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Sample records for boron 8 target

  1. Laser-time resolved fluorimetric determination of trace of boron in U3O8

    International Nuclear Information System (INIS)

    In this work, a laser-time resolved fluorimetric determinatin of trace of boron in U3O8 had been developed. The boron complex with dibenzoyl methane (DBM) in a suitable medium is excited by a small nitrogen laser and emits the delay fluorescence with lifetime of 2 ms which is much longer than that of the fluorescence of uranium. Since the fluorescence of uranium doesn't interfere with determination of boron in the time resolved fluorimetric method boron need not be separated from uranium in advance. Thus the determination is very rapid and simple. The limit of determination is 0.02 ngB/ml. When 10 mgU is taken, 0.01 ppm of boron in uranium can be determined. Several samples of U3O8 with boron content from 0.04 to 0.5 ppm have been determined by using this method. The results of determination have been accordant with other methods

  2. Beryllium Target for Accelerator - Based Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    This work is part of a project for developing Accelerator Based Boron Neutron Capture Therapy (AB- BNCT) for which the generation of neutrons through nuclear reactions like 9Be(d,n) is necessary. In this paper first results of the design and development of such neutron production targets are presented. For this purpose, the neutron production target has to be able to withstand the mechanical and thermal stresses produced by intense beams of deuterons (of 1.4 MeV with a total current of about 30mA). In particular, the target should be able to dissipate an energy density of up to 1 kW/cm2 and preserve its physical and mechanical properties for a sufficient length of time under irradiation conditions and hydrogen damage. The target is proposed to consist of a thin Be deposit (neutron producing material) on a thin W or Mo layer to stop the beam and a Cu backing to help carry away the heat load. To achieve the adhesion of the Be films on W, Mo and Cu substrates, a powder blasting technique was applied with quartz and alumina microspheres. On the other hand, Ag deposits were made on some of the substrates previously blasted to favor the chemical affinity between Beryllium and the substrate thus improving adhesion. Be deposits were characterized by means of different techniques including Electron Microscopy (Sem) and Xr Diffraction. Roughness and thickness measurements were also made. To satisfy the power dissipation requirements for the neutron production target, a microchannel system model is proposed. The simulation based on this model permits to determine the geometric parameters of the prototype complying with the requirements of a microchannel system. Results were compared with those in several publications and discrepancies lower than 10% were found in all cases. A prototype for model validation is designed here for which simulations of fluid and structural mechanics were carried out and discussed

  3. Advancements in Tumor Targeting Strategies for Boron Neutron Capture Therapy.

    Science.gov (United States)

    Luderer, Micah John; de la Puente, Pilar; Azab, Abdel Kareem

    2015-09-01

    Boron neutron capture therapy (BNCT) is a promising cancer therapy modality that utilizes the nuclear capture reaction of epithermal neutrons by boron-10 resulting in a localized nuclear fission reaction and subsequent cell death. Since cellular destruction is limited to approximately the diameter of a single cell, primarily only cells in the neutron field with significant boron accumulation will be damaged. However, the emergence of BNCT as a prominent therapy has in large part been hindered by a paucity of tumor selective boron containing agents. While L-boronophenylalanine and sodium borocaptate are the most commonly investigated clinical agents, new agents are desperately needed due to their suboptimal tumor selectivity. This review will highlight the various strategies to improve tumor boron delivery including: nucleoside and carbohydrate analogs, unnatural amino acids, porphyrins, antibody-dendrimer conjugates, cationic polymers, cell-membrane penetrating peptides, liposomes and nanoparticles. PMID:26033767

  4. Boron neutron capture therapy of EGFR or EGFRvIII positive gliomas using either boronated monoclonal antibodies or epidermal growth factor as molecular targeting agents

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States); Barth, R.F. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States)], E-mail: rolf.barth@osumc.edu; Wu, G. [Department of Pathology, Ohio State University, 165 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210 (United States); Tjarks, W. [College of Pharmacy, Ohio State University, Columbus, OH 43210 (United States); Binns, P.; Riley, K. [Nuclear Reactor Laboratory and Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02215 (United States)

    2009-07-15

    In the present report we have summarized studies carried out over the past five years on molecular targeting of the epidermal growth factor receptor (EGFR) and its mutant isoform, EFGRvIII, for BNCT of genetically engineered F98 rat gliomas, expressing either wildtype (F98{sub EGFR}) or mutant receptors (F98{sub npEGFRvIII}). EGF or the monoclonal antibodies (mAbs), cetuximab (IMC-C225) and L8A4, which recognize wildtype EGFR and EGFRvIII, respectively, were heavily boronated using polyamidoamine (PAMAM) dendrimers (BD) linked to the targeting vehicles by means of heterobifunctional reagents. Boronated EGF or mAbs, alone or in combination with i.v. boronophenylalanine (BPA), were administered intracerebrally (i.c.) by either intratumoral (i.t.) injection or convection enhanced delivery (CED) to rats bearing F98 gliomas following which BNCT was initiated. The best survival data were obtained in rats bearing F98{sub npEGFRvIII} gliomas that had received CED of BD-L8A4 either alone or in combination with i.v. boronophenylalanine (BPA). Studies carried out in rats bearing composite tumors (F98{sub EGFR}/F98{sub npEGFRvIII}) demonstrated that it was essential to target both tumor cell populations in order to obtain an optimal therapeutic effect. Based on these observations, we have concluded that EGFR targeting vehicles are useful, but not stand-alone boron delivery agents due to the heterogeneity of receptor expression in brain tumors. They could, however, be quite useful in combination with the two drugs that currently are being used clinically, BPA and sodium borocaptate (BSH) for BNCT of either brain tumors or head and neck cancers.

  5. Boron

    International Nuclear Information System (INIS)

    The trace element boron (B) is of interest in reclamation situations for several reasons. It plays an essential through largely unidentified role in the growth of higher plants. In argronomic situations B deficiencies are common, and deficiencies in reclamation situations have been suggested but not documented. Among micronutrients, B is unique because the range from deficient concentrations to toxic concentrations either in the soil solution or in plant tissue is narrower than for any other micronutrient. In reclamation situations excessive amounts of B can occur in the soil or in near-surface mining wastes and thus interfere with reclamation objectives, especially in arid and semiarid regions. Also, B is mobile and appears subject to both upward transport (and possible contamination of overlying material) and downward transport (and possible contamination of surface water and groundwater)

  6. Elastic properties of B-C-N films grown by N2-reactive sputtering from boron carbide targets

    International Nuclear Information System (INIS)

    Boron-carbon-nitrogen films were grown by RF reactive sputtering from a B4C target and N2 as reactive gas. The films present phase segregation and are mechanically softer than boron carbide films (a factor of more than 2 in Young's modulus). This fact can turn out as an advantage in order to select buffer layers to better anchor boron carbide films on substrates eliminating thermally induced mechanical tensions

  7. Azaboranes (RNH2)B8H11NHR. A new type of boron cluster for possible use in BNCT

    International Nuclear Information System (INIS)

    This interesting group of novel, water-soluble (RNH2)B8H11NHR species can be regarded as new boron carriers with potential use in the synthesis of boron-rich compounds for application in BNCT. These azaboranes are synthesized by the reaction of B9H13(SMe2) with primary amines NH2R. (author)

  8. Halo effective field theory constrains the solar Beryllium-7 + proton -> Boron-8 + photon rate

    CERN Document Server

    Zhang, Xilin; Phillips, D R

    2015-01-01

    We report an improved low-energy extrapolation of the cross section for the process Beryllium-7+proton -> Boron-8+photon, which determines the Boron-8 neutrino flux from the Sun. Our extrapolant is derived from Halo Effective Field Theory (EFT) at next-to-leading order. We apply Bayesian methods to determine the EFT parameters and the low-energy S-factor, using measured cross sections and scattering lengths as inputs. Asymptotic normalization coefficients of Boron-8 are tightly constrained by existing radiative capture data, and contributions to the cross section beyond external direct capture are detected in the data at E < 0.5 MeV. Most importantly, the S-factor at zero energy is constrained to be S(0)= 21.3 + - 0.7 eV b, which is an uncertainty smaller by a factor of two than previously recommended. That recommendation was based on the full range for S(0) obtained among a discrete set of models judged to be reasonable. In contrast, Halo EFT subsumes all models into a controlled low-energy approximant, w...

  9. Fuzzy Logic Application in Boron and Cadmium Analysis in U3O8 use of Emission Spectrograph Method

    International Nuclear Information System (INIS)

    Boron and cadmium in U3O8 have been analyzed with emission spectrograph. Three inputs of emission spectrograph, current (A), exposure time (second) and gap between electrodes (mm) were varied. Two outputs, boron and cadmium lines intensities respectively were selected and measured. Thirteen experiments have been carried out and data found were calculated by fuzzy logic Mamdani-type. Three and five memberships functions of straight-line (Triangular, Trapezoidal), Generalized-bell and Gaussian curve were used to analyze the found data. The result found that five memberships functions had less error percentage range than three memberships functions of straight-line (Triangular, Trapezoidal), Generalized-bell and Gaussian curve. The error percentage range of cadmium analysis was wider than boron analysis with this method. Analysis of cadmium in U3O8 with this method needs much exposure time compare to analysis of boron. (author)

  10. Highly-focused boron implantation in diamond and imaging using the nuclear reaction 11B(p, α)8Be

    Science.gov (United States)

    Ynsa, M. D.; Ramos, M. A.; Skukan, N.; Torres-Costa, V.; Jakšić, M.

    2015-04-01

    Diamond is an especially attractive material because of its gemological value as well as its unique mechanical, chemical and physical properties. One of these properties is that boron-doped diamond is an electrically p-type semiconducting material at practically any boron concentration. This property makes it possible to use diamonds for multiple industrial and technological applications. Boron can be incorporated into pure diamond by different techniques including ion implantation. Although typical energies used to dope diamond by ion implantation are about 100 keV, implantations have also been performed with energies above MeV. In this work CMAM microbeam setup has been used to demonstrate capability to implant boron with high energies. An 8 MeV boron beam with a size of about 5 × 3 μm2 and a beam current higher than 500 pA has been employed while controlling the beam position and fluence at all irradiated areas. The subsequent mapping of the implanted boron in diamond has been obtained using the strong and broad nuclear reaction 11B(p, α)8Be at Ep = 660 keV. This reaction has a high Q-value (8.59 MeV for α0 and 5.68 MeV for α1) and thus is almost interference-free. The sensitivity of the technique is studied in this work.

  11. Design, development and characterization of multi-functionalized gold nanoparticles for biodetection and targeted boron delivery in BNCT applications

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Subhra [Department of Tumor Immunology, Radboud University Nijmegen Medical Centre (Netherlands); Bakeine, Gerald J., E-mail: Jamesbakeine1@yahoo.com [Department of Internal Medicine and Therapeutics-Section of Clinical Toxicology, University of Pavia, Piazza Botta 10, 27100 Pavia (Italy); Krol, Silke [Institute of Neurology, Fondazione IRCCS Carlo Besta, Milan (Italy); Ferrari, Cinzia; Clerici, Anna M.; Zonta, Cecilia; Cansolino, Laura [Department of Surgery, Laboratory of Experimental Surgery, University of Pavia (Italy); Ballarini, Francesca [Department of Nuclear and Theoretical Physics, University of Pavia (Italy); Bortolussi, Silva [Department of Nuclear and Theoretical Physics, University of Pavia (Italy)] [National Institute of Nuclear Physics (INFN), Section of Pavia (Italy); Stella, Subrina; Protti, Nicoletta [Department of Nuclear and Theoretical Physics, University of Pavia (Italy); Bruschi, Piero [National Institute of Nuclear Physics (INFN), Section of Pavia (Italy); Altieri, Saverio [Department of Nuclear and Theoretical Physics, University of Pavia (Italy)] [National Institute of Nuclear Physics (INFN), Section of Pavia (Italy)

    2011-12-15

    The aim of this study is to optimize targeted boron delivery to cancer cells and its tracking down to the cellular level. To this end, we describe the design and synthesis of novel nanovectors that double as targeted boron delivery agents and fluorescent imaging probes. Gold nanoparticles were coated with multilayers of polyelectrolytes functionalized with the fluorescent dye (FITC), boronophenylalanine and folic acid. In vitro confocal fluorescence microscopy demonstrated significant uptake of the nanoparticles in cancer cells that are known to overexpress folate receptors. - Highlights: Black-Right-Pointing-Pointer Synthesis of multi-labeled gold nanoparticles for selective boron delivery to tumor cells. Black-Right-Pointing-Pointer Tumor selectivity is achieved through folic acid receptor targeting. Black-Right-Pointing-Pointer Optical fluorescent microscopy allows tracking of cellular uptake of the gold nanoparticle. Black-Right-Pointing-Pointer In vitro tests demonstrate selective nanoparticle up in folate receptor positive tumor cells.

  12. Design, development and characterization of multi-functionalized gold nanoparticles for biodetection and targeted boron delivery in BNCT applications

    International Nuclear Information System (INIS)

    The aim of this study is to optimize targeted boron delivery to cancer cells and its tracking down to the cellular level. To this end, we describe the design and synthesis of novel nanovectors that double as targeted boron delivery agents and fluorescent imaging probes. Gold nanoparticles were coated with multilayers of polyelectrolytes functionalized with the fluorescent dye (FITC), boronophenylalanine and folic acid. In vitro confocal fluorescence microscopy demonstrated significant uptake of the nanoparticles in cancer cells that are known to overexpress folate receptors. - Highlights: ►Synthesis of multi-labeled gold nanoparticles for selective boron delivery to tumor cells. ► Tumor selectivity is achieved through folic acid receptor targeting. ► Optical fluorescent microscopy allows tracking of cellular uptake of the gold nanoparticle. ► In vitro tests demonstrate selective nanoparticle up in folate receptor positive tumor cells.

  13. New concepts for compact accelerator/target for Boron Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Two new target concepts, NIFTI and DISCOS, that enable a large reduction in the proton beam current needed to produce epithermal neutrons for BNCT (Boron Neutron Capture Therapy) are described. In the NIFTI concept, high energy neutrons produced by (p, n) reactions of 2.5 MeV protons on Li are down scattered to treatment energies (∼ 20 keV) by relatively thin layers of PbF2 and iron. In the DISCOS concept, treatment energy neutrons are produced directly in a succession of thin (∼ 1 micron) liquid Li films on rotating Be foils. These foils interact with a proton beam that operates just above threshold for the (p, n) reaction, with an applied DC field to re-accelerate the proton beam between the target foils

  14. The preparation and composition design of boron-rich lanthanum hexaboride target for sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Defang; Min, Guanghui; Wu, Yan; Yu, Huashun; Zhang, Lin, E-mail: zhanglin2007@sdu.edu.cn

    2015-07-25

    Highlights: • High-purity LaB{sub 6} powder was prepared due to significant reduction of residual B{sub 4}C and effective purification process. • The effects of raw materials ratio on the size, morphology, phase structure and crystalline size of LaB{sub 6} were studied. • The correlation of component between LaB{sub 6} films and boron-rich targets was established. • The variation of densities of LaB{sub 6} targets with sintering time and sintering temperature was investigated. - Abstract: Lanthanum Hexaboride (LaB{sub 6}) nano-film has been proved to be promising transparent thermal insulation material, while its properties are limited on purity and composition. High-purity LaB{sub 6} polycrystalline powder was prepared through boron carbide reduction method in this work. A series of techniques such as scanning electron microscopy, X-ray diffraction, laser particle analyzer and inductively coupled plasma emission spectrometer were employed to characterize LaB{sub 6} powder. As raising the content of La{sub 2}O{sub 3} in reactants, more uniform, finer (2.686 μm) and purer (99.5139 wt%) LaB{sub 6} powder is prepared, with only 0.4434 wt% residual B{sub 4}C. The density of targets increases with the rise of sintering temperature and the extension of sintering time, while crystallite size increases simultaneously with the extension of sintering time. The introduction of B powder in target is conductive to sintering process, increasing hardness and flexural strength of targets. X-ray photoelectron spectrometer was used to characterize the composition and microstructure of LaB{sub 6} nano-film which is tentatively considered to be composed of LaB{sub 6} nanocrystalline and amorphous microstructure of La and B atoms. The film LaB{sub 6.0627±0.02} was obtained when the ratio of B and La of sputtering target reached 12.5. The thickness and deposition rate decrease with the increase of B content in targets.

  15. Proton- and -radiation of the Micro-Pinch with the Boron-Containing Target

    Directory of Open Access Journals (Sweden)

    Anatolii A. Gurin

    2013-01-01

    Full Text Available Using ion pinhole camera and track detectors, the image of hot spot is recorded in a pulsed diode micro-pinch equipped with a solid anode target. The track image is a record of repeated fronts of fast protons with energies up to 1 MeV. Fluctuations in the ion luminosity of hot spot are associated with the wave-like nature of the proton accelerating processes in the dense plasma of target material, which is characterized by a mean energy of 100 keV. The results of the track analysis of a fast ions, detected in the Thomson analyser in experiments with boron-polyethylene targets, are presented. In 5% of the shots, the presence of ?-particles of energy up to 2 MeV in the flux of fast ions is discovered by means of Thomson analyser equipped with track detectors. Estimations of total amount of helium nuclei as products of nuclear reactions p(B11, 2? result in an output of 108 ÷ 109 per successive shot.

  16. B4C solid target boronization of the MST reversed-field pinch

    International Nuclear Information System (INIS)

    A solid rod of hot-pressed boron carbide is being used as the source of boron during boronization of MST. The most striking result of this procedure is the reduction in oxygen contamination of the plasma (O III radiation, characteristic of oxygen at the edge, falls by about a factor of 3 after boronization.). The radiated power fraction drops to about half its initial value. Particle reflux from the wall is also lowered, making density control simpler. The rod (12.7 mm diameter) is inserted into the edge plasma of normal high-power RFP discharges. B4C is ablated from the surface of the rod and deposited in a thin film (a-B/C:H) on the walls and limiters. The energy flux carried by ''superthermal'' (not ''runaway'') electrons at the edge of MST appears to enhance the efficient, non-destructive ablation of the boron carbide rod

  17. Boron enrichment by ion exchange with Dowex 1X8 anion resin

    International Nuclear Information System (INIS)

    An isotopic separation pilot plant with five ion exchange columns interconnected in series were designed and built in the IEN. The boric acid solution is introduced in the separation columns until it reaches a absorbing zone lenght which is sufficient to obtain the desired boron-10 isotopic concentration. The boric acid absorbing zone movement is provided by the injection of a diluted hydrochloric acid solution, which replces the boric acid troughout the columns to its total lenght. The enriched boron-10 and the depleted boron are located in the final boundary and in the initial position of the absorbing zones, respectively. (author). 6 refs

  18. 22 CFR 139.8 - Target economic sectors.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Target economic sectors. 139.8 Section 139.8... § 139.8 Target economic sectors. Job/Training under the IPPCTP will be authorized for preferred economic... authorized to approve different employers in different economic sectors....

  19. Synthesis and Transformations of 5-Chloro-2,2′-Dipyrrins and Their Boron Complexes, 8-Chloro-BODIPYs**

    OpenAIRE

    Wang, Haijun; Vicente, M. Graça H.; Frank R. Fronczek; Smith, Kevin M.

    2014-01-01

    Symmetric dipyrrylketones 1a,b were synthesized in two steps from the corresponding α-free pyrroles, by reaction with thiophosgene followed by oxidative hydrolysis under basic conditions. The dipyrrylketones produced the corresponding 5-chloro-dipyrrinium salts or 5-ethoxy-dipyrrins on reaction with phosgene or Meerwein’s salt, respectively. Boron complexation of the dipyrrins afforded the corresponding 8-functionalized BODIPYs (borondipyrromethenes) in high yields. The 5-chloro-dipyrrinium s...

  20. Synthesis and transformations of 5-chloro-2,2'-dipyrrins and their boron complexes, 8-chloro-BODIPYs.

    Science.gov (United States)

    Wang, Haijun; Vicente, M Graça H; Fronczek, Frank R; Smith, Kevin M

    2014-04-22

    Symmetric dipyrrylketones 1 a,b were synthesized in two steps from the corresponding α-free pyrroles, by reaction with thiophosgene followed by oxidative hydrolysis under basic conditions. The dipyrrylketones produced the corresponding 5-chloro-dipyrrinium salts or 5-ethoxy-dipyrrins on reaction with phosgene or Meerwein's salt, respectively. Boron complexation of the dipyrrins afforded the corresponding 8-functionalized BODIPYs (borondipyrromethenes) in high yields. The 5-chloro-dipyrrinium salts reacted with methoxide or ethoxide ions to produce monopyrrole esters, presumably via a 5,5-dialkoxy-dipyrromethane intermediate. In contrast, 8-chloro-BODIPYs underwent a variety of nucleophilic substitutions of the chloro group in the presence of alkoxide ions, Grignard reagents, and thiols. In the presence of excess alkoxide or Grignard reagent, at room temperature or above, substitution at the boron center also occurred. The 8-chloro-BODIPY was a particularly useful reagent for the preparation of 8-aryl-, 8-alkyl-, and 8-vinyl-substituted BODIPYs in very high yields, using Pd(0) -catalyzed Stille cross-coupling reactions. The X-ray structures of eleven BODIPYs and two pyrroles are presented, and the spectroscopic properties of the synthesized BODIPYs are discussed. PMID:24616111

  1. Neutron capture therapy of epidermal growth factor receptor (EGFR)vIII positive gliomas using boronated monoclonal antibody L8A4

    International Nuclear Information System (INIS)

    The purpose of the present study was to evaluate the EGFRvIII specific monoclonal antibody, L8A4 as a boron delivery agent for NCT of the receptor (+) rat glioma, F98npEGFRvIII. A heavily boronated polyamidoamine (PAMAM) dendrimer (BD) was linked to L8A4 by means of heterobifunctional reagents. Wild type (F98WT) receptor(-) or EGFRvIII human gene transfected receptor(+) F98npEGFRvIII glioma cells were implanted into the brains of Fischer rats. Biodistribution studies were initiated 14 d later. Animals received 125I-labeled BD-L8A4 by either convection enhanced delivery (CED) or intratumoral(i.t.) injection and were euthanized 6, 12, 24 or 48 h later. At 6 h following CED, equivalent amounts of the bioconjugate were detected in receptor(+) and (-) tumors, but by 24 h the amounts retained by receptor(+) gliomas were 60.1% following CED and 43.7% following i.t. injection, compared to 14.6% ID/g by receptor(-) tumors. Tumor boron concentrations were 32.7 and 44.5 μg/g, respectively, for BD-L8A4 alone or in combination with i.v. BPA. BNCT was carried out at the MITR-II Reactor 24 h after CED of BD-L8A4 (∼40 μg 10B/∼750 μg protein) and 2.5 h after i.v. injection of BPA (500 mg/kg). Rats that received BD-L8A4 alone or in combination with BPA had mean survival times of 70.4 and 85d, respectively, with 20% and 10% long term survivors, respectively, compared to 40.1 d for i.v. BPA and 30.3 and 26.3 d for irradiated and untreated controls, respectively. These data convincingly demonstrate the therapeutic efficacy of molecular targeting of EGFRvIII and should provide a platform for the future development of combinations of high and low molecular weight delivery agents for BNCT of brain tumors. (author)

  2. Boron-proton nuclear-fusion enhancement induced in boron-doped silicon targets by low-contrast pulsed laser

    Czech Academy of Sciences Publication Activity Database

    Picciotto, A.; Margarone, Daniele; Velyhan, Andriy; Bellutti, P.; Krása, Josef; Szydlowsky, A.; Bertuccio, G.; Shi, Y.; Mangione, A.; Prokůpek, Jan; Malinowska, A.; Krouský, Eduard; Ullschmied, Jiří; Láska, Leoš; Kucharik, M.; Korn, Georg

    2014-01-01

    Roč. 4, č. 3 (2014), "031030-1"-"031030-8". ISSN 2160-3308 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk(CZ) LD14089; GA MŠk LM2010014 Grant ostatní: ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; AVČR(CZ) M100101210; FP7 Laserlab Europe(XE) 284464 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : thermonuclear fusion * fast ions * plasmas * energy * acceleration * hydrogen * detector Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BL - Plasma and Gas Discharge Physics (UFP-V) Impact factor: 9.043, year: 2014

  3. High sensitivity boron quantification in bulk silicon using the 11B(p,α0)8Be nuclear reaction

    International Nuclear Information System (INIS)

    There is a great need to quantify sub-ppm levels of boron in bulk silicon. There are several methods to analyze B in Si: Nuclear Reaction Analysis using the 11B(p,α0)8Be reaction exhibits a quantification limit of some hundreds ppm of B in Si. Heavy Ion Elastic Recoil Detection Analysis offers a detection limit of 5 to 10 at. ppm. Secondary Ion Mass Spectrometry is the method of choice of the semiconductor industry for the analysis of B in Si. This work verifies the use of NRA to quantify B in Si, and the corresponding detection limits. Proton beam with 1.6 up to 2.6 MeV was used to obtain the cross-section of the 11B(p,α0)8Be nuclear reaction at 170° scattering angle. The results show good agreementwith literature indicating that the quantification of boron in silicon can be achieved at 100 ppm level (high sensitivity) at LAMFI-IFUSP with about 16% uncertainty. Increasing the detection solid angle and the collected beam charge, can reduce the detection limit to less than 100 ppm meeting present technological needs.

  4. TRPM8: a potential target for cancer treatment.

    Science.gov (United States)

    Liu, Zhaoguo; Wu, Hongyan; Wei, Zhonghong; Wang, Xu; Shen, Peiliang; Wang, Siliang; Wang, Aiyun; Chen, Wenxing; Lu, Yin

    2016-09-01

    Transient receptor potential (TRP) cation channel superfamily plays critical roles in variety of processes, including temperature perception, pain transduction, vasorelaxation, male fertility, and tumorigenesis. One of seven families within the TRP superfamily of ion channels, the melastatin, or TRPM family comprises a group of eight structurally and functionally diverse channels. Of all the members of TRPM subfamily, TRPM8 is the most notable one. A lot of literatures have demonstrated that transient receptor potential melastatin 8 (TRPM8) could perform a myriad of functions in vertebrates and invertebrates alike. In addition to its well-known function in cold sensation, TRPM8 has an emerging role in a variety of biological systems, including thermoregulation, cancer, bladder function, and asthma. Recent studies have shown that TRPM8 is necessary to the initiation and progression of tumors, and the aberrant expression of TRPM8 was found in varieties of tumors, such as prostate tumor, melanoma, breast adenocarcinoma, bladder cancer, and colorectal cancer, making it a novel molecular target potentially useful in the diagnosis and treatment of cancer. This review outlines our current understanding on the role of TRPM8 in occurrence and development of different kinds of tumor and also includes discussion about the regulation of TRPM8 during carcinogenesis as well as therapeutic potential of targeting TRPM8 in tumor, which may be utilized for a potential pharmacological use as a target for anti-cancer therapy. PMID:26803314

  5. New targets in plant boron deficiency response: Nglycosylation and regulation of root developement

    OpenAIRE

    Abreu Sánchez, Isidro

    2016-01-01

    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología   Since Warington described in 1923 for first time boron (B) essentiality in plants, many authors have tried to understand what the micronutrient is doing, how the micronutrient is acquired, and what happens when the micronutrient is absent. First studies on B nutrition focused on physiological processes and biochemical pathways which appeared altered as a consequence of B d...

  6. Targets downstream of Cdk8 in Dictyostelium development

    Directory of Open Access Journals (Sweden)

    Skelton Jason

    2011-01-01

    Full Text Available Abstract Background Cdk8 is a component of the mediator complex which facilitates transcription by RNA polymerase II and has been shown to play an important role in development of Dictyostelium discoideum. This eukaryote feeds as single cells but starvation triggers the formation of a multicellular organism in response to extracellular pulses of cAMP and the eventual generation of spores. Strains in which the gene encoding Cdk8 have been disrupted fail to form multicellular aggregates unless supplied with exogenous pulses of cAMP and later in development, cdk8- cells show a defect in spore production. Results Microarray analysis revealed that the cdk8- strain previously described (cdk8-HL contained genome duplications. Regeneration of the strain in a background lacking detectable gene duplication generated strains (cdk8-2 with identical defects in growth and early development, but a milder defect in spore generation, suggesting that the severity of this defect depends on the genetic background. The failure of cdk8- cells to aggregate unless rescued by exogenous pulses of cAMP is consistent with a failure to express the catalytic subunit of protein kinase A. However, overexpression of the gene encoding this protein was not sufficient to rescue the defect, suggesting that this is not the only important target for Cdk8 at this stage of development. Proteomic analysis revealed two potential targets for Cdk8 regulation, one regulated post-transcriptionally (4-hydroxyphenylpyruvate dioxygenase (HPD and one transcriptionally (short chain dehydrogenase/reductase (SDR1. Conclusions This analysis has confirmed the importance of Cdk8 at multiple stages of Dictyostelium development, although the severity of the defect in spore production depends on the genetic background. Potential targets of Cdk8-mediated gene regulation have been identified in Dictyostelium which will allow the mechanism of Cdk8 action and its role in development to be determined.

  7. Tumor-targeted boron-containing amino acids and their related compounds. Synthesis and biological activity

    International Nuclear Information System (INIS)

    In a series of our synthetic studies on boron-containing amino acids and their related compounds for BNCT (Boron Neutron Capture Therapy), p-boronophenylalanine (BPA), p-boronophenylserine (BPS), o-carboranylmethyl-3-hydroxytyrosine (CMHT) and their derivatives were designed and synthesized by using of isocyano compounds as a starting material. Two water-soluble amino alcohols, BPA-OH and BPS-OH, were prepared by the reduction of the corresponding N-formyl amino esters. On the other hand, CMHTA, an amide derivative of CMHT, was synthesized by an aldol-type condensation of isocyanoacetamide with 4-(o-carboranylmethyloxy)benz aldehyde as a key reaction. The relative tumor cell (human glioma T98G) killing effect of nBPS-OH, nBPA-OH and CMHTA against 10BPA was 0.7, 1.0 and 4.9, respectively. The uptake of CMHTA by the tumor cell increased with increasing cultivation time. (J.P.N.)

  8. Proton induced gamma-ray production cross sections and thick-target yields for boron, nitrogen and silicon

    Science.gov (United States)

    Marchand, Benoît; Mizohata, Kenichiro; Räisänen, Jyrki

    2016-07-01

    The excitation functions for the reactions 14N(p,p‧γ)14N, 28Si(p,p‧γ)28Si and 29Si(p,p‧γ)29Si were measured at an angle of 55° by bombarding a thin Si3N4 target with protons in the energy range of 3.6-6.9 MeV. The deduced γ-ray production cross section data is compared with available literature data relevant for ion beam analytical work. Thick-target γ-ray yields for boron, nitrogen and silicon were measured at 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5 MeV proton energies utilizing thick BN and Si3N4 targets. The measured yield values are put together with available yield data found in the literature. The experimental yield data has been used to cross-check the γ-ray production cross section values by comparing them with calculated thick-target yields deduced from the present and literature experimental excitation curves. All values were found to be in reasonable agreement taking into account the experimental uncertainties.

  9. Sputtering behavior of boron and boron carbide

    International Nuclear Information System (INIS)

    Sputtering yields of boron were measured with D+ and B+ ions for normal and oblique angles of incidence. Self-sputtering data of boron carbide were simulated in the experiment by using Ne+ ions. The energies of the impinging ions were between 20 eV and 10 keV. The measured data are compared with computer simulated values calculated with the TRIMSP program. The boron data for normal ion impact are higher than the calculated values, whereas those for oblique ion incidence are smaller than the calculation predicts. This discrepancy is explained by the surface roughness and supported by SEM micrographs. The comparison of the boron carbide data with TRIMSP calculations shows much better agreement than the boron data. In this case the target surface was much smoother. (orig.)

  10. A comparative study of 30MeV boron4+ and 60MeV oxygen8+ ion irradiated Si NPN BJTs

    International Nuclear Information System (INIS)

    The impact of 30MeV boron4+ and 60MeV oxygen8+ ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor

  11. A comparative study of 30MeV boron{sup 4+} and 60MeV oxygen{sup 8+} ion irradiated Si NPN BJTs

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. Vinay, E-mail: Vkm288@gmail.com; Krishnaveni, S. [Department of studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Yashoda, T. [Deparment of Physics, AVK College for women, Hassan-573201 (India); Dinesh, C. M. [Department of Physics, Govt. First grade college for women, Chintamani-563125 (India); Krishnakumar, K. S. [Department of Physics, APS College of Engineering (India); Jayashree, B. [Department of Physics, Maharanis Science College for Women, Bangalore-560001 (India); Ramani [Department of Physics, Bangalore University, Jnanabharathi, Bangalore-560056 (India)

    2015-06-24

    The impact of 30MeV boron{sup 4+} and 60MeV oxygen{sup 8+} ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor.

  12. Magnetron sputter deposition of boron and boron carbide

    International Nuclear Information System (INIS)

    The fabrication of X-ray optical coatings with greater reflectivity required the development of sputter deposition processes for boron and boron carbide. The use of high density boron and boron carbide (B4C) and a vacuum-brazed target design was required to achieve the required sputter process stability and resistance to the thermal stress created by high rate sputtering. Our results include a description of the target fabrication procedures and sputter process parameters necessary to fabricate B4C and boron modulated thin film structures. (orig.)

  13. Crystal structure of bis(3-bromomesityl)(quinolin-1-ium-8-yl)boron(III) tribromide

    OpenAIRE

    Jungho Son; Sem Raj Tamang; Hoefelmeyer, James D.

    2015-01-01

    The title compound, C27H26.82BBr2.18N+·Br3−, is a cationic triarylborane isolated as its tribromide salt. The aryl substituents include a protonated 8-quinolyl group and two 3-bromomesityl groups. The molecule was prepared on combination of 3:1 Br2 and dimesityl(quinolin-8-yl)borane in hexanes. The refinement of the structure indicated a degree of `over-bromination' (beyond two bromine atoms) for the cation. There are two tribromide ions in the asymmetric unit, both completed by crystallograp...

  14. How well do we understand Beryllium-7 + proton -> Boron-8 + photon? An Effective Field Theory perspective

    CERN Document Server

    Zhang, Xilin; Phillips, D R

    2015-01-01

    We have studied the 7Be(p,photon)8B reaction in the Halo effective field theory (EFT) framework. The leading order (LO) results were published in Phys.Rev.C89,051602(2014) after the isospin mirror process, 7Li(n,photon)8Li, was addressed in Phys.Rev.C89,024613(2014). In both calculations, one key step was using the final shallow bound state asymptotic normalization coefficients (ANCs) computed by ab initio methods to fix the EFT couplings. Recently we have developed the next-to-LO (NLO) formalism (to appear soon), which could reproduce other model results by no worse than 1% when the 7Be-p energy was between 0 and 0.5 MeV. In our recent report (arXiv:1507.07239), a different approach from that in Phys.Rev.C89,051602(2014) was used. We applied Bayesian analysis to constrain all the NLO-EFT parameters based on measured S-factors, and found tight constraints on the S-factor at solar energies. Our S(E=0 MeV)= 21.3 + - 0.7 eV b. The uncertainty is half of that previously recommended. In this proceeding, we provide...

  15. Intracellular targeting of mercaptoundecahydrododecaborate (BSH) to malignant glioma by transferrin-PEG liposomes for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    Malignant glioma is one of the most difficult tumor to control with usual therapies. In our institute, we select boron neutron capture therapy (BNCT) as an adjuvant radiation therapy after surgical resection. This therapy requires the selective delivery of high concentration of 10B to malignant tumor tissue. In this study, we focused on a tumor-targeting 10B delivery system (BDS) for BNCT that uses transferrin-conjugated polyethylene-glycol liposome encapsulating BSH (TF-PEG liposome-BSH) and compared 10B uptake of the tumor among BSH, PEG liposome-BSH and TF-PEG liposome-BSH. In vitro, we analyzed 10B concentration of the cultured human U87Δ glioma cells incubated in medium containing 20 μg 10B/ml derived from each BDS by inductively coupled plasma atomic emission spectrometry (ICP-AES). In vivo, human U87Δ glioma-bearing nude mice were administered with each BDS (35mg 10B/kg) intravenously. We analyzed 10B concentration of tumor, normal brain and blood by ICP-AES. The TF-PEG liposome-BSH showed higher absolute concentration more than the other BDS. Moreover, TF-PEG liposome-BSH decreased 10B concentration in blood and normal tissue while it maintained high 10B concentration in tumor tissue for a couple of days. This showed the TF-PEG liposome-BSH caused the selective delivery of high concentration of 10B to malignant tumor tissue. The TF-PEG liposome-BSH is more potent BDS for BNCT to obtain absolute high 10B concentration and good contrast between tumor and normal tissue than BSH and PEG liposome-BSH. (author)

  16. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: halfon@phys.huji.ac.il; Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Steinberg, D. [Biofilm Laboratory, Institute of Dental Sciences, Faculty of Dentistry, Hebrew University-Hadassah (Israel); Nagler, A.; Arenshtam, A.; Kijel, D. [Soreq NRC, Yavne 81800 (Israel); Polacheck, I. [Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center (Israel); Srebnik, M. [Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University, Jerusalem 91120 (Israel)

    2009-07-15

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction {sup 7}Li(p,n){sup 7}Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  17. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases

    International Nuclear Information System (INIS)

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction 7Li(p,n)7Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  18. Boron concentrations in brain during boron neutron capture therapy: in vivo measurements from the Phase I trial EORTC 11961 using a gamma-ray telescope

    International Nuclear Information System (INIS)

    Purpose: Gamma-ray spectroscopic scans to measure boron concentrations in the irradiated volume were performed during treatment of 5 patients suffering from brain tumors with boron neutron capture therapy (BNCT). In BNCT, the dose that is meant to be targeted primarily to the tumor is the dose coming from the reaction 10B(n,α)7Li, which is determined by the boron concentration in tissue and the thermal neutron fluence rate. The boron distribution throughout the head of the patient during the treatment is therefore of major interest. The detection of the boron distribution during the irradiation was until now not possible. Methods and Materials: Five patients suffering from glioblastoma multiforme and treated with BNCT in a dose escalation study were administered the boron compound, boron sulfhydryl (BSH; Na2B12H11SH). Boron concentrations were reconstructed from measurements performed with the gamma-ray telescope which detects locally the specific gamma rays produced by neutron capture in 10B and 1H. Results: For all patients, at a 10B concentration in blood of 30 ppm, the boron concentration in nonoperated areas of the brain was very low, between 1 and 2.5 ppm. In the target volume, which included the area where the tumor had been removed and where remaining tumor cells have to be assumed, much higher boron concentrations were measured with large variations from one patient to another. Superficial tissue contained a higher concentration of 10B than the nonoperated areas of the brain, ranging between 8 and 15 ppm. Conclusions: The measured results correspond with previous tissue uptake studies, confirming that normal brain tissue hardly absorbs the boron compound BSH. Gamma-ray telescope measurements seem to be a promising method to provide information on the biodistribution of boron during therapy. Furthermore, it also opens the possibility of in vivo dosimetry

  19. Interpenetration of a 3D Icosahedral M@Ni12 (M=Al, Ga) Framework with Porphyrin-Reminiscent Boron Layers in MNi9 B8.

    Science.gov (United States)

    Zheng, Qiang; Wagner, Frank R; Ormeci, Alim; Prots, Yurii; Burkhardt, Ulrich; Schmidt, Marcus; Schnelle, Walter; Grin, Yuri; Leithe-Jasper, Andreas

    2015-11-01

    Two ternary borides MNi9 B8 (M=Al, Ga) were synthesized by thermal treatment of mixtures of the elements. Single-crystal X-ray diffraction data reveal AlNi9 B8 and GaNi9 B8 crystallizing in a new type of structure within the space group Cmcm and the lattice parameters a=7.0896(3) Å, b=8.1181(3) Å, c=10.6497(4) Å and a=7.0897(5) Å, b=8.1579(4) Å, c=10.6648(7) Å, respectively. The boron atoms build up two-dimensional layers, which consist of puckered [B16 ] rings with two tailing B atoms, whereas the M atoms reside in distorted vertices-condensed [Ni12 ] icosahedra, which form a three-dimensional framework interpenetrated by boron porphyrin-reminiscent layers. An unusual local arrangement resembling a giant metallo-porphyrin entity is formed by the [B16 ] rings, which, due to their large annular size of approximately 8 Å, chelate four of the twelve icosahedral Ni atoms. An analysis of the chemical bonding by means of the electron localizability approach reveals strong covalent B-B interactions and weak Ni-Ni interactions. Multi-center dative B-Ni interaction occurs between the Al-Ni framework and the boron layers. In agreement with the chemical bonding analysis and band structure calculations, AlNi9 B8 is a Pauli-paramagnetic metal. PMID:26418894

  20. National Ignition Facility subsystem design requirements target positioning subsystem SSDR 1.8.2

    International Nuclear Information System (INIS)

    This Subsystem Design Requirement document is a development specification that establishes the performance, design, development and test requirements for the target positioner subsystem (WBS 1.8.2) of the NIF Target Experimental System (WBS 1.8)

  1. Targeting CD8 T-Cell Metabolism in Transplantation

    OpenAIRE

    Yap, Michelle; Brouard, Sophie; Pecqueur, Claire; Degauque, Nicolas

    2015-01-01

    Infiltration of effector CD8 T cells plays a major role in allograft rejection, and increases in memory and terminally differentiated effector memory CD8 T cells are associated with long-term allograft dysfunction. Alternatively, CD8 regulatory T cells suppress the inflammatory responses of effector lymphocytes and induce allograft tolerance in animal models. Recently, there has been a renewed interest in the field of immunometabolics and its important role in CD8 function and differentiation...

  2. Transferrin-loaded nido-carborane liposomes. Synthesis and intracellular targeting to solid tumors for boron neutron capture therapy

    International Nuclear Information System (INIS)

    The boron ion cluster lipids, as a double-tailed boron lipid synthesized from heptadecanol, formed stable liposomes at 25% molar ratio toward DSPC with cholesterol. Transferrin was able to be introduced on the surface of boron liposomes (Tf-PEG-CL liposomes) by the coupling of transferrin to the PEG-CO2H moieties of PEG-CL liposomes. The biodistribution of Tf-PEG-CL liposomes showed that Tf-PEG-CL liposomes accumulated in tumor tissues and stayed there for a sufficiently long time to increase tumor:blood concentration ratio. A 10B concentration of 22 ppm in tumor tissues was achieved by the injection of Tf-PEG-CL liposome at 7.2 mg/kg body weight 10B in tumor-bearing mice. After neutron irradiation, the average survival rate of mice not treated with Tf-PEG-CL liposomes was 21 days, whereas that of the treated mice was 31 days. Longer survival rates were observed in the mice treated with Tf-PEG-CL liposomes; one of them even survived for 52 days after BNCT. (author)

  3. National Ignition Facility subsystem design requirements target area auxiliary subsystem SSDR 1.8.6

    International Nuclear Information System (INIS)

    This Subsystem Design Requirement (SSDR) establishes the performance, design, development, and test requirements for the Target Area Auxiliary Subsystems (WBS 1.8.6), which is part of the NIF Target Experimental System (WBS 1.8). This document responds directly to the requirements detailed in NIF Target Experimental System SDR 003 document. Key elements of the Target Area Auxiliary Subsystems include: WBS 1.8.6.1 Local Utility Services; WBS 1.8.6.2 Cable Trays; WBS 1.8.6.3 Personnel, Safety, and Occupational Access; WBS 1.8.6.4 Assembly, Installation, and Maintenance Equipment; WBS 1.8.6.4.1 Target Chamber Service System; WBS 1.8.6.4.2 Target Bay Service Systems

  4. High sensitivity boron quantification in bulk silicon using the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Moro, Marcos V.; Silva, Tiago F. da; Added, Nemitala; Rizutto, Marcia A.; Tabacniks, Manfredo H. [Instituto de Fisica da Universidade de Sao Paulo, C.P. 66318, 05315-970 Sao Paulo, SP (Brazil); Neira, John B.; Neto, Joao B. F. [Institute of Research Tecnology, Cidade Universitaria, SP, 05508-091 (Brazil)

    2013-05-06

    There is a great need to quantify sub-ppm levels of boron in bulk silicon. There are several methods to analyze B in Si: Nuclear Reaction Analysis using the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be reaction exhibits a quantification limit of some hundreds ppm of B in Si. Heavy Ion Elastic Recoil Detection Analysis offers a detection limit of 5 to 10 at. ppm. Secondary Ion Mass Spectrometry is the method of choice of the semiconductor industry for the analysis of B in Si. This work verifies the use of NRA to quantify B in Si, and the corresponding detection limits. Proton beam with 1.6 up to 2.6 MeV was used to obtain the cross-section of the {sup 11}B(p,{alpha}{sub 0}){sup 8}Be nuclear reaction at 170 Degree-Sign scattering angle. The results show good agreementwith literature indicating that the quantification of boron in silicon can be achieved at 100 ppm level (high sensitivity) at LAMFI-IFUSP with about 16% uncertainty. Increasing the detection solid angle and the collected beam charge, can reduce the detection limit to less than 100 ppm meeting present technological needs.

  5. Near barrier scattering of 8He from heavy targets

    OpenAIRE

    Marquínez Durán, Gloria

    2016-01-01

    The objective of this thesis is the study of the elastic scattering of 8He from 208Pb at energies around the Coulomb barrier. This work is an extension of the investigations performed by the collaboration, in which the Grupo de Estructura de la Materia of the University of Huelva takes part, on 6He reactions at near-barrier energies. The direct comparison of the experimental data from the 6He+208Pb and 8He+208Pb experiments will allow for studying the subtle differences in the dynamics of hal...

  6. 13 CFR 124.509 - What are non-8(a) business activity targets?

    Science.gov (United States)

    2010-01-01

    ... reasonable marketing strategy, to attain the targeted dollar levels of non-8(a) revenue established in its..., business development, financing, marketing, accounting, or proposal preparation. (5) SBA may...

  7. National Ignition Facility subsystem design requirements target diagnostics subsystem SSDR 1.8.3

    International Nuclear Information System (INIS)

    This SSDR establishes the performance, design, development and test requirements for the Target Experimental System's Diagnostic, WBS 1.8. 3. This includes the individual diagnostic components, the Target Diagnostic Data Acquisition System (Target DAS), the diagnostic vacuum system, the timing/fiducial system, and the EMI protection system

  8. Electroextraction of boron from boron carbide scrap

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Ashish [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Anthonysamy, S., E-mail: sas@igcar.gov.in [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Ghosh, C. [Physical Metallurgy Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Ravindran, T.R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Divakar, R.; Mohandas, E. [Physical Metallurgy Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India)

    2013-10-15

    Studies were carried out to extract elemental boron from boron carbide scrap. The physicochemical nature of boron obtained through this process was examined by characterizing its chemical purity, specific surface area, size distribution of particles and X-ray crystallite size. The microstructural characteristics of the extracted boron powder were analyzed by using scanning electron microscopy and transmission electron microscopy. Raman spectroscopic examination of boron powder was also carried out to determine its crystalline form. Oxygen and carbon were found to be the major impurities in boron. Boron powder of purity ∼ 92 wt. % could be produced by the electroextraction process developed in this study. Optimized method could be used for the recovery of enriched boron ({sup 10}B > 20 at. %) from boron carbide scrap generated during the production of boron carbide. - Highlights: • Recovery of {sup 10}B from nuclear grade boron carbide scrap • Development of process flow sheet • Physicochemical characterization of electroextracted boron • Microscopic examination of electroextracted boron.

  9. Electroextraction of boron from boron carbide scrap

    International Nuclear Information System (INIS)

    Studies were carried out to extract elemental boron from boron carbide scrap. The physicochemical nature of boron obtained through this process was examined by characterizing its chemical purity, specific surface area, size distribution of particles and X-ray crystallite size. The microstructural characteristics of the extracted boron powder were analyzed by using scanning electron microscopy and transmission electron microscopy. Raman spectroscopic examination of boron powder was also carried out to determine its crystalline form. Oxygen and carbon were found to be the major impurities in boron. Boron powder of purity ∼ 92 wt. % could be produced by the electroextraction process developed in this study. Optimized method could be used for the recovery of enriched boron (10B > 20 at. %) from boron carbide scrap generated during the production of boron carbide. - Highlights: • Recovery of 10B from nuclear grade boron carbide scrap • Development of process flow sheet • Physicochemical characterization of electroextracted boron • Microscopic examination of electroextracted boron

  10. Optical and electronic properties of SO2 molecule adsorbed on Si-doped (8, 0) boron nitride nanotube

    Science.gov (United States)

    Guo, Shuang-Shuang; Wei, Xiu-Mei; Zhang, Jian-Min; Zhu, Gang-Qiang; Guo, Wan-Jin

    2016-09-01

    The study of the optical properties of pristine BNNT, Si-doped BNNTs and SO2 molecule adsorption on Si-doped BNNTs is that, to our knowledge, few relevant research have ever been found. In this paper, the adsorption behaviors of Sulfur dioxide (SO2) molecule on Si-doped Boron nitride nanotubes (BNNTs) are investigated applying the first-principles calculations. The main contribution of this paper is that the foremost investigation for the optical properties of the pristine BNNT, Si-doped BNNTs and SO2 adsorption on Si-doped BNNTs. Additionally, the electronic properties and the structural properties are also presented. In our calculations of optical properties, the dielectric constant, the refractive index and the absorption coefficient are obtained. Comparing the pristine BNNT, our results indicate that, the blue-shifts (in the main peaks of the dielectric constant of SiB -BNNT and SO2-SiB -BNNT), and the red-shifts (in the main peaks of the refractive index of SiN -BNNT and SO2-SiN -BNNT) are appeared. Under these conditions, Si-doped BNNT and Si-doped BNNT with SO2 adsorption, the gaps are reduced both for the speculated optical band gaps and the electronic structure band gaps.

  11. Edge and substrate-induced bandgap in zigzag graphene nanoribbons on the hexagonal nitride boron 8-ZGNR/h-BN(0001

    Directory of Open Access Journals (Sweden)

    V. V. Ilyasov

    2013-09-01

    Full Text Available The results of DFT (GGA-PBEsol and DFT(PBE-D2 study of the band structure of zigzag graphene nanoribbons on hexagonal nitride boron 8-ZGNR/h-BN(0001 are presented, suitable as potential base for new materials for spintronics. It offers a study of regularities in the changes of the valence band electron structure and the induction of the energy gap in the series 8-ZGNR → 8-ZGNR/h-BN(0001 → graphene/h-BN(0001. The peculiarities of the spin state at the Fermi level, the roles of the edge effect and the effect of substrate in formation of the band gap in 8-ZGNR/h-BN(0001 system are discussed. Our calculations shown that vdW-correction plays an important role in the adsorption of GNR on h-BN and results in reduction of the interplanar distances in equilibrium systems ZGNRs/h-BN(0001. As a result of the structural changes we have obtained new values of the energy gap in the 8-ZGNR-AF and 8-ZGNR-AF/h-BN(0001 systems. The paper demonstrates appearance of 600 meV energy gap in the 8-ZGNR/h-BN(0001 interface. The contributions of nanoribbon edges and the substrate in formation of the gap have been differentiated for the first time. The estimations of local magnetic moments on carbon atoms are made. Shown that in case of ferromagnetic ordering substrate presense causes insignificant splitting of the bands. The splitting reached only (14-28 meV. Since the electronic states of a suspended GNR in point (k=π are degenerate near the Fermi level, we can assume that the above splitting in 8-ZGNR/h-BN(0001 is only determined by the contribution of the h-BN(0001 substrate.

  12. Synthesis and characterization of boron incorporated diamond-like carbon thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.L. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Yang, Q., E-mail: qiaoqin.yang@usask.ca [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Tang, Y.; Yang, L.; Zhang, C. [Department of Mechanical Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9 (Canada); Hu, Y.; Cui, X. [Canadian Light Source Inc., 101 Perimeter Road, Saskatoon, SK S7N 0X4 (Canada)

    2015-08-31

    Boron incorporated diamond-like carbon (B-DLC) (up to 8 wt.% boron) thin films were synthesized on silicon wafers using biased target ion beam deposition technique, where diamond-like carbon (DLC) was deposited by ion beam deposition and boron (B) was simultaneously incorporated by biased target sputtering of a boron carbide (B{sub 4}C) target under different conditions. Pure DLC films and B–C films were also synthesized by ion beam deposition and biased target sputtering of B{sub 4}C under similar conditions, respectively, as reference samples. The microstructure and mechanical properties of the synthesized films have been characterized by various technologies. It has been found that B exists in different states in B-DLC, including carbon-rich and B-rich boron carbides, boron suboxide and boron oxide, and the oxidation of B probably occurs during the film deposition. The incorporation of B into DLC leads to the increase of sp{sup 3} bonded carbon in the films, the increase of both film hardness and elastic modulus, and the decrease of both surface roughness and friction coefficient. Furthermore, the content of sp{sup 3} bonded carbon, film hardness and elastic modulus increase, and the film surface roughness and friction coefficient decrease with the increase of B-rich carbide in the B-DLC films. - Highlights: • Biased target ion beam deposition technique is promising to produce high quality DLC based thin films; • Boron exists in different states in B-DLC thin films; • The incorporation of B to DLC with different levels leads to improved film properties; • The fraction of sp{sup 3} bonded C in B-DLC thin films increase with the increase of B-rich carbide content in the films.

  13. Synthesis and characterization of boron incorporated diamond-like carbon thin films

    International Nuclear Information System (INIS)

    Boron incorporated diamond-like carbon (B-DLC) (up to 8 wt.% boron) thin films were synthesized on silicon wafers using biased target ion beam deposition technique, where diamond-like carbon (DLC) was deposited by ion beam deposition and boron (B) was simultaneously incorporated by biased target sputtering of a boron carbide (B4C) target under different conditions. Pure DLC films and B–C films were also synthesized by ion beam deposition and biased target sputtering of B4C under similar conditions, respectively, as reference samples. The microstructure and mechanical properties of the synthesized films have been characterized by various technologies. It has been found that B exists in different states in B-DLC, including carbon-rich and B-rich boron carbides, boron suboxide and boron oxide, and the oxidation of B probably occurs during the film deposition. The incorporation of B into DLC leads to the increase of sp3 bonded carbon in the films, the increase of both film hardness and elastic modulus, and the decrease of both surface roughness and friction coefficient. Furthermore, the content of sp3 bonded carbon, film hardness and elastic modulus increase, and the film surface roughness and friction coefficient decrease with the increase of B-rich carbide in the B-DLC films. - Highlights: • Biased target ion beam deposition technique is promising to produce high quality DLC based thin films; • Boron exists in different states in B-DLC thin films; • The incorporation of B to DLC with different levels leads to improved film properties; • The fraction of sp3 bonded C in B-DLC thin films increase with the increase of B-rich carbide content in the films

  14. Synthesis and evaluation of thymidine kinase 1-targeting carboranyl pyrimidine nucleoside analogs for boron neutron capture therapy of cancer.

    Science.gov (United States)

    Agarwal, Hitesh K; Khalil, Ahmed; Ishita, Keisuke; Yang, Weilian; Nakkula, Robin J; Wu, Lai-Chu; Ali, Tehane; Tiwari, Rohit; Byun, Youngjoo; Barth, Rolf F; Tjarks, Werner

    2015-07-15

    A library of sixteen 2nd generation amino- and amido-substituted carboranyl pyrimidine nucleoside analogs, designed as substrates and inhibitors of thymidine kinase 1 (TK1) for potential use in boron neutron capture therapy (BNCT) of cancer, was synthesized and evaluated in enzyme kinetic-, enzyme inhibition-, metabolomic-, and biodistribution studies. One of these 2nd generation carboranyl pyrimidine nucleoside analogs (YB18A [3]), having an amino group directly attached to a meta-carborane cage tethered via ethylene spacer to the 3-position of thymidine, was approximately 3-4 times superior as a substrate and inhibitor of hTK1 than N5-2OH (2), a 1st generation carboranyl pyrimidine nucleoside analog. Both 2 and 3 appeared to be 5'-monophosphorylated in TK1(+) RG2 cells, both in vitro and in vivo. Biodistribution studies in rats bearing intracerebral RG2 glioma resulted in selective tumor uptake of 3 with an intratumoral concentration that was approximately 4 times higher than that of 2. The obtained results significantly advance the understanding of the binding interactions between TK1 and carboranyl pyrimidine nucleoside analogs and will profoundly impact future design strategies for these agents. PMID:26087030

  15. Involvement of Tspan8 in exosome assembly and target cell selection

    OpenAIRE

    Rana, Sanyukta

    2010-01-01

    Exosomes are the most important intercellular communicators. Tetraspanins/their complexes are suggested to be important in exosomal target cell selection. I showed: changes in Tetraspanin8 associations created from internalization persist upto exosomes and, differences in tetraspanin-complexes on exosomes allow for target cell selectivity.Based on the tetraspanin-complex on exosomes, predictions on potential target cells might be possible, allowing tailored exosome generation for drug delivery.

  16. Understanding the deposition mechanism of pulsed laser deposited B-C films using dual-targets

    International Nuclear Information System (INIS)

    Boron carbide thin films with stoichiometry (boron-carbon atomic ratio) range of 0.1 ∼ 8.9 were fabricated via pulsed laser deposition by using boron-carbon dual-targets. However, this experimental data on stoichiometry were smaller than the computer simulation values. The discrepancy was investigated by studies on composition and microstructure of the thin films and targets by scanning electron microscopy, excitation laser Raman spectroscopy, and X-ray photoelectron spectroscopy. The results indicate that the boron liquid droplets were formed by phase explosion after laser irradiation on boron sector. Part of the boron droplets would be lost via ejection in the direction of laser beam, which is tilted 45° to the surface of substrate

  17. Genome Sequence of Klebsiella pneumoniae Ecl8, a Reference Strain for Targeted Genetic Manipulation

    OpenAIRE

    Fookes, Maria; Yu, Jing; De Majumdar, Shyamasree; Thomson, Nicholas; Schneiders, Thamarai

    2013-01-01

    We report the genome sequence of Klebsiella pneumoniae subsp. pneumoniae Ecl8, a spontaneous streptomycin-resistant mutant of strain ECL4, derived from NCIB 418. K. pneumoniae Ecl8 has been shown to be genetically tractable for targeted gene deletion strategies and so provides a platform for in-depth analyses of this species.

  18. Crystal structure of bis-(3-bromo-mesit-yl)(quino-lin-1-ium-8-yl)boron(III) tribromide.

    Science.gov (United States)

    Son, Jungho; Tamang, Sem Raj; Hoefelmeyer, James D

    2015-09-01

    The title compound, C27H26.82BBr2.18N(+)·Br3 (-), is a cationic tri-aryl-borane isolated as its tribromide salt. The aryl substituents include a protonated 8-quinolyl group and two 3-bromo-mesityl groups. The mol-ecule was prepared on combination of 3:1 Br2 and dimesit-yl(quinolin-8-yl)borane in hexa-nes. The refinement of the structure indicated a degree of 'over-bromination' (beyond two bromine atoms) for the cation. There are two tribromide ions in the asymmetric unit, both completed by crystallographic inversion symmetry. PMID:26396861

  19. Laser-initiated primary and secondary nuclear reactions in Boron-Nitride

    Science.gov (United States)

    Labaune, C.; Baccou, C.; Yahia, V.; Neuville, C.; Rafelski, J.

    2016-02-01

    Nuclear reactions initiated by laser-accelerated particle beams are a promising new approach to many applications, from medical radioisotopes to aneutronic energy production. We present results demonstrating the occurrence of secondary nuclear reactions, initiated by the primary nuclear reaction products, using multicomponent targets composed of either natural boron (B) or natural boron nitride (BN). The primary proton-boron reaction (p + 11B → 3 α + 8.7 MeV), is one of the most attractive aneutronic fusion reaction. We report radioactive decay signatures in targets irradiated at the Elfie laser facility by laser-accelerated particle beams which we interpret as due to secondary reactions induced by alpha (α) particles produced in the primary reactions. Use of a second nanosecond laser beam, adequately synchronized with the short laser pulse to produce a plasma target, further enhanced the reaction rates. High rates and chains of reactions are essential for most applications.

  20. Analysis of the electron density features of small boron clusters and the effects of doping with C, P, Al, Si, and Zn: Magic B7P and B8Si clusters

    Science.gov (United States)

    Saha, P.; Rahane, A. B.; Kumar, V.; Sukumar, N.

    2016-05-01

    Boron atomic clusters show several interesting and unusual size-dependent features due to the small covalent radius, electron deficiency, and higher coordination number of boron as compared to carbon. These include aromaticity and a diverse array of structures such as quasi-planar, ring or tubular shaped, and fullerene-like. In the present work, we have analyzed features of the computed electron density distributions of small boron clusters having up to 11 boron atoms, and investigated the effect of doping with C, P, Al, Si, and Zn atoms on their structural and physical properties, in order to understand the bonding characteristics and discern trends in bonding and stability. We find that in general there are covalent bonds as well as delocalized charge distribution in these clusters. We associate the strong stability of some of these planar/quasiplanar disc-type clusters with the electronic shell closing with effectively twelve delocalized valence electrons using a disc-shaped jellium model. {{{{B}}}9}-, B10, B7P, and B8Si, in particular, are found to be exceptional with very large gaps between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, and these are suggested to be magic clusters.

  1. Determination of boron content in boron carbide, boron nitride and amorphous boron

    International Nuclear Information System (INIS)

    In the present article an analyzing method of determination of boron content in boron carbide, boron nitride and amorphous boron described. Examined samples were digested with potassium hydroxide and potassium nitrate in nickel crucible and the boron contents determined subsequently by an alcalimetric titration of boric acid in presence of mannite resp. sorbite. (author)

  2. Analysis of magnetron sputtered boron oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Buc, Dalibor [Slovak University of Technology in Bratislava (Slovakia); Bello, Igor [City University of Hong Kong, Kowloon, Hong Kong (China); Caplovicova, Maria [Comenius University in Bratislava (Slovakia); Mikula, Milan; Kovac, Jaroslav; Hotovy, Ivan [Slovak University of Technology in Bratislava (Slovakia); Chong, Yat Min [City University of Hong Kong, Kowloon, Hong Kong (China); Siu, Guei Gu [City University of Hong Kong, Kowloon, Hong Kong (China)], E-mail: apggsiu@cityu.edu.hk

    2007-10-15

    Boron oxide films were grown on silicon substrates by radio-frequency (rf) unbalanced magnetron sputtering of a boron target in argon-oxygen gas mixtures with different compositions. Microscopic analyses show that overall boron oxide films are amorphous. The film prepared at oxygen/argon flow rate ratio > 0.05 developed large crystallites of boric acid in localize areas of amorphous boron oxide matrices. These crystallites were unstable and at electron microscopic analysis they continuously transformed to a cubic HBO{sub 2} phase and then completely vanished leaving an underlying amorphous boron oxide film behind. The analyses indicate the coexistence of B{sub 6}O, HBO{sub 2} crystallites and amorphous boron oxide matrices. Fourier transform infrared (FTIR) spectra revealed spectral bands of BOH, BO, BOB and BH groups. Nanohardness and elastic modulus of a film prepared at low oxygen concentration approach 30 and 300 GPa, respectively. These parameters however vary with deposition conditions.

  3. Banishing brittle bones with boron

    Energy Technology Data Exchange (ETDEWEB)

    A 6-month study indicates that boron, not even considered an essential nutrient for people and animals, may be a key to preventing osteoporosis, say nutritionist Forrest H. Nielsen and anatomist Curtiss D. Hunt at ARS' Grand Forks, North Dakota, Human Nutrition Research Center. They believe the results of the study - the first to look at the nutritional effects of boron in humans - will generate a lot of interest in the element. In the study, 12 postmenopausal women consumed a very low boron diet (0.25 milligrams per day) for 17 weeks then were given a daily 3-mg supplement - representing the boron intake from a well-balanced diet - for 7 more weeks. Within 8 days after the supplement was introduced, the lost 40 percent less calcium, one-third less magnesium, and slightly less phosphorus through the urine. In fact, their calcium and magnesium losses were lower than prestudy levels, when they were on their normal diets. Since boron isn't considered essential for people, there is not recommended intake and no boron supplement on the market. Nielsen says the supplement of sodium borate used in the study was specially prepared based on the amount of boron a person would get from a well-balanced diet containing fruits and vegetables. He says the average boron intake is about 1.5 mg - or half the experimental dose - but average means a lot of people get less and a lot get more. Hunt cautioned that large doses of boron can be toxic, even lethal. The lowest reported lethal dose of boric acid is about 45 grams (1.6 ounces) for an adult and only 2 grams (0.07 ounce) for an infant.

  4. Optical Calibration Of The Sudbury Neutrino Observatory And Determination Of The Boron-8 Solar Neutrino Flux In The Salt Phase

    CERN Document Server

    Grant, D R

    2004-01-01

    An improved measurement of the 8B solar neutrino flux has been made at the Sudbury Neutrino Observatory (SNO). This measurement has an increased sensitivity to the neutral current reaction. This is due to an enhanced neutron capture efficiency, accomplished by adding salt, NaCl, to the heavy water in the detector. The data set analyzed in the salt phase consists of approximately 254 days of neutrino data. The data set has been analyzed using independently developed probability density functions (PDFs) in an extended maximum likelihood calculation. The final 8B model-constrained results of this analysis are given by the fluxes (in units of 106 neutrinos/(cm2s)): •FSunCC=1 .69±0.07stat +0.07- 0.08 syst •FSunNC=4.91±0.2 3stat +0.32-0.27 syst •FSumES=2.11 +0.29- 0.27 stat+0.13 -0.19syst These fluxes give a CC/NC ratio of 0.344 ± 0.021(stat) +0.07- 0.08 syst . The results clearly demonstrate that solar neutrinos are oscillating from one flavor to a...

  5. CXCL8 as a Potential Therapeutic Target for HIV-Associated Neurocognitive Disorders.

    Science.gov (United States)

    Mamik, Manmeet K; Ghorpade, Anuja

    2016-01-01

    Chemokine CXCL8 is a low molecular weight neutrophil chemoattractant implicated in various neurodegenerative disorders including Alzheimer's disease and stroke. Increased expression of CXCL8 has been reported in serum, plasma and brain of human immunodeficiency virus (HIV)-1 infected individuals with neurocognitive impairment, indicating its role in neuroinflammation associated with HIV-1 infection of the brain. Since chemokines are critical in eliciting immune responses in the central nervous system (CNS), CXCL8 is of particular importance for being one of the first chemokines described in the brain. Activation of astrocytes and microglia by HIV-1 and virus associated proteins results in production of this chemokine in the brain microenvironment. Consequently, CXCL8 exerts its effect on target cells via Gprotein coupled receptors CXCR1 and CXCR2. Neutrophils are the main target cells for CXCL8; however, microglia and neurons also express CXCR1/CXCR2 and therefore are important targets for CXCL8-mediated crosstalk. The objective of this review is to focus on CXCL8 production, signaling and regulation in neuronal and glial cells in response to HIV-1 infection. We highlight the role of HIV-1 secreted proteins such as trans-activator of transcription, envelope glycoprotein, negative regulatory factor and viral protein r in the regulation of CXCL8. We discuss dual role of CXCL8 in neurodegeneration as well as neuroprotection in the CNS. Thus, targeting CXCL8 through the development of CXCR1/CXCR2-based therapeutic strategies to either selectively agonize or antagonize receptors may be able to selectively promote neuroprotective and anti-inflammatory outcomes, leading to significant clinical applications in many neuroinflammatory CNS diseases, including HIV-associated neurocognitive disorders. PMID:26112047

  6. Proliferating cell nuclear antigen (Pcna) as a direct downstream target gene of Hoxc8

    Energy Technology Data Exchange (ETDEWEB)

    Min, Hyehyun; Lee, Ji-Yeon; Bok, Jinwoong; Chung, Hyun Joo [Department of Anatomy, Embryology Laboratory, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Kim, Myoung Hee, E-mail: mhkim1@yuhs.ac [Department of Anatomy, Embryology Laboratory, Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of)

    2010-02-19

    Hoxc8 is a member of Hox family transcription factors that play crucial roles in spatiotemporal body patterning during embryogenesis. Hox proteins contain a conserved 61 amino acid homeodomain, which is responsible for recognition and binding of the proteins onto Hox-specific DNA binding motifs and regulates expression of their target genes. Previously, using proteome analysis, we identified Proliferating cell nuclear antigen (Pcna) as one of the putative target genes of Hoxc8. Here, we asked whether Hoxc8 regulates Pcna expression by directly binding to the regulatory sequence of Pcna. In mouse embryos at embryonic day 11.5, the expression pattern of Pcna was similar to that of Hoxc8 along the anteroposterior body axis. Moreover, Pcna transcript levels as well as cell proliferation rate were increased by overexpression of Hoxc8 in C3H10T1/2 mouse embryonic fibroblast cells. Characterization of 2.3 kb genomic sequence upstream of Pcna coding region revealed that the upstream sequence contains several Hox core binding sequences and one Hox-Pbx binding sequence. Direct binding of Hoxc8 proteins to the Pcna regulatory sequence was verified by chromatin immunoprecipitation assay. Taken together, our data suggest that Pcna is a direct downstream target of Hoxc8.

  7. Efficient boron-carbon-nitrogen nanotube formation via combined laser-gas flow levitation

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, R Roy; Jordan, Kevin; Smith, Michael W

    2015-03-24

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  8. Efficient boron nitride nanotube formation via combined laser-gas flow levitation

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, R. Roy; Jordan, Kevin; Smith, Michael

    2014-03-18

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  9. Efficient Boron-Carbon-Nitrogen Nanotube Formation Via Combined Laser-Gas Flow Levitation

    Science.gov (United States)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2015-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz.

  10. Efficient Boron Nitride Nanotube Formation via Combined Laser-Gas Flow Levitation

    Science.gov (United States)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2014-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z) The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z).

  11. Boron removal from geothermal waters by electrocoagulation

    International Nuclear Information System (INIS)

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm2, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%

  12. Boron removal from geothermal waters by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey); Yilmaz, M. Tolga; Paluluoglu, Cihan [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)

    2008-05-01

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm{sup 2}, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.

  13. Identification of conserved, centrosome-targeting ASH domains in TRAPPII complex subunits and TRAPPC8

    DEFF Research Database (Denmark)

    Schou, Kenneth Bødtker; Morthorst, Stine Kjær; Christensen, Søren Tvorup;

    2014-01-01

    BACKGROUND: Assembly of primary cilia relies on vesicular trafficking towards the cilium base and intraflagellar transport (IFT) between the base and distal tip of the cilium. Recent studies have identified several key regulators of these processes, including Rab GTPases such as Rab8 and Rab11, the...... exact molecular mechanisms by which these proteins interact and target to the basal body to promote ciliogenesis are not fully understood. RESULTS: We surveyed the human proteome for novel ASPM, SPD-2, Hydin (ASH) domain-containing proteins. We identified the TRAPP complex subunits TRAPPC8, -9, -10, -11...... domains confer targeting to the centrosome and cilia, and that TRAPPC8 has cilia-related functions. Further, we propose that the yeast TRAPPII complex and its mammalian counterpart are evolutionarily related to the bacterial periplasmic trafficking chaperone PapD of the usher pili assembly machinery....

  14. Technology of boron-containing polyphosphate fertilizer 'Phosphobor'

    International Nuclear Information System (INIS)

    A technology is developed for producing 'Phosphobor' fertilizer based on the rock phosphate weal (17-18% P2O5) with additions of boron-magnesium compound. Boron is part of polyphosphate fertilizer in the form of polymeric compounds of phosphorus and boron. Phosphorus and boron copolymers -boratophosphates - are easily formed in the process of polyphosphate fertilizers production, since borates undergo a mutual polycondensation reaction with phosphates. 8 refs., 1 fig

  15. Elementary boron and metal-boron compounds

    International Nuclear Information System (INIS)

    Elementary boron is of interest for its peculiar and difficult bonding behaviour in solids. Due to its high oxygen affinity we find no elementary boron in nature. For the same reason it is difficult to isolate pure, elementary boron, and much confusion about 'boron crystals' has been the result of more than 100 years of research. The polymorphic forms of elementary boron and its closely related higher carbides and higher metal borides as well as the simple metal borides, B3C and BN are reported. The quantum-mechanical background responsible for structure and stoichiometry of these crystals is given. (orig.)

  16. Mouse Homologue of the Schizophrenia Susceptibility Gene ZNF804A as a Target of Hoxc8

    Directory of Open Access Journals (Sweden)

    Hyun Joo Chung

    2010-01-01

    Full Text Available Using a ChIP-cloning technique, we identified a Zinc finger protein 804a (Zfp804a as one of the putative Hoxc8 downstream target genes. We confirmed binding of Hoxc8 to an intronic region of Zfp804a by ChIP-PCR in F9 cells as well as in mouse embryos. Hoxc8 upregulated Zfp804a mRNA levels and augmented minimal promoter activity in vitro. In E11.5 mouse embryos, Zfp804a and Hoxc8 were coexpressed. Recent genome-wide studies identified Zfp804a (or ZNF804A in humans as a plausible marker for schizophrenia, leading us to hypothesize that this embryogenic regulatory control might also exert influence in development of complex traits such as psychosis.

  17. Target studies for the production of lithium8 for neutrino physics using a low energy cyclotron

    OpenAIRE

    Bungau, Adriana; Barlow, Roger; Shaevitz, Michael; Conrad, Janet; Spitz, Joshua

    2012-01-01

    Lithium 8 is a short lived beta emitter producing a high energy anti-neutrino, which is very suitable for making several measurements of fundamental quantities. It is proposed to produce Lithium 8 with a commercially available 60 MeV cyclotron using protons or alpha particles on a Beryllium 9 target. We have used the GEANT4 program to model these processes, and calculate the anti-neutrino fluxes that could be obtained in a practical system. We also calculate the production of undesirable cont...

  18. The influence of Boron on creep-rupture behaviour of austenitic unstabilized and Nb-stabilized stainless steel X8CrNi 1613 in unirradiated and irradiated condition

    International Nuclear Information System (INIS)

    The present study deals with influence of boron on creep-rupture behaviour in unirradiated condition at 6500C along with precipitation behaviour, heat-treatment and recrystallization of unstabilized and stabilized steel. The results of creep-rupture tests on unirradiated specimens show that boron exerts a beneficial effect on the rupture life and ductility. Boron losses its beneficial effect on creep properties in unstabilized steel by prolong creeping. The magnitude of beneficial effect of Boron on creep properties depends upon the initial boron distribution which influences the number, size and distribution of the precipitates. Boron promotes the precipitation of type M23C6 Carbides in the grain as well as at the grain boundary. Boron segregates in atomic form during slow cooling from austenitizing temperature. The recrystallization will be delayed by the presence of boron. The results of creep tests at 6500C shows that boron exerts a beneficial effect on creep life of irradiated steels. (orig./GSC)

  19. Proceedings of workshop on 'boron science and boron neutron capture therapy'

    Energy Technology Data Exchange (ETDEWEB)

    Kitaoka, Y. [ed.

    1998-12-01

    This volume contains the abstracts and programs of the 8th (1996), 9th (1997) and 10th (1998) of the workshop on 'the Boron Science and Boron Neutron Capture Therapy' and the recent progress reports especially subscribed. The 11 of the presented papers are indexed individually. (J.P.N.)

  20. Simultaneous determination of boron-10 and boron-11 under proton bombardment

    International Nuclear Information System (INIS)

    The isotopic analysis of boron gained importance with increased use of boron-10 in nuclear technology. Former techniques for determining the stable boron isotope either were limited to the determination of a single isotope or required tedious experimental prodecure. The use of proton induced reactions was therefore investigated as an alternative method for the simultaneous analysis of both stable isotopes of boron through a relatively simple experimental procedure. Aqueous solutions of natural boric acid (19,78 at. % 10B) and enriched boric acid (92,41 at. % 10B) were mixed and evaporated to dryness in order to obtain samples in which the isotopic concentration of boron was known. Thin targets were produced by evaporating boron oxide, converted by heat from the boric acid mixture, onto tantalum backing material. Standard samples with known contents of boron oxide were prepared by dry mixing standard reference boron-containing glass powers in a ball mill. Thick targets containing boron of different isotopic compositions were prepared in matrices of potassium bromide and of ion-exchange resins by mixing the matrix with aqueous solutions of boric acid and of sodium carbonate by fusion with boric oxide. The most intense prompt gamma-rays emitted from boron isotopes under irradiation with protons up to 4,5 MeV were the 428-KeV 10B α(1,0), 718-KeV 10B p(1,0) and the 2124-KeV 11B p(1,0) gamma-rays. Excitation functions for the production of each of these were measured using both thick and thin targets

  1. Synthesis and evaluation of boron folates for Boron-Neutron-Capture-Therapy (BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Kettenbach, Kathrin; Schieferstein, Hanno; Grunewald, Catrin; Hampel, Gabriele; Schuetz, Christian L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Iffland, Dorothee; Bings, Nicolas H. [Mainz Univ. (Germany). Inst. of Inorganic Chemistry and Analytical Chemistry; Reffert, Laura M. [Hannover Medical School (Germany). Radiopharmaceutical Chemistry; Ross, Tobias L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Hannover Medical School (Germany). Radiopharmaceutical Chemistry

    2015-07-01

    Boron neutron capture therapy (BNCT) employs {sup 10}B-pharmaceuticals administered for the treatment of malignancies, and subsequently irradiated with thermal neutrons. So far, clinical established pharmaceuticals like boron phenylalanine (BPA) or sodium boron mercaptate (BSH) use imperfect (BPA) or passive (BSH) targeting for accumulation at target sites. Due to the need of a selective transportation of boron drugs into cancer cells and sparing healthy tissues, we combined the BNCT approach with the specific and effective folate receptor (FR) targeting concept. The FR is overexpressed on many human carcinomas and provides a selective and specific target for molecular imaging as well as for tumor therapy. We synthesized and characterized a carborane-folate as well as a BSH-folate to study their in vitro characteristics and their potential as new boron-carriers for BNCT. Uptake studies were carried out using human KB cells showing a significant increase of the boron content in cells and demonstrating the successful combination of active FR-targeting and BNCT.

  2. Screening of the target genes trans-activated by HLA-HA8 in hepatocytes

    Directory of Open Access Journals (Sweden)

    Qi WANG

    2011-06-01

    Full Text Available Objective To clone and identify the target genes trans-activated by human minor histocompatibility antigen HLA-HA8 in hepatocytes with suppression subtractive hybridization(SSH and bioinfomatics technique.Methods mRNA was isolated from HepG2 cells transfected by pcDNA3.1(--HLA-HA8 and pcDNA3.1(- empty vector,and then used to synthesize the double-stranded cDNA(marked as Tester and Driver,respectively by reverse transcription.After being digested with restriction enzyme Rsa I,the tester cDNA was divided into two parts and ligated to the specific adaptor 1 and adaptor 2,respectively,and then hybridized with driver cDNA twice and underwent PCR twice.The production was subcloned into pEGM-Teasy plasmid vectors to set up the subtractive library.The library was then amplified by transfection into E.coli strain DH5α.The cDNA was sequenced and analyzed in GenBank with Blast search after PCR amplification.Results The subtractive library of genes trans-activated by HLA-HA8 was constructed successfully.The amplified library contained 101 positive clones.Colony PCR showed that all these clones contained 200-1000bp inserts.Twenty eight clones were selected randomly to analyze the sequences.The result of homologous analysis showed that altogether 16 coding sequences were gotten,of which 4 sequences were with unknown function.Conclusions The obtained sequences trans-activated by HLA-HA8 may code different proteins and play important roles in cell growth and metabolism,energy synthesis and metabolism,material transport and signal transduction.This finding will bring some new clues for the studies not only on the biological functions of HLA-HA8,but also on the HBV infection mechanism.

  3. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Mass spectrometric determination of boron isotope in boron carbide

    International Nuclear Information System (INIS)

    Boron isotopes in boron carbide are measured by thermionic ionization mass spectrometry with no prior chemical separation. Boron is converted to sodium borate by fusion of the boron carbide with sodium hydroxide (or sodium carbonate) directly on the rhenium filament. The boron isotopic ratios are measured by using the Na2BO2+ ion

  5. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey)

    2007-10-22

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively.

  6. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    International Nuclear Information System (INIS)

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively

  7. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors. PMID:24387907

  8. Boron carbide whisker and platelet reinforced ceramic matrix composites

    International Nuclear Information System (INIS)

    Boron carbide whisker and platelet-reinforced alumina and boron-carbide-whisker-reinforced silicon carbide composites were prepared by hot-pressing. The mechanical properties of hot-pressed boron carbide platelet and whisker-reinforced composites are better than the inherent ceramic matrix. A maximum fracture toughness, K(lc), of 9.5 MPa sq rt m is achieved for alumina/boron carbide whisker composites, 8.6 MPa sq rt m is achieved for alumina/boron carbide platelet composites, and 3.8 MPa sq rt m is achieved for silicon carbide/boron carbide whisker composites. The fracture toughness is dependent on the volume fraction of the platelets and whiskers. 12 refs

  9. Killing of targets by effector CD8 T cells in the mouse spleen follows the law of mass action

    Energy Technology Data Exchange (ETDEWEB)

    Ganusov, Vitaly V [Los Alamos National Laboratory

    2009-01-01

    In contrast with antibody-based vaccines, it has been difficult to measure the efficacy of T cell-based vaccines and to correlate the efficacy of CD8 T cell responses with protection again viral infections. In part, this difficulty is due to poor understanding of the in vivo efficacy of CD8 T cells produced by vaccination. Using a: recently developed experimental method of in vivo cytotoxicity we have investigated quantitative aspects of killing of peptide-pulsed targets by effector and memory CD8 T cells, specific to three epitopes of lymphocytic choriomeningitis virus (LCMV), in the mouse spleen. By analyzing data on killing of targets with varying number of epitope-specific effector and memory CD8 T cells, we find that killing of targets by effectors follows the law of mass-action, that is the death rate of peptide-pulsed targets is proportional to the frequency of CTLs in the spleen. In contrast, killing of targets by memory CD8 T cells does not follow the mass action law because the death rate of targets saturates at high frequencies of memory CD8 T cells. For both effector and memory cells, we also find little support for the killing term that includes the decrease of the death rate of targets with target cell density. Interestingly, our analysis suggests that at low CD8 T cell frequencies, memory CD8 T cells on the per capita basis are more efficient at killing peptide-pulsed targets than effectors, but at high frequencies, effectors are more efficient killers than memory T cells. Comparison of the estimated killing efficacy of effector T cells with the value that is predicted from theoretical physics and based on motility of T cells in lymphoid tissues, suggests that limiting step in the killing of peptide-pulsed targets is delivering the lethal hit and not finding the target. Our results thus form a basis for quantitative understanding of the process of killing of virus-infected cells by T cell responses in tissues and can be used to correlate the

  10. Friction anisotropy in boronated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N., E-mail: niranjan@igcar.gov.in [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Radhika, R. [Crystal Growth Centre, Anna University, Chennai (India); Kozakov, A.T. [Research Institute of Physics, Southern Federal University, Rostov-on-Don (Russian Federation); Pandian, R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Chakravarty, S. [UGC-DAE CSR, Kalpakkam (India); Ravindran, T.R.; Dash, S.; Tyagi, A.K. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2015-01-01

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient.

  11. Friction anisotropy in boronated graphite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient

  12. Inheritance of Boron Efficiency in Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    SHI Lei; WANG Yun-Hua; NIAN Fu-Zhao; LU Jian-Wei; MENG Jin-Ling; XU Fang-Sen

    2009-01-01

    Field experiments were conducted to study the inheritance of boron efficiency in oilseed rape (Brassica napus L.) by evaluating the boron (B) efficiency coefficient (BEC,the ratio of the seed yield at below the critical boron level to that at the boron-sufficient level) with 657 F2:3 fines of a population derived from a cross between a B-efficient cultivar,Qingyou 10,and a B-inefficient cultivar,Bakow.Qingyou i0 had high BEC as well as high seed yield at low available soil B.On the contrary,Bakow produced low seed yield at low B status.Boron deficiency decreased the seed yield of the F2:3 lines to different extents and the distribution of BEC of the population showed a bimodal pattern.When the 657 F2:3 lines were grouped into B-efficient lines and B-inefficient lines according to their BEC,the ratio of B-efficient lines to B-inefficient lines fitted the expected ratio (3:1),indicating that one major gene controlled the B-efficiency trait.127 F2:3 lines selected from the population at random,with distribution of BEC similar to that of the overall population,were used to identify the target region for fine mapping of the boron efficiency gene.

  13. Boron removal from aqueous solution by direct contact membrane distillation

    International Nuclear Information System (INIS)

    The removal of boron from aqueous solution by direct contact membrane distillation (DCMD) was studied with self-prepared polyvinylidene fluoride (PVDF) hollow fiber membranes in the present work. The effect of pH, boron concentration, temperature and salt concentration of the feed solution on the boron rejection was investigated. The experimental results indicated that boron rejection was less dependent on the feed pH and salt concentration. DCMD process had high boron removal efficiency (>99.8%) and the permeate boron was below the maximum permissible level even at feed concentration as high as 750 mg/L. Although the permeate flux was enhanced exponentially with the feed temperature increasing, the influence of feed temperature on the boron rejection could be neglected. Finally, the natural groundwater sample containing 12.7 mg/L of boron was treated by DCMD process. The permeate boron kept below 20 μg/L whether the feed was acidified or not, but pre-acidification was helpful to maintain the permeate flux stability. All the experimental results indicated that DCMD could be efficiently used for boron removal from aqueous solution.

  14. Measurement of the $^{7}$Be$(p,\\gamma)^{8}$B Cross-Section with an Implanted Target

    CERN Multimedia

    2002-01-01

    % IS366\\\\ \\\\ The $^7$Be(p,$\\gamma)^8$B capture reaction is of major importance to the physics of the sun and the issues of the ``solar neutrino puzzle'' and neutrino masses. We report here on a new determination of the absolute cross section of this reaction, using a novel method which overcomes some of the major experimental uncertainties of previous measurements. We utilize an implanted $^7$Be target and a uniformly scanned particle beam larger than the target spot, eliminating issues of target homogeneity and backscattering loss of $^8$B reaction products. The target was produced using a beam of 1.8 10$^{10}$/s $^7$Be nuclei extracted at ISOLDE(CERN) from a graphite target bombarded by 1 GeV protons in a two-step resonant laser ionization source. The $^7$Be nuclei were directly implanted into a copper substrate to obtain a target of 2 mm diameter with a total of 3.10$^{15}$ atoms. The measurement of the $^8$B production cross section was carried out at the Van de Graaff laboratory of the Weizmann Institute...

  15. Structure and single-phase regime of boron carbides

    Science.gov (United States)

    Emin, David

    1988-09-01

    The boron carbides are composed of twelve-atom icosahedral clusters which are linked by direct covalent bonds and through three-atom intericosahedral chains. The boron carbides are known to exist as a single phase with carbon concentrations from about 8 to about 20 at. %. This range of carbon concentrations is made possible by the substitution of boron and carbon atoms for one another within both the icosahedra and intericosahedral chains. The most widely accepted structural model for B4C (the boron carbide with nominally 20% carbon) has B11C icosahedra with C-B-C intericosahedral chains. Here, the free energy of the boron carbides is studied as a function of carbon concentration by considering the effects of replacing carbon atoms within B4C with boron atoms. It is concluded that entropic and energetic considerations both favor the replacement of carbon atoms with boron atoms within the intericosahedral chains, C-B-C-->C-B-B. Once the carbon concentration is so low that the vast majority of the chains are C-B-B chains, near B13C2, subsequent substitutions of carbon atoms with boron atoms occur within the icosahedra, B11C-->B12. Maxima of the free energy occur at the most ordered compositions: B4C,B13C2,B14C. This structural model, determined by studying the free energy, agrees with that previously suggested by analysis of electronic and thermal transport data. These considerations also provide an explanation for the wide single-phase regime found for boron carbides. The significant entropies associated with compositional disorder within the boron carbides, the high temperatures at which boron carbides are formed (>2000 K), and the relatively modest energies associated with replacing carbon atoms with boron atoms enable the material's entropy to be usually important in determining its composition. As a result, boron carbides are able to exist in a wide range of compositions.

  16. Targeting of a CCK{sub 2} receptor splice variant with {sup 111}In-labelled cholecystokinin-8 (CCK8) and {sup 111}In-labelled minigastrin

    Energy Technology Data Exchange (ETDEWEB)

    Laverman, Peter; Gotthardt, Martin; Oyen, Wim J.G.; Boerman, Otto C. [Radboud University Nijmegen Medical Center, Department of Nuclear Medicine, PO Box 9101, HB Nijmegen (Netherlands); Roosenburg, Susan [Radboud University Nijmegen Medical Center, Department of Nuclear Medicine, PO Box 9101, HB Nijmegen (Netherlands); Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen (Netherlands); Park, Jeseong; Hellmich, Mark R. [University of Texas Medical Branch, Department of Surgery and the Sealy Center for Cancer Cell Biology, Galveston, TX (United States); Jong, Marion de [Erasmus Medical Center, Department of Nuclear Medicine, Rotterdam (Netherlands); Rutjes, Floris P.J.T.; Delft, Floris L. van [Radboud University Nijmegen, Institute for Molecules and Materials, Nijmegen (Netherlands)

    2008-02-15

    Radiolabelled cholecystokinin (CCK) and gastrin-derived peptides potentially can be used for peptide receptor radionuclide therapy (PRRT). Recently, a splice variant version of the CCK2R has been identified, designated CCK2i4svR. Constitutive expression of this receptor has been demonstrated in human colorectal cancer and in pancreatic cancer, but not in normal tissue. So far, it has never been shown whether radiolabelled peptides can target the CCK2i4svR in vivo. In this paper, we investigated the potential of sulfated {sup 111}In-labelled DOTA-CCK8 (sCCK8), a pan-CCKR-binding peptide, and [{sup 111}In]DOTA-minigastrin (MG0), a CCK2R selective peptide, for the targeting of the CCK2i4svR. The receptor binding affinity of [{sup 111}In]DOTA-sCCK8 and [{sup 111}In]DOTA-MG0 for the CCK2R and CCK2i4svR was determined using stably transfected HEK293 cell lines, expressing either CCK2R or CCK2i4svR. Tumour targeting was studied in HEK293-CCK2i4svR tumour-bearing athymic mice. [{sup 111}In]DOTA-sCCK8 as well as [{sup 111}In]DOTA-MG0 specifically bound both CCK2R and CCK2i4svR with affinities in the low nanomolar range. In vivo experiments revealed that accumulation of both peptides in CCK2i4svR-positive tumours was similar (3.21 {+-} 0.77 and 3.01 {+-} 0.67%ID/g, sCCK8 and MG0, respectively, 24 h p.i.). Kidney retention of [{sup 111}In]DOTA-MG0 (32.4 {+-} 7.5%ID/g, 24 h p.i.) was markedly higher than that of [{sup 111}In]DOTA-sCCK8 (2.75 {+-} 0.31%ID/g, 24 h p.i.). We demonstrated that the CCK2i4svR is a potential target for PRRT using a radiolabelled sulfated CCK8 peptide. As this receptor is expressed on colorectal and pancreatic tumours, but not in normal tissue, these tumours are potentially new targets for PRRT with CCK8 and gastrin analogs. (orig.)

  17. Targeting of a CCK2 receptor splice variant with 111In-labelled cholecystokinin-8 (CCK8) and 111In-labelled minigastrin

    International Nuclear Information System (INIS)

    Radiolabelled cholecystokinin (CCK) and gastrin-derived peptides potentially can be used for peptide receptor radionuclide therapy (PRRT). Recently, a splice variant version of the CCK2R has been identified, designated CCK2i4svR. Constitutive expression of this receptor has been demonstrated in human colorectal cancer and in pancreatic cancer, but not in normal tissue. So far, it has never been shown whether radiolabelled peptides can target the CCK2i4svR in vivo. In this paper, we investigated the potential of sulfated 111In-labelled DOTA-CCK8 (sCCK8), a pan-CCKR-binding peptide, and [111In]DOTA-minigastrin (MG0), a CCK2R selective peptide, for the targeting of the CCK2i4svR. The receptor binding affinity of [111In]DOTA-sCCK8 and [111In]DOTA-MG0 for the CCK2R and CCK2i4svR was determined using stably transfected HEK293 cell lines, expressing either CCK2R or CCK2i4svR. Tumour targeting was studied in HEK293-CCK2i4svR tumour-bearing athymic mice. [111In]DOTA-sCCK8 as well as [111In]DOTA-MG0 specifically bound both CCK2R and CCK2i4svR with affinities in the low nanomolar range. In vivo experiments revealed that accumulation of both peptides in CCK2i4svR-positive tumours was similar (3.21 ± 0.77 and 3.01 ± 0.67%ID/g, sCCK8 and MG0, respectively, 24 h p.i.). Kidney retention of [111In]DOTA-MG0 (32.4 ± 7.5%ID/g, 24 h p.i.) was markedly higher than that of [111In]DOTA-sCCK8 (2.75 ± 0.31%ID/g, 24 h p.i.). We demonstrated that the CCK2i4svR is a potential target for PRRT using a radiolabelled sulfated CCK8 peptide. As this receptor is expressed on colorectal and pancreatic tumours, but not in normal tissue, these tumours are potentially new targets for PRRT with CCK8 and gastrin analogs. (orig.)

  18. CVD-produced boron filaments

    Science.gov (United States)

    Wawner, F. E.; Debolt, H. E.; Suplinskas, R. D.

    1980-01-01

    A technique for producing boron filaments with an average tensile strength of 6.89 GPa has been developed which involves longitudinal splitting of the filament and core (substrate) removal by etching. Splitting is accomplished by a pinch wheel device which continuously splits filaments in lengths of 3.0 m by applying a force to the side of the filament to create a crack which is then propagated along the axis by a gentle sliding action. To facilitate the splitting, a single 10 mil tungsten substrate is used instead of the usual 0.5 mil substrate. A solution of hot 30% hydrogen peroxide is used to remove the core without attacking the boron. An alternative technique is to alter the residual stress by heavily etching the filament. Average strengths in the 4.83-5.52 GPa range have been obtained by etching an 8 mil filament to 4 mil.

  19. Phase 1 study of monoclonal antibody I-131 3F8 targeted radiation therapy of human neuroblastoma

    International Nuclear Information System (INIS)

    This study is phase I of monoclonal antibody 131-I 3F8 targeted radiotherapy of human neuroblastoma. A murine IgG3 monoclonal antibody specific for ganglioside GD2(3F8), has unusually high (0.08% ID/g) tumor localization in patients and restricted distribution in normal tissues. Nine patients with refractory neuroblastoma (seven with soft tissue masses, four with bone disease, and three with bone marrow disease) have been treated with intravenous I-131 3F8 (10 μg 3F8) and oral saturated solution of potassium iodide and potassium perchlorate. Results are presented

  20. Determination of boron and silicon in boron carbide

    International Nuclear Information System (INIS)

    A sodium carbonate fusion technique for the dissolution of boron carbide followed by the determination of boron by alkalimetric titration and silicon impurity by spectrophotometry is described. The elemental boron content in the commercially available boron carbide ranged from 77.2 to 77.60 % and the silicon in the range 1170 to 2500 ppm. (author)

  1. Proceedings of workshop on 'boron chemistry and boron neutron capture therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the 4th Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 24 in 1992. First, clinical experiences of BNCT in the Kyoto University Research Reactor in 1992 were briefly reported. Then, the killing effects of boron cluster-containing nucleic acid precursors on tumor cells were shown (Chap. 2). The various trials of the optical resolution of B-p-boronophenylalanine for neutron capture therapy were made (Chap. 3). The borate-dextran gel complexes were investigated by the nuclear magnetic resonance spectroscopy. The stability constants of borate complexes were listed, and are useful in the solution chemistry of boron compounds (Chap. 4). The interactions between boron compounds and biological materials were studied by the paper electrophoresis which had been developed by us (Chap. 5). Molecular design of boron-10 carriers and their organic synthesis were reported (Chap. 6). Carborane-containing aziridine boron carriers which were directed to the DNA alkylation were synthesized and their cancer cell killing efficacies were tested (Chap. 7). The solution chemistry of deuterium oxide which is a good neutron moderator was reported, relating to the BNCT (Chap. 8). (author)

  2. Development of beryllium-based neutron target system with three-layer structure for accelerator-based neutron source for boron neutron capture therapy.

    Science.gov (United States)

    Kumada, Hiroaki; Kurihara, Toshikazu; Yoshioka, Masakazu; Kobayashi, Hitoshi; Matsumoto, Hiroshi; Sugano, Tomei; Sakurai, Hideyuki; Sakae, Takeji; Matsumura, Akira

    2015-12-01

    The iBNCT project team with University of Tsukuba is developing an accelerator-based neutron source. Regarding neutron target material, our project has applied beryllium. To deal with large heat load and blistering of the target system, we developed a three-layer structure for the target system that includes a blistering mitigation material between the beryllium used as the neutron generator and the copper heat sink. The three materials were bonded through diffusion bonding using a hot isostatic pressing method. Based on several verifications, our project chose palladium as the intermediate layer. A prototype of the neutron target system was produced. We will verify that sufficient neutrons for BNCT treatment are generated by the device in the near future. PMID:26260448

  3. MicroRNA-218 inhibits the proliferation of human choriocarcinoma JEG-3 cell line by targeting Fbxw8

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Dazun; Tan, Zhihui; Lu, Rong; Yang, Wenqing; Zhang, Yi, E-mail: zhangyi5588@hotmail.com

    2014-08-08

    Highlights: • The miR-218 expression was decreased in choriocarcinoma cell lines. • The Fbxw8 protein expression was increased in choriocarcinoma cell lines. • We show that Fbxw8 is bona-fide target of miR-218 in JEG-3. • Ectopic miR-218 expression inhibits the proliferation of JEG-3 via Fbxw8. • Overexpression of miR-218 affected cyclin A and p27 expression via Fbxw8. - Abstract: MicroRNAs (miRNAs) are endogenous 19–25 nucleotide noncoding single-stranded RNAs that regulate gene expression by blocking the translation or decreasing the stability of mRNAs. In this study, we showed that miR-218 expression levels were decreased while Fbxw8 expression levels were increased in human choriocarcinoma cell lines, and identified Fbxw8 as a novel direct target of miR-218. Overexpression of miR-218 inhibited cell growth arrest at G2/M phase, suppressed the protein levels of cyclin A and up-regulated the expression levels of p27 through decreasing the levels of Fbxw8. On the other hand, forced expression of Fbxw8 partly rescued the effect of miR-218 in the cells, attenuated cell proliferation decrease the percentage of cells at G2/M phase, induced cyclin A protein expression and suppressed the protein level of p27 through up-regulating the levels of Fbxw8. Taken together, these findings will shed light the role to mechanism of miR-218 in regulating JEG-3 cells proliferation via miR-218/Fbxw8 axis, and miR-218 may serve as a novel potential therapeutic target in human choriocarcinoma in the future.

  4. Boron delivery with liposomes for boron neutron capture therapy (BNCT): biodistribution studies in an experimental model of oral cancer demonstrating therapeutic potential

    Energy Technology Data Exchange (ETDEWEB)

    David W. Nigg

    2012-05-01

    Boron neutron capture therapy (BNCT) combines selective accumulation of 10B carriers in tumor tissue with subsequent neutron irradiation. We previously demonstrated the therapeutic efficacy of BNCT in the hamster cheek pouch oral cancer model. Optimization of BNCT depends largely on improving boron targeting to tumor cells. Seeking to maximize the potential of BNCT for the treatment for head and neck cancer, the aim of the present study was to perform boron biodistribution studies in the oral cancer model employing two different liposome formulations that were previously tested for a different pathology, i.e., in experimental mammary carcinoma in BALB/c mice: (1) MAC: liposomes incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the bilayer membrane and encapsulating a hypertonic buffer, administered intravenously at 6 mg B per kg body weight, and (2) MAC-TAC: liposomes incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the bilayer membrane and encapsulating a concentrated aqueous solution of the hydrophilic species Na3 [ae-B20H17NH3], administered intravenously at 18 mg B per kg body weight. Samples of tumor, precancerous and normal pouch tissue, spleen, liver, kidney, and blood were taken at different times post-administration and processed to measure boron content by inductively coupled plasma mass spectrometry. No ostensible clinical toxic effects were observed with the selected formulations. Both MAC and MAC-TAC delivered boron selectively to tumor tissue. Absolute tumor values for MAC-TAC peaked to 66.6 {+-} 16.1 ppm at 48 h and to 43.9 {+-} 17.6 ppm at 54 h with very favorable ratios of tumor boron relative to precancerous and normal tissue, making these protocols particularly worthy of radiobiological assessment. Boron concentration values obtained would result in therapeutic BNCT doses in tumor without exceeding radiotolerance in precancerous/normal tissue at the thermal neutron facility at RA-3.

  5. Reactive sputter deposition of boron nitride

    International Nuclear Information System (INIS)

    The preparation of fully dense, boron targets for use in planar magnetron sources has lead to the synthesis of Boron Nitride (BN) films by reactive rf sputtering. The deposition parameters of gas pressure, flow and composition are varied along with substrate temperature and applied bias. The films are characterized for composition using Auger electron spectroscopy, for chemical bonding using Raman spectroscopy and for crystalline structure using transmission electron microscopy. The deposition conditions are established which lead to the growth of crystalline BN phases. In particular, the growth of an adherent cubic BN coating requires 400--500 C substrate heating and an applied -300 V dc bias

  6. Neutrons around thick target bombarded by 50 MeV/u sup 1 sup 8 O-ion beam

    CERN Document Server

    Li, G; Li, Z; Su, Y; Zhang, S

    1999-01-01

    Neutron energy, fluence rate, angular distributions and dose equivalent rate distributions around thick Be, Cu, Au targets bombarded by a 50 MeV/u sup 1 sup 8 O-ion beam were measured by using a threshold detector activation method. The neutron yields and emission rates in the forward direction were obtained. (author)

  7. First boronization in KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S.H., E-mail: sukhhong@nfri.re.kr [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, K.S.; Kim, K.M.; Kim, H.T.; Kim, G.P. [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Sun, J.H.; Woo, H.J. [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Park, J.M.; Kim, W.C.; Kim, H.K.; Park, K.R.; Yang, H.L.; Na, H.K. [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Chung, K.S. [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of)

    2010-11-15

    First boronization in KSTAR is reported. KSTAR boronization system is based on a carborane (C{sub 2}B{sub 10}H{sub 12}) injection system. The design, construction, and test of the system are accomplished and it is tested by using a small vacuum vessel before it is mounted to a KSTAR port. After the boronization in KSTAR, impurity levels are significantly reduced by factor of 3 (oxygen) and by 10 (carbon). Characteristics of a-C/B:H thin films deposited by carborane vapor are investigated. Re-condensation of carborane vapor during the test phase has been reported.

  8. Mfge8 diminishes the severity of tissue fibrosis in mice by binding and targeting collagen for uptake by macrophages.

    Science.gov (United States)

    Atabai, Kamran; Jame, Sina; Azhar, Nabil; Kuo, Alex; Lam, Michael; McKleroy, William; Dehart, Greg; Rahman, Salman; Xia, Dee Dee; Melton, Andrew C; Wolters, Paul; Emson, Claire L; Turner, Scott M; Werb, Zena; Sheppard, Dean

    2009-12-01

    Milk fat globule epidermal growth factor 8 (Mfge8) is a soluble glycoprotein known to regulate inflammation and immunity by mediating apoptotic cell clearance. Since fibrosis can occur as a result of exaggerated apoptosis and inflammation, we set out to investigate the hypothesis that Mfge8 might negatively regulate tissue fibrosis. We report here that Mfge8 does decrease the severity of tissue fibrosis in a mouse model of pulmonary fibrosis; however, it does so not through effects on inflammation and apoptotic cell clearance, but by binding and targeting collagen for cellular uptake through its discoidin domains. Initial analysis revealed that Mfge8-/- mice exhibited enhanced pulmonary fibrosis after bleomycin-induced lung injury. However, they did not have increased inflammation or impaired apoptotic cell clearance after lung injury compared with Mfge8+/+ mice; rather, they had a defect in collagen turnover. Further experiments indicated that Mfge8 directly bound collagen and that Mfge8-/- macrophages exhibited defective collagen uptake that could be rescued by recombinant Mfge8 containing at least one discoidin domain. These data demonstrate a critical role for Mfge8 in decreasing the severity of murine tissue fibrosis by facilitating the removal of accumulated collagen. PMID:19884654

  9. Blogging in the Target Language: Review of the “Lang-8” Online Community

    OpenAIRE

    Judith Bündgens-Kosten

    2011-01-01

    Progress in language learning can be framed as the development of skills in four domains: reading, speaking, writing, and listening. While material to improve reading and listening skills is fairly easy to find, practicing productive skills outside the formal classroom can be more difficult. This is a review of language learning community, Lang-8 (www.lang-8.com).

  10. Blogging in the Target Language: Review of the “Lang-8” Online Community

    Directory of Open Access Journals (Sweden)

    Judith Bündgens-Kosten

    2011-06-01

    Full Text Available Progress in language learning can be framed as the development of skills in four domains: reading, speaking, writing, and listening. While material to improve reading and listening skills is fairly easy to find, practicing productive skills outside the formal classroom can be more difficult. This is a review of language learning community, Lang-8 (www.lang-8.com.

  11. Adsorption characteristics of arsenic and boron by soil

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, M.

    1986-01-01

    In order to obtain baseline data concerning the surface and ground water pollution caused by coal ash disposal, adsorption characteristics of arsenic (III) and boron by soil have been studied through laboratory experiments. The main results are as follows: (1) Arsenic (III) and boron adsorption on soil was strongly dependent on pH with adsorption maxima at pH 8 and 8-9, respectively. (2) Arsenic (III) and boron adsorption on soil over the entire concentration ranges investigated could be described by the Langmuir adsorption isotherm and the Freundlich adsorption isotherm, respectively. The Henry adsorption isotherm was also applicable over the lower concentration ranges of arsenic (III) and boron (As (III): < 0.1 deltag/ml; B: < 5deltag/ml.) (3) Arsenic (III) and boron adsorption on soil is controlled mainly by the contents of extractable Fe oxide and hydroxide for arsenic (III) and by the contents of extractable Al hydroxide and allophane (amorphous aluminium silicates) for boron. (4) Adsorption and movement of arsenic (III) and boron during the infiltration of coal ash leachate in soil layer were investigated by means of the unsteady-state, one-dimensional convective-diffusive mass transport model. This model is very useful for evaluation and prediction of the contamination of ground water by trace elements such as arsenic (III) and boron leached at coal ash disposal site.

  12. Aqueous compatible boron nitride nanosheets for high-performance hydrogels

    Science.gov (United States)

    Hu, Xiaozhen; Liu, Jiahui; He, Qiuju; Meng, Yuan; Cao, Liu; Sun, Ya-Ping; Chen, Jijie; Lu, Fushen

    2016-02-01

    Hexagonal boron nitride nanosheets (BNNSs) possess ultimate thermal and chemical stabilities and mechanical strengths. However, the unmodified BNNSs are hydrophobic and insoluble in water, which hinders their use in many technological areas requiring aqueous compatibility. In this work, h-BN was treated with molten citric acid to produce aqueous dispersible boron nitride sheets (ca-BNNSs). The resultant ca-BNNSs were used to fabricate ca-BNNS/polyacrylamide (i.e., BNNS2.5/PAAm) nanocomposite hydrogels, targeting high water retentivity and flexibility. The BNNS2.5/PAAm hydrogel (initially swollen in water) largely remained swollen (water content ~94 wt%) even after one-year storage under ambient conditions. Importantly, the swollen BNNS2.5/PAAm hydrogel (water content ~95 wt%) was highly flexible. Its elongation and compressive strength exceeded 10 000% and 8 MPa at 97% strain, respectively. Moreover, the aforementioned hydrogel recovered upon the removal of compression force, without obvious damage. The substantially improved water retentivity and flexibility revealed that BNNSs can serve as a promising new platform in the development of high-performance hydrogels.Hexagonal boron nitride nanosheets (BNNSs) possess ultimate thermal and chemical stabilities and mechanical strengths. However, the unmodified BNNSs are hydrophobic and insoluble in water, which hinders their use in many technological areas requiring aqueous compatibility. In this work, h-BN was treated with molten citric acid to produce aqueous dispersible boron nitride sheets (ca-BNNSs). The resultant ca-BNNSs were used to fabricate ca-BNNS/polyacrylamide (i.e., BNNS2.5/PAAm) nanocomposite hydrogels, targeting high water retentivity and flexibility. The BNNS2.5/PAAm hydrogel (initially swollen in water) largely remained swollen (water content ~94 wt%) even after one-year storage under ambient conditions. Importantly, the swollen BNNS2.5/PAAm hydrogel (water content ~95 wt%) was highly flexible. Its

  13. Zinc transporter 8 (ZnT8 expression is reduced by ischemic insults: a potential therapeutic target to prevent ischemic retinopathy.

    Directory of Open Access Journals (Sweden)

    Michael Deniro

    Full Text Available The zinc (Zn(++ transporter ZnT8 plays a crucial role in zinc homeostasis. It's been reported that an acute decrease in ZnT8 levels impairs β cell function and Zn(++ homeostasis, which contribute to the pathophysiology of diabetes mellitus (DM. Although ZnT8 expression has been detected in the retinal pigment epithelium (RPE, its expression profile in the retina has yet to be determined. Furthermore, the link between diabetes and ischemic retinopathy is well documented; nevertheless, the molecular mechanism(s of such link has yet to be defined. Our aims were to; investigate the expression profile of ZnT8 in the retina; address the influence of ischemia on such expression; and evaluate the influence of YC-1; (3-(50-hydroxymethyl-20-furyl-1-benzyl indazole, a hypoxia inducible factor-1 (HIF-1 inhibitor, on the status of ZnT8 expression. We used real-time RT-PCR, immunohistochemistry, and Western blot in the mouse model of oxygen-induced retinopathy (OIR and Müller cells to evaluate the effects of ischemia/hypoxia and YC-1 on ZnT8 expression. Our data indicate that ZnT8 was strongly expressed in the outer nuclear layer (ONL, outer plexiform layer (OPL, ganglion cell layer (GCL, and nerve fiber layer (NFL, whereas the photoreceptor layer (PRL, inner nuclear layer (INL and inner plexiform layer (IPL showed moderate ZnT8 immunoreactivity. Furthermore, we demonstrate that retinal ischemic insult induces a significant downregulation of ZnT8 at the message and protein levels, YC-1 rescues the injured retina by restoring the ZnT8 to its basal homeostatic levels in the neovascular retinas. Our data indicate that ischemic retinopathy maybe mediated by aberrant Zn(++ homeostasis caused by ZnT8 downregulation, whereas YC-1 plays a neuroprotective role against ischemic insult. Therefore, targeting ZnT8 provides a therapeutic strategy to combat neovascular eye diseases.

  14. Boron in sillimanite.

    Science.gov (United States)

    Grew, E S; Hinthorne, J R

    1983-08-01

    Sillimanite in six granulite-facies, kornerupine-bearing rocks contains 0.035 to 0.43 percent B(2)O(3) and 0.02 to 0.23 percent MgO (by weight). Substitution of boron for silicon and magnesium for aluminum is coupled such that the ratio of magnesium to boron is about 0.5. Sillimanite incorporates more than 0.1 percent B(2)O(3) only at high temperatures in a boron-rich environment at very low partial pressures of water. In the amphibolite facies, the sillimanite boron contents are too low to appreciably affect the stability relations of sillimanite with kyanite and andalusite. PMID:17830955

  15. Differential Expression and Function of PDE8 and PDE4 in Effector T cells: Implications for PDE8 as a Drug Target in Inflammation.

    Science.gov (United States)

    Vang, Amanda G; Basole, Chaitali; Dong, Hongli; Nguyen, Rebecca K; Housley, William; Guernsey, Linda; Adami, Alexander J; Thrall, Roger S; Clark, Robert B; Epstein, Paul M; Brocke, Stefan

    2016-01-01

    Abolishing the inhibitory signal of intracellular cAMP is a prerequisite for effector T (Teff) cell function. The regulation of cAMP within leukocytes critically depends on its degradation by cyclic nucleotide phosphodiesterases (PDEs). We have previously shown that PDE8A, a PDE isoform with 40-100-fold greater affinity for cAMP than PDE4, is selectively expressed in Teff vs. regulatory T (Treg) cells and controls CD4(+) Teff cell adhesion and chemotaxis. Here, we determined PDE8A expression and function in CD4(+) Teff cell populations in vivo. Using magnetic bead separation to purify leukocyte populations from the lung draining hilar lymph node (HLN) in a mouse model of ovalbumin-induced allergic airway disease (AAD), we found by Western immunoblot and quantitative (q)RT-PCR that PDE8A protein and gene expression are enhanced in the CD4(+) T cell fraction over the course of the acute inflammatory disease and recede at the late tolerant non-inflammatory stage. To evaluate PDE8A as a potential drug target, we compared the selective and combined effects of the recently characterized highly potent PDE8-selective inhibitor PF-04957325 with the PDE4-selective inhibitor piclamilast (PICL). As previously shown, PF-04957325 suppresses T cell adhesion to endothelial cells. In contrast, we found that PICL alone increased firm T cell adhesion to endothelial cells by ~20% and significantly abrogated the inhibitory effect of PF-04957325 on T cell adhesion by over 50% when cells were co-exposed to PICL and PF-04957325. Despite its robust effect on T cell adhesion, PF-04957325 was over two orders of magnitude less efficient than PICL in suppressing polyclonal Teff cell proliferation, and showed no effect on cytokine gene expression in these cells. More importantly, PDE8 inhibition did not suppress proliferation and cytokine production of myelin-antigen reactive proinflammatory Teff cells in vivo and in vitro. Thus, targeting PDE8 through PF-04957325 selectively regulates Teff

  16. Boron nitride composites

    Energy Technology Data Exchange (ETDEWEB)

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2016-02-16

    According to one embodiment, a composite product includes hexagonal boron nitride (hBN), and a plurality of cubic boron nitride (cBN) particles, wherein the plurality of cBN particles are dispersed in a matrix of the hBN. According to another embodiment, a composite product includes a plurality of cBN particles, and one or more borate-containing binders.

  17. Channeling of boron ions into silicon

    International Nuclear Information System (INIS)

    Channeled and random distributions of boron ions implanted over the energy range 50 keV--1.8 MeV into silicon have been measured using the differential capacitance technique. When implantations are performed along the or axis, profiles exhibit a strong orientation dependance. The best channeled profiles shows that more than 70% of the implanted dose is in the channeled peak

  18. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    International Nuclear Information System (INIS)

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7, and increases with an increase in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration

  19. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dooseong; Choi, Hei Min; Lee, Kune Woo; Moon Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7, and increases with an increase in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration.

  20. Folate Functionalized Boron Nitride Nanotubes and their Selective Uptake by Glioblastoma Multiforme Cells: Implications for their Use as Boron Carriers in Clinical Boron Neutron Capture Therapy

    Science.gov (United States)

    2009-01-01

    Boron neutron capture therapy (BNCT) is increasingly being used in the treatment of several aggressive cancers, including cerebral glioblastoma multiforme. The main requirement for this therapy is selective targeting of tumor cells by sufficient quantities of10B atoms required for their capture/irradiation with low-energy thermal neutrons. The low content of boron targeting species in glioblastoma multiforme accounts for the difficulty in selective targeting of this very malignant cerebral tumor by this radiation modality. In the present study, we have used for the first time boron nitride nanotubes as carriers of boron atoms to overcome this problem and enhance the selective targeting and ablative efficacy of BNCT for these tumors. Following their dispersion in aqueous solution by noncovalent coating with biocompatible poly-l-lysine solutions, boron nitride nanotubes were functionalized with a fluorescent probe (quantum dots) to enable their tracking and with folic acid as selective tumor targeting ligand. Initial in vitro studies have confirmed substantive and selective uptake of these nanovectors by glioblastoma multiforme cells, an observation which confirms their potential clinical application for BNCT therapy for these malignant cerebral tumors. PMID:20596476

  1. Enhanced surface hardness by boron implantation in Nitinol alloy.

    Science.gov (United States)

    Lee, D H; Park, B; Saxena, A; Serene, T P

    1996-10-01

    Boron implantation into Nitinol alloy has a potential for developing improved Nitinol root canal instruments with excellent cutting properties, without affecting their superelastic bulk-mechanical properties. The surface hardness of nickel-titanium (NiTi) alloy, also known as "Nitinol" (50 atm% nickel+50 atm% titanium), has been improved by ion-beam surface modification. With an implantation dose of 4.8 x 10(17) boron/cm2, a high concentration of boron (30 atm%) is incorporated into NiTi alloy by 110 keV boron ions at room temperature (25 degrees C). Boron-implanted and unimplanted (pure) Nitinol alloys show surface hardness of 7.6 +/- 0.2 and 3.2 +/- 0.2 GPa, respectively, at the nanoindentation depth of 0.05 micron. The ion-beam-modified NiTi alloy exceeds the surface hardness of stainless steel. PMID:9198443

  2. Synthesis of well-aligned boron nanowires and their structural stability under high pressure

    CERN Document Server

    Cao Li Min; Gao Cun Xiao; Li Yan Cun; Li Xiao Dong; Wang, Y Q; Zhang, Z; Cui Qi Liang; Zou Guang Tian; Sun Li; Wang Wen Kui

    2002-01-01

    Owing to its unusual bonding and vast variety of unique crystal structures, boron is one of the most fascinating elements in the periodic table. Here we report the large-scale synthesis of well-ordered boron nanowires and their structural stability at high pressure. Boron nanowires with uniform diameter and length grown vertically on silicon substrates were synthesized by radio-frequency magnetron sputtering with a target of pure boron using argon as the sputtering atmosphere without involvement of templates and catalysts. Detailed characterization by high-resolution transmission electron microscopy and electron diffraction indicates that the boron nanowires are amorphous. Structural stability of the boron nanowires at room temperature has been investigated by means of in situ high-pressure energy-dispersive x-ray powder diffraction using synchrotron radiation in a diamond anvil cell. No crystallization was observed up to a pressure of 103.5 GPa, suggesting that the amorphous structure of boron nanowires is s...

  3. The investigation of parameters affecting boron removal by electrocoagulation method

    International Nuclear Information System (INIS)

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm2. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl2. Added CaCl2 increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions

  4. The investigation of parameters affecting boron removal by electrocoagulation method

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey)]. E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey); Kocakerim, M. Muhtar [Department of Chemical Engineering, 25240, Atatuerk University, Faculty of Engineering Erzurum (Turkey); Keskinler, Buelent [Department of Environmental Engineering, Gebze Institute of Technology, Gebze/Kocaeli 41400 (Turkey)

    2005-10-17

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm{sup 2}. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl{sub 2}. Added CaCl{sub 2} increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions.

  5. Boron Speciation in Soda-Lime Borosilicate Glasses Containing Zirconium

    International Nuclear Information System (INIS)

    Boron speciation was investigated in soda-lime borosilicate glass containing zirconium. In such compositions, competition between charge compensators (here, sodium and calcium) can occur for the compensation of tetrahedral boron or octahedral zirconium units. 11B MAS NMR is particularly suitable for obtaining data on preferential compensation behavior that directly affects the boron coordination number. In addition to the classical proportions of tri- and tetrahedral boron, additional data can be obtained on the contributions involved in these two coordination numbers. An approach is described here based on simultaneous MAS spectrum analysis of borosilicate glass with variable Zr/Si and Ca/Na ratios at two magnetic field strengths (11. 7 and 18. 8 T), with constraints arising from MQMAS spectroscopy, detailed analysis of satellite transitions, and spin-echo experiments. New possibilities of 11B NMR were presented for improving the identification and quantification of the different contributions involved in tri- and tetrahedral boron coordination. Both NMR and Raman revealed a trend of decreased tetrahedral boron proportion with the increase of Ca/Na ratio or the Zr/Si ratio. This strongly suggests that zirconium compensation takes preference over boron compensation, and that zirconium and boron are both compensated mainly by sodium rather than calcium. (authors)

  6. Boron Removal in Seawater Reverse Osmosis System

    KAUST Repository

    Rahmawati, Karina

    2011-07-01

    Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

  7. Boron isotope method for study of seawater intrusion

    Institute of Scientific and Technical Information of China (English)

    肖应凯; 尹德忠; 刘卫国; 王庆忠; 魏海珍

    2001-01-01

    A distinct difference in boron isotopes between seawater and terrestrial water is emphasized by δ11B values reported for seawater and groundwater, with an average of 38.8‰ and in the range of -8.9‰ to 9.8‰, respectively. The isotopic composition of boron in groundwater can be used to quantify seawater intrusion and identify intrusion types, e.g. seawater or brine intrusions with different chemical and isotopic characteristics, by using the relation of δ11B and chloride concentration. The feasibility of utilizing boron isotope in groundwater for studying seawater intrusion in Laizhou Bay Region, China, is reported in this study, which shows that boron isotope is a useful and excellent tool for the study of seawater intrusion.

  8. Boronated liposome development and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M.F. [Univ. of California, Los Angeles, CA (United States)

    1995-11-01

    The boronated liposome development and evaluation effort consists of two separate tasks. The first is the development of new boron compounds and the synthesis of known boron species with BNCT potential. These compounds are then encapsulated within liposomes for the second task, biodistribution testing in tumor-bearing mice, which examines the potential for the liposomes and their contents to concentrate boron in cancerous tissues.

  9. NMR insights into dynamics regulated target binding of DLC8 dimer

    International Nuclear Information System (INIS)

    Conformational dynamics play a crucial role in biological function. Dynein light chain protein (DLC8) acts as a cargo adaptor, and exists as a dimer under physiological conditions and dissociates into monomer below pH 4. In the present NMR study, we identified some dynamic residues in the dimer using chemical shift perturbation approach by applying small pH change. As evidenced by gel filtration and CD studies, this small pH change does not alter the globular structural features of the protein. In fact, these changes result in small local stability perturbations as monitored using temperature dependence of amide proton chemical shifts, and influence the dynamics of the dimer substantially. Further, interaction studies of the protein with a peptide containing the recognition motif of cargo indicated that the efficacy of peptide binding decreases when the pH is reduced from 7 to 6. These observations taken together support the conception that dynamics can regulate cargo binding/trafficking by the DLC8 dimer

  10. Superior control of HIV-1 replication by CD8+ T cells targeting conserved epitopes: implications for HIV vaccine design.

    Directory of Open Access Journals (Sweden)

    Pratima Kunwar

    Full Text Available A successful HIV vaccine will likely induce both humoral and cell-mediated immunity, however, the enormous diversity of HIV has hampered the development of a vaccine that effectively elicits both arms of the adaptive immune response. To tackle the problem of viral diversity, T cell-based vaccine approaches have focused on two main strategies (i increasing the breadth of vaccine-induced responses or (ii increasing vaccine-induced responses targeting only conserved regions of the virus. The relative extent to which set-point viremia is impacted by epitope-conservation of CD8(+ T cell responses elicited during early HIV-infection is unknown but has important implications for vaccine design. To address this question, we comprehensively mapped HIV-1 CD8(+ T cell epitope-specificities in 23 ART-naïve individuals during early infection and computed their conservation score (CS by three different methods (prevalence, entropy and conseq on clade-B and group-M sequence alignments. The majority of CD8(+ T cell responses were directed against variable epitopes (p<0.01. Interestingly, increasing breadth of CD8(+ T cell responses specifically recognizing conserved epitopes was associated with lower set-point viremia (r = - 0.65, p = 0.009. Moreover, subjects possessing CD8(+ T cells recognizing at least one conserved epitope had 1.4 log10 lower set-point viremia compared to those recognizing only variable epitopes (p = 0.021. The association between viral control and the breadth of conserved CD8(+ T cell responses may be influenced by the method of CS definition and sequences used to determine conservation levels. Strikingly, targeting variable versus conserved epitopes was independent of HLA type (p = 0.215. The associations with viral control were independent of functional avidity of CD8(+ T cell responses elicited during early infection. Taken together, these data suggest that the next-generation of T-cell based HIV-1 vaccines should focus

  11. Experimental Cross Sections for Reactions of Heavy Ions and sup 2 sup 0 sup 8 Pb, sup 2 sup 0 sup 9 Bi, sup 2 sup 3 sup 8 U, and sup 2 sup 4 sup 8 Cm Targets

    CERN Document Server

    Patin, J B

    2002-01-01

    The study of the reactions between heavy ions and sup 2 sup 0 sup 8 Pb, sup 2 sup 0 sup 9 Bi, sup 2 sup 3 sup 8 U, and sup 2 sup 4 sup 8 Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the sup 2 sup 3 sup 8 U( sup 1 sup 8 O,xn) sup 2 sup 5 sup 6 sup - sup x Fm, sup 2 sup 3 sup 8 U( sup 2 sup 2 Ne,xn) sup 2 sup 6 sup 0 sup - sup x No, and sup 2 sup 4 sup 8 Cm( sup 1 sup 5 N,xn) sup 2 sup 6 sup 3 sup - sup x Lr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf ...

  12. CCL8/MCP-2 is a target for mir-146a in HIV-1-infected human microglial cells

    OpenAIRE

    Rom, Slava; Rom, Inna; Passiatore, Giovanni; Pacifici, Marco; Radhakrishnan, Sujatha; Del Valle, Luis; Piña-Oviedo, Sergio; Khalili, Kamel; Eletto, Davide; Peruzzi, Francesca

    2010-01-01

    MicroRNA-mediated regulation of gene expression appears to be involved in a variety of cellular processes, including development, differentiation, proliferation, and apoptosis. Mir-146a is thought to be involved in the regulation of the innate immune response, and its expression is increased in tissues associated with chronic inflammation. Among the predicted gene targets for mir-146a, the chemokine CCL8/MCP-2 is a ligand for the CCR5 chemokine receptor and a potent inhibitor of CD4/CCR5-medi...

  13. TRPM7 and TRPM8 Ion Channels in Pancreatic Adenocarcinoma: Potential Roles as Cancer Biomarkers and Targets

    Directory of Open Access Journals (Sweden)

    Nelson S. Yee

    2012-01-01

    Full Text Available Transient receptor potential (TRP ion channels are essential for normal functions and health by acting as molecular sensors and transducing various stimuli into cellular and physiological responses. Growing evidence has revealed that TRP ion channels play important roles in a wide range of human diseases, including malignancies. In light of recent discoveries, it has been found that TRP melastatin-subfamily members, TRPM7 and TRPM8, are required for normal and cancerous development of exocrine pancreas. We are currently investigating the mechanisms which mediate the functional roles of TRPM7 and TRPM8 and attempting to develop these ion channels as clinical biomarkers and therapeutic targets for achieving the goal of personalized therapy in pancreatic cancer.

  14. Boron site preference in ternary Ta and Nb boron silicides

    International Nuclear Information System (INIS)

    X-ray single crystal (XSC) and neutron powder diffraction data (NPD) were used to elucidate boron site preference for five ternary phases. Ta3Si1−xBx (x=0.112(4)) crystallizes with the Ti3P-type (space group P42/n) with B-atoms sharing the 8g site with Si atoms. Ta5Si3−x (x=0.03(1); Cr5B3- type) crystallizes with space group I4/mcm, exhibiting a small amount of vacancies on the 4a site. Both, Ta5(Si1−xBx)3, x=0.568(3), and Nb5(Si1−xBx)3, x=0.59(2), are part of solid solutions of M5Si3 with Cr5B3-type into the ternary M–Si–B systems (M=Nb or Ta) with B replacing Si on the 8h site. The D88-phase in the Nb–Si–B system crystallizes with the Ti5Ga4-type revealing the formula Nb5Si3B1−x (x=0.292(3)) with B partially filling the voids in the 2b site of the Mn5Si3 parent type. - Graphical abstract: The crystal structures of a series of compounds have been solved from X-ray single crystal diffractometry revealing details on the boron incorporation. Highlights: ► Structure of a series of compounds have been solved by X-ray single crystal diffractometry. ► Ta3(Si1−xBx) (x=0.112) crystallizes with the Ti3P-type, B and Si atoms randomly share the 8g site. ► Structure of Nb5Si3B1−x (x=0.292; Ti5Ga4-type) was solved from NPD.

  15. Mammalian Target of Rapamycin Complex 2 Controls CD8 T Cell Memory Differentiation in a Foxo1-Dependent Manner.

    Science.gov (United States)

    Zhang, Lianjun; Tschumi, Benjamin O; Lopez-Mejia, Isabel C; Oberle, Susanne G; Meyer, Marten; Samson, Guerric; Rüegg, Markus A; Hall, Michael N; Fajas, Lluis; Zehn, Dietmar; Mach, Jean-Pierre; Donda, Alena; Romero, Pedro

    2016-02-01

    Upon infection, antigen-specific naive CD8 T cells are activated and differentiate into short-lived effector cells (SLECs) and memory precursor cells (MPECs). The underlying signaling pathways remain largely unresolved. We show that Rictor, the core component of mammalian target of rapamycin complex 2 (mTORC2), regulates SLEC and MPEC commitment. Rictor deficiency favors memory formation and increases IL-2 secretion capacity without dampening effector functions. Moreover, mTORC2-deficient memory T cells mount more potent recall responses. Enhanced memory formation in the absence of mTORC2 was associated with Eomes and Tcf-1 upregulation, repression of T-bet, enhanced mitochondrial spare respiratory capacity, and fatty acid oxidation. This transcriptional and metabolic reprogramming is mainly driven by nuclear stabilization of Foxo1. Silencing of Foxo1 reversed the increased MPEC differentiation and IL-2 production and led to an impaired recall response of Rictor KO memory T cells. Therefore, mTORC2 is a critical regulator of CD8 T cell differentiation and may be an important target for immunotherapy interventions. PMID:26804903

  16. Boron cures cancer

    International Nuclear Information System (INIS)

    In this work the authors cite a few examples of the use of radiopharmaceuticals for diagnostic and therapeutic purposes in nuclear medicine. They point to the possibility of boron neutron capture therapy and the use for the neutron capture therapy of other light elements.

  17. Explicitly correlated wave function for a boron atom

    CERN Document Server

    Puchalski, Mariusz; Pachucki, Krzysztof

    2015-01-01

    We present results of high-precision calculations for a boron atom's properties using wave functions expanded in the explicitly correlated Gaussian basis. We demonstrate that the well-optimized 8192 basis functions enable a determination of energy levels, ionization potential, and fine and hyperfine splittings in atomic transitions with nearly parts per million precision. The results open a window to a spectroscopic determination of nuclear properties of boron including the charge radius of the proton halo in the $^8$B nucleus.

  18. Technology strategy for gas technologies; Technology Target Areas; TTA8 Gas Technology

    Energy Technology Data Exchange (ETDEWEB)

    2008-07-01

    TTA8 - Gas technologies points out the various routes Norway can follow to capitalise on the vast resources of natural gas that will be produced in the years to come by developing a strong technology and competence platform. A broad view is taken for the value creation having as basis the continued gas export from NCS to Europe, but also a strong focus on development of gas resources in other parts of the world. The latter can also be seen as part of international positioning for upstream resources and does also include involvements in projects, and export of technology and products. The TTA has structured the analysis into 3 main areas: Gas transport and processing (pipeline, LNG, other); Gas conversion to fuels, chemicals and materials; CO{sub 2} management. In this report, for each of these areas, scenarios based on a gap analysis are presented. One of the key goals has been to identify pacing and emerging technologies for the next 20 years. Based on this, technologies have been mapped according to importance for future competitiveness and technology ambitions. This also includes primary funding responsibilities (public and/or industry). The road map below reflects the key issues in the proposed strategy. The base level of the figure explains areas that will have to be pursued to maintain Norway's role as a key gas and gas technology provider. The second layer represents near term options and possibilities with a reasonable risk profile that could further enhance the Norwegian position given the resources and drive to further develop this industry. As the top layer we have selected some of our 'dreams', what we may achieve if a progressive approach is followed with a strongly innovation based policy. It is acknowledged by the TTA that Norway cannot be a leading technology player in all aspects of the gas value chain. For some technologies we should be an active player and developer, whilst for other technologies we should become a competent buyer

  19. Boron contamination in drinking - irrigation water and boron removal methods

    Directory of Open Access Journals (Sweden)

    Meltem Bilici Başkan

    2014-03-01

    Full Text Available Boron presents in IIIA group of periodic table and has high ionization capacity. Therefore it is classified as a metalloid. Average boron concentration in earth's crust is 10 mg/kg. It presents in the environment as a salts of Ca, Na, and Mg. Boron reserves having high concentration and economical extent are found mostly in Turkey and in arid, volcanic and high hydrothermal activity regions of U.S. as compounds of boron attached to oxygen. Boron is an essential micronutrient for plants, although it may be toxic at higher levels. The range in which it is converted from a nutrient to a contaminant is quite narrow. Boron presents in water environment as a boric acid and rarely borate salts. The main boron sources, whose presence is detected in surface waters, are urban wastes and industrial wastes, which can come from a wide range of different activities as well as several chemical products used in agriculture. In Turkey, the most pollutant toxic element in drinking and irrigation water is boron. Therefore boron removal is very important in terms of human health and agricultural products in high quality. Mainly boron removal methods from drinking water and irrigation water are ion exchange, ultrafiltration, reverse osmosis, and adsorption.

  20. Process for microwave sintering boron carbide

    International Nuclear Information System (INIS)

    A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy

  1. Methods of producing continuous boron carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. SU-D-304-07: Application of Proton Boron Fusion Reaction to Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, J; Yoon, D; Shin, H; Kim, M; Suh, T [The Catholic University Seoul (Korea, Republic of)

    2015-06-15

    Purpose: we present the introduction of a therapy method using the proton boron fusion reaction. The purpose of this study is to verify the theoretical validity of proton boron fusion therapy using Monte Carlo simulations. Methods: After boron is accumulated in the tumor region, the emitted from outside the body proton can react with the boron in the tumor region. An increase of the proton’s maximum dose level is caused by the boron and only the tumor cell is damaged more critically. In addition, a prompt gamma ray is emitted from the proton boron reaction point. Here we show that the effectiveness of the proton boron fusion therapy (PBFT) was verified using Monte Carlo simulations. Results: We found that a dramatic increase by more than half of the proton’s maximum dose level was induced by the boron in the tumor region. This increase occurred only when the proton’s maximum dose point was located within the boron uptake region (BUR). In addition, the 719 keV prompt gamma ray peak produced by the proton boron fusion reaction was positively detected. Conclusion: This therapy method features the advantages such as the application of Bragg-peak to the therapy, the accurate targeting of tumor, improved therapy effects, and the monitoring of the therapy region during treatment.

  3. Boron-10 ABUNCL Models of Fuel Testing

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, Edward R.; Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.

    2013-10-01

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from MCNP simulations of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) active configuration model with fuel pins previously measured at Los Alamos National Laboratory. A comparison of the GE-ABUNCL simulations and simulations of 3He based UNCL-II active counter (the system for which the GE-ABUNCL was targeted to replace) with the same fuel pin assemblies is also provided.

  4. Channeling of boron ions into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lecrosnier, D.; Paugam, J.; Gallou, J.

    1977-04-01

    Channeled and random distributions of boron ions implanted over the energy range 50 keV--1.8 MeV into silicon have been measured using the differential capacitance technique. When implantations are performed along the <110> or <111> axis, profiles exhibit a strong orientation dependance. The best channeled profiles shows that more than 70% of the implanted dose is in the channeled peak.

  5. An empirical model for parameters affecting energy consumption in boron removal from boron-containing wastewaters by electrocoagulation

    International Nuclear Information System (INIS)

    In this study, it was investigated parameters affecting energy consumption in boron removal from boron containing wastewaters prepared synthetically, via electrocoagulation method. The solution pH, initial boron concentration, dose of supporting electrolyte, current density and temperature of solution were selected as experimental parameters affecting energy consumption. The obtained experimental results showed that boron removal efficiency reached up to 99% under optimum conditions, in which solution pH was 8.0, current density 6.0mA/cm2, initial boron concentration 100mg/L and solution temperature 293K. The current density was an important parameter affecting energy consumption too. High current density applied to electrocoagulation cell increased energy consumption. Increasing solution temperature caused to decrease energy consumption that high temperature decreased potential applied under constant current density. That increasing initial boron concentration and dose of supporting electrolyte caused to increase specific conductivity of solution decreased energy consumption. As a result, it was seen that energy consumption for boron removal via electrocoagulation method could be minimized at optimum conditions. An empirical model was predicted by statistically. Experimentally obtained values were fitted with values predicted from empirical model being as following;[ECB]=7.6x106x[OH]0.11x[CD]0.62x[IBC]-0.57x[DSE]-0.04x[T] -2.98x[t] Unfortunately, the conditions obtained for optimum boron removal were not the conditions obtained for minimum energy consumption. It was determined that support electrolyte must be used for increase boron removal and decrease electrical energy consumption.

  6. An empirical model for parameters affecting energy consumption in boron removal from boron-containing wastewaters by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey)]. E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey)

    2007-06-01

    In this study, it was investigated parameters affecting energy consumption in boron removal from boron containing wastewaters prepared synthetically, via electrocoagulation method. The solution pH, initial boron concentration, dose of supporting electrolyte, current density and temperature of solution were selected as experimental parameters affecting energy consumption. The obtained experimental results showed that boron removal efficiency reached up to 99% under optimum conditions, in which solution pH was 8.0, current density 6.0mA/cm{sup 2}, initial boron concentration 100mg/L and solution temperature 293K. The current density was an important parameter affecting energy consumption too. High current density applied to electrocoagulation cell increased energy consumption. Increasing solution temperature caused to decrease energy consumption that high temperature decreased potential applied under constant current density. That increasing initial boron concentration and dose of supporting electrolyte caused to increase specific conductivity of solution decreased energy consumption. As a result, it was seen that energy consumption for boron removal via electrocoagulation method could be minimized at optimum conditions. An empirical model was predicted by statistically. Experimentally obtained values were fitted with values predicted from empirical model being as following;[ECB]=7.6x10{sup 6}x[OH]{sup 0.11}x[CD]{sup 0.62}x[IBC]{sup -0.57}x[DSE]{sup -0.}= {sup 04}x[T]{sup -2.98}x[t] Unfortunately, the conditions obtained for optimum boron removal were not the conditions obtained for minimum energy consumption. It was determined that support electrolyte must be used for increase boron removal and decrease electrical energy consumption.

  7. Center-cut separation of intermediately adsorbing target component by 8-zone simulated moving bed chromatography with internal recycle.

    Science.gov (United States)

    Kiwala, Dawid; Mendrella, Jadwiga; Antos, Dorota; Seidel-Morgenstern, Andreas

    2016-07-01

    An 8-zone simulated moving bed chromatography with internal recycle (8ZSMB-IR) has been designed for center-cut separation, that is, for isolating an intermediately adsorbed component out of a multicomponent mixture. The system consists of two integrated subunits and operates in a fully continuous manner. In the first subunit the feed mixture is split into two fractions containing either a single component or a binary mixture. The binary mixture is recycled through the internal raffinate or extract port into the second subunit, where the target product is isolated. Additionally, the solvent is also recycled internally. For a case study, the separation of a ternary mixture of cycloketones as a model system under weakly non-linear isotherm conditions has been investigated. A few novel configurations of the 8ZSMB-IR unit including the arrangement of the internal recycle of extract, raffinate and solvent streams between two subunits have been examined with respect to various performance indicators for the process realization. The unit performed best with the developed configuration when the internal raffinate stream was recycled and the solvent recycling loop was closed between the last and the first zone of the first subunit. That configuration has further been analyzed experimentally and numerically. On the basis of the results a strategy for determining reliable operating conditions for the 8ZSMB-IR process has been developed. The procedure exploited a model of the process dynamics, which was implemented to refine the isotherm coefficients and to quantify the mixing effect of the liquid stream inside the recycling loops. The upgraded model with the adjusted parameters has been validated based on experimental data and successfully applied for optimizing the operating conditions of the separation. PMID:27260199

  8. Convergent multi-miRNA Targeting of ApoE Drives LRP1/LRP8-Dependent Melanoma Metastasis and Angiogenesis

    Science.gov (United States)

    Pencheva, Nora; Tran, Hien; Buss, Colin; Huh, Doowon; Drobnjak, Marija; Busam, Klaus; Tavazoie, Sohail F.

    2013-01-01

    SUMMARY Through in-vivo selection of human cancer cell populations, we uncover a convergent and cooperative miRNA network that drives melanoma metastasis. We identify miR-1908, miR-199a-5p, and miR-199a-3p as endogenous promoters of metastatic invasion, angiogenesis, and colonization in melanoma. These miRNAs convergently target Apolipoprotein E (ApoE) and the heat-shock factor DNAJA4. Cancer-secreted ApoE suppresses invasion and metastatic endothelial recruitment (MER) by engaging melanoma-cell LRP1 and endothelial-cell LRP8 receptors, respectively–while DNAJA4 promotes ApoE expression. Expression levels of these miRNAs and ApoE correlate with human metastatic progression outcomes. Treatment of cells with locked nucleic acids (LNAs) targeting these miRNAs inhibits metastasis to multiple organs, while therapeutic delivery of these LNAs strongly suppresses melanoma metastasis. We thus identify miRNAs with dual cell-intrinsic/cell-extrinsic roles in cancer, reveal convergent cooperativity in a metastatic miRNA network, identify ApoE as an anti-angiogenic and metastasis-suppressive factor, and uncover multiple prognostic miRNAs with synergistic combinatorial therapeutic potential in melanoma. PMID:23142051

  9. Convergent multi-miRNA targeting of ApoE drives LRP1/LRP8-dependent melanoma metastasis and angiogenesis.

    Science.gov (United States)

    Pencheva, Nora; Tran, Hien; Buss, Colin; Huh, Doowon; Drobnjak, Marija; Busam, Klaus; Tavazoie, Sohail F

    2012-11-21

    Through in vivo selection of human cancer cell populations, we uncover a convergent and cooperative miRNA network that drives melanoma metastasis. We identify miR-1908, miR-199a-5p, and miR-199a-3p as endogenous promoters of metastatic invasion, angiogenesis, and colonization in melanoma. These miRNAs convergently target apolipoprotein E (ApoE) and the heat shock factor DNAJA4. Cancer-secreted ApoE suppresses invasion and metastatic endothelial recruitment (MER) by engaging melanoma cell LRP1 and endothelial cell LRP8 receptors, respectively, while DNAJA4 promotes ApoE expression. Expression levels of these miRNAs and ApoE correlate with human metastatic progression outcomes. Treatment of cells with locked nucleic acids (LNAs) targeting these miRNAs inhibits metastasis to multiple organs, and therapeutic delivery of these LNAs strongly suppresses melanoma metastasis. We thus identify miRNAs with dual cell-intrinsic/cell-extrinsic roles in cancer, reveal convergent cooperativity in a metastatic miRNA network, identify ApoE as an anti-angiogenic and metastasis-suppressive factor, and uncover multiple prognostic miRNAs with synergistic combinatorial therapeutic potential in melanoma. PMID:23142051

  10. Study of characteristics for heavy water photoneutron source in boron neutron capture therapy

    CERN Document Server

    Salehi, Danial; Sardari, Dariush

    2013-01-01

    Bremsstrahlung photon beams produced by medical linear accelerators are currently the most commonly used method of radiation therapy for cancerous tumors. Photons with energies greater than 8-10 MeV potentially generate neutrons through photonuclear interactions in the accelerator's treatment head, patient's body, and treatment room ambient. Electrons impinging on a heavy target generate a cascade shower of bremsstrahlung photons, the energy spectrum of which shows an end point equal to the electron beam energy. By varying the target thickness, an optimum thickness exists for which, at the given electron energy, maximum photon flux is achievable. If a source of high-energy photons i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel approach for production of an acceptable flux of filterable photoneturons for boron neutron capture therapy (BNCT) application is possible. This study consists of two parts. 1. Comparison and assessment of deuterium photonuclear cross section data. 2. Ev...

  11. Wafer-Scale and Wrinkle-Free Epitaxial Growth of Single-Orientated Multilayer Hexagonal Boron Nitride on Sapphire.

    Science.gov (United States)

    Jang, A-Rang; Hong, Seokmo; Hyun, Chohee; Yoon, Seong In; Kim, Gwangwoo; Jeong, Hu Young; Shin, Tae Joo; Park, Sung O; Wong, Kester; Kwak, Sang Kyu; Park, Noejung; Yu, Kwangnam; Choi, Eunjip; Mishchenko, Artem; Withers, Freddie; Novoselov, Kostya S; Lim, Hyunseob; Shin, Hyeon Suk

    2016-05-11

    Large-scale growth of high-quality hexagonal boron nitride has been a challenge in two-dimensional-material-based electronics. Herein, we present wafer-scale and wrinkle-free epitaxial growth of multilayer hexagonal boron nitride on a sapphire substrate by using high-temperature and low-pressure chemical vapor deposition. Microscopic and spectroscopic investigations and theoretical calculations reveal that synthesized hexagonal boron nitride has a single rotational orientation with AA' stacking order. A facile method for transferring hexagonal boron nitride onto other target substrates was developed, which provides the opportunity for using hexagonal boron nitride as a substrate in practical electronic circuits. A graphene field effect transistor fabricated on our hexagonal boron nitride sheets shows clear quantum oscillation and highly improved carrier mobility because the ultraflatness of the hexagonal boron nitride surface can reduce the substrate-induced degradation of the carrier mobility of two-dimensional materials. PMID:27120101

  12. Determination of boron in nuclear materials at subppm levels by high pressure liquid chromatography (HPLC)

    International Nuclear Information System (INIS)

    Experiments were conducted for the determination of boron in U3O8 powder, aluminium metal and milliQ water using dynamically modified Reversed Phase High Pressure Liquid Chromatography (RP-HPLC) and using two precolumn chromogenic agents viz. chromotropic acid and curcumin for complexing boron. The complex was separated from the excess of reagent and determined by HPLC. When present in subppm levels, chromotropic acid was used successfully only for determination boron in water samples. For determination of boron at subppm levels in uranium and aluminium samples, curcumin was used as the precolumn chromogenic agent. The boron curcumin complex (rosocyanin) was formed after extraction of boron with 2-ethyl-l, 3-hexane diol (EHD). The rosocyanin complex was then separated from excess curcumin by displacement chromatography. Linear calibration curves for boron amounts in the range of 0.02 μg to 0.5 μg were developed with correlation coefficients varying from 0.997 to 0.999 and were used for the determination of boron in aluminium and uranium samples. Precision of about 10% was achieved in samples containing less than 1 ppmw of boron. Detection limit of this method is 0.01 μg boron. (author)

  13. Sintered boron, production and properties

    International Nuclear Information System (INIS)

    Microhardness HV, tensile properties and Young modulus of sintered boron of different porosity were studied. It was shown that with density growth tensile properties improve. HV and brittle-ductile transition temperature Tsub(b) of sintered boron on the one hand and for silicon and titanium carbide on the other were compared and discussed. It was noted that the general level of HV and Tsub(b) for boron is rather high and at similar relative temperatures these characteristics are much higher. Temperature dependences of linear expansion coefficient, thermal capacity, thermal and temperature conductivity of sintered boron of 20% porosity were studied. Gruneisen parameter was evaluated

  14. Fivefold twinned boron carbide nanowires.

    Science.gov (United States)

    Fu, Xin; Jiang, Jun; Liu, Chao; Yuan, Jun

    2009-09-01

    Chemical composition and crystal structure of fivefold twinned boron carbide nanowires have been determined by electron energy-loss spectroscopy and electron diffraction. The fivefold cyclic twinning relationship is confirmed by systematic axial rotation electron diffraction. Detailed chemical analysis reveals a carbon-rich boron carbide phase. Such boron carbide nanowires are potentially interesting because of their intrinsic hardness and high temperature thermoelectric property. Together with other boron-rich compounds, they may form a set of multiply twinned nanowire systems where the misfit strain could be continuously tuned to influence their mechanical properties. PMID:19687534

  15. RNA Interference-Guided Targeting of Hepatitis C Virus Replication with Antisense Locked Nucleic Acid-Based Oligonucleotides Containing 8-oxo-dG Modifications

    OpenAIRE

    Mutso, Margit; Nikonov, Andrei; Pihlak, Arno; Žusinaite, Eva; Viru, Liane; Selyutina, Anastasia; Reintamm, Tõnu; Kelve, Merike; Saarma, Mart; Karelson, Mati; Merits, Andres

    2015-01-01

    The inhibitory potency of an antisense oligonucleotide depends critically on its design and the accessibility of its target site. Here, we used an RNA interference-guided approach to select antisense oligonucleotide target sites in the coding region of the highly structured hepatitis C virus (HCV) RNA genome. We modified the conventional design of an antisense oligonucleotide containing locked nucleic acid (LNA) residues at its termini (LNA/DNA gapmer) by inserting 8-oxo-2’-deoxyguanosine (8-...

  16. Development of boron concentration analysis system and techniques for testing performance of BNCT facility

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hee Dong; Kim, Chang Shuk; Byun, Soo Hyun; Lee, Jae Yun; Sun, Gwang Min; Kim, Suk Kwon [Seoul National University, (Korea)

    2000-04-01

    I. Objectives and Necessity of the Project. Development of a boron concentration analysis system used for BNCT. Development of test techniques for BNCT facility. II. Contents and Scopes of the Project. (1) Design of a boron concentration analysis system at HANARO. (2) Component machining and instruments purchase, performance test. (3) Calculation and measurement of diffracted polychromatic beam quality. (4) Test procedures for boron concentration analysis system and BNCT facility. III. Result of the Project (1) Diffracted neutron beam quality for boron concentration analysis. (neutron flux: 1.2 * 10{sup 8} n/cm{sup 2}s, Cd-ratio : 1,600) (2) Components and instruments of the boron concentration analysis system. (3) Diffracted neutron spectrum and flux. (4) Test procedures for boron concentration analysis system and BNCT facility. 69 refs., 44 figs., 14 tabs. (Author)

  17. Electrophoretic deposits of boron on duralumin plates used for measuring neutron flux

    International Nuclear Information System (INIS)

    Preparation of boron thin film deposits of around 1 mg per cm2 on duralumin plates with a diameter of 8 cm. The boron coated plates for ionization chambers were originally prepared at the CEA by pulverization of boron carbides on sodium silicates. This method is not controlling precisely enough the quantity of boron deposit. Thus, an electrophoretic method is considered for a better control of the quantity of boron deposit in the scope of using in the future boron 10 which is costly and rare. The method described by O. Flint is not satisfying enough and a similar electrophoretic process has been developed. Full description of the method is given as well as explanation of the use of dried methanol as solvent, tannin as electrolyte and magnesium chloride to avoid alumina formation. (M.P.)

  18. Cyclic formation of boron suboxide crystallites into star-shaped nanoplates

    International Nuclear Information System (INIS)

    Star-shaped boron suboxide (B6O) nanoplates were formed through a liquid-phase reaction of amorphous boron and boron oxide. The formation of the five-vertex B6O crystal is attributed to the oxygen-deficient state of B6Ox, where x < 1, which correlates to the lattice parameters. The mechanical properties of spark plasma sintered B6O show a hardness of 34.8 GPa and a fracture toughness of 4.0 MPa.m1/2. The understanding of the relationship between crystal atomic structure and crystal morphology could be employed in the design of other boron-rich compounds

  19. Considerations for boron neutron capture therapy studies

    International Nuclear Information System (INIS)

    Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps

  20. Adsorption of boron on a Mo(110) surface

    Energy Technology Data Exchange (ETDEWEB)

    Magkoev, Tamerlan T; Turiev, Anatolij M; Tsidaeva, Natal' ja I; Panteleev, Dmitrij G [Department of Physics, University of North Ossetia, Kesaev 121-83, Vladikavkaz 362020 (Russian Federation); Vladimirov, Georgij G; Rump, Gennadij A [Department of Physics, University of Saint Petersburg, Uljanovskaya 1-1, Saint Petersburg 198904 (Russian Federation)], E-mail: t_magkoev@mail.ru

    2008-12-03

    Adsorption of boron atoms in submonolayer to multilayer coverage on atomically clean Mo(110) surfaces has been studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS) and work function measurements. According to Auger results there is a layer-by-layer growth mode of the film on the substrate held at room temperature. In the submonolayer region the work function gradually increases with boron coverage until a saturation value of 5.8 eV is achieved after completion of the first monoatomic layer. The B-Mo(110) adsorbate system formed on the substrate at room temperature is not stable, dominated by a strong tendency of the boron atoms to diffuse into the bulk of the crystal. The latter is manifested by dramatic Mo(110) surface plasmon mode transformation upon boron adsorption, presumably as a result of penetration of boron atoms into the topmost substrate layer even at T = 300 K. Slight annealing up to 450 K facilitates this trend, leading to total dissolution of deposited boron atoms in the bulk of the crystal under further annealing, restoring the initial state of the Mo(110) surface after achieving a temperature of approximately 2000 K.

  1. Adsorption of boron on a Mo(110) surface

    Science.gov (United States)

    Magkoev, Tamerlan T.; Turiev, Anatolij M.; Tsidaeva, Natal'ja I.; Panteleev, Dmitrij G.; Vladimirov, Georgij G.; Rump, Gennadij A.

    2008-12-01

    Adsorption of boron atoms in submonolayer to multilayer coverage on atomically clean Mo(110) surfaces has been studied by Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), electron energy loss spectroscopy (EELS) and work function measurements. According to Auger results there is a layer-by-layer growth mode of the film on the substrate held at room temperature. In the submonolayer region the work function gradually increases with boron coverage until a saturation value of 5.8 eV is achieved after completion of the first monoatomic layer. The B-Mo(110) adsorbate system formed on the substrate at room temperature is not stable, dominated by a strong tendency of the boron atoms to diffuse into the bulk of the crystal. The latter is manifested by dramatic Mo(110) surface plasmon mode transformation upon boron adsorption, presumably as a result of penetration of boron atoms into the topmost substrate layer even at T = 300 K. Slight annealing up to 450 K facilitates this trend, leading to total dissolution of deposited boron atoms in the bulk of the crystal under further annealing, restoring the initial state of the Mo(110) surface after achieving a temperature of approximately 2000 K.

  2. The Influence of Parameters Affecting Boron Removal by Electrocoagulation Process

    KAUST Repository

    Zeboudji, B.

    2013-04-01

    Boron removal in seawater desalination presents a particular challenge. In seawater reverse osmosis (SWRO) systems boron removal at low concentration (<0.5 mg/L) is usually achieved by a second pass using brackish water RO membranes. However, this process requires chemical addition and important additional investment, operation and maintenance, and energy costs. Electrocoagulation (EC) process can be used to achieve such low boron concentration. In this work, the removal of boron from aqueous solution was carried out by EC process using aluminum and iron electrodes. Several operating parameters on the removal efficiency such as initial pH, current density, initial boron ion concentration, feed concentration, gap between electrodes, and electrode material, were investigated. In the case of bipolar electrocoagulation (BEC), an optimum removal efficiency of 96% corresponding to a final boron concentration of 0.4 mg/L was achieved at a current density of 6 mA/cm2 and pH = 8 using aluminum electrodes. The concentration of NaCl was 2,500 mg/L and the gap between the electrodes of 0.5 cm. Furthermore, a comparison between monopolar electrocoagulation (MEC) and BEC using both aluminum and iron electrodes was carried out. Results showed that the BEC process has reduced the current density applied to obtain high level of boron removal in a short reaction time compared to MEC process. The high performance of the EC showed that the process could be used to reduce boron concentration to acceptable levels at low-cost and more environmentally friendly. © 2013 Copyright Taylor and Francis Group, LLC.

  3. Quantitative analysis of proton boron fusion therapy (PBFT) in various conditions

    International Nuclear Information System (INIS)

    From the theoretical point of view, the PBFT has some strong advantages over currently existing radiotherapy methods. First, boron-based tumor targeting is required prior to performing the treatments such as boron-neutron capture therapy (BNCT). Tumor targeting should be performed before the BNCT by injecting the boronate compound. If boron is not taken up by the normal tissue, the normal tissue can be spared the irradiation by alpha particles. When boron uptake occurs in the target region, selective therapy is possible by neutron capture reaction of labeled boron particles in the target region. Likewise, when boron is distributed in the tumor region for the PBFT, the proposed method can represent a more critical discriminative therapy than either the BNCT or conventional particle therapy. In the conventional proton therapy, in order to deliver a dose to a tumor, the proton beam energy has to be adjusted along the tumor region (e.g., shape and depth). The proton therapy aims at delivering the maximal dose to the tumor by using protons only. In this study, the effectiveness of the PBFT with respect to several physical parameters was evaluated quantitatively by using Monte Carlo simulations. We confirmed that the PBFT can be used to perform critical discriminative therapy. Also, the results of our studies can be used for constructing the PFBT dose database that can be utilized in treatment planning systems (TPSs)

  4. Quantitative analysis of proton boron fusion therapy (PBFT) in various conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo-Young; Yoon, Do-Kun; Suh, Tae Suk [College of Medicine, Catholic University of Korea, Seoul (Korea, Republic of)

    2015-05-15

    From the theoretical point of view, the PBFT has some strong advantages over currently existing radiotherapy methods. First, boron-based tumor targeting is required prior to performing the treatments such as boron-neutron capture therapy (BNCT). Tumor targeting should be performed before the BNCT by injecting the boronate compound. If boron is not taken up by the normal tissue, the normal tissue can be spared the irradiation by alpha particles. When boron uptake occurs in the target region, selective therapy is possible by neutron capture reaction of labeled boron particles in the target region. Likewise, when boron is distributed in the tumor region for the PBFT, the proposed method can represent a more critical discriminative therapy than either the BNCT or conventional particle therapy. In the conventional proton therapy, in order to deliver a dose to a tumor, the proton beam energy has to be adjusted along the tumor region (e.g., shape and depth). The proton therapy aims at delivering the maximal dose to the tumor by using protons only. In this study, the effectiveness of the PBFT with respect to several physical parameters was evaluated quantitatively by using Monte Carlo simulations. We confirmed that the PBFT can be used to perform critical discriminative therapy. Also, the results of our studies can be used for constructing the PFBT dose database that can be utilized in treatment planning systems (TPSs)

  5. Boron thermal regeneration system

    International Nuclear Information System (INIS)

    An ion exchanger which allows flow in both directions along a selected flow path is described. A separator plate divides the exchanger tank into two chambers each of which has a flow conduit so that flow may enter or leave from either chamber while prohibiting the resin particles from migrating from one side of the tank to the other. This ion exchanger permits a dual-directional flow process to be practised which results in immediate changes in the boron concentration within a nuclear reactor coolant system even if the ion exchanger resins have not been completely equilibrated during a previous operation. (author)

  6. BORONIZING OF STEEL

    Directory of Open Access Journals (Sweden)

    Arzum ULUKÖY

    2006-02-01

    Full Text Available Boride layer has many advantages in comparison with traditional hardening methods. The boride layer has high hardening value and keeps it's hardeness at high temperatures, and it also shows favorible properties, such as the resistance to wear, oxidation and corrosion. The process can be applied at variety of materials, for instance steel, cast iron, cast steel, nickel and cobalt alloys and cermets. In this rewiew, boronizing process properties, boride layer on steel surfaces and specifications and the factors that effect boride layer are examined

  7. Nitrogen implantation effects on the chemical bonding and hardness of boron and boron nitride coatings

    Energy Technology Data Exchange (ETDEWEB)

    Anders, S; Felter, T; Hayes, J; Jankowski, A F; Patterson, R; Poker, D; Stamler, T

    1999-02-08

    Boron nitride (BN) coatings are deposited by the reactive sputtering of fully dense, boron (B) targets utilizing an argon-nitrogen (Ar-N{sub 2}) reactive gas mixture. Near-edge x-ray absorption fine structure analysis reveals features of chemical bonding in the B 1s photoabsorption spectrum. Hardness is measured at the film surface using nanoindentation. The BN coatings prepared at low, sputter gas pressure with substrate heating are found to have bonding characteristic of a defected hexagonal phase. The coatings are subjected to post-deposition nitrogen (N{sup +} and N{sub 2}{sup +}) implantation at different energies and current densities. The changes in film hardness attributed to the implantation can be correlated to changes observed in the B 1s NEXAFS spectra.

  8. Neutron beam monitor based on a boron-coated GEM

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian-Rong; LI Yi; SUN Zhi-Jia; LIU Ben; WANG Yan-Feng; YANG Gui-An; ZHOU Liang; XU Hong; DONG Jing; YANG Lei

    2011-01-01

    A new thermal neutron beam monitor with a Gas Electron Multiplier (GEM) is developed to meet the needs of the next generation of neutron facilities. A prototype chamber has been constructed with two 100 mm×100 mm GEM foils. Enriched boron-10 is coated on one surface of the aluminum cathode plate as the neutron convertor. 96 channel pads with an area of 8 mm×8 mm each are used for fast signal readout.In order to study the basic characteristics of a boron-coated GEM, several irradiation tests were carried out with α source 239pu and neutron source 241Am(Be). The signal induced by the neutron source has a high signal-to-noise ratio. A clear image obtained from α source 239pu is presented, which shows that the neutron beam monitor based on a boron-coated GEM has a good two-dimensional imaging ability.

  9. Dietary boron, brain function, and cognitive performance.

    OpenAIRE

    Penland, J G

    1994-01-01

    Although the trace element boron has yet to be recognized as an essential nutrient for humans, recent data from animal and human studies suggest that boron may be important for mineral metabolism and membrane function. To investigate further the functional role of boron, brain electrophysiology and cognitive performance were assessed in response to dietary manipulation of boron (approximately 0.25 versus approximately 3.25 mg boron/2000 kcal/day) in three studies with healthy older men and wo...

  10. PGNAA of human arthritic synovium for boron neutron capture synovectomy

    Energy Technology Data Exchange (ETDEWEB)

    Binello, E.; Yanch, J.C. [Massashucetts Institute of Technology, Cambridge, MA (United States); Shortkroff, S. [Brigham and Women`s Hospital, Boston, MA (United States)

    1997-12-01

    Boron neutron capture synovectomy (BNCS), is a proposed new therapy modality for the treatment of rheumatoid arthritis, an autoimmune disease afflicting the joints. The synovium, which is the membrane lining the joint, becomes inflamed and represents the target tissue for therapy. When a joint is unresponsive to drug treatment, physical removal of the synovium, termed synovectomy, becomes necessary. Existing options include surgery and radiation synovectomy. BNCS has advantages over these options in that it is noninvasive and does not require the administration of radioactive substances. Previous studies have shown that the uptake of {sup 10}B by human arthritic synovium ex vivo is high, ranging from 194 to 545 ppm with an unenriched boron compound. While tissue samples remain viable up to 1 week, ex vivo conditions do not accurately reflect those in vivo. This paper presents results from experiments assessing the washout of boron from the tissue and examines the implications for in vivo studies.

  11. RXFP1 is targeted by complement C1q Tumor Necrosis Factor-related factor 8 (CTRP8 in brain cancer

    Directory of Open Access Journals (Sweden)

    Thatchawan eThanasupawat

    2015-08-01

    Full Text Available The relaxin-like - RXFP1 ligand-receptor system has important functions in tumor growth and tissue invasion. Recently, we have identified the secreted protein, CTRP8, a member of the C1q/ Tumor Necrosis Factor-related protein (CTRP family, as a novel ligand of the relaxin receptor RXFP1 with functions in brain cancer. Here we review the role of CTRP members in cancers cells with particular emphasis on CTRP8 in glioblastoma.

  12. Simulation of swift boron clusters traversing amorphous carbon foils

    OpenAIRE

    Heredia Ávalos, Santiago; Abril Sánchez, Isabel; Denton Zanello, Cristian D.; García Molina, Rafael

    2007-01-01

    We use a simulation code to study the interaction of swift boron clusters (Bn+, n=2–6, 14) with amorphous carbon foils. We analyze different aspects of this interaction, such as the evolution of the cluster structure inside the target, the energy and angle distributions at the detector or the stopping power ratio. Our simulation code follows in detail the motion of the cluster fragments through the target and in the vacuum until reaching a detector, taking into account the following interacti...

  13. Lattice dynamics of α boron and of boron carbide

    International Nuclear Information System (INIS)

    The atomic structure and the lattice dynamics of α boron and of B4C boron carbide have been studied by Density Functional Theory (D.F.T.) and Density Functional Perturbation Theory (D.F.P.T.). The bulk moduli of the unit-cell and of the icosahedron have been investigated, and the equation of state at zero temperature has been determined. In α boron, Raman diffusion and infrared absorption have been studied under pressure, and the theoretical and experimental Grueneisen coefficients have been compared. In boron carbide, inspection of the theoretical and experimental vibrational spectra has led to the determination of the atomic structure of B4C. Finally, the effects of isotopic disorder have been modeled by an exact method beyond the mean-field approximation, and the effects onto the Raman lines has been investigated. The method has been applied to isotopic alloys of diamond and germanium. (author)

  14. A windowless hydrogen gas target for the measurement of 7Be(p, γ)8B with the recoil separator ERNA

    International Nuclear Information System (INIS)

    A new measurement of the cross section of 7Be(p, γ)8B will be done in inverted kinematics with the recoil separator ERNA at the CIRCE laboratory in Caserta, Italy. The 8B recoils will be produced in a windowless hydrogen gas target. We report here on the construction and characterization of the gas cell. In detail we describe measurements for target density, the profile determination via the 7Li(p, p')7Li* reaction as well as the role and performance of a gaseous post-stripper. (orig.)

  15. Mitochondrial-targeted DNA repair enzyme 8-oxoguanine DNA glycosylase 1 protects against ventilator-induced lung injury in intact mice

    OpenAIRE

    Hashizume, Masahiro; Mouner, Marc; Joshua M. Chouteau; Gorodnya, Olena M.; Ruchko, Mykhaylo V.; Potter, Barry J.; Wilson, Glenn L.; Gillespie, Mark N.; Parker, James C.

    2012-01-01

    This study tested the hypothesis that oxidative mitochondrial-targeted DNA (mtDNA) damage triggered ventilator-induced lung injury (VILI). Control mice and mice infused with a fusion protein targeting the DNA repair enzyme, 8-oxoguanine-DNA glycosylase 1 (OGG1) to mitochondria were mechanically ventilated with a range of peak inflation pressures (PIP) for specified durations. In minimal VILI (1 h at 40 cmH2O PIP), lung total extravascular albumin space increased 2.8-fold even though neither l...

  16. New Small LWR Core Designs using Particle Burnable Poisons for Low Boron Concentration

    International Nuclear Information System (INIS)

    The soluble boron has two major important roles in commercial PWR operations : 1) the control of the long-term reactivity to maintain criticality under normal operation, and 2) the shutdown of the reactor under accidents. However, the removal of the soluble boron gives several advantages in SMRs (Small Modular Reactor). These advantages resulted from the elimination of soluble boron include the significant simplification of nuclear power plant through the removal of pipes, pumps, and purification systems. Also, the use of soluble boron mitigates corrosion problems on the primary coolant loop. Furthermore, the soluble boron-free operation can remove an inadvertent boron dilution accident (BDA) which can lead to a significant insertion of positive reactivity. From the viewpoint of core physics, the removal of soluble boron or reduction of soluble boron concentration makes the moderator temperature coefficient (MTC) more negative. From the core design studies using new fuel assemblies, it is shown that the cores have very low critical soluble boron concentrations less than 500ppm, low peaking factors within the design targets, strong negative MTCs over cycles, and large enough shutdown margins both at BOC and EOC. However, the present cores have relatively low average discharge burnups of ∼ 30MWD/kg leading to low fuel economy because the cores use lots of non-fuel burnable poison rods to achieve very low critical boron concentrations. So, in the future, we will perform the trade-off study between the fuel discharge burnup and the boron concentrations by changing fuel assembly design and the core loading pattern

  17. A new and effective approach to boron removal by using novel boron-specific fungi isolated from boron mining wastewater.

    Science.gov (United States)

    Taştan, Burcu Ertit; Çakir, Dilara Nur; Dönmez, Gönül

    2016-01-01

    Boron-resistant fungi were isolated from the wastewater of a boron mine in Turkey. Boron removal efficiencies of Penicillium crustosum and Rhodotorula mucilaginosa were detected in different media compositions. Minimal Salt Medium (MSM) and two different waste media containing molasses (WM-1) or whey + molasses (WM-2) were tested to make this process cost effective when scaled up. Both isolates achieved high boron removal yields at the highest boron concentrations tested in MSM and WM-1. The maximum boron removal yield by P. crustosum was 45.68% at 33.95 mg l(-1) initial boron concentration in MSM, and was 38.97% at 42.76 mg l(-1) boron for R. mucilaginosa, which seemed to offer an economically feasible method of removing boron from the effluents. PMID:26877036

  18. Quantification of corrosion resistance of a new-class of criticality control materials: thermal-spray coatings of high-boron iron-based amorphous metals - Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J C; Choi, J S; Shaw, C K; Rebak, R; Day, S D; Lian, T; Hailey, P; Payer, J H; Branagan, D J; Aprigliano, L F

    2007-03-28

    An iron-based amorphous metal, Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} (SAM2X5), with very good corrosion resistance was developed. This material was produced as a melt-spun ribbon, as well as gas atomized powder and a thermal-spray coating. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation. The high boron content of this particular amorphous metal made it an effective neutron absorber, and suitable for criticality control applications. Earlier studies have shown that ingots and melt-spun ribbons of these materials have good passive film stability in these environments. Thermal spray coatings of these materials have now been produced, and have undergone a variety of corrosion testing, including both atmospheric and long-term immersion testing. The modes and rates of corrosion have been determined in the various environments, and are reported here.

  19. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Quintas, Ignacio; Oujja, Mohamed; Sanz, Mikel; Benitez-Cañete, Antonio [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Chater, Richard J. [Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Cañamares, Maria Vega [Instituto de Estructura de la Materia, CSIC, Serrano 119, 28006 Madrid (Spain); Marco, José F. [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Castillejo, Marta, E-mail: marta.castllejo@iqfr.csic.es [Instituto de Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2015-02-15

    Highlights: • Micrometric rods obtained by ns pulsed laser deposition of boron carbide at 1064 and 266 nm. • At 1064 nm microrods display crystalline polyhedral shape with sharp edges and flat sides. • Microrods consist of a mixture of boron, boron oxide, boron carbide and aliphatic hydrocarbons. - Abstract: Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved.

  20. Micrometric rods grown by nanosecond pulsed laser deposition of boron carbide

    International Nuclear Information System (INIS)

    Highlights: • Micrometric rods obtained by ns pulsed laser deposition of boron carbide at 1064 and 266 nm. • At 1064 nm microrods display crystalline polyhedral shape with sharp edges and flat sides. • Microrods consist of a mixture of boron, boron oxide, boron carbide and aliphatic hydrocarbons. - Abstract: Micrometric size rods have been fabricated via pulsed laser deposition in vacuum from boron carbide targets using nanosecond pulses of 1064 and 266 nm and room temperature Si (1 0 0) substrates. Morphological, structural and chemical characterization of the microrods was made by applying scanning electron microscopy, focussed ion beam microscopy coupled to secondary ion mass spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and micro-Raman spectroscopy. Ablation at 1064 nm favours the formation of microrods with high aspect ratio, sharp edges and pyramidal tips, typically 10 μm long with a cross section of around 2 μm × 2 μm. Differently, at 266 nm the microrods are of smaller size and present a more globular aspect. The analyses of the microrods provide information about their crystalline nature and composition, based on a mixture which includes boron, boron oxide and boron carbide, and allows discussion of the wavelength dependent growth mechanisms involved

  1. Development of boronated tumor-seeking materials for application in neutron capture therapy of cancer

    International Nuclear Information System (INIS)

    Full text: At the present time the main field of application of boron compounds in medicine is Boron Neutron Capture Therapy (BNCT) of cancer. In this presentation the main principles of BNCT and main types of polyhedral boron compounds used for BNCT will be shown. The successful treatment of tumors by BNCT requires selective delivery of the boron moiety into the tumor cells. One of ways to solve this problem is attachment of boron fragment to different tumor-specific targeting molecules. Literature and our recent results on the preparation of novel boronated amino acids, carboranecarboxylic acids, a design of different conjugates of polyhedral boron compounds with tumor-seeking molecules, like porphyrins, phthalocyanines, nucleosides, carbohydrates, and lipids will be presented. Conjugates of natural porphyrins and phthalocyanines with carborane, closo-dodecaborate and cobalt bis(dicarbollide) were synthesized. The combination of these two fragments in one molecule makes these compounds potentially useful for both fluorescence diagnostics (FD) and BNCT of tumours. Boronated nucleosides are considered to be potential BNCT candidates because they can accumulate in the tumor cells. Thus, we have succeeded in preparation of the very first conjugates of closo-dodecaborate anion with one canonic nucleoside (thymidine)

  2. Boron neutron capture therapy for recurrent head and neck malignancies

    International Nuclear Information System (INIS)

    To avoid severe impairment of oro-facial structures and functions, it is necessary to explore new treatments for recurrent head and neck malignancies (HNM). Boron neutron capture therapy (BNCT) is tumor-cell targeted radiotherapy that has significant superiority over conventional radiotherapies in principle. So far for 4 years and 3 months, we have treated with 37 times of BNCT for 21 patients (14 squamous cell carcinomas (SCC), 4 salivary gland carcinomas and 3 sarcomas) with a recurrent and far advanced HNM since 2001. Results are (1) 10B concentration of tumor/normal tissue ratio (T/N ratio) of FBPA-PET studies were SCC: 1.8-5.7, sarcoma: 2.5-4.0, parotid tumor: 2.5-3.7. (2) Therapeutic effects were CR: 6cases, PR: 11cases, PD: 3cases NE (not evaluated): 1case. Response rate was 81%. (3) Improvement of QOL such as a relief of severe pain, bleeding, and exudates at the local lesion, improvement of PS, disappearance of ulceration, covered with normal skin and preserved oral and maxillofacial functions and tissues. (4) Survival periods after BNCT were 1-51 months (mean: 9.8 months). 4-year survival rate was 39% by Kaplan-Meier analysis. (5) A few adverse-effects such as transient mucositis, alopecia were recognized. These results indicate that BNCT represents a new and promising treatment approach for advanced HNM. (author)

  3. Structural characterization of electrodeposited boron

    Indian Academy of Sciences (India)

    Ashish Jain; C Ghosh; T R Ravindran; S Anthonysamy; R Divakar; E Mohandas; G S Gupta

    2013-12-01

    Structural characterization of electrodeposited boron was carried out by using transmission electron microscopy and Raman spectroscopy. Electron diffraction and phase contrast imaging were carried out by using transmission electron microscopy. Phase identification was done based on the analysis of electron diffraction patterns and the power spectrum calculated from the lattice images from thin regions of the sample. Raman spectroscopic examination was carried out to study the nature of bonding and the allotropic form of boron obtained after electrodeposition. The results obtained from transmission electron microscopy showed the presence of nanocrystallites embedded in an amorphous mass of boron. Raman microscopic studies showed that amorphous boron could be converted to its crystalline form at high temperatures.

  4. Towards an understanding of deep boron: study of type IIb blue diamonds

    Science.gov (United States)

    Gaillou, E.; Rost, D.; Post, J. E.; Butler, J. E.

    2012-12-01

    Boron concentration and isotopic signature are known as a tracer of recycled crustal material from subduction zones inside the Earth's mantle. Thus far, the focus has been on analyzing boron in volcanic rocks and olivine inclusions. However, these materials always experience some degree of late processing on their way to the surface (alteration, crystallization, change in structure, etc.). As of now, the boron content and isotopic ratio of the mantle end-member is only assumed through mass balance calculations (Chaussidon & Marty, 1995). Diamonds, on the other hand, would be a more ideal material to analyze for boron, as it does not undergo significant processing while on its way to the surface. Boron-containing diamonds are well known but extremely rare; they are referred as type IIb diamonds. They are highly valuable in the gem market, as the presence of boron in the diamond structure gives rise to the blue color, such as in the Hope diamond. Only a few boron analyses have been undertaken on type IIb natural diamonds, however, it is generally accepted that their boron concentration is ~1 ppm or lower. The combination of rarity, high value, and low boron content are the most likely reasons why geologists have not yet performed boron analyses on blue diamonds. This study used various spectroscopic methods and time-of-fight (ToF-) SIMS, which are non- or nearly non-destructive techniques, to characterize and analyze for boron in natural type IIb blue diamonds, including the well-known Hope diamond. Results obtained by Fourier Transform Infrared (FTIR) and phosphorescence spectroscopies on 103 diamonds will be presented and compared to some analyses of boron contents measured using ToF-SIMS. ToF-SIMS analyses gave spot (50 x 50 μm x few nm deep) boron concentrations as high as 8.4 ± 1.1 (atomic) ppm for the Hope diamond to less than 0.08 ppm in other blue diamonds, with an overall average value of ~1 ppm. ToF-SIMS analyses revealed strong zoning of boron in some

  5. Mfge8 diminishes the severity of tissue fibrosis in mice by binding and targeting collagen for uptake by macrophages

    OpenAIRE

    Atabai, Kamran; Jame, Sina; Azhar, Nabil; Kuo, Alex; Lam, Michael; McKleroy, William; DeHart, Greg; Rahman, Salman; Xia, Dee Dee; Melton, Andrew C.; Wolters, Paul; Emson, Claire L.; Turner, Scott M.; Werb, Zena; Sheppard, Dean

    2009-01-01

    Milk fat globule epidermal growth factor 8 (Mfge8) is a soluble glycoprotein known to regulate inflammation and immunity by mediating apoptotic cell clearance. Since fibrosis can occur as a result of exaggerated apoptosis and inflammation, we set out to investigate the hypothesis that Mfge8 might negatively regulate tissue fibrosis. We report here that Mfge8 does decrease the severity of tissue fibrosis in a mouse model of pulmonary fibrosis; however, it does so not through effects on inflamm...

  6. Characterization of the nuclear matrix targeting sequence (NMTS) of the BPV1 E8/E2 protein--the shortest known NMTS.

    Science.gov (United States)

    Sankovski, Eve; Karro, Kristiina; Sepp, Mari; Kurg, Reet; Ustav, Mart; Abroi, Aare

    2015-01-01

    Technological advantages in sequencing and proteomics have revealed the remarkable diversity of alternative protein isoforms. Typically, the localization and functions of these isoforms are unknown and cannot be predicted. Also the localization signals leading to particular subnuclear compartments have not been identified and thus, predicting alternative functions due to alternative subnuclear localization is limited only to very few subnuclear compartments. Knowledge of the localization and function of alternative protein isoforms allows for a greater understanding of cellular complexity. In this article, we characterize a short and well-defined signal targeting the bovine papillomavirus type 1 E8/E2 protein to the nuclear matrix. The targeting signal comprises the peptide coded by E8 ORF, which is spliced together with part of the E2 ORF to generate the E8/E2 mRNA. Localization to the nuclear matrix correlates well with the transcription repression activities of E8/E2; a single point mutation directs the E8/E2 protein into the nucleoplasm, and transcription repression activity is lost. Our data prove that adding as few as ˜10 amino acids by alternative transcription/alternative splicing drastically alters the function and subnuclear localization of proteins. To our knowledge, E8 is the shortest known nuclear matrix targeting signal. PMID:26218798

  7. Characterization of the nuclear matrix targeting sequence (NMTS) of the BPV1 E8/E2 protein — the shortest known NMTS

    Science.gov (United States)

    Sankovski, Eve; Karro, Kristiina; Sepp, Mari; Kurg, Reet; Ustav, Mart; Abroi, Aare

    2015-01-01

    Technological advantages in sequencing and proteomics have revealed the remarkable diversity of alternative protein isoforms. Typically, the localization and functions of these isoforms are unknown and cannot be predicted. Also the localization signals leading to particular subnuclear compartments have not been identified and thus, predicting alternative functions due to alternative subnuclear localization is limited only to very few subnuclear compartments. Knowledge of the localization and function of alternative protein isoforms allows for a greater understanding of cellular complexity. In this article, we characterize a short and well-defined signal targeting the bovine papillomavirus type 1 E8/E2 protein to the nuclear matrix. The targeting signal comprises the peptide coded by E8 ORF, which is spliced together with part of the E2 ORF to generate the E8/E2 mRNA. Localization to the nuclear matrix correlates well with the transcription repression activities of E8/E2; a single point mutation directs the E8/E2 protein into the nucleoplasm, and transcription repression activity is lost. Our data prove that adding as few as ˜10 amino acids by alternative transcription/alternative splicing drastically alters the function and subnuclear localization of proteins. To our knowledge, E8 is the shortest known nuclear matrix targeting signal. PMID:26218798

  8. Boron diffusion in silicon devices

    Science.gov (United States)

    Rohatgi, Ajeet; Kim, Dong Seop; Nakayashiki, Kenta; Rounsaville, Brian

    2010-09-07

    Disclosed are various embodiments that include a process, an arrangement, and an apparatus for boron diffusion in a wafer. In one representative embodiment, a process is provided in which a boric oxide solution is applied to a surface of the wafer. Thereafter, the wafer is subjected to a fast heat ramp-up associated with a first heating cycle that results in a release of an amount of boron for diffusion into the wafer.

  9. Boron-containing neutron shielding building ceramics

    International Nuclear Information System (INIS)

    The data are presented on the composition of raw materials as well as on the properties and chemical composition of finished products of ceramics intended for neutron shielding. It is shown that 0.8 % content of B2O3 in bricks of ceramic mass proposed halves neutron radiation from the source of 106 neutr·s-1 close rate compared to bricks of boron free ceramic mass. Results of tests on water absorption and compression strength make it possible to recommend new ceramics to be used as tiles and facade building materials

  10. Tumor cell killing effect of boronated dipeptide. Boromethylglycylphenylalanine on boron neutron capture therapy for malignant brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Takagaki, Masao; Ono, Koji; Masunaga, Shinichiro; Kinashi, Yuko; Kobayashi, Toru [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Oda, Yoshifumi; Kikuchi, Haruhiko; Spielvogel, B.F.

    1994-03-01

    The killing effect of Boron Neutron Capture Therapy; BNCT, is dependant on the boron concentration ratio of tumor to normal brain (T/N ratio), and also that of tumor to blood (T/B ratio). The clinical boron carrier of boro-captate (BSH) showed the large T/N ratio of ca. 8, however the T/B ratio was around 1, which indicated nonselective accumulation into tumor. Indeed high boron concentration of blood restrict the neutron irradiation dose in order to circumvent the normal endothelial damage, especially in the case of deeply seated tumor. Phenylalanine analogue of para borono-phenylalanine (BPA) is an effective boron carrier on BNCT for malignant melanoma. For the BNCT on brain tumors, however, BPA concentration in normal brain was reported to be intolerably high. In order to improve the T/N ratio of BPA in brain, therefore, a dipeptide of boromethylglycylphenylalanine (BMGP) was synthesized deriving from trimethylglycine conjugated with BPA. It is expected to be selectively accumulated into tumor with little uptake into normal brain. Because a dipeptide might not pass through the normal blood brain barrier (BBB). Its killing effect on cultured glioma cell, T98G, and its distribution in rat brain bearing 9L glioma have been investigated in this paper. The BNCT effect of BMGP on cultured cells was nearly triple in comparison with DL-BPA. The neutron dose yielding 1% survival ratio were 7x10{sup 12}nvt for BMGP and 2x10{sup 13}nvt for BPA respectively on BNCT after boron loading for 16 hrs in the same B-10 concentration of 20ppm. Quantitative study of boron concentration via the {alpha}-auto radiography and the prompt gamma ray assay on 9L brain tumor rats revealed that T/N ratio and T/B ratio are 12.0 and 3.0 respectively. Those values are excellent for BNCT use. (author).

  11. Glycan-modified liposomes boost CD4+ and CD8+ T-cell responses by targeting DC-SIGN on dendritic cells

    NARCIS (Netherlands)

    W.W.J. Unger; A.J. van Beelen; S.C. Bruijns; M. Joshi; C.M. Fehres; L. van Bloois; M.I. Verstege; M. Ambrosini; H. Kalay; K. Nazmi; J.G. Bolscher; E. Hooiberg; T.D. de Gruijl; G. Storm; Y. van Kooyk

    2012-01-01

    Cancer immunotherapy requires potent tumor-specific CD8+ and CD4+ T-cell responses, initiated by dendritic cells (DCs). Tumor antigens can be specifically targeted to DCs in vivo by exploiting their expression of C-type lectin receptors (CLR), which bind carbohydrate structures on antigens, resultin

  12. The preparation and characterization of boron-containing phenolic fibers

    International Nuclear Information System (INIS)

    The boron-containing phenolic fibers were prepared by melt-spinning a mixture of novolak resin and boron acid followed by curing the filaments with formaldehyde solution in the presence of an acid catalyst. The resulting fibers were heat-treated in N2 at elevated temperatures. The results show that the addition of 1.0 wt% boron acid in the precursor resin can greatly increase thermal stability, mechanical strength and flame resistance of the resultant fibers. In comparison the boron-containing phenolic fibers with the pure phenolic fibers, the weight loss of the boron-containing phenolic fibers (BPF-1.0), heat-treated at 240 deg. C for 2 h, decreases from 60.5 to 39.1% in N2, from 32.8 to 14.1% in air. Whereas, the limited oxygen index increases from 32.5 to 37.2%; the tensile strength increases from 129.3 to 163.4 MPa.

  13. New Ground-State Crystal Structure of Elemental Boron.

    Science.gov (United States)

    An, Qi; Reddy, K Madhav; Xie, Kelvin Y; Hemker, Kevin J; Goddard, William A

    2016-08-19

    Elemental boron exhibits many polymorphs in nature based mostly on an icosahedral shell motif, involving stabilization of 13 strong multicenter intraicosahedral bonds. It is commonly accepted that the most thermodynamic stable structure of elemental boron at atmospheric pressure is the β rhombohedral boron (β-B). Surprisingly, using high-resolution transmission electron microscopy, we found that pure boron powder contains grains of two different types, the previously identified β-B containing a number of randomly spaced twins and what appears to be a fully transformed twinlike structure. This fully transformed structure, denoted here as τ-B, is based on the Cmcm orthorhombic space group. Quantum mechanics predicts that the newly identified τ-B structure is 13.8  meV/B more stable than β-B. The τ-B structure allows 6% more charge transfer from B_{57} units to nearby B_{12} units, making the net charge 6% closer to the ideal expected from Wade's rules. Thus, we predict the τ-B structure to be the ground state structure for elemental boron at atmospheric pressure. PMID:27588864

  14. Boron Fullerenes: A First-Principles Study

    Directory of Open Access Journals (Sweden)

    Gonzalez Szwacki Nevill

    2007-01-01

    Full Text Available AbstractA family of unusually stable boron cages was identified and examined using first-principles local-density functional method. The structure of the fullerenes is similar to that of the B12icosahedron and consists of six crossing double-rings. The energetically most stable fullerene is made up of 180 boron atoms. A connection between the fullerene family and its precursors, boron sheets, is made. We show that the most stable boron sheets are not necessarily precursors of very stable boron cages. Our finding is a step forward in the understanding of the structure of the recently produced boron nanotubes.

  15. Solvent extraction of boron complex with H-resorcinol and diphenylguanidine

    International Nuclear Information System (INIS)

    Conditions have been studied for the formation of a complex of boron with H-resorcinol (2.4-dihydroxybenzene-azo-8-hydroxynaphthalene-3.6-disulphoric acid) and diphenylguanidine (DPG) which is extracted into higher alcohols (pentanols). The component ratio in the complex is B:HR:DPG=1:1:2. The reaction between boron and H-resorcinol is significantly accelerated in the presence of DPG that makes it possible to apply the reaction to extraction-photometric determination of boron. The infrared studies have confirmed the quinone-hydrazone form of H-resorcinol in the complex with boron. The method allows to determine 1x10-4 - 5x10-2% of boron

  16. Deposition of hexagonal boron nitride thin films on silver nanoparticle substrates and surface enhanced infrared absorption

    International Nuclear Information System (INIS)

    Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency (RF) magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  17. Electron-impact excitation and ionization of atomic boron at low and intermediate energies

    Science.gov (United States)

    Wang, Kedong; Zatsarinny, Oleg; Bartschat, Klaus

    2016-05-01

    We present a comprehensive study of electron collisions with boron atoms by using the B -spline R -matrix method for electron energies ranging from threshold to 100 eV. Elastic, excitation, and ionization cross sections were obtained for all transitions between the lowest 11 states of boron. A multiconfiguration Hartree-Fock method with nonorthogonal term-dependent orbitals was employed to generate accurate wave functions for the target states. Close-coupling expansions including 13, 51, and 999 physical and pseudo-target states of boron were used to check the sensitivity of the results to changes in the theoretical model. The cross-section dataset obtained from the large-scale calculations is expected to be sufficiently accurate and comprehensive for most current modeling applications involving neutral boron.

  18. 2.4. The kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit

    International Nuclear Information System (INIS)

    Present article is devoted to kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit. The experimental data of dependence of hydrochloric-acid decomposition of calcined boron raw material for boron oxide extraction on temperature (20-80 deg C) and process duration (15-60 min) were considered. It was defined that at temperature increasing the boron oxide extraction from borosilicate raw material increases from 24.1 till 86.8%. The constants of decomposition rate of boron raw material were calculated.

  19. For boron neutron capture therapy,synthesizing boron-polymer compounds and testing in laboratory conditions

    International Nuclear Information System (INIS)

    The aim of this project is to establish a focus point at Turkish Atomic Energy Authority (TAEA) in the field of Boron Neutron Capture Therapy which is a binary radiotherapy method for brain tumours. Moreover in the scope of the project, a new alternative of 10B-carrier compounds will be synthesized, the neutron source will be determined and the infrastructure to start the clinical trials of BNCT in our country will be established. BNCT is a binary radiotherapy method and the successful of this method is depend on the synthesized boron compounds which have the selective targeting property with tumour cells and neutron optimization. The water-soluble polymer based boron compounds having biochemical and physiological properties will be synthesized and cell culture experiment will be done. In addition, after the neutron source is set up in our country, the infrastructure studies will be started in order to start the clinical trials of BNCT. In this project, there are three different groups as boron compounds, neutron physics and medical group. Neutron physics group is starting the calculations of neutron beam parameters using in BNCT application. But, medical group has no active studies yet. Boron compounds group has been carried out two different experimental studies. In the first experimental study, functional groups have been bound to boron containing polymers to enhance the selectively targeting property and characterized by various analysis methods. Later, cell culture experiment will be done. The first study has been carried out with Hacettepe University. Up to present, completed studies are listed as: -Maleic anhydride oligomer was synthesized and then 2-aminoethyl diphenyl borate (2-AEPB) and monomethoxy poly(ethylene glycol) (PEG) was bound to this oligomer, respectively. Thus, [MAH]n-g1-2-AEPB-g2-PEG was synthesized. -2-AEPB compound were bound to poly(acrylic acid) polymer at different three mole ratio.Then, the selected Poli(Ac)-g1-2-AEPB polymer was

  20. Dynamic polarization and relaxation of protons in 1,6-hexanediol and 1,8-octanediol a feasibility study for a frozen spin polarized target

    CERN Document Server

    Borghini, M; Udo, Fred; Weymuth, P

    1972-01-01

    Results are given of an experiment to test 1,6-hexanediol and 1,8- octanediol for their suitability as materials for polarized proton targets. The samples are doped with 15% Cr/sup V/-glycol complexes. Polarization results are reported at temperatures between 0.4 K and 1.0 K. Relaxation times in different magnetic fields are measured for hexanediol down to 270 mK, for octanediol down to 54 mK. Conclusions are drawn for the parameters of a frozen spin target. (28 refs).

  1. Wettability of boron carbide

    International Nuclear Information System (INIS)

    The wettability of boron carbide has been examined by means of the sessile drop method, using the following candidate alloys: (96wt%AG-4wt%Ti), (Ag-26.5wt%Cu-3wt%Ti), (Sn-10wt%Ag-4wt%Ti), Sn(99.95wt%) and Al(99.99wt%). The results show that B4C is completely wetted by the Ag-based alloys. Sn-10wt%Ag-4wt%Ti alloy and pure Al partly wet the B4C surface, while pure Sn does not wet B4C at all. For all the alloys used, except pure Sn, a reaction layer was observed at the interface between the ceramic part and the metal drop. Although the spreading kinetics of the Al-drop was much slower compared with the Ti-containing alloys, the reaction rate was considerably higher in the former case. This suggests that aluminium is an attractive candidate material for brazing of B4C. Formation of the low melting B2O3 at the B4C surface may cause oxidation of the filler metal during joining, which, in turn, leads to a low bond strength

  2. Sp5 and Sp8 recruit β-catenin and Tcf1-Lef1 to select enhancers to activate Wnt target gene transcription.

    Science.gov (United States)

    Kennedy, Mark W; Chalamalasetty, Ravindra B; Thomas, Sara; Garriock, Robert J; Jailwala, Parthav; Yamaguchi, Terry P

    2016-03-29

    The ancient, highly conserved, Wnt signaling pathway regulates cell fate in all metazoans. We have previously shown that combined null mutations of the specificity protein (Sp) 1/Klf-like zinc-finger transcription factorsSp5andSp8(i.e.,Sp5/8) result in an embryonic phenotype identical to that observed when core components of the Wnt/β-catenin pathway are mutated; however, their role in Wnt signal transduction is unknown. Here, we show in mouse embryos and differentiating embryonic stem cells that Sp5/8 are gene-specific transcriptional coactivators in the Wnt/β-catenin pathway. Sp5/8 bind directly to GC boxes in Wnt target gene enhancers and to adjacent, or distally positioned, chromatin-bound T-cell factor (Tcf) 1/lymphoid enhancer factor (Lef) 1 to facilitate recruitment of β-catenin to target gene enhancers. BecauseSp5is itself directly activated by Wnt signals, we propose that Sp5 is a Wnt/β-catenin pathway-specific transcripton factor that functions in a feed-forward loop to robustly activate select Wnt target genes. PMID:26969725

  3. DNA Vaccines Encoding Antigen Targeted to MHC Class II Induce Influenza-Specific CD8(+) T Cell Responses, Enabling Faster Resolution of Influenza Disease.

    Science.gov (United States)

    Lambert, Laura; Kinnear, Ekaterina; McDonald, Jacqueline U; Grodeland, Gunnveig; Bogen, Bjarne; Stubsrud, Elisabeth; Lindeberg, Mona M; Fredriksen, Agnete Brunsvik; Tregoning, John S

    2016-01-01

    Current influenza vaccines are effective but imperfect, failing to cover against emerging strains of virus and requiring seasonal administration to protect against new strains. A key step to improving influenza vaccines is to improve our understanding of vaccine-induced protection. While it is clear that antibodies play a protective role, vaccine-induced CD8(+) T cells can improve protection. To further explore the role of CD8(+) T cells, we used a DNA vaccine that encodes antigen dimerized to an immune cell targeting module. Immunizing CB6F1 mice with the DNA vaccine in a heterologous prime-boost regime with the seasonal protein vaccine improved the resolution of influenza disease compared with protein alone. This improved disease resolution was dependent on CD8(+) T cells. However, DNA vaccine regimes that induced CD8(+) T cells alone were not protective and did not boost the protection provided by protein. The MHC-targeting module used was an anti-I-E(d) single chain antibody specific to the BALB/c strain of mice. To test the role of MHC targeting, we compared the response between BALB/c, C57BL/6 mice, and an F1 cross of the two strains (CB6F1). BALB/c mice were protected, C57BL/6 were not, and the F1 had an intermediate phenotype; showing that the targeting of antigen is important in the response. Based on these findings, and in agreement with other studies using different vaccines, we conclude that, in addition to antibody, inducing a protective CD8 response is important in future influenza vaccines. PMID:27602032

  4. Thermal conductivity of boron carbide-boron nitride composites

    International Nuclear Information System (INIS)

    This paper reports that because of their preferred orientation, the addition of boron nitride dispersions to hot-pressed boron carbide was found to result in a considerable degree of anisotropy in thermal conductivity of the resulting composite, indicated by an increase in the thermal conductivity perpendicular to the hot-pressing direction by as much as a factor of 3 at the highest boron nitride volume fractions of this study, and a decrease in the thermal conductivity parallel to the hot-pressing direction by as much as a factor of 2. The composite data were found to be below the values expected from composite theory, which may represent indirect evidence for the existence of an interfacial thermal barrier

  5. Proceedings of workshop on 'boron chemistry and boron neutron capture therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the 5th Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 22 in 1993. The solubility of the boron carrier play an important role in the BNCT. New water-soluble p-boronophenylalanine derivatives are synthesized and their biological activities are investigated (Chap. 2 and 3). Some chemical problems on the BNCT were discussed, and the complex formation reaction of hydroxylboryl compounds were studied by the paper electrophoresis (Chap. 4). The results of the medical investigation on the BNCT using BSH compounds are shown in Chap. 5. Syntheses of o- and m-boronophenylalanine were done and their optical resolution was tried (Chap. 6). The complex formation reaction of p-boronophenylalanine (BPA) with L-DOPA and the oxidation reaction of the analogs are found in Chap. 7. The pka of BPA were determined by the isotachophoresis (Chap. 8). The chemical nature of dihydroxyboryl compounds were investigated by an infrared spectroscopy and electrophoresis (Chap. 9). New synthetic methods of BPA and p-boronophenylserine using ester of isocyanoacetic acid are described in Chap. 10. The induction of chromosomal aberations by neutron capture reaction are discussed from a point of the biological view. The a of the presented papers are indexed individually. (J.P.N.)

  6. The boron trifluoride nitromethane adduct

    Science.gov (United States)

    Ownby, P. Darrell

    2004-02-01

    The separation of the boron isotopes using boron trifluoride·organic-donor, Lewis acid·base adducts is an essential first step in preparing 10B enriched and depleted crystalline solids so vital to nuclear studies and reactor applications such as enriched MgB 2, boron carbide, ZrB 2, HfB 2, aluminum boron alloys, and depleted silicon circuits for radiation hardening and neutron diffraction crystal structure studies. The appearance of this new adduct with such superior properties demands attention in the continuing search for more effective and efficient means of separation. An evaluation of the boron trifluoride nitromethane adduct, its thermodynamic and physical properties related to large-scale isotopic separation is presented. Its remarkably high separation factor was confirmed to be higher than the expected theoretical value. However, the reportedly high acid/donor ratio was proven to be an order of magnitude lower. On-going research is determining the crystal structure of deuterated and 11B enriched 11BF 3·CD 3NO 2 by X-ray and neutron diffraction.

  7. RXFP1 is Targeted by Complement C1q Tumor Necrosis Factor-Related Factor 8 in Brain Cancer

    OpenAIRE

    Thanasupawat, Thatchawan; Glogowska, Aleksandra; Burg, Maxwell; Wong, G. William; Hoang-Vu, Cuong; Hombach-Klonisch, Sabine; Klonisch, Thomas

    2015-01-01

    The relaxin-like RXFP1 ligand–receptor system has important functions in tumor growth and tissue invasion. Recently, we have identified the secreted protein, CTRP8, a member of the C1q/tumor necrosis factor-related protein (CTRP) family, as a novel ligand of the relaxin receptor, RXFP1, with functions in brain cancer. Here, we review the role of CTRP members in cancers cells with particular emphasis on CTRP8 in glioblastoma.

  8. RXFP1 is Targeted by Complement C1q Tumor Necrosis Factor-Related Factor 8 in Brain Cancer.

    Science.gov (United States)

    Thanasupawat, Thatchawan; Glogowska, Aleksandra; Burg, Maxwell; Wong, G William; Hoang-Vu, Cuong; Hombach-Klonisch, Sabine; Klonisch, Thomas

    2015-01-01

    The relaxin-like RXFP1 ligand-receptor system has important functions in tumor growth and tissue invasion. Recently, we have identified the secreted protein, CTRP8, a member of the C1q/tumor necrosis factor-related protein (CTRP) family, as a novel ligand of the relaxin receptor, RXFP1, with functions in brain cancer. Here, we review the role of CTRP members in cancers cells with particular emphasis on CTRP8 in glioblastoma. PMID:26322020

  9. CYP2C8 Is a Novel Target of Peroxisome Proliferator-Activated Receptor α in Human Liver.

    Science.gov (United States)

    Makia, Ngome L; Goldstein, Joyce A

    2016-01-01

    Human cytochrome P450 (CYP) 2C enzymes metabolize ∼30% of clinically prescribed drugs and various environmental chemicals. CYP2C8, an important member of this subfamily, metabolizes the anticancer drug paclitaxel, certain antidiabetic drugs, and endogenous substrates, including arachidonic acid, to physiologically active epoxyeicosatrienoic acids. Previous studies from our laboratory showed that microRNA 107 (miR107) and microRNA 103 downregulate CYP2C8 post-transcriptionally. miR107 is located in intron 5 of the pantothenate kinase 1 (PANK1) gene. p53 has been reported to coregulate the induction of PANK1 and miR107. Here, we examine the possible downregulation of CYP2C8 by drugs capable of inducing miR107. Hypolipidemic drugs, such as bezafibrate, known activators of the peroxisome proliferator-activated receptor α (PPARα), induce both the PANK1 gene and miR107 (∼2.5-fold) in primary human hepatocytes. Surprisingly, CYP2C8 mRNA and protein levels were induced by bezafibrate. CYP2C8 promoter activity was increased by ectopic expression of PPARα in HepG2 cells, with a further increase after bezafibrate (∼18-fold), 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthio acetic acid (∼10-fold) treatment, or the antidiabetic drug rosiglitazone, all known PPAR activators. Promoter sequence analyses, deletion studies, mutagenesis studies, and electrophoretic mobility shift assays identified a PPARα response element located at position -2109 base pair relative to the translation start site of CYP2C8. Chromatin immunopreciptation assay analysis confirmed recruitment of PPARα to this PPARα response element after bezafibrate treatment of human hepatocytes. Thus, we show for the first time that CYP2C8 is transcriptionally regulated by PPARα, suggesting the potential for drug-drug interactions due to upregulation of CYP2C8 by PPAR activators. PMID:26467040

  10. Boron carbide nanolumps on carbon nanotubes

    Science.gov (United States)

    Lao, J. Y.; Li, W. Z.; Wen, J. G.; Ren, Z. F.

    2002-01-01

    Boron carbide nanolumps are formed on the surface of multiwall carbon nanotubes by a solid-state reaction between boron and carbon nanotubes. The reaction is localized so that the integrity of the structure of carbon nanotubes is maintained. Inner layers of multiwall carbon nanotubes are also bonded to boron carbide nanolumps. These multiwall carbon nanotubes with boron carbide nanolumps are expected to be the ideal reinforcing fillers for high-performance composites because of the favorable morphology.

  11. NEW ADVANCES IN BORON SOIL CHEMISTRY

    Science.gov (United States)

    Boron is an essential micronutrient element required for plant growth. Boron deficiency is wide-spread in crop plants throughout the world especially in coarse-textured soils in humid areas. Boron toxicity can also occur, especially in arid regions under irrigation. Plants respond directly to the...

  12. Furin-processed antigens targeted to the secretory route elicit functional TAP1-/-CD8+ T lymphocytes in vivo.

    Science.gov (United States)

    Medina, Francisco; Ramos, Manuel; Iborra, Salvador; de León, Patricia; Rodríguez-Castro, Marta; Del Val, Margarita

    2009-10-01

    Most pathogen-derived peptides recognized by CD8+ CTL are produced by proteasomes and delivered to the endoplasmic reticulum by the TAP transporters associated with Ag processing. Alternative proteases also produce antigenic peptides, but their actual relevance is unclear. There is a need to quantify the contribution of these supplementary pathways in vitro and in vivo. A well-defined TAP-independent secretory route of Ag processing involves the trans-Golgi network protease furin. Quantitation of this route by using OVA constructs encoded by vaccinia viruses indicates that it provides approximately one-third of all surface complexes of peptide and MHC class I molecules. Generation of the epitope carboxyl terminus is a dramatic rate-limiting step, since bypassing it increased efficiency by at least 1000-fold. Notably, the secretory construct activated a similar percentage of Ag-specific CD8+ T cells in wild type as in TAP1-deficient mice, which allow only secretory routes but which have a 10- to 20-fold smaller CD8 compartment. Moreover, these TAP1(-/-) OVA-specific CD8+ T lymphocytes accomplished elimination of epitope-bearing cells in vivo. The results obtained with this experimental system underscore the potential of secretory pathways of MHC class I Ag presentation to elicit functional CD8+ T lymphocytes in vivo and support the hypothesis that noncytosolic processing mechanisms may compensate in vivo for the lack of proteasome participation in Ag processing in persons genetically deficient in TAP and thus contribute to pathogen control. PMID:19752221

  13. Isotopic distributions of the sup 1 sup 8 N fragmentation products in coincidence with neutrons on targets sup 1 sup 9 sup 7 Au and sup 9 Be

    CERN Document Server

    Li Xiang Qing; Ye Yan Lin; Hua Hui; Chen Tao; Li Zhi Huan; Ge Yuch Eng; Wang Quan Jin; Wu He Yu; Jin Ge; Duan Li Min; Xiao Zhi Gang; Wang Hong Wei; Li Zhu Yu; Wang Su Fang

    2002-01-01

    The authors present the experimental isotopic distributions of the sup 1 sup 8 N projectile fragmentation products Li, Be, B and C in coincidence with neutrons, as well as the inclusive ones on sup 1 sup 9 sup 7 Au and sup 9 Be targets. In the framework of the abrasion-ablation model, these distributions are calculated for various nucleon density distributions of the projectile. The comparison with experimental isotopic distributions of the projectile-like fragments in coincidence with neutrons shows that the information on the nucleon density distribution of the sup 1 sup 8 N projectile can be extracted

  14. Boron doping a semiconductor particle

    Science.gov (United States)

    Stevens, Gary Don; Reynolds, Jeffrey Scott; Brown, Louanne Kay

    1998-06-09

    A method (10,30) of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried (16), with the boron film then being driven (18) into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out (38) into piles and melted/fused (40) with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements.

  15. Pharmacological targeting of miR-155 via the NEDD8-activating enzyme inhibitor MLN4924 (Pevonedistat) in FLT3-ITD acute myeloid leukemia

    Science.gov (United States)

    Khalife, J; Radomska, HS; Santhanam, R; Huang, X; Neviani, P; Saultz, J; Wang, H; Wu, Y-Z; Alachkar, H; Anghelina, M; Dorrance, A; Curfman, J; Bloomfield, CD; Medeiros, BC; Perrotti, D; Lee, LJ; Lee, RJ; Caligiuri, MA; Pichiorri, F; Croce, CM; Garzon, R; Guzman, ML; Mendler, JH; Marcucci, G

    2016-01-01

    High levels of microRNA-155 (miR-155) are associated with poor outcome in acute myeloid leukemia (AML). In AML, miR-155 is regulated by NF-κB, the activity of which is, in part, controlled by the NEDD8-dependent ubiquitin ligases. We demonstrate that MLN4924, an inhibitor of NEDD8-activating enzyme presently being evaluated in clinical trials, decreases binding of NF-κB to the miR-155 promoter and downregulates miR-155 in AML cells. This results in the upregulation of the miR-155 targets SHIP1, an inhibitor of the PI3K/Akt pathway, and PU.1, a transcription factor important for myeloid differentiation, leading to monocytic differentiation and apoptosis. Consistent with these results, overexpression of miR-155 diminishes MLN4924-induced antileukemic effects. In vivo, MLN4924 reduces miR-155 expression and prolongs the survival of mice engrafted with leukemic cells. Our study demonstrates the potential of miR-155 as a novel therapeutic target in AML via pharmacologic interference with NF-κB-dependent regulatory mechanisms. We show the targeting of this oncogenic microRNA with MLN4924, a compound presently being evaluatedin clinical trials in AML. As high miR-155 levels have been consistently associated with aggressive clinical phenotypes, our work opens new avenues for microRNA-targeting therapeutic approaches to leukemia and cancer patients. PMID:25971362

  16. BdCESA7, BdCESA8, and BdPMT Utility Promoter Constructs for Targeted Expression to Secondary Cell-Wall-Forming Cells of Grasses

    OpenAIRE

    Petrik, Deborah L.; Cass, Cynthia L.; Padmakshan, Dharshana; Foster, Cliff E.; Vogel, John P; Steven D. Karlen; Ralph, John; Sedbrook, John C

    2016-01-01

    Utility vectors with promoters that confer desired spatial and temporal expression patterns are useful tools for studying gene and cellular function and for industrial applications. To target the expression of DNA sequences of interest to cells forming plant secondary cell walls, which generate most of the vegetative biomass, upstream regulatory sequences of the Brachypodium distachyon lignin biosynthetic gene BdPMT and the cellulose synthase genes BdCESA7 and BdCESA8 were isolated and cloned...

  17. Bone-targeted therapy for metastatic breast cancer—Where do we go from here? A commentary from the BONUS 8 meeting

    Directory of Open Access Journals (Sweden)

    Xiaofu Zhu

    2014-03-01

    Full Text Available The annual Bone and The Oncologist New Updates (BONUS 8 conference focuses on the current understanding and dilemmas in the treatment and prevention of bone metastasis in cancer, as well as novel research on bone homeostasis and cancer-induced bone loss. We present commentaries from experts for their own take on where they feel the field of bone-targeted therapies for metastatic breast cancer is moving, or needs to move, if we are to make further progress.

  18. Boron Clusters as Highly Stable Magnesium-Battery Electrolytes**

    OpenAIRE

    Carter, Tyler J; Mohtadi, Rana; Arthur, Timothy S; Mizuno, Fuminori; Zhang, Ruigang; Shirai, Soichi; Kampf, Jeff W.

    2014-01-01

    Boron clusters are proposed as a new concept for the design of magnesium-battery electrolytes that are magnesium-battery-compatible, highly stable, and noncorrosive. A novel carborane-based electrolyte incorporating an unprecedented magnesium-centered complex anion is reported and shown to perform well as a magnesium-battery electrolyte. This finding opens a new approach towards the design of electrolytes whose likelihood of meeting the challenging design targets for magnesium-battery electro...

  19. Boron Neutron Capture Therapy for Malignant Brain Tumors

    Science.gov (United States)

    MIYATAKE, Shin-Ichi; KAWABATA, Shinji; HIRAMATSU, Ryo; KUROIWA, Toshihiko; SUZUKI, Minoru; KONDO, Natsuko; ONO, Koji

    2016-01-01

    Boron neutron capture therapy (BNCT) is a biochemically targeted radiotherapy based on the nuclear capture and fission reactions that occur when non-radioactive boron-10, which is a constituent of natural elemental boron, is irradiated with low energy thermal neutrons to yield high linear energy transfer alpha particles and recoiling lithium-7 nuclei. Therefore, BNCT enables the application of a high dose of particle radiation selectively to tumor cells in which boron-10 compound has been accumulated. We applied BNCT using nuclear reactors for 167 cases of malignant brain tumors, including recurrent malignant gliomas, newly diagnosed malignant gliomas, and recurrent high-grade meningiomas from January 2002 to May 2014. Here, we review the principle and history of BNCT. In addition, we introduce fluoride-18-labeled boronophenylalanine positron emission tomography and the clinical results of BNCT for the above-mentioned malignant brain tumors. Finally, we discuss the recent development of accelerators producing epithermal neutron beams. This development could provide an alternative to the current use of specially modified nuclear reactors as a neutron source, and could allow BNCT to be performed in a hospital setting. PMID:27250576

  20. Effect of boron carbide on primary crystallization of chromium cast iron

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2008-04-01

    Full Text Available In the paper results of the influence of boron carbide (B4C as inoculant of abrasion-resisting chromium cast iron (about 2,8% carbon and 18% chromium on primary crystallization researches are presented. Boron carbide dispersion was introduced at the bottom of pouring ladle before tap of liquid cast iron. In this investigations were used three different quantities of inoculant in amounts 0,1%; 0,2% and 0,3% with relation to bath weight. It has been demonstrated that such small additions of boron carbide change primary crystallization parameters, particularly temperature characteristic of process, their time and kinetics.

  1. Dissolution Of The Rubidium From Eti Mine Kırka Boron Management Waste

    OpenAIRE

    BAYDIR, Ayşegül Türk; Erdoğan, Yunus

    2013-01-01

    XRF and XRD analyzes has been conducted of the samples that are obtained from Eti Mine Kırka Boron Management. XRF and XRD analysis results seem to support each other. According to the XRD analysis results, the samples obtained from Eti Mine Kırka Boron Management has been found Borax, dolomite, potassium feldspar, tinkalkonit structure. According to the results of XRF analysis in KK8 sample above 1000 µg/g Rb was determined. In this study, the sample is obtained from Eti Mine Kırka Boron Man...

  2. Boron steel. I Part. Preparation

    International Nuclear Information System (INIS)

    With the advent of the first nuclear reactors arise the need for control rods and shielding duties for some types of radiations. One of the materials used for this purpose has been the high boron steel. This paper describes the melting and casting procedures employed for the production, at laboratory scale, of steels with Boron content ranging from 1 to 4 per cent, as well as the metallographic and X-Ray techniques used for the identification of the present phases. The electrolytic technique employed for the isolation of the Fe2B phase and its subsequent X-Ray identification has proved to be satisfactory. (Author) 11 refs

  3. Shear amorphization of boron suboxide

    International Nuclear Information System (INIS)

    We report for the first time the shear-induced local amorphization of boron suboxide subjected to nanoindentation. The amorphous bands have a width of ∼1–3 nm and a length of 200–300 nm along the (01¯11) crystal plane. We show direct experimental evidence that the amorphous shear bands of boron suboxide are driven from the coalescence of dislocation loops under high shear stresses. These observations provide insights into the microscopic deformation and failure of high-strength and lightweight ceramics

  4. Thermal conductivity of boron carbides

    Science.gov (United States)

    Wood, C.; Emin, D.; Gray, P. E.

    1985-01-01

    Knowledge of the thermal conductivity of boron carbide is necessary to evaluate its potential for high-temperature thermoelectric energy conversion applications. Measurements have been conducted of the thermal diffusivity of hot-pressed boron carbide BxC samples as a function of composition (x in the range from 4 to 9), temperature (300-1700 K), and temperature cycling. These data, in concert with density and specific-heat data, yield the thermal conductivities of these materials. The results are discussed in terms of a structural model that has been previously advanced to explain the electronic transport data. Some novel mechanisms for thermal conduction are briefly discussed.

  5. Mechanical properties of boron coatings

    International Nuclear Information System (INIS)

    Internal stress of coatings will cause reliability problems, such as adhesion failure and peeling. We measured the internal stress in boron coatings, which was prepared by the ion plating method, with an apparatus based on the optically levered laser technique. The boron coatings exhibited large compressive stress in the range from -0.5 GPa to -2.6 GPa. It was found that these compressive stresses were decreasing functions of the deposition rate and were increasing functions of the ion bombardment energy. ((orig.))

  6. Structure-Based Design and Synthesis of Novel Inhibitors Targeting HDAC8 from Schistosoma mansoni for the Treatment of Schistosomiasis.

    Science.gov (United States)

    Heimburg, Tino; Chakrabarti, Alokta; Lancelot, Julien; Marek, Martin; Melesina, Jelena; Hauser, Alexander-Thomas; Shaik, Tajith B; Duclaud, Sylvie; Robaa, Dina; Erdmann, Frank; Schmidt, Matthias; Romier, Christophe; Pierce, Raymond J; Jung, Manfred; Sippl, Wolfgang

    2016-03-24

    Schistosomiasis is a major neglected parasitic disease that affects more than 265 million people worldwide and for which the control strategy consists of mass treatment with the only available drug, praziquantel. In this study, a series of new benzohydroxamates were prepared as potent inhibitors of Schistosoma mansoni histone deacetylase 8 (smHDAC8). Crystallographic analysis provided insights into the inhibition mode of smHDAC8 activity by these 3-amidobenzohydroxamates. The newly designed inhibitors were evaluated in screens for enzyme inhibitory activity against schistosome and human HDACs. Twenty-seven compounds were found to be active in the nanomolar range, and some of them showed selectivity toward smHDAC8 over the major human HDACs (1 and 6). The active benzohydroxamates were additionally screened for lethality against the schistosome larval stage using a fluorescence-based assay. Four of these showed significant dose-dependent killing of the schistosome larvae and markedly impaired egg laying of adult worm pairs maintained in culture. PMID:26937828

  7. Advanced scheme for high-yield laser driven proton-boron fusion reaction

    Czech Academy of Sciences Publication Activity Database

    Margarone, Daniele; Picciotto, A.; Velyhan, Andriy; Krása, Josef; Kucharik, M.; Morrissey, Michael; Mangione, A.; Szydlowsky, A.; Malinowska, A.; Bertuccio, G.; Shi, Y.; Crivellari, M.; Ullschmied, Jiří; Bellutti, P.; Korn, Georg

    Bellingham: SPIE, 2015 - (Awwal, A.; Lane, M.), "93450F-1"-"93450F-8". (Proceedings of SPIE. 9345). ISBN 978-1-62841-435-6. ISSN 0277-786X. [Biennial Conference on High Power Lasers for Fusion Research /3./. San Francisco (US), 20150210] R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279 Grant ostatní: ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : proton-boron fusion * advanced targets * laser-induced nuclear reactions Subject RIV: BF - Elementary Particles and High Energy Physics; BH - Optics, Masers, Lasers (UFP-V)

  8. Preparation and characterization of sputtered boron nitride and boron carbide films and their modification by ion implantation

    International Nuclear Information System (INIS)

    Nanocrystalline cubic boron nitride and boron carbide films have been synthesized using sputtering. The relationship between the structures and properties as well as the influence of the deposition parameters, such as rf power, bias voltage, substrate temperature, composition and flow rate of the sputtering gas, on the structures and properties have been studied. The influence of the ion bombardment could be described by the specific ion momentum P*=[ion momentum.(ion flux/atom flux)]. The specific ion momentum was found to be proportional to the rf power and to the 1.5th power of the bias voltage. Two phases have been identified in our boron nitride films: hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN); the films were either single phase or contained a mixture of these two phases. Nanocrystalline boron films have been grown with a deposition rate of 2 nm/s not only on Si but also on hard metal (WC-6%Co) substrates. Stoichiometric and crystalline films have already been grown at room temperature (about 0.1 Tm, Tm=melting point-3900 K). All the films contained about 8 at% carbon and 6 at% oxygen as impurities, which come mainly from the targt. The concentration of the impurities is independent of the deposition paramters. The growth of c-BN appears after the specific ion momentum larger than a threshold value, which is dependent on the substrate temperature, composition and on the flow rate of the sputtering gas. The volume content of c-BN runs through a maximum value with increasing specific ion momentum. (orig.)

  9. The K2 Ecliptic Plane Input Catalog (EPIC) and Stellar Classifications of 138,600 Targets in Campaigns 1-8

    Science.gov (United States)

    Huber, Daniel; Bryson, Stephen T.; Haas, Michael R.; Barclay, Thomas; Barentsen, Geert; Howell, Steve B.; Sharma, Sanjib; Stello, Dennis; Thompson, Susan E.

    2016-05-01

    The K2 Mission uses the Kepler spacecraft to obtain high-precision photometry over ≈80 day campaigns in the ecliptic plane. The Ecliptic Plane Input Catalog (EPIC) provides coordinates, photometry, and kinematics based on a federation of all-sky catalogs to support target selection and target management for the K2 mission. We describe the construction of the EPIC, as well as modifications and shortcomings of the catalog. Kepler magnitudes (Kp) are shown to be accurate to ≈0.1 mag for the Kepler field, and the EPIC is typically complete to Kp ≈ 17 (Kp ≈ 19 for campaigns covered by Sloan Digital Sky Survey). We furthermore classify 138,600 targets in Campaigns 1–8 (≈88% of the full target sample) using colors, proper motions, spectroscopy, parallaxes, and galactic population synthesis models, with typical uncertainties for G-type stars of ≈3% in {T}{{eff}}, ≈0.3 dex in {log} g, ≈40% in radius, ≈10% in mass, and ≈40% in distance. Our results show that stars targeted by K2 are dominated by K–M dwarfs (≈41% of all selected targets), F–G dwarfs (≈36%), and K giants (≈21%), consistent with key K2 science programs to search for transiting exoplanets and galactic archeology studies using oscillating red giants. However, we find significant variation of the fraction of cool dwarfs with galactic latitude, indicating a target selection bias due to interstellar reddening and increased contamination by giant stars near the galactic plane. We discuss possible systematic errors in the derived stellar properties, and differences with published classifications for K2 exoplanet host stars. The EPIC is hosted at the Mikulski Archive for Space Telescopes (MAST): http://archive.stsci.edu/k2/epic/search.php.

  10. Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy

    International Nuclear Information System (INIS)

    Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle's construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable size could possess some tumor selectivity. Consequently, the discovery of a very boron-rich nanoparticle delivery agent with biodistribution performance similar to unilamellar liposomes became one of our goals. Closomers, a new class of polyhedral borane derivatives, attracted us as an alternative BNCT drug-delivery system. We specifically envisioned dodeca (nido-carboranyl)-substituted closomers as possibly having a great potential role in BNCT drug delivery. They could function as extraordinarily boron-rich BNCT drugs since they are amphiphilic

  11. Boron-Containing Compounds for Liposome-Mediated Tumor Localization and Application to Neutron Capture Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M. Frederick [Univ. of California, Los Angeles, CA (United States)

    2005-04-07

    Medical application of boron neutron capture therapy (BNCT) has been significantly hindered by the slow development of boron drug-targeting methodologies for the selective delivery of high boron concentration sto malignant cells. We have successfully sought to fill this need by creating liposomes suitable as in vivo boron delivery vehicles for BNCT. Delivery of therapeutic quantities of boron to tumors in murine models has been achieved with small unilamellar boron-rich liposomes. Subsequently, attempts have been made to improve delivery efficiency of liposomes encapsulating boron-containing water-soluble species into their hollow core by incorporating lipophilic boron compounds as addenda to the liposome bilayer, incorporating boron compounds as structural components of the bilayer (which however, poses the risk of sacrificing some stability), and combinations thereof. Regardless of the method, approximately 90% of the total liposome mass remains therapeutically inactive and comprised of the vehicle's construction materials, while less than 5% is boron for neutron targeting. Following this laboratory's intensive study, the observed tumor specificity of certain liposomes has been attributed to their diminutive size of these liposomes (30-150 nm), which enables these small vesicles to pass through the porous, immature vasculature of rapidly growing tumor tissue. We surmised that any amphiphilic nanoparticle of suitable size could possess some tumor selectivity. Consequently, the discovery of a very boron-rich nanoparticle delivery agent with biodistribution performance similar to unilamellar liposomes became one of our goals. Closomers, a new class of polyhedral borane derivatives, attracted us as an alternative BNCT drug-delivery system. We specifically envisioned dodeca (nido-carboranyl)-substituted closomers as possibly having a great potential role in BNCT drug delivery. They could function as extraordinarily boron-rich BNCT drugs since they are

  12. Boron-enhanced diffusion of boron from ultralow-energy boron implantation

    International Nuclear Information System (INIS)

    The authors have investigated the diffusion enhancement mechanism of BED (boron enhanced diffusion), wherein the boron diffusivity is enhanced three to four times over the equilibrium diffusivity at 1,050 C in the proximity of a silicon layer containing a high boron concentration. It is shown that BED is associated with the formation of a fine-grain polycrystalline silicon boride phase within an initially amorphous Si layer having a high B concentration. For 0.5 keV B+, the threshold implantation dose which leads to BED lies between 3 x 1014 and of 1 x 1015/cm-2. Formation of the shallowest possible junctions by 0.5 keV B+ requires that the implant dose be kept lower than this threshold

  13. Optical absorption of boron nitride nanomaterials

    International Nuclear Information System (INIS)

    Optical absorption spectra have been measured for hexagonal boron nitride (h-BN), rhombohedral BN(rh-BN), and material obtained by laser vaporization of BN target under a nitrogen atmosphere and contained single-wall BN-nanotubes. Band gap of the BN materials was found to have a value of 6.0-6.3 eV. The spectra of h -BN and vaporized material exhibited a peak at ∝5.5 eV, moreover, the latter sample showed an absorption band around 4.5 eV. The vaporized material has been fractionated to the BN-platelets and single-wall BN-nanotubes. Absorption peaks, located bellow the bottom of the conductance band, were found to be characteristics of thin BN-platelets and they could be attributed to defects in BN network. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Spherical nucleic acid targeting microRNA-99b enhances intestinal MFG-E8 gene expression and restores enterocyte migration in lipopolysaccharide-induced septic mice

    Science.gov (United States)

    Wang, Xiao; Hao, Liangliang; Bu, Heng-Fu; Scott, Alexander W.; Tian, Ke; Liu, Fangyi; De Plaen, Isabelle G.; Liu, Yulan; Mirkin, Chad A.; Tan, Xiao-Di

    2016-01-01

    Milk fat globule-EGF factor 8 (MFG-E8) maintains the intestinal homeostasis by enhancing enterocyte migration and attenuating inflammation. We previously reported that sepsis is associated with down-regulation of intestinal MFG-E8 and impairment of enterocyte migration. Here, we showed that impairment of intestinal epithelial cell migration occurred in lipopolysaccharide (LPS)-induced septic mice. Treatment of RAW264.7 cells (a murine macrophage-like cell line) with LPS increased expression of miR-99b, a microRNA that is predicted to target mouse MFG-E8 3′UTR. Using a luciferase assay, we showed that miR-99b mimic suppressed the activity of a reporter containing MFG-E8 3′UTR. This suggests the role of miR-99b in inhibition of MFG-E8 gene expression. In addition, we developed an anti-miR99b spherical nucleic acid nanoparticle conjugate (SNA-NCanti-miR99b). Treatment of both naïve and LPS-challenged cells with SNA-NCanti-miR99b enhanced MFG-E8 expression in the cells. Administration of SNA-NCanti-miR99b rescued intestinal MFG-E8 expression in LPS-induced septic mice and attenuated LPS inhibitory effects on intestinal epithelial cell migration along the crypt-villus axis. Collectively, our study suggests that LPS represses MFG-E8 expression and disrupts enterocyte migration via a miR-99b dependent mechanism. Furthermore, this work shows that SNA-NCanti-miR99b is a novel nanoparticle-conjugate capable of rescuing MFG-E8 gene expression and maintaining intestinal epithelial homeostasis in sepsis. PMID:27538453

  15. Broadly targeted human cytomegalovirus-specific CD4+ and CD8+ T cells dominate the memory compartments of exposed subjects.

    Science.gov (United States)

    Sylwester, Andrew W; Mitchell, Bridget L; Edgar, John B; Taormina, Cara; Pelte, Christian; Ruchti, Franziska; Sleath, Paul R; Grabstein, Kenneth H; Hosken, Nancy A; Kern, Florian; Nelson, Jay A; Picker, Louis J

    2005-09-01

    Human cytomegalovirus (HCMV) infections of immunocompetent hosts are characterized by a dynamic, life-long interaction in which host immune responses, particularly of T cells, restrain viral replication and prevent disease but do not eliminate the virus or preclude transmission. Because HCMV is among the largest and most complex of known viruses, the T cell resources committed to maintaining this balance have never been characterized completely. Here, using cytokine flow cytometry and 13,687 overlapping 15mer peptides comprising 213 HCMV open reading frames (ORFs), we found that 151 HCMV ORFs were immunogenic for CD4(+) and/or CD8(+) T cells, and that ORF immunogenicity was influenced only modestly by ORF expression kinetics and function. We further documented that total HCMV-specific T cell responses in seropositive subjects were enormous, comprising on average approximately 10% of both the CD4(+) and CD8(+) memory compartments in blood, whereas cross-reactive recognition of HCMV proteins in seronegative individuals was limited to CD8(+) T cells and was rare. These data provide the first glimpse of the total human T cell response to a complex infectious agent and will provide insight into the rules governing immunodominance and cross-reactivity in complex viral infections of humans. PMID:16147978

  16. The CXCR3 targeting chemokine CXCL11 has potent antitumor activity in vivo involving attraction of CD8+ T lymphocytes but not inhibition of angiogenesis.

    Science.gov (United States)

    Hensbergen, Paul J; Wijnands, Pepijn G J T B; Schreurs, Marco W J; Scheper, Rik J; Willemze, Rein; Tensen, Cornelis P

    2005-01-01

    The IFN-gamma-inducible and CXCR3-targeting human CXC chemokines CXCL9 (Mig) and CXCL10 (IP10) have potent antitumor activity through attraction of cytotoxic T lymphocytes and inhibition of angiogenesis. The more recently identified CXCR3-targeting chemokine CXCL11 (I-TAC/IP9) proved to be a more potent chemokine than CXCL9 and CXCL10 in vitro, both in chemotaxis assays with CXCR3+ T lymphocytes and in calcium mobilization experiments. However, its antitumor activity in vivo has not been shown so far. To investigate this, mice were challenged with EL4 T-cell lymphoma cells, genetically modified to produce murine CXCL11. Tumor growth curves showed complete rejection of CXCL11-producing tumors but not of control tumors. Tumor infiltrate analysis by flow cytometry showed a clear correlation between rejection of CXCL11-producing tumors and an increase of tumor-infiltrating CD8+CXCR3+ as well as CD8+CXCR3- T lymphocytes. In vivo CD8 T-cell depletion completely abrogated the antitumor effect. No difference in angiogenesis between control and CXCL11-producing tumors was observed. In survivors, rechallenge experiments with wild-type tumor cells suggested development of protective antitumor immunity involving tumor-specific IFN-gamma production by CD8+ T lymphocytes. These experiments show, for the first time, antitumor activity of CXCL11 in vivo, which warrants exploration for its potential role in anticancer immunotherapy. PMID:16000952

  17. Analytical boron diffusivity model in silicon for thermal diffusion from boron silicate glass film

    Science.gov (United States)

    Kurachi, Ikuo; Yoshioka, Kentaro

    2015-09-01

    An analytical boron diffusivity model in silicon for thermal diffusion from a boron silicate glass (BSG) film has been proposed in terms of enhanced diffusion due to boron-silicon interstitial pair formation. The silicon interstitial generation is considered to be a result of the silicon kick-out mechanism by the diffused boron at the surface. The additional silicon interstitial generation in the bulk silicon is considered to be the dissociation of the diffused pairs. The former one causes the surface boron concentration dependent diffusion. The latter one causes the local boron concentration dependent diffusion. The calculated boron profiles based on the diffusivity model are confirmed to agree with the actual diffusion profiles measured by secondary ion mass spectroscopy (SIMS) for a wide range of the BSG boron concentration. This analytical diffusivity model is a helpful tool for p+ boron diffusion process optimization of n-type solar cell manufacturing.

  18. Analysis of boronized wall in LHD

    International Nuclear Information System (INIS)

    Boronization has been carried out in some experimental fusion devices as one of wall conditioning Methods. The well-known merits of the boronization are as follows: 1) coated-boron on the first wall has strong gettering function for oxygen impurities and oxygen has been kept into boron films as a boron-oxide and 2) boron film covers first wall with apparently low Z materials facing the plasma. However, an operation scenario of boronization for next generation devices such as ITER is not optimized. In this paper, we discuss an optimized method of coated film uniformity in a wide area and a lifetime of boron film as an oxygen getter using experimental data in the large helical device (LHD). In LHD, boronization by glow discharges has been carried out a few times during each experimental campaign. Helium-diborane mixtured gas is used and plasma facing components (PFM) are stainless steel (SS) for the first wall and carbon for the divertor plates kept in the room temperature. Material probes made of SS316 and Si were installed in the vacuum vessel and exposed during the experimental campaign. Depth profiles of their impurities were analyzed using the X-ray Photoelectron Spectroscopy (XPS) and the Auger electron spectroscopy (AES). Two types of gettering process by boron film have been investigated. One is the process during boronization and the other is that after boronization. Concerning a lifetime of boron film, the distribution of oxygen near the top surface region (0 to 20 nm) indicates a process of oxygen gettering, it shows a contribution after boronization. In this paper, these kinds of process using material probes are shown. (authors)

  19. Boron Poisoning of Plutonium Solutions

    International Nuclear Information System (INIS)

    The results of a theoretical investigation into the possible relaxation of criticality concentration limits in wet chemical reprocessing plants, due to the introduction of boron poisoning, are reported. The following systems were considered: 1. 1 in. stainless steel tubes filled with boron carbide at various pitches in homogeneous mixtures of 239Pu (NO3)4, 5H2O and water. 2. 1 in. and 2 in borosilicate glass Raschig rings in homogeneous mixtures of 239Pu (NO3)4, 5H2O and water. 3. The concentration of natural boron required for k∞ = 1 in homogeneous mixtures of 239Pu-B-H2O. The method of calculation was Monte Carlo using the GEM code with Nuclear Data File cross-sections. The Raschig rings used are those commercially available. The core model consisted of a cubic arrangement of unit cubes of solution within each of which a Raschig ring was centrally placed. The arrangement was such that the rings were regularly stacked with axes parallel, but the side of the unit cube was fixed to preserve the random packing density. Comparison is made with other reported results on boron poisoning. (author)

  20. Boron sorption characteristics in resins

    International Nuclear Information System (INIS)

    The purpose of boron addition in a nuclear power plant is to control the reactivity. In PHWRs, it is injected into the moderator system in the form of boric anhydride solution, while in PHWRs, it is added to the primary heat transport system in the form of boric acid solution. The required boron levels in PHWRs are controlled by valving in strong base anion exchangers having exchangeable species in OD- form while in PHWRs, the same can be achieved by restoring to the use of Boron Thermal Regeneration System (BTRS). This system operates on the principle of existence of different amounts of various polyborate ions at different temperatures, solution pH's and the boric acid concentrations and on the reversible sorption of these polyions on strong base anion exchange resins. This report describes the salient features of boron sorption characteristics on four types of anion exchange resins, based on experimental data generated in the chemical laboratories of Reactor Engineering Division of the Bhabha Atomic Research Centre, Bombay. The report further makes an attempt to calculate the pH of the resin and solution phases and the percentages of different polyborates and undissociated boric acid, under the experimental conditions investigated. (author). 30 refs., 4 figs., 20 tables

  1. Advanced microstructure of boron carbide.

    Science.gov (United States)

    Werheit, Helmut; Shalamberidze, Sulkhan

    2012-09-26

    The rhombohedral elementary cell of the complex boron carbide structure is composed of B(12) or B(11)C icosahedra and CBC, CBB or B□B (□, vacancy) linear arrangements, whose shares vary depending on the actual chemical compound. The evaluation of the IR phonon spectra of isotopically pure boron carbide yields the quantitative concentrations of these components within the homogeneity range. The structure formula of B(4.3)C at the carbon-rich limit of the homogeneity range is (B(11)C) (CBC)(0.91) (B□B)(0.09) (□, vacancy); and the actual structure formula of B(13)C(2) is (B(12))(0.5)(B(11)C)(0.5)(CBC)(0.65)(CBB)(0.16) (B□B)(0.19), and deviates fundamentally from (B(12))CBC, predicted by theory to be the energetically most favourable structure of boron carbide. In reality, it is the most distorted structure in the homogeneity range. The spectra of (nat)B(x)C make it evident that boron isotopes are not randomly distributed in the structure. However, doping with 2% silicon brings about a random distribution. PMID:22945740

  2. Boron isotopes in geothermal systems

    International Nuclear Information System (INIS)

    Boron is a highly mobile element and during water-rock reactions, boron is leached out of rocks with no apparent fractionation. In geothermal systems where the water recharging the systems are meteoric in origin, the B isotope ratio of the geothermal fluid reflects the B isotope ratio of the rocks. Seawater has a distinctive B isotope ratio and where seawater recharges the geothermal system, the B isotope ratio of the geothermal system reflects the mixing of rock derived B and seawater derived B. Any deviations of the actual B isotope ratio of a mixture reflects subtle differences in the water-rock ratios in the cold downwelling limb of the hydrothermal system. This paper will present data from a variety of different geothermal systems, including New Zealand; Iceland; Yellowston, USA; Ibusuki, Japan to show the range in B isotope ratios in active geothermal systems. Some of these systems show well defined mixing trends between seawater and the host rocks, whilst others show the boron isotope ratios of the host rock only. In geothermal systems containing high amounts of CO2 boron isotope ratios from a volatile B source can also be inferred. (auth)

  3. Identification of HLA-A*2402-restricted HCMV immediate early-1 (IE-1 epitopes as targets for CD8+ HCMV-specific cytotoxic T lymphocytes

    Directory of Open Access Journals (Sweden)

    Lee Sang-Guk

    2009-08-01

    Full Text Available Abstract Background To identify novel HLA-A*2402-restricted human cytomegalovirus (HCMV immediate early-1 (IE-1 epitopes for adoptive immunotherapy, we explored 120 overlapping 15-amino acid spanning IE-1. Methods These peptides were screened by measuring the frequency of polyclonal CD8+ T cells producing intracellular interferon-γ (IFN-γ using flow cytometry and the epitopes were validated with a HCMV-infected target Cr release cytotoxicity assay. Results Initial screening was performed with 12 mini-pools of 10 consecutive peptides made from 120 overlapping peptides15-amino acids in length that spanned IE-1. When peripheral blood mononuclear cells (PBMCs from HLA-A*2402 HCMV-seropositive donors were sensitized with each of the 12 mini-pools, mini-pools 1 and 2 induced the highest frequency of CD8+ cytotoxic T lymphocytes (CTLs producing IFN-γ. When PBMCs were stimulated with each of the twenty peptides belonging to mini-pools 1 and 2, peptides IE-11–15MESSAKRKMDPDNPD and IE-15–19AKRKMDPDNPDEGPS induced the greatest quantities of IFN-γ production and cytotoxicity of HLA-matched HCMV-infected fibroblasts. To determine the exact HLA-A*2402-restricted epitopes within the two IE-1 proteins, we synthesized a total of twenty-one overlapping 9- or 10 amino acid peptides spanning IE-11–15 and IE-15–19. Peptide IE-13–12SSAKRKMDPD induced the greatest quantities of IFN-γ production and target cell killing by CD8+ CTLs. Conclusion HCMV IE-13–12SSAKRKMDPD is a HLA-A*2402-restricted HCMV IE-1 epitope that can serve as a common target for CD8+ HCMV-specific CTLs.

  4. MicroRNA-100 suppresses the migration and invasion of breast cancer cells by targeting FZD-8 and inhibiting Wnt/β-catenin signaling pathway.

    Science.gov (United States)

    Jiang, Qian; He, Miao; Guan, Shu; Ma, Mengtao; Wu, Huizhe; Yu, Zhaojin; Jiang, Longyang; Wang, Yan; Zong, Xingyue; Jin, Feng; Wei, Minjie

    2016-04-01

    Wnt/β-catenin signaling pathway plays a major role in the cancer metastasis. Several microRNAs (miRNAs) are contributed to the inhibition of breast cancer metastasis. Here, we attempted to find novel targets and mechanisms of microRNA-100 (miR-100) in regulating the migration and invasion of breast cancer cells. In this study, we found that miR-100 expression was downregulated in human breast cancer tissues and cell lines. The overexpression of miR-100 inhibited the migration and invasion of MDA-MB-231 breast cancer cells. Inversely, the downregulation of miR-100 increased the migration and invasion of MCF-7 breast cancer cells. Furthermore, FZD-8, a receptor of Wnt/β-catenin signaling pathway, was demonstrated a direct target of miR-100. The overexpression of miR-100 decreased the expression levels not only FZD-8 but also the key components of Wnt/β-catenin pathway, including β-catenin, metalloproteniase-7 (MMP-7), T-cell factor-4 (TCF-4), and lymphoid enhancing factor-1 (LEF-1), and increased the protein expression levels of GSK-3β and p-GSK-3β in MDA-MB-231 cells, and the transfection of miR-100 inhibitor in MCF-7 cells showed the opposite effects. In addition, the expression of miR-100 was negatively correlated with the FZD-8 expression in human breast cancer tissues. Overall, these findings suggest that miR-100 suppresses the migration and invasion of breast cancer cells by targeting FZD-8 and inhibiting Wnt/β-catenin signaling pathway and manipulation of miR-100 may provide a promoting therapeutic strategy for cancer breast treatment. PMID:26537584

  5. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients

  6. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fogg, Mark [Department of Medicine, Brigham and Women' s Hospital (United States); Murphy, John R. [Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, MA 02118 (United States); Lorch, Jochen; Posner, Marshall [Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115 (United States); Wang, Fred, E-mail: fwang@research.bwh.harvard.edu [Department of Medicine, Brigham and Women' s Hospital (United States); Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 (United States)

    2013-07-05

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients.

  7. Investigation of effect of some factors on boron coprecipitaion from magnesium chloride brines by aluminium hydroxide

    International Nuclear Information System (INIS)

    The conditions of precipitation of boron with aluminium hydroxide from natural magnesium chloride solutions of different concentration and from artificial solutions of boric acid with the same content of magnesium chloride were investigated. The effect of acidity on precipitation of boron with aluminium hydroxide was investigated over the pH range from 4.5 to 8.0. The dependence of the degree of boron extraction on pH has two maxima and one minimum. For concentrated mother liquors the maximum is at pH=5.0, and for dilute ones, at pH=6.5. The nature of the metal hydroxide and of the anions present in the solutions affects the shift of the maximum and minimum of boron extraction. It has been established that with an increase in temperature from 15 deg C to 45 deg C boron precipitation from weakly acid solutions decreases as a result of destruction of the boron polyanions with the formation of orthoboric acid. In a weakly alkaline medium, however, boron extraction increases due to additional release of magnesium hydroxide

  8. Raman spectroscopy of boron carbides and related boron-containing materials

    International Nuclear Information System (INIS)

    Raman spectra of crystalline boron, boron carbide, boron arsenide (B12As2), and boron phosphide (B12P2) are reported. The spectra are compared with other boron-containing materials containing the boron icosahedron as a structural unit. The spectra exhibit similar features some of which correlate with the structure of the icosahedral units of the crystals. The highest Raman lines appear to be especially sensitive to the B-B distance in the polar triangle of the icosahedron. Such Raman structural markers are potentially useful in efforts to tailor electronic properties of these high temperature semiconductors and thermoelectrics

  9. Investigation of vital pathogenic target orotate phosphoribosyltransferases (OPRTase) from Thermus thermophilus HB8: Phylogenetic and molecular modeling approach.

    Science.gov (United States)

    Surekha, Kanagarajan; Prabhu, Damodharan; Richard, Mariadasse; Nachiappan, Mutharasappan; Biswal, Jayashree; Jeyakanthan, Jeyaraman

    2016-06-01

    Biosynthesis pathways of pyrimidine and purine are shown to play an important role in regular cellular activities. The biosynthesis can occur either through de novo or salvage pathways based on the requirement of the cell. The pyrimidine biosynthesis pathway has been linked to several disorders and various autoimmune diseases. Orotate phosphoribosyl transferase (OPRTase) is an important enzyme which catalyzes the conversion of orotate to orotate monophosphate in the fifth step of pyrimidine biosynthesis. Phylogenetic analysis of 228 OPRTase sequences shows the distribution of proteins across different living forms of life. High structural similarities between Thermusthermophilus and other organisms kindled us to concentrate on OPRTase as an anti-pathogenic target. In this study, a homology model of OPRTase was constructed using 2P1Z as a template. About 100ns molecular dynamics simulation was performed to investigate the conformational stability and dynamic patterns of the protein. The amino acid residues (Met1, Asp2, Glu43, Ala44, Glu47, Lys51, Ala157 and Leu158) lining in the binding site were predicted using SiteMap. Further, structure based virtual screening was performed on the predicted binding site using ChemBridge, Asinex, Binding, NCI, TosLab and Zinc databases. Compounds retrieved from the screening collections were manually clustered. The resultant protein-ligand complexes were subjected to molecular dynamics simulations, which further validates the binding modes of the hits. The study may provide better insight for designing potent anti-pathogenic agent. PMID:26861612

  10. Recent results at the SIRa test bench: diffusion properties of carbon graphite and B{sub 4}C targets

    Energy Technology Data Exchange (ETDEWEB)

    Landre-Pellemoine, F.; Barue, C.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Kandri-Rody, S.; Lecesne, N.; Leroy, R.; Lewitowicz, M.; Lichtenthaler, R.; Marry, C.; Maunoury, L.; Pacquet, J.Y.; Saint-Laurent, M.G.; Stodel, C.; Rataud, J.P.; Villari, A.C.C. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Angelique, J.C.; Orr, N.A. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France); Lichtenthaler, R. [IFUSP, Sao Paulo, S.P. (Brazil); Bajeat, O.; Clapier, F.; Ducourtieux, M.; Lau, C.; Obert, J. [Institut de Physique Nucleaire (IN2P3/CNRS), 91 - Orsay (France); Bennett, R. [CLRC, RAL, Chilton Oxon (United Kingdom)

    2000-07-01

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for {sup 6}He (T{sub 1/2} = 806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B{sub 4}C (Boron Carbide) have also been studied. Yields of 1.5 10{sup 8} pps and 10{sup 6} pps for {sup 6}He and {sup 8}He has been obtained. (authors)

  11. Biodistribution of Boron compounds in an experimental model of liver metastases for Boron Neutron Capture (BNCT) Studies

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10B carriers in tumors followed by irradiation with thermal or epithermal neutrons. The high linear energy transfer alpha particles and recoiling 7Li nuclei emitted during the capture of a thermal neutron by a 10B nucleus have a short range and a high biological effectiveness. Thus, BNCT would potentially target neoplastic tissue selectively. In previous studies we demonstrated the therapeutic efficacy of different BNCT protocols in an experimental model of oral cancer. More recently we performed experimental studies in normal rat liver that evidenced the feasibility of treating liver metastases employing a novel BNCT protocol proposed by JEC based on ex-situ treatment and partial liver auto-transplant. The aim of the present study was to perform biodistribution studies with different boron compounds and different administration protocols to determine the protocols that would be therapeutically useful in 'in vivo' BNCT studies at the RA-3 Nuclear Reactor in an experimental model of liver metastases in rats. Materials and Methods. A total of 70 BDIX rats (Charles River Lab., MA, USA) were inoculated in the liver with syngeneic colon cancer cells DH/DK12/TRb (ECACC, UK) to induce the development of subcapsular metastatic nodules. 15 days post-inoculation the animals were used for biodistribution studies. A total of 11 protocols were evaluated employing the boron compounds boronophenylalanine (BPA) and GB-10 (Na210B1-0H10), alone or combined employing different doses and administration routes. Tumor, normal tissue and blood samples were processed for boron measurement by ICP-OES. Results. Several protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue, i.e. BPA 15.5 mg 10B/kg iv + GB-10 50 mg 10B/kg iv; BPA 46.5 mg 10B/kg ip; BPA 46.5 mg 10B/kg ip + iv; BPA 46

  12. Correlation between radiation dose and histopathological findings in patients with gliblastoma treated with boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    The purpose of this study was to clarify the correlation between the radiation dose and histopathological findings in patients with glioblastoma multiforme (GBM) treated with boron neutron capture therapy (BNCT). Histopathological studies were performed on specimens from 8 patients, 3 had undergone salvage surgery and 5 were autopsied. For histopathological cure of GBM at the primary site, the optimal minimal dose to the gross tumor volume (GTV) and the clinical target volume (CTV) were 68 Gy(w) and 44 Gy(w), respectively. - Highlights: • It is very important to determine the curable BNCT radiation dose on histopathological aspect in BNCT. • Of 23 patients with GBM treated with BNCT, autopsy was performed in 5, salvage surgery in 3, and histopathological study in 8. • To achieve the histopathological cure of GBM at the primary site, the optimal minimal dose to the GTV and CTV was 68 Gy(w) and 44 Gy(w), respectively

  13. Synthesis of boron nitride nanotubes by boron ink annealing.

    Science.gov (United States)

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M

    2010-03-12

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs. PMID:20154372

  14. Synthesis of boron nitride nanotubes by boron ink annealing

    International Nuclear Information System (INIS)

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

  15. Synthesis of vinyl boronates from aldehydes by a practical boron-Wittig reaction.

    Science.gov (United States)

    Coombs, John R; Zhang, Liang; Morken, James P

    2015-04-01

    A highly stereoselective boron-Wittig reaction between stable and readily accessible 1,1-bis(pinacolboronates) and aldehydes furnishes a variety of synthetically useful di- and trisubstituted vinyl boronate esters. PMID:25799147

  16. WSP-Sprayed Boron Carbide Coatings for Fusion Applications

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Neufuss, Karel; Ctibor, Pavel; Rohan, Pavel; Dubský, Jiří; Chráska, Pavel; Brožek, Vlastimil

    Düsseldorf: DVS, 2002 - (Lugscheider, E.; Berndt, C.), s. 1-5 ISBN 3-87155-783-8. [International Thermal Spray Conference.. Essen (DE), 04.03.2002-06.03.2002] R&D Projects: GA ČR GA104/01/0149 Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal spray coatings, boron carbide, fusion reactor materials Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  17. Structural and mechanical properties of activated sintered boron carbide-based materials

    International Nuclear Information System (INIS)

    Boron carbide based materials (B4C-MexIV-VIBy) were obtained by pressureless sintering at 2150--2250 C in the presence of some transition metal (IV-VI group) carbides (MexIV-VICy, where Me is Ti, V, Cr, and W). The structural and mechanical (micro hardness, abrasive wear resistance) properties of these materials were studied. Changes of the boron carbide lattice parameters were observed after sintering. EDS analysis showed the presence of a transition metal phase in the boron carbide structure. A considerable increase in microhardness (76 GPa) and abrasive wear resistance values of the sintered materials (1.8 times as compared to pure hot-pressed B4C) was registered. A new class of superhard boron carbide-based materials was obtained by pressureless sintering. The materials processed by this method are promising for high performance applications

  18. In ovo administration of boron alters bone mineralization of the chicken embryo.

    Science.gov (United States)

    King, N; Odom, T W; Sampson, H W; Pardue, S L

    1991-07-01

    It has been hypothesized that boron (B) is an essential element for animals, especially in bone metabolism. In this study, the influence of in ovo boron administration was assessed in the chicken. At 8 d of embryogenesis, carrier or B (0.1, 0.5, or 1.0 mg) was injected on to the chorioallantoic membrane of fertile eggs. At hatching, body weights were recorded and tissue samples collected. Although boron failed to alter bone mineralization, it decreased (p less than 0.05) dried bone weight, suggesting a reduction in the bone organic matrix. Furthermore, 1 mg boron decreased (p less than 0.05) hatchability and increased (p less than 0.05) the height of the proliferative zone in the growth plate, indicating an unfavorable effect on bone elongation of the developing chick. PMID:1718368

  19. Microplasma Processed Ultrathin Boron Nitride Nanosheets for Polymer Nanocomposites with Enhanced Thermal Transport Performance.

    Science.gov (United States)

    Zhang, Ri-Chao; Sun, Dan; Lu, Ai; Askari, Sadegh; Macias-Montero, Manuel; Joseph, Paul; Dixon, Dorian; Ostrikov, Kostya; Maguire, Paul; Mariotti, Davide

    2016-06-01

    This Research Article reports on the enhancement of the thermal transport properties of nanocomposite materials containing hexagonal boron nitride in poly(vinyl alcohol) through room-temperature atmospheric pressure direct-current microplasma processing. Results show that the microplasma treatment leads to exfoliation of the hexagonal boron nitride in isopropyl alcohol, reducing the number of stacks from >30 to a few or single layers. The thermal diffusivity of the resulting nanocomposites reaches 8.5 mm(2) s(-1), 50 times greater than blank poly(vinyl alcohol) and twice that of nanocomposites containing nonplasma treated boron nitride nanosheets. From TEM analysis, we observe much less aggregation of the nanosheets after plasma processing along with indications of an amorphous carbon interfacial layer, which may contribute to stable dispersion of boron nitride nanosheets in the resulting plasma treated colloids. PMID:27153343

  20. Synthesis of Boron Nanowires, Nanotubes, and Nanosheets

    Directory of Open Access Journals (Sweden)

    Rajen B. Patel

    2015-01-01

    Full Text Available The synthesis of boron nanowires, nanotubes, and nanosheets using a thermal vapor deposition process is reported. This work confirms previous research and provides a new method capable of synthesizing boron nanomaterials. The materials were made by using various combinations of MgB2, Mg(BH42, MCM-41, NiB, and Fe wire. Unlike previously reported methods, a nanoparticle catalyst and a silicate substrate are not required for synthesis. Two types of boron nanowires, boron nanotubes, and boron nanosheets were made. Their morphology and chemical composition were determined through the use of scanning electron microscopy, transmission electron microscopy, and electron energy loss spectroscopy. These boron-based materials have potential for electronic and hydrogen storage applications.

  1. Microwave sintering of boron carbide composites

    International Nuclear Information System (INIS)

    Boron carbide is an important ceramic material because of its high hardness and low specific gravity. it is used for applications involving impact and wear resistance. The disadvantages of boron carbide materials are difficulty in fabrication and sensitivity to brittle fracture. These problems are significantly reduced by production of cermets based on boron carbide and aluminum or aluminum alloys. Microwave heating of boron carbide materials results in ultrarapid heating and high temperatures. Therefore, a finer microstructure is obtained. The objective of this work was to define a technology that would allow the manufacture of boron carbide ceramics having mechanical properties similar to those exhibited by hot-pressed specimens. microwave heating would be used for the densification step. Mixtures of boron carbide and aluminum were considered for this research because aluminum simultaneously acts as a sintering aid and introduces phases that contribute to toughness enhancement

  2. Prediction of boron carbon nitrogen phase diagram

    Science.gov (United States)

    Yao, Sanxi; Zhang, Hantao; Widom, Michael

    We studied the phase diagram of boron, carbon and nitrogen, including the boron-carbon and boron-nitrogen binaries and the boron-carbon-nitrogen ternary. Based on the idea of electron counting and using a technique of mixing similar primitive cells, we constructed many ''electron precise'' structures. First principles calculation is performed on these structures, with either zero or high pressures. For the BN binary, our calculation confirms that a rhmobohedral phase can be stablized at high pressure, consistent with some experimental results. For the BCN ternary, a new ground state structure is discovered and an Ising-like phase transition is suggested. Moreover, we modeled BCN ternary phase diagram and show continuous solubility from boron carbide to the boron subnitride phase.

  3. Boronic acid functionalized superparamagnetic iron oxide nanoparticle as a novel tool for adsorption of sugar

    International Nuclear Information System (INIS)

    Synthesis of boronic acid functionalized superparamagnetic iron oxide nanoparticles has been reported. Magnetite nanoparticles were prepared by simple co-precipitation from Fe2+ and Fe3+ solution. m-Aminophenyl boronic acid was attached to iron oxide particles through 3,4-dihydroxy benzaldehyde through C=N bond. X-ray diffraction and selected area electron diffraction have shown the formation of inverse spinel phase magnetite of both as prepared and functionalized magnetite particles. FTIR shows attachment of boronic acid-imine onto iron oxide surface through enediol group. Transmission electron microscopy shows well dispersion of boronic acid functionalized particles of size 8 ± 2 nm. Vibration sample magnetometry shows both the particles are superparamagnetic at room temperature having saturation magnetization (Ms) 52 emu/g. In this work the affinity of these boronic acid functionalized particles towards sugar binding was studied taking dextrose sugar as a model. The influence of pH and sugar concentration has been extensively investigated. The results show that such boronic acid modified superparamagnetic particles are efficient support for sugar separation having maximum sugar loading capacity (60 μg/50 μl) at pH 8.

  4. Boronic acid functionalized superparamagnetic iron oxide nanoparticle as a novel tool for adsorption of sugar

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, S., E-mail: sasmita05@gmail.com [Department of Chemistry, National Institute of Technology, Rourkela-769008 (India); Panda, N. [Department of Chemistry, National Institute of Technology, Rourkela-769008 (India); Pramanik, P. [Department of Chemistry, Indian Institute of Technology, Kharagpur-721302 (India)

    2009-08-31

    Synthesis of boronic acid functionalized superparamagnetic iron oxide nanoparticles has been reported. Magnetite nanoparticles were prepared by simple co-precipitation from Fe{sup 2+} and Fe{sup 3+} solution. m-Aminophenyl boronic acid was attached to iron oxide particles through 3,4-dihydroxy benzaldehyde through C=N bond. X-ray diffraction and selected area electron diffraction have shown the formation of inverse spinel phase magnetite of both as prepared and functionalized magnetite particles. FTIR shows attachment of boronic acid-imine onto iron oxide surface through enediol group. Transmission electron microscopy shows well dispersion of boronic acid functionalized particles of size 8 {+-} 2 nm. Vibration sample magnetometry shows both the particles are superparamagnetic at room temperature having saturation magnetization (Ms) 52 emu/g. In this work the affinity of these boronic acid functionalized particles towards sugar binding was studied taking dextrose sugar as a model. The influence of pH and sugar concentration has been extensively investigated. The results show that such boronic acid modified superparamagnetic particles are efficient support for sugar separation having maximum sugar loading capacity (60 {mu}g/50 {mu}l) at pH 8.

  5. Geochemical study of boron isotopes in the process of loess weathering

    Institute of Scientific and Technical Information of China (English)

    赵志琦; 刘丛强; 肖应凯; 郎赟超

    2003-01-01

    In this paper the boron contents and boron isotopic composition of acid-soluble phases in loess and paleosol samples are determined for the first time. The boron contents of acid-soluble phases in the Luochuan loess section (S0 -S2) vary within the range of (0.8-2.7)×10-6 and theirδ11B values vary from -1.8‰ to +18.6‰, mostly within the range of 0-+10‰. The boron contents andδ11B values of paleosol layers are higher than those of loess layers, especially in the loess layer S1. Varying chemical weathering intensity and loess adsorption capability are the main factors leading to the variations of boron contents and δ11B values of acid-soluble phases in the loess section. The variation of chemical weathering intensity in response to the variation of climatic conditions seems to be the main factor leading to the variations of boron contents andδ11B values of acid-soluble phases in the loess section.

  6. Boron clusters in luminescent materials.

    Science.gov (United States)

    Mukherjee, Sanjoy; Thilagar, Pakkirisamy

    2016-01-21

    In recent times, luminescent materials with tunable emission properties have found applications in almost all aspects of modern material sciences. Any discussion on the recent developments in luminescent materials would be incomplete if one does not account for the versatile photophysical features of boron containing compounds. Apart from triarylboranes and tetra-coordinate borate dyes, luminescent materials consisting of boron clusters have also found immense interest in recent times. Recent studies have unveiled the opportunities hidden within boranes, carboranes and metalloboranes, etc. as active constituents of luminescent materials. From simple illustrations of luminescence, to advanced applications in LASERs, OLEDs and bioimaging, etc., the unique features of such compounds and their promising versatility have already been established. In this review, recent revelations about the excellent photophysical properties of such materials are discussed. PMID:26574714

  7. Mammalian Target of Rapamycin Complex 2 Controls CD8 T Cell Memory Differentiation in a Foxo1-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Lianjun Zhang

    2016-02-01

    Full Text Available Upon infection, antigen-specific naive CD8 T cells are activated and differentiate into short-lived effector cells (SLECs and memory precursor cells (MPECs. The underlying signaling pathways remain largely unresolved. We show that Rictor, the core component of mammalian target of rapamycin complex 2 (mTORC2, regulates SLEC and MPEC commitment. Rictor deficiency favors memory formation and increases IL-2 secretion capacity without dampening effector functions. Moreover, mTORC2-deficient memory T cells mount more potent recall responses. Enhanced memory formation in the absence of mTORC2 was associated with Eomes and Tcf-1 upregulation, repression of T-bet, enhanced mitochondrial spare respiratory capacity, and fatty acid oxidation. This transcriptional and metabolic reprogramming is mainly driven by nuclear stabilization of Foxo1. Silencing of Foxo1 reversed the increased MPEC differentiation and IL-2 production and led to an impaired recall response of Rictor KO memory T cells. Therefore, mTORC2 is a critical regulator of CD8 T cell differentiation and may be an important target for immunotherapy interventions.

  8. Conduction mechanism in boron carbide

    Science.gov (United States)

    Wood, C.; Emin, D.

    1984-01-01

    Electrical conductivity, Seebeck-coefficient, and Hall-effect measurements have been made on single-phase boron carbides, B(1-x)C(x), in the compositional range from 0.1 to 0.2 X, and between room temperature and 1273 K. The results indicate that the predominant conduction mechanism is small-polaron hopping between carbon atoms at geometrically inequivalent sites.

  9. Sintering behavior of boron carbide

    International Nuclear Information System (INIS)

    Pressureless sintering behavior of boron carbide (B4C) in argon was studied, with change in time and temperature, using carbon as sintering aid. Carbon was added via fenolic resin, acting also as a binder. After isostatic pressing the specimens were sintered in a graphite furnace at 19600C/1h, 21600C/15 minutes and 1h and 22000C/1h. The achieved density was 97% of the theoretical. Some mechanical properties and microstructural aspects have been evaluated. (author)

  10. Boron Enrichment in Martian Clay

    OpenAIRE

    James D Stephenson; Lydia J Hallis; Kazuhide Nagashima; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest minera...

  11. Boron deposition from fused salts. Final report

    International Nuclear Information System (INIS)

    A partial evaluation of the feasibility of a process to electrodeposit pure coherent coatings of elemental boron from molten fluorides has been performed. The deposit produced was powdery and acicular, unless the fluoride melt was purified to have very low oxygen concentration. When the oxygen activity was reduced in the melt by addition of crystalline elemental boron, dense, amorphous boron deposit was produced. The boron deposits produced had cracks but were otherwise pure and dense and ranged up to 0.35 mm thick. Information derived during this project suggests that similar deposits might be obtained crack-free up to 1.00 mm thick by process modifications and improvements

  12. Genomic and Immunological Tumor Profiling Identifies Targetable Pathways and Extensive CD8+/PDL1+ Immune Infiltration in Inflammatory Breast Cancer Tumors.

    Science.gov (United States)

    Hamm, Christopher A; Moran, Diarmuid; Rao, Kakuturu; Trusk, Patricia B; Pry, Karen; Sausen, Mark; Jones, Siân; Velculescu, Victor E; Cristofanilli, Massimo; Bacus, Sarah

    2016-07-01

    Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer that remains poorly understood at the molecular level. Comprehensive tumor profiling was performed to understand clinically actionable alterations in IBC. Targeted next-generation sequencing (NGS) and IHC were performed to identify activated pathways in IBC tumor tissues. siRNA studies examined the impact of IBC genomic variants in cellular models. IBC tumor tissues were further characterized for immune infiltration and immune checkpoint expression by IHC. Genomic analysis identified recurrent alterations in core biologic pathways, including activating and targetable variants in HER/PI3K/mTOR signaling. High rates of activating HER3 point mutations were discovered in IBC tumors. Cell line studies confirmed a role for mutant HER3 in IBC cell proliferation. Immunologic analysis revealed a subset of IBC tumors associated with high CD8(+)/PD-L1(+) lymphocyte infiltration. Immune infiltration positively correlated with an NGS-based estimate of neoantigen exposure derived from the somatic mutation rate and mutant allele frequency, iScore. Additionally, DNA mismatch repair alterations, which may contribute to higher iScores, occurred at greater frequency in tumors with higher immune infiltration. Our study identifies genomic alterations that mechanistically contribute to oncogenic signaling in IBC and provides a genetic basis for the selection of clinically relevant targeted and combination therapeutic strategies. Furthermore, an NGS-based estimate of neoantigen exposure developed in this study (iScore) may be a useful biomarker to predict immune infiltration in IBC and other cancers. The iScore may be associated with greater levels of response to immunotherapies, such as PD-L1/PD-1-targeted therapies. Mol Cancer Ther; 15(7); 1746-56. ©2016 AACR. PMID:27196778

  13. Three-chain B{sub 6n+14} cages as possible precursors for the syntheses of boron fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Haigang, E-mail: luhg@sxu.edu.cn; Li, Si-Dian [Key Laboratory of Chemical Biology and Molecular Engineering of the Education Ministry, Institute of Molecular Science, Shanxi University, Taiyuan, Shanxi 030006 (China)

    2013-12-14

    Using the first principle methods, we proposed a series of three-chain boron cages B{sub 6n+14} (n = 1–12) which are mainly built by fusing three boron semi-double-rings. Their simple geometric structures (approximate D{sub 3} or C{sub 3} symmetry) facilitate their bottom-up syntheses from the hexagonal B{sub 7} and the double-chain boron clusters, such as B{sub 2}, B{sub 4}, B{sub 6}, B{sub 8}H{sub 2}, B{sub 10}H{sub 2}, B{sub 12}H{sub 2}, and the double ring B{sub 20}. The spherical shapes of these three-chain boron cages show that they could be taken as the possible precursors to further synthesize the boron fullerenes, such as B{sub 80}. Therefore, these three-chain boron cages provide a possible synthesis pathway of the boron fullerenes from the experimentally synthesized small planar boron clusters.

  14. Optimal timing of neutron irradiation for boron neutron capture therapy after intravenous infusion of sodium borocaptate in patients with glioblastoma

    International Nuclear Information System (INIS)

    Purpose: A cooperative study in Europe and Japan was conducted to determine the pharmacokinetics and boron uptake of sodium borocaptate (BSH: Na2B12H11SH), which has been introduced clinically as a boron carrier for boron neutron capture therapy in patients with glioblastoma. Methods and Materials: Data from 56 patients with glioblastoma who received BSH intravenous infusion were retrospectively reviewed. The pharmacokinetics were evaluated in 50 patients, and boron uptake was investigated in 47 patients. Patients received BSH doses between 12 and 100 mg/kg of body weight. For the evaluation, the infused boron dose was scaled linearly to 100 mg/kg BSH. Results: In BSH pharmacokinetics, the average value for total body clearance, distribution volume of steady state, and mean residence time was 3.6±1.5 L/h, 223.3±160.7 L, and 68.0±52.5 h, respectively. The average values of the boron concentration in tumor adjusted to 100 mg/kg BSH, the boron concentration in blood adjusted to 100 mg/kg BSH, and the tumor/blood boron concentration ratio were 37.1±35.8 ppm, 35.2±41.8 ppm, and 1.53±1.43, respectively. A good correlation was found between the logarithmic value of Tadj and the interval from BSH infusion to tumor tissue sampling. About 12-19 h after infusion, the actual values for Tadj and tumor/blood boron concentration ratio were 46.2±36.0 ppm and 1.70±1.06, respectively. The dose ratio between tumor and healthy tissue peaked in the same interval. Conclusion: For boron neutron capture therapy using BSH administered by intravenous infusion, this work confirms that neutron irradiation is optimal around 12-19 h after the infusion is started

  15. Development and Kinetics of TiB2 Layers on the Surface of Titanium Alloy by Superplastic Boronizing

    Science.gov (United States)

    Taazim, Nor Taibah; Jauhari, Iswadi; Miyashita, Yukio; Sabri, Mohd Faizul Mohd

    2016-05-01

    The aim of this work is to explore the possibility of combining boronizing and superplastic deformation on titanium alloy (Ti6Al4V) substrate. Superplastic boronizing (SPB) is carried out at three different temperatures of 1173 K, 1223 K, and 1273 K (900 °C, 950 °C, and 1000 °C), and it is held for four different boronizing times of 1, 2, 3, and 6 hours. TiB2 is the only boride compound identified after the boronizing process. Boronized layer thickness in the range of 44.9 ± 1.1 to 149 ± 1 μm is formed on the surface of Ti6Al4V and the surface hardness values increase with respect of the formation's degree of the hard boronized layer. Diffusion coefficient values attained for all temperatures are (1.44 ± 0.8) × 10-13, (4.1 ± 1.5) × 10-13, and (8.86 ± 4.1) × 10-13 m2 s-1, respectively and the values are higher as compared to other works referred. The activation energy obtained for this process is 226.17 ± 8.3 kJ mol-1. The results obtained suggest that the SPB process provides a more competent and efficient process for the formation of a boronized layer on the alloy.

  16. Identification of aryl hydrocarbon receptor binding targets in mouse hepatic tissue treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Raymond; Celius, Trine [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Forgacs, Agnes L. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Dere, Edward [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); MacPherson, Laura [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Harper, Patricia [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Research Institute, The Hospital for Sick Children, Toronto, Ontario (Canada); Zacharewski, Timothy [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Matthews, Jason, E-mail: jason.matthews@utoronto.ca [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada)

    2011-11-15

    Genome-wide, promoter-focused ChIP-chip analysis of hepatic aryl hydrocarbon receptor (AHR) binding sites was conducted in 8-week old female C57BL/6 treated with 30 {mu}g/kg/body weight 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 2 h and 24 h. These studies identified 1642 and 508 AHR-bound regions at 2 h and 24 h, respectively. A total of 430 AHR-bound regions were common between the two time points, corresponding to 403 unique genes. Comparison with previous AHR ChIP-chip studies in mouse hepatoma cells revealed that only 62 of the putative target genes overlapped with the 2 h AHR-bound regions in vivo. Transcription factor binding site analysis revealed an over-representation of aryl hydrocarbon response elements (AHREs) in AHR-bound regions with 53% (2 h) and 68% (24 h) of them containing at least one AHRE. In addition to AHREs, E2f-Myc activator motifs previously implicated in AHR function, as well as a number of other motifs, including Sp1, nuclear receptor subfamily 2 factor, and early growth response factor motifs were also identified. Expression microarray studies identified 133 unique genes differentially regulated after 4 h treatment with TCDD. Of which, 39 were identified as AHR-bound genes at 2 h. Ingenuity Pathway Analysis on the 39 AHR-bound TCDD responsive genes identified potential perturbation in biological processes such as lipid metabolism, drug metabolism, and endocrine system development as a result of TCDD-mediated AHR activation. Our findings identify direct AHR target genes in vivo, highlight in vitro and in vivo differences in AHR signaling and show that AHR recruitment does not necessarily result in changes in target gene expression. -- Highlights: Black-Right-Pointing-Pointer ChIP-chip analysis of hepatic AHR binding after 2 h and 24 h of TCDD. Black-Right-Pointing-Pointer We identified 1642 and 508 AHR-bound regions at 2 h and 24 h. Black-Right-Pointing-Pointer 430 regions were common to both time points and highly enriched with

  17. Method for determination of boron carbide in wurtzite-like boron nitride

    International Nuclear Information System (INIS)

    A technique for increase of sensitivity and analysis accuracy while boron carbide determination in wurtzite-like boron nitride is proposed. Boron nitride with an addition of boron carbide is bjected to treatment by the mixture of concentrated sulphuric acid and 0.1-0.5 N of porassium bichromate solution at ratio of (2-1):1 at the temperature of mixture boiling. Boron carboide content is calculated according to the quantity of restored Cr(3+), which is determined by titration of Cr(6+) excess with the Mohr's salt solution

  18. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Durmazucar, Hasan H.; Guenduez, Guengoer E-mail: ggunduz@metu.edu.tr

    2000-12-01

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed.

  19. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    International Nuclear Information System (INIS)

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed

  20. Helium behaviour in implanted boron carbide

    Directory of Open Access Journals (Sweden)

    Motte Vianney

    2015-01-01

    Full Text Available When boron carbide is used as a neutron absorber in nuclear power plants, large quantities of helium are produced. To simulate the gas behaviour, helium implantations were carried out in boron carbide. The samples were then annealed up to 1500 °C in order to observe the influence of temperature and duration of annealing. The determination of the helium diffusion coefficient was carried out using the 3He(d,p4He nuclear reaction (NRA method. From the evolution of the width of implanted 3He helium profiles (fluence 1 × 1015/cm2, 3 MeV corresponding to a maximum helium concentration of about 1020/cm3 as a function of annealing temperatures, an Arrhenius diagram was plotted and an apparent diffusion coefficient was deduced (Ea = 0.52 ± 0.11 eV/atom. The dynamic of helium clusters was observed by transmission electron microscopy (TEM of samples implanted with 1.5 × 1016/cm2, 2.8 to 3 MeV 4He ions, leading to an implanted slab about 1 μm wide with a maximum helium concentration of about 1021/cm3. After annealing at 900 °C and 1100 °C, small (5–20 nm flat oriented bubbles appeared in the grain, then at the grain boundaries. At 1500 °C, due to long-range diffusion, intra-granular bubbles were no longer observed; helium segregates at the grain boundaries, either as bubbles or inducing grain boundaries opening.

  1. Boron neutron capture therapy for recurrent head and neck malignancies

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a tumor-cell targeted radiotherapy. When 10B absorbs thermal neutrons, the alpha and 7Li particles generated by the 10B (n, α) 7Li reaction are high linear energy transfer (LET) particles, and carry high kinetic energy (2.34 MeV), and have short ranges (4-9 micron-meters) of approximately one-cell diameter, resulting in a large relative biological effectiveness (RBE) and selective destruction of tumor cells containing 10B. We have, for the first time in the world, used BNCT to treat 11 patients with recurrent head and neck malignancies (HNM) after a standard primary therapy since 2001. The 11 patients were composed of 6 squamous cell carcinomas, 3 salivary gland tumors and 2 sarcomas. The results of BNCT were as follows. Regression rates (volume %) were complete response (CR): 2 cases, >90%: 5 cases, 73%: 1 case, 54%: 1 case, progressive disease (PD): 1 case, NE (not evaluated): 1 case. The response rate was 82%. Improvement of quality of life (QOL) was recognized, such as disappearance of tumor ulceration and covering with normal skin: relief of severe pain, bleeding, trismus and dyspnea: improvement of performance status (PS) (from 4 to 2) allowing the patients to return to work and elongate his survival period. Survival periods after BNCT were 1-38 months (mean: 8.5 months). The survival rate was 36% (4 cases). There are a few side-effects such as transient mucositis and alopecia less than Grade-2. These results indicate that BNCT represents a new and promising treatment approach even for a huge or far-advanced HNM. (author)

  2. Some physical properties of compacted specimens of highly dispersed boron carbide and boron suboxide

    International Nuclear Information System (INIS)

    Structure, shear modulus and internal friction (IF) of compacted specimens of boron carbide and boron suboxide have been investigated. Microtwins and stacking faults were observed along the {100} plane systems of polycrystalline specimens of boron carbide. Electrical conductivity of the specimens was that of p-type. Concentration of holes varied from 1017 to 1019 cm-3. The IF was measured in the temperature range 80-300 K. It was shown that the IF of boron carbide and that of boron suboxide were characterized with a set of similar relaxation processes. Mechanisms of the relaxation processes in boron carbide and boron suboxide are discussed in terms of the Hasiguti model of interaction between dislocations and point defects

  3. Studies related to antibody-mediated boron delivery for BNCT

    International Nuclear Information System (INIS)

    Of the many methods of selective boron delivery to tumor presently under consideration the use of boron-labeled tumor-targeted monoclonal antibodies (Mabs) and their immunoreactive fragments appears to offer the most general, but complex, approach. Assuming that tumor cells generally carry 106 characteristic antigenic sites of any one type and that there are approximately 109 cells per gram of tumor, one calculates that about 600 10B atoms must be attached to each individual Mab molecule (if all antigenic sites are complexed) for each 10 ppm of 10B supplied to tumor. Rather than randomly attack IgG Mab molecules with a large number of relatively small boron-containing conjugation reagent molecules the authors have chosen to assemble a series of discrete, precisely synthesized oligomeric reagents ('trailers') each of which contains a fixed number of B-atoms up to approximately 200. These oligomeric reagents would carry a radioactive or fluorescent group for analytical purposes attached to a terminal-NH2 group of their chain and the remaining -COOH terminus would be free for conjugation with the lysine var-epsilon-NH2 groups of Mab protein. Two types of oligomeric trailer reagents are envisioned; hydrophilic peptides and polyamides

  4. Study the gas sensing properties of boron nitride nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Sajjad, Muhammad; Feng, Peter, E-mail: p.feng@upr.edu

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized boron nitride nanosheets (BNNSs) on silicon substrate. • We analyzed gas sensing properties of BNNSs-based gas-sensor device. • CH{sub 4} gas is used to measure gas-sensing properties of the device. • Quick response and recovery time of the device is recorded. • BNNSs showed excellent sensitivity to the working gas. - Abstract: In the present communication, we report on the synthesis of boron nitride nanosheets (BNNSs) and study of their gas sensing properties. BNNSs are synthesized by irradiating pyrolytic hexagonal boron nitride (h-BN) target using CO{sub 2} laser pulses. High resolution transmission electron microscopic measurements (HRTEM) revealed 2-dientional honeycomb crystal lattice structure of BNNSs. HRTEM, electron diffraction, XRD and Raman scattering measurements clearly identified h-BN. Gas sensing properties of synthesized BNNSs were analyzed with prototype gas sensor using methane as working gas. A systematic response curve of the sensor is recorded in each cycle of gas “in” and “out”; suggesting excellent sensitivity and high performance of BNNSs-based gas-sensor.

  5. Termite resistance of MDF panels treated with various boron compounds.

    Science.gov (United States)

    Usta, Mustafa; Ustaomer, Derya; Kartal, Saip Nami; Ondaral, Sedat

    2009-06-01

    In this study, the effects of various boron compounds on the termite resistance of MDF panels were evaluated. Either borax (BX), boric acid (BA), zinc borate (ZB), or sodium perborate tetrahydrate (SPT) were added to urea-formaldehyde (UF) resin at target contents of 1%, 1.5%, 2% and 2.5% based on dry fiber weight. The panels were then manufactured using 12% urea-formaldehyde resin and 1% NH(4)Cl. MDF samples from the panels were tested against the subterranean termites, Coptotermes formosanus Shiraki. Laboratory termite resistance tests showed that all samples containing boron compounds had greater resistance against termite attack compared to untreated MDF samples. At the second and third weeks of exposure, nearly 100% termite mortalities were recorded in all boron compound treated samples. The highest termite mortalities were determined in the samples with either BA or BX. Also, it was found that SPT showed notable performance on the termite mortality. As chemical loadings increased, termite mortalities increased, and at the same time the weight losses of the samples decreased. PMID:19582229

  6. Termite Resistance of MDF Panels Treated with Various Boron Compounds

    Directory of Open Access Journals (Sweden)

    Sedat Ondaral

    2009-06-01

    Full Text Available In this study, the effects of various boron compounds on the termite resistance of MDF panels were evaluated. Either borax (BX, boric acid (BA, zinc borate (ZB, or sodium perborate tetrahydrate (SPT were added to urea-formaldehyde (UF resin at target contents of 1%, 1.5%, 2% and 2.5% based on dry fiber weight. The panels were then manufactured using 12% urea-formaldehyde resin and 1% NH4Cl. MDF samples from the panels were tested against the subterranean termites, Coptotermes formosanus Shiraki. Laboratory termite resistance tests showed that all samples containing boron compounds had greater resistance against termite attack compared to untreated MDF samples. At the second and third weeks of exposure, nearly 100% termite mortalities were recorded in all boron compound treated samples. The highest termite mortalities were determined in the samples with either BA or BX. Also, it was found that SPT showed notable performance on the termite mortality. As chemical loadings increased, termite mortalities increased, and at the same time the weight losses of the samples decreased.

  7. A Preliminary experimental study of the boron concentration in vapor and the isotopic A preliminary experimental study of the boron concentrationin vapor and the isotopic fractionation of boron betweenseawater and vapor during evaporation of seawater

    Institute of Scientific and Technical Information of China (English)

    XIAO; Yingkai

    2001-01-01

    [1]Gast, J. A., Thompson, T. G., Evaporation of boric acid from seawater, Tellus, 1959, 6: 344-347.[2]Nishimura, M., Tanaka, K., Seawater may not be a source of boron in the atmosphere, J. Geoph. Res., 1972, 77: 5239-5242.[3]Fogg, T. R., Duce, R. A., Fasching, J. L., Sampling and determination of boron in the atmosphere, Anal. Chem., 1983, 55:2179-2184.[4]Fogg, T. R., Duce, R. A., Boron in the troposphere: Distribution and fluxes, J. Geoph. Res., 1985, 90: 3781-3796.[5]Spivack, A. J., Berndt, M. E., Seyfreid, W. E., Boron isotope fractionation during supercritical phase separation, Geochim.Cosmochim. Acta, 1990, 54: 2337-2339.[6]Palmer, M. R., London, D., Morgan, G. B. et al., Experimental determination of fractionation of 11B/10B between tourma-line and aqueous vapor: A temperature and pressure-dependent isotopic system, Chem. Geol., 1992, 101:123-129.[7]Hervig, R. L., London, D., Morgan, G. B. et al., Large boron isotope fractionation between hydrous vapor and silicate meltat igneous temperatures, in the Seventh Annual V. M. Goldschmidt Conf., LPI Contribution No. 921, Houston: Lunar and Planetary Institute, 1997, 93-94.[8]Vengosh, A., Starinsky, A., Kolodny, Y. et al., Boron isotope variations during fractional evaporation of seawater: New constraints on the marine vs. nonmarine debate, Geology, 1992, 20: 799-802.[9]Zhang, X. P., Shi, Y. E, Yao, T. D., The variation characteristics of δo18O in precipitation in Northeastern Qing-Zhang Plateau, Science in China, Series B (in Chinese), 1995, 25(5): 540-547.[10]Yu, J. S., Yu, E J., Liu, D. P., The hydrogen and oxygen of isotopic compositions of meteoric water in the eastern part of China, Geochimica (in Chinese), 1987, (1): 22-26.[11]Xiao, Y. K., Xiao, Y., Swihart, G. H. et al., Separation of boron by ion exchange with boron specific resin, Acta Geosci.Sinica (in Chinese), 1997, 18: 286-289.[12]Kiss, E., Ion-exchange separation and spectrophotometric determination of

  8. Boron carbide synthesis by carbothermic reduction of boron oxide

    International Nuclear Information System (INIS)

    Boron carbide (B4C) is a ceramic material of technological applications due to its extreme hardness and high chemical as well as thermal stability. Some parameters of the process for obtaining B4C by carbothermic reduction of B2O3 have been determined. The starting powders and the final products have been analysed by chemical, spectrographic and X-ray diffraction methods. The results show that the B4C obtained by the carbothermic reduction process is suitable for applications with a definite determination of the free carbon content. (author)

  9. Investigation of Properties of Asphalt Concrete Containing Boron Waste as Mineral Filler

    Directory of Open Access Journals (Sweden)

    Cahit GÜRER

    2016-05-01

    Full Text Available During the manufacture of compounds in the boron mining industry a large quantity of waste boron is produced which has detrimental effects on the environment. Large areas have to be allocated for the disposal of this waste. Today with an increase in infrastructure construction, more efficient use of the existing sources of raw materials has become an obligation and this involves the recycling of various waste materials. Road construction requires a significant amount of raw materials and it is possible that substantial amounts of boron-containing waste materials can be recycled in these applications. This study investigates the usability of boron wastes as filler in asphalt concrete. For this purpose, asphalt concrete samples were produced using mineral fillers containing 4%, 5%, 6%, 7% and 8% boron waste as well as a 6% limestone filler (6%L as the control sample. The Marshall Design, mechanical immersion and Marshall Stability test after a freeze-thaw cycle and indirect tensile stiffness modulus (ITSM test were performed for each of the series. The results of this experimental study showed that boron waste can be used in medium and low trafficked asphalt concrete pavements wearing courses as filler.

  10. Investigation of Properties of Asphalt Concrete Containing Boron Waste as Mineral Filler

    Directory of Open Access Journals (Sweden)

    Cahit GÜRER

    2016-03-01

    Full Text Available During the manufacture of compounds in the boron mining industry a large quantity of waste boron is produced which has detrimental effects on the environment. Large areas have to be allocated for the disposal of this waste. Today with an increase in infrastructure construction, more efficient use of the existing sources of raw materials has become an obligation and this involves the recycling of various waste materials. Road construction requires a significant amount of raw materials and it is possible that substantial amounts of boron-containing waste materials can be recycled in these applications. This study investigates the usability of boron wastes as filler in asphalt concrete. For this purpose, asphalt concrete samples were produced using mineral fillers containing 4%, 5%, 6%, 7% and 8% boron waste as well as a 6% limestone filler (6%L as the control sample. The Marshall design, mechanical immersion and Marshall stability test after a freeze-thaw cycle and indirect tensile stiffness modulus (ITSM test were performed for each of the series. The results of this experimental study showed that boron waste can be used in medium and low trafficked asphalt concrete pavements wearing courses as filler.

  11. Enhanced boronizing kinetics of alloy steel assisted by surface mechanical attrition treatment

    International Nuclear Information System (INIS)

    Highlights: • Nanostructured surface layer is fabricated on H13 steel assisted by SMAT. • The boronizing kinetics of SMAT sample can be enhanced remarkably. • Borided layer can delay fatigue cracks initiation and impede their propagation. -- Abstract: A nanostructured surface layer was fabricated on AISI H13 steel by means of surface mechanical attrition treatment (SMAT). Boronizing behaviors of the SMAT samples were systematically investigated in comparison with their coarse-grained counterparts. The boron diffusion depth of the SMAT sample with pack boriding treatment at 600 °C for 2 h was about 8 μm, which was much deeper than that of the coarse-grained sample. A much thicker borided layer on the SMAT sample can be synthesized by a duplex boronizing treatment at 600 °C followed by at a higher temperature. The borided layer was composed with monophase of Fe2B and the growth of it exhibited a (0 0 2) preferred orientation. Moreover, the activation energy of boron diffusion for the SMAT sample is 140.3 kJ/mol, which is much lower than 209.4 kJ/mol for the coarse-grained counterpart. The results indicate that the boronizing kinetics can be significantly enhanced in the SMAT sample with a duplex boronizing treatment. Furthermore, the thermal fatigue tests show that the borided layer with excellent oxidation resistance and mechanical strength at elevated temperatures could effectively delay the thermal fatigue cracks initiation and impede their propagation. Therefore, the thermal fatigue property of H13 steel with a duplex boronizing treatment can be improved remarkably

  12. Methods for separating boron from borated paraffin wax and its determination by ion chromatography

    International Nuclear Information System (INIS)

    Boron compounds are found to be useful in shielding against high-energy neutrons. In radiotherapy treatments, in order to protect occupational workers and patients from the undesirable neutron and gamma doses, paraffin wax containing B4C/boric acid is used. Low-level borate wastes generated from the nuclear power plants have been immobilized with paraffin wax using a concentrate waste drying system (CWDS). Borated paraffin waxes are prepared by mixing calculated amounts of either boric acid or boron carbide with the molten wax. This necessitates the determination of boron at different locations in order to check the homogeneous distribution of B over the borated wax. The determination of boron in nuclear materials is inevitable due to its high neutron absorption cross section. For the determination of boron in borated waxes, not many methods have been reported. A method based on the pyrohydrolysis extraction of boron and its quantification with ion chromatography was proposed for paraffin waxes borated with H3BO3 and B4C. The B4C optimum pyrohydrolysis conditions were identified. Wax samples were mixed with U3O8, which prevents the sample from flare up, and also accelerates the extraction of boron. Pyrohydrolysis was carried out with moist O2 at 950℃ for 60 and 90 min for wax with H3BO3 and wax with B4C, respectively. Two simple methods of separation based on alkali extraction and melting wax in alkali were also developed exclusively for wax with H3BO3. In all the separations, the recovery of B was above 98%. During IC separation, B was separated as boron-mannitol anion complex. Linear calibration was obtained between 0.1 and 50 ppm of B, and LOD was calculated as 5 ppb (S/N=3). The reproducibility was better than 5% (RSD)

  13. Treatment of hypophosphatasia by muscle-directed expression of bone-targeted alkaline phosphatase via self-complementary AAV8 vector

    Science.gov (United States)

    Nakamura-Takahashi, Aki; Miyake, Koichi; Watanabe, Atsushi; Hirai, Yukihiko; Iijima, Osamu; Miyake, Noriko; Adachi, Kumi; Nitahara-Kasahara, Yuko; Kinoshita, Hideaki; Noguchi, Taku; Abe, Shinichi; Narisawa, Sonoko; Millán, Jose Luis; Shimada, Takashi; Okada, Takashi

    2016-01-01

    Hypophosphatasia (HPP) is an inherited disease caused by genetic mutations in the gene encoding tissue-nonspecific alkaline phosphatase (TNALP). This results in defects in bone and tooth mineralization. We recently demonstrated that TNALP-deficient (Akp2−/−) mice, which mimic the phenotype of the severe infantile form of HPP, can be treated by intravenous injection of a recombinant adeno-associated virus (rAAV) expressing bone-targeted TNALP with deca-aspartates at the C-terminus (TNALP-D10) driven by the tissue-nonspecific CAG promoter. To develop a safer and more clinically applicable transduction strategy for HPP gene therapy, we constructed a self-complementary type 8 AAV (scAAV8) vector that expresses TNALP-D10 via the muscle creatine kinase (MCK) promoter (scAAV8-MCK-TNALP-D10) and examined the efficacy of muscle-directed gene therapy. When scAAV8-MCK-TNALP-D10 was injected into the bilateral quadriceps of neonatal Akp2−/− mice, the treated mice grew well and survived for more than 3 months, with a healthy appearance and normal locomotion. Improved bone architecture, but limited elongation of the long bone, was demonstrated on X-ray images. Micro-CT analysis showed hypomineralization and abnormal architecture of the trabecular bone in the epiphysis. These results suggest that rAAV-mediated, muscle-specific expression of TNALP-D10 represents a safe and practical option to treat the severe infantile form of HPP. PMID:26904710

  14. Disruption of SUMO-targeted ubiquitin ligases Slx5-Slx8/RNF4 alters RecQ-like helicase Sgs1/BLM localization in yeast and human cells.

    Science.gov (United States)

    Böhm, Stefanie; Mihalevic, Michael Joseph; Casal, Morgan Alexandra; Bernstein, Kara Anne

    2015-02-01

    RecQ-like helicases are a highly conserved protein family that functions during DNA repair and, when mutated in humans, is associated with cancer and/or premature aging syndromes. The budding yeast RecQ-like helicase Sgs1 has important functions in double-strand break (DSB) repair of exogenously induced breaks, as well as those that arise endogenously, for example during DNA replication. To further investigate Sgs1's regulation, we analyzed the subcellular localization of a fluorescent fusion of Sgs1 upon DNA damage. Consistent with a role in DSB repair, Sgs1 recruitment into nuclear foci in asynchronous cultures increases after ionizing radiation (IR) and after exposure to the alkylating agent methyl methanesulfonate (MMS). Yet, despite the importance of Sgs1 in replicative damage repair and in contrast to its elevated protein levels during S-phase, we find that the number of Sgs1 foci decreases upon nucleotide pool depletion by hydroxyurea (HU) treatment and that this negative regulation depends on the intra S-phase checkpoint kinase Mec1. Importantly, we identify the SUMO-targeted ubiquitin ligase (STUbL) complex Slx5-Slx8 as a negative regulator of Sgs1 foci, both spontaneously and upon replicative damage. Slx5-Slx8 regulation of Sgs1 foci is likely conserved in eukaryotes, since expression of the mammalian Slx5-Slx8 functional homologue, RNF4, restores Sgs1 focus number in slx8 cells and furthermore, knockdown of RNF4 leads to more BLM foci in U-2 OS cells. Our results point to a model where RecQ-like helicase subcellular localization is regulated by STUbLs in response to DNA damage, presumably to prevent illegitimate recombination events. PMID:25588990

  15. Spin dependent transport and magnetic properties in Fe{sub 4}N/tris(8-hydroxyquinoline) aluminum/Co organic spin valves fabricated by facing-target sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zirun [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Wang, Xiaocha [Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384 (China); Dai, Haitao [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Mi, Wenbo, E-mail: miwenbo@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Bai, Haili [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China)

    2015-08-03

    Spin-dependent electronic transport and magnetic properties of Fe{sub 4}N/tris(8-hydroxyquinoline) aluminum (Alq{sub 3})/Co organic spin valves (OSVs) are investigated. Fe{sub 4}N/Alq{sub 3}/Co OSVs with different Alq{sub 3} thicknesses t exhibit an inverse magnetoresistance (MR), which comes from the opposite effective spin polarization at the two ferromagnetic electrode/Alq{sub 3} interfaces. For the antiparallel configurations, MR at 3 K presents the obvious asymmetry, corresponding to the asymmetric hysteresis loop. The asymmetric loops of magnetization and MR can be attributed to the magnetic coupling at the Alq{sub 3}/Co interface. The interfacial diffusion between Co and Alq{sub 3} is weak due to the advantages of facing-target sputtering. Below 120 nm, MR increases with the increased t owing to the decreased effect of the ill-defined layer. The reduced MR at 260 nm is ascribed to the decline of spin polarization. - Highlights: • Fe{sub 4}N/Alq{sub 3}/Co organic spin valves exhibit an inverse magnetoresistance. • Asymmetric magnetoresistance is attributed to interfacial magnetic coupling. • The advantages of facing-target sputtering make interfacial diffusion weak.

  16. Study of nuclear reactions and analog isobar states in the system He8 + p for low energy with the help of MAYA active target

    International Nuclear Information System (INIS)

    With the resent improvements in the field of exotics beams, and specially with the SPIRAL facility at GANIL, we were able to study He9 shell inversion already known for Be11 and Li10, which are two members of the N=7 family. A new detector was developed and also the software tools for the data analysis. This detector is at the same time the target (active-target) and is called MAYA. The He9 was studied by determining the properties of its isobaric analogue states in Li9. The characteristics of the IAS (isomeric analog state) states were determined by an analysis of the resonances in the elastic scattering cross section for He8 + p from 2 up to 3.9 MeV/n. A study of (p,d) and (p,t) reactions was done too, in this domain of energy. By comparing the experimental results with calculations, an assignation of spin and parity for two states in He9 was possible. (author)

  17. Possible toxicity of boron on sugar cane

    Energy Technology Data Exchange (ETDEWEB)

    Bravo C., M.

    Analyses of necrotic and green leaf tissues from sugar cane grown in the Tambo Valley (Arequipa, Peru) have shown that the boron concentration in necrotic tissue (average 657.7 ppm) is several times higher than that in the green tissue (average 55.7 ppm). This suggests that the necrosis may be due to boron toxicity.

  18. New techniques for producing thin boron films

    International Nuclear Information System (INIS)

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs

  19. Fabrication of boron-phosphide neutron detectors

    International Nuclear Information System (INIS)

    Boron phosphide is a potentially viable candidate for high neutron flux neutron detectors. The authors have explored chemical vapor deposition methods to produce such detectors and have not been able to produce good boron phosphide coatings on silicon carbide substrates. However, semi-conducting quality films have been produced. Further testing is required

  20. Computational Evidence for the Smallest Boron Nanotube

    Institute of Scientific and Technical Information of China (English)

    Xian Jie LIN; Dong Ju ZHANG; Cheng Bu LIU

    2006-01-01

    The structure of boron nanotubes (BNTs) was found not to be limited to hexagonal pyramidal structures. Based on density functional theory calculations we provided evidence for the smallest boron nanotube, a geometrical analog of the corresponding carbon nanotube. As shown by our calculations, the smallest BNT possesses highly structural, dynamical, and thermal stability, which should be interest for attempts at its synthesis.

  1. Boron carbide whiskers produced by vapor deposition

    Science.gov (United States)

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  2. Boron Carbides As Thermo-electric Materials

    Science.gov (United States)

    Wood, Charles

    1988-01-01

    Report reviews recent theoretical and experimental research on thermoelectric materials. Recent work with narrow-band semiconductors demonstrated possibility of relatively high thermoelectric energy-conversion efficiencies in materials withstanding high temperatures needed to attain such efficiencies. Among promising semiconductors are boron-rich borides, especially boron carbides.

  3. Nuclear fuel management and boron carbide coating

    International Nuclear Information System (INIS)

    In recent years one way of introducing burnable absorber is to coat the fuel pellets by a thin layer of burnable absorber so called integral fuel burnable absorber (IFBA). In this method the fuel is coated with boron nitride or boron carbide. Boron has low absorption cross-section and when it exists on the surface of the fuel, it interacts with thermalized neutron. B4C is a boron compound, which can be used for coating the nuclear fuel. It has high thermal stability and withstands high pressure and temperatures. High technology product of boron carbide has different ratio of B: C. But in nuclear reactor when boron carbide is used, it must be rich with boron. In this research chemical vapor decomposition (CVD) has been using boron trichloride and carbon tetra chloride for reactant materials. The experiments were carried out at high temperatures (1050 degree Celsius, 1225 degree Celsius and 1325 degree Celsius). The coated samples were analyzed using X-Ray diffractometer (XRD), scanning electron microscopy (SEM) and will be presented in this paper. It was seen that decreasing the reaction temperature caused an increase on the quality and thickness of the coating

  4. Boron isotope composition of geothermal fluids and borate minerals from salar deposits (central Andes/NW Argentina)

    Science.gov (United States)

    Kasemann, Simone A.; Meixner, Anette; Erzinger, Jörg; Viramonte, José G.; Alonso, Ricardo N.; Franz, Gerhard

    2004-06-01

    We have measured the boron concentration and isotope composition of regionally expansive borate deposits and geothermal fluids from the Cenozoic geothermal system of the Argentine Puna Plateau in the central Andes. The borate minerals borax, colemanite, hydroboracite, inderite, inyoite, kernite, teruggite, tincalconite, and ulexite span a wide range of δ11B values from -29.5 to -0.3‰, whereas fluids cover a range from -18.3 to 0.7‰. The data from recent coexisting borate minerals and fluids allow for the calculation of the isotope composition of the ancient mineralizing fluids and thus for the constraint of the isotope composition of the source rocks sampled by the fluids. The boron isotope composition of ancient mineralizing fluids appears uniform throughout the section of precipitates at a given locality and similar to values obtained from recent thermal fluids. These findings support models that suggest uniform and stable climatic, magmatic, and tectonic conditions during the past 8 million years in this part of the central Andes. Boron in fluids is derived from different sources, depending on the drainage system and local country rocks. One significant boron source is the Paleozoic basement, which has a whole-rock isotopic composition of δ11B=-8.9±2.2‰ (1 SD); another important boron contribution comes from Neogene-Pleistocene ignimbrites ( δ11B=-3.8±2.8‰, 1 SD). Cenozoic andesites and Mesozoic limestones ( δ11B≤+8‰) provide a potential third boron source.

  5. Development of a boron-copper neutron absorber composite

    International Nuclear Information System (INIS)

    This report describes the fabrication of a new boron-copper neutron absorbing material that was developed to meet the upgrading needs of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory. To increase the intensity of the neutron beams from the IPNS, the target uranium was changed from depleted uranium to uranium enriched to 77.5% 235U. To keep the multiplication factor, keff (number of fissions in one generation/number of fissions in preceding generation) at a safe level, a new neutron absorber material was needed. The previous materials, boral and cadmium, could not meet the new requirements and a search of the literature showed that no currently available material was acceptable. With previous powder metallurgy used as a base, the composite was fabricated with 43 vol. % 10B (81% enriched 10B) and the balance copper and voids. The powder metallurgy techniques was followed by hot-rolling the composite to a sheet. The material composed of boron particles dispersed in a pure copper matrix and clad with pure copper on both sides, exhibits the following properties: Loadings up to 43 vol. % boron, with the balance copper and voids. A loading of 0.5 x 102210B atoms/cm2 in sections as thin as 0.067 in. (1.7 mm), with copper cladding as thin as 0.010 in. (0.25 mm). Formability to radii as small as 2.1 in. (53.3 mm). No observed reaction between boron and the copper matrix and cladding at temperatures up to 900 degrees C for times as long as 7 h. Retains structural integrity at 900 degrees C

  6. Comparison of the Level of Boron Concentrations in Black Teas with Fruit Teas Available on the Polish Market

    Directory of Open Access Journals (Sweden)

    Anetta Zioła-Frankowska

    2014-01-01

    Full Text Available The determination of boron by inductively coupled plasma-atomic emission spectrometry has been carried in water-soluble and acid soluble (total content fractions of 36 samples of traditional black tea and fruit brew. The estimation of the impact of the type of tea on the concentration of boron in water-soluble and acid extracts and potential human health risk from the daily intake of boron was carried out in this study. The levels of boron differed significantly in black and fruit tea types. The mean total content of boron ranged from 8.31 to 18.40 mg/kg in black teas, from 12.85 to 15.13 mg/kg in black tea with fruit flavor, and from 12.09 to 22.77 mg/kg in fruit brews. The degree of extraction of boron in black tea ranged from 8% to 27% and for fruit tea from 17% to 69%. In addition, the values below 25% were of black teas with fruit flavors. The daily intake of B from tea infusions (three cups/day is still within the average daily intake except for some of the fruit brews which exceed acceptable regulations of the daily intake of total boron by humans. Hence, it may not produce any health risks for human consumption, if other sources of metal contaminated food are not taken at the same time.

  7. Effect of Boron on Microstructure and Mechanical Properties of Hot-Rolled Nb-ADDED Hsla H-Section Steel

    Science.gov (United States)

    Wang, Zuocheng; Cui, Guotao; Sun, Tao; Guo, Weimin; Zhao, Xiuling; Gao, Junqing; Dong, Changxing

    In our research, boron was added into the Nb-added high strength low alloy (HSLA) H-section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H-section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

  8. Enhanced survival of glioma bearing rats using a combination of boronated epidermal growth factor and boronophenylalanine

    International Nuclear Information System (INIS)

    Following intratumoral (i.t.) injection, boronated epidermal growth factor (BSD-EGF) selectively targeted F98EGFR gliomas. Using BSD-EGF as the capture agent survival times were significantly increased over those observed in rats bearing F98 wildtype tumors following BNCT. These were further increased by the combination BSD-EGF with i.v. BPA. (author)

  9. XPS analysis of boron doped heterofullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, B.; Koetz, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muhr, H.J.; Nesper, R. [ETH Zurich, Zurich (Switzerland)

    1997-06-01

    Boron heterofullerenes were generated through arc-evaporation of doped graphite rods in a helium atmosphere. According to mass spectrometric analysis only mono-substituted fullerenes like C{sub 59}B, C{sub 69}B and higher homologues together with a large fraction of higher undoped fullerenes were extracted and enriched when pyridine was used as the solvent. XPS analysis of the extracts indicated the presence of two boron species with significantly different binding energies. One peak was assigned to borid acid. The second one corresponds to boron in the fullerene cage, which is mainly C{sub 59}B, according to the mass spectrum. This boron is in a somewhat higher oxidation state than that of ordinary boron-carbon compounds. The reported synthesis and extraction procedure opens a viable route for production of macroscopic amounts of these compounds. (author) 2 figs., 1 tab., 7 refs.

  10. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    10B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH)4-) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10B and 11B

  11. Stabilization of boron carbide via silicon doping.

    Science.gov (United States)

    Proctor, J E; Bhakhri, V; Hao, R; Prior, T J; Scheler, T; Gregoryanz, E; Chhowalla, M; Giulani, F

    2015-01-14

    Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in the material, and this raises the possibility of doping the boron carbide to eliminate this polytype. In this work, we have synthesized boron carbide doped with silicon. We have conducted a series of characterizations (transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and x-ray diffraction) on pure and silicon-doped boron carbide following static compression to 50 GPa non-hydrostatic pressure. We find that the level of amorphization under static non-hydrostatic pressure is drastically reduced by the silicon doping. PMID:25427850

  12. Stabilization of boron carbide via silicon doping

    Science.gov (United States)

    Proctor, J. E.; Bhakhri, V.; Hao, R.; Prior, T. J.; Scheler, T.; Gregoryanz, E.; Chhowalla, M.; Giulani, F.

    2015-01-01

    Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in the material, and this raises the possibility of doping the boron carbide to eliminate this polytype. In this work, we have synthesized boron carbide doped with silicon. We have conducted a series of characterizations (transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and x-ray diffraction) on pure and silicon-doped boron carbide following static compression to 50 GPa non-hydrostatic pressure. We find that the level of amorphization under static non-hydrostatic pressure is drastically reduced by the silicon doping.

  13. A comparative study of two digestion methods employed for the determination boron in ferroboron used as an advanced shielding material

    International Nuclear Information System (INIS)

    Shielding of nuclear reactor core is an important requirement of fast reactors. An important objective of future Fast Breeder Reactors (FBRs) is to reduce the volume of shields. A large number of materials have been considered for use to reduce the neutron flux to acceptable levels. A shield material which brings down the energy of neutrons by elastic and inelastic scattering along with absorption will be more effective. Ferro boron is identified as one of the advanced shielding materials considered for use in future FBRs, planned to be constructed in India. Ferroboron is an economical and indigenously available material which qualifies as a promising shield material through literature survey and scoping calculations. Experiments have been conducted in KAMINI reactor to understand the effectiveness of prospective shield material Ferro-boron as an in-core shield material for future FBRs. The Ferro boron used in these experiments contained 11.8% and 15% of boron. Precise determination of boron content in these ferro boron samples is very important to determine its effectiveness as a shield material. In this work a comparative study was carried out to determine the boron content in ferro boron samples. In the first method the sample was treated with incremental amounts of nitric acid under reflux (to prevent rigorous reaction and volatalisation of boron). The solution was gradually heated and the solution was filtered through a Whatman Filter paper no. 41. The undissolved ferro boron residue collected in the filter paper after filtration, is transferred to a platinum crucible; mixed with sodium carbonate and is ashed. The crucible is placed over a burner for 1 h to fuse the contents. The fused mass is leached in dilute hydrochloric acid, added to the nitric acid filtrate and made up to pre-determined volume

  14. Sodium borocaptate (BSH) for Boron Neutron Capture Therapy (BNCT) in the hamster cheek pouch oral cancer model: boron biodistribution at 9 post administration time-points

    International Nuclear Information System (INIS)

    The therapeutic success of Boron Neutron Capture Therapy (BNCT) depends centrally on boron concentration in tumor and healthy tissue. We previously demonstrated the therapeutic efficacy of boronophenylalanine (BPA) and sodium decahydrodecaborate (GB-10) as boron carriers for BNCT in the hamster cheek pouch oral cancer model. Given the clinical relevance of sodium mercaptoundecahydro-closo-dodecaborate (BSH) as a boron carrier, the aim of the present study was to expand the ongoing BSH biodistribution studies in the hamster cheek pouch oral cancer model. In particular, we studied 3 additional post-administration time-points and increased the sample size corresponding to the time-points evaluated previously, to select more accurately the post-administration time at which neutron irradiation would potentially confer the greatest therapeutic advantage. BSH was dissolved in saline solution in anaerobic conditions to avoid the formation of the dimer BSSB and its oxides which are toxic. The solution was injected intravenously at a dose of 50 mg 10 B/kg (88 mg BSH / kg). Different groups of animals were killed humanely at 7, 8, and 10 h after administration of BSH. The sample size corresponding to the time-points 3, 4, 6, 9 and 12 h was increased. Samples of blood, tumor, precancerous tissue, normal pouch tissue, cheek mucosa, parotid gland, palate, skin, tongue, spinal cord marrow, brain, liver, kidney, spleen and lung were processed for boron measurement by Optic Emission Spectroscopy (ICP-OES). Boron concentration in tumor peaked to 24-34 ppm, 3-10 h post-administration of BSH, with a spread in values that resembled that previously reported in other experimental models and human subjects. The boron concentration ratios tumor/normal pouch tissue and tumor/blood ranged from 1.3 to 1.8. No selective tumor uptake was observed at any of the time points evaluated. The times post-administration of BSH that would be therapeutically most useful would be 5, 7 and 9 h. The

  15. Quantifying the Solubility of Boron Nitride Nanotubes and Sheets with Static Light Scattering and Refractometry

    Energy Technology Data Exchange (ETDEWEB)

    Mutz, M [The University of Tennessee; Eastwood, Eric Allen [ORNL; Dadmun, Mark D [ORNL

    2013-01-01

    The dissolution of nanoparticles, particularly those containing boron, is an important area of interest for polymer nanocomposite formation and material development. In this work, the solubility of boron nitride nanotubes (BNNT), functionalized boron nitride nanotubes (FBNNT), and boron nitride sheets (BNZG) is quantified in toluene and THF with static light scattering, refractometry, UV vis spectroscopy, and physical observations. UV vis spectroscopy provides a method to determine the concentration and solubility limits of the solutions tested. Using light scattering, the second virial coefficient, A2, is determined and used to calculate , the solute solvent interaction parameter. The Hildebrand solubility parameter, , is then extracted from this data using the Hildebrand Scatchard Solution Theory. A list of potential good solvents based on the estimated value is provided for each nanoparticle. Single-walled carbon nanotubes (SWNTs) and prepolymers (EN4 and EN8) used to synthesize polyurethanes were also tested, because the published and molar attraction constants of these materials provided a selfconsistent check. The dn/dc of SWNTs and boron-containing particles was measured for the first time in this work. A solvent screen for BN-ZG provides additional information that supports the obtained and . Three systems were found to have values below 0.5 and were thermodynamically soluble: BNNT in THF, EN8 in THF, and EN8 in toluene.

  16. Burnup performances of boron nitride and boron coated nuclear fuels

    International Nuclear Information System (INIS)

    The nuclear fuels of urania (UOV) and 5% and 10% gadolinia (Gd2O3) containing UO2 previously produced by sol-gel technique were coated with first boron nitride (BN) then boron (B) thin layer by chemical vapor deposition (CVD) and also by plasma enhanced chemical vapor deposition (PECVD) techniques to increase the fuel cycle length and to improve the physical properties. From the cross-sectional view of BN and B layers taken from scanning electron microscope (SEM), the excellent adherence of BN onto fuel and B onto BN layer was observed in both cases. The behavior of fuel burnup, depletion of BN and B, the effect of coating thickness and also Gd2O3 content on the burnup performances of the fuels were identified by using the code WIMS-D/4 for Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) cores. The optimum thickness ratio of B to BN was found as 4 and their thicknesses were chosen as 40 mm and 10 mm respectively in both reactor types to get extended cycle length. The assemblies consisting of fuels with 5% Gd2O3 and also coated with 10 mm BN and 40 mm B layers were determined as candidates for getting higher burnup in both types of reactors

  17. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  18. Boron enrichment in martian clay.

    Science.gov (United States)

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  19. "Light-up" Sensing of human 8-oxoguanine DNA glycosylase activity by target-induced autocatalytic DNAzyme-generated rolling circle amplification.

    Science.gov (United States)

    Kong, Xiang-Juan; Wu, Shuang; Cen, Yao; Yu, Ru-Qin; Chu, Xia

    2016-05-15

    Human 8-oxoguanine DNA glycosylase (hOGG1) plays a crucial role in maintaining the genomic integrity of living organisms for its capability of repairing DNA oxidative damage. The expression level of hOGG1 is closely associated with many diseases including various kinds of cancers. In this study, a novel "light-up" sensor based on target-induced formation of 5' phosphorylated probe and autocatalytic DNAzyme-generated rolling circle amplification has been developed for highly sensitive human 8-oxoguanine DNA glycosylase (hOGG1) activity assay. The approach reaches detection limit as low as 0.001U/mL for hOGG1 via scarcely increased background signal and dual signal amplification strategy. To the best of our knowledge, it is one of the most sensitive methods for the detection of base excision repair enzyme. Moreover, the approach shows excellent specificity over other nonspecific enzymes would interfere with the assay and holds great promise for application in real sample analysis. Hence, the proposed method provides a highly sensitive, selective, and desirable hOGG1 sensing platform. PMID:26765532

  20. Design of a medical reactor generating high quality neutron beams for boron neutron capture therapy

    International Nuclear Information System (INIS)

    ) and a thermal neutron beam of 8.9x109nth/cm2 · s intensity with low contamination by fast neutrons (<1.1x10-13 Gy · cm2/nth) and gamma rays (<1.2x10-13 Gy · cm2/nth). Both neutron beams are highly forward-directed. Each beam can be turned on and off independently through its individual shutter. A complete BNCT treatment using the designed epithermal neutron beam would take 14 min under the condition of assuming 12.3 μg 10B/g in the blood. Such exposure times should be sufficiently short to maintain near-optimal target (e.g., 10B, 157Gd, 235U) distribution in tumor versus normal tissues throughout the irradiation. With a low operating power of 300kW, the heat generated in the core can be removed by natural convection through a pool of light water. The proposed design in this study could be constructed for a dedicated clinical BNCT facility that would operate very safely

  1. Avalanche proton-boron fusion based on elastic nuclear collisions

    Science.gov (United States)

    Eliezer, Shalom; Hora, Heinrich; Korn, Georg; Nissim, Noaz; Martinez Val, Josè Maria

    2016-05-01

    Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 109 alphas. We suggest that these unexpected very high fusion reactions of proton with 11B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-11B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

  2. Experimental boron neutron capture therapy for melanoma: Systemic delivery of boron to melanotic and amelanotic melanoma

    International Nuclear Information System (INIS)

    The boron-containing melanin precursor analogue p-boronophenylalanine (BPA) has previously been shown to selectively deliver boron to pigmented murine melanomas when administered in a single intragastric dose. If boron neutron capture therapy is to become a clinically useful method of radiation therapy for human malignant melanoma, the boron carrier must be capable of delivering useful amounts of boron to remote tumor sites (metastases) and to poorly pigmented melanomas. The authors have now determined the ability of BPA to accumulate in several nonpigmented melanoma models including human melanoma xenografts in nude mice. The absolute amount of boron in the nonpigmented melanomas was about 50% of the observed in the pigmented counterparts but was still selectively concentrated in the tumor relative to normal tissues in amounts sufficient for effective neutron capture therapy. Single intragastric doses of BPA resulted in selective localization of boron in the amelanotic Greene melanoma carried in the anterior chamber of the rabbit eye and in a pigmented murine melanoma growing in the lungs. The ratio of the boron concentration in these tumors to the boron concentration in the immediately adjacent normal tissue was in the range of 3:1 to 4:1. These distribution studies support the proposal that boron neutron capture therapy may be useful as a regional therapy for malignant melanoma

  3. The haloarchaeal MCM proteins: bioinformatic analysis and targeted mutagenesis of the β7-β8 and β9-β10 hairpin loops and conserved zinc binding domain cysteines

    Directory of Open Access Journals (Sweden)

    Tatjana P Kristensen

    2014-03-01

    Full Text Available The hexameric MCM complex is the catalytic core of the replicative helicase in eukaryotic and archaeal cells. Here we describe the first in vivo analysis of archaeal MCM protein structure and function relationships using the genetically tractable haloarchaeon Haloferax volcanii as a model system. Hfx. volcanii encodes a single MCM protein that is part of the previously identified core group of haloarchaeal MCM proteins. Three structural features of the N-terminal domain of the Hfx. volcanii MCM protein were targeted for mutagenesis: the β7-β8 and β9-β10 β-hairpin loops and putative zinc binding domain. Five strains carrying single point mutations in the β7-β8 β-hairpin loop were constructed, none of which displayed impaired cell growth under normal conditions or when treated with the DNA damaging agent mitomycin C. However, short sequence deletions within the β7-β8 β-hairpin were not tolerated and neither was replacement of the highly conserved residue glutamate 187 with alanine. Six strains carrying paired alanine substitutions within the β9-β10 β-hairpin loop were constructed, leading to the conclusion that no individual amino acid within that hairpin loop is absolutely required for MCM function, although one of the mutant strains displays greatly enhanced sensitivity to mitomycin C. Deletions of two or four amino acids from the β9-β10 β-hairpin were tolerated but mutants carrying larger deletions were inviable. Similarly, it was not possible to construct mutants in which any of the conserved zinc binding cysteines was replaced with alanine, underlining the likely importance of zinc binding for MCM function. The results of these studies demonstrate the feasibility of using Hfx. volcanii as a model system for reverse genetic analysis of archaeal MCM protein function and provide important confirmation of the in vivo importance of conserved structural features identified by previous bioinformatic, biochemical and structural

  4. New Pathways and Metrics for Enhanced, Reversible Hydrogen Storage in Boron-Doped Carbon Nanospaces

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Peter [University of Missouri; Wexler, Carlos [University of Missouri; Hawthorne, M. Frederick [University of Missouri; Lee, Mark W. [University of Missouri; Jalistegi, Satish S. [University of Missouri

    2014-08-14

    This project, since its start in 2007—entitled “Networks of boron-doped carbon nanopores for low-pressure reversible hydrogen storage” (2007-10) and “New pathways and metrics for enhanced, reversible hydrogen storage in boron-doped carbon nanospaces” (2010-13)—is in support of the DOE's National Hydrogen Storage Project, as part of the DOE Hydrogen and Fuel Cells Program’s comprehensive efforts to enable the widespread commercialization of hydrogen and fuel cell technologies in diverse sectors of the economy. Hydrogen storage is widely recognized as a critical enabling technology for the successful commercialization and market acceptance of hydrogen powered vehicles. Storing sufficient hydrogen on board a wide range of vehicle platforms, at energy densities comparable to gasoline, without compromising passenger or cargo space, remains an outstanding technical challenge. Of the main three thrust areas in 2007—metal hydrides, chemical hydrogen storage, and sorption-based hydrogen storage—sorption-based storage, i.e., storage of molecular hydrogen by adsorption on high-surface-area materials (carbons, metal-organic frameworks, and other porous organic networks), has emerged as the most promising path toward achieving the 2017 DOE storage targets of 0.055 kg H2/kg system (“5.5 wt%”) and 0.040 kg H2/liter system. The objective of the project is to develop high-surface-area carbon materials that are boron-doped by incorporation of boron into the carbon lattice at the outset, i.e., during the synthesis of the material. The rationale for boron-doping is the prediction that boron atoms in carbon will raise the binding energy of hydro- gen from 4-5 kJ/mol on the undoped surface to 10-14 kJ/mol on a doped surface, and accordingly the hydro- gen storage capacity of the material. The mechanism for the increase in binding energy is electron donation from H2 to electron-deficient B atoms, in the form of sp2 boron-carbon bonds. Our team is proud to have

  5. Recent results at the SIRa test bench: diffusion properties of carbon graphite and B4C targets

    International Nuclear Information System (INIS)

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for 6He (T1/2 = 806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B4C (Boron Carbide) have also been studied. Yields of 1.5 108 pps and 106 pps for 6He and 8He has been obtained. (authors)

  6. Medical aspects of boron-slow neutron capture therapy

    International Nuclear Information System (INIS)

    Earlier radiations of patients with cerebral tumors disclosed the need: (1) to find a carrier of the boron compound which would leave the blood and concentrate in the tumor, (2) to use a more penetrating neutron beam, and (3) to develop a much faster method for assaying boron in blood and tissue. To some extent number1 has been accomplished in the form of Na2 B12 H11 SH, number2 has yet to be achieved, and number3 has been solved by the measurement of the 478-keV gamma ray when the 10B atom disintegrates following its capture of a slow neutron. The hitherto unreported data in this paper describe through the courtesy of Professor Hiroshi Hatanaka his studies on the pharmacokinetics and quality control of Na2 B12 H11SH based on 96 boron infusions in 86 patients. Simultaneous blood and tumor data are plotted here for 30 patients with glioblastomas (Grade III-IV gliomas), illustrating remarkable variability. Detailed autopsy findings on 18 patients with BNCT showed radiation injury in only 1. Clinical results in 12 of the most favorably situated glioblastomas reveal that 5 are still alive with a 5-year survival rate of 58% and the excellent Karnofsky performance rating of 87%. For the first time evidence is presented that slow-growing astrocytomas may benefit from BNCT. 10 references, 8 figures, 5 tables

  7. Automatic spectrophotometric determination of trace amounts of boron with curcumin

    International Nuclear Information System (INIS)

    The proposed method utilizes a rosocyanin complex formed by the reaction of boric acid and curcumin without evaporation to dryness. The automatic determination of boron in aqueous solution is performed according to the predetermined program (Fig. 8), after manual injection of a sample solution (2.00 ml) to the reaction vessel. Glacial acetic acid (5.40 ml) and propionic anhydride (13.20 ml) are added and the solution is circulated through the circulating pipe consisting of a bubble remover, an absorbance measuring flow cell, an air blowing tube and a drain valve. Oxalyl chloride (0.81 ml) is added and the solution is circulated for 80 seconds to eliminate water. Sulfuric acid (1.08 ml) and curcumin reagent (3.01 ml) are added and the solution is circulated for 120 seconds to form a rosocyanin complex. After addition of an acetate buffer solution (21.34 ml) for the neutralisation of an interfering proton complex of curcumin, the absorbance of the orange solution is measured at 545 nm. This automatic analysis is sensitive (Fig. 9) and rapid; less than 1.5 μg of boron is determined in 7 minutes. It can be applied to the determination of trace amounts of boron in steel samples, combined with an automatic distillation under development. (auth.)

  8. Full-scale simulation of seawater reverse osmosis desalination processes for boron removal: Effect of membrane fouling.

    Science.gov (United States)

    Park, Pyung-Kyu; Lee, Sangho; Cho, Jae-Seok; Kim, Jae-Hong

    2012-08-01

    The objective of this study is to further develop previously reported mechanistic predictive model that simulates boron removal in full-scale seawater reverse osmosis (RO) desalination processes to take into account the effect of membrane fouling. Decrease of boron removal and reduction in water production rate by membrane fouling due to enhanced concentration polarization were simulated as a decrease in solute mass transfer coefficient in boundary layer on membrane surface. Various design and operating options under fouling condition were examined including single- versus double-pass configurations, different number of RO elements per vessel, use of RO membranes with enhanced boron rejection, and pH adjustment. These options were quantitatively compared by normalizing the performance of the system in terms of E(min), the minimum energy costs per product water. Simulation results suggested that most viable options to enhance boron rejection among those tested in this study include: i) minimizing fouling, ii) exchanging the existing SWRO elements to boron-specific ones, and iii) increasing pH in the second pass. The model developed in this study is expected to help design and optimization of the RO processes to achieve the target boron removal at target water recovery under realistic conditions where membrane fouling occurs during operation. PMID:22578430

  9. Delamination of hexagonal boron nitride in a stirred media mill

    International Nuclear Information System (INIS)

    A scalable process for delamination of hexagonal boron nitride in an aqueous solution of the non-ionic surfactant TWEEN85 using a stirred media mill is presented. The size of the ZrO2 beads used as grinding media governs the dimensions of the ground boron nitride particles as atomic force microscopic investigations (AFM) reveal: the mean flakes thickness decreases from 3.5 to 1.5 nm and the ratio between mean flake area and mean flake thickness increases from 2,200 to 5,800 nm if the grinding media size is reduced from 0.8 to 0.1 mm. This result shows that a high number of stress events in combination with low stress energy (small grinding media) facilitate delamination of the layered material whereas at high stress energies in combination with a low number of stress events (large grinding media) breakage of the layers dominates over delamination. The results of particle height analyses by AFM show that few-layer structures have been formed by stirred media milling. This result is in agreement with the layer thickness dependence of the delamination energy for hexagonal boron nitride. The concentration of nanoparticles remaining dispersed after centrifugation of the ground suspension increases with grinding time and with decreasing grinding media size. After 5 h of grinding using 0.1 mm ZrO2 grinding media the yield of nanoparticle formation is about 5 wt%. The nanoparticles exhibit the typical Raman peak for hexagonal boron nitride at 1,366 cm−1 showing that the in-plane order in the milled platelets is remained.

  10. Studies of boron hydrides: new heteroboranes

    International Nuclear Information System (INIS)

    I. The chemistry of the bipentaborane 2,2'-(B5H8)2 is investigated to some extent. Pyrolysis of 2,2'-(B5H8)2 resulted in the formation of non-volatile solid boron hydrides and hydrogen. Treatment of 2,2'-(B5H8)2 with bromine in the presence of AlBr3 resulted in the isolation of 1,1'Br2-2,2'-(B5H7)2. Reaction of 2,2'-(B5H8)2 with deprotonating agents resulted in the formation of the corresponding anions. Reaction of 2,2'-(B5H8)2 with diborane followed by acidification afforded n-B9H15 and B10H14 in moderate yield. II. Reaction of K+B9H12S- with potassium polyselenide resulted in the isolation of stable white crystals of B9H9SSe. Treatment of B9H9SSe with one equivalent of base in methanol gave the unstable heteroborane B8H9(OCH3)SSE and treatment with two equivalents of base afforded yellow crystals of B7H9SSe. Reaction of K+B9H12S- with arsenic trioxide in aqueous basic solution gave the electron-rich heteroborane, B8H8As2S in moderate yield. This resulted in the isolation and identification of Et3N.BH3 and the new metalloborane B7H7As2SCo(C5H5). Treatment of B10H11Se- with As2O3 resulted in the isolation of the stable nido-heteroborane B8H8As2Se in low yield. Reaction of B7C2H13 with potassium polyselenide gave the arachno selenacarborane B7H2C11Se in low yield. The structure of the new heteroborane is proposed on the basis of 11B and 1H nmr spectra. Reaction of B7C2H13 with AsCl3 resulted in the isolation of white stable crystals of B7C2H9As2 in 40 percent yield

  11. Colorimetric Sugar Sensing Using Boronic Acid-Substituted Azobenzenes

    OpenAIRE

    Yuya Egawa; Ryotaro Miki; Toshinobu Seki

    2014-01-01

    In association with increasing diabetes prevalence, it is desirable to develop new glucose sensing systems with low cost, ease of use, high stability and good portability. Boronic acid is one of the potential candidates for a future alternative to enzyme-based glucose sensors. Boronic acid derivatives have been widely used for the sugar recognition motif, because boronic acids bind adjacent diols to form cyclic boronate esters. In order to develop colorimetric sugar sensors, boronic acid-conj...

  12. Synthesis and characterization of ammonium phosphate fertilizers with boron

    OpenAIRE

    ANGELA MAGDA; RODICA PODE; CORNELIA MUNTEAN; MIHAI MEDELEANU; ALEXANDRU POPA

    2010-01-01

    The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the ...

  13. Effects of Boron Purity, Mg Stoichiometry and Carbon Substitution on Properties of Polycrystalline MgB$_{2}$

    OpenAIRE

    R.A. Ribeiro; Bud'ko, S. L.; Petrovic, C.; Canfield, P. C.

    2002-01-01

    By synthesizing MgB$_{2}$ using boron of different nominal purity we found values of the residual resistivity ratio ($RRR = R(300 K) / R(42 K)$) from 4 to 20, which covers almost all values found in literature. To obtain high values of $RRR$, high purity reagents are necessary. With the isotopically pure boron we obtained the highest $RRR \\sim$ 20 for the stoichiometric compound. We also investigated Mg$_{x}$$^{11}$B$_{2}$ samples with 0.8 $< x

  14. The determination of boron and carbon in reactor grade boron carbide

    International Nuclear Information System (INIS)

    The sealed tube method of dissolution at high temperature and pressure has been successfully applied in the analysis of reactor grade boron carbide for the determination of boron. A 50 mg sample of boron carbide is completely dissolved by heating with concentrated nitric acid in a sealed tube at 3000C. The boron content of the resultant sample solution is determined by the mannitol potentiometric titration method. The precision of the method for the determination of 2.5 mg of boron using the Harwell automatic potentiometric titrator is 0.2% (coefficient of variation). The carbon content of a boron carbide sample is determined by combustion of the sample at 10500C in a stream of oxygen using vanadium pentoxide to ensure the complete oxidation of the sample. The carbon dioxide produced from the sample is measured manometrically and the precision of the method for the determination of 4 mg of carbon is 0.4% (coefficient of variation). (author)

  15. Proceedings of workshop on 'Boron Chemistry and Boron Neutron Capture Therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the 3rd Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 12, in 1991. In this workshop, our attention was focused on the chemical nature of boron compounds and the boron neutron capture therapy (BNCT). First, clinical experiences of BNCT in KURRI in 1990 and 1991 were reported (Chap. 3). The feasibility of the gadolinium neutron capture therapy for brain tumors was discussed (Chap. 4). In the chemical field, a rapid spectrophotometric determination of trace amounts of borons in biological samples is described (Chap. 5). The chemical behaviours of p-boronophenylalanine and its analogs in aqueous solutions were investigated by a paper electrophoresis and infrared spectroscopy (Chap. 6). On the molecular design and synthesis of new boron carriers for BNCT, several new synthetic methods for B-10 containing nucleoside derivatives were shown (Chap. 7). (author)

  16. Quantitative boron detection by neutron transmission method

    International Nuclear Information System (INIS)

    //Quantitative boron detection is mainly performed by chemical methods like colorimetric titration. High neutron absorption cross section of natural boron makes attractive its detection by absorption measurements. This work is an extension of earlier investigations where neutron radiography technique was used for boron detection. In the present investigation, the neutron absorption rate of boron containing solutions is the way to measure quantitatively the boron content of the solutions. The investigation was carried out in Istanbul TRIGA Mark-II reactor. In the end of the experiments, it was observed that even |ppw| grade boron in aqueous solution can be easily detected. The use of this method is certainly very useful for boron utilizing industries like glass and steel industries.The major disadvantage of the method is the obligation to use always aqueous solutions to be able to detect homogeneously the boron content. Then, steel or glass samples have to be put first in an appropriate solution form. The irradiation of steel samples can give the distribution of boron by the help of a imaging and this suggested method will give its quantitative measurement. The superiority of this method are its quick response time and its accuracy. To test this accuracy, a supposed unknown , solution of boric acid is irradiated and then calculated by the help of the calibration curve. The measured value of boric acid was 0.89 mg and the calculated value was found to be 0.98 mg which gives an accuracy of 10 %. It was also seen that the method is more accurate for low concentration. (authors)

  17. Plasma deposition of boron films with high growth rate and efficiency using carborane

    International Nuclear Information System (INIS)

    The injection of carborane (C2B10H12) on the PISCES-B linear plasma device has been used to produce boron containing films on various target species. Film growth rates achieved are extremely high (up to 30 nm/s) compared to those typically found for glow discharges (∼0.01 nm/s). For low-Z target materials (C and Al) the film production is highly efficient, with the boron film growth rate comparable to the incident ion flux and the injection rate of boron atoms. The boron to carbon ratio is 3.0-3.6 for these films. Similarly high growth rates (∼10 nm/s) are obtained with high-Z target (W), but with lower deposition efficiency and higher B/C film ratio. The high film growth rate/efficiency are apparently linked to the high degree of carborane ionization and dissociation caused by the ∼40 eV PISCES-B plasma, compared with T<1 eV plasmas of glow discharges. This technique opens the possibility of continuously producing protective B films in thermonuclear devices where net erosion rates approach 10 nm/s

  18. Application of the boron neutron capture therapy to undifferentiated thyroid cancer using two boron compounds (BPA and BOPP)

    International Nuclear Information System (INIS)

    We have shown the selective uptake of boronophenylalanine (BPA) by undifferentiated thyroid cancer (UTC) human cell line ARO, both in vitro and in vivo. Moreover, a 50% histologic cure of mice bearing the tumor was observed when the complete boron neutron capture therapy was applied. More recently we have analyzed the biodistribution of BOPP (tetrakis-carborane carboxylate ester of 2,4-bis-(ba-dihydroxyethyl)-deutero-porphyrin IX) and showed that when BOPP was injected 5 days before BPA, and the animals were sacrificed 60 min after the ip injection of BPA, a significant increase in boron uptake by the tumor was found (38-45ppm with both compounds Vs. 20 ppm with BPA alone). Five days post the ip BOPP injection and 1 hr after BPA, the ratios were: tumor/blood 3,75; tumor /distal skin 2. Other important ratios were tumor/thyroid 6,65 and tumor/lung 3,8. The present studies were performed in mice transplanted with ARO cells and injected with BOPP and BPA. Only in mice treated with the neutron beam and injected with the boronated compounds we observed a 100% control of tumor growth. Two groups of mice received different total absorbed doses: 3.00 and 6.01 Gy, but no further improvement in the outcome was found compared to the previous results using BPA alone (4.3 Gy). (author)

  19. X-ray diffraction study of boron produced by pyrolysis of boron tribromide

    Science.gov (United States)

    Rosenberg, David

    The goal of this research was to determine the composition of boron deposits produced by pyrolysis of boron tribromide, and to use the results to (a) determine the experimental conditions (reaction temperature, etc.) necessary to produce alpha-rhombohedral boron and (b) guide the development/refinement of the pyrolysis experiments such that large, high purity crystals of alpha-rhombohedral boron can be produced with consistency. Developing a method for producing large, high purity alpha-rhombohedral boron crystals is of interest because such crystals could potentially be used to achieve an alpha-rhombohedral boron based neutron detector design (a solid-state detector) that could serve as an alternative to existing neutron detector technologies. The supply of neutron detectors in the United States has been hampered for a number of years due to the current shortage of helium-3 (a gas used in many existing neutron detector technologies); the development of alternative neutron detector technology such as an alpha-rhombohedral boron based detector would help provide a more sustainable supply of neutron detectors in this country. In addition, the prospect/concept of an alpha-rhombohedral boron based neutron detector is attractive because it offers the possibility of achieving a design that is smaller, longer life, less power consuming, and potentially more sensitive than existing neutron detectors. The main difficulty associated with creating an alpha-rhombohedral boron based neutron detector is that producing large, high purity crystals of alpha-rhombohedral boron is extremely challenging. Past researchers have successfully made alpha-rhombohedral boron via a number of methods, but no one has developed a method for consistently producing large, high purity crystals. Alpha-rhombohedral boron is difficult to make because it is only stable at temperatures below around 1100-1200 °C, its formation is very sensitive to impurities, and the conditions necessary for its

  20. Sintering of boron carbide (B4C)

    International Nuclear Information System (INIS)

    Boron carbide (B4C) is used as a control element in different types of reactors due to the high fast and thermal neutron absorption cross-section of B-10. Requirements of the Advanced Reactor Division of the Bariloche Atomic Center triggered the study of the possibilities of fabricating B4C pellets by cold-pressing and sintering. The results of essays of sinterability of two different commercial boron carbide powders, sintered at temperatures between 1200 and 2200 deg C, are given. Characterizations of the samples were made to determine the evolution of density, porosity, microstructure and boron content as a function of sintering temperature. (Author)

  1. Developments in boron magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  2. First boronization in KSTAR: Experiences on carborane

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Suk-Ho, E-mail: sukhhong@nfri.re.kr [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Kun-Su; Kim, Kwang-Pyo; Kim, Kyung-Min; Kim, Hong-Tack [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Sun, Jong-Ho; Woo, Hyun-Jong [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Jae-Min [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Park, Eun-Kyong [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Woong-Chae; Kim, Hak-Kun; Park, Kap-Rai; Yang, Hyung-Lyeol; Oh, Yeong-Kook; Na, Hoon-Kyun [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Lho, Taehyeop [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Chung, Kyu-Sun [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-08-01

    First boronization was performed in KSTAR tokamak during 2009 campaign in order to reduce oxygen impurities and to lower the power loss due to radiation. We report the results from the experiences on carborane during the first boronization in KSTAR. After the boronization, H{sub 2}O and O{sub 2} level in the vacuum vessel are reduced significantly. The characteristics of the deposited thin films were analyzed by variable angle spectroscopic ellipsometry, XPS, and AES. {approx}1.78 x 10{sup 16} cm{sup -2} s{sup -1} of carbon flux on the wall is estimated by using cavity technique.

  3. Synthesis of Boron Nanorods by Smelting Non-Toxic Boron Oxide in Liquid Lithium

    OpenAIRE

    Amartya Chakrabarti; Tao Xu; Laura K. Paulson; Krise, Kate J.; Maguire, John A; Hosmane, Narayan S.

    2010-01-01

    In contrast to the conventional bottom-up syntheses of boron nanostructures, a unique top-down and greener synthetic strategy is presented for boron nanorods involving nontoxic boron oxide powders ultrasonically smelted in liquid lithium under milder conditions. The product was thoroughly characterized by energy dispersive X-ray analysis, atomic emission spectroscopy, thermogravimetric analysis and, UV-Vis spectroscopy, including structural characterization by transmission electron microscop...

  4. Determination of boron isotope ratios in boron carbide by mass spectrometry

    International Nuclear Information System (INIS)

    This paper introduces the direct determination of boron isotope ratios in the boron carbide powder by thermal ionization mass spectrometry. The technique for sample loading, the procedure for heating and the eliminating of effects induced by oxygen are studied. The study indicates that the preparing process for the sample will be shorted, and the time for determination and the exposure dose of the laboratory assistant will be reduced for the reason of directly determination of boron carbide. (authors)

  5. Effect of boron concentration on physicochemical properties of boron-doped carbon nanotubes

    International Nuclear Information System (INIS)

    Boron-doped carbon nanotubes (B-CNTs) were synthesized using chemical vapour deposition (CVD) floating catalyst method. Toluene was used as the carbon source, triphenylborane as boron as well as the carbon source while ferrocene was used as the catalyst. The amount of triphenylborane used was varied in a solution of toluene and ferrocene. Ferrocene was kept constant at 2.5 wt.%. while a maximum temperature of 900 °C was used for the synthesis of the shaped carbon nanomaterial (SCNMs). SCNMs obtained were characterized by the use of transmission electron microscope (TEM), scanning electron microscope (SEM), high resolution-electron microscope, electron dispersive X-ay spectroscopy (EDX), Raman spectroscopy, inductively coupled plasma-optical emission spectroscopy (ICP-OES), vibrating sample magnetometer (VSM), nitrogen adsorption at 77 K, and inverse gas chromatography. TEM and SEM analysis confirmed SCNMs obtained were a mixture of B-CNTs and carbon nanofibres (B-CNF). EDX and ICP-OES results showed that boron was successively incorporated into the carbon hexagonal network of CNTs and its concentration was dependent on the amount of triphenylborane used. From the VSM results, the boron doping within the CNTs introduced ferromagnetic properties, and as the percentage of boron increased the magnetic coactivity and squareness changed. In addition, boron doping changed the conductivity and the surface energy among other physicochemical properties of B-CNTs. - Highlights: • Boron-doping of carbon nanotubes (CNTs) changes their physiochemical properties. • Amount of boron-doping was dependent on the wt.% of boron precursor used. • Boron-doping changed CNTs surfaces and the distribution of dispersive energy sites. • Boron-doping affected the conductivity and ferromagnetic properties. • Increased boron-doping results in a more favourable interaction with polar probes

  6. Engineering design feasibility of low boron concentration core in PWR

    International Nuclear Information System (INIS)

    In pressurized water reactor operation, higher level of soluble boron concentration could contribute higher impact from boron dilution situations, higher amount of liquid waste, and higher radiation dose to operators from higher corrosion potential to cladding and structure. Two practical and feasible means to reduce the maximum boron concentration were investigated in this study. A technically straightforward, possible means, can be achieved either by implementation of enriched boric acid (Eba) or by increasing more shim rod (fixed burnable absorber) worth. A simplest option is that the Eba is applied into reference core (Ref) design, OPR-1000 design, Ulchin unit-5 by allowing use of same fuel assemblies and core design without changing any nuclear design methodology used in that Ref design. Although results of Eba option proved its favorable power distribution and peaking factor, its moderator temperature coefficient (MTC) value reached positive, 3.25 pcm/ C at 40 EFPD which is beyond the design safety limit. An alternative option with more shim rods in fuel assemblies was tried with four types of integral burnable absorbers: gadolinia, integral fuel burnable absorber (Ifba), erbium and alumina boron carbide. Four core design candidates have been developed by keeping major engineering designs and preserving equivalent fuel enrichment level used in Ref design. However, all optimal designs were targeted to achieve comparable discharge burnup as well as favorable design safety parameters. The comparative analysis between Ref and optimal core designs is presented here. One of them is suggested as the most promising and favorable low boron core (Lbc) design in this framework. The proper combination of axial and radial enrichment zoning pattern in Lbc design candidate with Ifba-bearing fuel assemblies at equilibrium cycle, could bring 2 times narrower axial offset variation than that of Ref design, and maintain acceptable power peaking factor around 23% lower than

  7. Investigation of boron extraction process with aid magnesium hydroxide from mother liquor of boron production

    International Nuclear Information System (INIS)

    Conditions of boron - magnesium concentrate preparation from mother liquor by coprecipitation of borate - ions by magnesium hydroxide are investigated. It is shown that boron - magnesium concentrate and products of its heat treatment at 100 - 500 deg C in water are dissolved partially, and in ammonium citrate - practically completely. Suppositions are made on the composition of the product prepared, on the the structure of its crystal lattice and the processes taking place in it during heat treatment. The conclusion is made on the perspectiveness of processing of mother liquor of boron industry for boron - magnesium concentrate

  8. Boron

    International Nuclear Information System (INIS)

    This paper reports that borate minerals and refined borates are used extensively for the manufacture of vitreous materials such as insulation and textile fiberglasses, borosilicate glass, and porcelain enamels and frits. In North America, these applications are estimated to account for over 54% of the borate consumption. Other substantial uses are in soaps and detergents, metallurgy, fire retardants, industrial biocides, agriculture, and various miscellaneous applications. Reported domestic borate consumption in 1990 was estimated by the U.S. Bureau of Mines to be 320 000 metric tons B2O3 versus 354 000 metric tons B2O3 in 1989. Consumption is projected to remain essentially static in 1991. Imports were estimated by the Bureau to be 50 000 metric tons B2O3 in 1990. Exports of boric acid and refined borates were approximately 650 000 metric tons of product, a 15 000 metric ton increase from the 1989 level. This increase partially offsets the drop in the 1990 consumption level

  9. Study of the roles of chemical modifiers in determining boron using graphite furnace atomic absorption spectrometry and optimization of the temperature profile during atomization

    International Nuclear Information System (INIS)

    The measurement conditions for determining boron using graphite furnace–atomic absorption spectrometry (GF-AAS) were investigated. Differences in the boron absorbance profiles were found using three different commercially available GF-AAS instruments when the graphite atomizers in them were not tuned. The boron absorbances found with and without adjusting the graphite atomizers suggested that achieving an adequate absorbance for the determination of boron requires a sharp temperature profile that overshoots the target temperature during the atomization process. Chemical modifiers that could improve the boron absorbance without the need for using coating agents were tested. Calcium carbonate improved the boron absorbance but did not suppress variability in the peak height. Improvement of boron absorbance was comparatively less using iron nitrate or copper nitrate than using calcium carbonate, but variability in the peak height was clearly suppressed using iron nitrate or copper nitrate. The limit of detection was 0.0026 mg L−1 when iron nitrate was used. It appears that iron nitrate is a useful new chemical modifier for the quick and simple determination of boron using GF-AAS. (author)

  10. Boron-isotope fractionation in plants

    International Nuclear Information System (INIS)

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, 11B and 10B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in 11B relative to the nutrient solution, and the leaves were enriched in 10B and the stem in 11B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  11. Synthesis of Boron-Containing Primary Amines

    Directory of Open Access Journals (Sweden)

    Sheng-Hsuan Chung

    2013-10-01

    Full Text Available In this study, boron-containing primary amines were synthesized for use as building blocks in the study of peptoids. In the first step, Gabriel synthesis conditions were modified to enable the construction of seven different aminomethylphenyl boronate esters in good to excellent yields. These compounds were further utilized to build peptoid analogs via an Ugi four-component reaction (Ugi-4CR under microwave irradiation. The prepared Ugi-4CR boronate esters were then successfully converted to the corresponding boronic acids. Finally, the peptoid structures were successfully modified by cross-coupling to aryl/heteroaryl chlorides via a palladium-mediated Suzuki coupling reaction to yield the corresponding derivatives in moderate to good yields.

  12. Boron toxicity in oil palm (Elaeis guineensis)

    Energy Technology Data Exchange (ETDEWEB)

    Rajaratnam, J.A.

    1973-01-01

    Potted oil palms were treated with fertilizer of borate-46 at several concentrations and the plants were observed for boron toxicity effects. Toxicity symptoms were apparent at high rates but not at rates equivalent to typical Malaysian soils.

  13. Boron adsorption on hematite and clinoptilolite

    International Nuclear Information System (INIS)

    This thesis describes experiments performed to determine the suitability of boron as a potential reactive tracer for use in saturated-zone C-well reactive tracer studies for the Yucca Mountain Project (YMP). Experiments were performed to identify the prevalent sorption mechanism of boron and to determine adsorption of boron on hematite and clinoptilolite as a function of pH. These minerals are present in the Yucca Mountain tuff in which the C-well studies will be conducted. Evaluation of this sorption mechanism was done by determining the equilibration time of boron-mineral suspensions, by measuring changes in equilibrium to titrations, and by measuring electrophoretic mobility. Experiments were performed with the minerals suspended in NaCl electrolytes of concentrations ranging from 0.1 N NaCl to 0.001 N NaCl. Experimentalconditions included pH values between 3 and 12 and temperature of about 38 degrees C

  14. Boron-Filled Hybrid Carbon Nanotubes.

    Science.gov (United States)

    Patel, Rajen B; Chou, Tsengming; Kanwal, Alokik; Apigo, David J; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-01-01

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs. PMID:27460526

  15. Boron neutron capture therapy. What is next?

    International Nuclear Information System (INIS)

    BNCT (Boron Neutron Capture Therapy) will have difficulties establishing itself without efficient and conclusive clinical trials of glioma, without the expansion to other tumors, and without efficient programs for compound development and testing. (author)

  16. Ni doping of semiconducting boron carbide

    International Nuclear Information System (INIS)

    The wide band gap, temperature stability, high resistivity, and robustness of semiconducting boron carbide make it an attractive material for device applications. Undoped boron carbide is p type; Ni acts as a n-type dopant. Here we present the results of controlled doping of boron carbide with Ni on thin film samples grown using plasma enhanced chemical vapor deposition. The change in the dopant concentration within the thin film as a function of the dopant flow rate in the precursor gas mixture was confirmed by x-ray photoelectron spectroscopy measurements; with increasing dopant concentration, current-voltage (I-V) curves clearly establish the trend from p-type to n-type boron carbide.

  17. Analysis of boron at Koeberg Power Station

    International Nuclear Information System (INIS)

    Soluble reactivity poisons, also called chemical shim, produce spatially uniform neutron absorption when dissolved in reactor coolant water. The boron-10 isotope having a high neutron absorption coefficient is used in commercial pressurised water reactors (PWR) to limit and control reactivity. This is achieved at Koeberg Nuclear Power Station (KNPS) and the majority of commercial PWR's worldwide by the addition of natural boric acid to the reactor coolant. The boric acid dissolved in the coolant decreases the thermal utilisation factor, causing a decrease in reactivity. By varying the concentration of boric acid (and hence also the B-10 concentration) in the coolant, a process referred to as boration and dilution, the reactivity of the core can be easily managed. An increase in boron concentration (boration) creates negative reactivity and if the boron concentration is reduced (dilution), positive reactivity is added. The changing of boron concentration in a PWR is used primarily to compensate for fuel burn-up or poison build-up. The variation in boron concentration allows control rod use to be minimised, which results in a flatter flux profile over the core than can be produced by control rod manipulation. Accurate laboratory and on-line chemical analysis of boron concentration is important because of its operational implications associated with reactivity control and also for nuclear safety. In a normal fuel cycle, as the nuclear fuel is being consumed, the reactor coolant boric acid (B-10) concentration must be reduced by dilution with purified water to maintain the reactor at constant power. Besides in the reactor coolant water, boric acid concentration is also important in the chemical and volume control system and reactor make-up system for operation. For nuclear safety, boric acid concentrations are technical specification parameters, maintained and monitored in the spent fuel system and safety injection systems. Boron concentration determination is

  18. High temperature thermoelectric properties of boron carbide

    International Nuclear Information System (INIS)

    Boron carbides are refractory solids with potential for application as very high temperature p-type thermoelectrics in power conversion applications. The thermoelectric properties of boron carbides are unconventional. In particular, the electrical conductivity is consistent with the thermally activated hopping of a high density (∼1021/cm3) of bipolarons; the Seebeck coefficient is anomalously large and increases with increasing temperature; and the thermal conductivity is surprisingly low. In this paper, these unusual properties and their relationship to the unusual structure and bonding present in boron carbides are reviewed. Finally, the potential for utilization of boron carbides at very high temperatures (up to 2200 degrees C) and for preparing n-type materials is discussed

  19. Systematic study of the electronic structure and optical properties of icosahedral boron and boron compounds

    Science.gov (United States)

    Li, Dong

    1997-11-01

    A systematic study of the electronic structures, total energies and optical properties of B12-based boron and boron-rich compounds and boron oxide compounds has been conducted by the first-principles orthogonalized linear combination of atomic orbitals method. The materials involved are: α-r-B12, B12As2,/ B12P2,/ B11C(CBC)/ (or/ B4C),/ B13C2,/ B12O2,/ (B10Si2)Si2,/ (B10Si2)Si2-I, B2O3-I and B2O3-II. The band structures show that α-r-B12,/ B12As2,/ B12P2,/ B11C(CBC),/ B12O2,/ (B10Si2)Si2, and (B10Si2)Si2-I are semiconductors with band gaps ranging from 1.29 eV to 3.04 eV while B13C2 is a metal with an intrinsic hole at the top of the valence band below a semiconductor-like gap. The study also shows that B2O3-I and B2O3-II are wide gap insulators with calculated LDA gaps of 6.20 eV and 8.85 eV separately. The calculated density of states are resolved into atomic and orbital partial components and the valence-charge distributions are also studied. The natural bonding characteristics in these crystals are illuminated by evaluating the Mulliken effective charges on each atom and overlap populations between pairs of atoms. It is shown that inter-icosahedral bonding is much stronger than the intra-icosahedral bonding in the B12- based crystals. The chain elements in B12As2,/ B12P2,/ (B10Si2)Si2 and (B10Si2)Si2-I donate electrons to the icosahedra, while B11C(CBC),/ B13C2 and B12O2 gain a slight amount of charge in forming strong covalent bonds. For boron oxide compounds, B2O3-II is found to be more ionic than B2O3-I. It is also concluded that the sp2 planar bonding in B2O3-I is stronger than the sp3 tetrahedral bonding in B2O3-II. The bulk moduli of α-r-B12,/ B12As2,/ B12P2,/ B11C(CBC),/ B13C2 and B12O2 are estimated by means of total energy calculation as a function of crystal volume, and are to be considered as upper limits. We have also calculated the interband optical conductivities and the complex dielectric functions. Static dielectric constants for icosahedral

  20. Lithium-Beryllium-Boron : Origin and Evolution

    OpenAIRE

    Vangioni-Flam, Elisabeth; Casse, Michel; Audouze, Jean

    1999-01-01

    The origin and evolution of Lithium-Beryllium-Boron is a crossing point between different astrophysical fields : optical and gamma spectroscopy, non thermal nucleosynthesis, Big Bang and stellar nucleosynthesis and finally galactic evolution. We describe the production and the evolution of Lithium-Beryllium-Boron from Big Bang up to now through the interaction of the Standard Galactic Cosmic Rays with the interstellar medium, supernova neutrino spallation and a low energy component related to...

  1. Innovative boron nitride-doped propellants

    OpenAIRE

    Thelma Manning; Richard Field; Kenneth Klingaman; Michael Fair; John Bolognini; Robin Crownover; Carlton P. Adam; Viral Panchal; Eugene Rozumov; Henry Grau; Paul Matter; Michael Beachy; Christopher Holt; Samuel Sopok

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower ...

  2. A neutron diffraction study of amorphous boron

    Science.gov (United States)

    Delaplane, R. G.; Lundström, T.; Dahlborg, U.; Howells, W. S.

    1991-07-01

    The structure of amorphous boron has been studied with pulsed neutron diffraction techniques using the ISIS facilities at the Rutherford Appleton Laboratory. The experimental static structure factor S(Q) and radial distribution function support a structural model based on units of B12 icosahedra resembling those found in crystalline β-rhombohedral boron, but with a certain degree of disorder occurring in the linking between these subunits.

  3. Radiological analysis of plutonium glass batches with natural/enriched boron

    International Nuclear Information System (INIS)

    The disposition of surplus plutonium inventories by the US Department of Energy (DOE) includes the immobilization of certain plutonium materials in a borosilicate glass matrix, also referred to as vitrification. This paper addresses source terms of plutonium masses immobilized in a borosilicate glass matrix where the glass components include both natural boron and enriched boron. The calculated source terms pertain to neutron and gamma source strength (particles per second), and source spectrum changes. The calculated source terms corresponding to natural boron and enriched boron are compared to determine the benefits (decrease in radiation source terms) for to the use of enriched boron. The analysis of plutonium glass source terms shows that a large component of the neutron source terms is due to (a, n) reactions. The Americium-241 and plutonium present in the glass emit alpha particles (a). These alpha particles interact with low-Z nuclides like B-11, B-10, and O-17 in the glass to produce neutrons. The low-Z nuclides are referred to as target particles. The reference glass contains 9.4 wt percent B2O3. Boron-11 was found to strongly support the (a, n) reactions in the glass matrix. B-11 has a natural abundance of over 80 percent. The (a, n) reaction rates for B-10 are lower than for B-11 and the analysis shows that the plutonium glass neutron source terms can be reduced by artificially enriching natural boron with B-10. The natural abundance of B-10 is 19.9 percent. Boron enriched to 96-wt percent B-10 or above can be obtained commercially. Since lower source terms imply lower dose rates to radiation workers handling the plutonium glass materials, it is important to know the achievable decrease in source terms as a result of boron enrichment. Plutonium materials are normally handled in glove boxes with shielded glass windows and the work entails both extremity and whole-body exposures. Lowering the source terms of the plutonium batches will make the handling of

  4. Discharge cleaning on TFTR after boronization

    International Nuclear Information System (INIS)

    At the beginning of the 1990 TFTR experimental run, after replacement of POCO-AXF-5Q graphite tiles on the midplane of the bumper limiter by carbon fiber composite (CFC) tiles and prior to any Pulse Discharge Cleaning (PDC), boronization was performed. Boronization is the deposition of a layer of boron and carbon on the vacuum vessel inner surface by a glow discharge in a diborane, methane and helium mixture. The amount of discharge cleaning required after boronization was substantially reduced compared to that which was needed after previous openings when boronization was not done. Previously, after a major shutdown, about 105 low current (∼20 kA) Taylor Discharge Cleaning (TDC) pulses were required before high current (∼400 kA) aggressive Pulse Discharge Cleaning (PDC) pulses could be performed successfully. Aggressive PDC is used to heat the limiters from the vessel bakeout temperature of 150 degrees C to 250 degrees C for a period of several hours. Heating the limiters is important to increase the rate at which water is removed from the carbon limiter tiles. After boronization, the number of required TDC pulses was reduced to <5000. The number of aggressive PDC pulses required was approximately unchanged. 14 refs., 1 tab

  5. Amorphous boron nitride at high pressure

    Science.gov (United States)

    Durandurdu, Murat

    2016-06-01

    The pressure-induced phase transformation in hexagonal boron nitrite and amorphous boron nitrite is studied using ab initio molecular dynamics simulations. The hexagonal-to-wurtzite phase transformation is successfully reproduced in the simulation with a transformation mechanism similar to one suggested in experiment. Amorphous boron nitrite, on the other hand, gradually transforms to a high-density amorphous phase with the application of pressure. This phase transformation is irreversible because a densified amorphous state having both sp3 and sp2 bonds is recovered upon pressure release. The high-density amorphous state mainly consists of sp3 bonds and its local structure is quite similar to recently proposed intermediate boron nitrite phases, in particular tetragonal structure (P42/mnm), rather than the known the wurtzite or cubic boron nitrite due to the existence of four membered rings and edge sharing connectivity. On the basis of this finding we propose that amorphous boron nitrite might be best candidate as a starting structure to synthesize the intermediate phase(s) at high pressure and temperature (probably below 800 °C) conditions.

  6. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  7. Innovative boron nitride-doped propellants

    Institute of Scientific and Technical Information of China (English)

    Thelma MANNING; Henry GRAU; Paul MATTER; Michael BEACHY; Christopher HOLT; Samuel SOPOK; Richard FIELD; Kenneth KLINGAMAN; Michael FAIR; John BOLOGNINI; Robin CROWNOVER; Carlton P. ADAM; Viral PANCHAL; Eugene ROZUMOV

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  8. Boronization of Russian tokamaks from carborane precursors

    International Nuclear Information System (INIS)

    A new and cheap boronization technique using the nontoxic and nonexplosive solid substance carborane has been developed and successfully applied to the Russian tokamaks T-11M, T-3M, T-10 and TUMAN-3. The glow discharge in a mixture of He and carborane vapor produced the amorphous B/C coating with the B/C ratio varied from 2.0-3.7. The deposition rate was about 150 nm/h. The primary effect of boronization was a significant reduction of the impurity influx and the plasma impurity contamination, a sharp decrease of the plasma radiated power, and a decrease of the effective charge. Boronization strongly suppressed the impurity influx caused by additional plasma heating. ECR- and ICR-heating as well as ECR current drive were more effective in boronized vessels. Boronization resulted in a significant extension of the Ne- and q-region of stable tokamak operation. The density limit rose strongly. In Ohmic H-mode energy confinement time increased significantly (by a factor of 2) after boronization. It rose linearly with plasma current Ip and was 10 times higher than Neo-Alcator time at maximum current. ((orig.))

  9. Site-specific synthesis of a hybrid boron-graphene salt.

    Science.gov (United States)

    Kahlert, Jan U; Austin, Christopher J D; Hall, Andrew J; Rawal, Aditya; Hook, James M; Rendina, Louis M; Choucair, Mohammad

    2016-01-21

    We report the first example of an ionic graphene salt containing boron. An anionic charge is introduced to the graphene surface by means of 7,8-nido-[C2B9H11](-) carborane clusters covalently and electronically bound to the graphene lattice, and this new material was isolated as its Cs(+) salt. PMID:26627051

  10. Investigation of tensile response and thermal conductivity of boron-nitride nanosheets using molecular dynamics simulations

    Science.gov (United States)

    Mortazavi, Bohayra; Rémond, Yves

    2012-06-01

    In this paper, we employed classical molecular dynamics simulations using the Tersoff potential for the evaluation of thermal conductivity and tensile response of single-layer boron-nitride sheets (SBNS). By carrying out uniaxial tension simulations, the elastic moduli of SBNS structures are predicted to be close to those of boron-nitride nanotubes in a range between 0.8 and 0.85 TPa for different chirality directions. Performing non-equilibrium molecular dynamics simulations, the thermal conductivity of SBNS is predicted to be around 80 W/m-K, which is shown to be independent of chirality directions.

  11. Note: Novel diamond anvil cell for electrical measurements using boron-doped metallic diamond electrodes.

    Science.gov (United States)

    Matsumoto, R; Sasama, Y; Fujioka, M; Irifune, T; Tanaka, M; Yamaguchi, T; Takeya, H; Takano, Y

    2016-07-01

    A novel diamond anvil cell suitable for electrical transport measurements under high pressure has been developed. A boron-doped metallic diamond film was deposited as an electrode on a nano-polycrystalline diamond anvil using a microwave plasma-assisted chemical vapor deposition technique combined with electron beam lithography. The maximum pressure that can be achieved by this assembly is above 30 GPa. We report electrical transport measurements of Pb up to 8 GPa. The boron-doped metallic diamond electrodes showed no signs of degradation after repeated compression. PMID:27475610

  12. Application of neutron induced radiography technique in determination of boron in aluminium

    International Nuclear Information System (INIS)

    The technique of Neutron Induced Radiography has been applied to determine boron concentration and its spatial distribution in aluminium using Allyl diglycol carbonate (CR-39) detectors. The technique is based upon the simultaneous irradiation of sample and a standard fixed on a track detector with thermal neutrons and the counting of alpha and /sup 7/Li tracks produced in the detector from the nuclear reaction /sup 10/B(n,α)/sup 7/Li after chemical etching. Boron concentration is determined by comparing the /sup 7/Li and alpha particle tracks density with that of a standard of known boron concentration. Boron concentration in aluminium has been found to be (135.8 ±0.7) ppm in this study which is on the higher side within the normal range reported in the literature. The technique of boron determination by Neutron Induced Radiography is a simple and reliable. It can be used to study the other α-emitting radionuclides in minerals and other materials. (author)

  13. Atomic layer deposition of boron-containing films using B2F4

    International Nuclear Information System (INIS)

    Ultrathin and conformal boron-containing atomic layer deposition (ALD) films could be used as a shallow dopant source for advanced transistor structures in microelectronics manufacturing. With this application in mind, diboron tetrafluoride (B2F4) was explored as an ALD precursor for the deposition of boron containing films. Density functional theory simulations for nucleation on silicon (100) surfaces indicated better reactivity of B2F4 in comparison to BF3. Quartz crystal microbalance experiments exhibited growth using either B2F4-H2O for B2O3 ALD, or B2F4-disilane (Si2H6) for B ALD, but in both cases, the initial growth per cycle was quite low (≤0.2 Å/cycle) and decreased to near zero growth after 8–30 ALD cycles. However, alternating between B2F4-H2O and trimethyl aluminum (TMA)-H2O ALD cycles resulted in sustained growth at ∼0.65 Å/cycle, suggesting that the dense –OH surface termination produced by the TMA-H2O combination enhances the uptake of B2F4 precursor. The resultant boron containing films were analyzed for composition by x-ray photoelectron spectroscopy, and capacitance measurements indicated an insulating characteristic. Finally, diffused boron profiles less than 100 Å were obtained after rapid thermal anneal of the boron containing ALD film

  14. Synthesis and properties of low-carbon boron carbides

    International Nuclear Information System (INIS)

    This paper reports on the production of boron carbides of low carbon content (3 and CCl4 at 1273-1673 K in a chemical vapor deposition (CVD) reactor. Transmission electron microscopy (TEM) revealed that phase separation had occurred, and tetragonal boron carbide was formed along with β-boron or α-boron carbide under carbon-depleted gas-phase conditions. At temperatures greater than 1390 degrees C, graphite substrates served as a carbon source, affecting the phases present. A microstructure typical of CVD-produced α-boron carbide was observed. Plan view TEM of tetragonal boron carbide revealed a blocklike structure

  15. Development of magnetic resonance technology for noninvasive boron quantification

    International Nuclear Information System (INIS)

    Boron magnetic resonance imaging (MRI) and spectroscopy (MRS) were developed in support of the noninvasive boron quantification task of the Idaho National Engineering Laboratory (INEL) Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) program. The hardware and software described in this report are modifications specific to a GE Signa trademark MRI system, release 3.X and are necessary for boron magnetic resonance operation. The technology developed in this task has been applied to obtaining animal pharmacokinetic data of boron compounds (drug time response) and the in-vivo localization of boron in animal tissue noninvasively. 9 refs., 21 figs

  16. Improving tribological properties of sputtered boron carbide coatings by process modifications

    Energy Technology Data Exchange (ETDEWEB)

    Eckardt, T.; Bewilogua, K. [Fraunhofer-Institut fuer Schicht- und Oberflaechentechnik, Braunschweig (Germany); van der Kolk, G.; Hurkmans, T.; Trinh, T.; Fleischer, W. [Hauzer Techno Coating Europe BV, Van Heemskerckweg 22, NL-5920, Venlo (Netherlands)

    2000-04-03

    Boron carbide coatings are well-known for extreme hardness and excellent wear resistance. In this paper a d.c. magnetron sputter process for the deposition of boron carbide coatings is described. It is shown that by adding small amounts of a hydrocarbon reactive gas (in this case acetylene) the coefficient of friction can be reduced from 0.8 down to 0.2. Results from a laboratory scale deposition device are successfully transferred to an industrial batch coater. The coating adhesion is well enhanced by a titanium interlayer. From the analysis of the chemical composition and from hardness values it is concluded that a structural modification is responsible for the improvement of sliding behaviour. It is suggested that the introduction of additional bondings reduces the brittleness of boron carbide. Furthermore, a comparison with metal-containing amorphous carbon coatings (Me-DLC) reveals several similarities. (orig.)

  17. A novel method of boron delivery using sodium iodide symporter for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) effectiveness depends on the preferential sequestration of boron in cancer cells relative to normal tissue cells. We present a novel strategy for sequestering boron using an adenovirus expressing the sodium iodide symporter (NIS). Human glioma grown subcutaneously in athymic mice and orthotopic rat brain tumors were transfected with NIS using a direct tumor injection of adenovirus. Boron bound as sodium tetrafluoroborate (NaBF4) was administered systemically several days after transfection. Tumors were excised hours later and assessed for boron concentration using inductively coupled plasma atomic emission spectroscopy. In the human glioma transfected with NIS, boron concentration was more than 10 fold higher with 100 mg/kg of NaBF4, compared to tumor not transfected. In the orthotopic tumor model, the presence of NIS conferred almost 4 times the boron concentration in rat tumors transfected with human virus compared with contralateral normal brain not transfected. We conclude that adenovirus expressing NIS has the potential to be used as a novel boron delivery agent and should be explored for future clinical applications. (author)

  18. Spectromicroscopy of boron for the optimization of boron neutron capture therapy (BNCT) for cancer

    International Nuclear Information System (INIS)

    We used synchrotron spectromicroscopy to study the microscopic distribution of boron in rat brain tumour and healthy tissue in the field of boron neutron capture therapy (BNCT). The success of this experimental cancer therapy depends on the preferential uptake of 10B in tumour cells after injection of a boron compound (in our case B12H11SH, or BSH). With the Mephisto (microscope a emission de photoelectrons par illumination synchrotronique de type onduleur) spectromicroscope, high-magnification imaging and chemical analysis was performed on brain tissue sections from a rat carrying an implanted brain tumour and the results were compared with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) detection of boron in bulk tissue. Boron was found to have been taken up more favourably by regions of tumour rather than healthy tissue, but the resulting boron distribution in the tumour was inhomogeneous. The results demonstrate that Mephisto can perform microchemical analysis of tissue sections, detect and localize the presence of boron with submicron spatial resolution. The application of this technique to boron in brain tissue can therefore be used to evaluate the current efforts to optimize BNC therapy. (author)

  19. Isotope targets prepared by vapor deposition

    International Nuclear Information System (INIS)

    As the state of the art for producing thin films has developed, the parameters set by the experiments have in turn become more stringent. Often these targets must be of high purity, extremely thin, self-supporting, and of accurately determined thickness. In addition, the target material may be an expensive isotope which must be reduced to elemental form at the time of vapor deposition. Methods of producing some of these targets will be discussed with such examples as calcium, magnesium and boron

  20. Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

    Science.gov (United States)

    Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

    1993-01-01

    Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

  1. Boron-11 NMR spectroscopy of excised mouse tissues after infusion of boron compound used in neutron capture therapy

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is based on selective boron uptake by the tumor and in situ activation by neutron beam. The authors propose the use of B-11 MR spectroscopy to noninvasively study boron uptake in animal tumor models. Sodium mercaptoundeca-hydrododecaborate was infused into female BALB/cJ mice and liver, brain, spleen, kidney, and tumor tissues were excised for MR (27.4MHz) and total boron content measurements. Boron-11 was easily detectable in tumor, liver, spleen, and skin. The results gave a very good correlation (correlation coefficient of .997) between B-11 MR measurements and total boron content of excised mouse tissues

  2. Application of drug delivery system for boron neutron capture therapy. Basic research toward clinical application

    International Nuclear Information System (INIS)

    Tumour cell destruction in boron neutron-capture therapy (BNCT) is due to the nuclear reaction between 10B and thermal neutrons (10B+1n → 7Li+4He (α) +2.31 MeV (93.7%)/2.79 MeV (6.3%)). The resulting lithium ions and αparticles are high linear energy transfer (LET) particles which give high biological effect. Their short range in tissue (5-9 μm) restricts radiation damage to those cells in which boron atoms are located at the time of neutron irradiation. BNCT has been applied clinically for the treatment of malignant brain tumors, malignant melanoma, head and neck cancer and hepatoma etc, recently. Sodium borocaptate (Na210B12H11SH; BSH) and borono-phenylalanine (10BPA) are currently being used in clinical treatments. To achieve the selective delivery of boron atoms to cancer cells, drug delivery system (DDS) becomes an attractive intelligent technology as targeting and controlled release of drugs. We have firstly reported that 10B atoms delivered by immunoliposomes are cytotoxic to human pancreatic carcinoma cells (AsPC-1) after thermal neutron irradiation in vitro. The intra-tumoural injection of boronated immunoliposomes can increase the retention of 10B atoms in tumour cells, causing suppression of tumour growth in vivo following thermal neutron irradiation. We prepared polyethylene-glycol binding liposomes (PEG-liposomes) as an effective 10B carrier to obviate phagocytosis by reticuloendotherial systems. We had prepared 10BSH entrapped Water-in-Oil-in-Water (WOW) emulsion. The 10B concentration in VX-2 tumour after intra-arterial injection of 10BSH entrapped WOW emulsion was superior to the groups of 10BSH entrapped conventional Lipiodol mix emulsion. 10Boron entrapped WOW emulsion is one of the most useful for intra-arterial boron delivery carrier on BNCT to hepatocellular carcinoma. (author)

  3. Oilseed rape genotypes response to boron toxicity

    Directory of Open Access Journals (Sweden)

    Savić Jasna

    2013-01-01

    Full Text Available Response of 16 oilseed rape genotypes to B (boron toxicity was analyzed by comparing the results of two experiments conducted in a glasshouse. In Experiment 1 plants were grown in standard nutrient solutions with 10 µMB (control and 1000 µM B. Relative root and shoot growth varied from 20-120% and 31-117%, respectively. Variation in B concentration in shoots was also wide (206.5-441.7 µg B g-1 DW as well as total B uptake by plant (62.3-281.2 µg B g1. Four selected genotypes were grown in Experiment 2 in pots filled with high B soil (8 kg ha-1 B; B8. Shoot growth was not affected by B8 treatment, while root and shoot B concentration was significantly increased compared to control. Genotypes Panther and Pronto which performed low relative root and shoot growth and high B accumulation in plants in Experiment 1, had good growth in B8 treatment. In Experiment 2 genotype NS-L-7 had significantly lower B concentration in shots under treatment B8, but also very high B accumulation in Experiment 1. In addition, cluster analyses classified genotypes in three groups according to traits contrasting in their significance for analyzing response to B toxicity. The first group included four varieties based on their shared characteristics that have small value for the relative growth of roots and shoots and large values of B concentration in shoot. In the second largest group were connected ten genotypes that are heterogeneous in traits and do not stand out on any characteristic. Genotypes NS-L-7 and Navajo were separated in the third group because they had big relative growth of root and shoot, but also a high concentration of B in the shoot, and high total B uptake. Results showed that none of tested genotypes could not be recommended for breeding process to tolerance for B toxicity. [Projekat Ministarstva nauke Republike Srbije, br. OI 173028

  4. Boron neutron capture synovectomy (BNCS) as a potential therapy for rheumatoid arthritis: boron biodistribution study in a model of antigen-induced arthritis in rabbits.

    Science.gov (United States)

    Trivillin, Verónica A; Abramson, David B; Bumaguin, Gaston E; Bruno, Leandro J; Garabalino, Marcela A; Monti Hughes, Andrea; Heber, Elisa M; Feldman, Sara; Schwint, Amanda E

    2014-11-01

    Boron neutron capture synovectomy (BNCS) is explored for the treatment of rheumatoid arthritis (RA). The aim of the present study was to perform boron biodistribution studies in a model of antigen-induced arthritis (AIA) in female New Zealand rabbits, with the boron carriers boronophenylalanine (BPA) and sodium decahydrodecaborate (GB-10) to assess the potential feasibility of BNCS for RA. Rabbits in chronic phase of AIA were used for biodistribution studies employing the following protocols: intra-articular (ia) (a) BPA-f 0.14 M (0.7 mg (10)B), (b) GB-10 (5 mg (10)B), (c) GB-10 (50 mg (10)B) and intravenous (iv), (d) BPA-f 0.14 M (15.5 mg (10)B/kg), (e) GB-10 (50 mg (10)B/kg), and (f) BPA-f (15.5 mg (10)B/kg) + GB-10 (50 mg (10)B/kg). At different post-administration times (13-85 min for ia and 3 h for iv), samples of blood, pathological synovium (target tissue), cartilage, tendon, muscle, and skin were taken for boron measurement by inductively coupled plasma mass spectrometry. The intra-articular administration protocols at 20 ppm) in the pathological synovium. Dosimetric estimations suggest that BNCS would be able to achieve a therapeutically useful dose in pathological synovium without exceeding the radiotolerance of normal tissues in the treatment volume, employing boron carriers approved for use in humans. Radiobiological in vivo studies will be necessary to determine the actual therapeutic efficacy of BNCS to treat RA in an experimental model. PMID:25156017

  5. Boron: out of the sky and onto the ground

    International Nuclear Information System (INIS)

    Now an accepted, engineered material for aerospace applications, boron is taking its place on the ground. Both current production applications, prototype (development) applications, and speculative applications abound. In the leisure product market, boron epoxy or boron aluminum has been used or tried in golf clubs (in combination with graphite epoxy or to reinforce aluminum or steel), in tennis racquets, in bicycles, racing shells, skis and skipoles, bows and arrows, and others. In the industrial area, boron has been used to reduce fatigue, increase stiffness, or for its abrasive properties. Textile machinery, honing tools, and cut off wheels or saws are among the applications. In the medical field, prosthetics and orthotic braces, wheel chairs, canes, and crutches are all good applications for boron. Applications for boron in transportation, construction, and heavy industry are also possible. The volume of boron used in these applications could have a major impact on prices, making boron composite parts cost competitive with conventional materials. (U.S.)

  6. 15th International Conference on Boron Chemistry (IMEBORON XV)

    Czech Academy of Sciences Publication Activity Database

    Grüner, Bohumír; Štíbr, Bohumil

    2015-01-01

    Roč. 87, č. 2 (2015), s. 121. ISSN 0033-4545 Institutional support: RVO:61388980 Keywords : boranes * boron * boron materials * carboranes * IMEBORON XV * medicinal chemistry Subject RIV: CA - Inorganic Chemistry

  7. Influence of deposition parameters on surface roughness and mechanical properties of boron carbon nitride coatings synthesized by ion beam assisted deposition

    International Nuclear Information System (INIS)

    Boron carbon nitride (BCN) coatings were deposited on Si(100) wafers and Si3N4 disks by using ion beam assisted deposition from a boron carbide target. The BCN coatings were synthesized by the reaction between boron and carbon vapor as well as nitrogen ion simultaneously. The influence of deposition parameters such as ion acceleration voltage, ion acceleration current density and deposition ratio on the surface roughness and mechanical properties of the BCN coatings was investigated. The surface roughness was determined by using atomic force microscopy and the mechanical properties of the BCN coatings were evaluated by nano-indentation tests and friction tests in N2 gas. The composition and chemical bonding of the BCN coatings were analyzed by using X-ray photoelectron spectroscopy. The results showed that the lower deposition rate, the smaller surface roughness and higher nano-hardness the BCN coatings were. The BCN coating with the smoothest surface (R a = 0.25 nm and R P-V = 2.8 nm) and the highest nanohardness of 33 GPa as well as excellent friction property were obtained at 0.5 nm/s and the nitrogen ions were generated at 2.0 kV and 60 μA/cm2, and the chemical composition of this BCN coating was 49 at.% B, 42 at.% C and 9 at.% N. Moreover, there were several bonding states such as B-N, B-C and C-N with B-C-N hybridization in this BCN coating

  8. First gaseous boronization during pulsed discharge cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J., E-mail: jinseok@nfri.re.kr [Department of Physics, University of Wisconsin, Madison, WI (United States); Den Hartog, D.J.; Goetz, J.A.; Weix, P.J.; Limbach, S.T. [Department of Physics, University of Wisconsin, Madison, WI (United States)

    2013-01-15

    The first successful gaseous boronization during a pulsed discharge is reported. Sublimation of o-carborane (C{sub 2}B{sub 10}H{sub 12}) combined with pulsed discharge plasmas with a repetition rate of 1 Hz is used to produce a hard boron-containing coating for reversed field pinch (RFP) plasmas in the Madison Symmetric Torus. X-ray photoelectron spectroscopy with Ar ion beam etching for silicon coupons installed at the plasma boundary shows about 60% boron concentration in the deposited layer. Both profilometer and scanning electron microscope analyses of the silicon coupons imply a strong toroidally non-uniform deposition depending on the location of the o-carborane injection. The layer thickness ranges from 50 to 300 nm. Ellipsometry calibrated with the profilometer results yields a refractive index of 2.2-2.3 for the films. The high refractive index implies that the coating is hard and has a well-ordered morphology. A reduction in wall recycling has consistently been observed after all boronization sessions. Comparison of the X-ray spectra in standard RFP plasmas before and after boronization indicates a slight decrease in the effective ionic charge.

  9. Boron isotope fractionation during brucite deposition from artificial seawater

    OpenAIRE

    J. Xiao; Xiao, Y. K.; Liu, C. Q.; Z. D. Jin

    2011-01-01

    Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite. The results show that both concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (Kd) between deposited brucite and final seawater are controll...

  10. Characterization of boron carbide with an electron microprobe

    Science.gov (United States)

    Matteudi, G.; Ruste, J.

    1983-01-01

    Within the framework of a study of heterogeneous materials (Matteudi et al., 1971: Matteudi and Verchery, 1972) thin deposits of boron carbide were characterized. Experiments using an electronic probe microanalyzer to analyze solid boron carbide or boron carbide in the form of thick deposits are described. Quantitative results on boron and carbon are very close to those obtained when applying the Monte Carlo-type correction calculations.

  11. Glass manufacturing process having boron and fluorine pollution abating features

    Energy Technology Data Exchange (ETDEWEB)

    Froberg, M.L.; Schroeder, C.F.

    1981-11-03

    Boron and/or fluorine values are reclaimed from a boron and/or fluorine laden gas stream emanating from a glass melter by means of a preheating bed of glass-forming batch agglomerates. The boron and/or fluorine values in such gases are first reacted with a boron and/or fluorine reactive material and the gases then conveyed into such a preheating bed to separate at least a portion of the reaction products.

  12. Glass manufacturing process having boron and fluorine pollution abating features

    International Nuclear Information System (INIS)

    Boron and/or fluorine values are reclaimed from a boron and/or fluorine laden gas stream emanating from a glass melter by means of a preheating bed of glass-forming batch agglomerates. The boron and/or fluorine values in such gases are first reacted with a boron and/or fluorine reactive material and the gases then conveyed into such a preheating bed to separate at least a portion of the reaction products

  13. Chemical Sharpening, Shortening, and Unzipping of Boron Nitride Nanotubes

    Science.gov (United States)

    Liao, Yunlong; Chen, Zhongfang; Connell, John W.; Fay, Catharine C.; Park, Cheol; Kim, Jae-Woo; Lin, Yi

    2014-01-01

    Boron nitride nanotubes (BNNTs), the one-dimensional member of the boron nitride nanostructure family, are generally accepted to be highly inert to oxidative treatments and can only be covalently modifi ed by highly reactive species. Conversely, it is discovered that the BNNTs can be chemically dispersed and their morphology modifi ed by a relatively mild method: simply sonicating the nanotubes in aqueous ammonia solution. The dispersed nanotubes are significantly corroded, with end-caps removed, tips sharpened, and walls thinned. The sonication treatment in aqueous ammonia solution also removes amorphous BN impurities and shortened BNNTs, resembling various oxidative treatments of carbon nanotubes. Importantly, the majority of BNNTs are at least partially longitudinally cut, or "unzipped". Entangled and freestanding BN nanoribbons (BNNRs), resulting from the unzipping, are found to be approximately 5-20 nm in width and up to a few hundred nanometers in length. This is the fi rst chemical method to obtain BNNRs from BNNT unzipping. This method is not derived from known carbon nanotube unzipping strategies, but is unique to BNNTs because the use of aqueous ammonia solutions specifi cally targets the B-N bond network. This study may pave the way for convenient processing of BNNTs, previously thought to be highly inert, toward controlling their dispersion, purity, lengths, and electronic properties.

  14. Marek's Disease Viral Interleukin-8 Promotes Lymphoma Formation through Targeted Recruitment of B Cells and CD4+ CD25+ T Cells

    OpenAIRE

    Engel, Annemarie T.; Selvaraj, Ramesh K.; Kamil, Jeremy P.; Osterrieder, Nikolaus; Kaufer, Benedikt B

    2012-01-01

    Marek's disease virus (MDV) is a cell-associated and highly oncogenic alphaherpesvirus that infects chickens. During lytic and latent MDV infection, a CXC chemokine termed viral interleukin-8 (vIL-8) is expressed. Deletion of the entire vIL-8 open reading frame (ORF) was shown to severely impair disease progression and tumor development; however, it was unclear whether this phenotype was due to loss of secreted vIL-8 or of splice variants that fuse exons II and III of vIL-8 to certain upstrea...

  15. Determination of boron in human serum by inductively coupled plasma mass spectrometry after a simple dilution of the sample

    International Nuclear Information System (INIS)

    A method for the determination of boron in human serum is described. Serum samples were only treated with 0.14 M HNO3 (a five-fold dilution). After addition of beryllium as internal standard to correct for matrix effects, samples were introduced with a concentric nebulizer to an inductively coupled plasma mass spectrometer. The magnitude of the boron ion signal was optimized by adjusting the lens voltages and the nebulizer gas flow rate and memory effects, which can be experienced with the conventional methodology for sample introduction, were reduced to an acceptable level by the use of a short (2 min) cleanout procedure. To avoid the overlap from the intense 12C+-peak with the 11B+-peak, the 10B+-peak was used for the boron determinations. This procedure gave a boron blank level of about 1.7 μg l-1 and a detection limit of 0.5 μg l-1 for human serum. External calibration was applied for the quantitation of boron. The proposed method was tested by analysing a 'second-generation' biological reference material Freeze-Dried Human Serum (University of Ghent). Results are also given for three other biological reference materials, namely Wheat Flour SRM 1567a, Bovine Liver SRM 1577a and Total Diet SRM 1548 (National Institute of Standards and Technology). Analyses of serum samples from twelve healthy individuals yielded boron concentrations ranging from 4.1 to 25.8 μg l-1

  16. Synthesis of multiwall boron nitride nanotubes dependent on crystallographic structure of boron

    International Nuclear Information System (INIS)

    Synthesis and growth of multiwall boron nitride nanotubes (BNNTs) under the B and ZrO2 seed system in the milling–annealing process were investigated. BNNTs were synthesized by annealing a mechanically activated boron powder under nitrogen environment. We explored the aspects of the mechanical activation energy transferred to milled crystalline boron powder producing structural disorder and borothermal reaction of the ZrO2 seed particles on the synthesis of BNNTs during annealing. Under these circumstances, the chemical reaction of amorphous boron coated on the seed nanoparticles with nitrogen synthesizing amorphous BN could be enhanced. It was found that amorphous BN was crystallized to the layer structure and then grown to multiwall BNNTs during annealing. Especially, bamboo-type multiwall BNNTs were mostly produced and grown to the tail-side of the nanotube not to the round head-side. Open gaps with ∼0.3 nm of the bamboo side walls of BNNTs were also observed. Based on these understandings, it might be possible to produce bamboo-type multiwall BNNTs by optimization of the structure and shape of boron coat on the seed nanoparticles. -- Highlights: ► Structure of B is a key factor for BNNT synthesis for milling–annealing method. ► Amorphous boron is coated on the seed during milling of crystalline boron. ► Amorphous BN nanoclusters are crystallized during annealing. ► Growing of bamboo BNNTs is not to the round head-side but to the tail-side.

  17. INFLUENCE OF FINE-DISPERSED BORON CARBIDE ON THE STRUCTURE AND CHARACTERISTICS OF IRON-BORON ALLOY

    Directory of Open Access Journals (Sweden)

    N. F. Nevar

    2016-02-01

    Full Text Available The influence of boron carbide as fine-dispersed material input into the melt on structure morphology, founding, technological and exploitation characterisstics of cast iron-boron material is shown.

  18. Effectiveness of boron neutron capture therapy for recurrent head and neck malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Itsuro [Department of Oral and Maxillofacial Surgery, II Osaka University, Graduate School of Dentistry, Osaka (Japan)], E-mail: katoitsu@dent.osaka-u.ac.jp; Fujita, Yusei [Department of Oral and Maxillofacial Surgery, II Osaka University, Graduate School of Dentistry, Osaka (Japan); Maruhashi, Akira [Radiation Oncology Research Laboratory, Research Reactor Institut, Kyoto University, Osaka (Japan); Kumada, Hiroaki [Japan Atomic Energy Agency, Tokai Research and Development Center, Ibaraki (Japan); Ohmae, Masatoshi [Department of Oral and Maxillofacial Surgery, Izimisano Municipal Hospital, Rinku General Hospital, Izumisano, Osaka (Japan); Kirihata, Mitsunori [Graduate School of Environment and Life Science, Osaka prefectural University, Osaka (Japan); Imahori, Yoshio [Department of Neurosurgery, Kyoto Prefectural University, Kyoto (Japan); CEO of Cancer Intelligence Care Systems, Inc., Tokyo (Japan); Suzuki, Minoru [Radiation Oncology Research Laboratory, Research Reactor Institut, Kyoto University, Osaka (Japan); Sakrai, Yoshinori [Graduate School of Medicine, Sapporo Medical University of Medicine, Hokkaido (Japan); Sumi, Tetsuro; Iwai, Soichi; Nakazawa, Mitsuhiro [Department of Oral and Maxillofacial Surgery, II Osaka University, Graduate School of Dentistry, Osaka (Japan); Murata, Isao; Miyamaru, Hiroyuki [Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University (Japan); Ono, Koji [Radiation Oncology Research Laboratory, Research Reactor Institut, Kyoto University, Osaka (Japan)

    2009-07-15

    It is necessary to explore new treatments for recurrent head and neck malignancies (HNM) to avoid severe impairment of oro-facial structures and functions. Boron neutron capture therapy (BNCT) is tumor-cell targeted radiotherapy that has significant superiority over conventional radiotherapies in principle. We have treated with BNCT 42 times for 26 patients (19 squamous cell carcinomas (SCC), 4 salivary gland carcinomas and 3 sarcomas) with a recurrent and far advanced HNM since 2001. Results of (1) {sup 10}B concentration of tumor/normal tissue ratios (T/N ratio) of FBPA-PET studies were SCC: 1.8-5.7, sarcoma: 2.5-4.0, parotid tumor: 2.5-3.7. (2) Therapeutic effects were CR: 12 cases, PR: 10 cases, PD: 3 cases NE (not evaluated): 1 case. Response rate was 85%. (3) Improvement of QOL such as a relief of severe pain, bleeding, and exudates at the local lesion, improvement of PS, disappearance of ulceration, covered with normal skin and preserved oral and maxillofacial functions and tissues. (4) Survival periods after BNCT were 1-72 months (mean: 13.6 months). Six-year survival rate was 24% by Kaplan-Meier analysis. (5) Adverse-events were transient mucositis and alopecia in most of the cases; three osteomyelitis and one brain necrosis were recognized. These results indicate that BNCT represents a new and promising treatment approach for advanced HNM.

  19. Effectiveness of boron neutron capture therapy for recurrent head and neck malignancies

    International Nuclear Information System (INIS)

    It is necessary to explore new treatments for recurrent head and neck malignancies (HNM) to avoid severe impairment of oro-facial structures and functions. Boron neutron capture therapy (BNCT) is tumor-cell targeted radiotherapy that has significant superiority over conventional radiotherapies in principle. We have treated with BNCT 42 times for 26 patients (19 squamous cell carcinomas (SCC), 4 salivary gland carcinomas and 3 sarcomas) with a recurrent and far advanced HNM since 2001. Results of (1) 10B concentration of tumor/normal tissue ratios (T/N ratio) of FBPA-PET studies were SCC: 1.8-5.7, sarcoma: 2.5-4.0, parotid tumor: 2.5-3.7. (2) Therapeutic effects were CR: 12 cases, PR: 10 cases, PD: 3 cases NE (not evaluated): 1 case. Response rate was 85%. (3) Improvement of QOL such as a relief of severe pain, bleeding, and exudates at the local lesion, improvement of PS, disappearance of ulceration, covered with normal skin and preserved oral and maxillofacial functions and tissues. (4) Survival periods after BNCT were 1-72 months (mean: 13.6 months). Six-year survival rate was 24% by Kaplan-Meier analysis. (5) Adverse-events were transient mucositis and alopecia in most of the cases; three osteomyelitis and one brain necrosis were recognized. These results indicate that BNCT represents a new and promising treatment approach for advanced HNM.

  20. Indication and possibility of boron neutron capture therapy in head and neck cancer

    International Nuclear Information System (INIS)

    Background: Boron neutron capture therapy (BNCT) is a targeted type of radiotherapy that has a number of significant advantages over conventional external beam photon irradiation, especially in that radiation can be selectively delivered to tumor cells. We had, first in the world, treated with BNCT for a patient with recurrent head and neck cancer (HNC) in 2001. Methods : From December, 2001 to February, 2013, we had treated 37 patients with recurrent HNC by means of 54 applications of BNCT at Kyoto University Research Reactor Institute (KURRI) and Japan Atomic Energy Agency (JAEA). All of them had received standard therapy and subsequently developed recurrent disease for which there were no other treatment options. Results : All of the (1) Regression rates were complete response (CR) : 19 patients (51%), partial response (PR) : 14(38%), progressive disease (PD) : 3(8%), and not evaluated (NE) : 1(3%) patient. (2) The overall patient response rate was 91%, though all the patients had advanced disease. The 4-year and 7-year OS rates were 42% and 36%, respectively. (3) BNCT improved quality of life (QOL), performance status (PS) and survival times. (4) The primary adverse events were brain necrosis, osteomyelitis and transient mucositis and alopecia. Conclusions : Our results indicate that we could make sure that safety and effectiveness of BNCT, and BNCT represents a new and promising treatment modality in patients for whom there are no other treatment options. (author)

  1. Colorimetric Sugar Sensing Using Boronic Acid-Substituted Azobenzenes

    Directory of Open Access Journals (Sweden)

    Yuya Egawa

    2014-02-01

    Full Text Available In association with increasing diabetes prevalence, it is desirable to develop new glucose sensing systems with low cost, ease of use, high stability and good portability. Boronic acid is one of the potential candidates for a future alternative to enzyme-based glucose sensors. Boronic acid derivatives have been widely used for the sugar recognition motif, because boronic acids bind adjacent diols to form cyclic boronate esters. In order to develop colorimetric sugar sensors, boronic acid-conjugated azobenzenes have been synthesized. There are several types of boronic acid azobenzenes, and their characteristics tend to rely on the substitute position of the boronic acid moiety. For example, o-substitution of boronic acid to the azo group gives the advantage of a significant color change upon sugar addition. Nitrogen-15 Nuclear Magnetic Resonance (NMR studies clearly show a signaling mechanism based on the formation and cleavage of the B–N dative bond between boronic acid and azo moieties in the dye. Some boronic acid-substituted azobenzenes were attached to a polymer or utilized for supramolecular chemistry to produce glucose-selective binding, in which two boronic acid moieties cooperatively bind one glucose molecule. In addition, boronic acid-substituted azobenzenes have been applied not only for glucose monitoring, but also for the sensing of glycated hemoglobin and dopamine.

  2. Boron-containing amino carboxylic acid compounds and uses thereof

    International Nuclear Information System (INIS)

    Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed

  3. An algorithm for computing thick target differential p-Li neutron yields near threshold

    International Nuclear Information System (INIS)

    The 7Li(p,n)7Be reaction is a good source of neutrons for accelerator boron neutron capture therapy (BNCT). Both reactor and accelerator neutron sources produce fast neutrons, which must be moderated since BNCT uses epithermal neutrons. Near-threshold BNCT uses proton energies only tens of keV above the reaction threshold, which reduces the thick target neutron yield but also produces neutrons closer to epithermal energies, so that less moderation is required. Accurate methods for calculating near-threshold differential neutron yields from thick targets of lithium, as well as certain low weight lithium compounds, were developed for BNCT source design. Neutron yields for proton beams up to 2.8 MeV will be presented. Good agreement with yields from several targets will be demonstrated. copyright 1999 American Institute of Physics

  4. Synthesis and anti-oxidation performance of nanoflake-decorated boron nitride hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Li, Juan [College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); Lin, Hong [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Chen, Yongjun, E-mail: chenyj99@163.com [College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China); College of Material and Chemical Engineering, Hainan University, Haikou 570228 (China); Su, Qiaoqiao; Bi, Xiaofan [College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004 (China)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer A novel boron nitride (BN) composite structure composed of nanoflake and hollow microspheres was synthesized. Black-Right-Pointing-Pointer The raw materials are simple precursors of boron and Fe(NO{sub 3}){sub 3}{center_dot}9H{sub 2}O ethanol solution. Black-Right-Pointing-Pointer The structures have a high anti-oxidation temperature of 900 Degree-Sign C. Black-Right-Pointing-Pointer The growth mechanism consists of a combined vapor-liquid-solid (VLS) and vapor-solid (VS) model. - Abstract: In this study, a novel boron nitride composite structure composed of nanoflake-decorated hollow microspheres is demonstrated. A paste-like mixture is firstly prepared by mixing amorphous boron with ferric nitrate ethanol solution, followed by heating at 1300 Degree-Sign C in a flowing ammonia atmosphere for 5 h. Both the nanoflakes and microspheres are composed of crystalline hexagonal boron nitride. The hollow spheres have outer diameters of 0.8-3 {mu}m with thickness of about 300 nm, while the nanoflakes have thicknesses of 2-7 nm and lengths of 10-100 nm. Heating temperature is found to be crucial for the formation of this composite structure. The growth process consists of a vapor-liquid-solid growth stage of smooth hollow microspheres at lower temperature and a vapor-solid growth stage of nanoflakes on the surface of the microspheres at higher temperature. The boron nitride composite structure exhibits excellent anti-oxidation performance up to 900 Degree-Sign C.

  5. 'Sequential' Boron Neutron Capture Therapy (BNCT): A Novel Approach to BNCT for the Treatment of Oral Cancer in the Hamster Cheek Pouch Model

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10B carriers in tumors followed by irradiation with a thermal or epithermal neutron beam. The minor abundance stable isotope of boron, 10B, interacts with low energy (thermal) neutrons to produce high linear energy transfer (LET) a-particles and 7Li ions. These disintegration products are known to have a high relative biological effectiveness (RBE). Their short range (<10 (micro)m) would limit the damage to cells containing 10B (1,2). Thus, BNCT would target tumor tissue selectively, sparing normal tissue. Clinical trials of BNCT for the treatment of glioblastoma multiforme and/or melanoma and, more recently, head and neck tumors and liver metastases, using boronophenylalanine (BPA) or sodium mercaptoundecahydrododecaborane (BSH) as the 10B carriers, have been performed or are underway in Argentina, Japan, the US and Europe (e.g. 3-8). To date, the clinical results have shown a potential, albeit inconclusive, therapeutic advantage for this technique. Contributory translational studies have been carried out employing a variety of experimental models based on the implantation of tumor cells in normal tissue (e.g. 5).

  6. "Sequential” Boron Neutron Capture Therapy (BNCT): A Novel Approach to BNCT for the Treatment of Oral Cancer in the Hamster Cheek Pouch Model

    Energy Technology Data Exchange (ETDEWEB)

    Ana J. Molinari; Andrea Monti Hughes; Elisa M. Heber; Marcela A. Garabalino; Veronica A. Trivillin; Amanda E. Schwint; Emiliano C. C. Pozzi; Maria E. Itoiz; Silvia I. Thorp; Romina F. Aromando; David W. Nigg; Jorge Quintana; Gustavo A. Santa Cruz

    2011-04-01

    Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10B carriers in tumors followed by irradiation with a thermal or epithermal neutron beam. The minor abundance stable isotope of boron, 10B, interacts with low energy (thermal) neutrons to produce high linear energy transfer (LET) a-particles and 7Li ions. These disintegration products are known to have a high relative biological effectiveness (RBE). Their short range (<10 {micro}m) would limit the damage to cells containing 10B (1,2). Thus, BNCT would target tumor tissue selectively, sparing normal tissue. Clinical trials of BNCT for the treatment of glioblastoma multiforme and/or melanoma and, more recently, head and neck tumors and liver metastases, using boronophenylalanine (BPA) or sodium mercaptoundecahydrododecaborane (BSH) as the 10B carriers, have been performed or are underway in Argentina, Japan, the US and Europe (e.g. 3-8). To date, the clinical results have shown a potential, albeit inconclusive, therapeutic advantage for this technique. Contributory translational studies have been carried out employing a variety of experimental models based on the implantation of tumor cells in normal tissue (e.g. 5).

  7. Enhanced Plasma Performance by ICRF Boronization

    Institute of Scientific and Technical Information of China (English)

    万宝年; 赵燕平; 李建刚; 宋梅; 吴振伟; 罗家融; 李成富; 王小明

    2002-01-01

    Boronization with carborane (C2B10H12) by ICRF has been applied routinely to the walls of HT-7 super-conducting tokamak for the reduction of impurity influx, especially carbon and oxygen. Significant suppression of metallic impurities and radiating power fraction are achieved. The improved confinement for both particle and energy is observed in full range of operation parameters. Energy balance analysis shows that electron heat diffusion coefficient is strongly reduced. Measurements by Langmuir probes at the edge plasma show that the poloidal velocity shear after boronization is changed to a profile favoring to good confinement. The main emphasis of this paper is to describe effects of boronization on aspects of the enhanced plasma performance.

  8. Anomalous electronic transport in boron carbides

    Science.gov (United States)

    Emin, D.; Samara, G. A.; Wood, C.

    The boron carbides are composed of icosahedral units, B12 and B11C1, linked together by strong intericosahedral bonds. With such distributions of icosahedral and intericosahedral compositions, boron carbides, B/sub 1-x/C/sub x/, are single phase over 0.1 less than or equal to x less than or equal to 0.2. The electronic transport properties of the boron carbides were examined within this single-phase region. Results are inconsistent with conventional analyses of both itinerant and hopping transport. Most striking are Seebeck coefficients which are both large and rapidly increasing functions of temperature despite thermally activated dc conductivities. These results manifest the hopping of small bipolaronic holes between carbon-containing icosahedral that are inequivalent in energy and electron-lattice coupling strength. Under hydrostatic pressures up to approx. 25 kbar, the dc conductivities increase with pressure. This anomalous behavior for hopping conduction reflects the distinctive structure and bonding of these materials.

  9. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT)

  10. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    Science.gov (United States)

    Singh, Bikramjeet; Singh, Paviter; Kumar, Manjeet; Thakur, Anup; Kumar, Akshay

    2015-05-01

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT).

  11. boron and boron nitride coated nuclear fuel production in plasma atmosphere

    International Nuclear Information System (INIS)

    In these study uranium dioxide (UO2) and 5, 10 % gadolinium oxide (Gd2O3) containing UO2 nuclear fuel pellets were coated with first boron nitride (BN) then boron (B) layers as the results of the reactions between boron trichloride (BCl3) with ammonia (NH3) and BCl3 with hydrogen (H2) in the medium of argon (Ar) plasma created at 650 W and 500 W and 27.12 MHz to increase the fuel burnup efficiency and reactor core life by the method of plasma enhanced chemical vapor deposition (PECVD). Grainy BN and B structures were observed on the photographs taken from scanning electron microscope (SEM)

  12. A system to deposit boron films (boronization) in the DIII-D tokamak

    International Nuclear Information System (INIS)

    A system has been added to the D3-D tokamak to coat its plasma facing surfaces with a film of boron using diborane gas. The system includes special health and safety equipment for handling the diborane gas which is toxic and inflammable. The purpose of the boron film is to reduce the levels of impurity atoms in the D3-D plasmas. Experiments following the application of the boron film in D3-D have led to significant reductions in plasma impurity levels and the observation of a new, very high confinement regime. 9 refs., 1 fig

  13. Intra-Shell boron isotope ratios in benthic foraminifera: Implications for paleo-pH reconstructions

    Science.gov (United States)

    Rollion-Bard, C.; Erez, J.

    2009-12-01

    The boron isotope composition of marine carbonates is considered to be a seawater pH proxy. Nevertheless, the use of δ11B has some limitations: 1) the knowledge of fractionation factor (α4-3) between the two boron dissolved species (boric acid and borate ion), 2) the δ11B of seawater may have varied with time and 3) the amplitude of the "vital effects" of this proxy. Using secondary ion mass spectrometry (SIMS), we looked at the internal variability in the boron isotope ratio of the shallow water, symbionts bearing foraminiferan Amphistegina lobifera. Specimens were cultured at constant temperature (24±0.1 °C) in seawater with pH ranging between 7.90 and 8.45. We performed 6 to 8 measurements of δ11B in each foraminifera. Intra-shell boron isotopes show large variability with an upper threshold value of pH ~ 9. The ranges of the skeletal calculated pH values in different cultured foraminifera, show strong correlation with the culture pH values and may thus serve as proxy for pH in the past ocean.

  14. Boron Nitride Nanotubes for Spintronics

    Directory of Open Access Journals (Sweden)

    Kamal B. Dhungana

    2014-09-01

    Full Text Available With the end of Moore’s law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT, which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics.

  15. Boron neutron capture therapy for oral precancer: proof of principle in an experimental animal model

    Energy Technology Data Exchange (ETDEWEB)

    A. Monti Hughes; ECC Pozzi; S. Thorp; M. A. Garabalino; R. O. Farias; S. J. Gonzalez; E. M. Heber; M. E. Itoiz; R. F. Aromando; A. J. Molinari; M. Miller; D. W. Nigg; P. Curotto; V. A. Trivillin; A. E. Schwint

    2013-11-01

    Field-cancerized tissue can give rise to second primary tumours, causing therapeutic failure. Boron neutron capture therapy (BNCT) is based on biological targeting and would serve to treat undetectable foci of malignant transformation. The aim of this study was to optimize BNCT for the integral treatment for oral cancer, with particular emphasis on the inhibitory effect on tumour development originating in precancerous conditions, and radiotoxicity of different BNCT protocols in a hamster cheek pouch oral precancer model.

  16. P13.09ADVANCES IN CLINICAL APPLICATION OF BORON NEUTRON CAPTURE THERAPY (BNCT) IN GLIOBLASTOMA

    OpenAIRE

    Detta, A.; Cruickshank, G.C.; Green, S.; Lockyer, N.P.; Ngoga, D.; Ghani, Z.; Phoenix, B

    2014-01-01

    BNCT is a biologically targeted form of enhanced cellular radiotherapy where preferential accumulation of boron in the cancerous as opposed to adjacent normal cells is able to interact with incident neutrons to cause irreversible alpha particle DNA damage. The key to the implementation of this potentially powerful and selective therapy is the delivery of at least 30ppm 10B within the tumour tissue while minimising superfluous 10B in healthy tissue. It is thus an elegant technique for treating...

  17. Boron neutron capture therapy of malignant brain tumors at the Brookhaven Medical Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Joel, D.D.; Coderre, J.A.; Chanana, A.D. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

    1996-12-31

    Boron neutron capture therapy (BNCT) is a bimodal form of radiation therapy for cancer. The first component of this treatment is the preferential localization of the stable isotope {sup 10}B in tumor cells by targeting with boronated compounds. The tumor and surrounding tissue is then irradiated with a neutron beam resulting in thermal neutron/{sup 10}B reactions ({sup 10}B(n,{alpha}){sup 7}Li) resulting in the production of localized high LET radiation from alpha and {sup 7}Li particles. These products of the neutron capture reaction are very damaging to cells, but of short range so that the majority of the ionizing energy released is microscopically confined to the vicinity of the boron-containing compound. In principal it should be possible with BNCT to selectively destroy small nests or even single cancer cells located within normal tissue. It follows that the major improvements in this form of radiation therapy are going to come largely from the development of boron compounds with greater tumor selectivity, although there will certainly be advances made in neutron beam quality as well as the possible development of alternative sources of neutron beams, particularly accelerator-based epithermal neutron beams.

  18. The measurement of thermal neutron flux depression for determining the concentration of boron in blood

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a form of targeted radiotherapy that relies on the uptake of the capture element boron by the volume to be treated. The treatment procedure requires the measurement of boron in the patient's blood. The investigation of a simple and inexpensive method for determining the concentration of the capture element 10B in blood is described here. This method, neutron flux depression measurement, involves the determination of the flux depression of thermal neutrons as they pass through a boron-containing sample. It is shown via Monte Carlo calculations and experimental verification that, for a maximum count rate of 1x104 counts/s measured by the detector, a 10 ppm 10B sample of volume 20 ml can be measured with a statistical precision of 10% in 32±2 min. For a source activity of less than 1.11x1011 Bq and a maximum count rate of less than 1x104 counts/s, a 10 ppm 10B sample of volume 20 ml can be measured with a statistical precision of 10% in 58±3 min. It has also been shown that this technique can be applied to the measurement of the concentration of any element with a high thermal neutron cross section such as 157Gd. (author)

  19. New blocking antibodies impede adhesion, migration and survival of ovarian cancer cells, highlighting MFGE8 as a potential therapeutic target of human ovarian carcinoma.

    Directory of Open Access Journals (Sweden)

    Lorenzo Tibaldi

    Full Text Available Milk Fat Globule--EGF--factor VIII (MFGE8, also called lactadherin, is a secreted protein, which binds extracellularly to phosphatidylserine and to αvβ3 and αvβ5 integrins. On human and mouse cells expressing these integrins, such as endothelial cells, phagocytes and some tumors, MFGE8/lactadherin has been shown to promote survival, epithelial to mesenchymal transition and phagocytosis. A protumoral function of MFGE8 has consequently been documented for a few types of human cancers, including melanoma, a subtype of breast cancers, and bladder carcinoma. Inhibiting the functions of MFGE8 could thus represent a new type of therapy for human cancers. Here, we show by immunohistochemistry on a collection of human ovarian cancers that MFGE8 is overexpressed in 45% of these tumors, and we confirm that it is specifically overexpressed in the triple-negative subtype of human breast cancers. We have established new in vitro assays to measure the effect of MFGE8 on survival, adhesion and migration of human ovarian and triple-negative breast cancer cell lines. Using these assays, we could identify new MFGE8-specific monoclonal antibodies, which efficiently blocked these three tumor-promoting effects of MFGE8. Our results suggest future use of MFGE8-blocking antibodies as new anti-cancer therapeutics in subgroups of ovarian carcinoma, and triple-negative breast carcinoma patients.

  20. Therapeutic efficacy of boron neutron capture therapy mediated by boron-rich liposomes for oral cancer in the hamster cheek pouch model

    International Nuclear Information System (INIS)

    Unilamellar liposomes formulated with an equimolar mixture of cholesterol and 1,2-distearoyl-sn-glycero-3-phosphocholine, incorporating K[nido-7-CH3(CH2)15-7,8-C2B9H11] in the lipid bilayer, and encapsulating Na3[ae-B10-H9)-2-NH3B10H8] were prepared by probe sonication and investigated in vivo. Microwave assisted digestion followed by inductively coupled plasma-optical emission spectroscopy was utilized to determine the biodistribution of boron in various tissues following either a single tail vein injection or two identical injections (separated by 24 hours) of the liposomal suspension in BALB/c mice bearing EMT6 mammary adenocarcinomas in their right flank. Double-injection protocols resulted in a boron content in the tumor exceeding 50 µg of boron per gram of tissue for 48 to 72 hours subsequent to the initial injection while tumor:blood boron ratios were more ideal from 54 hours (1.9:1) to 96 hours (5.7:1) subsequent to the initial injection. Tumor bearing mice were given a double-injection of liposomes containing the 10B-enriched analogs of the aforementioned agents and subjected to a 30 minute irradiation by thermal neutrons with a flux of 8.8 x 108 (±7%) neutrons/cm2 s integrated over the energy range of 0.0 - 0.414 eV. Significant tumor response for a single BNCT treatment was demonstrated by growth curves versus a control group. Vastly diminished tumor growth was witnessed at 14 days (186% increase versus 1551% in controls) in mice that were given a second injection/radiation treatment 7 days after the first. Mice given a one hour neutron irradiation following the double-injection of liposomes had a similar response (169% increase at 14 days) suggesting that neutron fluence is the limiting factor towards BNCT efficacy in this study.

  1. Can Two-Dimensional Boron Superconduct?

    Science.gov (United States)

    Penev, Evgeni S; Kutana, Alex; Yakobson, Boris I

    2016-04-13

    Two-dimensional boron is expected to exhibit various structural polymorphs, all being metallic. Additionally, its small atomic mass suggests strong electron-phonon coupling, which in turn can enable superconducting behavior. Here we perform first-principles analysis of electronic structure, phonon spectra, and electron-phonon coupling of selected 2D boron polymorphs and show that the most stable structures predicted to feasibly form on a metal substrate should also exhibit intrinsic phonon-mediated superconductivity, with estimated critical temperature in the range of Tc ≈ 10-20 K. PMID:27003635

  2. Thermal conductivity behavior of boron carbides

    Science.gov (United States)

    Wood, C.; Zoltan, A.; Emin, D.; Gray, P. E.

    1983-01-01

    Knowledge of the thermal conductivity of boron carbides is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. The thermal diffusivity of hot pressed boron carbide B/sub 1-x/C/sub x/ samples as a function of composition, temperature and temperature cycling was measured. These data in concert with density and specific heat data yield the thermal conductivities of these materials. The results in terms of a structural model to explain the electrical transport data and novel mechanisms for thermal conduction are discussed.

  3. Evaluation of Ground-Water and Boron Sources by Use of Boron Stable-Isotope Ratios, Tritium, and Selected Water-Chemistry Constituents near Beverly Shores, Northwestern Indiana, 2004

    Science.gov (United States)

    Buszka, Paul M.; Fitzpatrick, John A.; Watson, Lee R.; Kay, Robert T.

    2007-01-01

    from human-affected boron sources. Boron concentrations in potential ground-water sources of boron were largest (15,700 to 24,400 ?g/L) in samples of CCP-affected surficial aquifer water from four wells at a CCP landfill and smallest (27 to 63 ?g/L) in three wells in the surficial aquifer that were distant from human-affected boron sources. Boron concentrations in water from the basal sand aquifer ranged from 656 ?g/L to 1,800 ?g/L. Boron concentrations in water from three domestic-wastewater-affected surficial aquifer wells ranged from 84 to 387 ?g/L. Among the representative ground-water samples, boron concentrations from all four samples of CCP-affected surficial aquifer water and four of five samples of water from the basal sand aquifer had concentrations greater than the RAL. A comparison of boron concentrations in acid-preserved and unacidified samples indicated that boron concentrations reported for this investigation may be from about 11 to 16 percent less than would be reported in a standard analysis of an acidified sample. The stable isotope boron-11 was most enriched in comparison to boron-10 in ground water from a confined aquifer, the basal sand aquifer (d11B, 24.6 to 34.0 per mil, five samples); it was most depleted in CCP-affected water from the surficial aquifer (d11B, 0.1 to 6.6 per mil, four samples). Domestic-wastewater-affected water from the surficial aquifer (d11B, 8.7 to 11.7 per mil, four samples) was enriched in boron-11, in comparison to individual samples of a borax detergent additive and a detergent with perborate bleach; it was intermediate in composition between basal sand aquifer water and CCP-affected water from the surficial aquifer. The similarity between a ground-water sample from the surficial aquifer and a hypothetical mixture of unaffected surficial aquifer and basal sand aquifer waters indicates the potential for long-term upward discharge of ground water into the surficial aquifer from one or more confined aquifers. Est

  4. Radio-frequency sputter deposition of boron nitride based thin films

    International Nuclear Information System (INIS)

    Thin films (∼2 μm) of boron nitride, titanium boron nitride, and titanium aluminum boron nitride have been grown on molybdenum, niobium, and cemented carbide substrates employing nonreactive as well as reactive rf magnetron sputter deposition from either a BN, a TiN-BN, or a TiN--AlN--BN target. Substrates have been rf biased, with dc potentials up to -200 V. By means of nonreactive sputtering mixed-phase structures with dominant phases B48B2N2 (using a BN target), or B48B2N2 and hexagonal Ti--B--N (using a TiN--BN or a TiN--AlN--BN target) are formed. Reactive deposition leads to the existence of hexagonal BN in all deposition modes. In the cases of Ti--B--N and Ti--Al--B--N films this phase is accompanied by fcc Ti--B--N. SEM cross sections revealed very fine grained to fracture-amorphous film structures. Hardness measurements gave the following maximum HV 0.02 values: B--N films 2800, Ti--B--N films 2750, and Ti--Al--B--N films 1650

  5. Boron carbide-based ceramics via polymer route synthesis

    International Nuclear Information System (INIS)

    Boron carbide is a ceramic material with excellent high temperature physical properties. As compared to conventional techniques, the preparation of boron carbide from polymeric precursors is attractive as this technique offers a number of unique advantages. In this paper, the screening of polymeric precursors to boron carbide will be discussed. Two promising boron carbide, carborane containing polymeric precursors have resulted in 60-70 wt.% ceramic yields. The chemistry of polymer synthesis and the transformations from the polymer to amorphous and crystalline boron carbide were investigated with infrared spectroscopy, NMR spectroscopy, thermal analysis, and x-ray diffraction

  6. Determination of carbon and sulphur in boron carbide

    International Nuclear Information System (INIS)

    Boron carbide is used in control rods of nuclear power reactors. The chemical specification for carbon in boron carbide ranges between 15 - 24 wt.% depending upon the grade of boron carbide. Hence carbon in boron carbide is to be determined accurately to find out the stoichiometry. Sulphur, which is present in trace quantities, is also to be determined to find out the purity of boron carbide. Carbon is determined by combustion followed by (i) thermal conductivity detection and (ii) infrared detection. Sulphur is determined by (i) combustion followed by infrared detection and (ii) vacuum combustion extraction - quadrupole mass spectrometry. The results are compared. (author)

  7. Direct evidence of metallic bands in a monolayer boron sheet

    Science.gov (United States)

    Feng, Baojie; Zhang, Jin; Liu, Ro-Ya; Iimori, Takushi; Lian, Chao; Li, Hui; Chen, Lan; Wu, Kehui; Meng, Sheng; Komori, Fumio; Matsuda, Iwao

    2016-07-01

    The search for metallic boron allotropes has attracted great attention in the past decades and recent theoretical works predict the existence of metallicity in monolayer boron. Here, we synthesize the β12-sheet monolayer boron on a Ag(111) surface and confirm the presence of metallic boron-derived bands using angle-resolved photoemission spectroscopy. The Fermi surface is composed of one electron pocket at the S ¯ point and a pair of hole pockets near the X ¯ point, which is supported by the first-principles calculations. The metallic boron allotrope in β12 sheet opens the way to novel physics and chemistry in material science.

  8. Medical chemistry of boron neutron capture agents having pharmacological activity

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a cancer treatment that selectively destroys cancer cells following administering a cancer-selective drug containing stable isotope boron-10 and neutron irradiation. In clinical trial of BNCT, disodium mercaptoundecahydro-closo-dodecaborate (BSH) and p-boronophenylalanine (BPA) have been used, however, development of a new drugs with high cancer selectivity and therapeutic efficiency is expected. Therefore, we review boron-containing drugs as a boron neutron capture agents having pharmacological activity, BNCT research on boron-modified porphyrin derivatives which have photosensitivity and neutron capture activity and our proposed neutron sensitizing agent. (author)

  9. A compact, quasi-monochromatic laser-plasma EUV source based on a double-stream gas-puff target at 13.8 nm wavelength

    Czech Academy of Sciences Publication Activity Database

    Wachulak, P.W.; Bartnik, A.; Fiedorowicz, H.; Feigl, T.; Jarocki, R.; Kostecki, J.; Rudawski, P.; Sawicka, Magdalena; Szczurek, M.; Szczurek, A.; Zawadzki, Z.

    2010-01-01

    Roč. 100, č. 3 (2010), 461-469. ISSN 0946-2171 Institutional research plan: CEZ:AV0Z10100523 Keywords : laser-plasma * EUV source * gas puff target * elliptical multi-layer * mirror * table-top setup Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.239, year: 2010

  10. Inefficiency of high boron concentrations for cell killing in boron neutron capture therapy

    International Nuclear Information System (INIS)

    This study is to investigate the relationship between the cell-killing effect of the 10B(n, α)7Li capture reaction, intracellular boron concentration, and thermal neutron fluence in boron neutron capture therapy using in vitro cell survival based on a clonogenic assay, and biophysical analysis. Our results showed that the cell-killing yield of the 10B(n, α)7Li capture reaction per unit thermal neutron fluence declined with an increase in the intracellular boron concentration above 45 μg/ml 10B. The cell-killing effect was well described using an empirical power function of the intracellular boron concentration, with exponent 0.443. Knowledge of this effect will help in the optimization of BNCT. (author)

  11. Structural and biochemical impact of C8-aryl-guanine adducts within the NarI recognition DNA sequence: influence of aryl ring size on targeted and semi-targeted mutagenicity

    OpenAIRE

    Sproviero, Michael; Verwey, Anne M.R.; Rankin, Katherine M.; Witham, Aaron A.; Soldatov, Dmitriy V.; Richard A. Manderville; Fekry, Mostafa I.; Sturla, Shana J.; Sharma, Purshotam; Wetmore, Stacey D.

    2014-01-01

    Chemical mutagens with an aromatic ring system may be enzymatically transformed to afford aryl radical species that preferentially react at the C8-site of 2′-deoxyguanosine (dG). The resulting carbon-linked C8-aryl-dG adduct possesses altered biophysical and genetic coding properties compared to the precursor nucleoside. Described herein are structural and in vitro mutagenicity studies of a series of fluorescent C8-aryl-dG analogues that differ in aryl ring size and are representative of auth...

  12. CD8+ but not CD4+ T cells require cognate interactions with target tissues to mediate GVHD across only minor H antigens, whereas both CD4+ and CD8+ T cells require direct leukemic contact to mediate GVL

    OpenAIRE

    Matte-Martone, Catherine; Liu, Jinli; Jain, Dhanpat; McNiff, Jennifer; Shlomchik, Warren D.

    2008-01-01

    Whether T-cell antigen receptors (TCR) on donor T cells require direct interactions with major histocompatibility complex class I or class II (MHCI/MHCII) molecules on target cells to mediate graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) is a fundamental question in allogeneic stem-cell transplantation (alloSCT). In MHC-mismatched mouse models, these contacts were not required for GVHD. However, this conclusion may not apply to MHC-matched, multiple minor histocompatibility...

  13. Hydrogenation kinetics in oxidized boron-doped silicon irradiated by keV electrons

    Science.gov (United States)

    Lin, Wallace Wan-Li; Sah, Chih-Tang

    1988-08-01

    Hydrogenation kinetics of boron acceptors in oxidized silicon during and after repeated 8-keV electron irradiation (225-2700-μC/cm2 stresses and 10-168-h interirradiation anneals) at room temperature are reported. Hydrogenation proceeds rapidly during irradiation but continues for many hours after the 8-keV electron beam is removed. Postoxidation process dependencies show that postoxidation and postmetallization annealing processes reduce the hydrogenation effect during the 8-keV electron irradiation, while exposure of the oxide to water prior to aluminum electrode deposition enhances it. The data can be interpreted by our two-reaction model consisting of the hydrogen capture reaction by the boron acceptor and the hydrogen recombination reaction to form hydrogen molecule.

  14. Effect of metal hydrides on the burning characteristics of boron

    International Nuclear Information System (INIS)

    Highlights: • The effect of some metal hydrides on the burning characteristics of boron is studied for the first time. • We are the first to conduct a TG experiment on boron samples at high temperatures (a maximum of 1750 °C). • The thermal reaction process of boron is firstly divided into five stages according to the weight gain rate of the sample. • Specific values of metal hydrides on ignition delay time and combustion intensity of boron are obtained. - Abstract: In this study, the effect of four metal hydrides on the burning characteristics of boron was investigated. Thermogravimetric experiment results show that the thermal reaction process of boron samples can be divided into five stages. The thermal reactions of boron can be significantly promoted with LiH, which can reduce the initial temperature of the first violent reaction stage by ∼140 °C. The starting temperature of the post-reaction stage also decreases by ∼260 °C. The results of the laser ignition experiment suggest that all four metal hydrides can promote boron burning. Nonetheless, different metal hydrides display varied promotional effects. Among the studied hydrides, LiH is the most effective additive and shortens the ignition delay time of boron by ∼34.1%. Moreover, it enhances the combustion intensity of boron by ∼117.6%. The other three metal hydrides (CaH2, TiH2, and ZrH2) can also contribute to boron burning

  15. Removal properties of dissolved boron by glucomannan gel.

    Science.gov (United States)

    Oishi, Kyoko; Maehata, Yugo

    2013-04-01

    Boron ions have long been known to form complexes with the cis-diol group of a polysaccharide. Konjac glucomannan (KGM) which is one of polysaccharides was used to remove dissolved boron in this study. KGM forms a complex with boron, but does not remove boron from contaminated waters as well as other polysaccharides because of its high water solubility. Therefore, the removal efficiencies of dissolved boron were examined using both an insoluble KGM gel and KGM semi-gel. The former did not remove dissolved boron, but the latter did. The difference in the ability of boron removal was due to the presence of diol group inside. KGM loses free diol group during the process of gelation. On the other hand, the semi-gel gelated only surface layer in water has diol group inside. The boron removal capacity of the semi-gel was highest at pHs⩾11, when the boron species is present as B(OH)4(-). The capacity was slightly increased by the addition of Al, Ca and Mg under high pH conditions. This was due to co-precipitation of boron with Ca dissolved from the semi-gel. The boron adsorbed to the semi-gel easily was desorbed under low pH conditions and the hysteresis was not found. PMID:23260255

  16. Relationship Between Soil Boron Adsorption Kinetics and Rape Plant Boron Response

    Institute of Scientific and Technical Information of China (English)

    ZHUDUANWEI; PIMEIMEI; 等

    1997-01-01

    The boron adsorption kinetic experiment in soil by means a flow displacement technique showed that the kinetic data could be described with some mathematic equations.The average values of the coorealtion coefficeint for zero-order,first-order,parabolic diffusion ,Elovich,power function and eponential equations were 0.957,0.982,0.981,0.984,0.981 and 0.902 ,respectively,The correlation between adsorbed boron or its other expression form and time were the highest for first-order ,parabloic diffusion Elovich,and pwer function equations,the second for the zeroorder equation,and the tlowest for the exponential equation.The parabloic diffusion equation fitted well the expermiental results,with the least standard error among the six kinetic equation,showing that the monvemetn of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed.The boron content of rape seedling obtained from soil cultvation was correlated with the rate constants of the kinetic equations.The constants of first-order ,parabloic diffusion,and exponential equaitions were significanlty correlated with the boron content of the crop of NPK treatment at a 95% probaility level ,with correation coeffecients being 0.686,0.691 and 0.64 and 0.641,respectively.In the case of zero-order equation,it Was significant at 99% probability level(r=0.736),These results showed that the adsorption kinetic constants of soil boron were closely related with the rape plant response to boron.

  17. The structure and local chemical properties of boron-terminated tetravacancies in hexagonal boron-nitride

    OpenAIRE

    Cretu, Ovidiu; Lin, Yung-Chang; Koshino, Masanori; Tizei, Luiz H. G.; Liu, Zheng; Suenaga, Kazutomo

    2014-01-01

    Imaging and spectroscopy performed in a low-voltage scanning transmission electron microscope (LV-STEM) are used to characterize the structure and chemical properties of boron-terminated tetravacancies in hexagonal boron nitride (h-BN). We confirm earlier theoretical predictions about the structure of these defects and identify new features in the electron energy-loss spectra (EELS) of B atoms using high resolution chemical maps, highlighting differences between these areas and pristine sampl...

  18. A colorimetric determination of boron in biological sample for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    The boron neutron capture therapy (BNCT) has shown better prognosis in the treatment of glyemas and gluoblastomas grade III and IV than other therapies. During the treatment the levels of Na210B12H11SH must be known in several compartiments of the organism and with this purpose the method of colorimetric determination of boron using curcumine was established. This method is simple, reprodutible and adequate sensitivity for this control. (author)

  19. Effects of fluorotelomer alcohol 8:2 FTOH on steroidogenesis in H295R cells: Targeting the cAMP signalling cascade

    International Nuclear Information System (INIS)

    Previous studies have demonstrated that perfluorinated chemicals (PFCs) can affect reproduction by disruption of steroidogenesis in experimental animals. However, the underlying mechanism(s) of this disruption remain unknown. Here we investigated the effects and mechanisms of action of 1H, 1H, 2H, 2H-perfluoro-decan-1-ol (8:2 FTOH) on steroidogenesis using a human adrenocortical carcinoma cell line (H295R) as a model. H295R cells were exposed to 0, 7.4, 22.2 or 66.6 μM 8:2 FTOH for 24 h and productions of progesterone, 17α-OH-progesterone, androstenedione, testosterone, deoxycorticosterone, corticosterone and cortisol were quantified by HPLC-MS/MS. With the exception of progesterone, 8:2 FTOH treatment significantly decreased production of all hormones in the high dose group. Exposure to 8:2 FTOH significantly down-regulated cAMP-dependent mRNA expression and protein abundance of several key steroidogenic enzymes, including StAR, CYP11A, CYP11B1, CYP11B2, CYP17 and CYP21. Furthermore, a dose-dependent decrease of cellular cAMP levels was observed in H295R cells exposed to 8:2 FTOH. The observed responses are consistent with reduced cellular cAMP levels. Exposure to 8:2 FTOH resulted in significantly less basal (+ GTP) and isoproterenol-stimulated adenylate cyclase activities, but affected neither total cellular ATP level nor basal (-GTP) or NaF-stimulated adenylate cyclase activities, suggesting that inhibition of steroidogenesis may be due to an alteration in membrane properties. Metabolites of 8:2 FTOH were not detected by HPLC-MS/MS, suggesting that 8:2 FTOH was not metabolized by H295R cells. Overall, the results show that 8:2 FTOH may inhibit steroidogenesis by disrupting the cAMP signalling cascade.

  20. Effects of boron number per unit volume on the shielding properties of composites made with boron ores form China

    International Nuclear Information System (INIS)

    The total macroscopic removal cross sections, deposited energies and the absorbed doses of three new shielding composites loaded with specific boron-rich slag, boron concentrate ore and boron mud of China for 252Cf neutron source were investigated by experimental and Monte Carlo calculation. The results were evaluated by boron mole numbers per unit volume in composites. The half value layers of the composites were calculated and compared with that of Portland concrete, indicating that ascending boron mole numbers per unit volume in the composites can enhance the shielding properties of the composites for 252Cf neutron source. (authors)

  1. Rapid mass-spectrometric determination of boron isotopic distribution in boron carbide.

    Science.gov (United States)

    Rein, J E; Abernathey, R M

    1972-07-01

    Boron isotopic ratios are measured in boron carbide by thermionic ionization mass spectrometry with no prior chemical separation. A powder blend of boron carbide and sodium hydroxide is prepared, a small portion is transferred to a tantalum filament, the filament is heated to produce sodium borate, and the filament is transferred to the mass spectrometer where the(11)B/(10)B ratio is measured, using the Na(2)BO(2)(+) ion. Variables investigated for their effect on preferential volatilization of (10)B include the sodium hydroxide-boron carbide ratio and the temperature and duration of filament heating. A series of boron carbide pellets containing natural boron, of the type proposed for the control rods of the Fast Flux Test Facility reactor, were analysed with an apparently unbiased result of 4.0560 for the (11)B/(10)B ratio (standard deviation 0.0087). The pellets contained over 3% metal impurities typically found in this material. Time of analysis is 45 min per sample, with one analyst. PMID:18961131

  2. Coadsorption of lanthanum with boron and gadolinium with boron on Mo(1 1 0)

    Science.gov (United States)

    Magkoev, Tamerlan T.; Vladimirov, Georgij G.; Rump, Gennadij A.

    2008-05-01

    Submonolayer to multilayer coadsorption of lanthanum (La) with boron (B) and gadolinium (Gd) with boron on the surface of Mo(1 1 0) has been studied by means of Auger electron spectroscopy (AES), electron energy loss spectroscopy (EELS) and work function ( ϕ) measurements. The equilibrium state of double adsorbate systems achieved either by adsorption of rare-earth metal (REM) on boron precovered Mo(1 1 0) surface held at room temperature or after moderate annealing of the system with opposite order of adsorption (B on REM films) is the layer which is the inhomogeneous mixture of boron and REM atoms with preferential concentration of boron in the surface area of the mixed film. The work function of such films even at REM to boron concentration ratio much higher than 1/6 are very close to the values of corresponding bulk LaB 6 and GdB 6, favoring assumption of surface rearrangement as the dominant reason of high electron emission efficiency of hexaborides. Almost total similarity of the results for La-B and Gd-B systems can be viewed as the consequence of weak participation of Gd f-electrons in determining the thermionic properties of corresponding double layers.

  3. Multi-dimensional boron transport modeling in subchannel approach: Part II. Validation of CTF boron tracking model and adding boron precipitation model

    International Nuclear Information System (INIS)

    Highlights: • Validation of implemented multi-dimensional subchannel boron transport model. • Extension of boron transport model to entrained droplets. • Implementation of boron precipitation model. • Testing of the boron precipitation model under transient condition. - Abstract: The risk of small-break loss of coolant accident (SB-LOCA) and other reactivity initiated transients caused by boron dilution in the light water reactors (LWRs), and the complications of tracking the soluble boron concentration experimentally inside the primary coolant have stimulated the interest in computational studies for accurate boron tracking simulations in nuclear reactors. In Part I of this study, the development and implementation of a multi-dimensional boron transport model with modified Godunov scheme based on a subchannel approach within the COBRA-TF (CTF) thermal-hydraulic code was presented. The modified Godunov scheme approach with a physical diffusion term was determined to provide the most accurate and precise solution. Current paper extends these conclusions and presents the model validation studies against experimental data from the Rossendorf coolant mixing model (ROCOM) test facility. In addition, the importance of the two-phase flow characteristics in modeling boron transient are emphasized, especially during long-term cooling period after the loss of coolant accident (LOCA) condition in pressurized water reactors (PWRs). The CTF capabilities of boron transport modeling are further improved based on the three-field representation of the two-phase flow utilized in the code. The boron transport within entrained droplets is modeled, and a model for predicting the boron precipitation under transient conditions is developed and tested. It is aimed to extend the applicability of CTF to reactor transient simulations, and particularly to a large-break loss of coolant accident (LB-LOCA) analysis

  4. Reaction cross sections of intermediate energy sup 3 He-particles on targets from sup 9 Be to sup 2 sup 0 sup 8 Pb

    CERN Document Server

    Ingemarsson, A; Auce, A; Carlson, R F; Cowley, A A; Cox, A J; Förtsch, S V; Johansson, R; Karlson, B R; Lantz, M; Peavy, J; Stander, J A; Steyn, G F; Tibell, G

    2001-01-01

    Reaction cross sections for sup 3 He-particles have been measured for sup 9 Be, sup 1 sup 2 C, sup 1 sup 6 O, sup 2 sup 8 Si, sup 4 sup 0 Ca, sup 5 sup 8 sup , sup 6 sup 0 Ni, sup 1 sup 1 sup 2 sup , sup 1 sup 1 sup 6 sup , sup 1 sup 1 sup 8 sup , sup 1 sup 2 sup 0 sup , sup 1 sup 2 sup 4 Sn, and sup 2 sup 0 sup 8 Pb at 96, 138 and 167 MeV. The results are compared with predictions from optical model calculations using phenomenological and global optical potentials. The behaviour of the wavefunctions and of the contributions to the reaction cross sections from different regions in the nucleus is investigated. Comparisons are also made with results for alpha-particles obtained in the same energy region.

  5. P13.09ADVANCES IN CLINICAL APPLICATION OF BORON NEUTRON CAPTURE THERAPY (BNCT) IN GLIOBLASTOMA

    Science.gov (United States)

    Detta, A.; Cruickshank, G.C.; Green, S.; Lockyer, N.P.; Ngoga, D.; Ghani, Z.; Phoenix, B.

    2014-01-01

    BNCT is a biologically targeted form of enhanced cellular radiotherapy where preferential accumulation of boron in the cancerous as opposed to adjacent normal cells is able to interact with incident neutrons to cause irreversible alpha particle DNA damage. The key to the implementation of this potentially powerful and selective therapy is the delivery of at least 30ppm 10B within the tumour tissue while minimising superfluous 10B in healthy tissue. It is thus an elegant technique for treating infiltrating tumours such as diffuse gliomas. In order to assess its clinical potential we carried out a pharmacokinetic study in glioblastoma patients where we sought to determine the optimal route of delivering a new formulation of the boronated drug (p-boronophenylalanine, BPA), its pharmacokinetic behaviour, toxicity profile, and cellular uptake. Using a number of analytical techniques, including inductively-coupled plasma mass spectrometry, secondary ion mass spectrometry (SIMS) and immunohistochemistry (IHC), boron was measured at various times in blood, urine, cerebrospinal fluid, extracellular fluid (ECF), and tumour-related solid tissue spanning 0.5 h pre- and up to 48 h post-BPA infusion in newly-diagnosed patients (n = 10). Blood was sampled through a central catheter whilst the ECF was sampled by parenchymal microdialysis catheters, placed remotely from the tumour site. Urine was collected over the same time period. Tumour and brain-around tumour (BAT) tissue was sampled stereotactically at 2.5 h and 3.5 h post-infusion. IHC expression levels of the BPA transporter molecule, L-amino acid transporter 1 (LAT-1), were recorded as % LAT-1 positive cells, and cellular boron levels were estimated as spatially resolved pixels in normalised-to-C+ isotopic SIMS images of the biopsies. There were no toxicity-related issues with this new formulation of BPA given at 375 mg/kg as a 2 h intravenous or intracarotid infusion with or without pre-infusion mannitol-induced BBB

  6. Implication of extracellular zinc exclusion by recombinant human calprotectin (MRP8 and MRP14 from target cells in its apoptosis-inducing activity

    Directory of Open Access Journals (Sweden)

    Satoru Yui

    2002-01-01

    Full Text Available Background: Calprotectin is a calcium-binding and zinc-binding protein complex that is abundant in the cytosol of neutrophils. This factor is composed of 8 and 14 kDa subunits, which have also been termed migration inhibitory factor-related proteins MRP8 and MRP14. We previously reported that rat calprotectin purified from inflammatory neutrophils induces apoptosis of various tumor cells or normal fibroblasts in a zinc-reversible manner.

  7. PWR core response to boron dilution transient

    International Nuclear Information System (INIS)

    This paper illustrates the steps followed in order to set up a tool (composed of a plant model and of a procedure) that allows accounting for boron reactivity feedbacks during plant transients. The procedure that has been developed allows to find out the values of the boron feedback coefficients, given the differential boron worth, and to properly initialize the Thermal Hydraulic and the Neutronic (TH/NEU) system. Once the tool has been developed, it has been used to analyze different scenarios, resulting from deborated water injection from the reactor make-up system. The most important parameter, during this Reactivity Insertion Accidents (RIAs), is the Energy Released to the Fuel (ERF) and it has been monitored, in order to identify the situations when the fuel might be damaged (ERF > 250 kJ/kg, for high burnup fuel). The analyses have been performed using the RELAP5-3D computer code. The conclusion of the study is that the limited capability of modeling mixing phenomena provided by most common plant codes (such as RELAP5-3D) is not suitable to perform BE analyses of RIAs, since those accidents are so sensitive to boron concentration changes that the effect of uncertainties cannot be neglected. The use of Computational Fluid Dynamics (CFD) codes could reduce uncertainties enough to perform BE analyses and thus it should be recommended. (author)

  8. Pechmann Reaction Promoted by Boron Trifluoride Dihydrate

    Directory of Open Access Journals (Sweden)

    J. Mezger

    2005-08-01

    Full Text Available The Pechmann reaction of substituted phenols 1a-e with methyl acetoacetate (2 can be activated by boron trifluoride dihydrate (3 to give the corresponding 4-methyl- coumarin derivatives 4a-e in excellent yield (98-99 %.

  9. New insight into pecan boron nutrition

    Science.gov (United States)

    Alternate bearing by individual pecan [Carya illinoinensis (Wangenh.) K. Koch] trees is problematic for nut producers and processors. There are many unknowns regarding alternate bearing physiology, such as the relationship between boron and fruit set, nutmeat quality, and kernel maladies. Evidence...

  10. Influence of pollution of boron chlorinity ratio

    Digital Repository Service at National Institute of Oceanography (India)

    Narvekar, P.V.; Zingde, M.D.

    Presence of boron in domestic wastewater has resulted in high B/CI ratio at some locations in the coastal water around Bombay. A widest range (0.215-0.281) of B/CI was observed at a location with high influence of wastewater release. The mean B...

  11. Boron carbide morphology changing under purification

    Science.gov (United States)

    Rahmatullin, I. A.; Sivkov, A. A.

    2015-10-01

    Boron carbide synthesized by using coaxial magnetoplasma accelerator with graphite electrodes was purified by two different ways. XRD-investigations showed content changing and respectively powder purification. Moreover TEM-investigations demonstrated morphology changing of product under purification that was discussed in the work.

  12. Boron carbide synthesis at plasma spray process

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Brožek, Vlastimil; Hofman, R.

    Bari : Department of Chemistry, University of Bari, 2003 - (d'Agostino, R.; Favia, P.; Fracassi, F.; Palumbo, F.). s. 631 [International Symposium on Plasma Chemistry/16th./. 22.06.2003-27.06.2003, Taormina] Institutional research plan: CEZ:AV0Z2043910 Keywords : boron carbide , plasma spray process Subject RIV: BL - Plasma and Gas Discharge Physics

  13. Joining of boron carbide using nickel interlayer

    International Nuclear Information System (INIS)

    Carbide ceramics such as boron carbide due to their unique properties such as low density, high refractoriness, and high strength to weight ratio have many applications in different industries. This study focuses on direct bonding of boron carbide for high temperature applications using nickel interlayer. The process variables such as bonding time, temperature, and pressure have been investigated. The microstructure of the joint area was studied using electron scanning microscope technique. At all the bonding temperatures ranging from 1150 to 1300degC a reaction layer formed across the ceramic/metal interface. The thickness of the reaction layer increased by increasing temperature. The strength of the bonded samples was measured using shear testing method. The highest strength value obtained was about 100 MPa and belonged to the samples bonded at 1250 for 75 min bonding time. The strength of the joints decreased by increasing the bonding temperature above 1250degC. The results of this study showed that direct bonding technique along with nickel interlayer can be successfully utilized for bonding boron carbide ceramic to itself. This method may be used for bonding boron carbide to metals as well.

  14. Boron nitride nanosheets reinforced glass matrix composites

    Czech Academy of Sciences Publication Activity Database

    Saggar, Richa; Porwal, H.; Tatarko, P.; Dlouhý, Ivo; Reece, M. J.

    2015-01-01

    Roč. 114, SEP (2015), S26-S32. ISSN 1743-6753 R&D Projects: GA MŠk(CZ) 7AMB14SK155 EU Projects: European Commission(XE) 264526 Institutional support: RVO:68081723 Keywords : Boron nitride nanosheets * Borosilicate glass * Mechanical properties Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.163, year: 2014

  15. The manufacturing method of boron carbide

    International Nuclear Information System (INIS)

    The new method for manufacturing of boron carbide as powder with controlled purity and surface development has been described. The suspension of boric acid aqueous solution and carbon black in alcohol has been homogenized mechanically. Water and alcohol are then evaporated during mixing. After drying homogenous mixture is heated in temperature range of 1270-1870 C during one hour

  16. Novel Boron Based Multilayer Thermal Neutron Detector

    CERN Document Server

    SCHIEBER, M

    2010-01-01

    The detector contains four or more layers of natural Boron absorbing thermal neutrons. Thickness of a layer is 0.4 - 1.2 mg/cm2. The layers are deposited on one or on both sides of a metal surface used as contacts. Between the absorbing layers there are gas-filled gaps 3 - 6 mm thick. Electric field of 100 - 200 V/cm is applied to the gas-filled gaps. Natural Boron contains almost 20% of 10B isotope. When atoms of 10B capture a thermal neutron, nuclear reaction occurs, as a result of which two heavy particles - alpha particle and ion 7Li - from the thin absorber layer are emitted in opposing sides. One of the two particles penetrates into gas-filled gap between Boron layers and ionizes the gas. An impulse of electric current is created in the gas-filled gap actuated by the applied electric field. The impulse is registered by an electronic circuit. We have made and tested detectors containing from two to sixteen layers of natural Boron with an efficiency of thermal neutron registration from 2.9% to 12.5% accor...

  17. Targeted alpha-radionuclide therapy of functionally critically located gliomas with 213Bi-DOTA-[Thi8,Met(O2)11]-substance P: a pilot trial

    International Nuclear Information System (INIS)

    Functionally critically located gliomas represent a challenging subgroup of intrinsic brain neoplasms. Standard therapeutic recommendations often cannot be applied, because radical treatment and preservation of neurological function are contrary goals. The successful targeting of gliomas with locally injected beta radiation-emitting 90Y-DOTAGA-substance P has been shown previously. However, in critically located tumours, the mean tissue range of 5 mm of 90Y may seriously damage adjacent brain areas. In contrast, the alpha radiation-emitting radionuclide 213Bi with a mean tissue range of 81 μm may have a more favourable toxicity profile. Therefore, we evaluated locally injected 213Bi-DOTA-substance P in patients with critically located gliomas as the primary therapeutic modality. In a pilot study, we included five patients with critically located gliomas (WHO grades II-IV). After diagnosis by biopsy, 213Bi-DOTA-substance P was locally injected, followed by serial SPECT/CT and MR imaging and blood sampling. Besides feasibility and toxicity, the functional outcome was evaluated. Targeted radiopeptide therapy using 213Bi-DOTA-substance P was feasible and tolerated without additional neurological deficit. No local or systemic toxicity was observed. 213Bi-DOTA-substance P showed high retention at the target site. MR imaging was suggestive of radiation-induced necrosis and demarcation of the tumours, which was validated by subsequent resection. This study provides proof of concept that targeted local radiotherapy using 213Bi-DOTA-substance P is feasible and may represent an innovative and effective treatment for critically located gliomas. Primarily non-operable gliomas may become resectable with this treatment, thereby possibly improving the prognosis. (orig.)

  18. BCM6: New Generation of Boron Meter

    International Nuclear Information System (INIS)

    Full text of publication follows: Rolls-Royce has developed a new generation of boron meter, based on more than 30 years of experience. The Rolls-Royce BCM6 boron meter provides Nuclear Power Plant (NPP) operators with the boron concentration of the primary circuit. The meter provides continuous and safe measurements with no manual sampling and no human contact. In this paper, technical features, advantages and customer benefits of the use of the new generation of Rolls-Royce BCM6 boron meter will be detailed. Values and associated alarms are provides over different media: 4-20 mA outputs, relays, displays in the main control room and in the chemical lab, and digital links. A special alarm avoids unexpected homogeneous dilution of the primary circuit, which is a critical operational parameter. The Rolls-Royce BCM6 boron meter is fully configurable over a set of parameters allowing adaptation to customer needs. It has a differential capability, thus eliminating neutronic noise and keeping measurements accurate, even in the case of fuel clad rupture. Measurements are accurate, reliable, and have a quick response time. Equipment meets state-of-the-art qualification requests. Designed in 2008, the BCM6 boron meter is the newest equipment of Rolls-Royce boron meters product line. It has been chosen to equip the French EPR NPP and complies with the state-of-the-art of the technology. Rolls-Royce has more than 30 years of experience in Instrumentation and Controls with more than 75 NPP units operating worldwide. All of this experience return has been put in this new generation of equipment to provide the customer with the best operation. About Rolls-Royce Rolls-Royce is a global business providing integrated power systems for use on land, at sea and in the air. The Group has a balanced business portfolio with leading market positions. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design

  19. Boron carbide nanowires: Synthesis and characterization

    Science.gov (United States)

    Guan, Zhe

    Bulk boron carbide has been widely used in ballistic armored vest and the property characterization has been heavily focused on mechanical properties. Even though boron carbides have also been projected as a promising class of high temperature thermoelectric materials for energy harvesting, the research has been limited in this field. Since the thermal conductivity of bulk boron carbide is still relatively high, there is a great opportunity to take advantage of the nano effect to further reduce it for better thermoelectric performance. This dissertation work aims to explore whether improved thermoelectric performance can be found in boron carbide nanowires compared with their bulk counterparts. This dissertation work consists of four main parts. (1) Synthesis of boron carbide nanowires. Boron carbide nanowires were synthesized by co-pyrolysis of diborane and methane at low temperatures (with 879 °C as the lowest) in a home-built low pressure chemical vapor deposition (LPCVD) system. The CVD-based method is energy efficient and cost effective. The as-synthesized nanowires were characterized by electron microscopy extensively. The transmission electron microscopy (TEM) results show the nanowires are single crystalline with planar defects. Depending on the geometrical relationship between the preferred growth direction of the nanowire and the orientation of the defects, the as-synthesized nanowires could be further divided into two categories: transverse fault (TF) nanowires grow normal to the defect plane, while axial fault (AF) ones grow within the defect plane. (2) Understanding the growth mechanism of as-synthesized boron carbide nanowires. The growth mechanism can be generally considered as the famous vapor-liquid-solid (VLS) mechanism. TF and AF nanowires were found to be guided by Ni-B catalysts of two phases. A TF nanowire is lead by a hexagonal phase catalyst, which was proved to be in a liquid state during reaction. While an AF nanowires is catalyzed by a

  20. Removal of boron from ceramic industry wastewater by adsorption-flocculation mechanism using palm oil mill boiler (POMB) bottom ash and polymer.

    Science.gov (United States)

    Chong, Mei Fong; Lee, Kah Peng; Chieng, Hui Jiun; Syazwani Binti Ramli, Ili Izyan

    2009-07-01

    Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation-coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption-flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH=8.0, dosage=40 g bottom ash/300 ml wastewater, residence time=1h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer=100 mg/L, dosage of AP 120 C anionic polymer=50 mg/L, mixing speed=200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were

  1. Geochemical study of boron isotopes in the process of loess weathering

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Zhiqi; (

    2003-01-01

    [1]Palmer, M. R., Swihart, G. H., Boron isotope geochemistry: An overview, in Rev. Mineral 33, Boron Mineralogy, Petrology and Geochemistry (eds. Grew, E. S., Anovitz, L. M.), Washington, D. C.: Mineral Soc. Am., 1996, 709-744.[2]Chaussidon, M., Albarède, F., Secular boron isotope variations in the continental crust: An ion microprobe study, Earth Planet Sci. Lett., 1992, 108: 229-241.[3]Spivack, A. J., Edmond, J. M., Boron isotope exchange between seawater and the oceanic crust, Geochim. Cosmochim. Acta, 1987, 51: 1033-1043.[4]Vengosh, A., Chivas, A. R., Mcculloch, M. T. et al., Boron isotope geochemistry of Australian salt lakes, Geochim. Cosmochim. Acta, 1991, 55: 2591-2606.[5]Xiao, Y. K., Sun, D. P., Wang, Y. H. et al., Boron isotopic compositions of brine, sediments and source water in Da Qaidam Lake, Qinghai, China, Geochim Cosmochim Acta, 1992,56: 1561-1568.[6]Mcmullen, C. C., Cragg, C. B., Thode, H. G., Absolute rations of 11B/10B in Searles Lake borax, Geochim. Cosmochim. Acta, 1961, 23: 147-150.[7]Palmer, M. R., Sturchio, N. C., The boron isotope systematics of the Yellowstone National Park (Wyoming) hydrothermal system: A reconnaissance, Geochim. Cosmochim. Acta, 1990, 54: 2811-2815.[8]Arndsson, S., Andrèsdèttir, A., Processes controlling the distribution of boron and chlorine in natural waters in Iceland, Geochim. Cosmochim. Acta, 1995, 59: 4125-4146.[9]Aggarwal, J. K., Palmer, M. R., Bullen, T. D. et al., The boron isotope systematics of Iceland geothermal waters: 1. Meteoric water charged systems, Geochim. Cosmochim. Acta, 2000, 64: 579-585.[10]Spivack, A. J., Palmer, M. R., Edmond, J. M., The sedimentary cycle of the boron isotopes, Geochim. Cosmochim. Acta, 1987, 51: 1939-1949.[11]Liu Yingjun, Cao Liming, Li Zhaolin et al., Element Geochemistry (in Chinese), Beijing: Science Press, 1984, 422-428.[12]Schwarcz, H. P., Agyei, E. K., Mcmullen, C. C., Boron isotopic fractionation during clay adsorption

  2. Effects of decoy molecules targeting NF-kappaB transcription factors in Cystic fibrosis IB3-1 cells: recruitment of NF-kappaB to the IL-8 gene promoter and transcription of the IL-8 gene.

    Science.gov (United States)

    Finotti, Alessia; Borgatti, Monica; Bezzerri, Valentino; Nicolis, Elena; Lampronti, Ilaria; Dechecchi, Maria; Mancini, Irene; Cabrini, Giulio; Saviano, Michele; Avitabile, Concetta; Romanelli, Alessandra; Gambari, Roberto

    2012-01-01

    One of the clinical features of cystic fibrosis (CF) is a deep inflammatory process, which is characterized by production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against CF to reduce the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. In order to demonstrate that TFD against NF-kappaB interferes with the NF-kappaB pathway we proved, by chromatin immunoprecipitation (ChIP) that treatment with TFD oligodeoxyribonucleotides of cystic fibrosis IB3-1 cells infected with Pseudomonas aeruginosa leads to a decrease occupancy of the Il-8 gene promoter by NF-kappaB factors. In order to develop more stable therapeutic molecules, peptide nucleic acids (PNAs) based agents were considered. In this respect PNA-DNA-PNA (PDP) chimeras are molecules of great interest from several points of view: (1) they can be complexed with liposomes and microspheres; (2) they are resistant to DNases, serum and cytoplasmic extracts; (3) they are potent decoy molecules. By using electrophoretic mobility shift assay and RT-PCR analysis we have demonstrated that (1) the effects of PDP/PDP NF-kappaB decoy chimera on accumulation of pro-inflammatory mRNAs in P.aeruginosa infected IB3-1 cells reproduce that of decoy oligonucleotides; in particular (2) the PDP/PDP chimera is a strong inhibitor of IL-8 gene expression; (3) the effect of PDP/PDP chimeras, unlike those of ODN-based decoys, are observed even in the absence of protection with lipofectamine. These informations are of great impact, in our opinion, for the development of stable molecules to be used in non-viral gene therapy of cystic fibrosis. PMID:22772035

  3. Synthesis and radiation response of BCON: a graphene oxide and hexagonal boron nitride hybrid

    Science.gov (United States)

    Bhimanapati, Ganesh R.; Wetherington, Maxwell; Mahabir, Shawn; Robinson, Joshua A.

    2016-06-01

    Since graphene, there has been a focus on several two-dimensional material systems (e.g. boron nitride, borocarbon nitride (BCN), transition-metal dichalcogenides) that provide an even wider array of unique chemistries and properties to explore future applications. Specifically, tailoring graphene/boron nitride heterostructures—which can theoretically retain the character of a single-atom thick sheet, withstand large physical strains, are easily functionalized, and have entirely different optical and mechanical properties compared to graphene—can provide the foundation for entirely new research avenues. In recent years, it has been shown that because of the similar crystal structure, carbon, boron, and nitrogen can co-exist as atomic sheets in a layered structure. We have developed a facile method of integrating boron nitride (hBN) and graphene oxide (GO) via chemical exfoliation which we refer to as BCON. The study of the stability of this material at different pH conditions indicates a stable and a uniform solution is achievable at pH 4–8. X-Ray Photoelectron Spectroscopy helped to identify the new bonds which indicated the formation of BCON linkage. Further, an in situ XPS technique was used to understand the chemical changes while exposing it to ionization radiation specially focusing on the C/O ratio. It was observed that even with a very low energy source, this material is highly sensitive to ionizing radiation, such as neutron, alpha and beta particles.

  4. Laser Ablation Molecular Isotopic Spectrometry: Parameter influence on boron isotope measurements

    International Nuclear Information System (INIS)

    Laser Ablation Molecular Isotopic Spectrometry (LAMIS) was recently reported for optical isotopic analysis of condensed samples in ambient air and at ambient pressure. LAMIS utilizes molecular emissions which exhibit larger isotopic spectral shits than in atomic transitions. For boron monoxide 10BO and 11BO, the isotopic shifts extend from 114 cm-1 (0.74 nm) to 145-238 cm-1 (5-8 nm) at the B2Σ+ (v = 0) → X2Σ+ (v = 2) and A2Πi (v = 0) → X2Σ+ (v = 3) transitions, respectively. These molecular isotopic shifts are over two orders of magnitude larger than the maximum isotopic shift of approximately 0.6 cm-1 in atomic boron. This paper describes how boron isotope abundance can be quantitatively determined using LAMIS and how atomic, ionic, and molecular optical emission develops in a plasma emanating from laser ablation of solid samples with various boron isotopic composition. We demonstrate that requirements for spectral resolution of the measurement system can be significantly relaxed when the isotopic abundance ratio is determined using chemometric analysis of spectra. Sensitivity can be improved by using a second slightly delayed laser pulse arriving into an expanding plume created by the first ablation pulse.

  5. IMPROVEMENT OF TYPE IV CRACKING RESISTANCE OF 9Cr HEAT RESISTING STEEL WELDMENT BY BORON ADDITION

    Institute of Scientific and Technical Information of China (English)

    M.Tabuchi; M.Kondo; T.Watanabe; H.Hongo; F.Yin; F.Abe

    2004-01-01

    Creep lives of high Cr ferritic heat resisting steel weldments decrease due to Type IV fracture, which occurs as a result of formation and growth of creep voids and cracks on grain boundaries in fine-grained heat affected zone (HAZ). Because boron is considered to suppress the coarsening of grain boundary precipitates and growth of creep voids, we have investigated the effect of boron addition on the creep properties of 9Cr steel weldments. Four kinds of 9Cr3W3CoVNb steels with boron content varying from 4.7×10-5 to 1.8×10-4 and with nitrogen as low as 2.0×10-5 were prepared.The steel plates were welded by gas tungsten arc welding and crept at 923K. It was found that the microstructures of HAZ were quite different from those of conventional high Cr steels such as P91 and P92, namely the fine-grained HAZ did not exist in the present steel weldments. Boron addition also has the effect to suppress coarsening of grain boundary carbides in HAZ during creep. As a result of these phenomena,the welded joints of present steels showed no Type IV fractures and much better creep lives than those of conventional steels.

  6. Determination of boron in graphite by a wet oxidation decomposition/curcumin photometric method

    International Nuclear Information System (INIS)

    The wet oxidation decomposition of graphite materials has been studied for the accurate determination of boron using a curcumin photometric method. A graphite sample of 0.5 g was completely decomposed with a mixture of 5 ml of sulfuric acid, 3 ml of perchloric acid, 0.5 ml of nitric acid and 5 ml of phosphoric acid in a silica 100 ml Erlenmeyer flask fitted with an air condenser at 200degC. Any excess of perchloric and nitric acids in the solution was removed by heating on a hot plate at 150degC. Boron was distilled with methanol, and then recovered in 10 ml of 0.2 M sodium hydroxide. The solution was evaporated to dryness. To the residue were added curcumin-acetic acid and sulfuric-acetic acid. The mixture was diluted with ethanol, and the absorbance at 555 nm was measured. The addition of 5 ml of phosphoric acid proved to be effective to prevent any volatilization loss of boron during decomposition of the graphite sample and evaporation of the resulting solution. The relative standard deviation was 4-8% for samples with 2 μg g-1 levels of boron. The results on CRMs JAERI-G5 and G6 were in good agreement with the certified values. (author)

  7. Hemorrhage in mouse tumors induced by dodecaborate cluster lipids intended for boron neutron capture therapy

    Directory of Open Access Journals (Sweden)

    Schaffran T

    2014-07-01

    Full Text Available Tanja Schaffran,1 Nan Jiang,1 Markus Bergmann,2,3 Ekkehard Küstermann,4 Regine Süss,5 Rolf Schubert,5 Franz M Wagner,6 Doaa Awad,7 Detlef Gabel1,2,8 1Department of Chemistry, University of Bremen, 2Institute of Neuropathology, Klinikum Bremen-Mitte; 3Cooperative Center Medicine, University of Bremen, 4“In-vivo-MR” AG, FB2, University of Bremen, Bremen, 5Pharmaceutical Technology, University of Freiburg, Freiburg im Breisgau, 6Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II, Technische Unversitaet Muenchen, Garching, Germany; 7Department of Biochemistry, Alexandria University, Alexandria, Egypt; 8School of Engineering and Science, Jacobs University Bremen, Bremen, Germany Abstract: The potential of boron-containing lipids with three different structures, which were intended for use in boron neutron capture therapy, was investigated. All three types of boron lipids contained the anionic dodecaborate cluster as the headgroup. Their effects on two different tumor models in mice following intravenous injection were tested; for this, liposomes with boron lipid, distearoyl phosphatidylcholine, and cholesterol as helper lipids, and containing a polyethylene glycol lipid for steric protection, were administered intravenously into tumor-bearing mice (C3H mice for SCCVII squamous cell carcinoma and BALB/c mice for CT26/WT colon carcinoma. With the exception of one lipid (B-THF-14, the lipids were well tolerated, and no other animal was lost due to systemic toxicity. The lipid which led to death was not found to be much more toxic in cell culture than the other boron lipids. All of the lipids that were well tolerated showed hemorrhage in both tumor models within a few hours after administration. The hemorrhage could be seen by in vivo magnetic resonance and histology, and was found to occur within a few hours. The degree of hemorrhage depended on the amount of boron administered and on the tumor model. The observed unwanted effect of the lipids

  8. Thermal conductivity of polymer composites with oriented boron nitride

    International Nuclear Information System (INIS)

    Highlights: • Thermal conductivity depended on the orientation of BN in the polymer matrices. • Hexagonal boron nitride (BN) particles were treated by C27H27N3O2 and C14H6O8. • Amphiphilic-agent-treated BN particles are more easily oriented in the composite. • BN/PVA composites with C14H6O8-treated BN showed the highest thermal conductivity. • Thermal conductivity of the composites was compared with several theoretical models. - Abstract: Thermal conductivity of boron nitride (BN) with polyvinyl alcohol (PVA) and/or polyvinyl butyral (PVB) was investigated as a function of the degree of BN orientation, the numbers of hydroxyl groups in the polymer matrices and the amphiphilic agents used. The composites with in-plane orientation of BN showed a higher thermal conductivity than the composites with out-of-plane orientation of BN due to the increase of thermal pathway. For a given BN content, the composites with in-plane orientation of BN/PVA showed higher thermal conductivity than the composites with in-plane orientation of BN/PVB. This result could be attributed to the improved degree of orientation of BN, caused by a larger number of hydroxyl groups being present. Those treated with C14H6O8 amphiphilic agent demonstrated a higher thermal conductivity than those treated by C27H27N3O2. The measured thermal conductivity of the composites was compared with that predicted by the several theoretical models

  9. Toll-Like Receptor 2 Targeted Rectification of Impaired CD8⁺ T Cell Functions in Experimental Leishmania donovani Infection Reinstates Host Protection.

    Directory of Open Access Journals (Sweden)

    Syamdas Bandyopadhyay

    Full Text Available Leishmania donovani, a protozoan parasite, causes the disease visceral leishmanisis (VL, characterized by inappropriate CD8+ T-cell activation. Therefore, we examined whether the Toll-like Receptor 2 (TLR2 ligand Ara-LAM, a cell wall glycolipid from non-pathogenic Mycobacterium smegmatis, would restore CD8+ T-cell function during VL. We observed that by efficient upregulation of TLR2 signaling-mediated NF-κB translocation and MAPK signaling in CD8+ T-cells (CD25+CD28+IL-12R+IFN-γR+, Ara-LAM triggered signaling resulted in the activation of T-bet, which in turn, induced transcription favourable histone modification at the IFN-γ, perforin, granzyme-B promoter regions in CD8+ T-cells. Thus, we conclude that Ara-LAM induced efficient activation of effector CD8+ T-cells by upregulating the expression of IFN-γ, perforin and granzyme-B in an NF-κB and MAPK induced T-bet dependent manner in VL.

  10. Decoy oligodeoxyribonucleotides and peptide nucleic acids-DNA chimeras targeting nuclear factor kappa-B: inhibition of IL-8 gene expression in cystic fibrosis cells infected with Pseudomonas aeruginosa.

    Science.gov (United States)

    Gambari, Roberto; Borgatti, Monica; Bezzerri, Valentino; Nicolis, Elena; Lampronti, Ilaria; Dechecchi, Maria Cristina; Mancini, Irene; Tamanini, Anna; Cabrini, Giulio

    2010-12-15

    Cystic fibrosis (CF) is characterized by a deep inflammatory process, with production and release of cytokines and chemokines, among which interleukin 8 (IL-8) represents one of the most important. Accordingly, there is a growing interest in developing therapies against IL-8, with the aim of reducing the excessive inflammatory response in the airways of CF patients. Since transcription factor NF-kappaB plays a critical role in IL-8 expression, the transcription factor decoy (TFD) strategy might be of interest. TFD is based on biomolecules mimicking the target sites of transcription factors (TFs) and able to interfere with TF activity when delivered to target cells. Here, we review the inhibitory effects of decoy oligodeoxyribonucleotides (ODNs) on expression of IL-8 gene and secretion of IL-8 by cystic fibrosis cells infected by Pseudomonas aeruginosa. In addition, the effects of decoy molecules based on peptide nucleic acids (PNAs) are discussed. In this respect PNA-DNA-PNA (PDP) chimeras are interesting: (a) unlike PNAs, they can be complexed with liposomes and microspheres; (b) unlike oligodeoxyribonucleotides (ODNs), they are resistant to DNAses, serum and cytoplasmic extracts; (c) unlike PNA/PNA and PNA/DNA hybrids, they are potent decoy molecules. Interestingly, PDP/PDP NF-kappaB decoy chimeras inhibit accumulation of pro-inflammatory mRNAs (including IL-8 mRNA) in P. aeruginosa infected IB3-1, cells reproducing the effects of decoy oligonucleotides. The effects of PDP/PDP chimeras, unlike ODN-based decoys, are observed even in absence of protection with lipofectamine. Since IL-8 is pivotal in pro-inflammatory processes affecting cystic fibrosis, inhibition of its functions might have a clinical relevance. PMID:20615393

  11. Identification of the Aryl Hydrocarbon Receptor Target Gene TiPARP as a Mediator of Suppression of Hepatic Gluconeogenesis by 2,3,7,8-Tetrachlorodibenzo-p-dioxin and of Nicotinamide as a Corrective Agent for This Effect*

    OpenAIRE

    Diani-Moore, Silvia; Ram, Payal; Li, Xintian; Mondal, Prosenjit; Youn, Dou Yeon; Sauve, Anthony A.; Rifkind, Arleen B.

    2010-01-01

    The environmental toxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin, dioxin) produces diverse toxic effects including a lethal wasting syndrome whose hallmark is suppressed hepatic gluconeogenesis. All TCDD toxicities require activation of the aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor. Whereas the mechanism for AHR induction of target genes is well understood, it is not known how AHR activation produces any TCDD toxicity. This report identifies for the first time ...

  12. The role of various boron precursor on superconducting properties of MgB2/Fe

    Science.gov (United States)

    Safran, S.; Kılıçarslan, E.; Kılıç, A.; Gencer, A.

    2014-09-01

    The superconducting properties of Fe sheathed MgB2 wire has been studied as a function of precursor B powder particle size. The in situ processed MgB2 samples were prepared by means of conventional solid state reaction method with magnesium powder (99.8%, 325 mesh) and three different types of amorphous boron powders (purity; 98.8%, >95% and 91.9%) from two sources, Pavezyum (Turkish supplier) and Sigma Aldrich. The particle sizes of Turkish boron precursor powder were selected between 300 and 800 nm. The structural and magnetic properties of the prepared samples were investigated by means of the X-ray powder diffraction (XRD) and ac susceptibility measurements. The XRD patterns showed that the diffraction peaks for our samples belong to the main phase of the MgB2 diffraction patterns. The highest critical temperature, Tc = 38.4 K was measured for the MgB2 sample which was fabricated by using the 98.8% B. The critical current density of this sample was extracted from the magnetization measurements and Jc = 5.4 × 105 A cm-2 at 5 K and B = 2 T. We found that the sample made by using the 98.8% boron showed almost 2 times higher Jc than that of obtained from 91.9% B powder.

  13. Higher boron rejection with a new TFC forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-07-17

    Due to the stringent limits for boron in drinking and irrigation water, water treatment facilities have to incur additional treatment to remove boron down to a safe concentration. Forward osmosis (FO) is a membrane technology that may reduce the energy required to remove boron present in seawater. In direct FO desalination hybrid systems, fresh water is recovered from seawater using a recoverable draw solution, FO membranes are expected to show high boron rejection. This study focuses on determining the boron rejection capabilities of a new generation thin-film composite (TFC) FO membrane compared to a first generation cellulose triacetate (CTA) FO membrane. The effects of water permeate flux, membrane structure, draw solute charge, and reverse solute flux on boron rejection were determined. For TFC and CTA FO membranes, experiments showed that when similar operating conditions are applied (e.g. membrane type and draw solute type) boron rejection decreases with increase in permeate flux. Reverse draw solute flux and membrane fouling have no significant impact on boron rejection. Compared to the first generation CTA FO membrane operated at the same conditions, the TFC FO membrane showed a 40% higher boron rejection capability and a 20% higher water flux. This demonstrates the potential for boron removal for new generation TFC FO membranes. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  14. ISOBORDAT: An Online Data Base on Boron Isotopes

    International Nuclear Information System (INIS)

    From 1986, boron isotope data in natural substances increased sharply in scientific publications. Analytical difficulties derived from complex geochemical matrices have been faced and interlaboratory calibrations reported in the boron literature. Boron isotopes are nowdays applied to investigate boron origin and migration in natural waters, sources of boron contamination, water-rock interactions and also contribute to water resource management. This is especially important in those areas where boron content exceeds the local regulations for drinking water supply and boron sources need to be identified. ISOBORDAT, an interactive database on boron isotope composition and content in natural waters is presented to the wider community of boron isotope users. The database's structure, scope and applications are reported, along with a discussion on δ11B values obtained in Italian waters. In the database boron data are structured in the following categories: rainwater, rivers, lakes, groundwater and potential contaminants. New categories (medium and high enthalpy fluids from volcanic and geothermal areas) are anticipated. ISOBORDAT aims to be as interactive as possible and will be developed taking into account information and suggestions received. The database is continually undergoing revision to keep pace with continuous data publication. Indications of data that are missing at present are greatly appreciated. (author)

  15. Synthesis and characterization of ammonium phosphate fertilizers with boron

    Directory of Open Access Journals (Sweden)

    ANGELA MAGDA

    2010-07-01

    Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

  16. Resonant transfer excitation followed by X-ray for boron-like ions

    OpenAIRE

    RAMADAN, Hassan

    2011-01-01

    Theoretical cross sections for resonant transfer excitation followed by x-ray emission (RTEX) are calculated for the collisions of some ions in the series of the Boron-like ions with H2 as a target. The calculations have been done for C II, N III, O IV, F V, Ar XIV and Fe XXII ions by folding their dielectronic recombination (DR) cross sections over the momentum distribution (Compton profile) of H2 target gas. Calculations have been performed from both ground and metastable initial st...

  17. Preparation and properties of unidirectional boron nitride fibre reinforced boron nitride matrix composites via precursor infiltration and pyrolysis route

    International Nuclear Information System (INIS)

    Highlights: → BN fibres degrade little when exposed at elevated temperatures. → Precursor infiltration and pyrolysis route is useful to prepare BNf/BN composites. → Few reports have related to the preparation and properties of BNf/BN composites. → BNf/BN composites have desirable high-temperature mechanical properties. → BNf/BN composites have excellent dielectric properties at 2-18 GHz. - Abstract: The unidirectional boron nitride fibre reinforced boron nitride matrix (BNf/BN) composites were prepared via the precursor infiltration and pyrolysis (PIP) route, and the structure, composition, mechanical and dielectric properties were studied. The composites have a high content and fine crystallinity of BN. The density is 1.60 g cm-3 with a low open porosity of 4.66%. The composites display good mechanical properties with the average flexural strength, elastic modulus and fracture toughness being 53.8 MPa, 20.8 GPa and 6.88 MPa m1/2, respectively. Lots of long fibres pull-out from the fracture surface, suggesting a good fibre/matrix interface. As temperature increases, both of the flexural strength and elastic modulus exhibit a decreasing trend, with the lowest values being 36.2 MPa and 8.6 GPa at 1000 deg. C, respectively. The desirable residual ratios of the flexural strength and elastic modulus at 1000 deg. C are 67.3% and 41.3%, respectively. The composites have excellent dielectric properties, with the average dielectric constant and loss tangent being 3.07 and 0.0044 at 2-18 GHz, respectively.

  18. Chemoradiotherapy of cancer using boronated monoclonal antibodies. Progress report, December 1, 1982-November 30, 1983

    International Nuclear Information System (INIS)

    The feasibility was established of using antibodies for the delivery of 10B. Problems faced included 1) preservation of antibody activity following boronation, 2) antigenic receptor site density of the target cells, and 3) delivery of a critical number of 10B atoms per cell. The linkage of a heavily boronated polymeric species to antibody by means of a single functional group allow for the delivery of a large number 10B atoms per antibody molecule without a significant reduction in affinity. Both the polyclonally derived anti-thymocyte globulin (ATG) and the monoclonal anti-colorectal carcinoma antibody (17-1A) recognize antigens that are expressed with a density of approximately 106 epitopes per cell. The major concept that we advance is that just as effective cancer chemotherapy is based on the use of a combination of drugs, similarly a combination of compounds could be employed to deliver the requisite amount of 10B to tumor target cells. This could include compounds such as Na2B12H11Sh together with boronated antibodies directed against tumor associated antigens. (DT)

  19. Comprehensive assessment of sequence variation within the copy number variable defensin cluster on 8p23 by target enriched in-depth 454 sequencing

    Directory of Open Access Journals (Sweden)

    Zhang Xinmin

    2011-05-01

    Full Text Available Abstract Background In highly copy number variable (CNV regions such as the human defensin gene locus, comprehensive assessment of sequence variations is challenging. PCR approaches are practically restricted to tiny fractions, and next-generation sequencing (NGS approaches of whole individual genomes e.g. by the 1000 Genomes Project is confined by an affordable sequence depth. Combining target enrichment with NGS may represent a feasible approach. Results As a proof of principle, we enriched a ~850 kb section comprising the CNV defensin gene cluster DEFB, the invariable DEFA part and 11 control regions from two genomes by sequence capture and sequenced it by 454 technology. 6,651 differences to the human reference genome were found. Comparison to HapMap genotypes revealed sensitivities and specificities in the range of 94% to 99% for the identification of variations. Using error probabilities for rigorous filtering revealed 2,886 unique single nucleotide variations (SNVs including 358 putative novel ones. DEFB CN determinations by haplotype ratios were in agreement with alternative methods. Conclusion Although currently labor extensive and having high costs, target enriched NGS provides a powerful tool for the comprehensive assessment of SNVs in highly polymorphic CNV regions of individual genomes. Furthermore, it reveals considerable amounts of putative novel variations and simultaneously allows CN estimation.

  20. Submicron cubic boron nitride as hard as diamond

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guoduan; Kou, Zili, E-mail: kouzili@scu.edu.cn, E-mail: yanxz@hpstar.ac.cn; Lei, Li; Peng, Fang; Wang, Qiming; Wang, Kaixue; Wang, Pei; Li, Liang; Li, Yong; Wang, Yonghua [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Yan, Xiaozhi, E-mail: kouzili@scu.edu.cn, E-mail: yanxz@hpstar.ac.cn; Li, Wentao [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203 (China); Bi, Yan [Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China); Leng, Yang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong (China); He, Duanwei [Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China); Institute of Fluid Physics and National Key Laboratory of Shockwave and Detonation Physic, China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-03-23

    Here, we report the sintering of aggregated submicron cubic boron nitride (sm-cBN) at a pressure of 8 GPa. The sintered cBN compacts exhibit hardness values comparable to that of single crystal diamond, fracture toughness about 5-fold that of cBN single crystal, in combination with a high oxidization temperature. Thus, another way has been demonstrated to improve the mechanical properties of cBN besides reducing the grain size to nano scale. In contrast to other ultrahard compacts with similar hardness, the sm-cBN aggregates are better placed for potential industrial application, as their relative low pressure manufacturing perhaps be easier and cheaper.

  1. The influence of residual gas on boron carbide thin films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Boron carbide (B4C) thin films were prepared by magnetron sputtering and residual gas impurities in the films were analyzed by X-ray photoelectron spectroscopy. The impurities, mainly oxygen, decrease with improving vacuum. By using argon ion beam etching of the films, the atomic concentration was measured as a function of etching depth. The binding energy spectra were analyzed using wavelet transform and curve fitting, showing that most of the oxygen impurity is in the form of boron oxides, and that the impurities are physically trapped among columnar structures in the film. In order to improve the base vacuum before coating the film, a range of methods were used, including argon gas filling on the target surface and titanium pre-sputtering. The experimental results show that the latter is an efficient and feasible method. Based on the titanium pre-sputtering technology, the optical performance of W/B4C multilayer was improved so much.

  2. Boron Drug Delivery via Encapsulated Magnetic Nanocomposites: A New Approach for BNCT in Cancer Treatment

    Directory of Open Access Journals (Sweden)

    Yinghuai Zhu

    2010-01-01

    Full Text Available Ortho-carborane cages have been successfully attached to modified magnetic nanoparticles via catalytic azide-alkyne cycloadditions between 1-R-2-butyl-Ortho-C2B10H10(R=Me,3;Ph,4 and propargyl group-enriched magnetic nanoparticles. A loading amount of 9.83 mmol boron atom/g starch-matrixed magnetic nanoparticles has been reached. The resulting nanocomposites have been found to be highly tumor-targeted vehicles under the influence of an external magnetic field (1.14T, yielding a high boron concentration of 51.4 μg/g tumor and ratios of around 10 : 1 tumor to normal tissues.

  3. Modification of silica-based monolithic capillary columns for boronate affinity chromatography

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Dana; Planeta, Josef; Kahle, Vladislav; Roth, Michal

    2011. P2-G-471-WE. ISBN 978-963-89335-0-8. [International Symposium on High - Performance Liquid Phase Separations and Related Techniques /36./. 19.06.2011-23.06.2011, Budapest] R&D Projects: GA AV ČR IAAX00310701; GA MŠk LC06023 Institutional research plan: CEZ:AV0Z40310501 Keywords : silicagel monolithic column * boronate affinity chromatography Subject RIV: CB - Analytical Chemistry, Separation

  4. Water-dispersed thermo-responsive boron nitride nanotubes: synthesis and properties

    Czech Academy of Sciences Publication Activity Database

    Kalay, S.; Stetsyshyn, Y.; Lobaz, Volodymyr; Harhay, K.; Ohar, H.; Ҫulha, M.

    2016-01-01

    Roč. 27, č. 3 (2016), 035703_1-035703_8. ISSN 0957-4484 R&D Projects: GA ČR(CZ) GA13-08336S; GA MPO(CZ) FR-TI4/625 Institutional support: RVO:61389013 Keywords : boron nitride nanotubes * thermo-responsive polymer brushes * poly(N-isopropylacrylamide) Subject RIV: CA - Inorganic Chemistry Impact factor: 3.821, year: 2014

  5. Lab-made Sensors Based on Boron-doped Diamond for Determination of Herbicide Linuron

    Czech Academy of Sciences Publication Activity Database

    Štěpánková, M.; Šelešovská, R.; Janíková, L.; Vojs, M.; Marton, M.; Behúl, M.; Nováková, Kateřina; Chýlková, J.

    Ústí nad Labem: Srsenová Lenka - Best Servis, 2015 - (Navrátil, T.; Fojta, M.; Schwarzová, K.), s. 236-240 ISBN 978-80-905221-3-8. [Moderní elektrochemické metody /35./. Jetřichovice (CZ), 18.05.2015-22.05.2015] Institutional support: RVO:61388955 Keywords : Boron doped diamond electrode * sensors * voltammetry Subject RIV: CG - Electrochemistry

  6. Dual role of boron in improving electrical performance and device stability of low temperature solution processed ZnO thin film transistors

    International Nuclear Information System (INIS)

    In this paper, we have demonstrated the dual role of boron doping in enhancing the device performance parameters as well as the device stability in low temperatures (200 °C) sol-gel processed ZnO thin film transistors (TFTs). Our studies suggest that boron is able to act as a carrier generator and oxygen vacancy suppressor simultaneously. Boron-doped ZnO TFTs with 8 mol. % of boron concentration demonstrated field-effect mobility value of 1.2 cm2 V−1 s−1 and threshold voltage of 6.2 V, respectively. Further, these devices showed lower shift in threshold voltage during the hysteresis and bias stress measurements as compared to undoped ZnO TFTs

  7. Boron Induces Lymphocyte Proliferation and Modulates the Priming Effects of Lipopolysaccharide on Macrophages.

    Directory of Open Access Journals (Sweden)

    Indusmita Routray

    Full Text Available Chemical mediators of inflammation (CMI are important in host defense against infection. The reduced capacity of host to induce the secretion of these mediators following infection is one of the factors in host susceptibility to infection. Boron, which has been suggested for its role in infection, is reported in this study to increase lymphocyte proliferation and the secretion of CMI by the lipopolysaccharide (LPS-stimulated peritoneal macrophages in BALB/c mice. Boron was administered to mice orally as borax at different doses for 10 consecutive days, followed by the stimulation of animals with ovalbumin and isolation of splenocytes for proliferation assay. The lymphocyte subsets were determined by flow cytometry in spleen cell suspension. The mediators of inflammation, TNF-α, IL-6, IL-1β and nitric oxide (NO, were measured in culture supernatant of LPS-primed macrophages isolated from borax treated mice. TNF and ILs were measured by ELISA. NO was determined by Griess test. The expression of inducible nitric oxide synthase (iNOS in macrophages was studied by confocal microscopy. Results showed a significant increase in T and B cell populations, as indicated by an increase in CD4 and CD19, but not CD8, cells. Boron further stimulated the secretion of TNF-α, IL-6, IL-1β, NO and the expression of iNOS by the LPS-primed macrophages. The effect was dose dependent and most significant at a dose level of 4.6 mg/kg b. wt. Taken together, the study concludes that boron at physiological concentration induces lymphocyte proliferation and increases the synthesis and secretion of pro-inflammatory mediators by the LPS-primed macrophages, more specifically the M1 macrophages, possibly acting through Toll-like receptor. The study implicates boron as a regulator of the immune and inflammatory reactions and macrophage polarization, thus playing an important role in augmenting host defense against infection, with possible role in cancer and other diseases.

  8. Boron Induces Lymphocyte Proliferation and Modulates the Priming Effects of Lipopolysaccharide on Macrophages.

    Science.gov (United States)

    Routray, Indusmita; Ali, Shakir

    2016-01-01

    Chemical mediators of inflammation (CMI) are important in host defense against infection. The reduced capacity of host to induce the secretion of these mediators following infection is one of the factors in host susceptibility to infection. Boron, which has been suggested for its role in infection, is reported in this study to increase lymphocyte proliferation and the secretion of CMI by the lipopolysaccharide (LPS)-stimulated peritoneal macrophages in BALB/c mice. Boron was administered to mice orally as borax at different doses for 10 consecutive days, followed by the stimulation of animals with ovalbumin and isolation of splenocytes for proliferation assay. The lymphocyte subsets were determined by flow cytometry in spleen cell suspension. The mediators of inflammation, TNF-α, IL-6, IL-1β and nitric oxide (NO), were measured in culture supernatant of LPS-primed macrophages isolated from borax treated mice. TNF and ILs were measured by ELISA. NO was determined by Griess test. The expression of inducible nitric oxide synthase (iNOS) in macrophages was studied by confocal microscopy. Results showed a significant increase in T and B cell populations, as indicated by an increase in CD4 and CD19, but not CD8, cells. Boron further stimulated the secretion of TNF-α, IL-6, IL-1β, NO and the expression of iNOS by the LPS-primed macrophages. The effect was dose dependent and most significant at a dose level of 4.6 mg/kg b. wt. Taken together, the study concludes that boron at physiological concentration induces lymphocyte proliferation and increases the synthesis and secretion of pro-inflammatory mediators by the LPS-primed macrophages, more specifically the M1 macrophages, possibly acting through Toll-like receptor. The study implicates boron as a regulator of the immune and inflammatory reactions and macrophage polarization, thus playing an important role in augmenting host defense against infection, with possible role in cancer and other diseases. PMID:26934748

  9. Potential of using boric acid as a boron drug for boron neutron capture therapy for osteosarcoma

    International Nuclear Information System (INIS)

    Osteosarcoma is a malignant tumor commonly found in human and animals. The ability of boric acid (BA) to accumulate in osteosarcoma due to the mechanism of the bone formation of cancer cells would make boron neutron capture therapy (BNCT) an alternative therapy for osteosarcoma. This study evaluated the feasibility of using BA as the boron drug for BNCT of bone cancer. The cytotoxicity of BA to L929 cells exceeded that of UMR-106 cells. With 25 μg 10B/mL medium of BA treatment, the boron concentration in UMR-106 cells was higher than that in L929 cells. The biodistribution and pharmacokinetics of BA in Sprague–Dawley (SD) rats were studied by administrating 25 mg 10B/kg body weight to SD rats. Blood boron level decreased rapidly within one hour after BA injection. Boron concentration in the long bone was 4–6 time higher than that of blood. Results of this study suggest that BA may be a potential drug for BNCT for osteosarcoma.

  10. Recent results at the SIRa test bench Diffusion properties of carbon graphite and B sub 4 C targets

    CERN Document Server

    Landre-Pellemoine, F; Bajeat, O; Barue, C; Bennett, R; Clapier, F; Ducourtieux, M; Gaubert, G; Gibouin, S; Huguet, Y; Jardin, P; Kandri-Rody, S; Lau, C; Lecesne, N; Leroy, R; Lewitowicz, M; Lichtenthäler, R; Marry, C; Maunoury, L; Obert, J; Orr, N A; Pacquet, J Y; Saint-Laurent, M G; Stodel, C; Rataud, J P; Villari, A C C

    2002-01-01

    The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for sup 6 He (T sub 1 sub / sub 2 =806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B sub 4 C (boron carbide) have also been studied. Yields of 1.4x10 sup 8 pps and 5.0x10 sup 5 pps for sup 6 He and sup 8 He has been obtained.

  11. Diffusion Boronizing of H11 Hot Work Tool Steel

    Science.gov (United States)

    Jurči, Peter; Hudáková, Mária

    2011-10-01

    The H11 hot work tool steel was boronized at various processing parameters, austenitized, quenched, and tempered to a core hardness of 47-48 HRC. Microstructure, phase constitution, and microhardness of boronized layers were investigated. Effect of boronized region on the bulk properties was determined by the Charpy impact test. Structure of boronized regions is formed by the compound layers and diffusion inter-layer. The compound layers consisted of only (Fe,Cr)2B phase, but in the case of longer processing time, they contained also of the (Fe,Cr)B-phase. The inter-layer contained enhanced portion of carbides, formed due to carbon diffusion from the boride compounds toward the substrate. Microhardness of boronized layers exceeded considerably 2000 HV 0.1. However, boronizing led to a substantial lowering of the Charpy impact toughness of the material.

  12. Boron Rich Solids Sensors, Ultra High Temperature Ceramics, Thermoelectrics, Armor

    CERN Document Server

    Orlovskaya, Nina

    2011-01-01

    The objective of this book is to discuss the current status of research and development of boron-rich solids as sensors, ultra-high temperature ceramics, thermoelectrics, and armor. Novel biological and chemical sensors made of stiff and light-weight boron-rich solids are very exciting and efficient for applications in medical diagnoses, environmental surveillance and the detection of pathogen and biological/chemical terrorism agents. Ultra-high temperature ceramic composites exhibit excellent oxidation and corrosion resistance for hypersonic vehicle applications. Boron-rich solids are also promising candidates for high-temperature thermoelectric conversion. Armor is another very important application of boron-rich solids, since most of them exhibit very high hardness, which makes them perfect candidates with high resistance to ballistic impact. The following topical areas are presented: •boron-rich solids: science and technology; •synthesis and sintering strategies of boron rich solids; •microcantileve...

  13. Van Hove singularities of some icosahedral boron-rich solids by differential reflectivity spectra

    Science.gov (United States)

    Werheit, Helmut

    2015-09-01

    Differential reflectivity spectra of some icosahedral boron rich solids, β-rhombohedral boron, boron carbide and YB66-type crystals, were measured. The derivatives yield the van Hove singularities, which are compared with results obtained by other experimental methods.

  14. The effect of in ovo boron supplementation on bone mineralization of the vitamin D-deficient chicken embryo.

    Science.gov (United States)

    King, N; Odom, T W; Sampson, H W; Yersin, A G

    1991-12-01

    It has been hypothesized that boron (B) is an essential element for animals, but its action will vary greatly depending on the nutriture of the organism. One of the nutrients implicated as having an interaction with boron is cholecalciferol (Vit D3). This study was carried out to determine if such an interaction exists. The study was conducted utilizing vitamin D-deficient chicken embryos that were injected through the shell at 8 d of embryogenesis with carrier (NaCl and/or acetone), B (0.5 mg), B + Vit D3 (0.5 mg and 0.3 microgram, respectively), or Vit D3 (0.3 or 1.5 micrograms). The in ovo concomitant administration of boron and vitamin D enhanced (p less than 0.05) the hatchability of the vitamin D-deficient embryos. Furthermore, boron and/or vitamin D3 increased (p less than 0.05) the percent of bone ash and decreased (p less than 0.05) the exaggerated height of the proliferative zone of the epiphyseal growth plate normally observed in vitamin D deficiency, suggesting a more rapid bone formation. The results provide further evidence supporting the hypothesis that boron plays a role in bone mineralization through an interaction with vitamin D. PMID:1723613

  15. Valence band offset and Schottky barrier at amorphous boron and boron carbide interfaces with silicon and copper

    International Nuclear Information System (INIS)

    In order to understand the fundamental charge transport in a-B:H and a-BX:H (X = C, N, P) compound heterostructure devices, X-ray photoelectron spectroscopy has been utilized to determine the valence band offset and Schottky barrier present at amorphous boron compound interfaces formed with (1 0 0) Si and polished poly-crystalline Cu substrates. For interfaces formed by plasma enhanced chemical vapor deposition of a-B4–5C:H on (1 0 0) Si, relatively small valence band offsets of 0.2 ± 0.2 eV were determined. For a-B:H/Cu interfaces, a more significant Schottky barrier of 0.8 ± 0.16 eV was measured. These results are in contrast to those observed for a-BN:H and BP where more significant band discontinuities (>1–2 eV) were observed for interfaces with Si and Cu.

  16. Valence band offset and Schottky barrier at amorphous boron and boron carbide interfaces with silicon and copper

    Energy Technology Data Exchange (ETDEWEB)

    King, Sean W., E-mail: sean.king@intel.com [Logic Technology Development, Intel Corporation, 5200 NE Elam Young Parkway, Hillsboro, OR 97124 (United States); French, Marc; Xu, Guanghai [Logic Technology Development, Intel Corporation, 5200 NE Elam Young Parkway, Hillsboro, OR 97124 (United States); French, Benjamin [Ocotillo Materials Laboratory, Intel Corporation, 4500 S. Dobson Road, Chandler, AZ 85248 (United States); Jaehnig, Milt; Bielefeld, Jeff; Brockman, Justin; Kuhn, Markus [Logic Technology Development, Intel Corporation, 5200 NE Elam Young Parkway, Hillsboro, OR 97124 (United States)

    2013-11-15

    In order to understand the fundamental charge transport in a-B:H and a-BX:H (X = C, N, P) compound heterostructure devices, X-ray photoelectron spectroscopy has been utilized to determine the valence band offset and Schottky barrier present at amorphous boron compound interfaces formed with (1 0 0) Si and polished poly-crystalline Cu substrates. For interfaces formed by plasma enhanced chemical vapor deposition of a-B{sub 4–5}C:H on (1 0 0) Si, relatively small valence band offsets of 0.2 ± 0.2 eV were determined. For a-B:H/Cu interfaces, a more significant Schottky barrier of 0.8 ± 0.16 eV was measured. These results are in contrast to those observed for a-BN:H and BP where more significant band discontinuities (>1–2 eV) were observed for interfaces with Si and Cu.

  17. High quality boron carbon nitride/ZnO-nanorods p-n heterojunctions based on magnetron sputtered boron carbon nitride films

    International Nuclear Information System (INIS)

    Boron carbon nitride (BCN) films were synthesized on Si (100) and fused silica substrates by radio-frequency magnetron sputtering from a B4C target in an Ar/N2 gas mixture. The BCN films were amorphous, and they exhibited an optical band gap of ∼1.0 eV and p-type conductivity. The BCN films were over-coated with ZnO nanorod arrays using hydrothermal synthesis to form BCN/ZnO-nanorods p-n heterojunctions, exhibiting a rectification ratio of 1500 at bias voltages of ±5 V

  18. Multidimensional boron transport modeling in subchannel approach

    International Nuclear Information System (INIS)

    The main objective of this study is to implement a solute tracking model into the subchannel code CTF for simulations of boric acid transients. Previously, three different boron tracking models have been implemented into CTF and based on the applied analytical and nodal sensitivity studies the Modified Godunov Scheme approach with a physical diffusion term has been selected as the most accurate and best estimate solution. This paper will present the implementation of a multidimensional boron transport modeling with Modified Godunov Scheme within a thermal-hydraulic code based on a subchannel approach. Based on the cross flow mechanism in a multiple-subchannel rod bundle geometry, heat transfer and lateral pressure drop effects will be discussed in deboration and boration case studies. (author)

  19. Synthesis and characterization of boron nitrides nanotubes

    International Nuclear Information System (INIS)

    This paper presents a new synthesis for the production of boron nitride nanotubes (BNNT) from boron powder, ammonium nitrate and hematite tube furnace CVD method. The samples were subjected to some characterization techniques as infrared spectroscopy, thermal analysis, X-ray diffraction and scanning electron microscopy and transmission. By analyzing the results can explain the chemical reactions involved in the process and confirm the formation of BNNT with several layers and about 30 nanometers in diameter. Due to excellent mechanical properties and its chemical and thermal stability this material is promising for various applications. However, BNNT has received much less attention than carbon nanotubes, it is because of great difficulty to synthesize appreciable quantities from the techniques currently known, and this is one of the main reasons this work.(author)

  20. Microadditions of boron and vanadium in ADI

    Directory of Open Access Journals (Sweden)

    Rzychoń T.

    2007-01-01

    Full Text Available In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI. Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.