming, Xiu-Fen

    2013-01-01

    Oxidative stress and inflammation in the vascular wall are essential mechanisms of atherosclerosis and vascular dysfunctions associated with risk factors such as metabolic diseases, aging, hypertension, etc. Evidence has been provided that activation of the vascular endothelial cells in the presence of the risk factors promotes oxidative stress and vascular inflammatory responses, leading to acceleration of atherosclerotic vascular disease. Increasing number of studies from recent years demonstrates that uncoupling of endothelial nitric oxide synthase (eNOS), whereby the enzyme eNOS produces detrimental amount of superoxide anion O2− instead the vasoprotective nitric oxide (NO⋅), plays a critical role in vascular dysfunction under various pathophysiological conditions and in aging. The mechanisms of eNOS-uncoupling seem multiple and complex. Recent research provides emerging evidence supporting an essential role of increased activity of arginases including arginase-I and arginase-II in causing eNOS-uncoupling, which results in vascular oxidative stress and inflammatory responses, and ultimately leading to vascular diseases. This review article will summarize the most recent findings on the functional roles of arginases in vascular diseases and/or dysfunctions and the underlying mechanisms in relation to oxidative stress and inflammations. Moreover, regulatory mechanisms of arginases in the vasculature are reviewed and the future perspectives of targeting arginases as therapeutic options in vascular diseases are discussed. PMID:23781221

  20. Experimental and theoretical studies on localized surface plasmon resonance based fiber optic sensor using graphene oxide coated silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Nayak, Jeeban Kumar; Parhi, Purnendu; Jha, Rajan

    2016-07-01

    An optical fiber based refractive index sensor using graphene oxide (GO) encapsulated silver nanoparticles (AgNPs) is reported. The AgNPs are encapsulated with a very thin layer of GO as it controls the inter-particle distance thereby preventing aggregation. The encapsulation also enhances the colloidal stability and prevents the oxidation of the AgNPs by separating them from direct contact with the aqueous medium. High-resolution transmission electron microscopy results support the formation of 1 nm thick GO around AgNPs of an average size of 35 nm. A Raman spectrometer and a UV–VIS spectrometer have been used to characterize and study the synthesized nanoparticles along with GO. Further, Raman spectra support a 64.72% increase in D-peak intensity and a 52.91% increase in G-peak intensity of the GO-encapsulated AgNPs (GOE-AgNPs) with respect to GO. Further, the GOE-AgNPs are immobilized on the core of functionalized plastic-cladded silica fiber. FESEM confirms the immobilization of the GOE-AgNPs on the fiber core. We observed that the peak absorbance changes by 87.55% with a 0.05 change in the refractive index. The sensitivity of the proposed fiber sensor is found to be 0.9406 ΔA/RIU along with a resolution of 12.8  ×  {{10}-4} RIU. MATLAB is used to calculate the absorbance of the AgNPs by considering the bound and free electron contribution along with the size-dependent dispersion of the nanoparticles. We found that the simulation results are in good agreement with the experimental results.

  1. 1,4-Dihydropyridine Derivatives: Dihydronicotinamide Analogues—Model Compounds Targeting Oxidative Stress

    PubMed Central

    Velena, Astrida; Zarkovic, Neven; Gall Troselj, Koraljka; Bisenieks, Egils; Krauze, Aivars; Poikans, Janis; Duburs, Gunars

    2016-01-01

    Many 1,4-dihydropyridines (DHPs) possess redox properties. In this review DHPs are surveyed as protectors against oxidative stress (OS) and related disorders, considering the DHPs as specific group of potential antioxidants with bioprotective capacities. They have several peculiarities related to antioxidant activity (AOA). Several commercially available calcium antagonist, 1,4-DHP drugs, their metabolites, and calcium agonists were shown to express AOA. Synthesis, hydrogen donor properties, AOA, and methods and approaches used to reveal biological activities of various groups of 1,4-DHPs are presented. Examples of DHPs antioxidant activities and protective effects of DHPs against OS induced damage in low density lipoproteins (LDL), mitochondria, microsomes, isolated cells, and cell cultures are highlighted. Comparison of the AOA of different DHPs and other antioxidants is also given. According to the data presented, the DHPs might be considered as bellwether among synthetic compounds targeting OS and potential pharmacological model compounds targeting oxidative stress important for medicinal chemistry. PMID:26881016

  2. Daunomycin-loaded superparamagnetic iron oxide nanoparticles: Preparation, magnetic targeting, cell cytotoxicity, and protein delivery research.

    PubMed

    Liu, Min-Chao; Jin, Shu-Fang; Zheng, Min; Wang, Yan; Zhao, Peng-Liang; Tang, Ding-Tong; Chen, Jiong; Lin, Jia-Qi; Wang, Xia-Hong; Zhao, Ping

    2016-08-01

    The clinical use of daunomycin is restricted by dose-dependent toxicity and low specificity against cancer cells. In the present study, modified superparamagnetic iron oxide nanoparticles were employed to load daunomycin and the drug-loaded nanospheres exhibited satisfactory size and smart pH-responsive release. The cellular uptake efficiency, targeted cell accumulation, and cell cytotoxicity experimental results proved that the superparamagnetic iron oxide nanoparticle-loading process brings high drug targeting without decreasing the cytotoxicity of daunomycin. Moreover, a new concern for the evaluation of nanophase drug delivery's effects was considered, with monitoring the interactions between human serum albumin and the drug-loaded nanospheres. Results from the multispectroscopic techniques and molecular modeling calculation elucidate that the drug delivery has detectable deleterious effects on the frame conformation of protein, which may affect its physiological function. PMID:27288463

  3. 1,4-Dihydropyridine Derivatives: Dihydronicotinamide Analogues-Model Compounds Targeting Oxidative Stress.

    PubMed

    Velena, Astrida; Zarkovic, Neven; Gall Troselj, Koraljka; Bisenieks, Egils; Krauze, Aivars; Poikans, Janis; Duburs, Gunars

    2016-01-01

    Many 1,4-dihydropyridines (DHPs) possess redox properties. In this review DHPs are surveyed as protectors against oxidative stress (OS) and related disorders, considering the DHPs as specific group of potential antioxidants with bioprotective capacities. They have several peculiarities related to antioxidant activity (AOA). Several commercially available calcium antagonist, 1,4-DHP drugs, their metabolites, and calcium agonists were shown to express AOA. Synthesis, hydrogen donor properties, AOA, and methods and approaches used to reveal biological activities of various groups of 1,4-DHPs are presented. Examples of DHPs antioxidant activities and protective effects of DHPs against OS induced damage in low density lipoproteins (LDL), mitochondria, microsomes, isolated cells, and cell cultures are highlighted. Comparison of the AOA of different DHPs and other antioxidants is also given. According to the data presented, the DHPs might be considered as bellwether among synthetic compounds targeting OS and potential pharmacological model compounds targeting oxidative stress important for medicinal chemistry. PMID:26881016

  4. Unchanged content of oxidative enzymes in fast-twitch muscle fibers and kinetics after intensified training in trained cyclists

    PubMed Central

    Christensen, Peter M; Gunnarsson, Thomas P; Thomassen, Martin; Wilkerson, Daryl P; Nielsen, Jens Jung; Bangsbo, Jens

    2015-01-01

    The present study examined if high intensity training (HIT) could increase the expression of oxidative enzymes in fast-twitch muscle fibers causing a faster oxygen uptake () response during intense (INT), but not moderate (MOD), exercise and reduce the slow component and muscle metabolic perturbation during INT. Pulmonary kinetics was determined in eight trained male cyclists (-max: 59 ± 4 (means ± SD) mL min−1 kg−1) during MOD (205 ± 12 W ∼65% -max) and INT (286 ± 17 W ∼85% -max) exercise before and after a 7-week HIT period (30-sec sprints and 4-min intervals) with a 50% reduction in volume. Both before and after HIT the content in fast-twitch fibers of CS (P < 0.05) and COX-4 (P < 0.01) was lower, whereas PFK was higher (P < 0.001) than in slow-twitch fibers. Content of CS, COX-4, and PFK in homogenate and fast-twitch fibers was unchanged with HIT. Maximal activity (μmol g DW−1 min−1) of CS (56 ± 8 post-HIT vs. 59 ± 10 pre-HIT), HAD (27 ± 6 vs. 29 ± 3) and PFK (340 ± 69 vs. 318 ± 105) and the capillary to fiber ratio (2.30 ± 0.16 vs. 2.38 ± 0.20) was unaltered following HIT. kinetics was unchanged with HIT and the speed of the primary response did not differ between MOD and INT. Muscle creatine phosphate was lower (42 ± 15 vs. 66 ± 17 mmol kg DW−1) and muscle lactate was higher (40 ± 18 vs. 14 ± 5 mmol kg DW−1) at 6 min of INT (P < 0.05) after compared to before HIT. A period of intensified training with a volume reduction did not increase the content of oxidative enzymes in fast-twitch fibers, and did not change kinetics. PMID:26152692

  5. Pathogenesis of Target Organ Damage in Hypertension: Role of Mitochondrial Oxidative Stress

    PubMed Central

    Rubattu, Speranza; Pagliaro, Beniamino; Pierelli, Giorgia; Santolamazza, Caterina; Di Castro, Sara; Mennuni, Silvia; Volpe, Massimo

    2014-01-01

    Hypertension causes target organ damage (TOD) that involves vasculature, heart, brain and kidneys. Complex biochemical, hormonal and hemodynamic mechanisms are involved in the pathogenesis of TOD. Common to all these processes is an increased bioavailability of reactive oxygen species (ROS). Both in vitro and in vivo studies explored the role of mitochondrial oxidative stress as a mechanism involved in the pathogenesis of TOD in hypertension, especially focusing on atherosclerosis, heart disease, renal failure, cerebrovascular disease. Both dysfunction of mitochondrial proteins, such as uncoupling protein-2 (UCP2), superoxide dismutase (SOD) 2, peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), calcium channels, and the interaction between mitochondria and other sources of ROS, such as NADPH oxidase, play an important role in the development of endothelial dysfunction, cardiac hypertrophy, renal and cerebral damage in hypertension. Commonly used anti-hypertensive drugs have shown protective effects against mitochondrial-dependent oxidative stress. Notably, few mitochondrial proteins can be considered therapeutic targets on their own. In fact, antioxidant therapies specifically targeted at mitochondria represent promising strategies to reduce mitochondrial dysfunction and related hypertensive TOD. In the present article, we discuss the role of mitochondrial oxidative stress as a contributing factor to hypertensive TOD development. We also provide an overview of mitochondria-based treatment strategies that may reveal useful to prevent TOD and reduce its progression. PMID:25561233

  6. Synthesis and Evaluation of Folate-Conjugated Phenanthraquinones for Tumor-Targeted Oxidative Chemotherapy

    PubMed Central

    Kumar, Ajay; Chelvam, Venkatesh; Sakkarapalayam, Mahalingam; Li, Guo; Sanchez-Cruz, Pedro; Piñero, Natasha S.; Low, Philip S.; Alegria, Antonio E.

    2016-01-01

    Almost all cells are easily killed by exposure to potent oxidants. Indeed, major pathogen defense mechanisms in both animal and plant kingdoms involve production of an oxidative burst, where host defense cells show an invading pathogen with reactive oxygen species (ROS). Although cancer cells can be similarly killed by ROS, development of oxidant-producing chemotherapies has been limited by their inherent nonspecificity and potential toxicity to healthy cells. In this paper, we describe the targeting of an ROS-generating molecule selectively to tumor cells using folate as the tumor-targeting ligand. For this purpose, we exploit the ability of 9,10-phenanthraquinone (PHQ) to enhance the continuous generation of H2O2 in the presence of ascorbic acid to establish a constitutive source of ROS within the tumor mass. We report here that incubation of folate receptor-expressing KB cells in culture with folate-PHQ plus ascorbate results in the death of the cancer cells with an IC50 of ~10 nM (folate-PHQ). We also demonstrate that a cleavable spacer linking folate to PHQ is significantly inferior to a noncleavable spacer, in contrast to most other folate-targeted therapeutic agents. Unfortunately, no evidence for folate-PHQ mediated tumor regression in murine tumor models is obtained, suggesting that unanticipated impediments to generation of cytotoxic quantities of ROS in vivo are encountered. Possible mechanisms and potential solutions to these unanticipated results are offered. PMID:27066312

  7. Continuous Fiber Ceramic Composites (CFCC)

    SciTech Connect

    R. A. Wagner

    2002-12-18

    This report summarizes work to develop CFCC's for various applications in the Industries of the Future (IOF) and power generation areas. Performance requirements range from relatively modest for hot gas filters to severe for turbine combustor liners and infrared burners. The McDermott Technology Inc. (MTI) CFCC program focused on oxide/oxide composite systems because they are known to be stable in the application environments of interest. The work is broadly focused on dense and porous composite systems depending on the specific application. Dense composites were targeted at corrosion resistant components, molten aluminum handling components and gas turbine combustor liners. The development work on dense composites led to significant advances in fiber coatings for oxide fibers and matrix densification. Additionally, a one-step fabrication process was developed to produce low cost composite components. The program also supported key developments in advanced oxide fibers that resulted in an improved version of Nextel 610 fiber (commercially available as Nextel 650) and significant progress in the development of a YAG/alumina fiber. Porous composite development focused on the vacuum winding process used to produce hot gas filters and infrared burner components.

  8. Fiber optic hydrogen gas sensor utilizing surface plasmon resonance and native defects of zinc oxide by palladium

    NASA Astrophysics Data System (ADS)

    Tabassum, Rana; Gupta, Banshi D.

    2016-01-01

    We present an experimental study on a surface plasmon resonance (SPR) based fiber optic hydrogen gas sensor employing a palladium doped zinc oxide nanocomposite (ZnO(1-x)Pd x , 0 ≤ x ≤ 0.85) layer over the silver coated unclad core of the fiber. Palladium doped zinc oxide nanocomposites (ZnO(1-x)Pd x ) are prepared by a chemical route for different composition ratios and their structural, morphological and hydrogen sensing properties are investigated experimentally. The sensing principle involves the absorption of hydrogen gas by ZnO(1-x)Pd x , altering its dielectric function. The change in the dielectric constant is analyzed in terms of the red shift of the resonance wavelength in the visible region of the electromagnetic spectrum. To check the sensing capability of sensing probes fabricated with varying composition ratio (x) of nanocomposite, the SPR curves are recorded typically for 0% H2 and 4% H2 in N2 atmosphere for each fabricated probe. On changing the concentration of hydrogen gas from 0% to 4%, the red shift in the SPR spectrum confirms the change in dielectric constant of ZnO(1-x)Pd x on exposure to hydrogen gas. It is noted that the shift in the SPR spectrum increases monotonically up to a certain fraction of Pd in zinc oxide, beyond which it starts decreasing. SEM images and the photoluminescence (PL) spectra reveal that Pd dopant atoms substitutionally incorporated into the ZnO lattice profoundly affect its defect levels; this is responsible for the optimal composition of ZnO(1-x)Pd x to sense the hydrogen gas. The sensor is highly selective to hydrogen gas and possesses high sensitivity. Since optical fiber sensing technology is employed along with the SPR technique, the present sensor is capable of remote sensing and online monitoring of hydrogen gas.

  9. Curcumin targeting the thioredoxin system elevates oxidative stress in HeLa cells.

    PubMed

    Cai, Wenqing; Zhang, Baoxin; Duan, Dongzhu; Wu, Jincai; Fang, Jianguo

    2012-08-01

    The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH, is ubiquitous in all cells and involved in many redox-dependent signaling pathways. Curcumin, a naturally occurring pigment that gives a specific yellow color in curry food, is consumed in normal diet up to 100mg per day. This molecule has also been used in traditional medicine for the treatment of a variety of diseases. Curcumin has numerous biological functions, and many of these functions are related to induction of oxidative stress. However, how curcumin elicits oxidative stress in cells is unclear. Our previous work has demonstrated the way by which curcumin interacts with recombinant TrxR1 and alters the antioxidant enzyme into a reactive oxygen species (ROS) generator in vitro. Herein we reported that curcumin can target the cytosolic/nuclear thioredoxin system to eventually elevate oxidative stress in HeLa cells. Curcumin-modified TrxR1 dose-dependently and quantitatively transfers electrons from NADPH to oxygen with the production of ROS. Also, curcumin can drastically down-regulate Trx1 protein level as well as its enzyme activity in HeLa cells, which in turn remarkably decreases intracellular free thiols, shifting the intracellular redox balance to a more oxidative state, and subsequently induces DNA oxidative damage. Furthermore, curcumin-pretreated HeLa cells are more sensitive to oxidative stress. Knockdown of TrxR1 sensitizes HeLa cells to curcumin cytotoxicity, highlighting the physiological significance of targeting TrxR1 by curcumin. Taken together, our data disclose a previously unrecognized prooxidant mechanism of curcumin in cells, and provide a deep insight in understanding how curcumin works in vivo. PMID:22634334

  10. Zinc oxide nanowire interphase for enhanced interfacial strength in lightweight polymer fiber composites.

    PubMed

    Ehlert, Gregory J; Sodano, Henry A

    2009-08-01

    A novel functionalization method for aramid fibers is developed to enhance the bonding of a ZnO nanowire interphase grown on the fiber surface for interfacial strength enhancement. The nanowire interphase functionally grades the typically discrete interface and reduces the stress concentration between the fiber and matrix. The functionalization process is developed to improve the bonding between the ZnO nanowires and the aramid fiber and is validated through Fourier transform IR and X-ray photoelectron spectroscopy studies. Mechanical testing shows significant improvement in the interfacial shear strength with no decrease in the base fiber strength. This is the only technique found in the literature for the growth of a nanowire interphase on polymer fibers for structural enhancement without degrading the in-plane properties of the bulk composite. Furthermore, it is firmly shown that the functionalization process is a necessary condition for enhanced interfacial strength, demonstrating that ZnO nanowires strongly interact with carboxylic acid functional groups. PMID:20355800

  11. ICAM-1 targeted catalase encapsulated PLGA-b-PEG nanoparticles against vascular oxidative stress.

    PubMed

    Sari, Ece; Tunc-Sarisozen, Yeliz; Mutlu, Hulya; Shahbazi, Reza; Ucar, Gulberk; Ulubayram, Kezban

    2015-01-01

    Targeted delivery of therapeutics is the favourable idea, whereas it is possible to distribute the therapeutically active drug molecule only to the site of action. For this purpose, in this study, catalase encapsulated poly(D,L-lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-b-PEG) nanoparticles were developed and an endothelial target molecule (anti-ICAM-1) was conjugated to this carrier system in order to decrease the oxidative stress level in the target site. According to the enzymatic activity results, initial catalase activity of nanoparticles was increased from 27.39 U/mg to up to 45.66 U/mg by adding 5 mg/mL bovine serum albumin (BSA). After 4 h, initial catalase activity was preserved up to 46.98% while free catalase retained less than 4% of its activity in proteolytic environment. Furthermore, FITC labelled anti-ICAM-1 targeted catalase encapsulated nanoparticles (anti-ICAM-1/CatNPs) were rapidly taken up by cultured endothelial cells and concomitantly endothelial cells were resistant to H2O2 induced oxidative impairment. PMID:26471402

  12. Global lipidomics identifies cardiolipin oxidation as a mitochondrial target for redox therapy of acute brain injury

    PubMed Central

    Ji, Jing; Kline, Anthony E; Amoscato, Andrew; Arias, Alejandro S; Sparvero, Louis J; Tyurin, Vladimir A; Tyurina, Yulia Y; Fink, Bruno; Manole, Mioara D; Puccio, Ava M; Okonkwo, David O; Cheng, Jeffrey P; Alexander, Henry; Clark, Robert SB; Kochanek, Patrick M; Wipf, Peter; Kagan, Valerian E; Bayýr, Hülya

    2013-01-01

    Brain contains a highly diversified complement of molecular species of a mitochondria-specific phospholipid, cardiolipin (CL), which - due to its polyunsaturation - can readily undergo oxygenation. Here, we used global lipidomics analysis in experimental traumatic brain injury (TBI) and showed that TBI was accompanied by oxidative consumption of polyunsaturated CL and accumulation of more than 150 new oxygenated molecular species in CL. RNAi-based manipulations of CL-synthase and CL levels conferred resistance of primary rat cortical neurons to mechanical stretch - an in vitro model of traumatic neuronal injury. By applying the novel brain permeable mitochondria-targeted electron-scavenger, we prevented CL oxygenation in the brain, achieved a substantial reduction in neuronal death both in vitro and in vivo, and markedly reduced behavioral deficits and cortical lesion volume. We conclude that CL oxygenation generates neuronal death signals and that its prevention by mitochondria-targeted small molecule inhibitors represents a new target for neuro-drug discovery. PMID:22922784

  13. Endothelial targeting of nanocarriers loaded with antioxidant enzymes for protection against vascular oxidative stress and inflammation

    PubMed Central

    Hood, Elizabeth D.; Chorny, Michael; Greineder, Colin F.; Alferiev, Ivan; Levy, Robert J.; Muzykantov, Vladimir R.

    2015-01-01

    Endothelial-targeted delivery of antioxidant enzymes, catalase and superoxide dismutase (SOD), is promising strategy for protecting organs and tissues from inflammation and oxidative stress. Here we describe Protective Antioxidant Carriers for Endothelial Targeting (PACkET), the first carriers capable of targeted endothelial delivery of both catalase and SOD. PACkET formed through controlled precipitation loaded ~30% enzyme and protected it from proteolytic degradation, whereas attachment of PECAM monoclonal antibodies to surface of the enzyme-loaded carriers, achieved without adversely affecting their stability and functionality, provided targeting. Isotope tracing and microscopy showed that PACkET exhibited specific endothelial binding and internalization in vitro. Endothelial targeting of PACkET was validated in vivo by specific (vs IgG-control) accumulation in the pulmonary vasculature after intravenous injection achieving 33% of injected dose at 30 min. Catalase loaded PACkET protects endothelial cells from killing by H2O2 and alleviated the pulmonary edema and leukocyte infiltration in mouse model of endotoxin-induced lung injury, whereas SOD-loaded PACkET mitigated cytokine-induced endothelial pro-inflammatory activation and endotoxin-induced lung inflammation. These studies indicate that PACkET offers a modular approach for vascular targeting of therapeutic enzymes. PMID:24480537

  14. Oxidation-specific epitopes are dominant targets of innate natural antibodies in mice and humans.

    PubMed

    Chou, Meng-Yun; Fogelstrand, Linda; Hartvigsen, Karsten; Hansen, Lotte F; Woelkers, Douglas; Shaw, Peter X; Choi, Jeomil; Perkmann, Thomas; Bäckhed, Fredrik; Miller, Yury I; Hörkkö, Sohvi; Corr, Maripat; Witztum, Joseph L; Binder, Christoph J

    2009-05-01

    Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of oxidized lipoproteins and apoptotic cells. Adaptive immune responses to various oxidation-specific epitopes play an important role in atherogenesis. However, accumulating evidence suggests that these epitopes are also recognized by innate receptors, such as scavenger receptors on macrophages, and plasma proteins, such as C-reactive protein (CRP). Here, we provide multiple lines of evidence that oxidation-specific epitopes constitute a dominant, previously unrecognized target of natural Abs (NAbs) in both mice and humans. Using reconstituted mice expressing solely IgM NAbs, we have shown that approximately 30% of all NAbs bound to model oxidation-specific epitopes, as well as to atherosclerotic lesions and apoptotic cells. Because oxidative processes are ubiquitous, we hypothesized that these epitopes exert selective pressure to expand NAbs, which in turn play an important role in mediating homeostatic functions consequent to inflammation and cell death, as demonstrated by their ability to facilitate apoptotic cell clearance. These findings provide novel insights into the functions of NAbs in mediating host homeostasis and into their roles in health and diseases, such as chronic inflammatory diseases and atherosclerosis. PMID:19363291

  15. ReaxFF Study of the Oxidation of Lignin Model Compounds for the Most Common Linkages in Softwood in View of Carbon Fiber Production

    SciTech Connect

    Beste, Ariana

    2014-01-01

    Lignin is an underused but major component of biomass. One possible area of utilization is the production of carbon fiber. A necessary processing step is the stabilization of lignin fiber (typically in an oxygen environment) before high temperature treatment. We investigate oxidative, thermal conversion of lignin using computational methods. Dilignol model compounds for the most common (seven) linkages in softwood are chosen to represent the diverse structure of lignin. We perform molecular dynamics simulation where the potential energy surface is described by a reactive force field (ReaxFF). We calculate overall activation energies for model conversion and reveal initial mechanisms of formaldehyde formation. We record fragmentation patterns and average carbon oxidation numbers at various temperatures. Most importantly, we identify mechanisms for stabilizing reactions that result in cyclic, and rigid connections in softwood lignin fibers that are necessary for further processing into carbon fibers.

  16. Matrix metalloproteinase gene expressions might be oxidative stress targets in gastric cancer cell lines

    PubMed Central

    Gencer, Salih; Cebeci, Anil

    2013-01-01

    Objective Oxidative stress is linked to increased risk of gastric cancer and matrix metalloproteinases (MMPs) are important in the invasion and metastasis of gastric cancer. We aimed to analyze the effect of the accumulation of oxidative stress in the gastric cancer MKN-45 and 23132/87 cells following hydrogen peroxide (H2O2) exposure on the expression patterns of MMP-1, MMP-3, MMP-7, MMP-9, MMP-10, MMP-11, MMP-12, MMP-14, MMP-15, MMP-17, MMP-23, MMP-28, and β-catenin genes. Methods The mRNA transcripts in the cells were determined by RT-PCR. Following H2O2 exposure, oxidative stress in the viable cells was analyzed by 2',7'-dichlorofluorescein diacetate (DCFH-DA). Caffeic acid phenethyl ester (CAPE) was used to eliminate oxidative stress and the consequence of H2O2 exposure and its removal on the expressions of the genes were evaluated by quantitative real-time PCR. Results The expressions of MMP-1, MMP-7, MMP-14, MMP-15, MMP-17 and β-catenin in MKN-45 cells and only the expression of MMP-15 in 23132/87 cells were increased. Removal of the oxidative stress resulted in decrease in the expressions of MMP genes of which the expressions were increased after H2O2 exposure. β-catenin, a transcription factor for many genes including MMPs, also displayed decreased levels of expression in both of the cell lines following CAPE treatment. Conclusions Our data suggest that there is a remarkable link between the accumulation of oxidative stress and the increased expressions of MMP genes in the gastric cancer cells and MMPs should be considered as potential targets of therapy in gastric cancers due to its continuous exposure to oxidative stress. PMID:23825909

  17. Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress.

    PubMed

    Muhsain, Siti Nur Fadzilah; Lang, Matti A; Abu-Bakar, A'edah

    2015-01-01

    The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200mgpyrazole/kg/day for 3days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection. PMID:25478736

  18. Boron nitride converted carbon fiber

    DOEpatents

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  19. Stable narrow spacing dual-wavelength Q-switched graphene oxide embedded in a photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Soltanian, M. R. K.; Alimadad, M.; Harun, S. W.

    2014-10-01

    An ultra-stable dual-wavelength saturable absorber based on a cladding-embedded commercial graphene oxide (GO) solution by capillary action in a solid core photonic crystal fiber (PCF) is demonstrated for the first time. The saturation absorption property is achieved through evanescent coupling between the guided light and the cladding-filled graphene layers. Stable spacing dual-wavelength fiber lasing is attained by controlling the polarization state of a simple 0.9 m long ring of highly doped Leikki Er80-8/125 erbium-doped fiber as the primary gain medium with PCF, polarization controller and tunable bandpass filter. Embedded GO is used to generate the desired pulsed output, and the laser is capable of generating pulses having a repetition rate of 24 kHz with an average output power and pulse energy of 0.167 mW and 8.98 nJ, respectively, at the maximum pump power of 220 mW.

  20. MiR-25 protects cardiomyocytes against oxidative damage by targeting the mitochondrial calcium uniporter.

    PubMed

    Pan, Lei; Huang, Bi-Jun; Ma, Xiu-E; Wang, Shi-Yi; Feng, Jing; Lv, Fei; Liu, Yuan; Liu, Yi; Li, Chang-Ming; Liang, Dan-Dan; Li, Jun; Xu, Liang; Chen, Yi-Han

    2015-01-01

    MicroRNAs (miRNAs) are a class of small non-coding RNAs, whose expression levels vary in different cell types and tissues. Emerging evidence indicates that tissue-specific and -enriched miRNAs are closely associated with cellular development and stress responses in their tissues. MiR-25 has been documented to be abundant in cardiomyocytes, but its function in the heart remains unknown. Here, we report that miR-25 can protect cardiomyocytes against oxidative damage by down-regulating mitochondrial calcium uniporter (MCU). MiR-25 was markedly elevated in response to oxidative stimulation in cardiomyocytes. Further overexpression of miR-25 protected cardiomyocytes against oxidative damage by inactivating the mitochondrial apoptosis pathway. MCU was identified as a potential target of miR-25 by bioinformatical analysis. MCU mRNA level was reversely correlated with miR-25 under the exposure of H2O2, and MCU protein level was largely decreased by miR-25 overexpression. The luciferase reporter assay confirmed that miR-25 bound directly to the 3' untranslated region (UTR) of MCU mRNA. MiR-25 significantly decreased H2O2-induced elevation of mitochondrial Ca2+ concentration, which is likely to be the result of decreased activity of MCU. We conclude that miR-25 targets MCU to protect cardiomyocytes against oxidative damages. This finding provides novel insights into the involvement of miRNAs in oxidative stress in cardiomyocytes. PMID:25764156

  1. Targeted Nitric Oxide Delivery by Supramolecular Nanofibers for the Prevention of Restenosis After Arterial Injury

    PubMed Central

    Bahnson, Edward S.M.; Kassam, Hussein A.; Moyer, Tyson J.; Jiang, Wulin; Morgan, Courtney E.; Vercammen, Janet M.; Jiang, Qun; Flynn, Megan E.; Stupp, Samuel I.

    2016-01-01

    Abstract Aims: Cardiovascular interventions continue to fail as a result of arterial restenosis secondary to neointimal hyperplasia. We sought to develop and evaluate a systemically delivered nanostructure targeted to the site of arterial injury to prevent neointimal hyperplasia. Nanostructures were based on self-assembling biodegradable molecules known as peptide amphiphiles. The targeting motif was a collagen-binding peptide, and the therapeutic moiety was added by S-nitrosylation of cysteine residues. Results: Structure of the nanofibers was characterized by transmission electron microscopy and small-angle X-ray scattering. S-nitrosylation was confirmed by mass spectrometry, and nitric oxide (NO) release was assessed electrochemically and by chemiluminescent detection. The balloon carotid artery injury model was performed on 10-week-old male Sprague-Dawley rats. Immediately after injury, nanofibers were administered systemically via tail vein injection. S-nitrosylated (S-nitrosyl [SNO])-targeted nanofibers significantly reduced neointimal hyperplasia 2 weeks and 7 months following balloon angioplasty, with no change in inflammation. Innovation: This is the first time that an S-nitrosothiol (RSNO)-based therapeutic was shown to have targeted local effects after systemic administration. This approach, combining supramolecular nanostructures with a therapeutic NO-based payload and a targeting moiety, overcomes the limitations of delivering NO to a site of interest, avoiding undesirable systemic side effects. Conclusion: We successfully synthesized and characterized an RSNO-based therapy that when administered systemically, targets directly to the site of vascular injury. By integrating therapeutic and targeting chemistries, these targeted SNO nanofibers provided durable inhibition of neointimal hyperplasia in vivo and show great potential as a platform to treat cardiovascular diseases. Antioxid. Redox Signal. 27, 401–418. PMID:26593400

  2. Oxidative metabolism involved in non-targeted effects induced by proton radiation in intact Arabidopsis seeds.

    PubMed

    Mei, Tao; Yang, Gen; Quan, Yi; Wang, Weikang; Zhang, Weiming; Xue, Jianming; Wu, Lijun; Gu, Hongya; Schettino, Giuseppe; Wang, Yugang

    2011-01-01

    Non-targeted effects induced by ionizing radiation have been demonstrated both in vitro and in vivo. Previously, we have also demonstrated the existence of non-targeted effects in intact Arabidopsis seeds following low-energy heavy-ion radiation. In the present study, 6.5 MeV protons with 8 × 10(11) ions/cm(2) and 2 × 10(11) ions/cm(2) fluence respectively were used to irradiate non-shielded or partial-shielded Arabidopsis seeds to further explore the mechanisms which regulate in vivo non-targeted effects and to investigate the difference between damage caused by non-targeted effects and direct irradiation. Results showed that excess reactive oxygen species (ROS) are present in the non-irradiated part of the partially irradiated samples, indicating that in vivo non-targeted effects can promote the generation of excess metabolic ROS in the non-irradiated shoot apical meristem/root apical meristem cells. Furthermore, pretreatment with 0.5% ROS scavenger dimethyl sulfoxide (DMSO) or 0.02 mM reactive nitrogen species (RNS) scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) significantly suppresses the non-targeted effects in the partially irradiated samples, while in the whole-body irradiated samples, the cPTIO pretreatment has no effect. On the other hand using antioxidant enzyme assays, superoxide dismutase activity was found to increase for partial irradiated samples and decrease for the whole-body exposed seeds. Taken together, these results implicate that damage caused by non-targeted effects is different from that induced by direct irradiation in vivo. Metabolic products such as ROS and RNS are involved in the in vivo non-targeted effects. PMID:21343677

  3. Small RNA sequencing and degradome analysis of developing fibers of short fiber mutants Ligon-lintles-1 (Li1) and -2 (Li2) revealed a role for miRNAs and their targets in cotton fiber elongation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The length of cotton fiber is an important agronomic trait that directly affects the quality of yarn and fabric. Understanding the molecular basis of fiber elongation would provide a means for improvement of fiber length. Ligon-lintless-1 (Li1) and -2 (Li2) are monogenic and dominant mutations that ...

  4. The Influence of Interfacial Roughness on Fiber Sliding in Oxide Composites with La-Monazite Interphases

    NASA Technical Reports Server (NTRS)

    Davis, J. B.; Hay, R. S.; Marshall, D. B.; Morgan, P. E. D.; Sayir, A.; Gray, Hugh R. (Technical Monitor); Farmer, Serene C. (Technical Monitor)

    2002-01-01

    Room temperature debonding and sliding of La-Monazite coated fibers is assessed using a composite with a polycrystalline alumina matrix and fibers of several different single crystal (mullite, sapphire) and directionally solidified eutectic (Al2O3/Y3Al5O12 and Al2O3/Y-ZrO2) compositions. These fibers provide a range of residual stresses and interfacial roughnesses. Sliding occurred over a debond crack at the fiber-coating interface when the sliding displacement and surface roughness were relatively small. At large sliding displacements with relatively rough interfaces, the monazite coatings were deformed extensively by fracture, dislocations and occasional twinning, whereas the fibers were undamaged. Dense, fine-grained (10 nm) microstructures suggestive of dynamic recrystallization were also observed in the coatings. Frictional heating during sliding is assessed. The possibility of low temperature recrystallization is discussed in the light of the known resistance of monazite to radiation damage. The ability of La-Monazite to undergo plastic deformation relatively easily at low temperatures may be enabling for its use as a composite interface.

  5. Lactoferrin conjugated iron oxide nanoparticles for targeting brain glioma cells in magnetic particle imaging

    NASA Astrophysics Data System (ADS)

    Tomitaka, Asahi; Arami, Hamed; Gandhi, Sonu; Krishnan, Kannan M.

    2015-10-01

    Magnetic Particle Imaging (MPI) is a new real-time imaging modality, which promises high tracer mass sensitivity and spatial resolution directly generated from iron oxide nanoparticles. In this study, monodisperse iron oxide nanoparticles with median core diameters ranging from 14 to 26 nm were synthesized and their surface was conjugated with lactoferrin to convert them into brain glioma targeting agents. The conjugation was confirmed with the increase of the hydrodynamic diameters, change of zeta potential, and Bradford assay. Magnetic particle spectrometry (MPS), performed to evaluate the MPI performance of these nanoparticles, showed no change in signal after lactoferrin conjugation to nanoparticles for all core diameters, suggesting that the MPI signal is dominated by Néel relaxation and thus independent of hydrodynamic size difference or presence of coating molecules before and after conjugations. For this range of core sizes (14-26 nm), both MPS signal intensity and spatial resolution improved with increasing core diameter of nanoparticles. The lactoferrin conjugated iron oxide nanoparticles (Lf-IONPs) showed specific cellular internalization into C6 cells with a 5-fold increase in MPS signal compared to IONPs without lactoferrin, both after 24 h incubation. These results suggest that Lf-IONPs can be used as tracers for targeted brain glioma imaging using MPI.

  6. Heavy-Ion Irradiation of Thulium(III) Oxide Targets Prepared by Polymer-Assisted Deposition

    SciTech Connect

    Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, Tashi; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

    2008-09-15

    Thulium(III) oxide (Tm{sub 2}O{sub 3}) targets prepared by the polymer-assisted deposition (PAD) method were irradiated by heavy-ion beams to test the method's feasibility for nuclear science applications. Targets were prepared on silicon nitride backings (thickness of 1000 nm, 344 {micro}g/cm{sup 2}) and were irradiated with an {sup 40}Ar beam at laboratory frame energy of {approx}210 MeV (50 particle nA). The root mean squared (RMS) roughness prior to irradiation is 1.1 nm for a {approx}250 nm ({approx}220 {micro}g/cm{sup 2}) Tm{sub 2}O{sub 3} target, and an RMS roughness of 2.0 nm after irradiation was measured by atomic force microscopy (AFM). Scanning electron microscopy of the irradiated target reveals no significant differences in surface homogeneity when compared to imaging prior to irradiation. Target flaking was not observed from monitoring Rutherford scattered particles as a function of time.

  7. PSMA targeted docetaxel-loaded superparamagnetic iron oxide nanoparticles for prostate cancer.

    PubMed

    Nagesh, Prashanth K B; Johnson, Nia R; Boya, Vijaya K N; Chowdhury, Pallabita; Othman, Shadi F; Khalilzad-Sharghi, Vahid; Hafeez, Bilal B; Ganju, Aditya; Khan, Sheema; Behrman, Stephen W; Zafar, Nadeem; Chauhan, Subhash C; Jaggi, Meena; Yallapu, Murali M

    2016-08-01

    Docetaxel (Dtxl) is currently the most common therapeutic option for prostate cancer (PC). However, adverse side effects and problems associated with chemo-resistance limit its therapeutic outcome in clinical settings. A targeted nanoparticle system to improve its delivery to and activity at the tumor site could be an attractive strategy for PC therapy. Therefore, the objective of this study was to develop and determine the anti-cancer efficacy of a novel docetaxel loaded, prostate specific membrane antigen (PSMA) targeted superparamagnetic iron oxide nanoparticle (SPION) (J591-SPION-Dtxl) formulation for PC therapy. Our results showed the SPION-Dtxl formulation exhibits an optimal particle size and zeta potential, which can efficiently be internalized in PC cells. SPION-Dtxl exhibited potent anti-cancer efficacy via induction of the expression of apoptosis associated proteins, downregulation of anti-apoptotic proteins, and inhibition of chemo-resistance associated protein in PC cell lines. J591-SPION-Dtxl exhibited a profound uptake in C4-2 (PSMA(+)) cells compared to PC-3 (PSMA(-)) cells. A similar targeting potential was observed in ex-vivo studies in C4-2 tumors but not in PC-3 tumors, suggesting its tumor specific targeting. Overall, this study suggests that a PSMA antibody functionalized SPION-Dtxl formulation can be highly useful for targeted PC therapy. PMID:27058278

  8. Refinement of adsorptive coatings for fluorescent riboflavin-receptor-targeted iron oxide nanoparticles.

    PubMed

    Tsvetkova, Yoanna; Beztsinna, Nataliia; Jayapaul, Jabadurai; Weiler, Marek; Arns, Susanne; Shi, Yang; Lammers, Twan; Kiessling, Fabian

    2016-01-01

    Flavin mononucleotide (FMN) is a riboflavin derivative that can be exploited to target the riboflavin transporters (RFTs) and the riboflavin carrier protein (RCP) in cells with high metabolic activity. In this study we present the synthesis of different FMN-coated ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) and their efficiency as targeting contrast agents. Since FMN alone cannot stabilize the nanoparticles, we used adenosine phosphates - AMP, ADP and ATP - as spacers to obtain colloidally stable nanoparticles. Nucleotides with di- and triphosphate groups were intended to increase the USPIO charge and thus improve zeta potential and stability. However, all nanoparticles formed negatively charged clusters with similar properties in terms of zeta potential (-28 ± 2 mV), relaxivity (228-259 mM(-1)  s(-1) at 3 T) and hydrodynamic radius (53-85 nm). Molecules with a higher number of phosphate groups, such as ADP and ATP, have a higher adsorption affinity towards iron oxide, which, instead of providing more charge, led to partial desorption and replacement of FMN. Hence, we obtained USPIOs carrying different amounts of targeting agent, which significantly influenced the nanoparticles' uptake. The nanoparticles' uptake by different cancer cells and HUVECs was evaluated photometrically and with MR relaxometry, showing that the cellular uptake of the USPIOs increases with the FMN amount on their surface. Thus, for USPIOs targeted with riboflavin derivatives the use of spacers with increasing numbers of phosphate groups does not improve either zeta potential or the particles' stability, but rather detaches the targeting moieties from their surface, leading to lower cellular uptake. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26265388

  9. Determination of reactive oxygen species generated in laccase catalyzed oxidation of wood fibers from Chinese fir (Cunninghamia lanceolata) by electron spin resonance spectrometry.

    PubMed

    Zhou, Guanwu; Li, Jianing; Chen, Yongsheng; Zhao, Baolu; Cao, Yongjian; Duan, Xinfang; Cao, Yuanlin

    2009-01-01

    The aim of the present study was to determine whether the radical reaction intermediates--reactive oxygen species (ROS) were formed during the laccase-catalyzed oxidation of wood fibers from Chinese fir (Cunninghamia lanceolata) and to quantify tentatively its production with electron spin resonance (ESR) spectrometry. To investigate the activation pathways triggered by laccase, ESR spin-trapping techniques using N-tert-butyl-alpha-phenylnitrone (PBN) as spin trap followed by ethyl acetate extraction were employed to identify and quantify the free radical intermediates. ROS such as the superoxide and hydroxyl radical was detected and quantified in the laccase catalyzed oxidation of wood fibers, suggesting that ROS is the main free radical intermediates for laccase reaction. Based on the findings of the presence of ROS and previous literature on the free radical reaction of laccase oxidation of wood fibers, a possible reaction mechanism involving ROS-mediated attack on the domains of lignin which is not directly accessible for the enzyme and solubilized low-molecular mass lignins which function as reactive compounds like adhesives and may cling back to the fiber surface, could accordingly describe laccase-catalyzed oxidation of Chinese fir wood fibers. PMID:18650080

  10. Redox reactions in mammalian spermatogenesis and the potential targets of reactive oxygen species under oxidative stress

    PubMed Central

    Fujii, Junichi; Imai, Hirotaka

    2014-01-01

    Reduction-oxidation (Redox) reactions are ubiquitous mechanisms for vital activities in all organisms, and they play pivotal roles in the regulation of spermatogenesis as well. Here we focus on 3 redox-involved processes that have drawn much recent attention: the regulation of signal transduction by reactive oxygen species (ROS) such as hydrogen peroxide, oxidative protein folding in the endoplasmic reticulum (ER), and sulfoxidation of protamines during sperm chromatin condensation. The first 2 of these processes are emerging topics in cell biology and are applicable to most living cells, which includes spermatogenic cells. The roles of ROS in signal transduction have been elucidated in the last 2 decades and have received broad attention, most notably from the viewpoint of the proper control of mitotic signals. Redox processes in the ER are important because this is the organelle where secretory and membrane proteins are synthesized and proceed toward their functional structure, so that malfunction of the ER affects not only the involved cells but also the accepting cells of the secreted proteins in multicellular organisms. Sulfoxidation is the third of these processes, and the sulfoxidation of chromatin is a unique process in sperm maturation. During recent sulfoxidase research, GPX4 has emerged as a promising enzyme that plays essential roles in the production of fertile sperm, but the involvement of other redox proteins is also becoming evident. Because the molecules involved in the redox reactions are prone to oxidation, they can be sensitive to oxidative damage, which makes them potential targets for antioxidant therapy. PMID:26413390

  11. Treatment-Resistant Major Depression: Rationale for NMDA Receptors as Targets and Nitrous Oxide as Therapy

    PubMed Central

    Zorumski, Charles F.; Nagele, Peter; Mennerick, Steven; Conway, Charles R.

    2015-01-01

    Major depressive disorder (MDD) remains a huge personal and societal encumbrance. Particularly burdensome is a virulent subtype of MDD, treatment resistant major depression (TMRD), which afflicts 15–30% of MDD patients. There has been recent interest in N-methyl-d-aspartate receptors (NMDARs) as targets for treatment of MDD and perhaps TMRD. To date, most pre-clinical and clinical studies have focused on ketamine, although psychotomimetic and other side effects may limit ketamine’s utility. These considerations prompted a recent promising pilot clinical trial of nitrous oxide, an NMDAR antagonist that acts through a mechanism distinct from that of ketamine, in patients with severe TRMD. In this paper, we review the clinical picture of TRMD as a subtype of MDD, the evolution of ketamine as a fast-acting antidepressant, and clinical and basic science studies supporting the possible use of nitrous oxide as a rapid antidepressant. PMID:26696909

  12. Targeting ABL1-mediated Oxidative Stress Adaptation in Fumarate Hydratase-Deficient Cancer

    PubMed Central

    Sourbier, Carole; Ricketts, Christopher J.; Matsumoto, Shingo; Crooks, Daniel R.; Liao, Pei-Jyun; Mannes, Philip Z.; Yang, Youfeng; Wei, Ming-Hui; Srivastava, Gaurav; Ghosh, Sanchari; Chen, Viola; Vocke, Cathy D.; Merino, Maria; Srinivasan, Ramaprasad; Krishna, Murali C.; Mitchell, James B.; Pendergast, Ann Marie; Rouault, Tracey A.; Neckers, Len; Linehan, W. Marston

    2014-01-01

    SUMMARY Patients with germline fumarate hydratase (FH) mutation are predisposed to develop aggressive kidney cancer with few treatment options and poor therapeutic outcomes. Activity of the proto-oncogene ABL1 is upregulated in FH-deficient kidney tumors and drives a metabolic and survival signaling network necessary to cope with impaired mitochondrial function and abnormal accumulation of intracellular fumarate. Excess fumarate indirectly stimulates ABL1 activity while restoration of wild-type FH abrogates both ABL1 activation and the cytotoxicity caused by ABL1 inhibition or knockdown. ABL1 upregulates aerobic glycolysis via the mTOR/HIF1α pathway and neutralizes fumarate-induced proteotoxic stress by promoting nuclear localization of the anti-oxidant response transcription factor NRF2. Our findings identify ABL1 as a pharmacologically tractable therapeutic target in glycolytically dependent, oxidatively stressed tumors. PMID:25490448

  13. The preparation and characterization of highly aligned poly(epsilon-caprolactone)/poly ethylene oxide/chitosan ultrafine fiber for the application to tissue scaffold.

    PubMed

    Nien, Yu-Hsun; Wang, Jia-Yi; Tsai, Yan-Sheng

    2013-07-01

    The purpose of this study was to fabricate poly(epsilon-caprolactone) (PCL)/poly ethylene oxid (PEO)/chitosan (CS) ultrafine fiber in both aligned and random structures using electrospinning technique and their process parameters were optimized. The aligned and random PCL/PEO/chitosan ultrafine fibers were also used as scaffold for tissue engineering and their cell affinity was investigated. In the first part, we inspected the effect of environment conditions, solution properties, process parameters on PCL/PEO/chitosan ultrafine fiber. In the second part, the apparatus of electrospinning to manufacture highly aligned PCL/PEO/chitosan ultrafine fiber was developed. The effects of process parameters such as flow rate, design of collector and rotation speed of collecting drum on the morphology of ultrafine fiber were discussed. In addition, the cross link of PCL/PEO/chitosan ultrafine fiber by cross-linking agent was examined, too. The physical properties, chemical properties, and cell affinities of the aligned PCL/PEO/chitosan ultrafine fiber with or without cross link were measured. The chemical analysis and tensile strength of the ultrafine fiber were characterized using Fourier Transfer Infared Spectrophotometer and Universal Tensile Machine, respectively. The results show that the aligned PCL/PEO/chitosan ultrafine fibrous mat had the capacity to induce cellular alignment and enhance cellular elongation. PMID:23901493

  14. Graphene oxide based sol-gel stainless steel fiber for the headspace solid-phase microextraction of organophosphate ester flame retardants in water samples.

    PubMed

    Jin, Tingting; Cheng, Jing; Cai, Cuicui; Cheng, Min; Wu, Shiju; Zhou, Hongbin

    2016-07-29

    In this paper, graphene oxide was coated onto a stainless steel wire through sol-gel technique and it was used as a solid phase microextraction (SPME) fiber. The prepared fiber was characterized by scanning electron microscopy (SEM), which displayed that the fiber had crinkled surface and porous structure The application of the fiber was evaluated through the headspace SPME of nine organophosphate ester flame retardants (OPFRs) with different characteristics in water samples followed by gas chromatography and nitrogen-phosphorous detector (GC/NPD). The major factors influencing the extraction efficiency, including the extraction and desorption conditions, were studied and optimized. Under the optimum conditions, the proposed method was evaluated, and applied to the analysis of organophosphate ester flame retardants in real environmental water samples. The results demonstrated the HS-SPME method based on GO sol-gel fiber had good linearity (R>0.9928), and limits of detection (1.4-135.6ngL(-1)), high repeatability (RSD<9.8%) and good recovery (76.4-112.4%). The GO based sol-gel fiber displayed bigger extraction capability than the commercial PDMS fiber and the pure sol-gel fiber for both polar and apolar organophosphate esters, especially for the OPFRs containing benzene rings. PMID:27371020

  15. Receptor-targeted iron oxide nanoparticles for molecular MR imaging of inflamed atherosclerotic plaques.

    PubMed

    Tu, Chuqiao; Ng, Thomas S C; Sohi, Hargun K; Palko, Heather A; House, Adrian; Jacobs, Russell E; Louie, Angelique Y

    2011-10-01

    In a number of literature reports iron oxide nanoparticles have been investigated for use in imaging atherosclerotic plaques and found to accumulate in plaques via uptake by macrophages, which are critical in the process of atheroma initiation, propagation, and rupture. However, the uptake of these agents is non-specific; thus the labeling efficiency for plaques in vivo is not ideal. We have developed targeted agents to improve the efficiency for labeling macrophage-laden plaques. These probes are based on iron oxide nanoparticles coated with dextran sulfate, a ligand of macrophage scavenger receptor type A (SR-A). We have sulfated dextran-coated iron oxide nanoparticles (DIO) with sulfur trioxide, thereby targeting our nanoparticle imaging agents to SR-A. The sulfated DIO (SDIO) remained mono-dispersed and had an average hydrodynamic diameter of 62 nm, an r(1) relaxivity of 18.1 mM(-1) s(-1), and an r(2) relaxivity of 95.8 mM(-1) s(-1) (37 °C, 1.4 T). Cell studies confirmed that these nanoparticles were nontoxic and specifically targeted to macrophages. In vivo MRI after intravenous injection of the contrast agent into an atherosclerotic mouse injury model showed substantial signal loss on the injured carotid at 4 and 24 h post-injection of SDIO. No discernable signal decrease was seen at the control carotid and only mild signal loss was observed for the injured carotid post-injection of non-sulfated DIO, indicating preferential uptake of the SDIO particles at the site of atherosclerotic plaque. These results indicate that SDIO can facilitate MRI detection and diagnosis of vulnerable plaques in atherosclerosis. PMID:21742374

  16. Targeted delivery and controlled release of doxorubicin into cancer cells using a multifunctional graphene oxide.

    PubMed

    Lv, Yao; Tao, Lei; Annie Bligh, S W; Yang, Huihui; Pan, Qixia; Zhu, Limin

    2016-02-01

    We have synthesized a new multifunctional graphene oxide as a drug carrier targeting to hepatocarcinoma cells. Surface modified graphene oxide with polyethyleneimine (PEI) sequentially derivatised with fluorescein isothiocyanate (FI) and polyethylene glycol (PEG)-linked lactobionic acid (LA), and acetylation of remaining terminal amines of the PEI produced a new multifunctional graphene oxide drug carrier (GO/PEI.Ac-FI-PEG-LA). Doxorubicin (DOX), an anticancer drug, was encapsulated in GO/PEI.Ac-FI-PEG-LA to give GO/PEI.Ac-FI-PEG-LA/DOX, with a drug loading percentage of 85%. We showed that both GO/PEI.Ac-FI-PEG-LA and GO/PEI.Ac-FI-PEG-LA/DOX were water soluble and stable between pH 5.0 and 9.0. In vitro release studies indicated that the release rate of DOX from GO/PEI.Ac-FI-PEG-LA/DOX complexes were significantly higher at pH5.8 than that of the physiological pH. Another important feature of this carrier is its good cell viability in the tested concentration range (0-4μM), and the GO/PEI.Ac-FI-PEG-LA/DOX can specifically target cancer cells overexpressing asialoglycoprotein (ASGPR) receptors and exert growth inhibition effect to the cancer cells. The enhanced target specificity and the substantial improvement in pH responsive controlled release have made this new carrier a potential choice for non-covalent encapsulation of drugs in GO, and a delivery system for cancer therapy. PMID:26652419

  17. Experimental observations of thermal spikes in microwave processing of ceramic oxide fibers

    SciTech Connect

    Vogt, G.J.; Unruh, W.P.; Thomas, J.R. Jr.

    1994-04-01

    Microwave heating of alumina/silica fiber tows in a single-mode microwave cavity at 2.45 GHz have produced a surprising thermal spike behavior on the fiber bundles. During a thermal spike, a ``hot spot`` on the tow brightens rapidly, persists for a few seconds, and rapidly extinguishs. A hot spot can encompass the entire tow in the cavity or just a localized portion of the tow. Some local hot spots propagate along the fiber. Thermal spikes are triggered by relatively small (<15%) increases in power, thus having obvious implications for the development of practical microwave fiber processing systems. A tow can be heated through several successive thermal spikes, after which the tow is left substantially cooler than it was originally, although the applied microwave electric field is much larger. X-ray diffraction studies show that after each temperature spike there is a partial phase transformation of the tow material into mullite. After several excursions the tow has been largely transformed to the new, less lossy phase and is more difficult to heat. Heating experiments with Nextel 550 tows are examined for a pausible explanation of this microwave heating behavior.

  18. Dimethylarginine dimethylaminohydrolase: a new therapeutic target for the modulation of nitric oxide and angiogenesis.

    PubMed

    Singh, Jai Pal

    2007-09-01

    Nitric oxide (NO) has a key role in promoting angiogenesis by increasing vasodilation, vascular permeability, endothelial cell proliferation and migration, and by modifying the activities of angiogenic mediators. NO is also critical for the mobilization of endothelial progenitor cells from the bone marrow which promotes vasculogenesis and angiogenesis. Studies have shown that the enzymes catalyzing NO synthesis are inhibited by the endogenously generated inhibitor asymmetric dimethylarginine (ADMA). Pharmacological agents targeted to modulate dimethyl-arginine dimethylaminohydrolase, the key enzyme metabolizing ADMA, may offer a potential strategy for developing novel pro- and anti-angiogenic therapies. PMID:17729185

  19. Soluble fiber-enriched diets improve inflammation and oxidative stress biomarkers in Zucker fatty rats.

    PubMed

    Sánchez, David; Quiñones, Mar; Moulay, Leila; Muguerza, Begoña; Miguel, Marta; Aleixandre, Amaya

    2011-07-01

    In this study we evaluated the effect of the administration of different soluble fiber enriched-diets on inflammatory and redox state of Zucker fatty rats. Four groups of ten 8 week-old female Zucker fatty rats were used. The four groups were respectively fed the following diets until the 15th week of life: standard diet (obese control), 10% high methoxylated apple pectin (HMAP)-, 5% soluble cocoa fiber (SCF)-, and 10% β-glucan-enriched diets. A group of Zucker lean rats fed the standard diet was also used as control for normal values of this rat strain. The plasma levels of tumoral necrosis factor-α (TNF-α), adiponectin, and malondialdehyde (MDA) were measured at the end of treatment. The reduced glutathione liver levels were also obtained at that moment. TNF-α plasma levels decreased somewhat in Zucker fatty rats fed the different fibers, and MDA plasma levels significantly decreased in these animals. Nevertheless, adiponectin plasma levels increased in the Zucker fatty rats fed the SCF enriched diet, but did not change in the HMAP and the β-glucan group. The Zucker fatty rats fed the different fiber showed a trend towards increased the reduced glutathione liver levels, but significant differences with obese control rats were only obtained in the β-glucan group. The results obtained in this study suggest that the intake of the different soluble fiber-enriched diets that we have evaluated could prevent and/or attenuate the inflammatory and/or the prooxidative state of the metabolic syndrome. PMID:21349333

  20. Functionalized magnetic iron oxide/alginate core-shell nanoparticles for targeting hyperthermia.

    PubMed

    Liao, Shih-Hsiang; Liu, Chia-Hung; Bastakoti, Bishnu Prasad; Suzuki, Norihiro; Chang, Yung; Yamauchi, Yusuke; Lin, Feng-Huei; Wu, Kevin C-W

    2015-01-01

    Hyperthermia is one of the promising treatments for cancer therapy. However, the development of a magnetic fluid agent that can selectively target a tumor and efficiently elevate temperature while exhibiting excellent biocompatibility still remains challenging. Here a new core-shell nanostructure consisting of inorganic iron oxide (Fe3O4) nanoparticles as the core, organic alginate as the shell, and cell-targeting ligands (ie, D-galactosamine) decorated on the outer surface (denoted as Fe3O4@Alg-GA nanoparticles) was prepared using a combination of a pre-gel method and coprecipitation in aqueous solution. After treatment with an AC magnetic field, the results indicate that Fe3O4@Alg-GA nanoparticles had excellent hyperthermic efficacy in a human hepatocellular carcinoma cell line (HepG2) owing to enhanced cellular uptake, and show great potential as therapeutic agents for future in vivo drug delivery systems. PMID:26005343

  1. Targeted diazeniumdiolates: localized nitric oxide release from glioma-specific peptides and proteins.

    PubMed

    Safdar, Shahana; Taite, Lakeshia J

    2012-01-17

    Nitric oxide (NO) is a small yet important biological messenger, which at sufficient concentrations has been shown to induce apoptosis as well as increase radiosensitization in tumor cells. However, the short half-life of NO gas itself has limited its utility as a therapeutic agent. The objective of this study was the development of targeted NO donors and we illustrate their utility as a potential therapeutic for treatment of glioblastoma multiforme, the most common and aggressive malignant primary brain tumor in adults. We have synthesized two diazeniumdiolate NO donors by reacting NO gas with glioma-specific targeting sequences, VTWTPQAWFQWVGGGSKKKKK (VTW) and chlorotoxin (CTX), and achieved repeatable NO release from both donors. FITC-labeled biomolecules, when incubated with glioma and control cells preferentially bound to the glioma cells and showed only minimal binding to the control cells. Additionally, tumor cell viability was significantly decreased when cells were incubated with the NO donors whereas control cell viability was not affected. PMID:22101282

  2. Functionalized magnetic iron oxide/alginate core-shell nanoparticles for targeting hyperthermia

    PubMed Central

    Liao, Shih-Hsiang; Liu, Chia-Hung; Bastakoti, Bishnu Prasad; Suzuki, Norihiro; Chang, Yung; Yamauchi, Yusuke; Lin, Feng-Huei; Wu, Kevin C-W

    2015-01-01

    Hyperthermia is one of the promising treatments for cancer therapy. However, the development of a magnetic fluid agent that can selectively target a tumor and efficiently elevate temperature while exhibiting excellent biocompatibility still remains challenging. Here a new core-shell nanostructure consisting of inorganic iron oxide (Fe3O4) nanoparticles as the core, organic alginate as the shell, and cell-targeting ligands (ie, D-galactosamine) decorated on the outer surface (denoted as Fe3O4@Alg-GA nanoparticles) was prepared using a combination of a pre-gel method and coprecipitation in aqueous solution. After treatment with an AC magnetic field, the results indicate that Fe3O4@Alg-GA nanoparticles had excellent hyperthermic efficacy in a human hepatocellular carcinoma cell line (HepG2) owing to enhanced cellular uptake, and show great potential as therapeutic agents for future in vivo drug delivery systems. PMID:26005343

  3. Targeted gold-coated iron oxide nanoparticles for CD163 detection in atherosclerosis by MRI

    PubMed Central

    Tarin, Carlos; Carril, Monica; Martin-Ventura, Jose Luis; Markuerkiaga, Irati; Padro, Daniel; Llamas-Granda, Patricia; Moreno, Juan Antonio; García, Isabel; Genicio, Nuria; Plaza-Garcia, Sandra; Blanco-Colio, Luis Miguel; Penades, Soledad; Egido, Jesus

    2015-01-01

    CD163 is a membrane receptor expressed by macrophage lineage. Studies performed in atherosclerosis have shown that CD163 expression is increased at inflammatory sites, pointing at the presence of intraplaque hemorrhagic sites or asymptomatic plaques. Hence, imaging of CD163 expressing macrophages is an interesting strategy in order to detect atherosclerotic plaques. We have prepared a targeted probe based on gold-coated iron oxide nanoparticles vectorized with an anti-CD163 antibody for the specific detection of CD163 by MRI. Firstly, the specificity of the targeted probe was validated in vitro by incubation of the probe with CD163(+) or (−) macrophages. The probe was able to selectively detect CD163(+) macrophages both in human and murine cells. Subsequently, the targeted probe was injected in 16 weeks old apoE deficient mice developing atherosclerotic lesions and the pararenal abdominal aorta was imaged by MRI. The accumulation of probe in the site of interest increased over time and the signal intensity decreased significantly 48 hours after the injection. Hence, we have developed a highly sensitive targeted probe capable of detecting CD163-expressing macrophages that could provide useful information about the state of the atheromatous lesions. PMID:26616677

  4. Superparamagnetic iron oxide nanoparticles as a dual imaging probe for targeting hepatocytes in vivo.

    PubMed

    Lee, Chang-Moon; Jeong, Hwan-Jeong; Kim, Eun-Mi; Kim, Dong Wook; Lim, Seok Tae; Kim, Hyoung Tae; Park, In-Kyu; Jeong, Yong Yeon; Kim, Jin Woong; Sohn, Myung-Hee

    2009-12-01

    Hepatocyte-specific targeting agents are useful for evaluation of the hepatocytic function and the monitoring of disease progress. Superparamagnetic iron oxide nanoparticles (SPION) bearing terminal galactose groups exhibit a high affinity for the asialoglycoprotein receptor on the hepatocyte surface. In this study, we synthesized and characterized the dual probe SPION detectable by both nuclear and MR imaging modality for specifically targeting hepatocytes in vivo. SPION with 12-nm diameter were functionalized with dopamine. Surface modification of the SPION was performed to target asialoglycoprotein receptor on hepatocytes, using lactobionic acid. Transmission electron microscope images demonstrated that SPION displayed highly uniform characteristics in terms of both particle size and shape. The X-ray diffraction pattern of SPION revealed a nanocrystal structure of magnetite. To radiolabel the magnetite with (99m)Tc, diethylenetriaminepentaacetic acid was conjugated to unreacted functional groups of dopamine. (99m)Tc-labeled lactobionic acid-SPION showed high accumulation in liver, with 38.43 +/- 6.45% injected dose per gram. In MR imaging, the reduction of the T(2) signal in the liver by lactobionic acid-SPION was approximately 50.8 +/- 7.3%. Competition studies and transmission electron microscope images of liver tissues demonstrated that the lactobionic acid-SPION were localized in hepatocytes. Therefore, the lactobionic acid-SPION may be used as a hepatocyte-targeted dual contrast agent for both nuclear and MR imaging. PMID:19859969

  5. Polyethylene Glycol Modified, Cross-Linked Starch Coated Iron Oxide Nanoparticles for Enhanced Magnetic Tumor Targeting

    PubMed Central

    Cole, Adam J.; David, Allan E.; Wang, Jianxin; Galbán, Craig J.; Hill, Hannah L.; Yang, Victor C.

    2010-01-01

    While successful magnetic tumor targeting of iron oxide nanoparticles has been achieved in a number of models, the rapid blood clearance of magnetically suitable particles by the reticuloendothelial system (RES) limits their availability for targeting. This work aimed to develop a long-circulating magnetic iron oxide nanoparticle (MNP) platform capable of sustained tumor exposure via the circulation and, thus, enhanced magnetic tumor targeting. Aminated, cross-linked starch (DN) and aminosilane (A) coated MNPs were successfully modified with 5 kDa (A5, D5) or 20 kDa (A20, D20) polyethylene glycol (PEG) chains using simple N-Hydroxysuccinimide (NHS) chemistry and characterized. Identical PEG-weight analogues between platforms (A5 & D5, A20 & D20) were similar in size (140–190 nm) and relative PEG labeling (1.5% of surface amines – A5/D5, 0.4% – A20/D20), with all PEG-MNPs possessing magnetization properties suitable for magnetic targeting. Candidate PEG-MNPs were studied in RES simulations in vitro to predict long-circulating character. D5 and D20 performed best showing sustained size stability in cell culture medium at 37°C and 7 (D20) to 10 (D5) fold less uptake in RAW264.7 macrophages when compared to previously targeted, unmodified starch MNPs (D). Observations in vitro were validated in vivo, with D5 (7.29 hr) and D20 (11.75 hr) showing much longer half-lives than D (0.12 hr). Improved plasma stability enhanced tumor MNP exposure 100 (D5) to 150 (D20) fold as measured by plasma AUC0-∞ Sustained tumor exposure over 24 hours was visually confirmed in a 9L-glioma rat model (12 mg Fe/kg) using magnetic resonance imaging (MRI). Findings indicate that both D5 and D20 are promising MNP platforms for enhanced magnetic tumor targeting, warranting further study in tumor models. PMID:21176955

  6. Application of a β-cyclodextrin/graphene oxide-modified fiber for solid-phase microextraction of six fragrance allergens in personal products.

    PubMed

    Hou, Xiudan; Wang, Licheng; Tang, Xiaofen; Xiong, Chunming; Guo, Yong; Liu, Xia

    2015-10-01

    A new β-cyclodextrin/graphene oxide hybrid material prepared via a chemical covalent interaction and layer-to-layer assembly was developed as a sorbent for the solid-phase microextraction of fragrance allergens. As a result of its ultra-large surface area, large delocalized π-electron system and abundant hydroxyls, the β-cyclodextrin/graphene oxide-coated fiber could be used to extract particular compounds via strong π-π interactions, van der Waals forces and hydrogen bonding interactions. β-Cyclodextrin with a hydrophobic interior cavity and hydrophilic peripheral face was conducive in extracting the fragrances with hydrophobic and hydrophilic groups. Under the optimized extraction and desorption conditions, the β-cyclodextrin/graphene oxide-coated fiber showed acceptable extraction efficiency for hydrophilic and hydrogen-bonding-donating alcohols. Compared with other methods based on different coating fibers, the proposed fiber obtained wide linear ranges for fragrances with correlation coefficients ranging from 0.9921 to 0.9970, and low limits of detection in the range of 0.050-0.150 μg L(-1). The obtained results indicated that the newly developed fiber was a selective, feasible and cost-effective microextraction medium and could be successfully applied for the determination of several fragrances in personal products. PMID:26332186

  7. Study of uranium oxide milling in order to obtain nanostructured UCx target

    NASA Astrophysics Data System (ADS)

    Guillot, Julien; Tusseau-Nenez, Sandrine; Roussière, Brigitte; Barré-Boscher, Nicole; Brisset, François; Mhamed, Maher Cheikh; Lau, Christophe; Nowak, Sophie

    2016-05-01

    A R&D program is developed at the ALTO facility to provide new beams of exotic neutron-rich nuclei, as intense as possible. In the framework of European projects, it has been shown that the use of refractory targets with nanometric structure allows us to obtain beams of nuclei unreachable until now. The first parameter to be controlled in the processing to obtain targets with a homogeneous nanostructure is the grinding of uranium dioxide, down to 100 nm grain size. In this study, dry and wet grinding routes are studied and the powders are analyzed in terms of phase stabilization, specific surface area and grain morphology. It appears that the grinding, as well dry as wet, leads to the decrease of the particle size. The oxidation of UO2 is observed whatever the grinding. However, the dry grinding is the most efficient and leads to the oxidation of UO2 into U4O9 and U3O7 whose quantities increase with the grinding time while crystallite sizes decrease.

  8. Atomic layer deposition of metal oxide patterns on nonwoven fiber mats using localized physical compression.

    PubMed

    Sweet, William J; Oldham, Christopher J; Parsons, Gregory N

    2014-06-25

    Patterning is an essential part of many industrial processes from printing to semiconductor manufacturing. In this work, we demonstrate a new method to pattern and selectively coat nonwoven textiles by atomic layer deposition (ALD) using compressive mask patterning. A physical mask combined with mechanical compression allows lateral definition and fidelity of the ALD coating to be controlled. We produce features of several sizes on different nonwoven fiber materials and demonstrate the ability to limit diffusion effects to within <200 μm of the pattern edge. Lateral and vertical penetration of reactive growth species into nonwoven mats is investigated by plan-view and cross-sectional imaging. Vertical growth is also analyzed by imaging coating depth into fiber mat stacks. We develop a fully quantitative transport model that describes well the effect of fiber structure and mechanical compression on the extent of coating under the physical mask. This method could be implemented for high-volume patterning for applications including flexible electronics. PMID:24850237

  9. Enhanced microbial decolorization of methyl red with oxidized carbon fiber as redox mediator.

    PubMed

    Emilia Rios-Del Toro, E; Celis, Lourdes B; Cervantes, Francisco J; Rangel-Mendez, J Rene

    2013-09-15

    The anaerobic degradation of azo dyes under anaerobic conditions is possible but at a slow rate. Redox mediators (quinones, activated carbon) are used to improve the reduction rate. The aim of this work was to use activated carbon fiber (ACF) as a redox mediator for the anaerobic reduction of the azo dye methyl red. ACF was chemically modified with 8M HNO₃ to increase its redox-mediating capacity and used in chemical and anaerobic biological batch assays for the reduction of methyl red. ACF increased its redox-mediating capacity up to 3-fold in chemical assays; in biological assays ACF increased the reduction rate up to 8-fold compared to controls without ACF. However, since the ACF served as support for biomass, a biofilm formed on the fiber significantly reduced its redox-mediating capacity; substrate consumption suggested that the electron transport from ACF to methyl red was the rate-limiting step in the process. These results are the first evidence of the role of ACF as a redox mediator in the reductive decolorization of methyl red, in addition to the effect of biofilm attached to ACF on methyl red reduction. Due to the versatile characteristics of ACF and its redox-mediating capacity, carbon fibers could be used in biological wastewater treatment systems to accelerate the reductive transformation of pollutants commonly found in industrial effluents. PMID:23892163

  10. MicroRNAs: New players in cancer prevention targeting Nrf2, oxidative stress and inflammatory pathways

    PubMed Central

    Zhang, Chengyue; Shu, Limin; Kong, Ah-Ng Tony

    2015-01-01

    miRNAs are endogenous small non-coding RNAs of 20-22 nucleotides that repress gene expression at the post-transcriptional level. There is growing interest in the role of miRNAs in cancer chemoprevention, and several naturally occurring chemopreventive agents have been found to be modulators of miRNA expression both in vitro and in vivo. Moreover, these chemopreventive phytochemicals commonly possess anti-oxidative and/or anti-inflammatory properties, and Nrf2 has been extensively studied as a molecular target in cancer prevention. The crosstalk between miRNAs and the traditional cellular signaling pathways of chemoprevention remain to be fully elucidated. This review summarizes the data regarding the potential interactions between miRNAs and anti-oxidative and anti-inflammatory pathways. Cellular redox homeostasis can affect the biogenesis and processing of miRNAs, which in turn regulate the Nrf2 pathway of detoxifying/anti-oxidative genes. We also discuss the miRNA regulatory mechanisms in relation to inflammation-related cancer signaling pathways. PMID:26618104

  11. Increased resistance to oxidative stress in transgenic plants by targeting mannitol biosynthesis to chloroplasts

    SciTech Connect

    Shen, B.; Jensen, R.G.; Bohnert, H.J.

    1997-04-01

    To investigate the potential role of a polyol, mannitol, in oxidative stress protection, a bacterial mannitol-1-phosphate dehydrogenase gene was targeted to chloroplasts by the addition of an aminoterminal transit peptide. Transgenic tobacco (Nicotiana tabacum) lines accumulate mannitol at concentrations ranging from 2.5 to 7 {mu}mol/g fresh weight. Line BS1-31 accumulated approximately 100 mm mannitol in chloroplasts and was identical to the wild type in phenotype and photosynthetic performance. The presence of mannitol in chloroplasts resulted in an increased resistance to methyl viologen (MV)-induced oxidative stress, documented by the increased retention of chlorophyll in transgenic leaf tissue following MV treatment. In the presence of MV, isolated mesophyll cells of BS1-31 exhibited higher CO{sub 2} fixation than the wild type. When the hydroxyl radical probe dimethyl sulfoxide was introduced into cells, the initial formation rate of methane sulfinic acid was significantly lower in cells containing mannitol in the chloroplast compartment than in wild-type cells, indicating an increased hydroxyl radical-scavenging capacity in BS1-31 tobacco. We suggest that the chloroplast location of mannitol can supplement endogenous radical-scavenging mechanisms and reduce oxidative damage of cells by hydroxyl radicals. 43 refs., 5 figs., 1 tab.

  12. Selective induction of oxidative stress in cancer cells via synergistic combinations of agents targeting redox homeostasis.

    PubMed

    Akladios, Fady N; Andrew, Scott D; Parkinson, Christopher J

    2015-07-01

    Cancer cell resistance to chemotherapy is still a heavy burden that impairs the response of many cancer patients to conventional chemotherapy. Using drug combinations is one therapeutic approach to overcome the developing resistance to any one drug. Oxidative stress is now a generally regarded hallmark of cancer that can be one approach to selectively target cancer cells while sparing normal cells. With the aim of increasing oxidative stress in cancer cells to a lethal set point, we have generated and combined several series of redox active compounds that act at different points of the cellular oxidative cascade. The premise of such combinations is to deplete of endogenous antioxidant defence proteins (e.g., Glutathione) while concomitantly increasing the generation of ROS via metal redox recycling and Fenton chemistry which eventually leads to the disruption of cellular redox homeostasis and induction of cell death. Through this approach, we have identified highly synergistic combinations of two distinctive classes of compounds (Azines and Copper(II) complexes of 2-pyridyl ketone thiosemicarbazones) which are capable of eliminating cancer cells without concomitant increase in toxicity toward normal cells. In one of our most potent combinations, a combination index (CI) value of 0.056 was observed, representing a 17 fold enhancement in activity beyond additive effects. Such new combination regimen of redox active compounds can be one step closer to potentially safer low dose chemotherapy. PMID:26022081

  13. Folatereceptor targeted, carboxymethyl chitosan functionalized iron oxide nanoparticles: a novel ultradispersed nanoconjugates for bimodal imaging

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Dipsikha; Das, Manasmita; Mishra, Debashis; Banerjee, Indranil; Sahu, Sumanta K.; Maiti, Tapas K.; Pramanik, Panchanan

    2011-04-01

    This article delineates the design and synthesis of a novel, bio-functionalized, magneto-fluorescent multifunctional nanoparticles suitable for cancer-specific targeting, detection and imaging. Biocompatible, hydrophilic, magneto-fluorescent nanoparticles with surface-pendant amine, carboxyl and aldehyde groups were designed using o-carboxymethyl chitosan (OCMC). The free aminegroups of OCMC stabilized magnetite nanoparticles on the surface allow for the covalent attachment of a fluorescent dye such as rhodamine isothiocyanate (RITC) with the aim to develop a magneto-fluorescent nanoprobe for optical imaging. In order to impart specific cancer cell targeting properties, folic acid and its aminated derivative was conjugated onto these magneto-fluorescent nanoparticles using different pendant groups (-NH2, -COOH, -CHO). These newly synthesized iron-oxide folate nanoconjugates (FA-RITC-OCMC-SPIONs) showed excellent dispersibility, biocompatibility and good hydrodynamic sizes under physiological conditions which were extensively studied by a variety of complementary techniques. The cellular internalization efficacy of these folate-targeted and its non-targeted counterparts were studied using a folate-overexpressed (HeLa) and a normal (L929fibroblast) cells by fluorescence microscopy and magnetically activated cell sorting (MACS). Cell-uptake behaviors of nanoparticles clearly demonstrate that cancer cells over-expressing the human folatereceptor internalized a higher level of these nanoparticle-folate conjugates than normal cells. These folate targeted nanoparticles possess specific magnetic properties in the presence of an external magnetic field and the potential of these nanoconjugates as T2-weighted negative contrast MR imaging agent were evaluated in folate-overexpressed HeLa and normal L929fibroblastcells.

  14. Targeted Iron-Oxide Nanoparticle for Photodynamic Therapy and Imaging of Head and Neck Cancer

    PubMed Central

    2015-01-01

    Photodynamic therapy (PDT) is a highly specific anticancer treatment modality for various cancers, particularly for recurrent cancers that no longer respond to conventional anticancer therapies. PDT has been under development for decades, but light-associated toxicity limits its clinical applications. To reduce the toxicity of PDT, we recently developed a targeted nanoparticle (NP) platform that combines a second-generation PDT drug, Pc 4, with a cancer targeting ligand, and iron oxide (IO) NPs. Carboxyl functionalized IO NPs were first conjugated with a fibronectin-mimetic peptide (Fmp), which binds integrin β1. Then the PDT drug Pc 4 was successfully encapsulated into the ligand-conjugated IO NPs to generate Fmp-IO-Pc 4. Our study indicated that both nontargeted IO-Pc 4 and targeted Fmp-IO-Pc 4 NPs accumulated in xenograft tumors with higher concentrations than nonformulated Pc 4. As expected, both IO-Pc 4 and Fmp-IO-Pc 4 reduced the size of HNSCC xenograft tumors more effectively than free Pc 4. Using a 10-fold lower dose of Pc 4 than that reported in the literature, the targeted Fmp-IO-Pc 4 NPs demonstrated significantly greater inhibition of tumor growth than nontargeted IO-Pc 4 NPs. These results suggest that the delivery of a PDT agent Pc 4 by IO NPs can enhance treatment efficacy and reduce PDT drug dose. The targeted IO-Pc 4 NPs have great potential to serve as both a magnetic resonance imaging (MRI) agent and PDT drug in the clinic. PMID:24923902

  15. Oxidation effects on the mechanical properties of SiC fiber-reinforced reaction-bonded silicon nitride matrix composites

    NASA Technical Reports Server (NTRS)

    Bhatt, Ramakrishna T.

    1989-01-01

    The room temperature mechanical properties of SiC fiber reinforced reaction bonded silicon nitride composites were measured after 100 hrs exposure at temperatures to 1400 C in nitrogen and oxygen environments. The composites consisted of approx. 30 vol percent uniaxially aligned 142 micron diameter SiC fibers in a reaction bonded Si3N4 matrix. The results indicate that composites heat treated in a nitrogen environment at temperatures to 1400 C showed deformation and fracture behavior equivalent to that of the as-fabricated composites. Also, the composites heat treated in an oxidizing environment beyond 400 C yielded significantly lower tensile strength values. Specifically in the temperature range from 600 to 1000 C, composites retained approx. 40 percent of their as-fabricated strength, and those heat treated in the temperatures from 1200 to 1400 C retained 70 percent. Nonetheless, for all oxygen heat treatment conditions, composite specimens displayed strain capability beyond the matrix fracture stress; a typical behavior of a tough composite.

  16. Synergistic effect of Ag nanoparticle-decorated graphene oxide and carbon fiber on electrical actuation of polymeric shape memory nanocomposites

    NASA Astrophysics Data System (ADS)

    Lu, Haibao; Liang, Fei; Gou, Jihua; Leng, Jinsong; Du, Shanyi

    2014-08-01

    This study reports an effective approach of significantly improving electrical properties and recovery performance of shape memory polymer (SMP) nanocomposite, of which its shape recovery was triggered by electrically resistive Joule heating. Reduced graphene oxide (GOs) self-assembled and grafted onto carbon fiber, were used to enhance the interfacial bonding with the SMP matrix via van der Waals force and covalent bond, respectively. A layer of Ag nanoparticles was synthesized from Ag+ solution and chemically deposited onto GO assemblies. These Ag nanoparticles were expected to bridge the gap between GO and improve the electrical conductivity. The experimental results reveal that the electrical conductivity of the SMP nanocomposite was significantly improved via the synergistic effect between Ag nanoparticle-decorated GO and carbon fiber. Finally, the electrically induced shape memory effect of the SMP nanocomposite was achieved, and the temperature distribution in the SMP nanocomposites was recorded and monitored. An effective approach was demonstrated to produce the electro-activated SMP nanocomposites and the resistive Joule heating was viable at a low electrical voltage below 10 V.

  17. Microwave-assisted combustion synthesis of nano iron oxide/iron-coated activated carbon, anthracite, cellulose fiber, and silica, with arsenic adsorption studies

    EPA Science Inventory

    Combustion synthesis of iron oxide/iron coated carbons such as activated carbon, anthracite, cellulose fiber and silica is described. The reactions were carried out in alumina crucibles using a Panasonic kitchen microwave with inverter technology, and the reaction process was com...

  18. Experimental investigation on laser milling of aluminium oxide using a 30 W Q-switched Yb:YAG fiber laser

    NASA Astrophysics Data System (ADS)

    Leone, C.; Genna, S.; Tagliaferri, F.; Palumbo, B.; Dix, M.

    2016-01-01

    In the present study, laser milling tests were carried out on aluminium oxide (Al2O3) plate, 3 mm in thickness, using a Q-Switched 30 W Yb:YAG fiber laser. A systematic approach based on Design of Experiment (DoE) has been successfully adopted with the aim to detect which and how the process parameters affect the laser beam-material interaction, and to explain the effect of the process parameters on the material removal rate and surface quality. The examined process parameters were the laser beam scan speed, the pulse frequency, the total energy released for surface unit, the distance between two consecutive scan lines and the scanning strategy. A full factorial design and ANalysis Of VAriance (ANOVA) were applied for the results analysis. Finally, the various effects of the process parameters on the material removal rate and surface roughness have been analysed and discussed.

  19. Tissue distribution and real-time fluorescence measurement of a tumor-targeted nanodevice by a two photon optical fiber fluorescence probe

    NASA Astrophysics Data System (ADS)

    Thomas, Thommey P.; Ye, Jing Yong; Yang, Chu-Sheng; Myaing, Monthiri; Majoros, Istvan J.; Kotlyar, Alina; Cao, Zhengyi; Norris, Theodore B.; Baker, James R., Jr.

    2006-02-01

    Real-time fluorescence measurement in deep tumors in live animals (or humans) by conventional methods has significant challenges. We have developed a two-photon optical fiber fluorescence (TPOFF) probe as a minimally invasive technique for quantifying fluorescence in solid tumors in live mice. Here we demonstrate TPOFF for real-time measurements of targeted drug delivery dynamics to tumors in live mice. 50-femtosecond laser pulses at 800 nm were coupled into a single mode optical fiber and delivered into the tumor through a 27-gauge needle. Fluorescence was collected back through the same fiber, filtered, and detected with photon counting. Biocompatible dendrimer-based nanoparticles were used for targeted delivery of fluorescent materials into tumors. Dendrimers with targeting agent folic acid and fluorescent reporter 6-TAMRA (G5-6T-FA) were synthesized. KB cell tumors expressing high levels of FA receptors were developed in SCID mice. We initially demonstrated the specific uptake of the targeted conjugates into tumor, kidney and liver, using the TPOFF probe. The tumor fluorescence was then taken in live mice at 30 min, 2 h and 24 h with the TPOFF probe. G5-6T-FA accumulated in the tumor with maximum mean levels reaching 673 +/- 67 nM at the 2 h time point. In contrast, the levels of a control, non-targeted conjugate (G5-6T) at 2 h reached a level of only 136 +/- 28 nM in tumors, and decrease quickly. This indicates that the TPOFF probe can be used as a minimally invasive detection system for quantifying the specific targeting of a fluorescent nanodevice on a real-time basis.

  20. Cobinamides Are Novel Coactivators of Nitric Oxide Receptor That Target Soluble Guanylyl Cyclase Catalytic Domain

    PubMed Central

    Sharina, Iraida; Sobolevsky, Michael; Doursout, Marie-Francoise; Gryko, Dorota

    2012-01-01

    Soluble guanylyl cyclase (sGC), a ubiquitously expressed heme-containing receptor for nitric oxide (NO), is a key mediator of NO-dependent processes. In addition to NO, a number of synthetic compounds that target the heme-binding region of sGC and activate it in a NO-independent fashion have been described. We report here that dicyanocobinamide (CN2-Cbi), a naturally occurring intermediate of vitamin B12 synthesis, acts as a sGC coactivator both in vitro and in intact cells. Heme depletion or heme oxidation does not affect CN2-Cbi-dependent activation. Deletion mutagenesis demonstrates that CN2-Cbi targets a new regulatory site and functions though a novel mechanism of sGC activation. Unlike all known sGC regulators that target the N-terminal regulatory regions, CN2-Cbi directly targets the catalytic domain of sGC, resembling the effect of forskolin on adenylyl cyclases. CN2-Cbi synergistically enhances sGC activation by NO-independent regulators 3-(4-amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine (BAY41-2272), 4-[((4-carboxybutyl){2-[(4-phenethylbenzyl)oxy]phenethyl}amino) methyl [benzoic]-acid (cinaciguat or BAY58-2667), and 5-chloro-2-(5-chloro-thiophene-2-sulfonylamino-N-(4-(morpholine-4-sulfonyl)-phenyl)-benzamide sodium salt (ataciguat or HMR-1766). BAY41-2272 and CN2-Cbi act reciprocally by decreasing the EC50 values. CN2-Cbi increases intracellular cGMP levels and displays vasorelaxing activity in phenylephrine-constricted rat aortic rings in an endothelium-independent manner. Both effects are synergistically potentiated by BAY41-2272. These studies uncover a new mode of sGC regulation and provide a new tool for understanding the mechanism of sGC activation and function. CN2-Cbi also offers new possibilities for its therapeutic applications in augmenting the effect of other sGC-targeting drugs. PMID:22171090

  1. Anti-HER2/neu peptide-conjugated iron oxide nanoparticles for targeted delivery of paclitaxel to breast cancer cells

    NASA Astrophysics Data System (ADS)

    Mu, Qingxin; Kievit, Forrest M.; Kant, Rajeev J.; Lin, Guanyou; Jeon, Mike; Zhang, Miqin

    2015-10-01

    Nanoparticles (NPs) for targeted therapy are required to have appropriate size, stability, drug loading and release profiles, and efficient targeting ligands. However, many of the existing NPs such as albumin, liposomes, polymers, gold NPs, etc. encounter size limit, toxicity and stability issues when loaded with drugs, fluorophores, and targeting ligands. Furthermore, antibodies are bulky and this can greatly affect the physicochemical properties of the NPs, whereas many small molecule-based targeting ligands lack specificity. Here, we report the utilization of biocompatible, biodegradable, small (~30 nm) and stable iron oxide NPs (IONPs) for targeted delivery of paclitaxel (PTX) to HER2/neu positive breast cancer cells using an anti-HER2/neu peptide (AHNP) targeting ligand. We demonstrate the uniform size and high stability of these NPs in biological medium, their effective tumour targeting in live mice, as well as their efficient cellular targeting and selective killing in human HER2/neu-positive breast cancer cells.Nanoparticles (NPs) for targeted therapy are required to have appropriate size, stability, drug loading and release profiles, and efficient targeting ligands. However, many of the existing NPs such as albumin, liposomes, polymers, gold NPs, etc. encounter size limit, toxicity and stability issues when loaded with drugs, fluorophores, and targeting ligands. Furthermore, antibodies are bulky and this can greatly affect the physicochemical properties of the NPs, whereas many small molecule-based targeting ligands lack specificity. Here, we report the utilization of biocompatible, biodegradable, small (~30 nm) and stable iron oxide NPs (IONPs) for targeted delivery of paclitaxel (PTX) to HER2/neu positive breast cancer cells using an anti-HER2/neu peptide (AHNP) targeting ligand. We demonstrate the uniform size and high stability of these NPs in biological medium, their effective tumour targeting in live mice, as well as their efficient cellular

  2. Recent Advances in Superparamagnetic Iron Oxide Nanoparticles for Cellular Imaging and Targeted Therapy Research

    PubMed Central

    Wang, Yi-Xiang J.; Xuan, Shouhu; Port, Marc; Idee, Jean-Marc

    2013-01-01

    Advances of nanotechnology have led to the development of nanomaterials with both potential diagnostic and therapeutic applications. Among them, superparamagnetic iron oxide (SPIO) nanoparticles have received particular attention. Over the past decade, various SPIOs with unique physicochemical and biological properties have been designed by modifying the particle structure, size and coating. This article reviews the recent advances in preparing SPIOs with novel properties, the way these physicochemical properties of SPIOs influence their interaction with cells, and the development of SPIOs in liver and lymph nodes magnetic resonance imaging (MRI) contrast. Cellular uptake of SPIO can be exploited in a variety of potential clinical applications, including stem cell and inflammation cell tracking and intra-cellular drug delivery to cancerous cells which offers higher intra-cellular concentration. When SPIOs are used as carrier vehicle, additional advantages can be achieved including magnetic targeting and hyperthermia options, as well as monitoring with MRI. Other potential applications of SPIO include magnetofection and gene delivery, targeted retention of labeled stem cells, sentinel lymph nodes mapping, and magnetic force targeting and cell orientation for tissue engineering. PMID:23621536

  3. Tumor Vasculature Targeting and Imaging in Living Mice with Reduced Graphene Oxide

    PubMed Central

    Shi, Sixiang; Yang, Kai; Hong, Hao; Valdovinos, Hector F.; Nayak, Tapas R.; Zhang, Yin; Theuer, Charles P.; Barnhart, Todd E.; Liu, Zhuang; Cai, Weibo

    2013-01-01

    Graphene-based nanomaterials have attracted tremendous attention in the field of biomedicine due to their intriguing properties. Herein, we report tumor vasculature targeting and imaging in living mice using reduced graphene oxide (RGO), which was conjugated to the anti-CD105 antibody TRC105. The RGO conjugate, 64Cu-NOTA-RGO-TRC105, exhibited excellent stability in vitro and in vivo. Serial positron emission tomography (PET) imaging studies non-invasively assessed the pharmacokinetics and demonstrated specific targeting of 64Cu-NOTA-RGO-TRC105 to 4T1 murine breast tumors in vivo, compared to non-targeted RGO conjugate (64Cu-NOTA-RGO). In vivo (e.g., blocking 4T1 tumor uptake with excess TRC105), in vitro (e.g., flow cytometry), and ex vivo (e.g., histology) experiments confirmed the specificity of 64Cu-NOTA-RGO-TRC105 for tumor vascular CD105. Since RGO exhibits desirable properties for photothermal therapy, the tumor-specific RGO conjugate developed in this work may serve as a promising theranostic agent that integrates imaging and therapeutic components. PMID:23374706

  4. Tumor vasculature targeting and imaging in living mice with reduced graphene oxide.

    PubMed

    Shi, Sixiang; Yang, Kai; Hong, Hao; Valdovinos, Hector F; Nayak, Tapas R; Zhang, Yin; Theuer, Charles P; Barnhart, Todd E; Liu, Zhuang; Cai, Weibo

    2013-04-01

    Graphene-based nanomaterials have attracted tremendous attention in the field of biomedicine due to their intriguing properties. Herein, we report tumor vasculature targeting and imaging in living mice using reduced graphene oxide (RGO), which was conjugated to the anti-CD105 antibody TRC105. The RGO conjugate, (64)Cu-NOTA-RGO-TRC105, exhibited excellent stability in vitro and in vivo. Serial positron emission tomography (PET) imaging studies non-invasively assessed the pharmacokinetics and demonstrated specific targeting of (64)Cu-NOTA-RGO-TRC105 to 4T1 murine breast tumors in vivo, compared to non-targeted RGO conjugate ((64)Cu-NOTA-RGO). In vivo (e.g., blocking 4T1 tumor uptake with excess TRC105), in vitro (e.g., flow cytometry), and ex vivo (e.g., histology) experiments confirmed the specificity of (64)Cu-NOTA-RGO-TRC105 for tumor vascular CD105. Since RGO exhibits desirable properties for photothermal therapy, the tumor-specific RGO conjugate developed in this work may serve as a promising theranostic agent that integrates imaging and therapeutic components. PMID:23374706

  5. Folic acid-conjugated superparamagnetic iron oxide nanoparticles for tumor-targeting MR imaging.

    PubMed

    Li, Lei; Gao, Fumei; Jiang, Weiwei; Wu, Xueliang; Cai, Yuanyuan; Tang, Jintian; Gao, Xueyun; Gao, Fuping

    2016-06-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) have been the subject of extensive research due to their potential biomedical applications. In the present investigation, superparamagnetic FA-PEI-Fe3O4 were successfully prepared and evaluated as a targeted MRI contrast agent. FTIR characteristics, TGA, VSM, and MR imaging confirmed the composition and magnetic properties of the synthesized nanoparticles. TEM showed that FA-PEI-Fe3O4 were spherical in shape and well dispersed. The nanoparticles were superparamagnetic at room temperature with a saturation magnetization value of 67.1 emu/g. The nanoparticles showed higher uptake efficiency due to receptor-mediated endocytosis. Moreover, specificity of FA-PEI-Fe3O4 to target tumor cells was demonstrated by the increased nanoparticle uptake and significant contrast enhancement of KB cells over MCF7 cells. The competitive inhibition of FA-PEI-Fe3O4 by free FA further confirmed the specific interaction of this conjugate with FA receptors. In vivo MR imaging studies showed a decreased signal intensity and enhanced tumor contrast post-injection of FA-PEI-Fe3O4. These results indicate that FA-PEI-Fe3O4 can be used as a promising tumor-targeting agent as well as a T2 negative-contrast agent in MR imaging applications. PMID:25715808

  6. A graphene oxide based smart drug delivery system for tumor mitochondria-targeting photodynamic therapy.

    PubMed

    Wei, Yanchun; Zhou, Feifan; Zhang, Da; Chen, Qun; Xing, Da

    2016-02-14

    Subcellular organelles play critical roles in cell survival. In this work, a novel photodynamic therapy (PDT) drug delivery and phototoxicity on/off nano-system based on graphene oxide (NGO) as the carrier is developed to implement subcellular targeting and attacking. To construct the nanodrug (PPa-NGO-mAb), NGO is modified with the integrin αvβ3 monoclonal antibody (mAb) for tumor targeting. Pyropheophorbide-a (PPa) conjugated with polyethylene-glycol is used to cover the surface of the NGO to induce phototoxicity. Polyethylene-glycol phospholipid is loaded to enhance water solubility. The results show that the phototoxicity of PPa on NGO can be switched on and off in organic and aqueous environments, respectively. The PPa-NGO-mAb assembly is able to effectively target the αvβ3-positive tumor cells with surface ligand and receptor recognition; once endocytosized by the cells, they are observed escaping from lysosomes and subsequently transferring to the mitochondria. In the mitochondria, the 'on' state PPa-NGO-mAb performs its effective phototoxicity to kill cells. The biological and physical dual selections and on/off control of PPa-NGO-mAb significantly enhance mitochondria-mediated apoptosis of PDT. This smart system offers a potential alternative to drug delivery systems for cancer therapy. PMID:26799192

  7. Mineralized iron oxidizing bacteria from hydrothermal vents: targeting biosignatures on Mars

    NASA Astrophysics Data System (ADS)

    Leveille, R. J.

    2010-12-01

    formation of an iron oxyhydroxide precipitate, either in direct association with the cells or within the growth medium, were observed. Preliminary analyses suggest that these precipitates are different from abiotic precipitates. Continuing work includes high-resolution TEM observations of cultured organisms and biogenic iron minerals, Raman and reflectance spectroscopy of precipitates, examination of seafloor incubation experiments, and bioreactor silicification experiments in order to better understand the Fe-Si fossilization process. Microaerophilic iron oxidation could have existed on the early Earth in environments containing small amounts of oxygen produced either by locally-concentrated photosynthetic microorganisms (e.g., cyanobacteria) or by chemical reactions. By analogy, similar subsurface or near-surface microaerophilic environments could have existed on Mars in the past, including in low-temperature hydrothermal systems. The distinctive morphologies and Fe-Si mineralization patterns of iron oxidizing bacteria could be a useful biosignature to search for on Mars. Deposits and features similar to those described here could be identified on Mars with existing technologies, and thus hydrothermal systems represent an attractive target for future surface and sample return missions.

  8. Optimization of substrate-target distance for pulsed laser deposition of tungsten oxide thin films using Langmuir probe

    NASA Astrophysics Data System (ADS)

    Panda, A. Kumar; Singh, A.; Thirumurugesan, R.; Kuppusami, P.; Mohandas, E.

    2015-09-01

    The paper investigates the spatial and temporal variation of laser produced plasma of tungsten oxide using a Langmuir probe. The plasma was produced by laser ablation of tungsten oxide target using an Excimer laser of wavelength 248 nm. Our experimental studies confirmed that oxygen partial pressure (P) of 2× 10-2 mbar is sufficient enough to get stoichiometric tungsten oxide thin films and the plume dynamics was diagnosed for their spatial and temporal behaviour at the above optimised oxygen pressure. Spatial distribution was recorded with the target to substrate distance (D) ranging from the target position to a distance of 75 mm away from the target, whereas the temporal variation was taken in the range of 0-50 μ S with an interval of 0.5 μ S. The average electron densities were found to be maximum at 30 mm from the target position. However, ion density was constant beyond the probe distance of 45 mm from the target. The plasma current was found to be maximum at 28 μ S. The target to substrate distance was optimized for homogenous adherent good quality thin films using plasma parameters such as ion density and average electron density obtained at different oxygen pressure. The target distance and background gas pressure were correlated as PD scaling law and fitted as PD3 in the model.

  9. Receptor-targeted, drug-loaded, functionalized graphene oxides for chemotherapy and photothermal therapy

    PubMed Central

    Thapa, Raj Kumar; Choi, Ju Yeon; Poudel, Bijay Kumar; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2016-01-01

    Cancer is one of the leading causes of death worldwide. Although different chemotherapeutic agents have been developed to treat cancers, their use can be limited by low cellular uptake, drug resistance, and side effects. Hence, targeted drug delivery systems are continually being developed in order to improve the efficacy of chemotherapeutic agents. The main aim of this study was to prepare folic acid (FA)-conjugated polyvinyl pyrrolidone-functionalized graphene oxides (GO) (FA-GO) for targeted delivery of sorafenib (SF). GO were prepared using a modified Hummer’s method and subsequently altered to prepare FA-GO and SF-loaded FA-GO (FA-GO/SF). Characterization of GO derivatives was done using ultraviolet/visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, atomic force microscopy, zeta potential measurements, and determination of in vitro drug release. Hemolytic toxicity, in vitro cytotoxicity, cellular uptake, and apoptotic effects of FA-GO/SF were also investigated. The results revealed that GO was successfully synthesized and that further transformation to FA-GO improved the stability and SF drug-loading capacity. In addition, the enhanced SF release under acidic conditions suggested possible benefits for cancer treatment. Conjugation of FA within the FA-GO/SF delivery system enabled targeted delivery of SF to cancer cells expressing high levels of FA receptors, thus increasing the cellular uptake and apoptotic effects of SF. Furthermore, the photothermal effect achieved by exposure of GO to near-infrared irradiation enhanced the anticancer effects of FA-GO/SF. Taken together, FA-GO/SF is a potential carrier for targeted delivery of chemotherapeutic agents in cancer. PMID:27358565

  10. Red Fluorescent Zinc Oxide Nanoparticle: A Novel Platform for Cancer Targeting

    PubMed Central

    Hong, Hao; Wang, Fei; Zhang, Yin; Graves, Stephen A.; Eddine, Savo Bou Zein; Yang, Yunan; Theuer, Charles P.; Nickles, Robert J.; Wang, Xudong; Cai, Weibo

    2015-01-01

    Multifunctional zinc oxide (ZnO) nanoparticles (NPs) with well-integrated multimodality imaging capacities have generated increasing research interest in the last decade. However, limited progress has been made in developing ZnO NP-based multimodality tumor-imaging agents. Here we developed novel red fluorescent ZnO NPs and described the successful conjugation of 64Cu (t1/2 = 12.7 h) and TRC105, a chimeric monoclonal antibody against CD105, to these ZnO NPs via well-developed surface engineering procedures. The produced dual-modality ZnO NPs were readily applicable for positron emission tomography (PET) imaging and fluorescence imaging of the tumor vasculature. Their pharmacokinetics and tumor-targeting efficacy/specificity in mice bearing murine breast 4T1 tumor were thoroughly investigated. ZnO NPs with dual-modality imaging properties can serve as an attractive candidate for future cancer theranostics. PMID:25607242

  11. Solvent-Free Click-Mechanochemistry for the Preparation of Cancer Cell Targeting Graphene Oxide.

    PubMed

    Rubio, Noelia; Mei, Kuo-Ching; Klippstein, Rebecca; Costa, Pedro M; Hodgins, Naomi; Wang, Julie Tzu-Wen; Festy, Frederic; Abbate, Vincenzo; Hider, Robert C; Chan, Ka Lung Andrew; Al-Jamal, Khuloud T

    2015-09-01

    Polyethylene glycol-functionalized nanographene oxide (PEGylated n-GO) was synthesized from alkyne-modified n-GO, using solvent-free click-mechanochemistry, i.e., copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The modified n-GO was subsequently conjugated to a mucin 1 receptor immunoglobulin G antibody (anti-MUC1 IgG) via thiol-ene coupling reaction. n-GO derivatives were characterized with Fourier-transformed infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), Bradford assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and atomic force microscopy (AFM). Cell targeting was confirmed in vitro in MDA-MB-231 cells, either expressing or lacking MUC1 receptors, using flow cytometry, confocal laser scanning microscopy (CLSM) and multiphoton (MP) fluorescence microscopy. Biocompatibility was assessed using the modified lactate dehydrongenase (mLDH) assay. PMID:26278410

  12. Pharmaceutical formulation of HSA hybrid coated iron oxide nanoparticles for magnetic drug targeting.

    PubMed

    Zaloga, Jan; Pöttler, Marina; Leitinger, Gerd; Friedrich, Ralf P; Almer, Gunter; Lyer, Stefan; Baum, Eva; Tietze, Rainer; Heimke-Brinck, Ralph; Mangge, Harald; Dörje, Frank; Lee, Geoffrey; Alexiou, Christoph

    2016-04-01

    In this work we present a new formulation of superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic drug targeting. The particles were reproducibly synthesized from current good manufacturing practice (cGMP) - grade substances. They were surface coated using fatty acids as anchoring molecules for human serum albumin. We comprehensively characterized the physicochemical core-shell structure of the particles using sophisticated methods. We investigated biocompatibility and cellular uptake of the particles using an established flow cytometric method in combination with microwave-plasma assisted atomic emission spectroscopy (MP-AES). The cytotoxic drug mitoxantrone was adsorbed on the protein shell and we showed that even in complex media it is slowly released with a close to zero order kinetics. We also describe an in vitro proof-of-concept assay in which we clearly showed that local enrichment of this SPION-drug conjugate with a magnet allows site-specific therapeutic effects. PMID:26854862

  13. Solvent-Free Click-Mechanochemistry for the Preparation of Cancer Cell Targeting Graphene Oxide

    PubMed Central

    2015-01-01

    Polyethylene glycol-functionalized nanographene oxide (PEGylated n-GO) was synthesized from alkyne-modified n-GO, using solvent-free click-mechanochemistry, i.e., copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC). The modified n-GO was subsequently conjugated to a mucin 1 receptor immunoglobulin G antibody (anti-MUC1 IgG) via thiol–ene coupling reaction. n-GO derivatives were characterized with Fourier-transformed infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), Bradford assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and atomic force microscopy (AFM). Cell targeting was confirmed in vitro in MDA-MB-231 cells, either expressing or lacking MUC1 receptors, using flow cytometry, confocal laser scanning microscopy (CLSM) and multiphoton (MP) fluorescence microscopy. Biocompatibility was assessed using the modified lactate dehydrongenase (mLDH) assay. PMID:26278410

  14. Surface modified superparamagnetic iron oxide nanoparticles: as a new carrier for bio-magnetically targeted therapy.

    PubMed

    Liang, Sheng; Wang, Yongxian; Yu, Junfeng; Zhang, Chunfu; Xia, Jiaoyun; Yin, Duanzhi

    2007-12-01

    Amino-functionalized superparamagnetic iron oxide nanoparticles (SPION) were synthesized by coprecipitation method. The particles were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron micrographs (SEM), transmission electron micrographs (TEM) and atomic force micrographs (AFM). The size of the modified particles varied in the range 10-15 nm and did not change significantly after modification. Hepama-1, an excellent humanized monoclonal antibody directed against liver cancer, was conjugated to the SPION to prepare immuno-magnetic nanoparticles (IMN). A direct labeling method was employed to radiolabel IMN with rhenium-188. The radiolabeling efficiency was about 90% with good in vitro stability. (188)Re labeled IMN could markedly kill SMMC-7721 liver cancer cells. Such SPION might be very useful for bio-magnetically targeted radiotherapy in liver cancer treatment. PMID:17562137

  15. Red fluorescent zinc oxide nanoparticle: a novel platform for cancer targeting.

    PubMed

    Hong, Hao; Wang, Fei; Zhang, Yin; Graves, Stephen A; Eddine, Savo Bou Zein; Yang, Yunan; Theuer, Charles P; Nickles, Robert J; Wang, Xudong; Cai, Weibo

    2015-02-11

    Multifunctional zinc oxide (ZnO) nanoparticles (NPs) with well-integrated multimodality imaging capacities have generated increasing research interest in the past decade. However, limited progress has been made in developing ZnO NP-based multimodality tumor-imaging agents. Here we developed novel red fluorescent ZnO NPs and described the successful conjugation of 64Cu (t1/2=12.7 h) and TRC105, a chimeric monoclonal antibody against CD105, to these ZnO NPs via well-developed surface engineering procedures. The produced dual-modality ZnO NPs were readily applicable for positron emission tomography (PET) imaging and fluorescence imaging of the tumor vasculature. Their pharmacokinetics and tumor-targeting efficacy/specificity in mice bearing murine breast 4T1 tumor were thoroughly investigated. ZnO NPs with dual-modality imaging properties can serve as an attractive candidate for future cancer theranostics. PMID:25607242

  16. Characterization of PMR-15 polyimide composition in thermo-oxidatively exposed graphite fiber composites

    NASA Technical Reports Server (NTRS)

    Alston, W. B.

    1980-01-01

    The contributions of individual resin components to total resin weight loss in 600 F air aged Celion 6000/PMR-15 polyimide composites were determined from the overall resin weight loss in the composite by chemically separating the PMR-15 matrix resin into its monomeric components. The individual resin components were also analyzed by spectroscopic techniques in order to elucidate curing and degradation mechanisms of the PMR-15 matrix resin. The isothermal weight loss of the individual resin components during prolonged 600 F thermo-oxidative aging of the composite was correlated to the changes observed in the Fourier Transform infrared spectra and Fourier Transform nuclear magnetic resonance spectra of the individual resin components. The correlation was used to identify the molecular site of the thermo-oxidative changes in PMR-15 polyimide matrix resin during 600 F curing the prolonged 600 F thermo-oxidative aging.

  17. Targeting Parkinson's - tyrosine hydroxylase and oxidative stress as points of interventions.

    PubMed

    Khan, Mohd Shahnawa; Tabrez, Shams; Priyadarshini, Medha; Priyamvada, Shubha; Khan, Mohd M

    2012-06-01

    Parkinson's disease (PD) is characterized by the progressive loss of the dopaminergic neurons leading to decrease in striatal dopamine (DA) levels. In the present review, our focus was on recent advances in the treatment procedures of PD to achieve an increase in deficient tyrosine hydroxylase (TH) activity and/or expression. Stimulation of residual TH activity by the cofactors, 6R-L-erythro-tetrahydrobiopterin (BPH4) or NADH, or by brain transplant of natural TH-containing cells (fetal substantia nigra) or genetically engineered TH-containing cells, has been tried experimentally and clinically lately. As a promising approach to the gene therapy, intrastriatal expression of DAsynthesizing enzymes through transduction with separate adeno-associated virus (AAV) vectors/ marrow stromal cells (MSCs) or nonviral intravenous administration of rat transferrin receptor monoclonal antibody (TfRmAb)-targeted PEGylated immunoliposomes (PILs) has been found to be effective in animal models. Oxidative stress has been identified as one of the intermediary risk factors that could initiate and/or promote degeneration of DA neurons. TH itself is a prime target of oxidative/nitrosative injury. Certain superoxide dismutase and catalase mimetic prevented nitration of TH in cultured dopaminergic neurons. Therefore, development of therapeutic agents that can prevent formation of or specifically remove nitrating agents without interfering with normal neuronal function may protect protein from inactivation and provide means of limiting neuronal injury in PD. Non-pharmacological approaches such as diet therapy or use of active constituents of plants and phytomedicines have also emerged as a new - area of high interest. New treatment strategies for TH dysfunction rectification, a provision for neuroprotection in PD, seem to be on the horizon with many therapies under investigation. PMID:22483312

  18. In vivo target bio-imaging of Alzheimer's disease by fluorescent zinc oxide nanoclusters.

    PubMed

    Lai, Lanmei; Zhao, Chunqiu; Su, Meina; Li, Xiaoqi; Liu, Xiaoli; Jiang, Hui; Amatore, Christian; Wang, Xuemei

    2016-07-21

    Alzheimer's disease (AD) is an irreversible neurodegenerative disease which is difficult to cure. When Alzheimer's disease occurs, the level of zinc ions in the brain changes, and the relevant amount of zinc ions continue decreasing in the cerebrospinal fluid and plasma of Alzheimer's patients with disease exacerbation. In view of these considerations, we have explored a new strategy for the in vivo rapid fluorescence imaging of Alzheimer's disease through target bio-labeling of zinc oxide nanoclusters which were biosynthesized in vivo in the Alzheimer's brain via intravenous injection of zinc gluconate solution. By using three-month-old and six-month-old Alzheimer's model mice as models, our observations demonstrate that biocompatible zinc ions could pass through the blood-brain barrier of the Alzheimer's disease mice and generate fluorescent zinc oxide nanoclusters (ZnO NCs) through biosynthesis, and then the bio-synthesized ZnO NCs could readily accumulate in situ on the hippocampus specific region for the in vivo fluorescent labeling of the affected sites. This study provides a new way for the rapid diagnosis of Alzheimer's disease and may have promising prospects in the effective diagnosis of Alzheimer's disease. PMID:27229662

  19. Cuprous oxide nanoparticles inhibit the growth and metastasis of melanoma by targeting mitochondria

    PubMed Central

    Wang, Y; Yang, F; Zhang, H-X; Zi, X-Y; Pan, X-H; Chen, F; Luo, W-D; Li, J-X; Zhu, H-Y; Hu, Y-P

    2013-01-01

    Metal and its oxide nanoparticles show ideal pharmacological activity, especially in anti-tumor therapy. Our previous study demonstrated that cuprous oxide nanoparticles (CONPs) selectively induce apoptosis of tumor cells in vitro. To explore the anti-tumor properties of CONPs in vivo, we used the particles to treat mouse subcutaneous melanoma and metastatic lung tumors, based on B16-F10 mouse melanoma cells, by intratumoral and systemic injections, respectively. The results showed that CONPs significantly reduced the growth of melanoma, inhibited the metastasis of B16-F10 cells and increased the survival rate of tumor-bearing mice. Importantly, the results also indicated that CONPs were rapidly cleared from the organs and that these particles exhibited little systemic toxicity. Furthermore, we observed that CONPs targeted the mitochondria, which resulted in the release of cytochrome C from the mitochondria and the activation of caspase-3 and caspase-9 after the CONPs entered the cells. In conclusion, CONPs can induce the apoptosis of cancer cells through a mitochondrion-mediated apoptosis pathway, which raises the possibility that CONPs could be used to cure melanoma and other cancers. PMID:23990023

  20. Indazole, Pyrazole, and Oxazole Derivatives Targeting Nitric Oxide Synthases and Carbonic Anhydrases.

    PubMed

    Maccallini, Cristina; Di Matteo, Mauro; Vullo, Daniela; Ammazzalorso, Alessandra; Carradori, Simone; De Filippis, Barbara; Fantacuzzi, Marialuigia; Giampietro, Letizia; Pandolfi, Assunta; Supuran, Claudiu T; Amoroso, Rosa

    2016-08-19

    Nitric oxide (NO) is an essential endogenous mediator with a physiological role in the central nervous system as neurotransmitter and neuromodulator. A growing number of studies have demonstrated that abnormal nitrergic signaling is a crucial event in the development of neurodegeneration. In particular, the uncontrolled production of NO by neuronal nitric oxide synthase (nNOS) is observed in several neurodegenerative diseases. Moreover, it is well recognized that specific isoforms of human carbonic anhydrase (hCA) physiologically modulate crucial pathways of signal processing and that low expression of CA affects cognition, leading to mental retardation, Alzheimer's disease, and aging-related cognitive impairments. In light of this, dual agents that are able to target both NOS (inhibition) and CA (activation) could be useful drug candidates for the treatment of Alzheimer's disease, aging, and other neurodegenerative diseases. In the present work, we show the design, synthesis, and in vitro biological evaluation of new nitrogen-based heterocyclic compounds. Among the tested molecules, 2-amino-3-(4-hydroxyphenyl)-N-(1H-indazol-5-yl)propanamide hydrochloride (10 b) was revealed to be a potent dual agent, able to act as a selective nNOS inhibitor and activator of the hCA I isoform. PMID:27377568

  1. Bioinspired Polyelectrolyte-Assembled Graphene-Oxide-Coated C18 Composite Solid-Phase Microextraction Fibers for In Vivo Monitoring of Acidic Pharmaceuticals in Fish.

    PubMed

    Qiu, Junlang; Chen, Guosheng; Liu, Shuqin; Zhang, Tianlang; Wu, Jiayi; Wang, Fuxin; Xu, Jianqiao; Liu, Yan; Zhu, Fang; Ouyang, Gangfeng

    2016-06-01

    A novel solid-phase microextraction (SPME) fiber was prepared by gluing poly(diallyldimethylammonium chloride) (PDDA) assembled graphene oxide (GO)-coated C18 composite particles (C18@GO@PDDA) onto a quartz fiber with polyaniline (PANI). The fiber surface coating was sequentially modified with bioinspired polynorepinephrine, which provided a smooth biointerface and makes the coating suitable for in vivo sampling. The novel custom-made coating was used to extract acidic pharmaceuticals, and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was employed for analysis. The custom-made coating exhibited a much higher extraction efficiency than the previously used commercial polydimethylsiloxane (PDMS) and polyacrylate (PA) coatings. The custom-made coating also possessed satisfactory stability (the relative standard deviations (RSDs) ranged from 1.60% to 10.3% for six sampling-desorption cycles), interfiber reproducibility (the RSDs ranged from 2.61% to 11.5%), and resistance to matrix effects. The custom-made fibers were used to monitor the presence of acid pharmaceuticals in dorsal-epaxial muscle of living fish, and satisfactory sensitivities (limits of detection ranged from 0.13 ng/g to 7.56 ng/g) were achieved. The accuracies were verified by the comparison with liquid extraction. Moreover, the novel fibers were successfully used to monitor the presence of acidic pharmaceuticals in living fish, which demonstrated that the custom-made fibers were feasible for possible long-term in vivo continuous pharmaceutical monitoring. PMID:27189112

  2. Carboxymethyl chitosan-mediated synthesis of hyaluronic acid-targeted graphene oxide for cancer drug delivery.

    PubMed

    Yang, Huihui; Bremner, David H; Tao, Lei; Li, Heyu; Hu, Juan; Zhu, Limin

    2016-01-01

    In order to enhance the efficiency and specificity of anticancer drug delivery and realize intelligently controlled release, a new drug carrier was developed. Graphene oxide (GO) was first modified with carboxymethyl chitosan (CMC), followed by conjugation of hyaluronic acid (HA) and fluorescein isothiocyanate (FI). The resulting GO-CMC-FI-HA conjugate was characterized and used as a carrier to encapsulate the anticancer drug doxorubicin (DOX) to study in vitro release behavior. The drug loading capacity is as high as 95% and the drug release rate under tumor cell microenvironment of pH 5.8 is significantly higher than that under physiological conditions of pH 7.4. Cell uptake studies show that the GO-CMC-FI-HA/DOX complex can specifically target cancer cells, which are over-expressing CD44 receptors and effectively inhibit their growth. The above results suggest that the functionalized graphene-based material has potential applications for targeted delivery and controlled release of anticancer drugs. PMID:26453853

  3. Phagocytes mediate targeting of iron oxide nanoparticles to tumors for cancer therapy

    PubMed Central

    Toraya-Brown, Seiko; Sheen, Mee Rie; Baird, Jason R.; Barry, Stephen; Demidenko, Eugene; Turk, Mary Jo; Hoopes, P Jack; Conejo-Garcia, Jose R.; Fiering, Steven

    2012-01-01

    Nanotechnology has great potential to produce novel therapeutic strategies that target malignant cells through the ability of nanoparticles to get access to and be ingested by living cells. However its specificity for accumulation in tumors, which is the key factor that determines its efficacy, has always been a challenge. Here we tested a novel strategy to target and treat ovarian cancer, a representative peritoneal cancer, using iron oxide nanoparticles (IONPs) and an alternating magnetic field (AMF). Peritoneal tumors in general are directly accessible to nanoparticles administered intraperitoneally (IP), as opposed to the more commonly attempted intravenous (IV) administration. In addition, tumor-associated immunosuppressive phagocytes, a predominant cell population in the tumor microenvironment of almost all solid tumors, and cells that are critical for tumor progression, are constantly recruited to the tumor, and therefore could possibly function to bring nanoparticles to tumors. Here we demonstrate that tumor-associated peritoneal phagocytes ingest and carry IONPs specifically to tumors and that these specifically delivered nanoparticles can damage tumor cells after IONP-mediated hyperthermia generated by AMF. This illustrates therapeutic possibilities of intraperitoneal (IP) injection of nanoparticles and subsequent ingestion by tumor-associated phagocytes, to directly impact tumors or stimulate antitumor immune responses. This approach could use IONPs combined with AMF as done here, or other nanoparticles with cytotoxic potential. Overall, the data presented here support IP injection of nanoparticles to utilize peritoneal phagocytes as a delivery vehicle in association with IONP-mediated hyperthermia as therapeutic strategies for ovarian and other peritoneal cancers. PMID:22935885

  4. Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

    PubMed Central

    Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

    2016-01-01

    The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level. PMID:27271611

  5. Superparamagnetic iron oxide nanoparticles conjugated with epidermal growth factor (SPION–EGF) for targeting brain tumors

    PubMed Central

    Shevtsov, Maxim A; Nikolaev, Boris P; Yakovleva, Ludmila Y; Marchenko, Yaroslav Y; Dobrodumov, Anatolii V; Mikhrina, Anastasiya L; Martynova, Marina G; Bystrova, Olga A; Yakovenko, Igor V; Ischenko, Alexander M

    2014-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) conjugated with recombinant human epidermal growth factor (SPION–EGF) were studied as a potential agent for magnetic resonance imaging contrast enhancement of malignant brain tumors. Synthesized conjugates were characterized by transmission electron microscopy, dynamic light scattering, and nuclear magnetic resonance relaxometry. The interaction of SPION–EGF conjugates with cells was analyzed in a C6 glioma cell culture. The distribution of the nanoparticles and their accumulation in tumors were assessed by magnetic resonance imaging in an orthotopic model of C6 gliomas. SPION–EGF nanosuspensions had the properties of a negative contrast agent with high coefficients of relaxation efficiency. In vitro studies of SPION–EGF nanoparticles showed high intracellular incorporation and the absence of a toxic influence on C6 cell viability and proliferation. Intravenous administration of SPION–EGF conjugates in animals provided receptor-mediated targeted delivery across the blood–brain barrier and tumor retention of the nanoparticles; this was more efficient than with unconjugated SPIONs. The accumulation of conjugates in the glioma was revealed as hypotensive zones on T2-weighted images with a twofold reduction in T2 relaxation time in comparison to unconjugated SPIONs (P<0.001). SPION–EGF conjugates provide targeted delivery and efficient magnetic resonance contrast enhancement of EGFR-overexpressing C6 gliomas. PMID:24421639

  6. Hyaluronic Acid Modified Tantalum Oxide Nanoparticles Conjugating Doxorubicin for Targeted Cancer Theranostics.

    PubMed

    Jin, Yushen; Ma, Xibo; Feng, Shanshan; Liang, Xiao; Dai, Zhifei; Tian, Jie; Yue, Xiuli

    2015-12-16

    Theranostic tantalum oxide nanoparticles (TaOxNPs) of about 40 nm were successfully developed by conjugating functional molecules including polyethylene glycol (PEG), near-infrared (NIR) fluorescent dye, doxorubicin (DOX), and hyaluronic acid (HA) onto the surface of the nanoparticles (TaOx@Cy7-DOX-PEG-HA NPs) for actively targeting delivery, pH-responsive drug release, and NIR fluorescence/X-ray CT bimodal imaging. The obtained nanoagent exhibits good biocompatibility, high cumulative release rate in the acidic microenvironments, long blood circulation time, and superior tumor-targeting ability. Both in vitro and in vivo experiments show that it can serve as an excellent contrast agent to simultaneously enhance fluorescence imaging and CT imaging greatly. Most importantly, such a nanoagent could enhance the therapeutic efficacy of the tumor greatly and the tumor growth inhibition was evaluated to be 87.5%. In a word, multifunctional TaOx@Cy7-DOX-PEG-HA NPs can serve as a theranostic nanomedicine for fluorescence/X-ray CT bimodal imaging, remote-controlled therapeutics, enabling personalized detection, and treatment of cancer with high efficacy. PMID:26554699

  7. Lactobionic acid and carboxymethyl chitosan functionalized graphene oxide nanocomposites as targeted anticancer drug delivery systems.

    PubMed

    Pan, Qixia; Lv, Yao; Williams, Gareth R; Tao, Lei; Yang, Huihui; Li, Heyu; Zhu, Limin

    2016-10-20

    In this work, we report a targeted drug delivery system built by functionalizing graphene oxide (GO) with carboxymethyl chitosan (CMC), fluorescein isothiocyanate and lactobionic acid (LA). Analogous systems without LA were prepared as controls. Doxorubicin (DOX) was loaded onto the composites through adsorption. The release behavior from both the LA-functionalized and the LA-free material is markedly pH sensitive. The modified GOs have high biocompatibility with the liver cancer cell line SMMC-7721, but can induce cell death after 24h incubation if loaded with DOX. Tests with shorter (2h) incubation times were undertaken to investigate the selectivity of the GO composites: under these conditions, neither DOX-loaded system was found to be toxic to the non-cancerous L929 cell line, but the LA-containing composite showed the ability to selectively induce cell death in cancerous (SMMC-7721) cells while the LA-free analogue was inactive here also. These findings show that the modified GO materials are strong potential candidates for targeted anticancer drug delivery systems. PMID:27474628

  8. A novel intermembrane space–targeting signal docks cysteines onto Mia40 during mitochondrial oxidative folding

    PubMed Central

    Sideris, Dionisia P.; Petrakis, Nikos; Katrakili, Nitsa; Mikropoulou, Despina; Gallo, Angelo; Ciofi-Baffoni, Simone; Banci, Lucia; Bertini, Ivano

    2009-01-01

    Mia40 imports Cys-containing proteins into the mitochondrial intermembrane space (IMS) by ensuring their Cys-dependent oxidative folding. In this study, we show that the specific Cys of the substrate involved in docking with Mia40 is substrate dependent, the process being guided by an IMS-targeting signal (ITS) present in Mia40 substrates. The ITS is a 9-aa internal peptide that (a) is upstream or downstream of the docking Cys, (b) is sufficient for crossing the outer membrane and for targeting nonmitochondrial proteins, (c) forms an amphipathic helix with crucial hydrophobic residues on the side of the docking Cys and dispensable charged residues on the other side, and (d) fits complementary to the substrate cleft of Mia40 via hydrophobic interactions of micromolar affinity. We rationalize the dual function of Mia40 as a receptor and an oxidase in a two step–specific mechanism: an ITS-guided sliding step orients the substrate noncovalently, followed by docking of the substrate Cys now juxtaposed to pair with the Mia40 active Cys. PMID:20026652

  9. Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs.

    PubMed

    Dumkova, Jana; Vrlikova, Lucie; Vecera, Zbynek; Putnova, Barbora; Docekal, Bohumil; Mikuska, Pavel; Fictum, Petr; Hampl, Ales; Buchtova, Marcela

    2016-01-01

    The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level. PMID:27271611

  10. A graphene oxide based smart drug delivery system for tumor mitochondria-targeting photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Wei, Yanchun; Zhou, Feifan; Zhang, Da; Chen, Qun; Xing, Da

    2016-02-01

    Subcellular organelles play critical roles in cell survival. In this work, a novel photodynamic therapy (PDT) drug delivery and phototoxicity on/off nano-system based on graphene oxide (NGO) as the carrier is developed to implement subcellular targeting and attacking. To construct the nanodrug (PPa-NGO-mAb), NGO is modified with the integrin αvβ3 monoclonal antibody (mAb) for tumor targeting. Pyropheophorbide-a (PPa) conjugated with polyethylene-glycol is used to cover the surface of the NGO to induce phototoxicity. Polyethylene-glycol phospholipid is loaded to enhance water solubility. The results show that the phototoxicity of PPa on NGO can be switched on and off in organic and aqueous environments, respectively. The PPa-NGO-mAb assembly is able to effectively target the αvβ3-positive tumor cells with surface ligand and receptor recognition; once endocytosized by the cells, they are observed escaping from lysosomes and subsequently transferring to the mitochondria. In the mitochondria, the `on' state PPa-NGO-mAb performs its effective phototoxicity to kill cells. The biological and physical dual selections and on/off control of PPa-NGO-mAb significantly enhance mitochondria-mediated apoptosis of PDT. This smart system offers a potential alternative to drug delivery systems for cancer therapy.Subcellular organelles play critical roles in cell survival. In this work, a novel photodynamic therapy (PDT) drug delivery and phototoxicity on/off nano-system based on graphene oxide (NGO) as the carrier is developed to implement subcellular targeting and attacking. To construct the nanodrug (PPa-NGO-mAb), NGO is modified with the integrin αvβ3 monoclonal antibody (mAb) for tumor targeting. Pyropheophorbide-a (PPa) conjugated with polyethylene-glycol is used to cover the surface of the NGO to induce phototoxicity. Polyethylene-glycol phospholipid is loaded to enhance water solubility. The results show that the phototoxicity of PPa on NGO can be switched on and off in

  11. Nitric Oxide Improves Molecular Imaging of Inflammatory Atheroma using Targeted Echogenic Immunoliposomes

    PubMed Central

    Kim, Hyunggun; Kee, Patrick H.; Rim, Yonghoon; Moody, Melanie R.; Klegerman, Melvin E.; Vela, Deborah; Huang, Shao-Ling; McPherson, David D.; Laing, Susan T.

    2013-01-01

    Objective: This study aimed to demonstrate whether pretreatment with nitric oxide (NO) loaded into echogenic immunoliposomes (ELIP) plus ultrasound, applied before injection of molecularly targeted ELIP can promote penetration of the targeted contrast agent and improve visualization of atheroma components. Methods: ELIP were prepared using the pressurization-freeze method. Atherosclerosis was induced in Yucatan miniswine by balloon denudation and a hyperlipidemic diet. The animals were randomized to receive anti-intercellular adhesion molecule-1 (ICAM-1) ELIP or immunoglobulin (IgG)-ELIP, and were subdivided to receive pretreatment with standard ELIP plus ultrasound, NO-loaded ELIP, or NO-loaded ELIP plus ultrasound. Intravascular ultrasound (IVUS) data were collected before and after treatment. Results: Pretreatment with standard ELIP plus ultrasound or NO-loaded ELIP without ultrasound resulted in 9.2 ± 0.7% and 9.2 ± 0.8% increase in mean gray scale values, respectively, compared to baseline (p<0.001 vs. control). Pretreatment with NO-loaded ELIP plus ultrasound activation resulted in a further increase in highlighting with a change in mean gray scale value to 14.7 ± 1.0% compared to baseline (p<0.001 vs. control). These differences were best appreciated when acoustic backscatter data values (RF signal) were used [22.7 ± 2.0% and 22.4 ± 2.2% increase in RF signals for pretreatment with standard ELIP plus ultrasound and NO-loaded ELIP without ultrasound respectively (p<0.001 vs. control), and 40.0 ± 2.9% increase in RF signal for pretreatment with NO-loaded ELIP plus ultrasound (p<0.001 vs. control)]. Conclusion: NO-loaded ELIP plus ultrasound activation can facilitate anti-ICAM-1 conjugated ELIP delivery to inflammatory components in the arterial wall. This NO pretreatment strategy has potential to improve targeted molecular imaging of atheroma for eventual true tailored and personalized management of cardiovascular diseases. PMID:24267236

  12. Comparative analysis of anodized, implanted and sputtered tantalum oxide targets for the study of 16O+16O fusion reaction

    NASA Astrophysics Data System (ADS)

    Silva, H.; Cruz, J.; Redondo-Cubero, A.; Santos, C.; Fonseca, M.; Luis, H.; Jesus, A. P.

    2014-07-01

    Measuring the total cross section of a fusion reaction in the region of astrophysical interest, such as the 16O+16O fusion reaction, is a real challenge due the very small cross sections involved and the large number of possible exit channels. Taking into account these difficulties, the use of targets with known thickness, stoichiometry and minimal contamination that can withstand high beam currents is required. In this study, we report the comparison between three different types of targets for the study of this fusion reaction, such as anodized, implanted and sputtered tantalum oxide targets and the results show that the anodized and sputtered targets are more suitable for this study due to their higher oxygen density and to the formation of a stable oxide compound, tantalum pentoxide (Ta2O5).

  13. Observation of multipulse bunches in a graphene oxide passively mode-locked ytterbium-doped fiber laser with all-normal dispersion

    NASA Astrophysics Data System (ADS)

    Huang, Shisheng; Wang, Yonggang; Peiguang, Yan; Zhang, Gelin; Zhao, Junqing; Li, Huiquan; Lin, Rongyong; Cao, Guangzhong; Duan, Ji'an

    2014-09-01

    We give a systematic experimental study of multipulse bunches in a graphene oxide saturable absorber (GOSA) passively mode-locked all-normal dispersion ytterbium-doped fiber laser (YDFL). Some special phenomena such as harmonic multipulse bunches, harmonic mode-locking, and chaotic multipulse states are also obtained. Our experiment reveals that the inserted 2.5-nm narrow bandwidth filter plays an important role in the formation of multipulse in all-normal dispersion fiber lasers. Because of the effective gain bandwidth depends on both the 2.5-nm narrow bandwidth filter and the artificial fiber birefringence filter, the multipulse operation states are sensitive to the polarization. It is the first demonstration of multipulse evolution in a GOSA passively mode-locked all-normal dispersion YDFL.

  14. The major pelvic ganglion is the main source of nitric oxide synthase-containing nerve fibers in penile erectile tissue of the rat.

    PubMed

    Ding, Y Q; Wang, Y Q; Qin, B Z; Li, J S

    1993-12-24

    The possible implication of nitric oxide synthase (NOS) in penile erection was examined by utilizing NADPH histochemistry in the rat. NADPH histochemistry indicated that the major pelvic ganglion (MPG), a well-known origin of nerve fibers supplying the external genitalia, contained many NOS-positive neurons. On the other hand, NOS-positive nerve fibers in penile erectile tissue observed in the walls of both arteries and veins, as well as in intrinsic smooth muscles. The retrograde tracing study with Fluoro-Gold (FG) in combination with NADPH histochemistry revealed that almost all MPG neurons which were retrogradely labeled with FG injected into the penile crura were NOS-positive. Thus, the MPG was considered to be the main source of NOS-positive nerve fibers in penile erectile tissue. PMID:7512245

  15. Hybrid fibers made of molybdenum disulfide, reduced graphene oxide, and multi-walled carbon nanotubes for solid-state, flexible, asymmetric supercapacitors.

    PubMed

    Sun, Gengzhi; Zhang, Xiao; Lin, Rongzhou; Yang, Jian; Zhang, Hua; Chen, Peng

    2015-04-01

    One of challenges existing in fiber-based supercapacitors is how to achieve high energy density without compromising their rate stability. Owing to their unique physical, electronic, and electrochemical properties, two-dimensional (2D) nanomaterials, e.g., molybdenum disulfide (MoS2 ) and graphene, have attracted increasing research interest and been utilized as electrode materials in energy-related applications. Herein, by incorporating MoS2 and reduced graphene oxide (rGO) nanosheets into a well-aligned multi-walled carbon nanotube (MWCNT) sheet followed by twisting, MoS2 -rGO/MWCNT and rGO/MWCNT fibers are fabricated, which can be used as the anode and cathode, respectively, for solid-state, flexible, asymmetric supercapacitors. This fiber-based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density. PMID:25694387

  16. Rational Design of Iron Oxide Nanoparticles as Targeted Nanomedicines for Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Kievit, Forrest M.

    2011-07-01

    Nanotechnology provides a flexible platform for the development of effective therapeutic nanomaterials that can interact specifically with a target in a biological system and provoke a desired biological response. Of the nanomaterials studied, superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as one of top candidates for cancer therapy due to their intrinsic superparamagnetism that enables non-invasive magnetic resonance imaging (MRI) and biodegradability favorable for in vivo application. This dissertation is aimed at development of SPION-based nanomedicines to overcome the current limitations in cancer therapy. These limitations include non-specificity of therapy which can harm healthy tissue, the difficulty in delivering nucleic acids for gene therapy, the formation of drug resistance, and the inability to detect and treat micrometastases. First, a SPION-based non-viral gene delivery vehicle was developed through functionalization of the SPION core with a co-polymer designed to provide stable binding of DNA and low toxicity which showed excellent gene delivery in vitro and in vivo. This SPION-based non-viral gene delivery vehicle was then activated with a targeting agent to improve gene delivery throughout a xenograft tumor of brain cancer. It was found that targeting did not promote the accumulation of SPIONs at the tumor site, but rather improved the distribution of SPIONs throughout the tumor so a higher proportion of cells received treatment. Next, the high surface area of SPIONs was utilized for loading large amounts of drug which was shown to overcome the multidrug resistance acquired by many cancer cells. Drug bound to SPIONs showed significantly higher multidrug resistant cell uptake as compared to free drug which translated into improved cell kill. Also, an antibody activated SPION was developed and was shown to be able to target micrometastases in a transgenic animal model of metastatic breast cancer. These SPION-based nanomedicines

  17. Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide.

    PubMed

    Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng

    2016-08-01

    Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples. PMID:27378648

  18. Use of Sodium Butyrate as an Alternative to Dietary Fiber: Effects on the Embryonic Development and Anti-Oxidative Capacity of Rats

    PubMed Central

    Lin, Yan; Fang, Zheng-feng; Che, Lian-qiang; Xu, Sheng-yu; Wu, De; Wu, Cai-mei; Wu, Xiu-qun

    2014-01-01

    In this study, we evaluated the effect of replacing dietary fiber with sodium butyrate on reproductive performance and antioxidant defense in a high fat diet during pregnancy by using a rat model. Eighty virgin female Sprague Dawley rats were fed one of four diets—(1) control diet (C group), (2) high fat + high fiber diet (HF group), (3) high-fat +5% sodium butyrate diet (SB group), and (4) HF diet + α-cyano-4-hydroxy cinnamic acid (CHC group)—intraperitoneally on days 8, 10, 12, 14, and 16 of gestation. SB and dietary fiber had similar effects on improving fetal number and reducing the abortion rate; however, the anti-oxidant capacity of maternal serum, placenta, and fetus was superior in the HF group than in the SB group. In comparison, CHC injection decreased reproductive performance and antioxidant defense. Both dietary fiber (DF) and SB supplementation had a major but different effect on the expression of anti-oxidant related genes and nutrient transporters genes. In summary, our data indicate that SB and DF showed similar effect on reproductive performance, but SB cannot completely replace the DF towards with respect to redox regulation in high-fat diet; and SB might influence offspring metabolism and health differently to DF. PMID:24852604

  19. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer.

    PubMed

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-03-22

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  20. The lectin-like oxidized LDL receptor-1: a new potential molecular target in colorectal cancer

    PubMed Central

    Murdocca, Michela; Mango, Ruggiero; Pucci, Sabina; Biocca, Silvia; Testa, Barbara; Capuano, Rosamaria; Paolesse, Roberto; Sanchez, Massimo; Orlandi, Augusto; di Natale, Corrado; Novelli, Giuseppe; Sangiuolo, Federica

    2016-01-01

    The identification of new biomarkers and targets for tailored therapy in human colorectal cancer (CRC) onset and progression is an interesting challenge. CRC tissue produces an excess of ox-LDL, suggesting a close correlation between lipid dysfunction and malignant transformation. Lectin-like oxidized LDL receptor-1 (LOX-1) is involved in several mechanisms closely linked to tumorigenesis. Here we report a tumor specific LOX-1 overexpression in human colon cancers: LOX-1 results strongly increased in the 72% of carcinomas (P<0.001), and strongly overexpressed in 90% of highly aggressive and metastatic tumours (P<0.001), as compared to normal mucosa. Moreover LOX-1 results modulated since the early stage of the disease (adenomas vs normal mucosa; P<0.001) suggesting an involvement in tumor insurgence and progression. The in vitro knockdown of LOX-1 in DLD-1 and HCT-8 colon cancer cells by siRNA and anti-LOX-1 antibody triggers to an impaired proliferation rate and affects the maintenance of cell growth and tumorigenicity. The wound-healing assay reveals an evident impairment in closing the scratch. Lastly knockdown of LOX-1 delineates a specific pattern of volatile compounds characterized by the presence of a butyrate derivative, suggesting a potential role of LOX-1 in tumor-specific epigenetic regulation in neoplastic cells. The role of LOX-1 as a novel biomarker and molecular target represents a concrete opportunity to improve current therapeutic strategies for CRC. In addition, the innovative application of a technology focused to the identification of LOX-1 driven volatiles specific to colorectal cancer provides a promising diagnostic tool for CRC screening and for monitoring the response to therapy. PMID:26895376

  1. Σ+p elastic scattering in the region of 300 ⩽ pΣ ⩽ 600 MeV/ c with a scintillating fiber target

    NASA Astrophysics Data System (ADS)

    Ahn, J. K.; Bassalleck, B.; Chung, M. S.; Chung, W. M.; En'yo, H.; Fukuda, T.; Funahashi, H.; Goto, Y.; Higashi, A.; Ieiri, M.; Iinuma, M.; Imai, K.; Itow, Y.; Kanda, H.; Kim, Y. D.; Lee, J. M.; Masaike, A.; Matsuda, Y.; Park, I. S.; Park, Y. M.; Saito, N.; Mihara, S.; Shin, Y. M.; Sim, K. S.; Susukita, R.; Takashima, R.; Takeutchi, F.; Tlustý, P.; Yamashita, S.; Yokkaichi, S.; Yoshida, M.; KEK-PS E251 Collaboration

    1999-03-01

    Σ+p elastic scattering has been studied using a scintillating fiber block (SCIFI) which served as a target for the production of Σ+ hyperons as well as for subsequent Σ+ scattering on hydrogen. A new technique for the analysis of the hyperon-nucleon scattering in the SCIFI has been developed and established. In this paper, Σ+p elastic scattering events have been identified in the Σ+ momentum range of 300-600 MeV/ c, and differential cross sections have been obtained at two angles. The results are compared with various theoretical baryon-baryon interaction models.

  2. Oxynitride glass fibers

    NASA Technical Reports Server (NTRS)

    Patel, Parimal J.; Messier, Donald R.; Rich, R. E.

    1991-01-01

    Research at the Army Materials Technology Laboratory (AMTL) and elsewhere has shown that many glass properties including elastic modulus, hardness, and corrosion resistance are improved markedly by the substitution of nitrogen for oxygen in the glass structure. Oxynitride glasses, therefore, offer exciting opportunities for making high modulus, high strength fibers. Processes for making oxynitride glasses and fibers of glass compositions similar to commercial oxide glasses, but with considerable enhanced properties, are discussed. We have made glasses with elastic moduli as high as 140 GPa and fibers with moduli of 120 GPa and tensile strengths up to 2900 MPa. AMTL holds a U.S. patent on oxynitride glass fibers, and this presentation discusses a unique process for drawing small diameter oxynitride glass fibers at high drawing rates. Fibers are drawn through a nozzle from molten glass in a molybdenum crucible at 1550 C. The crucible is situated in a furnace chamber in flowing nitrogen, and the fiber is wound in air outside of the chamber, making the process straightforward and commercially feasible. Strengths were considerably improved by improving glass quality to minimize internal defects. Though the fiber strengths were comparable with oxide fibers, work is currently in progress to further improve the elastic modulus and strength of fibers. The high elastic modulus of oxynitride glasses indicate their potential for making fibers with tensile strengths surpassing any oxide glass fibers, and we hope to realize that potential in the near future.

  3. Dietary fiber down-regulates colonic tumor necrosis factor alpha and nitric oxide production in trinitrobenzenesulfonic acid-induced colitic rats.

    PubMed

    Rodríguez-Cabezas, Maria Elena; Gálvez, Julio; Lorente, Maria Dolores; Concha, Angel; Camuesco, Desirée; Azzouz, Shamira; Osuna, Antonio; Redondo, Luis; Zarzuelo, Antonio

    2002-11-01

    Previous studies have revealed the beneficial effects exerted by dietary fiber in human inflammatory bowel disease, which were associated with an increased production of SCFA in distal colon. The aim of the present study was to elucidate the probable mechanisms involved in the beneficial effects of a fiber-supplemented diet (5% Plantago ovata seeds) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, with special attention to its effects on the production of some of the mediators involved in the inflammatory response, such as tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the fiber-supplemented diet for 2 wk before TNBS colitis induction and thereafter until colonic evaluation 1 wk later. The results obtained showed that dietary fiber supplementation facilitated recovery from intestinal insult as evidenced both histologically, by a preservation of intestinal cytoarchitecture, and biochemically, by a significant reduction in colonic myeloperoxidase activity and by restoration of colonic glutathione levels. This intestinal anti-inflammatory effect was associated with lower TNFalpha levels and lower NO synthase activity in the inflamed colon, showing significant differences when compared with nontreated colitic rats. Moreover, the intestinal contents from fiber-treated colitic rats showed a significantly higher production of SCFA, mainly butyrate and propionate. We conclude that the increased production of these SCFA may contribute to recovery of damaged colonic mucosa because they constitute substrates for the colonocyte and, additionally, that they can inhibit the production of proinflammatory mediators, such as TNFalpha and NO. PMID:12421838

  4. Application of hollow fiber membrane mediated with titanium dioxide nanowire/reduced graphene oxide nanocomposite in preconcentration of clotrimazole and tylosin.

    PubMed

    Sehati, Negar; Dalali, Nasser; Soltanpour, Shahla; Seyed Dorraji, Mir Saeed

    2015-11-13

    In this paper, TiO2 nanowires and TiO2 nanoparticles have been successfully anchored on graphene oxide (GO) nanosheets by a facile one-step hydrothermal method. The synthesized TiO2 NWs/RGO and TiO2 NPs/RGO nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. After comparatively studying of the as-made nanocomposites, TiO2 NWs/RGO nanocomposite showed the best adsorbing performance and applied as an attractive efficient sorbent reinforced with microporous hollow fiber membrane through the sol-gel technology. In the following, the selected nanocomposite was utilized for simultaneous preconcentration and determination of clotrimazole and tylosin using high performance liquid chromatography (HPLC)-UV detection, respectively. In order to optimize the extraction conditions through affecting parameters (pH, stirring rate, salt addition, extraction time and volume of donor phase), response surface methodology (RSM) was employed as a powerful statistical technique. Under the optimal conditions, the limit of detection (S/N=3) of proposed HFSPME method, was 0.67 μg L(-1) for clotrimazole and 0.91 μg L(-1) for tylosin with good linear ranges of 1.7-8000.0 μg L(-1) and 4.0-6000.0 μg L(-1). The inter-day and intra-day relative standard deviations (RSD%) at 100 μg L(-1) concentration level were in the ranges of 2.10-3.58% for clotrimazole and 3.45-7.80% for tylosin (n=5), respectively. The proposed microextraction device was extended for determination of ultra trace amounts of target analytes in milk and urine samples with satisfactory results. PMID:26477522

  5. Oxidative Modification of miR-184 Enables It to Target Bcl-xL and Bcl-w.

    PubMed

    Wang, Jian-Xun; Gao, Jie; Ding, Su-Ling; Wang, Kun; Jiao, Jian-Qin; Wang, Yin; Sun, Teng; Zhou, Lu-Yu; Long, Bo; Zhang, Xiao-Jie; Li, Qian; Liu, Jin-Ping; Feng, Chang; Liu, Jia; Gong, Ying; Zhou, Zhixia; Li, Pei-Feng

    2015-07-01

    MicroRNAs (miRNAs) are small non-coding RNAs, and they bind to complementary sequences in the three prime untranslated regions (3' UTRs) of target mRNA transcripts, thereby inhibiting mRNA translation or promoting mRNA degradation. Excessive reactive oxygen species (ROS) can cause cell-damaging effects through oxidative modification of macromolecules leading to their inappropriate functions. Such oxidative modification is related to cancers, aging, and neurodegenerative and cardiovascular diseases. Here we report that miRNAs can be oxidatively modified by ROS. We identified that miR-184 upon oxidative modification associates with the 3' UTRs of Bcl-xL and Bcl-w that are not its native targets. The mismatch of oxidized miR-184 with Bcl-xL and Bcl-w is involved in the initiation of apoptosis in the study with rat heart cell line H9c2 and mouse models. Our results reveal a model of ROS in regulating cellular events by oxidatively modifying miRNA. PMID:26028536

  6. Reconstruction of Colloidal Spheres by Targeted Etching: A Generalized Self-Template Route to Porous Amphoteric Metal Oxide Hollow Spheres.

    PubMed

    Pan, Jia Hong; Bai, Yuqing; Wang, Qing

    2015-04-21

    Despite the significant progress in developing various synthetic strategies for metal oxide hollow spheres (h-MO), the so-far explored materials are mostly chemically inert metal oxides. Very few attempts have been made for amphoteric metal oxides such as Al2O3 and ZnO due to the difficulties in the control of the dissolution and recrystallization process. Herein, a facile self-template route to the synthesis of amphoteric h-MO with tunable size and shell thickness is developed by targeted etching via an acid-base reaction. With the protection of polyvinylpyrrolidone (PVP) on the surface, the interior of metal oxide solid colloidal spheres (c-MOs) that possess radially divergent structures could be selectively etched with acid/alkali as an etchant, forming h-MO of Al2O3 and ZnO. Our results also show that a wide variety of metal oxide colloidal spheres can be potential self-templates for targeted etching, which paves the way for developing a generalized strategy for the synthesis of various metal oxide hollow spheres. PMID:25835084

  7. High order harmonic mode-locking in an all-normal-dispersion Yb-doped fiber laser with a graphene oxide saturable absorber

    NASA Astrophysics Data System (ADS)

    Huang, S. S.; Wang, Y. G.; Yan, P. G.; Zhang, G. L.; Zhao, J. Q.; Li, H. Q.; Lin, R. Y.

    2014-01-01

    A high order passive harmonic mode-locking (HML) Yb-doped all-normal-dispersion fiber laser based on a graphene oxide saturable absorber has been experimentally demonstrated. For two different pump powers and different polarization states of the laser cavity, lower order and higher order HML have been achieved. The highest 30th-order harmonic (31.86 MHz) was achieved with subnanosecond pulse duration; this is transitional from a bunched multipulse state.

  8. Neuronal Nitric Oxide Synthase Is Dislocated in Type I Fibers of Myalgic Muscle but Can Recover with Physical Exercise Training

    PubMed Central

    Jensen, L.; Andersen, L. L.; Schrøder, H. D.; Frandsen, U.; Sjøgaard, G.

    2015-01-01

    Trapezius myalgia is the most common type of chronic neck pain. While physical exercise reduces pain and improves muscle function, the underlying mechanisms remain unclear. Nitric oxide (NO) signaling is important in modulating cellular function, and a dysfunctional neuronal NO synthase (nNOS) may contribute to an ineffective muscle function. This study investigated nNOS expression and localization in chronically painful muscle. Forty-one women clinically diagnosed with trapezius myalgia (MYA) and 18 healthy controls (CON) were included in the case-control study. Subsequently, MYA were randomly assigned to either 10 weeks of specific strength training (SST, n = 18), general fitness training (GFT, n = 15), or health information (REF, n = 8). Distribution of fiber type, cross-sectional area, and sarcolemmal nNOS expression did not differ between MYA and CON. However, MYA showed increased sarcoplasmic nNOS localization (18.8 ± 12 versus 12.8 ± 8%, P = 0.049) compared with CON. SST resulted in a decrease of sarcoplasm-localized nNOS following training (before 18.1 ± 12 versus after 12.0 ± 12%; P = 0,027). We demonstrate that myalgic muscle displays altered nNOS localization and that 10 weeks of strength training normalize these disruptions, which supports previous findings of impaired muscle oxygenation during work tasks and reduced pain following exercise. PMID:25853139

  9. Carbon Fiber Ultramicrodic Electrode Electrodeposited with Over-Oxidized Polypyrrole for Amperometric Detection of Vesicular Exocytosis from Pheochromocytoma Cell

    PubMed Central

    Wang, Li; Xu, Huiren; Song, Yilin; Luo, Jinping; Xu, Shengwei; Zhang, Song; Liu, Juntao; Cai, Xinxia

    2015-01-01

    Vesicular exocytosis is ubiquitous, but it is difficult to detect within the cells' communication mechanism. For this purpose, a 2 μm ultramicrodic carbon fiber electrode was fabricated in this work based on electrodeposition with over-oxidized polypyrrole nanoparticle (PPyox-CFE), which was applied successfully for real-time monitoring of quantal exocytosis from individual pheochromocytoma (PC12) cells. PPyox-CFE was evaluated by dopamine (DA) solutions through cyclic voltammetry and amperometry electrochemical methods, and results revealed that PPyox-CFE improved the detection limit of DA. In particular, the sensitivity of DA was improved to 24.55 μA·μM−1·μm−2 using the PPyox-CFE. The ultramicrodic electrode combined with the patch-clamp system was used to detect vesicular exocytosis of DA from individual PC12 cells with 60 mM K+ stimulation. A total of 287 spikes released from 7 PC12 cells were statistically analyzed. The current amplitude (Imax) and the released charge (Q) of the amperometric spikes from the DA release by a stimulated PC12 cell is 45.1 ± 12.5 pA and 0.18 ± 0.04 pC, respectively. Furthermore, on average ∼562,000 molecules were released in each vesicular exocytosis. PPyox-CFE, with its capability of detecting vesicular exocytosis, has potential application in neuron communication research. PMID:25569759

  10. Optical detection of glucose and glycated hemoglobin using etched fiber Bragg gratings coated with functionalized reduced graphene oxide.

    PubMed

    Sridevi, S; Vasu, K S; Sampath, S; Asokan, S; Sood, A K

    2016-07-01

    An enhanced optical detection of D-glucose and glycated hemoglobin (HbA1c ) has been established in this study using etched fiber Bragg gratings (eFBG) coated with aminophenylboronic acid (APBA)-functionalized reduced graphene oxide (RGO). The read out, namely the shift in Bragg wavelength (ΔλB ) is highly sensitive to changes that occur due to the adsorption of glucose (or HbA1c ) molecules on the eFBG sensor coated with APBA-RGO complex through a five-membered cyclic ester bond formation between glucose and APBA molecules. A limit of detection of 1 nM is achieved with a linear range of detection from 1 nM to 10 mM in the case of D-glucose detection experiments. For HbA1c , a linear range of detection varying from 86 nM to 0.23 mM is achieved. The observation of only 4 pm (picometer) change in ΔλB even for the 10 mM lactose solution confirms the specificity of the APBA-RGO complex coated eFBG sensors to glucose molecules. PMID:26266873

  11. Nitric oxide pretreatment enhances atheroma component highlighting in vivo with intercellular adhesion molecule-1-targeted echogenic liposomes.

    PubMed

    Kee, Patrick H; Kim, Hyunggun; Huang, Shaoling; Laing, Susan T; Moody, Melanie R; Vela, Deborah; Klegerman, Melvin E; McPherson, David D

    2014-06-01

    We present an ultrasound technique for the detection of inflammatory changes in developing atheromas. We used contrast-enhanced ultrasound imaging with (i) microbubbles targeted to intercellular adhesion molecule-1 (ICAM-1), a molecule of adhesion involved in inflammatory processes in lesions of atheromas in New Zealand White rabbits, and (ii) pretreatment with nitric oxide-loaded microbubbles and ultrasound activation at the site of the endothelium to enhance the permeability of the arterial wall and the penetration of ICAM-1-targeted microbubbles. This procedure increases acoustic enhancement 1.2-fold. Pretreatment with nitric oxide-loaded echogenic liposomes and ultrasound activation can potentially facilitate the subsequent penetration of targeted echogenic liposomes into the arterial wall, thus allowing improved detection of inflammatory changes in developing atheromas. PMID:24613216

  12. Glioma-targeted superparamagnetic iron oxide nanoparticles as drug-carrying vehicles for theranostic effects.

    PubMed

    Xu, He-Lin; Mao, Kai-Li; Huang, Yin-Ping; Yang, Jing-Jing; Xu, Jie; Chen, Pian-Pian; Fan, Zi-Liang; Zou, Shuang; Gao, Zheng-Zheng; Yin, Jia-Yu; Xiao, Jian; Lu, Cui-Tao; Zhang, Bao-Lin; Zhao, Ying-Zheng

    2016-08-01

    Multifunctional nanoparticles capable of the specific delivery of therapeutics to diseased cells and the real-time imaging of these sites have the potential to improve cancer treatment through personalized therapy. In this study, we have proposed a multifunctional nanoparticle that integrate magnetic targeting, drug-carrier functionality and real-time MRI imaging capabilities in one platform for the theranostic treatment of tumors. The multifunctional nanoparticle was designed with a superparamagnetic iron oxide core and a multifunctional shell composed of PEG/PEI/polysorbate 80 (Ps 80) and was used to encapsulate DOX. DOX-loaded multifunctional nanoparticles (DOX@Ps 80-SPIONs) with a Dh of 58.0 nm, a zeta potential of 28.0 mV, and a drug loading content of 29.3% presented superior superparamagnetic properties with a saturation magnetization (Ms) of 24.1 emu g(-1). The cellular uptake of DOX@Ps 80-SPIONs by C6 cells under a magnetic field was significantly enhanced over that of free DOX in solution, resulting in stronger in vitro cytotoxicity. The real-time therapeutic outcome of DOX@Ps 80-SPIONs was easily monitored by MRI. Furthermore, the negative contrast enhancement effect of the nanoparticles was confirmed in glioma-bearing rats. Prussian blue staining and ex vivo DOX fluorescence assays showed that the magnetic Ps 80-SPIONs and encapsulated DOX were delivered to gliomas by imposing external magnetic fields, indicating effective magnetic targeting. Due to magnetic targeting and Ps 80-mediated endocytosis, DOX@Ps 80-SPIONs in the presence of a magnetic field led to the complete suppression of glioma growth in vivo at 28 days after treatment. The therapeutic mechanism of DOX@Ps 80-SPIONs acted by inducing apoptosis through the caspase-3 pathway. Finally, DOX@Ps 80-SPIONs' safety at therapeutic dosage was verified using pathological HE assays of the heart, liver, spleen, lung and kidney. Multifunctional SPIONs could be used as potential carriers for the

  13. MiR-590-5p Inhibits Oxidized- LDL Induced Angiogenesis by Targeting LOX-1

    PubMed Central

    Dai, Yao; Zhang, Zhigao; Cao, Yongxiang; Mehta, Jawahar L.; Li, Jun

    2016-01-01

    Oxidized low-density lipoprotein (ox-LDL) is, at least in part, responsible for angiogenesis in atherosclerotic regions. This effect of ox-LDL has been shown to be mediated through a specific receptor LOX-1. Here we describe the effect of miR-590-5p on ox-LDL-mediated angiogenesis in in vitro and in vivo settings. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-590-5p mimic or inhibitor followed by treatment with ox-LDL. In other experiments, Marigel plugs were inserted in the mice subcutaneous space. Both in vitro and in vivo studies showed that miR-590-5p mimic (100 nM) inhibited the ox-LDL-mediated angiogenesis (capillary tube formation, cell proliferation and migration as well as pro-angiogenic signals- ROS, MAPKs, pro-inflammatory cytokines and adhesion-related proteins). Of note, miR-590-5p inhibitor (200 nM) had the opposite effects. The inhibitory effect of miR-590-5p on angiogenesis was mediated by inhibition of LOX-1 at translational level. The inhibition of LOX-1 by miR-590-5p was confirmed by luciferase assay. In conclusion, we show that MiR-590-5p inhibits angiogenesis by targeting LOX-1 and suppressing redox-sensitive signals. PMID:26932825

  14. MiR-590-5p Inhibits Oxidized- LDL Induced Angiogenesis by Targeting LOX-1.

    PubMed

    Dai, Yao; Zhang, Zhigao; Cao, Yongxiang; Mehta, Jawahar L; Li, Jun

    2016-01-01

    Oxidized low-density lipoprotein (ox-LDL) is, at least in part, responsible for angiogenesis in atherosclerotic regions. This effect of ox-LDL has been shown to be mediated through a specific receptor LOX-1. Here we describe the effect of miR-590-5p on ox-LDL-mediated angiogenesis in in vitro and in vivo settings. Human umbilical vein endothelial cells (HUVECs) were transfected with miR-590-5p mimic or inhibitor followed by treatment with ox-LDL. In other experiments, Marigel plugs were inserted in the mice subcutaneous space. Both in vitro and in vivo studies showed that miR-590-5p mimic (100 nM) inhibited the ox-LDL-mediated angiogenesis (capillary tube formation, cell proliferation and migration as well as pro-angiogenic signals- ROS, MAPKs, pro-inflammatory cytokines and adhesion-related proteins). Of note, miR-590-5p inhibitor (200 nM) had the opposite effects. The inhibitory effect of miR-590-5p on angiogenesis was mediated by inhibition of LOX-1 at translational level. The inhibition of LOX-1 by miR-590-5p was confirmed by luciferase assay. In conclusion, we show that MiR-590-5p inhibits angiogenesis by targeting LOX-1 and suppressing redox-sensitive signals. PMID:26932825

  15. Female resistance to pneumonia identifies lung macrophage nitric oxide synthase-3 as a therapeutic target

    PubMed Central

    Yang, Zhiping; Huang, Yuh-Chin T; Koziel, Henry; de Crom, Rini; Ruetten, Hartmut; Wohlfart, Paulus; Thomsen, Reimar W; Kahlert, Johnny A; Sørensen, Henrik Toft; Jozefowski, Szczepan; Colby, Amy; Kobzik, Lester

    2014-01-01

    To identify new approaches to enhance innate immunity to bacterial pneumonia, we investigated the natural experiment of gender differences in resistance to infections. Female and estrogen-treated male mice show greater resistance to pneumococcal pneumonia, seen as greater bacterial clearance, diminished lung inflammation, and better survival. In vitro, lung macrophages from female mice and humans show better killing of ingested bacteria. Inhibitors and genetically altered mice identify a critical role for estrogen-mediated activation of lung macrophage nitric oxide synthase-3 (NOS3). Epidemiologic data show decreased hospitalization for pneumonia in women receiving estrogen or statins (known to activate NOS3). Pharmacologic targeting of NOS3 with statins or another small-molecule compound (AVE3085) enhanced macrophage bacterial killing, improved bacterial clearance, and increased host survival in both primary and secondary (post-influenza) pneumonia. The data identify a novel mechanism for host defense via NOS3 and suggest a potential therapeutic strategy to reduce secondary bacterial pneumonia after influenza. DOI: http://dx.doi.org/10.7554/eLife.03711.001 PMID:25317947

  16. A versatile fluorescent biosensor based on target-responsive graphene oxide hydrogel for antibiotic detection.

    PubMed

    Tan, Bing; Zhao, Huimin; Du, Lei; Gan, Xiaorong; Quan, Xie

    2016-09-15

    A fluorescent sensing platform based on graphene oxide (GO) hydrogel was developed through a fast and facile gelation, immersion and fluorescence determination process, in which the adenosine and aptamer worked as the co-crosslinkers to connect the GO sheets and then form the three-dimensional (3D) macrostructures. The as-prepared hydrogel showed high mechanical strength and thermal stability. The optimal hydrogel had a linear response for oxytetracycline (OTC) of 25-1000μg/L and a limit of quantitation (LOQ) of 25μg/L. Moreover, together with the high affinity of the aptamer for its target, this assay exhibited excellent sensitivity and selectivity. According to its design principle, the as-designed hydrogel was also tested to possess the generic detection function for other molecules by simply replacing its recognition element, which is expected to lay a foundation to realize the assembly of functionalized hierarchical graphene-based materials for practical applications in analytical field. PMID:27132000

  17. Silicon oxide cluster formation and stability in the laser ablation of SiO targets.

    PubMed

    Jadraque, María; Santos, Magna; Díaz, Luís; Alvarez-Ruiz, Jesús; Martín, Margarita

    2009-10-15

    The formation mechanism and stability of silicon oxide clusters observed in the ablation of SiO targets at 266 nm were investigated by time-of-flight mass spectrometry, laser-induced fluorescence (LIF), and DFT calculations. Neutral and positively charged Si(n)(+/0) and Si(n)O(m)H(0,1)(+) clusters were identified in the plume, but neutral Si(n)O(m) could not be observed. The time distribution of SiO in the plume measured by postionization with an ArF laser (Delta lambda approximately 1 nm, tau approximately 14 ns) and mass spectrometric detection was compared with that obtained by LIF with narrowband dye laser selective excitation of one specific rovibronic transition in SiO. Postionization leads to a multicomponent distribution that extends up to times near 100 micros after ablation, whereas LIF measurements obtain time distributions shorter than 20 micros. DFT calculations of several Si(n)O(m)(0/+) were performed, showing that one photon absorption of the postionization laser makes available low-energy dissociation channels of the neutrals, whereas two photon absorption is required for ionization. DFT calculations were carried out for stoichiometric H-containing clusters Si(n)O(n)H(+) (n = 1-4). For n = 1,2, the optimized geometries involve bonding of hydrogen to one oxygen atom in the clusters; for n = 3 and 4, the structures containing H-Si bonds are more stable. PMID:19810756

  18. Facile synthesis of manganese ferrite/graphene oxide nanocomposites for controlled targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Wang, Guangshuo; Ma, Yingying; Zhang, Lina; Mu, Jingbo; Zhang, Zhixiao; Zhang, Xiaoliang; Che, Hongwei; Bai, Yongmei; Hou, Junxian

    2016-03-01

    In this study, manganese ferrite/graphene oxide (MnFe2O4/GO) nanocomposites as controlled targeted drug delivery were prepared by a facile sonochemical method. It was found that GO nanosheets were fully exfoliated and decorated with MnFe2O4 nanoparticles having diameters of 5-13 nm. The field-dependent magnetization curve indicated superparamagnetic behavior of the obtained MnFe2O4/GO with saturation magnetization of 34.9 emu/g at room temperature. The in vitro cytotoxicity testing exhibited negligible cytotoxicity of as-prepared MnFe2O4/GO even at the concentration as high as 150 μg/mL. Doxorubicin hydrochloride (DOX) as an anti-tumor model drug was utilized to explore the application potential of MnFe2O4/GO for controlled drug delivery. The drug loading capacity of this nanocarrier was as high as 0.97 mg/mg and the drug release behavior showed a sustained and pH-responsive way.

  19. Review of transcranial photobiomodulation for major depressive disorder: targeting brain metabolism, inflammation, oxidative stress, and neurogenesis.

    PubMed

    Cassano, Paolo; Petrie, Samuel R; Hamblin, Michael R; Henderson, Theodore A; Iosifescu, Dan V

    2016-07-01

    We examined the use of near-infrared and red radiation (photobiomodulation, PBM) for treating major depressive disorder (MDD). While still experimental, preliminary data on the use of PBM for brain disorders are promising. PBM is low-cost with potential for wide dissemination; further research on PBM is sorely needed. We found clinical and preclinical studies via PubMed search (2015), using the following keywords: "near-infrared radiation," "NIR," "low-level light therapy," "low-level laser therapy," or "LLLT" plus "depression." We chose clinically focused studies and excluded studies involving near-infrared spectroscopy. In addition, we used PubMed to find articles that examine the link between PBM and relevant biological processes including metabolism, inflammation, oxidative stress, and neurogenesis. Studies suggest the processes aforementioned are potentially effective targets for PBM to treat depression. There is also clinical preliminary evidence suggesting the efficacy of PBM in treating MDD, and comorbid anxiety disorders, suicidal ideation, and traumatic brain injury. Based on the data collected to date, PBM appears to be a promising treatment for depression that is safe and well-tolerated. However, large randomized controlled trials are still needed to establish the safety and effectiveness of this new treatment for MDD. PMID:26989758

  20. Polymer encapsulated upconversion nanoparticle/iron oxide nanocomposites for multimodal imaging and magnetic targeted drug delivery.

    PubMed

    Xu, Huan; Cheng, Liang; Wang, Chao; Ma, Xinxing; Li, Yonggang; Liu, Zhuang

    2011-12-01

    Multimodal imaging and imaging-guided therapies have become a new trend in the current development of cancer theranostics. In this work, we encapsulate hydrophobic upconversion nanoparticles (UCNPs) together with iron oxide nanoparticles (IONPs) by using an amphiphilic block copolymer, poly (styrene-block-allyl alcohol) (PS(16)-b-PAA(10)), via a microemulsion method, obtaining an UC-IO@Polymer multi-functional nanocomposite system. Fluorescent dye and anti-cancer drug molecules can be further loaded inside the UC-IO@Polymer nanocomposite for additional functionalities. Utilizing the Squaraine (SQ) dye loaded nanocomposite (UC-IO@Polymer-SQ), triple-modal upconversion luminescence (UCL)/down-conversion fluorescence (FL)/magnetic resonance (MR) imaging is demonstrated in vitro and in vivo, and also applied for in vivo cancer cell tracking in mice. On the other hand, a chemotherapy drug, doxorubicin, is also loaded into the nanocomposite, forming an UC-IO@Polymer-DOX complex, which enables novel imaging-guided and magnetic targeted drug delivery. Our work provides a method to fabricate a nanocomposite system with highly integrated functionalities for multimodal biomedical imaging and cancer therapy. PMID:21880364

  1. Magnetic Resonance Imaging of Atherosclerosis Using CD81-Targeted Microparticles of Iron Oxide in Mice

    PubMed Central

    Yan, Fei; Yang, Wei; Li, Xiang; Liu, Hongmei; Nan, Xiang; Xie, Lisi; Zhou, Dongliang; Xie, Guoxi; Wu, Junru; Qiu, Bensheng; Liu, Xin; Zheng, Hairong

    2015-01-01

    The goal of this study is to investigate the feasibility of using CD81- (Cluster of Differentiation 81 protein-) targeted microparticles of iron oxide (CD81-MPIO) for magnetic resonance imaging (MRI) of the murine atherosclerosis. CD81-MPIO and IgG- (Immunoglobulin G-) MPIO were prepared by covalently conjugating, respectively, with anti-CD81 monoclonal and IgG antibodies to the surface of the tosyl activated MPIO. The relevant binding capability of the MPIO was examined by incubating them with murine bEnd.3 cells stimulated with phenazine methosulfate (PMS) and its effect in shortening T2 relaxation time was also examined. MRI in apolipoprotein E-deficient mice was studied in vivo. Our results show that CD81-MPIO, but not IgG-MPIO, can bind to the PMS-stimulated bEnd.3 cells. The T2 relaxation time was significantly shortened for stimulated bEnd.3 cells when compared with IgG-MPIO. In vivo MRI in apolipoprotein E-deficient mice showed highly conspicuous areas of low signal after CD81-MPIO injection. Quantitative analysis of the area of CD81-MPIO contrast effects showed 8.96- and 6.98-fold increase in comparison with IgG-MPIO or plain MPIO, respectively (P < 0.01). Histological assay confirmed the expression of CD81 and CD81-MPIO binding onto atherosclerotic lesions. In conclusion, CD81-MPIO allows molecular assessment of murine atherosclerotic lesions by magnetic resonance imaging. PMID:26266263

  2. Application of a solid-phase microextraction fiber coated with a graphene oxide-poly(dimethylsiloxane) composite for the extraction of triazoles from water.

    PubMed

    Li, Zhi; Ma, Ruiyang; Zhang, Guijiang; Zhang, Shuaihua; Wang, Chun; Wu, Qiuhua; Wang, Zhi

    2016-08-01

    A solid-phase microextraction fiber was prepared by mixing graphene oxide and hydroxyl-terminated polydimethylsiloxane together and then coating the mixture on the surface of etched stainless-steel wire by sol-gel technology. After aging by heating, the graphene oxide-polydimethylsiloxane composite coated fiber was used for the direct solid phase microextraction of triazole fungicides from water samples. The properties of the graphene oxide-polydimethylsiloxane coating were characterized by transmission electron microscopy and thermogravimetric analysis. And the chemical stability of the coating was tested as well. Several important experimental parameters that could influence the extraction efficiency such as desorption temperature and time, extraction temperature and time, sample pH and stirring rate, were investigated and optimized. Under the optimized conditions, the limits of detection were in the range from 0.01 to 0.03 μg/L. The results indicated that the homemade fiber had the advantages of good thermal and chemical stability and high extraction efficiency, which was successfully applied to the analysis of triazoles in water samples. PMID:27306964

  3. SFRR-E Young Investigator AwardeeαB-crystallin modulation after acute exercise in skeletal muscle: the role of oxidative stress and fiber composition.

    PubMed

    Grazioli, Elisa; Dimauro, Ivan; Mercatelli, Neri; Barone, Rosario; Macaluso, Filippo; Fittipaldi, Simona; Di Felice, Valentina; Caporossi, Daniela

    2014-10-01

    αB-crystallin (CRYAB) is a member of the small heat shock proteins implicated in various biological functions, particularly in skeletal muscle where it is involved in adaptive remodelling processes, activation of gene transcription and stabilization of nascent proteins.In this research we analysed αB-crystallin' response in mouse gastrocnemius at 15' and 30' of recovery from an acute aerobic exercise (1hour), correlating its modulation with oxidative stress level and fiber composition, red (RG) and white gastrocnemius (WG).We found for the first time that the acute exercise lead to a short term, specific increase of phospho-αB-crystallin level (pCRYAB) in the RG, while no changes were observed in the WG. Moreover, this induction was correlated with increased level of 4-hydroxynonenal (HNE),suggesting a putative role for oxidative stress in driving CRYAB, but not hsp70 or hsp27, activity during exercise. Any increased level of αB-crystallin' protein was observed neither in RG nor in WG. These data were also supported by our in vitro experiments showing a significant enhancement of pCRYAB in H2O2-treated C2C12 myotubes.Although our results seem suggest a fiber-dependent role of CRYAB, further experiments are in progress to clarify both the molecular pathway driving CRYAB phosphorylation and its fiber-specific induction after exercise -induced oxidative stress.This work was supported by MIUR - PRIN 2012 grant. PMID:26461288

  4. Graphitized-carbon fiber/carbon char fuel

    SciTech Connect

    Cooper, John F.

    2007-08-28

    A method for recovery of intact graphitic fibers from fiber/polymer composites is described. The method comprises first pyrolyzing the graphite fiber/polymer composite mixture and then separating the graphite fibers by molten salt electrochemical oxidation.

  5. Glioma-targeted superparamagnetic iron oxide nanoparticles as drug-carrying vehicles for theranostic effects

    NASA Astrophysics Data System (ADS)

    Xu, He-Lin; Mao, Kai-Li; Huang, Yin-Ping; Yang, Jing-Jing; Xu, Jie; Chen, Pian-Pian; Fan, Zi-Liang; Zou, Shuang; Gao, Zheng-Zheng; Yin, Jia-Yu; Xiao, Jian; Lu, Cui-Tao; Zhang, Bao-Lin; Zhao, Ying-Zheng

    2016-07-01

    Multifunctional nanoparticles capable of the specific delivery of therapeutics to diseased cells and the real-time imaging of these sites have the potential to improve cancer treatment through personalized therapy. In this study, we have proposed a multifunctional nanoparticle that integrate magnetic targeting, drug-carrier functionality and real-time MRI imaging capabilities in one platform for the theranostic treatment of tumors. The multifunctional nanoparticle was designed with a superparamagnetic iron oxide core and a multifunctional shell composed of PEG/PEI/polysorbate 80 (Ps 80) and was used to encapsulate DOX. DOX-loaded multifunctional nanoparticles (DOX@Ps 80-SPIONs) with a Dh of 58.0 nm, a zeta potential of 28.0 mV, and a drug loading content of 29.3% presented superior superparamagnetic properties with a saturation magnetization (Ms) of 24.1 emu g-1. The cellular uptake of DOX@Ps 80-SPIONs by C6 cells under a magnetic field was significantly enhanced over that of free DOX in solution, resulting in stronger in vitro cytotoxicity. The real-time therapeutic outcome of DOX@Ps 80-SPIONs was easily monitored by MRI. Furthermore, the negative contrast enhancement effect of the nanoparticles was confirmed in glioma-bearing rats. Prussian blue staining and ex vivo DOX fluorescence assays showed that the magnetic Ps 80-SPIONs and encapsulated DOX were delivered to gliomas by imposing external magnetic fields, indicating effective magnetic targeting. Due to magnetic targeting and Ps 80-mediated endocytosis, DOX@Ps 80-SPIONs in the presence of a magnetic field led to the complete suppression of glioma growth in vivo at 28 days after treatment. The therapeutic mechanism of DOX@Ps 80-SPIONs acted by inducing apoptosis through the caspase-3 pathway. Finally, DOX@Ps 80-SPIONs' safety at therapeutic dosage was verified using pathological HE assays of the heart, liver, spleen, lung and kidney. Multifunctional SPIONs could be used as potential carriers for the

  6. Glioma-targeted superparamagnetic iron oxide nanoparticles as drug-carrying vehicles for theranostic effects

    NASA Astrophysics Data System (ADS)

    Xu, He-Lin; Mao, Kai-Li; Huang, Yin-Ping; Yang, Jing-Jing; Xu, Jie; Chen, Pian-Pian; Fan, Zi-Liang; Zou, Shuang; Gao, Zheng-Zheng; Yin, Jia-Yu; Xiao, Jian; Lu, Cui-Tao; Zhang, Bao-Lin; Zhao, Ying-Zheng

    2016-07-01

    Multifunctional nanoparticles capable of the specific delivery of therapeutics to diseased cells and the real-time imaging of these sites have the potential to improve cancer treatment through personalized therapy. In this study, we have proposed a multifunctional nanoparticle that integrate magnetic targeting, drug-carrier functionality and real-time MRI imaging capabilities in one platform for the theranostic treatment of tumors. The multifunctional nanoparticle was designed with a superparamagnetic iron oxide core and a multifunctional shell composed of PEG/PEI/polysorbate 80 (Ps 80) and was used to encapsulate DOX. DOX-loaded multifunctional nanoparticles (DOX@Ps 80-SPIONs) with a Dh of 58.0 nm, a zeta potential of 28.0 mV, and a drug loading content of 29.3% presented superior superparamagnetic properties with a saturation magnetization (Ms) of 24.1 emu g-1. The cellular uptake of DOX@Ps 80-SPIONs by C6 cells under a magnetic field was significantly enhanced over that of free DOX in solution, resulting in stronger in vitro cytotoxicity. The real-time therapeutic outcome of DOX@Ps 80-SPIONs was easily monitored by MRI. Furthermore, the negative contrast enhancement effect of the nanoparticles was confirmed in glioma-bearing rats. Prussian blue staining and ex vivo DOX fluorescence assays showed that the magnetic Ps 80-SPIONs and encapsulated DOX were delivered to gliomas by imposing external magnetic fields, indicating effective magnetic targeting. Due to magnetic targeting and Ps 80-mediated endocytosis, DOX@Ps 80-SPIONs in the presence of a magnetic field led to the complete suppression of glioma growth in vivo at 28 days after treatment. The therapeutic mechanism of DOX@Ps 80-SPIONs acted by inducing apoptosis through the caspase-3 pathway. Finally, DOX@Ps 80-SPIONs' safety at therapeutic dosage was verified using pathological HE assays of the heart, liver, spleen, lung and kidney. Multifunctional SPIONs could be used as potential carriers for the

  7. Roles of inorganic oxide nanoparticles on extraction efficiency of electrospun polyethylene terephthalate nanocomposite as an unbreakable fiber coating.

    PubMed

    Bagheri, Habib; Roostaie, Ali

    2015-01-01

    In the present work, the roles of inorganic oxide nanoparticles on the extraction efficiency of polyethylene terephthalate-based nanocomposites were extensively studied. Four fiber coatings based on polyethylene terephthalate nanocomposites containing different types of nanoparticles along with a pristine polyethylene terephthalate polymer were conveniently electrospun on stainless steel wires. The applicability of new fiber coatings were examined by headspace-solid phase microextraction of some environmentally important volatile organic compound such as benzene, toluene, ethylbenzene and xylene (BTEX), as model compounds, from aqueous samples. Subsequently, the extracted analytes were transferred into a gas chromatography by thermal desorption. Parameters affecting the morphology and capability of the prepared nanocomposites including the type of nanoparticles and their doping levels along with the coating time were optimized. Four types of nanoparticles including Fe3O4, SiO2, CoO and NiO were examined as the doping agents and among them the presence of SiO2 in the prepared nanocomposite was prominent. The homogeneity and the porous surface structure of the SiO2-polyethylene terephthalate nanocomposite were confirmed by scanning electron microscopy indicating that the nanofibers diameters were lower than 300 nm. In addition, important parameters influencing the extraction and desorption process such as temperature and extraction time, ionic strength and desorption conditions were optimized. Eventually, the developed method was validated by gas chromatography-mass spectrometry. Under optimized conditions, the relative standard deviation values for a double distilled water spiked with the selected volatile organic compounds at 50 ng L(-1) were 2-7% (n=3) while the limits of detection were between 0.7 and 0.9 ng L(-1). The method was linear in the concentration range of 10 to 1,000 ng L(-1) (R(2)>0.9992). Finally, the developed method was applied to the analysis of

  8. Ion-enhanced oxidation of aluminum as a fundamental surface process during target poisoning in reactive magnetron sputtering

    SciTech Connect

    Kuschel, Thomas; Keudell, Achim von

    2010-05-15

    Plasma deposition of aluminum oxide by reactive magnetron sputtering (RMS) using an aluminum target and argon and oxygen as working gases is an important technological process. The undesired oxidation of the target itself, however, causes the so-called target poisoning, which leads to strong hysteresis effects during RMS operation. The oxidation occurs by chemisorption of oxygen atoms and molecules with a simultaneous ion bombardment being present. This heterogenous surface reaction is studied in a quantified particle beam experiment employing beams of oxygen molecules and argon ions impinging onto an aluminum-coated quartz microbalance. The oxidation and/or sputtering rates are measured with this microbalance and the resulting oxide layers are analyzed by x-ray photoelectron spectroscopy. The sticking coefficient of oxygen molecules is determined to 0.015 in the zero coverage limit. The sputtering yields of pure aluminum by argon ions are determined to 0.4, 0.62, and 0.8 at 200, 300, and 400 eV. The variation in the effective sticking coefficient and sputtering yield during the combined impact of argon ions and oxygen molecules is modeled with a set of rate equations. A good agreement is achieved if one postulates an ion-induced surface activation process, which facilitates oxygen chemisorption. This process may be identified with knock-on implantation of surface-bonded oxygen, with an electric-field-driven in-diffusion of oxygen or with an ion-enhanced surface activation process. Based on these fundamental processes, a robust set of balance equations is proposed to describe target poisoning effects in RMS.

  9. Diversity-Oriented Synthesis Probe Targets Plasmodium falciparum Cytochrome b Ubiquinone Reduction Site and Synergizes With Oxidation Site Inhibitors

    PubMed Central

    Lukens, Amanda K.; Heidebrecht, Richard W.; Mulrooney, Carol; Beaudoin, Jennifer A.; Comer, Eamon; Duvall, Jeremy R.; Fitzgerald, Mark E.; Masi, Daniela; Galinsky, Kevin; Scherer, Christina A.; Palmer, Michelle; Munoz, Benito; Foley, Michael; Schreiber, Stuart L.; Wiegand, Roger C.; Wirth, Dyann F.

    2015-01-01

    Background. The emergence and spread of drug resistance to current antimalarial therapies remains a pressing concern, escalating the need for compounds that demonstrate novel modes of action. Diversity-Oriented Synthesis (DOS) libraries bridge the gap between conventional small molecule and natural product libraries, allowing the interrogation of more diverse chemical space in efforts to identify probes of novel parasite pathways. Methods. We screened and optimized a probe from a DOS library using whole-cell phenotypic assays. Resistance selection and whole-genome sequencing approaches were employed to identify the cellular target of the compounds. Results. We identified a novel macrocyclic inhibitor of Plasmodium falciparum with nanomolar potency and identified the reduction site of cytochrome b as its cellular target. Combination experiments with reduction and oxidation site inhibitors showed synergistic inhibition of the parasite. Conclusions. The cytochrome b oxidation center is a validated antimalarial target. We show that the reduction site of cytochrome b is also a druggable target. Our results demonstrating a synergistic relationship between oxidation and reduction site inhibitors suggests a future strategy for new combination therapies in the treatment of malaria. PMID:25336726

  10. Skeletal muscle lipid content and oxidative activity in relation to muscle fiber type in aging and metabolic syndrome.

    PubMed

    Gueugneau, Marine; Coudy-Gandilhon, Cécile; Théron, Laëtitia; Meunier, Bruno; Barboiron, Christiane; Combaret, Lydie; Taillandier, Daniel; Polge, Cécile; Attaix, Didier; Picard, Brigitte; Verney, Julien; Roche, Frédéric; Féasson, Léonard; Barthélémy, Jean-Claude; Béchet, Daniel

    2015-05-01

    One of the most noticeable effects of aging is the reduction in skeletal muscle mass and strength (sarcopenia). The metabolic syndrome (MS) is also prevalent in old subjects, but its relevance to skeletal muscle characteristics has poorly been investigated. Immunohistochemical studies were performed with muscle biopsies from young (22 years) and old (73 years) men with and without MS to reveal age-dependent and MS-associated modifications of fiber-type characteristics. Atrophy of type II fibers and altered fiber shape characterized muscle aging in lean healthy men. In contrast, increased cross-sectional area of the most abundant type I and type IIA fibers, and reduced cytochrome c oxidase content in all fiber types, characterized MS. Aging and particularly MS were associated with accumulation of intramyocellular lipid droplets. Although lipids mostly accumulated in type I fibers, matrix-assisted laser desorption/ionization-mass spectrometry imaging of intramyocellular lipids did not distinguish fiber types, but clearly separated young, old, and MS subjects. In conclusion, our study suggests that MS in the elderly persons is associated with alterations in skeletal muscle at a fiber-type specific level. Overall, these fiber type-specific modifications may be important both for the age-related loss of muscle mass and strength and for the increased prevalence of MS in elderly subjects. PMID:24939997

  11. miR-214 protects erythroid cells against oxidative stress by targeting ATF4 and EZH2.

    PubMed

    Gao, Ming; Liu, Yun; Chen, Yue; Yin, Chunyang; Chen, Jane-Jane; Liu, Sijin

    2016-03-01

    Nuclear factor (erythroid-derived 2) like 2 (Nrf2) is a key regulator in protecting cells against stress by targeting many anti-stress response genes. Recent evidence also reveals that Nrf2 functions partially by targeting mircroRNAs (miRNAs). However, the understanding of Nrf2-mediated cytoprotection through miRNA-dependent mechanisms is largely unknown. In the current study, we identified a direct Nrf2 targeting miRNA, miR-214, and demonstrated a protective role of miR-214 in erythroid cells against oxidative stresses generated by radiation, excess iron and arsenic (As) exposure. miR-214 expression was transcriptionally repressed by Nrf2 through a canonical antioxidant response element (ARE) within its promoter region, and this repression is ROS-dependence. The suppression of miR-214 by Nrf2 could antagonize oxidative stress-induced cell death in erythroid cells by two ways. First, miR-214 directly targeted ATF4, a crucial transcriptional factor involved in anti-stress responses, down regulation of miR-214 releases the repression of ATF4 translation and leads to increased ATF4 protein content. Second, miR-214 was able to prevent cell death by targeting EZH2, the catalytic core component of PRC2 complex that is responsible for tri-methylation reaction at lysine 27 (K27) of histone 3 (H3) (H3K27me3), by which As-induced miR-214 reduction resulted in an increased global H3K27me3 level and a compromised overexpression of a pro-apoptotic gene Bim. These two pathways downstream of miR-214 synergistically cooperated to antagonize erythroid cell death upon oxidative stress. Our combined data revealed a protective role of miR-214 signaling in erythroid cells against oxidative stress, and also shed new light on Nrf2-mediated cytoprotective machinery. PMID:26791102

  12. The synergistic effect of folate and RGD dual ligand of nanographene oxide on tumor targeting and photothermal therapy in vivo

    NASA Astrophysics Data System (ADS)

    Jang, Cheol; Lee, Jong Hyun; Sahu, Abhishek; Tae, Giyoong

    2015-11-01

    Effective delivery of nanoparticles to the target site is necessary for successful biomedical applications. Inefficient targeting is a major concern for nanomedicines in cancer therapy. Conjugation of multiple targeting ligands to the nanoparticle surface might further enhance the targeting efficiency by a co-operative effect of individual ligands. In this study, a dual ligand targeting nanographene oxide (nGO) was developed by non-covalent interaction with folate and cRGD functionalized pluronic, which allowed precise control of ligand number on the nGO surface and ensured stability under physiological conditions. The tumor targeting abilities of single and dual ligand decorated nGOs were evaluated in vitro by using KB cells, over-expressing folate and integrin αvβ3 receptors. In vitro cellular uptake analysis by flow cytometry and confocal laser scanning microscopy showed enhanced uptake of dual ligand modified nGO compared to any of the single ligand modified nGOs. The cellular uptake of dual targeted cRGD-FA-nGO was increased by 1.9 and 2.4 folds compared to single targeted cRGD-nGO or FA-nGO, respectively. The in vivo biodistribution experiment in a mouse xenograft model also confirmed the synergistic targeting effect of cRGD and folate dual functionalized nGO. A significantly higher tumor accumulation of cRGD-FA-nGO was observed compared to cRGD-nGO or FA-nGO. The higher tumor accumulation of dual targeted nGO resulted in complete ablation of tumor tissue through an enhanced photothermal effect by NIR laser irradiation. Therefore, co-functionalization of a nanoparticle by cRGD and folate is a potentially useful way to enhance the tumor targeting efficacy.Effective delivery of nanoparticles to the target site is necessary for successful biomedical applications. Inefficient targeting is a major concern for nanomedicines in cancer therapy. Conjugation of multiple targeting ligands to the nanoparticle surface might further enhance the targeting efficiency by a

  13. In Vivo Molecular MRI Imaging of Prostate Cancer by Targeting PSMA with Polypeptide-Labeled Superparamagnetic Iron Oxide Nanoparticles

    PubMed Central

    Zhu, Yunkai; Sun, Ying; Chen, Yaqing; Liu, Weiyong; Jiang, Jun; Guan, Wenbin; Zhang, Zhongyang; Duan, Yourong

    2015-01-01

    The prostate specific membrane antigen (PSMA) is broadly overexpressed on prostate cancer (PCa) cell surfaces. In this study, we report the synthesis, characterization, in vitro binding assay, and in vivo magnetic resonance imaging (MRI) evaluation of PSMA targeting superparamagnetic iron oxide nanoparticles (SPIONs). PSMA-targeting polypeptide CQKHHNYLC was conjugated to SPIONs to form PSMA-targeting molecular MRI contrast agents. In vitro studies demonstrated specific uptake of polypeptide-SPIONs by PSMA expressing cells. In vivo MRI studies found that MRI signals in PSMA-expressing tumors could be specifically enhanced with polypeptide-SPION, and further Prussian blue staining showed heterogeneous deposition of SPIONs in the tumor tissues. Taken altogether, we have developed PSMA-targeting polypeptide-SPIONs that could specifically enhance MRI signal in tumor-bearing mice, which might provide a new strategy for the molecular imaging of PCa. PMID:25927579

  14. In Vivo Molecular MRI Imaging of Prostate Cancer by Targeting PSMA with Polypeptide-Labeled Superparamagnetic Iron Oxide Nanoparticles.

    PubMed

    Zhu, Yunkai; Sun, Ying; Chen, Yaqing; Liu, Weiyong; Jiang, Jun; Guan, Wenbin; Zhang, Zhongyang; Duan, Yourong

    2015-01-01

    The prostate specific membrane antigen (PSMA) is broadly overexpressed on prostate cancer (PCa) cell surfaces. In this study, we report the synthesis, characterization, in vitro binding assay, and in vivo magnetic resonance imaging (MRI) evaluation of PSMA targeting superparamagnetic iron oxide nanoparticles (SPIONs). PSMA-targeting polypeptide CQKHHNYLC was conjugated to SPIONs to form PSMA-targeting molecular MRI contrast agents. In vitro studies demonstrated specific uptake of polypeptide-SPIONs by PSMA expressing cells. In vivo MRI studies found that MRI signals in PSMA-expressing tumors could be specifically enhanced with polypeptide-SPION, and further Prussian blue staining showed heterogeneous deposition of SPIONs in the tumor tissues. Taken altogether, we have developed PSMA-targeting polypeptide-SPIONs that could specifically enhance MRI signal in tumor-bearing mice, which might provide a new strategy for the molecular imaging of PCa. PMID:25927579

  15. Tumor Cell Targeting by Iron Oxide Nanoparticles Is Dominated by Different Factors In Vitro versus In Vivo

    PubMed Central

    NDong, Christian; Tate, Jennifer A.; Kett, Warren C.; Batra, Jaya; Demidenko, Eugene; Lewis, Lionel D.; Hoopes, P. Jack; Gerngross, Tillman U.; Griswold, Karl E.

    2015-01-01

    Realizing the full potential of iron oxide nanoparticles (IONP) for cancer diagnosis and therapy requires selective tumor cell accumulation. Here, we report a systematic analysis of two key determinants for IONP homing to human breast cancers: (i) particle size and (ii) active vs passive targeting. In vitro, molecular targeting to the HER2 receptor was the dominant factor driving cancer cell association. In contrast, size was found to be the key determinant of tumor accumulation in vivo, where molecular targeting increased tumor tissue concentrations for 30 nm but not 100 nm IONP. Similar to the in vitro results, PEGylation did not influence in vivo IONP biodistribution. Thus, the results reported here indicate that the in vitro advantages of molecular targeting may not consistently extend to pre-clinical in vivo settings. These observations may have important implications for the design and clinical translation of advanced, multifunctional, IONP platforms. PMID:25695795

  16. Inhibitory effects and oxidative target site of dibutyl phthalate on Karenia brevis.

    PubMed

    Li, Feng-min; Wu, Miao; Yao, Yuan; Zheng, Xiang; Zhao, Jian; Wang, Zhen-yu; Xing, Bao-shan

    2015-08-01

    The inhibitory action and possible damage mechanism of dibutyl phthalate (DBP) on the red tide algae Karenia brevis were investigated. The results showed that the algae experienced oxidative stress after exposure to 5mgL(-1) DBP. Malondialdehyde (MDA) peaked after 72h, with a value approximately 2.3 times higher than that observed for untreated cells. The superoxide dismutase (SOD) and catalase (CAT) activities significantly increased as an adaptive reaction after 48h. DBP induced the overproduction of reactive oxygen species (ROS), the OH concentration showed a peak of 33UmL(-1) at 48h, and the highest H2O2 content was approximately 250nmol/10(7) cells at 72h; these latter two values were 2.5 and 4.4 times higher than observed for the control, respectively. TEM images showed that a number of small vacuoles or apical tubers were commonly found around the cell membrane, and the membrane structure was ultimately disintegrated. Further experiments were carried out to locate the original ROS production sites following DBP exposure. The activity of CuZn-SOD (a mainly cytosolic isoform, with some also found in chloroplasts) under DBP exposure was approximately 2.5 times higher than the control, whereas the Mn-SOD (mitochondrial isoform) activity was significantly inhibited. No significant difference was observed in the activity of Fe-SOD (chloroplastic isoform). In addition, dicumarol (an inhibitor of the electron transport chain in the plasma membrane) stimulated DBP-induced ROS production, whereas rotenone (an inhibitor of the mitochondria electron transport chain complex I) decreased DBP-induced ROS production. These results suggested that mitochondria could be the main target sites for DBP attack. PMID:25770834

  17. Hyperpolarization-activated ion channels as targets for nitric oxide signalling in deep cerebellar nuclei

    PubMed Central

    Wilson, Gary W; Garthwaite, John

    2010-01-01

    Most biological effects of nitric oxide (NO) in the brain are mediated by guanylyl cyclase-coupled NO receptors, whose activation results in increased intracellular cGMP levels. Apart from protein kinase activation little is known about subsequent cGMP signal transduction. In optic nerve axons, hyperpolarization-activated cyclic nucleotide-modulated cation (HCN) channels, which bind cGMP or cAMP directly, were recently suggested to be a target. The aim here was to test this possibility more directly. Neurones of the rat deep cerebellar nuclei were selected for this purpose, their suitability being attested by immunocytochemistry showing that the principal neurones expressed guanylyl cyclase protein and that NO synthase-containing fibres were abundant in the neuropil. Using whole-cell voltage-clamp recording, HCN channels in the neurones were activated in response to isoprenaline and exogenous cAMP but only occasionally did they respond to NO, although exogenous cGMP was routinely effective. With the less invasive sharp microelectrode recording technique, however, exogenous NO modulated the channels reproducibly, as measured by the size of the HCN channel-mediated voltage sag following hyperpolarization. Moreover, NO also blunted the subsequent rebound depolarizing potentials, consistent with it increasing the hyperpolarization-activated current. Optimizing the whole-cell solution to improve the functioning of NO-activated guanylyl cyclase failed to restore NO sensitivity. Minimizing cellular dialysis by using the perforated-patch technique, however, was successful. The results provide evidence that HCN channels are potential downstream mediators of NO signalling in deep cerebellar nuclei neurones and suggest that the more general importance of this transduction pathway may have been overlooked previously because of unsuitable recording methods. PMID:20529121

  18. Intracellular repair of oxidation-damaged α-synuclein fails to target C-terminal modification sites

    PubMed Central

    Binolfi, Andres; Limatola, Antonio; Verzini, Silvia; Kosten, Jonas; Theillet, Francois-Xavier; May Rose, Honor; Bekei, Beata; Stuiver, Marchel; van Rossum, Marleen; Selenko, Philipp

    2016-01-01

    Cellular oxidative stress serves as a common denominator in many neurodegenerative disorders, including Parkinson's disease. Here we use in-cell NMR spectroscopy to study the fate of the oxidation-damaged Parkinson's disease protein alpha-synuclein (α-Syn) in non-neuronal and neuronal mammalian cells. Specifically, we deliver methionine-oxidized, isotope-enriched α-Syn into cultured cells and follow intracellular protein repair by endogenous enzymes at atomic resolution. We show that N-terminal α-Syn methionines Met1 and Met5 are processed in a stepwise manner, with Met5 being exclusively repaired before Met1. By contrast, C-terminal methionines Met116 and Met127 remain oxidized and are not targeted by cellular enzymes. In turn, persisting oxidative damage in the C-terminus of α-Syn diminishes phosphorylation of Tyr125 by Fyn kinase, which ablates the necessary priming event for Ser129 modification by CK1. These results establish that oxidative stress can lead to the accumulation of chemically and functionally altered α-Syn in cells. PMID:26807843

  19. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    NASA Astrophysics Data System (ADS)

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-04-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers.

  20. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers

    PubMed Central

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  1. Single-wall carbon nanotubes and graphene oxide-based saturable absorbers for low phase noise mode-locked fiber lasers.

    PubMed

    Li, Xiaohui; Wu, Kan; Sun, Zhipei; Meng, Bo; Wang, Yonggang; Wang, Yishan; Yu, Xuechao; Yu, Xia; Zhang, Ying; Shum, Perry Ping; Wang, Qi Jie

    2016-01-01

    Low phase noise mode-locked fiber laser finds important applications in telecommunication, ultrafast sciences, material science, and biology, etc. In this paper, two types of carbon nano-materials, i.e. single-wall carbon nanotube (SWNT) and graphene oxide (GO), are investigated as efficient saturable absorbers (SAs) to achieve low phase noise mode-locked fiber lasers. Various properties of these wall-paper SAs, such as saturable intensity, optical absorption and degree of purity, are found to be key factors determining the performance of the ultrafast pulses. Reduced-noise femtosecond fiber lasers based on such carbon-based SAs are experimentally demonstrated, for which the phase noise has been reduced by more than 10 dB for SWNT SAs and 8 dB for GO SAs at 10 kHz. To the best of our knowledge, this is the first investigation on the relationship between different carbon material based SAs and the phase noise of mode-locked lasers. This work paves the way to generate high-quality low phase noise ultrashort pulses in passively mode-locked fiber lasers. PMID:27126900

  2. Black Beans, Fiber, and Antioxidant Capacity Pilot Study: Examination of Whole Foods vs. Functional Components on Postprandial Metabolic, Oxidative Stress, and Inflammation in Adults with Metabolic Syndrome.

    PubMed

    Reverri, Elizabeth J; Randolph, Jody M; Steinberg, Francene M; Kappagoda, C Tissa; Edirisinghe, Indika; Burton-Freeman, Britt M

    2015-08-01

    Beans (Phaseolus vulgaris) contain bioactive components with functional properties that may modify cardiovascular risk. The aims of this pilot study were to evaluate the ability of black beans to attenuate postprandial metabolic, oxidative stress, and inflammatory responses and determine relative contribution of dietary fiber and antioxidant capacity of beans to the overall effect. In this randomized, controlled, crossover trial, 12 adults with metabolic syndrome (MetS) consumed one of three meals (black bean (BB), fiber matched (FM), and antioxidant capacity matched (AM)) on three occasions that included blood collection before (fasting) and five hours postprandially. Insulin was lower after the BB meal, compared to the FM or AM meals (p < 0.0001). A significant meal × time interaction was observed for plasma antioxidant capacity (p = 0.002) revealing differences over time: AM > BB > FM. Oxidized LDL (oxLDL) was not different by meal, although a trend for declining oxLDL was observed after the BB and AM meals at five hours compared to the FM meal. Triglycerides and interleukin-6 (IL-6) increased in response to meals (p < 0.0001). Inclusion of black beans with a typical Western-style meal attenuates postprandial insulin and moderately enhances postprandial antioxidant endpoints in adults with MetS, which could only be partly explained by fiber content and properties of antioxidant capacity. PMID:26225995

  3. Black Beans, Fiber, and Antioxidant Capacity Pilot Study: Examination of Whole Foods vs. Functional Components on Postprandial Metabolic, Oxidative Stress, and Inflammation in Adults with Metabolic Syndrome

    PubMed Central

    Reverri, Elizabeth J.; Randolph, Jody M.; Steinberg, Francene M.; Kappagoda, C. Tissa; Edirisinghe, Indika; Burton-Freeman, Britt M.

    2015-01-01

    Beans (Phaseolus vulgaris) contain bioactive components with functional properties that may modify cardiovascular risk. The aims of this pilot study were to evaluate the ability of black beans to attenuate postprandial metabolic, oxidative stress, and inflammatory responses and determine relative contribution of dietary fiber and antioxidant capacity of beans to the overall effect. In this randomized, controlled, crossover trial, 12 adults with metabolic syndrome (MetS) consumed one of three meals (black bean (BB), fiber matched (FM), and antioxidant capacity matched (AM)) on three occasions that included blood collection before (fasting) and five hours postprandially. Insulin was lower after the BB meal, compared to the FM or AM meals (p < 0.0001). A significant meal × time interaction was observed for plasma antioxidant capacity (p = 0.002) revealing differences over time: AM > BB > FM. Oxidized LDL (oxLDL) was not different by meal, although a trend for declining oxLDL was observed after the BB and AM meals at five hours compared to the FM meal. Triglycerides and interleukin-6 (IL-6) increased in response to meals (p < 0.0001). Inclusion of black beans with a typical Western-style meal attenuates postprandial insulin and moderately enhances postprandial antioxidant endpoints in adults with MetS, which could only be partly explained by fiber content and properties of antioxidant capacity. PMID:26225995

  4. Nitric oxide as a target of complementary and alternative medicines to prevent and treat inflammation and cancer

    PubMed Central

    Hofseth, Lorne J.

    2009-01-01

    Nitric oxide (NO) and associated reactive nitrogen species (RNS) are involved in many physiological functions. There has been an ongoing debate to whether RNS can inhibit or perpetuate chronic inflammation and associated carcinogenesis. Although the final outcome depends on the genetic make-up of its target, the surrounding microenvironment, the activity and localization of nitric oxide synthase (NOS) isoforms, and overall levels of NO/RNS, evidence is accumulating that in general, RNS drive inflammation and cancers associated with inflammation. To this end, many complementary and alternative medicines (CAMs) that work in chemoprevention associated with chronic inflammation, are inhibitors of excessive NO observed in inflammatory conditions. Here we review recent literature outlining a role of NO/RNS in chronic inflammation and cancer, and point toward NO as one of several targets for the success of CAMs in treating chronic inflammation and cancer associated with this inflammation. PMID:18440130

  5. Cardiac-Oxidized Antigens Are Targets of Immune Recognition by Antibodies and Potential Molecular Determinants in Chagas Disease Pathogenesis

    PubMed Central

    Dhiman, Monisha; Zago, Maria Paola; Nunez, Sonia; Amoroso, Alejandro; Rementeria, Hugo; Dousset, Pierre; Burgos, Federico Nunez; Garg, Nisha Jain

    2012-01-01

    Trypanosoma cruzi elicits reactive oxygen species (ROS) of inflammatory and mitochondrial origin in infected hosts. In this study, we examined ROS-induced oxidative modifications in the heart and determined whether the resultant oxidized cardiac proteins are targets of immune response and of pathological significance in Chagas disease. Heart biopsies from chagasic mice, rats and human patients exhibited, when compared to those from normal controls, a substantial increase in protein 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), carbonyl, and 3-nitrotyrosine (3-NT) adducts. To evaluate whether oxidized proteins gain antigenic properties, heart homogenates or isolated cardiomyocytes were oxidized in vitro and one- or two-dimensional gel electrophoresis (2D-GE)/Western blotting (WB) was performed to investigate the proteomic oxidative changes and recognition of oxidized proteins by sera antibodies in chagasic rodents (mice, rats) and human patients. Human cardiomyocytes exhibited LD50 sensitivity to 30 µM 4-HNE and 100 µM H2O2 at 6 h and 12 h, respectively. In vitro oxidation with 4-HNE or H2O2 resulted in a substantial increase in 4-HNE- and carbonyl-modified proteins that correlated with increased recognition of cardiac (cardiomyocytes) proteins by sera antibodies of chagasic rodents and human patients. 2D-GE/Western blotting followed by MALDI-TOF-MS/MS analysis to identify cardiac proteins that were oxidized and recognized by human chagasic sera yielded 82 unique proteins. We validated the 2D-GE results by enzyme-linked immunosorbent assay (ELISA) and WB and demonstrated that oxidation of recombinant titin enhanced its immunogenicity and recognition by sera antibodies from chagasic hosts (rats and humans). Treatment of infected rats with phenyl-α-tert-butyl nitrone (PBN, antioxidant) resulted in normalized immune detection of cardiac proteins associated with control of cardiac pathology and preservation of heart contractile function in chagasic rats. We

  6. Fiber optic moisture sensor

    DOEpatents

    Kirkham, R.R.

    1984-08-03

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  7. Lung endothelial HO-1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury

    PubMed Central

    Zhang, Yi; Jiang, Ge; Sauler, Maor; Lee, Patty J.

    2013-01-01

    The lung endothelium is a major target for inflammatory and oxidative stress. Heme oxygenase-1 (HO-1) induction is a crucial defense mechanism during oxidant challenges, such as hyperoxia. The role of lung endothelial HO-1during hyperoxia in vivo is not well defined. We engineered lentiviral vectors with microRNA (miRNA) sequences controlled by vascular endothelium cadherin (VE-cad) to study the specific role of lung endothelial HO-1. Wild-type (WT) murine lung endothelial cells (MLECs) or WT mice were treated with lentivirus and exposed to hyperoxia (95% oxygen). We detected HO-1 knockdown (∼55%) specifically in the lung endothelium. MLECs and lungs showed approximately a 2-fold increase in apoptosis and ROS generation after HO-1 silencing. We also demonstrate for the first time that silencing endothelial HO-1 has the same effect on lung injury and survival as silencing HO-1 in multiple lung cell types and that HO-1 regulates caspase 3 activation and autophagy in endothelium during hyperoxia. These studies demonstrate the utility of endothelial-targeted gene silencing in vivo using lentiviral miRNA constructs to assess gene function and that endothelial HO-1 is an important determinant of survival during hyperoxia.—Zhang, Y., Jiang, G., Sauler, M., Lee, P. J. Lung endothelial HO-1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury. PMID:23771928

  8. Sputtering deposition of Al-doped zinc oxide thin films using mixed powder targets

    NASA Astrophysics Data System (ADS)

    Ohshima, Tamiko; Maeda, Takashi; Tanaka, Yuki; Kawasaki, Hiroharu; Yagyu, Yoshihito; Ihara, Takeshi; Suda, Yoshiaki

    2016-01-01

    Sputtering deposition generally uses high-density bulk targets. Such a fabrication process has various problems including deterioration of the material during heating and difficulty in mixing a large number of materials in precise proportions. However, these problems can be solved by using a powder target. In this study, we prepared Al-doped ZnO (AZO) as transparent conductive thin films by radio-frequency magnetron sputtering with powder and bulk targets. Both the powder and bulk targets formed crystalline structures. The ZnO (002) peak was observed in the X-ray diffraction measurements. The mean transparency and resistivity of the films prepared with the powder target were 82% and 0.548 Ω · cm, respectively. The deposition rate with the powder target was lower than that with the bulk target.

  9. The Immature Fiber Mutant Phenotype of Cotton (Gossypium hirsutum) is Linked to a 22-bp Frame-shift Deletion in a Mitochondria Targeted Pentatricopeptide Repeat Gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton seed trichomes are the globally most important source of natural fibers. The major fiber thickness properties influence the price of the raw material and the quality of the finished product. The recessive immature fiber (im) gene reduces the degree of fiber cell wall thickening by a process...

  10. THE PROTEASOME IS A TARGET OF OXIDATIVE DAMAGE IN HUMAN RETINA PIGMENT EPITHELIAL CELLS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Purpose: Dysfunction of the ubiquitin-proteasome pathway (UPP) is associated with several age-related degenerative diseases. The objective of this study is to investigate the effect of oxidative stress on the UPP in retina pigment epithelial cells. Methods: To mimic physiological oxidative stress...

  11. Mitochondria-targeted Ogg1 and Aconitase-2 Prevent Oxidant-induced Mitochondrial DNA Damage in Alveolar Epithelial Cells*

    PubMed Central

    Kim, Seok-Jo; Cheresh, Paul; Williams, David; Cheng, Yuan; Ridge, Karen; Schumacker, Paul T.; Weitzman, Sigmund; Bohr, Vilhelm A.; Kamp, David W.

    2014-01-01

    Mitochondria-targeted human 8-oxoguanine DNA glycosylase (mt-hOgg1) and aconitase-2 (Aco-2) each reduce oxidant-induced alveolar epithelial cell (AEC) apoptosis, but it is unclear whether protection occurs by preventing AEC mitochondrial DNA (mtDNA) damage. Using quantitative PCR-based measurements of mitochondrial and nuclear DNA damage, mtDNA damage was preferentially noted in AEC after exposure to oxidative stress (e.g. amosite asbestos (5–25 μg/cm2) or H2O2 (100–250 μm)) for 24 h. Overexpression of wild-type mt-hOgg1 or mt-long α/β 317–323 hOgg1 mutant incapable of DNA repair (mt-hOgg1-Mut) each blocked A549 cell oxidant-induced mtDNA damage, mitochondrial p53 translocation, and intrinsic apoptosis as assessed by DNA fragmentation and cleaved caspase-9. In contrast, compared with controls, knockdown of Ogg1 (using Ogg1 shRNA in A549 cells or primary alveolar type 2 cells from ogg1−/− mice) augmented mtDNA lesions and intrinsic apoptosis at base line, and these effects were increased further after exposure to oxidative stress. Notably, overexpression of Aco-2 reduced oxidant-induced mtDNA lesions, mitochondrial p53 translocation, and apoptosis, whereas siRNA for Aco-2 (siAco-2) enhanced mtDNA damage, mitochondrial p53 translocation, and apoptosis. Finally, siAco-2 attenuated the protective effects of mt-hOgg1-Mut but not wild-type mt-hOgg1 against oxidant-induced mtDNA damage and apoptosis. Collectively, these data demonstrate a novel role for mt-hOgg1 and Aco-2 in preserving AEC mtDNA integrity, thereby preventing oxidant-induced mitochondrial dysfunction, p53 mitochondrial translocation, and intrinsic apoptosis. Furthermore, mt-hOgg1 chaperoning of Aco-2 in preventing oxidant-mediated mtDNA damage and apoptosis may afford an innovative target for the molecular events underlying oxidant-induced toxicity. PMID:24429287

  12. Laser Desorption/Ionization Mass Spectrometry (LDI-MS) of Lipids with Iron Oxide Nanoparticle-Coated Targets.

    PubMed

    Kusano, Maiko; Kawabata, Shin-Ichirou; Tamura, Yusuke; Mizoguchi, Daigou; Murouchi, Masato; Kawasaki, Hideya; Arakawa, Ryuichi; Tanaka, Koichi

    2014-01-01

    Iron oxide nanoparticle (NP)-coated target plates were employed for the direct detection and analysis of low molecular weight lipids by laser desorption/ionization (LDI) mass spectrometry (MS). We have demonstrated that the use of the iron oxide NP-coated target provides a simple, direct, and rapid detection method for lipid standards and epidermal surface lipids without any cumbersome sample pretreatment as well as mass spectra that are free of background matrix peaks. Lipid standards (1-stearoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycerol, 1-palmitoyl-2-oleoyl-3-linoleoyl-rac-glycerol, 1,2-distearoyl-sn-glycero-3-phosphocholine) were detected as either protonated or cationated species. Clean MS/MS spectra for each lipid were also successfully obtained. Pre-MS surface cleaning of the target plates with UV-ozone treatment successfully removed organic contaminants that would interfere with the mass spectra especially in the low molecular weight region. Preliminary application of the presented target plate to the detection of endogenous lipids in latent fingerprints showed promising results and for potential use in the visualization and chemical composition determination of latent fingerprints by nanoparticle assistance. PMID:24860715

  13. Magnetic Targeting of Novel Heparinized Iron Oxide Nanoparticles Evaluated in a 9L-glioma mouse model

    PubMed Central

    Zhang, Jian; Shin, Meong Cheol; Yang, Victor C.

    2013-01-01

    Purpose A novel PEGylated and heparinized magnetic iron oxide nano-platform (DNPH) was synthesized for simultaneous magnetic resonance imaging (MRI) and tumor targeting. Methods Starch-coated magnetic iron oxide nanoparticles (“D”) were crosslinked, aminated (DN) and then simultaneously PEGylated and heparinized with different feed ratios of PEG and heparin (DNPH1-4). DNPH products were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID). The magentic targeting of DNPH3, with appropriate amounts of conjugated PEG and heparin, in a mouse 9L-glioma subcutaneous tumor model was confirmed by magnetic resonance imaging (MRI)/electron spin resonance (ESR). Results DNPH3 showed long circulating properties in vivo (half-life > 8 h, more than 60-fold longer than that of parent D) and low reticuloendothelial system (RES) recognition in liver and spleen. Protamine, a model cationic protein, was efficiently loaded onto DNPH3 with a maxium loading content of 26.4 μg/mg Fe. Magnetic capture of DNPH3 in tumor site with optimized conditions (I.D. of 12 mg/kg, targeting time of 45 min) was up to 29.42 μg Fe/g tissue (12.26% I.D./g tissue). Conclusion DNPH3 showed the potential to be used as a platform for cationic proteins for simultaneous tumor targeting and imaging. PMID:24065589

  14. Superparamagnetic iron oxide nanoparticles for MR imaging of pancreatic cancer: Potential for early diagnosis through targeted strategies.

    PubMed

    Zhang, Chongjie; Yan, Yuzhong; Zou, Qi; Chen, Jie; Li, Chunsheng

    2016-03-01

    Superparamagnetic iron oxide nanoparticles (SPION)-based magnetic resonance imaging is a powerful, noninvasive tool in biomedical imaging. The recent embedding of SPIO in nanoencapsulations that had different controllable surface properties has now made it possible to use SPIO in the imaging of metabolic processes. The two major issues to realize maximized and selective SPIO cancer targeting are the minimization of macrophage uptake and the preferential binding to cancerous cells over healthy neighbor cells. The utility of SPIO has been shown in clinical applications using a series of marketed SPION-based contrast agents. Applications have ranged from detecting inflammatory diseases to the specific identification of cell surface markers expressed on tumors. This review focuses on iron-oxide-based nanoparticles, to include the physiochemical properties of SPION surface engineering and its synthetic methods as well as SPIO imaging applications and specifically targeted SPIO conjugates (e.g. targeted probes) for labeling cancerous, cell-surface molecules. As a specific application of this technology, we discuss its use in the imaging of pancreatic duct adenocarcinoma in addition to its potential for use in early diagnosis through targeted strategies. PMID:26663873

  15. Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach

    NASA Astrophysics Data System (ADS)

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; van Dorsselaer, Alain; Rabilloud, Thierry

    2014-05-01

    Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate

  16. The rationale for preventing cancer cachexia: targeting excessive fatty acid oxidation.

    PubMed

    Qian, Chao-Nan

    2016-01-01

    Cachexia commonly occurs at the terminal stage of cancer and has largely unclear molecular mechanisms. A recent study published in Nature Medicine, entitled "Excessive fatty acid oxidation induces muscle atrophy in cancer cachexia," reveals that cachectic cancer cells can secrete multiple cytokines that induce excessive fatty acid oxidation, which is responsible for muscle loss in cancer cachexia. Inhibition of fatty acid oxidation using etomoxir can increase muscle mass and body weight in cancer cachexia animal models. The usage of stable cachexia animal models is also discussed in this research highlight. PMID:27443316

  17. Health Risks of Space Exploration: Targeted and Nontargeted Oxidative Injury by High-Charge and High-Energy Particles

    PubMed Central

    Li, Min; Gonon, Géraldine; Buonanno, Manuela; Autsavapromporn, Narongchai; de Toledo, Sonia M.; Pain, Debkumar

    2014-01-01

    Abstract Significance: During deep space travel, astronauts are often exposed to high atomic number (Z) and high-energy (E) (high charge and high energy [HZE]) particles. On interaction with cells, these particles cause severe oxidative injury and result in unique biological responses. When cell populations are exposed to low fluences of HZE particles, a significant fraction of the cells are not traversed by a primary radiation track, and yet, oxidative stress induced in the targeted cells may spread to nearby bystander cells. The long-term effects are more complex because the oxidative effects persist in progeny of the targeted and affected bystander cells, which promote genomic instability and may increase the risk of age-related cancer and degenerative diseases. Recent Advances: Greater understanding of the spatial and temporal features of reactive oxygen species bursts along the tracks of HZE particles, and the availability of facilities that can simulate exposure to space radiations have supported the characterization of oxidative stress from targeted and nontargeted effects. Critical Issues: The significance of secondary radiations generated from the interaction of the primary HZE particles with biological material and the mitigating effects of antioxidants on various cellular injuries are central to understanding nontargeted effects and alleviating tissue injury. Future Directions: Elucidation of the mechanisms underlying the cellular responses to HZE particles, particularly under reduced gravity and situations of exposure to additional radiations, such as protons, should be useful in reducing the uncertainty associated with current models for predicting long-term health risks of space radiation. These studies are also relevant to hadron therapy of cancer. Antioxid. Redox Signal. 20, 1501–1523. PMID:24111926

  18. Furan oxidation based cross-linking: a new approach for the study and targeting of nucleic acid and protein interactions.

    PubMed

    Carrette, L L G; Gyssels, E; De Laet, N; Madder, A

    2016-01-28

    Furan mediated nucleic acid cross-linking, initially developed for DNA interstrand duplex cross-linking, has matured into a versatile tool for the study of protein and nucleic acid interactions, ready to face its applications. The methodology was initially developed for easy and clean chemical generation of DNA interstrand cross-linked duplexes, but has been further expanded for use with other probes, targets and triggers, now allowing mild biologically significant cross-linking with potential therapeutic benefit. It was shown that the methodology could be repurposed for RNA interstrand cross-linking, which is very relevant in today's antisense approaches or miRNA target identification endeavors. This further illustrates the furan oxidation method's generality and mildness, especially when using red light for oxidation. A complementary antigene approach has been explored through duplex targeting with furan modified triplex forming oligonucleotides (TFOs) and DNA binding proteins. Also targeting of peptides and proteins by furan-modified DNA and peptides has been explored. Thorough methodology examination exploring variable reaction conditions in combination with a series of different furan-modified building blocks and application of different activation signals resulted in a detailed understanding of the mechanisms involved and factors influencing the yield and selectivity of the reaction. In order to draw the bigger picture of the scope and limitations of furan-oxidation cross-linking, we here provide a unique side by side comparison and discussion of our published data, supplemented with unpublished results, providing a clear performance report of the currently established furan toolbox and its application potential in various biomacromolecular complexes. PMID:26679922

  19. Neuroinflammation and Oxidative Stress in Diabetic Neuropathy: Futuristic Strategies Based on These Targets

    PubMed Central

    Sandireddy, Reddemma; Yerra, Veera Ganesh; Areti, Aparna; Komirishetty, Prashanth

    2014-01-01

    In Diabetes, the chronic hyperglycemia and associated complications affecting peripheral nerves are one of the most commonly occurring microvascular complications with an overall prevalence of 50–60%. Among the vascular complications of diabetes, diabetic neuropathy is the most painful and disabling, fatal complication affecting the quality of life in patients. Several theories of etiologies surfaced down the lane, amongst which the oxidative stress mediated damage in neurons and surrounding glial cell has gained attention as one of the vital mechanisms in the pathogenesis of neuropathy. Mitochondria induced ROS and other oxidants are responsible for altering the balance between oxidants and innate antioxidant defence of the body. Oxidative-nitrosative stress not only activates the major pathways namely, polyol pathway flux, advanced glycation end products formation, activation of protein kinase C, and overactivity of the hexosamine pathway, but also initiates and amplifies neuroinflammation. The cross talk between oxidative stress and inflammation is due to the activation of NF-κB and AP-1 and inhibition of Nrf2, peroxynitrite mediate endothelial dysfunction, altered NO levels, and macrophage migration. These all culminate in the production of proinflammatory cytokines which are responsible for nerve tissue damage and debilitating neuropathies. This review focuses on the relationship between oxidative stress and neuroinflammation in the development and progression of diabetic neuropathy. PMID:24883061

  20. Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach.

    PubMed

    Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; Van Dorsselaer, Alain; Rabilloud, Thierry

    2014-06-01

    Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations. PMID:24788578

  1. THE PROTEIN TARGETING FACTOR GET3 FUNCTIONS AS AN ATP-INDEPENDENT CHAPERONE UNDER OXIDATIVE STRESS CONDITIONS

    PubMed Central

    Voth, Wilhelm; Schick, Markus; Gates, Stephanie; Li, Sheng; Vilardi, Fabio; Gostimskaya, Irina; Southworth, Daniel R.; Schwappach, Blanche; Jakob, Ursula

    2014-01-01

    Summary Exposure of cells to reactive oxygen species (ROS) causes a rapid and significant drop in intracellular ATP-levels. This energy depletion negatively affects ATP-dependent chaperone systems, making ROS-mediated protein unfolding and aggregation a potentially very challenging problem. Here we show that Get3, a protein involved in ATP-dependent targeting of tail-anchored (TA) proteins under non-stress conditions, turns into an effective ATP-in dependent chaperone when oxidized. Activation of Get3’s chaperone function, which is a fully reversible process, involves disulfide bond formation, metal release and its conversion into distinct, higher oligomeric structures. Mutational studies demonstrate that the chaperone activity of Get3 is functionally distinct from and likely mutually exclusive with its targeting function, and responsible for the oxidative stress sensitive phenotype that has long been noted for yeast cells lacking functional Get3. These results provide convincing evidence that Get3 functions as a redox regulated chaperone, effectively protecting eukaryotic cells against oxidative protein damage. PMID:25242142

  2. High electrical resistivity carbon/graphite fibers

    NASA Technical Reports Server (NTRS)

    Vogel, F. L.; Forsman, W. C.

    1980-01-01

    Carbon/graphite fibers were chemically oxidized in the liquid phase to fibers of graphite oxide. Resistivity increases as high as 10,000 times were obtained, the oxidized fiber decomposed on exposure to atmosphere. A factor of 1,000 remained as a stable increment. The largest change observed was 1,000,000 times. Best results were obtained on the most highly graphitized fibers. Electrochemical oxidation yielded a lower increase--about 10 times, but provided a controllable method of synthesis and insight to the mechanism of reaction. Tensile tests indicated that the strength of the fiber on oxidation was decreased by no more than 25 percent.

  3. Targeted mass spectrometry methods for detecting oxidative post-translational modifications.

    PubMed

    Tveen-Jensen, Karina; Reis, Ana; Spickett, Corinne M; Pitt, Andrew R

    2014-10-01

    Oxidative post-translational modifications (oxPTMs) can alter the function of proteins, and are important in the redox regulation of cell behaviour. The most informative technique to detect and locate oxPTMs within proteins is mass spectrometry (MS). However, proteomic MS data are usually searched against theoretical databases using statistical search engines, and the occurrence of unspecified or multiple modifications, or other unexpected features, can lead to failure to detect the modifications and erroneous identifications of oxPTMs. We have developed a new approach for mining data from accurate mass instruments that allows multiple modifications to be examined. Accurate mass extracted ion chromatograms (XIC) for specific reporter ions from peptides containing oxPTMs were generated from standard LC-MSMS data acquired on a rapid-scanning high-resolution mass spectrometer (ABSciex 5600 Triple TOF). The method was tested using proteins from human plasma or isolated LDL. A variety of modifications including chlorotyrosine, nitrotyrosine, kynurenine, oxidation of lysine, and oxidized phospholipid adducts were detected. For example, the use of a reporter ion at 184.074Da/e, corresponding to phosphocholine, was used to identify for the first time intact oxidized phosphatidylcholine adducts on LDL. In all cases the modifications were confirmed by manual sequencing. ApoB-100 containing oxidized lipid adducts was detected even in healthy human samples, as well as LDL from patients with chronic kidney disease. The accurate mass XIC method gave a lower false positive rate than normal database searching using statistical search engines, and identified more oxidatively modified peptides. A major advantage was that additional modifications could be searched after data collection, and multiple modifications on a single peptide identified. The oxPTMs present on albumin and ApoB-100 have potential as indicators of oxidative damage in ageing or inflammatory diseases. PMID:26461406

  4. Novel electrochemical sensing platform for quantitative monitoring of Hg(II) on DNA-assembled graphene oxide with target recycling.

    PubMed

    Lu, Minghua; Xiao, Rui; Zhang, Xiaona; Niu, Jiahua; Zhang, Xiaoting; Wang, Youmei

    2016-11-15

    This work designs a new electrochemical sensing platform for the quantitative monitoring of mercury ion (Hg(2+)) on poly-T(15) oligonucleotide-functionalized graphene oxide by coupling with DNase I-assisted target recycling amplification. The assay was carried out on the basis of T-Hg(2+)-T coordination chemistry by using target-induced dissociation of indicator-labeled poly-T(15) oligonucleotide from graphene oxide nanosheets. The electronic signal was amplified through DNase I-triggered target recycling. Experimental results indicated that the amperometric response of DNA-based sensing platform deceased with the increasing Hg(2+) concentration in the sample, and has a detection limit of 0.12nM with a dynamic working range of up to 50nM. Our strategy afforded exquisite selectivity for Hg(2+) against other environmentally related metal ions. More significantly, this methodology displayed high reproducibility and acceptable accuracy, thus representing an optional sensing scheme for the screening of Hg(2+) in environmental water samples. PMID:27179567

  5. Methodology for use of mitochondria-targeted cations in the field of oxidative stress-related research.

    PubMed

    Vyssokikh, Mikhail Y; Antonenko, Yury N; Lyamzaev, Konstantin G; Rokitskaya, Tatyana I; Skulachev, Vladimir P

    2015-01-01

    For many pathological conditions, reactive oxygen species (ROS) generated in mitochondria are considered to have a role as a trigger. When mitochondrial ROS (mROS) are formed in the inner mitochondrial membrane, they initiate free radical-mediated chain reactions of lipid peroxidation and are thus especially damaging. The consequences of membrane damage are decreased electrical resistance of the membrane, oxidative damage to cardiolipin (a mitochondria specific lipid essential for functioning of respiratory chain proteins and H(+)-ATP synthase), and damage to mitochondrial DNA localized in close vicinity to the inner membrane, with consequent mitochondrial dysfunction and induction of apoptotic cascade and cell death. To target the starting point of such undesirable events, antioxidants conjugated with mitochondria-targeted, membrane-penetrating cations can be used to scavenge ROS inside mitochondria. The most demonstrative indications favoring this conclusion originate from recent discoveries of the in vivo effects of such cations belonging to the MitoQ and SkQ groups. Here we describe some essential methodological aspects of the application of mitochondria-targeted cations promising in treating oxidative stress-related pathologies. PMID:25634274

  6. In vivo fiber-based multicolor photoacoustic detection and photothermal purging of metastasis in sentinel lymph nodes targeted by nanoparticles.

    PubMed

    Galanzha, Ekaterina I; Kokoska, Mimi S; Shashkov, Evgeny V; Kim, Jin-Woo; Tuchin, Valery V; Zharov, Vladimir P

    2009-09-01

    This report introduces a novel diagnostic and therapeutic platform for in vivo non-invasive detection and treatment of metastases in sentinel lymph nodes (SLNs) at single cell level using an integrated system of multicolor photoacoustic (PA) lymph flow cytometry, PA lymphography, absorption image cytometry, and photothermal (PT) therapy. A melanoma-bearing mouse model was used to demonstrate the capability of this platform for real-time lymphatic mapping, counting of disseminated tumor cells (DTCs) in prenodal lymphatics, and detecting metastasis in SLNs and its purging. The detection and ablation of non-pigmented breast cancer cells in SLNs was achieved by labeling them with nanoparticles. The association between DTC count and SLN metastasis progression supports lymphatic DTCs as a novel prognostic marker of metastasis. The fiber-based portable PA device may replace the conventional SLN(s) excision and histology-based staging. The earliest detection of DTCs in the lymphatic vessels before the establishment of nodal metastasis may prevent metastasis by well-timed ablation of DTCs. PMID:19743443

  7. An aptamer-targeting photoresponsive drug delivery system using ``off-on'' graphene oxide wrapped mesoporous silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Tang, Yuxia; Hu, Hao; Zhang, Molly Gu; Song, Jibin; Nie, Liming; Wang, Shouju; Niu, Gang; Huang, Peng; Lu, Guangming; Chen, Xiaoyuan

    2015-03-01

    We have developed a novel aptamer-targeting photoresponsive drug delivery system by non-covalent assembly of a Cy5.5-AS1411 aptamer conjugate on the surface of graphene oxide wrapped doxorubicin (Dox)-loaded mesoporous silica nanoparticles (MSN-Dox@GO-Apt) for light-mediated drug release and aptamer-targeted cancer therapy. The two ``off-on'' switches of the MSN-Dox@GO-Apt were controlled by aptamer targeting and light triggering, respectively. The Cy5.5-AS1411 ligand provides MSN-Dox@GO-Apt with nucleolin specific targeting and real-time indicator abilities by ``off-on'' Cy5.5 fluorescence recovery. The GO acts as a gatekeeper to prevent the loaded Dox from leaking in the absence of laser irradiation, and to control the Dox release in response to laser irradiation. When the GO wrapping falls off upon laser irradiation, the ``off-on'' photoresponsive drug delivery system is activated, thus inducing chemotherapy. Interestingly, with an increase in laser power, the synergism of chemotherapy and photothermal therapy in a single MSN-Dox@GO-Apt platform led to much more effective cancer cell killing than monotherapies, providing a new approach for treatment against cancer.We have developed a novel aptamer-targeting photoresponsive drug delivery system by non-covalent assembly of a Cy5.5-AS1411 aptamer conjugate on the surface of graphene oxide wrapped doxorubicin (Dox)-loaded mesoporous silica nanoparticles (MSN-Dox@GO-Apt) for light-mediated drug release and aptamer-targeted cancer therapy. The two ``off-on'' switches of the MSN-Dox@GO-Apt were controlled by aptamer targeting and light triggering, respectively. The Cy5.5-AS1411 ligand provides MSN-Dox@GO-Apt with nucleolin specific targeting and real-time indicator abilities by ``off-on'' Cy5.5 fluorescence recovery. The GO acts as a gatekeeper to prevent the loaded Dox from leaking in the absence of laser irradiation, and to control the Dox release in response to laser irradiation. When the GO wrapping falls off upon

  8. The Oxidation Kinetics of Continuous Carbon Fibers in a Cracked Ceramic Matrix Composite. Degree awarded by Case Western Reserve Univ., May 2000

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2001-01-01

    Experimental observations and results suggest two primary regimes as a function of temperature, i.e., diffusion and reaction controlled kinetics. Thermogravimetric analysis of carbon fiber in flowing oxygen gave an activation energy of 64.1 kJ/mol in the temperature range of 500 to 600 C and an apparent activation energy of 7.6 kJ/mol for temperatures from 600 to 1400 C. When C/SiC composite material was unstressed, matrix effects at temperatures from 900 to 1400 C protected the internal fibers. When under stress, self-protection was not observed. Increasing the stress from 10 to 25 ksi caused a 67 to 82 percent reduction in times to failure at temperatures from 750 to 1500 C. Based on experimental results, observation, and theory, a finite difference model was developed, which simulates the diffusion of oxygen into a matrix crack that is bridged by carbon fibers. The model allows the influence of important variables on oxidation kinetics to be studied systematically, i.e., temperature, reaction rate constant, diffusion coefficient, environment, and sample geometry.

  9. Application of poly(dimethylsiloxane) fiber sol-gel coated onto NiTi alloy electrodeposited with zirconium oxide for the determination of organochlorine pesticides in herbal infusions.

    PubMed

    Budziak, Dilma; Martendal, Edmar; Carasek, Eduardo

    2008-08-01

    A PDMS fiber sol-gel coated onto an NiTi alloy previously electrodeposited with zirconium oxide (named NiTi-ZrO(2)-PDMS) was applied to the determination of organochlorine pesticides (OCPs) in infusions of peppermint (Mentha piperita L.), lemon grass (Cymbopogon citratus Stapf), chamomile (Matricaria recutita L.), lemon balm (Melissa officinalis L.), and anise seeds (Pimpinella anisum L.). Salting-out effect, extraction time, and extraction temperature were optimized firstly by means of a full-factorial design and then using a Doehlert matrix. No salt addition and 50 min of extraction at 70 degrees C were the optimum conditions. Satisfactory LODs in the range of 2-17 ng/L, as well as good correlation coefficients (at least 0.9981) in the linear range studied, were obtained. Calibration was successfully applied using an infusion of M. recutita L. and recovery tests were performed to ensure the accuracy of the method, with values in the range of 77-120%. Comparison of the NiTi-ZrO(2)-PDMS with commercially available PDMS fibers showed that the proposed fiber has an extraction efficiency comparable to that of PDMS 30 microm for the compounds evaluated, demonstrating its potential applicability. PMID:18666186

  10. Mitochondria as an easy target to oxidative stress events in Parkinson's disease.

    PubMed

    Reale, Marcella; Pesce, Mirko; Priyadarshini, Medha; Kamal, Mohammad A; Patruno, Antonia

    2012-06-01

    Parkinson's disease (PD) is related to excess production of reactive oxygen species (ROS) or inadequate and impaired detoxification by endogenous antioxidants, alterations in catecholamine metabolism, alterations in mitochondrial electron transfer function, and enhanced iron deposition in the substantia nigra. The concept that oxidative stress is an important mechanism underlying the degeneration of dopaminergic (DAergic) neurons is reinforced by data documenting that high levels of lipid peroxidation, increased oxidation of proteins and DNA and depletion of glutathione are observed in postmortem studies of brain tissues of PD patients. Tyrosine hydroxylase (TH) is an important neuronal enzyme that, in the presence of tetrahydrobiopterin, catalyzes the initial and rate-limiting step in the biosynthesis of the catecholamine neurotransmitters dopamine (DA) and norepinephrine, and is frequently used as a marker of DAergic neuronal loss in animal models of PD. The role for TH as generators of ROS are highly relevant to PD because ROS have been proposed to contribute to the neurodegeneration of DA neurons. Oxidants and superoxide radicals are produced as byproducts of oxidative phosphorylation, making mitochondria the main site of ROS generation within the cell and the site of the first line of defence against oxidative stress. ROS can affect mitochondrial DNA (mtDNA) causing modulation in synthesis of electron transport chain (ETC) components, decreased ATP production, and increased leakage of ROS. PMID:22483310

  11. Inhibition of murine T-cell responses by anti-oxidants: the targets of lipo-oxygenase pathway inhibitors.

    PubMed Central

    Dornand, J; Gerber, M

    1989-01-01

    We have previously established that oxidative phenomena are involved in human T-cell activation (Sekkat, Dornand & Gerber, 1988). In the present work we have studied the effect of different anti-oxidants (scavengers of O2-, .OH and lipo-oxygenase inhibitors) on the stimulation of murine T cells. We report here that all the anti-oxidants used suppressed T-lymphocyte proliferation and IL-2 synthesis, the former effect resulting very likely from the latter. This inhibition was concomitant with the triggering of activation. We also demonstrate that the various anti-oxidants have different biochemical targets. Unlike the other compounds, the phenolic drugs nordihydroguaiaretic acid (NDGA) and butylated hydroxyanisole (BHA), which block lipid peroxidation, affect both signals triggered by the binding of lectin to its receptors: they suppress the rise of intracellular free calcium concentration and inhibit some of the events, depending on the sole protein kinase C activation, namely IL-2 receptor expression and phorbol myristate acetate (PMA)-induced pH change. Our results are discussed within the framework of a possible involvement of reactive oxygen species and of arachidonic acid derivative(s) in T-cell activation and IL-2 production. PMID:2512249

  12. Inhibition of murine T-cell responses by anti-oxidants: the targets of lipo-oxygenase pathway inhibitors.

    PubMed

    Dornand, J; Gerber, M

    1989-11-01

    We have previously established that oxidative phenomena are involved in human T-cell activation (Sekkat, Dornand & Gerber, 1988). In the present work we have studied the effect of different anti-oxidants (scavengers of O2-, .OH and lipo-oxygenase inhibitors) on the stimulation of murine T cells. We report here that all the anti-oxidants used suppressed T-lymphocyte proliferation and IL-2 synthesis, the former effect resulting very likely from the latter. This inhibition was concomitant with the triggering of activation. We also demonstrate that the various anti-oxidants have different biochemical targets. Unlike the other compounds, the phenolic drugs nordihydroguaiaretic acid (NDGA) and butylated hydroxyanisole (BHA), which block lipid peroxidation, affect both signals triggered by the binding of lectin to its receptors: they suppress the rise of intracellular free calcium concentration and inhibit some of the events, depending on the sole protein kinase C activation, namely IL-2 receptor expression and phorbol myristate acetate (PMA)-induced pH change. Our results are discussed within the framework of a possible involvement of reactive oxygen species and of arachidonic acid derivative(s) in T-cell activation and IL-2 production. PMID:2512249

  13. Oxidative DNA damage caused by inflammation may link to stress-induced non-targeted effects

    PubMed Central

    Sprung, Carl N.; Ivashkevich, Alesia; Forrester, Helen B.; Redon, Christophe E.; Georgakilas, Alexandros; Martin, Olga A.

    2013-01-01

    A spectrum of radiation-induced non-targeted effects has been reported during the last two decades since Nagasawa and Little first described a phenomenon in cultured cells that was later called the “bystander effect”. These non-targeted effects include radiotherapy-related abscopal effects, where changes in organs or tissues occur distant from the irradiated region. The spectrum of non-targeted effects continue to broaden over time and now embrace many types of exogenous and endogenous stressors that induce a systemic genotoxic response including a widely studied tumor microenvironment. Here we discuss processes and factors leading to DNA damage induction in non-targeted cells and tissues and highlight similarities in the regulation of systemic effects caused by different stressors. PMID:24041866

  14. The mitochondrial permeability transition pore regulates nitric oxide-mediated apoptosis of neurons induced by target deprivation.

    PubMed

    Martin, Lee J; Adams, Neal A; Pan, Yan; Price, Ann; Wong, Margaret

    2011-01-01

    Ablation of mouse occipital cortex induces precisely timed and uniform p53-modulated and Bax-dependent apoptosis of thalamocortical projection neurons in the dorsal lateral geniculate nucleus (LGN) by 7 d after lesion. We tested the hypothesis that this neuronal apoptosis is initiated by oxidative stress and the mitochondrial permeability transition pore (mPTP). Preapoptotic LGN neurons accumulate mitochondria, Zn(2+) and Ca(2+), and generate higher levels of reactive oxygen species (ROS), including superoxide, nitric oxide (NO), and peroxynitrite, than LGN neurons with an intact cortical target. Preapoptosis of LGN neurons is associated with increased formation of protein carbonyls, protein nitration, and protein S-nitrosylation. Genetic deletion of nitric oxide synthase 1 (nos1) and inhibition of NOS1 with nitroindazole protected LGN neurons from apoptosis, revealing NO as a mediator. Putative components of the mPTP are expressed in mouse LGN, including the voltage-dependent anion channel (VDAC), adenine nucleotide translocator (ANT), and cyclophilin D (CyPD). Nitration of CyPD and ANT in LGN mitochondria occurs by 2 d after cortical injury. Chemical cross-linking showed that LGN neuron preapoptosis is associated with formation of CyPD and VDAC oligomers, consistent with mPTP formation. Mice without CyPD are rescued from neuron apoptosis as are mice treated with the mPTP inhibitors TRO-19622 (cholest-4-en-3-one oxime) and TAT-Bcl-X(L)-BH4. Manipulation of the mPTP markedly attenuated the early preapoptotic production of reactive oxygen/nitrogen species in target-deprived neurons. Our results demonstrate in adult mouse brain neurons that the mPTP functions to enhance ROS production and the mPTP and NO trigger apoptosis; thus, the mPTP is a target for neuroprotection in vivo. PMID:21209222

  15. Local delivery of nitric oxide: targeted delivery of therapeutics to bone and connective tissues

    PubMed Central

    Nichols, Scott P.; Storm, Wesley L.; Koh, Ahyeon; Schoenfisch, Mark H.

    2012-01-01

    Non-invasive treatment of injuries and disorders affecting bones and connective tissue is a significant challenge facing the medical community. A treatment route that has recently been proposed is nitric oxide (NO) therapy. Nitric oxide plays several roles in physiology with many conditions lacking adequate levels of NO. As NO is a radical, localized delivery via NO donors is essential to promoting biological activity. Herein, we review current literature related to therapeutic NO delivery in the treatment of bone, skin and tendon repair. PMID:22433782

  16. Oxidative damage to specific proteins in replicative and chronological-aged Saccharomyces cerevisiae: common targets and prevention by calorie restriction.

    PubMed

    Reverter-Branchat, Gemma; Cabiscol, Elisa; Tamarit, Jordi; Ros, Joaquim

    2004-07-23

    Oxidative modifications of cellular components have been described as one of the main contributions to aged phenotype. In Saccharomyces cerevisiae, two distinct life spans can be considered, replicative and chronological. The relationship between both aging models is still not clear despite suggestions that these phenomena may be related. In this work, we show that replicative and chronological-aged yeast cells are affected by an oxidative stress situation demonstrated by increased protein carbonylation when compared with young cells. The data on the identification of these oxidatively modified proteins gives clues to better understand cellular dysfunction that occurs during aging. Strikingly, although in both aging models metabolic differences are important, major targets are almost the same. Common targets include stress resistance proteins (Hsp60 and Hsp70) and enzymes involved in glucose metabolism such as enolase, glyceraldehydes-3-P dehydrogenase, fructose-1,6-biphosphate aldolase, pyruvate decarboxylase, and alcohol dehydrogenase. In both aging models, calorie restriction results in decreased damage to these proteins. In addition, chronological-aged cells grown under glucose restriction displayed lowered levels of lipid peroxidation product lipofuscin. Intracellular iron concentration is kept almost unchanged, whereas in non-restricted cells, the values increase up 4-5 times. The pro-oxidant effects of such increased iron concentration would account for the damage observed. Also, calorie-restricted cells show undamaged catalase, which clearly appears carbonylated in cells grown at a high glucose concentration. These results may explain lengthening of the viability of chronological-aged cells and could have an important role in replicative life span extension by calorie restriction. PMID:15166233

  17. VEGF-loaded graphene oxide as theranostics for multi-modality imaging-monitored targeting therapeutic angiogenesis of ischemic muscle

    NASA Astrophysics Data System (ADS)

    Sun, Zhongchan; Huang, Peng; Tong, Guang; Lin, Jing; Jin, Albert; Rong, Pengfei; Zhu, Lei; Nie, Liming; Niu, Gang; Cao, Feng; Chen, Xiaoyuan

    2013-07-01

    Herein we report the design and synthesis of multifunctional VEGF-loaded IR800-conjugated graphene oxide (GO-IR800-VEGF) for multi-modality imaging-monitored therapeutic angiogenesis of ischemic muscle. The as-prepared GO-IR800-VEGF positively targets VEGF receptors, maintains an elevated level of VEGF in ischemic tissues for a prolonged time, and finally leads to remarkable therapeutic angiogenesis of ischemic muscle. Although more efforts are required to further understand the in vivo behaviors and the long-term toxicology of GO, our work demonstrates the success of using GO for efficient VEGF delivery in vivo by intravenous administration and suggests the great promise of using graphene oxide in theranostic applications for treating ischemic disease.Herein we report the design and synthesis of multifunctional VEGF-loaded IR800-conjugated graphene oxide (GO-IR800-VEGF) for multi-modality imaging-monitored therapeutic angiogenesis of ischemic muscle. The as-prepared GO-IR800-VEGF positively targets VEGF receptors, maintains an elevated level of VEGF in ischemic tissues for a prolonged time, and finally leads to remarkable therapeutic angiogenesis of ischemic muscle. Although more efforts are required to further understand the in vivo behaviors and the long-term toxicology of GO, our work demonstrates the success of using GO for efficient VEGF delivery in vivo by intravenous administration and suggests the great promise of using graphene oxide in theranostic applications for treating ischemic disease. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01573d

  18. Ovarian steroids modulate leu-enkephalin levels and target leu-enkephalinergic profiles in the female hippocampal mossy fiber pathway

    PubMed Central

    Torres-Reveron, Annelyn; Khalid, Sana; Williams, Tanya J.; Waters, Elizabeth M.; Drake, Carrie T.; McEwen, Bruce S.; Milner, Teresa A.

    2008-01-01

    In the hippocampal formation (HF), the enkephalin opioids and estrogen are each known to modulate learning and cognitive performance relevant to drug abuse. Within the HF, leu-enkephalin (LENK) is most prominent in the mossy fiber (MF) pathway formed by the axons of dentate gyrus (DG) granule cells. To examine the influence of ovarian steroids on MF pathway LENK levels, we used quantitative light microscopic immunocytochemistry to evaluate LENK levels in normal cycling rats and in estrogen-treated ovariectomized rats. Rats in estrus had increased levels of LENK-immunoreactivity (ir) in the DG hilus compared to rats in diestrus or proestrus. Rats in estrus and proestrus had higher levels of LENK-ir in CA3a-c compared to rats in diestrus. Ovariectomized (OVX) rats 24 hrs (but not 6 or 72 hrs) after estradiol benzoate (EB; 10 µg) administration had increased LENK-ir in the DG hilus and CA3c. Electron microscopy showed a larger proportion of LENK-labeled small terminals and axons in the DGthe DG hilus compared to CA3 which may have contributed to region-specific changes in LENK-ir densities. Next we evaluated the subcellular relationships of estrogen receptor (ER) α, ERβ and progestin receptor (PR) with LENK-labeled MF pathway profiles using dual-labeling electron microscopy. ERβ-ir colocalized in some LENK-labeled MF terminals and smaller terminals while PR-ir was mostly in CA3 axons, some of which also showed colocalization with LENK. ERα-ir was in dendritic spines, but no colocalization with LENK-labeled profiles was observed. The present studies indicate that estrogen can modulate LENK in subregions of the MF pathway in a dose- and time- dependent manner. These effects might be triggered by direct activation of ERβ or PR in LENK-containing terminals. PMID:18691558

  19. Comparison of various advanced oxidation processes and chemical treatment methods for COD and color removal from a polyester and acetate fiber dyeing effluent.

    PubMed

    Azbar, N; Yonar, T; Kestioglu, K

    2004-04-01

    In this paper, a comparison of various advanced oxidation processes (O3, O3/UV, H2O2/UV, O3/H2O2/UV, Fe2+/H2O2) and chemical treatment methods using Al2(SO4)3.18H2O, FeCl3 and FeSO4 for the chemical oxygen demand (COD) and color removal from a polyester and acetate fiber dyeing effluent is undertaken. Advanced oxidation processes (AOPs) showed a superior performance compared to conventional chemical treatment, which maximum achievable color and COD removal for the textile effluent used in this study was 50% and 60%, respectively. Although O3/H2O2/UV combination among other AOPs methods studied in this paper was found to give the best result (99% removal for COD and 96% removal for color), use of Fe2+/H2O2 seems to show a satisfactory COD and color removal performance and to be economically more viable choice for the acetate and polyester fiber dyeing effluent on the basis of 90% removal. PMID:14720544

  20. Correlation of the structure and the luminescence properties of Eu 3+-doped Gd 2O 3 oxide between fiber single crystal and the nano-size powders

    NASA Astrophysics Data System (ADS)

    Louis, C.; Lebbou, K.; Flores-Gonzalez, M. A.; Bazzi, R.; Hautefeuille, B.; Mercier, B.; Roux, S.; Perriat, P.; Olagnon, C.; Tillement, O.

    2004-05-01

    Gd 2- xEu xO 3 powder materials doped with Eu 3+ using different concentration from x=0 to 2 were prepared by a new sol-lyophilization synthesis and fiber single crystal (Gd 2O 3-Gd 2O 3/Eu 3+) oxides were grown using laser-heated pedestal growth (LHPG) technique. X-ray powder diffraction performed at room temperature showed that the materials obtained by lyophilization technique are cubic, lies in the nanometer range and different from bulk materials. The materials are a continued solid solution and the lattice parameter a-axis increases with Eu 3+ concentration. The fibers grown by LHPG technique were single crystal, transparent, red in color when Eu 3+ concentration is high, and the structure is monoclinic for Eu 3+<15%. The luminescence of Eu 3+ from C 2 crystallographic site was been detected. In the case of nano-particles oxide, an additional peak in emission spectral is obtained at λ=610 nm. The influence of Eu 3+, particles sizes and the structure on the luminescence spectral of Eu 3+ ions was been described.

  1. Doxorubicin loaded PEG-b-poly(4-vinylbenzylphosphonate) coated magnetic iron oxide nanoparticles for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Hałupka-Bryl, Magdalena; Bednarowicz, Magdalena; Dobosz, Bernadeta; Krzyminiewski, Ryszard; Zalewski, Tomasz; Wereszczyńska, Beata; Nowaczyk, Grzegorz; Jarek, Marcin; Nagasaki, Yukio

    2015-06-01

    Due to their unique physical properties, superparamagnetic iron oxide nanoparticles are increasingly used in medical applications. They are very useful carriers for delivering antitumor drugs in targeted cancer treatment. Magnetic nanoparticles with chemiotherapeutic were synthesized by coprecipitation method followed by coating with biocompatible polymer. The aim of this work is to characterize physical and magnetic properties of synthesized nanoparicles. Characterization was carried out using EPR, HRTEM, X-ray diffraction, SQUID and NMR methods. The present findings show that synthesized nanosystem is promising tool for potential magnetic drug delivery.

  2. Continuous method of producing silicon carbide fibers

    NASA Technical Reports Server (NTRS)

    Barnard, Thomas Duncan (Inventor); Nguyen, Kimmai Thi (Inventor); Rabe, James Alan (Inventor)

    1999-01-01

    This invention pertains to a method for production of polycrystalline ceramic fibers from silicon oxycarbide (SiCO) ceramic fibers wherein the method comprises heating an amorphous ceramic fiber containing silicon and carbon in an inert environment comprising a boron oxide and carbon monoxide at a temperature sufficient to convert the amorphous ceramic fiber to a polycrystalline ceramic fiber. By having carbon monoxide present during the heating of the ceramic fiber, it is possible to achieve higher production rates on a continuous process.

  3. Mini- and full-length dystrophin gene transfer induces the recovery of nitric oxide synthase at the sarcolemma of mdx4cv skeletal muscle fibers.

    PubMed

    Decrouy, A; Renaud, J M; Lunde, J A; Dickson, G; Jasmin, B J

    1998-01-01

    In normal skeletal muscle fibers, dystrophin accumulates at the cytoplasmic face of the sarcolemma where it associates with dystrophin-associated proteins (DAPs). Several studies have recently shown that the neuronal isoform of nitric oxide synthase (nNOS) is also located at the sarcolemma, and that this membrane localization is mediated through interactions of nNOS with one of the DAPs, namely alpha 1-syntrophin. Since the lack of dystrophin in muscle fibers from Duchenne muscular dystrophy patients and mdx mice is accompanied by an absence of sarcolemmal nNOS, we examined in the present study, whether dystrophin gene replacement would lead to the restoration of nNOS at its appropriate subcellular location. To this end, tibialis anterior muscles from mdx4cv mice were directly injected with plasmid DNA encoding either full-length (pRSV-dys) or mini-(pRSV-dyB; lacking exons 17-48) dystrophin. For these experiments, we chose to study 10-week-old mdx4cv mice since at this developmental stage, muscles from these mice have already undergone several cycles of degeneration-regeneration. Immunofluorescence experiments performed on serial cross-sections revealed that approximately 50% of the dystrophin-positive fibers also exhibited significant levels of nNOS at their sarcolemma 2 weeks following gene transfer with pRSV-dys. Similar results were obtained with pRSV-dyB indicating that exons 17-48 of the dystrophin gene are not essential for the correct localization of nNOS in skeletal muscle fibers. Taken together with the recent demonstration that dystrophin gene transfer leads to significant physiological benefits our results suggest that dystrophin gene therapy using full-length or truncated dystrophin, also induces a rapid recovery of biochemical functions. PMID:9536265

  4. In vitro and in vivo brain-targeting chemo-photothermal therapy using graphene oxide conjugated with transferrin for Gliomas.

    PubMed

    Dong, Haixin; Jin, Mei; Liu, Zhiming; Xiong, Honglian; Qiu, Xuejun; Zhang, Wen; Guo, Zhouyi

    2016-08-01

    Current therapies for treating malignant glioma exhibit low therapeutic efficiency because of strong systemic side effects and poor transport across the blood brain barrier (BBB). Herein, we combined targeted chemo-photothermal glioma therapy with a novel multifunctional drug delivery system to overcome these issues. Drug carrier transferrin-conjugated PEGylated nanoscale graphene oxide (TPG) was successfully synthesized and characterized. When loaded on the proposed TPG-based drug delivery (TPGD) system, the anticancer drug doxorubicin could pass through the BBB and improve drug accumulation both in vitro and in vivo. TPGD was found to perform dual functions in chemotherapy and photothermal therapy. Targeted TPGD combination therapy showed higher rates of glioma cell death and prolonged survival of glioma-bearing rats compared with single doxorubicin or PGD therapy. In conclusion, we developed a potential nanoscale drug delivery system for combined therapy of glioma that can effectively decrease side effects and improve therapeutic effects. PMID:27189185

  5. Divergent targets of glycolysis and oxidative phosphorylation result in additive effects of metformin and starvation in colon and breast cancer.

    PubMed

    Marini, Cecilia; Bianchi, Giovanna; Buschiazzo, Ambra; Ravera, Silvia; Martella, Roberto; Bottoni, Gianluca; Petretto, Andrea; Emionite, Laura; Monteverde, Elena; Capitanio, Selene; Inglese, Elvira; Fabbi, Marina; Bongioanni, Francesca; Garaboldi, Lucia; Bruzzi, Paolo; Orengo, Anna Maria; Raffaghello, Lizzia; Sambuceti, Gianmario

    2016-01-01

    Emerging evidence demonstrates that targeting energy metabolism is a promising strategy to fight cancer. Here we show that combining metformin and short-term starvation markedly impairs metabolism and growth of colon and breast cancer. The impairment in glycolytic flux caused by starvation is enhanced by metformin through its interference with hexokinase II activity, as documented by measurement of 18F-fluorodeoxyglycose uptake. Oxidative phosphorylation is additively compromised by combined treatment: metformin virtually abolishes Complex I function; starvation determines an uncoupled status of OXPHOS and amplifies the activity of respiratory Complexes II and IV thus combining a massive ATP depletion with a significant increase in reactive oxygen species. More importantly, the combined treatment profoundly impairs cancer glucose metabolism and virtually abolishes lesion growth in experimental models of breast and colon carcinoma. Our results strongly suggest that energy metabolism is a promising target to reduce cancer progression. PMID:26794854

  6. Divergent targets of glycolysis and oxidative phosphorylation result in additive effects of metformin and starvation in colon and breast cancer

    PubMed Central

    Marini, Cecilia; Bianchi, Giovanna; Buschiazzo, Ambra; Ravera, Silvia; Martella, Roberto; Bottoni, Gianluca; Petretto, Andrea; Emionite, Laura; Monteverde, Elena; Capitanio, Selene; Inglese, Elvira; Fabbi, Marina; Bongioanni, Francesca; Garaboldi, Lucia; Bruzzi, Paolo; Orengo, Anna Maria; Raffaghello, Lizzia; Sambuceti, Gianmario

    2016-01-01

    Emerging evidence demonstrates that targeting energy metabolism is a promising strategy to fight cancer. Here we show that combining metformin and short-term starvation markedly impairs metabolism and growth of colon and breast cancer. The impairment in glycolytic flux caused by starvation is enhanced by metformin through its interference with hexokinase II activity, as documented by measurement of 18F-fluorodeoxyglycose uptake. Oxidative phosphorylation is additively compromised by combined treatment: metformin virtually abolishes Complex I function; starvation determines an uncoupled status of OXPHOS and amplifies the activity of respiratory Complexes II and IV thus combining a massive ATP depletion with a significant increase in reactive oxygen species. More importantly, the combined treatment profoundly impairs cancer glucose metabolism and virtually abolishes lesion growth in experimental models of breast and colon carcinoma. Our results strongly suggest that energy metabolism is a promising target to reduce cancer progression. PMID:26794854

  7. Targeting the oxidative stress response system of fungi with safe, redox-potent chemosensitizing agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One mode of action of the antimycotics amphotericin B (AMB) or itraconazole (ITZ) against filamentous fungi involves cellular oxidative stress response. Aspergillus fumigatus sakA', a mitogen-activated protein kinase (MAPK) gene deletion mutant in the antioxidation system, was more sensitive to AMB ...

  8. Inhibition of oxidative hemolysis in erythrocytes by mitochondria-targeted antioxidants of SkQ series.

    PubMed

    Omarova, E O; Antonenko, Y N

    2014-02-01

    In the present work we studied the effect of antioxidants of the SkQ1 family (10-(6'-plastoquinonyl)decyltriphenylphosphonium) on the oxidative hemolysis of erythrocytes induced by a lipophilic free radical initiator 2,2'-azobis(2,4-dimethylvaleronitrile) (AMVN) and a water-soluble free radical initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). SkQ1 was found to protect erythrocytes from hemolysis, 2 μM being the optimal concentration. Both the oxidized and reduced SkQ1 forms exhibited protective properties. Both forms of SkQ1 also inhibited lipid peroxidation in erythrocytes induced by the lipophilic free radical initiator AMVN as detected by accumulation of malondialdehyde. However, in the case of induction of erythrocyte oxidation by AAPH, the accumulation of malondialdehyde was not inhibited by SkQ1. In the case of AAPH-induced hemolysis, the rhodamine-containing analog SkQR1 exerted a comparable protective effect at the concentration of 0.2 μM. At higher SkQ1 and SkQR1 concentrations, the protective effect was smaller, which was attributed to the ability of these compounds to facilitate hemolysis in the absence of oxidative stress. We found that plastoquinone in the oxidized form of SkQ1 could be reduced by erythrocytes, which apparently accounted for its protective action. Thus, the protective effect of SkQ in erythrocytes, which lack mitochondria, proceeded at concentrations that are two to three orders of magnitude higher than those that were active in isolated mitochondria. PMID:24794729

  9. Selective transduction of mature DC in human skin and lymph nodes by CD80/CD86-targeted fiber-modified Adenovirus-5/3

    PubMed Central

    van de Ven, Rieneke; Lindenberg, Jelle J.; Oosterhoff, Dinja; van den Tol, M. Petrousjka; Rosalia, Rodney A.; Murakami, Miho; Everts, Maaike; Scheffer, George L.; Scheper, Rik J.; de Gruijl, Tanja D.; Curiel, David T.

    2009-01-01

    In vivo targeting of dendritic cells (DC) represents an attractive alternative to currently applied ex vivo DC-based genetic tumor vaccination protocols. Finding the optimal vector for in vivo targeting of DC is important for such strategies. We therefore tested a panel of subgroup C/B chimeric and fiber-modified adenoviruses (Ad) for their relative capacity to transduce human DC. We made use of in vitro generated Langerhans Cells (LC) as well as of ex vivo human skin and melanoma-draining lymph node (LN) derived DC. Of the tested viruses the C/B-chimeric Ad5/3 virus most efficiently transduced in vitro generated LC. In addition, Ad5/3 preferentially targeted mature myeloid DC from human skin and draining LN and transduced them at significantly higher frequencies than Ad5. In addition, Ad5/3 was more specific for mature human skin-derived CD1a+ CD83+ DC than the previously reported DC-transducing C/B-chimeric vector Ad5/35, infecting less bystander cells. It was previously reported that Ad5/3 transduced human monocyte-derived DC by binding to the B7 molecules CD80 and CD86. High-efficiency transduction of mature skin-derived DC was similarly shown to be mediated through binding to CD80/CD86 and not to interfere with subsequent T cell priming. We conclude that Ad5/3, in combination with DC-activating adjuvants, represents a promising therapeutic tool for the in vivo transduction of mature DC, and may be less likely to induce unwanted side effects such as immune tolerance through the infection of non-professional antigen-presenting cells. PMID:19816192

  10. Fiber tractography of the axonal pathways linking the basal ganglia and cerebellum in Parkinson disease: implications for targeting in deep brain stimulation

    PubMed Central

    Sweet, Jennifer A.; Walter, Benjamin L.; Gunalan, Kabilar; Chaturvedi, Ashutosh; Mcintyre, Cameron C.; Miller, Jonathan P.

    2015-01-01

    Object Stimulation of white matter pathways near targeted structures may contribute to therapeutic effects of deep brain stimulation (DBS) for patients with Parkinson disease (PD). Two tracts linking the basal ganglia and cerebellum have been described in primates: the subthalamopontocerebellar tract (SPCT) and the dentatothalamic tract (DTT). The authors used fiber tractography to evaluate white matter tracts that connect the cerebellum to the region of the basal ganglia in patients with PD who were candidates for DBS. Methods Fourteen patients with advanced PD underwent 3-T MRI, including 30-directional diffusion-weighted imaging sequences. Diffusion tensor tractography was performed using 2 regions of interest: ipsilateral subthalamic and red nuclei, and contralateral cerebellar hemisphere. Nine patients underwent subthalamic DBS, and the course of each tract was observed relative to the location of the most effective stimulation contact and the volume of tissue activated. Results In all patients 2 distinct tracts were identified that corresponded closely to the described anatomical features of the SPCT and DTT, respectively. The mean overall distance from the active contact to the DTT was 2.18 ± 0.35 mm, and the mean proportional distance relative to the volume of tissue activated was 1.35 ± 0.48. There was a nonsignificant trend toward better postoperative tremor control in patients with electrodes closer to the DTT. Conclusions The SPCT and the DTT may be related to the expression of symptoms in PD, and this may have implications for DBS targeting. The use of tractography to identify the DTT might assist with DBS targeting in the future. PMID:24484226

  11. Targeted Delivery of Docetaxel by Use of Transferrin/Poly(allylamine hydrochloride)-functionalized Graphene Oxide Nanocarrier.

    PubMed

    Nasrollahi, Fatemeh; Varshosaz, Jaleh; Khodadadi, Abbas Ali; Lim, Sierin; Jahanian-Najafabadi, Ali

    2016-06-01

    The exceptional chemical and physical properties of graphene oxide (GO) make it an attractive nanomaterial for biomedical applications, particularly in drug delivery. In this work we synthesized a novel, GO-based nanocarrier for the delivery of docetaxel (DTX), a potent hydrophobic chemotherapy drug. The GO was functionalized with transferrin (Tf)-poly(allylamine hydrochloride) (PAH), which provided targeted and specific accumulation to extracellular Tf receptors and stabilized GO in physiological solutions. Tf was conjugated to PAH via amide covalent linkages, and Tf-PAH coated the surface of DTX-loaded GO through electrostatic interactions. The morphology and structure of the resulting nanostructure, along with its surface modifications, were verified by use of Fourier transform infrared (FT-IR) and UV-vis spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). DTX was loaded at a relatively high loading capacity of 37% and released in a pH-dependent and sustained manner under physiological conditions. The targeting efficiency and cytotoxicity of this drug delivery system were evaluated on MCF-7 breast cancer cells. Improved efficacy of targeted DTX-loaded nanocarrier was observed compared to nontargeted carrier and free DTX, especially at high drug concentrations. The Tf-PAH-functionalized GO nanocarrier is a promising candidate for targeted delivery and controlled release of DTX. PMID:27158834

  12. An aptamer-targeting photoresponsive drug delivery system using "off-on" graphene oxide wrapped mesoporous silica nanoparticles.

    PubMed

    Tang, Yuxia; Hu, Hao; Zhang, Molly Gu; Song, Jibin; Nie, Liming; Wang, Shouju; Niu, Gang; Huang, Peng; Lu, Guangming; Chen, Xiaoyuan

    2015-04-14

    We have developed a novel aptamer-targeting photoresponsive drug delivery system by non-covalent assembly of a Cy5.5-AS1411 aptamer conjugate on the surface of graphene oxide wrapped doxorubicin (Dox)-loaded mesoporous silica nanoparticles (MSN-Dox@GO-Apt) for light-mediated drug release and aptamer-targeted cancer therapy. The two "off-on" switches of the MSN-Dox@GO-Apt were controlled by aptamer targeting and light triggering, respectively. The Cy5.5-AS1411 ligand provides MSN-Dox@GO-Apt with nucleolin specific targeting and real-time indicator abilities by "off-on" Cy5.5 fluorescence recovery. The GO acts as a gatekeeper to prevent the loaded Dox from leaking in the absence of laser irradiation, and to control the Dox release in response to laser irradiation. When the GO wrapping falls off upon laser irradiation, the "off-on" photoresponsive drug delivery system is activated, thus inducing chemotherapy. Interestingly, with an increase in laser power, the synergism of chemotherapy and photothermal therapy in a single MSN-Dox@GO-Apt platform led to much more effective cancer cell killing than monotherapies, providing a new approach for treatment against cancer. PMID:25782595

  13. Protective efficacy of mitochondrial targeted antioxidant MitoQ against dichlorvos induced oxidative stress and cell death in rat brain.

    PubMed

    Wani, Willayat Yousuf; Gudup, Satish; Sunkaria, Aditya; Bal, Amanjit; Singh, Parvinder Pal; Kandimalla, Ramesh J L; Sharma, Deep Raj; Gill, Kiran Dip

    2011-12-01

    Dichlorvos is a synthetic insecticide that belongs to the family of chemically related organophosphate (OP) pesticides. It can be released into the environment as a major degradation product of other OPs, such as trichlorfon, naled, and metrifonate. Dichlorvos exerts its toxic effects in humans and animals by inhibiting neural acetylcholinesterase. Chronic low-level exposure to dichlorvos has been shown to result in inhibition of the mitochondrial complex I and cytochrome oxidase in rat brain, resulting in generation of reactive oxygen species (ROS). Enhanced ROS production leads to disruption of cellular antioxidant defense systems and release of cytochrome c (cyt c) from mitochondria to cytosol resulting in apoptotic cell death. MitoQ is an antioxidant, selectively targeted to mitochondria and protects it from oxidative damage and has been shown to decrease mitochondrial damage in various animal models of oxidative stress. We hypothesized that if oxidative damage to mitochondria does play a significant role in dichlorvos induced neurodegeneration, then MitoQ should ameliorate neuronal apoptosis. Administration of MitoQ (100 μmol/kg body wt/day) reduced dichlorvos (6 mg/kg body wt/day) induced oxidative stress (decreased ROS production, increased MnSOD activity and glutathione levels) with decreased lipid peroxidation, protein and DNA oxidation. In addition, MitoQ also suppressed DNA fragmentation, cyt c release and caspase-3 activity in dichlorvos treated rats compared to the control group. Further electron microscopic studies revealed that MitoQ attenuates dichlorvos induced mitochondrial swelling, loss of cristae and chromatin condensation. These results indicate that MitoQ may be beneficial against OP (dichlorvos) induced neurodegeneration. PMID:21784090

  14. Cranial sensory ganglia neurons require intrinsic N-cadherin function for guidance of afferent fibers to their final targets

    PubMed Central

    LaMora, Angela; Voigt, Mark M.

    2009-01-01

    Cell adhesion molecules, such as N-cadherin (cdh2), are essential for normal neuronal development, and as such have been implicated in an array of processes including neuronal differentiation and migration, and axon growth and fasciculation. Cdh2 is expressed in neurons of the peripheral nervous system during development, but its role in these cells during this time is poorly understood. Using the transgenic zebrafish line, tg(p2xr3.2:eGFPsl1), we have examined the involvement of cdh2 in the formation of sensory circuits by the peripheral nervous system. The tg(p2xr3.2:eGFPsl1) fish allows visualization of neurons comprising gV, gVII, gIX and gX and their axons throughout development. Reduction of cdh2 in this line was achieved by either crosses to the cdh2-mutant strain, glass onion (glo) or injection of a cdh2 morpholino (MO) into single-cell embryos. Here we show that cdh2 function is required to alter the directional vectors of growing axons upon reaching intermediate targets. The central axons enter the hindbrain appropriately but fail to turn caudally towards their final targets. Similarly, the peripheral axons extend ventrally, but fail to turn and project along a rostral/caudal axis. Furthermore, by expressing dominant negative cdh2 constructs selectively within cranial sensory ganglia (CSG) neurons, we found that cdh2 function is necessary within the axons to elicit these stereotypic turns, thus demonstrating that cdh2 acts cell autonomously. Together, our in vivo data reveal a novel role for cdh2 in the establishment of circuits by peripheral sensory neurons. PMID:19356698

  15. Asbestos-induced endothelial cell activation and injury. Demonstration of fiber phagocytosis and oxidant-dependent toxicity.

    PubMed

    Garcia, J G; Gray, L D; Dodson, R F; Callahan, K S

    1988-10-01

    Vascular endothelial cell injury is important in the development of a variety of chronic interstitial lung disorders. However, the involvement of such injury in the inflammatory response associated with the inhalation of asbestos fibers is unclear and the mechanism of asbestos fiber cytotoxicity remains unknown. In the present study, human umbilical vein endothelial cells were challenged with amosite asbestos and several parameters of cellular function were examined. Electron microscopic examination revealed that endothelial cell exposure to asbestos resulted in active phagocytosis of these particulates. Biochemical evidence of dose-dependent asbestos-mediated endothelial cell activation was indicated by increased metabolism of arachidonic acid. For example, amosite asbestos (500 micrograms/ml) produced a ninefold increase in prostacyclin (PGI2) levels over those levels in non-exposed cells. Incubation of human endothelial cells with asbestos fibers induced specific 51Cr release in both a dose- and time-dependent fashion indicative of cellular injury. Injury induced by amosite asbestos was not significantly attenuated by treatment of the endothelial cell monolayer with either the iron chelator deferoxamine, which prevents hydroxyl radical (.OH) formation, or by the superoxide anion (O2-) scavenger, superoxide dismutase. However, significant dose-dependent protection was observed with the hydrogen peroxide (H2O2) scavenger, catalase. Chelation of elemental iron present within amosite asbestos fibers by deferoxamine produced a 33% reduction in asbestos cytotoxicity, suggesting a potential role for hydroxyl radical-mediated injury via the iron-catalyzed Haber-Weiss reaction.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3202471

  16. Targeting tumor hypoxia with the epigenetic anticancer agent, RRx-001: a superagonist of nitric oxide generation.

    PubMed

    Fens, Marcel H; Cabrales, Pedro; Scicinski, Jan; Larkin, Sandra K; Suh, Jung H; Kuypers, Frans A; Oronsky, Neil; Lybeck, Michelle; Oronsky, Arnold; Oronsky, Bryan

    2016-08-01

    This study reveals a novel interaction between deoxyhemoglobin, nitrite and the non-toxic compound, RRx-001, to generate supraphysiologic levels of nitric oxide (NO) in blood. We characterize the nitrite reductase activity of deoxyhemoglobin, which in the presence of bound RRx-001 reduces nitrite at a much faster rate, leading to markedly increased NO generation. These data expand on the paradigm that hemoglobin generates NO via nitrite reduction during hypoxia and ischemia when nitric oxide synthase (NOS) function is limited. Here, we demonstrate that RRx-001 greatly enhances NO generation from nitrite reduction. RRx-001 is thus the first example of a functional superagonist for nitrite reductase. We hypothesize that physiologically this reaction releases the potentially cytotoxic effector NO selectively in hypoxic tumor regions. It may be that a binary NO-H2O2 trigger is indirectly responsible for the observed tumoricidal activity of RRx-001 since NO is known to inhibit mitochondrial respiration. PMID:27377482

  17. The impact of oxidative stress in thiamine deficiency: a multifactorial targeting issue.

    PubMed

    Hazell, Alan S; Faim, Samantha; Wertheimer, Guilherme; Silva, Vinicius R; Marques, Cleiton S

    2013-04-01

    Thiamine (vitamin B1) deficiency, the underlying cause of Wernicke-Korsakoff syndrome, is associated with the development of focal neuronal loss in vulnerable areas of the brain. Although the actual mechanism(s) that lead to the selective histological lesions characteristic of this disorder remain unresolved, oxidative stress has been shown to play a major role in its pathophysiology. In this review, the multifactorial influence of oxidative stress on a variety of processes known to take part in the development of structural lesions in TD including excitotoxicity, neuroinflammation, blood-brain barrier integrity, mitochondrial integrity, apoptosis, nucleic acid function, and neural stem cells will be discussed, and therapeutic strategies undertaken for treating neurodegeneration examined which may have an impact on the future treatment of this important vitamin deficiency. PMID:23333339

  18. Fabrication of self-supported oxide targets by cationic adsorption in cellulosic membranes and thermal decomposition

    SciTech Connect

    Quinby, T.C.

    1983-01-01

    Techniques for producing relatively durable oxide films of various elements will be described. Areal densities of films produced to date have ranged from 150 ..mu..g/cm/sup 2/ to 2.5 mg/cm/sup 2/, and are virtually transparent. Films produced by this technique were weighed directly and mounted on frames. General parameters for use of this technique will be described.

  19. Polymeric nanocomposites loaded with fluoridated hydroxyapatite Ln3+ (Ln = Eu or Tb)/iron oxide for magnetic targeted cellular imaging

    PubMed Central

    Pan, Jie; Liu, Wei-Jiao; Hua, Chao; Wang, Li-Li; Wan, Dong; Gong, Jun-Bo

    2015-01-01

    Objective To fabricate polymeric nanocomposites with excellent photoluminescence, magnetic properties, and stability in aqueous solutions, in order to improve specificity and sensitivity of cellular imaging under a magnetic field. Methods Fluoridated Ln3+-doped HAP (Ln3+-HAP) NPs and iron oxides (IOs) can be encapsulated with biocompatible polymers via a modified solvent exaction/evaporation technique to prepare polymeric nanocomposites with fluoridated Ln3+-HAP/iron oxide. The nanocomposites were characterized for surface morphology, fluorescence spectra, magnetic properties and in vitro cytotoxicity. Magnetic targeted cellular imaging of such nanocomposites was also evaluated with confocal laser scanning microscope using A549 cells with or without magnetic field. Results The fabricated nanocomposites showed good stability and excellent luminescent properties, as well as low in vitro cytotoxicity, indicating that the nanocomposites are suitable for biological applications. Nanocomposites under magnetic field achieved much higher cellular uptake via an energy-dependent pathway than those without magnetic field. Conclusion The nanocomposites fabricated in this study will be a promising tool for magnetic targeted cellular imaging with improved specificity and enhanced selection. PMID:26487962

  20. Protein Phosphatase 2A Holoenzyme Is Targeted to Peroxisomes by Piggybacking and Positively Affects Peroxisomal β-Oxidation1[OPEN

    PubMed Central

    Kataya, Amr R.A.; Heidari, Behzad; Hagen, Lars; Kommedal, Roald; Slupphaug, Geir; Lillo, Cathrine

    2015-01-01

    The eukaryotic, highly conserved serine (Ser)/threonine-specific protein phosphatase 2A (PP2A) functions as a heterotrimeric complex composed of a catalytic (C), scaffolding (A), and regulatory (B) subunit. In Arabidopsis (Arabidopsis thaliana), five, three, and 17 genes encode different C, A, and B subunits, respectively. We previously found that a B subunit, B′θ, localized to peroxisomes due to its C-terminal targeting signal Ser-Ser-leucine. This work shows that PP2A C2, C5, andA2 subunits interact and colocalize with B′θ in peroxisomes. C and A subunits lack peroxisomal targeting signals, and their peroxisomal import depends on B′θ and appears to occur by piggybacking transport. B′θ knockout mutants were impaired in peroxisomal β-oxidation as shown by developmental arrest of seedlings germinated without sucrose, accumulation of eicosenoic acid, and resistance to protoauxins indole-butyric acid and 2,4-dichlorophenoxybutyric acid. All of these observations strongly substantiate that a full PP2A complex is present in peroxisomes and positively affects β-oxidation of fatty acids and protoauxins. PMID:25489022

  1. Interaction of periodate-oxidized target cells and cytolytic T lymphocytes: a model system of "polyclonal MHC recognition".

    PubMed

    Keren, Z; Berke, G

    1986-09-01

    In oxidation-dependent cytotoxicity (ODCC), cytolytic T lymphocytes (CTL) non-specifically recognize, bind to and lyse oxidized target cells (O-TC) but the precise mechanism whereby CTL react with O-TC is far from clear (Berke, G., Immunol. Rev. 1983. 72:5). Here we present evidence that CTL/O-TC interactions are blocked by aldehyde-reactive reagents such as hydroxylamine, adipic acid dihydrazide and thiocarbohydrazide and that preformed CTL/O-TC conjugates dissociate upon reduction with NaBH4, suggesting that active aldehyde groups of O-TC rather than intercellular Schiff bases are involved in the recognition and lysis of O-TC by CTL in ODCC. The aldehydes are bound to trypsin-sensitive, non-H-2 glycoproteins that appear to be different and unique in the three different target cell lines so far examined (EL4, L1210, R1.1). In view of these and previous findings we would like to suggest that in ODCC, active aldehydes react with adjacent major histocompatibility complex and perhaps other cell-surface molecules to create a multitude of modified conformations, responsible for the "polyclonal" (nonspecific) MHC recognition and lysis of O-TC by CTL, as well as for an altered pattern of H-2 antibody binding to O-TC. PMID:3019706

  2. Genome-wide Bisulfite Sequencing in Zygotes Identifies Demethylation Targets and Maps the Contribution of TET3 Oxidation

    PubMed Central

    Peat, Julian R.; Dean, Wendy; Clark, Stephen J.; Krueger, Felix; Smallwood, Sébastien A.; Ficz, Gabriella; Kim, Jong Kyoung; Marioni, John C.; Hore, Timothy A.; Reik, Wolf

    2014-01-01

    Summary Fertilization triggers global erasure of paternal 5-methylcytosine as part of epigenetic reprogramming during the transition from gametic specialization to totipotency. This involves oxidation by TET3, but our understanding of its targets and the wider context of demethylation is limited to a small fraction of the genome. We employed an optimized bisulfite strategy to generate genome-wide methylation profiles of control and TET3-deficient zygotes, using SNPs to access paternal alleles. This revealed that in addition to pervasive removal from intergenic sequences and most retrotransposons, gene bodies constitute a major target of zygotic demethylation. Methylation loss is associated with zygotic genome activation and at gene bodies is also linked to increased transcriptional noise in early development. Our data map the primary contribution of oxidative demethylation to a subset of gene bodies and intergenic sequences and implicate redundant pathways at many loci. Unexpectedly, we demonstrate that TET3 activity also protects certain CpG islands against methylation buildup. PMID:25497087

  3. Characterization of Iron-Oxide Loaded Adult Stem Cells for Magnetic Particle Imaging in Targeted Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Lüdtke-Buzug, Kerstin; Rapoport, Daniel Hans; Schneider, Dagmar

    2010-12-01

    Recently, magnetic particle imaging (MPI) has been presented as a new method for the measurement of the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). MPI is based on the nonlinear magnetization response of nanoparticles that are subjected to a sinusoidal magnetic field. Spatial resolution and signal to noise ratio of MPI depend on the particle quality. This is particularly important when stem cells shall be tracked with MPI. Stem cell-based treatment is an upcoming technology in targeted cancer-therapy. In this study, we analyzed the particle quality of newly developed dextran-coated SPIONs—with respect to their response in the imaging experiment—using magnetic particle spectrometry. The uptake of dextran-coated SPIONs into rat and human adult stem cells was monitored via transmission electron microscopy. Furthermore, adult stem cells were incubated with FITC-dextran-coated SPIONs and stained for confocal laser scanning microscopy. The dextran- and FITC-dextran coated SPIONs were localized in the cytoplasm of rat and human adult stem cells. MPI promises real-time imaging with high spatial resolution at high sensitivity. Our data support iron oxide loaded adult stem cells as a powerful tool for targeted cancer therapy.

  4. Oxidative Stress Is a Central Target for Physical Exercise Neuroprotection Against Pathological Brain Aging.

    PubMed

    García-Mesa, Yoelvis; Colie, Sandra; Corpas, Rubén; Cristòfol, Rosa; Comellas, Francesc; Nebreda, Angel R; Giménez-Llort, Lydia; Sanfeliu, Coral

    2016-01-01

    Physical exercise is suggested for preventing or delaying senescence and Alzheimer's disease (AD). We have examined its therapeutic value in the advanced stage of AD-like pathology in 3xTg-AD female mice through voluntary wheel running from 12 to 15 months of age. Mice submitted to exercise showed improved body fitness, immunorejuvenation, improvement of behavior and cognition, and reduced amyloid and tau pathology. Brain tissue analysis of aged 3xTg-AD mice showed high levels of oxidative damage. However, this damage was decreased by physical exercise through regulation of redox homeostasis. Network analyses showed that oxidative stress was a central event, which correlated with AD-like pathology and the AD-related behaviors of anxiety, apathy, and cognitive loss. This study corroborates the importance of redox mechanisms in the neuroprotective effect of physical exercise, and supports the theory of the crucial role of oxidative stress in the switch from normal brain aging to pathological aging and AD. PMID:25720862

  5. Silibinin attenuates methotrexate-induced pulmonary injury by targeting oxidative stress

    PubMed Central

    KALEMCI, SERDAR; TOPAL, YASAR; CELIK, SERKAN YASAR; YILMAZ, NIGAR; BEYDILLI, HALIL; KOSAR, MEHMET ILKAY; DIRICAN, NIGAR; ALTUNTAS, IRFAN

    2015-01-01

    The aim of the present study was to assess the protective effect of silibinin against methotrexate (MTX)-induced pulmonary toxicity. Rats were divided into four groups (MTX, MTX + silibinin, silibinin and control. MTX was injected intraperitoneally (i.p) into female Wistar rats (10 mg/kg/day for 3 days), which resulted in significant increases in the serum levels of alanine aminotransferase, aspartate aminotransferase and oxidant enzymes, including nitric oxide and myeloperoxidase. Furthermore, significant reductions were detected in the serum activity levels of the antioxidative enzymes, glutathione peroxidase and superoxide dismutase, when compared with the control group. However, administration of silibinin (100 mg/kg/day for 10 days, i.p.) was shown to ameliorate the MTX-induced pulmonary toxicity, as indicated by the normalization of the oxidative stress parameters. Furthermore, silibinin treatment was demonstrated to reduce the histopathological changes associated with MTX. In conclusion, silibinin exhibited protective effects against MTX-induced pulmonary toxicity, which may be attributed to its antioxidant activity. PMID:26622344

  6. Chronic bladder ischemia and oxidative stress: new pharmacotherapeutic targets for lower urinary tract symptoms.

    PubMed

    Nomiya, Masanori; Andersson, Karl-Erik; Yamaguchi, Osamu

    2015-01-01

    Chronic bladder ischemia is potentially a common cause of lower urinary tract symptoms in the elderly. Epidemiological studies have shown a close association between lower urinary tract symptoms and vascular risk factors for atherosclerosis, and investigations using transrectal color Doppler ultrasonography have shown a negative correlation between decreased lower urinary tract perfusion and International Prostate Symptom Score in elderly patients with lower urinary tract symptoms. Bladder blood flow is also known to decrease in men with bladder outlet obstruction as a result of benign prostatic hyperplasia. Studies in animal models suggest that chronic bladder ischemia and repeated ischemia/reperfusion during a micturition cycle might produce oxidative stress, leading to denervation of the bladder and the expression of tissue-damaging molecules in the bladder wall, which could be responsible for the development of bladder hyperactivity progressing to bladder underactivity. The effects of drugs with different mechanisms of action; for example, α1-adrenoceptor antagonists, phosphodiesterase type 5 inhibitors, free radical scavengers and β3-adrenoceptor agonist, have been studied in animal models of chronic bladder ischemia. The drugs, representing different treatment principles for increasing blood flow and decreasing oxidative stress, showed protective effects not only on urodynamic parameters, but also on negative effects on muscle contractility and on detrimental structural bladder wall changes. Improvement of lower urinary tract perfusion and control of oxidative stress can be considered new therapeutic strategies for treatment of bladder dysfunction induced by chronic ischemia. PMID:25339506

  7. Cerebral Small Vessel Disease: Targeting Oxidative Stress as a Novel Therapeutic Strategy?

    PubMed Central

    De Silva, T. Michael; Miller, Alyson A.

    2016-01-01

    Cerebral small vessel disease (SVD) is a major contributor to stroke, and a leading cause of cognitive impairment and dementia. Despite the devastating effects of cerebral SVD, the pathogenesis of cerebral SVD is still not completely understood. Moreover, there are no specific pharmacological strategies for its prevention or treatment. Cerebral SVD is characterized by marked functional and structural abnormalities of the cerebral microcirculation. The clinical manifestations of these pathological changes include lacunar infarcts, white matter hyperintensities, and cerebral microbleeds. The main purpose of this review is to discuss evidence implicating oxidative stress in the arteriopathy of both non-amyloid and amyloid (cerebral amyloid angiopathy) forms of cerebral SVD and its most important risk factors (hypertension and aging), as well as its contribution to cerebral SVD-related brain injury and cognitive impairment. We also highlight current evidence of the involvement of the NADPH oxidases in the development of oxidative stress, enzymes that are a major source of reactive oxygen species in the cerebral vasculature. Lastly, we discuss potential pharmacological strategies for oxidative stress in cerebral SVD, including some of the historical and emerging NADPH oxidase inhibitors. PMID:27014073

  8. Facing-target mid-frequency magnetron reactive sputtered hafnium oxide film: Morphology and electrical properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Xu, Jun; Wang, You-Nian; Choi, Chi Kyu; Zhou, Da-Yu

    2016-03-01

    Amorphous hafnium dioxide (HfO2) film was prepared on Si (100) by facing-target mid-frequency reactive magnetron sputtering under different oxygen/argon gas ratio at room temperature with high purity Hf target. 3D surface profiler results showed that the deposition rates of HfO2 thin film under different O2/Ar gas ratio remain unchanged, indicating that the facing target midfrequency magnetron sputtering system provides effective approach to eliminate target poisoning phenomenon which is generally occurred in reactive sputtering procedure. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) demonstrated that the gradual reduction of oxygen vacancy concentration and the densification of deposited film structure with the increase of oxygen/argon (O2/Ar) gas flow ratio. Atomic force microscopy (AFM) analysis suggested that the surface of the as-deposited HfO2 thin film tends to be smoother, the root-meansquare roughness (RMS) reduced from 0.876 nm to 0.333 nm while O2/Ar gas flow ratio increased from 1/4 to 1/1. Current-Voltage measurements of MOS capacitor based on Au/HfO2/Si structure indicated that the leakage current density of HfO2 thin films decreased by increasing of oxygen partial pressure, which resulted in the variations of pore size and oxygen vacancy concentration in deposited thin films. Based on the above characterization results the leakage current mechanism for all samples was discussed systematically.

  9. Photo-controlled targeted intracellular delivery of both nitric oxide and singlet oxygen using a fluorescence-trackable ruthenium nitrosyl functional nanoplatform.

    PubMed

    Xiang, Hui-Jing; An, Lu; Tang, Wei-Wei; Yang, Shi-Ping; Liu, Jin-Gang

    2015-02-14

    A multifunctional nitric oxide (NO) delivery nanoplatform that combines functionalities of target directing, fluorescence tracking, and photo-controlled target attacking was developed. The {Ru-NO@TiO2 NPs} nanoplatform selectively targeted folate-receptor over-expressed cancer cells while being simultaneously traced based on its inherent fluorescence. Intracellular localized NO and singlet oxygen were produced on demand by controlled visible light illumination, producing a synergistic cytotoxic effect to cancer cells. PMID:25567668

  10. Imaging of oxidation-specific epitopes with targeted nanoparticles to detect high-risk atherosclerotic lesions: progress and future directions.

    PubMed

    Briley-Saebo, Karen; Yeang, Calvin; Witztum, Joseph L; Tsimikas, Sotirios

    2014-11-01

    Oxidation-specific epitopes (OSE) within developing atherosclerotic lesions are key antigens that drive innate and adaptive immune responses in atherosclerosis, leading to chronic inflammation. Oxidized phospholipids and malondialdehyde-lysine epitopes are well-characterized OSE present in human atherosclerotic lesions, particularly in pathologically defined vulnerable plaques. Using murine and human OSE-specific antibodies as targeting agents, we have developed radionuclide and magnetic resonance based nanoparticles, containing gadolinium, manganese or lipid-coated ultrasmall superparamagnetic iron oxide, to non-invasively image OSE within experimental atherosclerotic lesions. These methods quantitate plaque burden, allow detection of lesion progression and regression, plaque stabilization, and accumulation of OSE within macrophage-rich areas of the artery wall, suggesting they detect the most active lesions. Future studies will focus on using "natural" antibodies, lipopeptides, and mimotopes for imaging applications. These approaches should enhance the clinical translation of this technique to image, monitor, evaluate efficacy of novel therapeutic agents, and guide optimal therapy of high-risk atherosclerotic lesions. PMID:25297940

  11. Ultrasmall cationic superparamagnetic iron oxide nanoparticles as nontoxic and efficient MRI contrast agent and magnetic-targeting tool.

    PubMed

    Uchiyama, Mayara Klimuk; Toma, Sergio Hiroshi; Rodrigues, Stephen Fernandes de Paula; Shimada, Ana Lucia Borges; Loiola, Rodrigo Azevedo; Cervantes Rodríguez, Hernán Joel; Oliveira, Pedro Vitoriano; Luz, Maciel Santos; Rabbani, Said Rahnamaye; Toma, Henrique Eisi; Poliselli Farsky, Sandra Helena; Araki, Koiti

    2015-01-01

    Fully dispersible, cationic ultrasmall (7 nm diameter) superparamagnetic iron oxide nanoparticles, exhibiting high relaxivity (178 mM(-1)s(-1) in 0.47 T) and no acute or subchronic toxicity in Wistar rats, were studied and their suitability as contrast agents for magnetic resonance imaging and material for development of new diagnostic and treatment tools demonstrated. After intravenous injection (10 mg/kg body weight), they circulated throughout the vascular system causing no microhemorrhage or thrombus, neither inflammatory processes at the mesentery vascular bed and hepatic sinusoids (leukocyte rolling, adhesion, or migration as evaluated by intravital microscopy), but having been spontaneously concentrated in the liver, spleen, and kidneys, they caused strong negative contrast. The nanoparticles are cleared from kidneys and bladder in few days, whereas the complete elimination from liver and spleen occurred only after 4 weeks. Ex vivo studies demonstrated that cationic ultrasmall superparamagnetic iron oxide nanoparticles caused no effects on hepatic and renal enzymes dosage as well as on leukocyte count. In addition, they were readily concentrated in rat thigh by a magnet showing its potential as magnetically targeted carriers of therapeutic and diagnostic agents. Summarizing, cationic ultrasmall superparamagnetic iron oxide nanoparticles are nontoxic and efficient magnetic resonance imaging contrast agents useful as platform for the development of new materials for application in theranostics. PMID:26251595

  12. Ultrasmall cationic superparamagnetic iron oxide nanoparticles as nontoxic and efficient MRI contrast agent and magnetic-targeting tool

    PubMed Central

    Uchiyama, Mayara Klimuk; Toma, Sergio Hiroshi; Rodrigues, Stephen Fernandes; Shimada, Ana Lucia Borges; Loiola, Rodrigo Azevedo; Cervantes Rodríguez, Hernán Joel; Oliveira, Pedro Vitoriano; Luz, Maciel Santos; Rabbani, Said Rahnamaye; Toma, Henrique Eisi; Poliselli Farsky, Sandra Helena; Araki, Koiti

    2015-01-01

    Fully dispersible, cationic ultrasmall (7 nm diameter) superparamagnetic iron oxide nanoparticles, exhibiting high relaxivity (178 mM−1s−1 in 0.47 T) and no acute or subchronic toxicity in Wistar rats, were studied and their suitability as contrast agents for magnetic resonance imaging and material for development of new diagnostic and treatment tools demonstrated. After intravenous injection (10 mg/kg body weight), they circulated throughout the vascular system causing no microhemorrhage or thrombus, neither inflammatory processes at the mesentery vascular bed and hepatic sinusoids (leukocyte rolling, adhesion, or migration as evaluated by intravital microscopy), but having been spontaneously concentrated in the liver, spleen, and kidneys, they caused strong negative contrast. The nanoparticles are cleared from kidneys and bladder in few days, whereas the complete elimination from liver and spleen occurred only after 4 weeks. Ex vivo studies demonstrated that cationic ultrasmall superparamagnetic iron oxide nanoparticles caused no effects on hepatic and renal enzymes dosage as well as on leukocyte count. In addition, they were readily concentrated in rat thigh by a magnet showing its potential as magnetically targeted carriers of therapeutic and diagnostic agents. Summarizing, cationic ultrasmall superparamagnetic iron oxide nanoparticles are nontoxic and efficient magnetic resonance imaging contrast agents useful as platform for the development of new materials for application in theranostics. PMID:26251595

  13. Facile synthesis and magnetic property of iron oxide/MCM-41 mesoporous silica nanospheres for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Yu, Le-Le; Bi, Hong

    2012-04-01

    Iron oxide/MCM-41 hybrid nanospheres (designated as MMSN) with a large surface area of 1334 m2/g and a uniform diameter of 85 nm have been synthesized via a facile sol-gel route. Transmission electron microscopy (TEM) imagery shows many ultra-small iron oxide nanoparticles evenly distributed inside the mesoporous silica nanospheres. High-resolution TEM image with a corresponding electron diffraction spectrum and Fourier transform infrared spectra confirm the formation of iron oxide nanoparticles while the ordered mesoporous silica structure is maintained. The MMSN present a ferromagnetic property that ensures them a fast response to an applied magnetic field. Moreover, they are proven to be beneficial for loading an anticancer drug—doxorubicin hydrochloride (DOX), because a considerable loading content of 6.0% and a high entrapment efficiency of 90.5% have been achieved. Most notably, these DOX-loaded MMSN display not only a pH-variable but also a magnetic field-controllable drug release behavior. Further, after 48 h co-incubation, the MMSN did not show any significant cytotoxicity against human HepG2 cells even at a high concentration of 250 μg/mL. These results have demonstrated that the prepared MMSN may be potential drug carriers for both magnetic targeting and stimuli-responsive controlled release.

  14. Imaging of oxidation-specific epitopes with targeted nanoparticles to detect high-risk atherosclerotic lesions: Progress and future directions

    PubMed Central

    Briley-Saebo, Karen; Yeang, Calvin; Witztum, Joseph L.; Tsimikas, Sotirios

    2014-01-01

    Oxidation-specific epitopes (OSE) within developing atherosclerotic lesions are key antigens that drive innate and adaptive immune responses in atherosclerosis, leading to chronic inflammation. Oxidized phospholipids and malondialdehyde-lysine epitopes are well-characterized OSE present in human atherosclerotic lesions, particularly in pathologically defined vulnerable plaques. Using murine and human OSE-specific antibodies as targeting agents, we have developed radionuclide and magnetic resonance based nanoparticles, containing gadolinium, manganese or lipid-coated ultrasmall superparamagnetic iron oxide, to noninvasively image OSE within experimental atherosclerotic lesions. These methods quantitate plaque burden, allow detection of lesion progression and regression, plaque stabilization, and accumulation of OSE within macrophage-rich areas of the artery wall, suggesting they detect the most active lesions. Future studies will focus on using “natural” antibodies, lipopeptides and mimotopes for imaging applications. These approaches should enhance the clinical translation of this technique to image, monitor, evaluate efficacy of novel therapeutic agents and guide optimal therapy of high-risk atherosclerotic lesions. PMID:25297940

  15. Methods of producing continuous boron carbide fibers

    SciTech Connect

    Garnier, John E.; Griffith, George W.

    2015-12-01

    Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

  16. Arsenite Targets the Zinc Finger Domains of Tet Proteins and Inhibits Tet-Mediated Oxidation of 5-Methylcytosine.

    PubMed

    Liu, Shuo; Jiang, Ji; Li, Lin; Amato, Nicholas J; Wang, Zi; Wang, Yinsheng

    2015-10-01

    Arsenic toxicity is a serious public health problem worldwide that brings more than 100 million people into the risk of arsenic exposure from groundwater and food contamination. Although there is accumulating evidence linking arsenic exposure with aberrant cytosine methylation in the global genome or at specific genomic loci, very few have investigated the impact of arsenic on the oxidation of 5-methylcytosine (5-mC) mediated by the Ten-eleven translocation (Tet) family of proteins. Owing to the high binding affinity of As(III) toward cysteine residues, we reasoned that the highly conserved C3H-type zinc fingers situated in Tet proteins may constitute potential targets for arsenic binding. Herein, we found that arsenite could bind directly to the zinc fingers of Tet proteins in vitro and in cells, and this interaction substantially impaired the catalytic efficiency of Tet proteins in oxidizing 5-mC to 5-hydroxymethylcytosine (5-hmC), 5-formylcytosine (5-foC), and 5-carboxylcytosine (5-caC). Treatments with arsenite also led to a dose-dependent decrease in the level of 5-hmC, but not 5-mC, in DNA isolated from HEK293T cells overexpressing the catalytic domain of any of the three Tet proteins and from mouse embryonic stem cells. Together, our study unveiled, for the first time, that arsenite could alter epigenetic signaling by targeting the zinc fingers of Tet proteins and perturbing the Tet-mediated oxidation of 5-mC in vitro and in cells. Our results offer important mechanistic understanding of arsenic epigenotoxicity and carcinogenesis in mammalian systems and may lead to novel approaches for the chemoprevention of arsenic toxicity. PMID:26355596

  17. High strength high modulus ceramic fiber

    NASA Technical Reports Server (NTRS)

    Fetterolf, R. N.

    1972-01-01

    Low cost method was developed for producing high strength, high modulus, continuous ceramic oxide fibers. Process transforms inexpensive metallic salts into syrup-like liquids that can be fiberized at room temperatures. Resulting salt fibers are then converted to oxides by calcination at relatively low temperatures.

  18. Fiber optic detector

    NASA Astrophysics Data System (ADS)

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1990-04-01

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  19. Fiber optic detector

    SciTech Connect

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  20. Photoresponsive fluorescent reduced graphene oxide by spiropyran conjugated hyaluronic acid for in vivo imaging and target delivery.

    PubMed

    Nahain, Abdullah-Al; Lee, Jung-Eun; Jeong, Ji Hoon; Park, Sung Young

    2013-11-11

    This present article demonstrates the strategy to prepare photoresponsive reduced graphene oxide with mussel inspired adhesive material dopamine (DN) and photochromic dye spiropyran (SP) conjugated to the backbone of the targeting ligand hyaluronic acid (HA; HA-SP). Graphene oxide (GO) was reduced by prepared HA-SP accepting the advantages of catechol chemistry under mildly alkaline condition enabling to achieve functionalized graphene (rGO/HA-SP) as fluorescent nanoparticles. Due to containing HA, rGO/HA-SP can bind to the CD44 cell receptors. The prepared rGO/HA-SP is able to retain its photochromic features and can be converted to merocyanine (MC) form upon irradiation with UV light (wavelength: 365 nm) displaying purple color. Photochromic behavior of rGO/HA-SP was monitored by UV-vis and fluorescence spectroscopy. In vitro fluorescence behavior, examined by confocal laser scanning microscope (CLSM), of rGO/HA-SP in cancerous A549 cell lines assured that efficient delivery of rGO/HA-SP was gained due to HA as targeting ligand. In this work, we have shown that in vivo fluorescence image of spiropyran is possible by administrating MC form solution of rGO/HA-SP using Balb/C mice as in vivo modal. Accumulation of rGO/HA-SP in tumor tissue from biodistribution analysis strongly supports the specific delivery of prepared graphene to the target destination. The well tuned drug release manner from the surface of rGO/HA-SP strongly recommends the developed material not only as fluorescent probe for diagnosis but also as a drug carrier in drug delivery system. PMID:24106989

  1. Therapeutic Antibody-Induced Vascular Toxicity Due to Off-Target Activation of Nitric Oxide in Cynomolgus Monkeys.

    PubMed

    Pai, Rama; Ma, Ning; Connor, Anu V; Danilenko, Dimitry M; Tarrant, Jacqueline M; Salvail, Dany; Wong, Lisa; Hartley, Dylan P; Misner, Dinah; Stefanich, Eric; Wu, Yan; Chen, Yongmei; Wang, Hong; Dambach, Donna M

    2016-06-01

    PRO304186, a humanized monoclonal antibody targeting soluble interleukin-17 A and F, was developed for autoimmune and inflammatory disease indications. When administered to cynomolgus monkeys PRO304186 induced unexpected adverse effects characterized by clinical signs of hematemesis, hematochezia, and moribundity. Pathology findings included hemorrhage throughout the gastrointestinal tract without any evidence of vascular wall damage or inflammatory cellular infiltration. Mechanistic investigation of these effects revealed mild elevations of serum MCP-1 and IL-12/23 but without a classical proinflammatory profile in PRO304186-treated animals. In vitro studies demonstrated off-target effects on vascular endothelial cells including activation of nitric oxide synthase leading to production of nitric oxide (NO) accompanied by increased mitochondrial membrane depolarization, glutathione depletion, and increased paracellular permeability. Additionally, endothelial cell-PRO304186-conditioned medium reduced myosin light chain phosphorylation in vascular smooth muscle cells. Furthermore, an ex vivo study utilizing segments from cynomolgus aorta and femoral artery confirmed PRO304186-induced endothelium-dependent smooth muscle relaxation and vasodilation mediated via NO. Finally, a single dose of PRO304186 in cynomolgus monkeys induced a rapid and pronounced increase in NO in the portal circulation that preceded a milder elevation of NO in the systemic circulation and corresponded temporally with systemic hypotension; findings consistent with NO-mediated vasodilation leading to hypotension. These changes were associated with non-inflammatory, localized hemorrhage in the gastrointestinal tract consistent with hemodynamic vascular injury associated with intense local vasodilation. Together, these data demonstrate that PRO304186-associated toxicity in monkeys was due to an off-target effect on endothelium that involved regional NO release resulting in severe systemic

  2. Improved Yields of Iodine-124 from the Enriched Tellurium-124 Dioxide/Aluminum Oxide Target

    NASA Astrophysics Data System (ADS)

    Finn, R. D.; Qiao, J.; Nacca, A.; Sheh, Y.; Lom, C.; Balatoni, J.; Cai, S.; Bornmann, W.; Pentlow, K.

    2003-08-01

    The escalating clinical application of Positron Emission Tomography results from the novel radiotracers which are available to monitor specific biochemical or physiologic processes. Future developments of the technique will require an increasing availability of additional unique radioligands and radionuclides. Iodine-124, a radionuclide whose potential for both diagnostic and therapeutic applications is widely recognized, has been prepared at Memorial Sloan-Kettering Cancer Center on a weekly basis for several years (1). With its characteristic 4.18 day half life and complex decay scheme (2) which includes positron emission (22.0 ± 0.5%) and electron capture (78 ± 0.5%), this radionuclide has been shown to be appropriate for radiotracers describing slow physiologic processes with the clearance of non-specific radioactivity. The refinements and modifications being engineered into the cyclotron target system to increase the absolute yield of recoverable radioactivity from each irradiation and its chemical processing of the reusable solid target matrix are described..

  3. RGD-functionalized ultrasmall iron oxide nanoparticles for targeted T1-weighted MR imaging of gliomas

    NASA Astrophysics Data System (ADS)

    Luo, Yu; Yang, Jia; Yan, Yu; Li, Jingchao; Shen, Mingwu; Zhang, Guixiang; Mignani, Serge; Shi, Xiangyang

    2015-08-01

    We report a convenient approach to prepare ultrasmall Fe3O4 nanoparticles (NPs) functionalized with an arginylglycylaspartic acid (RGD) peptide for in vitro and in vivo magnetic resonance (MR) imaging of gliomas. In our work, stable sodium citrate-stabilized Fe3O4 NPs were prepared by a solvothermal route. Then, the carboxylated Fe3O4 NPs stabilized with sodium citrate were conjugated with polyethylene glycol (PEG)-linked RGD. The formed ultrasmall RGD-functionalized nanoprobe (Fe3O4-PEG-RGD) was fully characterized using different techniques. We show that these Fe3O4-PEG-RGD particles with a size of 2.7 nm are water-dispersible, stable, cytocompatible and hemocompatible in a given concentration range, and display targeting specificity to glioma cells overexpressing αvβ3 integrin in vitro. With the relatively high r1 relaxivity (r1 = 1.4 mM-1 s-1), the Fe3O4-PEG-RGD particles can be used as an efficient nanoprobe for targeted T1-weighted positive MR imaging of glioma cells in vitro and the xenografted tumor model in vivo via an active RGD-mediated targeting pathway. The developed RGD-functionalized Fe3O4 NPs may hold great promise to be used as a nanoprobe for targeted T1-weighted MR imaging of different αvβ3 integrin-overexpressing cancer cells or biological systems.We report a convenient approach to prepare ultrasmall Fe3O4 nanoparticles (NPs) functionalized with an arginylglycylaspartic acid (RGD) peptide for in vitro and in vivo magnetic resonance (MR) imaging of gliomas. In our work, stable sodium citrate-stabilized Fe3O4 NPs were prepared by a solvothermal route. Then, the carboxylated Fe3O4 NPs stabilized with sodium citrate were conjugated with polyethylene glycol (PEG)-linked RGD. The formed ultrasmall RGD-functionalized nanoprobe (Fe3O4-PEG-RGD) was fully characterized using different techniques. We show that these Fe3O4-PEG-RGD particles with a size of 2.7 nm are water-dispersible, stable, cytocompatible and hemocompatible in a given concentration

  4. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  5. High molecular weight chitosan derivative polymeric micelles encapsulating superparamagnetic iron oxide for tumor-targeted magnetic resonance imaging

    PubMed Central

    Xiao, Yunbin; Lin, Zuan Tao; Chen, Yanmei; Wang, He; Deng, Ya Li; Le, D Elizabeth; Bin, Jianguo; Li, Meiyu; Liao, Yulin; Liu, Yili; Jiang, Gangbiao; Bin, Jianping

    2015-01-01

    Magnetic resonance imaging (MRI) contrast agents based on chitosan derivatives have great potential for diagnosing diseases. However, stable tumor-targeted MRI contrast agents using micelles prepared from high molecular weight chitosan derivatives are seldom reported. In this study, we developed a novel tumor-targeted MRI vehicle via superparamagnetic iron oxide nanoparticles (SPIONs) encapsulated in self-aggregating polymeric folate-conjugated N-palmitoyl chitosan (FAPLCS) micelles. The tumor-targeting ability of FAPLCS/SPIONs was demonstrated in vitro and in vivo. The results of dynamic light scattering experiments showed that the micelles had a relatively narrow size distribution (136.60±3.90 nm) and excellent stability. FAPLCS/SPIONs showed low cytotoxicity and excellent biocompatibility in cellular toxicity tests. Both in vitro and in vivo studies demonstrated that FAPLCS/SPIONs bound specifically to folate receptor-positive HeLa cells, and that FAPLCS/SPIONs accumulated predominantly in established HeLa-derived tumors in mice. The signal intensities of T2-weighted images in established HeLa-derived tumors were reduced dramatically after intravenous micelle administration. Our study indicates that FAPLCS/SPION micelles can potentially serve as safe and effective MRI contrast agents for detecting tumors that overexpress folate receptors. PMID:25709439

  6. Highly conductive indium zinc oxide prepared by reactive magnetron cosputtering technique using indium and zinc metallic targets

    SciTech Connect

    Tsai, T. K.; Chen, H. C.; Lee, J. H.; Huang, Y. Y.; Fang, J. S.

    2010-05-15

    Zn-doped In{sub 2}O{sub 3} film is frequently deposited from an oxide target; but the use of metallic target is increasingly expected as preparing the film with comparable properties. This work aimed to prepare a highly conductive and transparent Zn-doped In{sub 2}O{sub 3} thin film on Corning Eagle{sup 2000} glass substrate by magnetron cosputtering method using indium and zinc targets. Structural characterization was performed using x-ray diffraction and x-ray photoelectron spectroscopy. The film had an amorphous structure when the film was prepared on an unheated substrate, but had an In{sub 2}O{sub 3} polycrystalline structure when the film was deposited on 150 and 300 deg. C substrates. The electrical properties of the film were greatly affected by annealing; the Zn-doped In{sub 2}O{sub 3} film had a low resistivity of 6.1x10{sup -4} {Omega} cm and an average transmittance of 81.7% when the film was deposited without substrate heating and followed a 600 deg. C annealing.

  7. Neurospora crassa transcriptomics reveals oxidative stress and plasma membrane homeostasis biology genes as key targets in response to chitosan

    PubMed Central

    Lopez-Moya, Federico; Kowbel, David; Nueda, Ma José; Palma-Guerrero, Javier; Glass, N. Louise; Lopez-Llorca, Luis Vicente

    2016-01-01

    Chitosan is a natural polymer with antimicrobial activity. Chitosan causes plasma membrane permeabilization and induction of intracellular reactive oxygen species (ROS) in Neurospora crassa. We have determined the transcriptional profile of N. crassa to chitosan and identified the main gene targets involved in the cellular response to this compound. Global network analyses showed membrane, transport and oxidoreductase activity as key nodes affected by chitosan. Activation of oxidative metabolism indicates the importance of ROS and cell energy together with plasma membrane homeostasis in N. crassa response to chitosan. Deletion strain analysis of chitosan susceptibility pointed, NCU03639 encoding a class 3 lipase, involved in plasma membrane repair by lipid replacement and NCU04537 a MFS monosaccharide transporter related with assimilation of simple sugars, as main gene targets of chitosan. NCU10521, a glutathione S-transferase-4 involved in the generation of reducing power for scavenging intracellular ROS is also a determinant chitosan gene target. Ca2+ increased tolerance to chitosan in N. crassa. Growth of NCU10610 (fig 1 domain) and SYT1 (a synaptotagmin) deletion strains was significantly increased by Ca2+ in presence of chitosan. Both genes play a determinant role in N. crassa membrane homeostasis. Our results are of paramount importance for developing chitosan as antifungal. PMID:26694141

  8. Integrin-targeting thermally cross-linked superparamagnetic iron oxide nanoparticles for combined cancer imaging and drug delivery

    NASA Astrophysics Data System (ADS)

    Yu, Mi Kyung; Park, Jinho; Jeong, Yong Yeon; Moon, Woo Kyung; Jon, Sangyong

    2010-10-01

    We report multifunctional nanoparticles that are capable of cancer targeting and simultaneous cancer imaging and therapy. The nanoparticles are composed of cyclic arginine-glycine-aspartic acid (cRGD) peptide ligand bioconjugated thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) that enable loading of the anticancer drug doxorubicin (Dox). The cyclic RGD-conjugated TCL-SPION (cRGD_TCL-SPION) had a mean hydrodynamic size of 34 ± 8 nm with approximately 0.39 wt% of cyclic RGD attached to the surface of the nanoparticles. The cRGD_TCL-SPION exhibited preferential binding towards target cancer cells (U87MG, integrin αvβ3 +) when analyzed by T2-weighted magnetic resonance (MR) imaging. When Dox was loaded onto the polymeric coating layers of cRGD_TCL-SPION via ionic interaction, the resulting Dox-loaded cRGD_TCL-SPION (Dox@cRGD_TCL-SPION) showed much higher cytotoxicity in U87MG cells than Dox@TCL-SPION lacking cRGD (IC50 value of 0.02 µM versus 0.12 µM). These results suggest that Dox@cRGD_TCL-SPION has potential for use as an integrin-targeted, combined imaging and therapeutic agent.

  9. Neurospora crassa transcriptomics reveals oxidative stress and plasma membrane homeostasis biology genes as key targets in response to chitosan.

    PubMed

    Lopez-Moya, Federico; Kowbel, David; Nueda, Maria José; Palma-Guerrero, Javier; Glass, N Louise; Lopez-Llorca, Luis Vicente

    2016-02-01

    Chitosan is a natural polymer with antimicrobial activity. Chitosan causes plasma membrane permeabilization and induction of intracellular reactive oxygen species (ROS) in Neurospora crassa. We have determined the transcriptional profile of N. crassa to chitosan and identified the main gene targets involved in the cellular response to this compound. Global network analyses showed membrane, transport and oxidoreductase activity as key nodes affected by chitosan. Activation of oxidative metabolism indicates the importance of ROS and cell energy together with plasma membrane homeostasis in N. crassa response to chitosan. Deletion strain analysis of chitosan susceptibility pointed NCU03639 encoding a class 3 lipase, involved in plasma membrane repair by lipid replacement, and NCU04537 a MFS monosaccharide transporter related to assimilation of simple sugars, as main gene targets of chitosan. NCU10521, a glutathione S-transferase-4 involved in the generation of reducing power for scavenging intracellular ROS is also a determinant chitosan gene target. Ca(2+) increased tolerance to chitosan in N. crassa. Growth of NCU10610 (fig 1 domain) and SYT1 (a synaptotagmin) deletion strains was significantly increased by Ca(2+) in the presence of chitosan. Both genes play a determinant role in N. crassa membrane homeostasis. Our results are of paramount importance for developing chitosan as an antifungal. PMID:26694141

  10. Deposition and characterization of titania-silica optical multilayers by asymmetric bipolar pulsed dc sputtering of oxide targets

    NASA Astrophysics Data System (ADS)

    Sagdeo, P. R.; Shinde, D. D.; Misal, J. S.; Kamble, N. M.; Tokas, R. B.; Biswas, A.; Poswal, A. K.; Thakur, S.; Bhattacharyya, D.; Sahoo, N. K.; Sabharwal, S. C.

    2010-02-01

    Titania-silica (TiO2/SiO2) optical multilayer structures have been conventionally deposited by reactive sputtering of metallic targets. In order to overcome the problems of arcing, target poisoning and low deposition rates encountered there, the application of oxide targets was investigated in this work with asymmetric bipolar pulsed dc magnetron sputtering. In order to evaluate the usefulness of this deposition methodology, an electric field optimized Fabry Perot mirror for He-Cd laser (λ = 441.6 nm) spectroscopy was deposited and characterized. For comparison, this mirror was also deposited by the reactive electron beam (EB) evaporation technique. The mirrors developed by the two complementary techniques were investigated for their microstructural and optical reflection properties invoking atomic force microscopy, ellipsometry, grazing incidence reflectometry and spectrophotometry. From these measurements the layer geometry, optical constants, mass density, topography, surface and interface roughness and disorder parameters were evaluated. The microstructural properties and spectral functional characteristics of the pulsed dc sputtered multilayer mirror were found to be distinctively superior to the EB deposited mirror. The knowledge gathered during this study has been utilized to develop a 21-layer high-pass edge filter for radio photoluminescence dosimetry.

  11. Design of multifunctional magnetic iron oxide nanoparticles/mitoxantrone-loaded liposomes for both magnetic resonance imaging and targeted cancer therapy

    PubMed Central

    He, Yingna; Zhang, Linhua; Zhu, Dunwan; Song, Cunxian

    2014-01-01

    Tumor-targeting multifunctional liposomes simultaneously loaded with magnetic iron oxide nanoparticles (MIONs) as a magnetic resonance imaging (MRI) contrast agent and anticancer drug, mitoxantrone (Mit), were developed for targeted cancer therapy and ultrasensitive MRI. The gonadorelin-functionalized MION/Mit-loaded liposome (Mit-GML) showed significantly increased uptake in luteinizing hormone–releasing hormone (LHRH) receptor overexpressing MCF-7 (Michigan Cancer Foundation-7) breast cancer cells over a gonadorelin-free MION/Mit-loaded liposome (Mit-ML) control, as well as in an LHRH receptor low-expressing Sloan-Kettering HER2 3+ Ovarian Cancer (SK-OV-3) cell control, thereby leading to high cytotoxicity against the MCF-7 human breast tumor cell line. The Mit-GML formulation was more effective and less toxic than equimolar doses of free Mit or Mit-ML in the treatment of LHRH receptors overexpressing MCF-7 breast cancer xenografts in mice. Furthermore, the Mit-GML demonstrated much higher T2 enhancement than did Mit-ML controls in vivo. Collectively, the study indicates that the integrated diagnostic and therapeutic design of Mit-GML nanomedicine potentially allows for the image-guided, target-specific treatment of cancer. PMID:25187709

  12. Nanoimmunoliposome Delivery of Superparamagnetic Iron Oxide Markedly Enhances Targeting and Uptake in Human Cancer Cells In Vitro and In Vivo

    PubMed Central

    Yang, Chengli; Rait, Antonina; Pirollo, Kathleen F.; Dagata, John A.; Farkas, Natalia; Chang, Esther H.

    2008-01-01

    To circumvent the problem of reduction of the supermagnetic properties of superparamagnetic iron oxide (SPIO) nanoparticles after chemical modification to conjugate targeting molecules, we have adapted a tumor-targeting nanoimmunoliposome platform technology (scL) to encapsulate and deliver SPIO (scL-SPIO) in vitro and in vivo without chemical modification. Scanning probe microscopy, confocal microscopy, and Prussian blue staining were employed to analyze the scL-SPIO nanoparticles and assess intracellular uptake and distribution of SPIO in vitro. In vivo targeting and tumor-specific uptake of scL-SPIO was examined using fluorescent-labeled SPIO. We demonstrated that SPIO encapsulation in the scL complex results in approximately an 11 fold increase in SPIO uptake in human cancer cells in vitro, with distribution to cytoplasm and nucleus. Moreover, the scL nanocomplex specifically and efficiently delivered SPIO into tumor cells after systemic administration, demonstrating the potential of this approach to enhance local tumor concentration and the utility of SPIO for clinical applications. PMID:18676207

  13. Remote magnetic targeting of iron oxide nanoparticles for cardiovascular diagnosis and therapeutic drug delivery: where are we now?

    PubMed Central

    Bietenbeck, Michael; Florian, Anca; Faber, Cornelius; Sechtem, Udo; Yilmaz, Ali

    2016-01-01

    Magnetic resonance imaging (MRI) allows for an accurate assessment of both functional and structural cardiac parameters, and thereby appropriate diagnosis and validation of cardiovascular diseases. The diagnostic yield of cardiovascular MRI examinations is often increased by the use of contrast agents that are almost exclusively based on gadolinium compounds. Another clinically approved contrast medium is composed of superparamagnetic iron oxide nanoparticles (IONs). These particles may expand the field of contrast-enhanced cardiovascular MRI as recently shown in clinical studies focusing on acute myocardial infarction (AMI) and atherosclerosis. Furthermore, IONs open up new research opportunities such as remote magnetic drug targeting (MDT). The approach of MDT relies on the coupling of bioactive molecules and magnetic nanoparticles to form an injectable complex. This complex, in turn, can be attracted to and retained at a desired target inside the body with the help of applied magnetic fields. In comparison to common systemic drug applications, MDT techniques promise both higher concentrations at the target site and lower concentrations elsewhere in the body. Moreover, concurrent or subsequent MRI can be used for noninvasive monitoring of drug distribution and successful delivery to the desired organ in vivo. This review does not only illustrate the basic conceptual and biophysical principles of IONs, but also focuses on new research activities and achievements in the cardiovascular field, mainly in the management of AMI. Based on the presentation of successful MDT applications in preclinical models of AMI, novel approaches and the translational potential of MDT are discussed. PMID:27486321

  14. Pyruvate dehydrogenase complex: metabolic link to ischemic brain injury and target of oxidative stress.

    PubMed

    Martin, Erica; Rosenthal, Robert E; Fiskum, Gary

    The mammalian pyruvate dehydrogenase complex (PDHC) is a mitochondrial matrix enzyme complex (greater than 7 million Daltons) that catalyzes the oxidative decarboxylation of pyruvate to form acetyl CoA, nicotinamide adenine dinucleotide (the reduced form, NADH), and CO(2). This reaction constitutes the bridge between anaerobic and aerobic cerebral energy metabolism. PDHC enzyme activity and immunoreactivity are lost in selectively vulnerable neurons after cerebral ischemia and reperfusion. Evidence from experiments carried out in vitro suggests that reperfusion-dependent loss of activity is caused by oxidative protein modifications. Impaired enzyme activity may explain the reduced cerebral glucose and oxygen consumption that occurs after cerebral ischemia. This hypothesis is supported by the hyperoxidation of mitochondrial electron transport chain components and NAD(H) that occurs during reperfusion, indicating that NADH production, rather than utilization, is rate limiting. Additional support comes from the findings that immediate postischemic administration of acetyl-L-carnitine both reduces brain lactate/pyruvate ratios and improves neurologic outcome after cardiac arrest in animals. As acetyl-L-carnitine is converted to acetyl CoA, the product of the PDHC reaction, it follows that impaired production of NADH is due to reduced activity of either PDHC or one or more steps in glycolysis. Impaired cerebral energy metabolism and PDHC activity are associated also with neurodegenerative disorders including Alzheimer's disease and Wernicke-Korsakoff syndrome, suggesting that this enzyme is an important link in the pathophysiology of both acute brain injury and chronic neurodegeneration. PMID:15562436

  15. Magnetic tumor targeting of β-glucosidase immobilized iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Zhang, Jian; David, Allan E.; Yang, Victor C.

    2013-09-01

    Directed enzyme/prodrug therapy (DEPT) has promising application for cancer therapy. However, most current DEPT strategies face shortcomings such as the loss of enzyme activity during preparation, low delivery and transduction efficiency in vivo and difficultly of monitoring. In this study, a novel magnetic directed enzyme/prodrug therapy (MDEPT) was set up by conjugating β-glucosidase (β-Glu) to aminated, starch-coated, iron oxide magnetic iron oxide nanoparticles (MNPs), abbreviated as β-Glu-MNP, using glutaraldehyde as the crosslinker. This β-Glu-MNP was then characterized in detail by size distribution, zeta potential, FTIR spectra, TEM, SQUID and magnetophoretic mobility analysis. Compared to free enzyme, the conjugated β-Glu on MNPs retained 85.54% ± 6.9% relative activity and showed much better temperature stability. The animal study results showed that β-Glu-MNP displays preferable pharmacokinetics characteristics in relation to MNPs. With an adscititious magnetic field on the surface of a tumor, a significant quantity of β-Glu-MNP was selectively delivered into a subcutaneous tumor of a glioma-bearing mouse. Remarkably, the enzyme activity of the delivered β-Glu in tumor lesions showed as high as 20.123±5.022 mU g-1 tissue with 2.14 of tumor/non-tumor β-Glu activity.

  16. Magnetic tumor targeting of β-Glucosidase immobilized iron oxide nanoparticles

    PubMed Central

    Zhou, Jie; Zhang, Jian; David, Allan E.; Yang, Victor C.

    2014-01-01

    Directed enzyme/prodrug therapy (DEPT) has promising application for cancer therapy. However, most current DEPT strategies face shortcomings such as the loss of enzyme activity during preparation, low delivery and transduction efficiency in vivo, difficult to be monitored. In current study, a novel magnetic directed enzyme/prodrug therapy (MDEPT) was set up by conjugating β-Glucosidase (β-Glu) to aminated, starch-coated, iron oxide magnetic iron oxide nanoparticles (MNP), abbreviated as β-Glu-MNP, using glutaraldehyde as the crosslinker. This β-Glu-MNP was then characterized in detail by size distribution, zeta potential, FTIR spectra, TEM, SQUID and magnetophoretic mobility analysis. Compared to free enzyme, the conjugated β-Glu on MNP remained 85.54%±6.9% relative activity and showed much better temperature stability. relative activity and showed much better temperature stability. The animal study results showed that β-Glu-MNP display preferable pharmacokinetics characteristic in relation to MNP. With adscititious magnetic field on the surface of tumor, a significant quantity of β-Glu-MNP was selectively delivered into a subcutaneous tumor of glioma-bearing mice. Remarkably, the enzyme activity of the delivered β-Glu in tumor lesions showed as high as 20.123 ± 5.022 mU/g tissue with 2.14 of tumor/non-turmor of β-Glu activity. PMID:23974977

  17. Pyruvate Dehydrogenase Complex: Metabolic Link to Ischemic Brain Injury and Target of Oxidative Stress

    PubMed Central

    Martin, Erica; Rosenthal, Robert E.; Fiskum, Gary

    2008-01-01

    The mammalian pyruvate dehydrogenase complex (PDHC) is a mitochondrial matrix enzyme complex (greater than 7 million Daltons) that catalyzes the oxidative decarboxylation of pyruvate to form acetyl CoA, nicotinamide adenine dinucleotide (the reduced form, NADH), and CO2. This reaction constitutes the bridge between anaerobic and aerobic cerebral energy metabolism. PDHC enzyme activity and immunoreactivity are lost in selectively vulnerable neurons after cerebral ischemia and reperfusion. Evidence from experiments carried out in vitro suggests that reperfusion-dependent loss of activity is caused by oxidative protein modifications. Impaired enzyme activity may explain the reduced cerebral glucose and oxygen consumption that occurs after cerebral ischemia. This hypothesis is supported by the hyperoxidation of mitochondrial electron transport chain components and NAD(H) that occurs during reperfusion, indicating that NADH production, rather than utilization, is rate limiting. Additional support comes from the findings that immediate postischemic administration of acetyl-l-carnitine both reduces brain lactate/pyruvate ratios and improves neurologic outcome after cardiac arrest in animals. As acetyl-l-carnitine is converted to acetyl CoA, the product of the PDHC reaction, it follows that impaired production of NADH is due to reduced activity of either PDHC or one or more steps in glycolysis. Impaired cerebral energy metabolism and PDHC activity are associated also with neurodegenerative disorders including Alzheimer's disease and Wernicke-Korsakoff syndrome, suggesting that this enzyme is an important link in the pathophysiology of both acute brain injury and chronic neurodegeneration. PMID:15562436

  18. Mitochondrial Dysfunction and Oxidative Stress in Asthma: Implications for Mitochondria-Targeted Antioxidant Therapeutics

    PubMed Central

    Reddy, P. Hemachandra

    2011-01-01

    Asthma is a complex, inflammatory disorder characterized by airflow obstruction of variable degrees, bronchial hyper-responsiveness, and airway inflammation. Asthma is caused by environmental factors and a combination of genetic and environmental stimuli. Genetic studies have revealed that multiple loci are involved in the etiology of asthma. Recent cellular, molecular, and animal-model studies have revealed several cellular events that are involved in the progression of asthma, including: increased Th2 cytokines leading to the recruitment of inflammatory cells to the airway, and an increase in the production of reactive oxygen species and mitochondrial dysfunction in the activated inflammatory cells, leading to tissue injury in the bronchial epithelium. Further, aging and animal model studies have revealed that mitochondrial dysfunction and oxidative stress are involved and play a large role in asthma. Recent studies using experimental allergic asthmatic mouse models and peripheral cells and tissues from asthmatic humans have revealed antioxidants as promising treatments for people with asthma. This article summarizes the latest research findings on the involvement of inflammatory changes, and mitochondrial dysfunction/oxidative stress in the development and progression of asthma. This article also addresses the relationship between aging and age-related immunity in triggering asthma, the antioxidant therapeutic strategies in treating people with asthma. PMID:21461182

  19. Nitric oxide homeostasis as a target for drug additives to cardioplegia

    PubMed Central

    Podesser, B K; Hallström, S

    2007-01-01

    The vascular endothelium of the coronary arteries has been identified as the important organ that locally regulates coronary perfusion and cardiac function by paracrine secretion of nitric oxide (NO) and vasoactive peptides. NO is constitutively produced in endothelial cells by endothelial nitric oxide synthase (eNOS). NO derived from this enzyme exerts important biological functions including vasodilatation, scavenging of superoxide and inhibition of platelet aggregation. Routine cardiac surgery or cardiologic interventions lead to a serious temporary or persistent disturbance in NO homeostasis. The clinical consequences are “endothelial dysfunction”, leading to “myocardial dysfunction”: no- or low-reflow phenomenon and temporary reduction of myocardial pump function. Uncoupling of eNOS (one electron transfer to molecular oxygen, the second substrate of eNOS) during ischemia-reperfusion due to diminished availability of L-arginine and/or tetrahydrobiopterin is even discussed as one major source of superoxide formation. Therefore maintenance of normal NO homeostasis seems to be an important factor protecting from ischemia/reperfusion (I/R) injury. Both, the clinical situations of cardioplegic arrest as well as hypothermic cardioplegic storage are followed by reperfusion. However, the presently used cardioplegic solutions to arrest and/or store the heart, thereby reducing myocardial oxygen consumption and metabolism, are designed to preserve myocytes mainly and not endothelial cells. This review will focus on possible drug additives to cardioplegia, which may help to maintain normal NO homeostasis after I/R. PMID:17486142

  20. In vivo targeting of metastatic breast cancer via tumor vasculature-specific nano-graphene oxide.

    PubMed

    Yang, Dongzhi; Feng, Liangzhu; Dougherty, Casey A; Luker, Kathryn E; Chen, Daiqin; Cauble, Meagan A; Banaszak Holl, Mark M; Luker, Gary D; Ross, Brian D; Liu, Zhuang; Hong, Hao

    2016-10-01

    Angiogenesis, i.e. the formation of neovasculatures, is a critical process during cancer initiation, progression, and metastasis. Targeting of angiogenic markers on the tumor vasculature can result in more efficient delivery of nanomaterials into tumor since no extravasation is required. Herein we demonstrated efficient targeting of breast cancer metastasis in an experimental murine model with nano-graphene oxide (GO), which was conjugated to a monoclonal antibody (mAb) against follicle-stimulating hormone receptor (FSHR). FSHR has been confirmed to be a highly selective tumor vasculature marker, which is abundant in both primary and metastatic tumors. These functionalized GO nano-conjugates had diameters of ∼120 nm based on atomic force microscopy (AFM), TEM, and dynamic laser scattering (DLS) measurement. (64)Cu was incorporated as a radiolabel which enabled the visualization of these GO conjugates by positron emission tomography (PET) imaging. Breast cancer lung metastasis model was established by intravenous injection of click beetle green luciferase-transfected MDA-MB-231 (denoted as cbgLuc-MDA-MB-231) breast cancer cells into female nude mice and the tumor growth was monitored by bioluminescence imaging (BLI). Systematic in vitro and in vivo studies have been performed to investigate the stability, targeting efficacy and specificity, and tissue distribution of GO conjugates. Flow cytometry and fluorescence microscopy examination confirmed the targeting specificity of FSHR-mAb attached GO conjugates against cellular FSHR. More potent and persistent uptake of (64)Cu-NOTA-GO-FSHR-mAb in cbgLuc-MDA-MB-231 nodules inside the lung was witnessed when compared with that of non-targeted GO conjugates ((64)Cu-NOTA-GO). Histology evaluation also confirmed the vasculature accumulation of GO-FSHR-mAb conjugates in tumor at early time points while they were non-specifically captured in liver and spleen. In addition, these GO conjugates can serve as good drug carriers

  1. Isorhamnetin protects against oxidative stress by activating Nrf2 and inducing the expression of its target genes

    SciTech Connect

    Yang, Ji Hye; Shin, Bo Yeon; Han, Jae Yun; Kim, Mi Gwang; Wi, Ji Eun; Kim, Young Woo; Cho, Il Je; Kim, Sang Chan; Shin, Sang Mi; Ki, Sung Hwan

    2014-01-15

    Isorhamentin is a 3′-O-methylated metabolite of quercetin, and has been reported to have anti-inflammatory and anti-proliferative effects. However, the effects of isorhamnetin on Nrf2 activation and on the expressions of its downstream genes in hepatocytes have not been elucidated. Here, we investigated whether isorhamnetin has the ability to activate Nrf2 and induce phase II antioxidant enzyme expression, and to determine the protective role of isorhamnetin on oxidative injury in hepatocytes. In HepG2 cells, isorhamnetin increased the nuclear translocation of Nrf2 in a dose- and time-dependent manner, and consistently, increased antioxidant response element (ARE) reporter gene activity and the protein levels of hemeoxygenase (HO-1) and of glutamate cysteine ligase (GCL), which resulted in intracellular GSH level increases. The specific role of Nrf2 in isorhamnetin-induced Nrf2 target gene expression was verified using an ARE-deletion mutant plasmid and Nrf2-knockout MEF cells. Deletion of the ARE in the promoter region of the sestrin2 gene, which is recently identified as the Nrf2 target gene by us, abolished the ability of isorhamnetin to increase luciferase activity. In addition, Nrf2 deficiency completely blocked the ability of isorhamnetin to induce HO-1 and GCL. Furthermore, isorhamnetin pretreatment blocked t-BHP-induced ROS production and reversed GSH depletion by t-BHP and consequently, due to reduced ROS levels, decreased t-BHP-induced cell death. In addition isorhamnetin increased ERK1/2, PKCδ and AMPK phosphorylation. Finally, we showed that Nrf2 deficiency blocked the ability of isorhamnetin to protect cells from injury induced by t-BHP. Taken together, our results demonstrate that isorhamnetin is efficacious in protecting hepatocytes against oxidative stress by Nrf2 activation and in inducing the expressions of its downstream genes. - Highlights: • We investigated the effect of isorhamnetin on Nrf2 activation. • Isorhamnetin increased Nrf2

  2. Features of the synthesis of nanocolloid oxides by laser ablation of bulk metal targets in solutions

    NASA Astrophysics Data System (ADS)

    Lapin, Ivan N.; Svetlichnyi, Valery A.

    2015-12-01

    Laser ablation of bulk targets in a fluid -- a promising new method for the synthesis of "pure" nanocolloids. Nanocrystalline materials produced by laser ablation are widely used in biology, medicine, and catalysis. High local temperature during ablation and large surface area of the particles promote chemical reactions and the formation of a complex composition of nanoparticles. In this paper the characteristics of the process of ablation and the obtaining of nanoparticles in a liquid by laser ablation of active materials (Zn, Ce, Ti, Si) were studied. Ways of increasing the productivity of laser ablation were discussed. Characterization of nanocolloids and nanocrystalline powders were performed.

  3. Ag-SHEATHED Bi2Sr2CaCu2O8 Square Wire Insulated with Oxidized Hastelloy Fiber Braid

    NASA Astrophysics Data System (ADS)

    Watanabe, K.; Nishijima, G.; Awaji, S.; Hikichi, Y.; Hasegawa, T.

    2008-03-01

    Oxidized Hastelloy X (Hx) fiber braid has been demonstrated to work well as a good electric insulation of Ag-sheathed Bi2Sr2CaCu2O8 (Ag/Bi2212) wires. In order to develop a wind-and-react processed Ag/Bi2212 superconducting magnet with a high coil current density, we fabricated a test coil employing 45 m long Ag/Bi2212 square shape wire with 50 μm Hx fiber braid. A test coil, whose size is 73 mm outer diameter, 64.5 mm inner diameter, and 74 mm coil winding height, consisted of 4 layers and 210 turns, and was heat-treated at around 890 °C in oxygen gas. The critical current Ic of the test coil was 245 A at 4.2 K in a self-field, corresponding to a 67% value of the short sample Ic heat-treated at the same time for comparison. Coil inductance was calculated to be 1.9 mH, and as a result, the same inductance value was obtained in the test coil. It was found that a Hx cloth knitting method enables us to insulate sufficiently between wires in Ag/Bi2212 square shape wire.

  4. A Mode-Locked Soliton Erbium-Doped Fiber Laser with a Single-Walled Carbon Nanotube Poly-Ethylene Oxide Film Saturable Absorber

    NASA Astrophysics Data System (ADS)

    Z. R. R. Rosdin, R.; F., Ahmad; M. Ali, N.; M. Nor, R.; R. Zulkepely, N.; W. Harun, S.; Arof, H.

    2014-09-01

    We present a simple, compact and low-cost mode-locked erbium-doped fiber laser (EDFL) using single-walled carbon nanotubes (SWCNTs) embedded in a poly-ethylene oxide (PEO) thin film as a passive saturable absorber. The film is fabricated by using a prepared homogeneous SWCNT solution, which is mixed with a diluted PEO solution and cast onto a glass Petri dish to form, by evaporation, a thin film. The 50 μm-thick film is sandwiched between two fiber connectors to construct a saturable absorber, which is then integrated in an EDFL cavity to generate self-started stable soliton pulses operating at 1560.8 nm. The soliton pulse starts to lase at a pump power threshold of 12.3 mW with a repetition rate of 11.21 MHz, a pulse width of 1.02 ps, an average output power of 0.65 mW and a pulse energy of 57.98 pJ.

  5. Mode-locked soliton erbium-doped fiber laser using a single-walled carbon nanotubes embedded in polyethylene oxide thin film saturable absorber

    NASA Astrophysics Data System (ADS)

    Ahmad, F.; Harun, S. W.; Nor, R. M.; Zulkepely, N. R.; Muhammad, F. D.; Arof, H.; Ahmad, H.

    2014-03-01

    We demonstrate a simple, compact, and low cost mode-locked erbium-doped fiber laser (EDFL) using a single-walled carbon nanotubes (SWCNTs) embedded in polyethylene oxide (PEO) thin film as a passive saturable absorber (SA). The film with a thickness of 50 μm was fabricated using a prepared homogeneous SWCNT solution with 0.1% loading percentage, which was mixed with a diluted PEO solution and casted onto a glass Petri dish to form a thin film by evaporation technique. The film is sandwiched between two fiber connectors to construct a SA, which is then integrated in an EDFL cavity to generate a self-started stable soliton pulses operating at 1558 nm. The soliton pulse starts to lase at pump power threshold of 17.6 mW with a repetition rate of 50 MHz, pulse width of 0.67 ps, average output power of 0.158 mW, pulse energy of 3.16 pJ, and peak power of 4.43 W.

  6. Covalent Bonding of Metal-Organic Framework-5/Graphene Oxide Hybrid Composite to Stainless Steel Fiber for Solid-Phase Microextraction of Triazole Fungicides from Fruit and Vegetable Samples.

    PubMed

    Zhang, Shuaihua; Yang, Qian; Wang, Wenchang; Wang, Chun; Wang, Zhi

    2016-04-01

    A hybrid material of the zinc-based metal-organic framework-5 and graphene oxide (metal-organic framework-5/graphene oxide) was prepared as a novel fiber coating material for solid-phase microextraction (SPME). The SPME fibers were fabricated by covalent bonding via chemical cross-linking between the coating material metal-organic framework-5/graphene oxide and stainless steel wire. The prepared fiber was used for the extraction of five triazole fungicides from fruit and vegetable samples. Gas chromatography coupled with microelectron capture detector (GC-μECD) was used for quantification. The developed method gave a low limit of detection (0.05-1.58 ng g(-1)) and good linearity (0.17-100 ng g(-1)) for the determination of the triazole fungicides in fruit and vegetable samples. The relative standard deviations (RSDs) for five replicate extractions of the triazole fungicides ranged from 3.7 to 8.9%. The method recoveries for spiked fungicides (5, 20, and 50 ng g(-1)) in grape, apple, cucumber, celery cabbage, pear, cabbage, and tomato samples were in the range of 85.6-105.8% with the RSDs ranging from 3.6 to 11.4%, respectively, depending on both the analytes and samples. The metal-organic framework-5/graphene oxide coated fiber was stable enough for 120 extraction cycles without a significant loss of extraction efficiency. The method was suitable for the determination of triazole fungicides in fruit and vegetable samples. PMID:26998567

  7. Ultra-long Pt nanolawns supported on TiO2-coated carbon fibers as 3D hybrid catalyst for methanol oxidation

    PubMed Central

    2012-01-01

    In this study, TiO2 thin film photocatalyst on carbon fibers was used to synthesize ultra-long single crystalline Pt nanowires via a simple photoreduction route (thermally activated photoreduction). It also acted as a co-catalytic material with Pt. Taking advantage of the high-aspect ratio of the Pt nanostructure as well as the excellent catalytic activity of TiO2, this hybrid structure has the great potential as the active anode in direct methanol fuel cells. The electrochemical results indicate that TiO2 is capable of transforming CO-like poisoning species on the Pt surface during methanol oxidation and contributes to a high CO tolerance of this Pt nanowire/TiO2 hybrid structure. PMID:22546416

  8. Thymosin Beta 4 Prevents Oxidative Stress by Targeting Antioxidant and Anti-Apoptotic Genes in Cardiac Fibroblasts

    PubMed Central

    Kumar, Sandeep; Gupta, Sudhiranjan

    2011-01-01

    Rationale Thymosin beta-4 (Tβ4) is a ubiquitous protein with diverse functions relating to cell proliferation and differentiation that promotes wound healing and modulates inflammatory responses. The effecter molecules targeted by Tβ4 for cardiac protection remains unknown. The purpose of this study is to determine the molecules targeted by Tβ4 that mediate cardio-protection under oxidative stress. Methods Rat neonatal fibroblasts cells were exposed to hydrogen peroxide (H2O2) in presence and absence of Tβ4 and expression of antioxidant, apoptotic and pro-fibrotic genes was evaluated by quantitative real-time PCR and western blotting. Reactive oxygen species (ROS) levels were estimated by DCF-DA using fluorescent microscopy and fluorimetry. Selected antioxidant and antiapoptotic genes were silenced by siRNA transfections in cardiac fibroblasts and the effect of Tβ4 on H2O2-induced profibrotic events was evaluated. Results Pre-treatment with Tβ4 resulted in reduction of the intracellular ROS levels induced by H2O2 in the cardiac fibroblasts. This was associated with an increased expression of antioxidant enzymes Cu/Zn superoxide dismutase (SOD) and catalase and reduction of Bax/Bcl2 ratio. Tβ4 treatment reduced the expression of pro-fibrotic genes [connective tissue growth factor (CTGF), collagen type-1 (Col-I) and collagen type-3 (Col-III)] in the cardiac fibroblasts. Silencing of Cu/Zn-SOD and catalase gene triggered apoptotic cell death in the cardiac fibroblasts, which was prevented by treatment with Tβ4. Conclusion This is the first report that exhibits the targeted molecules modulated by Tβ4 under oxidative stress utilizing the cardiac fibroblasts. Tβ4 treatment prevented the profibrotic gene expression in the in vitro settings. Our findings indicate that Tβ4 selectively targets and upregulates catalase, Cu/Zn-SOD and Bcl2, thereby, preventing H2O2-induced profibrotic changes in the myocardium. Further studies are warranted to elucidate the

  9. Autotract: Automatic cleaning and tracking of fibers

    PubMed Central

    Prieto, Juan C.; Yang, Jean Y.; Budin, François; Styner, Martin

    2016-01-01

    We propose a new tool named Autotract to automate fiber tracking in diffusion tensor imaging (DTI). Autotract uses prior knowledge from a source DTI and a set of corresponding fiber bundles to extract new fibers for a target DTI. Autotract starts by aligning both DTIs and uses the source fibers as seed points to initialize a tractography algorithm. We enforce similarity between the propagated source fibers and automatically traced fibers by computing metrics such as fiber length and fiber distance between the bundles. By analyzing these metrics, individual fiber tracts can be pruned. As a result, we show that both bundles have similar characteristics. Additionally, we compare the automatically traced fibers against bundles previously generated and validated in the target DTI by an expert. This work is motivated by medical applications in which known bundles of fiber tracts in the human brain need to be analyzed for multiple datasets. PMID:27065227

  10. Autotract: automatic cleaning and tracking of fibers

    NASA Astrophysics Data System (ADS)

    Prieto, Juan C.; Yang, Jean Y.; Budin, François; Styner, Martin

    2016-03-01

    We propose a new tool named Autotract to automate fiber tracking in diffusion tensor imaging (DTI). Autotract uses prior knowledge from a source DTI and a set of corresponding fiber bundles to extract new fibers for a target DTI. Autotract starts by aligning both DTIs and uses the source fibers as seed points to initialize a tractography algorithm. We enforce similarity between the propagated source fibers and automatically traced fibers by computing metrics such as fiber length and fiber distance between the bundles. By analyzing these metrics, individual fiber tracts can be pruned. As a result, we show that both bundles have similar characteristics. Additionally, we compare the automatically traced fibers against bundles previously generated and validated in the target DTI by an expert. This work is motivated by medical applications in which known bundles of fiber tracts in the human brain need to be analyzed for multiple datasets.

  11. Photocatalytic oxidation of low concentration 2,4-D solution with new TiO2 fiber catalyst in a continuous flow reactor.

    PubMed

    Terashima, Y; Ozaki, H; Giri, R R; Tano, T; Nakatsuji, S; Takanami, R; Taniguchi, S

    2006-01-01

    Environmental pollution by low concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) is a concern these days due to ever increasingly stringent regulations. Photocatalysis with immobilized TiO2 fiber is a promising oxidation method. Laboratory experiments on photocatalytic degradation of 0.045 mmol l(-1) 2,4-D with the world's first high-strength TiO2 fiber catalyst were carried out in a continuous flow reactor in which the degradations were, in general, similar to those with high 2,4-D concentrations investigated elsewhere. Degradation and mineralization of 2,4-D were significantly enhanced with no initial pH adjustments. The rate constants for total organic carbon (TOC) without pH adjustment were about two-fold bigger than the pH adjustment cases. CO2 gas measurement and carbon mass-balance were carried out for the first time, where about 34% organic carbon converted into CO2 gas during four-hour oxidation. 2,4-Dichlorophenol (2,4-DCP), phenol, benzyl alcohol and two unknowns (RT = 2.65 and 3.78 min.) were detected as aromatic intermediates while Phenol was the new aromatic in HPLC analysis. Dechlorination efficiencies were high (> 70%) in all the cases, and more than 90% efficiencies were observed in chloride mass balance. Bigger flow rates and solution temperature fixed at 20 degrees C without pH adjustment greatly enhanced 2,4-D mineralization. These results can be an important basis in applying the treatment method for dioxin-contaminated water and wastewater. PMID:17163013

  12. Iron oxide core oil-in-water emulsions as a multifunctional nanoparticle platform for tumor targeting and imaging

    PubMed Central

    Jarzyna, Peter A.; Skajaa, Torjus; Gianella, Anita; Cormode, David P.; Samber, Dan D.; Dickson, Stephen D.; Chen, Wei; Griffioen, Arjan W.; Fayad, Zahi A.; Mulder, Willem J. M.

    2009-01-01

    Nanoemulsions are increasingly investigated for the delivery of hydrophobic drugs to improve their bioavailability or make their administration possible. In the current study, oil-in-water emulsions with three different mean diameters (30, 60, and 95 nm) were developed as a new multimodality nanoparticle platform for tumor targeting and imaging. To that aim, hydrophobically coated iron oxide particles were included in the soybean oil core of the nanoemulsions to enable their detection with magnetic resonance imaging (MRI), while the conjugation of a near infrared fluorophore allowed optical imaging. The accumulation of this novel nanocomposite in subcutaneous human tumors in nude mice was demonstrated with MRI and fluorescence imaging in vivo, and with Perl’s staining of histological tumor sections ex vivo. PMID:19783295

  13. Core-shell composite particles composed of biodegradable polymer particles and magnetic iron oxide nanoparticles for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Oka, Chiemi; Ushimaru, Kazunori; Horiishi, Nanao; Tsuge, Takeharu; Kitamoto, Yoshitaka

    2015-05-01

    Core-shell composite particles with biodegradability and superparamagnetic behavior were prepared using a Pickering emulsion for targeted drug delivery based on magnetic guidance. The composite particles were composed of a core of biodegradable polymer and a shell of assembled magnetic iron oxide nanoparticles. It was found that the dispersibility of the nanoparticles is crucial for controlling the core-shell structure. The addition of a small amount of dispersant into the nanoparticle's suspension could improve the dispersibility