Pre-operative use of anti-TNF-α agents and the risk of post-operative complications in patients with ulcerative colitis - a nationwide cohort study

DEFF Research Database (Denmark)

Nørgård, B M; Nielsen, J; Qvist, N

2012-01-01

It is still controversial whether pre-operative anti-tumour necrosis factor-alpha (anti-TNF-α) agents increase post-operative complications in patients with ulcerative colitis (UC).......It is still controversial whether pre-operative anti-tumour necrosis factor-alpha (anti-TNF-α) agents increase post-operative complications in patients with ulcerative colitis (UC)....

Synthesis of Various Polyaniline / Clay Nanocomposites Derived from Aniline and Substituted Aniline Derivatives by Mechanochemical Intercalation Method

Directory of Open Access Journals (Sweden)

N. Kalaivasan

2010-01-01

Full Text Available Polyaniline clay nanocomposite can be prepared by mechano-chemical method in which intercalation of anilinium ion into the clay lattices accomplished by mechanical grinding of sodium montmorillonite (Na+MMT in presence of anilinium hydrochloride at room temperature using mortar & pestle for about 30 min and subsequent grinding with oxidizing agent, ammonium peroxysulfate. The appearance of green colour indicates the formation of polyaniline/clay nanocomposite (PANI/Clay. Similarly aniline derivatives like o-toludine and o-anisidine in the form of HCl salt can form intercalation into the clay lattices. The intercalated aniline derivatives were ground mechanically in presence of oxidizing agent ammonium peroxysulfate lead to formation of substituted polyaniline/ clay nanocomposites. The characteristics of various polyaniline-clay nanocomposites were investigated using UV-Visible, FT-IR, cyclic voltammetry studies.

Polysaccharides from Sargassum thunbergii: Monthly variations and anti-complement and anti-tumour activities.

Science.gov (United States)

Jin, Weihua; Liu, Ge; Zhong, Weihong; Sun, Chaomin; Zhang, Quanbin

2017-12-01

Monthly variations of polysaccharides from Sargassum thunbergii and their anti-complement and anti-tumour activities were investigated. It was observed that an increase in fucose and total sugar contents occurred during the growth period (from early April to mid-June), accompanied by a decrease in molar ratios of other monosaccharides to fucose. The highest yields were obtained from early July to early September, which was in accordance with the significant increase in molar ratio of glucose to fucose and decrease in molar ratio of other monosaccharides to fucose. And the above results suggested that S. Thunbergii synthesized large amount of laminaran, the storage substance of brown algae, during the senescence period. However, sulfate contents were relatively stable in the life cycle of S. thunbergii. These results suggested that S. thunbergii synthesized complex sulfated heteropolysacchairdes during inactive period, while during other periods, it synthesized more sulfated galactofucan. All polysaccharides showed anti-complement activity, suggesting that the harvesting time did not influence the anti-complement activities. In the anti-tumour assay in vitro, the polysaccharides taken during the senescence period had much lower anti-tumour activity, suggesting that fucoidan, but not laminaran, determined the anti-tumour activities. Therefore, polysaccharides from S. thunbergii might have great potential in anti-complement and anti-tumour application. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of propylene-graft-maleic anhydride and the co-intercalant cis-13- docosenamide on the structure and mechanical properties of PP/organoclay clay systems

International Nuclear Information System (INIS)

Silva Neto, J.E. da; Almeida, T.G.; Leite, R.C.N.; Carvalho, L.H.; Alves, T.S.

2014-01-01

In this work, PP/organoclay hybrids were prepared by melt intercalation and the effect of adding different amounts of a compatibilizer (PP-G-MA) and a co-intercalating agent (cis-13-docosenamide) to maximize the compatibility between filler and the polymeric matrix were investigated. The systems were processed under a single condition on a co-rotating twin screw extruder. The morphology and mechanical properties of the nanocomposites were investigated. The hybrids were characterized by x-ray diffraction, tensile (ASTM D638) and impact properties (ASTM D256). The results indicated an approximately 45% increase of the basal interplanar distance d_(_0_0_1_) of the clay on hybrid systems, containing both compatibilizing and co-intercalating agents, forming intercalated structures. The tensile strength of the systems was not affected significantly by compatibilizer and/or co-intercalant addition, however, increases of up to 30% in elastic modulus and 48% in impact strength were obtained. (author)

Intercalation chemistry of zirconium 4-sulfophenylphosphonate

International Nuclear Information System (INIS)

Svoboda, Jan; Zima, Vítězslav; Melánová, Klára; Beneš, Ludvík; Trchová, Miroslava

2013-01-01

Zirconium 4-sulfophenylphosphonate is a layered material which can be employed as a host for the intercalation reactions with basic molecules. A wide range of organic compounds were chosen to represent intercalation ability of zirconium 4-sulfophenylphosphonate. These were a series of alkylamines from methylamine to dodecylamine, 1,4-phenylenediamine, p-toluidine, 1,8-diaminonaphthalene, 1-aminopyrene, imidazole, pyridine, 4,4′-bipyridine, poly(ethylene imine), and a series of amino acids from glycine to 6-aminocaproic acid. The prepared compounds were characterized by powder X-ray diffraction, thermogravimetry analysis and IR spectroscopy and probable arrangement of the guest molecules in the interlayer space of the host is proposed based on the interlayer distance of the prepared intercalates and amount of the intercalated guest molecules. - Graphical abstract: Nitrogen-containing organic compounds can be intercalated into the interlayer space of zirconium 4-sulfophenylphosphonate. - Highlights: • Zirconium 4-sulfophenylphosphonate was examined as a host material in intercalation chemistry. • A wide range of nitrogen-containing organic compounds were intercalated. • Possible arrangement of the intercalated species is described

High pressure measurement of the uniaxial stress of host layers on intercalants and staging transformation of intercalation compounds

CERN Document Server

Park, T R; Kim, H; Min, P

2002-01-01

A layered double-hydroxide intercalation compound was synthesized to measure the uniaxial stress the host layers exert on the intercalants. To measure the uniaxial stress, we employed the photoluminescence (PL) from the intercalated species, the Sm ion complex, as it is sensitive to the deformation of the intercalants. Of the many PL peaks the Sm ion complex produces, the one that is independent of the counter-cation environment was chosen for the measurement since the Sm ion complexes are placed under a different electrostatic environment after intercalation. The peak position of the PL was redshifted linearly with increasing hydrostatic pressure on the intercalated sample. Using this pressure-induced redshifting rate and the PL difference at ambient pressure between the pre-intercalation and the intercalated ions, we found that, in the absence of external pressure, the uniaxial stress exerted on the samarium ion complexes by the host layers was about 13.9 GPa at room temperature. Time-resolved PL data also ...

Direct intercalation of cisplatin into zirconium phosphate nanoplatelets for potential cancer nanotherapy

Science.gov (United States)

Díaz, Agustín; González, Millie L.; Pérez, Riviam J.; David, Amanda; Mukherjee, Atashi; Báez, Adriana; Clearfield, Abraham

2014-01-01

We report the use of zirconium phosphate nanoplatelets (ZrP) for the encapsulation of the anticancer drug cisplatin and its delivery to tumor cells. Cisplatin was intercalated into ZrP by direct-ion exchange and was tested in-vitro for cytotoxicity in the human breast cancer (MCF-7) cell line. The structural characterization of the intercalated cisplatin in ZrP suggests that during the intercalation process, the chloride ligands of the cisplatin complex were substituted by phosphate groups within the layers. Consequently, a new phosphate phase with the platinum complex directly bound to ZrP (cisPt@ZrP) is produced with an interlayer distance of 9.3 Å. The in-vitro release profile of the intercalated drug by pH stimulus shows that at low pH under lysosomal conditions the platinum complex is released with simultaneous hydrolysis of the zirconium phosphate material, while at higher pH the complex is not released. Experiments with the MCF-7 cell line show that cisPt@ZrP reduced the cell viability up to 40%. The cisPt@ZrP intercalation product is envisioned as a future nanotherapy agent for cancer. Taking advantage of the shape and sizes of the ZrP particles and controlled release of the drug at low pH, it is intended to exploit the enhanced permeability and retention effect of tumors, as well as their intrinsic acidity, for the destruction of malignant cells. PMID:24072038

Presence of Cx43 in extracellular vesicles reduces the cardiotoxicity of the anti-tumour therapeutic approach with doxorubicin

Directory of Open Access Journals (Sweden)

Tania Martins-Marques

2016-09-01

Full Text Available Extracellular vesicles (EVs are major conveyors of biological information, mediating local and systemic cell-to-cell communication under physiological and pathological conditions. These endogenous vesicles have been recognized as prominent drug delivery vehicles of several therapeutic cargoes, including doxorubicin (dox, presenting major advantages over the classical approaches. Although dox is one of the most effective anti-tumour agents in the clinical practice, its use is very often hindered by its consequent dramatic cardiotoxicity. Despite significant advances witnessed in the past few years, more comprehensive studies, supporting the therapeutic efficacy of EVs, with decreased side effects, are still scarce. The main objective of this study was to evaluate the role of the gap junction protein connexin43 (Cx43 in mediating the release of EV content into tumour cells. Moreover, we investigated whether Cx43 improves the efficiency of dox-based anti-tumour treatment, with a concomitant decrease of cardiotoxicity. In the present report, we demonstrate that the presence of Cx43 in EVs increases the release of luciferin from EVs into tumour cells in vitro and in vivo. In addition, using cell-based approaches and a subcutaneous mouse tumour model, we show that the anti-tumour effect of dox incorporated into EVs is similar to the administration of the free drug, regardless the presence of Cx43. Strikingly, we demonstrate that the presence of Cx43 in dox-loaded EVs reduces the cardiotoxicity of the drug. Altogether, these results bring new insights into the concrete potential of EVs as therapeutic vehicles and open new avenues toward the development of strategies that help to reduce unwanted side effects.

Carbon fibers and composites modified by intercalation

International Nuclear Information System (INIS)

Macherzynska, B.; Blazewicz, S.

2002-01-01

The aim of this paper was to describe ability to intercalation of laboratory prepared carbon composites and their constituents. In work the following materials were tested; pinch-based fibres of P-120 and K-1100 manufacturer's designations, carbon matrix and resulting composites. To prepare a matrix of composites, phenol-formaldehyde resin (Z) and pinch-based precursor (PAK) were used. After initial carbonization, the carbon matrix was heated to 2150 o C i to improve ability to the future intercalation. Three kinds of composites (P/Z, K/Z and K/PAK), with two directional reinforcement (2D), were prepared. All carbon samples were intercalated with copper chloride(II). To study the structure of all materials, before and after intercalation, X-ray diffraction method was used. It enabled to measure microstructure parameters (L c and L a ), interplanar distance (d 002 ) thickness of an intercalation layer (d i ). Before intercalation, graphite fibers are characterized by well developed graphite structure of three-dimensional order, different than carbon turbostratic structures. Graphite fibres show a tendency to intercalation, however this process proceeds harder than in a synthetic graphite, which is testified by diffraction spectra with visible complex stages of intercalation. Comparison of two kinds of graphite fibres show s that their structure significantly affects intercalation process. In the case of composite matrix, a better structure ordering was observed for carbon obtained from PAK than for carbon originating from Z precursor. During production of composites, after the heat treatment (2150 o C), carbon obtained from pyrolysis of Z precursor crystallises on the fibre surface, building a well-developed structure of matrix. The same process occurs during carbonization of pinch-based precursor in presence of graphite fibres. In both cases the composites contain well crystallized graphite phases. The study of carbon composite intercalation shows that the process

The intercalation chemistry of layered iron chalcogenide superconductors

Energy Technology Data Exchange (ETDEWEB)

Vivanco, Hector K.; Rodriguez, Efrain E., E-mail: efrain@umd.edu

2016-10-15

The iron chalcogenides FeSe and FeS are superconductors composed of two-dimensional sheets held together by van der Waals interactions, which makes them prime candidates for the intercalation of various guest species. We review the intercalation chemistry of FeSe and FeS superconductors and discuss their synthesis, structure, and physical properties. Before we review the latest work in this area, we provide a brief background on the intercalation chemistry of other inorganic materials that exhibit enhanced superconducting properties upon intercalation, which include the transition metal dichalcogenides, fullerenes, and layered cobalt oxides. From past studies of these intercalated superconductors, we discuss the role of the intercalates in terms of charge doping, structural distortions, and Fermi surface reconstruction. We also briefly review the physical and chemical properties of the host materials—mackinawite-type FeS and β-FeSe. The three types of intercalates for the iron chalcogenides can be placed in three categories: 1.) alkali and alkaline earth cations intercalated through the liquid ammonia technique; 2.) cations intercalated with organic amines such as ethylenediamine; and 3.) layered hydroxides intercalated during hydrothermal conditions. A recurring theme in these studies is the role of the intercalated guest in electron doping the chalcogenide host and in enhancing the two-dimensionality of the electronic structure by spacing the FeSe layers apart. We end this review discussing possible new avenues in the intercalation chemistry of transition metal monochalcogenides, and the promise of these materials as a unique set of new inorganic two-dimensional systems.

Mechanisms of nanoclay-enhanced plastic foaming processes: effects of nanoclay intercalation and exfoliation

Energy Technology Data Exchange (ETDEWEB)

Wong, Anson; Wijnands, Stephan F. L.; Kuboki, Takashi; Park, Chul B., E-mail: park@mie.utoronto.ca [University of Toronto, Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering (Canada)

2013-08-15

The foaming behaviors of high-density polypropylene-nanoclay composites with intercalated and exfoliated nanoclay particles blown with carbon dioxide were examined via in situ observation of the foaming processes in a high-temperature/high-pressure view-cell. The intercalated nanoclay particles were 300-600 nm in length and 50-200 nm in thickness, while the exfoliated nanoclay particles were 100-200 nm in length and 1 nm in thickness. Contrary to common belief, it was discovered that intercalated nanoclay yielded higher cell density than exfoliated nanoclay despite its lower particle density. This was attributed to the higher tensile stresses generated around the larger and stiffer intercalated nanoclay particles, which led to increase in supersaturation level for cell nucleation. Also, the coupling agent used to exfoliate nanoclay would increase the affinity between polymer and surface of nanoclay particles. Consequently, the critical work needed for cell nucleation would be increased; pre-existing microvoids, which could act as seeds for cell nucleation, were also less likely to exist. Meanwhile, exfoliated nanoclay had better cell stabilization ability to prevent cell coalescence and cell coarsening. This investigation clarifies the roles of nanoclay in plastic foaming processes and provides guidance for the advancement of polymer nanocomposite foaming technology.

Charge carrier density in Li-intercalated graphene

KAUST Repository

Kaloni, Thaneshwor P.

2012-05-01

The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young\\'s modulus suggests that Li-intercalation increases the intrinsic stiffness. For decreasing Li-C interaction, the Dirac point shifts to the Fermi level and the associated band splitting vanishes. For Li-intercalated bilayer graphene on SiC(0 0 0 1) the splitting at the Dirac point is tiny. It is also very small at the two Dirac points of Li-intercalated trilayer graphene on SiC(0 0 0 1). For all the systems under study, a large enhancement of the charge carrier density is achieved by Li intercalation. © 2012 Elsevier B.V. All rights reserved.

Intercalation of lanthanide trichlorides in graphite

International Nuclear Information System (INIS)

Stumpp, E.; Nietfeld, G.

1979-01-01

The reactions of the whole series of lanthanide trichlorides with graphite have been investigated. Intercalation compounds have been prepared with the chlorides of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y whereas LaCl 3 , CeCl 3 , PrCl 3 and NdCl 3 do not intercalate. The compounds were characterized by chemical and X-ray analysis. The amount of c-axis increase is consistent with the assumption that the chlorides are intercalated in form of a chloride layer sandwich resmbling the sheets in YCl 3 . The chlorides which do not intercalate crystallize in the UCl 3 structure having 3 D arrangements of ions. Obviously, these chlorides cannot form sheets between the carbon layers. The ability of AlCl 3 to volatilize lanthanide chlorides through complex formation in the gas phase can be used to increase the intercalation rate strikingly. (author)

One-step exfoliation and surface modification of lamellar hydroxyapatite by intercalation of glucosamine

Energy Technology Data Exchange (ETDEWEB)

Luo, Honglin [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Li, Wei; Ji, Dehui [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zuo, Guifu [Hebei Provincial Key Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, Hebei United University, Tangshan, 063009 (China); Xiong, Guangyao, E-mail: xiongguangyao@163.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Zhu, Yong [School of Chemical Engineering, Tianjin University, Tianjin, 300072 (China); Li, Lili; Han, Ming [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); Wu, Caoqun [School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China); Wan, Yizao, E-mail: yzwantju@126.com [Research Institute for Biomaterials and Transportation, East China Jiaotong University, Nanchang, 330013 (China); School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 (China)

2016-04-15

Effective exfoliation is crucial to the application of layered materials in many fields. Herein, we report a novel effective, scalable, and ecofriendly method for the exfoliation of lamellar HAp by glucosamine intercalation such that individual HAp nanoplates can be obtained. The as-exfoliated HAp nanoplates were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric (TG) analysis. It is found that the glucosamine intercalation not only results in complete exfoliation of lamellar HAp but also introduces the glucosamine molecules onto the surface of individual HAp nanoplates, thus obtaining separated glucosamine-grafted HAp nanoplates (Glu-HAps). Results from MTT assay demonstrate that glucosamine grafting on HAp nanoplates greatly improves the cell growth and proliferation as compared to nongrafted HAp counterparts. - Highlights: • Glucosamine was used as intercalation agent to exfoliate lamellar hydroxyapatite. • Glucosamine was grafted onto the as-exfoliated nanoplate-like hydroxyapatite. • Exfoliation and surface grafting were accomplished in one step. • Glucosamine-grafted HAp showed improved biocompatibility over nongrafted one.

Superconductivity of TiNCl intercalated with diamines

International Nuclear Information System (INIS)

Yamanaka, Shoji; Umemoto, Keita

2010-01-01

Intercalation compounds of TiNCl with ethylenediamine (EDA) and hexamethylenediamine (HDA) were prepared. The basal spacing of TiNCl increased by 3.3-3.9 A upon intercalation, implying that the molecules are lying with the alkyl chains parallel to the TiNCl layers in both compounds. The intercalated compounds showed superconductivity with transition temperatures (T c s) of 10.5 and 15.5 K for EDA and HDA, respectively, which are higher than 8.6 K of pyridine (Py) intercalated compound, Py 0.25 TiNCl.

Intercalation of organic molecules into SnS2 single crystals

International Nuclear Information System (INIS)

Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H.; Kloc, C.

2013-01-01

SnS 2 is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS 2e n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS 2 after intercalation revealed defects and stacking mismatches among the SnS 2 layers caused by the intercalation. UV–Vis absorption studies showed a red shift in the band edge of the SnS 2 material after intercalation. The band edge was 2.2 eV for pristine SnS 2 ; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS 2 single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS 2 after intercalation. Highlights: ► Organic molecules intercalated inhomogenously between covalently bonded SnS 2 layers. ► Ethylenediamine (en) intercalate directly into SnS 2 . ► Phenylenediamine (PPD) and naphthalenediamine (NDA) can be intercalated into SnS 2 secondary. ► In a secondary intercalation the bonds between layers are weakened by direct

Nanoemulsion formulation of fisetin improves bioavailability and antitumour activity in mice.

Science.gov (United States)

Ragelle, Héloïse; Crauste-Manciet, Sylvie; Seguin, Johanne; Brossard, Denis; Scherman, Daniel; Arnaud, Philippe; Chabot, Guy G

2012-05-10

The natural flavonoid fisetin (3,3',4',7-tetrahydroxyflavone) has shown antitumour activity but its administration is complicated by its low water solubility. Our aim was to incorporate fisetin into a nanoemulsion to improve its pharmacokinetics and therapeutic efficacy. Solubility and emulsification tests allowed to develop an optimal nanoemulsion composed of Miglyol 812N/Labrasol/Tween 80/Lipoid E80/water (10%/10%/2.5%/1.2%/76.3%). The nanoemulsion had an oil droplet diameter of 153 ± 2 nm, a negative zeta potential (-28.4 ± 0.6 mV) and a polydispersity index of 0.129. The nanoemulsion was stable at 4 °C for 30 days, but phase separation occurred at 20 °C. Pharmacokinetic studies in mice revealed that the fisetin nanoemulsion injected intravenously (13 mg/kg) showed no significant difference in systemic exposure compared to free fisetin. However, when the fisetin nanoemulsion was administered intraperitoneally, a 24-fold increase in fisetin relative bioavailability was noted, compared to free fisetin. Additionally, the antitumour activity of the fisetin nanoemulsion in Lewis lung carcinoma bearing mice occurred at lower doses (36.6 mg/kg) compared to free fisetin (223 mg/kg). In conclusion, we have developed a stable nanoemulsion of fisetin and have shown that it could improve its relative bioavailability and antitumour activity. Copyright © 2012 Elsevier B.V. All rights reserved.

Superconductivity of TiNCl intercalated with diamines

Energy Technology Data Exchange (ETDEWEB)

Yamanaka, Shoji, E-mail: syamana@hiroshima-u.ac.j [Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Umemoto, Keita [Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)

2010-12-15

Intercalation compounds of TiNCl with ethylenediamine (EDA) and hexamethylenediamine (HDA) were prepared. The basal spacing of TiNCl increased by 3.3-3.9 A upon intercalation, implying that the molecules are lying with the alkyl chains parallel to the TiNCl layers in both compounds. The intercalated compounds showed superconductivity with transition temperatures (T{sub c}s) of 10.5 and 15.5 K for EDA and HDA, respectively, which are higher than 8.6 K of pyridine (Py) intercalated compound, Py{sub 0.25}TiNCl.

Fabrication of Li-intercalated bilayer graphene

Directory of Open Access Journals (Sweden)

K. Sugawara

2011-06-01

Full Text Available We have succeeded in fabricating Li-intercalated bilayer graphene on silicon carbide. The low-energy electron diffraction from Li-deposited bilayer graphene shows a sharp 3×3R30° pattern in contrast to Li-deposited monolayer graphene. This indicates that Li atoms are intercalated between two adjacent graphene layers and take the same well-ordered superstructure as in bulk C6Li. The angle-resolved photoemission spectroscopy has revealed that Li atoms are fully ionized and the π bands of graphene are systematically folded by the superstructure of intercalated Li atoms, producing a snowflake-like Fermi surface centered at the Γ point. The present result suggests a high potential of Li-intercalated bilayer graphene for application to a nano-scale Li-ion battery.

Superconductivity in graphite intercalation compounds

International Nuclear Information System (INIS)

Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P.M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

2015-01-01

Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC 6 and YbC 6 in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition

Superconductivity in graphite intercalation compounds

Energy Technology Data Exchange (ETDEWEB)

Smith, Robert P. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Weller, Thomas E.; Howard, Christopher A. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Dean, Mark P.M. [Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Rahnejat, Kaveh C. [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom); Saxena, Siddharth S. [Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom); Ellerby, Mark, E-mail: mark.ellerby@ucl.ac.uk [Department of Physics & Astronomy, University College of London, Gower Street, London WCIE 6BT (United Kingdom)

2015-07-15

Highlights: • Historical background of graphite intercalates. • Superconductivity in graphite intercalates and its place in the field of superconductivity. • Recent developments. • Relevant modeling of superconductivity in graphite intercalates. • Interpretations that pertain and questions that remain. - Abstract: The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC{sub 6} and YbC{sub 6} in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

Voreloxin is an anticancer quinolone derivative that intercalates DNA and poisons topoisomerase II.

Directory of Open Access Journals (Sweden)

Rachael E Hawtin

2010-04-01

Full Text Available Topoisomerase II is critical for DNA replication, transcription and chromosome segregation and is a well validated target of anti-neoplastic drugs including the anthracyclines and epipodophyllotoxins. However, these drugs are limited by common tumor resistance mechanisms and side-effect profiles. Novel topoisomerase II-targeting agents may benefit patients who prove resistant to currently available topoisomerase II-targeting drugs or encounter unacceptable toxicities. Voreloxin is an anticancer quinolone derivative, a chemical scaffold not used previously for cancer treatment. Voreloxin is completing Phase 2 clinical trials in acute myeloid leukemia and platinum-resistant ovarian cancer. This study defined voreloxin's anticancer mechanism of action as a critical component of rational clinical development informed by translational research.Biochemical and cell-based studies established that voreloxin intercalates DNA and poisons topoisomerase II, causing DNA double-strand breaks, G2 arrest, and apoptosis. Voreloxin is differentiated both structurally and mechanistically from other topoisomerase II poisons currently in use as chemotherapeutics. In cell-based studies, voreloxin poisoned topoisomerase II and caused dose-dependent, site-selective DNA fragmentation analogous to that of quinolone antibacterials in prokaryotes; in contrast etoposide, the nonintercalating epipodophyllotoxin topoisomerase II poison, caused extensive DNA fragmentation. Etoposide's activity was highly dependent on topoisomerase II while voreloxin and the intercalating anthracycline topoisomerase II poison, doxorubicin, had comparable dependence on this enzyme for inducing G2 arrest. Mechanistic interrogation with voreloxin analogs revealed that intercalation is required for voreloxin's activity; a nonintercalating analog did not inhibit proliferation or induce G2 arrest, while an analog with enhanced intercalation was 9.5-fold more potent.As a first-in-class anticancer

Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

Energy Technology Data Exchange (ETDEWEB)

Gao, Xiaorui, E-mail: gxr_1320@sina.com [College of Science, Hebei University of Engineering, Handan 056038 (China); School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Lei, Lixu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); O' Hare, Dermot [Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Xie, Juan [College of Science, Hebei University of Engineering, Handan 056038 (China); Gao, Pengran [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chang, Tao [College of Science, Hebei University of Engineering, Handan 056038 (China)

2013-07-15

Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg–Al and Mg–Fe layered double hydroxides (LDHs) have been synthesized by the calcination–rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV–vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO{sub 3}{sup 2−} solutions imply that Mg{sub 3}Al–VC LDH is a better controlled release system than Mg{sub 3}Fe–VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO{sub 3}{sup 2−} solution. - Graphical abstract: Vitamin C anions have been intercalated in the interlayer space of layered double hydroxide and released in CO{sub 3}{sup 2−} solution and deionised water. - Highlights: • Vitamin C intercalated Mg–Al and Mg–Fe layered double hydroxides were prepared. • Release property of vitamin C in aqueous CO{sub 3}{sup 2−} solution is better. • Avrami-Erofe’ev and first-order models provide better fit for release results. • Diffusion-controlled and ion exchange processes occur in deionised water. • An ion exchange process occurs in CO{sub 3}{sup 2−} solution.

Magnetic resonance studies of intercalation compounds

International Nuclear Information System (INIS)

Miller, G.R.

1990-01-01

During the last three or four years, nearly tow hundred papers have been published that used NMR or ESR spectroscopy to study compounds formed by the intercalation of molecules or ions into the van der Waals gap of a layered hast compound. The host lattices have ranged from the simple, such as graphite, to the complex, such as clay. In many cases, magnetic resonance techniques now enable one to obtain quite detailed information on even fairly complex intercalated species, on the nature of the changes in the host lattice accompanying intercalation, and on the nature of the interactions between the intercalant species and the host lattice. Magnetic resonance is used in conunction with many other techniques to obtain a fuller picture of these interesting systems, but this review will limit its focus to the use of NMR and ESR techniques. (author). 51 refs

Large magnetoresistance in intercalated Cu oxides

OpenAIRE

Grigoryan, L.; Furusawa, M.; Hori, H.; Tokumoto, M.

1997-01-01

Magnetism and electrical resistance as a function of magnetic field, temperature, and chemical composition are studied in Cu oxides intercalated with metal phthalocyanines MPc, where M is Fe or Ni, and Pc is C_H_N_. An unusually large positive magnetoresistance (MR) of ～ 1200% is observed in FePc-intercalated Bi_Sr_Ca_Cu_O_ samples with two Cu-O layers in the unit cell (n=2). The magnitude of the MR decreased to 40% and ～ 0% in the FePc-intercalated n=3 and n=4 samples, respectively, and to ～...

Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review.

Science.gov (United States)

Cör, Darija; Knez, Željko; Knez Hrnčič, Maša

2018-03-13

Ganoderma lucidum (Reishi) is a popular medicinal mushroom and has been used in oriental medicine because of its promoting effects on health and life expectancy. G. lucidum contains various compounds with a high grade of biological activty, which increase the immunity and show antitumour, antimicrobial, anti-inflammatory, antioxidant and acetylcholinesterase inhibitory activity. Several of these substances belong to the triterpenoids and polysaccharides classes. Proteins, lipids, phenols, sterols, etc. are also present. In the present review, an extensive overview of the presence of antitumour, antimicrobial, antioxidant and antiacetylcholinesterase compounds in G. lucidum extracts will be given, along with an evaluation of their therapeutic effects.

Intercalation of organic molecules into SnS{sub 2} single crystals

Energy Technology Data Exchange (ETDEWEB)

Toh, M.L.; Tan, K.J.; Wei, F.X.; Zhang, K.K.; Jiang, H. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore); Kloc, C., E-mail: ckloc@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore 639798 (Singapore)

2013-02-15

SnS{sub 2} is a layered semiconductor with a van der Waals gap separating the covalently bonded layers. In this study, post-synthesis intercalation of donor organic amine molecules, such as ethylenediamine (en), into tin disulfide and secondary intercalation of p-phenylenediamine (PPD) and 1, 5-naphthalenediamine (NDA) into SnS{sub 2e}n have been verified with X-ray diffraction. PPD and NDA did not intercalate directly even during prolonged annealing but replaced en readily if en was already present in the van der Waals gap. The c-lattice dilation is proportional to the intercalant size. Unit cell lattices of intercalated products were determined from the positions of the X-ray diffraction peaks. Optical images taken during the intercalation showed that intercalation progressed from the periphery towards the interior of the crystal. TEM diffraction patterns in the [0 0 1] direction of SnS{sub 2} after intercalation revealed defects and stacking mismatches among the SnS{sub 2} layers caused by the intercalation. UV-Vis absorption studies showed a red shift in the band edge of the SnS{sub 2} material after intercalation. The band edge was 2.2 eV for pristine SnS{sub 2}; after intercalation with en or PPD, the absorbance spectra band edges shifted to approximately 0.7 eV or 0.5 eV, respectively. - Graphical Abstract: SnS{sub 2} single crystals were intercalated with organic amine molecules such as ethylenediamine, phenylenediamine and naphthalenediamine. Absorption studies showed red shift of band edge after intercalation, which was consistent with optical observations. X-ray diffraction indicated lattice dilation in the c-lattice of SnS{sub 2} after intercalation. Highlights: Black-Right-Pointing-Pointer Organic molecules intercalated inhomogenously between covalently bonded SnS{sub 2} layers. Black-Right-Pointing-Pointer Ethylenediamine (en) intercalate directly into SnS{sub 2}. Black-Right-Pointing-Pointer Phenylenediamine (PPD) and naphthalenediamine (NDA) can be

Three-dimensional metal-intercalated covalent organic frameworks for near-ambient energy storage

Science.gov (United States)

Gao, Fei; Ding, Zijing; Meng, Sheng

2013-01-01

A new form of nanoporous material, metal intercalated covalent organic framework (MCOF) is proposed and its energy storage property revealed. Employing density functional and thermodynamical analysis, we find that stable, chemically active, porous materials could form by stacking covalent organic framework (COF) layers with metals as a gluing agent. Metal acts as active sites, while its aggregation is suppressed by a binding energy significantly larger than the corresponding cohesive energy of bulk metals. Two important parameters, metal binding and metal-metal separation, are tuned by selecting suitable building blocks and linkers when constructing COF layers. Systematic searches among a variety of elements and organic molecules identify Ca-intercalated COF with diphenylethyne units as optimal material for H2 storage, reaching a striking gravimetric density ~ 5 wt% at near-ambient conditions (300 K, 20 bar), in comparison to < 0.1 wt% for bare COF-1 under the same condition. PMID:23698018

Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review

Directory of Open Access Journals (Sweden)

Darija Cör

2018-03-01

Full Text Available Ganoderma lucidum (Reishi is a popular medicinal mushroom and has been used in oriental medicine because of its promoting effects on health and life expectancy. G. lucidum contains various compounds with a high grade of biological activty, which increase the immunity and show antitumour, antimicrobial, anti-inflammatory, antioxidant and acetylcholinesterase inhibitory activity. Several of these substances belong to the triterpenoids and polysaccharides classes. Proteins, lipids, phenols, sterols, etc. are also present. In the present review, an extensive overview of the presence of antitumour, antimicrobial, antioxidant and antiacetylcholinesterase compounds in G. lucidum extracts will be given, along with an evaluation of their therapeutic effects.

Electrochemistry of Nanostructured Intercalation Hosts

International Nuclear Information System (INIS)

Smyrl, William H.

2009-01-01

We have shown that: (1) Li+ ions are inserted reversibly, without diffusion control, up to the level of at least 4 moles Li+ ions per mole for V2O5, in the aerogel (ARG) form (500 m2/g specific surface area) and aerogel-like (ARG-L) form (200 m2/g specific surface area)(6,7,1,2); (2) polyvalent cations (Al+3, Mg+2, Zn+2) may be intercalated reversibly into V2O5 (ARG) with high capacity (approaching 4 equivalents/mole V2O5 (ARG)) for each (5); (3) dopant cations such as Ag+ and Cu+2 increase the conductivity of V2O5 (XRG) up to three orders of magnitude(3), they are electrochemically active - showing reduction to the metallic-state in parallel to intercalation of Li+ ions - but are not released to the electrolyte upon oxidation and Li+ ion release (Cu+2 ions are reduced to Cu metal and reoxidized to Cu+2 in Li+ ion insertion/release cycles, but the copper ions are not released to the electrolyte over more than 400 cycles of the XRG form); (4) we have shown that Cu+2 ion (dopant) and Zn+2 ions (chemical insertion and dopant) occupy the same intercalation site inV2O5 xerogel and aerogel(4); and (5) the reversible intercalation of Zn+2, Mg+2, and Al+3 in the ARG(11) indicates that these cations are 'mobile', but that Cu+2 ions and Ag+ ions are 'immobile' in the xerogel, i.e., the latter ions are not exchanged with the electrolyte in Li+ ion intercalation cycling(3).

Polycaprolactone nanofibres loaded with 20(S)-protopanaxadiol for in vitro and in vivo anti-tumour activity study

Science.gov (United States)

Liu, Dan-qing; Cheng, Zhi-qiang; Feng, Qing-jie; Li, He-jie; Ye, Shu-feng

2018-01-01

In this work, 20(S)-protopanaxadiol (PPD)-loaded polycaprolactone (PCL) nanofibres were successfully fabricated by the electrospinning technique using Tween 80 as a solubilizer. Firstly, smooth and continuous nanofibres were collected using suitable solvents and appropriate spinning conditions. Secondly, nanofibre mats were characterized by scanning electron microscopy, thermogravimetric (TG) analysis, Fourier transform infrared spectroscopy and mechanical testing. Finally, nanofibrous membranes were evaluated using water contact angle, in vitro drug release, biodegradation test, in vitro and in vivo anti-tumour activity and cell apoptosis assay. Scanning electron microscopic observations indicated that the diameter of the drug-loaded nanofibres increased with the increase of drug concentration. TG analysis and mechanical test showed that nanofibres were equipped with great thermal and mechanical properties. Biodegradation test exhibited that the structure of fabricated nanofibres had a certain degree of change after 15 days. An in vitro release study showed that PPD from drug-loaded nanofibres could be released in a sustained and prolonged mode. The cytotoxic effect of drug-loaded nanofibre mats examined on human laryngeal carcinoma cells (Hep-2 cells) demonstrated that the prepared nanofibres had a remarkable anti-tumour effect. Meanwhile, the drug-loaded fibre mats showed a super anti-tumour effect in an in vivo anti-tumour study. All in all, PCL nanofibres could be a potential carrier of PPD for cancer treatment. PMID:29892448

Organoelemental intercalation compounds in the system PbI2-ethan olamine

International Nuclear Information System (INIS)

Gurina, G.I.; Evtushenko, V.D.; Muraeva, O.A.; Ignatyuk, V.P.; Koshkin, V.M.

1985-01-01

Two intercalation phases with different stoichiometry in system PbI 2 -ethanolamine are identified, using the methods of IR spectroscopy, spectroscopy of diffusion reflection, X-ray phase and thermogravimetric analyses. Formation kinetics of intercalation compounds in the system, having two phases, differing in the content of intercalant in the matrix layers, is studied. In conformity with thermodynamic theory of intercalation, it is shown experimentally, that the value of a charge, transferred from intercalant molecules to the matrix layer, decreases with the increase in intercalant content in interlayer spaces

Pre-operative use of anti-TNF-alpha agents and the risk of post-operative complications in patients with Crohn's disease--a nationwide cohort study

DEFF Research Database (Denmark)

Nørgård, Bente Mertz; Nielsen, J.; Qvist, N.

2013-01-01

BACKGROUND: A possible negative role of pre-operative use of antitumour necrosis factor-alpha (anti-TNF-alpha) agents on post-operative outcomes in Crohn's disease (CD) patients is still debated. AIM: To examine the impact of pre-operative anti-TNF-alpha agents on post-operative outcomes 30 and 6...

Synthesis and characterization of Zn-Ti layered double hydroxide intercalated with cinnamic acid for cosmetic application

Science.gov (United States)

Li, Yong; Tang, Liping; Ma, Xinxu; Wang, Xinrui; Zhou, Wei; Bai, Dongsheng

2017-08-01

The use of sunscreen is recently growing and their efficacy and safety must be taken into account since they are applied on the skin frequently. In this work, an organic ultraviolet (UV) ray absorbent, cinnamic acid (CA) was intercalated into Zn-Ti layered double hydroxide (LDH) by anion-exchange reaction. ZnTi-CA-LDH, a new type of host-guest UV-blocking material has been synthesized. Detailed structural and surface morphology of ZnTi-CA-LDH were characterized by XRD, FT-IR, SEM and TEM. ZnTi-CA-LDH exhibits a superior UV blocking ability compared to pure CA and ZnTi-CO3-LDH. The thermal stability of the intercalated ZnTi-CA-LDH was investigated by TG-DTA, which showed that the thermostability of CA was markedly enhanced after intercalation into ZnTi-CO3-LDH. The EPR data showed greatly decreased photocatalytic activity compared to common inorganic UV blocking agents TiO2 and ZnO. Furthermore, the sample was formulated in a sunscreen cream to study the matrix protective effect towards UV rays.

Silica intercalated crystalline zirconium phosphate-type materials

NARCIS (Netherlands)

1988-01-01

The present invention relates to intercalated crystalline zirconium phosphate-types compositions wherein the interlayers of said composition have been intercalated with three-dimensional silicon oxide pillars whereby the pillars comprise at least two silicon atom layers parallel to the clay

Intercalated compounds of niobium and tantalum dicalcogenides

International Nuclear Information System (INIS)

Wypych, F.

1988-01-01

The synthesis of niobium and tantalum lamellar compounds and its intercalated derivatives is described. The intercalated compounds with lithium, with alkaline metal and with metals of the first-row transition are studied, characterized by X-ray diffraction. (C.G.C.) [pt

Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited

KAUST Repository

Collado Fregoso, Elisa; Hood, Samantha N.; Shoaee, Safa; Schroeder, Bob C.; McCulloch, Iain; Kassal, Ivan; Neher, Dieter; Durrant, James R.

2017-01-01

In this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.

Intercalated vs Non-Intercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited

KAUST Repository

Collado Fregoso, Elisa

2017-08-04

In this contribution, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC70BM and ICTA) as models for intercalated and non-intercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the non-intercalated system, and almost vanishes when energetic disorder is included in the model. Despite these differences, both fs-resolved transient absorption spectroscopy (TAS) and TDCF exhibit extensive first-order losses in that system, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene aggregated domains (1:4 PBTTT:PC70BM), is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges, and their impact upon charge generation and recombination.

K-intercalated carbon systems: Effects of dimensionality and substrate

KAUST Repository

Kaloni, Thaneshwor P.

2012-06-01

Density functional theory is employed to investigate the electronic properties of K-intercalated carbon systems. Young\\'s modulus indicates that the intercalation increases the intrinsic stiffness. For K-intercalated bilayer graphene on SiC(0001) the Dirac cone is maintained, whereas a trilayer configuration exhibits a small splitting at the Dirac point. Interestingly, in contrast to many other intercalated carbon systems, the presence of the SiC(0001) substrate does not suppress but rather enhances the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability for superconductivity in this system. © 2012 Europhysics Letters Association.

Sources of information on lymphoma associated with anti-tumour necrosis factor agents: comparison of published case reports and cases reported to the French pharmacovigilance system.

Science.gov (United States)

Théophile, Hélène; Schaeverbeke, Thierry; Miremont-Salamé, Ghada; Abouelfath, Abdelilah; Kahn, Valentine; Haramburu, Françoise; Bégaud, Bernard

2011-07-01

Anti-tumour necrosis factor (TNF) agents, through their intense immunoregulatory effect, have been suspected to increase the risk of malignant lymphoma. However, the classical epidemiological approaches conducted over about the last 10 years have not totally succeeded in addressing the question of a causal or artifactual association. Therefore, the analysis of a substantial set of case reports, although usually considered as poorly generalizable to the general population, could be particularly informative. Two main sources of case reports in postmarketing settings are available; publications in medical journals and reports to pharmacovigilance systems. The aim of the study was to compare the characteristics of case reports from both these sources in order to understand whether they provided the same information for the investigation of the causal link between lymphoma and anti-TNF agents. All case reports of malignant lymphoma in patients treated with an anti-TNF agent published in MEDLINE and all reports to the French pharmacovigilance system up to 1 February 2010 were identified. Cases of malignant lymphoma identified in postmarketing surveillance from both sources were compared regarding the following variables: age, sex, anti-TNF agent involved, indication for use, type of lymphoma, prior or concomitant immunosuppressive drugs and time to onset of lymphoma. A total of 81 published case reports and 61 cases reported to the French pharmacovigilance system were compared. In published reports, patients were younger (p = 0.03) and more frequently receiving a first anti-TNF treatment (p = 0.03), particularly infliximab (p = 0.03). Conversely, in the pharmacovigilance system reports, a succession of different anti-TNFs (p = 0.03) and adalimumab (p French pharmacovigilance system differed markedly for all characteristics tested, except sex and the use of prior or concomitant immunosuppressive drugs. Published case reports favoured convincing arguments

Antitumour and immunological activity of a beta 1----3/1----6 glucan from Glomerella cingulata.

Science.gov (United States)

Gomaa, K; Kraus, J; Rosskopf, F; Röper, H; Franz, G

1992-01-01

The in vivo antitumour activity of a beta 1----3/1----6 glucan from the fungus Glomerella cingulata was investigated in vivo. The glucan exhibited a strong inhibition of tumour growth of the allogeneic Sarcoma-180 as well as the syngeneic DBA/2-MC.SC-1 fibrosarcoma with inhibition ratios up to 100%. Against the hormone sensitive Noble-Nb-R prostate carcinoma the glucan alone showed a moderate antitumour effect, whereas in combination with diethylstilbestrol an almost complete regression of the tumour could be achieved. It could be demonstrated that a highly ordered structure of the glucan is not essential for the antitumour activity. Since the glucan expressed no direct cytotoxic effects, the immunomodulating activity was investigated in vitro in order to get an indication for a possible mode of action. In the lymphocyte transformation assay the glucan at a dose of 100 micrograms/ml caused a fourfold increase in the proliferation of murine spleen lymphocytes. Moreover, the glucan stimulated the phagocytosis of zymosan by bone marrow macrophages up to 100%. However, the glucan was not able to render macrophages cytotoxic against P-815 mastocytoma cells.

Charge carrier density in Li-intercalated graphene

KAUST Repository

Kaloni, Thaneshwor P.; Cheng, Yingchun; Kahaly, M. Upadhyay; Schwingenschlö gl, Udo

2012-01-01

The electronic structures of bulk C 6Li, Li-intercalated free-standing bilayer graphene, and Li-intercalated bilayer and trilayer graphene on SiC(0 0 0 1) are studied using density functional theory. Our estimate of Young's modulus suggests that Li

The potential role of cyclooxygenase-2 inhibitors in the treatment of experimentally-induced mammary tumour: does celecoxib enhance the anti-tumour activity of doxorubicin?

Science.gov (United States)

Awara, Wageh M; El-Sisi, Alaa E; El-Sayad, Magda E; Goda, Ahmed E

2004-11-01

The potential anti-tumour activity of non-steroidal anti-inflammatory drugs (NSAIDS) has been previously discussed. This study was undertaken to assess the possible anti-tumour activity of the cyclooxygenase-2 (COX-2) inhibitor; celecoxib in an animal model of mammary carcinoma; the solid Ehrlich carcinoma (SEC). The possibility that celecoxib may modulate the anti-tumour activity of doxorubicin on the SEC was also studied. Some of the possible mechanisms underlying such modulation were investigated. The anti-tumour activity of celecoxib (25 mg kg(-1)), diclofenac (12.5 mg kg(-1)) and doxorubicin (2 mg kg(-1)) either alone or in combination were investigated on SEC in vivo through the assessment of tumour growth delay (TGD) and tumour volume (TV), changes in tumour DNA content and nitric oxide (NO) levels, immunohistochemical staining of the tumour suppressor gene product; p53 histopathological examination and determination of apoptotic index of SEC. In addition, the influence of these drugs on the DNA fragmentation pattern of Ehrlich carcinoma cells (ECC) was studied. It was found that both celecoxib and diclofenac lack the anti-tumour activity on SEC. In addition there was a significant increase in doxorubicin anti-tumour activity when administered in combination with celecoxib. Moreover, it was found that both celecoxib and diclofenac have the potential to inhibit the function of P-glycoprotein (P-gp) in ECC using rhodamine uptake and efflux assays. Therefore, the current study suggested the chemosensitizing potential of celecoxib in the SEC animal model of mammary tumour, which could be explained in part on the basis of inhibition of P-gp function, with possible enhancement of doxorubicin anti-tumour activity.

Quasi-freestanding graphene on Ni(111) by Cs intercalation

KAUST Repository

Alattas, Maha Hassan Mohssen

2016-05-26

A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

Quasi-freestanding graphene on Ni(111) by Cs intercalation

KAUST Repository

Alattas, Maha Hassan Mohssen

2017-01-08

It is of technological interest to achieve quasi-freestanding graphene on a substrate. A possible approach is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which is in agreement with experiments1, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore effectively decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.

Preparation of Sulfur-Free Exfoliated Graphite by a Two-Step Intercalation Process and Its Application for Adsorption of Oils

Directory of Open Access Journals (Sweden)

Jun He

2017-01-01

Full Text Available The sulfur-free exfoliated graphite (EG was prepared by a two-step chemical oxidation process, using natural flake graphite (NFG as the precursor. The first chemical intercalation process was carried out at a temperature of 30°C for 50 min, with the optimum addition of NFG, potassium permanganate, and perchloric acid in a weight ratio of 1 : 0.4 : 10.56. Then, in the secondary intercalation step, dipotassium phosphate was employed as the intercalating agent to further increase the exfoliated volume (EV of EG. NFG, graphite intercalation compound (GIC, and EG were characterized by scanning electron microscope (SEM, energy dispersive spectrometer (EDS, X-ray diffractometer (XRD, Fourier transform infrared spectrometer (FTIR, BET surface area, and porosity analyzer. Also, the uptakes of crude oil, diesel oil, and gasoline by EG were determined. Results show that perchloric acid and hydrogen phosphate are validated to enter into the interlayer of graphite flake. The obtained EG possesses a large exfoliated volume (EV and has an excellent affinity to oils; thus, the material has rapid adsorption rates and high adsorption capacities for crude oil, diesel oil, and gasoline.

Mechanism of Si intercalation in defective graphene on SiC

KAUST Repository

Kaloni, Thaneshwor P.; Cheng, Yingchun; Schwingenschlö gl, Udo; Upadhyay Kahaly, M.

2012-01-01

Previously reported experimental findings on Si-intercalated graphene on SiC(0001) seem to indicate the possibility of an intercalation process based on the migration of the intercalant through atomic defects in the graphene sheet. We employ density

Selective coal mining of intercalated lignite deposits

Energy Technology Data Exchange (ETDEWEB)

Zunic, R [Kolubara-Projekt, Lazarevac (Yugoslavia)

1991-01-01

Describes selective coal mining in the Tamnava-Istocno Polje coal surface coal mine (Yugoslavia), designed for an annual coal production of 11.4 Mt. Until 1991, this mine exploited one thick lignite seam, without spoil intercalations, using a bucket wheel excavator-conveyor-spreader system both for coal mining and removal of overburden. In the future, several spoil intercalations of up to 1.0 m and thicker will appear with a total volume of 22 million m{sup 3}. These intercalations have to be selectively excavated in order to guarantee the calorific value of coal for the Nikola Tesla power plant. Computer calculations were carried out to determine the decrease in excavator coal production due to selective mining of spoil strata. Calculations found that the annual surface mine capacity will be lower by at most 9%, depending on thickness of spoil intercalations. The useful operation time of excavators will be reduced by 98 hours per year. The planned annual coal production will nevertheless be fulfilled. 3 refs.

Sodium-Ion Intercalated Transparent Conductors with Printed Reduced Graphene Oxide Networks.

Science.gov (United States)

Wan, Jiayu; Gu, Feng; Bao, Wenzhong; Dai, Jiaqi; Shen, Fei; Luo, Wei; Han, Xiaogang; Urban, Daniel; Hu, Liangbing

2015-06-10

In this work, we report for the first time that Na-ion intercalation of reduced graphene oxide (RGO) can significantly improve its printed network's performance as a transparent conductor. Unlike pristine graphene that inhibits Na-ion intercalation, the larger layer-layer distance of RGO allows Na-ion intercalation, leading to simultaneously much higher DC conductivity and higher optical transmittance. The typical increase of transmittance from 36% to 79% and decrease of sheet resistance from 83k to 311 Ohms/sq in the printed network was observed after Na-ion intercalation. Compared with Li-intercalated graphene, Na-ion intercalated RGO shows much better environmental stability, which is likely due to the self-terminating oxidation of Na ions on the RGO edges. This study demonstrated the great potential of metal-ion intercalation to improve the performance of printed RGO network for transparent conductor applications.

Oncolytic measles virus enhances antitumour responses of adoptive CD8+NKG2D+ cells in hepatocellular carcinoma treatment.

Science.gov (United States)

Chen, Aiping; Zhang, Yonghui; Meng, Gang; Jiang, Dengxu; Zhang, Hailin; Zheng, Meihong; Xia, Mao; Jiang, Aiqin; Wu, Junhua; Beltinger, Christian; Wei, Jiwu

2017-07-12

There is an urgent need for novel effective treatment for hepatocellular carcinoma (HCC). Oncolytic viruses (OVs) not only directly lyse malignant cells, but also induce potent antitumour immune responses. The potency and precise mechanisms of antitumour immune activation by attenuated measles virus remain unclear. In this study, we investigated the potency of the measles virus vaccine strain Edmonston (MV-Edm) in improving adoptive CD8 + NKG2D + cells for HCC treatment. We show that MV-Edm-infected HCC enhanced the antitumour activity of CD8 + NKG2D + cells, mediated by at least three distinct mechanisms. First, MV-Edm infection compelled HCC cells to express the specific NKG2D ligands MICA/B, which may contribute to the activation of CD8 + NKG2D + cells. Second, MV-Edm-infected HCC cells stimulated CD8 + NKG2D + cells to express high level of FasL resulting in enhanced induction of apoptosis. Third, intratumoural administration of MV-Edm enhanced infiltration of intravenously injected CD8 + NKG2D + cells. Moreover, we found that MV-Edm and adoptive CD8 + NKG2D + cells, either administered alone or combined, upregulated the immune suppressive enzyme indoleamine 2,3-dioxygenase 1 (IDO1) in HCC. Elimination of IDO1 by fludarabine enhanced antitumour responses. Taken together, our data provide a novel and clinically relevant strategy for treatment of HCC.

Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism

Science.gov (United States)

Yang, Wei; Bai, Yibing; Xiong, Ying; Zhang, Jin; Chen, Shuokai; Zheng, Xiaojun; Meng, Xiangbo; Li, Lunyi; Wang, Jing; Xu, Chenguang; Yan, Chengsong; Wang, Lijuan; Chang, Catharine C. Y.; Chang, Ta-Yuan; Zhang, Ti; Zhou, Penghui; Song, Bao-Liang; Liu, Wanli; Sun, Shao-cong; Liu, Xiaolong; Li, Bo-liang; Xu, Chenqi

2016-01-01

CD8+ T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment1–4. Reactivating the cytotoxicity of CD8+ T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8+ T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme5, led to potentiated effector function and enhanced proliferation of CD8+ but not CD4+ T cells. This is due to the increase in the plasma membrane cholesterol level of CD8+ T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8+ T cells were better than wild-type CD8+ T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile6,7, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy. PMID:26982734

Adsorption of Phosphate Ion in Water with Lithium-Intercalated Gibbsite

OpenAIRE

Riwandi Sihombing; Yuni Krisyuningsih Krisnandi; Rahma Widya; Siti Zahrotul Luthfiyah; Rika Tri Yunarti

2015-01-01

In order to enhance adsorption capacity of gibbsite (Al(OH)3 as an adsorbent for the adsorption of phosphate in water, gibbsite was modified through lithium-intercalation. The purification method of Tributh and Lagaly was applied prior to intercalation. The Li-Intercalation was prepared by the dispersion of gibbsite into LiCl solution for 24 hours. This intercalation formed an cationic clay with the structure of [LiAl2(OH)6]+ and exchangeable Cl- anions in the gibbsite interlayer. A phosphate...

Structural effects on the electronic characteristics of intramolecularly intercalated alkali-rubrene complexes

International Nuclear Information System (INIS)

Li, Tsung-Lung; Lu, Wen-Cai

2016-01-01

The geometric and electronic structures of neutral monolithium- and monosodium-rubrene (Li 1 Rub and Na 1 Rub) isomers are investigated and compared with monopotassium-rubrene (K 1 Rub). Based on the alkali binding site, all isomers of these alkali-rubrene complexes can be subdivided into two types: intramolecularly intercalated and extramolecularly adsorbed. The minimum-energy Li 1 Rub and Na 1 Rub are intercalated structures, whereas the minimum-energy K 1 Rub is adsorbed. The fact that the intercalated Li 1 Rub and Na 1 Rub structures are energetically favorable over the adsorbed ones can be explained by two energy rules. First, “double” proximity of the intercalating alkali element to a pair of phenyl side groups enormously reduces the total energy. Second, accommodation of a minuscule intercalant does not significantly deform the carbon frame and, thus, increases the energy only by a small amount. Additionally, the peculiar effects of intramolecular intercalation on the electronic structures of molecules are also studied in this simulation of monoalkali intercalation. In the monoalkali-intercalated rubrene complex, only one of the two pairs of phenyl groups of rubrene is intercalated, intentionally leaving another pair pristine, which facilitates the comparison of electronic structures between the intercalated and pristine pairs of phenyl side groups in a single molecule. The uniformity of chemical environments of the phenyl groups of the intercalated Li 1 Rub/Na 1 Rub is deteriorated by the incorporation of the intercalant, and leads to their spectral characteristics in contrast to K 1 Rub. In particular, the introduction of the intercalant promotes the carbon 2p orbitals of the intercalated phenyl pair to take part in the electronic structures of the HOMO and LUMO peaks of Li 1 Rub/Na 1 Rub. The unpaired electron in the HOMO is delocalized over the backbone with higher probability of distributing over the central two fused rings than over the outer two

New kaolinite phases expanded through intercalation with potassium acetate

International Nuclear Information System (INIS)

Frost, R.L.; Kristof, J.; Kloprogge, J.T.

1998-01-01

Full text: Changes in the hydroxyl surfaces of potassium acetate-intercalated kaolinite have been studied over the ambient to predehydroxylation temperature range using a combination of X-ray diffraction and Raman spectroscopy. Upon intercalation, the kaolinite expanded along the c-axis direction to 13.88 Angstroms. Upon heating the intercalation complex over the 50 to 300 deg C range, X-ray diffraction shows the existence of three additional intercalation phases with d-spacings of 9.09, 9.60, and 11.47 Angstroms. The amount of each phase is temperature dependent. These expansions are reversible and upon cooling the intercalation complex returned to its original spacing. The 13.88 Angstroms phase only existed in the presence of water. It is proposed that the expanded kaolinite intercalation phases result from the orientation of the acetate within the intercalation complex. The Raman spectra of the hydroxyl-stretching region (Frost and van der Gaast, 1997) of potassium acetate-intercalated kaolinite has been obtained under an atmosphere of both air and nitrogen using a thermal stage over the 25 to 300 deg C temperature range (Johansson et al., 1998). Raman spectra of the C-C, C=O stretching and O-C-O bending modes show that at least two types of acetate are present in the intercalation complex. These are assigned to two different orientations of the acetate. At 25 deg C, a new band at 3606 cm -1 attributed to the inner surface hydroxyl hydrogen bonded to the acetate ion is observed with a concomitant loss of intensity in the bands attributed to the inner surface hydroxyls (Frost and Kristof, 1997, Frost et al.,1997). Heating the intercalation complex to 50 deg C results in two hydroxyl-stretching frequencies at 3594 and 3604 cm -1 . This change in frequencies is ascribed to phase changes of the potassium acetate-intercalated kaolinite. At 100 deg C, the bands shift to 3600 and 3613 cm -1 . These shifts in frequencies are assigned to new kaolinite expanded phases. At

Intercalation of paracetamol into the hydrotalcite-like host

International Nuclear Information System (INIS)

Kovanda, František; Maryšková, Zuzana; Kovář, Petr

2011-01-01

Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg–Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals. - Graphical abstract: Molecular simulations showed disordered arrangement of paracetamol molecules in the interlayer; most of the interlayer water molecules are located near the hydroxide sheets.▪ Highlights: ► Paracetamol was intercalated in Mg–Al hydrotalcite-like host by rehydration/reconstruction procedure. ► Paracetamol phenolic groups interact with positively charged sites in hydroxide sheets. ► Molecular simulations showed disordered arrangement of guest molecules in the interlayer. ► Slower release of paracetamol intercalated in the hydrotalcite-like host was observed.

Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

International Nuclear Information System (INIS)

Arízaga, Gregorio Guadalupe Carbajal

2012-01-01

Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn 5 (OH) 8 Cl 2 ·2H 2 O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C. - Graphical abstract: The zinc hydroxide chloride (ZHC) with formula Zn 5 (OH) 8 Cl 2 ·2H 2 O was tested as intercalation matrix. In comparison with the well-known zinc hydroxide nitrate (ZHN) and layered double hydroxides (LDH), ZHC was the best matrix for thermal protection of Asp combustion, presenting exothermic peaks even at 452 °C, while the highest exothermic event in ZHN was at 366 °C, and in the LDH it was at 276 °C. Highlights: ► Zinc hydroxide chloride (ZHC) was tested as intercalation matrix for the first time. ► ZHC has higher chemical and thermal stability than zinc hydroxide nitrate and LDH. ► NH 3 molecules can be intercalated into ZHC. ► The amino group of amino acids limits the intercalation by ion-exchange.

Manipulation of Dirac cones in metal-intercalated epitaxial graphene

Science.gov (United States)

Wang, Cai-Zhuang; Kim, Minsung; Tringides, Michael; Ho, Kai-Ming

Graphene is one of the most attractive materials from both fundamental and practical points of view due to its characteristic Dirac cones. The electronic property of graphene can be modified through the interaction with substrate or another graphene layer as illustrated in few-layer epitaxial graphene. Recently, metal intercalation became an effective method to manipulate the electronic structure of graphene by modifying the coupling between the constituent layers. In this work, we show that the Dirac cones of epitaxial graphene can be manipulated by intercalating rare-earth metals. We demonstrate that rare-earth metal intercalated epitaxial graphene has tunable band structures and the energy levels of Dirac cones as well as the linear or quadratic band dispersion can be controlled depending on the location of the intercalation layer and density. Our results could be important for applications and characterizations of the intercalated epitaxial graphene. Supported by the U.S. DOE-BES under Contract No. DE-AC02-07CH11358.

Mechanism of Si intercalation in defective graphene on SiC

KAUST Repository

Kaloni, Thaneshwor P.

2012-10-01

Previously reported experimental findings on Si-intercalated graphene on SiC(0001) seem to indicate the possibility of an intercalation process based on the migration of the intercalant through atomic defects in the graphene sheet. We employ density functional theory to show that such a process is in fact feasible and obtain insight into its details. By means of total energy and nudged elastic band calculations we are able to establish the mechanism on an atomic level and to determine the driving forces involved in the different steps of the intercalation process through atomic defects.

A formulation of pancreatic pro-enzymes provides potent anti-tumour efficacy: a pilot study focused on pancreatic and ovarian cancer.

Science.gov (United States)

Perán, Macarena; López-Ruiz, Elena; García, María Ángel; Nadaraia-Hoke, Shorena; Brandt, Ralf; Marchal, Juan A; Kenyon, Julian

2017-10-25

Proteolytic enzymes have shown efficacy in cancer therapy. We present a combination of the two pro-enzymes Trypsinogen and Chymotrypsinogen A with potent in vitro and in vivo anti-tumour efficacy. A synergetic anti-tumour effect for Trypsinogen and Chymotrypsinogen A was determined at a ratio 1:6 (named PRP) using 24 human cancer cell lines. The antiangiogenic effect of PRP was analysed by matrigel-based tube formation and by fibrous capsule formation assays. Furthermore, cell invasion and wound healing assays together with qRT-PCR determination of epithelial-to-mesenchymal transition (EMT) markers were performed on human cancer cells treated with PRP. Additionally, in vivo pharmacokinetic studies were implemented and the PRP's anti-tumour efficacy was explored against orthotopic pancreatic and ovarian cancer tumours. PRP formulation was proven to inhibit in vitro angiogenesis, tumour growth, cancer cell migration and invasiveness; and to be an effective and well tolerated in vivo anti-tumour treatment. Finally, the clinical efficacy of a suppository formulation containing both pancreatic pro-enzymes in the context of a UK Pharmaceuticals Special Scheme was evaluated in advanced cancer patients. Consequently, PRP could have relevant oncological clinical applications for the treatment of advanced or metastatic pancreatic adenocarcinoma and advanced epithelial ovarian cancer.

Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

International Nuclear Information System (INIS)

Kanzaki, Y.; Konuma, M.; Matsumoto, O.

1981-01-01

The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS 2 amd NbS 2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS 2 and vice versa in those of NbS 2 . (orig.)

Structural effects on the electronic characteristics of intramolecularly intercalated alkali-rubrene complexes

Energy Technology Data Exchange (ETDEWEB)

Li, Tsung-Lung, E-mail: quantum@mail.ncyu.edu.tw [Department of Electrophysics, National Chia-Yi University, 300 Hsueh-Fu Road, Chiayi, 60004, Taiwan, ROC (China); Lu, Wen-Cai, E-mail: wencailu@jlu.edu.cn [Laboratory of Fiber Materials and Modern Textile, Growing Base for State Key Laboratory, College of Physics, Qingdao University, Qingdao, Shandong 266071 (China); State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130021 (China)

2016-11-01

The geometric and electronic structures of neutral monolithium- and monosodium-rubrene (Li{sub 1} Rub and Na{sub 1} Rub) isomers are investigated and compared with monopotassium-rubrene (K{sub 1} Rub). Based on the alkali binding site, all isomers of these alkali-rubrene complexes can be subdivided into two types: intramolecularly intercalated and extramolecularly adsorbed. The minimum-energy Li{sub 1} Rub and Na{sub 1} Rub are intercalated structures, whereas the minimum-energy K{sub 1} Rub is adsorbed. The fact that the intercalated Li{sub 1} Rub and Na{sub 1} Rub structures are energetically favorable over the adsorbed ones can be explained by two energy rules. First, “double” proximity of the intercalating alkali element to a pair of phenyl side groups enormously reduces the total energy. Second, accommodation of a minuscule intercalant does not significantly deform the carbon frame and, thus, increases the energy only by a small amount. Additionally, the peculiar effects of intramolecular intercalation on the electronic structures of molecules are also studied in this simulation of monoalkali intercalation. In the monoalkali-intercalated rubrene complex, only one of the two pairs of phenyl groups of rubrene is intercalated, intentionally leaving another pair pristine, which facilitates the comparison of electronic structures between the intercalated and pristine pairs of phenyl side groups in a single molecule. The uniformity of chemical environments of the phenyl groups of the intercalated Li{sub 1} Rub/Na{sub 1} Rub is deteriorated by the incorporation of the intercalant, and leads to their spectral characteristics in contrast to K{sub 1} Rub. In particular, the introduction of the intercalant promotes the carbon 2p orbitals of the intercalated phenyl pair to take part in the electronic structures of the HOMO and LUMO peaks of Li{sub 1} Rub/Na{sub 1} Rub. The unpaired electron in the HOMO is delocalized over the backbone with higher probability of

Ultrahigh intercalation pseudocapacitance of mesoporous orthorhombic niobium pentoxide from a novel cellulose nanocrystal template

International Nuclear Information System (INIS)

Kong, Lingping; Zhang, Chuangfang; Wang, Jitong; Long, Donghui; Qiao, Wenming; Ling, Licheng

2015-01-01

A facile biotemplating method has been developed to prepare mesoporous orthorhombic nobium pentoxide (T-Nb 2 O 5 ) films with ultrahigh lithium ion (Li + ) intercalation pseudocapacitance. Nanorod-like cellulose nanocrystals (CNs) with 5–10 nm in width and 100–300 nm in length are produced by the hydrolysis of cotton, which can serve as a novel soft templating agent enabling the straightforward synthesis of mesoporous T-Nb 2 O 5 films. By varying the niobic-to-template ratio, it is possible to tune the surface area and crystallite dimension of the Nb 2 O 5 films. The obtained T-Nb 2 O 5 films show typical capacitive-dominated behaviour in the sweep rate range of 1–20 mV s −1 . It delivers an initial intercalation capacity of 644 C g −1 at a current density of 0.625 A g −1 , corresponding to x = 1.83 for Li x Nb 2 O 5 , and can still keep relatively stable capacity of 560 C g −1 after 300 cycles. Moreover, its excellent high-rate capability (450 C g −1 at 12.5 A g −1 ) and wider temperature adaptability present here suggests the promising of T-Nb 2 O 5 as high-energy pseudocapacitor electrode with superior intercalation capacitive behaviour. - Graphical abstract: We developed a facile and sustainable method to prepare T-Nb 2 O 5 nanocrystals using novel nanorod-like cellulose nanocrystals (CNs) as soft templates. The T-Nb 2 O 5 nanocrystals exhibited unprecedented Li + intercalation pseudocapacitance, excellent cycle performance and good high-and-low temperature tolerance performance.

Intercalation of alcohols in Ag sulfonates: topotactic behavior despite flexible layers.

Science.gov (United States)

Côté, Adrien P; Ferguson, Michael J; Khan, Kashif A; Enright, Gary D; Kulynych, Angela D; Dalrymple, Sean A; Shimizu, George K H

2002-01-28

This article presents the inaugural intercalation study of a layered metal sulfonate network. Silver triflate forms intercalation complexes with straight chain primary alcohols from ethanol (C(2)H(5)OH) to eicosanol (C(20)H(41)OH). Single-crystal data for the EtOH adduct, 1, are presented which show that the intercalation is coordinative to Ag. In contrast to many other layered hosts, no preheating of Ag triflate is required to liberate a coordination site for intercalation to take place, owing to the ability of the triflate ion to reorient. Crystal structure parameters for 1: C(4)H(6)F(6)S(2)O(7)Ag(2), a = 5.345(7) A, b = 11.310(2) A, c = 12.004(2) A, alpha = 116.87(1) degrees, beta = 90.46(1) degrees, gamma = 99.59(1) degrees, triclinic, space group P, Z = 2. Intercalate 1 presents the triflate ion in an unprecedented mu(5)-coordination mode. PXRD data on the family of complexes show that the intercalation is topotactic, as verified by the linear increase in d-spacing and calculated c-axis lengths for the intercalates, with increasing chain length. The data also show that the alcohol intercalates adopt an interdigitated rather than bilayer arrangement.

Effectiveness of Co intercalation between Graphene and Ir(1 1 1)

Science.gov (United States)

Carlomagno, I.; Drnec, J.; Scaparro, A. M.; Cicia, S.; Mobilio, S.; Felici, R.; Meneghini, C.

2018-04-01

Graphene can be used to avoid the oxidation of metallic films. This work explores the effectiveness of such stabilizing effect on Cobalt (Co) films intercalated between Graphene and Ir(1 1 1). After intercalation at 300 °C, two Co films are exposed to ambient pressure and investigated using Co-K edge X-ray Absorption Near Edge Spectroscopy. The formation of a disordered oxide phase is observed, and associated to the presence of some non-intercalated Co. Further annealing at 500 °C causes the oxide reduction to metallic Co which further intercalates below the Graphene. Once the intercalation is completed, Graphene prevents the Co from oxidation under ambient pressure conditions.

Dynamics of Intercalation/De-Intercalation of Rhodamine B during the Polymorphic Transformation of CdAl Layered Double Hydroxide to the Brucite-Like Cadmium Hydroxide

KAUST Repository

Saliba, Daniel

2016-06-23

Cadmium-Aluminum layered double hydroxide (CdAl LDH) is thermodynamically unstable and transforms to Cd(OH)2 and Al(OH)3 in a short period of time. We present a reaction-diffusion framework that enables us to use in situ steady-state fluorescence spectroscopy to study the kinetics of intercalation of a fluorescent probe (Rhodamine B (RhB)) during the formation of the CdAl LDH and its de-intercalation upon the conversion of the LDH phase to the β phase (Cd(OH)2). The method involves the diffusion of sodium hydroxide into a hydrogel gel matrix containing the aluminum and cadmium ions as well as the species we wish to incorporate in the interlayers of the LDH. The existence of RhB between the LDH layers and its expel during the transition into the β phase are proved via fluorescence microscopy, XRD and ssNMR. The activation energies of intercalation and de-intercalation of RhB are computed and show dependence on the cationic ratio of the corresponding LDH. We find that the energies of de- intercalation are systematically higher than those of intercalation proving that the dyes are stabilized due to the probe-brucite sheets interactions.

Dynamics of Intercalation/De-Intercalation of Rhodamine B during the Polymorphic Transformation of CdAl Layered Double Hydroxide to the Brucite-Like Cadmium Hydroxide

KAUST Repository

Saliba, Daniel; Ezzeddine, Alaa; Emwas, Abdul-Hamid M.; Khashab, Niveen M.; Al-Ghoul, Mazen

2016-01-01

Cadmium-Aluminum layered double hydroxide (CdAl LDH) is thermodynamically unstable and transforms to Cd(OH)2 and Al(OH)3 in a short period of time. We present a reaction-diffusion framework that enables us to use in situ steady-state fluorescence spectroscopy to study the kinetics of intercalation of a fluorescent probe (Rhodamine B (RhB)) during the formation of the CdAl LDH and its de-intercalation upon the conversion of the LDH phase to the β phase (Cd(OH)2). The method involves the diffusion of sodium hydroxide into a hydrogel gel matrix containing the aluminum and cadmium ions as well as the species we wish to incorporate in the interlayers of the LDH. The existence of RhB between the LDH layers and its expel during the transition into the β phase are proved via fluorescence microscopy, XRD and ssNMR. The activation energies of intercalation and de-intercalation of RhB are computed and show dependence on the cationic ratio of the corresponding LDH. We find that the energies of de- intercalation are systematically higher than those of intercalation proving that the dyes are stabilized due to the probe-brucite sheets interactions.

Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

Science.gov (United States)

Arízaga, Gregorio Guadalupe Carbajal

2012-01-01

Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

Intercalation and Exfoliation of Kaolinite with Sodium Dodecyl Sulfate

Directory of Open Access Journals (Sweden)

Xiaochao Zuo

2018-03-01

Full Text Available Kaolinite (Kaol was intercalated with dimethyl sulfoxide (DMSO and subsequently methanol (MeOH to prepare intercalation compounds Kaol-DMSO and Kaol-MeOH. Kaol-MeOH was used as an intermediate to synthesize Kaol-sodium dodecyl sulfate (SDS intercalation compound (Kaol-SDS via displacement reaction. The ultrasonic exfoliation of Kaol-SDS produced a resultant Kaol-SDS-U. The samples were characterized by X-ray diffraction (XRD, Fourier transformation infrared spectroscopy (FTIR, thermal analysis, scanning electronic microscopy (SEM, transmission electron microscopy (TEM and particle size analysis. The results revealed that the intercalation of sodium dodecyl sulfate into kaolinite layers caused an obvious increase of the basal spacing from 0.72–4.21 nm. The dehydroxylation temperature of Kaol-SDS was obviously lower than that of original kaolinite. During the intercalation process of sodium dodecyl sulfate, a few kaolinite layers were exfoliated and curled up from the edges of the kaolinite sheets. After sonication treatment, the kaolinite layers were further transformed into nanoscrolls, and the exfoliated resultant Kaol-SDS-U possessed a smaller particle size close to nanoscale.

Highly n -doped graphene generated through intercalated terbium atoms

Science.gov (United States)

Daukiya, L.; Nair, M. N.; Hajjar-Garreau, S.; Vonau, F.; Aubel, D.; Bubendorff, J. L.; Cranney, M.; Denys, E.; Florentin, A.; Reiter, G.; Simon, L.

2018-01-01

We obtained highly n -type doped graphene by intercalating terbium atoms between graphene and SiC(0001) through appropriate annealing in ultrahigh vacuum. After terbium intercalation angle-resolved-photoelectron spectroscopy (ARPES) showed a drastic change in the band structure around the K points of the Brillouin zone: the well-known conical dispersion band of a graphene monolayer was superposed by a second conical dispersion band of a graphene monolayer with an electron density reaching 1015cm-2 . In addition, we demonstrate that atom intercalation proceeds either below the buffer layer or between the buffer layer and the monolayer graphene. The intercalation of terbium below a pure buffer layer led to the formation of a highly n -doped graphene monolayer decoupled from the SiC substrate, as evidenced by ARPES and x-ray photoelectron spectroscopy measurements. The band structure of this highly n -doped monolayer graphene showed a kink (a deviation from the linear dispersion of the Dirac cone), which has been associated with an electron-phonon coupling constant one order of magnitude larger than those usually obtained for graphene with intercalated alkali metals.

PYRENE INTERCALATING NUCLEIC ACIDS WITH A CARBON LINKER

DEFF Research Database (Denmark)

Østergaard, Michael E.; Wamberg, Michael Chr.; Pedersen, Erik Bjerregaard

2011-01-01

geminally attached. Fluorescence studies of this intercalating nucleic acid with the pyrene moieties inserted as a bulge showed formation of an excimer band. When a mismatch was introduced at the site of the intercalator, an excimer band was formed for the destabilized duplexes whereas an exciplex band...

Intercalation of paracetamol into the hydrotalcite-like host

Science.gov (United States)

Kovanda, František; Maryšková, Zuzana; Kovář, Petr

2011-12-01

Hydrotalcite-like compounds are often used as host structures for intercalation of various anionic species. The product intercalated with the nonionic, water-soluble pharmaceuticals paracetamol, N-(4-hydroxyphenyl)acetamide, was prepared by rehydration of the Mg-Al mixed oxide obtained by calcination of hydrotalcite-like precursor at 500 °C. The successful intercalation of paracetamol molecules into the interlayer space was confirmed by powder X-ray diffraction and infrared spectroscopy measurements. Molecular simulations showed that the phenolic hydroxyl groups of paracetamol interact with hydroxide sheets of the host via the hydroxyl groups of the positively charged sites of Al-containing octahedra; the interlayer water molecules are located mostly near the hydroxide sheets. The arrangement of paracetamol molecules in the interlayer is rather disordered and interactions between neighboring molecules cause their tilting towards the hydroxide sheets. Dissolution tests in various media showed slower release of paracetamol intercalated in the hydrotalcite-like host in comparison with tablets containing the powdered pharmaceuticals.

Soft-chemical synthesis and catalytic activity of Ni-Al and Co-Al layered double hydroxides (LDHs intercalated with anions with different charge density

Directory of Open Access Journals (Sweden)

Takahiro Takei

2014-09-01

Full Text Available Co-Al and Ni-Al layered double hydroxides (LDHs intercalated with three types of anionic molecules, dodecylsulfate (C12H25SO4−, DS, di-2-ethylsulfosuccinate ([COOC2H3EtBu]2C2H3SO3−, D2ES, and polytungstate (H2W12O4210−, HWO were prepared by means of ion-exchange and co-precipitation processes. With the use of DS and D2ES as intercalation agents, high crystallinity was maintained after intercalation into the LDHs. In the case of HWO, the intercalated LDHs could be obtained by ion-exchange as well as co-precipitation with a decline in the crystallinity; however, unreacted LDH was detected in the ion-exchange samples, and some unwanted phases such as hydroxide and pyrochlore were generated by the co-precipitation process. The maximum specific surface area and pore volume of the Ni-Al sample with intercalated HWO, prepared by the ion-exchange process were 74 m2/g and 0.174 mL/g, respectively. The occupancies of DS, D2ES, and HWO within the interlayer space were approximately 0.3–0.4, 0.5–0.6, and 0.1–0.2, respectively, in the Co-Al and Ni-Al LDHs. Analysis of the catalytic activity demonstrated that the DS-intercalated Ni-Al LDH sample exhibited relatively good catalytic activity for conversion of cyclohexanol to cyclohexanone.

Quasi-freestanding graphene on Ni(111) by Cs intercalation

KAUST Repository

Alattas, Maha Hassan Mohssen; Schwingenschlö gl, Udo

2016-01-01

A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory

Reaction of nitriles intercalation in tantalum pentachloride complexes with amines

International Nuclear Information System (INIS)

Glushkova, M.A.; Chumaevskij, N.A.; Khmelevskaya, L.V.; Ershova, M.M.; Buslaev, Yu.A.

1987-01-01

Data on the study of aceto-, propio- and benzonitrile intercalation in TaCl 5 complexes with diethyl- and triethylamines in CCl 4 solution are discussed. Using the methods of IR and Raman spectroscopy it has been established that it is the nature of ligand, and not nitrile intercalated in the complex, that affects greatly the composition of final products. In contrast to acetonitrile, intercalation in the complex of propio- and benzonitriles is observed already at room temperature. On the basis of spectral data a supposition is made that carbon tetrachloride used as a solvent accelerates the reaction of nitrile intercalation and promotes their deprotonation in the presence of aprotonic amine

Prediction of superconductivity in Li-intercalated bilayer phosphorene

International Nuclear Information System (INIS)

Huang, G. Q.; Xing, Z. W.; Xing, D. Y.

2015-01-01

It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T c can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor

Prediction of superconductivity in Li-intercalated bilayer phosphorene

Energy Technology Data Exchange (ETDEWEB)

Huang, G. Q. [Department of Physics, Nanjing Normal University, Nanjing 210023 (China); National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Xing, Z. W., E-mail: zwxing@nju.edu.cn [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xing, D. Y. [National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093 (China); Collaborative Innovation Center of Advanced Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

2015-03-16

It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature T{sub c} can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor.

Quasi-freestanding graphene on Ni(111) by Cs intercalation

KAUST Repository

Alattas, Maha Hassan Mohssen; Schwingenschlö gl, Udo

2017-01-01

It is of technological interest to achieve quasi-freestanding graphene on a substrate. A possible approach is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) is investigated using density functional theory

Spin labeled amino acid nitrosourea derivatives--synthesis and antitumour activity.

Science.gov (United States)

Zheleva, A; Raikov, Z; Ilarionova, M; Todorov, D

1995-01-01

The synthesis of three spin labeled derivatives of N-[N'-(chloroethyl)-N'-nitrosocarbamoyl] amino acids is reported. The new nitrosoureas are obtained by condensation of the corresponding N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl] amino acid with 2,2,6,6-tetramethyl-1-oxyl-4-aminopiperidine using dicyclohexylcarbodiimide. Their chemical structures are confirmed by elemental analysis, IR, MS, and EPR spectroscopy. All newly synthesized compounds showed high antitumour activity against the lymphoid leukemia L1210 in BDF1 mice.

Formation of intercalation compound of kaolinite-glycine via displacing guest water by glycine.

Science.gov (United States)

Zheng, Wan; Zhou, Jing; Zhang, Zhenqian; Chen, Likun; Zhang, Zhongfei; Li, Yong; Ma, Ning; Du, Piyi

2014-10-15

The kaolinite-glycine intercalation compound was successfully formed by displacing intercalated guest water molecules in kaolinite hydrate as a precursor. The microstructure of the compound was characterized by X-ray diffraction, Fourier Transform Infrared Spectroscopy and Scanning Electron Microscope. Results show that glycine can only be intercalated into hydrated kaolinite to form glycine-kaolinite by utilizing water molecules as a transition phase. The intercalated glycine molecules were squeezed partially into the ditrigonal holes in the silicate layer, resulting in the interlayer distance of kaolinite reaching 1.03nm. The proper intercalation temperature range was between 20°C and 80°C. An intercalation time of 24h or above was necessary to ensure the complete formation of kaolinite-glycine. The highest intercalation degree of about 84% appeared when the system was reacted at the temperature of 80°C for 48h. There were two activation energies for the intercalation of glycine into kaolinite, one being 21kJ/mol within the temperature range of 20-65°C and the other 5.8kJ/mol between 65°C and 80°C. The intercalation degree (N) and intercalation velocity (v) of as a function of intercalation time (t) can be empirically expressed as N=-79.35e(-)(t)(/14.8)+80.1 and v=5.37e(-)(t)(/14.8), respectively. Copyright © 2014 Elsevier Inc. All rights reserved.

Intercalated organic-inorganic perovskites stabilized by fluoroaryl-aryl interactions.

Science.gov (United States)

Mitzi, David B; Medeiros, David R; Malenfant, Patrick R L

2002-04-22

Crystals of several new hybrid tin(II) iodide-based perovskites, involving 2,3,4,5,6- pentafluorophenethylammonium or phenethylammonium cation bilayers and intercalated aryl or perfluoroaryl molecules, were grown by slow evaporation of a methanol solution containing the hybrid perovskite and the intercalating species. The (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) structure was solved at -75 degrees C in a monoclinic C2/c subcell [a = 41.089(12) A, b = 6.134(2) A, c = 12.245(3) A, beta = 94.021(5) degrees, Z = 4] and consists of sheets of corner-sharing distorted SnI(6) octahedra separated by bilayers of pentafluorophenethylammonium cations. The intercalated benzene molecules form a single well-ordered layer interposed between adjacent fluoroaryl cation layers. The corresponding hybrid with an unfluorinated organic cation and fluorinated intercalating molecule, (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)), is isostructural [a = 40.685(4) A, b = 6.0804(6) A, c = 12.163(1) A, beta = 93.136(2) degrees, Z = 4]. For each intercalated system, close C...C contacts (3.44-3.50 A) between the aromatic cation and the intercalated molecule are indicative of a significant face-to-face interaction, similar to that found in the complex C(6)H(6).C(6)F(6). Crystal growth runs with the organic cation and prospective intercalating molecule either both fluorinated or both unfluorinated did not yield stable intercalated compounds, demonstrating the significance of fluoroaryl-aryl interactions in the current intercalated structures. Thermal analysis of (C(6)F(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)H(6)) and (C(6)H(5)C(2)H(4)NH(3))(2)SnI(4).(C(6)F(6)) crystals yields, in addition to the characteristic transitions of the parent perovskite, endothermic transitions [12.6(5) and 32.1(8) kJ/mol, respectively] with an onset at 145 degrees C and a weight loss corresponding to the complete loss of the intercalated molecule. The relatively high deintercalation temperature (well above the boiling point of

Adsorption of Phosphate Ion in Water with Lithium-Intercalated Gibbsite

Directory of Open Access Journals (Sweden)

Riwandi Sihombing

2015-12-01

Full Text Available In order to enhance adsorption capacity of gibbsite (Al(OH3 as an adsorbent for the adsorption of phosphate in water, gibbsite was modified through lithium-intercalation. The purification method of Tributh and Lagaly was applied prior to intercalation. The Li-Intercalation was prepared by the dispersion of gibbsite into LiCl solution for 24 hours. This intercalation formed an cationic clay with the structure of [LiAl2(OH6]+ and exchangeable Cl- anions in the gibbsite interlayer. A phosphate adsorption test using Lithium-intercalated gibbsite (LIG resulted in optimum adsorption occurring at pH 4.5 with an adsorption capacity of 11.198 mg phosphate/g LIG which is equivalent with 1.04 wt% LIG. The adsorption capacity decreased with decreasing amounts of H2PO4-/HPO4- species in the solution. This study showed that LIG has potential as an adsorbent for phosphate in an aqueous solution with pH 4.5–9.5.

Ultrahigh intercalation pseudocapacitance of mesoporous orthorhombic niobium pentoxide from a novel cellulose nanocrystal template

Energy Technology Data Exchange (ETDEWEB)

Kong, Lingping; Zhang, Chuangfang; Wang, Jitong; Long, Donghui, E-mail: longdh@mail.ecust.edu.cn; Qiao, Wenming; Ling, Licheng

2015-01-15

A facile biotemplating method has been developed to prepare mesoporous orthorhombic nobium pentoxide (T-Nb{sub 2}O{sub 5}) films with ultrahigh lithium ion (Li{sup +}) intercalation pseudocapacitance. Nanorod-like cellulose nanocrystals (CNs) with 5–10 nm in width and 100–300 nm in length are produced by the hydrolysis of cotton, which can serve as a novel soft templating agent enabling the straightforward synthesis of mesoporous T-Nb{sub 2}O{sub 5} films. By varying the niobic-to-template ratio, it is possible to tune the surface area and crystallite dimension of the Nb{sub 2}O{sub 5} films. The obtained T-Nb{sub 2}O{sub 5} films show typical capacitive-dominated behaviour in the sweep rate range of 1–20 mV s{sup −1}. It delivers an initial intercalation capacity of 644 C g{sup −1} at a current density of 0.625 A g{sup −1}, corresponding to x = 1.83 for Li{sub x}Nb{sub 2}O{sub 5}, and can still keep relatively stable capacity of 560 C g{sup −1} after 300 cycles. Moreover, its excellent high-rate capability (450 C g{sup −1} at 12.5 A g{sup −1}) and wider temperature adaptability present here suggests the promising of T-Nb{sub 2}O{sub 5} as high-energy pseudocapacitor electrode with superior intercalation capacitive behaviour. - Graphical abstract: We developed a facile and sustainable method to prepare T-Nb{sub 2}O{sub 5} nanocrystals using novel nanorod-like cellulose nanocrystals (CNs) as soft templates. The T-Nb{sub 2}O{sub 5} nanocrystals exhibited unprecedented Li{sup +} intercalation pseudocapacitance, excellent cycle performance and good high-and-low temperature tolerance performance.

Effect of propylene-graft-maleic anhydride and the co-intercalant cis-13- docosenamide on the structure and mechanical properties of PP/organoclay clay systems; Efeito do polipropileno enxertado com anidrido maleico e do co-intercalante cis-13-docosenamida na estrutura e propriedades mecanicas de sistemas PP/argila organofilica

Energy Technology Data Exchange (ETDEWEB)

Silva Neto, J.E. da; Almeida, T.G.; Leite, R.C.N.; Carvalho, L.H., E-mail: joaoemidio2@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Alves, T.S. [Universidade Federal do Piaui, PI (Brazil)

2014-07-01

In this work, PP/organoclay hybrids were prepared by melt intercalation and the effect of adding different amounts of a compatibilizer (PP-G-MA) and a co-intercalating agent (cis-13-docosenamide) to maximize the compatibility between filler and the polymeric matrix were investigated. The systems were processed under a single condition on a co-rotating twin screw extruder. The morphology and mechanical properties of the nanocomposites were investigated. The hybrids were characterized by x-ray diffraction, tensile (ASTM D638) and impact properties (ASTM D256). The results indicated an approximately 45% increase of the basal interplanar distance d{sub (001)} of the clay on hybrid systems, containing both compatibilizing and co-intercalating agents, forming intercalated structures. The tensile strength of the systems was not affected significantly by compatibilizer and/or co-intercalant addition, however, increases of up to 30% in elastic modulus and 48% in impact strength were obtained. (author)

Physical and chemical studies of superconduction properties of the intercalation compounds

International Nuclear Information System (INIS)

Eder, F.X.; Lerf, A.

1980-01-01

The superconducting properties of the intercalation compounds of layered dichalcogenides were studied. Our studies were concerned mainly to the alkali metal intercalation derivatives of TaS 2 and NbS 2 , and later on extended to the molecule intercalation compounds. The main difficulties with this class of superconductors result from varying material properties; these are therefore the subject of broad intensity in our investigations. The results received on the physical and chemical properties of the intercalation compounds is utilized for a phenomenological description of the factors mainly determining there superconducting properties. (orig.) [de

Synthesis and stability of Br2, ICl and IBr intercalated pitch-based graphite fibers

Science.gov (United States)

Wessbecher, Dorothy E.; Forsman, William C.; Gaier, James R.

1988-01-01

The intercalation of halogens in pitch-based fiber is studied as well as the stability of the resultant intercalation compounds. It is found that IBr intercalates P-100 to yield a high-sigma GIC with attractive stability properties. During ICl intercalation, the presence of O2 interferes with the reaction and necessitates a higher threshold pressure for intercalation.

HALLOYSITE INTERCALATION OF NORTHWEST ANATOLIA

Directory of Open Access Journals (Sweden)

Bülent BAŞARA

2015-11-01

Full Text Available In this study, the representative samples were taken from the halloysite deposits located in Çanakkale-Balıkesir regions, in NW Anatolia. At first, the dehydration temperatures of the samples were determined after sample preparation and characterization studies. It was found that halloysite samples began to lose their interlayer waters at 50°C and continued up to 70°C. The intercalation studies were carried out on dehydrated samples by using ethylene glycol, potassium acetate, dimethyl sulfoxide and formamide. Although there were negative results by ethylene glycol and potassium acetate, the satisfactory results were obtained by dimethyl sulfoxide and formamide. It was understood that the most effective reagent in terms of intercalation was formamide.

Intercalation of metals and silicon at the interface of epitaxial graphene and its substrates

International Nuclear Information System (INIS)

Huang Li; Xu Wen-Yan; Que Yan-De; Mao Jin-Hai; Meng Lei; Pan Li-Da; Li Geng; Wang Ye-Liang; Du Shi-Xuan; Gao Hong-Jun; Liu Yun-Qi

2013-01-01

Intercalations of metals and silicon between epitaxial graphene and its substrates are reviewed. For metal intercalation, seven different metals have been successfully intercalated at the interface of graphene/Ru(0001) and form different intercalated structures. Meanwhile, graphene maintains its original high quality after the intercalation and shows features of weakened interaction with the substrate. For silicon intercalation, two systems, graphene on Ru(0001) and on Ir(111), have been investigated. In both cases, graphene preserves its high quality and regains its original superlative properties after the silicon intercalation. More importantly, we demonstrate that thicker silicon layers can be intercalated at the interface, which allows the atomic control of the distance between graphene and the metal substrates. These results show the great potential of the intercalation method as a non-damaging approach to decouple epitaxial graphene from its substrates and even form a dielectric layer for future electronic applications. (topical review - low-dimensional nanostructures and devices)

Critical role of DNA intercalation in enzyme-catalyzed nucleotide flipping

Science.gov (United States)

Hendershot, Jenna M.; O'Brien, Patrick J.

2014-01-01

Nucleotide flipping is a common feature of DNA-modifying enzymes that allows access to target sites within duplex DNA. Structural studies have identified many intercalating amino acid side chains in a wide variety of enzymes, but the functional contribution of these intercalating residues is poorly understood. We used site-directed mutagenesis and transient kinetic approaches to dissect the energetic contribution of intercalation for human alkyladenine DNA glycosylase, an enzyme that initiates repair of alkylation damage. When AAG flips out a damaged nucleotide, the void in the duplex is filled by a conserved tyrosine (Y162). We find that tyrosine intercalation confers 140-fold stabilization of the extrahelical specific recognition complex, and that Y162 functions as a plug to slow the rate of unflipping by 6000-fold relative to the Y162A mutant. Surprisingly, mutation to the smaller alanine side chain increases the rate of nucleotide flipping by 50-fold relative to the wild-type enzyme. This provides evidence against the popular model that DNA intercalation accelerates nucleotide flipping. In the case of AAG, DNA intercalation contributes to the specific binding of a damaged nucleotide, but this enhanced specificity comes at the cost of reduced speed of nucleotide flipping. PMID:25324304

Tuning the electronic structure of graphene through alkali metal and halogen atom intercalation

Science.gov (United States)

Ahmad, Sohail; Miró, Pere; Audiffred, Martha; Heine, Thomas

2018-04-01

The deposition, intercalation and co-intercalation of heavy alkali metals and light halogens atoms in graphene mono- and bilayers have been studied using first principles density-functional calculations. Both the deposition and the intercalation of alkali metals gives rise to n-type doping due to the formation of M+-C- pairs. The co-intercalation of a 1:1 ratio of alkali metals and halogens derives into the formation of ionic pairs among the intercalated species, unaltering the electronic structure of the layered material.

Theological Implications of Markan Interpretative Intercalations

Directory of Open Access Journals (Sweden)

Mateusz Kusio

2015-09-01

Full Text Available This paper aims at evidencing the thesis that Markan interpretative intercalations are a narrative structure that manifests profound theological engagement of the evangelist. This device is defined as an entanglement of two storylines in the A1–B–A2 pattern which by using the notions of simultaneity, contrast, irony, similarity, etc. offers a wholly novel meaning of the stories. Six intercalations of the St Mark’s gospel – 3 : 20–35; 5 : 21–43; 6 : 7–31; 11 : 12–23; 14 : 1–11, 53–72 – merge different episodes with distinct theological purposes and as such cannot be reduced to the rank of a literary or redactional device. All of them are concerned with the most essential topics of the Markan theology, such as Christology, especially in relation to suffering, requirements of true discipleship, vision of the future ecclesiastical community. St Mark in his intercalations reveals his elaborated, clear-cut theology, as well as narrative ingenuity and mastery.

Strain Lattice Imprinting in Graphene by C60 Intercalation at the Graphene/Cu Interface

NARCIS (Netherlands)

Monazami, Ehsan; Bignardi, Luca; Rudolf, Petra; Reinke, Petra

2015-01-01

Intercalation of C60 molecules at the graphene-substrate interface by annealing leads to amorphous and crystalline intercalated structures. A comparison of topography and electronic structure with wrinkles and moiré patterns confirms intercalation. The intercalated molecules imprint a local

Targeting multiple cannabinoid anti-tumour pathways with a resorcinol derivative leads to inhibition of advanced stages of breast cancer.

Science.gov (United States)

Murase, Ryuichi; Kawamura, Rumi; Singer, Eric; Pakdel, Arash; Sarma, Pranamee; Judkins, Jonathon; Elwakeel, Eiman; Dayal, Sonali; Martinez-Martinez, Esther; Amere, Mukkanti; Gujjar, Ramesh; Mahadevan, Anu; Desprez, Pierre-Yves; McAllister, Sean D

2014-10-01

The psychoactive cannabinoid Δ(9) -tetrahydrocannabinol (THC) and the non-psychoactive cannabinoid cannabidiol (CBD) can both reduce cancer progression, each through distinct anti-tumour pathways. Our goal was to discover a compound that could efficiently target both cannabinoid anti-tumour pathways. To measure breast cancer cell proliferation/viability and invasion, MTT and Boyden chamber assays were used. Modulation of reactive oxygen species (ROS) and apoptosis was measured using dichlorodihydrofluorescein and annexin/propidium iodide, respectively, in combination with cell flow cytometry. Changes in protein levels were evaluated using Western analysis. Orthotopic and i.v. mouse models of breast cancer metastasis were used to test the activity of cannabinoids in vivo. CBD reduced breast cancer metastasis in advanced stages of the disease as the direct result of down-regulating the transcriptional regulator Id1. However, this was associated with moderate increases in survival. We therefore screened for analogues that could co-target cannabinoid anti-tumour pathways (CBD- and THC-associated) and discovered the compound O-1663. This analogue inhibited Id1, produced a marked stimulation of ROS, up-regulated autophagy and induced apoptosis. Of all the compounds tested, it was the most potent at inhibiting breast cancer cell proliferation and invasion in culture and metastasis in vivo. O-1663 prolonged survival in advanced stages of breast cancer metastasis. Developing compounds that can simultaneously target multiple cannabinoid anti-tumour pathways efficiently may provide a novel approach for the treatment of patients with metastatic breast cancer. © 2014 The British Pharmacological Society.

Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

Energy Technology Data Exchange (ETDEWEB)

Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Mercante, Luiza A. [Laboratório Nacional de Nanotecnologia para o Agronegócio (LNNA), Embrapa Instrumentação, São Carlos, SP 13560 970 (Brazil); Soriano, Stéphane [Instituto de Física, Universidade Federal Fluminense, Niterói, RJ 24.210 346 (Brazil); Andruh, Marius [Inorganic Chemistry Laboratory, Faculty of Chemistry, University of Bucharest, Str. Dumbrava Rosie nr. 23, Bucharest (Romania); Vieira, Méri D., E-mail: gqimeri@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil); Vaz, Maria G.F., E-mail: mariavaz@vm.uff.br [Instituto de Química, Universidade Federal Fluminense, Niterói, RJ 24.020–150 (Brazil)

2015-08-15

In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar space of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.

Atomic force microscopy study of anion intercalation into highly oriented pyrolytic graphite

Energy Technology Data Exchange (ETDEWEB)

Alliata, D; Haering, P; Haas, O; Koetz, R [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Siegenthaler, H [University of Berne (Switzerland)

1999-08-01

In the context of ion transfer batteries, we studied highly oriented pyrolytic graphite (HOPG) in perchloric acid, as a model to elucidate the mechanism of electrochemical intercalation in graphite. Aim of the work is the local and time dependent investigation of dimensional changes of the host material during electrochemical intercalation processes on the nanometer scale. We used atomic force microscopy (AFM), combined with cyclic voltammetry, as in-situ tool of analysis during intercalation and expulsion of perchloric anions into the HOPG electrodes. According to the AFM measurements, the HOPG interlayer spacing increases by 32% when perchloric anions intercalate, in agreement with the formation of stage IV of graphite intercalation compounds. (author) 3 figs., 3 refs.

First-Principles Study of Lithium and Sodium Atoms Intercalation in Fluorinated Graphite

Directory of Open Access Journals (Sweden)

Fengya Rao

2015-06-01

Full Text Available The structure evolution of fluorinated graphite (CFx upon the Li/Na intercalation has been studied by first-principles calculations. The Li/Na adsorption on single CF layer and intercalated into bulk CF have been calculated. The better cycling performance of Na intercalation into the CF cathode, comparing to that of Li intercalation, is attributed to the different strength and characteristics of the Li-F and Na-F interactions. The interactions between Li and F are stronger and more localized than those between Na and F. The strong and localized Coulomb attraction between Li and F atoms breaks the C−F bonds and pulls the F atoms away, and graphene sheets are formed upon Li intercalation.

On lunisolar calendars and intercalation schemes in Southeast Asia

Science.gov (United States)

Gislén, Lars

2018-04-01

This is a survey of different calendar intercalation schemes, mainly in Southeast Asia. The Thai and Burmese Calendars, superficially very similar, are shown to have quite different and interesting intercalation schemes. We also investigate similarities between the original Burmese Calendar and the Romakasiddhânta from India.

Polysulfide intercalated layered double hydroxides for metal capture applications

Energy Technology Data Exchange (ETDEWEB)

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

A ruthenium polypyridyl intercalator stalls DNA replication forks, radiosensitizes human cancer cells and is enhanced by Chk1 inhibition

Science.gov (United States)

Gill, Martin R.; Harun, Siti Norain; Halder, Swagata; Boghozian, Ramon A.; Ramadan, Kristijan; Ahmad, Haslina; Vallis, Katherine A.

2016-08-01

Ruthenium(II) polypyridyl complexes can intercalate DNA with high affinity and prevent cell proliferation; however, the direct impact of ruthenium-based intercalation on cellular DNA replication remains unknown. Here we show the multi-intercalator [Ru(dppz)2(PIP)]2+ (dppz = dipyridophenazine, PIP = 2-(phenyl)imidazo[4,5-f][1,10]phenanthroline) immediately stalls replication fork progression in HeLa human cervical cancer cells. In response to this replication blockade, the DNA damage response (DDR) cell signalling network is activated, with checkpoint kinase 1 (Chk1) activation indicating prolonged replication-associated DNA damage, and cell proliferation is inhibited by G1-S cell-cycle arrest. Co-incubation with a Chk1 inhibitor achieves synergistic apoptosis in cancer cells, with a significant increase in phospho(Ser139) histone H2AX (γ-H2AX) levels and foci indicating increased conversion of stalled replication forks to double-strand breaks (DSBs). Normal human epithelial cells remain unaffected by this concurrent treatment. Furthermore, pre-treatment of HeLa cells with [Ru(dppz)2(PIP)]2+ before external beam ionising radiation results in a supra-additive decrease in cell survival accompanied by increased γ-H2AX expression, indicating the compound functions as a radiosensitizer. Together, these results indicate ruthenium-based intercalation can block replication fork progression and demonstrate how these DNA-binding agents may be combined with DDR inhibitors or ionising radiation to achieve more efficient cancer cell killing.

Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

Energy Technology Data Exchange (ETDEWEB)

Yi, Tanghong; Chen, Wei; Cheng, Lei; Bayliss, Ryan D.; Lin, Feng; Plews, Michael R.; Nordlund, Dennis; Doeff, Marca M.; Persson, Kristin A.; Cabana, Jordi (LBNL); (SLAC); (UIC); (UCB)

2017-02-07

Reversible intercalation reactions provide the basis for modern battery electrodes. Despite decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials A_xK_1–xFeF₃ (A = Li, Na). By starting with KFeF₃, approximately 75% of K⁺ ions were subsequently replaced by Li⁺ and Na⁺ through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopy confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe^2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. This study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.

Intercalation compounds of NbSe2 und SnSe2. Model systems for low-dimensional superconductors

International Nuclear Information System (INIS)

Herzinger, Michael

2013-01-01

Quasi-two-dimensional (2D) metal dichalcogenides have received considerable research interest since their complex anisotropic electronic properties can be controlled by the intercalation of donor species. Although layered dichalcogenides have been studied by many aspects of chemical and physical properties, their two-dimensional character is only poorly understood. The present work deals with the layer-shaped dichalcogenides SnSe 2 and NbSe 2 . The host-material SnSe 2 was synthesized by chemical transport with Iodine as transport agent in sealed quartz ampoules. The intercalation of the semiconducting layered single crystals SnSe 2 with the organometallic compound cobaltocene (CoCp 2 ) leads to superconductivity up to T = 8 K. Ex-situ intercalation studies show an intercalation-mechanism outgoing from the host material 2H-SnSe 2 in a stage-2 phase which goes over in a stage-1 phase for higher intercalation degrees. In addition, SnSe 2 {CoCp 2 } x show remarkable low-temperature properties e.g. the coexistence of superconductivity and magnetism in dependence of the staging and cobaltocene-content of the material. Starting from an intercalation degree of 17% CoCp 2 long range ordered magnetism (with increasing saturation magnetization) was observed in 18R-SnSe 2 {CoCp 2 } x . Furthermore SnSe 2 {CoCp 2 } x show an extremely sensitive superconducting pinning behavior in very small magnetic fields partially below B 2 -content. A phase diagram was developed in dependence of the degree of intercalation over the whole range of intercalation between 0 % and 33 %. For comparison of the low-temperature character of SnSe 2 {CoCp 2 } x , another layer-shaped superconductor NbSe 2 was intercalated with CoCp 2 . The layered high-k s-wave superconductor 2H-NbSe 2 belongs to the most prominent low-dimensional materials studied during the past fifty years. After the discovery of the high temperature superconductor MgB 2 , a benchmark system for multi-band superconductivity, NbSe 2

Ge-intercalated graphene: The origin of the p-type to n-type transition

KAUST Repository

Kaloni, Thaneshwor P.

2012-09-01

Recently huge interest has been focussed on Ge-intercalated graphene. In order to address the effect of Ge on the electronic structure, we study Ge-intercalated free-standing C 6 and C 8 bilayer graphene, bulk C 6Ge and C 8Ge, as well as Ge-intercalated graphene on a SiC(0001) substrate, by density functional theory. In the presence of SiC(0001), there are three ways to obtain n-type graphene: i) intercalation between C layers; ii) intercalation at the interface to the substrate in combination with Ge deposition on the surface; and iii) cluster intercalation. All other configurations under study result in p-type states irrespective of the Ge coverage. We explain the origin of the different doping states and establish the conditions under which a transition occurs. © Copyright EPLA, 2012.

Lithium isotope effect accompanying electrochemical intercalation of lithium into graphite

CERN Document Server

Yanase, S; Oi, T

2003-01-01

Lithium has been electrochemically intercalated from a 1:2 (v/v) mixed solution of ethylene carbonate (EC) and methylethyl carbonate (MEC) containing 1 M LiClO sub 4 into graphite, and the lithium isotope fractionation accompanying the intercalation was observed. The lighter isotope was preferentially fractionated into graphite. The single-stage lithium isotope separation factor ranged from 1.007 to 1.025 at 25 C and depended little on the mole ratio of lithium to carbon of the lithium-graphite intercalation compounds (Li-GIC) formed. The separation factor increased with the relative content of lithium. This dependence seems consistent with the existence of an equilibrium isotope effect between the solvated lithium ion in the EC/MEC electrolyte solution and the lithium in graphite, and with the formation of a solid electrolyte interfaces on graphite at the early stage of intercalation. (orig.)

Hybrid n-Alkylamine Intercalated Layered Titanates for Solid Lubrication

NARCIS (Netherlands)

Gonzalez Rodriguez, P.; Yuan, H.; van den Nieuwenhuijzen, Karin Jacqueline Huberta; Lette, W.; Schipper, Dirk J.; ten Elshof, Johan E.

2016-01-01

The intercalation of different primary n-alkylamines in the structure of a layered titanate of the lepidocrocite type (H1.07Ti1.73O4) for application in high-temperature solid lubrication is reported. The intercalation process of the amines was explored by means of in situ small-angle X-ray

Study on intercalation of ionic liquid into montmorillonite and its property evaluation

International Nuclear Information System (INIS)

Takahashi, Chisato; Shirai, Takashi; Fuji, Masayoshi

2012-01-01

Present study report fabrication of a solid–liquid intercalated compound using montmorillonite and ionic liquid [IL; 1-Butyl-3-methylimidazolium tetrafluoroborate; ([BMIM][BF 4 ])]. The intercalation of IL into the interlayer of montmorillonite was revealed by swelling behavior measured by X-ray diffraction (XRD) and cation exchange capacity (CEC). The crystal swelling structure of intercalation compound was further evidenced by transmission electron microscope (TEM). From these results, the arrangement of [BMIM] + ions (cationic part of IL) into the unit layer were proposed. Furthermore, the montmorillonite showed electrical conductivity with the aid of IL. This demonstrates a successful attempt to fabricate a solid–liquid state nano-structure compound as possible transparent electrically conducting thin film. -- Highlights: ► Direct intercalation of ionic liquid into the montmorillonite was studied. ► The crystal swelling structure in liquid state was successfully characterized by TEM. ► We proposed the atomic arrangement of intercalated compound using ionic liquid. ► Ionic liquid is useful for fabricating an intercalated compound with electrical-conductivity.

Preparation of graphite intercalation compounds containing oligo and polyethers

Science.gov (United States)

Zhang, Hanyang; Lerner, Michael M.

2016-02-01

Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets.Layered host-polymer nanocomposites comprising polymeric guests between inorganic sheets have been prepared with many inorganic hosts, but there is limited evidence for the incorporation of polymeric guests into graphite. Here we report for the first time the preparation, and structural and compositional characterization of graphite intercalation compounds (GICs) containing polyether bilayers. The new GICs are obtained by either (1) reductive intercalation of graphite with an alkali metal in the presence of an oligo or polyether and an electrocatalyst, or (2) co-intercalate exchange of an amine for an oligo or polyether in a donor-type GIC. Structural characterization of products using powder X-ray diffraction, Raman spectroscopy, and thermal analyses supports the formation of well-ordered, first-stage GICs containing alkali metal cations and oligo or polyether bilayers between reduced graphene sheets. Electronic supplementary information (ESI) available: Domain size, additional Raman spectra info, compositional calculation, and packing fractions. See DOI: 10.1039/c5

Understanding Mn-Based Intercalation Cathodes from Thermodynamics and Kinetics

Directory of Open Access Journals (Sweden)

Yin Xie

2017-07-01

Full Text Available A series of Mn-based intercalation compounds have been applied as the cathode materials of Li-ion batteries, such as LiMn2O4, LiNi1−x−yCoxMnyO2, etc. With open structures, intercalation compounds exhibit a wide variety of thermodynamic and kinetic properties depending on their crystal structures, host chemistries, etc. Understanding these materials from thermodynamic and kinetic points of view can facilitate the exploration of cathodes with better electrochemical performances. This article reviews the current available thermodynamic and kinetic knowledge on Mn-based intercalation compounds, including the thermal stability, structural intrinsic features, involved redox couples, phase transformations as well as the electrical and ionic conductivity.

High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

KAUST Repository

Koski, Kristie J.; Cha, Judy J.; Reed, Bryan W.; Wessells, Colin D.; Kong, Desheng; Cui, Yi

2012-01-01

A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

High-Density Chemical Intercalation of Zero-Valent Copper into Bi 2 Se 3 Nanoribbons

KAUST Repository

Koski, Kristie J.

2012-05-09

A major goal of intercalation chemistry is to intercalate high densities of guest species without disrupting the host lattice. Many intercalant concentrations, however, are limited by the charge of the guest species. Here we have developed a general solution-based chemical method for intercalating extraordinarily high densities of zero-valent copper metal into layered Bi 2Se 3 nanoribbons. Up to 60 atom % copper (Cu 7.5Bi 2Se 3) can be intercalated with no disruption to the host lattice using a solution disproportionation redox reaction. © 2012 American Chemical Society.

The preliminary feasibility of intercalated graphite railgun armatures

International Nuclear Information System (INIS)

Gaier, J.R.; Yashan, D.; Naud, S.

1991-01-01

This paper reports on graphite intercalation compounds which may provide an excellent material for the fabrication of electro-magnetic railgun armatures. As a pulse of power is fed into the armature the intercalate could be excited into the plasma state around the edges of the armature, while the bulk of the current would be carried through the graphite block. Such an armature would have desirable characteristics of both diffuse plasma armatures and bulk conduction armatures. In addition, the highly anisotropic nature of these materials could enable the electrical and thermal conductivity to be tailored to meet the specific requirements of electromagnetic railgun armatures. Preliminary investigations have been performed in an attempt to determine the feasibility of using graphite intercalation compounds as railgun armatures. Issues of fabrication, resistivity, stability, and electrical current spreading have been addressed for the case of highly oriented pyrolytic graphite

Kinetics and mechanism of ionic intercalation/de-intercalation during the formation of α-cobalt hydroxide and its polymorphic transition to β-cobalt hydroxide: Reaction-diffusion framework

KAUST Repository

Rahbani, Janane; Khashab, Niveen M.; Patra, Digambara; Al-Ghoul, Mazen

2012-01-01

We study the kinetics and mechanism of intercalation and de-intercalation of small anions during the formation of crystalline α-Co(OH) 2 and its transformation to β-Co(OH) 2 within a reaction-diffusion framework. We therein use fluorescence spectroscopy with Rhodamine 6G (Rh6G) as a probe as well as other spectroscopic and imaging techniques. The method is based on the reaction and diffusion of hydroxide ions into a gel matrix containing the Co(ii) ions, the conjugate anions to be intercalated and Rh6G. The advantage of this simple method is that it allows us to separate throughout space the various stages during the formation of α-Co(OH) 2 and its transformation to β-Co(OH) 2, thus enabling fluorescence measurements of the those stages by simply focusing on different areas of the tube. It also permits us to extract with ease the solids for characterization and image analysis. The macroscopic evolution of the system, which consists of a leading blue front designating the formation of α-Co(OH) 2 followed by a sharp blue/pink interface designating the transformation to the pink β-Co(OH) 2, exhibits different dynamics depending on the anion present in the gel. At a certain stage, the blue/pink interface stops its propagation and only the blue front continues. This represents clear evidence of the dependence of the kinetics of intercalation and de-intercalation on the nature of the anion. The coexisting polymorphs were collected and characterized using XRD, FTIR, Raman and UV-Vis. The fluorescence images of the α-Co(OH) 2 reveal clearly the presence of Rh6G between its layers, whereas images from the β polymorph indicate the opposite. Moreover, the fluorescence of Rh6G is monitored during the formation of α-Co(OH) 2 and its conversion to β-Co(OH) 2. During the formation, the fluorescence intensity and lifetime are significantly increased whereas the opposite happens during the transformation to the β phase. We are able to calculate the activation energies

Structure and antitumour activity of fucoidan isolated from sporophyll of Korean brown seaweed Undaria pinnatifida

Czech Academy of Sciences Publication Activity Database

Synytsya, A.; Kim, W. J.; Kim, S. M.; Pohl, Radek; Synytsya, Al.; Kvasnička, F.; Čopíková, J.; Park, Y. I.

2010-01-01

Roč. 81, č. 1 (2010), s. 41-48 ISSN 0144-8617 Institutional research plan: CEZ:AV0Z40550506 Keywords : fucoidan from sporophyll Undaria pinnatifida * structure * antitumour activity Subject RIV: CC - Organic Chemistry Impact factor: 3.463, year: 2010

Decreasing the electronic confinement in layered perovskites through intercalation.

Science.gov (United States)

Smith, Matthew D; Pedesseau, Laurent; Kepenekian, Mikaël; Smith, Ian C; Katan, Claudine; Even, Jacky; Karunadasa, Hemamala I

2017-03-01

We show that post-synthetic small-molecule intercalation can significantly reduce the electronic confinement of 2D hybrid perovskites. Using a combined experimental and theoretical approach, we explain structural, optical, and electronic effects of intercalating highly polarizable molecules in layered perovskites designed to stabilize the intercalants. Polarizable molecules in the organic layers substantially alter the optical and electronic properties of the inorganic layers. By calculating the spatially resolved dielectric profiles of the organic and inorganic layers within the hybrid structure, we show that the intercalants afford organic layers that are more polarizable than the inorganic layers. This strategy reduces the confinement of excitons generated in the inorganic layers and affords the lowest exciton binding energy for an n = 1 perovskite of which we are aware. We also demonstrate a method for computationally evaluating the exciton's binding energy by solving the Bethe-Salpeter equation for the exciton, which includes an ab initio determination of the material's dielectric profile across organic and inorganic layers. This new semi-empirical method goes beyond the imprecise phenomenological approximation of abrupt dielectric-constant changes at the organic-inorganic interfaces. This work shows that incorporation of polarizable molecules in the organic layers, through intercalation or covalent attachment, is a viable strategy for tuning 2D perovskites towards mimicking the reduced electronic confinement and isotropic light absorption of 3D perovskites while maintaining the greater synthetic tunability of the layered architecture.

Removal of lead from aqueous solution on glutamate intercalated layered double hydroxide

Directory of Open Access Journals (Sweden)

Shen Yanming

2017-05-01

Full Text Available Glutamate intercalated Mg–Al layered double hydroxide (LDH was prepared by co-precipitation and the removal of Pb2+ in the aqueous solution was investigated. The prepared samples were characterized by XRD, FT-IR and SEM. It was shown that glutamate can intercalate into the interlayer space of Mg–Al LDH. The glutamate intercalated Mg–Al LDH can effectively adsorb Pb2+ in the aqueous solution with an adsorption capacity of 68.49 mg g−1. The adsorption of Pb2+ on glutamate intercalated Mg–Al LDH fitted the pseudo-second-order kinetics model and the isotherm can be well defined by Langmuir model.

Interlayer Structure of Bioactive Molecule, 2-Aminoethanesulfonate, Intercalated into Calcium-Containing Layered Double Hydroxides

Directory of Open Access Journals (Sweden)

Tae-Hyun Kim

2012-01-01

Full Text Available We have successfully intercalated 2-aminoethanesulfonate, a well-known biomolecule taurine, into calcium-containing layered double hydroxides via optimized solid phase intercalation. According to X-ray diffraction patterns and infrared spectroscopy, it was revealed that the intercalated taurine molecules were each directly coordinated to other calcium cation and arranged in a zig-zag pattern. Scanning electron microscopy showed that the particle size and morphology of the LDHs were not affected by the solid phase intercalation, and the surface of intercalates was covered by organic moieties. From ninhydrin amine detection tests, we confirmed that most of the taurine molecules were well stabilized between the calcium-containing LDH layers.

Thermoelectric Properties of Li-Intercalated ZrSe₂ Single Crystals

DEFF Research Database (Denmark)

Holgate, Tim; Liu, Yufei; Hitchcock, Dale

2013-01-01

Zirconium diselenide (ZrSe2) is one of many members of the layer-structured transition-metal dichalcogenide family. The structure of these materials features a weakly bonded van der Waals gap between covalently bonded CdI2-type atomic layers that may host a wide range of intercalants. Intercalation......, and low cost of such materials, merit further thermoelectric investigations of intercalated zirconium diselenide, especially in conjunction with a substitutional doping approach....

Improved antiangiogenic and antitumour activity of the combination of the natural flavonoid fisetin and cyclophosphamide in Lewis lung carcinoma-bearing mice

Science.gov (United States)

Touil, Yasmine S.; Seguin, Johanne; Scherman, Daniel; Chabot, Guy G.

2011-01-01

Purpose The natural flavonoid fisetin was recently identified as a lead compound that stabilizes endothelial cell microtubules. In this study we investigated the antiproliferative and antiangiogenic properties of fisetin in vitro and in vivo. Methods Fisetin cytotoxicity was evaluated using Lewis lung carcinoma cells (LLC), endothelial cells and NIH 3T3 cells. Endothelial cell (EC) migration and capillary-like structure formation were evaluated using EAhy 926 cells. In vivo tumour growth inhibition studies were performed using LLC bearing mice treated with fisetin and/or cyclophosphamide (CPA). Results The fisetin IC50 was 59 μM for LLC and 77 μM for EC cells, compared to 210 μM for normal NIH 3T3 cells (24 h). Fisetin inhibited EC migration and capillary-like structure formation at non-cytotoxic concentrations (22–44 μM). In mice, fisetin inhibited angiogenesis assessed using the Matrigel plug assay. In LLC bearing mice, fisetin produced a 67% tumour growth inhibition (223 mg/kg, intraperitoneal), similar to the 66% produced by low dose CPA (30 mg/kg, subcutaneous). When fisetin and CPA were combined, however, a marked improvement in antitumour activity was observed (92% tumour growth inhibition), with low systemic toxicity. Tumour histology showed decreased microvessel density with either fisetin or CPA alone, and a dramatic decrease after the fisetin/CPA combination. Conclusions We have shown that fisetin not only displays in vitro and in vivo antiangiogenic properties, but that it can also markedly improve the in vivo antitumour effect of CPA. We propose that this drug combination associating a non-toxic dietary flavonoid with a cytotoxic agent could advantageously be used in the treatment of solid tumours. PMID:21069336

Synthesis of graphite intercalation compound of group VI metals and uranium hexafluorides

International Nuclear Information System (INIS)

Fukui, Toshihiro; Hagiwara, Rika; Ema, Keiko; Ito, Yasuhiko

1993-01-01

Systematic investigations were made on the synthesis of graphite intercalation compounds of group VI transition metals (W and Mo) and uranium hexafluorides. The reactions were performed by interacting liquid or gaseous metal hexafluorides with or without elemental fluorine at ambient temperature. The degree of intercalation of these metal fluorides depends on the formation enthalpy of fluorometallate anion from the original metal hexafluoride, as has been found for other intercalation reactions of metal fluorides. (author)

Antitumour activity of cordycepin in mice.

Science.gov (United States)

Yoshikawa, Noriko; Nakamura, Kazuki; Yamaguchi, Yu; Kagota, Satomi; Shinozuka, Kazumasa; Kunitomo, Masaru

2004-12-01

1. The antitumour effect of orally administered cordycepin, a component isolated from water extracts of Cordyceps sinensis, was examined in mice inoculated with B16 melanoma (B16-BL6) cells. 2. B16-BL6 (1 x 10(6)) cells were inoculated subcutaneously into the right footpad of mice. At 2 weeks after the cell inoculation, the enlarged primary tumour lump was weighed. Cordycepin (0, 5 and 15 mg/kg per day) was administered orally to the mice for 2 weeks from the date of tumour inoculation. Cordycepin (15 mg/kg per day) significantly reduced by 36% the wet weight of the primary tumour lump compared to that of the untreated control mice, without any loss of bodyweight or systemic toxicity. 3. Cordycepin (15 mg/kg per day) administered orally for 2 weeks inhibited the tumour enlargement in the right thigh inoculated with B16-BL6 cells premixed with extracellular matrix (Matrigel). 4. These results indicate that orally administered cordycepin inhibits melanoma cell growth in mice with no adverse effects.

Synthesis of graphene nanoplatelets from peroxosulfate graphite intercalation compounds

OpenAIRE

MELEZHYK A.V.; TKACHEV A.G.

2014-01-01

Ultrasonic exfoliation of expanded graphite compound obtained by cold expansion of graphite intercalated with peroxodisulfuric acid was shown to allow the creation of graphene nanoplatelets with thickness of about 5-10 nm. The resulting graphene material contained surface oxide groups. The expanded graphite intercalation compound was exfoliated by ultrasound much easier than thermally expanded graphite. A mechanism for the cleavage of graphite to graphene nanoplatelets is proposed. It include...

Intercalation of papain enzyme into hydrotalcite type layered double hydroxide

Science.gov (United States)

Zou, N.; Plank, J.

2012-09-01

Intercalation of proteolytic enzyme papain into hydrotalcite type LDH structure was achieved by controlled co-precipitation at pH=9.0 in the presence of papain. Characterization of the MgAl-papain-LDH phase was carried out using X-ray powder diffraction (XRD), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). According to XRD, papain was successfully intercalated. The d-value for the basal spacing of MgAl-papain-LDH was found at ˜5.3 nm. Consequently, original papain (hydrodynamic diameter ˜7.2 nm) attains a compressed conformation during intercalation.Formation of MgAl-papain-LDH was confirmed by elemental analysis and transmission electron microscopy (TEM). Under SEM, MgAl-papain-LDH phases appear as nanothin platelets which are intergrown to flower-like aggregates. Steric size and activity of the enzyme was retained after deintercalation from MgAl-LDH framework, as was evidenced by light scattering and UV/vis measurements. Thus, papain is not denatured during intercalation, and LDH is a suitable host structure which can provide a time-controlled release of the biomolecule.

Intercalation of diclofenac in modified Zn/Al hydrotalcite-like preparation

Science.gov (United States)

Heraldy, E.; Suprihatin, R. W.; Pranoto

2016-02-01

The intercalation of a pharmaceutically active material diclofenac into modified Zn/Al Hydrotalcite-like (Zn/Al HTlc) preparation has been investigated by the coprecipitation and ion exchange method, respectively. The synthetic materials were characterized using X- Ray Diffraction (XRD); Fourier transforms infrared spectroscopy (FTIR); Scanning Electron Microscope (SEM); X-Ray Fluorescence (XRF) and surface area analyzer. The results show that the basal spacing of the product was expanded to 11.03 A for direct synthesis and 10.68 A for indirect synthesis, suggesting that diclofenac anion was intercalated into Zn/Al HTlc and arranged in a tilted bilayer fashion and the specific surface area of material increased after the intercalation of diclofenac.

INTERPRETATION OF POTENTIAL INTERMITTENCE TITRATION TECHNIQUE EXPERIMENTS FOR VARIOUS Li-INTERCALATION ELECTRODES

Directory of Open Access Journals (Sweden)

M.D.Levi

2002-01-01

Full Text Available In this paper we compare two different approaches for the calculation of the enhancement factor Wi, based on its definition as the ratio of the chemical and the component diffusion coefficients for species in mixed-conduction electrodes, originated from the "dilute solution" or "lattice gas" models for the ion system. The former approach is only applicable for small changes of the ion concentration while the latter allows one to consider a broad range of intercalation levels. The component diffusion coefficient of lithium ions has been determined for a series of lithium intercalation anodes and cathodes. A new "enhancement factor" for the ion transport has been defined and its relations to the intercalation capacitance and the intercalation isotherm have been established. A correlation between the dependences of the differential capacitance and the partial ion conductivity on the potential has been observed. It is considered as a prove that the intercalation process is controlled by the availability of sites for Li-ion insertion rather than by the concurrent insertion of the counter-balancing electronic species.

Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

International Nuclear Information System (INIS)

Moradian, Rostam; Behzad, Somayeh; Chegel, Raad

2009-01-01

We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated (6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated (6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

Science.gov (United States)

Moradian, Rostam; Behzad, Somayeh; Chegel, Raad

2009-06-01

We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated ( 6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated ( 6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

Ab initio density functional theory investigation of Li-intercalated silicon carbide nanotube bundles

Energy Technology Data Exchange (ETDEWEB)

Moradian, Rostam [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of); Nano Science and Technology Research Center, Razi University, Kermanshah (Iran, Islamic Republic of); Computational Physical Science Research Laboratory, Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), PO Box 19395-5531, Tehran (Iran, Islamic Republic of)], E-mail: moradian.rostam@gmail.com; Behzad, Somayeh; Chegel, Raad [Physics Department, Faculty of Science, Razi University, Kermanshah (Iran, Islamic Republic of)

2009-06-15

We present the results of ab initio density functional theory calculations on the energetic, and geometric and electronic structure of Li-intercalated (6,6) silicon carbide nanotube (SiCNT) bundles. Our results show that intercalation of lithium leads to the significant changes in the geometrical structure. The most prominent effect of Li intercalation on the electronic band structure is a shift of the Fermi energy which occurs as a result of charge transfer from lithium to the SiCNTs. All the Li-intercalated (6,6) SiCNT bundles are predicted to be metallic representing a substantial change in electronic properties relative to the undoped bundle, which is a wide band gap semiconductor. Both inside of the nanotube and the interstitial space are susceptible for intercalation. The present calculations suggest that the SiCNT bundle is a promising candidate for the anode material in battery applications.

Optical properties of NbCl5 and ZnMg intercalated graphite compounds

International Nuclear Information System (INIS)

Jung, Eilho; Lee, Seokbae; Roh, Seulki; Kang, Jihoon; Park, Tuson; Hwang, Jungseek; Meng, Xiuqing; Tongay, Sefaattin

2014-01-01

We studied NbCl 5 and ZnMg alloy intercalated graphite compounds using an optical spectroscopy technique. These intercalated metallic graphite samples were quite challenging to obtain optical reflectance spectra since they were not flat and quite thin. By using both a new method and an in situ gold evaporation technique we were able to obtain reliable reflectance spectra of our samples in the far and mid infrared range (80–7000 cm −1 ). We extracted the optical constants including the optical conductivity and the dielectric function from the measured reflectance spectra using a Kramers–Kronig analysis. We also extracted the dc conductivity and the plasma frequencies from the optical conductivity and dielectric functions. NbCl 5 intercalated graphite samples show similar optical conductivity spectra as bare highly oriented pyrolytic graphite even though there are some differences in detail. ZnMg intercalated samples show significantly different optical conductivity spectra from the bare graphite. Optical spectroscopy is one of the most reliable experimental techniques to obtain the electronic band structures of materials. The obtained optical conductivities support the recent theoretically calculated electronic band structures of NbCl 5 and ZnMg intercalated graphite compounds. Our results also provide important information of electronic structures and charge carrier properties of these two new intercalated materials for applications. (paper)

Mechanochemical synthesis and intercalation of Ca(II)Fe(III)-layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Ferencz, Zs.; Szabados, M.; Varga, G.; Csendes, Z. [Department of Organic Chemistry, University of Szeged, Dóm tér 8, Szeged H-6720 (Hungary); Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Kukovecz, Á. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE “Lendület” Porous Nanocomposites Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Kónya, Z. [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720 (Hungary); MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, Rerrich Béla tér 1, Szeged H-6720 (Hungary); Carlson, S. [MAX IV Laboratory, Ole Römers väg 1, Lund SE-223 63 (Sweden); Sipos, P. [Materials and Solution Structure Research Group, Institute of Chemistry, University of Szeged, Aradi Vértanúk tere 1, Szeged H-6720 (Hungary); Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720 (Hungary); and others

2016-01-15

A mechanochemical method (grinding the components without added water – dry grinding, followed by further grinding in the presence of minute amount of water or NaOH solution – wet grinding) was used in this work for the preparation and intercalation of CaFe-layered double hydroxides (LDHs). Both the pristine LDHs and the amino acid anion (cystinate and tyrosinate) intercalated varieties were prepared by the two-step grinding procedure in a mixer mill. By systematically changing the conditions of the preparation method, a set of parameters could be determined, which led to the formation of close to phase-pure LDH. The optimisation procedure was also applied for the intercalation processes of the amino acid anions. The resulting materials were structurally characterised by a range of methods (X-ray diffractometry, scanning electron microscopy, energy dispersive analysis, thermogravimetry, X-ray absorption and infra-red spectroscopies). It was proven that this simple mechanochemical procedure was able to produce complex organic–inorganic nanocomposites: LDHs intercalated with amino acid anions. - Graphical abstract: Amino acid anion-Ca(II)Fe(III)-LDHs were successfully prepared by a two-step milling procedure. - Highlights: • Synthesis of pristine and amino acid intercalated CaFe-LDHs by two-step milling. • Identifying the optimum synthesis and intercalation parameters. • Characterisation of the samples with a range of instrumental methods.

Rashba splitting of 100 meV in Au-intercalated graphene on SiC

Energy Technology Data Exchange (ETDEWEB)

Marchenko, D.; Varykhalov, A.; Sánchez-Barriga, J.; Rader, O. [Helmholtz-Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Seyller, Th. [Institut für Physik, Technische Universität Chemnitz, Reichenhainer Strasse 70, 09126 Chemnitz (Germany)

2016-04-25

Intercalation of Au can produce giant Rashba-type spin-orbit splittings in graphene, but this has not yet been achieved on a semiconductor substrate. For graphene/SiC(0001), Au intercalation yields two phases with different doping. We observe a 100 meV Rashba-type spin-orbit splitting at 0.9 eV binding energy in the case of p-type graphene after Au intercalation. We show that this giant splitting is due to hybridization and much more limited in energy and momentum space than for Au-intercalated graphene on Ni.

Structure and thermal decomposition of sulfated β-cyclodextrin intercalated in a layered double hydroxide

International Nuclear Information System (INIS)

Wang Ji; Wei Min; Rao Guoying; Evans, D.G.; Duan Xue

2004-01-01

The sodium salt of hexasulfated β-cyclodextrin has been synthesized and intercalated into a magnesium-aluminum layered double hydroxide by ion exchange. The structure, composition and thermal decomposition behavior of the intercalated material have been studied by variable temperature X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma emission spectroscopy (ICP), and thermal analysis (TG-DTA) and a model for the structure has been proposed. The thermal stability of the intercalated sulfated β-cyclodextrin is significantly enhanced compared with the pure form before intercalation

Structure and thermal decomposition of sulfated β-cyclodextrin intercalated in a layered double hydroxide

Science.gov (United States)

Wang, Ji; Wei, Min; Rao, Guoying; Evans, David G.; Duan, Xue

2004-01-01

The sodium salt of hexasulfated β-cyclodextrin has been synthesized and intercalated into a magnesium-aluminum layered double hydroxide by ion exchange. The structure, composition and thermal decomposition behavior of the intercalated material have been studied by variable temperature X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), inductively coupled plasma emission spectroscopy (ICP), and thermal analysis (TG-DTA) and a model for the structure has been proposed. The thermal stability of the intercalated sulfated β-cyclodextrin is significantly enhanced compared with the pure form before intercalation.

Thermal Stability of Modified i-Motif Oligonucleotides with Naphthalimide Intercalating Nucleic Acids

DEFF Research Database (Denmark)

El-Sayed, Ahmed Ali; Pedersen, Erik B.; Khaireldin, Nahid Y.

2016-01-01

In continuation of our investigation of characteristics and thermodynamic properties of the i-motif 5′-d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine-rich oligonucleotide, this article evaluates the stabilities of i-motif oligonucleotides upon insertion of naphtha......In continuation of our investigation of characteristics and thermodynamic properties of the i-motif 5′-d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine-rich oligonucleotide, this article evaluates the stabilities of i-motif oligonucleotides upon insertion...... of naphthalimide (1H-benzo[de]isoquinoline-1,3(2H)-dione) as the intercalating nucleic acid. The stabilities of i-motif structures with inserted naphthalimide intercalating nucleotides were studied using UV melting temperatures (Tm) and circular dichroism spectra at different pH values and conditions (crowding...

Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review

OpenAIRE

Darija Cör; Željko Knez; Maša Knez Hrnčič

2018-01-01

Ganoderma lucidum (Reishi) is a popular medicinal mushroom and has been used in oriental medicine because of its promoting effects on health and life expectancy. G. lucidum contains various compounds with a high grade of biological activty, which increase the immunity and show antitumour, antimicrobial, anti-inflammatory, antioxidant and acetylcholinesterase inhibitory activity. Several of these substances belong to the triterpenoids and polysaccharides classes. Proteins, lipids, phenols, ste...

Analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates

Energy Technology Data Exchange (ETDEWEB)

Gautier, Romain [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France); Centre Nationale de la Recherche Scientifique (CNRS), Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes (France); Fourre, Yoann; Furet, Eric; Gautier, Regis; Le Fur, Eric [Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS - Ecole Nationale Superieure de Chimie de Rennes (France)

2015-04-15

An approach is presented that enables the analysis and prediction of stacking sequences in intercalated lamellar vanadium phosphates. A comparison of previously reported vanadium phosphates reveals two modes of intercalation: (i) 3d transition metal ions intercalated between VOPO{sub 4} layers and (ii) alkali/alkaline earth metal ions between VOPO{sub 4}.H{sub 2}O layers. Both intercalations were investigated using DFT calculations in order to understand the relative shifts of the vanadium phosphate layers. These calculations in addition to an analysis of the stacking sequences in previously reported materials enable the prediction of the crystal structures of M{sub x}(VOPO{sub 4}).yH{sub 2}O (M = Cs{sup +}, Cd{sup 2+} and Sn{sup 2+}). Experimental realization and structural determination of Cd(VOPO{sub 4}){sub 2}.4H{sub 2}O by single-crystal X-ray diffraction confirmed the predicted stacking sequences. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

International Nuclear Information System (INIS)

Kaassis, Abdessamad Y.A.; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

2016-01-01

The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co 1.2 Zn 3.8 (OH) 8 ](NO 3 ) 2 ·2H 2 O (CoZn-NO 3 ), [Ni 2 Zn 3 (OH) 8 ](NO 3 ) 2 ·2H 2 O (NiZn-NO 3 ) and [Zn 5 (OH) 8 ](NO 3 ) 2 ·2H 2 O (Zn-NO 3 ). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO 3 but when it was reacted with Zn-NO 3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an “X” shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO 3 and Zn-NO 3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO 3 and of Val into CoZn-NO 3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles. - Graphical abstract: Seven new drug intercalates of hydroxy double salts (HDSs) have been prepared and characterised. The intercalation mechanisms have been explored, and the drug release properties of the HDS/drug composites quantified. Display Omitted

Metallization and stiffness of the Li-intercalated MoS{sub 2} bilayer

Energy Technology Data Exchange (ETDEWEB)

Petrova, N.V. [Institute of Physics of National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine); Yakovkin, I.N., E-mail: yakov@iop.kiev.ua [Institute of Physics of National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03028 (Ukraine); Zeze, D.A. [School of Engineering & Computing Sciences, Durham University, Durham DH1 3LE (United Kingdom)

2015-10-30

Graphical abstract: The band structures, DOS, and Fermi surfaces for the MoS{sub 2} bilayer with adsorbed (a, c, e) and intercalated (b, d, f) Li (1 × 1) layer. - Highlights: • Adsorbed or intercalated Li monolayer makes the MoS{sub 2} surface metallic. • Increasing density of adsorbed Li leads to the nonmetal-to-metal transition in the layer. • Lithium inserted into MoS{sub 2} bilayers increases the interlayer interaction. - Abstract: Performed density-functional theory (DFT) calculations have shown that the Li adsorption on the MoS{sub 2} (0 0 0 1) surface, as well as Li intercalation into the space between MoS{sub 2} layers, transforms the semiconductor band structure of MoS{sub 2} into metallic. For the (√3 × √3) – R30° Li layer, the band structures of the MoS{sub 2} bilayer with adsorbed and intercalated Li are very similar, while for higher Li concentrations, the character of metallization for the adsorbed layer substantially differs from that of the MoS{sub 2}–Li–MoS{sub 2} layered system. In particular, for the adsorbed (1 × 1) Li monolayer, the increased density of the layer leads to the nonmetal-to-metal transition, which is evident from the appearance of the band crossing E{sub F} with an upward dispersion, pertinent to simple metals. It has been demonstrated that intercalated Li substantially increases the interlayer interaction in MoS{sub 2}. Specifically, the estimated 0.12 eV energy of the interlayer interaction in the MoS{sub 2} bilayer increases to 0.60 eV. This result is also consistent with results of earlier DFT calculations and available experimental results for alkali-intercalated graphene layers, which have demonstrated a substantial increase in the stiffness due to intercalation of alkalis.

Quasi-Free-Standing Graphene Monolayer on a Ni Crystal through Spontaneous Na Intercalation

Directory of Open Access Journals (Sweden)

Young S. Park

2014-07-01

Full Text Available Graphene on metal substrates often shows different electronic properties from isolated graphene because of graphene-substrate interactions. One needs to remove the metals with acids and then to transfer graphene to weakly interacting substrates to recover electrical properties inherent in graphene. This process is not easy and besides causes undesirable tears, defects, and impurities in graphene. Here, we report a method to recover the electronic structure of graphene from a strongly interacting Ni substrate by spontaneous Na intercalation. In order to characterize the intercalation process, the density-functional-theory calculations and angle-resolved photoemission-spectroscopy (ARPES and scanning-tunneling-microscopy (STM measurements are carried out. From the density-functional-theory calculations, Na atoms energetically prefer interface intercalation to surface adsorption for the graphene/Ni(111 surface. Unlike most intercalants, Na atoms intercalate spontaneously at room temperature due to a tiny diffusion barrier, which is consistent with our temperature-dependent ARPES and core-level photoemission spectroscopy, and with our submonolayer ARPES and STM results at room temperature. As a result of the spontaneous intercalation, the electronic structure of graphene is almost recovered, as confirmed by the Dirac cone with a negligible band gap in ARPES and the sixfold symmetry in STM.

A rechargeable iodine-carbon battery that exploits ion intercalation and iodine redox chemistry.

Science.gov (United States)

Lu, Ke; Hu, Ziyu; Ma, Jizhen; Ma, Houyi; Dai, Liming; Zhang, Jintao

2017-09-13

Graphitic carbons have been used as conductive supports for developing rechargeable batteries. However, the classic ion intercalation in graphitic carbon has yet to be coupled with extrinsic redox reactions to develop rechargeable batteries. Herein, we demonstrate the preparation of a free-standing, flexible nitrogen and phosphorus co-doped hierarchically porous graphitic carbon for iodine loading by pyrolysis of polyaniline coated cellulose wiper. We find that heteroatoms could provide additional defect sites for encapsulating iodine while the porous carbon skeleton facilitates redox reactions of iodine and ion intercalation. The combination of ion intercalation with redox reactions of iodine allows for developing rechargeable iodine-carbon batteries free from the unsafe lithium/sodium metals, and hence eliminates the long-standing safety issue. The unique architecture of the hierarchically porous graphitic carbon with heteroatom doping not only provides suitable spaces for both iodine encapsulation and cation intercalation but also generates efficient electronic and ionic transport pathways, thus leading to enhanced performance.Carbon-based electrodes able to intercalate Li + and Na + ions have been exploited for high performing energy storage devices. Here, the authors combine the ion intercalation properties of porous graphitic carbons with the redox chemistry of iodine to produce iodine-carbon batteries with high reversible capacities.

Optical determination of the electronic coupling and intercalation geometry of thiazole orange homodimer in DNA

Science.gov (United States)

Cunningham, Paul D.; Bricker, William P.; Díaz, Sebastián A.; Medintz, Igor L.; Bathe, Mark; Melinger, Joseph S.

2017-08-01

Sequence-selective bis-intercalating dyes exhibit large increases in fluorescence in the presence of specific DNA sequences. This property makes this class of fluorophore of particular importance to biosensing and super-resolution imaging. Here we report ultrafast transient anisotropy measurements of resonance energy transfer (RET) between thiazole orange (TO) molecules in a complex formed between the homodimer TOTO and double-stranded (ds) DNA. Biexponential homo-RET dynamics suggest two subpopulations within the ensemble: 80% intercalated and 20% non-intercalated. Based on the application of the transition density cube method to describe the electronic coupling and Monte Carlo simulations of the TOTO/dsDNA geometry, the dihedral angle between intercalated TO molecules is estimated to be 81° ± 5°, corresponding to a coupling strength of 45 ± 22 cm-1. Dye intercalation with this geometry is found to occur independently of the underlying DNA sequence, despite the known preference of TOTO for the nucleobase sequence CTAG. The non-intercalated subpopulation is inferred to have a mean inter-dye separation distance of 19 Å, corresponding to coupling strengths between 0 and 25 cm-1. This information is important to enable the rational design of energy transfer systems that utilize TOTO as a relay dye. The approach used here is generally applicable to determining the electronic coupling strength and intercalation configuration of other dimeric bis-intercalators.

An in situ Raman study of the intercalation of supercapacitor-type electrolyte into microcrystalline graphite

International Nuclear Information System (INIS)

Hardwick, Laurence J.; Hahn, Matthias; Ruch, Patrick; Holzapfel, Michael; Scheifele, Werner; Buqa, Hilmi; Krumeich, Frank; Novak, Petr; Koetz, Ruediger

2006-01-01

An initial Raman study on the effects of intercalation for aprotic electrolyte-based electrochemical double-layer capacitors (EDLCs) is reported. In situ Raman microscopy is employed in the study of the electrochemical intercalation of tetraethylammonium (Et 4 N + ) and tetrafluoroborate (BF 4 - ) into and out of microcrystalline graphite. During cyclic voltammetry experiments, the insertion of Et 4 N + into graphite for the negative electrode occurs at an onset potential of +1.0 V versus Li/Li + . For the positive electrode, BF 4 - was shown to intercalate above +4.3 V versus Li/Li + . The characteristic G-band doublet peak (E 2g2 (i) (1578 cm -1 ) and E 2g2 (b) (1600 cm -1 )) showed that various staged compounds were formed in both cases and the return of the single G-band (1578 cm -1 ) demonstrates that intercalation was fully reversible. The disappearance of the D-band (1329 cm -1 ) in intercalated graphite is also noted and when the intercalant is removed a more intense D-band reappears, indicating possible lattice damage. For cation intercalation, such irreversible changes of the graphite structure are confirmed by scanning electron microscopy (SEM)

Evaluation of the purified fraction of Wilbrandia (c. f. verticillata for antitumour activity

Directory of Open Access Journals (Sweden)

V. S. N. Rao

1991-01-01

Full Text Available Cucurbatacins are known to produce cytotoxic and anticancer activities. Two novel norcucurbitacin glucosides (Wvl and Wv2 have recently been isolated from a purified fraction obtained from the rhizome of Wilbrandia verticillata. The present study evaluates the cytotoxic and anti-tumour activities of the norcucurbitacins. We have found a regular cytotoxicity in KB cells (Cy50 = 12µg/ml as well as a significant inhibition in the Walker 256 carcinosarcoma growth (approximately 75%.

clay nanocomposite by solution intercalation technique

Indian Academy of Sciences (India)

Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS.

Severe glandular tularemia in a patient treated with anti-tumour necrosis factor for psoriatic arthritis

Directory of Open Access Journals (Sweden)

Ruxandra Calin

2017-07-01

Full Text Available A case of severe glandular tularemia in a patient receiving anti-tumour necrosis factor (TNF therapy is reported here. The patient required prolonged treatment with doxycycline–ciprofloxacin due to early relapse after ciprofloxacin was stopped. Tularemia may have a more severe course in patients receiving anti-TNF. This may thus be an indication for more aggressive treatment.

Modulation of actin dynamics as potential macrophage subtype-targeting anti-tumour strategy.

Science.gov (United States)

Pergola, Carlo; Schubert, Katrin; Pace, Simona; Ziereisen, Jana; Nikels, Felix; Scherer, Olga; Hüttel, Stephan; Zahler, Stefan; Vollmar, Angelika M; Weinigel, Christina; Rummler, Silke; Müller, Rolf; Raasch, Martin; Mosig, Alexander; Koeberle, Andreas; Werz, Oliver

2017-01-30

Tumour-associated macrophages mainly comprise immunosuppressive M2 phenotypes that promote tumour progression besides anti-tumoural M1 subsets. Selective depletion or reprogramming of M2 may represent an innovative anti-cancer strategy. The actin cytoskeleton is central for cellular homeostasis and is targeted for anti-cancer chemotherapy. Here, we show that targeting G-actin nucleation using chondramide A (ChA) predominantly depletes human M2 while promoting the tumour-suppressive M1 phenotype. ChA reduced the viability of M2, with minor effects on M1, but increased tumour necrosis factor (TNF)α release from M1. Interestingly, ChA caused rapid disruption of dynamic F-actin filaments and polymerization of G-actin, followed by reduction of cell size, binucleation and cell division, without cellular collapse. In M1, but not in M2, ChA caused marked activation of SAPK/JNK and NFκB, with slight or no effects on Akt, STAT-1/-3, ERK-1/2, and p38 MAPK, seemingly accounting for the better survival of M1 and TNFα secretion. In a microfluidically-supported human tumour biochip model, circulating ChA-treated M1 markedly reduced tumour cell viability through enhanced release of TNFα. Together, ChA may cause an anti-tumoural microenvironment by depletion of M2 and activation of M1, suggesting induction of G-actin nucleation as potential strategy to target tumour-associated macrophages in addition to neoplastic cells.

Chitosan derivatives with antimicrobial, antitumour and antioxidant activities--a review.

Science.gov (United States)

Jarmila, Vinsová; Vavríková, Eva

2011-01-01

Chitosan is a linear polysaccharide with a good biodegradability, biocompatibility, and no toxicity, which provide it with huge potential for future development. The chitosan molecule appears to be a suitable polymeric complex for many biomedical applications. This review gathers current findings on the antibacterial, antifungal, antitumour and antioxidant activities of chitosan derivatives and concurs with our previous review presenting data collected up to 2008. Antibacterial activity is based on molecular weight, the degree of deacetylation, the type of substitutents, which can be cationic or easily form cations, and the type of bacterium. In general, high molecular weight chitosan cannot pass through cell membranes and forms a film that protects cells against nutrient transport through the microbial cell membrane. Low molecular weight chitosan derivatives are water soluble and can better incorporate the active molecule into the cell. Gram-negative bacteria, often represented by Escherichia coli, have an anionic bacterial surface on which cationic chitosan derivatives interact electrostatically. Thus, many chitosan conjugates have cationic components such as ammonium, pyridinium or piperazinium substituents introduced into their molecules to increase their positive charge. Gram-positive bacteria like Staphylococcus aureus are inhibited by the binding of lower molecular weight chitosan derivatives to DNA or RNA. Chitosan nanoparticles exhibit an increase in loading capacity and efficacy. Antitumour active compounds such as doxorubicin, paclitaxel, docetaxel and norcantharidin are used as drug carriers. It is evident that chitosan, with its low molecular weight, is a useful carrier for molecular drugs requiring targeted delivery. The antioxidant scavenging activity of chitosan has been established by the strong hydrogen-donating ability of chitosan. The low molecular weight and greater degree of quarternization have a positive influence on the antioxidant activity

Potassium-intercalated H2Pc films : Alkali-induced electronic and geometrical modifications

NARCIS (Netherlands)

Nilson, K.; Ahlund, J.; Shariati, M. -N.; Schiessling, J.; Palmgren, P.; Brena, B.; Gothelid, E.; Hennies, F.; Huismans, Y.; Evangelista, F.; Rudolf, P.; Gothelid, M.; Martensson, N.; Puglia, C.; Åhlund, J.; Göthelid, E.; Göthelid, M.; Mårtensson, N.

2012-01-01

X-ray spectroscopy studies of potassium intercalated metal-free phthalocyanine multilayers adsorbed on Al(110) have been undertaken. Photoelectron spectroscopy measurements show the presence of several charge states of the molecules upon K intercalation, due to a charge transfer from the alkali. In

Facile synthesis of deoxycholate intercalated layered double hydroxide nanohybrids via a coassembly process

International Nuclear Information System (INIS)

Wu, Xiaowen; Wang, Shuang; Du, Na; Zhang, Renjie; Hou, Wanguo

2013-01-01

In this paper, we describe a synthesis strategy of deoxycholate (DC) intercalated layered double hydroxide (LDH) nanohybrids via a coassembly method at room temperature. For this strategy, LDH particles were delaminated to well-dispersed 2D nanosheets in formamide, and the resulting LDH nanosheets were then coassembled with DC anions into the DC intercalated LDH (DC-LDH) nanohybrids. The so-synthesized nanohybrids were characterized by XRD, TEM, FT-IR, elemental analyses and TG-DSC. It was found that the loading amount of DC in the nanohybrids could be easily controlled by changing the ratio of DC to LDH. In addition, the nanohybrids have similar characteristics with the DC-LDH nanohybrids synthesized by the hydrothermal method, including their DC loading, crystal structure, morphology and thermal gravimetric behavior. However, this strategy exhibited the advantages of short reaction time and mild experimental conditions compared with the hydrothermal method. - Graphical abstract: Deoxycholate intercalated layered double hydroxide nanohybrids were successfully synthesized via a coassembly strategy. In this strategy, the interlayer spaces of LDHs can be efficiently used for the intercalation of guest species. - Highlights: • Deoxycholate intercalated layered double hydroxide nanohybrids were synthesized via a coassembly strategy. • This strategy exhibited the advantages of short time and mild conditions. • This strategy can enable organic species to be readily intercalated into the LDH galleries

New insights into the intercalation chemistry of Al(OH)3.

Science.gov (United States)

Williams, Gareth R; Moorhouse, Saul J; Prior, Timothy J; Fogg, Andrew M; Rees, Nicholas H; O'Hare, Dermot

2011-06-14

This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

Energy Technology Data Exchange (ETDEWEB)

Kaassis, Abdessamad Y.A. [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom); Xu, Si-Min; Guan, Shanyue; Evans, David G. [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wei, Min, E-mail: weimin@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Williams, Gareth R., E-mail: g.williams@ucl.ac.uk [UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)

2016-06-15

The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co{sub 1.2}Zn{sub 3.8}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (CoZn-NO{sub 3}), [Ni{sub 2}Zn{sub 3}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (NiZn-NO{sub 3}) and [Zn{sub 5}(OH){sub 8}](NO{sub 3}){sub 2}·2H{sub 2}O (Zn-NO{sub 3}). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO{sub 3} but when it was reacted with Zn-NO{sub 3} the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an “X” shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO{sub 3} and Zn-NO{sub 3} is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO{sub 3} and of Val into CoZn-NO{sub 3} are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles. - Graphical abstract: Seven new drug intercalates of hydroxy double salts (HDSs) have been prepared and characterised. The intercalation mechanisms have been explored, and the drug release properties of the HDS/drug composites quantified. Display Omitted.

Capacitive Sensing of Intercalated H2O Molecules Using Graphene.

Science.gov (United States)

Olson, Eric J; Ma, Rui; Sun, Tao; Ebrish, Mona A; Haratipour, Nazila; Min, Kyoungmin; Aluru, Narayana R; Koester, Steven J

2015-11-25

Understanding the interactions of ambient molecules with graphene and adjacent dielectrics is of fundamental importance for a range of graphene-based devices, particularly sensors, where such interactions could influence the operation of the device. It is well-known that water can be trapped underneath graphene and its host substrate; however, the electrical effect of water beneath graphene and the dynamics of how the interfacial water changes with different ambient conditions has not been quantified. Here, using a metal-oxide-graphene variable-capacitor (varactor) structure, we show that graphene can be used to capacitively sense the intercalation of water between graphene and HfO2 and that this process is reversible on a fast time scale. Atomic force microscopy is used to confirm the intercalation and quantify the displacement of graphene as a function of humidity. Density functional theory simulations are used to quantify the displacement of graphene induced by intercalated water and also explain the observed Dirac point shifts as being due to the combined effect of water and oxygen on the carrier concentration in the graphene. Finally, molecular dynamics simulations indicate that a likely mechanism for the intercalation involves adsorption and lateral diffusion of water molecules beneath the graphene.

Single nucleotide polymorphism discrimination with and without an ethidium bromide intercalator

International Nuclear Information System (INIS)

Fenati, Renzo A.; Connolly, Ashley R.; Ellis, Amanda V.

2017-01-01

Single nucleotide polymorphism (SNP) genotyping is an important aspect in understanding genetic variations. Here, we discriminate SNPs using toe-hold mediated displacement reactions. The biological target is an 80 nucleotide long double-stranded–DNA from the mtDNA HV1 region, associated with maternal ancestry. This target has been specially designed with a pendant toehold and a cationic fluorophore, ATTO 647N, as a reporter, produced in a polymerase chain reaction. Rates of reaction for the toehold-polymerase chain reaction products (TPPs) with their corresponding complementary displacing sequences, labelled with a Black Hole Quencher 1, followed the order TPP–Cytosine > TPP–Thymine > TPP–Adenine ≥ TPP–Guanine. Non-complementary rates were the slowest with mismatches involving cytosine. These reactions, operating in a static/or contact mode, gave averaged readouts between SNPs within 15 min (with 80–90% quenching), compared to 25–30 min in previous studies involving fluorescence resonance energy transfer. Addition of an intercalating agent, ethidium bromide, retarded the rate of reaction in which cytosine was involved, presumably through stabilization of the base pairing, which resulted in markedly improved discrimination of cytosine containing SNPs. - Highlights: • Fluorophores and DNA intercalators effect the rate of toehold-mediated strand displacement. • Ethidium bromide had a destabilizing effect on mismatches that contained cytosine. • A cationic fluorophore and Black Hole Quencher 1 strand displacement system was 2–3 times faster than a FRET system. • This enabled SNP detection using toehold-mediated strand displacement in 15 min.

Single nucleotide polymorphism discrimination with and without an ethidium bromide intercalator

Energy Technology Data Exchange (ETDEWEB)

Fenati, Renzo A.; Connolly, Ashley R. [Flinders Centre for Nanoscale Science and Technology, Flinders University, Sturt Road, Bedford Park, Adelaide, South Australia 5042 (Australia); Ellis, Amanda V., E-mail: amanda.ellis@flinders.edu.au [Flinders Centre for Nanoscale Science and Technology, Flinders University, Sturt Road, Bedford Park, Adelaide, South Australia 5042 (Australia); Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, VIC 3010 (Australia)

2017-02-15

Single nucleotide polymorphism (SNP) genotyping is an important aspect in understanding genetic variations. Here, we discriminate SNPs using toe-hold mediated displacement reactions. The biological target is an 80 nucleotide long double-stranded–DNA from the mtDNA HV1 region, associated with maternal ancestry. This target has been specially designed with a pendant toehold and a cationic fluorophore, ATTO 647N, as a reporter, produced in a polymerase chain reaction. Rates of reaction for the toehold-polymerase chain reaction products (TPPs) with their corresponding complementary displacing sequences, labelled with a Black Hole Quencher 1, followed the order TPP–Cytosine > TPP–Thymine > TPP–Adenine ≥ TPP–Guanine. Non-complementary rates were the slowest with mismatches involving cytosine. These reactions, operating in a static/or contact mode, gave averaged readouts between SNPs within 15 min (with 80–90% quenching), compared to 25–30 min in previous studies involving fluorescence resonance energy transfer. Addition of an intercalating agent, ethidium bromide, retarded the rate of reaction in which cytosine was involved, presumably through stabilization of the base pairing, which resulted in markedly improved discrimination of cytosine containing SNPs. - Highlights: • Fluorophores and DNA intercalators effect the rate of toehold-mediated strand displacement. • Ethidium bromide had a destabilizing effect on mismatches that contained cytosine. • A cationic fluorophore and Black Hole Quencher 1 strand displacement system was 2–3 times faster than a FRET system. • This enabled SNP detection using toehold-mediated strand displacement in 15 min.

Effect of friction on oxidative graphite intercalation and high-quality graphene formation.

Science.gov (United States)

Seiler, Steffen; Halbig, Christian E; Grote, Fabian; Rietsch, Philipp; Börrnert, Felix; Kaiser, Ute; Meyer, Bernd; Eigler, Siegfried

2018-02-26

Oxidative wet-chemical delamination of graphene from graphite is expected to become a scalable production method. However, the formation process of the intermediate stage-1 graphite sulfate by sulfuric acid intercalation and its subsequent oxidation are poorly understood and lattice defect formation must be avoided. Here, we demonstrate film formation of micrometer-sized graphene flakes with lattice defects down to 0.02% and visualize the carbon lattice by transmission electron microscopy at atomic resolution. Interestingly, we find that only well-ordered, highly crystalline graphite delaminates into oxo-functionalized graphene, whereas other graphite grades do not form a proper stage-1 intercalate and revert back to graphite upon hydrolysis. Ab initio molecular dynamics simulations show that ideal stacking and electronic oxidation of the graphite layers significantly reduce the friction of the moving sulfuric acid molecules, thereby facilitating intercalation. Furthermore, the evaluation of the stability of oxo-species in graphite sulfate supports an oxidation mechanism that obviates intercalation of the oxidant.

Acrylate intercalation and in situ polymerization in iron-, cobalt-, or manganese-substituted nickel hydroxides.

Science.gov (United States)

Vaysse, C; Guerlou-Demourgues, L; Duguet, E; Delmas, C

2003-07-28

A chimie douce route based on successive redox and exchange reactions has allowed us to prepare new hybrid organic-inorganic materials, composed of polyacrylate macromolecules intercalated into layered double hydroxides (LDHs), deriving from Ni(OH)(2). Monomer intercalation and in situ polymerization mechanisms have appeared to be strongly dependent upon the nature of the substituting cation in the slabs. In the case of iron-based LDHs, a phase containing acrylate monomeric intercalates has been isolated and identified by X-ray diffraction and infrared spectroscopy. Second, interslab free-radical polymerization of acrylate anions has been successfully initiated using potassium persulfate. In cobalt- or manganese-based LDHs, one-step polymerization has been observed, leading directly to a material containing polyacrylate intercalate.

Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

Science.gov (United States)

Tarasov, Konstantin A; O'Hare, Dermot; Isupov, Vitaly P

2003-03-24

The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3).

Intercalation behavior of barium phenylphosphonate

Czech Academy of Sciences Publication Activity Database

Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

2010-01-01

Roč. 71, č. 4 (2010), s. 530-533 ISSN 0022-3697. [15th International Symposium on Intercalation Compounds. Beijing, 11.05.2009-15.05.2009] R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : inorganic compounds * organic compounds * X-ray diffraction Subject RIV: CA - Inorganic Chemistry Impact factor: 1.384, year: 2010

Prophage induction and mutagenicity of a series of anti-tumour platinum(II) and platinum(IV) co-ordination complexes

NARCIS (Netherlands)

Mattern, I.E.; Cocchiarella, L.; Kralingen, C.G. van; Lohman, P.H.M.

1982-01-01

Eleven platinum compounds with nitrogen donor ligands, previously tested for anti-tumour activity were studied for induction of prophage lambda and for mutagenicity in the Ames assay, with various strains of Salmonella. The compounds included cis and trans isomers of Pt(II) and Pt(IV) complexes and

Experiences and needs for work participation in employees with rheumatoid arthritis treated with anti-tumour necrosis factor therapy

NARCIS (Netherlands)

van der Meer, Marrit; Hoving, Jan L.; Vermeulen, Marjolein I. M.; Herenius, Marieke M. J.; Tak, Paul P.; Sluiter, Judith K.; Frings-Dresen, Monique H. W.

2011-01-01

To investigate the experiences and needs with respect to work participation of employees with rheumatoid arthritis (RA) treated with anti-tumour necrosis factor (TNF) therapy. Face-to-face interviews in 14 employees with RA on anti-TNF therapy focused on experiences, offered support and needs with

Thermal analysis and infrared emission spectroscopic study of halloysite-potassium acetate intercalation compound

Energy Technology Data Exchange (ETDEWEB)

Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Liu, Qinfu [School of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083 China (China); Yang, Jing [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zhang, Jinshan [School of Mining Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Frost, Ray L., E-mail: r.frost@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

2010-11-20

The thermal decomposition of halloysite-potassium acetate intercalation compound was investigated by thermogravimetric analysis and infrared emission spectroscopy. The X-ray diffraction patterns indicated that intercalation of potassium acetate into halloysite caused an increase of the basal spacing from 1.00 to 1.41 nm. The thermogravimetry results show that the mass losses of intercalation the compound occur in main three main steps, which correspond to (a) the loss of adsorbed water, (b) the loss of coordination water and (c) the loss of potassium acetate and dehydroxylation. The temperature of dehydroxylation and dehydration of halloysite is decreased about 100 {sup o}C. The infrared emission spectra clearly show the decomposition and dehydroxylation of the halloysite intercalation compound when the temperature is raised. The dehydration of the intercalation compound is followed by the loss of intensity of the stretching vibration bands at region 3600-3200 cm{sup -1}. Dehydroxylation is followed by the decrease in intensity in the bands between 3695 and 3620 cm{sup -1}. Dehydration was completed by 300 {sup o}C and partial dehydroxylation by 350 {sup o}C. The inner hydroxyl group remained until around 500 {sup o}C.

Bromine intercalated graphite for lightweight composite conductors

KAUST Repository

Amassian, Aram; Patole, Archana

2017-01-01

A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a

Preparation and properties of Mg/Al layered double hydroxide-oleate and -stearate intercalation compounds

International Nuclear Information System (INIS)

Inomata, Kazuya; Ogawa, Makoto

2006-01-01

Mg/Al layered double hydroxide-oleate and -stearate intercalation compounds were successfully synthesized by the reconstruction method under hydrothermal conditions from calcined hydrotalcite. The intercalation compounds were characterized by the high structural regularity as evidenced by the sharp and intense X-ray diffraction peaks. The oleate intercalated layered double hydroxide exhibits unique physicochemical properties such as a reversible thermoresponsive change in the basal spacing and swelling in organic solvents such as n-alkanes. (author)

High voltage and high specific capacity dual intercalating electrode Li-ion batteries

Science.gov (United States)

West, William C. (Inventor); Blanco, Mario (Inventor)

2010-01-01

The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

Preparation of Fe-intercalated Graphite Based on Coal Tailings, Dimensional Structure

Directory of Open Access Journals (Sweden)

Irfan Gustian

2015-12-01

Full Text Available Intercalated graphite from coal tailings have been modified through the intercalation of iron. Coal tailings which is a byproduct of the destruction process and flakes washing results from mining coal. Intercalation of iron goal is to improve the physical properties of graphite and modifying sizes of crystal lattice structure with thermal method. Modification process begins with the carbonization of coal tailings at 500ºC and activated with phosphoric acid. Activation process has done by pyrolysis at 700ºC. The results of pyrolysis was soaked in mineral oil for 24 hours, then pyrolysis again with variations in temperature 800°C and 900ºC for 1 hour and subsequent intercalation iron at 1% and 2%. Material before activated, after activated, and the results of pyrolysis still indicates order nano: 29, 25 and 36 nm respectively. X-ray diffraction characterization results indicate that change in the structure, the sizes crystal lattice structure of the material The greater the concentration of iron was added, the resulting peak at 2θ = 33 and 35 also will be more sharply. The results of SEM showed different morphologies from each treatment.

Single-layer dispersions of transition metal dichalcogenides in the synthesis of intercalation compounds

International Nuclear Information System (INIS)

Golub, Alexander S; Zubavichus, Yan V; Slovokhotov, Yurii L; Novikov, Yurii N

2003-01-01

Chemical methods for the exfoliation of transition metal dichalcogenides in a liquid medium to give single-layer dispersions containing quasi-two-dimensional layers of these compounds are surveyed. Data on the structure of dispersions and their use in the synthesis of various types of heterolayered intercalation compounds are discussed and described systematically. Structural features, the electronic structure and the physicochemical properties of the resulting intercalation compounds are considered. The potential of this method of synthesis is compared with that of traditional solid-state methods for the intercalation of layered crystals.

Mycelium cultivation, chemical composition and antitumour activity of a Tolypocladium sp. fungus isolated from wild Cordyceps sinensis.

Science.gov (United States)

Leung, P H; Zhang, Q X; Wu, J Y

2006-08-01

To examine and illustrate the morphological characteristics and growth kinetics of Cs-HK1, a Tolypocladium fungus, isolated from wild Cordyceps sinensis in solid and liquid cultures, and the major chemical constituents and antitumour effects of Cs-HK1 mycelium. The Cs-HK1 fungus was isolated from the fruiting body of a wild C. sinensis and identified as a Tolypocladium sp. fungus. It grew rapidly at 22-25 degrees C on a liquid medium containing glucose, yeast extract, peptone and major inorganic salts, with a specific growth rate of 1.1 day(-1), reaching a cell density of 23.0 g dw l(-1) in 7-9 days. Exopolysaccharides accumulated in the liquid culture to about 0.3 g l(-1) glucose equivalent. In comparison with natural C. sinensis, the fungal mycelium had similar contents of protein (11.7-microg) and carbohydrate (654.6-microg) but much higher contents of polysaccharide (244.2 mg vs 129.5 mg), adenosine (1116.8-microg vs 264.6 microg) and cordycepin (65.7 microg vs 20.8 microg) (per gram dry weight). Cyclosporin A, an antibiotic commonly produced by Tolypocladium sp., was also detected from the mycelium extract. The hot water extract of mycelium showed low cytotoxic effect on B16 melanoma cells in culture (about 25% inhibition) but significant antitumour effect in animal tests, causing 50% inhibition of B16 cell-induced tumour growth in mice. The Tolypocladium sp. fungus, Cs-HK1, can be easily cultivated by liquid fermentation. The mycelium biomass contained the major bioactive compounds of C. sinensis, and the mycelium extract had significant antitumour activity. The Cs-HK1 fungus may be a new and promising medicinal fungus and an effective and economical substitute of the wild C. sinensis for health care.

Induced magnetism in transition metal intercalated graphitic systems

KAUST Repository

Kaloni, Thaneshwor P.; Schwingenschlö gl, Udo; Upadhyay Kahaly, M.

2011-01-01

We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

Induced magnetism in transition metal intercalated graphitic systems

KAUST Repository

Kaloni, Thaneshwor P.

2011-10-26

We investigate the structure, chemical bonding, electronic properties, and magnetic behavior of a three-dimensional graphitic network in aba and aaa stacking with intercalated transition metal atoms (Mn, Fe, Co, Ni, and Cu). Using density functional theory, we find induced spin-polarization of the C atoms both when the graphene sheets are aba stacked (forming graphite) and aaa stacked (resembling bi-layer graphene). The magnetic moment induced by Mn, Fe, and Co turns out to vary from 1.38 μB to 4.10 μB, whereas intercalation of Ni and Cu does not lead to a magnetic state. The selective induction of spin-polarization can be utilized in spintronic and nanoelectronic applications.

Severe glandular tularemia in a patient treated with anti-tumour necrosis factor for psoriatic arthritis.

Science.gov (United States)

Calin, Ruxandra; Caumes, Eric; Reibel, Florence; Ali Mohamed, Anzime; Brossier, Florence; Foltz, Violaine; Boussouar, Samia; Fautrel, Bruno; Maurin, Max; Katlama, Christine; Pourcher, Valérie

2017-07-01

A case of severe glandular tularemia in a patient receiving anti-tumour necrosis factor (TNF) therapy is reported here. The patient required prolonged treatment with doxycycline-ciprofloxacin due to early relapse after ciprofloxacin was stopped. Tularemia may have a more severe course in patients receiving anti-TNF. This may thus be an indication for more aggressive treatment. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Intercalation behavior of amino acids into Zn-Al-layered double hydroxide by calcination-rehydration reaction

International Nuclear Information System (INIS)

Aisawa, Sumio; Kudo, Hiroko; Hoshi, Tomomi; Takahashi, Satoshi; Hirahara, Hidetoshi; Umetsu, Yoshio; Narita, Eiichi

2004-01-01

The intercalation of amino acids for the Zn-Al-layered double hydroxide (LDH) has been investigated by the calcination-rehydration reaction at 298K using mainly phenylalanine (Phe) as a guest amino acid. The Zn-Al oxide precursor prepared by the calcination of Zn-Al-carbonated LDH at 773K for 2h was used as the host material. The amount of Phe intercalated by the rehydration was remarkably influenced by the initial solution pH and reached ca. 2.7 times for anion exchange capacity (AEC) of the LDH at neutral and weak alkaline solutions, suggesting that Phe was intercalated as amphoteric ion form into the LDH interlayer. As Phe is intercalated for the LDH as monovalent anion in alkaline solution, the amount of Phe intercalated at pH 10.5 corresponded with AEC of the LDH. The solid products were found to have the expanded LDH structure, which confirmed that Phe was intercalated into the LDH interlayer as amphoteric ion or anion form. The basal spacing, d 003 , of the Phe/LDH was 1.58nm at pH 7.0 and 0.80nm at pH 10.5; two kinds of expansion suggested for Phe in the interlayer space as vertical (pH 7.0) and horizontal (pH 10.5) orientations. The intercalation behavior of various amino acids for the LDH was also found to be greatly influenced by the feature of the amino acid side-chain, namely, its carbon-chain length, structure and physicochemical property. In particular, α-amino acids possessing a hydrophobic or negative-charged side-chain were preferentially intercalated for the LDH

Structural properties and magnetic susceptibility of iron-intercalated titanium ditelluride

International Nuclear Information System (INIS)

Pleshchev, V.G.; Titov, A.N.; Titova, S.G.; Kuranov, A.V.

1997-01-01

Structural peculiarities and magnetic susceptibility of titanium ditelluride, intercalated by iron, are studied. It is established that the basic motive of crystal structure by intercalation is preserved and the iron atoms are locates in the van der Waals gaps in positions with octahedral coordination. It is shown that the magnetic susceptibility of the Fe 0.25 TiT 2 sample increases approximately by 20 times. The magnetic susceptibility for the Fe 0.33 TiTe 2 samples becomes even much higher

Probing the role of intercalating protein sidechains for kink formation in DNA.

Directory of Open Access Journals (Sweden)

Achim Sandmann

Full Text Available Protein binding can induce DNA kinks, which are for example important to enhance the specificity of the interaction and to facilitate the assembly of multi protein complexes. The respective proteins frequently exhibit amino acid sidechains that intercalate between the DNA base steps at the site of the kink. However, on a molecular level there is only little information available about the role of individual sidechains for kink formation. To unravel structural principles of protein-induced DNA kinking we have performed molecular dynamics (MD simulations of five complexes that varied in their architecture, function, and identity of intercalated residues. Simulations were performed for the DNA complexes of wildtype proteins (Sac7d, Sox-4, CcpA, TFAM, TBP and for mutants, in which the intercalating residues were individually or combined replaced by alanine. The work revealed that for systems with multiple intercalated residues, not all of them are necessarily required for kink formation. In some complexes (Sox-4, TBP, one of the residues proved to be essential for kink formation, whereas the second residue has only a very small effect on the magnitude of the kink. In other systems (e.g. Sac7d each of the intercalated residues proved to be individually capable of conferring a strong kink suggesting a partially redundant role of the intercalating residues. Mutation of the key residues responsible for kinking either resulted in stable complexes with reduced kink angles or caused conformational instability as evidenced by a shift of the kink to an adjacent base step. Thus, MD simulations can help to identify the role of individual inserted residues for kinking, which is not readily apparent from an inspection of the static structures. This information might be helpful for understanding protein-DNA interactions in more detail and for designing proteins with altered DNA binding properties in the future.

Hydroxy double salts loaded with bioactive ions: Synthesis, intercalation mechanisms, and functional performance

Science.gov (United States)

Y. A. Kaassis, Abdessamad; Xu, Si-Min; Guan, Shanyue; Evans, David G.; Wei, Min; Williams, Gareth R.

2016-06-01

The intercalation of the anions of diclofenac (Dic), naproxen (Nap), and valproic acid (Val) into three hydroxy double salts (HDSs) has been explored in this work. Experiments were performed with [Co1.2Zn3.8(OH)8](NO3)2·2H2O (CoZn-NO3), [Ni2Zn3(OH)8](NO3)2·2H2O (NiZn-NO3) and [Zn5(OH)8](NO3)2·2H2O (Zn-NO3). It proved possible to intercalate diclofenac and naproxen into all three HDSs. In contrast, Val could be intercalated into CoZn-NO3 but when it was reacted with Zn-NO3 the HDS structure was destroyed, and the product comprised ZnO. Successful intercalation was verified by X-ray diffraction, IR spectroscopy, and elemental microanalysis. Molecular dynamics simulations showed the Dic and Nap ions to arrange themselves in an "X" shape in the interlayer space, forming a bilayer. Val was found to adopt a position with its aliphatic groups parallel to the HDS layer, again in a bilayer. In situ time resolved X-ray diffraction experiments revealed that intercalation of Dic and Nap into CoZn-NO3 and Zn-NO3 is mechanistically complex, with a number of intermediate phases observed. In contrast, the intercalation of all three guests into NiZn-NO3 and of Val into CoZn-NO3 are simple one step reactions proceeding directly from the starting material to the product. The HDS-drug composites were found to have sustained release profiles.

Intercalation of iron hexacyano complexes in Zn,Al hydrotalcite. Part 2. A mid-infrared and Raman spectroscopic study

International Nuclear Information System (INIS)

Kloprogge, J.T.; Weier, Matt; Crespo, Inmaculada; Ulibarri, M.A.; Barriga, Cristobalina; Rives, V.; Martens, W.N.; Frost, R.L.

2004-01-01

Combined mid-IR and Raman spectroscopies indicate that intercalation of hexacyanoferrate (II) and (III) in the interlayer space of a Zn,Al hydrotalcite dried at 60 deg. C leads to layered solids where the intercalated species correspond to both hexacyanoferrate(II) and (III). This is an indication that depending on the oxidation state of the initial hexacyanoferrate, partial oxidation and reduction takes place upon intercalation. The symmetry of the intercalated hexacyanoferrate decreases from O h existing in the free anions to D 3d . The observation of a broad band around 2080 cm -1 is indicative of the removal of cyanide from the intercalation complex to the outside surface of the crystals. Its position in the intercalation complex is probably filled by a hydroxyl group

Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

KAUST Repository

Bruner, Christopher; Miller, Nichole C.; McGehee, Michael D.; Dauskardt, Reinhold H.

2013-01-01

The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective and low temperature transition metal intercalation in layered tellurides

Science.gov (United States)

Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi

2016-01-01

Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid. PMID:27966540

Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

KAUST Repository

Bruner, Christopher

2013-01-17

The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermodynamics and kinetics of phase transformation in intercalation battery electrodes - phenomenological modeling

Energy Technology Data Exchange (ETDEWEB)

Lai Wei, E-mail: laiwei@msu.ed [Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824 (United States); Ciucci, Francesco [Heidelberg Graduate School of Mathematical and Computational Methods for the Sciences, University of Heidelberg, INF 368 D - 69120 Heidelberg (Germany)

2010-12-15

Thermodynamics and kinetics of phase transformation in intercalation battery electrodes are investigated by phenomenological models which include a mean-field lattice-gas thermodynamic model and a generalized Poisson-Nernst-Planck equation set based on linear irreversible thermodynamics. The application of modeling to a porous intercalation electrode leads to a hierarchical equivalent circuit with elements of explicit physical meanings. The equivalent circuit corresponding to the intercalation particle of planar, cylindrical and spherical symmetry is reduced to a diffusion equation with concentration dependent diffusivity. The numerical analysis of the diffusion equation suggests the front propagation behavior during phase transformation. The present treatment is also compared with the conventional moving boundary and phase field approaches.

Lithium intercalation in the LiLaNb{sub 2}O{sub 7} perovskite structure; Intercalation du lithium dans la structure perovskite LiLaNb{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Bohnke, C.; Bohnke, O.; Fourquet, J.L. [Universite du Maine, 72 - Le Mans (France). Laboratoire des Fluorures

1996-12-31

ABO{sub 3} perovskite-type oxides having vacancies in the A-sites of their structure are interesting candidates for solid electrolytes when their A-sites are occupied by Li{sup +} ions having a high mobility. This is the case with the [Li{sub 3x}La{sub 2/3-x}]TiO{sub 3} solid solution compound which has a 10{sup -3} S cm{sup -1} ionic conductivity at ambient temperature. Electrochemical intercalation in this material is possible thanks to the presence of Ti{sup 4+} but the small amount of vacancies (0.33 maximum) leads to a low intercalation rate. In order to solve this problem, the LiLaNb{sub 2}O{sub 7} material which has a greater amount of vacancies has been studied and the results relative to the electrochemical intercalation of lithium in this perovskite are presented. The thermodynamical and kinetics properties of the lithium intercalation reaction have been studied by intermittent galvano-static discharges and impedance spectroscopy in LiClO{sub 4}-propylene carbonate medium. (J.S.) 7 refs.

Lithium intercalation in the LiLaNb{sub 2}O{sub 7} perovskite structure; Intercalation du lithium dans la structure perovskite LiLaNb{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Bohnke, C; Bohnke, O; Fourquet, J L [Universite du Maine, 72 - Le Mans (France). Laboratoire des Fluorures

1997-12-31

ABO{sub 3} perovskite-type oxides having vacancies in the A-sites of their structure are interesting candidates for solid electrolytes when their A-sites are occupied by Li{sup +} ions having a high mobility. This is the case with the [Li{sub 3x}La{sub 2/3-x}]TiO{sub 3} solid solution compound which has a 10{sup -3} S cm{sup -1} ionic conductivity at ambient temperature. Electrochemical intercalation in this material is possible thanks to the presence of Ti{sup 4+} but the small amount of vacancies (0.33 maximum) leads to a low intercalation rate. In order to solve this problem, the LiLaNb{sub 2}O{sub 7} material which has a greater amount of vacancies has been studied and the results relative to the electrochemical intercalation of lithium in this perovskite are presented. The thermodynamical and kinetics properties of the lithium intercalation reaction have been studied by intermittent galvano-static discharges and impedance spectroscopy in LiClO{sub 4}-propylene carbonate medium. (J.S.) 7 refs.

Evolution of interfacial intercalation chemistry on epitaxial graphene/SiC by surface enhanced Raman spectroscopy

International Nuclear Information System (INIS)

Ferralis, Nicola; Carraro, Carlo

2014-01-01

Highlights: • H-intercalated epitaxial graphene–SiC interface studied with surface enhanced Raman. • Evolution of graphene and H–Si interface with UV-ozone, annealing and O-exposure. • H–Si interface and quasi-freestanding graphene are retained after UV-ozone treatment. • Enhanced ozonolytic reactivity at the edges of H-intercalated defected graphene. • Novel SERS method for characterizing near-surface graphene–substrate interfaces. - Abstract: A rapid and facile evaluation of the effects of physical and chemical processes on the interfacial layer between epitaxial graphene monolayers on SiC(0 0 0 1) surfaces is essential for applications in electronics, photonics, and optoelectronics. Here, the evolution of the atomic scale epitaxial graphene-buffer-layer–SiC interface through hydrogen intercalation, thermal annealings, UV-ozone etching and oxygen exposure is studied by means of single microparticle mediated surface enhanced Raman spectroscopy (smSERS). The evolution of the interfacial chemistry in the buffer layer is monitored through the Raman band at 2132 cm −1 corresponding to the Si-H stretch mode. Graphene quality is monitored directly by the selectively enhanced Raman signal of graphene compared to the SiC substrate signal. Through smSERS, a simultaneous correlation between optimized hydrogen intercalation in epitaxial graphene/SiC and an increase in graphene quality is uncovered. Following UV-ozone treatment, a fully hydrogen passivated interface is retained, while a moderate degradation in the quality of the hydrogen intercalated quasi-freestanding graphene is observed. While hydrogen intercalated defect free quasi-freestanding graphene is expected to be robust upon UV-ozone, thermal annealing, and oxygen exposure, ozonolytic reactivity at the edges of H-intercalated defected graphene results in enhanced amorphization of the quasi-freestanding (compared to non-intercalated) graphene, leading ultimately to its complete etching

Evolution of interfacial intercalation chemistry on epitaxial graphene/SiC by surface enhanced Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Ferralis, Nicola, E-mail: ferralis@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Carraro, Carlo [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States)

2014-11-30

Highlights: • H-intercalated epitaxial graphene–SiC interface studied with surface enhanced Raman. • Evolution of graphene and H–Si interface with UV-ozone, annealing and O-exposure. • H–Si interface and quasi-freestanding graphene are retained after UV-ozone treatment. • Enhanced ozonolytic reactivity at the edges of H-intercalated defected graphene. • Novel SERS method for characterizing near-surface graphene–substrate interfaces. - Abstract: A rapid and facile evaluation of the effects of physical and chemical processes on the interfacial layer between epitaxial graphene monolayers on SiC(0 0 0 1) surfaces is essential for applications in electronics, photonics, and optoelectronics. Here, the evolution of the atomic scale epitaxial graphene-buffer-layer–SiC interface through hydrogen intercalation, thermal annealings, UV-ozone etching and oxygen exposure is studied by means of single microparticle mediated surface enhanced Raman spectroscopy (smSERS). The evolution of the interfacial chemistry in the buffer layer is monitored through the Raman band at 2132 cm{sup −1} corresponding to the Si-H stretch mode. Graphene quality is monitored directly by the selectively enhanced Raman signal of graphene compared to the SiC substrate signal. Through smSERS, a simultaneous correlation between optimized hydrogen intercalation in epitaxial graphene/SiC and an increase in graphene quality is uncovered. Following UV-ozone treatment, a fully hydrogen passivated interface is retained, while a moderate degradation in the quality of the hydrogen intercalated quasi-freestanding graphene is observed. While hydrogen intercalated defect free quasi-freestanding graphene is expected to be robust upon UV-ozone, thermal annealing, and oxygen exposure, ozonolytic reactivity at the edges of H-intercalated defected graphene results in enhanced amorphization of the quasi-freestanding (compared to non-intercalated) graphene, leading ultimately to its complete etching.

Fabrication of a single layer graphene by copper intercalation on a SiC(0001) surface

International Nuclear Information System (INIS)

Yagyu, Kazuma; Tochihara, Hiroshi; Tomokage, Hajime; Suzuki, Takayuki; Tajiri, Takayuki; Kohno, Atsushi; Takahashi, Kazutoshi

2014-01-01

Cu atoms deposited on a zero layer graphene grown on a SiC(0001) substrate, intercalate between the zero layer graphene and the SiC substrate after the thermal annealing above 600 °C, forming a Cu-intercalated single layer graphene. On the Cu-intercalated single layer graphene, a graphene lattice with superstructure due to moiré pattern is observed by scanning tunneling microscopy, and specific linear dispersion at the K ¯ point as well as a characteristic peak in a C 1s core level spectrum, which is originated from a free-standing graphene, is confirmed by photoemission spectroscopy. The Cu-intercalated single layer graphene is found to be n-doped

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

Energy Technology Data Exchange (ETDEWEB)

Novo, Joao Batista Marques [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil)]. E-mail: jbmnovo@quimica.ufpr.br; Batista, Fabio Roberto [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Cunha, Carlos Jorge da [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Dias, Lauro Camargo Jr. [Departamento de Quimica, Universidade Federal do Parana, CP 19081, 81531-990 Curitiba-PR (Brazil); Teixeira Pessine, Francisco Benedito [Instituto de Quimica, Universidade Estadual de Campinas, CP 6154, 13084-971 Campinas-SP (Brazil)

2007-05-15

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), {alpha}-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times.

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

International Nuclear Information System (INIS)

Novo, Joao Batista Marques; Batista, Fabio Roberto; Cunha, Carlos Jorge da; Dias, Lauro Camargo Jr.; Teixeira Pessine, Francisco Benedito

2007-01-01

Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), α-methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos' stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times

Sensors properties of an alkylamine-intercalated kaolinite material towards the voltammetric preconcentration of [Ru(CN)6]4- at a clay-modified electrode

Energy Technology Data Exchange (ETDEWEB)

Tonle, I.K. [Ottawa Univ., ON (Canada). Dept. of Chemistry, Center for Catalysis Research and Innovation; Yanoude Univ. (Cameroon). Laboratoire de Chimie Analytique, Faculte des Sciences; Dschang Univ. (Cameroon). Dept. de Chimie; Bouwe, B.; Rose, G.; Ngameni, E. [Yanoude Univ. (Cameroon). Laboratoire de Chimie Analytique, Faculte des Sciences; Detellier, C. [Yanoude Univ. (Cameroon). Laboratoire de Chimie Analytique, Faculte des Sciences

2008-07-01

This study discussed the sensor properties of a kaolinite material in relation to the voltammetric preconcentration of ruthenium (Ru) anions in a clay-modified electrode. An organoclay was intercalated at room temperature with a layer of hexylamine. Dimethylsulfoxide (DMSO) was intercalated between the clay layers and displaced in wet conditions by the akylamine. The modified clay was then characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The analyses confirmed the incorporation of the hexylamine between the kaolinite platelets. The organokaolinite was then studied for use as a preconcentration agent when coated on the active surface of a glassy carbon electrode for the accumulation of [Ru(CN)6]4- anions in a hydrochloric acid medium. Factors that influenced the conductivity of the film and the diffusion of the electroactive species within the film included the concentration of the electrolyte, and the redox probe. The study showed that kaolinite can be used as a material in electrochemical sensors.

Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

KAUST Repository

Cates, Nichole C.

2009-12-09

We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

Tuning the Properties of Polymer Bulk Heterojunction Solar Cells by Adjusting Fullerene Size to Control Intercalation

KAUST Repository

Cates, Nichole C.; Gysel, Roman; Beiley, Zach; Miller, Chad E.; Toney, Michael F.; Heeney, Martin; McCulloch, Iain; McGehee, Michael D.

2009-01-01

We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells. © 2009 American Chemical Society.

Comparison of 6-thioguanine-resistant mutation and sister chromatid exchanges in Chinese hamster V79 cells with forty chemical and physical agents

International Nuclear Information System (INIS)

Nishi, Y.; Hasegawa, M.M.; Taketomi, M.; Ohkawa, Y.; Inui, N.

1984-01-01

The induction of sister chromatid exchanges (SCE) and mutation at the hypoxanthine-guanine phosphoribosyl transferase locus and toxicities of 40 different chemical and physical agents were examined on Chinese hamster V79 cells. These agents included mono-, di-, tri-, and polyfunctional alkylating agents, intercalators, gamma-rays, and UV light irradiation. Mutation was measured as resistance to 6-thioguanine and toxicity as loss of cell-plating efficiency. SCE were examined 29 hr after treatment. With the agents examined, a highly positive correlation existed between SCE-inducing and mutagenic potencies, when expressed as increase in the number per a unit dose over the control values. But the great difference of the ratios of mutagenic potencies versus SCE-inducing potencies among agents was observed, the maximal difference in the ratios being about 200-fold. The agents that showed the higher values of the ratio (agents producing more mutations than SCE) were bleomycin, cobalt-60 gamma-rays, all ethylating agents (N-ethyl-N-nitrosourea, N-ethyl-N'-nitro-N-nitrosoguanidine, ethyl methanesulfonate, and diethylsulfate), N-propyl-N-nitrosourea, N-butyl-N-nitrosourea, isopropyl methanesulfonate, intercalating acridine compounds (2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]-acridine X 2HCl and 2-methoxy-6-chloro-9-[3-(chloroethyl)-aminopropylamino]acridine 2HCl) and UV light at 254 nm

Dynamics of water intercalation fronts in a nano-layered synthetic silicate: A synchrotron X-ray scattering study

International Nuclear Information System (INIS)

Lovoll, G.; Sandnes, B.; Meheust, Y.; Maloy, K.J.; Fossum, J.O.; Silva, G.J. da; Mundim, M.S.P.; Droppa, R. Jr.; Fonseca, D.M.

2005-01-01

We performed synchrotron X-ray scattering studies of the dynamics of the water intercalation front in a Na-Fluorohectorite clay. Like other smectite clays, fluorohectorite particles can swell due to intercalation of successive water layers. Monitoring the intensities of Bragg peaks of the known 1- and 2-water-layer hydration states at different positions in the sample enabled spatial and temporal measurement of the proportions of the different hydration states. From experiments with controlled temperature and an imposed humidity gradient on a quasi one-dimensional powder sample, we were able to localize the intercalation front and demonstrate that the width of this front was smaller than 2 mm after penetrating 9 mm into the sample. The speed at which the intercalation front advanced through the sample during the diffusion process was shown to decrease with time. The diffraction signature of random water intercalation in the vicinity of the intercalation front also provided information on the changes in the water content of the mesopores around clay particles

Superlattice Effects in Graphite Intercalation Compounds.

Science.gov (United States)

1986-04-15

away from ;le[ Isy.st,.mns (r lin( nl :; atars ) and look for nonlinear dynamical effects -. m,,5,: U~ i,: ,1 : s y’t, rns, a3iioh m i Josephson...Intercalation Coaanm, Chemistry Dept., Northeast(.rn,, February 25, 1935. ( iv) "Giant Magnetic Interaction and Domain Dynamics in Twe -. "Dimensions," hoston

Iron Intercalation in Covalent-Organic Frameworks: A Promising Approach for Semiconductors

OpenAIRE

Pakhira, Srimanta; Lucht, Kevin P.; Mendoza-Cortes, Jose L.

2017-01-01

Covalent-organic frameworks (COFs) are intriguing platforms for designing functional molecular materials. Here, we present a computational study based on van der Waals dispersion-corrected hybrid density functional theory (DFT-D) to design boroxine-linked and triazine-linked COFs intercalated with Fe. Keeping the original $P-6m2$ symmetry of the pristine COF (COF-Fe-0), we have computationally designed seven new COFs by intercalating Fe atoms between two organic layers. The equilibrium struct...

An intercalated BSc degree is associated with higher marks in subsequent medical school examinations

Directory of Open Access Journals (Sweden)

Sinclair Hazel

2009-05-01

Full Text Available Abstract Background To compare medical students on a modern MBChB programme who did an optional intercalated degree with their peers who did not intercalate; in particular, to monitor performance in subsequent undergraduate degree exams. Methods This was a retrospective, observational study of anonymised databases of medical student assessment outcomes. Data were accessed for graduates, University of Aberdeen Medical School, Scotland, UK, from the years 2003 to 2007 (n = 861. The main outcome measure was marks for summative degree assessments taken after intercalating. Results Of 861 medical students, 154 (17.9% students did an intercalated degree. After adjustment for cohort, maturity, gender and baseline (3rd year performance in matching exam type, having done an IC degree was significantly associated with attaining high (18–20 common assessment scale (CAS marks in three of the six degree assessments occurring after the IC students rejoined the course: the 4th year written exam (p th year OSCE (p = 0.001 and the 5th year Elective project (p = 0.010. Conclusion Intercalating was associated with improved performance in Years 4 and 5 of the MBChB. This improved performance will further contribute to higher academic ranking for Foundation Year posts. Long-term follow-up is required to identify if doing an optional intercalated degree as part of a modern medical degree is associated with following a career in academic medicine.

Preparation, quantitative surface analysis, intercalation characteristics and industrial implications of low temperature expandable graphite

Science.gov (United States)

Peng, Tiefeng; Liu, Bin; Gao, Xuechao; Luo, Liqun; Sun, Hongjuan

2018-06-01

Expandable graphite is widely used as a new functional carbon material, especially as fire-retardant; however, its practical application is limited due to the high expansion temperature. In this work, preparation process of low temperature and highly expandable graphite was studied, using natural flake graphite as raw material and KMnO4/HClO4/NH4NO3 as oxidative intercalations. The structure, morphology, functional groups and thermal properties were characterized during expanding process by Fourier transform infrared spectroscopy (FTIR), Raman spectra, thermo-gravimetry differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). The analysis showed that by oxidation intercalation, some oxygen-containing groups were grafted on the edge and within the graphite layer. The intercalation reagent entered the graphite layer to increase the interlayer spacing. After expansion, the original flaky expandable graphite was completely transformed into worm-like expanded graphite. The order of graphite intercalation compounds (GICs) was proposed and determined to be 3 for the prepared expandable graphite, based on quantitative XRD peak analysis. Meanwhile, the detailed intercalation mechanisms were also proposed. The comprehensive investigation paved a benchmark for the industrial application of such sulfur-free expanded graphite.

Layered double hydroxides as supports for intercalation and sustained release of antihypertensive drugs

International Nuclear Information System (INIS)

Xia Shengjie; Ni Zheming; Xu Qian; Hu Baoxiang; Hu Jun

2008-01-01

Zn/Al layered double hydroxides (LDHs) were intercalated with the anionic antihypertensive drugs Enalpril, Lisinopril, Captopril and Ramipril by using coprecipitation or ion-exchange technique. TG-MS analyses suggested that the thermal stability of Ena - , Lis - (arranged with monolayer, resulted from X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) analysis was enhanced much more than Cap - and Ram - (arranged with bilayer). The release studies show that the release rate of all samples markedly decreased in both pH 4.25 and 7.45. However, the release time of Ena - , Lis - were much longer compared with Cap - , Ram - in both pH 4.25 and 7.45, it is possible that the intercalated guests, arranged with monolayer in the interlayer, show lesser repulsive force and strong affinity with the LDH layers. And the release data followed both the Higuchi-square-root law and the first-order equation well. Based on the analysis of batch release, intercalated structural models as well as the TG-DTA results, we conclude that for drug-LDH, stronger the affinity between intercalated anions and the layers is, better the thermal property and the stability to the acid attack of drug-LDH, and the intercalated anions are easier apt to monolayer arrangement within the interlayer, were presented. - Graphical abstract: A series of antihypertensive drugs including Enalpril, Lisinopril, Captopril and Ramipril were intercalated into Zn/Al-NO 3 -LDHs successfully by coprecipitation or ion-exchange technique. We focus on the structure, thermal property and low/controlled release property of as-synthesized drug-LDH composite intended for the possibility of applying these LDH-antihypertensive nanohybrids in drug delivery and controlled release systems

Mössbauer study of pH dependence of iron-intercalation in montmorillonite

Energy Technology Data Exchange (ETDEWEB)

Kuzmann, E., E-mail: kuzmann@caesar.elte.hu [Eötvös Loránd University, Institute of Chemistry (Hungary); Garg, V. K.; Singh, H.; Oliveira, A. C. de; Pati, S. S. [University of Brasília, Institute of Physics (Brazil); Homonnay, Z.; Rudolf, M. [Eötvös Loránd University, Institute of Chemistry (Hungary); Molnár, Á. M.; Kovács, E. M. [University of Debrecen, Imre Lajos Isotope Laboratory, Department of Colloid and Environmental Chemistry (Hungary); Baranyai, E. [University of Debrecen, Department of Inorganic and Analytical Chemistry (Hungary); Kubuki, S. [Tokyo Metropolitan University, Department of Chemistry (Japan); Nagy, N. M.; Kónya, J. [University of Debrecen, Imre Lajos Isotope Laboratory, Department of Colloid and Environmental Chemistry (Hungary)

2016-12-15

{sup 57}Fe Mössbauer spectroscopy and XRD have successfully been applied to show the incorporation of Fe ion into the interlayer space of montmorillonite via treatment with FeCl {sub 3} in acetone. The 78K {sup 57}Fe Mössbauer spectra of montmorillonite samples reflected magnetically split spectrum part indicating the intercalation of iron into the interlayer of montmorillonite via the treatment with FeCl {sub 3}+acetone and washed with water until the initial pH=2.3 increased to pH=4.14. It was found that the occurrence of intercalated iron in the form of oxide-oxihydroxide in montmorillonite increases with the pH. Intercalation was confirmed by the gradual increase in the basal spacing d{sub 001} with pH.

Synthesis, antitumour and antioxidant activities of novel α,β-unsaturated ketones and related heterocyclic analogues: EGFR inhibition and molecular modelling study.

Science.gov (United States)

El-Husseiny, Walaa M; El-Sayed, Magda A-A; Abdel-Aziz, Naglaa I; El-Azab, Adel S; Ahmed, Esam R; Abdel-Aziz, Alaa A-M

2018-12-01

New α,β-unsaturated ketones 4a,b; 5a-c; and 6a,b; as well as 4-H pyran 7; pyrazoline 8a,b; isoxazoline 9; pyridine 10-11; and quinoline-4-carboxylic acid 12a,b derivatives were synthesized and evaluated for in vitro antitumour activity against HepG2, MCF-7, HeLa, and PC-3 cancer cell lines. Antioxidant activity was investigated by the ability of these compounds to scavenge the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS •+ ). Compounds 6a, 6b, 7, and 8b exhibited potent antitumour activities against all tested cell lines with [IC 50 ] ≅5.5-18.1 µΜ), in addition to significantly high ABTS •+ scavenging activities. In vitro EGFR kinase assay for 6a, 6b, 7, and 8b as the most potent antitumour compounds showed that; compounds 6b, and 7 exhibited worthy EGFR inhibition activity with IC 50 values of 0.56 and 1.6 µM, respectively, while compounds 6a and 8b showed good inhibition activity with IC 50 values of 4.66 and 2.16 µM, respectively, compared with sorafenib reference drug (IC 50  = 1.28 µM). Molecular modelling studies for compounds 6b, 7, and 8b were conducted to exhibit the binding mode towards EGFR kinase, which showed similar interaction with erlotinib.

Intercalation of Toluidines into Alpha - Zirconium Hydrogenphosphate

Czech Academy of Sciences Publication Activity Database

Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

2006-01-01

Roč. 55, č. 3-4 (2006), s. 289-293 ISSN 0923-0750 R&D Projects: GA ČR(CZ) GA203/05/2306 Institutional research plan: CEZ:AV0Z40500505 Keywords : intercalation Subject RIV: CA - Inorganic Chemistry Impact factor: 1.251, year: 2006

Antitumour evaluation of di-(2-ethylhexyl) phthalate (DEHP) isolated from Calotropis gigantea L. flower.

Science.gov (United States)

Habib, Muhammad Rowshanul; Karim, Muhammad Rezaul

2012-12-01

The objective of the study is to explore the anticancer activity of di-(2-ethylhexyl) phthalate (DEHP) isolated from Calotropis gigantea flower against Ehrlich ascites carcinoma cells (EAC) in Swiss albino mice. The activity of DEHP was evaluated at doses of 10, 20 and 40 mg kg-1 body mass applied intraperitoneally. DEHP showed a significant decrease in viable cell count (p SALP and SGOT) to normal level. Results of this study indicate that DEHP show potent dose dependent antitumour activity against EAC in vivo.

Drug delivery system for an anticancer agent, chlorogenate-Zn/Al-layered double hydroxide nanohybrid synthesised using direct co-precipitation and ion exchange methods

Energy Technology Data Exchange (ETDEWEB)

Barahuie, Farahnaz [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Hussein, Mohd Zobir, E-mail: mzobir@putra.upm.edu.my [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Arulselvan, Palanisamy [Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Fakurazi, Sharida [Laboratory of Vaccines and Immunotherapeutics, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Department of Human Anatomy, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Zainal, Zulkarnain [Materials Synthesis and Characterization Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

2014-09-15

A nano-structured drug-inorganic clay hybrid involving an active anticancer compound, which is chlorogenic acid (CA) intercalated into Zn/Al-layered double hydroxide, has been assembled via ion-exchange and co-precipitation methods to form a nanohybrid CZAE (a chlorogenic acid-Zn/Al nanohybrid synthesised using an ion-exchange method) and CZAC (a chlorogenic acid-Zn/Al nanohybrid synthesised using a direct method), respectively. The X-ray diffraction (XRD) results confirmed that the CA-LDH had a hybrid structure in which the anionic chlorogenate is arranged between the interlayers as a horizontal monolayer at 90 and 20° angles from the x axis for CZAE and CZAC, respectively. Both nanohybrids have the properties of mesoporous materials. The high loading percentage of chlorogenic acid (approximately 43.2% for CZAE and 45.3% for CZAC) with basal spacings of 11.7 and 12.6 Å for CZAE and CZAC, respectively, corroborates the successful intercalation of chlorogenic acid into the interlayer gallery of layered double hydroxides. Free chlorogenic acid and the synthesised nanocomposites (CZAE, CZAC) were assessed for their cytotoxicity against various cancer cells. The Fourier transform infrared data supported the formation of both nanohybrids, and a thermal analysis showed that the nanohybrids are more thermally stable than their counterparts. The chlorogenate shows a sustained release, and the release rate of chlorogenate from CZAE and CZAC nanohybrids at pH 7.4 is remarkably lower than that at pH 4.8 due to their different release mechanisms. The release rate of chlorogenate from both nanohybrids can be described as pseudo-second order. The present investigation revealed the potential of the nanohybrids to enhance the in vitro anti-tumour effect of chlorogenic acid in liver and lung cancer cells in vitro. - Highlights: • We intercalated chlorogenic into Zn/Al-layered double hydroxide by ion-exchange and coprecipitation methods. • The two methods gave nanocomposites

Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

Energy Technology Data Exchange (ETDEWEB)

Chen, Jing; Zhao, Minggang, E-mail: zhaomg@ouc.edu.cn; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang, E-mail: sgchen@ouc.edu.cn

2016-07-15

Highlights: • A MWCNTs/rGO/ZnO quantum dots intercalation nanoballs decorated 3D hierarchical architecture is fabricated on Ni foam. • Large numbers of ZnO quantum dots are intercalated by rGO sheets to construct hierarchical nanoballs. • Improved mechanical, kinetic and electrochemical properties are found. • The strong interfacial effect makes the material can be used for selective detection of dopamine, ascorbic acid and uric acid. - Abstract: ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

Synthesis of reduced graphene oxide intercalated ZnO quantum dots nanoballs for selective biosensing detection

International Nuclear Information System (INIS)

Chen, Jing; Zhao, Minggang; Li, Yingchun; Fan, Sisi; Ding, Longjiang; Liang, Jingjing; Chen, Shougang

2016-01-01

Highlights: • A MWCNTs/rGO/ZnO quantum dots intercalation nanoballs decorated 3D hierarchical architecture is fabricated on Ni foam. • Large numbers of ZnO quantum dots are intercalated by rGO sheets to construct hierarchical nanoballs. • Improved mechanical, kinetic and electrochemical properties are found. • The strong interfacial effect makes the material can be used for selective detection of dopamine, ascorbic acid and uric acid. - Abstract: ZnO quantum dots (QDs), reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) are always used in sensors due to their excellent electrochemical characteristics. In this work, ZnO QDs were intercalated by rGO sheets with cross-linked MWCNTs to construct intercalation nanoballs. A MWCNTs/rGO/ZnO QDs 3D hierarchical architecture was fabricated on supporting Ni foam, which exhibited excellent mechanical, kinetic and electrochemical properties. The intercalation construction can introduce strong interfacial effects to improve the surface electronic state. The selectively determinate of uric acid, dopamine, and ascorbic acid by an electrode material using distinct applied potentials was realized.

Fabrication of graphene device from graphite intercalation compound

Science.gov (United States)

Yagi, Ryuta; Kobara, Hiroaki; Shimomura, Midori; Tahara, Fumiya; Fukada, Seiya

2012-02-01

The mechanical exfoliation of graphite is possibly the simplest and practical method in laboratories to obtain graphene flakes for scientific research. However efficiency for obtaining graphene, with desired layer-number and size, depends largely on crystal specific characters, eg., dislocations. To improve the issue, we have adopted graphite intercalation compound (GIC) instead of graphite for a starting material. Generally, GIC is chemically active. We used SbCl5- GIC, which is stable in the atmosphere. Stage structure of SbCl5-GIC could be tuned by temperature of intercalation. We found that considerable number of undoped graphene flakes coexisted with thin SbCl5-GIC flakes, on a substrate where flakes were transferred.?Statistical inspection of number of graphene layer indicated that it is significantly dependent on the stage number of GIC.

Bromine intercalated graphite for lightweight composite conductors

KAUST Repository

Amassian, Aram

2017-07-20

A method of fabricating a bromine-graphite/metal composite includes intercalating bromine within layers of graphite via liquid-phase bromination to create brominated-graphite and consolidating the brominated-graphite with a metal nanopowder via a mechanical pressing operation to generate a bromine-graphite/metal composite material.

Formation Dynamics of Potassium-Based Graphite Intercalation Compounds: An Ab Initio Study

Science.gov (United States)

Jiang, Xiankai; Song, Bo; Tománek, David

2018-04-01

This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. We use ab initio molecular dynamics simulations to study the microscopic dynamics of potassium intercalation in graphite. Upon adsorbing on graphite from the vapor phase, K atoms transfer their valence charge to the substrate. K atoms adsorbed on the surface diffuse rapidly along the graphene basal plane and eventually enter the interlayer region following a "U -turn" across the edge, gaining additional energy. This process is promoted at higher coverages associated with higher K pressure, leading to the formation of a stable intercalation compound. We find that the functionalization of graphene edges is an essential prerequisite for intercalation since bare edges reconstruct and reconnect, closing off the entry channels for the atoms.

Hydrogen intercalation of single and multiple layer graphene synthesized on Si-terminated SiC(0001) surface

International Nuclear Information System (INIS)

Sołtys, Jakub; Piechota, Jacek; Ptasinska, Maria; Krukowski, Stanisław

2014-01-01

Ab initio density functional theory simulations were used to investigate the influence of hydrogen intercalation on the electronic properties of single and multiple graphene layers deposited on the SiC(0001) surface (Si-face). It is shown that single carbon layer, known as a buffer layer, covalently bound to the SiC substrate, is liberated after hydrogen intercalation, showing characteristic Dirac cones in the band structure. This is in agreement with the results of angle resolved photoelectron spectroscopy measurements of hydrogen intercalation of SiC-graphene samples. In contrast to that hydrogen intercalation has limited impact on the multiple sheet graphene, deposited on Si-terminated SiC surface. The covalently bound buffer layer is liberated attaining its graphene like structure and dispersion relation typical for multilayer graphene. Nevertheless, before and after intercalation, the four layer graphene preserved the following dispersion relations in the vicinity of K point: linear for (AAAA) stacking, direct parabolic for Bernal (ABAB) stacking and “wizard hat” parabolic for rhombohedral (ABCA) stacking

Intercalating cobalt between graphene and iridium (111): Spatially dependent kinetics from the edges

Science.gov (United States)

Vlaic, Sergio; Rougemaille, Nicolas; Kimouche, Amina; Burgos, Benito Santos; Locatelli, Andrea; Coraux, Johann

2017-10-01

Using low-energy electron microscopy, we image in real time the intercalation of a cobalt monolayer between graphene and the (111) surface of iridium. Our measurements reveal that the edges of a graphene flake represent an energy barrier to intercalation. Based on a simple description of the growth kinetics, we estimate this energy barrier and find small, but substantial, local variations. These local variations suggest a possible influence of the graphene orientation with respect to its substrate and of the graphene edge termination on the energy value of the barrier height. Besides, our measurements show that intercalated cobalt is energetically more favorable than cobalt on bare iridium, indicating a surfactant role of graphene.

Electron doping through lithium intercalation to interstitial channels in tetrahedrally bonded SiC

Energy Technology Data Exchange (ETDEWEB)

Sakai, Yuki [Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Center for Computational Materials, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Oshiyama, Atsushi [Department of Applied Physics, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2015-11-07

We report on first-principles calculations that clarify the effect of lithium atom intercalation into zinc blende 3C-silicon carbide (3C-SiC) on electronic and structural properties. Lithium atoms inside 3C-SiC are found to donate electrons to 3C-SiC that is an indication of a new way of electron doping through the intercalation. The electrons doped into the conduction band interact with lithium cations and reduce the band spacing between the original valence and conduction bands. We have also found that a silicon monovacancy in 3C-SiC promotes the lithium intercalation, showing that the vacancy generation makes SiC as a possible anode material for lithium-ion battery.

Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative.

Science.gov (United States)

Cai, Enbo; Song, Xingzhuo; Han, Mei; Yang, Limin; Zhao, Yan; Li, Wei; Han, Jiahong; Tu, Shumei

2018-02-19

Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio of 1:2:2:0.5. The yield of ARG-V was up to 80%. ARG-V has strong anti-tumour activity in vivo and in vitro. The inhibitory rate of ARG-V was 69.2%, with less damage to the immune organs and different degrees of increased serum cytotoxicity. Moreover, the pharmacokinetics of ARG following oral administration and ARG-V following oral administration in rats were also studied. The C max and AUC values of ARG-V showed significant differences compared to ARG. The relative bioavailabilities of three doses of ARG-V compared to ARG were 664.7%, 741.5% and 812.9%. These pharmacokinetic results may be useful for further studies of the bioactive mechanism of ARG and provide a theoretical basic for clinical use.

Kaolinite Nanocomposite Platelets Synthesized by Intercalation and Imidization of Poly(styrene-co-maleic anhydride

Directory of Open Access Journals (Sweden)

Pieter Samyn

2015-07-01

Full Text Available A synthesis route is presented for the subsequent intercalation, exfoliation and surface modification of kaolinite (Kln by an imidization reaction of high-molecular weight poly(styrene-co-maleic anhydride or SMA in the presence of ammonium hydroxide. In a first step, the intercalation of ammonolyzed SMA by guest displacement of intercalated dimethylsulfoxide has been proven. In a second step, the imidization of ammonolyzed SMA at 160 °C results in exfoliation of the kaolinite layers and deposition of poly(styrene-co-maleimide or SMI nanoparticles onto the kaolinite surfaces. Compared with a physical mixture of Kln/SMI, the chemically reacted Kln/SMI provides more efficient exfoliation and hydrogen bonding between the nanoparticles and the kaolinite. The kaolinite nanocomposite particles are synthesized in aqueous dispersion with solid content of 65 wt %. The intercalation and exfoliation are optimized for a concentration ratio of Kln/SMI = 70:30, resulting in maximum intercalation and interlayer distance in combination with highest imide content. After thermal curing at 135 °C, the imidization proceeds towards a maximum conversion of the intermediate amic acid moieties. The changes in O–H stretching and kaolinite lattice vibrations have been illustrated by infrared and FT-Raman spectroscopy, which allow for a good quantification of concentration and imidization effects.

Intercalation compounds of vanadium pentoxide hydrated with metalporphyrins and lanthanide ions

International Nuclear Information System (INIS)

Oliveira, Herenilton Paulino

1994-01-01

The lamellar structure of the vanadium pentoxide matrix allows the intercalation of organic molecules, ions and conductor polymers. It is important to emphasize that the vanadium oxide matrix is an intrinsic semiconductor and presents electrochromic properties. In the beginning of this work the method of synthesis and the electrochemical and electrochromic properties were extensively explored. The effect of alkaline metal and lanthanide ions on the structure of vanadium oxide matrix was studied by X-ray and infrared spectroscopy. Moreover, the influence of those ions in the electrochemical, spectro electrochemical and magnetic properties were studied. Finally, some intercalation compounds containing porphyrins were prepared and characterized by elemental analysis, X-ray diffraction, and electronic, vibrational, Moessbauer and X-ray fluorescence spectroscopy. The electrochemical and spectro electrochemical properties were investigated. And the performance of an iron porphyrin based intercalation compound as catalyst for molecular oxygen reduction was evaluated using the rotating ring-disc electrode technique. (author)

High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

KAUST Repository

Bouhrara, M.

2011-09-06

We present 13 C high-resolution magic-angle-turning (MAT) and magic angle spinning nuclear magnetic resonance data of Cs and Rb intercalated single walled carbon nanotubes. We find two distinct phases at different intercalation levels. A simple charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites is the most probable alkali site.

Effectiveness of anti-tumour necrosis factor-α therapy in Danish patients with inflammatory bowel diseases

DEFF Research Database (Denmark)

Bank, Steffen; Andersen, Paal Skytt; Burisch, Johan

2015-01-01

Introduction: The objective of this study was to evaluate the outcome of anti-tumour necrosis factor-α (anti-TNF) treatment in a large cohort of patients with inflammatory bowel diseases (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC) in clinical practice and to establish a cohort...... in clinical trials. Funding: The work was funded by Health Research Fund of Central Denmark Region, Colitis-Crohn Foreningen and the University of Aarhus (PhD grant). Trial registration: Clinicaltrials NCT02322008....

Syntheses, structure and intercalation properties of low-dimensional ...

Indian Academy of Sciences (India)

Unknown

Successful intercalation reactions of compounds 1 and 2 with primary n- alkyl amines have ... and hexavalent metal phenylphosphonates12–17 with ..... Similarly potassium. (3) and ..... ponds to loss of one water molecule, whereas the stage at ...

Enhancing the efficiency of lithium intercalation in carbon nanotube bundles using surface functional groups.

Science.gov (United States)

Xiao, Shiyan; Zhu, Hong; Wang, Lei; Chen, Liping; Liang, Haojun

2014-08-14

The effect of surface functionalization on the ability and kinetics of lithium intercalation in carbon nanotube (CNT) bundles has been studied by comparing the dynamical behaviors of lithium (Li) ions in pristine and -NH2 functionalized CNTs via ab initio molecular dynamics simulations. It was observed that lithium intercalation has been achieved quickly for both the pristine and surface functionalized CNT bundle. Our calculations demonstrated for the first time that CNT functionalization improved the efficiency of lithium intercalation significantly at both low and high Li ion density. Moreover, we found that keeping the nanotubes apart with an appropriate distance and charging the battery at a rational rate were beneficial to achieve a high rate of lithium intercalation. Besides, the calculated adsorption energy curves indicated that the potential wells in the system of -NH2 functionalized CNT were deeper than that of the pristine CNT bundle by 0.74 eV, and a third energy minimum with a value of 2.64 eV existed at the midpoint of the central axis of the nanotube. Thus, it would be more difficult to remove Li ions from the nanotube interior after surface functionalization. The barrier for lithium diffusion in the interior of the nanotube is greatly decreased because of the surface functional groups. Based on these results, we would suggest to "damage" the nanotube by introducing defects at its sidewall in order to improve not only the capacity of surface functionalized CNTs but also the efficiency of lithium intercalation and deintercalation processes. Our results presented here are helpful in understanding the mechanism of lithium intercalation into nanotube bundles, which may potentially be applied in the development of CNT based electrodes.

Self-consistent electronic structure of a model stage-1 graphite acceptor intercalate

International Nuclear Information System (INIS)

Campagnoli, G.; Tosatti, E.

1981-04-01

A simple but self-consistent LCAO scheme is used to study the π-electronic structure of an idealized stage-1 ordered graphite acceptor intercalate, modeled approximately on C 8 AsF 5 . The resulting non-uniform charge population within the carbon plane, band structure, optical and energy loss properties are discussed and compared with available spectroscopic evidence. The calculated total energy is used to estimate migration energy barriers, and the intercalate vibration mode frequency. (author)

A survey of the sequence-specific interaction of damaging agents with DNA: emphasis on antitumor agents.

Science.gov (United States)

Murray, V

1999-01-01

This article reviews the literature concerning the sequence specificity of DNA-damaging agents. DNA-damaging agents are widely used in cancer chemotherapy. It is important to understand fully the determinants of DNA sequence specificity so that more effective DNA-damaging agents can be developed as antitumor drugs. There are five main methods of DNA sequence specificity analysis: cleavage of end-labeled fragments, linear amplification with Taq DNA polymerase, ligation-mediated polymerase chain reaction (PCR), single-strand ligation PCR, and footprinting. The DNA sequence specificity in purified DNA and in intact mammalian cells is reviewed for several classes of DNA-damaging agent. These include agents that form covalent adducts with DNA, free radical generators, topoisomerase inhibitors, intercalators and minor groove binders, enzymes, and electromagnetic radiation. The main sites of adduct formation are at the N-7 of guanine in the major groove of DNA and the N-3 of adenine in the minor groove, whereas free radical generators abstract hydrogen from the deoxyribose sugar and topoisomerase inhibitors cause enzyme-DNA cross-links to form. Several issues involved in the determination of the DNA sequence specificity are discussed. The future directions of the field, with respect to cancer chemotherapy, are also examined.

Manganese oxide electrode with excellent electrochemical performance for sodium ion batteries by pre-intercalation of K and Na ions.

Science.gov (United States)

Feng, Mengya; Du, Qinghua; Su, Li; Zhang, Guowei; Wang, Guiling; Ma, Zhipeng; Gao, Weimin; Qin, Xiujuan; Shao, Guangjie

2017-05-22

Materials with a layered structure have attracted tremendous attention because of their unique properties. The ultrathin nanosheet structure can result in extremely rapid intercalation/de-intercalation of Na ions in the charge-discharge progress. Herein, we report a manganese oxide with pre-intercalated K and Na ions and having flower-like ultrathin layered structure, which was synthesized by a facile but efficient hydrothermal method under mild condition. The pre-intercalation of Na and K ions facilitates the access of electrolyte ions and shortens the ion diffusion pathways. The layered manganese oxide shows ultrahigh specific capacity when it is used as cathode material for sodium-ion batteries. It also exhibits excellent stability and reversibility. It was found that the amount of intercalated Na ions is approximately 71% of the total charge. The prominent electrochemical performance of the manganese oxide demonstrates the importance of design and synthesis of pre-intercalated ultrathin layered materials.

Measurements of quadrupolar interaction by perturbed angular correltion method on intercalated 2H-TaS sub(2)

International Nuclear Information System (INIS)

Saitovitch, H.

1979-01-01

This work is based on our quadrupolar interaction (QI) measurements on intercalated 2H-TaS sub(2) coumponds. As intercalating elements we used the alcalines - Li, Na, K, Cs -as well as the NH sub(3) (ammonia) and C sub(6) H sub(5) N (pyridine) molecules. The (QI) measurements were performed via the differential perturbed angular correlation (DPAC) technique, using Ta sup(181) as the probe isotope, on the hydrated and anhidrous phases of the intercalated systems. Our results happened to be in better agreement with the ionic model, one of the accepted models used to describe the intercalation process, as well as the transfered charges quantities and its distribution in the intercalated systems. And by its side the measured quantities, quadrupole interaction frequencies (QIF) and their distributions δ, contributed to support and to improve the ionic model. A strong charge dynamics between the 2H-TaS sub(2) sandwiches was observed and a relation between the (QIF) changes and amount of transfered charge (e sup(-)/Ta) was established. The attempt to specify the numerical contributions to the (QI) changes arriving from the different components of the 2H-TaS sub(2) intercalated systems put in evidence the probable orbitals involved in the systems bonds. Finally the kinetics of the intercalation process to form the 2H-TaS sub(2) (Li) sub(x) system was followed continuously by the (DPAC) measurements. (author)

Impedance Simulation of a Li-Ion Battery with Porous Electrodes and Spherical Li+ Intercalation Particles

NARCIS (Netherlands)

Huang, R.W.J.M.; Chung, F.; Kelder, E.M.

2006-01-01

We present a semimathematical model for the simulation of the impedance spectra of a rechargeable lithium batteries consisting of porous electrodes with spherical Li+ intercalation particles. The particles are considered to have two distinct homogeneous phases as a result of the intercalation and

Electrochemical lithium and sodium intercalation into the tantalum-rich layered chalcogenides Ta2Se and Ta2Te3

International Nuclear Information System (INIS)

Lavela, P.; Tirado, J.L.

1999-01-01

Two-layered tantalum chalcogenides are evaluated as alkali metal intercalation hosts in lithium and sodium electrochemical cells. The metal-rich pseudo-two-dimensional solid Ta 2 Se shows a poor intercalation behaviour. Lithium reacts with the selenide by deintercalating selenium from the blocks of Ta-related b.c.c. structure leading to a collapse of the structure and the formation of tantalum metal. Sodium is reversibly intercalated to a limited extent leading to complex structural changes in the selenide, as revealed by electron diffraction. The two-dimensional telluride Ta 2 Te 3 allows a topotactic intercalation of lithium below 1 F/mol, while a more extended reaction leads to sample amorphization. The better intercalation behaviour of this solid can be related with the one-atom thick metal layer and the van der Waals gap separating tellurium atoms of successive layers. Sodium can be reversibly intercalated into Ta 2 Te 3 in sodium cells which show a good cycling behaviour. Exposure of the intercalated solid to water vapour allows the preparation of hydrated products with a monolayer or a bilayer of water molecules solvating sodium in the interlayer space. (orig.)

XRD, SEM and infrared study into the intercalation of sodium hexadecyl sulfate (SHS) into hydrocalumite.

Science.gov (United States)

Zhang, Ping; Wang, Tianqi; Zhang, Longlong; Wu, Daishe; Frost, Ray L

2015-12-05

Hydrocalumite (CaAl-LDH-Cl) interacted with a natural anionic surfactant, sodium hexadecyl sulfate (SHS), was performed using an intercalation method. To understand the intercalation behavior and characterize the resulting products, powder X-ray diffraction (XRD), scan electron microscopy (SEM) and mid-infrared (MIR) spectroscopy combined with near-infrared (NIR) spectroscopy technique were used. The XRD analysis indicated that SHS was intercalated into CaAl-LDH-Cl successfully, resulting in an expansion of the interlayer (from 0.78 nm to 2.74 nm). The bands of C-H stretching vibrations of SHS were observed in the near-infrared spectra, which indicated that the resulting products were indeed CaAl-LDH-SHS. In addition, the bands of water stretching vibrations and OH groups shifted to higher wavenumbers when SHS was intercalated into CaAl-LDH-Cl interlayer space. Copyright © 2015 Elsevier B.V. All rights reserved.

Experimental study of the anti-tumour activity and pharmacokinetics of arctigenin and its valine ester derivative

OpenAIRE

Cai, Enbo; Song, Xingzhuo; Han, Mei; Yang, Limin; Zhao, Yan; Li, Wei; Han, Jiahong; Tu, Shumei

2018-01-01

Arctigenin (ARG) is a functional active component that has important physiological and pharmacological activities. The anti-tumour and anti-inflammatory activities of ARG show good potential for application and development, but this material has the defect of low water solubility. In this experiment, the valine derivative of ARG (ARG-V) was designed and synthesized to overcome this disadvantage. The ARG amino acid, EDCI and DMAP were raw materials in the addition reaction, with a molar ratio ...

Strontium Metylphosphonate Trihydrate: An Example of a New Class of Host Materials for Intercalation Reactions - Synthesis, Structure and Intercalation Behavior

Czech Academy of Sciences Publication Activity Database

Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav; Růžička, A.; Trchová, Miroslava

2011-01-01

Roč. 6, leden (2011), s. 850-859 ISSN 1434-1948 R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : layered compounds * intercalates * solid-state structures Subject RIV: CA - Inorganic Chemistry Impact factor: 3.049, year: 2011

Câncer e agentes antineoplásicos ciclo-celular específicos e ciclo-celular não específicos que interagem com o DNA: uma introdução Cancer and cell cicle-specific and cell cicle nonspecific anticancer DNA-interactive agents: an introduction

Directory of Open Access Journals (Sweden)

Vera Lúcia de Almeida

2005-02-01

Full Text Available The chemotherapy agents against cancer may be classified as "cell cycle-specific" or "cell cycle-nonspecific". Nevertheless, several of them have their biological activity related to any kind of action on DNA such as: antimetabolic agents (DNA synthesis inhibition, inherently reactive agents (DNA alkylating electrophilic traps for macromolecular nucleophiles from DNA through inter-strand cross-linking - ISC - alkylation and intercalating agents (drug-DNA interactions inherent to the binding made due to the agent penetration in to the minor groove of the double helix. The earliest and perhaps most extensively studied and most heavily employed clinical anticancer agents in use today are the DNA inter-strand cross-linking agents.

Phonon studies of intercalated conductive polymers

Energy Technology Data Exchange (ETDEWEB)

Prassides, K; Bell, C J [School of Chemistry and Molecular Sciences, Univ. of Sussex, Brighton (United Kingdom); Dianoux, A J [Inst. Laue-Langevin, 38 - Grenoble (France); Chunguey, Wu; Kanatzidis, M G [Dept. of Chemistry, Michigan State Univ., East Lansing (United States)

1992-06-01

The phonon density-of-states of FeOCl, the conductive form of polyaniline and the intercalation compound (polyaniline)[sub 0.20]FeOCl(I) have been measured by the neutron time-of-flight technique. The results are discussed in the light of the conducting and structural properties of the materials. Compound I is oxidised by standing in air and the neutron measurements reveal substantial changes in the inorganic host skeleton. (orig.).

Intercalated Water and Organic Molecules for Electrode Materials of Rechargeable Batteries.

Science.gov (United States)

Lee, Hyeon Jeong; Shin, Jaeho; Choi, Jang Wook

2018-03-24

The intrinsic limitations of lithium-ion batteries (LIBs) with regard to safety, cost, and the availability of raw materials have promoted research on so-called "post-LIBs". The recent intense research of post-LIBs provides an invaluable lesson that existing electrode materials used in LIBs may not perform as well in post-LIBs, calling for new material designs compliant with emerging batteries based on new chemistries. One promising approach in this direction is the development of materials with intercalated water or organic molecules, as these materials demonstrate superior electrochemical performance in emerging battery systems. The enlarged ionic channel dimensions and effective shielding of the electrostatic interaction between carrier ions and the lattice host are the origins of the observed electrochemical performance. Moreover, these intercalants serve as interlayer pillars to sustain the framework for prolonged cycles. Representative examples of such intercalated materials applied to batteries based on Li + , Na + , Mg 2+ , and Zn 2+ ions and supercapacitors are considered, along with their impact in materials research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anti-tumour immune effect of oral administration of Lactobacillus plantarum to CT26 tumour-bearing mice.

Science.gov (United States)

Hu, Jingtao; Wang, Chunfeng; Ye, Liping; Yang, Wentao; Huang, Haibin; Meng, Fei; Shi, Shaohua; Ding, Zhuang

2015-06-01

Colorectal cancer (CRC) is one of the most prevalent forms of cancer that shows a high mortality and increasing incidence. There are numerous successful treatment options for CRC, including surgery, chemotherapy, radiotherapy and immunotherapy; however, their side effects and limitations are considerable. Probiotics may be an effective strategy for preventing and inhibiting tumour growth through stimulation of host innate and adaptive immunity. We investigated and compared potential anti-tumour immune responses induced by two isolated Lactobacillus strains, Lactobacillus plantarum A and Lactobacillus rhamnosus b, by pre-inoculating mice with lactobacilli for 14 days. Subsequently, subcutaneous and orthotopic intestinal tumours were generated in the pre-inoculated mice using CT26 murine adenocarcinoma cells and were assessed for response against the tumour. Our results indicated that oral administration with L. plantarum inhibited CT26 cell growth in BALB/c mice and prolonged the survival time of tumour-bearing mice compared with mice administered L. rhamnosus. L. plantarum produced protective immunity against the challenge with CT26 cells by increasing the effector functions of CD8+ and natural killer (NK) cell infiltration into tumour tissue, up-regulation of IFN-gamma (but not IL-4 or IL-17) production, and promotion of Th1-type CD4+ T differentiation. Consequently, our results suggest that L. plantarum can enhance the anti-tumour immune response and delay tumour formation.

Method for intercalating alkali metal ions into carbon electrodes

Science.gov (United States)

Doeff, Marca M.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard

1995-01-01

A low cost, relatively flexible, carbon electrode for use in a secondary battery is described. A method is provided for producing same, including intercalating alkali metal salts such as sodium and lithium into carbon.

Hydrothermal synthesis of a new ethylenediammonium intercalated ...

Indian Academy of Sciences (India)

Unknown

Vanadyl phosphate; hydrothermal synthesis; intercalation; single crystal ... presence of 'en'.7–15 In all these solids en molecules occur in suitable ... all the cases, the mixture was transferred to a 45 ml Teflon lined Parr acid digestion .... position cannot be fully occupied at the same time as it will lead to a P-P distance of.

Work Function Characterization of Potassium-Intercalated, Boron Nitride Doped Graphitic Petals

Directory of Open Access Journals (Sweden)

Patrick T. McCarthy

2017-07-01

Full Text Available This paper reports on characterization techniques for electron emission from potassium-intercalated boron nitride-modified graphitic petals (GPs. Carbon-based materials offer potentially good performance in electron emission applications owing to high thermal stability and a wide range of nanostructures that increase emission current via field enhancement. Furthermore, potassium adsorption and intercalation of carbon-based nanoscale emitters decreases work functions from approximately 4.6 eV to as low as 2.0 eV. In this study, boron nitride modifications of GPs were performed. Hexagonal boron nitride is a planar structure akin to graphene and has demonstrated useful chemical and electrical properties when embedded in graphitic layers. Photoemission induced by simulated solar excitation was employed to characterize the emitter electron energy distributions, and changes in the electron emission characteristics with respect to temperature identified annealing temperature limits. After several heating cycles, a single stable emission peak with work function of 2.8 eV was present for the intercalated GP sample up to 1,000 K. Up to 600 K, the potassium-intercalated boron nitride modified sample exhibited improved retention of potassium in the form of multiple emission peaks (1.8, 2.5, and 3.3 eV resulting in a large net electron emission relative to the unmodified graphitic sample. However, upon further heating to 1,000 K, the unmodified GP sample demonstrated better stability and higher emission current than the boron nitride modified sample. Both samples deintercalated above 1,000 K.

A naproxen complex of dysprosium intercalates into calf thymus DNA base pairs

International Nuclear Information System (INIS)

Yang, Mengsi; Jin, Jianhua; Xu, Guiqing; Cui, Fengling; Luo, Hongxia

2014-01-01

Highlights: • Binding mode to ctDNA was studied by various methods. • Intercalation is the most possible binding mode. • Dynamic and static quenching occurred simultaneously. • Hydrophobic force played a major role. • Binding characteristic of rare earth complexes to DNA are dependent on the element. - Abstract: The binding mode and mechanism of dysprosium–naproxen complex (Dy–NAP) with calf thymus deoxyribonucleic acid (ctDNA) were studied using UV–vis and fluorescence spectra in physiological buffer (pH 7.4). The results showed that more than one type of quenching process occurred and the binding mode between Dy–NAP with ctDNA might be intercalation. In addition, ionic strength, iodide quenching and fluorescence polarization experiments corroborated the intercalation binding mode between Dy–NAP and ctDNA. The calculated thermodynamic parameters ΔG, ΔH and ΔS at different temperature demonstrated that hydrophobic interaction force played a major role in the binding process

Preparation and enhanced properties of polyaniline/grafted intercalated ZnAl-LDH nanocomposites

Science.gov (United States)

Hu, Jinlong; Gan, Mengyu; Ma, Li; Zhang, Jun; Xie, Shuang; Xu, Fenfang; Shen, JiYue Zheng Xiaoyu; Yin, Hui

2015-02-01

The polymeric nanocomposites (PANI/AD-LDH) were prepared by in situ polymerization based on polyaniline (PANI) and decavanadate-intercalated and γ-aminopropyltriethoxysilane (APTS)-grafted ZnAl-layered double hydroxide (AD-LDH). FTIR and XRD studies confirm the grafting of APTS with decavanadate-intercalated LDH (D-LDH). The extent of grafting (wt%) has also been estimated on the basis of the residue left in nitrogen atmosphere at 800 °C in TGA. SEM and XPS studies show the partial exfoliation of grafted LDH in the PANI matrix and the interfacial interaction between PANI and grafted LDH, respectively. The grafted intercalated layered double hydroxide in reinforcing the properties of the PANI nanocomposites has also been investigated by open circuit potential (OCP), tafel polarization curves (TAF), electrochemical impendence spectroscopy (EIS), salt spray test and TGA-DTA. The experimental results indicate that the PANI/AD-LDH has a higher thermal stability and anticorrosion properties relative to the PANI.

Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

KAUST Repository

Cates, Nichole C.

2010-06-08

Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study of intercalation in an amorphous polymer. We study blends of the widely studied amorphous polymer poly(2-methoxy-5-(3studied amorphous polymer poly(,7·studied amorphous polymer poly(-dimethyloctyloxy)-p-phenylene vinylene) (MDMO-PPV) with a variety of molecules using photoluminescence measurements, scanning electron microscopy, and space-charge limited current mobility measurements. The blends with elevated hole mobilities exhibit complete photoluminescence quenching and show no phase separation in a scanning electron microscope. We conclude that intercalation occurs in MDMO-PPV:fullerene blends and is responsible for the increase in the MDMO-PPV hole mobility by several orders of magnitude when it is blended with fullerenes, despite the dilution of the hole-conducting polymer with an electron acceptor. © 2010 American Chemical Society.

A novel protein from the serum of Python sebae, structurally homologous with type-γ phospholipase A(2) inhibitor, displays antitumour activity.

Science.gov (United States)

Donnini, Sandra; Finetti, Federica; Francese, Simona; Boscaro, Francesca; Dani, Francesca R; Maset, Fabio; Frasson, Roberta; Palmieri, Michele; Pazzagli, Mario; De Filippis, Vincenzo; Garaci, Enrico; Ziche, Marina

2011-12-01

Cytotoxic and antitumour factors have been documented in the venom of snakes, although little information is available on the identification of cytotoxic products in snake serum. In the present study, we purified and characterized a new cytotoxic factor from serum of the non-venomous African rock python (Python sebae), endowed with antitumour activity. PSS (P. sebae serum) exerted a cytotoxic activity and reduced dose-dependently the viability of several different tumour cell lines. In a model of human squamous cell carcinoma xenograft (A431), subcutaneous injection of PSS in proximity of the tumour mass reduced the tumour volume by 20%. Fractionation of PSS by ion-exchange chromatography yielded an active protein fraction, F5, which significantly reduced tumour cell viability in vitro and, strikingly, tumour growth in vivo. F5 is composed of P1 (peak 1) and P2 subunits interacting in a 1:1 stoichiometric ratio to form a heterotetramer in equilibrium with a hexameric form, which retained biological activity only when assembled. The two peptides share sequence similarity with PIP {PLI-γ [type-γ PLA(2) (phospholipase A(2)) inhibitor] from Python reticulatus}, existing as a homohexamer. More importantly, although PIP inhibits the hydrolytic activity of PLA(2), the anti-PLA(2) function of F5 is negligible. Using high-resolution MS, we covered 87 and 97% of the sequences of P1 and P2 respectively. In conclusion, in the present study we have identified and thoroughly characterized a novel protein displaying high sequence similarity to PLI-γ and possessing remarkable cytotoxic and antitumour effects that can be exploited for potential pharmacological applications.

Isolation of high quality graphene from Ru by solution phase intercalation

Science.gov (United States)

Koren, E.; Sutter, E.; Bliznakov, S.; Ivars-Barcelo, F.; Sutter, P.

2013-09-01

We introduce a method for isolating graphene grown on epitaxial Ru(0001)/α-Al2O3. The strong graphene/Ru(0001) coupling is weakened by electrochemically driven intercalation of hydrogen underpotentially deposited in aqueous KOH solution, which allows the penetration of water molecules at the graphene/Ru(0001) interface. Following these electrochemically driven processes, the graphene can be isolated by electrochemical hydrogen evolution and transferred to arbitrary supports. Raman and transport measurements demonstrate the high quality of the transferred graphene. Our results show that intercalation, typically carried out in vacuum, can be extended to solution environments for graphene processing under ambient conditions.

Metallization and superconductivity in Ca-intercalated bilayer MoS2

Science.gov (United States)

Szczȱśniak, R.; Durajski, A. P.; Jarosik, M. W.

2017-12-01

A two-dimensional molybdenum disulfide (MoS2) has attracted significant interest recently due to its outstanding physical, chemical and optoelectronic properties. In this paper, using the first-principles calculations, the dynamical stability, electronic structure and superconducting properties of Ca-intercalated bilayer MoS2 are investigated. The calculated electron-phonon coupling constant implies that the stable form of investigated system is a strong-coupling superconductor (λ = 1.05) with a low value of critical temperature (TC = 13.3 K). Moreover, results obtained within the framework of the isotropic Migdal-Eliashberg formalism proved that Ca-intercalated bilayer MoS2 exhibits behavior that goes beyond the scope of the conventional BCS theory.

The forces that shape embryos: physical aspects of convergent extension by cell intercalation

International Nuclear Information System (INIS)

Keller, Ray; Shook, David; Skoglund, Paul

2008-01-01

We discuss the physical aspects of the morphogenic process of convergence (narrowing) and extension (lengthening) of tissues by cell intercalation. These movements, often referred to as 'convergent extension', occur in both epithelial and mesenchymal tissues during embryogenesis and organogenesis of invertebrates and vertebrates, and they play large roles in shaping the body plan during development. Our focus is on the presumptive mesodermal and neural tissues of the Xenopus (frog) embryo, tissues for which some physical measurements have been made. We discuss the physical aspects of how polarized cell motility, oriented along future tissue axes, generate the forces that drive oriented cell intercalation and how this intercalation results in convergence and extension or convergence and thickening of the tissue. Our goal is to identify aspects of these morphogenic movements for further biophysical, molecular and cell biological, and modeling studies

Crystal structures of superconducting sodium intercalates of hafnium nitride chloride

International Nuclear Information System (INIS)

Oro-Sole, J.; Frontera, C.; Beltran-Porter, D.; Lebedev, O.I.; Van Tendeloo, G.; Fuertes, A.

2006-01-01

Sodium intercalation compounds of HfNCl have been prepared at room temperature in naphtyl sodium solutions in tetrahydrofuran and their crystal structure has been investigated by Rietveld refinement using X-ray powder diffraction data and high-resolution electron microscopy. The structure of two intercalates with space group R3-bar m and lattice parameters a=3.58131(6)A, c=57.752(6)A, and a=3.58791(8)A, c=29.6785(17)A is reported, corresponding to the stages 2 and 1, respectively, of Na x HfNCl. For the stage 2 phase an ordered model is presented, showing two crystallographically independent [HfNCl] units with an alternation of the Hf-Hf interlayer distance along the c-axis, according with the occupation by sodium atoms of one out of two van der Waals gaps. Both stages 1 and 2 phases are superconducting with critical temperatures between 20 and 24K, they coexist in different samples with proportions depending on the synthesis conditions, and show a variation in c spacing that can be correlated with the sodium stoichiometry. High-resolution electron microscopy images of the host and intercalated samples show bending of the HfNCl bilayers as well as stacking faults in some regions, which coexist in the same crystal with ordered domains

Refining the molecular organization of the cardiac intercalated disc

NARCIS (Netherlands)

Vermij, Sarah H.; Abriel, Hugues; van Veen, Toon A.B.

2017-01-01

This review presents an extensively integrated model of the cardiac intercalated disc (ID), a highly orchestrated structure that connects adjacent cardiomyocytes. Classically, three main structures are distinguished: gap junctions (GJs) metabolically and electrically connect cytoplasm of adjacent

Potential-modulated intercalation of alkali cations into metal hexacyanoferrate coated electrodes. 1998 annual progress report

International Nuclear Information System (INIS)

Schwartz, D.T.

1998-01-01

'This program is studying potential-driven cation intercalation and deintercalation in metal hexacyanoferrate compounds, with the eventual goal of creating materials with high selectivity for cesium separations and long cycle lifetimes. The separation of radiocesium from other benign cations has important implications for the cost of processing a variety of cesium contaminated DOE wasteforms. This report summarizes results after nine months of work. Much of the initial efforts have been directed towards quantitatively characterizing the selectivity of nickel hexacyanoferrate derivatized electrodes for intercalating cesium preferentially over other alkali metal cations. Using energy dispersive xray spectroscopy (ex-situ, but non-destructive) and ICP analysis (ex-situ and destructive), the authors have demonstrated that the nickel hexacyanoferrate lattice has a strong preference for intercalated cesium over sodium. For example, when ions are reversibly loaded into a nickel hexacyanoferrate thin film from a solution containing 0.9999 M Na + and 0.0001 M Cs + , the film intercalates 40% as much Cs + as when loaded from pure 1 M Cs + containing electrolyte (all electrolytes use nitrates as the common anion). The authors have also shown that, contrary to the common assumptions found in the literature, a significant fraction of the thin film is not active initially. A new near infrared laser has been purchased and is being added to the Raman spectroscopy facilities to allow in-situ studies of the intercalation processes.'

Preparation of intercalated polyaniline/clay nanocomposite and its

Indian Academy of Sciences (India)

Intercalated composite of polyaniline and clay has been reported. The composite was prepared by in situ polymerization of aniline within the layers of `illite' clay. The composite was characterized for its structural, spectral, and microscopic properties. At higher level of loading the layered structure of composite breaks ...

K-intercalated carbon systems: Effects of dimensionality and substrate

KAUST Repository

Kaloni, Thaneshwor P.; Kahaly, M. Upadhyay; Cheng, Yingchun; Schwingenschlö gl, Udo

2012-01-01

the charge carrier density. Reasonably high values are found for all systems, the highest carrier density for the bilayer. The band structure and electron-phonon coupling of free-standing K-intercalated bilayer graphene points to a high probability

Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

KAUST Repository

Abou-Hamad, E; Goze-Bac, C; Nitze, F; Schmid, M; Aznar, R; Mehring, M; Wå gberg, T

2011-01-01

We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The 'metallization' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

Electronic properties of Cs-intercalated single-walled carbon nanotubes derived from nuclear magnetic resonance

KAUST Repository

Abou-Hamad, E

2011-05-24

We report on the electronic properties of Cs-intercalated single-walled carbon nanotubes (SWNTs). A detailed analysis of the 13C and 133Cs nuclear magnetic resonance (NMR) spectra reveals an increased metallization of the pristine SWNTs under Cs intercalation. The \\'metallization\\' of CsxC materials where x=0–0.144 is evidenced from the increased local electronic density of states (DOS) n(EF) at the Fermi level of the SWNTs as determined from spin–lattice relaxation measurements. In particular, there are two distinct electronic phases called α and β and the transition between these occurs around x=0.05. The electronic DOS at the Fermi level increases monotonically at low intercalation levels x<0.05 (α-phase), whereas it reaches a plateau in the range 0.05≤x≤0.143 at high intercalation levels (β-phase). The new β-phase is accompanied by a hybridization of Cs(6s) orbitals with C(sp2) orbitals of the SWNTs. In both phases, two types of metallic nanotubes are found with a low and a high local n(EF), corresponding to different local electronic band structures of the SWNTs.

Ferric chloride-graphite intercalation compounds as anode materials for Li-ion batteries.

Science.gov (United States)

Wang, Lili; Zhu, Yongchun; Guo, Cong; Zhu, Xiaobo; Liang, Jianwen; Qian, Yitai

2014-01-01

Ferric chloride-graphite intercalation compounds (FeCl3 -GICs) with stage 1 and stage 2 structures were synthesized by reacting FeCl3 and expanded graphite (EG) in air in a stainless-steel autoclave. As rechargeable Li-ion batteries, these FeCl3 -GICs exhibit high capacity, excellent cycling stability, and superior rate capability, which could be attributed to their unique intercalation features. This work may enable new possibilities for the fabrication of Li-ion batteries. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

X-ray absorption studies of graphite intercalates and metal-ammonia solutions

International Nuclear Information System (INIS)

Robertson, A.S.

1979-09-01

X-ray absorption spectroscopy (XAS) was used to study the arsenic fluorocomplexes, including the AsF 5 and AsF 6 - intercalates of graphite, and rubidium metal-ammonia solutions. The As-F distances obtained for AsF 3 and AsF 5 gas are both in excellent agreement with electron diffraction data (within 0.004 A). A superior measurement which is significantly shorter than the accepted value of the bond distance in an undistorted AsF 6 - octahedra is reported. Both the XAES and EXAFS data presented support the hypothesis that the AsF 5 oxidizes graphite upon intercalation to produce AsF 6 - and AsF 3 intercalant species. Changes in the Rb K-edge features which are consistent with the known properties of Rb-NH 3 are correlated with conductivity and delocalization of the solvated electrons. In the XAES region, intensity and position changes of absorption transitions are explained. In the EXAFS region, the Rb-N bond distance and the relative number of nitrogen atoms in the first shell are measured. XAS has been shown to provide unique information about the nature of the metal-ammonia phase separation, phase transition, and density fluctuations

α-Intercalated cells defend the urinary system from bacterial infection.

Science.gov (United States)

Paragas, Neal; Kulkarni, Ritwij; Werth, Max; Schmidt-Ott, Kai M; Forster, Catherine; Deng, Rong; Zhang, Qingyin; Singer, Eugenia; Klose, Alexander D; Shen, Tian Huai; Francis, Kevin P; Ray, Sunetra; Vijayakumar, Soundarapandian; Seward, Samuel; Bovino, Mary E; Xu, Katherine; Takabe, Yared; Amaral, Fábio E; Mohan, Sumit; Wax, Rebecca; Corbin, Kaitlyn; Sanna-Cherchi, Simone; Mori, Kiyoshi; Johnson, Lynne; Nickolas, Thomas; D'Agati, Vivette; Lin, Chyuan-Sheng; Qiu, Andong; Al-Awqati, Qais; Ratner, Adam J; Barasch, Jonathan

2014-07-01

α-Intercalated cells (A-ICs) within the collecting duct of the kidney are critical for acid-base homeostasis. Here, we have shown that A-ICs also serve as both sentinels and effectors in the defense against urinary infections. In a murine urinary tract infection model, A-ICs bound uropathogenic E. coli and responded by acidifying the urine and secreting the bacteriostatic protein lipocalin 2 (LCN2; also known as NGAL). A-IC-dependent LCN2 secretion required TLR4, as mice expressing an LPS-insensitive form of TLR4 expressed reduced levels of LCN2. The presence of LCN2 in urine was both necessary and sufficient to control the urinary tract infection through iron sequestration, even in the harsh condition of urine acidification. In mice lacking A-ICs, both urinary LCN2 and urinary acidification were reduced, and consequently bacterial clearance was limited. Together these results indicate that A-ICs, which are known to regulate acid-base metabolism, are also critical for urinary defense against pathogenic bacteria. They respond to both cystitis and pyelonephritis by delivering bacteriostatic chemical agents to the lower urinary system.

Structural, energetic and electronic properties of intercalated boron ...

Indian Academy of Sciences (India)

2National Institute for R&D of Isotopic and Molecular Technologies, Cluj-Napoca 400 293, Romania. MS received 8 November 2010; revised 28 March 2012. Abstract. The effects of chirality and the intercalation of transitional metal atoms inside single walled BN nano- tubes on structural, energetic and electronic properties ...

Pseudo Dirac dispersion in Mn-intercalated graphene on SiC

KAUST Repository

Kahaly, M. Upadhyay

2013-07-01

The atomic and electronic structures of bulk C6Mn, bulk C 8Mn, and Mn-intercalated graphene on SiC(0 0 0 1) and SiC(0001̄) are investigated by density functional theory. We find for both configurations of Mn-intercalated graphene a nonmagnetic state, in agreement with the experimental situation for SiC(0 0 0 1), and explain this property. The electronic structures around the Fermi energy are dominated by Dirac-like cones at energies consistent with data from angular resolved photoelectron spectroscopy [Gao et al., ACS Nano. 6 (2012) 6562]. However, our results demonstrate that the corresponding states trace back to hybridized Mn d orbitals, and not to the graphene. © 2013 Elsevier B.V. All rights reserved.

Pseudo Dirac dispersion in Mn-intercalated graphene on SiC

KAUST Repository

Kahaly, M. Upadhyay; Kaloni, Thaneshwor P.; Schwingenschlö gl, Udo

2013-01-01

The atomic and electronic structures of bulk C6Mn, bulk C 8Mn, and Mn-intercalated graphene on SiC(0 0 0 1) and SiC(0001̄) are investigated by density functional theory. We find for both configurations of Mn-intercalated graphene a nonmagnetic state, in agreement with the experimental situation for SiC(0 0 0 1), and explain this property. The electronic structures around the Fermi energy are dominated by Dirac-like cones at energies consistent with data from angular resolved photoelectron spectroscopy [Gao et al., ACS Nano. 6 (2012) 6562]. However, our results demonstrate that the corresponding states trace back to hybridized Mn d orbitals, and not to the graphene. © 2013 Elsevier B.V. All rights reserved.

Synthesis and characterization of a layered double hydroxide containing an intercalated nickel(II) citrate complex

International Nuclear Information System (INIS)

Wang Lianying; Wu Guoqing; Evans, David G.

2007-01-01

The nickel(II) citrate complex anion ([Ni(C 6 H 4 O 7 )] 2- ) may be intercalated into the interlayer galleries of a layered double hydroxide (LDH) host by a process involving ion-exchange with an Mg 2 Al-NO 3 LDH precursor. The powder X-ray diffraction (XRD) pattern confirms that the layered structure is maintained. The thermal decomposition process of the complex anion-intercalated material has been characterized by in situ high temperature powder XRD, thermogravimetry-differential thermal analysis (TG-DTA) and coupled with mass spectrometry (MS). The thermal stability of the nickel(II) citrate complex anion intercalated in LDHs in air is lower than that in the sodium salt. Calcination generates a high degree of nickel(II) oxide dispersion in a matrix of magnesium and aluminium oxide phases which should be an advantage if the materials are used as catalyst precursors. Based on the observed data, a structural model for the [Ni(C 6 H 4 O 7 )] 2- anion intercalated in the galleries of the LDH is proposed

Enhancement of the fluorescence intensity of DNA intercalators using nano-imprinted 2-dimensional photonic crystal

International Nuclear Information System (INIS)

Endo, Tatsuro; Ueda, China; Hisamoto, Hideaki; Kajita, Hiroshi; Okuda, Norimichi; Tanaka, Satoru

2013-01-01

We have fabricated polymer-based 2-dimensional photonic crystals that play a key role in enhancing the fluorescence of DNA intercalators. Highly ordered 2-dimensional photonic crystals possessing triangle-shaped and nm-sized hole arrays were fabricated on a 100 μm thick polymer film using nano-imprint lithography. Samples of double-stranded DNAs (sizes: 4361 and 48502 bp; concentration: 1 pM to 10 nM) were adsorbed on the surface of the 2-dimensional photonic crystal by electrostatic interactions and then treated with intercalators. It is found that the fluorescence intensity of the intercalator is enhanced by a factor of up to 10 compared to the enhancement in the absence of the 2-dimensional photonic crystal. Fluorescence intensity increases with increasing length and concentration of the DNAs. If the 2-dimensional photonic crystal is used as a Bragg reflection mirror, the enhancement of fluorescence intensity can be easily observed using a conventional spectrofluorometer. These results suggest that the printed photonic crystal offers a great potential for highly sensitive intercalator-based fluorescent detection of DNAs. (author)

Combined experimental and theoretical investigation of interactions between kaolinite inner surface and intercalated dimethyl sulfoxide

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shuai [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Liu, Qinfu, E-mail: lqf@cumtb.edu.cn [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Cheng, Hongfei [School of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing 100083 (China); Zeng, Fangui [Department of Earth Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

2015-03-15

Graphical abstract: Snapshot of the kaolinite–DMSO system after equilibrium is reached. - Highlights: • Dimethyl sulfoxide arranges a monolayer structure between kaolinite layers. • Weak hydrogen bonds exist between methyl groups of dimethyl sulfoxide and kaolinite silica layer. • Intercalated dimethyl sulfoxide forms strong hydrogen bonds with kaolinite alumina layer. - Abstract: Kaolinite intercalation complex with dimethyl sulfoxide (DMSO) was investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry–differential scanning calorimetry (TG–DSC) combined with molecular dynamics simulation. The bands assigned to the OH stretching of inner surface of kaolinite were significantly perturbed after intercalation of DMSO into kaolinite. Additionally, the bands attributed to the vibration of gibbsite-like layers of kaolinite shifted to the lower wave number, indicating that the intercalated DMSO were strongly hydrogen bonded to the alumina octahedral surface of kaolinite. The slightly decreased intensity of 1031 cm{sup −1} and 1016 cm{sup −1} band due to the in-plane vibration of Si−O of kaolinite revealed that some DMSO molecules formed weak hydrogen bonds with the silicon tetrahedral surface of kaolinite. Based on the TG result of kaolinite–DMSO intercalation complex, the formula of A1{sub 2}Si{sub 2}O{sub 5}(OH){sub 4}(DMSO){sub 0.7} was obtained, with which the kaolinite–DMSO complex model was constructed. The molecular dynamics simulation of kaolinite–DMSO complex directly confirmed the monolayer structure of DMSO in interlayer space of kaolinite, where the DMSO arranged almost parallel with kaolinite basal surface with all methyl groups being distributed near the interlayer midplane and oxygen atoms orienting toward to the alumina octahedral surface. The radial distribution function between kaolinite and intercalated DMSO verified the strong hydrogen bonds forming between hydroxyl hydrogen

Alkaline-earth metal phenylphosphonates and their intercalation chemistry

Czech Academy of Sciences Publication Activity Database

Melánová, Klára; Beneš, L.; Svoboda, J.; Zima, Vítězslav; Pospíšil, M.; Kovář, P.

2018-01-01

Roč. 47, č. 9 (2018), s. 2867-2880 ISSN 1477-9226 R&D Projects: GA ČR(CZ) GA17-10639S Institutional support: RVO:61389013 Keywords : intercalation * layered compounds * alkaline-earth metal phenylphosphonates Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.029, year: 2016

The effect of transition metals on the structure of h-BN intercalation compounds

International Nuclear Information System (INIS)

Budak, Erhan; Bozkurt, Cetin

2004-01-01

In this study, hexagonal boron nitride (h-BN) were synthesized by the modified O'Connor method in the presence of various metal nitrates [M(NO 3 ) x , M=Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ag]. The composites were analyzed by FTIR, XRF, XRD, and SEM techniques. XRD results indicated a change in the interlayer spacing due to the intercalation of Cr, Mn, Fe and Ag. SEM analyses illustrated the grain growth upon metal intercalation even at a temperature of 1320 K

Effects of Cu intercalation on the graphene/Ni(111) surface: density-functional calculations

International Nuclear Information System (INIS)

Kwon, Se Gab; Kang, Myung Ho

2012-01-01

The Cu-intercalated graphene/Ni(111) surface has been studied by using density-functional theory calculations. We find that (1) the intercalation-induced decoupling between graphene and the Ni(111) substrate begins sharply at a Cu coverage of about 0.75 ML, (2) at the optimal Cu coverage of 1 ML, graphene recovers an almost ideal Dirac-cone band structure with no band gap, and (3) the Dirac point is located at 0.17 eV below the Fermi level, indicating a small charge transfer from the substrate. Cu thus plays essentially the same role as Au in realizing quasi-free-standing graphene by intercalation. Our charge character analysis shows that the Dirac-cone bands near the Fermi level reveal a weakening of their π character when crossing the Ni d bands, suggesting that the resulting low Dirac-cone intensity could possibly be the origin of the recent photoemission report of a relatively large band gap of 0.18 eV.

Intercalation of hydrotalcites with hexacyanoferrate(II) and (III)-a thermoRaman spectroscopic study

International Nuclear Information System (INIS)

Frost, Ray L.; Musumeci, Anthony W.; Bouzaid, Jocelyn; Adebajo, Moses O.; Martens, Wayde N.; Theo Kloprogge, J.

2005-01-01

Raman spectroscopy using a hot stage indicates that the intercalation of hexacyanoferrate(II) and (III) in the interlayer space of a Mg, Al hydrotalcites leads to layered solids where the intercalated species is both hexacyanoferrate(II) and (III). Raman spectroscopy shows that depending on the oxidation state of the initial hexacyanoferrate partial oxidation and reduction takes place upon intercalation. For the hexacyanoferrate(III) some partial reduction occurs during synthesis. The symmetry of the hexacyanoferrate decreases from O h existing for the free anions to D 3d in the hexacyanoferrate interlayered hydrotalcite complexes. Hot stage Raman spectroscopy reveals the oxidation of the hexacyanoferrate(II) to hexacyanoferrate(III) in the hydrotalcite interlayer with the removal of the cyanide anions above 250 deg. C. Thermal treatment causes the loss of CN ions through the observation of a band at 2080cm -1 . The hexacyanoferrate (III) interlayered Mg, Al hydrotalcites decomposes above 150 deg. C

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

Science.gov (United States)

Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás; Kónya, Zoltán; Kukovecz, Ákos; Kristóf, János

2017-03-01

Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the 'c'-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the 'c'-crystal direction. The d(001) value showed a diffuse pattern at 7.4-7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

Science.gov (United States)

Zhamu, Aruna; Jang, Bor Z.

2014-06-17

A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

Preparation and capacitive properties of lithium manganese oxide intercalation compound

Energy Technology Data Exchange (ETDEWEB)

Tian, Fang; Xie, Yibing, E-mail: ybxie@seu.edu.cn [Southeast University, School of Chemistry and Chemical Engineering (China)

2015-12-15

Lithium manganese oxide intercalation compound (Li{sub 0.7}MnO{sub 2}) supported on titanium nitride nanotube array (TiN NTA) was applied as cathode electrode material for lithium-ion supercapacitor application. Li{sub 0.7}MnO{sub 2}/TiN NTA was fabricated through electrochemical deposition and simultaneous intercalation process using TiN NTA as a substrate, Mn(CH{sub 3}COO){sub 2} as manganese source, and Li{sub 2}SO{sub 4} as lithium source. The morphology and microstructure of the Li{sub 0.7}MnO{sub 2}/TiN NTA were characterized by scanning electron microscopy and X-ray diffraction analysis. The electrochemical performance of the Li{sub 0.7}MnO{sub 2}/TiN NTA was investigated by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge measurements. Li{sub 0.7}MnO{sub 2}/TiN NTA exhibited higher capacitive performance in Li{sub 2}SO{sub 4} electrolyte solution rather than that in Na{sub 2}SO{sub 4} electrolyte solution, which was due to the different intercalation effects of lithium-ion and sodium-ion. The specific capacitance was improved from 503.3 F g{sup −1} for MnO{sub 2}/TiN NTA to 595.0 F g{sup −1} for Li{sub 0.7}MnO{sub 2}/TiN NTA at a current density of 2 A g{sup −1} in 1.0 M Li{sub 2}SO{sub 4} electrolyte solution, which was due to the intercalation of lithium-ion for Li{sub 0.7}MnO{sub 2}. Li{sub 0.7}MnO{sub 2}/TiN NTA also kept 90.4 % capacity retention after 1000 cycles, presenting a good cycling stability. An all-solid-state lithium-ion supercapacitor was fabricated and showed an energy density of 82.5 Wh kg{sup −1} and a power density of 10.0 kW kg{sup −1}.

Intercalation of Si between MoS2 layers

Directory of Open Access Journals (Sweden)

Rik van Bremen

2017-09-01

Full Text Available We report a combined experimental and theoretical study of the growth of sub-monolayer amounts of silicon (Si on molybdenum disulfide (MoS2. At room temperature and low deposition rates we have found compelling evidence that the deposited Si atoms intercalate between the MoS2 layers. Our evidence relies on several experimental observations: (1 Upon the deposition of Si on pristine MoS2 the morphology of the surface transforms from a smooth surface to a hill-and-valley surface. The lattice constant of the hill-and-valley structure amounts to 3.16 Å, which is exactly the lattice constant of pristine MoS2. (2 The transitions from hills to valleys are not abrupt, as one would expect for epitaxial islands growing on-top of a substrate, but very gradual. (3 I(V scanning tunneling spectroscopy spectra recorded at the hills and valleys reveal no noteworthy differences. (4 Spatial maps of dI/dz reveal that the surface exhibits a uniform work function and a lattice constant of 3.16 Å. (5 X-ray photo-electron spectroscopy measurements reveal that sputtering of the MoS2/Si substrate does not lead to a decrease, but an increase of the relative Si signal. Based on these experimental observations we have to conclude that deposited Si atoms do not reside on the MoS2 surface, but rather intercalate between the MoS2 layers. Our conclusion that Si intercalates upon the deposition on MoS2 is at variance with the interpretation by Chiappe et al. (Adv. Mater. 2014, 26, 2096–2101 that silicon forms a highly strained epitaxial layer on MoS2. Finally, density functional theory calculations indicate that silicene clusters encapsulated by MoS2 are stable.

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

International Nuclear Information System (INIS)

Zsirka, Balázs; Horváth, Erzsébet; Szabó, Péter; Juzsakova, Tatjána; Szilágyi, Róbert K.; Fertig, Dávid; Makó, Éva; Varga, Tamás

2017-01-01

Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H_2O_2 and heating. • X-ray diffraction, TEM, N_2 adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N_2 adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Thin-walled nanoscrolls by multi-step intercalation from tubular halloysite-10 Å and its rearrangement upon peroxide treatment

Energy Technology Data Exchange (ETDEWEB)

Zsirka, Balázs, E-mail: zsirkab@almos.vein.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Horváth, Erzsébet, E-mail: erzsebet.horvath@gmail.com [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szabó, Péter, E-mail: xysma@msn.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Juzsakova, Tatjána, E-mail: yuzhakova@almos.uni-pannon.hu [University of Pannonia, Institute of Environmental Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Szilágyi, Róbert K., E-mail: szilagyi@montana.edu [Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717 (United States); Fertig, Dávid, E-mail: fertig.david92@gmail.com [University of Pannonia, Department of Analytical Chemistry, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Makó, Éva, E-mail: makoe@almos.vein.hu [University of Pannonia, Institute of Materials Engineering, P.O. Box 158, Veszprém 8201 Hungary (Hungary); Varga, Tamás, E-mail: vtamas@chem.u-szeged.hu [University of Szeged, Department of Applied and Environmental Chemistry, Rerrich B. tér 1., Szeged H-6720 Hungary (Hungary); and others

2017-03-31

Highlights: • Halloysite intercalation/delamination. • Thin-walled nanoscroll preparation. • Oxidative surface cleaning with H{sub 2}O{sub 2} and heating. • X-ray diffraction, TEM, N{sub 2} adsorption, TG/DTG and FT-IR/ATR measurements. • Nanoscroll rearrangement, periodicity along the crystallographic ‘c’-axis. - Abstract: Surface modification of the halloysite-10 Å mineral with tubular morphology can be achieved by slightly modified procedures developed for the delamination of kaolinite minerals. The resulting delaminated halloysite nanoparticles have unexpected surface/morphological properties that display, new potentials in catalyst development. In this work, a four-step intercalation/delamination procedure is described for the preparation of thin-walled nanoscrolls from the multi-layered hydrated halloysite mineral that consists of (1) intercalation of halloysite with potassium acetate, (2) replacement intercalation with ethylene glycol, (3) replacement intercalation with hexylamine, and (4) delamination with toluene. The intercalation steps were followed by X-ray diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption, thermogravimetry, and infrared spectroscopy. Delamination eliminated the crystalline order and the crystallite size along the ‘c’-axis, increased the specific surface area, greatly decreased the thickness of the mineral tubes to a monolayer, and shifted the pore diameter toward the micropore region. Unexpectedly, the removal of residual organics from intercalation steps adsorbed at the nanoscroll surface with a peroxide treatment resulted in partial recovery of crystallinity and increase of crystallite size along the ‘c’-crystal direction. The d(001) value showed a diffuse pattern at 7.4–7.7 Å due to the rearrangement of the thin-walled nanoscrolls toward the initial tubular morphology of the dehydrated halloysite-7 Å mineral.

Therapeutic effects of date fruits (Phoenix dactylifera) in the prevention of diseases via modulation of anti-inflammatory, anti-oxidant and anti-tumour activity.

Science.gov (United States)

Rahmani, Arshad H; Aly, Salah M; Ali, Habeeb; Babiker, Ali Y; Srikar, Sauda; Khan, Amjad A

2014-01-01

The current mode of treatment of various diseases based on synthetic drugs is expensive, alters genetic and metabolic pathways and also shows adverse side effects. Thus, safe and effective approach is needed to prevent the diseases development and progression. In this vista, Natural products are good remedy in the treatment/management of diseases and they are affordable and effective without any adverse effects. Dates are main fruit in the Arabian Peninsula and are considered to be one of the most significant commercial crops and also have been documented in Holy Quran and modern scientific literatures. Earlier studies have shown that constituents of dates act as potent antioxidant, anti-tumour as well as anti-inflammatory, provide a suitable alternative therapy in various diseases cure. In this review, dates fruits has medicinal value are summarized in terms of therapeutic implications in the diseases control through anti-oxidant, anti-inflammatory, anti-tumour and ant-diabetic effect.

Hybrid Doping of Few-Layer Graphene via a Combination of Intercalation and Surface Doping

KAUST Repository

Mansour, Ahmed

2017-05-23

Surface molecular doping of graphene has been shown to modify its work function and increase its conductivity. However, the associated shifts in work function and increases in carrier concentration are highly coupled and limited by the surface coverage of dopant molecules on graphene. Here we show that few-layer graphene (FLG) can be doped using a hybrid approach, effectively combining surface doping by larger (metal-)organic molecules, while smaller molecules, such as Br2 and FeCl3, intercalate into the bulk. Intercalation tunes the carrier concentration more effectively, whereas surface doping of intercalated FLG can be used to tune its work function without reducing the carrier mobility. This multi-modal doping approach yields a very high carrier density and tunable work function for FLG, demonstrating a new versatile platform for fabricating graphene-based contacts for electronic, optoelectronic and photovoltaic applications.

Hybrid Doping of Few-Layer Graphene via a Combination of Intercalation and Surface Doping

KAUST Repository

Mansour, Ahmed; Kirmani, Ahmad R.; Barlow, Stephen; Marder, Seth R.; Amassian, Aram

2017-01-01

Surface molecular doping of graphene has been shown to modify its work function and increase its conductivity. However, the associated shifts in work function and increases in carrier concentration are highly coupled and limited by the surface coverage of dopant molecules on graphene. Here we show that few-layer graphene (FLG) can be doped using a hybrid approach, effectively combining surface doping by larger (metal-)organic molecules, while smaller molecules, such as Br2 and FeCl3, intercalate into the bulk. Intercalation tunes the carrier concentration more effectively, whereas surface doping of intercalated FLG can be used to tune its work function without reducing the carrier mobility. This multi-modal doping approach yields a very high carrier density and tunable work function for FLG, demonstrating a new versatile platform for fabricating graphene-based contacts for electronic, optoelectronic and photovoltaic applications.

Preparation and characterization of trans-RhCl(CO)(TPPTS)2-intercalated layered double hydroxides

International Nuclear Information System (INIS)

Zhang Xian; Wei Min; Pu Min; Li Xianjun; Chen Hua; Evans, David G.; Duan Xue

2005-01-01

trans-RhCl(CO)(TPPTS) 2 (TPPTS=tris(m-sulfonatophenyl)phosphine) has been intercalated into Zn-Al layered double hydroxides (LDHs) by the method of ion exchange. The structure, composition and thermal stability of the composite material have been characterized by powder X-ray diffraction, Fourier transform infrared and 31 P solid-state magic-angle spinning nuclear magnetic resonance spectroscopy, elemental analysis, thermogravimetry, and differential thermal analysis. The geometry of trans-RhCl(CO)(TPPTS) 2 was fully optimized using the PM3 semiempirical molecular orbital method, and a schematic model for the intercalated species has been proposed. The thermal stability of trans-RhCl(CO)(TPPTS) 2 is significantly enhanced by intercalation, which suggests that such materials may have prospective application as the basis of a supported catalyst system for the hydroformylation of higher olefins

Room temperature oxidative intercalation with chalcogen hydrides: Two-step method for the formation of alkali-metal chalcogenide arrays within layered perovskites

International Nuclear Information System (INIS)

Ranmohotti, K.G. Sanjaya; Montasserasadi, M. Dariush; Choi, Jonglak; Yao, Yuan; Mohanty, Debasish; Josepha, Elisha A.; Adireddy, Shiva; Caruntu, Gabriel; Wiley, John B.

2012-01-01

Highlights: ► Topochemical reactions involving intercalation allow construction of metal chalcogenide arrays within perovskite hosts. ► Gaseous chalcogen hydrides serve as effect reactants for intercalation of sulfur and selenium. ► New compounds prepared by a two-step intercalation strategy are presented. -- Abstract: A two-step topochemical reaction strategy utilizing oxidative intercalation with gaseous chalcogen hydrides is presented. Initially, the Dion-Jacobson-type layered perovskite, RbLaNb 2 O 7 , is intercalated reductively with rubidium metal to make the Ruddlesden-Popper-type layered perovskite, Rb 2 LaNb 2 O 7 . This compound is then reacted at room-temperature with in situ generated H 2 S gas to create Rb-S layers within the perovskite host. Rietveld refinement of X-ray powder diffraction data (tetragonal, a = 3.8998(2) Å, c = 15.256(1) Å; space group P4/mmm) shows the compound to be isostructural with (Rb 2 Cl)LaNb 2 O 7 where the sulfide resides on a cubic interlayer site surrounded by rubidium ions. The mass increase seen on sulfur intercalation and the refined S site occupation factor (∼0.8) of the product indicate a higher sulfur content than expected for S 2− alone. This combined with the Raman studies, which show evidence for an H-S stretch, indicate that a significant fraction of the intercalated sulfide exists as hydrogen sulfide ion. Intercalation reactions with H 2 Se (g) were also carried out and appear to produce an isostructural selenide compound. The utilization of such gaseous hydride reagents could significantly expand multistep topochemistry to a larger number of intercalants.

Thermoelectric transport properties of polycrystalline titanium diselenide co-intercalated with nickel and titanium using spark plasma sintering

Energy Technology Data Exchange (ETDEWEB)

Holgate, T.C. [Department of Energy Storage and Conversion, Technical University of Denmark, Riso Campus, 4000 Roskilde (Denmark); Zhu, S.; Zhou, M. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Bangarigadu-Sanasy, S.; Kleinke, H. [Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); He, J. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Tritt, T.M., E-mail: ttritt@clemson.edu [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States)

2013-01-15

Polycrystalline samples of nickel intercalated (0-5%) TiSe{sub 2} were attempted via solid-state reaction in evacuated quartz tubes followed by densification using a spark plasma sintering process. X-ray diffraction data indicated that mixed NiSe{sub 2} and TiSe{sub 2} phases were present after initial synthesis by solid-state reaction, but a pure TiSe{sub 2} phase was present after the spark plasma sintering. While EPMA data reveals the stoichiometry to be near 1:1.8 (Ti:Se) for all samples, comparisons of the measured bulk densities to the theoretical densities suggest that the off stoichiometry is a result of the co-intercalation of both Ni and Ti rather than Se vacancies. Due to the presence of excess Ti (0.085-0.130 per formula) in the van der Waals gap of all the samples, the sensitive electron-hole balance is offset by the additional Ti-3d electrons, leading to an increase in the thermopower (n-type) over pristine, stoichiometric TiSe{sub 2}. The effects of the co-intercalation of both Ni and Ti in TiSe{sub 2} on the structural, thermal, and electrical properties are discussed herein. - Graphical abstract: Co-intercalation of nickel and excess titanium into the van der Waals gap of TiSe{sub 2} via solid state synthesis followed by spark plasma sintering results in a systematic shift in the ratio of hole and electron carrier concentration, which is close to unity for pristine TiSe{sub 2}. This directly affects the electrical transport properties, and as the structural disorder induced by intercalation suppresses the lattice thermal conductivity, co-intercalation is an effective route to enhance the thermoelectric properties of transition metal diselenides. Highlights: Black-Right-Pointing-Pointer Single phase bulk Ni and Ti co-intercalated TiSe{sub 2} samples prepared by spark plasma sintering. Black-Right-Pointing-Pointer Density and X-ray diffraction suggest that the Ni and excess Ti are ordered in the Van der Waals gap. Black-Right-Pointing-Pointer Co-intercalation

Lithium ion intercalation in thin crystals of hexagonal TaSe2 gated by a polymer electrolyte

Science.gov (United States)

Wu, Yueshen; Lian, Hailong; He, Jiaming; Liu, Jinyu; Wang, Shun; Xing, Hui; Mao, Zhiqiang; Liu, Ying

2018-01-01

Ionic liquid gating has been used to modify the properties of layered transition metal dichalcogenides (TMDCs), including two-dimensional (2D) crystals of TMDCs used extensively recently in the device work, which has led to observations of properties not seen in the bulk. The main effect comes from the electrostatic gating due to the strong electric field at the interface. In addition, ionic liquid gating also leads to ion intercalation when the ion size of the gate electrolyte is small compared to the interlayer spacing of TMDCs. However, the microscopic processes of ion intercalation have rarely been explored in layered TMDCs. Here, we employed a technique combining photolithography device fabrication and electrical transport measurements on the thin crystals of hexagonal TaSe2 using multiple channel devices gated by a polymer electrolyte LiClO4/Polyethylene oxide (PEO). The gate voltage and time dependent source-drain resistances of these thin crystals were used to obtain information on the intercalation process, the effect of ion intercalation, and the correlation between the ion occupation of allowed interstitial sites and the device characteristics. We found a gate voltage controlled modulation of the charge density waves and a scattering rate of charge carriers. Our work suggests that ion intercalation can be a useful tool for layered materials engineering and 2D crystal device design.

Effect of adsorbed/intercalated anionic dyes into the mechanical properties of PVA: layered zinc hydroxide nitrate nanocomposites.

Science.gov (United States)

Marangoni, Rafael; Mikowski, Alexandre; Wypych, Fernando

2010-11-15

Zinc hydroxide nitrate (ZHN) was adsorbed with anions of blue dyes (Chicago sky blue, CSB; Evans blue, EB; and Niagara blue, NB) and intercalated with anions of orange dyes (Orange G, OG; Orange II, OII; methyl orange, MO). Transparent, homogeneous and colored nanocomposite films were obtained by casting after dispersing the pigments (dye-intercalated/adsorbed into LHSs) into commercial poly(vinyl alcohol) (PVA). The films were characterized by XRD, UV-Vis spectroscopy, and mechanical testing. The mechanical properties of the PVA compounded with the dye-intercalated/adsorbed ZHN were evaluated, and reasonable increases in Young's modulus and ultimate tensile strength were observed, depending on the amount and choice of layered filler. These results demonstrate the possibility of using a new class of layered hydroxide salts intercalated and adsorbed with anionic dyes to prepare multifunctional polymer nanocomposite materials. Copyright © 2010 Elsevier Inc. All rights reserved.

An intercalated BSc degree is associated with higher marks in subsequent medical school examinations

OpenAIRE

Cleland, Jennifer A; Milne, Andrew; Sinclair, Hazel; Lee, Amanda J

2009-01-01

Abstract Background To compare medical students on a modern MBChB programme who did an optional intercalated degree with their peers who did not intercalate; in particular, to monitor performance in subsequent undergraduate degree exams. Methods This was a retrospective, observational study of anonymised databases of medical student assessment outcomes. Data were accessed for graduates, University of Aberdeen Medical School, Scotland, UK, from the years 2003 to 2007 (n = 861). The main outcom...

Synthesis, characterization and dielectric properties of polynorbornadiene–clay nanocomposites by ROMP using intercalated Ruthenium catalyst

International Nuclear Information System (INIS)

Yalçınkaya, Esra Evrim; Balcan, Mehmet; Güler, Çetin

2013-01-01

Polynorbornadiene clay nanocomposites were prepared for the first time by the ring opening metathesis polymerization (ROMP) using modified montmorillonite and polynorbornadiene the latter of which is used commonly in electric–electronic industry. The Na–MMT clay was modified by a quaternary ammonium salt containing Ruthenium complex as a suitable catalyst and intercalant as well. The norbornadiene monomers were polymerized within the modified montmorillonite layers by in-situ polymerization method in different clay loading degrees. Intercalation ability of the Ru catalyst and partially exfoliated nanocomposite structure were proved by powder X-ray Diffraction (XRD) Spectroscopy and Transmission Electron Microscopy (TEM) methods. The nanocomposite materials with high thermal degradation temperature and low dielectric constant compared to the pure polynorbornadiene were obtained. The dielectric constants decreased with the increase of the clay content. - Highlights: • Polynorbornadiene–clay nanocomposites were prepared for the first time. • Ruthenium complex was assigned as both suitable catalyst and intercalant. • The norbornadiene was polymerized by in-situ polymerization method. • Exfoliation/intercalation structures were found to be related with loading degree. • PNBD–MMT nanocomposites had a higher thermal degradation temperature and lower dielectric constant

Characterization of the response of a human breast carcinoma cell line (T-47D) to radiation and chemotherapeutic agents

International Nuclear Information System (INIS)

Prager, A.; Ben-Hur, E.; Riklis, E.

1981-01-01

The response of a human breast carcinoma cell line (T-47D) to various antitumour agents, gamma irradiation, UV light and heat was studied, using the colony-forming ability technique. Combinations of radiation with drugs and heat were also tested. The resulting survival curves corresponded to one of five patterns: simple exponential, biphasic exponential, threshold exponential, exponential plateau and ineffectual. Whereas the cells were particularly sensitive to gamma irradiation, the response to UV light was normal. The patient from whom this cell line originated did not respond to METHOTREXATEsup(R) therapy. The in vitro results correlated with this observation. (author)

Distribution of cardiac sodium channels in clusters potentiates ephaptic interactions in the intercalated disc.

Science.gov (United States)

Hichri, Echrak; Abriel, Hugues; Kucera, Jan P

2018-02-15

It has been proposed that ephaptic conduction, relying on interactions between the sodium (Na + ) current and the extracellular potential in intercalated discs, might contribute to cardiac conduction when gap junctional coupling is reduced, but this mechanism is still controversial. In intercalated discs, Na + channels form clusters near gap junction plaques, but the functional significance of these clusters has never been evaluated. In HEK cells expressing cardiac Na + channels, we show that restricting the extracellular space modulates the Na + current, as predicted by corresponding simulations accounting for ephaptic effects. In a high-resolution model of the intercalated disc, clusters of Na + channels that face each other across the intercellular cleft facilitate ephaptic impulse transmission when gap junctional coupling is reduced. Thus, our simulations reveal a functional role for the clustering of Na + channels in intercalated discs, and suggest that rearrangement of these clusters in disease may influence cardiac conduction. It has been proposed that ephaptic interactions in intercalated discs, mediated by extracellular potentials, contribute to cardiac impulse propagation when gap junctional coupling is reduced. However, experiments demonstrating ephaptic effects on the cardiac Na + current (I Na ) are scarce. Furthermore, Na + channels form clusters around gap junction plaques, but the electrophysiological significance of these clusters has never been investigated. In patch clamp experiments with HEK cells stably expressing human Na v 1.5 channels, we examined how restricting the extracellular space modulates I Na elicited by an activation protocol. In parallel, we developed a high-resolution computer model of the intercalated disc to investigate how the distribution of Na + channels influences ephaptic interactions. Approaching the HEK cells to a non-conducting obstacle always increased peak I Na at step potentials near the threshold of I Na activation

Nuclear Magnetic Resonance Study of Fluorine-Graphite Intercalation Compounds

International Nuclear Information System (INIS)

Panich, A.M.; Goren, S.D.; Nakajima, T.; Vieth, H.-M.; Privalov, A.

1998-01-01

To study the origin of semimetal-metal and metal-insulator transformations, localization effects and C-E bonding in fluorine-intercalated graphite C x F, 13 C and 19 F NMR investigations have been carried out for a wide range of fluorine content, 3.8 8, are attributed to mobile fluorine acceptor species which are responsible for the increase of electric conductivity in the dilute compound. When increasing the fluorine content to x ∼ 8 corresponding to the maximum electric conductivity, covalent C-P bonds start to oc- cur. The number of these bonds grows with fluorine content resulting in the decrease in conductivity which is caused by a percolation mechanism rather than by a change in bond length. A difference in 19 F chemical shift for fluorine-intercalated graphite C x F and covalent graphite fluoride (CF) n has been observed and is attributed to different C-P bonding in these compounds

Piezo-Electrochemical Energy Harvesting with Lithium-Intercalating Carbon Fibers.

Science.gov (United States)

Jacques, Eric; Lindbergh, Göran; Zenkert, Dan; Leijonmarck, Simon; Kjell, Maria Hellqvist

2015-07-01

The mechanical and electrochemical properties are coupled through a piezo-electrochemical effect in Li-intercalated carbon fibers. It is demonstrated that this piezo-electrochemical effect makes it possible to harvest electrical energy from mechanical work. Continuous polyacrylonitrile-based carbon fibers that can work both as electrodes for Li-ion batteries and structural reinforcement for composites materials are used in this study. Applying a tensile force to carbon fiber bundles used as Li-intercalating electrodes results in a response of the electrode potential of a few millivolts which allows, at low current densities, lithiation at higher electrode potential than delithiation. More electrical energy is thereby released from the cell at discharge than provided at charge, harvesting energy from the mechanical work of the applied force. The measured harvested specific electrical power is in the order of 1 μW/g for current densities in the order of 1 mA/g, but this has a potential of being increased significantly.

Room temperature oxidative intercalation with chalcogen hydrides: Two-step method for the formation of alkali-metal chalcogenide arrays within layered perovskites

Energy Technology Data Exchange (ETDEWEB)

Ranmohotti, K.G. Sanjaya; Montasserasadi, M. Dariush; Choi, Jonglak; Yao, Yuan; Mohanty, Debasish; Josepha, Elisha A.; Adireddy, Shiva; Caruntu, Gabriel [Department of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148-2820 (United States); Wiley, John B., E-mail: jwiley@uno.edu [Department of Chemistry and the Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148-2820 (United States)

2012-06-15

Highlights: ► Topochemical reactions involving intercalation allow construction of metal chalcogenide arrays within perovskite hosts. ► Gaseous chalcogen hydrides serve as effect reactants for intercalation of sulfur and selenium. ► New compounds prepared by a two-step intercalation strategy are presented. -- Abstract: A two-step topochemical reaction strategy utilizing oxidative intercalation with gaseous chalcogen hydrides is presented. Initially, the Dion-Jacobson-type layered perovskite, RbLaNb{sub 2}O{sub 7}, is intercalated reductively with rubidium metal to make the Ruddlesden-Popper-type layered perovskite, Rb{sub 2}LaNb{sub 2}O{sub 7}. This compound is then reacted at room-temperature with in situ generated H{sub 2}S gas to create Rb-S layers within the perovskite host. Rietveld refinement of X-ray powder diffraction data (tetragonal, a = 3.8998(2) Å, c = 15.256(1) Å; space group P4/mmm) shows the compound to be isostructural with (Rb{sub 2}Cl)LaNb{sub 2}O{sub 7} where the sulfide resides on a cubic interlayer site surrounded by rubidium ions. The mass increase seen on sulfur intercalation and the refined S site occupation factor (∼0.8) of the product indicate a higher sulfur content than expected for S{sup 2−} alone. This combined with the Raman studies, which show evidence for an H-S stretch, indicate that a significant fraction of the intercalated sulfide exists as hydrogen sulfide ion. Intercalation reactions with H{sub 2}Se{sub (g)} were also carried out and appear to produce an isostructural selenide compound. The utilization of such gaseous hydride reagents could significantly expand multistep topochemistry to a larger number of intercalants.

Selective sodium intercalation into sodium nickel-manganese sulfate for dual Na-Li-ion batteries.

Science.gov (United States)

Marinova, Delyana M; Kukeva, Rosica R; Zhecheva, Ekaterina N; Stoyanova, Radostina K

2018-04-26

Double sodium transition metal sulfates combine in themselves unique intercalation properties with eco-compatible compositions - a specific feature that makes them attractive electrode materials for lithium and sodium ion batteries. Herein, we examine the intercalation properties of novel double sodium nickel-manganese sulfate, Na2Ni1/2Mn1/2(SO4)2, having a large monoclinic unit cell, through electrochemical and ex situ diffraction and spectroscopic methods. The sulfate salt Na2Ni1/2Mn1/2(SO4)2 is prepared by thermal dehydration of the corresponding hydrate salt Na2Ni1/2Mn1/2(SO4)2·4H2O having a blödite structure. The intercalation reactions on Na2Ni1-xMnx(SO4)2 are studied in two model cells: half-ion cell versus Li metal anode and full-ion cell versus Li4Ti5O12 anode by using lithium (LiPF6 dissolved in EC/DMC) and sodium electrolytes (NaPF6 dissolved in EC:DEC). Based on ex situ XRD and TEM analysis, it is found that sodium intercalation into Na2Ni1/2Mn1/2(SO4)2 takes place via phase separation into the Ni-rich monoclinic phase and Mn-rich alluaudite phase. The redox reactions involving participation of manganese and titanium ions are monitored by ex situ EPR spectroscopy. It has been demonstrated that manganese ions from the sulfate salt are participating in the electrochemical reaction, while the nickel ions remain intact. As a result, a reversible capacity of about 65 mA h g-1 is reached. The selective intercalation properties determine sodium nickel-manganese sulfate as a new electrode material for hybrid lithium-sodium ion batteries that is thought to combine the advantages of individual lithium and sodium batteries.

High-resolution 13C nuclear magnetic resonance evidence of phase transition of Rb,Cs-intercalated single-walled nanotubes

KAUST Repository

Bouhrara, M.; Saih, Y.; Wågberg, T.; Goze-Bac, C.; Abou-Hamad, E.

2011-01-01

charge transfer is applicable at low intercalation level. The new phase at high intercalation level is accompanied by a hybridization of alkali (s) orbitals with the carbon (sp2) orbitals of the single walled nanotubes, which indicate bundle surface sites

Intercalating graphene with clusters of Fe3O4 nanocrystals for electrochemical supercapacitors

Science.gov (United States)

Ke, Qingqing; Tang, Chunhua; Liu, Yanqiong; Liu, Huajun; Wang, John

2014-04-01

A hierarchical nanostructure consisting of graphene sheets intercalated by clusters of Fe3O4 nanocystals is developed for high-performance supercapacitor electrode. Here we show that the negatively charged graphene oxide (GO) and positively charged Fe3O4 clusters enable a strong electrostatic interaction, generating a hierarchical 3D nanostructure, which gives rise to the intercalated composites through a rational hydrothermal process. The electrocapacitive behavior of the resultant composites is systematically investigated by cyclic voltammeter and galvanostatic charge-discharge techniques, where a positive synergistic effect between graphene and Fe3O4 clusters is identified. A maximum specific capacitance of 169 F g-1 is achieved in the Fe3O4 clusters decorated with effectively reduced graphene oxide (Fe3O4-rGO-12h), which is much higher than those of rGO (101 F g-1) and Fe3O4 (68 F g-1) at the current density of 1 Ag-1. Moreover, this intercalated hierarchical nanostructure demonstrates a good capacitance retention, retaining over 88% of the initial capacity after 1000 cycles.

Intercalation of a Zn(II) complex containing ciprofloxacin drug between DNA base pairs.

Science.gov (United States)

Shahabadi, Nahid; Asadian, Ali Ashraf; Mahdavi, Mryam

2017-11-02

In this study, an attempt has been made to study the interaction of a Zn(II) complex containing an antibiotic drug, ciprofloxacin, with calf thymus DNA using spectroscopic methods. It was found that Zn(II) complex could bind with DNA via intercalation mode as evidenced by: hyperchromism in UV-Vis spectrum; these spectral characteristics suggest that the Zn(II) complex interacts with DNA most likely through a mode that involves a stacking interaction between the aromatic chromophore and the base pairs of DNA. DNA binding constant (K b = 1.4 × 10 4 M -1 ) from spectrophotometric studies of the interaction of Zn(II) complex with DNA is comparable to those of some DNA intercalative polypyridyl Ru(II) complexes 1.0 -4.8 × 10 4 M -1 . CD study showed stabilization of the right-handed B form of DNA in the presence of Zn(II) complex as observed for the classical intercalator methylene blue. Thermodynamic parameters (ΔH DNA-MB, indicating that it binds to DNA in strong competition with MB for the intercalation.

The Facile Synthesis of N-Aryl Isoxazolones as DNA Intercalators ...

African Journals Online (AJOL)

NICO

2012-02-20

Feb 20, 2012 ... Chemistry Department, Islamic Azad University, Khoy Branch, Khoy, Iran. Received 9 December 2011, revised ... These compounds have potential applications as DNA intercalators. KEYWORDS. Isoxazolones ... Isoxazolones derivatives are important heterocyclic compounds with a wide range of reported ...

Antitumour and antiangiogenic activities of [Pt(O,O'-acac)(γ-acac)(DMS)] in a xenograft model of human renal cell carcinoma.

Science.gov (United States)

Muscella, A; Vetrugno, C; Biagioni, F; Calabriso, N; Calierno, M T; Fornai, F; De Pascali, S A; Marsigliante, S; Fanizzi, F P

2016-09-01

It is thought that the mechanism of action of anticancer chemotherapeutic agents is mainly due to a direct inhibition of tumour cell proliferation. In tumour specimens, the endothelial cell proliferation rate increases, suggesting that the therapeutic effects of anticancer agents could also be attributed to inhibition of tumour angiogenesis. Hence, we investigated the potential effects of [Pt(O,O'-acac)(γ-acac)(DMS)] ([Pt(DMS)]), a new platinum drug for non-genomic targets, on human renal carcinoma and compared them with those of the well-established anticancer drug, cisplatin. Tumour growth, tumour cell proliferation and microvessel density were investigated in a xenograft model of renal cell carcinoma, developed by injecting Caki-1 cells into BALB/c nude mice. The antiangiogenic potential of compounds was also investigated using HUVECs. Treatment of the Caki-1 cells with cisplatin or [Pt(DMS)] resulted in a dose-dependent inhibition of cell survival, but the cytotoxicity of [Pt(DMS)] was approximately fivefold greater than that of cisplatin. [Pt(DMS)] was much more effective than cisplatin at inhibiting tumour growth, proliferation and angiogenesis in vivo, as well as migration, tube formation and MMP1, MMP2 and MMP9 secretion of endothelial cells in vitro. Whereas, cisplatin exerted a greater cytotoxic effect on HUVECs, but did not affect tube formation or the migration of endothelial cells. In addition, treatment of the xenograft mice with [Pt(DMS)] decreased VEGF, MMP1 and MMP2 expressions in tumours. The antiangiogenic and antitumour activities of [Pt(DMS)] provide a solid starting point for its validation as a suitable candidate for further pharmacological testing. © 2016 The British Pharmacological Society.

Regenerable Cu-intercalated MnO2 layered cathode for highly cyclable energy dense batteries

Energy Technology Data Exchange (ETDEWEB)

Yadav, Gautam G.; Gallaway, Joshua W.; Turney, Damon E.; Nyce, Michael; Huang, Jinchao; Wei, Xia; Banerjee, Sanjoy

2017-03-06

Manganese dioxide cathodes are inexpensive and have high theoretical capacity (based on two electrons) of 617 mAh g-1, making them attractive for low-cost, energy-dense batteries. They are used in non-rechargeable batteries with anodes like zinc. Only ~10% of the theoretical capacity is currently accessible in rechargeable alkaline systems. Attempts to access the full capacity using additives have been unsuccessful. We report a class of Bi-birnessite (a layered manganese oxide polymorph mixed with bismuth oxide (Bi2O3)) cathodes intercalated with Cu2+ that deliver near-full two-electron capacity reversibly for >6,000 cycles. The key to rechargeability lies in exploiting the redox potentials of Cu to reversibly intercalate into the Bi-birnessite-layered structure during its dissolution and precipitation process for stabilizing and enhancing its charge transfer characteristics. This process holds promise for other applications like catalysis and intercalation of metal ions into layered structures. A large prismatic rechargeable Zn-birnessite cell delivering ~140 Wh l-1 is shown.

X-ray Spectroscopy and Imaging as Multiscale Probes of Intercalation Phenomena in Cathode Materials

Science.gov (United States)

Horrocks, Gregory A.; De Jesus, Luis R.; Andrews, Justin L.; Banerjee, Sarbajit

2017-09-01

Intercalation phenomena are at the heart of modern electrochemical energy storage. Nevertheless, as out-of-equilibrium processes involving concomitant mass and charge transport, such phenomena can be difficult to engineer in a predictive manner. The rational design of electrode architectures requires mechanistic understanding of physical phenomena spanning multiple length scales, from atomistic distortions and electron localization at individual transition metal centers to phase inhomogeneities and intercalation gradients in individual particles and concentration variances across ensembles of particles. In this review article, we discuss the importance of the electronic structure in mediating electrochemical storage and mesoscale heterogeneity. In particular, we discuss x-ray spectroscopy and imaging probes of electronic and atomistic structure as well as statistical regression methods that allow for monitoring of the evolution of the electronic structure as a function of intercalation. The layered α-phase of V2O5 is used as a model system to develop fundamental ideas on the origins of mesoscale heterogeneity.

English-language videos on YouTube as a source of information on self-administer subcutaneous anti-tumour necrosis factor agent injections.

Science.gov (United States)

Tolu, Sena; Yurdakul, Ozan Volkan; Basaran, Betul; Rezvani, Aylin

2018-05-14

The aim of this study was to evaluate the reliability, content, and quality of videos for patients available on YouTube for learning how to self-administer subcutaneous anti-tumour necrosis factor (TNF) injections. We searched for the terms Humira injection, Enbrel injection, Simponi injection, and Cimzia injection. Videos were categorised as useful information, misleading information, useful patient opinion, and misleading patient opinion by two physicians. Videos were rated for quality on a 5-point global quality scale (GQS; 1 = poor quality, 5 = excellent quality) and reliability and content using the 5-point DISCERN scale (higher scores represent greater reliability and more comprehensive videos). Of the 142 English videos, 24 (16.9%) videos were classified as useful information, 6 (4.2%) as misleading information, 47 (33.1%) as useful patient opinion, and 65 (45.8%) as misleading patient opinion. Useful videos were the most comprehensive and had the highest reliability and quality scores. The useful information and useful patient opinion videos had the highest numbers of views per day (median 8.32, IQR: 3.40-14.28 and 5.46, IQR: 3.06-14.44), as compared with 2.32, IQR: 1.63-6.26 for misleading information videos and 2.15, IQR: 1.17-7.43 for misleading patient opinion videos (p = 0.001). Almost all (91.5%) misleading videos were uploaded by individual users. There are a substantial number of English-language YouTube videos, with high quality, and rich content and reliability that can be sources of information on proper technique of anti-TNF self-injections. Physicians should direct patients to the reliable resources of information and educate them in online resource assessment, thereby improving treatment outcomes.

DNA-directed alkylating ligands as potential antitumor agents: sequence specificity of alkylation by intercalating aniline mustards.

Science.gov (United States)

Prakash, A S; Denny, W A; Gourdie, T A; Valu, K K; Woodgate, P D; Wakelin, L P

1990-10-23

The sequence preferences for alkylation of a series of novel parasubstituted aniline mustards linked to the DNA-intercalating chromophore 9-aminoacridine by an alkyl chain of variable length were studied by using procedures analogous to Maxam-Gilbert reactions. The compounds alkylate DNA at both guanine and adenine sites. For mustards linked to the acridine by a short alkyl chain through a para O- or S-link group, 5'-GT sequences are the most preferred sites at which N7-guanine alkylation occurs. For analogues with longer chain lengths, the preference of 5'-GT sequences diminishes in favor of N7-adenine alkylation at the complementary 5'-AC sequence. Magnesium ions are shown to selectively inhibit alkylation at the N7 of adenine (in the major groove) by these compounds but not the alkylation at the N3 of adenine (in the minor groove) by the antitumor antibiotic CC-1065. Effects of chromophore variation were also studied by using aniline mustards linked to quinazoline and sterically hindered tert-butyl-9-aminoacridine chromophores. The results demonstrate that in this series of DNA-directed mustards the noncovalent interactions of the carrier chromophores with DNA significantly modify the sequence selectivity of alkylation by the mustard. Relationships between the DNA alkylation patterns of these compounds and their biological activities are discussed.

Tuning metal–graphene interaction by non-metal intercalation: a case study of the graphene/oxygen/Ni (1 1 1) system

International Nuclear Information System (INIS)

Zhang, Wei-Bing; Chen, Chuan

2015-01-01

Epitaxial growth of graphene on transition metal surfaces has been proposed as one of the most promising methods for large-scale preparation of high-quality graphene. However, the presence of the substrate could significantly affect the intrinsic electronic structure of graphene and intercalation of metals is an established route for decoupling the graphene from the substrate. Taking a graphene/Ni(1 1 1) surface as an example, we suggest reactive oxygen as an effective intercalation element to recover the linear dispersion of graphene based on density functional theory calculation, in which vdW interactions are treated using the optB88-vdW functional. The possible intercalation configurations at different coverage are considered and the geometry and electronic structure are analyzed in detail. Our results indicate that the energy favorable structures change from top-fcc to bridge-top configuration after oxygen intercalation and the binding between the graphene and the O/Ni(1 1 1) substrate becomes stronger at high oxygen coverage even than pure Ni(1 1 1) substrate. Most interestingly, the electronic structure of pristine graphene is found to be almost restored, especially for the bridge-top configuration after oxygen intercalation, and the Dirac points move towards the high energy region relative to the Fermi level. A graphene/oxygen/Ni (1 1 1) system is thus suggested as a p-type doped strongly bound Dirac system. Detailed analysis using projected energy band and differential charge density indicates that the intercalated oxygen atoms react with the Ni (1 1 1) surface strongly, which not only blocks the strong interaction between Ni and graphene but also passivates oxygen 2p states. The intercalation mechanisms distinguished from the conventional metal intercalation will be useful to understand other complex intercalation systems. (paper)

Polyethylene organo-clay nanocomposites: the role of the interface chemistry on the extent of clay intercalation/exfoliation.

Science.gov (United States)

Mainil, Michaël; Alexandre, Michaël; Monteverde, Fabien; Dubois, Philippe

2006-02-01

High density polyethylene (HDPE)/clay nanocomposites have been prepared using three different functionalized polyethylene compatibilizers: an ethylene/vinyl acetate copolymer, a polyethylene grafted with maleic anhydride functions and a (styrene-b-ethylene/butylene-b-styrene) block copolymer. The nanocomposites were prepared via two different routes: (1) the dispersion in HDPE of a masterbatch prepared from the compatibilizer and the clay or (2) the direct melt blending of the three components. For each compatibilizer, essentially intercalated nanocomposites were formed as determined by X-ray diffraction and transmission electron microscopy. With the ethylene/vinyl acetate copolymer, a significant delamination of the intercalated clay in thin stacks was observed. This dispersion of thin intercalated stacks within the polymer matrix allowed increasing significantly the stiffness and the flame resistance of the nanocomposite. A positive effect of shear rate and blending time has also been put into evidence, especially for the process based on the masterbatch preparation, improving both the formation of thin stacks of intercalated clay and the mechanical properties and the flame resistance of the formed nanocomposites.

Selective blockade of B7-H3 enhances antitumour immune activity by reducing immature myeloid cells in head and neck squamous cell carcinoma.

Science.gov (United States)

Mao, Liang; Fan, Teng-Fei; Wu, Lei; Yu, Guang-Tao; Deng, Wei-Wei; Chen, Lei; Bu, Lin-Lin; Ma, Si-Rui; Liu, Bing; Bian, Yansong; Kulkarni, Ashok B; Zhang, Wen-Feng; Sun, Zhi-Jun

2017-09-01

Immature myeloid cells including myeloid-derived suppressor cells (MDSCs) and tumour-associated macrophages (TAMs) promote tumour growth and metastasis by facilitating tumour transformation and angiogenesis, as well as by suppressing antitumour effector immune responses. Therefore, strategies designed to reduce MDSCs and TAMs accumulation and their activities are potentially valuable therapeutic goals. In this study, we show that negative immune checkpoint molecule B7-H3 is significantly overexpressed in human head and neck squamous cell carcinoma (HNSCC) specimen as compared with normal oral mucosa. Using immunocompetent transgenic HNSCC models, we observed that targeting inhibition of B7-H3 reduced tumour size. Flow cytometry analysis revealed that targeting inhibition of B7-H3 increases antitumour immune response by decreasing immunosuppressive cells and promoting cytotoxic T cell activation in both tumour microenvironment and macroenvironment. Our study provides direct in vivo evidence for a rationale for B7-H3 blockade as a future therapeutic strategy to treat patients with HNSCC. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Anti-Tumour Promoting Activity and Antioxidant Properties of Girinimbine Isolated from the Stem Bark of Murraya koenigii S.

Directory of Open Access Journals (Sweden)

Yih Yih Kok

2012-04-01

Full Text Available Girinimbine, a carbazole alkaloid isolated from the stem bark of Murraya koenigii was tested for the in vitro anti-tumour promoting and antioxidant activities. Anti-tumour promoting activity was determined by assaying the capability of this compound to inhibit the expression of early antigen of Epstein-Barr virus (EA-EBV in Raji cells that was induced by the tumour promoter, phorbol 12-myristate 13-acetate. The concentration of this compound that gave an inhibition rate at fifty percent was 6.0 µg/mL and was not cytotoxic to the cells. Immunoblotting analysis of the expression of EA-EBV showed that girinimbine was able to suppress restricted early antigen (EA-R. However, diffused early antigen (EA-D was partially suppressed when used at 32.0 µg/mL. Girinimbine exhibited a very strong antioxidant activity as compared to a-tocopherol and was able to inhibit superoxide generation in the 12-O-tetradecanoylphorbol-13-acetate (TPA-induced differentiated premyelocytic HL-60 cells more than 95%, when treated with the compound at 5.3 and 26.3 µg/mL, respectively. However girinimbine failed to scavenge the stable diphenyl picryl hydrazyl (DPPH-free radical.

Intercalation of Mg-ions in layered V2O5 cathode materials for rechargeable Mg-ion batteries

DEFF Research Database (Denmark)

Sørensen, Daniel Risskov; Johannesen, Pætur; Christensen, Christian Kolle

The development of functioning rechargeable Mg-ion batteries is still in its early stage, and a coarse screening of suitable cathode materials is still on-going. Within the intercalation-type cathodes, layered crystalline materials are of high interest as they are known to perform well in Li-ion...... intercalation batteries and are also increasingly being explored for Na-ion batteries. Here, we present an investigation of the layered material orthorhombic V2O5, which is a classical candidate for an ion-intercalation material having a high theoretical capacity1. We present discharge-curves for the insertion...... discharge. This indicates that the degradation is highly associated with formation of ion-blocking layers on the anode....

Classical molecular dynamics and quantum abs-initio studies on lithium-intercalation in interconnected hollow spherical nano-spheres of amorphous Silicon

DEFF Research Database (Denmark)

Bhowmik, Arghya; Malik, R.; Prakash, S.

2016-01-01

A high concentration of lithium, corresponding to charge capacity of ~4200 mAh/g, can be intercalated in silicon. Unfortunately, due to high intercalation strain leading to fracture and consequent poor cyclability, silicon cannot be used as anode in lithium ion batteries. But recently interconnec......A high concentration of lithium, corresponding to charge capacity of ~4200 mAh/g, can be intercalated in silicon. Unfortunately, due to high intercalation strain leading to fracture and consequent poor cyclability, silicon cannot be used as anode in lithium ion batteries. But recently...... interconnected hollow nano-spheres of amorphous silicon have been found to exhibit high cyclability. The absence of fracture upon lithiation and the high cyclability has been attributed to reduction in intercalation stress due to hollow spherical geometry of the silicon nano-particles. The present work argues...... that the hollow spherical geometry alone cannot ensure the absence of fracture. Using classical molecular dynamics and density functional theory based simulations; satisfactory explanation to the absence of fracture has been explored at the atomic scale....

Thermally Induced Lateral Motion of α-Zirconium Phosphate Layers Intercalated with Hexadecylamines

Science.gov (United States)

Char, Kookheon

2005-03-01

Well-defined intercalated structure, either interdigitated layers or bilayers, of hexadecylamines (HDAs) in a confined space of a highly-functionalized layered material, α- zirconium phosphate (α-ZrP), was prepared and these two distinct intercalated structures can serve as model systems to investigate the interaction of the two monolayers whose amphiphilic tails are adjacent to each other. Acidic functional groups (-POH) on the α-ZrP are in well-ordered array and the number of functional group is quite high (i.e., cationic exchange capacity (CEC) = 664 mmole/100 g, area per one charge site = 0.24 nm^2) enough to realize the bilayers (i.e., discrete two monolayers) of HDAs within the α-ZrP interlayer. We employed the two-step intercalation mechanism for the preparation of well- ordered interdigitated layers as well as the bilayers of alkyl chains attached to both sides of the α-ZrP intergallery. An intriguing lateral motion of the α-ZrP sheets was observed with in-situ SAXS measurements for the interdigitated layer during heating and cooling cycle and verified with TEM. This lateral motion is believed to be due to the transition from the tilted to the untilted conformation of the interdigitated HDA chains and this transition is found to be thermally reversible.

Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids - TINA

DEFF Research Database (Denmark)

Schneider, Uffe V; Géci, Imrich; Jøhnk, Nina

2011-01-01

-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5' and 3' termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved......The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators....... Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para...

Intercalation of alcohols into barium phenylphosphonate: Influence of the number and position of funcitonal groups in the guests on their arrangement in the intercalates.

Czech Academy of Sciences Publication Activity Database

Melánová, Klára; Beneš, L.; Zima, Vítězslav; Svoboda, J.; Růžička, A.

2017-01-01

Roč. 251, July (2017), s. 211-216 ISSN 0022-4596 R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : intercalation * barium phosphonate * alcohol s Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 2.299, year: 2016

Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

International Nuclear Information System (INIS)

Cursino, Ana Cristina Trindade; Rives, Vicente; Arizaga, Gregorio Guadalupe Carbajal; Trujillano, Raquel; Wypych, Fernando

2015-01-01

Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials

Rare earth and zinc layered hydroxide salts intercalated with the 2-aminobenzoate anion as organic luminescent sensitizer

Energy Technology Data Exchange (ETDEWEB)

Cursino, Ana Cristina Trindade, E-mail: anacursino@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Rives, Vicente, E-mail: vrives@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Arizaga, Gregorio Guadalupe Carbajal, E-mail: gregoriocarbajal@yahoo.com.mx [Universidad de Guadalajara, Department of Chemistry, Boulevard Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Trujillano, Raquel, E-mail: rakel@usal.es [GIR-QUESCAT – Department of Inorganic Chemistry, Universidad de Salamanca, Plaza de la Merced S/N, 37998 Salamanca (Spain); Wypych, Fernando, E-mail: wypych@ufpr.br [CEPESQ – Research Centre of Applied Chemistry, Department of Chemistry, Universidade Federal do Paraná – P.O. Box 19081, 81531-980 Curitiba, PR (Brazil)

2015-10-15

Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The UV absorption ability was improved after intercalation/grafting in relation to that shown by the parent material. - Highlights: • Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide were synthesized. • Intercalated nitrate anions were exchanged by 2-aminobenzoate. • In all the 2-aminobenzoate containing compounds, the grafting reaction was detected. • The UV absorption ability was improved after the exchange reactions. • Rare earth hydroxide salts are potential matrixes to produce luminescent materials. - Abstract: Rare earth (RE = Eu, Y and Tb) and zinc layered hydroxide salts intercalated with nitrate anions were synthesized, followed by exchange with 2-aminobenzoate. The obtained compounds were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and ultraviolet visible (UV–vis) spectroscopies, fluorescence measurements and thermal analysis (TGA/DTA). The results from FTIR spectroscopy suggest a direct coordination of 2-aminobenzoate to the metal cations of the inorganic layered structure. The organic derivative products from the intercalation reactions absorb a broader range of UV-light in relation to that shown by the parent material; the photoluminescence measurements present a strong violet, blue and green luminescence under UV-light excitation for layered compounds with, Zn, Y and Tb, respectively. Rare earth hydroxide salts (RE-LHS) are potential alternative matrices for the immobilization of organic species to produce luminescent materials.

Synthesis, characterization, and controlled release antibacterial behavior of antibiotic intercalated Mg–Al layered double hydroxides

International Nuclear Information System (INIS)

Wang, Yi; Zhang, Dun

2012-01-01

Graphical abstract: The antibiotic anion released from Mg–Al LDHs provides a controlled release antibacterial activity against the growth of Micrococcus lysodeikticus in 3.5% NaCl solution. Highlights: ► Antibiotic anion intercalated LDHs were synthesized and characterized. ► The ion-exchange one is responsible for the release process. ► The diffusion through particle is the release rate limiting step. ► LDHs loaded with antibiotic anion have high antibacterial capabilities. -- Abstract: Antibiotic–inorganic clay composites including four antibiotic anions, namely, benzoate (BZ), succinate (SU), benzylpenicillin (BP), and ticarcillin (TC) anions, intercalated Mg–Al layered double hydroxides (LDHs) were synthesized via ion-exchange. Powder X-ray diffraction and Fourier transform infrared spectrum analyses showed the successful intercalation of antibiotic anion into the LDH interlayer. BZ and BP anions were accommodated in the interlayer region as a bilayer, whereas SU and TC anions were intercalated in a monolayer arrangement. Kinetic simulation of the release data indicated that ion-exchange was responsible for the release process, and the diffusion through the particles was the rate-limiting step. The antibacterial capabilities of LDHs loaded with antibiotic anion toward Micrococcus lysodeikticus growth were analyzed using a turbidimetric method. Significant high inhibition rate was observed when LDH nanohybrid was introduced in 3.5% NaCl solution. Therefore, this hybrid material may be applied as nanocontainer in active antifouling coating for marine equipment.

Intercalation compounds of vanadium(5) phosphates with glycerol

International Nuclear Information System (INIS)

Yakovleva, T.N.; Vykhodtseva, K.I.; Tarasova, D.V.; Soderzhinova, M.M.

1997-01-01

Interaction products of glycerol aqueous solutions with vanadium(5) phosphates were investigated by the methods of ESR, X-ray phase and thermal analyses. It is shown that glycerol molecules enter the interlayer space of VOPO 4 · 2H 2 O lattice with formation of disordered intercalated compounds with glycerol on the basis of partially reduced vanadium phosphate form when using α-VOPO 4 . 16 refs., 4 figs., 1 tab

Ion transport and phase transformation in thin film intercalation electrodes

Energy Technology Data Exchange (ETDEWEB)

Wunde, Fabian; Nowak, Susann; Muerter, Juliane; Hadjixenophontos, Efi; Berkemeier, Frank; Schmitz, Guido [Stuttgart Univ. (Germany). Inst. fuer Materialwissenschaft

2017-11-15

Thin film battery electrodes of the olivine structure LiFePO{sub 4} and the spinel phase LiMn{sub 2}O{sub 4} are deposited through ion-beam sputtering. The intercalation kinetics is studied by cyclo-voltammetry using variation of the cycling rate over 4 to 5 orders of magnitude. The well-defined layer geometry allows a detailed quantitative analysis. It is shown that LiFePO{sub 4} clearly undergoes phase separation during intercalation, although the material is nano-confined and very high charging rates are applied. We present a modified Randles-Sevcik evaluation adapted to phase-separating systems. Both the charging current and the overpotential depend on the film thickness in a systematic way. The analysis yields evidence that the grain boundaries are important short circuit paths for fast transport. They increase the electrochemical active area with increasing layer thickness. Evidence is obtained that the grain boundaries in LiFePO{sub 4} have the character of an ion-conductor of vanishing electronic conductivity.

Origin of the high p-doping in F intercalated graphene on SiC

KAUST Repository

Cheng, Yingchun

2011-08-04

The atomic and electronic structures of F intercalated epitaxialgraphene on a SiC(0001) substrate are studied by first-principles calculations. A three-step fluorination process is proposed. First, F atoms are intercalated between the graphene and the SiC, which restores the Dirac point in the band structure. Second, saturation of the topmost Si dangling bonds introduces p-doping up to 0.37 eV. Third, F atoms bond covalently to the graphene to enhance the p-doping. Our model explains the highly p-doped state of graphene on SiC after fluorination [A. L. Walter et al., Appl. Phys. Lett. 98, 184102 (2011)].

Oscillatory behaviors and hierarchical assembly of contractile structures in intercalating cells

International Nuclear Information System (INIS)

Fernandez-Gonzalez, Rodrigo; Zallen, Jennifer A

2011-01-01

Fluctuations in the size of the apical cell surface have been associated with apical constriction and tissue invagination. However, it is currently not known if apical oscillatory behaviors are a unique property of constricting cells or if they constitute a universal feature of the force balance between cells in multicellular tissues. Here, we set out to determine whether oscillatory cell behaviors occur in parallel with cell intercalation during the morphogenetic process of axis elongation in the Drosophila embryo. We applied multi-color, time-lapse imaging of living embryos and SIESTA, an integrated tool for automated and semi-automated cell segmentation, tracking, and analysis of image sequences. Using SIESTA, we identified cycles of contraction and expansion of the apical surface in intercalating cells and characterized them at the molecular, cellular, and tissue scales. We demonstrate that apical oscillations are anisotropic, and this anisotropy depends on the presence of intact cell–cell junctions and spatial cues provided by the anterior–posterior patterning system. Oscillatory cell behaviors during axis elongation are associated with the hierarchical assembly and disassembly of contractile actomyosin structures at the medial cortex of the cell, with actin localization preceding myosin II and with the localization of both proteins preceding changes in cell shape. We discuss models to explain how the architecture of cytoskeletal networks regulates their contractile behavior and the mechanisms that give rise to oscillatory cell behaviors in intercalating cells

Molecular Simulation Models of Carbon Dioxide Intercalation in Hydrated Sodium Montmorillonite

Energy Technology Data Exchange (ETDEWEB)

Myshakin, Evgeniy [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Saidi, Wissam [Univ. of Pittsburgh, PA (United States); Romanov, Vyacheslav [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Cygan, Randall [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jordan, Kenneth [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Univ. of Pittsburgh, PA (United States); Guthrie, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-11-22

In this study, classical molecular dynamics simulations and density functional theory (DFT)-based molecular dynamics are used to elucidate the process of CO₂ intercalation into hydrated Na-montmorillonite at P-T conditions relevant to geological formations suitable for CO₂ storage. Of particular interest are the structural and transport properties of interlayer species after CO₂ intercalation. The conducted simulations allowed the research team to quantify expansion/contraction of smectite as a function of CO₂ and H₂O compositions. The resulting swelling curves can be used to gauge the amount of stored CO₂, compare it to the experiment, and estimate changes in geomechanical properties of the storage formation. The obtained results showed that the infrared signal of the asymmetric stretch vibration of CO₂ molecule is extremely sensitive to the solvent environment. The extent of the frequency shift relative to the gas-phase value can be used to probe hydration level in the interlayer with intercalated CO₂. Interaction of supercritical CO₂ with brine in deep geological formations promotes an increase of hydrophobicity of clay surfaces. As a result of wettability alteration, estimated diffusion constants of CO₂ and H₂O increase with the increased CO₂ load; this can contribute to faster migration of CO₂ throughout the formation.

Resistivity features in intercalated graphite compounds with bromine and iodine chloride in the region of structural phase transitions in the layer of intercalate

International Nuclear Information System (INIS)

Ovsyijenko, Yi.V.; Lazarenko, O.A.; Matsuj, L.Yu.; Prokopov, O.Yi.

2013-01-01

In the paper anomalous changes of resistivity in graphite intercalated compounds with iodine chloride and bromine are investigated in the phase transition temperature interval. It is shown that these anomalies are caused by the change of carriers mobility in the phase transitional interval as well as by the origin of ''mobile ions liquids''

Optical contrast spectra studies for determining thickness of stage-1 graphene-FeCl{sub 3} intercalation compounds

Energy Technology Data Exchange (ETDEWEB)

Han, Wen-Peng, E-mail: han-wenpeng@163.com, E-mail: yunze.long@163.com; Yan, Xu; Zhao, Hui [College of Physics, Qingdao University, Qingdao 266071 (China); Li, Qiao-Qiao; Lu, Yan [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Long, Yun-Ze, E-mail: han-wenpeng@163.com, E-mail: yunze.long@163.com [College of Physics, Qingdao University, Qingdao 266071 (China); Collaborative Innovation Center for Low-Dimensional Nanomaterials and Optoelectronic Devices, Qingdao University, Qingdao 266071 (China)

2016-07-15

Because of novel features in their structural, electronic, magnetic and optical properties, especially potential applications in nanoelectronics, the few-layer graphene intercalation compounds (FLGICs) have been intensively studied recently. In this work, the dielectric constant of the doped graphene of stage-1 FeCl{sub 3}-GIC is obtained by fitting the optical contrast spectra. And fully intercalated stage-1 FeCl{sub 3}-FLGICs were prepared by micromechanical cleavage method from graphite intercalation compounds (GICs) for the first time. Finally, we demonstrated that the thickness of stage-1 FeCl{sub 3}-GICs by micromechanical cleavage can be determined by optical contrast spectra. This method also can be used to other FLGICs, such as SbCl{sub 5}-FLGICs and AuCl{sub 5}-FLGICs, etc.

Reversible intercalation of ammonia molecules into a layered double hydroxide structure without exchanging nitrate counter-ions

International Nuclear Information System (INIS)

Carbajal Arizaga, Gregorio Guadalupe; Wypych, Fernando; Castillon Barraza, Felipe; Contreras Lopez, Oscar Edel

2010-01-01

A zinc/aluminum LDH was precipitated with recycled ammonia from a chemical vapor deposition reaction. The LDH presented a crystalline phase with basal distance of 8.9 A, typical for nitrate-containing LDHs, and another phase with a basal distance of 13.9 A. Thermal treatment at 150 o C eliminated the phase with the bigger basal distance leaving only the anhydrous nitrate-intercalated LDH structure with 8.9 A. Intense N-H stretching modes in the FTIR spectra suggested that the expansion was due to intercalation of ammonia in the form of [NH 4 (NH 3 ) n ] + species. When additional samples were precipitated with pure ammonia, the conventional LDH nitrate structure was obtained (8.9 A basal distance) at pH=7, as well as a pure crystalline phase with 13.9 A basal distance at pH=10 due to ammonia intercalation that can be removed by heating at 150 o C or by stirring in acetone, confirming a unusual sensu stricto intercalation process into a LDH without exchanging nitrate ions. - Graphical abstract: LDH-nitrate precipitated with ammonia expands the interlayer space if ammonia is bubbled up to pH 10. The basal distance decreased when the compound was heated at 150 o C or stirred in acetone. Nitrate ions are not exchanged.

Synthesis and characterization of intercalated polyaniline-clay nanocomposite using supercritical CO2

Science.gov (United States)

Abdelraheem, A.; El-Shazly, A. H.; Elkady, M. F.

2018-05-01

Lately, supercritical CO2 (SCCO2) have been getting great interest. It can be used in numerous applications because it is environmentally friendly, safe, comparatively low cost, and nonflammable. One of its applications is being a solvent in the synthesis of polymeric-clay nanocomposite. In this paper, intercalated polyaniline-clay nanocomposite (PANC) was prepared using SCCO2. The intercalation structure of polyaniline chains between clay layers was verified by various characterization techniques. Scanning electron microscope and transmission electron microscope (SEM-TEM) were used to show the morphology of the synthesized nanocomposite. The molecular structure of PANC nanocomposite was confirmed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The BET surface area and the conductivity of the nanocomposite were determined.

High surface area V-Mo-N materials synthesized from amine intercalated foams

International Nuclear Information System (INIS)

Krawiec, Piotr; Narayan Panda, Rabi; Kockrick, Emanuel; Geiger, Dorin; Kaskel, Stefan

2008-01-01

Nanocrystalline ternary V-Mo nitrides were prepared via nitridation of amine intercalated oxide foams or bulk ternary oxides. Specific surface areas were in the range between 40 and 198 m 2 g -1 and strongly depended on the preparation method (foam or bulk oxide). Foamed precursors were favorable for vanadium rich materials, while for molybdenum rich samples bulk ternary oxides resulted in higher specific surface areas. The materials were characterized via nitrogen physisorption at 77 K, X-ray diffraction patterns, electron microscopy, and elemental analysis. - Graphical abstract: Nanocrystalline ternary V-Mo nitrides were prepared via nitridation of amine intercalated oxide foams or bulk ternary oxides. Foamed precursors were favorable for vanadium rich materials, while for molybdenum rich samples bulk ternary oxides resulted in higher specific surface areas

Antitumour Activity of the Microencapsulation of Annona vepretorum Essential Oil.

Science.gov (United States)

Bomfim, Larissa M; Menezes, Leociley R A; Rodrigues, Ana Carolina B C; Dias, Rosane B; Rocha, Clarissa A Gurgel; Soares, Milena B P; Neto, Albertino F S; Nascimento, Magaly P; Campos, Adriana F; Silva, Lidércia C R C E; Costa, Emmanoel V; Bezerra, Daniel P

2016-03-01

Annona vepretorum Mart. (Annonaceae), popularly known as 'bruteira', has nutritional and medicinal uses. This study investigated the chemical composition and antitumour potential of the essential oil of A. vepretorum leaf alone and complexed with β-cyclodextrin in a microencapsulation. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus and analysed using GC-MS and GC-FID. In vitro cytotoxicity of the essential oil and some of its major constituents in tumour cell lines from different histotypes was evaluated using the alamar blue assay. Furthermore, the in vivo efficacy of essential oil was demonstrated in mice inoculated with B16-F10 mouse melanoma. The essential oil included bicyclogermacrene (35.71%), spathulenol (18.89%), (E)-β-ocimene (12.46%), α-phellandrene (8.08%), o-cymene (6.24%), germacrene D (3.27%) and α-pinene (2.18%) as major constituents. The essential oil and spathulenol exhibited promising cytotoxicity. In vivo tumour growth was inhibited by the treatment with the essential oil (inhibition of 34.46%). Importantly, microencapsulation of the essential oil increased in vivo tumour growth inhibition (inhibition of 62.66%). © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Tuning Fullerene Intercalation in a Poly (thiophene) derivative by Controlling the Polymer Degree of Self-Organisation

Science.gov (United States)

Paternò, G. M.; Skoda, M. W. A.; Dalgliesh, Robert; Cacialli, F.; Sakai, V. García

2016-10-01

Controlling the nanoscale arrangement in polymer-fullerene organic solar cells is of paramount importance to boost the performance of such promising class of photovoltaic diodes. In this work, we use a pseudo-bilayer system made of poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), to acquire a more complete understanding of the diffusion and intercalation of the fullerene-derivative within the polymer layer. By exploiting morphological and structural characterisation techniques, we observe that if we increase the film solidification time the polymer develops a higher crystalline order, and, as a result, it does not allow fullerene molecules to intercalate between the polymer side-chains. Gaining insight into the detailed fullerene intercalation mechanism is important for the development of organic photovoltaic diodes (PVDs).

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound.

Science.gov (United States)

Abdul Latip, Ahmad Faiz; Hussein, Mohd Zobir; Stanslas, Johnson; Wong, Charng Choon; Adnan, Rohana

2013-01-01

Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems.

Tunable Broadband Nanocarbon Transparent Conductor by Electrochemical Intercalation.

Science.gov (United States)

Wan, Jiayu; Xu, Yue; Ozdemir, Burak; Xu, Lisha; Sushkov, Andrei B; Yang, Zhi; Yang, Bao; Drew, Dennis; Barone, Veronica; Hu, Liangbing

2017-01-24

Optical transparent and electrical conducting materials with broadband transmission are important for many applications in optoelectronic, telecommunications, and military devices. However, studies of broadband transparent conductors and their controlled modulation are scarce. In this study, we report that reversible transmittance modulation has been achieved with sandwiched nanocarbon thin films (containing carbon nanotubes (CNTs) and reduced graphene oxide (rGO)) via electrochemical alkali-ion intercalation/deintercalation. The transmittance modulation covers a broad range from the visible (450 nm) to the infrared (5 μm), which can be achieved only by rGO rather than pristine graphene films. The large broadband transmittance modulation is understood with DFT calculations, which suggest a decrease in interband transitions in the visible range as well as a reduced reflection in the IR range upon intercalation. We find that a larger interlayer distance in few-layer rGO results in a significant increase in transparency in the infrared region of the spectrum, in agreement with experimental results. Furthermore, a reduced plasma frequency in rGO compared to few-layer graphene is also important to understand the experimental results for broadband transparency in rGO. The broadband transmittance modulation of the CNT/rGO/CNT systems can potentially lead to electrochromic and thermal camouflage applications.

Preparation of an anionic azo pigment-pillared layered double hydroxide and the thermo- and photostability of the resulting intercalated material

Science.gov (United States)

Guo, Shengchang; Li, Dianqing; Zhang, Weifeng; Pu, Min; Evans, David G.; Duan, Xue

2004-12-01

A large anionic pigment has been intercalated into a layered double hydroxide (LDH) host by ion-exchange of an Mg/Al LDH-nitrate precursor with a solution of C.I. Pigment Red 48:2 (the calcium salt of 4-((5-chloro-4-methyl-2-sulfophenyl)azo)-3-hydroxy-2-naphthalene-carboxylic acid), in ethane-1,2-diol. After intercalation of the pigment, the interlayer distance in the LDH increases from 0.86 to 1.72 nm. Infrared spectra and TG-DTA curves reveal the presence of a complex system of supramolecular host-guest interactions. The UV-visible diffuse reflectance spectra of C.I. Pigment Red 48:2 show marked changes after heating at 200 °C and above, whereas there are no significant changes in the spectra of the intercalated pigment after heating at temperatures up to 300 °C, showing that the thermostability is markedly enhanced by intercalation in the LDH host. The pigment-intercalated LDHs exhibits much higher photostability to UV light than the pristine pigment, in the case of both the pure solids and their composites with polypropylene, as shown by measurement of CIE 1976 L*a*b* color difference ( ΔE) values.

Inhibition of translation in liver polyribosomes by a new substituted thiopseudourea with antitumour action

Science.gov (United States)

González-Cadavid, Néstor F.; Quijada, Flor Herrera

1974-01-01

A new thiopseudourea, S-(10-undecen-1-yl)isothiouronium iodide (compound AHR-1911), was tested for antitumour action and shown to inhibit considerably the growth of the Walker carcinoma in rats. The mechanism of its effect on protein and nucleic acid synthesis was then studied with systems in vitro from rat liver. In incubations of liver slices, 1.4mm-compound AHR-1911 decreased by 96% the incorporation of [14C]leucine into microsomal proteins, and mitochondrial protein synthesis measured in the presence of cycloheximide was decreased by 44%. At lower doses, translation, as well as the incorporation of [3H]uridine into RNA, was also considerably impaired, compound AHR-1911 being the most active of all the thiopseudoureas tested whereas undecylenic acid and thiourea by themselves showed practically no inhibition. Protein synthesis by cytoplasmic ribosomes (microsomes and C-polyribosomes) was inhibited by compound AHR-1911 at different concentrations (72% at 0.42mm), and again the other related compounds were much less effective, with the exception of one antileukaemic thiopseudourea. The same occurred with the poly(U)-stimulated incorporation of phenylalanine. The puromycin reaction with pulse-labelled C-ribosomes was strongly inhibited, particularly when preincubation with compound AHR-1911 preceded the addition of puromycin, with no release of nascent chains by the thiopseudourea alone. In the presence of GTP and pH5 fraction, to induce translocation and transform all the ribosomes to the donor state, the percentage inhibition remained the same. The ribosomes incubated with the drug are aggregated, as shown by the polyribosome profile, but, when excess of inhibitor was removed, the activity in protein synthesis and the puromycin reaction was restored, indicating that the inhibition is not due to the polyribosomal aggregation. These results suggest that the effect on translation with both 55S and 80S ribosomes is derived from inhibition of chain elongation at the

Synergy of irofulven in combination with other DNA damaging agents: synergistic interaction with altretamine, alkylating, and platinum-derived agents in the MV522 lung tumor model.

Science.gov (United States)

Kelner, Michael J; McMorris, Trevor C; Rojas, Rafael J; Estes, Leita A; Suthipinijtham, Pharnuk

2008-12-01

Irofulven (MGI 114, NSC 683863) is a semisynthetic derivative of illudin S, a natural product present in the Omphalotus illudins (Jack O'Lantern) mushroom. This novel agent produces DNA damage, that in contrast to other agents, is predominately ignored by the global genome repair pathway of the nucleotide excision repair (NER)(2) system. The aim of this study was to determine the antitumor activity of irofulven when administered in combination with 44 different DNA damaging agents, whose damage is in general detected and repaired by the genome repair pathway. The human lung carcinoma MV522 cell line and its corresponding xenograft model were used to evaluate the activity of irofulven in combination with different DNA damaging agents. Two main classes of DNA damaging agents, platinum-derived agents, and select bifunctional alkylating agents, demonstrated in vivo synergistic or super-additive interaction with irofulven. DNA helicase inhibiting agents also demonstrated synergy in vitro, but an enhanced interaction with irofulven could not be demonstrated in vivo. There was no detectable synergistic activity between irofulven and agents capable of inducing DNA cleavage or intercalating into DNA. These results indicate that the antitumor activity of irofulven is enhanced when combined with platinum-derived agents, altretamine, and select alkylating agents such as melphalan or chlorambucil. A common factor between these agents appears to be the production of intrastrand DNA crosslinks. The synergistic interaction between irofulven and other agents may stem from the nucleotide excision repair system being selectively overwhelmed at two distinct points in the pathway, resulting in prolonged stalling of transcription forks, and subsequent initiation of apoptosis.

Preparation of 5-benzotriazolyl-4-hydroxy-3-sec-butylbenzenesulfonate anion-intercalated layered double hydroxide and its photostabilizing effect on polypropylene

International Nuclear Information System (INIS)

Li Dianqing; Tuo Zhenjun; Evans, David G.; Duan Xue

2006-01-01

An organic UV absorber has been intercalated into a layered double hydroxide (LDH) host by ion-exchange method using ZnAl-NO 3 -LDH as a precursor with an aqueous solution of the sodium salt of 5-benzotriazolyl-4-hydroxy-3-sec-butylbenzenesulfonic acid (BZO). After intercalation of the UV absorber, the interlayer distance in the LDHs increases from 0.89 to 2.32 nm. Infrared spectra and thermogravimetry and differential thermal analysis (TG-DTA) curves reveal the presence of a complex system of supramolecular host-guest interactions. The thermostability of BZO is markedly enhanced by intercalation in the LDH host. ZnAl-BZO-LDHs/polypropylene composite materials exhibit excellent UV photostability. - Graphical abstract: Intercalation of an organic UV absorber in a layered double hydroxide host leads to an enhancement of its photo- and thermal stability

A Proteomics Approach to Identify New Putative Cardiac Intercalated Disk Proteins

NARCIS (Netherlands)

Soni, Siddarth; Raaijmakers, Antonia J A; Raaijmakers, Linsey M; Damen, J Mirjam A; van Stuijvenberg, Leonie; Vos, Marc A; Heck, Albert J R; van Veen, AAB; Scholten, Arjen

2016-01-01

AIMS: Synchronous beating of the heart is dependent on the efficient functioning of the cardiac intercalated disk (ID). The ID is composed of a complex protein network enabling electrical continuity and chemical communication between individual cardiomyocytes. Recently, several different studies

Renal intercalated cells and blood pressure regulation

Directory of Open Access Journals (Sweden)

Susan M. Wall

2017-12-01

Full Text Available Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Single nucleotide polymorphism discrimination with and without an ethidium bromide intercalator.

Science.gov (United States)

Fenati, Renzo A; Connolly, Ashley R; Ellis, Amanda V

2017-02-15

Single nucleotide polymorphism (SNP) genotyping is an important aspect in understanding genetic variations. Here, we discriminate SNPs using toe-hold mediated displacement reactions. The biological target is an 80 nucleotide long double-stranded-DNA from the mtDNA HV1 region, associated with maternal ancestry. This target has been specially designed with a pendant toehold and a cationic fluorophore, ATTO 647N, as a reporter, produced in a polymerase chain reaction. Rates of reaction for the toehold-polymerase chain reaction products (TPPs) with their corresponding complementary displacing sequences, labelled with a Black Hole Quencher 1, followed the order TPP-Cytosine > TPP-Thymine > TPP-Adenine ≥ TPP-Guanine. Non-complementary rates were the slowest with mismatches involving cytosine. These reactions, operating in a static/or contact mode, gave averaged readouts between SNPs within 15 min (with 80-90% quenching), compared to 25-30 min in previous studies involving fluorescence resonance energy transfer. Addition of an intercalating agent, ethidium bromide, retarded the rate of reaction in which cytosine was involved, presumably through stabilization of the base pairing, which resulted in markedly improved discrimination of cytosine containing SNPs. Copyright © 2016 Elsevier B.V. All rights reserved.

Na-Ion Intercalation and Charge Storage Mechanism in 2D Vanadium Carbide

Energy Technology Data Exchange (ETDEWEB)

Bak, Seong-Min [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA; Qiao, Ruimin [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Yang, Wanli [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley CA 94720 USA; Lee, Sungsik [X-Ray Science Division, Argonne National Laboratory, Argonne IL 60439 USA; Yu, Xiqian [Institute of Physics, Chinese Academy of Science, Beijing 100190 China; Anasori, Babak [Department of Material Science and Engineering, A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia PA 19104 USA; Lee, Hungsui [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA; Gogotsi, Yury [Department of Material Science and Engineering, A.J. Drexel Nanomaterials Institute, Drexel University, Philadelphia PA 19104 USA; Yang, Xiao-Qing [Chemistry Division, Brookhaven National Laboratory, Upton NY 11973 USA

2017-07-14

Two-dimensional vanadium carbide MXene containing surface functional groups (denoted as V2CTx, where Tx are surface functional groups) was synthesized and studied as anode material for Na-ion batteries. V2CTx anode exhibits reversible charge storage with good cycling stability and high rate capability through electrochemical test. The charge storage mechanism of V2CTx material during Na+ intercalation/deintercalation and the redox reaction of vanadium were studied using a combination of synchrotron based X-ray diffraction (XRD), hard X-ray absorption near edge spectroscopy (XANES) and soft X-ray absorption spectroscopy (sXAS). Experimental evidence of a major contribution of redox reaction of vanadium to the charge storage and the reversible capacity of V2CTx during sodiation/desodiation process have been provided through V K-edge XANES and V L2,3-edge sXAS results. A correlation between the CO32- content and Na+ intercalation/deintercalation states in the V2CTx electrode observed from C and O K-edge in sXAS results imply that some additional charge storage reactions may take place between the Na+-intercalated V2CTx and the carbonate based non-aqueous electrolyte. The results of this study will provide valuable information for the further studies on V2CTx as anode material for Na-ion batteries and capacitors.

Copper-mediated reductive dechlorination by green rust intercalated with dodecanoate

DEFF Research Database (Denmark)

Huang, Lizhi; Yin, Zhou; Cooper, Nicola G.A.

2018-01-01

A layered FeII-FeIII hydroxide (green rust, GR) was intercalated with dodecanoate (known as GRC12) and then amended with CuII (GRC12(Cu)) before reaction with chloroform (CF), carbon tetrachloride (CT), trichloroethylene (TCE) or tetrachloroethylene (PCE). Reduction of CT by GRC12(Cu) was 37 times...

Anti-tumour action of 64Cu-bleomycin on Ehrlich ascites tumour cells in vivo

International Nuclear Information System (INIS)

Maki, Hirotoshi; Kawai, Kenichi; Akaboshi, Mitsuhiko

1979-01-01

The anti-tumor action of the complex of Bleomycin (BLM) with high specific-radioactivity 64 Cu on Ehrlich ascites tumour (EAT) was studied in vivo. The 64 Cu-BLM was administered into intraperitoneal cavity of mice from 1 to 4 days after inoculation of EAT cells. The effect of 64 Cu-BLM to suppress the tumour growth as demonstrated by prolonging life span was observed. The amounts of 64 Cu-BLM (800 μCi-8 mg/Kg) were administered at 4, 8 and 16 times separately. Then, the shorter the time interval and the less the amounts of drugs at a time, the higher the suppressing effect for the tumour growth was. It was confirmed that anti-tumour action of 64 Cu-BLM was in all the cases higher than that of BLM alone. (author)

Nanoparticle intercalation-induced interlayer-gap-opened graphene–polyaniline nanocomposite for enhanced supercapacitive performances

Energy Technology Data Exchange (ETDEWEB)

Im, Sungjin; Park, Young Ran [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Park, Sanghyuk [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Department of Energy and Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Kim, Hyeong Jin [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Doh, Ji Hoon [Graphene Research Institute & Department of Chemistry, Sejong University, Seoul 05006 (Korea, Republic of); Division of Electron Microscopy Research, Korea Basic Science Institute (KBSI), Daejeon 34133 (Korea, Republic of); Kwon, Kyungjung [Department of Energy and Mineral Resources Engineering, Sejong University, Seoul 05006 (Korea, Republic of); Hong, Won G. [Division of Electron Microscopy Research, Korea Basic Science Institute (KBSI), Daejeon 34133 (Korea, Republic of); Kim, Byungnam [Radiation Equipment Research Division, Korea Atomic Energy Research Institute, Daejeon 34057 (Korea, Republic of); Yang, Woo Seok [Electronic Material and Device Research Center, Korea Electronics Technology Institute, Seongnam, Gyeonggi-do 13509 (Korea, Republic of); Kim, TaeYoung [Department of Bionanotechnology, Gachon University, Seongnam, Gyeonggi-do 13120 (Korea, Republic of); Hong, Young Joon, E-mail: yjhong@sejong.ac.kr [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 05006 (Korea, Republic of)

2017-08-01

Highlights: • High energy–power supercapacitor electrode is demonstrated using EDLC–PC hybridized rGO–PANi nanocomposite. • A method for perpetuated intercalation of nanoparticles into interlayer gap of rGO is developed. • The intercalaction (i) exfoliates rGO layers, (ii) prevents self-agglomeration, and (iii) enlarges specific surface area of rGO for high power performance. • Electric resistance is substantially reduced by forming more rGO–PANi links via grafting of PANi to well-opened rGO edges. - Abstract: This study demonstrates a method for improving supercapacitive performance of two-dimensional nanosheet-based composite electrode. As a hybridized electrostatic double layer capacitor–electrochemical pseudocapacitor (EDLC–PC) electrode, we synthesized reduced graphene oxide–polyaniline nanofibers (rGO–PANi NFs) composite electrode. For the enhanced supercapacitive performances, insulator silver chloride nanoparticles (AgCl NPs) were intercalated into the interlayer gap of rGO. The AgCl NP intercalation (i) exfoliated rGO layers and (ii) prevented rGO-self-agglomeration that makes it difficult to utilize the high surface-to-volume ratio of ideal mono- (or few-) atomic-thick rGO layers. As a result, (iii) the specific capacitance was improved in accordance with the enlarged specific surface area of rGO. Furthermore, (iv) the well-developed rGO edges, which were opened by the AgCl intercalation, enabled formation of more bonds between PANi and rGO by selective grafting of PANi to the rGO edges. Hence, the bonds of PANi–rGO, as conducting paths, substantially reduced the total electrical resistance. Enhanced specific capacitance, ion diffusion efficiency, and reduced electrical resistance indicated the bi-functional roles of AgCl NP insertion for high performance hybridized EDLC–PC electrodes.

The Effect of Single, Binary and Ternary Anions of Chloride, Carbonate and Phosphate on the Release of 2,4-Dichlorophenoxyacetate Intercalated into the Zn–Al-layered Double Hydroxide Nanohybrid

Directory of Open Access Journals (Sweden)

Zainal Zulkarnain

2009-01-01

Full Text Available Abstract Intercalation of beneficial anion into inorganic host has lead to an opportunity to synthesize various combinations of new organic–inorganic nanohybrids with various potential applications; especially, for the controlled release formulation and storage purposes. Investigation on the release behavior of 2,4-dichlorophenoxyacetate (2,4-D intercalated into the interlayer of Zn–Al-layered double hydroxide (ZAN have been carried out using single, binary and ternary aqueous systems of chloride, carbonate and phosphate. The release behavior of the active agent 2,4-D from its double-layered hydroxide nanohybrid ZANDI was found to be of controlled manner governed by pseudo-second order kinetics. It was found that carbonate medium yielded the highest accumulated release of 2,4-D, while phosphate in combination with carbonate and/or nitrate speeds up the release rate of 2,4-D. These results indicate that it is possible to design and develop new delivery system of latex stimulant compound with controlled release property based on 2,4-D that is known as a substance to increase latex production of rubber tree,Hevea brasiliensis.

Lithium ion intercalation into thin film anatase

International Nuclear Information System (INIS)

Kundrata, I.; Froehlich, K.; Ballo, P.

2015-01-01

The aim of this work is to find the optimal parameters for thin film TiO 2 anatase grown by Atomic layer deposition (ALD) for use as electrode in lithium ion batteries. Two parameters, the optimal film thickness and growth conditions are aimed for. Optimal film thickness for achieving optimum between capacity gained from volume and capacity gained by changing of the intercalation constant and optimal growth conditions for film conformity on structured substrates with high aspect ratio. Here we presents first results from this ongoing research and discuss future outlooks. (authors)

Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology

Science.gov (United States)

Li, Yong-Jun; Sun, Qing-Qing; Chen, Lin; Zhou, Peng; Wang, Peng-Fei; Ding, Shi-Jin; Zhang, David Wei

2012-03-01

We proposed intercalation of hexagonal boron nitride (hBN) in multilayer graphene to improve its performance in ultra-scaled interconnects for integrated circuit. The effect of intercalated hBN layer in bilayer graphene is investigated using non-equilibrium Green's functions. We find the hBN intercalated bilayer graphene exhibit enhanced transport properties compared with pristine bilayer ones, and the improvement is attributed to suppression of interlayer scattering and good planar bonding condition of inbetween hBN layer. Based on these results, we proposed a via structure that not only benefits from suppressed interlayer scattering between multilayer graphene, but also sustains the unique electrical properties of graphene when many graphene layers are stacking together. The ideal current density across the structure can be as high as 4.6×109 A/cm2 at 1V, which is very promising for the future high-performance interconnect.

Hexagonal boron nitride intercalated multi-layer graphene: a possible ultimate solution to ultra-scaled interconnect technology

Directory of Open Access Journals (Sweden)

Yong-Jun Li

2012-03-01

Full Text Available We proposed intercalation of hexagonal boron nitride (hBN in multilayer graphene to improve its performance in ultra-scaled interconnects for integrated circuit. The effect of intercalated hBN layer in bilayer graphene is investigated using non-equilibrium Green's functions. We find the hBN intercalated bilayer graphene exhibit enhanced transport properties compared with pristine bilayer ones, and the improvement is attributed to suppression of interlayer scattering and good planar bonding condition of inbetween hBN layer. Based on these results, we proposed a via structure that not only benefits from suppressed interlayer scattering between multilayer graphene, but also sustains the unique electrical properties of graphene when many graphene layers are stacking together. The ideal current density across the structure can be as high as 4.6×109 A/cm2 at 1V, which is very promising for the future high-performance interconnect.

Antitumour and antiangiogenic activities of [Pt(O,O′‐acac)(γ‐acac)(DMS)] in a xenograft model of human renal cell carcinoma

Science.gov (United States)

Vetrugno, C; Biagioni, F; Calabriso, N; Calierno, M T; Fornai, F; De Pascali, S A; Marsigliante, S; Fanizzi, F P

2016-01-01

Background and Purpose It is thought that the mechanism of action of anticancer chemotherapeutic agents is mainly due to a direct inhibition of tumour cell proliferation. In tumour specimens, the endothelial cell proliferation rate increases, suggesting that the therapeutic effects of anticancer agents could also be attributed to inhibition of tumour angiogenesis. Hence, we investigated the potential effects of [Pt(O,O′‐acac)(γ‐acac)(DMS)] ([Pt(DMS)]), a new platinum drug for non‐genomic targets, on human renal carcinoma and compared them with those of the well‐established anticancer drug, cisplatin. Experimental Approach Tumour growth, tumour cell proliferation and microvessel density were investigated in a xenograft model of renal cell carcinoma, developed by injecting Caki‐1 cells into BALB/c nude mice. The antiangiogenic potential of compounds was also investigated using HUVECs. Key Results Treatment of the Caki‐1 cells with cisplatin or [Pt(DMS)] resulted in a dose‐dependent inhibition of cell survival, but the cytotoxicity of [Pt(DMS)] was approximately fivefold greater than that of cisplatin. [Pt(DMS)] was much more effective than cisplatin at inhibiting tumour growth, proliferation and angiogenesis in vivo, as well as migration, tube formation and MMP1, MMP2 and MMP9 secretion of endothelial cells in vitro. Whereas, cisplatin exerted a greater cytotoxic effect on HUVECs, but did not affect tube formation or the migration of endothelial cells. In addition, treatment of the xenograft mice with [Pt(DMS)] decreased VEGF, MMP1 and MMP2 expressions in tumours. Conclusions and Implications The antiangiogenic and antitumour activities of [Pt(DMS)] provide a solid starting point for its validation as a suitable candidate for further pharmacological testing. PMID:27351124

Intercalation of tartrazine into ZnAl and MgAl layered double hydroxides

Czech Academy of Sciences Publication Activity Database

Beneš, L.; Melánová, Klára; Zima, Vítězslav; Svoboda, Jan

2005-01-01

Roč. 70, č. 2 (2005), s. 259-267 ISSN 0010-0765 Institutional research plan: CEZ:AV0Z40500505 Keywords : intercalation * hydrotalcite Subject RIV: CA - Inorganic Chemistry Impact factor: 0.949, year: 2005

Intercalation of cellulase enzyme into a hydrotalcite layer structure

Science.gov (United States)

Zou, N.; Plank, J.

2015-01-01

A new inorganic-organic hybrid material whereby cellulase enzyme is incorporated into a hydrotalcite type layered double hydroxide (LDH) structure is reported. The Mg2Al-cellulase-LDH was synthesized via co-precipitation from Mg/Al nitrate at pH=9.6. Characterization was performed using X-ray powder diffraction (XRD), small angle X-ray scattering (SAXS), elemental analysis, infrared spectroscopy (IR) and thermogravimetry (TG). From XRD and SAXS measurements, a d-value of ~5.0 nm was identified for the basal spacing of the Mg2Al-cellulase-LDH. Consequently, the cellulase enzyme (hydrodynamic diameter ~6.6 nm) attains a slightly compressed conformation when intercalated. Formation of the LDH hybrid was also confirmed via scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Mg2Al-cellulase-LDH phases appear as ~20 nm thin foils which are intergrown to flower-like aggregates. Activity of the enzyme was retained after deintercalation from the Mg2Al-LDH framework using anion exchange. Accordingly, cellulase is not denatured during the intercalation process, and LDH presents a suitable host structure for time-controlled release of the biomolecule.

Modification and intercalation of layered zirconium phosphates: a solid-state NMR monitoring.

Science.gov (United States)

Bakhmutov, Vladimir I; Kan, Yuwei; Sheikh, Javeed Ahmad; González-Villegas, Julissa; Colón, Jorge L; Clearfield, Abraham

2017-07-01

Several layered zirconium phosphates treated with Zr(IV) ions, modified by monomethoxy-polyethyleneglycol-monophosphate and intercalated with doxorubicin hydrochloride have been studied by solid-state MAS NMR techniques. The organic components of the phosphates have been characterized by the 13 C{ 1 H} CP MAS NMR spectra compared with those of initial compounds. The multinuclear NMR monitoring has provided to establish structure and covalent attachment of organic/inorganic moieties to the surface and interlayer spaces of the phosphates. The MAS NMR experiments including kinetics of proton-phosphorus cross polarization have resulted in an unusual structure of zirconium phosphate 6 combining decoration of the phosphate surface by polymer units and their partial intercalation into the interlayer space. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Transient analysis of intercalation electrodes for parameter estimation

Science.gov (United States)

Devan, Sheba

An essential part of integrating batteries as power sources in any application, be it a large scale automotive application or a small scale portable application, is an efficient Battery Management System (BMS). The combination of a battery with the microprocessor based BMS (called "smart battery") helps prolong the life of the battery by operating in the optimal regime and provides accurate information regarding the battery to the end user. The main purposes of BMS are cell protection, monitoring and control, and communication between different components. These purposes are fulfilled by tracking the change in the parameters of the intercalation electrodes in the batteries. Consequently, the functions of the BMS should be prompt, which requires the methodology of extracting the parameters to be efficient in time. The traditional transient techniques applied so far may not be suitable due to reasons such as the inability to apply these techniques when the battery is under operation, long experimental time, etc. The primary aim of this research work is to design a fast, accurate and reliable technique that can be used to extract parameter values of the intercalation electrodes. A methodology based on analysis of the short time response to a sinusoidal input perturbation, in the time domain is demonstrated using a porous electrode model for an intercalation electrode. It is shown that the parameters associated with the interfacial processes occurring in the electrode can be determined rapidly, within a few milliseconds, by measuring the response in the transient region. The short time analysis in the time domain is then extended to a single particle model that involves bulk diffusion in the solid phase in addition to interfacial processes. A systematic procedure for sequential parameter estimation using sensitivity analysis is described. Further, the short time response and the input perturbation are transformed into the frequency domain using Fast Fourier Transform

Electrochemical potassium-ion intercalation in NaxCoO2: a novel cathode material for potassium-ion batteries.

Science.gov (United States)

Sada, Krishnakanth; Senthilkumar, Baskar; Barpanda, Prabeer

2017-07-27

Reversible electrochemical potassium-ion intercalation in P2-type Na x CoO 2 was examined for the first time. Hexagonal Na 0.84 CoO 2 platelets prepared by a solution combustion synthesis technique were found to work as an efficient host for K + intercalation. They deliver a high reversible capacity of 82 mA h g -1 , good rate capability and excellent cycling performance up to 50 cycles.

DNA minor groove alkylating agents.

Science.gov (United States)

Denny, W A

2001-04-01

Recent work on a number of different classes of anticancer agents that alkylate DNA in the minor groove is reviewed. There has been much work with nitrogen mustards, where attachment of the mustard unit to carrier molecules can change the normal patterns of both regio- and sequence-selectivity, from reaction primarily at most guanine N7 sites in the major groove to a few adenine N3 sites at the 3'-end of poly(A/T) sequences in the minor groove. Carrier molecules discussed for mustards are intercalators, polypyrroles, polyimidazoles, bis(benzimidazoles), polybenzamides and anilinoquinolinium salts. In contrast, similar targeting of pyrrolizidine alkylators by a variety of carriers has little effect of their patterns of alkylation (at the 2-amino group of guanine). Recent work on the pyrrolobenzodiazepine and cyclopropaindolone classes of natural product minor groove binders is also reviewed.

Synthesis and characterization of Mg-Al-layered double hydroxides intercalated with cubane-1,4-dicarboxylate anions.

Science.gov (United States)

Rezvani, Zolfaghar; Arjomandi Rad, Farzad; Khodam, Fatemeh

2015-01-21

In the present work, Mg2Al-layered double hydroxide (LDH) intercalated with cubane-1,4-dicarboxylate anions was prepared from the reaction of solutions of Mg(ii) and Al(iii) nitrate salts with an alkaline solution of cubane-1,4-dicarboxylic acid by using the coprecipitation method. The successful preparation of a nanohybrid of cubane-1,4-dicarboxylate(cubane-dc) anions with LDH was confirmed by powder X-ray diffraction, FTIR spectroscopy and thermal gravimetric analysis (TGA). The increase in the basal spacing of LDHs from 8.67 Å to 13.40 Å shows that cubane-dc anions were successfully incorporated into the interlayer space. Thermogravimetric analyses confirm that the thermal stability of the intercalated cubane-dc anions is greater than that of the pure form before intercalation because of host-guest interactions involving hydrogen bonds. The interlayer structure, hydrogen bonding, and subsequent distension of LDH compounds containing cubane-dc anions were shown by molecular simulation. The RDF (radial distribution function), mean square displacement (MSD), and self-diffusion coefficient were calculated using the trajectory files on the basis of molecular dynamics (MD) simulations, and the results indicated that the cubane-dc anions were more stable when intercalated into the LDH layers. A good agreement was obtained between calculated and measured X-ray diffraction patterns and between experimental and calculated basal spacings.

Histological study of human sublingual gland with special emphasis on intercalated and striated ducts

International Nuclear Information System (INIS)

Rana, R.; Minhas, L.A.; Mubarik, A.

2012-01-01

Objective: To study the histomorphological characteristics of human sublingual gland, specially of intercalated and striated ducts. Study design: Descriptive study Place and duration of study: Army Medical College from Jan 2002 to Dec 2002 Materials and methods: Fifteen sublingual glands (right and left) from postmortem cases were obtained from District Headquarter Hospital Rawalpindi, within twelve hours of death. Five micrometer thick sections were made and stained with Haematoxylin and Eosin (H and E). Morphology of intercalated and striated ducts was studied and their number was counted. Results: The mean number of intercalated ducts in the right gland 'a'and 'b' parts, and in the left gland 'a' and 'b' parts was 1.45+-0.14, 1.39+-.009, 1.31+-0.11 and 1.18+-0.10 respectively. The mean diameter of intercalated ducts in the same parts was 19.76+-0.44 micro m, 20.6+-0.53 micro m, 20.34+-0.49 micro m and 19.84+-0.98 micro m respectively. The mean number of striated ducts in the right gland ''a'' and ''b'' parts, and in the left gland ''a'' and ''b'' parts was 0.55+-.008, 0.57+-.008, 0.80+-0.14 and 0.80+-0.14 while mean diameter of striated ducts in the right gland ''a'' and ''b'' parts, and in the left gland ''a'' and ''b'' parts was 49.90+-4.70 micro m, 53.23+-2.50 micro m, 61.68+-3.93 micro m and 57.73+-2.85 micro m respectively. Conclusion: The difference between the mean number and diameter of the ducts of right and left glands was statistically insignificant. (author)

Effects of Intercalation on the Hole Mobility of Amorphous Semiconducting Polymer Blends

KAUST Repository

Cates, Nichole C.; Gysel, Roman; Dahl, Jeremy E. P.; Sellinger, Alan; McGehee, Michael D.

2010-01-01

Fullerenes have been shown to intercalate between the side chains of many crystalline and semicrystalline polymers and to affect the properties of polymer:fullerene bulk heterojunction solar cells. Here we present the first in-depth study

Neutron scattering in chemistry (scattering from layer lattices and their intercalation compounds - an illustration)

International Nuclear Information System (INIS)

White, J.W.

1983-01-01

Three cases of molecules on a free surface or inside layer lattice intercalation compounds are discussed to illustrate the use of neutron scattering techniques. The first is the second stage alkali metal-graphite intercalation compounds such as C 24 Cs which adsorb hydrogen, methane and other gases. The second case is methane physisorbed on the basal plane of graphite where the methane-methane interactions are relatively strong. Rotational tunnelling spectroscopy is sensitive to the parameters of the potential. The third case is that of water physisorbed on clay materials such as vermiculite or montmorillonite where the layer thickness can be changed from one to fifty layers. (UK)

Ultrastructural and biochemical localization of N-RAP at the interface between myofibrils and intercalated disks in the mouse heart.

Science.gov (United States)

Zhang, J Q; Elzey, B; Williams, G; Lu, S; Law, D J; Horowits, R

2001-12-11

N-RAP is a recently discovered muscle-specific protein found at cardiac intercalated disks. Double immunogold labeling of mouse cardiac muscle reveals that vinculin is located immediately adjacent to the fascia adherens region of the intercalated disk membrane, while N-RAP extends approximately 100 nm further toward the interior of the cell. We partially purified cardiac intercalated disks using low- and high-salt extractions followed by density gradient centrifugation. Immunoblots show that this preparation is highly enriched in desmin and junctional proteins, including N-RAP, talin, vinculin, beta1-integrin, N-cadherin, and connexin 43. Electron microscopy and immunolabeling demonstrate that N-RAP and vinculin are associated with the large fragments of intercalated disks that are present in this preparation, which also contains numerous membrane vesicles. Detergent treatment of the partially purified intercalated disks removed the membrane vesicles and extracted vinculin and beta1-integrin. Further separation on a sucrose gradient removed residual actin and myosin and yielded a fraction morphologically similar to fasciae adherentes that was highly enriched in N-RAP, N-cadherin, connexin 43, talin, desmin, and alpha-actinin. The finding that N-RAP copurifies with detergent-extracted intercalated disk fragments even though beta-integrin and vinculin have been completely removed suggests that N-RAP association with the adherens junction region is mediated by the cadherin system. Consistent with this hypothesis, we found that recombinant N-RAP fragments bind alpha-actinin in a gel overlay assay. In addition, immunofluorescence shows that N-RAP remains bound at the ends of isolated, detergent-treated cardiac myofibrils. These results demonstrate that N-RAP remains tightly bound to myofibrils and fasciae adherentes during biochemical purification and may be a key constituent in the mechanical link between these two structures.

Exfoliation and van der Waals heterostructure assembly of intercalated ferromagnet Cr1/3TaS2

Science.gov (United States)

Yamasaki, Yuji; Moriya, Rai; Arai, Miho; Masubuchi, Satoru; Pyon, Sunseng; Tamegai, Tsuyoshi; Ueno, Keiji; Machida, Tomoki

2017-12-01

Ferromagnetic van der Waals (vdW) materials are in demand for spintronic devices with all-two-dimensional-materials heterostructures. Here, we demonstrate mechanical exfoliation of magnetic-atom-intercalated transition metal dichalcogenide Cr1/3TaS2 from its bulk crystal; previously such intercalated materials were thought difficult to exfoliate. Magnetotransport in exfoliated tens-of-nanometres-thick flakes revealed ferromagnetic ordering below its Curie temperature T C ~ 110 K as well as strong in-plane magnetic anisotropy; these are identical to its bulk properties. Further, van der Waals heterostructure assembly of Cr1/3TaS2 with another intercalated ferromagnet Fe1/4TaS2 is demonstrated using a dry-transfer method. The fabricated heterojunction composed of Cr1/3TaS2 and Fe1/4TaS2 with a native Ta2O5 oxide tunnel barrier in between exhibits tunnel magnetoresistance (TMR), revealing possible spin injection and detection with these exfoliatable ferromagnetic materials through the vdW junction.

Mössbauer, XRD and TEM Study on the Intercalation and the Release of Drugs in/from Layered Double Hydroxides

Directory of Open Access Journals (Sweden)

E. Kuzmann

2015-12-01

Full Text Available Layered double hydroxides (LDHs are one of the very important nano-carriers for drug delivery, due to their many advantageous features, such as the ease and low-cost of preparation, low cytotoxicity, good biocompatibility, protection for the intercalated drugs, and the capacity to facilitate the uptake of the loaded drug in the cells. In our previous studies, Mössbauer spectroscopy was applied to monitor structural changes occurring during the incorporation of Fe(III in MgFe- and CaFe-LDHs, and the intercalation of various organic compounds in anionic form. Recently, we have successfully elaborated a protocol for the intercalation and release of indol-2-carboxylate and L-cysteinate in CaFe-LDH. The corresponding structural changes in the LDH samples were studied by XRD, HR-TEM and 57Fe Mössbauer spectroscopy. The Mössbauer spectra reflected small but significant changes upon both the intercalation and the release of drugs. The changes in the basal distances could be followed by XRD measurements, and HR-TEM images made these changes visible.

Large-scale symmetry-adapted perturbation theory computations via density fitting and Laplace transformation techniques: investigating the fundamental forces of DNA-intercalator interactions.

Science.gov (United States)

Hohenstein, Edward G; Parrish, Robert M; Sherrill, C David; Turney, Justin M; Schaefer, Henry F

2011-11-07

Symmetry-adapted perturbation theory (SAPT) provides a means of probing the fundamental nature of intermolecular interactions. Low-orders of SAPT (here, SAPT0) are especially attractive since they provide qualitative (sometimes quantitative) results while remaining tractable for large systems. The application of density fitting and Laplace transformation techniques to SAPT0 can significantly reduce the expense associated with these computations and make even larger systems accessible. We present new factorizations of the SAPT0 equations with density-fitted two-electron integrals and the first application of Laplace transformations of energy denominators to SAPT. The improved scalability of the DF-SAPT0 implementation allows it to be applied to systems with more than 200 atoms and 2800 basis functions. The Laplace-transformed energy denominators are compared to analogous partial Cholesky decompositions of the energy denominator tensor. Application of our new DF-SAPT0 program to the intercalation of DNA by proflavine has allowed us to determine the nature of the proflavine-DNA interaction. Overall, the proflavine-DNA interaction contains important contributions from both electrostatics and dispersion. The energetics of the intercalator interaction are are dominated by the stacking interactions (two-thirds of the total), but contain important contributions from the intercalator-backbone interactions. It is hypothesized that the geometry of the complex will be determined by the interactions of the intercalator with the backbone, because by shifting toward one side of the backbone, the intercalator can form two long hydrogen-bonding type interactions. The long-range interactions between the intercalator and the next-nearest base pairs appear to be negligible, justifying the use of truncated DNA models in computational studies of intercalation interaction energies.

Preparation and intercalation study of ternary transition elements chalcogenides AxMXn

International Nuclear Information System (INIS)

Kassem, M.

1999-01-01

The crystalline powders of transition elements chalcogenides have been prepared by solid-solid reaction method starting from elemental powders in evacuated and sealed quartz tubes heated at various temperatures depending on the compound to be prepared. The structures and composition of the obtained compounds have been studied by X-ray diffraction and X-ray fluorescence techniques. Intercalation compounds Co x MX 2 have been obtained by heating the powder with elemental cobalt at 500 Centigrade. The results of the structural studies show that the intercalation of cobalt is a regular phenomena and the cobalt atoms play the role of staples for the layers constructing the crystalline structure of starting materials. This stapling phenomena is accompanied by changes in distance between the layers and therefore changes in the length of bonds between the elements of compound. The changes in the length of bonds have been confirmed by the results of FTIR studies.(author)

In situ oligomerization of 2-(thiophen-3-yl)acetate intercalated into Zn{sub 2}Al layered double hydroxide

Energy Technology Data Exchange (ETDEWEB)

Tronto, Jairo, E-mail: jairotronto@ufv.br [Universidade Federal de Viçosa, Instituto de Ciências Exatas e Tecnológicas, Campus de Rio Parsanaíba, Rodovia BR 354 km 310, Cx. Postal 22, CEP, 38.810-000 Rio Paranaíba, MG (Brazil); Pinto, Frederico G.; Costa, Liovando M. da [Universidade Federal de Viçosa, Instituto de Ciências Exatas e Tecnológicas, Campus de Rio Parsanaíba, Rodovia BR 354 km 310, Cx. Postal 22, CEP, 38.810-000 Rio Paranaíba, MG (Brazil); Leroux, Fabrice; Dubois, Marc [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, BP 80026, F-6317 Clermont-Ferrand (France); Valim, João B. [Universidade de São Paulo, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Departamento de Química, Av. dos Bandeirantes 3900, CEP 14.040-901, Ribeirão Preto, SP (Brazil)

2015-01-15

A layered double hydroxide (LDH) with cation composition Zn{sub 2}Al was intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers. To achieve in situ polymerization and/or oligomerization of the intercalated monomers, soft thermal treatments were carried out, and subsequent hybrid LDH materials were analyzed by means of several characterization techniques using powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), {sup 13}C CP–MAS nuclear magnetic resonance (NMR), electron spin resonance (EPR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), inductively coupled plasma optical emission spectroscopy (ICP–OES), and elemental analysis. PXRD analysis suggested that the intercalated monomers formed a bilayer. Thermal treatment of the hybrid LDH assembly above 120 °C provokes partially the breakdown of the layered structure, generating the phase zincite. EPR results indicated that vicinal monomers (oligomerization) were bound to each other after hydrothermal or thermal treatment, leading to a polaron response characteristic of electron conductivity localized on a restricted number of thiophene-based monomer segments. Localized unpaired electrons exist in the material and interact with the {sup 27}Al nuclei of the LDH layers by superhyperfine coupling. These unpaired electrons also interact with the surface of ZnO (O{sup 2−} vacancies), formed during the thermal treatments. - Graphical abstract: We synthesized a layered double hydroxide (LDH) with cation composition Zn{sub 2}Al, intercalated with 2-(thiophen-3-yl)acetate (3-TA) monomers, by coprecipitation at constant pH. We thermally treated the material, to achieve in situ polymerization and/or oligomerization of the intercalated monomers. - Highlights: • A Zn{sub 2}Al–LDH was intercalated with 2-(thiophen-3-yl)acetate monomers. • To achieve in situ oligomerization of the monomers, thermal treatments were made. �

Design and Synthesis of Mono- and Bi-phasic Nano hybrids for Simultaneous Release of Two Active Agents

International Nuclear Information System (INIS)

Mohd Zobir Hussein; Abdul Rahman, N.S.S.; Siti Halimah Sarijo

2011-01-01

Organic-Inorganic nano hybrid materials, especially of host-guest types exhibit an excellent opportunity for a wide range of organic active agents for the formation of organic-inorganic nano hybrids which may find potential uses with tailor made application. A number of groups have studied the agrochemical intercalates of LDHs as potential reservoir and controlled release system. Agrochemicals, in particular herbicides such as 4-(2,4-dichlorophenoxy)butyrate (DPBA) and 2-(3- chlorophenoxy)propionate (CPPA) are commonly used in agriculture sector. Simultaneous incorporation of both phenoxy herbicides anions into Zn-Al-LDH (ZAL) have been successfully prepared by direct co-precipitation method, labeled as NCDD. Both anions were intercalated simultaneously into the inorganic ZAL interlayers and X-ray diffraction data reveal that the basal spacing increased from 8.9 to 25.1 Angstrom upon the intercalation. PXRD patterns of single anion intercalation using CPPA and DPBA labeled as NC and ND nano hybrid, respectively was simulated and found that the PXRD patterns composed of 90 % ND and 10 % NC and this show relatively similar PXRD features to that of NCDD nano hybrid. This indicates that NCDD is possibly composed of mixed phases of each of NC and ND. UV-VIS spectroscopy study shows the percentage loading of CPPA and DPBA is 2.5 % (w/w) and 41.4 % (w/w), respectively. These values are equivalent to about 5.7 % and 94.3 % contribution of CPPA and DPBA, which agree nicely with the values obtained from simulated PXRD patterns. The simultaneous release of the two herbicides from its nano hybrid exhibit different release kinetics, where DPBA shows higher percentage release than CPPA. The release process was found to be controlled by pseudo-second order kinetic. The results presented show that the intercalation and release of the dual herbicides are influenced by the anion size. The abundance of DPBA anion between the ZAL interlayer is due to its higher affinity towards LDH

Optimum conditions for intercalation of lacunary tungstophosphate(V) anions into layered Ni(II)-Zn(II) hydroxyacetate

International Nuclear Information System (INIS)

Ballesteros, M. Angeles; Ulibarri, M. Angeles; Rives, Vicente; Barriga, Cristobalina

2008-01-01

Acetate containing nickel-zinc hydroxysalts (LHS-Ni-Zn) have been synthesized by coprecipitation and hydrothermal treatment. The acetate anions were exchanged with PW 12 O 40 3- anions, and optimum conditions to attain the maximum level of W in the compound have been identified. The W intercalated compound was characterized by powder X-ray diffraction, FT-IR spectroscopy, thermogravimetric and differential thermal analyses, scanning electron microscopy and transmission electron microscopy. The exchange of LHS-Ni-Zn with PW 12 O 40 3- at pH=3 for 72 h leads to a solid with a basal spacing of 9.62 A and a W content (weight) of 37%. The hydrothermal treatment at 90 deg. C for 24 h increases this value to 48% with a W/Zn molar ratio of 1.38, which corresponds to a layered compound with lacunary tungstophosphate anions in the interlayer space. The intercalated solid is stable up to 250 deg. C, the layer structure collapses on dehydroxylation and amorphous compounds were identified at 500 deg. C. Two crystalline phases, NiO (rock salt) and a solid solution (Zn 1-x Ni x )WO 4 , were identified by powder X-ray diffraction at high temperature (ca. 1000 deg. C). - Graphical abstract: Optimum conditions for intercalation of Keggin-type anions in Ni, Zn hydroxysalts have been identified. Lacunary species are formed via partial depolymerization of the starting anion. The thermal decomposition of the intercalated phases has been also studied

First-principles investigation of aluminum intercalation and diffusion in TiO2 materials: Anatase versus rutile

Science.gov (United States)

Tang, Weiqiang; Xuan, Jin; Wang, Huizhi; Zhao, Shuangliang; Liu, Honglai

2018-04-01

Aluminum-ion batteries, emerging as a promising post-lithium battery solution, have been a subject of increasing research interest. Yet, most existing aluminum-ion research has focused on electrode materials development and synthesis. There has been a lack of fundamental understanding of the electrode processes and thus theoretical guidelines for electrode materials selection and design. In this study, by using density functional theory, we for the first time report a first-principles investigation on the thermodynamic and kinetic properties of aluminum intercalation into two common TiO2 polymorphs, i.e., anatase and rutile. After examining the aluminum intercalation sites, intercalation voltages, storage capacities and aluminum diffusion paths in both cases, we demonstrate that the stable aluminum intercalation site locates at the center of the O6 octahedral for TiO2 rutile and off center for TiO2 anatase. The maximum achievable Al/Ti ratios for rutile and anatase are 0.34375 and 0.36111, respectively. Although rutile is found to have an aluminum storage capacity slightly higher than anatase, the theoretical specific energy of rutile can reach 20.90 Wh kg-1, nearly twice as high as anatase (9.84 Wh kg-1). Moreover, the diffusion coefficient of aluminum ions in rutile is 10-9 cm2 s-1, significantly higher than that in anatase (10-20 cm2 s-1). In this regard, TiO2 rutile appears to be a better candidate than anatase as an electrode material for aluminum-ion batteries.

Effects of surfactants on microwave-assisted solid-state intercalation of poly(carbazole) in Bentonite

International Nuclear Information System (INIS)

Riaz, Ufana; Ashraf, S. M.; Khan, Nisha

2011-01-01

The present preliminary investigation reports, for the first time, the effects of typical cationic and anionic surfactants on the microwave-assisted solid-state intercalation and polymerization of carbazole (Cz) in the basal spacings of Bentonite. The intercalation of cetyl pyridinium chloride (CPCl), a cationic surfactant, and naphthalene sulfonic acid (NSA), an anionic surfactant, in Bentonite was carried out at two loadings—25 and 50 wt%—using microwave irradiation. The in situ polymerization of Cz was successfully carried out into the surfactant-modified galleries of Bentonite. This was confirmed by Gel permeation chromatography (GPC). The intercalation of poly(carbazole) (PCz) was confirmed by FT-IR, UV–Visible, and XRD analyses. Although polymerization was carried out in the solid-state, the UV–Visible spectra revealed the doped state of PCz and the presence of a charge carrier tail. The XRD studies showed that the increase in the height of the galleries was higher in case of Bentonite/CPCl/PCz nanocomposites as compared to Bentonite/NSA/PCz nanocomposites. It also revealed different orientations of the two surfactants in the galleries of the clay. The average particle size of Bentonite/CPCl/PCz (1:0.25:0.25) and (1:0.5:0.5) nanocomposites was found to be in the range of 25–35 and 50–60 nm, respectively. The Bentonite/NSA/PCz (1:0.25:0.25) and (1:0.5:0.5) nanocomposites showed the average particle size in the range of 20–30 nm and 40–50 nm, respectively. The results revealed that both cationic and anionic surfactants strongly influenced the morphology of Bentonite/PCz nanocomposites. The difference in the mechanisms of solid-state intercalation of PCz in the presence of these surfactants has been proposed.

Two half-sandwiched ruthenium (II compounds containing 5-fluorouracil derivatives: synthesis and study of DNA intercalation.

Directory of Open Access Journals (Sweden)

Zhao-Jun Li

Full Text Available Two novel coordination compounds of half-sandwiched ruthenium(II containing 2-(5-fluorouracil-yl-N-(pyridyl-acetamide were synthesized, and their intercalation binding modes with calf thymus DNA were revealed by hyperchromism of ultraviolet-visible spectroscopy; the binding constants were determined according to a Langmuir adsorption equation that was deduced on the base of careful cyclic voltammetry measurements. The two compounds exhibited DNA intercalation binding activities with the binding constants of 1.13×106 M-1 and 5.35 ×105 M-1, respectively.

Capacitors on the basis of intercalate GaSe

Directory of Open Access Journals (Sweden)

Kovalyuk Z. D.

2010-06-01

Full Text Available The compound GaSe is obtained by the technique of intercalation of a GaSe single crystal in a melt of the ferroelectric salt KNO3. The x-ray analysis of its crystal structure has been carried out and dielectric frequency characteristics of samples has been measured. It is estab-lished, that accumulation of electric charges occurs in the examined examples in frequency area 100—1000 Hz. A sample of filter capacitor has been created on the basis of the re-ceived compounds.

Electronic properties and orbital-filling mechanism in Rb-intercalated copper phthalocyanine

NARCIS (Netherlands)

Evangelista, F.; Gotter, R.; Mahne, N.; Nannarone, S.; Ruocco, A.; Rudolf, P.

2008-01-01

The evolution of the electronic properties of a thin film of copper phthalocyanine deposited on Al(100) and progressively intercalated with rubidium atoms was followed by photoemission and X-ray absorption spectroscopies. Electron donation from the Rb atoms to the C32H16N8Cu molecules results in the

Wnt5 is required for notochord cell intercalation in the ascidian Halocynthia roretzi.

Science.gov (United States)

Niwano, Tomoko; Takatori, Naohito; Kumano, Gaku; Nishida, Hiroki

2009-08-25

In the embryos of various animals, the body elongates after gastrulation by morphogenetic movements involving convergent extension. The Wnt/PCP (planar cell polarity) pathway plays roles in this process, particularly mediolateral polarization and intercalation of the embryonic cells. In ascidians, several factors in this pathway, including Wnt5, have been identified and found to be involved in the intercalation process of notochord cells. In the present study, the role of the Wnt5 genes, Hr-Wnt5alpha (Halocynthia roretzi Wnt5alpha) and Hr-Wnt5beta, in convergent extension was investigated in the ascidian H. roretzi by injecting antisense oligonucleotides and mRNAs into single precursor blastomeres of various tissues, including notochord, at the 64-cell stage. Hr-Wnt5alpha is expressed in developing notochord and was essential for notochord morphogenesis. Precise quantitative control of its expression level was crucial for proper cell intercalation. Overexpression of Wnt5 proteins in notochord and other tissues that surround the notochord indicated that Wnt5alpha plays a role within the notochord, and is unlikely to be the source of polarizing cues arising outside the notochord. Detailed mosaic analysis of the behaviour of individual notochord cells overexpressing Wnt5alpha indicated that a Wnt5alpha-manipulated cell does not affect the behaviour of neighbouring notochord cells, suggesting that Wnt5alpha works in a cell-autonomous manner. This is further supported by comparison of the results of Wnt5alpha and Dsh (Dishevelled) knockdown experiments. In addition, our results suggest that the Wnt/PCP pathway is also involved in mediolateral intercalation of cells of the ventral row of the nerve cord (floor plate) and the endodermal strand. The present study highlights the role of the Wnt5alpha signal in notochord convergent extension movements in ascidian embryos. Our results raise the novel possibility that Wnt5alpha functions in a cell-autonomous manner in

Enantiospecific kinking of DNA by a partially intercalating metal complex

KAUST Repository

Reymer, Anna

2012-01-01

Opposite enantiomers of [Ru(phenanthroline) 3] 2+ affect the persistence length of DNA differently, a long speculated effect of helix kinking. Our molecular dynamics simulations confirm a substantial change of duplex secondary structure produced by wedge-intercalation of one but not the other enantiomer. This effect is exploited by several classes of DNA operative proteins. © The Royal Society of Chemistry 2012.

Rechargeable Aqueous Zinc-Ion Battery Based on Porous Framework Zinc Pyrovanadate Intercalation Cathode

KAUST Repository

Xia, Chuan; Guo, Jing; Lei, Yongjiu; Liang, Hanfeng; Zhao, Chao; Alshareef, Husam N.

2017-01-01

metal pyrovanadate compounds. The zinc pyrovanadate nanowires show significantly improved electrochemical performance when used as intercalation cathode for aqueous zinc–ion battery. Specifically, the ZVO cathode delivers high capacities of 213 and 76 m

Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

International Nuclear Information System (INIS)

Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong

2017-01-01

In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)

2017-04-15

In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

Geometric stability, electronic structure, and intercalation mechanism of Co adatom anchors on graphene sheets

International Nuclear Information System (INIS)

Tang, Yanan; Chen, Weiguang; Li, Chenggang; Dai, Xianqi; Li, Wei

2015-01-01

We perform a systematic study of the adsorption of Co adatom on monolayer and bilayer graphene sheets, and the calculated results are compared through the van der Waals density functional (vdW-DF) and the generalized gradient approximation of Perdew, Burke and Ernzernhof (GGA + PBE) methods. For the single Co adatom, its adsorption energy at vacancy site was found to be larger than at the high-symmetry adsorption sites. For the different vdW corrections, the calculated adsorption energies of Co adatom on graphene substrates are slightly changed to some extent, but they do not affect the most preferable adsorption configurations. NEB calculations prove that the Co adatom has smaller energy barrier within pristine bilayer graphene (PBG) than that on the upper layer, indicating the high mobility of Co atom anchors at overlayer and easily aggregates. For the PBG substrate, the Co adatom intercalates into graphene sheets with a large energy barrier (9.29 eV). On the bilayer graphene with a single-vacancy (SV), the Co adatom can easily be trapped at the SV site and intercalates into graphene sheets with a much lower energy barrier (2.88 eV). These results provide valuable information on the intercalation reaction and the formation mechanism of metal impurity in graphene sheets. (paper)

Composition driven monolayer to bilayer transformation in a surfactant intercalated Mg-Al layered double hydroxide.

Science.gov (United States)

Naik, Vikrant V; Chalasani, Rajesh; Vasudevan, S

2011-03-15

The structure and organization of dodecyl sulfate (DDS) surfactant chains intercalated in an Mg-Al layered double hydroxide (LDH), Mg(1-x)Alx(OH)2, with differing Al/Mg ratios has been investigated. The Mg-Al LDHs can be prepared over a range of compositions with x varying from 0.167 to 0.37 and therefore provides a simple system to study how the organization of the alkyl chains of the intercalated DDS anions change with packing density; the Al/Mg ratio or x providing a convenient handle to do so. Powder X-ray diffraction measurements showed that at high packing densities (x ≥ 0.3) the alkyl chains of the intercalated dodecyl sulfate ions are anchored on opposing LDH sheets and arranged as bilayers with an interlayer spacing of ∼27 Å. At lower packing densities (x flat in the galleries with an interlayer spacing of ∼8 Å. For the in between compositions, 0.2 ≤ x organization of the chains and the interlayer spacing. The simulations are able to reproduce the composition driven monolayer to bilayer transformation in the arrangement of the intercalated surfactant chains and in addition provide insights into the factors that decide the arrangement of the surfactant chains in the two situations. In the bilayer arrangement, it is the dispersive van der Waals interactions between chains in opposing layers of the anchored bilayer that is responsible for the cohesive energy of the solid whereas at lower packing densities, where a monolayer arrangement is favored, Coulomb interactions between the positively charged Mg-Al LDH sheets and the negatively charged headgroup of the DDS anion dominate.

Preparation of 5-benzotriazolyl-4-hydroxy-3- sec-butylbenzenesulfonate anion-intercalated layered double hydroxide and its photostabilizing effect on polypropylene

Science.gov (United States)

Li, Dianqing; Tuo, Zhenjun; Evans, David G.; Duan, Xue

2006-10-01

An organic UV absorber has been intercalated into a layered double hydroxide (LDH) host by ion-exchange method using ZnAl-NO 3-LDH as a precursor with an aqueous solution of the sodium salt of 5-benzotriazolyl-4-hydroxy-3- sec-butylbenzenesulfonic acid (BZO). After intercalation of the UV absorber, the interlayer distance in the LDHs increases from 0.89 to 2.32 nm. Infrared spectra and thermogravimetry and differential thermal analysis (TG-DTA) curves reveal the presence of a complex system of supramolecular host-guest interactions. The thermostability of BZO is markedly enhanced by intercalation in the LDH host. ZnAl-BZO-LDHs/polypropylene composite materials exhibit excellent UV photostability.

Electrical and mechanical properties of poly(ethylene oxide)/intercalated clay polymer electrolyte

International Nuclear Information System (INIS)

Moreno, Mabel; Quijada, Raúl; Santa Ana, María A.; Benavente, Eglantina; Gomez-Romero, Pedro; González, Guillermo

2011-01-01

Highlights: ► Poly(ethylene oxide)/intercalated clay nanocomposite as filler in solid poly(ethylene oxide) electrolytes. ► Nanocomposite filler improves mechanical properties, transparency, and conductivity of poly(ethylene oxide) electrolyte films. ► Nanocomposite is more effective than unmodified clay in improving polymer electrolyte properties. ► Low Li/polymer ratio avoids crystalline Li complexes, so effects mainly arise from the polymer. ► High nanocomposite/poly(ethylene oxide)-matrix affinity enhances microhomogeneity in the polyelectrolyte. - Abstract: Solvent-free solid polymer electrolytes (SPEs) based on two different poly(ethylene oxide), PEO Mw 600,000 and 4,000,000 and intercalated clays are reported. The inorganic additives used were lithiated bentonite and the nanocomposite PEO-bentonite with the same polymer used as matrix. SPE films, obtained in the scale of grams by mixing the components in a Brabender-type batch mixer and molding at 130 °C, were characterized by X-ray diffraction analysis, UV–vis spectroscopy, and thermal analysis. During the preparation of the films, the unmodified clay got intercalated in situ. Comparative analysis of ionic conductivity and mechanical properties of the films show that the conductivity increases with the inclusion of fillers, especially for the polymer with low molecular weight. This effect is more pronounced when using PEO-bentonite as additive. Under selected work conditions, avoiding the presence of crystalline lithium complexes, observed effects are mainly centered on the polymer. An explanation, considering the higher affinity between the modified clay and PEO matrix which leads to differences in the micro homogeneity degree between both types of polymer electrolytes is proposed.

DNA intercalation studies and antimicrobial activity of Ag@ZrO2 core–shell nanoparticles in vitro

International Nuclear Information System (INIS)

Dhanalekshmi, K.I.; Meena, K.S.

2016-01-01

Ag@ZrO 2 core–shell nanoparticles were prepared by one pot simultaneous reduction of AgNO 3 and hydrolysis of zirconium (IV) isopropoxide. The formation of core–shell nanoparticles was confirmed by absorption, XRD, and HR-TEM techniques. The antibacterial activity of Ag@ZrO 2 core–shell nanoparticles against Escherichia coli and Staphylococcus aureus and the antifungal properties against Candida albicans, Candida glabrata, Aspergillus niger and Aspergillus flavus were examined by the agar diffusion method. DNA intercalation studies were carried out in CT-DNA. As a result ZrO 2 supported on the surface of AgNPs not only prevented aggregation, but also proved to have enhanced antimicrobial activity and DNA intercalation than the Ag nanoparticles. - Highlights: • Ag@ZrO 2 core–shell nanoparticles were prepared by one pot synthesis. • The ZrO 2 coated AgNPs prevent aggregation and enhanced stability. • The surfaced modified AgNPs showed higher antimicrobial activity. • DNA intercalation studies show better binding affinity of core–shell NPs.

Intercalating dye as an acceptor in quantum-dot-mediated FRET

International Nuclear Information System (INIS)

Lim, Teck Chuan; Bailey, Vasudev J; Wang, T-H; Ho, Y-P

2008-01-01

Fluorescence resonance energy transfer (FRET) is a popular tool to study intermolecular distances and characterize structural or conformational changes of biological macromolecules. We investigate a novel inorganic/organic FRET pair with quantum dots (QDs) as donors and DNA intercalating dyes, BOBO-3, as acceptors by using DNA as a linker. Typically, FRET efficiency increases with the number of stained DNA linked to a QD. However, with the use of intercalating dyes, we demonstrate that FRET efficiency at a fixed DNA:QD ratio can be further enhanced by increasing the number of dyes stained to a DNA strand through the use of an increased staining dye/bp ratio. We exploit this flexibility in the staining ratio to maintain a high FRET efficiency of >0.90 despite a sixfold decrease in DNA concentration. Having characterized this new QD-mediated FRET system, we test this system in a cellular environment using nanocomplexes generated by encapsulating DNA with commercial non-viral gene carriers. Using this novel FRET pair, we are able to monitor the configuration changes and fate of the DNA nanocomplexes during intracellular delivery, thereby providing an insight into the mechanistic study of gene delivery

LDL cholesterol counteracts the antitumour effect of tyrosine kinase inhibitors against renal cell carcinoma.

Science.gov (United States)

Naito, Sei; Makhov, Peter; Astsaturov, Igor; Golovine, Konstantin; Tulin, Alexei; Kutikov, Alexander; Uzzo, Robert G; Kolenko, Vladimir M

2017-04-25

Treatment with tyrosine kinase inhibitors (TKIs) significantly improves survival of patients with renal cell carcinoma (RCC). However, about one-quarter of the RCC patients are primarily refractory to treatment with TKIs. We examined viability of RCC and endothelial cells treated with low-density lipoprotein (LDL) and/or TKIs. Next, we validated the potential role of PI3K/AKT signalling in LDL-mediated TKI resistance. Finally, we examined the effect of a high-fat/high-cholesterol diet on the response of RCC xenograft tumours to sunitinib. The addition of LDL cholesterol increases activation of PI3K/AKT signalling and compromises the antitumour efficacy of TKIs against RCC and endothelial cells. Furthermore, RCC xenograft tumours resist TKIs in mice fed a high-fat/high-cholesterol diet. The ability of renal tumours to maintain their cholesterol homoeostasis may be a critical component of TKI resistance in RCC patients.

Selective intercalation of six ligands molecules in a self-assembled triple helix

NARCIS (Netherlands)

Mateos timoneda, Miguel; Kerckhoffs, J.M.C.A.; Reinhoudt, David; Crego Calama, Mercedes

2007-01-01

The addition of a ligand molecule to an artificial self-assembled triple helix leads to the selective intercalation of two hydrogen-bonded trimers in specific binding pockets. Furthermore, the triple helix suffers large conformational rearrangements in order to accommodate the ligand molecules in a

Development of a Tumour Growth Inhibition Model to Elucidate the Effects of Ritonavir on Intratumoural Metabolism and Anti-tumour Effect of Docetaxel in a Mouse Model for Hereditary Breast Cancer.

Science.gov (United States)

Yu, Huixin; Hendrikx, Jeroen J M A; Rottenberg, Sven; Schellens, Jan H M; Beijnen, Jos H; Huitema, Alwin D R

2016-03-01

In a mouse tumour model for hereditary breast cancer, we previously explored the anti-cancer effects of docetaxel, ritonavir and the combination of both and studied the effect of ritonavir on the intratumoural concentration of docetaxel. The objective of the current study was to apply pharmacokinetic (PK)-pharmacodynamic (PD) modelling on this previous study to further elucidate and quantify the effects of docetaxel when co-administered with ritonavir. PK models of docetaxel and ritonavir in plasma and in tumour were developed. The effect of ritonavir on docetaxel concentration in the systemic circulation of Cyp3a knock-out mice and in the implanted tumour (with inherent Cyp3a expression) was studied, respectively. Subsequently, we designed a tumour growth inhibition model that included the inhibitory effects of both docetaxel and ritonavir. Ritonavir decreased docetaxel systemic clearance with 8% (relative standard error 0.4%) in the co-treated group compared to that in the docetaxel only-treated group. The docetaxel concentration in tumour tissues was significantly increased by ritonavir with mean area under the concentration-time curve 2.5-fold higher when combined with ritonavir. Observed tumour volume profiles in mice could be properly described by the PK/PD model. In the co-treated group, the enhanced anti-tumour effect was mainly due to increased docetaxel tumour concentration; however, we demonstrated a small but significant anti-tumour effect of ritonavir addition (p value effect observed when docetaxel is combined with ritonavir is mainly caused by enhanced docetaxel tumour concentration and to a minor extent by a direct anti-tumour effect of ritonavir.

Classifying the mechanisms of electrochemical shock in ion-intercalation materials

OpenAIRE

Woodford, William; Carter, W. Craig; Chiang, Yet-Ming

2014-01-01

“Electrochemical shock” – the electrochemical cycling-induced fracture of materials – contributes to impedance growth and performance degradation in ion-intercalation batteries, such as lithium-ion. Using a combination of micromechanical models and acoustic emission experiments, the mechanisms of electrochemical shock are identified, classified, and modeled in targeted model systems with different composition and microstructure. A particular emphasis is placed on mechanical degradation occurr...

Enhanced anti-HIV-1 activity of G-quadruplexes comprising locked nucleic acids and intercalating nucleic acids

DEFF Research Database (Denmark)

Pedersen, Erik Bjerregaard; Nielsen, Jakob Toudahl; Nielsen, Claus

2011-01-01

Two G-quadruplex forming sequences, 50-TGGGAG and the 17-mer sequence T30177, which exhibit anti-HIV-1 activity on cell lines, were modified using either locked nucleic acids (LNA) or via insertions of (R)-1-O-(pyren-1-ylmethyl)glycerol (intercalating nucleic acid, INA) or (R)-1-O-[4-(1......-pyrenylethynyl)phenylmethyl]glycerol (twisted intercalating nucleic acid, TINA). Incorporation of LNA or INA/TINA monomers provide as much as 8-fold improvement of anti-HIV-1 activity. We demonstrate for the first time a detailed analysis of the effect the incorporation of INA/TINA monomers in quadruplex forming...

Pemetrexed-carboplatin with intercalated icotinib in the treatment of patient with advanced EGFR wild-type lung adenocarcinoma

Science.gov (United States)

Xu, Tongpeng; Wu, Hao; Jin, Shidai; Min, Huang; Zhang, Zhihong; Shu, Yongqian; Wen, Wei; Guo, Renhua

2017-01-01

Abstract Rationale: Tyrosine kinase inhibitors (TKIs) are known to have greater efficacy in epidermal growth factor receptor (EGFR) mutation nonsmall cell lung cancer (NSCLC). However, about 10% of EGFR wild-type (wt) patients respond to TKIs. Patient concerns: Several strategies to increase the efficacy of TKIs in wt NSCLC are the subjects of ongoing investigations. One of them is combining EGFR TKI with intercalated chemotherapy. Diagnoses: We describe a patient with EGFR wt NSCLC, who was found with ovarian and lung metastasis, was treated with pemetrexed and intercalated icotinib. Interventions: In this case, we reported the successful long-term maintenance treatment of a patient with EGFR wt NSCLC with pemetrexed and Icotinib. The patient (40-year-old female) was found with ovarian masses and lung masses. Pathological, immunohistochemical, and amplification refractory mutation system (ARMS) assay examinations of ovarian specimen suggested the expression of metastatic lung adenocarcinoma with wt EGFR. After failure treatment with paclitaxel-carboplatin, the patient received 4 cycles of pemetrexed plus platinum with intercalated icotinib and then remained on pemetrexed and icotinib. Outcomes: A partial response was achieved after the treatment. The patient's condition had remained stable on pemetrexed and icotinib for more than 20 months, with no evidence of progression. Lessons: To our knowledge, this is the first report using the long-term maintenance treatment with pemetrexed and intercalated icotinib in EGFR wt patient. The therapeutic strategies warrant further exploration in selected populations of NSCLC. PMID:28816950

Synchrotron-Radiation X-Ray Investigation of Li+/Na+ Intercalation into Prussian Blue Analogues

Directory of Open Access Journals (Sweden)

Yutaka Moritomo

2013-01-01

Full Text Available Prussian blue analogies (PBAs are promising cathode materials for lithium ion (LIB and sodium ion (SIB secondary batteries, reflecting their covalent and nanoporous host structure. With use of synchrotron-radiation (SR X-ray source, we investigated the structural and electronic responses of the host framework of PBAs against Li+ and Na+ intercalation by means of the X-ray powder diffraction (XRD and X-ray absorption spectroscopy (XAS. The structural investigation reveals a robust nature of the host framework against Li+ and Na+ intercalation, which is advantageous for the stability and lifetime of the batteries. The spectroscopic investigation identifies the redox processes in respective plateaus in the discharge curves. We further compare these characteristics with those of the conventional cathode materials, such as, LiCoO2, LiFePO4, and LiMn2O4.

Electron Beam Irradiated Intercalated CNT Yarns For Aerospace Applications

Science.gov (United States)

Waters, Deborah L.; Gaier, James R.; Williams, Tiffany S.; Lopez Calero, Johnny E.; Ramirez, Christopher; Meador, Michael A.

2015-01-01

Multi-walled CNT yarns have been experimentally and commercially created to yield lightweight, high conductivity fibers with good tensile properties for application as electrical wiring and multifunctional tendons. Multifunctional tendons are needed as the cable structures in tensegrity robots for use in planetary exploration. These lightweight robust tendons can provide mechanical strength for movement of the robot in addition to power distribution and data transmission. In aerospace vehicles, such as Orion, electrical wiring and harnessing mass can approach half of the avionics mass. Use of CNT yarns as electrical power and data cables could reduce mass of the wiring by thirty to seventy percent. These fibers have been intercalated with mixed halogens to increase their specific electrical conductivity to that near copper. This conductivity, combined with the superior strength and fatigue resistance makes it an attractive alternative to copper for wiring and multifunctional tendon applications. Electron beam irradiation has been shown to increase mechanical strength in pristine CNT fibers through increased cross-linking. Both pristine and intercalated CNT yarns have been irradiated using a 5-megavolt electron beam for various durations and the conductivities and tensile properties will be discussed. Structural information obtained using a field emission scanning electron microscope, energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy will correlate microstructural details with bulk properties.

Impact of Infralimbic Inputs on Intercalated Amygdale Neurons: A Biophysical Modeling Study

Science.gov (United States)

Li, Guoshi; Amano, Taiju; Pare, Denis; Nair, Satish S.

2011-01-01

Intercalated (ITC) amygdala neurons regulate fear expression by controlling impulse traffic between the input (basolateral amygdala; BLA) and output (central nucleus; Ce) stations of the amygdala for conditioned fear responses. Previously, stimulation of the infralimbic (IL) cortex was found to reduce fear expression and the responsiveness of Ce…

Disturbed Desmoglein-2 in the intercalated disc of pediatric patients with dilated cardiomyopathy

NARCIS (Netherlands)

Kessler, Elise L.; Nikkels, Peter GJ; van Veen, Toon AB

2017-01-01

Dilated cardiomyopathy (DCM) leads to disturbed contraction and force transduction, and is associated with substantial mortality in all age groups. Involvement of a disrupted composition of the intercalated disc (ID) has been reported. However, in children, little is established about such

Ge-intercalated graphene: The origin of the p-type to n-type transition

KAUST Repository

Kaloni, Thaneshwor P.; Kahaly, M. Upadhyay; Cheng, Yingchun; Schwingenschlö gl, Udo

2012-01-01

deposition on the surface; and iii) cluster intercalation. All other configurations under study result in p-type states irrespective of the Ge coverage. We explain the origin of the different doping states and establish the conditions under which a transition

Perturbation of the Electron Transport Mechanism by Proton Intercalation in Nanoporous TiO2 Films

Energy Technology Data Exchange (ETDEWEB)

Halverson, A. F.; Zhu, K.; Erslev, P. T.; Kim, J. Y.; Neale, N. R.; Frank, A. J.

2012-04-11

This study addresses a long-standing controversy about the electron-transport mechanism in porous metal oxide semiconductor films that are commonly used in dye-sensitized solar cells and related systems. We investigated, by temperature-dependent time-of-flight measurements, the influence of proton intercalation on the electron-transport properties of nanoporous TiO{sub 2} films exposed to an ethanol electrolyte containing different percentages of water (0-10%). These measurements revealed that increasing the water content in the electrolyte led to increased proton intercalation into the TiO{sub 2} films, slower transport, and a dramatic change in the dependence of the thermal activation energy (E{sub a}) of the electron diffusion coefficient on the photogenerated electron density in the films. Random walk simulations based on a microscopic model incorporating exponential conduction band tail (CBT) trap states combined with a proton-induced shallow trap level with a long residence time accounted for the observed effects of proton intercalation on E{sub a}. Application of this model to the experimental results explains the conditions under which E{sub a} dependence on the photoelectron density is consistent with multiple trapping in exponential CBT states and under which it appears at variance with this model.

Phosphate removal from water using lithium intercalated gibbsite.

Science.gov (United States)

Wang, Shan-Li; Cheng, Chia-Yi; Tzou, Yu-Min; Liaw, Ren-Bao; Chang, Ta-Wei; Chen, Jen-Hshuan

2007-08-17

In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl2(OH)6]+ layers with interlayer Cl- and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g(-1) at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl- ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H(2)PO(4)(-)/HPO4(2-) molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1M. The adsorption at higher pH showed high selectivity toward divalent HPO4(2-) ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water.

Phosphate removal from water using lithium intercalated gibbsite

International Nuclear Information System (INIS)

Wang, S.-L.; Cheng, C.-Y.; Tzou, Y.-M.; Liaw, R.-B.; Chang, T.-W.; Chen, J.-H.

2007-01-01

In this study, lithium intercalated gibbsite (LIG) was investigated for its effectiveness at removing phosphate from water and the mechanisms involved. LIG was prepared through intercalating LiCl into gibbsite giving a structure of [LiAl 2 (OH) 6 ] + layers with interlayer Cl - and water. The results of batch adsorption experiments showed that the adsorption isotherms at various pHs exhibited an L-shape and could be fitted well using the Langmuir model. The Langmuir adsorption maximum was determined to be 3.0 mmol g -1 at pH 4.5 and decreased with increasing pH. The adsorption of phosphate was mainly through the displacement of the interlayer Cl - ions in LIG. In conjunction with the anion exchange reaction, the formation of surface complexes or precipitates could also readily occur at lower pH. The adsorption decreased with increasing pH due to decreased H 2 PO 4 - /HPO 4 2- molar ratio in solution and positive charges on the edge faces of LIG. Anion exchange is a fast reaction and can be completed within minutes; on the contrary, surface complexation is a slow process and requires days to reach equilibrium. At lower pH, the amount of adsorbed phosphate decreased significantly as the ionic strength was increased from 0.01 to 0.1 M. The adsorption at higher pH showed high selectivity toward divalent HPO 4 2- ions with an increase in ionic strength having no considerable effect on the phosphate adsorption. These results suggest that LIG may be an effective scavenger for removal of phosphate from water

Effect of molecular intercalation on the local structure of superconducting Nax(NH3)yMoSe2 system

Science.gov (United States)

Simonelli, L.; Paris, E.; Wakita, T.; Marini, C.; Terashima, K.; Miao, X.; Olszewski, W.; Ramanan, N.; Heinis, D.; Kubozono, Y.; Yokoya, T.; Saini, N. L.

2017-12-01

We have studied the local structure of layered Nax(NH3)yMoSe2 system by Mo K-edge extended X-ray absorption fine structure (EXAFS) measurements performed as a function of temperature. We find that molecular intercalation in MoSe2 largely affects the Mo-Se network while Mo-Mo seems to sustain small changes. The Einstein temperature (ΘE) of Mo-Mo distance hardly changes (∼264 K) indicating that bond strength of this distance remains unaffected by intercalation. On the other hand, Mo-Se distance suffers a softening, revealed by the decrease of ΘE from ∼364 K to ∼350 K. The results indicate that Na+ ion transported by NH3 molecules may enter between the two MoSe-layers resulting reduced Se-Se coupling. Therefore, increased hybridization between Se 4p and Mo 4d orbitals due to inter-layer disorder is the likely reason of metallicity in intercalated MoSe2 and superconductivity at low temperature.

Protein intercalation in DNA as one of main modes of fixation of the most stable chromatin loop domains

Directory of Open Access Journals (Sweden)

М. I. Chopei

2014-08-01

Full Text Available The main mechanism of DNA track formation during comet assay of nucleoids, obtained after removal of cell membranes and most of proteins, is the extension to anode of negatively supercoiled DNA loops attached to proteins, remaining in nucleoid after lysis treatment. The composition of these residual protein structures and the nature of their strong interaction with the loop ends remain poorly studied. In this work we investigated the influence of chloroquine intercalation and denaturation of nucleoid proteins on the efficiency of electrophoretic track formation during comet assay. The results obtained suggest that even gentle protein denaturation is sufficient to reduce considerably the effectiveness of the DNA loop migration due to an increase in the loops size. The same effect was observed under local DNA unwinding upon chloroquine intercalation around the sites of the attachment of DNA to proteins. The topological interaction (protein intercalation into the double helix between DNA loop ends and nucleoid proteins is discussed.

Increasing the analytical sensitivity by oligonucleotides modified with para- and ortho-twisted intercalating nucleic acids--TINA.

Directory of Open Access Journals (Sweden)

Uffe V Schneider

Full Text Available The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5' and 3' termini (preferable or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide, with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ΔTm, unless placed directly adjacent to the mismatch--in which case they partly concealed ΔTm (most pronounced for para-TINA molecules. We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems.

DNA intercalation studies and antimicrobial activity of Ag@ZrO{sub 2} core–shell nanoparticles in vitro

Energy Technology Data Exchange (ETDEWEB)

Dhanalekshmi, K.I., E-mail: dhanamveni88@gmail.com; Meena, K.S.

2016-02-01

Ag@ZrO{sub 2} core–shell nanoparticles were prepared by one pot simultaneous reduction of AgNO{sub 3} and hydrolysis of zirconium (IV) isopropoxide. The formation of core–shell nanoparticles was confirmed by absorption, XRD, and HR-TEM techniques. The antibacterial activity of Ag@ZrO{sub 2} core–shell nanoparticles against Escherichia coli and Staphylococcus aureus and the antifungal properties against Candida albicans, Candida glabrata, Aspergillus niger and Aspergillus flavus were examined by the agar diffusion method. DNA intercalation studies were carried out in CT-DNA. As a result ZrO{sub 2} supported on the surface of AgNPs not only prevented aggregation, but also proved to have enhanced antimicrobial activity and DNA intercalation than the Ag nanoparticles. - Highlights: • Ag@ZrO{sub 2} core–shell nanoparticles were prepared by one pot synthesis. • The ZrO{sub 2} coated AgNPs prevent aggregation and enhanced stability. • The surfaced modified AgNPs showed higher antimicrobial activity. • DNA intercalation studies show better binding affinity of core–shell NPs.

Physical properties of C60 intercalated graphite films

International Nuclear Information System (INIS)

Nakahara, T; Hosomi, N; Taniguchi, J; Suzuki, M; Sato, T; Abe, K; Kuwahara, D; Ishikawa, M; Kato, M; Miura, K

2007-01-01

Recently, Miura and Tsuda have synthesized C 60 intercalated graphite film (C 60 /Gr) and reported that the C 60 /Gr consists of alternating close-packed C 60 monolayers and graphite layers. They also found that its frictional force is minimal up to the loading force of 100 nN using AFM [Miura K and Tsuda D 2005 e-J. Surf. Sci. Nanotech. 3 21] Thus, we have started to study the physical properties of C 60 /Gr and carried out NMR, Raman scattering and specific heat measurements. These results suggest that C 60 in C 60 /Gr rotates at room temperature

Noncovalent DNA Binding Drives DNA Alkylation by Leinamycin. Evidence That the Z,E-5-(Thiazol-4-yl)-penta-2,4-dienone Moiety of the Natural Product Serves As An Atypical DNA Intercalator

Science.gov (United States)

Fekry, Mostafa I.; Szekely, Jozsef; Dutta, Sanjay; Breydo, Leonid; Zang, Hong; Gates, Kent S.

2012-01-01

Molecular recognition and chemical modification of DNA are important in medicinal chemistry, toxicology, and biotechnology. Historically, natural products have revealed many interesting and unexpected mechanisms for noncovalent DNA binding and covalent DNA modification. The studies reported here characterize the molecular mechanisms underlying the efficient alkylation of duplex DNA by the Streptomyces-derived natural product leinamycin. Previous studies suggested that alkylation of duplex DNA by activated leinamycin (2) is driven by noncovalent association of the natural product with the double helix. This is striking because leinamycin does not contain a classical noncovalent DNA-binding motif such as an intercalating unit, a groove binder, or a polycation. The experiments described here provide evidence that leinamycin is an atypical DNA-intercalating agent. A competition binding assay involving daunomycin-mediated inhibition of DNA alkylation by leinamycin provided evidence that activated leinamycin binds to duplex DNA with an apparent binding constant of approximately 4.3 ± 0.4 × 103 M−1. Activated leinamycin caused duplex unwinding and hydrodynamic changes in DNA-containing solutions that are indicative of DNA intercalation. Characterization of the reaction of activated leinamycin with palindromic duplexes containing 5'-CG and 5'-GC target sites, bulge-containing duplexes, and 5-methylcytosine-containing duplexes provided evidence regarding the orientation of leinamycin with respect to target guanine residues. The data allows construction of a model for the leinamycin-DNA complex suggesting how a modest DNA-binding constant combines with proper positioning of the natural product to drive efficient alkylation of guanine residues in the major groove of duplex DNA. PMID:21954957

Anti-tumour activity in RAS-driven tumours by blocking AKT and MEK

Science.gov (United States)

Tolcher, Anthony W.; Khan, Khurum; Ong, Michael; Banerji, Udai; Papadimitrakopoulou, Vassiliki; Gandara, David R.; Patnaik, Amita; Baird, Richard D.; Olmos, David; Garrett, Christopher R.; Skolnik, Jeffrey M.; Rubin, Eric H.; Smith, Paul D.; Huang, Pearl; Learoyd, Maria; Shannon, Keith A.; Morosky, Anne; Tetteh, Ernestina; Jou, Ying-Ming; Papadopoulos, Kyriakos P.; Moreno, Victor; Kaiser, Brianne; Yap, Timothy A.; Yan, Li; de Bono, Johann S.

2014-01-01

Purpose KRAS is the most commonly mutated oncogene in human tumours. KRAS-mutant cells may exhibit resistance to the allosteric MEK1/2 inhibitor selumetinib (AZD6244; ARRY-142886) and allosteric AKT inhibitors (such as MK-2206), the combination of which may overcome resistance to both monotherapies. Experimental Design We conducted a dose/schedule-finding study evaluating MK-2206 and selumetinib in patients with advanced treatment-refractory solid tumours. Recommended dosing schedules were defined as MK-2206 135 mg weekly and selumetinib 100 mg once-daily. Results Grade 3 rash was the most common dose-limiting toxicity (DLT); other DLTs included grade 4 lipase increase, grade 3 stomatitis, diarrhoea, and fatigue, and grade 3 and grade 2 retinal pigment epithelium detachment. There were no meaningful pharmacokinetic drug-drug interactions. Clinical anti-tumour activity included RECIST 1.0-confirmed partial responses in non-small cell lung cancer and low-grade ovarian carcinoma. Conclusion Responses in KRAS-mutant cancers were generally durable. Clinical co-targeting of MEK and AKT signalling may be an important therapeutic strategy in KRAS-driven human malignancies (Trial NCT number NCT01021748). PMID:25516890

Lipoprotein Nanoplatform for Targeted Delivery of Diagnostic and Therapeutic Agents

Directory of Open Access Journals (Sweden)

Jerry D. Glickson

2008-03-01

Full Text Available Low-density lipoprotein (LDL provides a highly versatile natural nanoplatform for delivery of visible or near-infrared fluorescent optical and magnetic resonance imaging (MRI contrast agents and photodynamic therapy and chemotherapeutic agents to normal and neoplastic cells that overexpress low-density lipoprotein receptors (LDLRs. Extension to other lipoproteins ranging in diameter from about 10 nm (high-density lipoprotein [HDL] to over a micron (chylomicrons is feasible. Loading of contrast or therapeutic agents onto or into these particles has been achieved by protein loading (covalent attachment to protein side chains, surface loading (intercalation into the phospholipid monolayer, and core loading (extraction and reconstitution of the triglyceride/cholesterol ester core. Core and surface loading of LDL have been used for delivery of optical imaging agents to tumor cells in vivo and in culture. Surface loading was used for delivery of gadolinium-bis-stearylamide contrast agents for in vivo MRI detection in tumor-bearing mice. Chlorin and phthalocyanine near-infrared photodynamic therapy agents (≤ 400/LDL have been attached by core loading. Protein loading was used to reroute the LDL from its natural receptor (LDLR to folate receptors and could be used to target other receptors. A semisynthetic nanoparticle has been constructed by coating magnetite iron oxide nanoparticles with carboxylated cholesterol and overlaying a monolayer of phospholipid to which apolipoprotein A1 or E was adsorbed for targeting HDL or adsorbing synthetic amphipathic helical peptides ltargeting LDL or folate receptors. These particles can be used for in situ loading of magnetite into cells for MRI-monitored cell tracking or gene expression.

Simultaneous Intercalation of 1-Naphthylacetic Acid and Indole-3-butyric Acid into Layered Double Hydroxides and Controlled Release Properties

Directory of Open Access Journals (Sweden)

Shifeng Li

2014-01-01

Full Text Available Controlled release formulations have been shown to have potential in overcoming the drawbacks of conventional plant growth regulators formulations. A controlled-release formulation of 1-naphthylacetic acid (NAA and indole-3-butyric acid (IBA simultaneous intercalated MgAl-layered double hydroxides (LDHs was prepared. The synthetic nanohybrid material was characterized by various techniques, and release kinetics was studied. NAA and IBA anions located in the gallery of MgAl-LDHs with bilayer arrangement, and the nanohybrids particles were of typical plate-like shape with the lateral size of 50–100 nm. The results revealed that NAA and IBA have been intercalated into the interlayer spaces of MgAl-LDHs. The release of NAA and IBA fits pseudo-second-order model and is dependent on temperature, pH value, and release medium. The nanohybrids of NAA and IBA simultaneously intercalated in LDHs possessed good controlled release properties.

Preparation and characterization of lactate-intercalated Co–Fe layered double hydroxides and exfoliated nanosheet film with low infrared emissivity

International Nuclear Information System (INIS)

Zhu Yunxia; Zhou Yuming; Zhang Tao; He Man; Wang Yongjuan; Yang Xiaoming; Yang Yong

2012-01-01

Highlights: ► We use ferrous, cobalt powders and lactic acid to synthesis lactate-intercalated Co–Fe layered double hydroxides successfully. ► A possible orientation of the intercalated lactate between the layers is carried out. ► The thin nanosheet film is fabricated and the surface is very smooth and flat. ► The infrared emissivity value of Co–Fe LDHs is lower than that of Zn–Al or Mg–Al LDHs, and the value is further reduced after forming a thin film. - Abstract: Lactate-intercalated Co–Fe layered double hydroxides (LDHs) were successfully prepared by coprecipitation and hydrothermal method. In this process, divalent metal ions as precursors can be obtained from the reduction reaction of lactic acid and metal powder (cobalt and ferrous). In order to obtain Fe 3+ , H 2 O 2 (30%) was used to oxidize Fe 2+ . Meanwhile, the produced lactate was intercalated into the LDHs interlayers to compensate the positively charged layers. The as-synthesized LDHs were studied by element chemical analysis, powder X-ray diffraction (XRD), FT-IR spectroscopy, thermogravitry (TG) and differential scanning calorimetry (DSC), TEM. The results indicated that the basal spacing value of the LDHs was larger than that of lactate-intercalated Mg–Al or Zn–Al LDHs. It proved that the lactate anions were inserted into the gallery in the form of dimers which made it easy to be delaminated in water. The obtained nanosheets were deposited on the substrates to form the film which was characterized by TEM and AFM, and infrared emissivity value (8–14 μm) was also investigated. The infrared emissivity values of Co–Fe LDHs were lower than that of Zn–Al which took advantage of the special electronic structure in Co and Fe. Besides, the orderly structure and the reduction of the interfacial deficiency of the film made the values further reduced.

Synthesis and antitumour activity of arctigenin amino acid ester derivatives against H22 hepatocellular carcinoma.

Science.gov (United States)

Cai, Enbo; Guo, Shijie; Yang, Limin; Han, Mei; Xia, Jing; Zhao, Yan; Gao, Xiaorui; Wang, Yu

2018-02-01

Arctigenin (ARG) is famous in its abundant pharmacological activity. However, many researches in it entered the bottleneck period because of its poor water solubility. The derivatives of ARG have been synthesised with five amino acids which have t-Butyloxy carbonyl (BOC) as a protective group. We examined the effects of removing BOC. The results showed that the amino acid derivatives without protective group have better water solubility and nitrite-clearing ability than ARG. Based on these results, ARG6' and ARG9' were selected at a dosage of 40 mg/kg to evaluate their antitumour activity. The percentage inhibition rate of ARG6' and ARG9' were 55.87 and 51.40, respectively, which was twice as much as ARG. Furthermore, they could increase liver and kidney indexes and produce less damage in these organs. In brief, this study provides a basis for new drug development.

Synthesis of Mn-intercalated layered titanate by exfoliation–flocculation approach and its efficient photocatalytic activity under visible–light

International Nuclear Information System (INIS)

Fu, Jie; Tian, Yanlong; Chang, Binbin; Li, Gengnan; Xi, Fengna; Dong, Xiaoping

2012-01-01

A novel Mn-intercalated layered titanate as highly active photocatalyst in visible-light region has been synthesized via a convenient and efficient exfoliation–flocculation approach with divalent Mn ions and monolayer titanate nanosheets. The 0.91 nm interlayer spacing of obtained photocatalyst is in accordance with the sum of the thickness of titanate nanosheet and the diameter of Mn ions. The yellow photocatalyst shows a spectral response in visible-light region and the calculated band gap is 2.59 eV. The photocatalytic performance of this material was evaluated by degradation and mineralization of an aqueous dye methylene blue under visible-light irradiation, and an enhanced photocatalytic activity in comparison with protonated titanate as well as the P25 TiO 2 and N-doped TiO 2 was obtained. Additionally, the layered structure is retained, no dye ions intercalating occurs during the photocatalysis process, and a ∼90% photocatalytic activity can be remained after reusing 3 cycles. - Graphical abstract: Mn-intercalated layered titanate as a novel and efficient visible-light harvesting photocatalyst was synthesized via a convenient and efficient exfoliation–flocculation approach in a mild condition. Highlights: ► Mn-intercalated titanate has been prepared by exfoliation–flocculation approach. ► The as-prepared catalyst shows spectral response in the visible-light region. ► Heat treatment at certain temperature enables formation of Mn-doped TiO 2 . ► Dye can be degradated effectively by the catalyst under visible light irradiation.

Synthesis and magnetic properties of layered MnPSxSe3-x (0 < x < 3) and corresponding intercalation compounds of 2,2'-bipyridine

International Nuclear Information System (INIS)

Yan, Xiaobing; Chen, Xingguo; Qin, Jingui

2011-01-01

Graphical abstract: A series of new layered MnPS x Se 3-x (0 x Se 3-x exhibited antiferromagnetism similar to MnPS 3 or MnPSe 3 , but the intercalation of 2,2'-bipyridine can dramatically change the properties of MnPS x Se 3-x slab. Research highlights: → A series of new MnPS x Se 3-x are designed and synthesized for the first time and their layered structure has been determined. → The intercalation chemistry has been initially studied via the intercalation of 2,2'-bipyridine with MnPS x Se 3-x . → The magnetic properties of the series MnPS x Se 3-x and the corresponding intercalation compounds of 2,2'-bipydine have been studied. And the relationship between the structure and the magnetic propertied has been primarily explored. -- Abstract: In this work, we synthesize a series of new MnPS x Se 3-x (0 1-y PS x Se 3-x (bipy) 4y , x = 1.2, 1.8 and 2.4) via the intercalation of 2,2'-bipyridine with MnPS x Se 3-x . XRD results confirm that MnPS x Se 3-x compounds show the layered structure and can be regarded as the solid solution of MnPS 3 and MnPSe 3 . Magnetic measurements indicate that MnPS x Se 3-x compounds exhibit paramagnetism with negative Weiss constant in the paramagnetic temperature region, and an antiferromagnetic phase transition occurs at the Neel temperature. It is found that the magnetic properties of MnPS x Se 3-x slab are dramatically changed after the intercalation of 2,2'-bipyridine, which is close related to the relative ratio of S and Se atom as well as the intralayered Mn 2+ vacancies of MnPS x Se 3-x slab.

Silicene on Monolayer PtSe2: From Strong to Weak Binding via NH3 Intercalation

KAUST Repository

Sattar, Shahid; Singh, Nirpendra; Schwingenschlö gl, Udo

2018-01-01

We study the properties of silicene on monolayer PtSe2 by first-principles calculations and demonstrate a much stronger interlayer interaction than previously reported for silicene on other semiconducting substrates. This fact opens the possibility of a direct growth. A band gap of 165 meV results from inversion symmetry breaking and large spin-splittings in the valence and conduction bands from proximity to monolayer PtSe2 and its strong spin–orbit coupling. It is also shown that the interlayer interaction can be effectively reduced by intercalating NH3 molecules between silicene and monolayer PtSe2 without inducing charge transfer or defect states near the Fermi energy. A small NH3 diffusion barrier makes intercalation a viable experimental approach to control the interlayer interaction.

Silicene on Monolayer PtSe2: From Strong to Weak Binding via NH3 Intercalation

KAUST Repository

Sattar, Shahid

2018-01-16

We study the properties of silicene on monolayer PtSe2 by first-principles calculations and demonstrate a much stronger interlayer interaction than previously reported for silicene on other semiconducting substrates. This fact opens the possibility of a direct growth. A band gap of 165 meV results from inversion symmetry breaking and large spin-splittings in the valence and conduction bands from proximity to monolayer PtSe2 and its strong spin–orbit coupling. It is also shown that the interlayer interaction can be effectively reduced by intercalating NH3 molecules between silicene and monolayer PtSe2 without inducing charge transfer or defect states near the Fermi energy. A small NH3 diffusion barrier makes intercalation a viable experimental approach to control the interlayer interaction.

Analysis of Charge Transfer for in Situ Li Intercalated Carbon Nanotubes

KAUST Repository

Rana, Kuldeep

2012-05-24

Vertically aligned carbon nanotube (VA-CNT) arrays have been synthesized with lithium (Li) intercalation through an alcohol-catalyzed chemical vapor deposition technique by using a Li-containing catalyst. Scanning electron microscopy images display that synthesized carbon nanotubes (CNTs) are dense and vertically aligned. The effect of the Li-containing catalyst on VA-CNTs has been studied by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS). XPS results show the change in binding energy of Li 1s and C 1s peaks, which indicates that Li is inserted in VA-CNTs during growth. Analysis of Raman spectra reveals that the G-band profile of CNTs synthesized with the Li-containing catalyst is shifted, suggesting an electronic interaction between Li and neighboring C atoms of the CNTs. The EELS spectra of the C K edge and Li K edge from CNTs also confirmed that Li is inserted into CNTs during synthesis. We have performed ab inito calculations based on density functional theory for a further understanding of the structural and electronic properties of Li intercalated CNTs, especially addressing the controversial charge-transfer state between Li and C. © 2012 American Chemical Society.

Analysis of Charge Transfer for in Situ Li Intercalated Carbon Nanotubes

KAUST Repository

Rana, Kuldeep; Kucukayan-Dogu, Gokce; Sen, H. Sener; Boothroyd, Chris; Gulseren, Oguz; Bengu, Erman

2012-01-01

Vertically aligned carbon nanotube (VA-CNT) arrays have been synthesized with lithium (Li) intercalation through an alcohol-catalyzed chemical vapor deposition technique by using a Li-containing catalyst. Scanning electron microscopy images display that synthesized carbon nanotubes (CNTs) are dense and vertically aligned. The effect of the Li-containing catalyst on VA-CNTs has been studied by using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS). XPS results show the change in binding energy of Li 1s and C 1s peaks, which indicates that Li is inserted in VA-CNTs during growth. Analysis of Raman spectra reveals that the G-band profile of CNTs synthesized with the Li-containing catalyst is shifted, suggesting an electronic interaction between Li and neighboring C atoms of the CNTs. The EELS spectra of the C K edge and Li K edge from CNTs also confirmed that Li is inserted into CNTs during synthesis. We have performed ab inito calculations based on density functional theory for a further understanding of the structural and electronic properties of Li intercalated CNTs, especially addressing the controversial charge-transfer state between Li and C. © 2012 American Chemical Society.

Functional copolymer/organo-MMT nanoarchitectures. VI. Synthesis and characterization of novel nanocomposites by interlamellar controlled/living radical copolymerization via preintercalated RAFT-agent/organoclay complexes.

Science.gov (United States)

Rzayev, Zakir M O; Söylemez, A Ernur

2011-04-01

We have developed a new approach for the synthesis of polymer nanocomposites using a bifunctional reversible addition-fragmentation chain transfer (RAFT) agent, two types of organo-montmorillonites, such as a non-reactive dimethyldodecyl ammonium (DMDA)-MMT and a reactive octadecylamine (ODA)-MMT organoclays, and a radical initiator. The method includes the following stages: (1) synthesis of RAFT intercalated O-MMTs by a physical or chemical interaction of the RAFT agent having two pendant carboxylic groups [S,S-bis(alpha,alpha'-dimethyl-alpha"-acetic acid)trithiocarbonate] with surface alkyl amines of O-MMT containing tertiary ammonium cation or primary amine groups through strong H-bonding and complexing/amidization reactions, respectively, and (2) utilization of these well-dispersed and intercalated RAFT ... O-MMT complexes and their amide derivatives as new modified RAFT agents in radical-initiated interlamellar controlled/living copolymerization of itaconic acid (IA)-n-butylmethacrylate (BMA) monomer pair. The structure and compositions of the synthesized RAFT ... O-MMT complexes and functional copolymer/O-MMT hybrids were confirmed by FTIR, XRD, thermal (DSC-TGA), SEM and TEM morphology analyses. It was demonstrated that the degree of interaction/exfoliation, morphology and thermal behavior of nanocomposites significantly depended on the type of organoclay and in situ interaction, as well as on the content of flexible butyl-ester linkages as a internal plasticizer. The results of the comparative analysis of the nanocomposites structure-composition-property relations show that the functional copolymer-organoclay hybrids prepared with reactive RAFT ... ODA-MMT complex and containing a combination of partially intercalated and predominantly exfoliated nano-structures exhibit relatively higher thermal stability and fine dispersed morphology. These effects were explained by in situ interfacial chemical reactions through amidization of RAFT with surface alkyl amine

Keggin type polyoxometalate H4[αSiW12O40].nH2O as intercalant for hydrotalcite

Directory of Open Access Journals (Sweden)

Neza Rahayu Palapa

2017-06-01

Full Text Available The synthesis of hydrotalcite and polyoxometalate H4[αSiW12O40].nH2O with the ratio (2:1, (1:1, (1:2 and (1:3 has been done. The product of intercalation was characterized using FT-IR spectrophotometer, XRD, and TG-DTA. Polyoxometalate H4[αSiW12O40].nH2O intercalated layered double hydroxide was optimised to use as adsorbent Congo red dye. Characterization using FT-IR was not showing the optimal insertion process. The result using XRD characterization was showed successful of polyoxometalate H4[αSiW12O40].nH2O inserted layered double hydroxide with a ratio (1:1 which the basal spacing was expanded from 7,8 Ȧ to 9,81 Ȧ. Furthermore, the thermal analysis was performed using TG-DTA. The result show that the decomposition of polyoxometalate H4[αSiW12O40].nH2O intercalated  hydrotalcite with ratio (1:1 was occured at 80oC to 400oC with a loss of OH in the layer at 150oC to 220oC, and then the decomposition of the compound polyoxometalate H4[αSiW12O40].nH2O at 350oC to 420oC. Keywords: Hydrotalcite, Layered Double Hydroxide, Polyoxometalate, Intercalation

Staging structures of the intercalation compounds Ag/sub x/TiS2

International Nuclear Information System (INIS)

Bardhan, K.K.; Kirczenow, G.; Jackle, G.; Irwin, J.C.

1986-01-01

An extensive investigation of the structure, and in particular the staging, of powdered samples of the intercalation compounds Ag/sub x/TiS 2 (0 0 C. The (T,x) phase diagram contains three phases: a high-x (dense) stage-1 phase, a stage-disordered phase, which at low x or high temperatures appears to become a pure low-x (dilute) stage-1 phase, and a simple stage-2 phase. On the high-x side of its stability region the stage-2 phase undergoes an apparent first-order transition to the dense stage-1 phase, but on the high-temperature side it proceeds continuously, through stage-disordered states, to a dilute stage-1 phase. On the low-x side of the stage-2 region there is also a dilute stage-1 phase. At sufficiently high temperatures a novel coexistence of the two stage-1 phases is observed. This is the first time that the high-temperature stability limit of the stage-2 region has been probed in any intercalation compound. The results are compared with recent theoretical models

Uniform second Li ion intercalation in solid state ϵ-LiVOPO4

International Nuclear Information System (INIS)

Wangoh, Linda W.; Quackenbush, Nicholas F.; Sallis, Shawn; Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W.; Lin, Yuh-Chieh; Ong, Shyue Ping; Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley; Guo, Jinghua; Lee, Tien-Lin; Schlueter, Christoph; Piper, Louis F. J.

2016-01-01

Full, reversible intercalation of two Li + has not yet been achieved in promising VOPO 4 electrodes. A pronounced Li + gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO 4 cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li + gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li + intercalation is a prerequisite for the formation of intermediate phases Li 1.50 VOPO 4 and Li 1.75 VOPO 4 . The evolution from LiVOPO 4 to Li 2 VOPO 4 via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

Functional intercalated nanocomposites with chitosan-glutathione-glycylsarcosine and layered double hydroxides for topical ocular drug delivery.

Science.gov (United States)

Xu, Tingting; Xu, Xiaoyue; Gu, Yan; Fang, Lei; Cao, Feng

2018-01-01

To enhance ocular bioavailability, the traditional strategies have focused on prolonging precorneal retention and improving corneal permeability by nano-carriers with positive charge, thiolated polymer, absorption enhancer and so on. Glycylsarcosine (GS) as an active target ligand of the peptide tranpsporter-1 (PepT-1), could specific interact with the PepT-1 on the cornea and guide the nanoparticles to the treating site. The objective of the study was to explore the active targeting intercalated nanocomposites based on chitosan-glutathione-glycylsarcosine (CG-GS) and layered double hydroxides (LDH) as novel carriers for the treatment of mid-posterior diseases. CG-GS-LDH intercalated nanocomposites were prepared by the coprecipitation hydrothermal method. In vivo precorneal retention study, ex vivo fluorescence images, in vivo experiment for distribution and irritation were studied in rabbits. The cytotoxicity and cellular uptake were studied in human corneal epithelial primary cells (HCEpiC). CG-GS-LDH nanocomposites were prepared successfully and characterized by FTIR and XRD. Experiments with rabbits showed longer precorneal retention and higher distribution of fluorescence probe/model drug. In vitro cytological study, CG-GS-LDH nanocomposites exhibited enhanced cellular uptake compared to pure drug solution. Furthermore, the investigation of cellular uptake mechanisms demonstrated that both the active transport by PepT-1 and clathrin-mediated endocytosis were involved in the internalization of CG-GS-LDH intercalated nanocomposites. An ocular irritation study and a cytotoxicity test indicated that these nanocomposites produced no significant irritant effects. The active targeting intercalated nanocomposites could have great potential for topical ocular drug delivery due to the capacity for prolonging the retention on the ocular surface, enhancing the drug permeability through the cornea, and efficiently delivering the drug to the targeted site.

One-step synthesis of graphene/polyaniline hybrids by in situ intercalation polymerization and their electromagnetic properties

Science.gov (United States)

Chen, Xiangnan; Meng, Fanchen; Zhou, Zuowan; Tian, Xin; Shan, Liming; Zhu, Shibu; Xu, Xiaoling; Jiang, Man; Wang, Li; Hui, David; Wang, Yong; Lu, Jun; Gou, Jihua

2014-06-01

A new method is introduced for the preparation of graphene/polyaniline hybrids using a one-step intercalation polymerization of aniline inside the expanded graphite. The structural and morphological characterizations were performed by X-ray diffraction analysis, transmission electron microscopy and field emission scanning electron microscopy. Both the experimental and first-principles simulated results show that the aniline cation formed by aniline and H+ tends to be drawn towards the electron-enriched zone and to intercalate into the interlayer of graphite. Subsequently, an in situ polymerization leads to the separation of graphite into graphene sheet, resulting from the exothermic effect and more vigorous movements of the chain molecules of polyaniline. The interactions between polyaniline and graphene were confirmed by Fourier transform infrared spectroscopy and Raman spectra. In addition, the graphene/polyaniline hybrid exhibited a breakthrough in the improvement of microwave absorption.A new method is introduced for the preparation of graphene/polyaniline hybrids using a one-step intercalation polymerization of aniline inside the expanded graphite. The structural and morphological characterizations were performed by X-ray diffraction analysis, transmission electron microscopy and field emission scanning electron microscopy. Both the experimental and first-principles simulated results show that the aniline cation formed by aniline and H+ tends to be drawn towards the electron-enriched zone and to intercalate into the interlayer of graphite. Subsequently, an in situ polymerization leads to the separation of graphite into graphene sheet, resulting from the exothermic effect and more vigorous movements of the chain molecules of polyaniline. The interactions between polyaniline and graphene were confirmed by Fourier transform infrared spectroscopy and Raman spectra. In addition, the graphene/polyaniline hybrid exhibited a breakthrough in the improvement of

Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study

Science.gov (United States)

Crasto de Lima, F. D.; Miwa, R. H.; Miranda, Caetano R.

2017-11-01

Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ˜20 and ˜130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.

Superconductivity in intercalated and substituted Y2Br2C2

International Nuclear Information System (INIS)

Baecker, M.; Simon, A.; Kremer, R.K.; Mattausch, H.J.; Dronskowski, R.; Rouxel, J.

1996-01-01

Layer compounds of the type Y 2 X 2 C 2 (X=Cl, Br, I) show superconductivity at temperatures between 2.3 and 11.2 K. The transition temperature is related to the tendency of conduction electrons toward pairwise localization in C 2 -π * states at the Fermi level, and changes with the concentration of valence electrons, which is varied by intercalation of Na. (orig.)

Neutron scattering investigation of layer-bending modes in alkali-metal--graphite intercalation compounds

International Nuclear Information System (INIS)

Zabel, H.; Kamitakahara, W.A.; Nicklow, R.M.

1982-01-01

Phonon dispersion curves for low-frequency transverse modes propagating in the basal plane have been measured in the alkali-metal--graphite intercalation compounds KC 8 , CsC 8 , KC 24 , and RbC 24 by means of neutron spectroscopy. The acoustic branches show an almost quadratic dispersion relation at small q, characteristic of strongly layered materials. The optical branches of stage-1 compounds can be classified as either graphitelike branches showing dispersion, or as almost dispersionless alkali-metal-like modes. Macroscopic shear constants C 44 and layer-bending moduli have been obtained for the intercalation compounds by analyzing the data in terms of a simple semicontinuum model. In stage-2 compounds, a dramatic softening of the shear constant by about a factor of 8 compared with pure graphite has been observed. Low-temperature results on KC 24 indicate the opening of a frequency gap near the alkali-metal Brillouin-zone boundary, possibly due to the formation of the alkali-metal superstructure

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

KAUST Repository

Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R.; Smith, Raymond B.; Bartelt, Norman C.; Sugar, Joshua D.; Fenton, Kyle R.; Cogswell, Daniel A.; Kilcoyne, A. L. David; Tyliszczak, Tolek; Bazant, Martin Z.; Chueh, William C.

2014-01-01

©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes.

Science.gov (United States)

Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R; Smith, Raymond B; Bartelt, Norman C; Sugar, Joshua D; Fenton, Kyle R; Cogswell, Daniel A; Kilcoyne, A L David; Tyliszczak, Tolek; Bazant, Martin Z; Chueh, William C

2014-12-01

Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

KAUST Repository

Li, Yiyang

2014-09-14

©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

Production of polyol carbonates and their intercalation into Smectite clays

OpenAIRE

Shaheen, Uzma

2017-01-01

In hyper-saline conditions, clays in geosynthetic clay liners contract and fail to form a hydraulic barrier due to removal of water from the interlayer spaces of smectite, which is the swelling mineral component of bentonites used in geosynthetic clay liners. Five-membered cyclic carbonates such as propylene carbonate have been reported to form stable intercalated complexes with hydrated Na-smectite, which maintain swollen states at 1M). Glycerol carbonate was selected as an alternative c...

DNA intercalator stimulates influenza transcription and virus replication

Directory of Open Access Journals (Sweden)

Poon Leo LM

2011-03-01

Full Text Available Abstract Influenza A virus uses its host transcription machinery to facilitate viral RNA synthesis, an event that is associated with cellular RNA polymerase II (RNAPII. In this study, various RNAPII transcription inhibitors were used to investigate the effect of RNAPII phosphorylation status on viral RNA transcription. A low concentration of DNA intercalators, such as actinomycin D (ActD, was found to stimulate viral polymerase activity and virus replication. This effect was not observed in cells treated with RNAPII kinase inhibitors. In addition, the loss of RNAPIIa in infected cells was due to the shift of nonphosphorylated RNAPII (RNAPIIa to hyperphosphorylated RNAPII (RNAPIIo.

Preparation of Mg/Al-LDHs intercalated with dodecanoic acid and investigation of its antiwear ability

International Nuclear Information System (INIS)

Zhao, Dong; Bai, Zhimin; Zhao, Fuyan

2012-01-01

Graphical abstract: Comparable studies of nano Mg/Al-LDHs powder on the anti-wear properties of lubricating oil were carried out on four-ball and gear testing machine. Mg/Al-NO 3 − -LDHs and Mg/Al-DA-LDHs powder in base oil possess an excellent friction-reducing property, with a friction coefficient at 23.9% and 22.2% which are lower than that of the base oil Highlights: ► We synthesized nano Mg/Al-NO 3 − (DA)-LDHs via coprecipitation and anion exchange. ► The optimal exchanging condition is as follows: water dispersion and pH value of 5. ► The tribological properties of LDHs were studied on four-ball and gear machine. ► We reported nano LHDs as anti-wear materials in lubricates for the first time. ► The greatest decline in friction coefficient of lubricates with LDHs is up to 23.9%. -- Abstract: Layered double hydroxides (LDHs) intercalated with dodecanoic acid have been prepared by anion exchange with Mg/Al-NO 3 − -LDHs as the precursor under acid condition with water and ethanol as the dispersion medium. The obtained materials were characterized by X-ray diffraction (XRD), thermogravimetric and differential thermal analyser (TG–DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and BET. Patterns of XRD and FTIR show that interlayer nitrate ions have substituted with dodecanoic acid and the gallery height has increased from 0.88 nm to 1.99 nm. The interlayer distance of the intercalated materials increases with the increase of pH value due to the different arrangement of interlayer anions. The tribological performance of LDHs precursor and intercalated LDHs in base oil were studied for the first time by using four-ball wear machine and gear testing machine. Experimental results show that the LDHs precursor and intercalated LDHs powder are excellent in friction-reducing, with decreases in friction coefficient by 23.9% and 22.2% respectively comparing with base oil.

High-rate capability of three-dimensionally ordered macroporous T-Nb2O5 through Li+ intercalation pseudocapacitance

Science.gov (United States)

Lou, Shuaifeng; Cheng, Xinqun; Wang, Long; Gao, Jinlong; Li, Qin; Ma, Yulin; Gao, Yunzhi; Zuo, Pengjian; Du, Chunyu; Yin, Geping

2017-09-01

Orthorhombic Niobium oxide (T-Nb2O5) has been regarded as a promising anode material for high-rate lithium ion batteries (LIBs) due to its potential to operate at high rates with improved safety and high theoretical capacity of 200 mA h g-1. Herein, three-dimensionally ordered macroporous (3DOM) T-Nb2O5, with mesoporous hierarchical structure, was firstly prepared by a simple approach employing self-assembly polystyrene (PS) microspheres as hard templates. The obtained T-Nb2O5 anode material presents obvious and highly-efficiency pseudocapacitive Li+ intercalation behaviour, which plays a dominant role in the kinetics of electrode process. As a result, rapid Li+ intercalation/de-intercalation are achieved, leading to excellent rate capability and long cycle life. The 3DOM T-Nb2O5 shows a remarkable high capacity of 106 and 77 mA h g-1 at the rate of 20C and 50C. The work presented herein holds great promise for future design of material structure, and demonstrates the great potential of T-Nb2O5 as a practical high-rate anode material for LIBs.

Nucleation and growth kinetics for intercalated islands during deposition on layered materials with isolated pointlike surface defects

International Nuclear Information System (INIS)

Han, Yong; Lii-Rosales, A.; Zhou, Y.; Wang, C.-J.

2017-01-01

Theory and stochastic lattice-gas modeling is developed for the formation of intercalated metal islands in the gallery between the top layer and the underlying layer at the surface of layered materials. Our model for this process involves deposition of atoms, some fraction of which then enter the gallery through well-separated pointlike defects in the top layer. Subsequently, these atoms diffuse within the subsurface gallery leading to nucleation and growth of intercalated islands nearby the defect point source. For the case of a single point defect, continuum diffusion equation analysis provides insight into the nucleation kinetics. However, complementary tailored lattice-gas modeling produces a more comprehensive and quantitative characterization. We analyze the large spread in nucleation times and positions relative to the defect for the first nucleated island. We also consider the formation of subsequent islands and the evolution of island growth shapes. The shapes reflect in part our natural adoption of a hexagonal close-packed island structure. As a result, motivation and support for the model is provided by scanning tunneling microscopy observations of the formation of intercalated metal islands in highly-ordered pyrolytic graphite at higher temperatures.

Antitumour Effects of Isocurcumenol Isolated from Curcuma zedoaria Rhizomes on Human and Murine Cancer Cells

Science.gov (United States)

Lakshmi, S.; Padmaja, G.; Remani, P.

2011-01-01

Curcuma zedoaria belonging to the family Zingiberaceae has been used in the traditional system of medicine in India and Southwest Asia in treating many human ailments and is found to possess many biological activities. The rationale of the present study was to isolate, identify, and characterize antitumour principles from the rhizomes of Curcuma zedoaria, to assess its cytotoxic effects on human and murine cancer cells, to determine its apoptosis inducing capacity in cancer cells, and to evaluate its tumour reducing properties in in vivo mice models. Isocurcumenol was characterized as the active compound by spectroscopy and was found to inhibit the proliferation of cancer cells without inducing significant toxicity to the normal cells. Fluorescent staining exhibited the morphological features of apoptosis in the compound-treated cancer cells. In vivo tumour reduction studies revealed that a dose of 35.7 mg/kg body weight significantly reduced the ascitic tumour in DLA-challenged mice and increased the lifespan with respect to untreated control mice. PMID:27429805

Nanostructural drug-inorganic clay composites: Structure, thermal property and in vitro release of captopril-intercalated Mg-Al-layered double hydroxides

International Nuclear Information System (INIS)

Zhang Hui; Zou Kang; Guo Shaohuan; Duan Xue

2006-01-01

A nanostructural drug-inorganic clay composite involving a pharmaceutically active compound captopril (Cpl) intercalated Mg-Al-layered double hydroxides (Cpl-LDHs) with Mg/Al molar ratio of 2.06 has been assembled by coprecipitation method. Powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and Raman spectra analysis indicate a successful intercalation of Cpl between the layers with a vertical orientation of Cpl disulphide-containing S-S linkage. SEM photo indicates that as-synthesized Cpl-LDHs possess compact and non-porous structure with approximately and linked elliptical shape particles of ca. 50 nm. TG-DTA analyses suggest that the thermal stability of intercalated organic species is largely enhanced due to host-guest interaction involving the hydrogen bond compared to pure form before intercalation. The in vitro release studies show that both the release rate and release percentages markedly decrease with increasing pH from 4.60 to 7.45 due to possible change of release mechanism during the release process. The kinetic simulation for the release data, and XRD and FT-IR analyses for samples recovered from release media indicate that the dissolution mechanism is mainly responsible for the release behaviour of Cpl-LDHs at pH 4.60, while the ion-exchange one is responsible for that at pH 7.45. - Graphical abstract: Based on XRD, FT-IR and Raman spectra analyses, it is suggested that captopril (Cpl) exists as its disulphide metabolites in the interlayer of Mg-Al-LDHs via hydrogen bonding between guest carboxylate function and hydroxyl group of the host layers. A schematic supramolecular structure of Cpl intercalates involving a vertical orientation of Cpl disulphide-containing S-S bond between the layers with carboxylate anions pointing to both hydroxide layers is presented

Photoemission study of Ca-intercalated graphite superconductor CaC6

International Nuclear Information System (INIS)

Okazaki, Hiroyuki; Yoshida, Rikiya; Iwai, Keisuke; Noami, Kengo; Muro, Takayuki; Nakamura, Tetsuya; Wakita, Takanori; Muraoka, Yuji; Hirai, Masaaki; Tomioka, Fumiaki; Takano, Yoshihiko; Takenaka, Asami; Toyoda, Masahiro; Oguchi, Tamio; Yokoya, Takayoshi

2010-01-01

In this work, we have performed resonant photoemission studies of Ca-intercalated graphite superconductor CaC 6 . Using photon energy of the Ca 2p-3d threshold, the photoemission intensity of the peak at Fermi energy (E F ) is resonantly enhanced. This result provides spectroscopic evidence for the existence of Ca 3d states at E F , and strongly supports that Ca 3d state plays a crucial role for the superconductivity of this material with relatively high T c .

PEG conjugates in clinical development or use as anticancer agents: an overview.

Science.gov (United States)

Pasut, Gianfranco; Veronese, Francesco M

2009-11-12

During the almost forty years of PEGylation, several antitumour agents, either proteins, peptides or low molecular weight drugs, have been considered for polymer conjugation but only few entered clinical phase studies. The results from the first clinical trials have shared and improved the knowledge on biodistribution, clearance, mechanism of action and stability of a polymer conjugate in vivo. This has helped to design conjugates with improved features. So far, most of the PEG conjugates comprise of a protein, which in the native form has serious shortcomings that limit the full exploitation of its therapeutic action. The main issues can be short in vivo half-life, instability towards degrading enzymes or immunogenicity. PEGylation proved to be effective in shielding sensitive sites at the protein surface, such as antigenic epitopes and enzymatic degradable sequences, as well as in prolonging the drug half-life by decreasing the kidney clearance. In this review PEG conjugates of proteins or low molecular weight drugs, in clinical development or use as anticancer agents, will be taken into consideration. In the case of PEG-protein derivatives the most represented are depleting enzymes, which act by degrading amino acids essential for cancer cells. Interestingly, PEGylated conjugates have been also considered as adjuvant therapy in many standard anticancer protocols, in this regard the case of PEG-G-CSF and PEG-interferons will be presented.

Pemetrexed-carboplatin with intercalated icotinib in the treatment of patient with advanced EGFR wild-type lung adenocarcinoma: A case report.

Science.gov (United States)

Xu, Tongpeng; Wu, Hao; Jin, Shidai; Min, Huang; Zhang, Zhihong; Shu, Yongqian; Wen, Wei; Guo, Renhua

2017-08-01

Tyrosine kinase inhibitors (TKIs) are known to have greater efficacy in epidermal growth factor receptor (EGFR) mutation nonsmall cell lung cancer (NSCLC). However, about 10% of EGFR wild-type (wt) patients respond to TKIs. Several strategies to increase the efficacy of TKIs in wt NSCLC are the subjects of ongoing investigations. One of them is combining EGFR TKI with intercalated chemotherapy. We describe a patient with EGFR wt NSCLC, who was found with ovarian and lung metastasis, was treated with pemetrexed and intercalated icotinib. In this case, we reported the successful long-term maintenance treatment of a patient with EGFR wt NSCLC with pemetrexed and Icotinib. The patient (40-year-old female) was found with ovarian masses and lung masses. Pathological, immunohistochemical, and amplification refractory mutation system (ARMS) assay examinations of ovarian specimen suggested the expression of metastatic lung adenocarcinoma with wt EGFR. After failure treatment with paclitaxel-carboplatin, the patient received 4 cycles of pemetrexed plus platinum with intercalated icotinib and then remained on pemetrexed and icotinib. A partial response was achieved after the treatment. The patient's condition had remained stable on pemetrexed and icotinib for more than 20 months, with no evidence of progression. To our knowledge, this is the first report using the long-term maintenance treatment with pemetrexed and intercalated icotinib in EGFR wt patient. The therapeutic strategies warrant further exploration in selected populations of NSCLC.

Modulating the electronic and magnetic properties of bilayer borophene via transition metal atoms intercalation: from metal to half metal and semiconductor.

Science.gov (United States)

Zhang, Xiuyun; Sun, Yi; Ma, Liang; Zhao, Xinli; Yao, Xiaojing

2018-07-27

Borophene, a two-dimensional monolayer made of boron atoms, has attracted wide attention due to its appealing properties. Great efforts have been devoted to fine tuning its electronic and magnetic properties for desired applications. Herein, we theoretically investigate the versatile electronic and magnetic properties of bilayer borophene (BLB) intercalated by 3d transition metal (TM) atoms, TM@BLBs (TM = Ti-Fe), using ab initio calculations. Four allotropes of AA-stacking (α 1 -, β-, β 12 - and χ 3 -) BLBs with different intercalation concentrations of TM atoms are considered. Our results show that the TM atoms are strongly bonded to the borophene layers with fairly large binding energies, around 6.31 ∼ 15.44 eV per TM atom. The BLBs with Cr and Mn intercalation have robust ferromagnetism, while for the systems decorated with Fe atoms, fruitful magnetic properties, such as nonmagnetic, ferromagnetic or antiferromagnetic, are identified. In particular, the α 1 - and β-BLBs intercalated by Mn or Fe atom can be transformed into a semiconductor, half metal or graphene-like semimetal. Moreover, some heavily doped TM@BLBs expose high Curie temperatures above room temperature. The attractive properties of TM@BLBs entail an efficient way to modulate the electronic and magnetic properties of borophene sheets for advanced applications.

1-, 2-, and 4-Ethynylpyrenes in the Structure of Twisted Intercalating Nucleic Acids: Structure, Thermal Stability, and Fluorescence Relationship

DEFF Research Database (Denmark)

Filichev, Vyacheslav V; Astakhova, Irina V.; Malakhov, Andrei D.

2008-01-01

to ortho in homopyrimidine TINAs. Thus, for para-TINAs the bulge insertion of an intercalator led to high thermal stability of Hoogsteen-type parallel triplexes and duplexes, whereas Watson-Cricktype duplexes were destabilized. In the case of ortho-TINA, both Hoogsteen and Watson-Crick-type complexes were......A postsynthetic, on-column Sonogashira reaction was applied on DNA molecules modified by 2- or 4-iodophenylmethylglycerol in the middle of the sequence, to give the corresponding ortho- and para-twisted intercalating nucleic acids (TINA) with 1-, 2-, and 4-ethynylpyrene residues. The convenient...

Flattening and manipulation of the electronic structure of h-BN/Rh(111) nanomesh upon Sn intercalation

Science.gov (United States)

Sugiyama, Yuya; Bernard, Carlo; Okuyama, Yuma; Ideta, Shin-ichiro; Tanaka, Kiyohisa; Greber, Thomas; Hirahara, Toru

2018-06-01

We have deposited Sn on corrugated hexagonal boron nitride (h-BN) nanomeshs formed on Rh(111) and found that Sn atoms are intercalated between h-BN and Rh, flattening the h-BN. Our reflection high-energy electron diffraction (RHEED) analysis showed that the average in-plane lattice constant of h-BN increases due to the loss of the corrugation. Furthermore, electronic structure measurements based on angle-resolved photoemission spectroscopy (ARPES) showed that the h-BN π band width increases significantly while the σ band width does not change as much. These behaviors were partly different from previous reports on the intercalation of h-BN/Rh system. Our results offer a novel, simple method to control the electronic structure of h-BN.

Intercalated theophylline-smectite hybrid for pH-mediated delivery.

Science.gov (United States)

Trivedi, Vivek; Nandi, Uttom; Maniruzzaman, Mohammed; Coleman, Nichola J

2018-01-23

On the basis of their large specific surface areas, high adsorption and cation exchange capacities, swelling potential and low toxicity, natural smectite clays are attractive substrates for the gastric protection of neutral and cationic drugs. Theophylline is an amphoteric xanthine derivative that is widely used as a bronchodilator in the treatment of asthma and chronic obstructive pulmonary disease. This study considers the in vitro uptake and release characteristics of the binary theophylline-smectite system. The cationic form of theophylline was readily ion exchanged into smectite clay at pH 1.2 with a maximum uptake of 67 ± 2 mg g -1 . Characterisation of the drug-clay hybrid system by powder X-ray diffraction analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy confirmed that the theophylline had been exclusively intercalated into the clay system in an amorphous form. The drug remained bound within the clay under simulated gastric conditions at pH 1.2; and the prolonged release of approximately 40% of the drug was observed in simulated intestinal fluid at pH 6.8 and 7.4 within a 2-h timeframe. The incomplete reversibility of the intercalation process was attributed to chemisorption of the drug within the clay lattice. These findings indicate that smectite clay is a potentially suitable vehicle for the safe passage of theophylline into the duodenum. Protection from absorption in the stomach and subsequent prolonged release in the small intestine are advantageous in reducing fluctuations in serum concentration which may impact therapeutic effect and toxicity.

Synthesis and characterization of laurate-intercalated Mg–Al layered double hydroxide prepared by coprecipitation

DEFF Research Database (Denmark)

Gerds, Nathalie Christiane; Katiyar, Vimal; Koch, Christian Bender

2012-01-01

Effective utilization of layered double hydroxides (LDH) for industrial applications requires the synthesis of pure and well-defined LDH phases. In the present study, dodecanoate (laurate) anions were intercalated into Mg–Al-layered double hydroxide (LDH-C12) by coprecipitation in the presence of...

Intercalates of strontium phenylphosphonate with alcohols - Structure analysis by experimental and molecular modeling methods

Czech Academy of Sciences Publication Activity Database

Zima, Vítězslav; Melánová, Klára; Kovář, P.; Beneš, L.; Svoboda, Jan; Pospíšil, M.; Růžička, A.

2015-01-01

Roč. 2015, č. 9 (2015), s. 1552-1561 ISSN 1434-1948 R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : layered compounds * intercalation * molecular modeling Subject RIV: CA - Inorganic Chemistry Impact factor: 2.686, year: 2015

Increased risk of post-operative complications in patients with Crohn's disease treated with anti-tumour necrosis factor α agents - a systematic review

DEFF Research Database (Denmark)

El-Hussuna, Alaa; Theede, Klaus; Olaison, Gunnar

2014-01-01

INTRODUCTION: Tumour necrosis factor α (TNF-α) plays a role in the immune defence, angiogenesis and collagen synthesis. Inhibition of these pathways may increase the risk of infections and impair wound healing in patients after surgery. Biologic treatments including anti-TNF-α agents are increasi......INTRODUCTION: Tumour necrosis factor α (TNF-α) plays a role in the immune defence, angiogenesis and collagen synthesis. Inhibition of these pathways may increase the risk of infections and impair wound healing in patients after surgery. Biologic treatments including anti-TNF-α agents...... are increasingly used in the treatment of inflammatory bowel disease. Taking into consideration the biologics' mechanism of action, fears have been expressed that they might increase the rate of post-operative complications. Results from 18 retrospective studies were conflicting, and meta-analyses based...... an increased risk of overall post-operative complications and an increased rate of infectious or anastomosis-related complications in patients receiving anti-TNF-α. CONCLUSION: The use of anti-TNF-α agents in Crohn's disease patients is associated with an increased risk of post-operative complications after...

Topotactic synthesis of the overlooked multilayer silicene intercalation compound SrSi2.

Science.gov (United States)

Tokmachev, A M; Averyanov, D V; Karateev, I A; Parfenov, O E; Vasiliev, A L; Yakunin, S N; Storchak, V G

2016-09-28

Silicene, a 2D honeycomb lattice of Si atoms similar to graphene, is expected to be a platform for nanoelectronics and home to novel quantum phenomena. Unlike graphene, free-standing silicene is notoriously difficult to stabilize, while strong hybridization of silicene with substrates destroys its desirable properties. On the other hand, Dirac cones of silicene are effectively realized in a bulk - stoichiometric ionic multilayer silicene intercalation compound CaSi2. Besides, a number of new 2D silicene-based materials are synthesized employing CaSi2 as a precursor. However, the rather complex atomic structure of CaSi2 and fresh opportunities of physical and chemical breakthroughs drive the search for alternative compounds with silicene networks. Here, a new polymorph of SrSi2 is synthesized, enjoying both the structure of intercalated multilayer silicene and the simplest possible stacking of silicene sheets. The MBE-quality synthesis accomplished on Si(001) and Si(111) surfaces leads to epitaxial films of SrSi2 with orientation controlled by the substrate, as revealed by XRD, RHEED and electron microscopy studies. The structural SrSi2/Si relation is mirrored in the transport properties of the films.

Metal porphyrin intercalated reduced graphene oxide nanocomposite utilized for electrocatalytic oxygen reduction

Directory of Open Access Journals (Sweden)

Mingyan Wang

2017-07-01

Full Text Available In this paper, we report a simple and facile self-assembly method to successfully fabricate cationic metal porphyrin –MtTMPyP (Mt= Cobalt (II, Manganese (III, or Iron (III; TMPyP = 5, 10, 15, 20-tetrakis (N-methylpyridinium-4-yl porphyrin intercalated into the layer of graphene oxide (GO by the cooperative effects of electrostatic and π–π stacking interaction between positively charged metal porphyrin and negatively charged GO sheets. Followed by reduction with hydrazine vapor, a series of novel 2D MtTMPyP/rGOn were fabricated. The as-prepared 2D hybrids were fully characterized and tested as non-noble metal catalysts for oxygen reduction reaction (ORR in an alkaline medium. The MtTMPyP/rGOn hybrids, especially CoTMPyP/rGO5, demonstrated an improved electrocatalytic activity for ORR and a number of exchanged electrons close to 4-electron reaction, increased stability and excellent tolerance to methanol, showing a potential alternative catalyst for ORR in fuel cells and air batteries. Keywords: Metal porphyrin, Reduced graphene oxide, Intercalation, Oxygen reduction reaction, Catalyst

Dielectric properties of halloysite and halloysite-formamide intercalate

Energy Technology Data Exchange (ETDEWEB)

Adamczyk, M., E-mail: mariusz.adamczyk@chem.uni.wroc.pl; Rok, M.; Wolny, A.; Orzechowski, K. [Faculty of Chemistry, University of Wroclaw, Wroclaw 50-383 (Poland)

2014-01-14

Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications.

Dielectric properties of halloysite and halloysite-formamide intercalate

International Nuclear Information System (INIS)

Adamczyk, M.; Rok, M.; Wolny, A.; Orzechowski, K.

2014-01-01

Due to a high increase in electromagnetic pollution, the protection from non-ionizing electromagnetic radiation (EMR) represents an important problem of contemporary environmental science. We are searching for natural materials with the potential for EMR screening. We have discovered that hydro-halloysite has interesting properties as an EMR absorber. Unfortunately, it is a very unstable material. Drying it for even a short period of time leads to the loss of desired properties. In the paper, we have demonstrated that the intercalation of halloysite (the process of introducing guest molecules into the mineral structure) makes it possible to recover the ability to absorb an electromagnetic wave and obtain a promising material for electromagnetic field shielding applications

Renal type a intercalated cells contain albumin in organelles with aldosterone-regulated abundance.

Directory of Open Access Journals (Sweden)

Thomas Buus Jensen

Full Text Available Albumin has been identified in preparations of renal distal tubules and collecting ducts by mass spectrometry. This study aimed to establish whether albumin was a contaminant in those studies or actually present in the tubular cells, and if so, identify the albumin containing cells and commence exploration of the origin of the intracellular albumin. In addition to the expected proximal tubular albumin immunoreactivity, albumin was localized to mouse renal type-A intercalated cells and cells in the interstitium by three anti-albumin antibodies. Albumin did not colocalize with markers for early endosomes (EEA1, late endosomes/lysosomes (cathepsin D or recycling endosomes (Rab11. Immuno-gold electron microscopy confirmed the presence of albumin-containing large spherical membrane associated bodies in the basal parts of intercalated cells. Message for albumin was detected in mouse renal cortex as well as in a wide variety of other tissues by RT-PCR, but was absent from isolated connecting tubules and cortical collecting ducts. Wild type I MDCK cells showed robust uptake of fluorescein-albumin from the basolateral side but not from the apical side when grown on permeable support. Only a subset of cells with low peanut agglutinin binding took up albumin. Albumin-aldosterone conjugates were also internalized from the basolateral side by MDCK cells. Aldosterone administration for 24 and 48 hours decreased albumin abundance in connecting tubules and cortical collecting ducts from mouse kidneys. We suggest that albumin is produced within the renal interstitium and taken up from the basolateral side by type-A intercalated cells by clathrin and dynamin independent pathways and speculate that the protein might act as a carrier of less water-soluble substances across the renal interstitium from the capillaries to the tubular cells.

Interlayer Structures and Dynamics of Arsenate and Arsenite Intercalated Layered Double Hydroxides: A First Principles Study

Directory of Open Access Journals (Sweden)

Yingchun Zhang

2017-03-01

Full Text Available In this study, by using first principles simulation techniques, we explored the basal spacings, interlayer structures, and dynamics of arsenite and arsenate intercalated Layered double hydroxides (LDHs. Our results confirm that the basal spacings of NO3−-LDHs increase with layer charge densities. It is found that Arsenic (As species can enter the gallery spaces of LDHs with a Mg/Al ratio of 2:1 but they cannot enter those with lower charge densities. Interlayer species show layering distributions. All anions form a single layer distribution while water molecules form a single layer distribution at low layer charge density and a double layer distribution at high layer charge densities. H2AsO4− has two orientations in the interlayer regions (i.e., one with its three folds axis normal to the layer sheets and another with its two folds axis normal to the layer sheets, and only the latter is observed for HAsO42−. H2AsO3− orientates in a tilt-lying way. The mobility of water and NO3− increases with the layer charge densities while As species have very low mobility. Our simulations provide microscopic information of As intercalated LDHs, which can be used for further understanding of the structures of oxy-anion intercalated LDHs.

Basic dye removal from aqueous solutions by dodecylsulfate- and dodecyl benzene sulfonate-intercalated hydrotalcite

Energy Technology Data Exchange (ETDEWEB)

Bouraada, Mohamed; Lafjah, Mama [Laboratoire de valorisation des materiaux, University of Mostaganem, B.P. 227, Mostaganem R.P. (Algeria); Ouali, Mohand Said [Laboratoire de valorisation des materiaux, University of Mostaganem, B.P. 227, Mostaganem R.P. (Algeria)], E-mail: ouali@univ-mosta.dz; Menorval, Louis Charles de [LAMMI (CNRS-UMR5072), Universite Montpellier II, 2 Place Eugene Bataillon, Case Courrier 015, 34095 Montpellier cedex 5 (France)

2008-05-30

Dodecylsulfate- and dodecyl benzene sulfonate-hydrotalcites were prepared by calcination-rehydratation method. The surfactants intercalation in the interlayer space of hydrotalcite were checked by PXRD and FTIR spectroscopy where the resulting materials were found to be similar to those reported in the literature and were used to remove a basic dye (safranine) from aqueous solutions. The sorption kinetics data fitted the pseudo second order model. The isotherms were established and the parameters calculated. The sorption data fitted the Langmuir model with good values of the determination coefficient. The thermodynamic parameters calculated from Van't Hoff plots gave a low value of {delta}G{sup o} (<-20 kJ mol{sup -1}) indicating a spontaneous physisorption process. Two regeneration cycles were processed by acetone extraction leading to the same removal capacity of the obtained materials as the original surfactant-intercalated hydrotalcites. The UV-vis spectra of the recovered extracts were similar to the spectrum of safranine, which means that the dye was recovered without any modification.

A DNA biosensor based on the electrocatalytic oxidation of amine by a threading intercalator

International Nuclear Information System (INIS)

Gao Zhiqiang; Tansil, Natalia

2009-01-01

An electrochemical biosensor for the detection of DNA based a peptide nucleic acid (PNA) capture probe (CP) modified indium tin oxide electrode (ITO) is described in this report. After hybridization, a threading intercalator, N,N'-bis[(3-propyl)-imidazole]-1,4,5,8-naphthalene diimide (PIND) imidazole complexed with Ru(bpy) 2 Cl (PIND-Ru, bpy = 2,2'-bipyridine), was introduced to the biosensor. PIND-Ru selectively intercalated to double-stranded DNA (ds-DNA) and became immobilized on the biosensor surface. Voltammetric tests showed highly stable and reversible electrochemical oxidation/reduction processes and the peak currents can directly be utilized for DNA quantification. When the tests were conducted in an amine-containing medium, Tris-HCl buffer for example, a remarkable improvement in the voltammetric response and noticeable enhancements of voltammetric and amperometric sensitivities were observed due to the electrocatalytic activity of the [Ru(bpy) 2 Cl] redox moieties. Electrocatalytic current was observed when as little as 3.0 attomoles of DNA was present in the sample solution

Intercalation compounds involving inorganic layered structures

Directory of Open Access Journals (Sweden)

CONSTANTINO VERA R. L.

2000-01-01

Full Text Available Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts.

SUPPRESSION OF HUMORAL IMMUNE RESPONSES BY 2,3,7,8-TETRACHLORODIBENZO-p-DIOXIN INTERCALATED IN SMECTITE CLAY

Science.gov (United States)

Boyd, Stephen A.; Johnston, Cliff T.; Pinnavaia, Thomas J.; Kaminski, Norbert E.; Teppen, Brian J.; Li, Hui; Khan, Bushra; Crawford, Robert B.; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L.F.

2018-01-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. PMID:21994089

Intercalated vs Nonintercalated Morphologies in Donor-Acceptor Bulk Heterojunction Solar Cells: PBTTT:Fullerene Charge Generation and Recombination Revisited.

Science.gov (United States)

Collado-Fregoso, Elisa; Hood, Samantha N; Shoaee, Safa; Schroeder, Bob C; McCulloch, Iain; Kassal, Ivan; Neher, Dieter; Durrant, James R

2017-09-07

In this Letter, we study the role of the donor:acceptor interface nanostructure upon charge separation and recombination in organic photovoltaic devices and blend films, using mixtures of PBTTT and two different fullerene derivatives (PC 70 BM and ICTA) as models for intercalated and nonintercalated morphologies, respectively. Thermodynamic simulations show that while the completely intercalated system exhibits a large free-energy barrier for charge separation, this barrier is significantly lower in the nonintercalated system and almost vanishes when energetic disorder is included in the model. Despite these differences, both femtosecond-resolved transient absorption spectroscopy (TAS) and time-delayed collection field (TDCF) exhibit extensive first-order losses in both systems, suggesting that geminate pairs are the primary product of photoexcitation. In contrast, the system that comprises a combination of fully intercalated polymer:fullerene areas and fullerene-aggregated domains (1:4 PBTTT:PC 70 BM) is the only one that shows slow, second-order recombination of free charges, resulting in devices with an overall higher short-circuit current and fill factor. This study therefore provides a novel consideration of the role of the interfacial nanostructure and the nature of bound charges and their impact upon charge generation and recombination.

Properties of K,Rb-intercalated C60 encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

KAUST Repository

Mahfouz, Remi

2015-09-18

We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C60 encapsulated inside carbon nanotubes called peapods can be derived from 13C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T1) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C60 that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C60 at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(EF).

Monoclonal antibodies for radioimmunodetection of tumours and for targeting

International Nuclear Information System (INIS)

Baldwin, R.W.; Embleton, M.J.; Pimm, M.V.

1983-01-01

A monoclonal antibody 791T/36 prepared against human osteogenic sarcoma has been used to detect primary and metastatic colorectal carcinomas by external imaging of patients following injection of 131 I-labelled antibody. In 10 of 11 patients radiolabelled 791T/36 antibody localized in tumours, the tumour/non tumour ratio of radioactivity ranging from 1.5:1 to 8.1. 791T/36 antibody was also evaluated for its potential for targeting anti-tumour agents including cytotoxic drugs (Vindesine) and immunomodulating agents (interferon). Vindesine-791T/36 conjugates were preferentially cytotoxic in vitro for target cells expressing the 791T/36 anti-body defined antigen. Also interferon conjugated to 791T/36 antibody, like free interferon activated peripheral blood natural killer cell activity. These in vitro tests together with related studies on antibody localization in vivo indicate the potential of monoclonal antibody targeting of anti-tumour agents

Controlling Water Intercalation Is Key to a Direct Graphene Transfer.

Science.gov (United States)

Verguts, Ken; Schouteden, Koen; Wu, Cheng-Han; Peters, Lisanne; Vrancken, Nandi; Wu, Xiangyu; Li, Zhe; Erkens, Maksiem; Porret, Clement; Huyghebaert, Cedric; Van Haesendonck, Chris; De Gendt, Stefan; Brems, Steven

2017-10-25

The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments, these steps remain very challenging, and transfer variations often result in unreliable 2D material properties. Here, it is demonstrated that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene. It is understood that interfacial water is essential for an electrochemistry-based graphene delamination from a Pt surface. Additionally, the lamination of graphene to a target wafer is hindered by intercalation effects, which can even result in graphene delamination from the target wafer. For circumvention of these issues, a direct, support-free graphene transfer process is demonstrated, which relies on the formation of interfacial water between graphene and its growth surface, while avoiding water intercalation between graphene and the target wafer by using hydrophobic silane layers on the target wafer. The proposed direct graphene transfer also avoids polymer contamination (no temporary support layer) and eliminates the need for etching of the catalyst metal. Therefore, recycling of the growth template becomes feasible. The proposed transfer process might even open the door for the suggested atomic-scale interlocking-toy-brick-based stacking of different 2D materials, which will enable a more reliable fabrication of van der Waals heterostructure-based devices and applications.

Carboxylate-intercalated layered double hydroxides aged under microwave-hydrothermal treatment

International Nuclear Information System (INIS)

Benito, P.; Labajos, F.M.; Mafra, L.; Rocha, J.; Rives, V.

2009-01-01

Carboxylate-intercalated (terephthalate, TA and oxalate, ox) layered double hydroxides (LDHs) are aged under a microwave-hydrothermal treatment. The influence of the nature of the interlayer anion during the ageing process is studied. Characterization results show that the microwave-hydrothermal method can be extended to synthesize LDHs with anions different than carbonate, like TA. LDH-TA compounds are stable under microwave irradiation for increasing periods of time and the solids show an improved order both in the layers and in the interlayer region as evidenced by powder X-ray diffraction (PXRD), 27 Al MAS NMR and FT-IR spectroscopy. Furthermore, cleaning of the surface through removal of some organic species adsorbed on the surface of the particles also occurs during the microwave-hydrothermal treatment. Conversely, although the expected increase in crystallinity is observed in LDH-ox samples, the side-reaction between Al 3+ and ox is also enhanced under microwave irradiation, and a partial destruction of the structure takes place with an increase in the M 2+ /M 3+ ratio and consequent modification of the cell parameters. - Graphical Abstract: The influence of the nature of the interlayer anion during the ageing process of carboxylate-intercalated (TA and ox) hydrotalcite-like compounds (HTlcs) is studied. Well crystallized for TA-containing compounds were obtained. However, the non-desired side-reaction of ox with the aluminum of the layers is enhanced by the microwaves and a partial destruction of the structure takes place

Sythesis of rare earth metal - GIC graphite intercalation compound in molten chloride system

International Nuclear Information System (INIS)

Ito, Masafumi; Hagiwara, Rika; Ito, Yasuhiko

1994-01-01

Graphite intercalation compounds of ytterbium and neodymium have been prepared by interacting graphite and metals in molten chlorides. These rare earth metals can be suspended in molten chlorides in the presence of trichlorides via disproportionation reaction RE(0) + RE(III) = 2RE(II) at lower than 300 degC. Carbides-free compounds are obtained in these systems. (author)

In Vitro Inhibition of Histamine Release Behavior of Cetirizine Intercalated into Zn/Al- and Mg/Al-Layered Double Hydroxides

Directory of Open Access Journals (Sweden)

Muhammad Nazrul Hakim

2012-05-01

Full Text Available The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively.

Absence of photoemission from the Fermi level in potassium intercalated picene and coronene films: structure, polaron, or correlation physics?

Science.gov (United States)

Mahns, Benjamin; Roth, Friedrich; Knupfer, Martin

2012-04-07

The electronic structure of potassium intercalated picene and coronene films has been studied using photoemission spectroscopy. Picene has additionally been intercalated using sodium. Upon alkali metal addition core level as well as valence band photoemission data signal a filling of previously unoccupied states of the two molecular materials due to charge transfer from potassium. In contrast to the observation of superconductivity in K(x)picene and K(x)coronene (x ~ 3), none of the films studied shows emission from the Fermi level, i.e., we find no indication for a metallic ground state. Several reasons for this observation are discussed.

Improvements on the synthesis and properties of fluorinated polyimide-clay nanocomposites by using double-swelling agents

International Nuclear Information System (INIS)

Wang, H.-W.; Dong, R.-X.; Chu, H.-C.; Chang, K.-C.; Lee, W.-C.

2005-01-01

Polyimide (6FBpA-6FDA)-montmorillonite nanocomposites (PiCN) were synthesized from modified montmorillonite (MMT) and poly(amic acid), using single- and double-swelling agents. The silicate layers of clay in the matrix of 6FBpA-6FDA were intercalated and became more exfoliated when double (DAETPB-ODA) swelling agents were used to modify the montmorillonite. Structures of exfoliation were confirmed by wide-angle X-ray diffraction (WAXRD) and transmission electron microscopy (TEM). The improved exfoliation of nanocomposites by the double-swelling agents resulted in enhanced thermal and mechanical properties. In particular, the maximum increase in T d , T g , and storage modulus of these nanocomposites was found to be those with addition of 5.0 wt% DAETPB-ODA modified-MMT. The moisture absorption of these nanocomposites was also reduced by the addition of double-swelling agent-modified MMT. The dielectric properties of PiCN in the form of film with MMT loading from 1.0 to 5.0 wt% were measured under frequencies of 100 Hz-1 MHz at 35-150 deg. C. Reduced dielectric constants were observed for these fluorinated polyimide-clay nanocomposites

Preparation of C.I. Pigment 52:1 anion-pillared layered double hydroxide and the thermo- and photostability of the resulting intercalated material

Science.gov (United States)

Guo, Shengchang; Evans, David G.; Li, Dianqing

2006-05-01

Intercalation of 2-naphthalenecarboxylic acid, 4-((4-chloro-5-methyl-2-sulfophenyl) azo)-3-hydroxy-, calcium salt (1:1) (C.I. Pigment Red 52:1, also known as New Rubine S6B) into a layered double hydroxide (LDHs) host was carried out using MgAl NO3 LDHs as a precursor in an effort to improve the thermal and photo stability of the pigment. After intercalation, the powder X-ray diffraction (XRD) pattern shows that the basal spacing of the LDHs increased from 0.86 to 1.92 nm. Infrared spectra and TG DTA curves demonstrate that there are supramolecular host guest interactions. It was found that the intercalated material is more stable than the pristine pigment at high temperatures. The pigment anion-pillared LDHs also exhibit much higher photostablity to UV-light than the pristine pigment.

Id1 suppresses anti-tumour immune responses and promotes tumour progression by impairing myeloid cell maturation.

Science.gov (United States)

Papaspyridonos, Marianna; Matei, Irina; Huang, Yujie; do Rosario Andre, Maria; Brazier-Mitouart, Helene; Waite, Janelle C; Chan, April S; Kalter, Julie; Ramos, Ilyssa; Wu, Qi; Williams, Caitlin; Wolchok, Jedd D; Chapman, Paul B; Peinado, Hector; Anandasabapathy, Niroshana; Ocean, Allyson J; Kaplan, Rosandra N; Greenfield, Jeffrey P; Bromberg, Jacqueline; Skokos, Dimitris; Lyden, David

2015-04-29

A central mechanism of tumour progression and metastasis involves the generation of an immunosuppressive 'macroenvironment' mediated in part through tumour-secreted factors. Here we demonstrate that upregulation of the Inhibitor of Differentiation 1 (Id1), in response to tumour-derived factors, such as TGFβ, is responsible for the switch from dendritic cell (DC) differentiation to myeloid-derived suppressor cell expansion during tumour progression. Genetic inactivation of Id1 largely corrects the myeloid imbalance, whereas Id1 overexpression in the absence of tumour-derived factors re-creates it. Id1 overexpression leads to systemic immunosuppression by downregulation of key molecules involved in DC differentiation and suppression of CD8 T-cell proliferation, thus promoting primary tumour growth and metastatic progression. Furthermore, advanced melanoma patients have increased plasma TGFβ levels and express higher levels of ID1 in myeloid peripheral blood cells. This study reveals a critical role for Id1 in suppressing the anti-tumour immune response during tumour progression and metastasis.

Influence of water contamination and conductive additives on the intercalation of lithium into graphite

Energy Technology Data Exchange (ETDEWEB)

Joho, F; Rykart, B; Novak, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Spahr, M E; Monnier, A [Timcal AG, Sins (Switzerland)

1999-08-01

The irreversible charge loss in the first cycle of lithium intercalation into graphite electrodes for lithium-ion batteries is discussed as a function of water contamination of the electrolyte solution. Furthermore, the improvement of the electrode cycle life due to conductive additives to graphite is demonstrated. (author) 5 figs., 3 refs.

Conjugation of a 3-(1H-phenanthro[9,10-d]imidazol-2-yl)-1H-indole intercalator to a triplex oligonucleotide and to a three-way junction

DEFF Research Database (Denmark)

Fatthalla, Maha I.; Elkholy, Yehya M; Abbas, Nermeen S

2012-01-01

a phenanthroimidazole moiety linked to the indole ring. Insertion of the new intercalator as a bulge into a Triplex Forming Oligonucleotide resulted in good thermal stability of the corresponding Hoogsteen-type triplexes. Molecular modeling supports the possible intercalating ability of M. Hybridisation properties...

Synthesis, characterization, and controlled release anticorrosion behavior of benzoate intercalated Zn-Al layered double hydroxides

Energy Technology Data Exchange (ETDEWEB)

Wang, Yi [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Zhang, Dun, E-mail: zhangdun@qdio.ac.cn [Shandong Provincial Key Lab of Corrosion Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)

2011-11-15

Graphical abstract: The benzoate anion released from Zn-Al LDHs provides a more effective long-term protection against corrosion of Q235 carbon steel in 3.5% NaCl solution. Highlights: {yields} A benzoate anion corrosion inhibitor intercalated Zn-Al layered double hydroxides (LDHs) has been assembled by coprecipitation method. {yields} The kinetic simulation indicates that the ion-exchange one is responsible for the release process and the diffusion through particle is the rate limiting step. {yields} A significant reduction of the corrosion rate is observed when the LDH nanohybrid is present in the corrosive media. -- Abstract: Corrosion inhibitor-inorganic clay composite including benzoate anion intercalated Zn-Al layered double hydroxides (LDHs) are assembled by coprecipitation. Powder X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectrum analyses indicate that the benzoate anion is successfully intercalated into the LDH interlayer and the benzene planes are vertically bilayer-positioned as a quasi-guest ion-pair form in the gallery space. Kinetic simulation for the release data, XRD and FT-IR analyses of samples recovered from the release medium indicate that ion-exchange is responsible for the release process and diffusion through the particle is also indicated to be the rate-limiting step. The anticorrosion capabilities of LDHs loaded with corrosion inhibitor toward Q235 carbon steel are analyzed by polarization curve and electrochemical impedance spectroscopy methods. Significant reduction of corrosion rate is observed when the LDH nanohybrid is present in the corrosive medium. This hybrid material may potentially be applied as a nanocontainer in self-healing coatings.

Clay intercalation and influence on crystallinity of EVA-based clay nanocomposites

International Nuclear Information System (INIS)

Chaudhary, D.S.; Prasad, R.; Gupta, R.K.; Bhattacharya, S.N.

2005-01-01

Various polymer clay nanocomposites (PCNs) were prepared from ethylene vinyl acetate copolymer (EVA) with 9, 18 and 28% vinyl acetate (VA) content filled with different wt.% (2.5, 5 and 7.5) of a Montmorillonite-based organo-modified clay (Cloisite[reg] C15A and C30B). The PCNs were prepared using melt blending techniques. Morphological information regarding intercalation and exfoliation were determined by using wide-angle X-ray scattering (WAXS) and transmission electron microscopy (TEM). WAXS and TEM confirmed that increasing the VA content was necessary to achieve greater clay-polymer interaction as seen from the comparatively higher intercalation of clay platelets with 28% VA. The effect of addition of clay on the development and the modification of crystalline morphology in EVA matrix was also studied using WAXS and temperature-modulated differential scanning calorimetry (MDSC). Results are presented showing that the addition of clay platelets does not increase the matrix crystallinity but the morphology was significantly modified such that there was an increase in the 'rigid' amorphous phase. Mechanical properties were also evaluated against the respective morphological information for each specimen and there are indications that the level of clay-polymer interaction plays a significant role in such morphological modification, and in such a way that affects the final PCN mechanical properties which has wide and significant applications in the packaging industries

Thermal decomposition of cesium-ethylene-ternary graphite intercalation compounds

International Nuclear Information System (INIS)

Matsumoto, R.; Oishi, Y.; Arii, T.

2010-01-01

In this paper, the thermal decomposition of air-stable Cs-ethylene-ternary graphite intercalation compounds (GICs) is discussed. The air stability of Cs-GICs is improved remarkably after the absorption of ethylene into their interlayer nanospace, because the ethylene molecules oligomerize and block the movement of Cs atoms. In addition, the evaporation of Cs atoms from the Cs-ethylene-ternary GICs is observed above 400 o C under a N 2 atmosphere of 100 Pa by ion attachment mass spectrometry. Although the results indicate that Cs-ethylene-ternary GICs remain stable up to approximately 400 o C, their thermal stability is not very high as compared to that of Cs-GICs.

Design of copper DNA intercalators with leishmanicidal activity.

Science.gov (United States)

Navarro, Maribel; Cisneros-Fajardo, Efrén José; Sierralta, Aníbal; Fernández-Mestre, Mercedes; Silva, Pedro; Arrieche, Dwight; Marchán, Edgar

2003-04-01

The complexes [Cu(dppz)(NO(3))]NO(3) (1), [Cu(dppz)(2)(NO(3))]NO(3) (2), [Cu(dpq)(NO(3))]NO(3) (3), and [Cu(dpq)(2)(NO(3))]NO(3) (4) were synthesized and characterized by elemental analysis, FAB-mass spectrometry, EPR, UV, and IR spectroscopies, and molar conductivity. DNA interaction studies showed that intercalation is an important way of interacting with DNA for these complexes. The biological activity of these copper complexes was evaluated on Leishmania braziliensis promastigotes, and the results showed leishmanicidal activity. Preliminary ultrastructural studies with the most active complex (2) at 1 h revealed parasite swelling and binucleated cells. This finding suggests that the leishmanicidal activity of the copper complexes could be associated with their interaction with the parasitic DNA.

STUDYING THE INFLUENCE OF THE PYRENE INTERCALATOR TINA ON THE STABILITY OF DNA i-MOTIFS

DEFF Research Database (Denmark)

El-Sayed, Ahmed A.; Pedersen, Erik Bjerregaard; Khaireldin, Nahid A.

2012-01-01

Certain cytosine-rich (C-rich) DNA sequences can fold into secondary structures as four-stranded i-motifs with hemiprotonated base pairs. Here we synthesized C-rich TINA-intercalating oligonucleotides by inserting a nonnucleotide pyrene moiety between two C-rich regions. The stability of their i-...

Suppression of humoral immune responses by 2,3,7,8-tetrachlorodibenzo-p-dioxin intercalated in smectite clay.

Science.gov (United States)

Boyd, Stephen A; Johnston, Cliff T; Pinnavaia, Thomas J; Kaminski, Norbert E; Teppen, Brian J; Li, Hui; Khan, Bushra; Crawford, Robert B; Kovalova, Natalia; Kim, Seong-Su; Shao, Hua; Gu, Cheng; Kaplan, Barbara L F

2011-12-01

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic environmental contaminant found in soils and sediments. Because of its exceptionally low water solubility, this compound exists predominantly in the sorbed state in natural environments. Clay minerals, especially expandable smectite clays, are one of the major component geosorbents in soils and sediments that can function as an effective adsorbent for environmental dioxins, including TCDD. In this study, TCDD was intercalated in the smectite clay saponite by an incipient wetness method. The primary goal of this study was to intercalate TCDD in natural K-saponite clay and evaluate its immunotoxic effects in vivo. The relative bioavailability of TCDD was evaluated by comparing the metabolic activity of TCDD administered in the adsorbed state as an intercalate in saponite and freely dissolved in corn oil. This comparison revealed nearly identical TCDD-induced suppression of humoral immunity, a well-established and sensitive sequela, in a mammalian (mouse) model. This result suggests that TCDD adsorbed by clays is likely to be available for biouptake and biodistribution in mammals, consistent with previous observations of TCDD in livestock exposed to dioxin-contaminated ball clays that were used as feed additives. Adsorption of TCDD by clay minerals does not appear to mitigate risk associated with TCDD exposure substantially. Copyright © 2011 SETAC.

The effect of surface-bulk potential difference on the kinetics of intercalation in core-shell active cathode particles

Science.gov (United States)

Kazemiabnavi, Saeed; Malik, Rahul; Orvananos, Bernardo; Abdellahi, Aziz; Ceder, Gerbrand; Thornton, Katsuyo

2018-04-01

Surface modification of active cathode particles is commonly observed in battery research as either a surface phase evolving during the cycling process, or intentionally engineered to improve capacity retention, rate capability, and/or thermal stability of the cathode material. Here, a continuum-scale model is developed to simulate the galvanostatic charge/discharge of a cathode particle with core-shell heterostructure. The particle is assumed to be comprised of a core material encapsulated by a thin layer of a second phase that has a different open-circuit voltage. The effect of the potential difference between the surface and bulk phases (Ω) on the kinetics of lithium intercalation and the galvanostatic charge/discharge profiles is studied at different values of Ω, C-rates, and exchange current densities. The difference between the Li chemical potential in the surface and bulk phases of the cathode particle results in a concentration difference between these two phases. This leads to a charge/discharge asymmetry in the galvanostatic voltage profiles, causing a decrease in the accessible capacity of the particle. These effects are more significant at higher magnitudes of surface-bulk potential difference. The proposed model provides detailed insight into the kinetics and voltage behavior of the intercalation/de-intercalation processes in core-shell heterostructure cathode particles.

Layered hydroxides intercalated with organic anions and their application in preparation of LDH/polymer nanocomposites

Czech Academy of Sciences Publication Activity Database

Kovanda, F.; Jindová, E.; Doušová, B.; Koloušek, D.; Pleštil, Josef; Sedláková, Zdeňka

2009-01-01

Roč. 6, č. 1 (2009), s. 111-119 ISSN 1214-9705 R&D Projects: GA AV ČR KAN100500651 Institutional research plan: CEZ:AV0Z40500505 Keywords : hydrotalcite * layered double hydroxides * intercalation Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.275, year: 2009

Synthesis and structural characterization of coaxial nano tubes intercalated of molybdenum disulfide with carbon

International Nuclear Information System (INIS)

Reza San German, C.M.

2005-01-01

In this work the study of some fundamental aspects in the growth of unidimensional systems of coaxial nano tubes from the mold method is approached. This method is an inclusion technique of a precursor reagent into oxide nano porous alumina film (mold), and later applying some processes of synthesis it is gotten to obtain the wished material. The synthesized structures are identified later because they take place by means of the initial formation of nano tubes of MoS 2 , enclosing to carbon nano tubes by the same method, with propylene flow which generates a graphitization process that 'copy' the mold through as it flows. Binary phase MoS 2 + C nano tubes were synthesized by propylene pyrolysis inside MoS 2 nano tubes prepared by template assisted technique. The large coaxial nano tubes constituted of graphite sheets inserted between the MoS 2 layers forming the outer part, and coaxial multi wall carbon nano tubes (MWCNT) intercalated with MoS 2 inside. High resolution electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), high angle annular dark field (HAADF), gatan image filter (GIF), nano beam electron diffraction patterns (NBEDP), along with molecular dynamics simulation and quantum mechanical calculations were used to characterize the samples. The one-dimensional structures exhibit diverse morphologies such as long straight and twisted nano tubes with several structural irregularities. The inter-planar spacing between MoS 2 layers was found to increase from 6.3 to 7.4 A due to intercalation with carbon. Simulated HREM images revealed the presence of these twisted nano structures, with mechanical stretch into intercalate carbon between MoS 2 layers. Our results open up the possibility of using MoS 2 nano tubes as templates for the synthesis of new one- dimensional binary phase systems. (Author)

The influence of hydrogen intercalation on inner pressure of Ni/MH battery during fast charge

Science.gov (United States)

Shi, Jianzhen; Wu, Feng; Hu, Daozhong; Chen, Shi; Mao, Licai; Wang, Guoqing

Gaseous hydrogen is confirmed to be the main component and primarily responsible for the inner pressure rise inside the 8-Ah Ni/MH batteries during fast charge. Based on a temperature-dependent pressure model proposed in this work, the kinetic characteristics of the hydrogen evolution were investigated. The overpotential and exchange current density were obtained by fitting the presented equation to the experimental data. Moreover, the profiles of hydrogen concentration during fast charge was further modeled and calculated according to the proposed mathematical model of hydrogen intercalation. It is indicated that diffusion step controls the fast charge performances and the higher the charge rate is, the more quickly the negative electrode attains to the maximum surface intercalation fraction, and however, the calculated results also show that further charge can reduce the difference of charge efficiency among the various rate during fast charge. Numerical investigations also reveal that the increase of diffusion coefficient and decrease of the particle size can efficiently improve the characteristics of fast charge, respectively.

10th International School of Materials Science and Technology : Intercalation in Layered Materials "Ettore Majorana"

CERN Document Server

1986-01-01

This volume is prepared from lecture notes for the course "Intercalation in Layered Materials" which was held at the Ettore Majorana Centre for Scientific Culture at Erice, Sicily in July, 1986, as part of the International School of Materials Science and Tech­ nology. The course itself consisted of formal tutorial lectures, workshops, and informal discussions. Lecture notes were prepared for the formal lectures, and short summaries of many of the workshop presentations were prepared. This volume is based on these lecture notes and research summaries. The material is addressed to advanced graduate students and postdoctoral researchers and assumes a background in basic solid state physics. The goals of this volume on Intercalation in Layered Materials include an introduc­ tion to the field for potential new participants, an in-depth and broad exposure for stu­ dents and young investigators already working in the field, a basis for cross-fertilization between workers on various layered host materials...

Synthesis of SnSe nanosheets by hydrothermal intercalation and exfoliation route and their photoresponse properties

Energy Technology Data Exchange (ETDEWEB)

Ren, Xiaohui; Qi, Xiang, E-mail: xqi@xtu.edu.cn; Shen, Yongzhen; Xu, Guanghua; Li, Jun; Li, Zhenqing; Huang, Zongyu; Zhong, Jianxin

2016-12-15

Two dimensional Tin Selenide (SnSe) nanosheets (NSs) have been prepared via a facile hydrothermal intercalation and exfoliation route. Morphological test verifies high yield of SnSe NSs with good quality. Additional X-ray diffraction pattern and Raman spectra are carried out and confirm the exfoliated SnSe nanosheet is pure and well crystalized. AFM measurement, along with the SEM images and Raman shifts, reveals few-layers SnSe nanosheet has been successfully obtained after hydrothermal intercalation and exfoliation route. Photoelectrochemical tests also demonstrate the photocurrent density of SnSe NSs is greatly improved compare to that of bulk SnSe. Photocurrent density of exfoliated SnSe NSs can achieve 16 μA/cm{sup 2} when the applied potential is 0.8 V, which is nearly four times higher than that of bulk SnSe. This work demonstrates that the two-dimensional SnSe NSs may have a great potential application in photovoltaic devices.

Synthesis of SnSe nanosheets by hydrothermal intercalation and exfoliation route and their photoresponse properties

International Nuclear Information System (INIS)

Ren, Xiaohui; Qi, Xiang; Shen, Yongzhen; Xu, Guanghua; Li, Jun; Li, Zhenqing; Huang, Zongyu; Zhong, Jianxin

2016-01-01

Two dimensional Tin Selenide (SnSe) nanosheets (NSs) have been prepared via a facile hydrothermal intercalation and exfoliation route. Morphological test verifies high yield of SnSe NSs with good quality. Additional X-ray diffraction pattern and Raman spectra are carried out and confirm the exfoliated SnSe nanosheet is pure and well crystalized. AFM measurement, along with the SEM images and Raman shifts, reveals few-layers SnSe nanosheet has been successfully obtained after hydrothermal intercalation and exfoliation route. Photoelectrochemical tests also demonstrate the photocurrent density of SnSe NSs is greatly improved compare to that of bulk SnSe. Photocurrent density of exfoliated SnSe NSs can achieve 16 μA/cm"2 when the applied potential is 0.8 V, which is nearly four times higher than that of bulk SnSe. This work demonstrates that the two-dimensional SnSe NSs may have a great potential application in photovoltaic devices.

Regulation of proximal-distal intercalation during limb regeneration in the axolotl (Ambystoma mexicanum).

Science.gov (United States)

Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

2010-12-01

Intercalation is the process whereby cells located at the boundary of a wound interact to stimulate proliferation and the restoration of the structures between the boundaries that were lost during wounding. Thus, intercalation is widely considered to be the mechanism of regeneration. When a salamander limb is amputated, the entire cascade of regeneration events is activated, and the missing limb segments and their boundaries (joints) as well as the structures within each segment are regenerated. Therefore, in an amputated limb it is not possible to distinguish between intersegmental regeneration (formation of new segments/joints) and intrasegmental regeneration (formation of structures within a given segment), and it is not possible to study the differential regulation of these two processes. We have used two models for regeneration that allow us to study these two processes independently, and report that inter- and intrasegmental regeneration are different processes regulated by different signaling pathways. New limb segments/joints can be regenerated from cells that dedifferentiate to form blastema cells in response to signaling that is mediated in part by fibroblast growth factor. © 2010 The Authors. Journal compilation © 2010 Japanese Society of Developmental Biologists.

Uniform second Li ion intercalation in solid state ϵ-LiVOPO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Wangoh, Linda W.; Quackenbush, Nicholas F. [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Sallis, Shawn [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Wiaderek, Kamila M.; Ma, Lu; Wu, Tianpin; Chapman, Karena W. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Lin, Yuh-Chieh; Ong, Shyue Ping [Department of NanoEngineering, University of California San Diego, 9500 Gilman Drive 0448, La Jolla, California 92093 (United States); Wen, Bohua; Chernova, Natasha A.; Whittingham, M. Stanley [NECCES, Binghamton University, Binghamton, New York 13902 (United States); Guo, Jinghua [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lee, Tien-Lin; Schlueter, Christoph [Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Piper, Louis F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2016-08-01

Full, reversible intercalation of two Li{sup +} has not yet been achieved in promising VOPO{sub 4} electrodes. A pronounced Li{sup +} gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO{sub 4} cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li{sup +} gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li{sup +} intercalation is a prerequisite for the formation of intermediate phases Li{sub 1.50}VOPO{sub 4} and Li{sub 1.75}VOPO{sub 4}. The evolution from LiVOPO{sub 4} to Li{sub 2}VOPO{sub 4} via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.

Increased risk of post-operative complications in patients with Crohn’s disease treated with anti-tumour necrosis factor α agents - a systematic review

DEFF Research Database (Denmark)

El-Hussuna, Alaa; Theede, Klaus; Olaison, Per Olov Gunnar

2014-01-01

INTRODUCTION: Tumour necrosis factor α (TNF-α) plays a role in the immune defence, angiogenesis and collagen synthesis. Inhibition of these pathways may increase the risk of infections and impair wound healing in patients after surgery. Biologic treatments including anti-TNF-α agents are increasi......INTRODUCTION: Tumour necrosis factor α (TNF-α) plays a role in the immune defence, angiogenesis and collagen synthesis. Inhibition of these pathways may increase the risk of infections and impair wound healing in patients after surgery. Biologic treatments including anti-TNF-α agents...... are increasingly used in the treatment of inflammatory bowel disease. Taking into consideration the biologics' mechanism of action, fears have been expressed that they might increase the rate of post-operative complications. Results from 18 retrospective studies were conflicting, and meta-analyses based...... an increased risk of overall post-operative complications and an increased rate of infectious or anastomosis-related complications in patients receiving anti-TNF-α. CONCLUSION: The use of anti-TNF-α agents in Crohn's disease patients is associated with an increased risk of post-operative complications after...

Incorporation of rare-earth ions in Mg-Al layered double hydroxides: intercalation with an [Eu(EDTA)] - chelate

Science.gov (United States)

Li, Cang; Wang, Ge; Evans, David G.; Duan, Xue

2004-12-01

Reaction of an aqueous slurry of an Mg 2Al-NO 3 layered double hydroxide with a four-fold excess of Na[Eu(EDTA)] gives a material which analyses for Mg 0.68Al 0.32(OH) 2[Eu(EDTA)] 0.10(CO 3) 0.11·0.66H 2O. The interlayer spacing of the material is 13.8 Å, corresponding to a gallery height of 9.0 Å, which accords with the maximal dimensions (9-10 Å) of the anion in metal-EDTA complex salts as determined by single crystal X-ray diffraction. Geometrical considerations show that the charge density on the layered double hydroxide layers is too high to be balanced by intercalation of [Eu(EDTA)] - alone, necessitating the co-intercalation of carbonate ions which have a much higher charge density.

New alkali-metal- and 2-phenethylamine-intercalated superconductors Ax(C8H11N)yFe1-zSe (A = Li, Na) with the largest interlayer spacings and Tc ∼ 40 K

International Nuclear Information System (INIS)

Hatakeda, Takehiro; Noji, Takashi; Sato, Kazuki; Kawamata, Takayuki; Kato, Masatsune; Koike, Yoji

2016-01-01

New FeSe-based intercalation superconductors, A x (C 8 H 11 N) y Fe 1-z Se (A = Li, Na), with T c = 39-44 K have been successfully synthesized via the intercalation of alkali metals and 2-phenethylamine into FeSe. The interlayer spacings, namely, the distances between neighboring Fe layers, d, of A x (C 8 H 11 N) y Fe 1-z Se (A = Li, Na) are 19.04(6) and 18.0(1) Å, respectively. These d values are the largest among those of the FeSe-based intercalation compounds and are understood to be due to the intercalation of two molecules of 2-phenethylamine in series perpendicular to the FeSe layers. It appears that the relationship between T c and d in the FeSe-based intercalation superconductors is not domic but T c is saturated at ∼45 K, which is comparable to the T c values of single-layer FeSe films, for d ≥ 9 Å. (author)

Effects of pH and concentration on ability of Cl and NO to intercalate ...

Indian Academy of Sciences (India)

Wintec

in solution would facilitate the anions' reactions with Mg and Al species to form HTs, resulting in a high de- gree of anion intercalation into the interlayer ... and aromatic compounds from aqueous solutions (Kameda et al 2005a, b, 2006). ..... Lazaridis N K 2003 Water Air and Soil Pollution 146 127. Lukashin A V, Kalinin S V, ...

Intercalation of vanadate in Ni, Zn layered hydroxyacetates

International Nuclear Information System (INIS)

Rojas, Ricardo; Barriga, Cristobalina; Ulibarri, M.A.; Rives, Vicente

2004-01-01

Interlayer acetate anions in layered double hydroxyacetates of Ni 2+ and Zn 2+ have been exchanged by oxovanadates following three synthetic routes (at 60 deg. C, under hydrothermal conditions and after preswelling with caprylate anions) and different pH; direct exchange at room temperature was not successful. Complete exchange was achieved under adequated conditions, and the precise nature of the interlayer anion depends on the pH during exchange: at low pH (4.5), the presence of α-VO 3 chains, with anchoring (grafting) of the species to the hydroxide layers, is proposed. At higher pH (9.5) V 2 O 7 4- species are present in the interlayer. Thermal decomposition of these vanadate-intercalated products leads to formation of orthorhombic Ni 2+ and Zn 2+ vanadates, together with NiO

Intercalated radio-chemotherapy in small cell lung cancer

International Nuclear Information System (INIS)

Hoskin, P.J.; Parton, D.; Yarnold, J.R.; Cherryman, G.; Smith, I.E.

1991-01-01

36 patients with small cell lung cancer have been treated using chemotherapy comprising carboplatin, ifosphamide and etoposide. A total of 6 cycles of chemotherapy was given. In 15 patients with limited disease intercalated radio-chemotherapy was used in which two 5-day courses of hyperfractionated radiotherapy were given to the thorax after the 1st and 2nd cycles of chemotherapy. Each course of thoracic radiotherapy delivered 15 Gy in 15 fractions over 5 days. Oesophagitis occurred in 7 patients (40 percent), in 5 of whom this was severe (WHO grade 3). Radiological pneumonitis developed in 6 patients (40 percent) with subsequent fibrosis in 2 patients. These effects are greater than would be expected with this dose of radiation alone and reflect marked enhancement of normal tissue toxicity. (author). 11 refs.; 1 fig.; 1 tab

Theoretical study on the correlation between the nature of atomic Li intercalation and electrochemical reactivity in TiS2 and TiO2.

Science.gov (United States)

Kim, Yang-Soo; Kim, Hee-Jin; Jeon, Young-A; Kang, Yong-Mook

2009-02-12

The electronic structures of LiTiS(2) and LiTiO(2) (having alpha-NaFeO(2) structure) have been investigated using discrete variational Xalpha molecular orbital methods. The alpha-NaFeO(2) structure is the equilibrium structure for LiCoO(2), which is widely used as a commercial cathode material for lithium secondary batteries. This study especially focused on the charge state of Li ions and the magnitude of covalency around Li ions. When the average voltage of lithium intercalation was calculated using pseudopotential methods, the average intercalation voltage of LiTiO(2) (2.076 V) was higher than that of LiTiS(2) (1.958 V). This can be explained by the differences in Mulliken charge of lithium and the bond overlap population between the intercalated Li ions and anion in LiTiO(2) as well as LiTiS(2). The Mulliken charge, which is the ionicity of Li atom, was approximately 0.12 in LiTiS(2), and the bond overlap population (BOP) indicating the covalency between Ti and S was about 0.339. When compared with the BOP (0.6) of C-H, which is one of the most famous example of covalent bonding, the intercalated Li ions in LiTiS(2) tend to form a quite strong covalent bond with the host material. In contrast, the Mulliken charge of lithium was about 0.79, which means that Li is fully ionized and the BOP, the covalency between Ti and O, was 0.181 in LiTiO(2). Because of the high ionicity of Li and the weak covalency between Ti and the nearest anion, LiTiO(2) has a higher intercalation voltage than LiTiS(2).

Influence of sodium dodecyl sulfate concentration on the photocatalytic activity and dielectric properties of intercalated sodium dodecyl sulfate into Zn–Cd–Al layered double hydroxide

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Abdullah Ahmed Ali, E-mail: abdullah2803@gmail.com [Department of Physics, Faculty of Applied Science, Thamar University, Dhamar 87246 (Yemen); Talib, Zainal Abidin [Department of Physics, Faculty of Science, Universiti Putra Malaysia, UPM, Serdang, Selangor 43400 (Malaysia); Hussein, Mohd Zobir [Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology (ITMA), Universiti Putra Malaysia, UPM, Serdang, Selangor 43400 (Malaysia)

2015-02-15

Highlights: • Zn–Cd–Al–LDH–DS were synthesized with different SDS concentrations. • Photocatalytic activity of samples was improved by increasing SDS concentration. • Dielectric response of LDH can be described by anomalous low frequency dispersion. • The dc conductivity values were calculated for Zn–Cd–Al–LDH–DS samples. • ESR spectra exhibited the successful intercalation of DS molecule into LDH gallery. - Abstract: Sodium dodecyl sulfate (SDS) has been successfully intercalated into Zn–Cd–Al–LDH precursor with different SDS concentrations (0.2, 0.3, 0.4, 0.5 and 1 mol L{sup −1}) using the coprecipitation method at (Zn{sup 2+} + Cd{sup 2+})/Al{sup 3+} molar ratio of 13 and pH 8. The structural, morphological, texture and composition properties of the synthesized (Zn–Cd–Al–LDH–DS) nanostructure were investigated using powder X-ray diffraction (PXRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR), respectively. The photocatalytic activity of these materials was developed by increasing the concentration of intercalated SDS. The absorbance spectra have been used to detect an anion in the LDH interlayer before and after the intercalation process, which confirmed the presence of the dodecyl sulfate (DS{sup −}) anion into LDH gallery after intercalation. The anomalous low frequency dispersion (ALFD) has been used to describe the dielectric response of Zn–Cd–Al–LDH–DS nanostructure using the second type of universal power law. At low frequency, the polarization effect of electrodes caused the rising in dielectric constant and loss values. An important result of the dielectric measurements is the calculated dc conductivity values, which are new in dielectric spectroscopy of LDH materials. An important result of the electron spin resonance (ESR) spectra exhibited the successful intercalation of DS molecule into LDH gallery. The g-factor value was affected by

Spermine attenuates the action of the DNA intercalator, actinomycin D, on DNA binding and the inhibition of transcription and DNA replication.

Science.gov (United States)

Wang, Sheng-Yu; Lee, Alan Yueh-Luen; Lee, Yueh-Luen; Lai, Yi-Hua; Chen, Jeremy J W; Wu, Wen-Lin; Yuann, Jeu-Ming P; Su, Wang-Lin; Chuang, Show-Mei; Hou, Ming-Hon

2012-01-01

The anticancer activity of DNA intercalators is related to their ability to intercalate into the DNA duplex with high affinity, thereby interfering with DNA replication and transcription. Polyamines (spermine in particular) are almost exclusively bound to nucleic acids and are involved in many cellular processes that require nucleic acids. Until now, the effects of polyamines on DNA intercalator activities have remained unclear because intercalation is the most important mechanism employed by DNA-binding drugs. Herein, using actinomycin D (ACTD) as a model, we have attempted to elucidate the effects of spermine on the action of ACTD, including its DNA-binding ability, RNA and DNA polymerase interference, and its role in the transcription and replication inhibition of ACTD within cells. We found that spermine interfered with the binding and stabilization of ACTD to DNA. The presence of increasing concentrations of spermine enhanced the transcriptional and replication activities of RNA and DNA polymerases, respectively, in vitro treated with ActD. Moreover, a decrease in intracellular polyamine concentrations stimulated by methylglyoxal-bis(guanylhydrazone) (MGBG) enhanced the ACTD-induced inhibition of c-myc transcription and DNA replication in several cancer cell lines. The results indicated that spermine attenuates ACTD binding to DNA and its inhibition of transcription and DNA replication both in vitro and within cells. Finally, a synergistic antiproliferative effect of MGBG and ACTD was observed in a cell viability assay. Our findings will be of significant relevance to future developments in combination with cancer therapy by enhancing the anticancer activity of DNA interactors through polyamine depletion.

Spermine attenuates the action of the DNA intercalator, actinomycin D, on DNA binding and the inhibition of transcription and DNA replication.

Directory of Open Access Journals (Sweden)

Sheng-Yu Wang

Full Text Available The anticancer activity of DNA intercalators is related to their ability to intercalate into the DNA duplex with high affinity, thereby interfering with DNA replication and transcription. Polyamines (spermine in particular are almost exclusively bound to nucleic acids and are involved in many cellular processes that require nucleic acids. Until now, the effects of polyamines on DNA intercalator activities have remained unclear because intercalation is the most important mechanism employed by DNA-binding drugs. Herein, using actinomycin D (ACTD as a model, we have attempted to elucidate the effects of spermine on the action of ACTD, including its DNA-binding ability, RNA and DNA polymerase interference, and its role in the transcription and replication inhibition of ACTD within cells. We found that spermine interfered with the binding and stabilization of ACTD to DNA. The presence of increasing concentrations of spermine enhanced the transcriptional and replication activities of RNA and DNA polymerases, respectively, in vitro treated with ActD. Moreover, a decrease in intracellular polyamine concentrations stimulated by methylglyoxal-bis(guanylhydrazone (MGBG enhanced the ACTD-induced inhibition of c-myc transcription and DNA replication in several cancer cell lines. The results indicated that spermine attenuates ACTD binding to DNA and its inhibition of transcription and DNA replication both in vitro and within cells. Finally, a synergistic antiproliferative effect of MGBG and ACTD was observed in a cell viability assay. Our findings will be of significant relevance to future developments in combination with cancer therapy by enhancing the anticancer activity of DNA interactors through polyamine depletion.

Chemically functionalized two-dimensional titanium carbide MXene by in situ grafting-intercalating with diazonium ions to enhance supercapacitive performance

Science.gov (United States)

Wang, Hongbing; Zhang, Jianfeng; Wu, Yuping; Huang, Huajie; Jiang, Quanguo

2018-04-01

Two-dimensional Ti3C2 MXene nanosheets were functionalized with phenylsulfonic groups derived from in situ generated diazonium ions by the corresponding amine. During the functionalization process, the aryl groups were attached onto the MXene surfaces in the form of strong MXene-aryl (Tisbnd Osbnd C) linkages. Simultaneously, the intercalation of diazonium ions enabled Ti3C2 multi-layers to be delaminated into separate few-layer nanosheets via weak sonication with low energy. As a result of chemical functionalization for MXene Ti3C2, the dispersibility was greatly improved and the specific surface area increased significantly. The grafted functional groups are still stable up to at least 200 °C upon thermogravimetric analysis measurements. With diazonium ions intercalating and electroactive groups grafting between-in MXene layers, the chemically functionalized Ti3C2 electrodes exhibited an enhanced supercapacitive performance, which acquired a specific capacitance more than double that of pristine Ti3C2 samples and excellent cycling stability (91% capacity retention after 10,000 cycles at 3 A g-1). This feasible modification scheme can be also extended to functionalize other types of MXenes materials with this or other aryl diazonium ions as surface modifiers and intercalants, thus offering scope for full potential applications of the new 2D materials.

Properties of K,Rb-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods derived from nuclear magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Mahfouz, R. [Division of Physical Sciences & Engineering, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia); Bouhrara, M. [Department of Chemistry, School of Science and Technology, Nazarbayev University, 010000 Astana, Republic of Kazakhstan (Kazakhstan); Kim, Y. [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Wågberg, T. [Department of Physics, Umeå University, 901 87 Umeå (Sweden); Goze-Bac, C. [nanoNMRI Group, UMR5587, Université Montpellier II, Place E. Bataillon, 34095 Montpellier, Cedex 5 (France); Abou-Hamad, E., E-mail: edy.abouhamad@kaust.edu.sa [KAUST Catalysis Center (KCC) King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

2015-09-21

We present a detailed experimental study on how magnetic and electronic properties of Rb,K-intercalated C{sub 60} encapsulated inside carbon nanotubes called peapods can be derived from {sup 13}C nuclear magnetic resonance investigations. Ring currents do play a basic role in those systems; in particular, the inner cavities of nanotubes offer an ideal environment to investigate the magnetism at the nanoscale. We report the largest diamagnetic shifts down to −68.3 ppm ever observed in carbon allotropes, which is connected to the enhancement of the aromaticity of the nanotube envelope upon intercalation. The metallization of intercalated peapods is evidenced from the chemical shift anisotropy and spin-lattice relaxation (T{sub 1}) measurements. The observed relaxation curves signal a three-component model with two slow and one fast relaxing components. We assigned the fast component to the unpaired electrons charged C{sub 60} that show a phase transition near 100 K. The two slow components can be rationalized by the two types of charged C{sub 60} at two different positions with a linear regime following Korringa behavior, which is typical for metallic system and allow us to estimate the density of sate at Fermi level n(E{sub F})

Insights into finding a mismatch through the structure of a mispaired DNA bound by a rhodium intercalator

Science.gov (United States)

Pierre, Valérie C.; Kaiser, Jens T.; Barton, Jacqueline K.

2007-01-01

We report the 1.1-Å resolution crystal structure of a bulky rhodium complex bound to two different DNA sites, mismatched and matched in the oligonucleotide 5′-(dCGGAAATTCCCG)2-3′. At the AC mismatch site, the structure reveals ligand insertion from the minor groove with ejection of both mismatched bases and elucidates how destabilized mispairs in DNA may be recognized. This unique binding mode contrasts with major groove intercalation, observed at a matched site, where doubling of the base pair rise accommodates stacking of the intercalator. Mass spectral analysis reveals different photocleavage products associated with the two binding modes in the crystal, with only products characteristic of mismatch binding in solution. This structure, illustrating two clearly distinct binding modes for a molecule with DNA, provides a rationale for the interrogation and detection of mismatches. PMID:17194756

Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil

OpenAIRE

Colombo, Kamila; Maruyama, Swami A.; Yamamoto, Carlos I.; Wypych, Fernando

2017-01-01

This study reports the synthesis and characterization of a Ni/Zn layered double hydroxide salt intercalated with acetate ions and the subsequent replacement of the acetate ions with molybdate ions via an ion exchange reaction, conducted at two different pH values. Regardless of the pH employed during the synthesis, the basal spacing in the Ni/Zn layered double hydroxide salt decreased from 13.08 Å to approximately 9.5 Å, which agreed with intercalation of hydrated molybdate anions. The non-ca...

Study of the oxidation process of disperse Fe-C containing waste in order to obtain graphite intercalation compounds

Directory of Open Access Journals (Sweden)

Володимир Олександрович Маслов

2016-11-01

Full Text Available Graphite processing into intercalation compounds followed by thermoshock heating is known in literature. The result is an ultra-light dispersed graphite (thermographenit used in lots of industries. Graphite intercalation compounds are formed as a result of the introduction of atomic and molecular layers of different chemical particles between the layers of graphite plates. The object of this work is to obtain a new material by intercalation of graphite followed by thermoshock heating, which could be used for products protecting biological and technical facilities from electromagnetic and thermal radiation. In the present work the parameters of oxidation and of graphite thermoshock expansion in order to obtain graphite intercalation compounds and thermographenit were investigated. The experiments were performed under laboratory non-isothermal conditions. Graphite GAK-2 obtained from metallurgical wastes was used. First the fraction of +0,16 mm with the ash content of 0,3% was extracted by scattering. The oxidation of graphite was carried out by potassium bichromate dissolved in concentrated sulphuric acid. The original sample of graphite was mixed with finely grounded potassium bichromate. Then this mass was poured over with 98% concentrated sulphuric acid when being actively stirred and kept. Then the capacitance for oxidation was filled with distilled water. Decantation was carried out until pH=7 in the waste water was got. Separation of the oxidized graphite from the main mass of water was carried out by means of a suction filter until pH=7 was got. Experiments were performed at different ratios of potassium bichromate, sulphuric acid and graphite. The optimum ratio of the components (sulphuric acid : (dichromate of potash : (graphite = 2,8 : 0,15 : 1 was found. The oxidation time was 4–5 minutes. The oxidized graphite turned into thermographenit with bulk density of 2,7–9,5 kg/m3.upon subsequent heating up to 1000oC within the regime of

Lymphocyte-conditioned medium in combination with interleukin-2 effectively induces antitumour autoimmunity by adoptive transfer of short activated killer (SHAK) cells.

Science.gov (United States)

Buer, J; Hilse, R; Dallmann, I; Grosse, J; Kirchner, H; Zorn, U; Hänninen, E L; Franzke, A; Duensing, S; Poliwoda, H

1995-03-01

In this study, effective antitumour immunity was transferred by autologous short activated killer (SHAK) cells induced over four hours with lymphocyte conditioned medium (LCM) and recombinant interleukin-2 (rIL-2). Among eight patients with progressive metastatic renal cell carcinoma refractory to standard therapy, there were six objective tumour responses to SHAKs. Progression-free survival ranged from 0 to 8+ months, and overall survival ranged from 2 to 14+ months, with a median of 9+ months. Systemic toxicity of SHAKs was limited to flulike symptoms. Patient SHAKs provided a tumour-specific immunity, both cellular and humoral (expression and secretion of secondary cytokines, including IL-2, GM-CSF, INF-gamma and TNF-alpha), far superior to rIL-2 activated killer cells.

Etchant-free graphene transfer using facile intercalation of alkanethiol self-assembled molecules at graphene/metal interfaces.

Science.gov (United States)

Ohtomo, Manabu; Sekine, Yoshiaki; Wang, Shengnan; Hibino, Hiroki; Yamamoto, Hideki

2016-06-02

We report a novel etchant-free transfer method of graphene using the intercalation of alkanethiol self-assembled monolayers (SAMs) at the graphene/Cu interfaces. The early stage of intercalation proceeds through graphene grain boundaries or defects within a few seconds at room temperature until stable SAMs are formed after a few hours. The formation of SAMs releases the compressive strain of graphene induced by Cu substrates and make graphene slightly n-doped due to the formation of interface dipoles of the SAMs on metal surfaces. After SAM formation, the graphene is easily delaminated off from the metal substrates and transferred onto insulating substrates. The etchant-free process enables us to decrease the density of charged impurities and the magnitude of potential fluctuation in the transferred graphene, which suppress scattering of carriers. We also demonstrate the removal of alkanethiol SAMs and reuse the substrate. This method will dramatically reduce the cost of graphene transfer, which will benefit industrial applications such as of graphene transparent electrodes.

Pro-inflammatory cytokine/chemokine production by reovirus treated melanoma cells is PKR/NF-κB mediated and supports innate and adaptive anti-tumour immune priming

Directory of Open Access Journals (Sweden)

Coffey Matt

2011-02-01

Full Text Available Abstract Background As well as inducing direct oncolysis, reovirus treatment of melanoma is associated with activation of innate and adaptive anti-tumour immune responses. Results Here we characterise the effects of conditioned media from reovirus-infected, dying human melanoma cells (reoTCM, in the absence of live virus, to address the immune bystander potential of reovirus therapy. In addition to RANTES, IL-8, MIP-1α and MIP-1β, reovirus-infected melanoma cells secreted eotaxin, IP-10 and the type 1 interferon IFN-β. To address the mechanisms responsible for the inflammatory composition of reoTCM, we show that IL-8 and IFN-β secretion by reovirus-infected melanoma cells was associated with activation of NF-κB and decreased by pre-treatment with small molecule inhibitors of NF-κB and PKR; specific siRNA-mediated knockdown further confirmed a role for PKR. This pro-inflammatory milieu induced a chemotactic response in isolated natural killer (NK cells, dendritic cells (DC and anti-melanoma cytotoxic T cells (CTL. Following culture in reoTCM, NK cells upregulated CD69 expression and acquired greater lytic potential against tumour targets. Furthermore, melanoma cell-loaded DC cultured in reoTCM were more effective at priming adaptive anti-tumour immunity. Conclusions These data demonstrate that the PKR- and NF-κB-dependent induction of pro-inflammatory molecules that accompanies reovirus-mediated killing can recruit and activate innate and adaptive effector cells, thus potentially altering the tumour microenvironment to support bystander immune-mediated therapy as well as direct viral oncolysis.

Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol

Energy Technology Data Exchange (ETDEWEB)

Worcester, D.L.; Hamacher, K.; Kaiser, H.; Kulasekere, R.; Torbet, J. [Univ. of Missouri, Columbia, MO (United States)

1994-12-31

Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer.