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Sample records for well-defined study groups

  1. Well-defined (co)polypeptides bearing pendant alkyne groups

    KAUST Repository

    Zhao, Wei

    2016-03-18

    A novel metal-free strategy, using hydrogen-bonding catalytic ring opening polymerization of acetylene-functionalized N-carboxy anhydrites of α-amino acids, was developed for the synthesis of well-defined polypeptides bearing pendant alkyne groups. This method provides an efficient way to synthesize novel alkyne-functionalized homopolypeptides (A) and copolypeptides, such as AB diblock (B: non-functionalized), ABA triblock and star-AB diblock, as well as linear and star random copolypeptides, precursors of a plethora complex macromolecular architectures by click chemistry.

  2. The Demand-Control Model: Specific demands, specific Control, and well-defined groups

    NARCIS (Netherlands)

    Jonge, J. de; Dollard, M.F.; Dormann, C.; Blanc, P.M.; Houtman, I.L.D.

    2000-01-01

    The purpose of this study was to test the Demand-Control Model (DCM), accompanied by three goals. Firstly, we used alternative, more focused, and multifaceted measures of both job demands and job control that are relevant and applicable to today's working contexts. Secondly, this study intended to

  3. Well-defined linear Au n (n = 2-4) chains encapsulated in SWCNTs: a DFT study.

    Science.gov (United States)

    Liu, Yiliang; Hua, Yawen; Yan, Anying; Wu, Shuang; Kong, Fanjie

    2017-01-01

    One-dimensional (1D) gold nanostructures have been extensively studied due to their potential applications in nanoelectronic devices. Using first-principles calculations, composites consisting of a well-defined linear Au n (n = 2-4) chain encapsulated in a (9,0) single-walled carbon nanotube (SWCNT) were studied. The translational energy barrier of a single Au atom in a (9,0) SWCNT was found to be 0.03 eV. This low barrier guaranteed the formation of Au n @ (9,0) SWCNT (n = 1-4) composites. Bond lengths, differential charge densities, and electronic band structures of the composites were studied. The average Au-Au bond lengths in the composites were found to be almost the same as those in the corresponding free-standing linear Au n . The average bond length increased as the number of Au atoms increased. Charge transfer in all of these composites was slight, although a few valence electrons were transferred from the (9,0) SWCNT and the Au chains to intercalations. The conductivities of the encapsulated linear Au n (n = 2-4) chains were enhanced to some extent by encapsulating them in the SWCNT.

  4. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  5. Solid-State NMR and DFT Studies on the Formation of Well-Defined Silica-Supported Tantallaaziridines: From Synthesis to Catalytic Application

    KAUST Repository

    Hamzaoui, Bilel

    2016-01-27

    Single-site, well-defined, silica-supported tantallaaziridine intermediates [≡Si-O-Ta(η2-NRCH2)(NMe2)2] [R=Me (2), Ph (3)] were prepared from silica-supported tetrakis(dimethylamido)tantalum [≡Si-O-Ta(NMe2)4] (1) and fully characterized by FTIR spectroscopy, elemental analysis, and 1H,13C HETCOR and DQ TQ solid-state (SS) NMR spectroscopy. The formation mechanism, by β-H abstraction, was investigated by SS NMR spectroscopy and supported by DFT calculations. The C-H activation of the dimethylamide ligand is favored for R=Ph. The results from catalytic testing in the hydroaminoalkylation of alkenes were consistent with the N-alkyl aryl amine substrates being more efficient than N-dialkyl amines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Design and characterization of well-defined supramolecular polymers

    Science.gov (United States)

    Schaefer, Kathleen; Kade, Matthew; Hawker, Craig; Kramer, Edward

    2007-03-01

    Polymeric materials with well-defined and controllable temperature dependent properties are of interest both for technological applications and fundamental physical studies. Melt processing requires low viscosity, while resistance to fracture is desirable at material operating temperatures, and these two properties are often mutually exclusive. Through controlled radical polymerization (ATRP) we have synthesized tailor-made polymers with MHB groups specifically located at one or both chain ends or randomly along the backbone to provide thermal tunability, and by changing the nature of the MHB group (complementary or self-complementary) we can control the specificity and type of the polymer-polymer interaction. As a simple model system, we investigate the case of two end-functional MHB homopolymers that form a novel supramolecular diblock copolymer. Two energies are expected to be important in this system---χN, the Flory-Huggins interaction parameter times the degree of polymerization, which describes the polymer-polymer interaction, and ɛ, the binding energy of the MHB group. Using deuterium labeled polymers in various multilayer thin film structures, dynamic secondary ion mass spectrometry (dSIMS) allows each of these parameters to be measured independently and these values used to design technologically and physically interesting new materials.

  7. Breast cancer in situ. From pre-malignant lesion of uncertain significance to well-defined non-invasive malignant lesion. The Danish Breast Cancer Cooperative Group Register 1977-2007 revisited

    DEFF Research Database (Denmark)

    Laenkholm, A.V.; Jensen, Maiken Brit; Kroman, N.;

    2008-01-01

    In addition to nationwide standardized pathology forms for operable primary invasive breast cancer, the Danish Breast Cancer cooperative Group (DBCG) in 1982 introduced pathology forms for breast cancer in situ (CIS). The histological reporting form was used primarily for ductal cancer in situ...... the pleomorphic subtype of LCIS was added to histological subtypes. The present work reviews the DBCG guidelines and recommendations concerning CIS adding a brief characterization of the Danish CIS population. It also refers to the introduction of modern molecular pathology and distinction between low...

  8. Well-Defined Triblock Copolymer Containing Perfluoro- cyclobutyl Aryl Ether and Poly(acrylic acid) Segments

    Institute of Scientific and Technical Information of China (English)

    陆国林; 张森; 李永军; 黄晓宇

    2011-01-01

    A novel well-defined triblock copolymer containing perfluorocyclobutyl group was prepared by the combination of mechanism transformation strategy, thermal cycloaddition [2π+2π] polymerization and atom transfer radical polymerization (ATRP). Firstly, a macroinitiator with two ATRP initiating end groups was synthesized by thermal polymerization of 4,4'-bis-(trifluorovinyloxy)biphenyl (BTFVBP) and sequential end-capping with a difunctional compound containing trifluorovinyl and ATRP initiation group. Secondly, this macroinitiator initiated ATRP of t-butyl acrylate to synthesize PtBA-b-PBTFVBP-b-PtBA triblock copolymer. This copolymer was hydrolyzed to afford PAA-b-PBTFVBP-b-PAA amphiphilic triblock copolymer. This kind of fluorine-containing well-defined structure should benefit the study of self-assembly behaviors.

  9. Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials

    KAUST Repository

    Alyami, Mram Z.

    2016-11-01

    Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

  10. Single-dose pharmacokinetic study of lycopene delivered in a well-defined food-based lycopene delivery system (tomato paste-oil mixture) in healthy adult male subjects.

    Science.gov (United States)

    Gustin, David M; Rodvold, Keith A; Sosman, Jeffery A; Diwadkar-Navsariwala, Veda; Stacewicz-Sapuntzakis, Maria; Viana, Marlos; Crowell, James A; Murray, Judith; Tiller, Patricia; Bowen, Phyllis E

    2004-05-01

    This report details the findings of a single-dose Phase I pharmacokinetic and toxicity study of a food-based formulation of lycopene in healthy adult male subjects. Five dosing groups (n = 5 per group) were sequentially treated with increasing doses of lycopene ranging from 10 to 120 mg. Blood samples were collected for a total of 28 days (672 h) after administration of single doses of lycopene. The mean time (t(max)) to reach maximum total lycopene concentration (C(max)) ranged from 15.6 to 32.6 h. The C(max) for total lycopene ranged between 4.03 and 11.27 microg/dl (0.075-0.210 microm). Mean AUC(0-96) and elimination half-life for total lycopene ranged from 214 to 655 microg h/dl (3.986-12.201 micromol h/l) and 28.1 and 61.6 h, respectively. The changes observed in lycopene exposure parameters (e.g., C(max) and AUC(0-96)) were not proportional to increments in dose, with larger increases observed at the lowest end of the dosing range (10-30 mg). Chylomicron lycopene was measured during the first 12 h with the differences observed among the dosing groups not reaching statistical significance. These findings may reflect a process of absorption that is saturable at very low dosing levels or may be explained by the large interindividual variability in attained lycopene concentrations that were observed within each dosing group. Pharmacokinetic parameters for trans- and cis-lycopene isomers were calculated and are reported here. The formulation was well tolerated with minimal side effects, which were mainly of gastrointestinal nature and of very low grade.

  11. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner....... Subsequently, the immunomodulating substance is also bound in a chemoselective manner, to give a dendrimer conjugate with a well-defined structure and connectivity and containing a precise, pre-determined ratio of carbohydrate to immunomodulating substance. The invention also relates to novel dendrimer...

  12. A Generic Synthesis Algorithm for Well-Defined Parametric Design

    NARCIS (Netherlands)

    Schotborgh, W.O.; Kokkeler, F.G.M.; Tragter, H.; Bomhoff, M.J.; Houten, van F.J.A.M.

    2008-01-01

    This paper aims to improve the way synthesis tools can be built by formalizing: 1) the design artefact, 2) related knowledge and 3) an algorithm to generate solutions. This paper focuses on well-defined parametric engineering design, ranging from machine elements to industrial products. A design art

  13. Well-defined transition metal hydrides in catalytic isomerizations.

    Science.gov (United States)

    Larionov, Evgeny; Li, Houhua; Mazet, Clément

    2014-09-07

    This Feature Article intends to provide an overview of a variety of catalytic isomerization reactions that have been performed using well-defined transition metal hydride precatalysts. A particular emphasis is placed on the underlying mechanistic features of the transformations discussed. These have been categorized depending upon the nature of the substrate and in most cases discussed following a chronological order.

  14. Volumetric flame synthesis of well-defined molybdenum oxide nanocrystals.

    Science.gov (United States)

    Merchan-Merchan, Wilson; Saveliev, Alexei V; Desai, Milind

    2009-11-25

    Well-defined faceted inorganic Mo oxide nanocrystals are synthesized in the gas phase using a solid-fed-precursor flame synthesis method. The solid crystals have rectangular cross-section with characteristic size of 10-20 nm and with lengths ranging from 50 nm to a few hundred nanometres. A 1 mm diameter high purity Mo probe introduced in the oxygen-rich part of the flame serves as the material source. A combination of the strong temperature gradient and varying chemical species concentrations within the flame volume provides the ideal conditions for the rapid and direct formation of these unique nanocrystals. Oxidation and evaporation of MoO3 in the oxygen-rich zone are followed by reduction to MoO2 in the lower temperature, more fuel-rich zone. The MoO3 vapours formed are pushed in the direction of the gas flow and transformed into mature well-defined convex polyhedron nanocrystals bounded with six faces resembling rectangular parallelepipeds.

  15. Volumetric flame synthesis of well-defined molybdenum oxide nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Merchan-Merchan, Wilson; Desai, Milind [School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK 73019 (United States); Saveliev, Alexei V, E-mail: wmerchan-merchan@ou.ed [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2009-11-25

    Well-defined faceted inorganic Mo oxide nanocrystals are synthesized in the gas phase using a solid-fed-precursor flame synthesis method. The solid crystals have rectangular cross-section with characteristic size of 10-20 nm and with lengths ranging from 50 nm to a few hundred nanometres. A 1 mm diameter high purity Mo probe introduced in the oxygen-rich part of the flame serves as the material source. A combination of the strong temperature gradient and varying chemical species concentrations within the flame volume provides the ideal conditions for the rapid and direct formation of these unique nanocrystals. Oxidation and evaporation of MoO{sub 3} in the oxygen-rich zone are followed by reduction to MoO{sub 2} in the lower temperature, more fuel-rich zone. The MoO{sub 3} vapours formed are pushed in the direction of the gas flow and transformed into mature well-defined convex polyhedron nanocrystals bounded with six faces resembling rectangular parallelepipeds.

  16. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization(ATRP)macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into ATRP macroinitiators.Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined,densely grafted outer polystyrene by ATRP,which was initiated by the as-synthesized silica-based macroinitiator.FTIR,NMR and gel permeation chromatography(GPC)were used to characterize the polystyrene/silica hybrid particles.

  17. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization (ATRP) macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate (TDI), after which the residual isocyanate groups were converted into ATRP macroinitiators. Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined, densely grafted outer polystyrene by ATRP, which was initiated by the as-synthesized silica-based macroinitiator. FTIR, NMR and gel permeation chro-matography (GPC) were used to characterize the polystyrene/silica hybrid particles.

  18. Efficient Construction of Well-Defined Multicompartment Porous Systems in a Modular and Chemically Orthogonal Fashion.

    Science.gov (United States)

    Gao, Ning; Tian, Tian; Cui, Jiecheng; Zhang, Wanlin; Yin, Xianpeng; Wang, Shiqiang; Ji, Jingwei; Li, Guangtao

    2017-03-27

    A microfluidic assembly approach was developed for efficiently producing hydrogel spheres with reactive multidomains that can be employed as an advantageous platform to create spherical porous networks in a facile manner with well-defined multicompartments and spatiotemporally controlled functions. This strategy allows for not only large scale fabrication of various robust hydrogel microspheres with controlled size and porosity, but also the domains embedded in hydrogel network could be introduced in a modular manner. Additionally, the number of different domains and their ratio could be widely variable on demand. More importantly, the reactive groups distributed in individual domains could be used as anchor sites to further incorporate functional units in an orthogonal fashion, leading to well-defined multicompartment systems. The strategy provides a new and efficient route to construct well-defined functional multicompartment systems with great flexibility and extendibility. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Method of preparing well-defined polypeptides via rop

    KAUST Repository

    Hadjichristidis, Nikolaos

    2015-09-24

    A process for living ring-opening polymerization can include exposing an N- carboxyanhydride monomer to an initiator that includes a first primary amine covalently linked to a first electron donor by a first linking group to form a polyamide polymer. The initiator can include a second primary amine, optionally a second electron donor, and optionally a third electron donor.

  20. LADDER SUPERSTRUCTURE-DIRECTED SYNTHESIS OF A WELL-DEFINED m-PHENELENEDIIMINO-BRIDGED LADDER POLYMETHYLSILOXANE

    Institute of Scientific and Technical Information of China (English)

    Yin-sheng Lv; Zhong-jie Ren; You-zhi Wan; Ping Xie; Rong-ben Zhang

    2009-01-01

    A well-defined m-phenylenediimino-bridged ladder polymethylsiloxane (LP) was first synthesized through a well-defined ladder superstructure (LS) acting as synthetic template, which was self-assembled by concerted interaction of hydrogen bonding and aromatic π-π stacking of the monomer (M), N,N'-bis(phenyldichlorosilyl)-m-phenylenediamine. Some key characterization data of LP and, in particular, the extremely vulnerable LS with very unstable Si--Cl and Si-N groups were given. The molecular weights (Mn) of LS and LP are 5010 and 10480, corresponding to about 15 and 46 monomer units, respectively. To monitor the real in situ status of LS in solution the XRD measurements of special freeze-drying samples were performed, demonstrating two characteristic peaks of ladder structure. Most importantly, both LP and LS display exceedingly sharp resonance absorption peaks with a half peak width (△1/2) as small as < 0.3 of MeSi(NH)O2/2 moieties in 29Si-NMR spectra. It is well-known that the higher the regularity of the ladder polysiloxane, the narrower the resonance peak of the siloxane moiety on the ladder backbone, and the smaller the half peak width △1/2. Therefore, the very small values of △1/2 for both LS and LP confirm that both LS and LP possess well-defined ladder structures.

  1. Well-defined polyethylene molecular brushes by polyhomologation and ring opening metathesis polymerization

    KAUST Repository

    Zhang, Hefeng

    2014-01-01

    A novel strategy using polyhomologation and ring opening metathesis polymerization (ROMP) has been developed for the synthesis of well-defined polyethylene (PE) molecular brushes. Polyhomologation was used to afford an OH-terminated PE, which after transformation to the norbornyl PE macromonomer was subjected to ROMP. Kinetics of ROMP of the PE macromonomer was studied by in situ1H NMR monitoring. The brush structure was proved from HT-GPC, 1H NMR and DSC results.

  2. Preparation of Bimetallic PtnPdm Supported Clusters with Well-Defined Stoichiometry

    Science.gov (United States)

    Rousset, J. L.; Cadrot, A. M.; Aires, F. Santos; Renouprez, A.; Mélinon, P.; Perez, A.; Pellarin, M.; Vialle, J. L.; Broyer, M.

    Supported bimetallic Pd-Pt clusters with a well-defined stoichiometry are produced using a laser-vaporization source. Free clusters are also studied by time-of-flight mass spectrometry and photofragmentation. The supported clusters are characterized by energy dispersive x-ray analysis. The low binding energy of palladium atoms compared to that of platinum is clearly demonstrated in both free and supported clusters. The reactivity is briefly discussed.

  3. Cytochrome c Can Form a Well-Defined Binding Pocket for Hydrocarbons.

    Science.gov (United States)

    McClelland, Levi J; Steele, Harmen B B; Whitby, Frank G; Mou, Tung-Chung; Holley, David; Ross, J B Alexander; Sprang, Stephen R; Bowler, Bruce E

    2016-12-28

    Cytochrome c can acquire peroxidase activity when it binds to cardiolipin in mitochondrial membranes. The resulting oxygenation of cardiolipin by cytochrome c provides an early signal for the onset of apoptosis. The structure of this enzyme-substrate complex is a matter of considerable debate. We present three structures at 1.7-2.0 Å resolution of a domain-swapped dimer of yeast iso-1-cytochrome c with the detergents, CYMAL-5, CYMAL-6, and ω-undecylenyl-β-d-maltopyranoside, bound in a channel that places the hydrocarbon moieties of these detergents next to the heme. The heme is poised for peroxidase activity with water bound in place of Met80, which serves as the axial heme ligand when cytochrome c functions as an electron carrier. The hydroxyl group of Tyr67 sits 3.6-4.0 Å from the nearest carbon of the detergents, positioned to act as a relay in radical abstraction during peroxidase activity. Docking studies with linoleic acid, the most common fatty acid component of cardiolipin, show that C11 of linoleic acid can sit adjacent to Tyr67 and the heme, consistent with the oxygenation pattern observed in lipidomics studies. The well-defined hydrocarbon binding pocket provides atomic resolution evidence for the extended lipid anchorage model for cytochrome c/cardiolipin binding. Dimer dissociation/association kinetics for yeast versus equine cytochrome c indicate that formation of mammalian cytochrome c dimers in vivo would require catalysis. However, the dimer structure shows that only a modest deformation of monomeric cytochrome c would suffice to form the hydrocarbon binding site occupied by these detergents.

  4. Lipid mixtures prepared with well-defined synthetic ceramides closely mimic the unique stratum corneum lipid phase behavior.

    Science.gov (United States)

    de Jager, Miranda W; Gooris, Gert S; Ponec, Maria; Bouwstra, Joke A

    2005-12-01

    Lipid lamellae present in the outermost layer of the skin, the stratum corneum, form the main barrier for the diffusion of molecules through the skin. The presence of a unique 13 nm lamellar phase and its high crystallinity are characteristic for the stratum corneum lipid phase behavior. In the present study, small-angle and wide-angle X-ray diffraction were used to examine the organization in lipid mixtures prepared with a unique set of well-defined synthetic ceramides, varying from each other in head group architecture and acyl chain length. The results show that equimolar mixtures of cholesterol, free fatty acids, and synthetic ceramides (resembling the composition of pig ceramides) closely resemble the lamellar and lateral stratum corneum lipid organization, both at room and higher temperatures. Exclusion of several ceramide classes from the mixture does not affect the lipid organization. However, complete substitution of ceramide 1 (acylceramide with a sphingosine base) with ceramide 9 (acylceramide with a phytosphingosine base) reduces the formation of the long periodicity lamellar phase. This indicates that the head group architecture of acylceramides affects the lipid organization. In conclusion, lipid mixtures prepared with well-defined synthetic ceramides offer an attractive tool with which to unravel the importance of the molecular structure of individual ceramides for proper lipid organization.

  5. Well-Defined Cyclic Triblock Terpolymers: A Missing Piece of the Morphology Puzzle

    KAUST Repository

    Polymeropoulos, George

    2016-10-27

    Two well-defined cyclic triblock terpolymers, missing pieces of the terpolymer morphology puzzle, consisting of poly(isoprene), polystyrene, and poly(2-vinylpyridine), were synthesized by combining the Glaser coupling reaction with anionic polymerization. An α,ω-dihydroxy linear triblock terpolymer (OH-PI1,4-b-PS-b-P2VP-OH) was first synthesized followed by transformation of the OH to alkyne groups by esterification with pentynoic acid and cyclization by Glaser coupling. The size exclusion chromatography (SEC) trace of the linear terpolymer precursor was shifted to lower elution time after cyclization, indicating the successful synthesis of the cyclic terpolymer. Additionally, the SEC trace of the cyclic terpolymer produced, after cleavage of the ester groups, shifted again practically to the position corresponding to the linear precursor. The first exploratory results on morphology showed the tremendous influence of the cyclic structure on the morphology of terpolymers. © 2016 American Chemical Society.

  6. Large and well-defined Rabi splitting in a semiconductor nanogap cavity.

    Science.gov (United States)

    Uemoto, Mitsuharu; Ajiki, Hiroshi

    2014-09-22

    We propose a nanogap structure composed of semiconductor nanoparticles forming an optical cavity. The resonant excitation of excitons in the nanoparticles can generate a localized strong light field in the gap region, also called "hot spot". The spectral width of the hot spot is significantly narrow because of the small exciton damping and the dephasing at low temperature, so the semiconductor nanogap structure acts as a high-Q cavity. In addition, the interaction between light and matter at the nanogap is significantly larger than that in a conventional microcavity, because the former has a small cavity-mode volume beyond the diffraction limit. We theoretically demonstrate the large and well-defined vacuum-Rabi splitting of a two-level emitter placed inside the semiconductor nanogap cavity: the Rabi splitting energy of 1.7 meV for the transition dipole moment of the emitter (25 Debye) is about 6.3 times larger than the spectral width. An optical cavity providing such a large and well-defined Rabi splitting is highly suited for studying characteristic features of the cavity quantum electrodynamics and for the development of new applications.

  7. Challenging nature's monopoly on the creation of well-defined nanoparticles.

    Science.gov (United States)

    Jeong, Wonhee; Napier, Mary E; DeSimone, Joseph M

    2010-06-01

    Nature has selected and fine-tuned the physical and chemical properties of natural objects, such as size, shape, mechanical properties and surface chemistry, at the molecular level in order to modulate biological functions. A new particle fabrication process, particle replication in nonwetting templates (PRINT), has recently begun to attempt to emulate nature's ability to control those physical and chemical traits. The PRINT technology, which combines modern soft lithography with the unique properties of perfluoropolyether molds, enables the production of nanoparticles with unprecedented control of size, shape, chemical composition, deformability and surface functionality. This scalable 'top-down' fabrication process allows for the generation of well-defined nanostructures without the need for molecular assembly. The ability to flexibly engineer various matrix materials offers unique opportunities for the development of nanomedicines with desired functionality. The strength and versatility of PRINT makes it a powerful platform in nanomedicine for elucidating the role of physical and chemical properties of nanodelivery vehicles on the behavior and fate at the cellular, tissue and whole organism level. Utilizing the PRINT technology, we are generating well-defined nanomedicines with tailored properties for preclinical studies against a variety of human diseases.

  8. Well-defined hydrophilic molecularly imprinted polymer microspheres for efficient molecular recognition in real biological samples by facile RAFT coupling chemistry.

    Science.gov (United States)

    Zhao, Man; Chen, Xiaojing; Zhang, Hongtao; Yan, Husheng; Zhang, Huiqi

    2014-05-12

    A facile and highly efficient new approach (namely RAFT coupling chemistry) to obtain well-defined hydrophilic molecularly imprinted polymer (MIP) microspheres with excellent specific recognition ability toward small organic analytes in the real, undiluted biological samples is described. It involves the first synthesis of "living" MIP microspheres with surface-bound vinyl and dithioester groups via RAFT precipitation polymerization (RAFTPP) and their subsequent grafting of hydrophilic polymer brushes by the simple coupling reaction of hydrophilic macro-RAFT agents (i.e., hydrophilic polymers with a dithioester end group) with vinyl groups on the "living" MIP particles in the presence of a free radical initiator. The successful grafting of hydrophilic polymer brushes onto the obtained MIP particles was confirmed by SEM, FT-IR, static contact angle and water dispersion studies, elemental analyses, and template binding experiments. Well-defined MIP particles with densely grafted hydrophilic polymer brushes (∼1.8 chains/nm(2)) of desired chemical structures and molecular weights were readily obtained, which showed significantly improved surface hydrophilicity and could thus function properly in real biological media. The origin of the high grafting densities of the polymer brushes was clarified and the general applicability of the strategy was demonstrated. In particular, the well-defined characteristics of the resulting hydrophilic MIP particles allowed the first systematic study on the effects of various structural parameters of the grafted hydrophilic polymer brushes on their water-compatibility, which is of great importance for rationally designing more advanced real biological sample-compatible MIPs.

  9. Well-defined biobased segmented polyureas synthesis via a TBD-catalyzed isocyanate-free route.

    Science.gov (United States)

    Tang, Donglin; Mulder, Dirk-Jan; Noordover, Bart A J; Koning, Cor E

    2011-09-01

    Via an isocyanate-free route, a series of segmented polyureas (PUs) were synthesized from (potentially) renewable resources. To the best of our knowledge, the present work shows for the first time that the organic superbase guanidine 1,5,7-triazabicyclododecene (TBD) which was originally developed as a catalyst for the ring-opening polymerization of lactones, lactides or cyclic carbonates, is also a promising catalyst for the transurethanization between dicarbamates and diamino-terminated poly(propylene glycol) (PPGda) providing PUs via an isocyanate-free strategy. The renewable segmented PUs contain monodisperse hard segments (HSs). This well-defined structure was verified by the DMTA plots of the PUs, showing a sharp glass transition, a sharp flow transition and a flat rubbery plateau. The flow and maximum use temperature (Tfl ) of the PUs increases with the increasing number of urea groups in the corresponding dicarbamates. In addition, at constant HS length, the length of the soft-segment (SS) can be changed to adjust the properties of the PU materials, enabling their application as adhesives, soft elastomers, or rigid plastics.

  10. Structure-function relationship of anticoagulant and antithrombotic well-defined sulfated polysaccharides from marine invertebrates.

    Science.gov (United States)

    Pomin, Vitor H

    2012-01-01

    Marine sulfated polysaccharides (MSPs), such as sulfated fucans (SFs), sulfated galactans (SGs), and glycosaminoglycans (GAGs) isolated from invertebrate animals, are highly anionic polysaccharides capable of interacting with certain cationic proteins, such as (co)-factors of the coagulation cascade during clotting-inhibition process. Primarily, these molecular complexes between MSPs and coagulation-related proteins seem to be driven mostly by electrostatic interactions. However, through a systematic comparison using several novel well-defined sulfated polysaccharides composed of repetitive oligosaccharides with clear sulfation patterns, it was proved that those molecular interactions are essentially regulated by the stereochemistry of the glycans (which depends on a conjunction of anomeric configurations, sugar types, conformational preferences, glycosylation, and sulfation sites), rather than just a mere consequence of the electronegative density charges (mainly from number of sulfate groups). Here, we present an overview about the structure-function relationship of the invertebrate MSPs with regular structures as potential anticoagulant and antithrombotic agents, as pathologies related to the cardiovascular system are one of the major causes of mortality in the world.

  11. Correlation of Theory and Function in Well-Defined Bimetallic Electrocatalysts - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Richard M.

    2014-06-05

    The objective of this research proposal was to correlate the structure of nanoparticles that are comprised of ~100-200 atoms to their electrocatalytic function. This objective was based on the growing body of evidence suggesting that catalytic properties can be tailored through controlled synthesis of nanoparticles. What has been missing from many of these studies, and what we are contributing, is a model catalyst that is sufficiently small, structurally well-defined, and well-characterized that its function can be directly predicted by theory. Specifically, our work seeks to develop a fundamental and detailed understanding of the relationship between the structure of nanoscopic oxygen-reduction catalysts and their function. We assembled a team with expertise in theory, synthesis, and advanced characterization methods to address the primary objective of this project. We anticipated the outcomes of the study to be: (1) a better theoretical understanding of how nanoparticle structure affects catalytic properties; (2) the development of advanced, in-situ and ex-situ, atomic-scale characterization methods that are appropriate for particles containing about 100 atoms; and (3) improved synthetic methods that produce unique nanoparticle structures that can be used to test theoretical predictions. During the project period, we have made excellent progress on all three fronts.

  12. Catalysis by Design: Well-Defined Single-Site Heterogeneous Catalysts

    KAUST Repository

    Pelletier, Jeremie

    2016-03-09

    ConspectusHeterogeneous catalysis, a field important industrially and scientifically, is increasingly seeking and refining strategies to render itself more predictable. The main issue is due to the nature and the population of catalytically active sites. Their number is generally low to very low, their "acid strengths" or " redox properties" are not homogeneous, and the material may display related yet inactive sites on the same material. In many heterogeneous catalysts, the discovery of a structure-activity reationship is at best challenging. One possible solution is to generate single-site catalysts in which most, if not all, of the sites are structurally identical. Within this context and using the right tools, the catalyst structure can be designed and well-defined, to reach a molecular understanding. It is then feasible to understand the structure-activity relationship and to develop predictable heterogeneous catalysis. Single-site well-defined heterogeneous catalysts can be prepared using concepts and tools of surface organometallic chemistry (SOMC). This approach operates by reacting organometallic compounds with surfaces of highly divided oxides (or of metal nanoparticles). This strategy has a solid track record to reveal structure-activity relationship to the extent that it is becoming now quite predictable. Almost all elements of the periodical table have been grafted on surfaces of oxides (from simple oxides such as silica or alumina to more sophisticated materials regarding composition or porosity).Considering catalytic hydrocarbon transformations, heterogeneous catalysis outcome may now be predicted based on existing mechanistic proposals and the rules of molecular chemistry (organometallic, organic) associated with some concepts of surface sciences. A thorough characterization of the grafted metal centers must be carried out using tools spanning from molecular organometallic or surface chemistry. By selection of the metal, its ligand set, and the

  13. Microwave-controlled facile synthesis of well-defined PbS hexapods.

    Science.gov (United States)

    Chen, Ganchao; Fan, Junbing; Zhao, Tian; Xu, Xiaobo; Zhu, Mingqiang; Tang, Zhiyong

    2011-09-01

    Controlled synthesis of well-defined PbS nanostructures in terms of size and shape has been strongly motivated by their potential applications ranging from solar photovoltaics to near-infrared optics. Hereby, we report a facile microwave-assistant method for ultrafast fabrication of PbS nanostructures, by which uniform PbS hexapods with six arms stretching along six (100) directions of the crystal seeds have been easily synthesized within minutes. Various morphologies including rectangle plates, uniform cubes as well as nanoparticles were obtained by tuning the parameters for the formation of PbS nanocrystals. The results reveal that both concentration and feed ratio of precursors determine the growth of PbS nanocrystals significantly. And higher initial precursor concentration favors the formation of the hexapod structures. The process of crystal growth is monitored through scanning electron microscopy of PbS from different durations of the reaction. This controlled ultrafast synthesis of PbS structures at nanometer and micrometer scale with various morphologies may be promising in large scale fabrication of nanostructures. Based on the systematically study of the growth process, a possible mechanism for the formation of the hexapod-like structure is discussed.

  14. Synthesis, characterization and self-assembly of well-defined linear heptablock quaterpolymers

    KAUST Repository

    Ntaras, Christos

    2016-05-17

    Two well-defined heptablock quaterpolymers of the ABCDCBA type [Α: polystyrene (PS), B: poly(butadiene) with ∼90% 1,4-microstructure (PB1,4), C: poly(isoprene) with ∼55% 3,4-microstructure (PI3,4) and D: poly(dimethylsiloxane) (PDMS)] were synthesized by combining anionic polymerization high vacuum techniques and hydrosilylation/chlorosilane chemistry. All intermediates and final products were characterized by size exclusion chromatography, membrane osmometry, and proton nuclear magnetic resonance spectroscopy. Fourier transform infrared spectroscopy was used to further verify the chemical modification reaction of the difunctional PDMS. The self-assembly in bulk of these novel heptablock quarterpolymers, studied by transmission electron microscopy and small angle X-ray scattering, revealed 3-phase 4-layer alternating lamellae morphology of PS, PB1,4, and mixed PI3,4/PDMS domains. Differential scanning calorimetry was used to further confirm the miscibility of PI3,4 and PDMS blocks. It is the first time that PDMS is the central segment in such multiblock polymers (≥3 chemically different blocks). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1443–1449. © 2016 Wiley Periodicals, Inc.

  15. Well-Defined Dinuclear Gold Complexes for Preorganization-Induced Selective Dual Gold Catalysis

    NARCIS (Netherlands)

    Vreeken, V.; Broere, D.L.J.; Jans, A.C.H.; Lankelma, M.; Reek, J.N.H.; Siegler, M.A.; van der Vlugt, J.I.

    2016-01-01

    The synthesis, reactivity, and potential of well-defined dinuclear gold complexes as precursors for dual gold catalysis are explored. Using the preorganizing abilities of the ditopic (PNPiPr)-P-H (L-H) ligand, dinuclear Au-I-Au-I complex 1 and mixed-valent Au-I-Au-III complex 2 provide access to str

  16. Well-defined polynuclear heterobimetallic complexes as precursors for ceramic and magnetic materials.

    Science.gov (United States)

    Szafert, Sławomir; John, Lukasz; Sobota, Piotr

    2008-12-14

    Well-defined heterobi- and heteropolymetallic alkoxides are valuable precursors for numerous oxide materials with great application potential. Simple and high yield synthetic routes to such compounds are always highly desirable. This Perspective describes one of the methods that utilizes, as starting materials, homoleptic monometallic alkoxides with a free alcoholic moiety coordinated to the metal. The moiety constitutes a convenient anchor for upcoming organometallics.

  17. Well-defined temperature-sensitive surfactants for controlled emulsion coalescence

    NARCIS (Netherlands)

    Feng, Huanhuan; Verstappen, N.A.L.; Kuehne, A.J.C.; Sprakel, J.H.B.

    2013-01-01

    In a variety of applications, emulsion formulations are required, which exhibit excellent shelf stability yet can be broken or perform phase inversion at a desired time. Here we approach these contradictory constraints through the synthesis of well-defined thermoresponsive surfactants based on di(et

  18. A Well-Defined Readily Releasable Pool with Fixed Capacity for Storing Vesicles at Calyx of Held.

    Science.gov (United States)

    Mahfooz, Kashif; Singh, Mahendra; Renden, Robert; Wesseling, John F

    2016-04-01

    The readily releasable pool (RRP) of vesicles is a core concept in studies of presynaptic function. However, operating principles lack consensus definition and the utility for quantitative analysis has been questioned. Here we confirm that RRPs at calyces of Held from 14 to 21 day old mice have a fixed capacity for storing vesicles that is not modulated by Ca2+. Discrepancies with previous studies are explained by a dynamic flow-through pool, established during heavy use, containing vesicles that are released with low probability despite being immediately releasable. Quantitative analysis ruled out a posteriori explanations for the vesicles with low release probability, such as Ca2+-channel inactivation, and established unexpected boundary conditions for remaining alternatives. Vesicles in the flow-through pool could be incompletely primed, in which case the full sequence of priming steps downstream of recruitment to the RRP would have an average unitary rate of at least 9/s during heavy use. Alternatively, vesicles with low and high release probability could be recruited to distinct types of release sites; in this case the timing of recruitment would be similar at the two types, and the downstream transition from recruited to fully primed would be much faster. In either case, further analysis showed that activity accelerates the upstream step where vesicles are initially recruited to the RRP. Overall, our results show that the RRP can be well defined in the mathematical sense, and support the concept that the defining mechanism is a stable group of autonomous release sites.

  19. A Well-Defined Readily Releasable Pool with Fixed Capacity for Storing Vesicles at Calyx of Held

    Science.gov (United States)

    Mahfooz, Kashif; Singh, Mahendra; Renden, Robert; Wesseling, John F.

    2016-01-01

    The readily releasable pool (RRP) of vesicles is a core concept in studies of presynaptic function. However, operating principles lack consensus definition and the utility for quantitative analysis has been questioned. Here we confirm that RRPs at calyces of Held from 14 to 21 day old mice have a fixed capacity for storing vesicles that is not modulated by Ca2+. Discrepancies with previous studies are explained by a dynamic flow-through pool, established during heavy use, containing vesicles that are released with low probability despite being immediately releasable. Quantitative analysis ruled out a posteriori explanations for the vesicles with low release probability, such as Ca2+-channel inactivation, and established unexpected boundary conditions for remaining alternatives. Vesicles in the flow-through pool could be incompletely primed, in which case the full sequence of priming steps downstream of recruitment to the RRP would have an average unitary rate of at least 9/s during heavy use. Alternatively, vesicles with low and high release probability could be recruited to distinct types of release sites; in this case the timing of recruitment would be similar at the two types, and the downstream transition from recruited to fully primed would be much faster. In either case, further analysis showed that activity accelerates the upstream step where vesicles are initially recruited to the RRP. Overall, our results show that the RRP can be well defined in the mathematical sense, and support the concept that the defining mechanism is a stable group of autonomous release sites. PMID:27035349

  20. Comparison of diagnostic tests in distinct well-defined conditions related to dry eye disease.

    Directory of Open Access Journals (Sweden)

    Monica Alves

    Full Text Available PURPOSE: This study compares signs, symptoms and predictive tools used to diagnose dry eye disease (DED and ocular surface disorders in six systemic well-defined and non-overlapping diseases. It is well known that these tests are problematic because of a lack of agreement between them in identifying these conditions. Accordingly, we provide here a comparative clinical profile analysis of these different diseases. METHODS: A spontaneous and continuous sample of patients with Sjögren's syndrome (SS (n=27, graft-versus-host-disease (GVHD (n=28, Graves orbitopathy (n=28, facial palsy (n=8, diabetes mellitus without proliferative retinopathy (n=14 and glaucoma who chronically received topical drugs preserved with benzalkonium chloride (n=20 were enrolled. Evaluation consisted of a comprehensive protocol encompassing: (1 structured questionnaire - Ocular Surface Disease Index (OSDI; (2 tear osmolarity (TearLab Osmolarity System - Ocusense; (3 tear film break-up time (TBUT; (4 fluorescein and lissamine green staining; (5 Schirmer test and (6 severity grading. RESULTS: One hundred and twenty five patients (aged 48.8 years-old ± 14.1, male:female ratio=0.4 were enrolled in the study, along with 24 age and gender matched controls. Higher scores on DED tests were obtained in Sjögren Syndrome (P<0.05, except for tear film osmolarity that was higher in diabetics (P<0.001 and fluorescein staining, that was higher in facial palsy (P<0.001. TFBUT and OSDI correlated better with other tests. The best combination of diagnostic tests for DED was OSDI, TBUT and Schirmer test (sensitivity 100%, specificity 95% and accuracy 99.3%. CONCLUSIONS: DED diagnostic test results present a broad range of variability among different conditions. Vital stainings and TBUT correlated best with one another whereas the best test combination to detect DED was: OSDI/TBUT/Schirmer.

  1. Osteogenic response of human mesenchymal stem cells to well-defined nanoscale topography in vitro

    Directory of Open Access Journals (Sweden)

    de Peppo GM

    2014-05-01

    Full Text Available Giuseppe Maria de Peppo,1–3 Hossein Agheli,2,3 Camilla Karlsson,2,3 Karin Ekström,2,3 Helena Brisby,3,4 Maria Lennerås,2,3 Stefan Gustafsson,3,5 Peter Sjövall,3,5,6 Anna Johansson,2,3 Eva Olsson,3,5 Jukka Lausmaa,3,6 Peter Thomsen,2,3 Sarunas Petronis3,6 1The New York Stem Cell Foundation Research Institute, New York, NY, USA; 2Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, 3BIOMATCELL VINN Excellence Center of Biomaterials and Cell Therapy, 4Department of Orthopaedics, Sahlgrenska Academy, University of Gothenburg, 5Applied Physics, Chalmers University of Technology, Göteborg, Sweden; 6Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden, Borås, Sweden Background: Patterning medical devices at the nanoscale level enables the manipulation of cell behavior and tissue regeneration, with topographic features recognized as playing a significant role in the osseointegration of implantable devices. Methods: In this study, we assessed the ability of titanium-coated hemisphere-like topographic nanostructures of different sizes (approximately 50, 100, and 200 nm to influence the morphology, proliferation, and osteogenic differentiation of human mesenchymal stem cells (hMSCs. Results: We found that the proliferation and osteogenic differentiation of hMSCs was influenced by the size of the underlying structures, suggesting that size variations in topographic features at the nanoscale level, independently of chemistry, can be exploited to control hMSC behavior in a size-dependent fashion. Conclusion: Our studies demonstrate that colloidal lithography, in combination with coating technologies, can be exploited to investigate the cell response to well defined nanoscale topography and to develop next-generation surfaces that guide tissue regeneration and promote implant integration. Keywords: colloidal lithography, nanotopography, human mesenchymal stem cells, cell proliferation, osteogenic

  2. A well-defined (POCOP)Rh catalyst for the coupling of aryl halides with thiols.

    Science.gov (United States)

    Timpa, Samuel D; Pell, Christopher J; Ozerov, Oleg V

    2014-10-22

    This article describes a well-defined pincer-Rh catalyst for C-S cross-coupling reactions. (POCOP)Rh(H)(Cl) serves as an active precatalyst for the coupling of aryl chlorides and bromides with aryl and alkyl thiols under reasonable conditions (3% mol cat., 110 °C, 2-24 h, >90% yield). For select substrates, >90% yields were obtained with catalyst loading as low as 0.1%. Key mechanistic intermediates have been isolated and fully characterized, including (POCOP)Rh(Ph)(SPh) (6a) and (POCOP)Rh(SPh2) (6b). The aryl/bis(phosphinite) (POCOP)Rh system has been shown to favor aryl thiolate reductive elimination at elevated temperatures and in some cases at room temperature, compared with the analogous diarylamido/bis(phosphine) (PNP)Rh pincer system. Concerted reductive elimination has been studied with 6a directly and in the presence of aryl bromide and aryl chloride traps. This investigation demonstrates a clear rate dependence on aryl chloride concentration during catalysis, a dependence that is absent when using aryl bromides. The rate of catalysis is dramatically reduced or brought to zero for ortho-tolyl halides, which can be traced to slower C-S coupling and slower carbon-halogen oxidative addition for ortho-substituted aryls. The influence of the sterics in the thiol component is less straightforward. The S-H oxidative addition product (POCOP)Rh(H)(SPh) (16) has been fully characterized and its reactivity has been examined, resulting in the isolation of the sodium-thiolate adduct (POCOP)Rh(NaSPh) (19). The solid-state structure of 19 shows Na interactions not only with sulfur, but also with a neighboring Rh and the chelating aryl carbon of the pincer framework. The reactivity of 16 and 19 indicates that these potential side products should not hinder catalysis.

  3. Highly conductive single naphthalene and anthracene molecular junction with well-defined conductance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chenyang [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan); School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kaneko, Satoshi; Komoto, Yuki; Fujii, Shintaro, E-mail: fujii.s.af@m.titech.ac.jp; Kiguchi, Manabu, E-mail: kiguti@chem.titech.ac.jp [Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 W4-10, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2015-03-09

    We performed electronic investigation on single acene molecular junctions bridging Au-electrodes in ultra-high vacuum conditions using mechanically controllable break junction technique. While the molecular junctions displayed various conductance values at 100 K, they exhibited well-defined high conductance values (∼0.3 G{sub 0}) at 300 K, which is close to that of metal atomic contact. Direct π-binding of the molecules to the Au-electrodes leads to the high conductivities at the metal-molecule interface. At the elevated temperature, single molecular junctions trapped in local metastable structures can be fallen into energetically preferential more stable state and thus we fabricated structurally well-defined molecular junctions.

  4. Well-defined azazirconacyclopropane complexes supported on silica structurally determined by 2D NMR comparative elucidation

    KAUST Repository

    El Eter, Mohamad

    2013-01-01

    Grafting of Zr(NMe2)4 on mesoporous silica SBA-15 afforded selectively well-defined surface species SiOZr(NMe2) (η2NMeCH2). 2D solid-state NMR (1H- 13C HETCOR, Multiple Quantum) experiments have shown a unique structural rearrangement occurring on the immobilised zirconium bis methylamido ligand. © The Royal Society of Chemistry 2013.

  5. Porous hydrogels with well-defined pore structure for biomaterials applications

    Science.gov (United States)

    Marshall, Andrew J.

    When any medical device is implanted inside the body, the natural inflammatory response causes the device to be encapsulated with a thin layer of dense, relatively avascular fibrous tissue, effectively sealing off the device from the surrounding tissue and isolating it from the rest of the body. For medical devices such as electrodes and glucose sensors, where functionality depends on the ability of the device to interact with the surrounding biochemistry, the "foreign body response" poses a formidable obstacle. Previous studies have demonstrated that porous materials with pore dimensions on the order of cell dimensions can induce a modified foreign body response, resulting in more vascularized capsule tissue. However, the utility of these studies is limited because the materials used had broad pore size distributions and poorly defined pore geometries. This thesis is motivated by the unavailability of biomaterials with well-defined and controlled pore size, and by the lack of understanding of the relationships between pore dimensions and the foreign body response. Our sphere templating technology permits the fabrication of open-pore structures with precisely controlled pore dimensions. We can produce these sphere-templated pore structures out of a variety of polymeric materials, including poly(2-hydroxyethyl methacrylate) (polyHEMA), silicone rubber, and degradable copolymers of polyHEMA and poly(epsilon-caprolactone). We applied our precision-engineered pore structures in vivo to investigate the role of pore size in the foreign body response. We implanted porous polyHEMA with various pore geometries under the skin of mice and found that the level of intra-pore vascularization increases with decreasing pore size, with vascular density directly proportional to the specific surface area of the implant, and that the threshold pore throat diameter for rapid tissue in-growth is approximately 8 mum. Based on our empirical results coupled with first principles, we

  6. Well-Defined Copper(I) Fluoroalkoxide Complexes for Trifluoroethoxylation of Aryl and Heteroaryl Bromides

    KAUST Repository

    Huang, Ronglu

    2015-03-17

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Copper(I) fluoroalkoxide complexes bearing dinitrogen ligands were synthesized and the structure and reactivity of the complexes toward trifluoroethoxylation, pentafluoropropoxylation, and tetrafluoropropoxylation of aryl and heteroaryl bromides were investigated. Efficiency drive: A series of copper(I) fluoroalkoxide complexes bearing N,N ligands have been prepared and structurally characterized. These well-defined complexes serve as efficient reagents for the fluoroalkoxylation of aryl and heteroaryl bromides to produce a wide range of trifluoroethyl, pentafluoropropyl, and tetrafluoropropyl (hetero)aryl ethers in good to excellent yields.

  7. Well-defined silica-supported zirconium–imido complexes mediated heterogeneous imine metathesis

    KAUST Repository

    Hamzaoui, Bilel

    2016-02-15

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [(≡Si-O-)Zr(NEt2)3] (1) evolves into an ethylimido complex [(≡Si-O-)Zr(=NEt)NEt2] (2). Reactions of 2 with an imine substrate result in imido/imine (=NRi, R: Et, Ph) exchange (metathesis) with the formation of [(≡Si-O-)Zr(=NPh)NEt2] (3). Compounds 2 and 3 effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis. © The Royal Society of Chemistry 2016.

  8. Hollow silica capsules with well-defined asymmetric windows in the shell.

    Science.gov (United States)

    Zhao, Bo; Collinson, Maryanne M

    2012-05-15

    A straightforward and effective approach to fabricate porous silica capsules with well-defined asymmetric windows in the shell using raspberry-like templates has been developed. This process begins with the formation of a hierarchical template by chemically coupling a large polystyrene sphere to an ensemble of small, polystyrene latex spheres. The hierarchical template in conjunction with a hard templating method and spin-coating leads to silica capsules with well-defined, asymmetric pores (windows) in the outer shell. Proof-of-principle of this approach has been demonstrated using a 1500/110 nm hierarchical template. The silica capsules thus produced were characterized with scanning electron microscopy and STEM. The diameter of the capsules was ~1400 nm, and the outer opening of the windows was ~100 nm in size, consistent with the diameters of the core and satellite spheres considering the shrinkage due to the calcination. The inner opening was ~30 nm, which gives rise to an asymmetry factor, defined as the diameter of the outer window to the diameter of the inner window, of ~3. In another example, surface-bound capsules with an asymmetry factor of ~1 were made. Collectively, these windows can provide efficient pathways to connect the inside of the capsule to the outside and have potential for asymmetric diffusion and rectification.

  9. Long-term changes in bone mass after partial gastrectomy in a well-defined population and its relation to tobacco and alcohol consumption

    DEFF Research Database (Denmark)

    Krogsgaard, M R; Frølich, A; Lund, B;

    1995-01-01

    We studied the long-term effect of partial gastrectomy on bone metabolism in a well defined population of gastrectomized patients compared to an age- and sex-matched group with unoperated peptic ulcers (controls). We selected 61 individuals between 61 and 70 years old at the time of investigation...... and insignificantly lower in the other operated groups. In men, ionized and total calcium was reduced, and 24-hour excretion of hydroxyproline in the urine as increased (p ... and unoperated patients in serum levels of alkaline phosphatases, iPTH, calcitriol, or the 24-hour urine calcium/creatinine excretion, even though there was a trend toward lower 24-hour urine calcium/creatinine ratio and increased levels in iPTH in the operated groups. There was no correlation between the daily...

  10. Well-Defined Bilayered Molecular Cobrushes with Internal Polyethylene Blocks and ω-Hydroxyl-Functionalized Polyethylene Homobrushes

    KAUST Repository

    Zhang, Hefeng

    2016-02-15

    Novel well-defined bilayered molecular cobrushes with internal polyethylene blocks, P(PEcore-b-PScorona) (PE: polyethylene; PS: polystyrene), and ω-hydroxyl-functionalized polyethylene homobrushes, P(PE-OH), were synthesized through the macromonomer strategy. Two main steps were involved in the synthesis of the P(PEcore-b-PScorona) bilayered cobrushes: (i) formation of norbornyl-terminated macromonomer (Nor-PE-b-PS) by esterification of PS-b-PE-OH (combination of anionic polymerization, hydroboration, and polyhomologation) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis polymerization (ROMP) of Nor-PE-b-PS. The synthesis of P(PE-OH) was achieved by (i) hydroboration of tert-butyldimethylsilyl-protected allyl alcohol, followed by polyhomologation of dimethylsulfoxoniun methylide with the formed tri[3-(tert-butyldimethylsilyloxyl)propyl]borane initiator, oxidation/hydrolysis, and esterification of the TBDMS-O-PE-OH with 5-norbornene-2-carboxylic acid to afford the macromonomer TBDMS-O-PE-Nor, and (ii) ROMP of TBDMS-O-PE-Nor, followed by deprotection. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) and high temperature gel permeation chromatography (HT-GPC) were used to characterize all macromonomers/molecular brushes and differential scanning calorimetry (DSC) to study the thermal properties. The molecular brush P(PE-b-PS) showed lower melting point (Tm) and better solubility in toluene than the corresponding macromonomer PS-b-PE-Nor. In the case of homobrushes, the thermal properties were strongly affected by the presence of the PE end-groups. © 2016 American Chemical Society.

  11. Formation and stability of small well-defined Cu- and Ni oxide particles

    Energy Technology Data Exchange (ETDEWEB)

    Thalinger, Ramona [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Heggen, Marc; Stroppa, Daniel G. [Ernst Ruska Zentrum und Peter Grünberg Institut, Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Stöger-Pollach, Michael [University Service Facility for Transmission Electron Microscopy (USTEM), Vienna University of Technology, A-1040 Vienna (Austria); Klötzer, Bernhard [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria); Penner, Simon, E-mail: simon.penner@uibk.ac.at [Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck (Austria)

    2013-12-16

    Well-defined and -structured Cu/Cu{sub 2}O and Ni/NiO composite nanoparticles have been prepared by physical-vapor deposition on vacuum-cleaved NaCl(001) single crystal facets. Epitaxial growth has been observed due to the close crystallographic matching of the respective cubic crystal lattices. Distinct particle morphologies have only been obtained for the Ni/NiO particles, comprising truncated half-octahedral, rhombohedral- and pentagonal-shaped outlines. Oxidation of the particles in the temperature range 473–673 K in both cases led to the formation of well-defined CuO and NiO particles with distinct morphologies. Whereas CuO possibly adopts its thermodynamical equilibrium shape, NiO formation is accompanied by entering a Kirkendall-like state, that is, a hollow core–shell structure is obtained. The difference in the formation of the oxides is also reflected by their stability under reducing conditions. CuO transforms back to a polycrystalline mixture of Cu metal, Cu{sub 2}O and CuO after reduction in hydrogen at 673 K. In contrast, as expected from theoretical stability considerations, the formation of the hollow NiO structure is reversed upon annealing in hydrogen at 673 K and moreover results in the formation of a Ni-rich silicide structure Ni{sub 3}Si{sub 2}. The discussed systems present a convenient way to tackle and investigate various problems in nanotechnology or catalysis, including phase transformations, establishing structure/activity relationships or monitoring intermetallic particles, starting from well-defined and simple models. - Highlights: • Preparation of epitaxial Cu/Cu{sub 2}O and Ni/NiO composite nanoparticles on NaCl(001). • Distinct Ni/NiO particle morphologies. • Formation of well-shaped CuO and NiO particles upon oxidation. • Reversal of Kirkendall-NiO-state upon reduction/annealing in hydrogen.

  12. Hydrolases Part I: Enzyme Mechanism, Selectivity and Control in the Synthesis of Well-Defined Polymers

    Science.gov (United States)

    Veld, Martijn A. J.; Palmans, Anja R. A.

    Lipases are highly activity in the polymerization of a range of monomers. Both ring-opening polymerization of cyclic esters and polycondensation reactions of AA-BB and AB monomers have been investigated in great detail. This paper reviews the increased understanding in enzymatic strategies for the production of well-defined polymers. Major advantages of enzymatic catalysts are the relatively mild reaction conditions, and the often-observed excellent regio-, chemo-, and enantioselectivity that allow for the direct preparation of functional materials. However, as a result of the monomer activation mechanism, polymers of low polydispersity and low quantitative degree of endgroup functionality are difficult to attain. A wide variety of (co)polymers have been synthesized and explored in a variety of applications using lipase catalysts.

  13. Well-defined, nanometer-sized LiH cluster compounds stabilized by pyrazolate ligands.

    Science.gov (United States)

    Stasch, Andreas

    2014-01-27

    The assembly of well-defined large cluster compounds of ionic light metal hydrides is a synthetic challenge and of importance for synthesis, catalysis, and hydrogen storage. The synthesis and characterization of a series of neutral and anionic pyrazolate-stabilized lithium hydride clusters with inorganic cores in the nanometer region is now reported. These complexes were prepared in a bottom-up approach using alkyl lithium and lithium pyrazolate mixtures with silanes in hydrocarbon solutions. Structural characterization using synchrotron radiation revealed isolated cubic clusters that contain up to 37 Li(+) cations and 26 H(-) ions. Substituted pyrazolate ligands were found to occupy all corners and some edges for the anionic positions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Well-defined silica-supported zirconium-imido complexes mediated heterogeneous imine metathesis.

    Science.gov (United States)

    Hamzaoui, Bilel; Pelletier, Jérémie D A; Abou-Hamad, Edy; Basset, Jean-Marie

    2016-03-28

    Upon prolonged thermal exposure under vacuum, a well-defined single-site surface species [([triple bond, length as m-dash]Si-O-)Zr(NEt2)3] () evolves into an ethylimido complex [([triple bond, length as m-dash]Si-O-)Zr([double bond, length as m-dash]NEt)NEt2] (). Reactions of with an imine substrate result in imido/imine ([double bond, length as m-dash]NRi, R: Et, Ph) exchange (metathesis) with the formation of [([triple bond, length as m-dash]Si-O-)Zr([double bond, length as m-dash]NPh)NEt2] (). Compounds and effectively catalyze imine/imine cross-metathesis and are thus considered as the first heterogeneous catalysts active for imine metathesis.

  15. Bottom-Up Engineering of Well-Defined 3D Microtissues Using Microplatforms and Biomedical Applications.

    Science.gov (United States)

    Lee, Geon Hui; Lee, Jae Seo; Wang, Xiaohong; Lee, Sang Hoon

    2016-01-07

    During the last decades, the engineering of well-defined 3D tissues has attracted great attention because it provides in vivo mimicking environment and can be a building block for the engineering of bioartificial organs. In this Review, diverse engineering methods of 3D tissues using microscale devices are introduced. Recent progress of microtechnologies has enabled the development of microplatforms for bottom-up assembly of diverse shaped 3D tissues consisting of various cells. Micro hanging-drop plates, microfluidic chips, and arrayed microwells are the typical examples. The encapsulation of cells in hydrogel microspheres and microfibers allows the engineering of 3D microtissues with diverse shapes. Applications of 3D microtissues in biomedical fields are described, and the future direction of microplatform-based engineering of 3D micro-tissues is discussed.

  16. Study Groups in Denmark

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    2007-01-01

    Since 1998 European Study Groups have been held in Denmark, and Danish companies from LEGO and NOVO to very small high-tech firms have participated. I briefly describe the history, the organisation and the format of the Danish Study Groups, and highlight a few problem solutions....

  17. Production and deposition of well defined aerosol nanoparticles for studies of basic properties

    NARCIS (Netherlands)

    Peineke, C.

    2008-01-01

    The search for new materials and material properties has advanced to smaller and smaller structures during the past years. Inorganic particles in the size range below {100 nm} are interesting for many applications, because on this scale properties often vary strongly from bulk. Nanoparticles are t

  18. Well-Defined Silica Supported Aluminum Hydride: Another Step Towards the Utopian Single Site Dream?

    KAUST Repository

    Werghi, Baraa

    2015-07-17

    Reaction of triisobutylaluminum with SBA15700 at room temperature occurs by two parallel pathways involving either silanol or siloxane bridges. It leads to the formation of a well-defined bipodal [(≡SiO)2Al-CH2CH(CH3)2] 1a, silicon isobutyl [≡Si-CH2CH(CH3)2] 1b and a silicon hydride [≡Si-H] 1c. Their structural identity was characterized by FT-IR and advance solid-state NMR spectroscopies (1H, 13C, 29Si, 27Al and 2D multiple quantum), elemental and gas phase analysis, and DFT calculations. The reaction involves the formation of a highly reactive monopodal intermediate: [≡SiO-Al-[CH2CH(CH3)2]2], with evolution of isobutane. This intermediate undergoes two parallel routes: Transfer of either one isobutyl fragment or of one hydride to an adjacent silicon atom. Both processes occur by opening of a strained siloxane bridge, ≡Si-O-Si≡ but with two different mechanisms, showing that the reality of “single site” catalyst may be an utopia: DFT calculations indicate that isobutyl transfer occurs via a simple metathesis between the Al-isobutyl and O-Si bonds, while hydride transfer occurs via a two steps mechanism, the first one is a ß-H elimination to Al with elimination of isobutene, whereas the second is a metathesis step between the formed Al-H bond and a O-Si bond. Thermal treatment of 1a (at 250 °C) under high vacuum (10-5 mbar) generates Al-H through a ß-H elimination of isobutyl fragment. These supported well-defined Al-H which are highly stable with time, are tetra, penta and octa coordinated as demonstrated by IR and 27Al–1H J-HMQC NMR spectroscopy. All these observations indicate that surfaces atoms around the site of grafting play a considerable role in the reactivity of a single site system.

  19. Group theories: relevance to group safety studies.

    Science.gov (United States)

    Benevento, A L

    1998-01-01

    Promoting safety in the workplace has been attempted in a variety of ways. Increasingly, industries are using groups such as safety teams and quality circles to promote worker safety. Group influences on individual behavior and attitudes have long been studied in the social psychology literature, but the theories have not been commonly found outside the psychology arena. This paper describes the group theories of group polarization, risky shift, social loafing, groupthink and team think and attempts to apply these theories to existing studies that examine work group influences on safety. Interesting parallels were found but only one study examined group influences as their primary focus of research. Since groups are increasingly used for safety promotion, future research on safety that studies group influences with respect to current group theories is recommended.

  20. Acyclic Diene Metathesis (ADMET Polymerization for Precise Synthesis of Defect-Free Conjugated Polymers with Well-Defined Chain Ends

    Directory of Open Access Journals (Sweden)

    Tahmina Haque

    2015-03-01

    Full Text Available This accounts introduces unique characteristics by adopting the acyclic diene metathesis (ADMET polymerization for synthesis of conjugated polymers, poly(arylene vinylenes, known as promising molecular electronics. The method is more suitable than the other methods in terms of atom efficiency affording defect-free, stereo-regular (exclusive trans polymers with well-defined chain ends; the resultant polymers possess better property than those prepared by the conventional methods. The chain ends (vinyl group in the resultant polymer prepared by ruthenium-carbene catalyst(s can be modified by treating with molybdenum-alkylidene complex (olefin metathesis followed by addition of various aldehyde (Wittig type cleavage, affording the end-functionalized polymers exclusively. An introduction of initiating fragment, the other conjugated segment, and one-pot synthesis of end-functionalized block copolymers, star shape polymers can be achieved by adopting this methodology.

  1. Measurement and calculation of fast neutron and gamma spectra in well defined cores in LR-0 reactor.

    Science.gov (United States)

    Košťál, Michal; Matěj, Zdeněk; Cvachovec, František; Rypar, Vojtěch; Losa, Evžen; Rejchrt, Jiří; Mravec, Filip; Veškrna, Martin

    2017-02-01

    A well-defined neutron spectrum is essential for many types of experimental topics and is also important for both calibration and testing of spectrometric and dosimetric detectors. Provided it is well described, such a spectrum can also be employed as a reference neutron field that is suitable for validating selected cross sections. The present paper aims to compare calculations and measurements of such a well-defined spectra in geometrically similar cores of the LR-0 reactor with fuel containing slightly different enrichments (2%, 3.3% and 3.6%). The common feature to all cores is a centrally located dry channel which can be used for the insertion of studied materials. The calculation of neutron and gamma spectra was realized with the MCNP6 code using ENDF/B-VII.0, JEFF-3.1, JENDL-3.3, ROSFOND-2010 and CENDL-3.1 nuclear data libraries. Only minor differences in neutron and gamma spectra were found in the comparison of the presented reactor cores with different fuel enrichments. One exception is the gamma spectrum in the higher energy region (above 8MeV), where more pronounced variations could be observed.

  2. In Situ SIMS and IR Spectroscopy of Well-Defined Surfaces Prepared by Soft Landing of Mass-Selected Ions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Gunaratne, Kalupathirannehelage Don D.; Laskin, Julia

    2014-06-16

    Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+, onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

  3. Well-Defined Polyethylene-Based Random, Block, and Bilayered Molecular Cobrushes

    KAUST Repository

    Zhang, Hefeng

    2015-06-09

    Novel well-defined polyethylene-based random, block, and bilayered molecular cobrushes were synthesized through the macromonomer strategy. Two steps were involved in this approach: (i) synthesis of norbornyl-terminated macromonomers of polyethylene (PE), polycaprolactone (PCL), poly(ethylene oxide) (PEO), and polystyrene (PS), as well as polyethylene-b-polycaprolactone (PE-b-PCL), by esterification of the hydroxyl-terminated precursors (PE, PCL, PEO, PS, and PE-b-PCL) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis (co)polymerization of the resulting macromonomers to afford the PE-based molecular cobrushes. The PE-macromonomers were synthesized by polyhomologation of dimethylsulfoxonium methylide, while the others by anionic polymerization. Proton nuclear magnetic resonance spectroscopy (1H NMR) and high-temperature gel permeation chromatography (HT-GPC) were used to imprint the molecular characteristics of all macromonomers and molecular brushes and differential scanning calorimetry (DSC) for the thermal properties. The bilayered molecular cobrushes of P(PE-b-PCL) adopt a wormlike morphology on silica wafer as visualized by atomic force microscopy (AFM). © 2015 American Chemical Society.

  4. Inactivation of enzymes by organic solvents: New technique with well-defined interfacial area

    Energy Technology Data Exchange (ETDEWEB)

    Ghatorae, A.S.; Bell, G.; Halling, P.J. (Univ. of Strathclyde, Glasgow (United Kingdom))

    1994-02-20

    A liquid-liquid bubble column apparatus allows exposure of enzyme solutions to water-immiscible organic solvents with a known total interfacial area and well-defined time scales and flow. It allows clear distinction of the different classes of inactivation mechanism. With urease as a model enzyme, octan-2-one and butylbenzene act only through the effects of solvent molecules dissolved in the aqueous phase, giving first-order inactivation at 0.34 and 0.21 h[sup [minus]1], respectively. Hexane and tridecane act only through exposure to the interface. The amount of urease inactivated is proportional to the total area of interface exposed, rather than to elapsed time, and may be characterized by a rate of about 0.5 [mu]kat m[sup [minus]2]. This is consistent with the formation and inactivation of a complete adsorbed monolayer of protein. With butan-1-ol, both mechanisms contribute significantly to the observed inactivation. The presence of O[sub 2] increases the rate of interfacial inactivation, but not that by dissolved solvent.

  5. The deficit is not a well-defined measure of fiscal policy.

    Science.gov (United States)

    Kotlikoff, L J

    1988-08-12

    Notwithstanding its widespread use, the government's deficit is not a well-defined measure of fiscal policy from the perspective of neoclassical economics; the equations of neoclassical models do not define the deficit. Rather than being a fundamental economic concept, the deficit is an arbitrary cash flow accounting construct with no necessary relation to the true stance of fiscal policy. Although the deficit is supposed to indicate how the burden of paying for the government's consumption is spread across different generations, actual changes in the measured deficit in the United States have had little if any relation to changes in the burden imposed by the government on different generations. The deficit's lack of definition is illustrated with a simple model, and the potential for misreading fiscal policy is discussed with U.S. fiscal policy in the 1980s as an example. In this article, creation of present value generational accounts are called for that would properly measure the intergenerational stance of fiscal policy.

  6. Synthesis and Complexation of Well-Defined Labeled Poly(N,N-dimethylaminoethyl methacrylates (PDMAEMA

    Directory of Open Access Journals (Sweden)

    Mark Billing

    2015-11-01

    Full Text Available We present the synthesis and characterization of well-defined polycationic copolymers containing thiazole dyes in the side chain. Atom transfer radical polymerization (ATRP was used for the copolymerization of 3-azidopropyl methacrylate (AzPMA and N,N-dimethylaminoethyl methacrylate (DMAEMA of different composition. Thiazole-based alkyne-functionalized dyes (e.g., 5-methyl-4-(prop-2-yn-1-yloxy-2-(pyridin-2-ylthiazole, (MPPT were afterwards covalently attached using copper catalyzed azide alkyne cycloadditions (CuAAC reaching contents of up to 9 mol % dye. Subsequent quaternization of the tertiary nitrogen of DMAEMA with strong methylation agents (e.g., methyl iodide led to permanently charged polyelectrolytes. The materials were characterized by size exclusion chromatography, as well as NMR- and UV/VIS-spectroscopy. Particular attention is paid to the spectroscopic properties of the dyes in the side chain upon environmental changes such as pH and salinity. We anticipate the application of such precisely functionalized polyelectrolytes as temperature- and pH-responsive sensors in biomedical applications, e.g., within interpolyelectrolyte complexes. Concerning the latter, first complex formation results are demonstrated.

  7. Measurement of (23)Na(n,2n) cross section in well-defined reactor spectra.

    Science.gov (United States)

    Košťál, Michal; Švadlenková, Marie; Baroň, Petr; Milčák, Ján; Mareček, Martin; Uhlíř, Jan

    2016-05-01

    The present paper aims to compare the calculated and experimental reaction rates of (23)Na(n,2n)(22)Na in a well-defined reactor spectra of a special core assembled in the LR-0 reactor. The experimentally determined reaction rate, derived using gamma spectroscopy of irradiated NaF sample, is used for average cross section determination. The resulting value averaged in spectra is 0.91±0.02µb. This cross-section is important as it is included in International Reactor Dosimetry and Fusion File and is also relevant to the correct estimation of long-term activity of Na coolant in Sodium Fast Reactors. The calculations were performed with the MCNP6 code using ENDF/B-VII.0, JEFF-3.1, JEFF-3.2, JENDL-3.3, JENDL-4, ROSFOND-2010 and CENDL-3.1 nuclear data libraries. Generally the best C/E agreement, within 2%, was found using the ROSFOND-2010 data set, whereas the worst, as high as 40%, was found using the ENDF/B-VII.0.

  8. A one-step co-condensation method for the synthesis of well-defined functionalized mesoporous SBA-15 using trimethallylsilanes as organosilane sources.

    Science.gov (United States)

    Han, Ye Ri; Park, Jung-Woo; Kim, Hanil; Ji, Hyejeong; Lim, Soo Hyun; Jun, Chul-Ho

    2015-12-14

    A new method for the preparation of well-defined functionalized mesoporous SBA-15 has been developed by a one-step co-condensation method using trimethallylsilanes as organosilane sources. This new method enables the incorporation of various bulky organic functional groups with long alkyl chain tethers into the mesoporous silica network.

  9. Well-defined cholesterol polymers with pH-controlled membrane switching activity.

    Science.gov (United States)

    Sevimli, Sema; Inci, Fatih; Zareie, Hadi M; Bulmus, Volga

    2012-10-08

    Cholesterol has been used as an effective component of therapeutic delivery systems because of its ability to cross cellular membranes. Considering this, well-defined copolymers of methacrylic acid and cholesteryl methacrylate, poly(methacrylic acid-co-cholesteryl methacrylate) P(MAA-co-CMA), were generated as potential delivery system components for pH-controlled intracellular delivery of therapeutics. Statistical copolymers with varying cholesterol contents (2, 4, and 8 mol %) were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Dynamic light scattering (DLS) analysis showed that the hydrodynamic diameters of the copolymers in aqueous solutions ranged from 5 ± 0.3 to 7 ± 0.4 nm for the copolymers having 2 and 4 mol % CMA and 8 ± 1.1 to 13 ± 1.9 nm for the copolymer having 8 mol % CMA with increasing pH (pH 4.5-7.4). Atomic force microscopy (AFM) analysis revealed that the copolymer having 8 mol % CMA formed supramolecular assemblies while the copolymers having 2 and 4 mol % CMA existed as unimers in aqueous solution. The pH-responsive behavior of the copolymers was investigated via UV-visible spectroscopy revealing phase transitions at pH 3.9 for 2 mol % CMA, pH 4.7 for 4 mol % CMA, and pH 5.4 for 8 mol % CMA. Lipid bilayers and liposomes as models for cellular membranes were generated to probe their interactions with the synthesized copolymers. The interactions were determined in a pH-dependent manner (at pH 5.0 and 7.4) using surface plasmon resonance (SPR) spectroscopy and liposome leakage assay. Both the SPR analyses and liposome leakage assays indicated that the copolymer containing 2 mol % CMA displayed the greatest polymer-lipid interactions at pH 5.0, presenting the highest binding ability to the lipid bilayer surfaces, and also demonstrating the highest membrane destabilization activity. CellTiter-Blue assay showed that the copolymers did not affect the cell viability up to 30 μM over a period of 72 h.

  10. Fulleretic Well-Defined Scaffolds: Donor-Fullerene Alignment Through Metal Coordination and Its Effect on Photophysics.

    Science.gov (United States)

    Williams, Derek E; Dolgopolova, Ekaterina A; Godfrey, Danielle C; Ermolaeva, Evgeniya D; Pellechia, Perry J; Greytak, Andrew B; Smith, Mark D; Avdoshenko, Stanislav M; Popov, Alexey A; Shustova, Natalia B

    2016-07-25

    Herein, we report the first example of a crystalline metal-donor-fullerene framework, in which control of the donor-fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The (13) C cross-polarization magic-angle spinning NMR spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy-transfer (ET) studies of the fulleretic donor-acceptor scaffold. Furthermore, in combination with photoluminescence measurements, the theoretical calculations of the spectral overlap function, Förster radius, excitation energies, and band structure were employed to elucidate the photophysical and ET processes in the prepared fulleretic material. We envision that the well-defined fulleretic donor-acceptor materials could contribute not only to the basic science of fullerene chemistry but would also be used towards effective development of organic photovoltaics and molecular electronics.

  11. Design and synthesis of structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization chemistry

    Institute of Scientific and Technical Information of China (English)

    Dong Jinyong

    2006-01-01

    Functionalization of polyolefins is an industrially important yet scientifically challenging research subject.This paper summarizes our recent effort to access structurally well-defined functional polypropylenes via transition metal-mediated olefin polymerization.In one approach,polypropylenes containing side chain functional groups of controlled concentrations were obtained by Ziegler-Natta-catalyzed copolymerization of propylene in combination with either living anionic or controlled radical polymerization of polar monomers.The copolymerization of propylene with 1,4-divinylbenzene using an isospecific MgC12-supported TIC14 catalyst yielded potypropylenes containing pendant styrene moieties.Both metalation reaction with n-butyllithium and hydrochlorination reaction with dry hydrogen chloride selectively and quantitatively occurred at the pendant reactive sites,generating polymeric benzyllithium and 1-chloroethylbenzene species.These species initiated living anionic polymerization of styrene(S)and atom transfer radical polymerization(in the presence of CuC1 and pentamethyldiethylenetriamine) of methyl methacrylate(MMA),respectively,resulting in functional polypropylene graft copolymers(PP-g-PS and PP-g-PMMA)with controllable graft lengths.In another approach,chain end-functionalized polypropylenes containing a terminal OH-group with controlled molecular weights were directly prepared by propylene polymerization with a metaUocene catalyst through a selective aluminum chain transfer reaction.Both approaches proved to be desirable polyolefin functionalization routes in terms of efficiency and polymer structure controllability.

  12. SYNTHESIS AND CHARACTERIZATION OF STRUCTURALLY WELL-DEFINED POLYMER-INORGANIC HYBRID NANOPARTICLES VIA ATRP

    Institute of Scientific and Technical Information of China (English)

    Jie Bai; Jie-bin Pang; Kun-yuan Qiu; Yen Wei

    2002-01-01

    Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles. 2-(4-Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this "grafting from" reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.

  13. Well-defined triblock copolymers of polyethylene with polycaprolactone or polystyrene using a novel difunctional polyhomologation initiator

    KAUST Repository

    Hadjichristidis, Nikolaos

    2017-08-04

    α,ω-Dihydroxy polyethylene was synthesized by polyhomologation of dimethylsulfoxonium methylide with 9-thexyl-9-BBN (9-BNN: 9-Borabicyclo[3.3.1]nonane), a novel difunctional initiator produced from 9-BBN and 2,3-dimethylbut-2-ene, with two active and one blocked sites, followed by hydrolysis/oxidation. The terminal hydroxy groups were either used directly as initiators, in the presence of 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ5,4λ5-catenadi(phosphazene) (t-BuP2), for the ring opening polymerization of ɛ-caprolactone to afford polycaprolactone-b-polyethylene-b-polycaprolactone (PCL-b-PE-b-PCL) or after transformation to atom transfer radical polymerization initiating sites, for the polymerization of styrene to produce polystyrene-b-polyethylene-b-polystyrene (PSt-b-PE-b-PSt) triblock copolymers. Molecular characterization by 11B, 13C and 1H NMR as well as FTIR, and high temperature GPC (HT-GPC) confirmed the well-defined nature of the synthesized new difunctional initiator and triblock copolymers. Differential scanning calorimetry was used to determine the melting points of PE and PCL.

  14. Enzymatically fabricated and degradable microcapsules for production of multicellular spheroids with well-defined diameters of less than 150 microm.

    Science.gov (United States)

    Sakai, Shinji; Ito, Sho; Ogushi, Yuko; Hashimoto, Ichiro; Hosoda, Natsuko; Sawae, Yoshinori; Kawakami, Koei

    2009-10-01

    Microcapsules with a single, spherical hollow core less than 150 microm in diameter were developed to obtain multicellular spheroids with well-defined sizes of less than 150 microm in diameter. An aqueous solution of phenolic hydroxyl derivative of carboxymethylcellulose (CMC-Ph) containing human hepatoma cell line (HepG2) cells and horse radish peroxidase (HRP) was injected into a coflowing stream of liquid paraffin, containing H(2)O(2), resulting in cell-enclosing CMC-Ph microparticles, 135 microm in diameter, via a peroxidase-catalyzed crosslinking reaction. The CMC-Ph microparticles were then coated with a phenolic hydroxyl derivative of alginate (Alg-Ph) gel membrane several dozen micrometers in thickness, crosslinked via the same enzymatic reaction process, followed by further crosslinking between the carboxyl groups of alginate by Sr(2+). A hollow core structure was achieved by immersing the resultant microcapsules in a medium containing cellulase, which degrades the enclosed CMC-Ph microparticles. The HepG2 cells in the microcapsules then grew and completely filled the hollow core. Multicellular spheroids the same size as the CMC-Ph microparticles, with living cells at their outer surface, were collected within 1 min by soaking them in a medium containing alginate lyase to degrade the Alg-Ph gel microcapsule membrane.

  15. Functional limitations in functional somatic syndromes and well-defined medical diseases : Results from the general population cohort LifeLines

    NARCIS (Netherlands)

    Joustra, Monica L.; Janssens, Karin A.M.; Bültmann, Ute; Rosmalen, Judith G.M.

    Objective: Functional somatic syndromes (FSS), defined as physical syndromes without known underlying organic pathology, are sometimes regarded as less serious conditions than well-defined medical diseases (MD). The aims of this study were to evaluate functional limitations in FSS, and to compare

  16. Synthesis of well-defined functional PE graft copolymers via ATRP process

    Institute of Scientific and Technical Information of China (English)

    CAO Chengang; DONG Jinyong; HU Youliang

    2005-01-01

    @@ Polyethylene (PE) is one of the most important polymeric materials. It has excellent physical mechanical properties and thus a widespread range of applications. However, due to the lack of polar functional groups on its polymer chain, PE usually suffers from poor adhesion to and incompatibility with other polymers or materials, which has significantly limited many of its end uses. To resolve this problem, one of the established approaches is to introduce a second functional polymeric component as side chains to synthesize PE graft copolymers that not only provide a large quantity of functional groups to impart polarity to PE but also preserve the original desired PE properties, such as crystallinity, melting point, and hydrophobicity[1].

  17. Well-defined nanostructured surface-imprinted polymers for highly selective magnetic separation of fluoroquinolones in human urine.

    Science.gov (United States)

    He, Yonghuan; Huang, Yanyan; Jin, Yulong; Liu, Xiangjun; Liu, Guoquan; Zhao, Rui

    2014-06-25

    The construction of molecularly imprinted polymers on magnetic nanoparticles gives access to smart materials with dual functions of target recognition and magnetic separation. In this study, the superparamagnetic surface-molecularly imprinted nanoparticles were prepared via surface-initiated reversible addition-fragmentation chain transfer (RAFT) polymerization using ofloxacin (OFX) as template for the separation of fluoroquinolones (FQs). Benefiting from the living/controlled nature of RAFT reaction, distinct core-shell structure was successfully constructed. The highly uniform nanoscale MIP layer was homogeneously grafted on the surface of RAFT agent TTCA modified Fe3O4@SiO2 nanoparticles, which favors the fast mass transfer and rapid binding kinetics. The target binding assays demonstrate the desirable adsorption capacity and imprinting efficiency of Fe3O4@MIP. High selectivity of Fe3O4@MIP toward FQs (ofloxacin, pefloxacin, enrofloxacin, norfloxacin, and gatifloxacin) was exhibited by competitive binding assay. The Fe3O4@MIP nanoparticles were successfully applied for the direct enrichment of five FQs from human urine. The spiked human urine samples were determined and the recoveries ranging from 83.1 to 103.1% were obtained with RSD of 0.8-8.2% (n = 3). This work provides a versatile approach for the fabrication of well-defined MIP on nanomaterials for the analysis of complicated biosystems.

  18. Triplet formation involving a polar transition state in a well-defined intramolecular perylenediimide dimeric aggregate

    NARCIS (Netherlands)

    D. Veldman; S.M.A. Chopin; S.C.J. Meskers; M.M. Groeneveld; R.M. Williams; R.A.J. Janssen

    2008-01-01

    A cofacially stacked perylenediimide (PDI) dimer with a xanthene linker was studied under a variety of conditions (solvent, temperature) and serves as a model for the molecular interactions occurring in solid films. Intrinsically, the PDI units have a fluorescence quantum yield (Phi(F)) close to uni

  19. CO2 Electroreduction on Well-Defined Bimetallic Surfaces

    DEFF Research Database (Denmark)

    Varela Gasque, Ana Sofia; Schlaup, Christian Georg; Jovanov, Zarko P.

    2013-01-01

    We have studied the electrochemical reduction of CO2 on Cu overlayers on Pt(111) and Pt(211) surfaces. These systems were chosen to investigate the effect of strain on the catalytic activity of Cu surfaces and to obtain information about the role of steps in this process. The selectivity toward h...

  20. Organometallic synthesis, reactivity and catalysis in the solid state using well-defined single-site species

    OpenAIRE

    Pike, Sebastian D.; Weller, Andrew S.

    2015-01-01

    Acting as a bridge between the heterogeneous and homogeneous realms, the use of discrete, well-defined, solid-state organometallic complexes for synthesis and catalysis is a remarkably undeveloped field. Here, we present a review of this topic, focusing on describing the key transformations that can be observed at a transition-metal centre, as well as the use of well-defined organometallic complexes in the solid state as catalysts. There is a particular focus upon gas–solid reactivity/catalys...

  1. Excited state electron transfer in systems with a well-defined geometry. [cyclophane

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, K.J.

    1980-12-01

    The effect of temperature, dielectric strength and ligand on the structure of the mesopyropheophorbide cyclophanes will be studied. ESR, NMR, emission and absorption spectroscopy, as well as circular dichroism will be used. The changes in structure will be correlated with changes in the photochemical activity. Electron acceptors such as benzoquinone will be utilized to stabilize the charge separation. Charge separation in porphyrin quinone dimers will also be studied. It was found that electron transfer in the cyclophane system is relatively slow. This is presumably due to an orientation requirement for fast electron transfer. Solvent dielectric also is important in producing a charge separation. Decreasing the temperature effects the yield of charge transfer, but not the kinetics.

  2. Well-defined single-site monohydride silica-supported zirconium from azazirconacyclopropane

    KAUST Repository

    Hamzaoui, Bilel

    2015-01-13

    The silica-supported azazirconacyclopropane ≡SiOZr(HNMe2)(η2-NMeCH2)(NMe2) (1) leads exclusively under hydrogenolysis conditions (H2, 150°C) to the single-site monopodal monohydride silica-supported zirconium species ≡SiOZr(HNMe2)(NMe2)2H (2). Reactivity studies by contacting compound 2 with ethylene, hydrogen/ethylene, propene, or hydrogen/propene, at a temperature of 200°C revealed alkene hydrogenation.

  3. Electronic Structure and Reactivity of a Well-Defined Mononuclear Complex of Ti(II).

    Science.gov (United States)

    Wijeratne, Gayan B; Zolnhofer, Eva M; Fortier, Skye; Grant, Lauren N; Carroll, Patrick J; Chen, Chun-Hsing; Meyer, Karsten; Krzystek, J; Ozarowski, Andrew; Jackson, Timothy A; Mindiola, Daniel J; Telser, Joshua

    2015-11-02

    A facile and high-yielding protocol to the known Ti(II) complex trans-[(py)4TiCl2] (py = pyridine) has been developed. Its electronic structure has been probed experimentally using magnetic susceptibility, magnetic circular dichroism, and high-frequency and high-field electron paramagnetic resonance spectroscopies in conjunction with ligand-field theory and computational methods (density functional theory and ab initio methods). These studies demonstrated that trans-[(py)4TiCl2] has a (3)Eg ground state (dxy(1)dxz,yz(1) orbital occupancy), which, as a result of spin–orbit coupling, yields a ground-state spinor doublet that is EPR active, a first excited-state doublet at ∼60 cm(–1), and two next excited states at ∼120 cm(–1). Reactivity studies with various unsaturated substrates are also presented in this study, which show that the Ti(II) center allows oxidative addition likely via formation of [Ti(η(2)-R2E2)Cl2(py)n] E = C, N intermediates. A new Ti(IV) compound, mer-[(py)3(η(2)-Ph2C2)TiCl2], was prepared by reaction with Ph2C2, along with the previously reported complex trans-(py)3Ti═NPh(Cl)2, from reaction with Ph2N2. Reaction with Ph2CN2 also yielded a new dinuclear Ti(IV) complex, [(py)2(Cl)2Ti(μ2:η(2)-N2CPh2)2Ti(Cl)2], in which the two Ti(IV) ions are inequivalently coordinated. Reaction with cyclooctatetraene (COT) yielded a new Ti(III) complex, [(py)2Ti(η(8)-COT)Cl], which is a rare example of a mononuclear “piano-stool” titanium complex. The complex trans-[(py)4TiCl2] has thus been shown to be synthetically accessible, have an interesting electronic structure, and be reactive toward oxidation chemistry.

  4. Cladding layer on well-defined double-wall TiO2 nanotubes.

    Science.gov (United States)

    Xue, Chaorui; Yonezawa, Tetsu; Nguyen, Mai Thanh; Lu, Xu

    2015-02-03

    Highly ordered double-wall TiO2 nanotube arrays were obtained by a two-step anodization method in a fluoride-containing glycerol based electrolyte. The low water and fluoride content and high viscosity of the electrolyte support a partly undissolved fluoride-rich layer, and its hydrolyzed products remain on the tube walls. The double-wall structure and a cladding layer originating from the fluoride-rich layer were clearly observed after annealing. The morphology and crystal structure of the cladding layer were investigated. The study of the cladding layer gives a fundamental insight into the wall structure design of the anodic TiO2 nanotubes in the glycerol-based electrolyte.

  5. Hemocompatibility of pseudozwitterionic polymer brushes with a systematic well-defined charge-bias control.

    Science.gov (United States)

    Jhong, Jheng-Fong; Sin, Mei-Chan; Kung, Hsiao-Han; Chinnathambi, Arunachalam; Alharbi, Sulaiman Ali; Chang, Yung

    2014-01-01

    In this study, a pseudozwitterionic surface bearing positively and negatively mixed charged moieties was developed as a potential hemocompatible material for biomedical applications. In this work, hemocompatility of pseudozwitterionic surface prepared from copolymerization of negatively charged 3-sulfopropyl methacrylate (SA) and positively charged [2-(methacryloyloxy)ethyl] trimethylammonium (TMA) was delineated. Mixed charge distribution in the prepared poly(TMA-co-SA)-grafted surface can be controlled by regulating TMA and SA monomer ratios via surface-initiated atom transfer radical polymerization. The effects of grafting composition and charge bias variations on blood compatibility of poly(TMA-co-SA)-grafted surface were reported. The protein adsorption on different poly(TMA-co-SA)-grafted surfaces from human plasma protein (fibrinogen, HSA, and γ-globulin) solutions was evaluated using an enzyme-linked immunosorbent assay. Blood platelet adhesion and time measurements on plasma clotting were conducted to determine the platelet activation on the grafted surface. It was found that the protein resistance and anti-blood cell adhesion of prepared surface can be precisely controlled by controlling the charge balance of TMA/SA compositions. In addition, different charge bias variations on the poly(TMA-co-SA)-grafted surface would induce electrostatic interactions between plasma proteins and prepared surfaces which lead to adsorptions of interfacial protein and blood cells, plasma clotting, and blood cell hemolysis. Results from this study suggest that the hemocompatility of mixed charged poly(TMA-co-SA)-grafted surface depends on the charge bias level. This provides a great potential for designing biomaterial with unique surface chemical structure which could be used in contact with human blood.

  6. Non-biofouling property of well-defined concentrated polymer brushes.

    Science.gov (United States)

    Yoshikawa, Chiaki; Qiu, Jun; Huang, Chih-Feng; Shimizu, Yoshihisa; Suzuki, Junji; van den Bosch, Edith

    2015-03-01

    The non-biofouling properties of polymer brushes of poly(2-hydroxyethyl methacrylate) (PHEMA), poly(2-hydroxyethyl acrylate) (PHEA), and poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMA) were comprehensively studied by varying graft densities (i.e., semi-dilute and concentrated regimes) and the thicknesses at the dry state of 2 and 10 nm. Semi-dilute polymer brushes (SDPBs) were prepared by grafting-to method and concentrated polymer brushes (CPBs) were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). The adsorptions of proteins with different sizes were investigated on the brushes by quartz crystal microbalance (QCM) from a view point of size-exclusion effect specific to the CPBs. We confirmed that due to the size exclusion effect, the CPBs of all the three much suppressed proteins adsorption and human umbilical vein endothelial cell (HUVEC) adhesion compared with the corresponding SDPBs. In order to investigate what type of proteins adsorbed on the brushes to trigger cell adhesion, we identified adsorbed proteins from fetal bovine serum on the brushes using a high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Proteins were only detected on the SDPBs. Interestingly, the number and type of identified proteins were different on the SDPBs, indicating that chemical composition of the SDPBs affects protein adsorption, hence the cell adhesion. The adsorption mechanism on the SDPBs could be due to the combination of protein-polymer interaction and physical inclusion, whereas CPBs exhibit size exclusion effect combined with neutral hydrophilic nature of polymer, thereby, that provides excellent non-biofouling property.

  7. MARIOS: Irradiation of UO{sub 2} containing 15% americium at well defined temperature

    Energy Technology Data Exchange (ETDEWEB)

    D' Agata, E., E-mail: elio.dagata@ec.europa.eu [European Commission, Joint Research Centre, Institute for Energy - P.O. Box 2, 1755 ZG Petten (Netherlands); Hania, P.R. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Bejaoui, S. [Commissariat a l' Energie Atomique, DEC CEA-Cadarache, 13108 St. Paul lez Durance Cedex (France); Sciolla, C.; Wyatt, T.; Hannink, M.H.C. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Herlet, N.; Jankowiak, A. [Commissariat a l' Energie Atomique DTEC CEA Marcoule, 30207 Bagnols sur Ceze Cedex (France); Klaassen, F.C. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Bonnerot, J.-M. [Commissariat a l' Energie Atomique, DEC CEA-Cadarache, 13108 St. Paul lez Durance Cedex (France)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer MARIOS is designed to check the behaviour of Minor Actinide Blanket Module concept. Black-Right-Pointing-Pointer Main requirement of the experiment is an accurate control of the temperature. Black-Right-Pointing-Pointer The swelling and the helium release will be the main output of the experiment. Black-Right-Pointing-Pointer A complementary experiment (DIAMINO), will be performed in the next future. - Abstract: Americium is a strong contributor to the long term radiotoxicity of high activity nuclear waste. Transmutation by irradiation in nuclear reactors of long-lived nuclides like {sup 241}Am is, therefore, an option for the reduction of radiotoxicity and residual power packages as well as the repository area. The MARIOS irradiation experiment is the latest of a series of experiments on americium transmutation (e.g. EFTTRA-T4, EFTTRA-T4bis, HELIOS). MARIOS experiment is carried out in the framework of the 4-year project FAIRFUELS of the EURATOM 7th Framework Programme (FP7). During the past years of experimental work in the field of transmutation and tests of innovative nuclear fuel containing americium, the release or trapping of helium as well as swelling has shown to be the key issue for the design of such kinds of target. Therefore, the main objective of the MARIOS experiment is to study the in-pile behaviour of UO{sub 2} containing minor actinides (MAs) in order to gain knowledge on the role of the microstructure and of the temperature on the gas release and on fuel swelling. The MARIOS experiment will be conducted in the HFR (high flux reactor) in Petten (The Netherlands) and will start in the beginning of 2011. It has been planned that the experiment will last 11 cycles, corresponding to 11 months. This paper covers the description of the objective of the experiment, as well as a general description of the design of the experiment.

  8. In situ solid-state electrochemistry of mass-selected ions at well-defined electrode–electrolyte interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Venkateshkumar; Johnson, Grant E.; Wang, Bingbing; Laskin, Julia

    2016-11-07

    Molecular-level understanding of electrochemical processes occurring at electrode-electrolyte interfaces (EEI) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and first application of solid-state in situ electrochemical probes to study redox and catalytic processes occurring at well-defined EEI generated using soft-landing of mass- and charge-selected cluster ions (SL). In situ electrochemical probes with excellent mass transfer properties are fabricated using carefully-designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy. SL is, therefore, a unique tool for studying fundamental processes occurring at EEI. For the first time using an aprotic electrochemical probe, the effect of charge state (PMo12O403-/2-) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEI with novel POM anions generated by electrospray ionization and gas phase dissociation. Additionally, a proton conducting electrochemical probe has been developed to characterize the reactive electrochemistry (oxygen reduction activity) of bare Pt clusters (Pt40 ~1 nm diameter), thus demonstrating the capability of the probe for studying reactions in controlled gaseous environments. The newly developed in situ electrochemical probes combined with ion SL provide a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely-defined conditions. This capability will advance molecular-level understanding of processes occurring at EEI that are critical to many energy-related technologies.

  9. Adsorption of biopolymers human serum albumin and human gamma globulin to well-defined surfaces of self-assembled monolayers

    Science.gov (United States)

    Cregger, Tricia Ann

    The tenacity with which the blood proteins Human Serum Albumin (HSA) and Human Gamma Globulin (HGG) adsorb to a surface modified with a monomolecular coating varies with the packing of the alkyl chains in the coating. The adsorption of proteins onto well-defined surfaces of self-assembled monolayers (SAMs) was studied with X-ray reflectometry (XR), neutron reflectometry (NR), optical reflectometry, and total internal reflection fluorescence (TIRF). NR and XR was used to study adsorption in the absence of flow, while optical reflectometry and TIRF were used to probe the adsorption under flow conditions. In particular, competitive adsorption measurements of binary solutions of HSA, HGG and Fibrinogen (FIB) were performed with TIRE The properties of the surface were varied by altering the alkyl chains' packing density and the chain end functionality of the SAMs. The depth profiles of protein concentration near the adsorbing surface measured by NR were dependent upon the chain packing density in the case of HSA. The concentration depth profile of HGG was unaltered by varying chain packing density. Measurements performed under flow using optical reflectometry showed a different behavior: the surface excess of adsorbed HSA was relatively independent of the surface packing, while the surface excess of HGG depended on the packing density of the SAM. The tenacity with which the proteins adsorbed to different functionalized surfaces was determined by attempting to remove the protein using a strong surfactant, sodium dodecyl sulfate (SDS). Ex situ XR measurements suggested that both HSA and HGG adsorb more tenaciously to a less densely-packed monolayer, almost independent of surface functionality. Two exceptions were a less densely-packed vinyl-terminated monolayer and a less densely-packed bromine-terminated monolayer, from which HSA could not be removed at all.

  10. Macromolecular Engineering: New Routes Towards the Synthesis of Well-??Defined Polyethers/Polyesters Co/Terpolymers with Different Architectures

    KAUST Repository

    Alamri, Haleema

    2016-05-18

    The primary objective of this research was to develop a new and efficient pathway for well-defined multicomponent homo/co/terpolymers of cyclic esters/ethers using an organocatalytic approach with an emphasis on the macromolecular engineering aspects of the overall synthesis. Macromolecular engineering (as discussed in the first chapter) of homo/copolymers refers to the specific tailoring of these materials for achieving an easy and reproducible synthesis that results in precise molecular characteristics, i.e. molecular weight and polydispersity, as well as specific structure and end?group choices. Precise control of these molecular characteristics will provide access to new materials that can be used for pre-targeted purposes such as biomedical applications. Among the most commonly used engineering materials are polyesters (biocompatible and biodegradable) and polyethers (biocompatible), either as homopolymers or when or copolymers with linear structures. The ability to create non-linear structures, for example stars, will open new horizons in the applications of these important polymeric materials. The second part of this thesis describes the synthesis of aliphatic polyesters, particularly polycaprolactone and polylactide, using a metal-free initiator/catalyst system. A phosphazene base (t?BuP2) was used as the catalyst for the ring-opening copolymerization of ?-aprolactone (??CL) and L,Lactide (LLA) at room temperature with a variety of protic initiators in different solvents. These studies provided important information for the design of a metal-free route toward the synthesis of polyester?based (bio) materials. The third part of the thesis describes a novel route for the one?pot synthesis of polyether-b polyester block copolymers with either a linear or a specific macromolecular architecture. Poly (styrene oxide)?b?poly(caprolactone)?b?poly(L,lactide) was prepared using this method with the goal of synthesizing poly(styrene oxide)-based materials since this

  11. In situ solid-state electrochemistry of mass-selected ions at well-defined electrode-electrolyte interfaces.

    Science.gov (United States)

    Prabhakaran, Venkateshkumar; Johnson, Grant E; Wang, Bingbing; Laskin, Julia

    2016-11-22

    Molecular-level understanding of electrochemical processes occurring at electrode-electrolyte interfaces (EEIs) is key to the rational development of high-performance and sustainable electrochemical technologies. This article reports the development and application of solid-state in situ thin-film electrochemical cells to explore redox and catalytic processes occurring at well-defined EEIs generated using soft-landing (SL) of mass- and charge-selected cluster ions. In situ cells with excellent mass-transfer properties are fabricated using carefully designed nanoporous ionic liquid membranes. SL enables deposition of pure active species that are not obtainable with other techniques onto electrode surfaces with precise control over charge state, composition, and kinetic energy. SL is, therefore, demonstrated to be a unique tool for studying fundamental processes occurring at EEIs. Using an aprotic cell, the effect of charge state ([Formula: see text]) and the contribution of building blocks of Keggin polyoxometalate (POM) clusters to redox processes are characterized by populating EEIs with POM anions generated by electrospray ionization and gas-phase dissociation. Additionally, a proton-conducting cell has been developed to characterize the oxygen reduction activity of bare Pt clusters (Pt30 ∼1 nm diameter), thus demonstrating the capability of the cell for probing catalytic reactions in controlled gaseous environments. By combining the developed in situ electrochemical cell with ion SL we established a versatile method to characterize the EEI in solid-state redox systems and reactive electrochemistry at precisely defined conditions. This capability will advance the molecular-level understanding of processes occurring at EEIs that are critical to many energy-related technologies.

  12. Poly(2-acetoxyethyl methacrylate)/polystyrene latex interpenetrating polymer networks with well-defined phase-separated structure

    Institute of Scientific and Technical Information of China (English)

    Tao Wang; Shan Shi; Li Na Bian; Li Min Zhou; Li Qun Zhao; Shin Ichi Kuroda

    2011-01-01

    A series of poly (2-acetoxyethyl methacrylate)/polystyrene (PAEMA/PS) latex interpenetrating polymer networks (LIPNs) were prepared by seeded soap-free emulsion polymerization of styrene on the crosslinked PAEMA seed particles using an oil-soluble initiator. These PAEMA/PS LIPNs showed a well-defined phase-separated structure with PS phase dispersing in continuous PAEMA phase. The domain size of PS phase was found to depend on the crosslinking degree of PAEMA seed particles and the amount of second-stage styrene monomer.

  13. Efficient removal of formaldehyde by nanosized gold on well-defined CeO₂ nanorods at room temperature.

    Science.gov (United States)

    Xu, Quanlong; Lei, Wanying; Li, Xinyang; Qi, Xiaoying; Yu, Jiaguo; Liu, Gang; Wang, Jinlong; Zhang, Pengyi

    2014-08-19

    Gold (Au) nanoparticles (NPs) supported on well-defined ceria (CeO2) nanorods with exposed {110} and {100} facets were prepared by a deposition-precipitation method and characterized by powder X-ray diffraction, micro-Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption, transmission electron microscopy, high-resolution transmission electron microscopy, and high-angle annular dark-field scanning transmission electron microscopy. Both nanometer and subnanometer gold particles were found to coexist on ceria supports with various Au contents (0.01-5.4 wt %). The catalytic performance of Au/CeO2 catalysts was examined for formaldehyde (HCHO) oxidation into CO2 and H2O at room temperature and shown to be Au content dependent, with 1.8 wt % Au/CeO2 displaying the best performance. On the basis of the results from hydrogen temperature-programmed reduction and in situ Fourier transform infrared spectroscopy observations, the high reactivity and stability of Au/CeO2 catalysts is mainly attributed to the well-defined ceria nanorods with {110} and {100} facets which present a relatively low energy for oxygen vacancy formation. Furthermore, gold NPs could induce the weakened Ce-O bond which in turn promotes HCHO oxidation.

  14. Synthesis and Characterization of Well-Defined Regular Star Polyisoprenes with 3, 4, 6 and 8 Arms

    KAUST Repository

    Ratkanthwar, Kedar R.

    2013-01-01

    Three series of regular well-defined star polyisoprenes (PIs) with 3, 4 and 6 arms (each series: same arm molecular weight) have been synthesized by anionic polymerization high vacuum techniques and chlorosilane chemistry. In addition, three linear PIs with practically the double arm molecular weight of the corresponding series (2-arm star PIs) have been synthesized, as well as one 8-arm star PI. All intermediate (arms) and final (stars) products have been characterized by size exclusion chromatography (SEC), SEC-multi-angle laser light scattering (SEC-MALLS) and nuclear magnetic resonance (NMR) spectroscopy. The Tg of the star PIs was determined by differential scanning calorimetry. These model polymeric materials are essential for polymer physics and polymer physical chemistry in order to establish the structure/property relationships.

  15. Self-assembly behavior of well-defined polymethylene-block-poly(ethylene glycol) copolymers in aqueous solution

    KAUST Repository

    Alkayal, Nazeeha

    2016-09-22

    A series of well-defined amphiphilic polymethylene-b-poly(ethylene glycol) (PM-b-PEG) diblock copolymers, with different hydrophobic chain length, were synthesized by combining Diels-Alder reaction with polyhomologation. The successful synthetic procedure was confirmed by size-exclusion chromatography (SEC) and 1H NMR spectroscopy. These block copolymers self-assembled into spherical micelles in aqueous solutions and exhibit low critical micelle concentration (CMC) of 2–4 mg/mL, as determined by fluorescence spectroscopy using pyrene as a probe. Measurements of the micelle hydrodynamic diameters, performed by dynamic light scattering (DLS), cryo-transmission electron microscopy (cryo-TEM) and atomic force microscopy (AFM), revealed a direct dependence of the micelle size from the polymethylene block length.

  16. Photometric characterization of a well defined sample of isolated galaxies in the context of the AMIGA project

    CERN Document Server

    Durbala, A; Buta, R; Verdes-Montenegro, L

    2008-01-01

    We perform a detailed photometric analysis (bulge-disk-bar decomposition and Concentration-Asymmetry-Clumpiness - CAS parametrization) for a well defined sample of isolated galaxies, extracted from the Catalog of Isolated Galaxies (Karachentseva 1973) and reevaluated morphologically in the context of the AMIGA project. We focus on Sb-Sc morphological types, as they are the most representative population among the isolated spiral galaxies. Assuming that the bulge Sersic index and/or Bulge/Total luminosity ratios are reasonable diagnostics for pseudo- versus classical bulges, we conclude that the majority of late-type isolated disk galaxies likely host pseudobulges rather than classical bulges. Our parametrization of galactic bulges and disks suggests that the properties of the pseudobulges are strongly connected to those of the disks. This may indicate that pseudobulges are formed through internal processes within the disks (i.e. secular evolution) and that bars may play an important role in their formation. A...

  17. Structure of branching enzyme- and amylomaltase modified starch produced from well-defined amylose to amylopectin substrates

    DEFF Research Database (Denmark)

    Sorndecha, Waraporn; Sagnelli, Domenico; Meier, Sebastian

    2016-01-01

    Thermostable branching enzyme (BE, EC 2.4.1.18) from Rhodothermus obamensis in combination with amylomaltase (AM, EC 2.4.1.25) from Thermus thermophilus was used to modify starch structure exploring potentials to extensively increase the number of branch points in starch. Amylose is an important...... constituent in starch and the effect of amylose on enzyme catalysis was investigated using amylose-only barley starch (AO) and waxy maize starch (WX) in well-defined ratios. All products were analysed for amylopectin chain length distribution, α-1,6 glucosidic linkages content, molar mass distribution...... by the molar mass rather that the branching density of the glucan per se . Our data demonstrate that a higher amylose content in the substrate starch efficiently produces α-1,6 glucosidic linkages and that the present of amylose generates a higher Μw and more resistant product than amylopectin. The combination...

  18. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst.

    Science.gov (United States)

    Merle, Nicolas; Le Quéméner, Frédéric; Bouhoute, Yassine; Szeto, Kai C; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja K; Delevoye, Laurent; Gauvin, Régis M; Taoufik, Mostafa; Basset, Jean-Marie

    2017-02-15

    The well-defined silica-supported molybdenum oxo alkyl species (≡SiO-)MoO(CH2(t)Bu)3 was selectively prepared by grafting of MoO(CH2(t)Bu)3Cl onto partially dehydroxylated silica (silica700) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO3/SiO2 olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  19. A versatile nanobuilding precursor for the effective architecture of well-defined organic/inorganic hybrid via click chemistry

    Institute of Scientific and Technical Information of China (English)

    Ya Kun Zhu; Shan Yi Guang; Hong Yao Xu

    2012-01-01

    A novel octazido substituted nanobuilding precursor,octakis[dimethy(p-azidomethylene)siloxyl]octasilsesquioxane (ODA),was prepared by the conventional diazo-transfer reaction of octakis[dimethy(p-chloromethylene)silyl]octasilsesquioxane (ODC)with NaN3,and its structure was characterized by FT-IR,1H,13C,29Si NMR and MALDI-TOF MS,respectively.The structural rearrangement of POSS core in the synthesis strategy of ODA developed in this work was effectively prohibited in comparison with traditionary azidization process.The resultant ODA was not only soluble in common solvents such as CHCl3,THF,toluene,DMF and DMSO,but also could effectively serve as a versatile nanobuilding precursor for the architecture of well-defined organicinorganic hybrids via click chemistry.

  20. Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated polymers.Because the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth mechanism.With this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been prepared.Especially,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block copolymers.In the current review,the progress in this new area is summarized.

  1. Synthesis and Biological Evaluation of Well-Defined Poly(propylene fumarate) Oligomers and Their Use in 3D Printed Scaffolds.

    Science.gov (United States)

    Luo, Yuanyuan; Dolder, Courtney K; Walker, Jason M; Mishra, Ruchi; Dean, David; Becker, Matthew L

    2016-02-08

    A ring opening polymerization method for synthesizing oligomeric poly(propylene fumarate) (PPF) provides a rapid, and scalable method of synthesizing PPF with well-defined molecular mass, molecular mass distribution (Đm), and viscosity properties suitable for 3D printing. These properties will also reduce the amount of solvent necessary to ensure sufficient flow of material during 3D printing. MALDI mass spectrometry precisely shows the end group fidelity, and size exclusion chromatography (SEC) demonstrates narrow mass distributions (3000 Da). The corresponding intrinsic viscosities range from 0.0288 ± 0.0009 dL/g to 0.0780 ± 0.0022 dL/g. The oligomers were printed into scaffolds via established photochemical methods and standardized ISO 10993-5 testing shows that the 3D printed materials are nontoxic to both L929 mouse fibroblasts and human mesenchymal stem cells.

  2. Well-defined silica supported bipodal molybdenum oxo alkyl complexes: a model of the active sites of industrial olefin metathesis catalysts

    KAUST Repository

    Merle, Nicolas

    2017-09-25

    A well-defined, silica-supported molybdenum oxo alkyl species, ([triple bond, length as m-dash]SiO-)2Mo([double bond, length as m-dash]O)(CH2tBu)2, was prepared by the selective grafting of Mo([double bond, length as m-dash]O)(CH2tBu)3Cl onto a silica partially dehydroxylated at 200 °C using a rigorous surface organometallic chemistry approach. The immobilized bipodal surface species, partly resembling the active species of industrial MoO3/SiO2 olefin metathesis catalysts, exhibited excellent functional group tolerance in conjunction with its high activity in homocoupling, self and ring closing olefin metathesis.

  3. Well-defined Polymethylene-Based Co/Terpolymers by Combining Anthracene/Maleimide Diels-Alder Reaction with Polyhomologation

    KAUST Repository

    Hadjichristidis, Nikolaos

    2015-05-26

    A novel strategy towards well-defined polymethylene-based co/terpolymers, by combining anthracene/maleimide Diels-Alder reaction with polyhomologation, is presented. For the synthesis of diblock copolymers the following approach was applied: a) synthesis of α-anthracene-ω-hydroxy- polymethylene by polyhomologation using tri (9-anthracene-methyl propyl ether) borane as initiator, b) synthesis of furan-protected-maleimide-terminated poly (ε-caprolactone) or polyethylene glycol and c). Diels-Alder reaction between the anthracene and maleimide-terminated polymers. In the case of triblock terpolymers the α-anthracene-ω-hydroxy-polymethylene was used as macroinitiator for the ring-opening polymerization of D, L-lactide to afford an anthracene-terminated PM-b-PLA copolymer, followed by Diels-Alder reaction with furan-protected maleimide-terminated poly (ε-caprolactone) or polyethylene glycol to give the triblock terpolymers. All intermediate and final products were characterized by SEC, 1H NMR, UV-VIS spectroscopy and DSC.

  4. Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation.

    Science.gov (United States)

    Hou, Wenpeng; Zhao, Ning-Jiu; Meng, Dongli; Tang, Jing; Zeng, Yi; Wu, Yu; Weng, Yangziwan; Cheng, Chungui; Xu, Xiulai; Li, Yi; Zhang, Jian-Ping; Huang, Yong; Bielawski, Christopher W; Geng, Jianxin

    2016-05-24

    The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.

  5. Morphological Studies on Sn-O Coordination Driving Self-assembly of Well-defined Organotin-containing Block Copolymers

    Institute of Scientific and Technical Information of China (English)

    Jian Jiang; Wei Yan; Ling-yan Liu; Wei-xing Chang; Jing Li

    2014-01-01

    A tin-oxygen coordination driving self-assembly was developed in the block copolymers containing organotin,which were prepared by the radical addition-fraction transfer (RAFT) method and characterized by the gel-permeation chromatography (GPC) and 1H-NMR.And the self-assemblies of these block copolymers with various chain length ratios in the different concenaations in CHCl3 were stable according to the results of DLS and TEM.Additionally,it was also given an insight investigation on the regulation of self-assembly of the block copolymers by adding dibutyltin dichloride and a possible mechanism was proposed.

  6. Well-Defined Nanostructured, Single-Crystalline TiO2 Electron Transport Layer for Efficient Planar Perovskite Solar Cells.

    Science.gov (United States)

    Choi, Jongmin; Song, Seulki; Hörantner, Maximilian T; Snaith, Henry J; Park, Taiho

    2016-06-28

    An electron transporting layer (ETL) plays an important role in extracting electrons from a perovskite layer and blocking recombination between electrons in the fluorine-doped tin oxide (FTO) and holes in the perovskite layers, especially in planar perovskite solar cells. Dense TiO2 ETLs prepared by a solution-processed spin-coating method (S-TiO2) are mainly used in devices due to their ease of fabrication. Herein, we found that fatal morphological defects at the S-TiO2 interface due to a rough FTO surface, including an irregular film thickness, discontinuous areas, and poor physical contact between the S-TiO2 and the FTO layers, were inevitable and lowered the charge transport properties through the planar perovskite solar cells. The effects of the morphological defects were mitigated in this work using a TiO2 ETL produced from sputtering and anodization. This method produced a well-defined nanostructured TiO2 ETL with an excellent transmittance, single-crystalline properties, a uniform film thickness, a large effective area, and defect-free physical contact with a rough substrate that provided outstanding electron extraction and hole blocking in a planar perovskite solar cell. In planar perovskite devices, anodized TiO2 ETL (A-TiO2) increased the power conversion efficiency by 22% (from 12.5 to 15.2%), and the stabilized maximum power output efficiency increased by 44% (from 8.9 to 12.8%) compared with S-TiO2. This work highlights the importance of the ETL geometry for maximizing device performance and provides insights into achieving ideal ETL morphologies that remedy the drawbacks observed in conventional spin-coated ETLs.

  7. Surface modification with well-defined biocompatible triblock copolymers Improvement of biointerfacial phenomena on a poly(dimethylsiloxane) surface.

    Science.gov (United States)

    Iwasaki, Yasuhiko; Takamiya, Mika; Iwata, Ryoko; Yusa, Shin-Ichi; Akiyoshi, Kazunari

    2007-06-15

    To improve interfacial phenomena of poly(dimethylsiloxane) (PDMS) as biomaterials, well-defined triblock copolymers were prepared as coating materials by reversible addition-fragmentation chain transfer (RAFT) controlled polymerization. Hydroxy-terminated poly(vinylmethylsiloxane-co-dimethylsiloxane) (HO-PV(l)D(m)MS-OH) was synthesized by ring-opening polymerization. The copolymerization ratio of vinylmethylsiloxane to dimethylsiloxane was 1/9. The molecular weight of HO-PV(l)D(m)MS-OH ranged from (1.43 to 4.44)x10(4), and their molecular weight distribution (M(w)/M(n)) as determined by size-exclusion chromatography equipped with multiangle laser light scattering (SEC-MALS) was 1.16. 4-Cyanopentanoic acid dithiobenzoate was reacted with HO-PV(l)D(m)MS-OH to obtain macromolecular chain transfer agents (macro-CTA). 2-Methacryloyloxyethyl phosphorylcholine (MPC) was polymerized with macro-CTAs. The gel-permeation chromatography (GPC) chart of synthesized polymers was a single peak and M(w)/M(n) was relatively narrow (1.3-1.6). Then the poly(MPC) (PMPC)-PV(l)D(m)MS-PMPC triblock copolymers were synthesized. The molecular weight of PMPC in a triblock copolymer was easily controllable by changing the polymerization time or the composition of the macro-CTA to a monomer in the feed. The synthesized block copolymers were slightly soluble in water and extremely soluble in ethanol and 2-propanol. Surface modification was performed via hydrosilylation. The block copolymer was coated on the PDMS film whose surface was pretreated with poly(hydromethylsiloxane). The surface wettability and lubrication of the PDMS film were effectively improved by immobilization with the block copolymers. In addition, the number of adherent platelets from human platelet-rich plasma (PRP) was dramatically reduced by surface modification. Particularly, the triblock copolymer having a high composition ratio of MPC units to silicone units was effective in improving the surface properties of PDMS. By

  8. Well-defined 4-arm stars with hydroxy-terminated polyethylene, polyethylene-b-polycaprolactone and polyethylene-b-(polymethyl methacrylate) 2 arms

    KAUST Repository

    Zhang, Zhen

    2016-07-20

    Bis-boron-thexyl-silaboracycle was prepared by hydroboration of 1,4-bis(methyldivinylsilyl)butane with thexylborane and used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined hydroxy-terminated 4-arm polyethylene (PE) stars. The synthesized PE stars were transformed to (PE-b-PCL)4 starblock copolymers via the ring-opening polymerization of ϵ-caprolactone (CL) initiated by the hydroxyl end groups of (PE-OH)4 in the presence of P2-tBu phosphazene base. Esterification of the hydroxyl groups of the OH-terminated PE star with 2,2-dichloroacetyl chloride led to (PE-Cl2)4 which was used as initiator (eight initiating atom transfer radical polymerization, ATRP, sites) for the synthesis of (PE-b-PMMA2)4 dendrimer-like stars by the ATRP of methyl methacrylate (MMA). All intermediates and final products were characterized by high temperature gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. © 2016 The Royal Society of Chemistry.

  9. Preparation of Well-Defined Propargyl-Terminated Tetra-Arm Poly(N-isopropylacrylamides and Their Click Hydrogels Crosslinked with β-cyclodextrin

    Directory of Open Access Journals (Sweden)

    Jianquan Wang

    2016-03-01

    Full Text Available As an important class of reversible deactivation radical polymerization (RDRP, reversible addition fragmentation chain transfer (RAFT polymerization has attracted great attention attributed to its facile and flexible features to prepare well-defined polymers with different complex structures. In addition, the combination of RAFT with click chemistry provides more effective strategies to fabricate advanced functional materials. In this work, a series of temperature responsive tetra-arm telechelic poly(N-isopropylacrylamides (PNIPAs with propargyl end groups were prepared for the first time through RAFT and subsequent aminolysis/Michael addition modification. The temperature sensitivities of their aqueous solutions were researched via turbidity measurement. It was found that the phase transition temperature of obtained PNIPAs increased with their molecular weights ascribed to their distinctions in the hydrophobic/hydrophilic balance. Subsequently, β-cyclodextrin (β-CD functionalized with azide moieties was used to crosslink the prepared propargyl-terminated tetra-arm PNIPAs through click chemistry, fabricating corresponding hydrogels with thermoresponse. Similar to their precursors, the hydrogels demonstrated the same dependence of volume phase transition temperature (VPTT on their molecular weights. In addition, the incorporation of β-CD and the residual groups besides crosslinking may provide a platform for imparting additional functions such as inclusion and adsorption as well as further functionalization.

  10. Synthesis of Well-defined Long Chain Branched Polyethylene via Anionic Polymerization Combined with Graft-onto Method

    Institute of Scientific and Technical Information of China (English)

    LIU Feng; WANG Lu; ZHANG Guang-chun; ZHENG Jun; TANG Tao

    2013-01-01

    Comb-like polyethylene(PE) was prepared via anionic polymerization combined with "graft-onto" process.The polybutadiene(PB) backbone underwent hydroxylation at 1,2-vinyl groups to obtain a controlled number of hydroxyl groups along the main chain.After the translation of hydroxyl groups to tosyl groups,a nucteophilic substitution by living anionic PB chains was achieved.The comb PE was finally obtained by the hydrogenation of the obtained unsaturated comb polymer.Since the living anionic polymerization was used to prepare the backbones and the branch chains,molecular weight to molecular weight distribution(Mw/Mn<l.5) can be well-controlled in the final comb polymer,including the average number and length of branches.

  11. Spatially well-defined binary brushes of poly(ethylene glycol)s for micropatterning of active proteins on anti-fouling surfaces.

    Science.gov (United States)

    Xu, F J; Li, H Z; Li, J; Teo, Y H Eric; Zhu, C X; Kang, E T; Neoh, K G

    2008-12-01

    We report a novel method for micropatterning of active proteins on anti-fouling surfaces via spatially well-defined and dense binary poly(ethylene glycol)s (PEGs) brushes with controllable protein-docking sites. Binary brushes of poly(poly(ethylene glycol) methacrylate-co-poly(ethylene glycol)methyl ether methacrylate), or P(PEGMA-co-PEGMEMA), and poly(poly(ethylene glycol)methyl ether methacrylate), or P(PEGMEMA), were prepared via consecutive surface-initiated atom transfer radical polymerizations (SI-ATRPs) from a resist-micropatterned Si(100) wafer surface. The terminal hydroxyl groups on the side chains of PEGMA units in the P(PEGMA-co-PEGMEMA) microdomains were activated directly by 1,1'-carbonyldiimidazole (CDI) for the covalent coupling of human immunoglobulin (IgG) (as a model active protein). The resulting IgG-coupled PEG microdomains interact only and specifically with target anti-IgG, while the other PEG microregions effectively prevent specific and non-specific protein fouling. When extended to other active biomolecules, microarrays for specific and non-specific analyte interactions with a high signal-to-noise ratio could be readily tailored.

  12. The importance of chemistry in creating well-defined nanoscopic embedded therapeutics: devices capable of the dual functions of imaging and therapy.

    Science.gov (United States)

    Nyström, Andreas M; Wooley, Karen L

    2011-10-18

    Nanomedicine is a rapidly evolving field, for which polymer building blocks are proving useful for the construction of sophisticated devices that provide enhanced diagnostic imaging and treatment of disease, known as theranostics. These well-defined nanoscopic objects have high loading capacities, can protect embedded therapeutic cargo, and offer control over the conditions and rates of release. Theranostics also offer external surface area for the conjugation of ligands to impart stealth characteristics and/or direct their interactions with biological receptors and provide a framework for conjugation of imaging agents to track delivery to diseased site(s). The nanoscopic dimensions allow for extensive biological circulation. The incorporation of such multiple functions is complicated, requiring exquisite chemical control during production and rigorous characterization studies to confirm the compositions, structures, properties, and performance. We are particularly interested in the study of nanoscopic objects designed for treatment of lung infections and acute lung injury, urinary tract infections, and cancer. This Account highlights our work over several years to tune the assembly of unique nanostructures. We provide examples of how the composition, structure, dimensions, and morphology of theranostic devices can tune their performance as drug delivery agents for the treatment of infectious diseases and cancer. The evolution of nanostructured materials from relatively simple overall shapes and internal morphologies to those of increasing complexity is driving the development of synthetic methodologies for the preparation of increasingly complex nanomedicine devices. Our nanomedicine devices are derived from macromolecules that have well-defined compositions, structures, and topologies, which provide a framework for their programmed assembly into nanostructures with controlled sizes, shapes, and morphologies. The inclusion of functional units within selective

  13. In-depth analysis of protein inference algorithms using multiple search engines and well-defined metrics.

    Science.gov (United States)

    Audain, Enrique; Uszkoreit, Julian; Sachsenberg, Timo; Pfeuffer, Julianus; Liang, Xiao; Hermjakob, Henning; Sanchez, Aniel; Eisenacher, Martin; Reinert, Knut; Tabb, David L; Kohlbacher, Oliver; Perez-Riverol, Yasset

    2017-01-06

    In mass spectrometry-based shotgun proteomics, protein identifications are usually the desired result. However, most of the analytical methods are based on the identification of reliable peptides and not the direct identification of intact proteins. Thus, assembling peptides identified from tandem mass spectra into a list of proteins, referred to as protein inference, is a critical step in proteomics research. Currently, different protein inference algorithms and tools are available for the proteomics community. Here, we evaluated five software tools for protein inference (PIA, ProteinProphet, Fido, ProteinLP, MSBayesPro) using three popular database search engines: Mascot, X!Tandem, and MS-GF+. All the algorithms were evaluated using a highly customizable KNIME workflow using four different public datasets with varying complexities (different sample preparation, species and analytical instruments). We defined a set of quality control metrics to evaluate the performance of each combination of search engines, protein inference algorithm, and parameters on each dataset. We show that the results for complex samples vary not only regarding the actual numbers of reported protein groups but also concerning the actual composition of groups. Furthermore, the robustness of reported proteins when using databases of differing complexities is strongly dependant on the applied inference algorithm. Finally, merging the identifications of multiple search engines does not necessarily increase the number of reported proteins, but does increase the number of peptides per protein and thus can generally be recommended.

  14. A facile glovebox-free strategy to significantly accelerate the syntheses of well-defined polypeptides by N-carboxyanhydride (NCA) ring opening polymerizations.

    Science.gov (United States)

    Zou, Jiong; Fan, Jingwei; He, Xun; Zhang, Shiyi; Wang, Hai; Wooley, Karen L

    2013-05-28

    A facile N2 flow-accelerated N-carboxyanhydride ring opening polymerization (NCA ROP) is demonstrated, herein, with rigorous kinetic studies to evaluate the methodology in detail. By using n-hexylamine as initiator and γ-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) as monomer, the NCA ROP via a normal amine mechanism (NAM) reached 90% conversion in 2 h under N2 flow at room temperature in a fume hood, much shorter than the time required for the same polymerization conducted in a glove box (14 h). The efficient removal of CO2 from the reaction by N2 flow drove the carbamic acid-amine equilibrium toward the formation of active nucleophilic amino termini and promoted polymerization. The detailed kinetic studies of the polymerization with different feed ratios and N2 flow rates were conducted, demonstrating the living feature of the NCA ROP and the tuning of the polymerization rate by simply changing the flow rate of N2. Maintenance of the reactivity of the amino ω-chain terminus and control during a subsequent polymerization were confirmed by performing chain extension reactions. The N2 flow method provides a new straightforward strategy to synthesize well-defined polypeptides with predictable molecular weights and narrow molecular weight distributions (PDI < 1.19).

  15. Well-defined bis(phenolate)lanthanide methoxides as efficient initiators for the polymerization of cyclic carbonate and lactide

    Institute of Scientific and Technical Information of China (English)

    XU XiaoPing; YAO YingMing; ZHANG Yong; SHEN Qi

    2007-01-01

    Lanthanide methoxides supported by carbon-bridged bis(phenolate)ligands 2,2'-methylene-bis(6-tert-butyl-4-methylphenoxo)(MBMP2-)[(MBMP)Ln(μ-OMe)(THF)2]2(Ln=Nd(1),Yb(2))were synthesized in high yields by the protolysis reaction using(C5H5)3Ln(THF)as starting materials,and complex 1 was structurally characterized.The coordination geometry around the center metal can be best described as a distorted octahedron.Complexes 1 and 2 were shown to be efficient initiators for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate(DTC)and L-lactide.The mechanism of DTC polymerization was explored by the end group analysis of the oligomer.

  16. Design and Synthesis of Structurally Well-Defined Functional Polyolefins via Transition Metal- Mediated Olefin Polymerization Chemistry

    Institute of Scientific and Technical Information of China (English)

    JinYong Dong

    2005-01-01

    @@ 1Introduction In fact, ever since the commercialization of PE and PP in the 1950s, the functionalization of polyolefins has been a very interesting research subject attracting attentions from both academic and industrial communities. The so-called polyolefin functionalization is explained as introducing polar functional groups into polyolefins. With the precondition of maintaining the desired properties of polyolefins, polyolefin functionalization confers reactivity to polyolefins, improving adhesion and compatibility between polyolefins and other materials, such as pigments, paints, glass fibers, metals, carbon black, and most polymers. The application of polyolefins after functionalization can be extended to such areas that even involve catalyst supporting, medicament, photoelectron material, biomaterial, photo material, and environmental protection, which have never been previously accessed by polyolefins.

  17. ON THE NOTION OF WELL-DEFINED TECTONIC REGIMES FOR TERRESTRIAL PLANETS IN THIS SOLAR SYSTEM AND OTHERS

    Energy Technology Data Exchange (ETDEWEB)

    Lenardic, A. [Department of Earth Science, Rice University, MS 126, P.O. Box 1892, Houston, TX 77251-1892 (United States); Crowley, J. W., E-mail: ajns@rice.edu, E-mail: jwgcrowley@gmail.com [Department of Earth and Planetary Science, Harvard University, 20 Oxford St., Cambridge, MA 02138 (United States)

    2012-08-20

    A model of coupled mantle convection and planetary tectonics is used to demonstrate that history dependence can outweigh the effects of a planet's energy content and material parameters in determining its tectonic state. The mantle convection-surface tectonics system allows multiple tectonic modes to exist for equivalent planetary parameter values. The tectonic mode of the system is then determined by its specific geologic and climatic history. This implies that models of tectonics and mantle convection will not be able to uniquely determine the tectonic mode of a terrestrial planet without the addition of historical data. Historical data exists, to variable degrees, for all four terrestrial planets within our solar system. For the Earth, the planet with the largest amount of observational data, debate does still remain regarding the geologic and climatic history of Earth's deep past but constraints are available. For planets in other solar systems, no such constraints exist at present. The existence of multiple tectonic modes, for equivalent parameter values, points to a reason why different groups have reached different conclusions regarding the tectonic state of extrasolar terrestrial planets larger than Earth ({sup s}uper-Earths{sup )}. The region of multiple stable solutions is predicted to widen in parameter space for more energetic mantle convection (as would be expected for larger planets). This means that different groups can find different solutions, all potentially viable and stable, using identical models and identical system parameter values. At a more practical level, the results argue that the question of whether extrasolar terrestrial planets will have plate tectonics is unanswerable and will remain so until the temporal evolution of extrasolar planets can be constrained.

  18. Grafting oligothiophenes on surfaces by diazonium electroreduction: a step toward ultrathin junction with well-defined metal/oligomer interface.

    Science.gov (United States)

    Stockhausen, Verena; Ghilane, Jalal; Martin, Pascal; Trippé-Allard, Gaelle; Randriamahazaka, Hyacinthe; Lacroix, Jean-Christophe

    2009-10-21

    The functionalization of electrode materials through diazonium electroreduction using a heteroaromatic compound, without phenyl groups, has been investigated for the first time. The electrochemical reduction of 2-aminoterthiophenyldiazonium cation, generated in situ, coats the electrode (glassy carbon (GC), gold or platinum) with an ultrathin organic layer, shown by X-ray photoelectron spectroscopy (XPS) of that deposited on gold to consist of terthiophene or oligothiophene. The coating is electroactive at potential close to that of terthiophene in solution. The electrochemical response of the modified GC electrode in the presence of various reversible redox couples shows that the attached layer acts as a conductive switch. It behaves as a barrier to electron transfer when the standard redox potential is below 0.5 V/SCE; in this case diode-like behavior is observed. However, for more oxidizing redox probes the layer can be considered as transparent and no barrier effect is observed. The layer deposited on a platinum ultramicroelectrode (UME) behaves similarly to that obtained on the large GC electrode. Scanning electrochemical microscopy (SECM) can be performed using this electroswitchable modified platinum UME which can act as a filter toward competitive redox exchange pathways.

  19. A model electrode of well-defined geometry prepared by direct laser-induced decoration of nanoporous templates with Au-Ag@C nanoparticles

    Science.gov (United States)

    Schlicht, Stefanie; Kireev, Alexey; Vasileva, Anna; Grachova, Elena V.; Tunik, Sergey P.; Manshina, Alina A.; Bachmann, Julien

    2017-02-01

    We present an original type of model electrode system consisting of bimetallic Au-Ag nanoparticles embedded in an amorphous carbon matrix with an extremely well-defined geometry of parallel, straight, cylindrical macropores. The samples are prepared in one step by direct laser deposition of the metal/carbon composite onto the inner walls of a porous ‘anodic’ alumina matrix serving as a template. The coating is homogeneous from top to bottom of the pores, and the amount of material deposited can be tuned by the duration of the deposition procedure. As a test system, we demonstrate that a bimetallic Ag-Au@C system is catalytically active for the electrochemical oxidation of glucose in alkaline solution, the anodic reaction of a direct glucose fuel cell. Furthermore, the electrocatalytic current density increases with the amount of Ag-Au@C NPs deposited, up to a point at which the pores are clogged with it. This type of model system allows for the systematic study of geometric effects in fuel cell electrodes. It can be generalized to a number of different nanoparticle compositions, and thereby, to various electrocatalytic reactions.

  20. Rational and practical exfoliation of graphite using well-defined poly(3-hexylthiophene) for the preparation of conductive polymer/graphene composite.

    Science.gov (United States)

    Iguchi, Hiroki; Higashi, Chisato; Funasaki, Yuichi; Fujita, Keisuke; Mori, Atsunori; Nakasuga, Akira; Maruyama, Tatsuo

    2017-01-06

    Processing and manipulation of highly conductive pristine graphene in large quantities are still major challenges in the practical application of graphene for electric device. In the present study, we report the liquid-phase exfoliation of graphite in toluene using well-defined poly(3-hexylthiophene) (P3HT) to produce a P3HT/graphene composite. We synthesize and use regioregular P3HT with controlled molecular weights as conductive dispersants for graphene. Simple ultrasonication of graphite flakes with the P3HT successfully produces single-layer and few-layer graphene sheets dispersed in toluene. The produced P3HT/graphene composite can be used as conductive graphene ink, indicating that the P3HT/graphene composite has high electrical conductivity owing to the high conductivity of P3HT and graphene. The P3HT/graphene composite also works as an oxidation-resistant and conductive film for a copper substrate, which is due to the high gas-barrier property of graphene.

  1. Rational and practical exfoliation of graphite using well-defined poly(3-hexylthiophene) for the preparation of conductive polymer/graphene composite

    Science.gov (United States)

    Iguchi, Hiroki; Higashi, Chisato; Funasaki, Yuichi; Fujita, Keisuke; Mori, Atsunori; Nakasuga, Akira; Maruyama, Tatsuo

    2017-01-01

    Processing and manipulation of highly conductive pristine graphene in large quantities are still major challenges in the practical application of graphene for electric device. In the present study, we report the liquid-phase exfoliation of graphite in toluene using well-defined poly(3-hexylthiophene) (P3HT) to produce a P3HT/graphene composite. We synthesize and use regioregular P3HT with controlled molecular weights as conductive dispersants for graphene. Simple ultrasonication of graphite flakes with the P3HT successfully produces single-layer and few-layer graphene sheets dispersed in toluene. The produced P3HT/graphene composite can be used as conductive graphene ink, indicating that the P3HT/graphene composite has high electrical conductivity owing to the high conductivity of P3HT and graphene. The P3HT/graphene composite also works as an oxidation-resistant and conductive film for a copper substrate, which is due to the high gas-barrier property of graphene.

  2. Photodeposition of platinum nanoparticles on well-defined Tungsten oxide: controlling oxidation state, particle size and geometrical distribution

    NARCIS (Netherlands)

    Wenderich, Kasper

    2016-01-01

    In this thesis, structure-directed photodeposition of the cocatalyst platinum (Pt) on monoclinic tungsten oxide (WO3) nanoplates is described, both considering fundamental aspects, as well as usefulness for applications in photocatalytic propane oxidation. Before such studies are described, the conc

  3. Fulleretic Well-Defined Scaffolds: Donor–Fullerene Alignment Through Metal Coordination and Its Effect on Photophysics

    OpenAIRE

    Williams, Derek E.; Dolgopolova, Ekaterina A.; Godfrey, Danielle C.; Ermolaeva, Evgeniya D.; Pellechia, Perry J.; Greytak, Andrew B.; Smith, Mark D.; Avdoshenko, Stanislav M.; Popov, Alexey A; Shustova, Natalia B.

    2016-01-01

    Herein, we report the first example of a crystalline metal–donor–fullerene framework, in which control of the donor–fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The 13C cross-polarization magic-angle spinning NMR spectroscopy, X-ray diffraction, and time-resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy-transfer (ET) studies of the fulleretic donor–acceptor...

  4. Terminal Uranium(V/VI) Nitride Activation of Carbon Dioxide and Carbon Disulfide: Factors Governing Diverse and Well-Defined Cleavage and Redox Reactions.

    Science.gov (United States)

    Cleaves, Peter A; Kefalidis, Christos E; Gardner, Benedict M; Tuna, Floriana; McInnes, Eric J L; Lewis, William; Maron, Laurent; Liddle, Stephen T

    2017-02-24

    The reactivity of terminal uranium(V/VI) nitrides with CE2 (E=O, S) is presented. Well-defined C=E cleavage followed by zero-, one-, and two-electron redox events is observed. The uranium(V) nitride [U(Tren(TIPS) )(N)][K(B15C5)2 ] (1, Tren(TIPS) =N(CH2 CH2 NSiiPr3 )3 ; B15C5=benzo-15-crown-5) reacts with CO2 to give [U(Tren(TIPS) )(O)(NCO)][K(B15C5)2 ] (3), whereas the uranium(VI) nitride [U(Tren(TIPS) )(N)] (2) reacts with CO2 to give isolable [U(Tren(TIPS) )(O)(NCO)] (4); complex 4 rapidly decomposes to known [U(Tren(TIPS) )(O)] (5) with concomitant formation of N2 and CO proposed, with the latter trapped as a vanadocene adduct. In contrast, 1 reacts with CS2 to give [U(Tren(TIPS) )(κ(2) -CS3 )][K(B15C5)2 ] (6), 2, and [K(B15C5)2 ][NCS] (7), whereas 2 reacts with CS2 to give [U(Tren(TIPS) )(NCS)] (8) and "S", with the latter trapped as Ph3 PS. Calculated reaction profiles reveal outer-sphere reactivity for uranium(V) but inner-sphere mechanisms for uranium(VI); despite the wide divergence of products the initial activation of CE2 follows mechanistically related pathways, providing insight into the factors of uranium oxidation state, chalcogen, and NCE groups that govern the subsequent divergent redox reactions that include common one-electron reactions and a less-common two-electron redox event. Caution, we suggest, is warranted when utilising CS2 as a reactivity surrogate for CO2 .

  5. Community Structure in Large Networks: Natural Cluster Sizes and the Absence of Large Well-Defined Clusters

    CERN Document Server

    Leskovec, Jure; Dasgupta, Anirban; Mahoney, Michael W

    2008-01-01

    A large body of work has been devoted to defining and identifying clusters or communities in social and information networks. We explore from a novel perspective several questions related to identifying meaningful communities in large social and information networks, and we come to several striking conclusions. We employ approximation algorithms for the graph partitioning problem to characterize as a function of size the statistical and structural properties of partitions of graphs that could plausibly be interpreted as communities. In particular, we define the network community profile plot, which characterizes the "best" possible community--according to the conductance measure--over a wide range of size scales. We study over 100 large real-world social and information networks. Our results suggest a significantly more refined picture of community structure in large networks than has been appreciated previously. In particular, we observe tight communities that are barely connected to the rest of the network ...

  6. Isolation and Characterization of Well-Defined Silica-Supported Azametallacyclopentane: A Key Intermediate in Catalytic Hydroaminoalkylation Reactions

    KAUST Repository

    Hamzaoui, Bilel

    2015-09-25

    Intermolecular catalytic hydroaminoalkylation of unactivated alkene occurs with silica-supported azazirconacyclopropane [[TRIPLE BOND]Si[BOND]O[BOND]Zr(HNMe2)(η2-NMeCH2)(NMe2)]. Mechanistic studies were conducted using surface organometallic chemistry (SOMC) concepts to identify the key surface intermediates. The azametallacyclopentene intermediate {[TRIPLE BOND]Si[BOND]O[BOND]Zr(HNMe2)[η2-NMeCH2CH(Me)CH2](NMe2)} was isolated after treating with 1-propylene and characterized by FT-IR spectroscopy, elemental analysis, 1H 13C HETCOR, DARR SS-NMR and DQ TQ SS-NMR. The regeneration of the catalyst was conducted by dimethylamine protonolysis to yield the pure amine.

  7. Surface Structure Dependence of SO 2 Interaction with Ceria Nanocrystals with Well-Defined Surface Facets

    Energy Technology Data Exchange (ETDEWEB)

    Tumuluri, Uma; Li, Meijun; Cook, Brandon G.; Sumpter, Bobby; Dai, Sheng; Wu, Zili

    2015-12-31

    The effects of the surface structure of ceria (CeO2) on the nature, strength, and amount of species resulting from SO2 adsorption were studied using in situ IR and Raman spectroscopies coupled with mass spectrometry, along with first-principles calculations based on density functional theory (DFT). CeO2 nanocrystals with different morphologies, namely, rods (representing a defective structure), cubes (100 facet), and octahedra (111 facet), were used to represent different CeO2 surface structures. IR and Raman spectroscopic studies showed that the structure and binding strength of adsorbed species from SO2 depend on the shape of the CeO2 nanocrystals. SO2 adsorbs mainly as surface sulfites and sulfates at room temperature on CeO2 rods, cubes, and octahedra that were either oxidatively or reductively pretreated. The formation of sulfites is more evident on CeO2 octahedra, whereas surface sulfates are more prominent on CeO2 rods and cubes. This is explained by the increasing reducibility of the surface oxygen in the order octahedra < cubes < rods. Bulk sulfites are also formed during SO2 adsorption on reduced CeO2 rods. The formation of surface sulfites and sulfates on CeO2 cubes is in good agreement with our DFT results of SO2 interactions with the CeO2(100) surface. CeO2 rods desorb SO2 at higher temperatures than cubes and octahedra nanocrystals, but bulk sulfates are formed on CeO2 rods and cubes after high-temperature desorption whereas only some surface sulfates/sulfites are left on octahedra. This difference is rationalized by the fact that CeO2 rods have the highest surface basicity and largest amount of defects among the three nanocrystals, so they bind and react with SO2 strongly and are the most degraded after SO2 adsorption cycles. The fundamental understanding obtained in this work on the effects of the surface structure and defects on the interaction of SO2 with CeO2 provides insights for the design of more sulfur-resistant CeO2-based catalysts.

  8. Quality-controlled small-scale production of a well-defined bacteriophage cocktail for use in human clinical trials.

    Directory of Open Access Journals (Sweden)

    Maya Merabishvili

    Full Text Available We describe the small-scale, laboratory-based, production and quality control of a cocktail, consisting of exclusively lytic bacteriophages, designed for the treatment of Pseudomonas aeruginosa and Staphylococcus aureus infections in burn wound patients. Based on successive selection rounds three bacteriophages were retained from an initial pool of 82 P. aeruginosa and 8 S. aureus bacteriophages, specific for prevalent P. aeruginosa and S. aureus strains in the Burn Centre of the Queen Astrid Military Hospital in Brussels, Belgium. This cocktail, consisting of P. aeruginosa phages 14/1 (Myoviridae and PNM (Podoviridae and S. aureus phage ISP (Myoviridae was produced and purified of endotoxin. Quality control included Stability (shelf life, determination of pyrogenicity, sterility and cytotoxicity, confirmation of the absence of temperate bacteriophages and transmission electron microscopy-based confirmation of the presence of the expected virion morphologic particles as well as of their specific interaction with the target bacteria. Bacteriophage genome and proteome analysis confirmed the lytic nature of the bacteriophages, the absence of toxin-coding genes and showed that the selected phages 14/1, PNM and ISP are close relatives of respectively F8, phiKMV and phage G1. The bacteriophage cocktail is currently being evaluated in a pilot clinical study cleared by a leading Medical Ethical Committee.

  9. Soft chemistry routes for synthesis of rare earth oxide nanoparticles with well defined morphological and structural characteristics

    Science.gov (United States)

    Mancic, L.; Marinkovic, B. A.; Marinkovic, K.; Dramicanin, M.; Milosevic, O.

    2011-11-01

    Phosphors of (Y0.75Gd0.25)2O3:Eu3+ (5 at.%) have been prepared through soft chemistry routes. Conversion of the starting nitrates mixture into oxide is performed through two approaches: (a) hydrothermal treatment (HT) at 200 °C/3 h of an ammonium hydrogen carbonate precipitated mixture and (b) by thermally decomposition of pure nitrate precursor solution at 900 °C in dispersed phase (aerosol) within a tubular flow reactor by spray pyrolysis process (SP). The powders are additionally thermally treated at different temperatures: 600, 1000, and 1100 °C for either 3 or 12 h. HT—derived particles present exclusively one-dimensional morphology (nanorods) up to the temperatures of 600 °C, while the leaf-like particles start to grow afterward. SP—derived particles maintain their spherical shape up to the temperatures of 1100 °C. These submicron sized spheres were actually composed of randomly aggregated nanoparticles. All powders exhibits cubic Ia- 3 structure (Y0.75Gd0.25)2O3:Eu and have improved optical characteristics due to their nanocrystalline nature. The detailed study of the influence of structural and morphological powder characteristics on their emission properties is performed based on the results of X-ray powder diffractometry, scanning electron microscopy, X-ray energy dispersive spectroscopy, transmission electron microscopy, and photoluminescence measurements.

  10. Physical Demands Study - Focus Groups

    Science.gov (United States)

    2015-10-26

    and the rounds in the boxes weigh 35 lb, which is lighter than equipment handled in the other physically demanding job tasks already identified...and standards. Ergonomics . 53: 858-871. 40 Appendix A: Questionnaires Completed by Volunteers prior to each Focus Group Interview 1 2 3 4a 4b 5

  11. A new approach for the preparation of well-defined Rh and Pt nanoparticles stabilized by phosphine-functionalized silica for selective hydrogenation reactions.

    Science.gov (United States)

    Llop Castelbou, J; Szeto, K C; Barakat, W; Merle, N; Godard, C; Taoufik, M; Claver, C

    2017-03-18

    In this work, a new methodology for the synthesis of well-defined metallic nanoparticles supported on silica is described. This methodology is based on the surface control provided by SOMC. The nanoparticles are formed via the organometallic approach and are catalytically active in the hydrogenation of p-xylene, 3-hexyne, 4-phenyl-2 butanone, benzaldehyde, and furfural.

  12. A well-defined silica-supported aluminium alkyl through an unprecedented, consecutive two-step protonolysis–alkyl transfer mechanism

    KAUST Repository

    Pelletier, Jérémie

    2011-01-01

    Impregnation of [(AliBu3)(Et2O)] on partially dehydroxylated SBA-15 affords a mesoporous material bearing the well-defined single site surface aluminium species [(≡SiO)2Al(iBu)(Et 2O)]. © The Royal Society of Chemistry.

  13. Utilization of Skills in the Care of the Patient with Common, Well-Defined Health Deviations I (NS 217): Competency-Based Course Syllabus.

    Science.gov (United States)

    Green, Elizabeth G.; Yates, Laura H.

    "Utilization of Skills in the Care of the Patient with Common, Well-Defined Health Deviations I" (NS 217) is an associate degree nursing course offered at Chattanooga State Technical Community College to help students develop new competencies necessary for the care of patients with deviations of the cardiovascular, endocrine, integumentary, and…

  14. Generation of Well-Defined Pairs of Silylamine on Highly Dehydroxylated SBA-15: Application to the Surface Organometallic Chemistry of Zirconium

    KAUST Repository

    Azzi, Joachim

    2012-11-01

    Design of a new well-defined surface organometallic species [O-(=Si–NH)2Zr(IV)Np2] has been obtained by reaction of tetraneopentyl zirconium (ZrNp4) on SBA-15 surface displaying mainly silylamine pairs [O-(=Si–NH2)2]. These surface species have been achieved by an ammonia treatment of a highly dehydroxylated SBA-15 at 1000°C (SBA-151000). This support is known to contain mainly strained reactive siloxane bridges (≡Si-O-Si≡)[1] along with a small amount of isolated plus germinal silanols =Si(OH)2. Chemisorption of ammonia occurs primarily by opening these siloxane bridges[2] to generate silanol/silylamine pairs [O-(=Si–NH2)(=SiOH)] followed by substitution of the remaining silanol. Further treatment using hexamethyldisilazane (HMDS) results in the protection of the isolated remaining silanol groups by formation of ≡Si-O-SiMe3 and =Si(OSiMe3)2 but leaves ≡SiNH2 untouched. After reaction of this functionalized surface with ZrNp4, this latter displays mainly a bi-podal zirconium neopentyl organometallic complex [O-(=Si–NH)2Zr(IV)Np2] which has been fully characterized by diverse methods such as infrared transmission spectroscopy, magic angle spinning solid state nuclear magnetic resonance, surface elemental analysis, small angle X-ray powder diffraction (XRD), nitrogen adsorption and energy filtered transmission electron microscopy (EFTEM). These different characterization tools unambiguously prove that the zirconium organometallic complex reacts mostly with silylamine pairs to give a bi-podal zirconium bis-neopentyl complex, uniformly distributed into the channels of SBA-151000. Therefore this new material opens a new promising research area in Surface Organometallic Chemistry which, so far, was dealing mainly with O containing surface. It is expected that vicinal amine functions may play a very different role as compared with classical inorganic supports. Given the importance in the last decades of N containing ligands in catalysis, one may expect

  15. Micro Sourcing Strategic Framework for Low Income Group

    National Research Council Canada - National Science Library

    Noor Habibah Arshad; Siti Salwa Salleh; Syaripah Ruzaini Syed Aris; Norjansalika Janom; Norazam Mastuki

    2013-01-01

    .... These micro tasks are well-defined and then distributed to a group of workers. The objective of this study is to develop the strategic framework of micro sourcing to generate income for the low income group...

  16. The Iraq Study Group Report

    Science.gov (United States)

    2006-12-01

    Hilda Arellano —U.S. Agency for International Development Director in Iraq * Terrance Kelly—Director, Office of Strategic Plans and Assessments...President, Mercy Corps Michael O’Hanlon—Senior Fellow, Foreign Policy Studies, The Brookings Institution George Packer—The New Yorker Carlos Pascual—Vice

  17. Electronic Effects of Aluminum Complexes in the Copolymerization of Propylene Oxide with Tricyclic Anhydrides: Access to Well-Defined, Functionalizable Aliphatic Polyesters.

    Science.gov (United States)

    Van Zee, Nathan J; Sanford, Maria J; Coates, Geoffrey W

    2016-03-02

    The synthesis of well-defined and functionalizable aliphatic polyesters remains a key challenge in the advancement of emerging drug delivery and self-assembly technologies. Herein, we investigate the factors that influence the rates of undesirable transesterification and epimerization side reactions at high conversion in the copolymerization of tricyclic anhydrides with excess propylene oxide using aluminum salen catalysts. The structure of the tricyclic anhydride, the molar ratio of the aluminum catalyst to the nucleophilic cocatalyst, and the Lewis acidity of the aluminum catalyst all influence the rates of these side reactions. Optimal catalytic activity and selectivity against these side reactions requires a careful balance of all these factors. Effective suppression of undesirable transesterification and epimerization was achieved even with sterically unhindered monomers using a fluorinated aluminum salph complex with a substoichiometric amount of a nucleophilic cocatalyst. This process can be used to synthesize well-defined block copolymers via a sequential addition strategy.

  18. Counterions control whether self-assembly leads to formation of stable and well-defined unilamellar nanotubes or nanoribbons and nanorods

    DEFF Research Database (Denmark)

    Shi, Dong; Schwall, Christian; Sfintes, George

    2014-01-01

    Self-assembly of the amphiphilic π-conjugated carbenium ion ATOTA-1(+) in aqueous solution selectively leads to discrete and highly stable nanotubes or nanoribbons and nanorods, depending on the nature of the counterion (Cl(-) vs. PF6(-), respectively). The nanotubes formed by the Cl(-) salt...... illustrate an exceptional example of a structural well-defined (29±2 nm in outer diameter) unilamellar tubular morphology featuring π-conjugated functionality and high stability and flexibility, in aqueous solution....

  19. Hydro-Metathesis of Long-Chain Olefin (1-decene) using Well-Defined Silica-Supported Tungsten (VI), Molybdenum (VI) and Tantalum (V) Catalysts

    KAUST Repository

    Saidi, Aya

    2016-11-01

    Nowadays, catalysis lies at the heart of economy growth mainly in the petroleum industry. Catalysis can offer real and potential solutions to the current challenges for a long-term sustainable energy, green chemistry, and environmental protection. In this context, one of the most important and future prosperity promising catalytic applications in the petrochemical field is hydrocarbons metathesis; it consists on the conversion of both renewable and non-petroleum fossil carbon sources to transportation fuels. Olefin metathesis has become one of the standard methodologies for constructing C-C bonds in many organic transformation reactions. This owed to the numerous types of metathesis reactions that have been developed, for example, enyne, ring-opening and closing, self and cross metathesis, etc. But the one step conversion of olefin to alkanes has not been studied much. Recently, only one such a work has been published for the hydro-metathesis of propylene by tantalum hydride supported on KCC-1 in dynamic reactor. With this knowledge, we thought to study the hydro-metathesis using liquid olefin (1-decene). Another aspect of using 1-decene comes from our previous experience on metathesis of n-decane where the first step is the conversion of decane to 1-decene and subsequently to different chain length alkanes with W-alkyl/alkylidene catalyst. In this way, it would be easy for us to use different catalysts and compare them with parent catalyst concerning TON. We found 100% conversion with TON of 1010 using supported WMe6 onto SiO2-700 [(≡Si-O-)WMe5] against the previous results for n-decane showing 20% conversion and TON of 153. In this work, we disclose the hydro-metathesis reaction of 1-decene using well-defined silica supported W(VI), Mo(VI) and Ta(V) alkyl catalysts in batch reactor condition. This work is divided into three major sections; first chapter contains an introduction to the field of catalysis and surface organometallic chemistry. In second chapter

  20. Unearthing a Well-Defined Highly Active Bimetallic W/Ti Precatalyst Anchored on a Single Silica Surface for Metathesis of Propane

    KAUST Repository

    Samantaray, Manoja

    2017-02-10

    Two compatible organometallic complexes, W(Me)(6) (1) and TiNp4 (2), were successively anchored on a highly dehydroxylated single silica support (SiO2-700) to synthesize the well-defined bimetallic precatalyst [(equivalent to Si-O-)W(Me)(5)(equivalent to Si-O-)Ti(Np)(3)] (4). Precatalyst 4 was characterized at the molecular level using advanced surface organometallic chemistry (SOMC) characterization techniques. The strong autocorrelation observed between methyl of W and Ti in H-1-H-1 multiple-quantum NMR spectra demonstrates that W and Ti species are in close proximity to each other. The bimetallic precatalyst 4, with a turnover number (TON) of 9784, proved to be significantly more efficient than the silica-supported monometallic catalyst [(equivalent to Si-O-)W(Me)(5)] (3), with a TON of 98, for propane metathesis at 150 degrees C in a flow reactor. The dramatic improvement in the activity signifies the cooperativity between Ti and W and indicates that the key step of alkane metathesis (C-H bond activation followed by beta-H elimination) occurs on Ti, followed by olefin metathesis, which occurs on W. We have demonstrated the influence and importance of proximity of Ti to W for achieving such a significantly high activity. This is the first report demonstrating the considerably high activity (TON = 9784) in propane metathesis at moderate temperature (150 degrees C) using a well-defined bimetallic system prepared via the SOMC approach.

  1. Tailor-made starch-based conjugates containing well-defined poly(vinyl acetate and its derivative poly(vinyl alcohol

    Directory of Open Access Journals (Sweden)

    2011-06-01

    Full Text Available Reversible addition-fragmentation chain transfer (RAFT polymerization was adopted to synthesize starch-based conjugates that possessed controllable architecture and properties. Starch-based xanthate agent was prepared and applied as chain transfer agent to conduct the living/controlled polymerization (LCP of vinyl acetate, which generated tailor-made conjugates of starch and well-defined poly(vinyl acetate (SVAc. The relevant derivatives, conjugates of starch and chain length-controlled poly(vinyl alcohol (SVA, were obtained subsequently. Various characterizations such as Fourier transform infrared spectra (FTIR, ultraviolet-visible spectroscopy (UV, proton nuclear magnetic resonance (1H NMR, gel permeation chromatography (GPC, X-ray diffraction (XRD, Thermogravimetric analysis (TGA, and dynamic mechanical thermal analysis (DMTA were performed to examine the structure of intermediates and the starch-based conjugates. Static contact angle measurements revealed that the hydrophilic character of starch-based conjugates was tunable. Well-defined SVAc was amphiphilic and it was able to self-assemble into size controllable micelles, which was verified by contact angles, transmission electron microscopy (TEM and dynamic light scattering (DLS tests. SVA exhibited much higher capability to form physically cross-linked hydrogel than starch did. Both the characteristic of SVAc and SVA were chain length-dependent.

  2. Química organometálica de superfície aplicada à preparação de catalisadores heterogêneos bem definidos Surface organometallic chemistry applied to the preparation of well defined heterogeneous catalysts

    Directory of Open Access Journals (Sweden)

    Silvana I. Wolke

    2002-11-01

    Full Text Available The study of the reactions of organometallic complexes with the surfaces of inorganic oxides, zeolites and metals constitutes the basis of Surface Organometallic Chemistry (SOMC. The basic rules of organometallic chemistry are often valid when applied to surfaces and well-defined surface organometallic complexes can be obtained. These complexes can be used as heterogeneous catalysts or, by controlled reactions, can be transformed in other species useful for a given catalytic reaction. In some cases, these catalysts exhibit higher activity and/or selectivity than their analogous molecular complexes.

  3. Membranes with well-defined ions transport channels fabricated via solvent-responsive layer-by-layer assembly method for vanadium flow battery.

    Science.gov (United States)

    Xu, Wanxing; Li, Xianfeng; Cao, Jingyu; Zhang, Hongzhang; Zhang, Huamin

    2014-02-06

    In this work we presented a general strategy for the fabrication of membranes with well-defined ions transport channels through solvent-responsive layer-by-layer assembly (SR-LBL). Multilayered poly (diallyldimethylammonium chloride) (PDDA) and poly (acrylic acid) (PAA) complexes were first introduced on the inner pore wall and the surface of sulfonated poly (ether ether ketone)/poly (ether sulfone) (PES/SPEEK) nanofiltration membranes to form ions transport channels with tuned radius. This type of membranes are highly efficient for the separators of batteries especially vanadium flow batteries (VFBs): the VFBs assembled with prepared membranes exhibit an outstanding performance in a wide current density range, which is much higher than that assembled with commercial Nafion 115 membranes. This idea could inspire the development of membranes for other flow battery systems, as well as create further progress in similar areas such as fuel cells, electro-dialysis, chlor-alkali cells, water electrolysis and so on.

  4. Synthesis of bis-peptides attached on poly[n]norbornene molecular scaffolds with well-defined relative positions and distances.

    Science.gov (United States)

    Shang, Muhong; Warrener, Ronald N; Butler, Douglas N; Murata, Yasujiro; Margetić, Davor

    2011-05-01

    This article describes novel synthetic approaches to polynorbornene molecular scaffolds substituted with peptides at various, well-defined positions. A library of norbornene building blocks with attached peptides was prepared. Alkene cyclobutane epoxide (ACE) coupling method was used as a key step reaction for the connection of two norbornene building blocks into bis-peptide scaffolds. Photodimerization of cyclobutene diesters offers an alternative route to polynorbornene bis-peptides. Pyrrolo-peptides were used for preparation of peptide-substituted 7-aza norbornenes. Asymmetrical bis-peptide scaffolds were prepared by ACE coupling of peptide-norbornane epoxide with another norbornene-peptide block. Chemical elaboration of bridgehead dimethyl esters of ACE products or epoxide ACE reagents was also used for peptide attachment.

  5. Well-Defined Degradable Cationic Polylactide as Nanocarrier for the Delivery of siRNA to Silence Angiogenesis in Prostate Cancer

    Science.gov (United States)

    Chen, Chih-Kuang; Law, Wing-Cheung; Aalinkeel, Ravikumar; Nair, Bindukumar; Kopwitthaya, Atcha; Mahajan, Supriya D.; Reynolds, Jessica L.; Zou, Jiong

    2013-01-01

    Well-defined tertiary amine-functionalized cationic polylactides (CPLAs) are synthesized by thiol-ene click functionalization of an allyl-functionalized polylactide, and utilized here for the delivery of interleukin-8 (IL-8) siRNA via CPLA-IL-8 siRNA nanoplexes. The CPLAs possess remarkable hydrolytic degradability, and their cytotoxicity is relatively low. The CPLA-IL-8 siRNA nanoplexes can be readily taken up by prostate cancer cells, resulting in significant IL-8 gene silencing. It is found that the degradability and cytotoxicity of CPLAs, as well as the transfection efficiency of the CPLA-IL-8 siRNA nanoplexes, positively correlate with the amine mol% of CPLAs. PMID:23184827

  6. The quality of control groups in nonrandomized studies published in the Journal of Hand Surgery.

    Science.gov (United States)

    Johnson, Shepard P; Malay, Sunitha; Chung, Kevin C

    2015-01-01

    To evaluate control group selection in nonrandomized studies published in the Journal of Hand Surgery American (JHS). We reviewed all papers published in JHS in 2013 to identify studies that used nonrandomized control groups. Data collected included type of study design and control group characteristics. We then appraised studies to determine whether authors discussed confounding and selection bias and how they controlled for confounding. Thirty-seven nonrandomized studies were published in JHS in 2013. The source of control was either the same institution as the study group, a different institution, a database, or not provided in the manuscript. Twenty-nine (78%) studies statistically compared key characteristics between control and study group. Confounding was controlled with matching, exclusion criteria, or regression analysis. Twenty-two (59%) papers explicitly discussed the threat of confounding and 18 (49%) identified sources of selection bias. In our review of nonrandomized studies published in JHS, papers had well-defined controls that were similar to the study group, allowing for reasonable comparisons. However, we identified substantial confounding and bias that were not addressed as explicit limitations, which might lead the reader to overestimate the scientific validity of the data. Incorporating a brief discussion of control group selection in scientific manuscripts should help readers interpret the study more appropriately. Authors, reviewers, and editors should strive to address this component of clinical importance. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  7. Facebook Groups as LMS: A Case Study

    Science.gov (United States)

    Meishar-Tal, Hagit; Kurtz, Gila; Pieterse, Efrat

    2012-01-01

    This paper describes a pilot study in using Facebook as an alternative to a learning management system (LMS). The paper reviews the current research on the use of Facebook in academia and analyzes the differences between a Facebook group and a regular LMS. The paper reports on a precedent-setting attempt to use a Facebook group as a course…

  8. Facilitating peer learning in study groups

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine; Madsen, Lene Møller

    2009-01-01

    the preliminary results from the facilitated study groups. After one term (February-May), student satisfaction with both the social and the disciplinary environment had increased. The project shows how academic and social integration can be achieved with minimum faculty member involvement. This is done by relying...... 'Facilitating study environment' at one of DPU's educations in spring 2009. The pilot project consisted of three elements: Facilitated study groups, a student bar with facilitated activities, and academic identity events. Subsequently, we have studied students' experiences with the project. This paper outlines...... on the students' own resources, using peer-learning and facilitating these activities....

  9. Structural analysis and anticoagulant activities of the novel sulfated fucan possessing a regular well-defined repeating unit from sea cucumber.

    Science.gov (United States)

    Wu, Mingyi; Xu, Li; Zhao, Longyan; Xiao, Chuang; Gao, Na; Luo, Lan; Yang, Lian; Li, Zi; Chen, Lingyun; Zhao, Jinhua

    2015-04-13

    Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC-MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan) contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

  10. High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation.

    Science.gov (United States)

    Nomoto, Junichi; Makino, Hisao; Yamamoto, Tetsuya

    2016-12-01

    Five hundred-nanometer-thick ZnO-based textured polycrystalline films consisting of 490-nm-thick Al-doped ZnO (AZO) films deposited on 10-nm-thick Ga-doped ZnO (GZO) films exhibited a high Hall mobility (μ H) of 50.1 cm(2)/Vs with a carrier concentration (N) of 2.55 × 10(20) cm(-3). Firstly, the GZO films were prepared on glass substrates by ion plating with dc arc discharge, and the AZO films were then deposited on the GZO films by direct current magnetron sputtering (DC-MS). The GZO interface layers with a preferential c-axis orientation play a critical role in producing AZO films with texture development of a well-defined (0001) orientation, whereas 500-nm-thick AZO films deposited by only DC-MS showed a mixture of the c-plane and the other plane orientation, to exhibit a μ H of 38.7 cm(2)/Vs with an N of 2.22 × 10(20) cm(-3).

  11. Structural Analysis and Anticoagulant Activities of the Novel Sulfated Fucan Possessing a Regular Well-Defined Repeating Unit from Sea Cucumber

    Directory of Open Access Journals (Sweden)

    Mingyi Wu

    2015-04-01

    Full Text Available Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC–MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2 and (1→3-linked tetrasaccharide repeating units. Approximately 50% of the units from L. grisea (100% for H. edulis fucan contain sides of oligosaccharides formed by nonsulfated fucose units linked to the O-4 position of the central core. Anticoagulant activity assays indicate that the sea cucumber fucans strongly inhibit human blood clotting through the intrinsic pathways of the coagulation cascade. Moreover, the mechanism of anticoagulant action of the fucans is selective inhibition of thrombin activity by heparin cofactor II. The distinctive tetrasaccharide repeating units contribute to the anticoagulant action. Additionally, unlike the fucans from marine alga, although the sea cucumber fucans have great molecular weights and affluent sulfates, they do not induce platelet aggregation. Overall, our results may be helpful in understanding the structure-function relationships of the well-defined polysaccharides from invertebrate as new types of safer anticoagulants.

  12. Synthesis of well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization

    Science.gov (United States)

    Chen, Jiucun; Hu, Min; Zhu, Wendong; Li, Yaping

    2011-05-01

    We report on the synthesis of the well-defined structurally silica-nonlinear polymer core-shell nanoparticles via the surface-initiated atom transfer radical polymerization. At first, 3-(2-bromoisobutyramido)propyl(triethoxy)-silane (the ATRP initiator) was prepared by the reaction of 3-aminopropyltriethoxysilane with 2-bromoisobutyryl bromide. The ATRP initiator was covalently attached onto the nanosilica surface. The subsequent ATRP of HEMA from the initiator-attached SiO 2 surface was carried out in order to afforded functional nanoparticles bearing a hydroxyl moiety at the chain end, SiO 2-g-PHEMA-Br. The esterification reaction of pendent hydroxyl moieties of PHEMA segment with 2-bromoisobutyryl bromide afforded the SiO 2-based multifunctional initiator, SiO 2-g-PHEMA(-Br)-Br, bearing one bromine moiety on each monomer repeating unit within the PHEMA segment. Finally, the synthesis of SiO 2-g-PHEMA(-g-PSt)-b-PSt was accomplished by the ATRP of St monomer using SiO 2-g-PHEMA(-Br)-Br as multifunctional initiator. These organic/inorganic hybrid materials have been extensively characterized by FT-IR, XPS, TG, and TEM.

  13. High-Hall-Mobility Al-Doped ZnO Films Having Textured Polycrystalline Structure with a Well-Defined (0001) Orientation

    Science.gov (United States)

    Nomoto, Junichi; Makino, Hisao; Yamamoto, Tetsuya

    2016-06-01

    Five hundred-nanometer-thick ZnO-based textured polycrystalline films consisting of 490-nm-thick Al-doped ZnO (AZO) films deposited on 10-nm-thick Ga-doped ZnO (GZO) films exhibited a high Hall mobility ( μ H) of 50.1 cm2/Vs with a carrier concentration ( N) of 2.55 × 1020 cm-3. Firstly, the GZO films were prepared on glass substrates by ion plating with dc arc discharge, and the AZO films were then deposited on the GZO films by direct current magnetron sputtering (DC-MS). The GZO interface layers with a preferential c-axis orientation play a critical role in producing AZO films with texture development of a well-defined (0001) orientation, whereas 500-nm-thick AZO films deposited by only DC-MS showed a mixture of the c-plane and the other plane orientation, to exhibit a μ H of 38.7 cm2/Vs with an N of 2.22 × 1020 cm-3.

  14. 电位控制的固液界面有序纳米结构%Well defined nanostructures at solid /liquid interface under potential control

    Institute of Scientific and Technical Information of China (English)

    王栋; 万立骏; 白春礼

    2002-01-01

    The well defined nanostructures can be constructed at solid/liquid interface under potential control with ions, organic molecules or other objects. The molecule orientation and structure can be controlled by applying an electrode potential in electrolyte solution and the formation process can be monitored by electrochemical scanning tunneling microscopy. The so constructed nanostructure is potentially useful in future nano electronic devices fabrication.%在电极电势控制下,用原子、离子和有机分子在固液界面构筑了有序的纳米结构.利用电化学扫描隧道显微镜能够观察纳米结构的形成过程及电势控制下的结构转变和分子位相变化.这些纳米结构在未来的纳米电子器件的制造等领域有重要的应用价值.

  15. A Two-Component Adhesive: Tau Fibrils Arise from a Combination of a Well-Defined Motif and Conformationally Flexible Interactions.

    Science.gov (United States)

    Xiang, Shengqi; Kulminskaya, Natalia; Habenstein, Birgit; Biernat, Jacek; Tepper, Katharina; Paulat, Maria; Griesinger, Christian; Becker, Stefan; Lange, Adam; Mandelkow, Eckhard; Linser, Rasmus

    2017-02-22

    Fibrillar aggregates of Aβ and Tau in the brain are the major hallmarks of Alzheimer's disease. Most Tau fibers have a twisted appearance, but the twist can be variable and even absent. This ambiguity, which has also been associated with different phenotypes of tauopathies, has led to controversial assumptions about fibril constitution, and it is unclear to-date what the molecular causes of this polymorphism are. To tackle this question, we used solid-state NMR strategies providing assignments of non-seeded three-repeat-domain Tau(3RD) with an inherent heterogeneity. This is in contrast to the general approach to characterize the most homogeneous preparations by construct truncation or intricate seeding protocols. Here, carbon and nitrogen chemical-shift conservation between fibrils revealed invariable secondary-structure properties, however, with inter-monomer interactions variable among samples. Residues with variable amide shifts are localized mostly to N- and C-terminal regions within the rigid beta structure in the repeat region of Tau(3RD). By contrast, the hexapeptide motif in repeat R3, a crucial motif for fibril formation, shows strikingly low variability of all NMR parameters: Starting as a nucleation site for monomer-monomer contacts, this six-residue sequence element also turns into a well-defined structural element upon fibril formation. Given the absence of external causes in vitro, the interplay of structurally differently conserved elements in this protein likely reflects an intrinsic property of Tau fibrils.

  16. Electrically templated dewetting of a UV-curable prepolymer film for the fabrication of a concave microlens array with well-defined curvature.

    Science.gov (United States)

    Li, Xiangming; Tian, Hongmiao; Ding, Yucheng; Shao, Jinyou; Wei, Yuping

    2013-10-23

    This paper presents an economic method, based on electrically templated dewetting of a UV-curable prepolymer, for fabricating a concave microlens array (MLA) of high quality and high density. In our strategy, a voltage is applied to an electrode pair consisting of a conductive substrate coated with a UV-curable prepolymer film and a microhole-arrayed silicon template, sandwiching an air gap, to dewet the prepolymer film into a curved air-liquid interface. At or beyond a critical voltage, the curved prepolymer can be pulled quickly into contact with the protrusive underside of the silicon template. Contact of the prepolymer with the template can be detected by monitoring the leaky current in the polymer, followed by a UV curing of the prepolymer. Finally, by separating the mold from the solidified polymer, a concave MLA is obtained. The curvature of the MLA can be well-defined simply by changing the air gap between the mold and prepolymer film. Besides, the dewetting strategy results in a much smaller adhesion area between the mold and solidified polymer structures, which allows for easy separation of the mold from the MLA in a large-area operation.

  17. Structure-interfacial properties relationship and quantification of the amphiphilicity of well-defined ionic and non-ionic surfactants using the PIT-slope method.

    Science.gov (United States)

    Ontiveros, Jesús F; Pierlot, Christel; Catté, Marianne; Molinier, Valérie; Salager, Jean-Louis; Aubry, Jean-Marie

    2015-06-15

    The Phase Inversion Temperature of a reference C10E4/n-Octane/Water system exhibits a quasi-linear variation versus the mole fraction of a second surfactant S2 added in the mixture. This variation was recently proposed as a classification tool to quantify the Hydrophilic-Lipophilic Balance (HLB) of commercial surfactants. The feasibility of the so-called PIT-slope method for a wide range of well-defined non-ionic and ionic surfactants is investigated. The comparison of various surfactants having the same dodecyl chain tail allows to rank the polar head hydrophilicity as: SO3Na⩾SO4Na⩾NMe3Br>E2SO3Na≈CO2Na⩾E1SO3Na⩾PhSO3Na>Isosorbide(exo)SO4Na≫IsosorbideendoSO4Na≫E8⩾NMe2O>E7>E6⩾Glucosyl>E5⩾Diglyceryl⩾E4>E3>E2≈Isosorbide(exo)>Glyceryl>Isosorbide(endo). The influence on the surfactant HLB of other structural parameters, i.e. hydrophobic chain length, unsaturation, replacement of Na(+) by K(+) counterion, and isomerism is also investigated. Finally, the method is successfully used to predict the optimal formulation of a new bio-based surfactant, 1-O-dodecyldiglycerol, when performing an oil scan at 25 °C.

  18. A Well-Defined Silicon Nanocone-Carbon Structure for Demonstrating Exclusive Influences of Carbon Coating on Silicon Anode of Lithium-Ion Batteries.

    Science.gov (United States)

    Wang, Chao; Luo, Fei; Lu, Hao; Rong, Xiaohui; Liu, Bonan; Chu, Geng; Sun, Yu; Quan, Baogang; Zheng, Jieyun; Li, Junjie; Gu, Changzhi; Qiu, Xinping; Li, Hong; Chen, Liquan

    2017-01-25

    Nanotechnology and carbon coating have been applied to silicon anodes to achieve excellent lithium-ion batteries, but the exclusive influence of carbon coating on solid-electrolyte interphase (SEI) formation is difficult to exhibit distinctly because of the impurity and morphological irregularity of most nanostructured anodes. Here, we design a silicon nanocone-carbon (SNC-C) composite structure as a model anode to demonstrate the significant influences of carbon coating on SEI formation and electrochemical performance, unaffectedly as a result of pure electrode component and distinctly due to regular nanocone morphology. As demonstrated by morphological and elemental analysis, compared to the SNC electrode, the SNC-C electrode maintains a thinner SEI layer (∼10 nm) and more stable structure during cycling as well as longer cycle life (>725 cycles), higher Coulombic efficiency (>99%), and lower electrode polarization. This well-defined structure clearly shows the interface stability attributed to carbon coating and is promising in fundamental research of the silicon anode.

  19. Space Station concept development group studies

    Science.gov (United States)

    Powell, L. E.

    1984-01-01

    The NASA study activities in preparation for a Space Station began in the early 1970's. The early studies included many in-house NASA and contracted studies. A group of representatives from all the NASA Centers, titled the Space Station Concept Development Group (CDG) was involved in the studies which led to the initiation of the Space Station Program. The CDG studies were performed over a period of approximately one year and consisted of four phases. The initial phase had the objective to determine the functions required of the station as opposed to a configuration. The activities of the second phase were primarily concerned with a sizing of the facilities required for payloads and the resources necessary to support these mission payloads. The third phase of studies was designed to develop a philosophical approach to a number of areas related to autonomy, maintainability, operations and logistics, and verification. The fourth phase of the study was to be concerned with configuration assessment activities.

  20. Controllable assembly of well-defined monodisperse Au nanoparticles on hierarchical ZnO microspheres for enhanced visible-light-driven photocatalytic and antibacterial activity

    Science.gov (United States)

    Wang, Yuan; Fang, Hua-Bin; Zheng, Yan-Zhen; Ye, Rongqin; Tao, Xia; Chen, Jian-Feng

    2015-11-01

    A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of the ZMS/Au composites as well as the reproducibility and controllability of the entire assembly process. Results on the photoelectrochemical performance characterized by EIS and transient photocurrent response spectra indicate that the ZMS/Au composites possess increased photoinduced charge separation and transfer efficiency compared to the pure ZMS film. As a result, the hybrid composites exhibited enhanced decomposition activity for methylene blue and salicylic acid as well as antibacterial activity in killing S. aureus and E. coli under visible light irradiation. It can be noted that well-distributed Au components even at a rather low Au/ZnO weight ratio of ~1.2% also exhibited extraordinary photocatalysis. Such a facile and controllable self-assembly approach may be viable for preparing high-performance visible-light-driven ZMS/Au photocatalysts in a simple and controllable way, and consequently, the technology may extend to other plasmon-enhanced heterostructures made of nanostructured semiconductors and noble metals for great potential application in environmental protection.A high-efficiency visible-light-driven photocatalyst composed of homogeneously distributed Au nanoparticles (AuNPs) well-defined on hierarchical ZnO microspheres (ZMS) via a controllable layer-by-layer self-assembly technique is demonstrated. The gradual growth of the characteristic absorption bands of Au loaded on ZnO in the visible light region with an increasing number of assemblies indicates the enhancement of the light harvesting ability of

  1. On-line optical and X-ray spectroscopies with crystallography: an integrated approach for determining metalloprotein structures in functionally well defined states.

    Science.gov (United States)

    Ellis, Mark J; Buffey, Steven G; Hough, Michael A; Hasnain, S Samar

    2008-09-01

    X-ray-induced redox changes can lead to incorrect assignments of the functional states of metals in metalloprotein crystals. The need for on-line monitoring of the status of metal ions (and other chromophores) during protein crystallography experiments is of growing importance with the use of intense synchrotron X-ray beams. Significant efforts are therefore being made worldwide to combine different spectroscopies in parallel with X-ray crystallographic data collection. Here the implementation and utilization of optical and X-ray absorption spectroscopies on the modern macromolecular crystallography (MX) beamline 10, at the SRS, Daresbury Laboratory, is described. This beamline is equipped with a dedicated monolithic energy-dispersive X-ray fluorescence detector, allowing X-ray absorption spectroscopy (XAS) measurements to be made in situ on the same crystal used to record the diffraction data. In addition, an optical microspectrophotometer has been incorporated on the beamline, thus facilitating combined MX, XAS and optical spectroscopic measurements. By uniting these techniques it is also possible to monitor the status of optically active and optically silent metal centres present in a crystal at the same time. This unique capability has been applied to observe the results of crystallographic data collection on crystals of nitrite reductase from Alcaligenes xylosoxidans, which contains both type-1 and type-2 Cu centres. It is found that the type-1 Cu centre photoreduces quickly, resulting in the loss of the 595 nm peak in the optical spectrum, while the type-2 Cu centre remains in the oxidized state over a much longer time period, for which independent confirmation is provided by XAS data as this centre has an optical spectrum which is barely detectable using microspectrophotometry. This example clearly demonstrates the importance of using two on-line methods, spectroscopy and XAS, for identifying well defined redox states of metalloproteins during

  2. A-Well defined raw material specifications of product and its components, a key of successful new product design. A critical evaluation by case study

    Directory of Open Access Journals (Sweden)

    Vidyadhar Malhar Dandge

    2015-12-01

    Full Text Available New product design and development indeed needs long termvision for better product life and hence to have better product features the design team has to take into consideration various techno-commercial aspects todesign and develop most adequate new product. Normally in case of new product design all related activities are initiated by the team of technicians under the directive jointly given by top and marketing management of the concerned organization. Due to global competition in the market the product requirements are needed to be carefully identified so as to make the product more user friendly to the customers. Considering this it is quite obvious that top priority is for product performance considerations at the same time they have to establish the product cost to make it more competent in the market. Due to these constraints recently the design and development function has no more remained the responsibility technocrats but it has become techno-commercial activity. One should treat this as design and development joint activity to be performed by the dedicated team of techno-commercial people who are well equipped with sound technical knowledge so as to design the best possible product. Due to this reason the primary design activity is seen to be interfacing with various departments such as Marketing, Materials, Tool room ,Manufacturing, Vendor development and many other related departments and valuable in puts from them are badly needed at the initial phase of product design and development. This helps in identifying the product needs at various manufacturing stages well in advance. This ultimately helps the design department to deliver the most adequate product with no operational problems and product is ready to satisfy customer’s needs which ultimately leads to growth of organization through smooth product life cycle management.

  3. Electron exchange between r-keggin tungstoaluminates and a well-defined cluster-anion probe for studies in electron transfer

    Science.gov (United States)

    Yurii V. Geletii; Craig L. Hill; Alan J. Bailey; Kenneth I. Hardcastle; Rajai H. Atalla; Ira A. Weinstock

    2005-01-01

    Fully oxidized [alpha]-AlIIIW12O405-(1ox), and one-electron-reduced [alpha]-AlIIIW12O406-(1red), are well-behaved (stable and free of ion pairing) over a wide range of pH and ionic-strength values at room temperature in water. Having established this, 27Al NMR spectroscopy is used to measure rates of electron exchange between 1ox (27Al NMR: 72.2 ppm relative to Al(H2O)...

  4. Metacognition and Group Differences: A Comparative Study

    Science.gov (United States)

    Al-Hilawani, Yasser A.

    2014-01-01

    In this study, metacognition refers to performing visual analysis and discrimination of real life events and situations in naïve psychology, naïve physics, and naïve biology domains. It is used, along with measuring reaction time, to examine differences in the ability of four groups of students to select appropriate pictures that correspond with…

  5. Report of the Public Cryptography Study Group.

    Science.gov (United States)

    American Council on Education, Washington, DC.

    Concerns of the National Security Agency (NSA) that information contained in some articles about cryptography in learned and professional journals and in monographs might be inimical to the national security are addressed. The Public Cryptography Study Group, with one dissenting opinion, recommends that a voluntary system of prior review of…

  6. Alkane metathesis with the tantalum methylidene [(≡SiO)Ta(=CH2)Me2]/[(≡SiO)2Ta(=CH2)Me] generated from well-defined surface organometallic complex [(≡SiO)TaVMe4

    KAUST Repository

    Chen, Yin

    2015-01-21

    By grafting TaMe5 on Aerosil700, a stable, well-defined, silica-supported tetramethyl tantalum(V) complex, [(≡SiO)TaMe4], is obtained on the silica surface. After thermal treatment at 150 °C, the complex is transformed into two surface tantalum methylidenes, [(≡SiO)2Ta(=CH2)Me] and [(≡SiO)Ta(=CH2)Me2], which are active in alkane metathesis and comparable to the previously reported [(≡SiO)2TaHx]. Here we present the first experimental study to isolate and identify a surface tantalum carbene as the intermediate in alkane metathesis. A systematic experimental study reveals a new reasonable pathway for this reaction.

  7. Video-Assisted Thoracic Surgery Study Group.

    Science.gov (United States)

    LoCicero, J

    1993-09-01

    Both patients and the medical profession are quick to embrace new technology, particularly when it may replace an existing surgical procedure. Unfortunately, the rapidity of acceptance is rarely associated with careful evaluation. Laparoscopy is a recent example of such widely embraced technology. Studies of laparoscopy that yielded good comparative data to more traditional methods were slow to accrue. This led to the exposure of its shortcomings through governmental reports and the lay press. To prevent this from happening in thoracoscopy, two types of studies are required so that valid conclusions about the new technology can be drawn. The first is an accounting of the new technology as procedures evolve around it. The data collected in such a study should contain basic information, including the indications for the procedure, how it was performed, procedure length, associated complications, and patient outcome. Such information provides a broad profile of the technology, emphasizing from the outset its potential strengths and weaknesses. The second type of study involves a more detailed concurrent comparison of the specific procedures utilizing this technology to the established traditional methods. Such randomized studies help to firmly establish through scientific process the place of the new technology. The Video-Assisted Thoracic Surgery Study Group was organized in early 1992 to address these concerns. From an initial four surgeons the group has grown to include more than 41 institutions. Currently the group is collecting data in a registry and has established three clinical trials to evaluate video-assisted thoracic surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Report of the special study group

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.H.

    1956-07-18

    The special study group was activated by a charter letter from Sub-Section Managers of Pile Technology on June 20, 1956. The principal objectives were: to collect the information which is presently available for new reactor design and to determine what information should be developed; to make a guess at pile variables; and to point out development programs which must be pursued to achieve a detailed design start in two years. The study was restricted to graphite moderated reactors with H{sub 2}0, D{sub 2}0, and organic coolants. The program was to determine technical feasibility only and detailed economic considerations were not to be included. This report presents the conclusions of the group and some of the reasoning behind these conclusions.

  9. Dual-mode fluorescence switching induced by self-assembly of well-defined poly(arylene ether sulfone)s containing pyrene and amide moieties.

    Science.gov (United States)

    Park, Jeyoung; Kim, Jisung; Seo, Myungeun; Lee, Jinhee; Kim, Sang Youl

    2012-11-04

    A new class of fluorescent organogelators, pyrene-containing poly(arylene ether sulfone)s, showed two fluorescence switching modes in different gelation solvents. The THF gel exhibited excimer emission due to dimerization of the pyrene groups. In contrast, excimer emission was quenched after gelation in MC because of stacking among the pyrene groups.

  10. Well-defined functional mesoporous silica/polymer hybrids prepared by an ICAR ATRP technique integrated with bio-inspired polydopamine chemistry for lithium isotope separation.

    Science.gov (United States)

    Liu, Yuekun; Liu, Xuegang; Ye, Gang; Song, Yang; Liu, Fei; Huo, Xiaomei; Chen, Jing

    2017-05-09

    Mesoporous silica/polymer hybrids with well-preserved mesoporosity were prepared by integrating the initiators for continuous activator regeneration (ICAR) atom transfer radical polymerization (ATRP) technique with the bio-inspired polydopamine (PDA) chemistry. By manipulating the auto-oxidative polymerization of dopamine, uniform PDA layers were deposited on the surfaces and pore walls of ordered mesoporous silicas (OMSs), thereby promoting the immobilization of ATRP initiators. Poly(glycidyl methacrylate) (PGMA) brushes were then grown from the OMSs by using the ICAR ATRP technique. The evolution of the mesoporous silica/polymer hybrids during synthesis, in terms of morphology, structure, surface and porous properties, was detailed. And, parameters influencing the controlled growth of polymer chains in the ICAR ATRP system were studied. Taking advantage of the abundant epoxy groups in the PGMA platform, post-functionalization of the mesoporous silica/polymer hybrids by the covalent attachment of macrocyclic ligands for the adsorptive separation of lithium isotopes was realized. Adsorption behavior of the functionalized hybrids toward lithium ions was fully investigated, highlighting the good selectivity, and effects of temperature, solvent and counter ions. The ability for lithium isotope separation was evaluated. A higher separation factor could be obtained in systems with softer counter anions and lower polarity solvents. More importantly, due to the versatility of the ICAR ATRP technique, combined with the non-surface specific PDA chemistry, the methodology established in this work would provide new opportunities for the preparation of advanced organic-inorganic porous hybrids for broadened applications.

  11. Environmental studies group. Annual report for 1978

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, D. C.; Hurley, J. D. [eds.

    1980-08-21

    Group projects included radioecological studies of aquatic and terrestrial systems, land management activities, foodstuff monitoring, dust transport studies including fugitive dust measurements and modeling, and several support programs involving evaluation of the plant's ambient air samplers and airborne tritium monitoring techniques. Some salient results from the several project reports include determination of an appropriate model for mechanically generated fugitive dust dispersion, a radionuclide inventory of Smart Ditch Pond (Pond D-1), a coefficient of community determination for two terrestrial sample plots on the plant site buffer zone, a natality and mortality rate determination for fawns in the plant deer herd (including one positive coyote-kill determination), inlet loss and filter paper collection efficiencies for the plant ambient air samplers, and differential tritium sampling measurements of the vapor in Building 771 stack effluent.

  12. Report of JLC site study group

    CERN Document Server

    Hasegawa, T; Yamashita, S

    2003-01-01

    This study group selected some good sites for construction of JLC (Electron-Positron Linear Collider) on the basis of investigation of data and field survey. The aims, activity, use of underground of private land, conditions of site, selection of site at present and future, summary and proposal are reported. 9 sites (Hidaka, Kitakami, Murayama, Abukuma, Kitaibaraki, Aichi and Gifu, Takamatsu, Hiroshima and Seburi range) are selected for the construction on the basis of firm ground and 4 sites (Okinawa, Harima, Tsukuba and Mutsuogawara) for development and researches. 9 sites area consists of plutonic rock or old strata of Paleozoic era. Many problems in each site are reported. There are three following proposals; 1) the self-governing communities of the sites have to understand JLC and start to construct it by information, 2) a site evaluation committee consists of specialist of civil engineering, building, social and natural environment and disaster prevention and 3) the vibration test should be carried out ...

  13. DPHEP: From Study Group to Collaboration

    CERN Document Server

    Shiers, Jamie

    2014-01-01

    The international study group on data preservation in High Energy Physics, DPHEP, achieved a major milestone in 2012 with the publication of its eagerly anticipated large-scale report [1]. This document contains a description of data preservation activities from all major high energy physics collider-based experiments and laboratories. A central message of the report is that data preservation in HEP is not possible without long term investment in not only hardware but also human resources, and with this in mind DPHEP will evolve to a new collaboration structure in 2013. This paper describes the progress made since the publication of that report – shortly before CHEP 2012 – as well as the future working directions of the new collaboration.

  14. Breast cancer in situ. From pre-malignant lesion of uncertain significance to well-defined non-invasive malignant lesion

    DEFF Research Database (Denmark)

    Laenkholm, Anne-Vibeke; Jensen, Maj-Britt; Kroman, Niels;

    2008-01-01

    In addition to nationwide standardized pathology forms for operable primary invasive breast cancer, the Danish Breast Cancer cooperative Group (DBCG) in 1982 introduced pathology forms for breast cancer in situ (CIS). The histological reporting form was used primarily for ductal cancer in situ...... the pleomorphic subtype of LCIS was added to histological subtypes. The present work reviews the DBCG guidelines and recommendations concerning CIS adding a brief characterization of the Danish CIS population. It also refers to the introduction of modern molecular pathology and distinction between low...

  15. Long-term changes in bone mass after partial gastrectomy in a well-defined population and its relation to tobacco and alcohol consumption

    DEFF Research Database (Denmark)

    Krogsgaard, M R; Frølich, A; Lund, B

    1995-01-01

    alcohol consumption or cumulative tobacco consumption and bone mineral content in each group. Gastrectomized women smoked much more than control women, and smoking may be a determinant factor for the bone loss, as it is in healthy persons. Operated patients had a lower intake of milk products. All...... patients were exposed to sunlight for more than 3 hours/week. It is suggested that osteopenia after gastrectomy might be caused by calcium depletion rather than lack of vitamin D. The consumption of tobacco but not of alcohol was connected to bone loss....

  16. Well-defined crystallites autoclaved from the nitrate/NH{sub 4}OH reaction system as the precursor for (Y,Eu){sub 2}O{sub 3} red phosphor: Crystallization mechanism, phase and morphology control, and luminescent property

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Qi [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Li Jiguang, E-mail: LI.Jiguang@nims.go.jp [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan); Ma, Renzhi; Sasaki, Takayoshi [World Premier International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Yang, Xiaojing [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Li Xiaodong; Sun Xudong [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Sakka, Yoshio [Advanced Materials Processing Unit, National Institute for Materials Science, Sengen 1-2-1, Tsukuba, Ibaraki 305-0047 (Japan)

    2012-08-15

    Autoclaving the rare-earth nitrate/NH{sub 4}OH reaction system under the mild conditions of 120-200 Degree-Sign C and pH 6-13 have yielded four types of well-crystallized compounds with their distinctive crystal shapes, including Ln{sub 2}(OH){sub 5}NO{sub 3}{center_dot}nH{sub 2}O (Ln=Y and Eu) layered rare-earth hydroxide (hexagonal platelets), Ln{sub 4}O(OH){sub 9}NO{sub 3} oxy-hydroxyl nitrate (hexagonal prisms and microwires), Ln(OH){sub 2.94}(NO{sub 3}){sub 0.06}{center_dot}nH{sub 2}O hydroxyl nitrate (square nanoplates), and Ln(OH){sub 3} hydroxide (spindle-shaped microrods). The occurrence domains of the compounds are defined. Ammonium nitrate (NH{sub 4}NO{sub 3}) as a mineralizer effectively widens the formation domains of the NO{sub 3}{sup -} containing compounds while leads to larger crystals at the same time (up to 0.3 mm). Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Optical properties (PLE/PL) of the four phases were characterized in detail and were interpreted from the different site symmetries of Eu{sup 3+}. The compounds convert to cubic-structured (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} by annealing at 600 Degree-Sign C while retaining their original crystal morphologies. The resultant phosphor oxides of diverse particle shapes exhibit differing optical properties, in terms of luminescent intensity, asymmetry factor of luminescence and fluorescence lifetime, and the underlying mechanism was discussed. - Graphical abstract: Well-defined crystallites of the various phases have been autoclaved from the nitrate/NH{sub 4}OH reaction system. Crystallization mechanisms of the compounds and the effects of NH{sub 4}NO{sub 3} were discussed. Highlights: Black-Right-Pointing-Pointer Well-defined crystallites of four phases have been hydrothermally synthesized. Black-Right-Pointing-Pointer The occurrence domains of the compounds are defined. Black-Right-Pointing-Pointer Crystallization mechanisms and the

  17. New Groups Study Science's Effect on Society

    Science.gov (United States)

    O'Sullivan, Dermot A.

    1973-01-01

    Describes the chief aims of the Council for Science and Society in London and the International Institute for Applied Systems Analysis in Vienna. Indicates that both groups are planning to function as a multinational interdisciplinary organization. (CC)

  18. Well-defined polyethylene-based graft terpolymers by combining nitroxide-mediated radical polymerization, polyhomologation and azide/alkyne “click” chemistry†

    KAUST Repository

    Alkayal, Nazeeha

    2016-03-30

    Novel well–defined polyethylene–based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” chemistry. Three steps were involved in this approach: (i) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using the PE-OH as macroinitiator, (ii) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (iii) “click” linking reaction to afford the PE-based graft terpolymers. All intermediates and final products were characterized by high-temperature size exclusion chromatography (HT-SEC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC).

  19. Controlled interactions between anhydrous keggin-type heteropolyacids and silica support: Preparation and characterization of well-defined silica-supported polyoxometalate species

    KAUST Repository

    Grinenval, Eva

    2010-11-11

    Anhydrous Keggin-type phosphorus heteropolyacids were deposited on partially dehydroxylated silica by using the surface organometallic chemistry (SOMC) strategy. The resulting solids were characterized by a combination of physicochemical methods including IR, Raman, 1D and 2D 1H, and 31P MAS NMR, electron microscopy experiments and density functional theory (DFT) calculations. It is shown that the main surface species is [ - Si(OH...H+)]2[H+]1[PM 12O403-] where the polyoxometalate is linked to the support by proton interaction with two silanols. Two other minor species (10% each) are formed by coordination of the polyoxometalate to the surface via the interaction between all three protons with three silanol groups or via three covalent bonds formed by dehydroxylation of the above species. Comparison of the reactivity of these solids and of compounds prepared by a classical way shows that the samples prepared by the SOMC approach contain ca. 7 times more acid sites. © 2010 American Chemical Society.

  20. Protein adsorption at polymer-grafted surfaces : Comparison between a mixture of saliva proteins and some well-defined model proteins

    NARCIS (Netherlands)

    Kawasaki, K; Kambara, M; Matsumura, H; Norde, W

    2003-01-01

    Grafting a dense layer of soluble polymers onto a surface is a well-established method for controlling protein adsorption. In the present study, polyethylene oxide (PEO) layers of three different grafting densities were prepared, i.e. 10-15 nm(2), 5.5 nm(2) and 4 nm(2) per polymer chain, respectivel

  1. Protein adsorption at polymer-grafted surfaces: Comparison between a mixture of saliva proteins and some well-defined model proteins

    NARCIS (Netherlands)

    Kawasaki, K.; Kambara, M.; Matsumura, H.; Norde, W.

    2003-01-01

    Grafting a dense layer of soluble polymers onto a surface is a well-established method for controlling protein adsorption. In the present study, polyethylene oxide (PEO) layers of three different grafting densities were prepared, i.e. 10-15 nm2, 5.5 nm2 and 4 nm2 per polymer chain, respectively. The

  2. Modular synthesis of glycopolymers with well-defined sugar units in the side chain via Ugi reaction and click chemistry : hetero vs. homo

    NARCIS (Netherlands)

    Xue, Lulu; Xiong, Xinhong; Chen, Kui; Luan, Yafei; Chen, Gaojian; Chen, Hong

    2016-01-01

    For synthetic glycopolymers, multivalent carbohydrate-protein interactions have been mostly studied in homoglycopolymers so far. However, natural oligosaccharides tend to consist of various sugars and this kind of heterogeneity is used to tune affinity and selectivity towards a specific receptor. He

  3. Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN(3) -Pincer Ligand.

    Science.gov (United States)

    Pan, Yupeng; Pan, Cheng-Ling; Zhang, Yufan; Li, Huaifeng; Min, Shixiong; Guo, Xunmun; Zheng, Bin; Chen, Hailong; Anders, Addison; Lai, Zhiping; Zheng, Junrong; Huang, Kuo-Wei

    2016-05-01

    An unsymmetrically protonated PN(3) -pincer complex in which ruthenium is coordinated by one nitrogen and two phosphorus atoms was employed for the selective generation of hydrogen from formic acid. Mechanistic studies suggest that the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved.

  4. The Autism Diagnostic Observation Schedule, Module 4: Application of the Revised Algorithms in an Independent, Well-Defined, Dutch Sample (N = 93)

    Science.gov (United States)

    de Bildt, Annelies; Sytema, Sjoerd; Meffert, Harma; Bastiaansen, Jojanneke A. C. J.

    2016-01-01

    This study examined the discriminative ability of the revised Autism Diagnostic Observation Schedule module 4 algorithm (Hus and Lord in "J Autism Dev Disord" 44(8):1996-2012, 2014) in 93 Dutch males with Autism Spectrum Disorder (ASD), schizophrenia, psychopathy or controls. Discriminative ability of the revised algorithm ASD cut-off…

  5. Modular synthesis of glycopolymers with well-defined sugar units in the side chain via Ugi reaction and click chemistry : hetero vs. homo

    NARCIS (Netherlands)

    Xue, Lulu; Xiong, Xinhong; Chen, Kui; Luan, Yafei; Chen, Gaojian; Chen, Hong

    2016-01-01

    For synthetic glycopolymers, multivalent carbohydrate-protein interactions have been mostly studied in homoglycopolymers so far. However, natural oligosaccharides tend to consist of various sugars and this kind of heterogeneity is used to tune affinity and selectivity towards a specific receptor.

  6. Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN3-Pincer Ligand

    KAUST Repository

    Pan, Yupeng

    2016-04-22

    An unsymmetrically protonated PN3-pincer complex in which ruthenium is coordinated by one nitrogen and two phosphorus atoms was employed for the selective generation of hydrogen from formic acid. Mechanistic studies suggest that the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved. Grabbing hold: A PN3-pincer complex was employed for the selective hydrogen generation from formic acid. Mechanistic studies suggest the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. DFT study of IR and Raman spectra of phosphotrihydrazone dendrimer with terminal phenolic groups

    Science.gov (United States)

    Furer, V. L.; Vandyukov, A. E.; Majoral, J. P.; Caminade, A. M.; Kovalenko, V. I.

    2017-09-01

    FT Raman and infrared spectra of phosphotrihydrazone (S)P[N(CH3)Ndbnd CHsbnd C6H4sbnd OH]3 (G0) were recorded. This compound is a zero generation phosphorus dendrimer with terminal phenolic groups. Optimal geometry and vibrational frequencies were calculated for G0 using the density functional theory (DFT). The molecule studied has C3 symmetry. In the molecule G0, each sbnd C6H4sbnd CHdbnd Nsbnd N(CH3)sbnd P arm is flat. Optimized geometric parameters correspond to experimental data. The core of the dendrimer manifests itself as a band at 647 cm-1 in the Raman spectrum of G0 related to Pdbnd S stretching. Phenolic end functions exhibit a well-defined band at 3374 cm-1 in the experimental IR spectrum of G0. The observed frequency of the OH stretching vibrations of the phenolic groups is lower than the theoretical value due to the intermolecular Osbnd H⋯O hydrogen bond. This hydrogen bond is also responsible for the higher intensity of this band in the experimental IR spectrum compared with the theoretical value. DFT calculations suggest full assignment of normal modes. Global and local descriptors characterize the reactivity of the core and end groups.

  8. Consistent Prebiotic Effect on Gut Microbiota With Altered FODMAP Intake in Patients with Crohn's Disease: A Randomised, Controlled Cross-Over Trial of Well-Defined Diets

    OpenAIRE

    Halmos, Emma P; Christophersen, Claus T.; Bird, Anthony R.; Shepherd, Susan J; Muir, Jane G.; Gibson, Peter R

    2016-01-01

    Objectives: Altering FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) intake has substantial effects on gut microbiota. This study aimed to investigate effects of altering FODMAP intake on markers of colonic health in patients with Crohn's disease. Methods: After evaluation of their habitual diet, 9 patients with clinically quiescent Crohn's disease were randomised to 21 days of provided low or typical (“Australian”) FODMAP diets with ≥21-day washout in betwee...

  9. Establishment and characterization of a highly tumourigenic and cancer stem cell enriched pancreatic cancer cell line as a well defined model system.

    Directory of Open Access Journals (Sweden)

    Johannes Fredebohm

    Full Text Available Standard cancer cell lines do not model the intratumoural heterogeneity situation sufficiently. Clonal selection leads to a homogeneous population of cells by genetic drift. Heterogeneity of tumour cells, however, is particularly critical for therapeutically relevant studies, since it is a prerequisite for acquiring drug resistance and reoccurrence of tumours. Here, we report the isolation of a highly tumourigenic primary pancreatic cancer cell line, called JoPaca-1 and its detailed characterization at multiple levels. Implantation of as few as 100 JoPaca-1 cells into immunodeficient mice gave rise to tumours that were histologically very similar to the primary tumour. The high heterogeneity of JoPaca-1 was reflected by diverse cell morphology and a substantial number of chromosomal aberrations. Comparative whole-genome sequencing of JoPaca-1 and BxPC-3 revealed mutations in genes frequently altered in pancreatic cancer. Exceptionally high expression of cancer stem cell markers and a high clonogenic potential in vitro and in vivo was observed. All of these attributes make this cell line an extremely valuable model to study the biology of and pharmaceutical effects on pancreatic cancer.

  10. New data on morphometrics, distribution and ecology of Mioscirtus wagneri (Kittary, 1849 (Orthoptera, Acrididae in Spain: is maghrebi a well defined subespecies?

    Directory of Open Access Journals (Sweden)

    Aparicio, J. M.

    2007-06-01

    Full Text Available We studied different populations of Mioscirtus wagneri (Kittary, 1859 in Spain assigned to subspecies maghrebi by Fernandes (1968 and obtained some new records for the species. To see if maghrebi is a consistent taxon for the Iberian populations, we performed a morphometric analysis involving 53 individuals from different origins considering body size (front of the head to tip of the abdomen; the shape of pronotum and presence of a second anterior notch or sulcus; length of the antennae and epiphallum, according to the characters used to define subspecies maghrebi. If maghrebi is consistent, we would expect intermediate sizes between wagneri and rogenhoferi, the other two well separated subspecies considered for M.w. However, in our measurements we obtained that body size is not intermediate between M. w. wagneri and M. w. rogenhoferi contrary to expectations if assuming the existence of maghrebi. Body size is similar to wagneri and further, we recorded some of the smallest individuals described so far. Also, the pronotum varied widely across and within populations showing different phenotypes that formerly were used to separate maghrebi and wagneri. Taking into account body size, pronotum, length of antenna and epiphallum, we think that differences between the studied Spanish populations and wagneri form are not enough to assign the studied populations to maghrebi. In the studied area, M.w. shows a narrow ecological niche inhabiting shores or proximities of hipersaline lagoons wherever Suaeda vera (Forsskål 1791, Chenopodiacea is present, M.w. uses this plant as refuge and food. The species also inhabits bare saline low grounds with scattered S vera. It presents a markedly discontinuous and patchy distribution in Spain, showing up punctually, where the microhabitat is appropriate. We obtained a morphometric variability with a significant association between body size and locality, and between body size and the colour of posterior wings in

  11. Preparation of well-defined dendrimer encapsulated ruthenium nanoparticles and their evaluation in the reduction of 4-nitrophenol according to the Langmuir-Hinshelwood approach.

    Science.gov (United States)

    Antonels, Nathan Charles; Meijboom, Reinout

    2013-11-05

    This study discusses the preparation of various sized dendrimer encapsulated ruthenium nanoparticles (RuDEN) with the use of the generation 4 (G4), generation 5 (G5), and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents. The size of the nanoparticles ranges from 1.1 to 2.2 nm. These catalysts were fully characterized using UV/vis spectrophotometry, infrared (IR) spectroscopy, and transmission electron microscopy (TEM). The RuDEN catalysts were evaluated in the reduction of 4-nitrophenol (4NP) in the presence of sodium borohydride (BH4(-)) for various concentrations of either. The kinetic data obtained were modeled to the Langmuir-Hinshelwood equation. The model allows the relation of the apparent rate constant to the total surface area S of the nanoparticle, the kinetic constant k which is related to the rate-determining step, and the adsorption constants K(4NP) and K(BH4) for 4NP and borohydride, respectively. These parameters were calculated for each of the RuDENs, proving the Langmuir-Hinshelwood model to be suitable for the kinetic evaluation of RuDENs in the catalytic reduction of 4NP.

  12. The EULAR Study Group for Registers and Observational Drug Studies

    DEFF Research Database (Denmark)

    Kearsley-Fleet, Lianne; Závada, Jakub; Hetland, Merete Lund

    2015-01-01

    OBJECTIVE: Under the auspices of the European League Against Rheumatism (EULAR), a study group of investigators representing European biologic DMARD (bDMARD) registers was convened. The purpose of this initial assessment was to collect and compare a cross section of patient characteristics...

  13. Synthesis of Well-Defined Copper "N"-Heterocyclic Carbene Complexes and Their Use as Catalysts for a "Click Reaction": A Multistep Experiment that Emphasizes the Role of Catalysis in Green Chemistry

    Science.gov (United States)

    Ison, Elon A.; Ison, Ana

    2012-01-01

    A multistep experiment for an advanced synthesis lab course that incorporates topics in organic-inorganic synthesis and catalysis and highlights green chemistry principles was developed. Students synthesized two "N"-heterocyclic carbene ligands, used them to prepare two well-defined copper(I) complexes and subsequently utilized the complexes as…

  14. Development of the first well-defined tungsten oxo alkyl derivatives supported on silica by SOMC: towards a model of WO3/SiO2 olefin metathesis catalyst

    KAUST Repository

    Mazoyer, Etienne

    2010-01-01

    A well-defined, silica-supported tungsten oxo alkyl species prepared by the surface organometallic chemistry approach displays high and sustained activity in propene metathesis. Remarkably, its catalytic performances outpace those of the parent imido derivative, underlining the importance of the oxo ligand in the design of robust catalysts. © 2010 The Royal Society of Chemistry.

  15. Synthesis of Well-Defined Copper "N"-Heterocyclic Carbene Complexes and Their Use as Catalysts for a "Click Reaction": A Multistep Experiment that Emphasizes the Role of Catalysis in Green Chemistry

    Science.gov (United States)

    Ison, Elon A.; Ison, Ana

    2012-01-01

    A multistep experiment for an advanced synthesis lab course that incorporates topics in organic-inorganic synthesis and catalysis and highlights green chemistry principles was developed. Students synthesized two "N"-heterocyclic carbene ligands, used them to prepare two well-defined copper(I) complexes and subsequently utilized the complexes as…

  16. Synthesis of novel well-defined poly(vinyl acetate)-b-poly(acrylonitrile) and derivatized water-soluble poly(vinyl alcohol)-b-poly(acrylic acid) block copolymers by cobalt-mediated radical polymerization

    NARCIS (Netherlands)

    Debuigne, A.; Warnant, J.; Jerome, R.; Voets, I.K.; Keizer, de A.; Cohen Stuart, M.A.; Detrembleur, C.

    2008-01-01

    Poly(vinyl acetate)¿Co(acac)2 macroinitiators, prepared by cobalt-mediated radical polymerization of vinyl acetate (VAc), were used to synthesize well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) block copolymers. Different solvents and temperatures were tested for the polymerizati

  17. Group-as-a-whole as a context for studying individual behaviour: A group diagnostic intervention

    OpenAIRE

    Dirk J. Geldenhuys

    2012-01-01

    Orientation: Traditionalists view group interventions from three perspectives: singletons, dyads and whole groups. The focus of this research was on interventions from the third perspective, that of the whole group, using a systems psychodynamic stance. Research purpose: The purpose of the research was to use group-as-a-whole to study individual behaviour in organisations.Motivation for the study: Team research and practice is not on a par with the complexities that teams actually experience....

  18. The Women in the Army Study Group

    Science.gov (United States)

    1976-12-01

    Research Institute for the Behavioral and Social Sciences has been tasked to validate maximum female content levels recommended by Training and...an overview, several conclusions can be made. First, a considerable void remains with regard to establishing a sound data base to support the decision...This point is supported throughout the study. It is clear that the original intent of Congress and, by extension, the intent of the American people

  19. Dialogical Approach Applied in Group Counselling: Case Study

    Science.gov (United States)

    Koivuluhta, Merja; Puhakka, Helena

    2013-01-01

    This study utilizes structured group counselling and a dialogical approach to develop a group counselling intervention for students beginning a computer science education. The study assesses the outcomes of group counselling from the standpoint of the development of the students' self-observation. The research indicates that group counselling…

  20. [(≢SiO)TaVCl2Me2]: A well-defined silica-supported tantalum(V) surface complex as catalyst precursor for the selective cocatalyst-free trimerization of ethylene

    KAUST Repository

    Chen, Yin

    2012-10-22

    On the surface of it: In the absence of co-catalyst, a well-defined silica-supported surface organometallic complex [(≢SiO)Ta VCl2Me2] selectively catalyzes the oligomerization of ethylene. The use of surface organometallic species allows three different pathways to be determined for the reduction of TaV to TaIII species under pressure of ethylene. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Striking difference between alkane and olefin metathesis using the well-defined precursor [≡Si-O-WMe5]: Indirect evidence in favour of a bifunctional catalyst W alkylidene-hydride

    KAUST Repository

    Riache, Nassima

    2015-01-01

    Metathesis of linear alkanes catalyzed by the well-defined precursor (≡Si-O-WMe5) affords a wide distribution of linear alkanes from methane up to triacontane. Olefin metathesis using the same catalyst and under the same reaction conditions gives a very striking different distribution of linear α-olefins and internal olefins. This shows that olefin and alkane metathesis processes occur via very different pathways.

  2. Group-analytic training groups for psychology students: A qualitative study

    DEFF Research Database (Denmark)

    Nathan, Vibeke Torpe; Poulsen, Stig

    2004-01-01

    This article presents results from an interview study of psychology students' experiences from group-analytic groups conducted at the University of Copenhagen. The primary foci are the significance of differences in themotivation participants'  personal aims of individual participantsfor...... participation in the group, the impact of the composition of participants on the group process, and the professional learning through the group experience. In general the interviews show a marked satisfaction with the group participation. In particular, learning about the importance of group boundaries...... and about being in the dual position of both helper and client is seen as important. However the fact that all group members are fellow students is challenging to the participants....

  3. GroupFinder: A Hyper-Local Group Study Coordination System

    Directory of Open Access Journals (Sweden)

    Joe Ryan

    2011-04-01

    Full Text Available GroupFinder is a system designed to help users working in groups let each other know where they are, what they are working on, and when they started. Students can use the GroupFinder system to arrange meetings within the library. GroupFinder also works with the phpScheduleIt room reservation system used to reserve group study rooms at the D.H. Hill Library at NCSU. Information from GroupFinder is presented on the GroupFinder web site, the mobile web site and on electronic bulletin boards within the library. How GroupFinder was developed from the initial concept through the implementation is covered in the article.

  4. Incorporating group correlations in genome-wide association studies using smoothed group Lasso.

    Science.gov (United States)

    Liu, Jin; Huang, Jian; Ma, Shuangge; Wang, Kai

    2013-04-01

    In genome-wide association studies, penalization is an important approach for identifying genetic markers associated with disease. Motivated by the fact that there exists natural grouping structure in single nucleotide polymorphisms and, more importantly, such groups are correlated, we propose a new penalization method for group variable selection which can properly accommodate the correlation between adjacent groups. This method is based on a combination of the group Lasso penalty and a quadratic penalty on the difference of regression coefficients of adjacent groups. The new method is referred to as smoothed group Lasso (SGL). It encourages group sparsity and smoothes regression coefficients for adjacent groups. Canonical correlations are applied to the weights between groups in the quadratic difference penalty. We first derive a GCD algorithm for computing the solution path with linear regression model. The SGL method is further extended to logistic regression for binary response. With the assistance of the majorize-minimization algorithm, the SGL penalized logistic regression turns out to be an iteratively penalized least-square problem. We also suggest conducting principal component analysis to reduce the dimensionality within groups. Simulation studies are used to evaluate the finite sample performance. Comparison with group Lasso shows that SGL is more effective in selecting true positives. Two datasets are analyzed using the SGL method.

  5. Ethnic helping and group identity : A study among majority group children

    NARCIS (Netherlands)

    Sierksma, Jellie; Thijs, Jochem; Verkuijten, Maykel

    2014-01-01

    Two vignette studies were conducted on children's evaluations of ethnic helping. In the first study, 272 native Dutch children (mean age = 10.7) evaluated a child who refused to help in an intra-group context (Dutch-Dutch or Turkish-Turkish) or inter-group context (Dutch-Turkish or Turkish-Dutch). C

  6. Ethnic Helping and Group Identity: A Study among Majority Group Children

    NARCIS (Netherlands)

    Sierksma, J.; Thijs, J.T.; Verkuyten, M.J.A.M.

    2014-01-01

    Two vignette studies were conducted on children's evaluations of ethnic helping. In the first study, 272 native Dutch children (mean age = 10.7) evaluated a child who refused to help in an intra-group context (Dutch-Dutch or Turkish-Turkish) or inter-group context (Dutch-Turkish or Turkish-Dutch). C

  7. Ethnic Helping and Group Identity: A Study among Majority Group Children

    NARCIS (Netherlands)

    Sierksma, J.; Thijs, J.T.; Verkuyten, M.J.A.M.

    2014-01-01

    Two vignette studies were conducted on children's evaluations of ethnic helping. In the first study, 272 native Dutch children (mean age = 10.7) evaluated a child who refused to help in an intra-group context (Dutch-Dutch or Turkish-Turkish) or inter-group context (Dutch-Turkish or Turkish-Dutch). C

  8. The Experiences of Expert Group Work Supervisors: An Exploratory Study

    Science.gov (United States)

    Atieno Okech, Jane E.; Rubel, Deborah

    2009-01-01

    Evaluation of group work supervision literature suggests that description of expert group work supervisors' experiences could be useful for expanding existing group work supervision practices and models. This study provided a systematic exploration of the experiences of expert group work supervisors during the supervision process. Results indicate…

  9. Group-as-a-whole as a context for studying individual behaviour: A group diagnostic intervention

    Directory of Open Access Journals (Sweden)

    Dirk J. Geldenhuys

    2012-01-01

    Full Text Available Orientation: Traditionalists view group interventions from three perspectives: singletons, dyads and whole groups. The focus of this research was on interventions from the third perspective, that of the whole group, using a systems psychodynamic stance. Research purpose: The purpose of the research was to use group-as-a-whole to study individual behaviour in organisations.Motivation for the study: Team research and practice is not on a par with the complexities that teams actually experience. Traditional group interventions use humanistic and functionalistic paradigms that do not consider the unconscious functioning of groups. Interventions that use the system psychodynamic paradigm could address these dynamics because they study behaviour of individual group members in the context of the group-as-a-whole. Research design, approach and method: The researcher conducted action research in a publishing company. He used purposive sampling and analysed the data using qualitative content analysis.Main findings: The researcher found that the group-as-a-whole partly explains the behaviour of team members and that intervening from this perspective could improve negative relationships.Practical/managerial implications: Managers can use interventions that use the groupas- a-whole concept as a diagnostic intervention to study and possibly change the complex behavioural issues that team members experience.Contribution/value-add: The findings give one an understanding of the behaviour of individual group members when one views it from a systems psychodynamic stance. Furthermore, the researcher proposes a group diagnostic intervention that will allow some of the root causes of poor interpersonal behaviour to surface and group members to diagnose and take ownership of their own behaviour.

  10. Study Abroad: The Reality of Building Dynamic Group Learning.

    Science.gov (United States)

    Ransbury, Molly K.; Harris, Sandra A.

    1994-01-01

    The collaborative effort of a professor of human development with expertise in group process and a general education professor with expertise in Greek mythology and culture uses a case study format to apply theoretical models of group dynamics to the travel and learning experience of study abroad. Implications for course design and group process…

  11. Professional Development within Collaborative Teacher Study Groups: Pitfalls and Promises

    Science.gov (United States)

    Stanley, Ann Marie

    2011-01-01

    Teacher study groups are often thought to be effective professional development structures. Such teacher communities may foster teacher learning through a collaborative culture and the codification of group members' collective knowledge. However, not all study groups are effective professional development. This article is a discussion of factors…

  12. Piezoelectricity in quasicrystals: A group-theoretical study

    Indian Academy of Sciences (India)

    K Rama Rao; P Hemagiri Rao; B S K Chaitanya

    2007-03-01

    Group-theoretical methods have been accepted as exact and reliable tools in studying the physical properties of crystals and quasicrystalline materials. By group representation theory, the maximum number of non-vanishing and independent second- order piezoelectric coefficients required by the seven pentagonal and two icosahedral point groups - that describe the quasicrystal symmetry groups in two and three dimensions - is determined. The schemes of non-vanishing and independent second-order piezoelectric tensor components needed by the nine point groups with five-fold rotations are identified and tabulated employing a compact notation. The results of this group-theoretical study are briefly discussed.

  13. WMe6 tamed by silica: Si-O-WMe5 as an efficient, well-defined species for alkane metathesis, leading to the observation of a supported W-methyl/methylidyne species

    KAUST Repository

    Samantaray, Manoja

    2014-01-22

    The synthesis and full characterization of a well-defined silica-supported ≡Si-O-W(Me)5 species is reported. Under an inert atmosphere, it is a stable material at moderate temperature, whereas the homoleptic parent complex decomposes above -20 °C, demonstrating the stabilizing effect of immobilization of the molecular complex. Above 70 °C the grafted complex converts into the two methylidyne surface complexes [(≡SiO-)W(≡CH) Me2] and [(≡SiO-)2W(≡CH)Me]. All of these silica-supported complexes are active precursors for propane metathesis reactions. © 2013 American Chemical Society.

  14. Improving Group Processes in Transdisciplinary Case Studies for Sustainability Learning

    Science.gov (United States)

    Hansmann, Ralf; Crott, Helmut W.; Mieg, Harald A.; Scholz, Roland W.

    2009-01-01

    Purpose: Deficient group processes such as conformity pressure can lead to inadequate group decisions with negative social, economic, or environmental consequences. The study aims to investigate how a group technique (called INFO) improves students' handling of conformity pressure and their collective judgments in the context of a…

  15. Cognitive Behavioral Principles within Group Mentoring: A Randomized Pilot Study

    Science.gov (United States)

    Jent, Jason F.; Niec, Larissa N.

    2009-01-01

    This study evaluated the effectiveness of a group mentoring program that included components of empirically supported mentoring and cognitive behavioral techniques for children served at a community mental health center. Eighty-six 8- to 12-year-old children were randomly assigned to either group mentoring or a wait-list control group. Group…

  16. Academic and Personal Development through Group Work: An Exploratory Study

    Science.gov (United States)

    Steen, Sam

    2011-01-01

    This exploratory study linked academic and personal development within a group counseling intervention. A pre-test post-test research design compared social skills, learning behaviors, and achievement with a convenience sample and control group of students from three elementary schools. For the treatment group, grade point average in Language Arts…

  17. Speaking up in groups: a cross-level study of group voice climate and voice.

    Science.gov (United States)

    Morrison, Elizabeth Wolfe; Wheeler-Smith, Sara L; Kamdar, Dishan

    2011-01-01

    Despite a growing body of research on employee voice—defined as the discretionary communication of ideas, suggestions, or opinions intended to improve organizational or unit functioning—the effects of shared or collective-level cognitions have received scant attention. There has also been relatively little research on voice within work groups. Our goal in this study was to address these important gaps by focusing on the effects of group-level beliefs about voice (i.e., group voice climate) on individual voice behavior within work groups. We conducted a cross-level investigation of voice behavior within 42 groups of engineers from a large chemical company. Consistent with our hypotheses, group voice climate was highly predictive of voice and explained variance beyond the effects of individual-level identification and satisfaction, and procedural justice climate. Also consistent with predictions, the effect of identification on voice was stronger in groups with favorable voice climates. These findings provide evidence that voice is shaped not just by individual attitudes and perceptions of the work context, as past research has shown, but also by group-level beliefs. The results also highlight the importance of broadening our conceptual models of voice to include shared cognitions and of conducting additional cross-level research on voice.

  18. Follow Up Study of Group Counseling with Underachieving College Freshmen.

    Science.gov (United States)

    Valine, Warren J.

    The purpose of this study was to report long-range effects of group counseling and the college growth experience of students who were identified as underachievers and were enrolled as freshmen during the fall of 1969. Five variables were selected for this study as having possible influence on self-concept: (1) group, (2) education, (3) status, (4)…

  19. Cooperative Study Groups: Give Your Students the Home Team Advantage

    Science.gov (United States)

    Lerma, Tony

    2007-01-01

    In this article I discuss the factors that led me to implement study groups in the teaching of mathematics. An important influence in this decision began with an experimental study conducted with two College Algebra classes in which students were randomly assigned to treatment groups. While there was no statistical difference between the study…

  20. 32nd European Study Group with Industry, Final Report

    DEFF Research Database (Denmark)

    ESGI (European Study Group with Industry) is Europe's leading workshop for interaction between mathematicians and industry. These workshops have taken place in Great Britain for a number of years, going back to 1968 when Prof. Alan Tayler initiated the so-called Oxford Study Group with Industry....... The coordiantion of the study groups is now done by the European Consortium for Mathematics in Industry (ECMI).This is the final report for the first study group in Denmark, (and the first ESGI outside Great Britain). Six Danish companies brought problems to the Study Group, requiring a wide range of mathematical...... a model describing the chlorination of swimming pools.LEGO wanted an algorithm for building an arbitrary model with LEGO bricks in stable manner.SCANtechnology wanted an algorithm to identify features in an image from a 3D laser scanning....

  1. Religious and national group identification in adolescence: a study among three religious groups in Mauritius.

    Science.gov (United States)

    Ng Tseung-Wong, Caroline; Verkuyten, Maykel

    2013-01-01

    Religious group identification is an important but understudied social identity. The present study investigates religious group identification among adolescents of different faiths (Hindu, Muslim, Christian) living in multicultural Mauritius. It further explores how religious and national group identities come together among religious majority and minority adolescents. For three age groups (11 to 19 years, N = 2152) we examined the strength of adolescents' religious and national group identification, the associations between these two identities, and the relationships to global self-esteem. Across age and religious group, participants reported stronger identification with their religious group than with the nation. Identification with both categories declined with age, with the exception of Muslims, whose strong religious identification was found across adolescence. The association between religious and national identification was positive, albeit stronger for the majority group of Hindus and for early adolescents. We examined the manner in which religious and national identities come together using a direct self-identification measure and by combining the separate continuous measures of identification. Four distinct clusters of identification (predominant religious identifiers, dual identifiers, neutrals, and separate individuals) that were differently associated with global self-esteem were found. Dual identifiers reported the highest level of global self-esteem. The clusters of identification did not fully correspond to the findings for the direct self-identification measure. The results are discussed in terms of the meaning of dual identity and the positive manner in which adolescents can manage their multiple identities while taking into account the ideological framework in which those identities are played out.

  2. STUDIES ON HUMAN FALLOPIAN TUBAL EPITHELIUM IN DIFFERENT AGE GROUPS

    Directory of Open Access Journals (Sweden)

    Jayasri

    2016-02-01

    Full Text Available BACKGROUND AND AIMS The “fallopian tubes” (oviducts or uterine tubes are long paired flexuous reproductive organ which transports ova, spermatozoa, zygotes, the pre-implantation morulae and blastocyst. It has major role during reproductive period, but it remains as if vestigial organ before puberty and after menopause. Due to increasing rate of tubal block and infertility, oviducts and their structures gaining importance and have become a subject of research in present days particularly epithelium. The aim of the study is to ascertain any histological difference of tubal epithelium in different age groups and the research work could be utilized for investigation and management of infertility. MATERIALS AND METHODS Seven samples of each group i.e., prereproductive, reproductive & postmenopausal were collected from fresh unembalmed human cadavers received in the department of Anatomy, FAA Medical College, Barpeta, Assam. The slides were prepared using the standard laboratory procedure. Under low and high power objectives the type of cells were observed and epithelial height was measured in the different segments. Stress was given for any significant difference of epithelial height between the different age groups. RESULTS Study revealed that among the groups within the same segment, epithelial height was recorded highest (33.57µm in reproductive group as against the lowest (22.91µm in post-menopausal group. Epithelial structures of the prereproductive and reproductive groups were significantly differed (p<0.01 from the postmenopausal group. CONCLUSIONS From the findings of the present study it can be concluded that: 1. In all the groups fallopian tubal epithelium is of simple columnar type and contains three types of cells. Cells are ciliated, secretory & peg (intercalary cells. 2. In all the groups same type of increasing trend of epithelial height from intramural segment to ampullary segment was recorded. 3. In intergroup comparison of

  3. 结构明确的可降解醛基功能化含糖纳米微球的制备%PREPARATION OF WELL-DEFINED AND DEGRADABLE ALDEHYDE-FUNCTIONALIZED GLYCOPOLYMERIC NANOSPHERES

    Institute of Scientific and Technical Information of China (English)

    肖乃玉; 钟乐; 翟万京; 白卫东

    2012-01-01

    composition was determined by taking the ratio of peak areas of aldehyde protons of IVDG to that of of BMDO. It is observed that the mole fraction of BMDO was less in copolymers as compared to that in the initial feed. The result was mostly because the BMDO radical is neighbor to two electron-rich oxygen atoms so as to have lower reactivity as compared to IVDG radical. The copolymer compositions and structural characterization were obtained from 'H-NMR spectroscopy. Degradation behavior of these copolymers was also investigated. Removal of protective isopropylidene groups from the sugar residue in poly( BMDO-co-IVDG) was carried out quantitatively using 88% formic acid at room temperature, yielding a novel amphiphilic copolymer containing both galactopyranose and aldehyde functionalities. These amphiphilic glycopolymers self-assembled into well-defined degradable and biocompatible aldehyde-functionalized polymeric nanospheres in aqueous solutions without recourse to any surfactant. The nanospheres obtained from the resultant glycopolymer are possible to be used as nanoparticle targeted drug-delivery system.

  4. Grassroots Growth: The Evolution of a Teacher Study Group

    Science.gov (United States)

    Maloney, Dana; Moore, Terry; Taylor, Monica

    2011-01-01

    Four years ago, a group of teachers lingered after a district meeting, sharing a conversation about encouraging social responsibility in the school district of Tenafly, New Jersey. That conversation led to the eventual formation of a teacher study group, a grassroots professional learning community that has impacted its members and the school…

  5. Study on Concept of Centralization and Decentralization Group Decision Making

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qin-sheng; XI You-min; WANG Ying-luo

    2002-01-01

    The paper extracts the concept of Centralization Group Decision Making (CGDM) and Decentralization Group Decision Making (DGDM) from management systems on bases of studies on Informational Centralization Process (ICP) and Informational Decentralization Process (IDP), then the similarities and differences between CGDM and DGDM are presented. Further, the taxonomy of CGDM and DGDM is researched.

  6. Learning How to Improve Vocabulary Instruction through Teacher Study Groups

    Science.gov (United States)

    Dimino, Joseph; Taylor, Mary Jo

    2009-01-01

    Professional development with proven positive effects on vocabulary instruction and student achievement: that's what reading teachers are looking for, and that's what the Teacher Study Group (TSG) model delivers. With the nine complete TSG sessions in this book, K-8 teachers will form dynamic in-school learning groups with their fellow educators…

  7. Educator Study Groups: A Professional Development Tool to Enhance Inclusion

    Science.gov (United States)

    Herner-Patnode, Leah

    2009-01-01

    Professional development can take many forms. The most effective development includes individual educators in the formation and planning process. Educator study groups are one form of professional development that allows major stakeholders in the education process the autonomy to develop individual and group goals. This often translates into an…

  8. Bion's thinking about groups: a study of influence and originality.

    Science.gov (United States)

    Schneider, John A

    2015-04-01

    One of Bion's least-acknowledged contributions to psychoanalytic theory is his study of the relationship between the mind of the individual (the ability to think), the mentalities of groups of which the individual is a member, and the individual's bodily states. Bion's early work on group therapy evolved into a study of the interplay between mind and bodily instincts associated with being a member of a group, and became the impetus for his theory of thinking. On the foundation of Bion's ideas concerning this interaction among the thinking of the individual, group mentality, and the psyche-soma, the author presents his thoughts on the ways in which group mentality is recognizable in the analysis of individuals.

  9. Mapping Future Education and Training: Group Concept Mapping Study

    NARCIS (Netherlands)

    Stoyanov, Slavi; Hoogveld, Bert; Kirschner, Paul A.

    2010-01-01

    Stoyanov, S., Hoogveld, A. W. M., & Kirschner, P. A. (2010). Mapping Future Education and Training: Group Concept Mapping Study. Heerlen, The Netherlands: Open University of the Netherlands; EU Forlic project.

  10. Open mic: Introduction to the CERN Study Group

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Mozilla Study Groups are knowledge- and skill-sharing meet-ups for people to get help with their research or work on open-science projects. A CERN chapter was launched recently and you are invited to participate!

  11. Mapping Future Education and Training: Group Concept Mapping Study

    NARCIS (Netherlands)

    Stoyanov, Slavi; Hoogveld, Bert; Kirschner, Paul A.

    2010-01-01

    Stoyanov, S., Hoogveld, A. W. M., & Kirschner, P. A. (2010). Mapping Future Education and Training: Group Concept Mapping Study. Heerlen, The Netherlands: Open University of the Netherlands; EU Forlic project.

  12. Novice Teachers Learning through Participation in a Teacher Study Group

    Science.gov (United States)

    Lambson, Dawn

    2010-01-01

    Using Lave and Wenger's framework of legitimate peripheral participation in communities of practice, this case study explores the experiences of three novice teachers engaged with more experienced teachers in a teacher study group during their first year of teaching. The study illustrates how, over time, the novices moved from more peripheral to…

  13. A mentored cooperative group pilot study: atrophic vaginitis.

    Science.gov (United States)

    Lester, Joanne L; Jarvis, Chandler; Bartholomew, Deborah; Yee, Lisa

    2014-02-01

    To review nursing research initiatives from two cooperative groups and outline a pilot study performed by a junior nurse researcher mentored by cooperative group nurse researchers and institutional physicians. PubMed, Cochrane Library, Scopus, World Wide Web. Nursing research can be initiated and led by nurses in the cooperative group setting. The team approach model of research includes several disciplines to examine multiple facets of the same problem, or of multiple problems that a cancer patient may face. This new model will enable a greater number of nurse researchers to investigate symptom management, survivorship, and quality-of-life issues. Nurse researchers should be included in every cooperative group study to investigate nurse-sensitive outcomes and issues related to symptom management, survivorship, and quality of life. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. IRT studies of many groups: The alignment method

    Directory of Open Access Journals (Sweden)

    Bengt eMuthen

    2014-09-01

    Full Text Available Asparouhov and Muthen (forthcoming presented a new method for multiple-group confirmatory factor analysis (CFA, referred to as the alignment method. The alignment method can be used to estimate group-specific factor means and variances without requiring exact measurement invariance. A strength of the method is the ability to conveniently estimate models for many groups, such as with comparisons of countries. This paper focuses on IRT applications of the alignment method. An empirical investigation is made of binary knowledge items administered in two separate surveys of a set of countries. A Monte Carlo study is presented that shows how the quality of the alignment can be assessed.

  15. An infertile case of 47,XYY syndrome without autistic spectrum: Cost effective well-define of extra Y chromosome by GTG, C bandings, QF-PCR and FISH analyses

    Directory of Open Access Journals (Sweden)

    Özturk Özdemir

    2016-12-01

    Full Text Available The Autism Spectrum Disorders (ASD was frequently reported in autosomal and sex chromosome abnormalities and limited findings pointed out the Y chromosome. In the current case, it was aimed to identify the genetic cause for a man without autism profiles using combined cytogenetic and molecular genetic techniques. Automated karyotype analysis was made after combined methods with GTG, C bandings, QF-PCR and FISH techniquesfor the current case. Additional Y chromosome was identified after conventional GTG and C-banded karyotype analysis. The current case of 47,XYY syndrome was reported due to without autistic profiles such as language and social impairment. The proband’s karyotype was determined as 47,XYY. No other numerical and/or structural chromosomal abnormalities were detected in the karyotype analysis. Cytogenetic methods combined with cost-effective techniques such as C, GTG banding and FISH provide well-define of extra Y chromosome in the presented case of without autistic spectrum. Both Y chromosomes were in the same size and C-banded profiles in the current proband pointed out that both are originated from one chromosome by endoreduplication Y chromosome after zigot formation

  16. Well-Defined Surface Species [(≡Si - O -)W(=O)Me3] Prepared by Direct Methylation of [(≡Si - O -)W(=O)Cl3], a Catalyst for Cycloalkane Metathesis and Transformation of Ethylene to Propylene

    KAUST Repository

    Hamieh, Ali Imad Ali

    2015-04-03

    The silica-supported tungsten oxo-trimethyl complex [(≡Si - O -)W(=O)Me3] was synthesized using a novel SOMC synthetic approach. By grafting the inexpensive stable compound WOCl4 on the surface of silica, partially dehydroxylated at 700 °C (SiO2-700), a well-defined monopodal surface complex [(≡Si - O -)W(=O)Cl3] was produced. The supported complex directly methylated with ZnMe2 and transformed into [(≡Si - O -)W(=O)Me3], which we fully characterized by microanalysis, IR, mass balance and SS NMR (1H, 13C, 1H-13C HETCOR, 1H-1H DQ and TQ). [(≡Si - O)W(=O)Me3] has two conformational isomers on the surface at room temperature. The conversion of one to the other was observed at 318 K by variable-temperature 13C CP/MAS and 1H spin echo MAS solid-state NMR; this was also confirmed by NMR and DFT calculations. [(≡Si - O)W(=O)Me3] was found to be active in cyclooctane metathesis and to have a wide distribution range in ring-contracted and ring-expanded products. In addition, [(≡Si - O)W(=O)Me3] proved to be highly active for selective transformation of ethylene to propylene compared to other silica-supported organometallic complexes. (Chemical Equation Presented). © 2015 American Chemical Society.

  17. Motivating Study Groups across the Disciplines in Secondary Schools

    Science.gov (United States)

    Styslinger, Mary E.; Clary, Deidre M.; Oglan, Victoria A.

    2015-01-01

    This article introduces Project RAISSE: Reading Assistance Initiative for Secondary School Educators and shares the findings of a study into those factors found to motivate study group participants at two rural high schools in the southern USA. The research team collected qualitative data over a two-year period, including interviews, artifacts,…

  18. Study: California Ethnic Groups Seeing Increased Cancer Rates

    Science.gov (United States)

    Black Issues in Higher Education, 2005

    2005-01-01

    A statewide study on cancer and ethnicity hints that cancer rates among immigrant groups may be tied to their degree of assimilation into American culture. The study, released by the University of Southern California's Norris Comprehensive Cancer Center, marks the first statewide look at cancer rates among Vietnamese and South Asians and provides…

  19. Evaluation of support group interventions for children in troubled families: study protocol for a quasi-experimental control group study.

    Science.gov (United States)

    Skerfving, Annemi; Johansson, Fredrik; Elgán, Tobias H

    2014-01-24

    Support groups for children in troubled families are available in a majority of Swedish municipalities. They are used as a preventive effort for children in families with different parental problems such as addiction to alcohol/other drugs, mental illness, domestic violence, divorce situations, or even imprisonment. Children from families with these problems are a well-known at-risk group for various mental health and social problems. Support groups aim at strengthening children's coping behaviour, to improve their mental health and to prevent a negative psycho-social development. To date, evaluations using a control-group study design are scarce. The aim of the current study is to evaluate the effects of support groups. This paper describes the design of an effectiveness study, initially intended as a randomized controlled trial, but instead is pursued as a quasi-experimental study using a non-randomized control group. The aim is to include 116 children, aged 7-13 years and one parent/another closely related adult, in the study. Participants are recruited via existing support groups in the Stockholm county district and are allocated either into an intervention group or a waiting list control group, representing care as usual. The assessment consists of questionnaires that are to be filled in at baseline and at four months following the baseline. Additionally, the intervention group completes a 12-month follow-up. The outcomes include the Strength and Difficulties Questionnaire (SDQ S11-16), the Kids Coping Scale, the "Ladder of life" which measures overall life satisfaction, and "Jag tycker jag är" (I think I am) which measures self-perception and self-esteem. The parents complete the SDQ P4-16 (parent-report version) and the Swedish scale "Familjeklimat" (Family Climate), which measures the emotional climate in the family. There is a need for evaluating the effects of support groups targeted to children from troubled families. This quasi-experimental study

  20. A Case Study: Novel Group Interactions through Introductory Computational Physics

    CERN Document Server

    Obsniuk, Michael J; Caballero, Marcos D

    2015-01-01

    With the advent of high-level programming languages capable of quickly rendering three-dimensional simulations, the inclusion of computers as a learning tool in the classroom has become more prevalent. Although work has begun to study the patterns seen in implementing and assessing computation in introductory physics, more insight is needed to understand the observed effects of blending computation with physics in a group setting. In a newly adopted format of introductory calculus-based mechanics, called Projects and Practices in Physics, groups of students work on short modeling projects -- which make use of a novel inquiry-based approach -- to develop their understanding of both physics content and practice. Preliminary analyses of observational data of groups engaging with computation, coupled with synchronized computer screencast, has revealed a unique group interaction afforded by the practices specific to computational physics -- problem debugging.

  1. Hypovitaminosis D according to psychiatric diagnosis groups: A study with control group

    Directory of Open Access Journals (Sweden)

    Derya Güliz Mert

    2016-03-01

    Full Text Available Objective: One of the risk factor for different psychiatric disorders has been indicated as hypovit-aminosis D. The present study aimed to compare 25 (OH D level between 4 different types of psychiatric disorders (schizophrenia, bipolar disorder, depression and anxiety disorder and healthy controls, and to assess the risk factors of hypovitaminosis D in psychiatric inpatients. Method: This retrospective study included 974 individuals [depression (n=553, bipolar disorder (n=135, schizophrenia (n=186 and anxiety disorder (n=100] who received inpatient treatment in psychiatry clinic between 2012 and 2014, and 574 individuals in control group who were not diagnosed with a psychiatric condition. A 25 (OH D level less than 21 ng/mL was considered to indicate hypovitaminosis D. Results: 25 (OH D level average of the control group was found to be significantly higher than that of the four psychiatric diagnosis groups (p0.05. Lo-gistic regression analysis of the study parameters suggested that the female gender (odds ratio: 3.46; 95% confidence interval: 0.99-1.01, winter and spring seasons (odds ratio: 2.56; 95% con-fidence interval: 1.69-3.86 and odds ratio: 2.03; 95% confidence interval: 1.33-3.11, respectively were significant predictors in level of vitamin D in psychiatric inpatients. Conclusions: Hypovitaminosis D is a condition that frequently exists in inpatients in psychiatry clinic suffering from schizophrenia, bipolar disorder, anxiety disorder and depression. Being a female, winter and spring are the most remarkable risk factors in these patients.

  2. Revitalising PBL groups: evaluating PBL with study teams.

    Science.gov (United States)

    Moust, Jos; Roebertsen, Herma; Savelberg, Hans; De Rijk, Angelique

    2005-03-01

    In problem-based learning (PBL), students are actively engaged with psychological learning principles as activation of prior knowledge, elaboration and organization of knowledge. In their tutorial groups, however, students do not always apply these principles when working with a procedure like the "Seven-Jump" method. To stimulate students to use these principles more often, they were offered another format within a PBL context: PBL with study teams. During the period of self-study, students work on a regular basis in so-called study teams, small groups of 3-4 persons. In these groups they explain to each other their learning outcomes, clarify for each other their problems while studying texts and organize their knowledge to present this to the members of other study teams in their tutorial group. Previous research showed that students spent more time on self-study in a PBL with study team condition than in a traditional PBL context. In this study the achievement as well as appreciation of students participating in a PBL with study teams' environment, is compared with students working in a traditional PBL environment. To determine whether PBL with study teams differs from the traditional PBL environment in students' appreciation and study time. We conducted an experiment in two blocks over two years. Questionnaires were administered to collect data on appreciation and time for self-study. Students' appreciation of the two formats did not differ much. The large standard deviations indicate considerable differences in appreciation between individual students. Appreciation was slightly higher in the second experiment when instructions about how to collaborate were less strict. Students devoted twice as many hours studying in the study group format compared with the traditional PBL format. The students indicated that they enjoyed the format but that the increased workload disturbed their customary study rhythm. Assessment scores and tutors'impressions suggest that

  3. A Comparative Study of Group Key Management in MANET

    Directory of Open Access Journals (Sweden)

    M. El-Bashary,

    2015-08-01

    Full Text Available A Mobile Ad-Hoc Network (MANET is a self organized network, with no fixed infrastructure, limited resources and limited physical security. Security in such an environment is an essential requirement. Key management is a salient element in MANET security. It is responsible for key generation, storage, distribution, updating, revocation, deleting, and archiving. Key management protocols are classified into symmetric, asymmetric, group, and hybrid. Group key management is a point of interest for researchers with the growing usage of mobile devices and the rising of multicast communication. This paper surveys different approaches in group key management schemes. A comparative study is demonstrated in terms of reliability, computational complexity, storage cost, communication overheads, pre-requirements, security levels, robustness, vulnerabilities, scalability, energy and mobility. Finally, the study concludes the pros and cons of each protocol.

  4. Ethics reflection groups in community health services: an evaluation study.

    Science.gov (United States)

    Lillemoen, Lillian; Pedersen, Reidar

    2015-04-17

    Systematic ethics support in community health services in Norway is in the initial phase. There are few evaluation studies about the significance of ethics reflection on care. The aim of this study was to evaluate systematic ethics reflection in groups in community health (including nursing homes and residency), - from the perspectives of employees participating in the groups, the group facilitators and the service managers. The reflection groups were implemented as part of a research and development project. A mixed-methods design with qualitative focus group interviews, observations and written reports were used to evaluate. The study was conducted at two nursing homes, two home care districts and a residence for people with learning disabilities. Participants were employees, facilitators and service managers. The study was guided by ethical standard principles and was approved by the Norwegian Social Science Data Services. We found support for ethics reflection as a valuable measure to strengthen clinical practice. New and improved solutions, more cooperation between employees, and improved collaboration with patients and their families are some of the results. No negative experiences were found. Instead, the ethics reflection based on experiences and challenges in the workplace, was described as a win-win situation. The evaluation also revealed what is needed to succeed and useful tips for further development of ethics support in community health services. Ethics reflection groups focusing on ethical challenges from the participants' daily work were found to be significant for improved practice, collegial support and cooperation, personal and professional development among staff, facilitators and managers. Resources needed to succeed were managerial support, and anchoring ethics sessions in the routine of daily work.

  5. SU-E-J-115: Correlation of Displacement Vector Fields Calculated by Deformable Image Registration Algorithms with Motion Parameters of CT Images with Well-Defined Targets and Controlled-Motion

    Energy Technology Data Exchange (ETDEWEB)

    Jaskowiak, J; Ahmad, S; Ali, I [University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Alsbou, N [Ohio Northern University, Ada, OH (United States)

    2015-06-15

    Purpose: To investigate correlation of displacement vector fields (DVF) calculated by deformable image registration algorithms with motion parameters in helical axial and cone-beam CT images with motion artifacts. Methods: A mobile thorax phantom with well-known targets with different sizes that were made from water-equivalent material and inserted in foam to simulate lung lesions. The thorax phantom was imaged with helical, axial and cone-beam CT. The phantom was moved with a cyclic motion with different motion amplitudes and frequencies along the superior-inferior direction. Different deformable image registration algorithms including demons, fast demons, Horn-Shunck and iterative-optical-flow from the DIRART software were used to deform CT images for the phantom with different motion patterns. The CT images of the mobile phantom were deformed to CT images of the stationary phantom. Results: The values of displacement vectors calculated by deformable image registration algorithm correlated strongly with motion amplitude where large displacement vectors were calculated for CT images with large motion amplitudes. For example, the maximal displacement vectors were nearly equal to the motion amplitudes (5mm, 10mm or 20mm) at interfaces between the mobile targets lung tissue, while the minimal displacement vectors were nearly equal to negative the motion amplitudes. The maximal and minimal displacement vectors matched with edges of the blurred targets along the Z-axis (motion-direction), while DVF’s were small in the other directions. This indicates that the blurred edges by phantom motion were shifted largely to match with the actual target edge. These shifts were nearly equal to the motion amplitude. Conclusions: The DVF from deformable-image registration algorithms correlated well with motion amplitude of well-defined mobile targets. This can be used to extract motion parameters such as amplitude. However, as motion amplitudes increased, image artifacts increased

  6. Commonwealth Defence Science Organisation (CDSO Food Study Group (FSG

    Directory of Open Access Journals (Sweden)

    J. M. Watts

    1984-04-01

    Full Text Available The Food Study Group (FSG under Commonwealth Defence Science Organisation was established in 1962 to review major items of Defence research programmes and exchange scientific information in the commonwealth countries. This paper gives an insight into the set-up, terms of reference, membership and the way research programmes are conceived and dealt with.

  7. Effective Single-Parent Training Group Program: Three System Studies

    Science.gov (United States)

    Briggs, Harold E.; Miller, Keva M.; Orellana, E. Roberto; Briggs, Adam C.; Cox, Wendell H.

    2013-01-01

    Objective: This study highlights Dr. Elsie Pinkston and colleagues' research on the effectiveness of behavior parent training and examines the application of single-parent training group (SPG) programs to three parent-child dyads exposed to distressed family circumstances. Methods: Single-system evaluation designs were conducted with two…

  8. TRICARE Fourth Generation Study Group - Exploring the Way Forward

    Science.gov (United States)

    2011-01-26

    JAN 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE TRICARE Fourth Generation Study Group - Exploring the...1ncludes all AD, AOFMIGRIGRFM, and unclef 65 RETIRETFMIOTH, exclucbng 65+ Albers Equal Area Prqect10n, 2011 2011 MHS Conference Five Models  TRICARE

  9. A Joint GMRT/X-ray study of galaxy groups

    CERN Document Server

    O'Sullivan, E; Vrtilek, J M; Raychaudhuri, S; Athreya, R; Venturi, T; David, L P

    2009-01-01

    We present results from combined low-frequency radio and X-ray studies of nearby galaxy groups. We consider two main areas: firstly, the evolutionary process from spiral-dominated, HI-rich groups to elliptical-dominated systems with hot, X-ray emitting gas halos; secondly, the mechanism of AGN feedback which appears to balance radiative cooling of the hot halos of evolved groups. The combination of radio and X-ray observations provides a powerful tool for these studies, allowing examination of gas in both hot and cool phases, and of the effects of shock heating and AGN outbursts. Low-frequency radio data are effective in detecting older and less energetic electron populations and are therefore vital for the determination of the energetics and history of such events. We present results from our ongoing study of Stephan's Quintet, a spiral-rich group in which tidal interactions and shock heating appear to be transforming HI in the galaxies into a diffuse X-ray emitting halo, and show examples of AGN feedback fr...

  10. Unilateral neglect and perceptual parsing: a large-group study.

    Science.gov (United States)

    Neppi-Mòdona, Marco; Savazzi, Silvia; Ricci, Raffaella; Genero, Rosanna; Berruti, Giuseppina; Pepi, Riccardo

    2002-01-01

    Array-centred and subarray-centred neglect were disambiguated in a group of 116 patients with left neglect by means of a modified version of the Albert test in which the central column of segments was deleted so as to create two separate sets of targets grouped by proximity. The results indicated that neglect was more frequent in array- than subarray-centred coordinates and that, in a minority of cases, neglect co-occurred in both coordinate-systems. The two types of neglect were functionally but not anatomically dissociated. Presence of visual field defects was not prevalent in one type of neglect with respect to the other. These data contribute further evidence to previous single-case and small-group studies by showing that neglect can occur in single or multiple reference frames simultaneously, in agreement with current neuropsychological, neurophysiological and computational concepts of space representation.

  11. Renormalization group study of damping in nonequilibrium field theory

    CERN Document Server

    Zanella, J

    2006-01-01

    In this paper we shall study whether dissipation in a $\\lambda\\phi^{4}$ may be described, in the long wavelength, low frequency limit, with a simple Ohmic term $\\kappa\\dot{\\phi}$, as it is usually done, for example, in studies of defect formation in nonequilibrium phase transitions. We shall obtain an effective theory for the long wavelength modes through the coarse graining of shorter wavelengths. We shall implement this coarse graining by iterating a Wilsonian renormalization group transformation, where infinitesimal momentum shells are coarse-grained one at a time, on the influence action describing the dissipative dynamics of the long wavelength modes. To the best of our knowledge, this is the first application of the nonequilibrium renormalization group to the calculation of a damping coefficient in quantum field theory.

  12. Ab-Initio Study of the Group 2 Hydride Anions

    Science.gov (United States)

    Harris, Joe P.; Wright, Timothy G.; Manship, Daniel R.

    2013-06-01

    The beryllium hydride (BeH)- dimer has recently been shown to be surprisingly strongly bound, with an electronic structure which is highly dependent on internuclear separation. At the equilibrium distance, the negative charge is to be found on the beryllium atom, despite the higher electronegativity of the hydrogen. The current study expands this investigation to the other Group 2 hydrides, and attempts to explain these effects. M. Verdicchio, G. L. Bendazzoli, S. Evangelisti, T. Leininger J. Phys. Chem. A, 117, 192, (2013)

  13. Microscopic study of human spleen in different age groups

    Directory of Open Access Journals (Sweden)

    Lizamma Alex

    2015-07-01

    Full Text Available Background: The microscopic structure of spleen is variable depending on the developmental stage of the organ, and the age and immune status of the individual. The aim of the investigation was to study the microscopic structure of human spleen in different age groups, starting from a six month old foetus up to the eighth decade of life. Methods: Seventy formalin fixed human spleens obtained postmortem, were included in the study. They were classified into different age groups, in both sexes, for a detailed study of the microscopic details. Results: The white pulp of spleen showed peri-arteriolar lymphatic sheath (PALS and lymphatic follicles. The corona or mantle zone and the germinal centre were discernible in many of the Malpighian bodies. The marginal zone separating the red pulp from the white pulp also could be clearly demarcated. The marginal sinus and peri-follicular zone could be seen in some sections only. The capsule thickness, trabecular network, cellularity of white pulp and red pulp, the connective tissue framework seen in the red pulp etc., showed variations in the different age groups. Conclusion: The microscopic structure of spleen varies in different age groups, with the PALS and the white pulp showing scanty cellularity in the six month foetus, and almost uniform cellularity in all areas of spleen at full term. Thereafter the follicles showed increase in its cellularity up to the third decade, and then seemed becoming progressively atrophic. Further studies are required on age related changes in the cellular architecture of this organ correlating with its functions. [Int J Res Med Sci 2015; 3(7.000: 1701-1706

  14. Innovation in Accounting Tasks: Empirical Study in Two Professional Groups

    Directory of Open Access Journals (Sweden)

    Célia Cristina da Silva Vicente

    2016-09-01

    Full Text Available The aim of this study is to contribute to the knowledge on innovation in accounting tasks, from the point of view of two professional groups. Its goals are: evaluating the importance given by the professionals to accounting tasks; identifying whether there is convergence between the two professional groups, regarding the importance of the tasks; examining whether there is an association between the professionals’ individual characteristics and the importance they attach to the tasks. Two professional groups were surveyed: 105 financial officers of the top 500 Portuguese companies; and 412 Chartered Accountants. The results obtained allowed us to conclude that the respondents attach more importance to the traditional tasks, linked to the concept of a monetary-oriented accountant, and less importance to the more innovative tasks, related to business strategy; there is no convergence between the two professional groups in terms of the importance of the accountants’ participation in the strategic tasks. Regarding the association between individual characteristics and the level of importance assigned to the accounting tasks, we found an influence of the following characteristics: gender; academic degree of the professionals; and the institution where that degree was obtained.

  15. Hearing aids and tinnitus--an experimental group study.

    Science.gov (United States)

    Melin, L; Scott, B; Lindberg, P; Lyttkens, L

    1987-05-01

    From a waiting list consisting of hearing-impaired patients waiting for hearing aids to be fitted, 39 subjects who at interview also stated that they had tinnitus took part in an experimental group study with the aim of investigating the effect of a hearing aid on tinnitus. No subject had any previous experience of hearing aids. The subjects were randomly allocated to a treatment and a waiting list control group. After an initial interview, the routine programme for the fitting of hearing aids started in the treatment group, while the waiting list control group had to wait for 6 weeks before starting the same hearing aid rehabilitation programme. The hearing aids were fitted exclusively for hearing purposes. As expected, the hearing aids improved the hearing capacity, but they did not reduce tinnitus as recorded on a visual analogue scale. According to information obtained at the final interview, there were significant differences in tinnitus between subjects who used their aid for more than 2 hours daily and those who used it for less than 2 hours. However, the results of scaling (pre- and post-fitting) did not support this finding. The discrepancy between the scaling and interview data is probably due to demand characteristics.

  16. The 10k zCOSMOS : Morphological transformation of galaxies in the Group Environment since z ~1

    NARCIS (Netherlands)

    Kovač, K.; Lilly, S. J.; Knobel, C.; Bolzonella, M.; Iovino, A.; Carollo, C. M.; Scarlata, C.; Sargent, M.; Cucciati, O.; Zamorani, G.; Pozzetti, L.; Tasca, L. A. M.; Scodeggio, M.; Kampczyk, P.; Peng, Y.; Oesch, P.; Zucca, E.; Finoguenov, A.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Mainieri, V.; Renzini, A.; Bardelli, S.; Bongiorno, A.; Caputi, K.; Coppa, G.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Mignoli, M.; Pello, R.; Perez Montero, E.; Ricciardelli, E.; Silverman, J. D.; Tanaka, M.; Tresse, L.; Vergani, D.; Abbas, U.; Bottini, D.; Cappi, A.; Cassata, P.; Cimatti, A.; Fumana, M.; Guzzo, L.; Koekemoer, A. M.; Leauthaud, A.; Maccagni, D.; Marinoni, C.; McCracken, H. J.; Memeo, P.; Meneux, B.; Porciani, C.; Scaramella, R.; Scoville, N. Z.

    2010-01-01

    We study the evolution of galaxies inside and outside of the group environment since z = 1 using a large well-defined set of groups and galaxies from the zCOSMOS-bright redshift survey in the COSMOS field. The fraction of galaxies with early-type morphologies increases monotonically with MB luminosi

  17. Theoretical study of chlordecone and surface groups interaction in an activated carbon model under acidic and neutral conditions.

    Science.gov (United States)

    Gamboa-Carballo, Juan José; Melchor-Rodríguez, Kenia; Hernández-Valdés, Daniel; Enriquez-Victorero, Carlos; Montero-Alejo, Ana Lilian; Gaspard, Sarra; Jáuregui-Haza, Ulises Javier

    2016-04-01

    Activated carbons (ACs) are widely used in the purification of drinking water without almost any knowledge about the adsorption mechanisms of the persistent organic pollutants. Chlordecone (CLD, Kepone) is an organochlorinated synthetic compound that has been used mainly as agricultural insecticide. CLD has been identified and listed as a persistent organic pollutant by the Stockholm Convention. The selection of the best suited AC for this type of contaminants is mainly an empirical and costly process. A theoretical study of the influence of AC surface groups (SGs) on CLD adsorption is done in order to help understanding the process. This may provide a first selection criteria for the preparation of AC with suitable surface properties. A model of AC consisting of a seven membered ring graphene sheet (coronene) with a functional group on the edge was used to evaluate the influence of the SGs over the adsorption. Multiple Minima Hypersurface methodology (MMH) coupled with PM7 semiempirical Hamiltonian was employed in order to study the interactions of the chlordecone with SGs (hydroxyl and carboxyl) at acidic and neutral pH and different hydration conditions. Selected structures were re-optimized using CAM-B3LYP to achieve a well-defined electron density to characterize the interactions by the Quantum Theory of Atoms in Molecules approach. The deprotonated form of surface carboxyl and hydroxyl groups of AC models show the strongest interactions, suggesting a chemical adsorption. An increase in carboxylic SGs content is proposed to enhance CLD adsorption onto AC at neutral pH conditions.

  18. Adolescent girls' views on cosmetic surgery: A focus group study.

    Science.gov (United States)

    Ashikali, Eleni-Marina; Dittmar, Helga; Ayers, Susan

    2016-01-01

    This study examined adolescent girls' views of cosmetic surgery. Seven focus groups were run with girls aged 15-18 years (N = 27). Participants read case studies of women having cosmetic surgery, followed by discussion and exploration of their views. Thematic analysis identified four themes: (1) dissatisfaction with appearance, (2) acceptability of cosmetic surgery, (3) feelings about undergoing cosmetic surgery and (4) cosmetic surgery in the media. Results suggest the acceptability of cosmetic surgery varies according to the reasons for having it and that the media play an important role by normalising surgery and under-representing the risks associated with it.

  19. Bayesian model reduction and empirical Bayes for group (DCM) studies.

    Science.gov (United States)

    Friston, Karl J; Litvak, Vladimir; Oswal, Ashwini; Razi, Adeel; Stephan, Klaas E; van Wijk, Bernadette C M; Ziegler, Gabriel; Zeidman, Peter

    2016-03-01

    This technical note describes some Bayesian procedures for the analysis of group studies that use nonlinear models at the first (within-subject) level - e.g., dynamic causal models - and linear models at subsequent (between-subject) levels. Its focus is on using Bayesian model reduction to finesse the inversion of multiple models of a single dataset or a single (hierarchical or empirical Bayes) model of multiple datasets. These applications of Bayesian model reduction allow one to consider parametric random effects and make inferences about group effects very efficiently (in a few seconds). We provide the relatively straightforward theoretical background to these procedures and illustrate their application using a worked example. This example uses a simulated mismatch negativity study of schizophrenia. We illustrate the robustness of Bayesian model reduction to violations of the (commonly used) Laplace assumption in dynamic causal modelling and show how its recursive application can facilitate both classical and Bayesian inference about group differences. Finally, we consider the application of these empirical Bayesian procedures to classification and prediction.

  20. Studying Problem Solving through Group Discussion in Chat Rooms

    Directory of Open Access Journals (Sweden)

    Inna Kozlova

    2015-11-01

    Full Text Available In the present article we use a chat conversations’ corpus to study the process of resolving language problems. Our corpus includes chat conversations which took place between LSP students engaged in correcting errors in their peers’ summaries. The participants worked in groups and used the Windows Messenger program for communication within the group. Their task also included making use of electronic dictionaries and other reference materials. The conversations’ corpus obtained as a result of this exercise was analyzed holistically for possible indicators of each particular stage of the problem solving process. Later these indicators were validated throughout the entire corpus. Each problem solving process was thus represented as a chain of indicators and acceptability was determined for each error correction. The resulting problem solving chains were used to prove our hypotheses concerning internal and external support in text reproduction.

  1. Theoretical studies on energetic materials bearing pentaflurosulphyl (SF5) groups

    Indian Academy of Sciences (India)

    Li Xiao-Hong; Cui Hong-Ling; Ju Wei-Wei; Li Tong-Wei; Zhang Rui-Zhou; Yong Yong-Liang

    2014-07-01

    Heats of formation (HOF) for a series of energetic materials containing SF5 group were studied by density functional theory. Results show that HOFs increase with the augmention of field effects of substituted groups. Addition of furazan or furoxan ring increases HOF of the energetic materials. All the SF5-containing compounds have densities which are ∼0.19 g/cm3 higher than those containing -NH2 group. S-F bond is the trigger bond for the thermolysis process in the title compounds and bond dissociation energies of the weakest bonds range from 351.1 to 388.3 kJ/mol. Detonation velocities (D) and pressures (P) are evaluated by Kamlet-Jacobs equations with the calculated densities and HOFs. Results show that increasing the amount of furazan rings results in a larger D and P. Considering the detonation performance and thermal stability, eight compounds may be considered as potential candidates for high-energy density materials.

  2. National logistics working groups: A landscape analysis study.

    Science.gov (United States)

    Leab, Dorothy; Schreiber, Benjamin; Kasonde, Musonda; Bessat, Olivia; Bui, Son; Loisel, Carine

    2017-04-19

    Several countries have acknowledged the contributions made by national logistics working groups (NLWG) to ensure equitable access to the expanded program on immunization's (EPI) vaccines against preventable diseases. In order to provide key insights to the United Nations Children's Fund (UNICEF) and the World Health Organization (WHO) supply chain hub - as well as other players, including national EPI - a landscape analysis study was conducted from September 2015 to February 2016. This is a cross-sectional survey taken by 43 countries that combines qualitative and quantitative approaches. Data was collected through a desk review, consultation, interviews, and distance questioning. References and guidance were used to determine and specify the underlying mechanisms of NLWGs. The key findings are:This study has provided a general overview of the status of NLWGs for immunization in various countries. Based on the key insights of the study, technical assistance needs have been identified, and immunization partners will be required to help countries create and reinforce their NLWGs.

  3. A Clinico - Aetiological Study Of Dermatoses In Paediatric Age Group

    Directory of Open Access Journals (Sweden)

    Ghosh Sadhan K

    1995-01-01

    Full Text Available Five hundred patients of the age group 0-12 years were studied for different types of dermatoses. Pyoderma (35.6%, scabies (22.4% and eczema (17.6% were the most common dermatological conditions, followed by molluscum contagiosum (4.6%, popular urticaria with insect bite (4%, vitiligo (3.4%, miliaria (2.8%, nevus (1.6%. Other dermatoses (8% were pityriasis rosea, wart, chicken pox, herpes zoster, acne vulgaris, leprosy, angular stomatitis, pruritus vulvae, psoriasis, candidiasis, condylomatalata, fixed drug relation, tinea capitis and corporis, phrynoderma, alopecia areata, phimosis, geographic tongue, trichotillomania, canitis, pediculosis, hypertrophic scar and pityriasis versicolor.

  4. Density matrix renormalization group numerical study of the kagome antiferromagnet.

    Science.gov (United States)

    Jiang, H C; Weng, Z Y; Sheng, D N

    2008-09-12

    We numerically study the spin-1/2 antiferromagnetic Heisenberg model on the kagome lattice using the density-matrix renormalization group method. We find that the ground state is a magnetically disordered spin liquid, characterized by an exponential decay of spin-spin correlation function in real space and a magnetic structure factor showing system-size independent peaks at commensurate magnetic wave vectors. We obtain a spin triplet excitation gap DeltaE(S=1)=0.055+/-0.005 by extrapolation based on the large size results, and confirm the presence of gapless singlet excitations. The physical nature of such an exotic spin liquid is also discussed.

  5. [Hospital Infection Epidemiology Nederland (ZIEN): from club to study group].

    Science.gov (United States)

    Vandenbroucke-Grauls, C M; Kluytmans, J A; Voss, A

    1997-08-09

    Medical care is increasingly a technical business, and hospitalised patients are more and more susceptible to infections, notably due to the application of aggressive therapies for all kinds of disorders. As a consequence the epidemiology of hospital infections requires serious attention. Following the initiative of some medical microbiologists in the Netherlands, a study group was established to tackle this epidemiology and to initiate relevant research (Working party on Hospital Infections and Epidemiology of the Netherlands; WHEN). Recent subjects include fungemia in hospitalised patients, risk factors for acquiring methicillin-resistant Staphylococcus aureus during a stay abroad, and prevalence of vancomycin-resistant enterococci.

  6. Actions to promote energy efficient electric motors. Motors study group

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, A.T. de [Coimbra Univ. (PT). Inst. of Systems and Robotics (ISR)

    1996-10-01

    Motor electricity consumption is influenced by many factors including: motor efficiency, motor speed controls, power supply quality, harmonics, systems oversizing, distribution network, mechanical transmission system, maintenance practices, load management and cycling, and the efficiency of the end-use device (e.g. fan, pump, etc.). Due to their importance, an overview of these factors is presented in this report. This study also describes the electricity use in the industrial and tertiary sectors and the electricity consumption associated with the different types of electric motors systems in the Member States of the European Union, as well as estimated future evolution until 2010. The studies for individual countries were carried out by the different partners of the motors study group at a previous stage. The study has found that there is a lack of accurate information about the motor electricity consumption, installed motor capacity and the motor market in almost all the European Union countries and only some general statistical sources are available. There is little field data, which is mainly available in Denmark, France, Italy and the Netherlands. Due to this lack of primary information, some common assumptions were made, based on the experience of the members of the study group. This lack of end-use characterisation data shows the need for improvement from the point of view of current knowledge. It is therefore recommended that further research is undertaken to arrive at more accurate figures. These could be the basis for a better understanding for motor use in practice and - as a consequence - for a more precise appraisal of potentials and barriers to energy efficiency. (orig.)

  7. Workers' perception of chemical risks: a focus group study.

    Science.gov (United States)

    Hambach, Ramona; Mairiaux, Philippe; François, Guido; Braeckman, Lutgart; Balsat, Alain; Van Hal, Guido; Vandoorne, Chantal; Van Royen, Paul; van Sprundel, Marc

    2011-02-01

    Workers' perceptions with respect to health and safety at work are rarely taken into account when considering the development of prevention programs. The aim of this study was to explore workers' perceptions of chemical risks at the workplace, in order to investigate the prerequisites for a workplace health program. A qualitative study was conducted involving seven focus groups of 5-10 participants (blue-collar workers) each. All groups were homogeneous in terms of sex, work status, language, and company membership. Results showed that several factors have an important influence on workers' perception of chemical risks. Workers assess risks by means of both sensory and empirical diagnosis and are concerned about the long-term health consequences. They perceive the threat of chemical risks as high. Despite this, they are resigned to accepting the risks. Existing formal sources of information are rarely consulted because they are judged to be difficult to understand and not user friendly. Instead, workers tend to obtain information from informal sources. Communication problems with and lack of trust in prevention advisers and hierarchy are frequently mentioned. Workers feel that their specific knowledge of their working conditions and their proposals for practical, cost-effective solutions to improve health and safety at the workplace are insufficiently taken into account. The use of focus groups yielded a useful insight into workers' perceptions of chemical risks. Our findings suggest that training programs for prevention advisers should include topics such as understanding of workers' perceptions, usefulness of a participatory approach, and communication and education skills. © 2010 Society for Risk Analysis.

  8. Group hypnotherapy versus group relaxation for smoking cessation: an RCT study protocol

    Directory of Open Access Journals (Sweden)

    Dickson-Spillmann Maria

    2012-04-01

    Full Text Available Abstract Background A significant number of smokers would like to stop smoking. Despite the demonstrated efficacy of pharmacological smoking cessation treatments, many smokers are unwilling to use them; however, they are inclined to try alternative methods. Hypnosis has a long-standing reputation in smoking cessation therapy, but its efficacy has not been scientifically proven. We designed this randomised controlled trial to evaluate the effects of group hypnosis as a method for smoking cessation, and we will compare the results of group hypnosis with group relaxation. Methods/Design This is a randomised controlled trial (RCT to compare the efficacy of a single session of hypnosis with that of relaxation performed in groups of 8-15 smokers. We intend to include at least 220 participants in our trial. The inclusion criteria include smoking at least 5 cigarettes per day, not using other cessation methods and being willing to quit smoking. The intervention is performed by a trained hypnotist/relaxation therapist. Both groups first receive 40 min of mental preparation that is based on motivational interviewing. Then, a state of deep relaxation is induced in the hypnosis condition, and superficial relaxation is induced in the control condition. Suggestions are made in the hypnosis condition that aim to switch the mental self-image of the participants from that of smokers to that of non-smokers. Each intervention lasts for 40 min. The participants also complete questionnaires that assess their smoking status and symptoms of depression and anxiety at baseline, 2 weeks and 6 months post-intervention. In addition, saliva samples are collected to assess cotinine levels at baseline and at 6 months post-intervention. We also assess nicotine withdrawal symptoms at 2 weeks post-intervention. Discussion To the best of our knowledge, this RCT is the first to test the efficacy of group hypnosis versus group relaxation. Issues requiring discussion in the outcome

  9. The Life Design Group: A Case Study Vignette in Group Career Construction Counseling

    Science.gov (United States)

    Barclay, Susan R.; Stoltz, Kevin B.

    2016-01-01

    Providing cost efficient, yet effective, student services, including career services, is a critical component in higher education. Career services must include the perspectives of the 21st-century work place. We advocate for the delivery of career development services in a group format using a narrative approach to career counseling with college…

  10. An ethnography of reading in a spiritist study group

    Directory of Open Access Journals (Sweden)

    Bernardo Lewgoy

    Full Text Available As a religion, Kardecism confers fundamental importance to the study of its own body of literature, understood as the complement to religious revelation. Based upon ethnographic research in a traditional middle-class Kardecist centre in Porto Alegre, this article examines some ways through which the Kardecists, structured in small groups, interact with this written tradition. The group is fundamental in forming a spiritist identity for two reasons: firstly, it delimits internal alliances, whether or not these are translated into differences in doctrinal views. Secondly, it is one of the spaces in which the spiritist orator is formed by learning to make use of formulas extracted from a specific repertoire. Inspired by the discussions on orality and literacy and by the recent proposal for an ethnography of reading (Boyarin 1993, I aim to show that, if the spiritist speech is constructed as orality supported by texts, there are also very important informal dimensions to be considered which contextualize and actualize these group’s relation with sacred texts.

  11. Young Adults, Technology, and Weight Loss: A Focus Group Study

    Directory of Open Access Journals (Sweden)

    Janna Stephens

    2015-01-01

    Full Text Available Overweight and obesity are a major concern in young adults. Technology has been integrated into many weight loss interventions; however little is known about the use of this technology in young adults. The purpose of this study was to explore through focus group sessions the opinions of young adults on the use of technology for weight loss. A total of 17 young adults, between 18 and 25 years of age, participated in three focus group sessions. Major results indicated that young adults have very little knowledge on the use of Smartphone technology for weight loss but would like to use this type of technology to help them lose weight. Results also indicated that young adults struggle to make healthy food choices and have priorities that outweigh exercise and they need support and guidance to make better decisions. In conclusion, young adults would be open to using Smartphone technology for weight loss but also need feedback and guidance to help make healthy decisions.

  12. [Streptococcal toxic shock syndrome or Kawasaki disease? Two case studies of children with group A streptococcal pneumonia empyema].

    Science.gov (United States)

    Bosland, A; Arlaud, K; Rousset-Rouvière, C; Fouilloux, V; Paut, O; Dubus, J-C; Bosdure, E

    2011-12-01

    We report 2 cases of children with group A streptococcus pyogenes pleuropneumonia, in one child associated with Kawasaki disease and in the other with streptococcal toxic shock syndrome. These 2 features, with theoretically well-defined clinical and biological criteria, are difficult to differentiate in clinical practice, however, likely due to their pathophysiological links. In case of clinical doubt, an echocardiography needs to be performed to search for coronary involvement and treatment including intravenous immunoglobulins, and an antibiotic with an anti-toxin effect such as clindamycin has to be started early.

  13. A case study of a Postgraduate student's group expe

    African Journals Online (AJOL)

    higher education contexts especially in one year masters degree in a foreign country ... physical attractiveness; perceived ability and competence; attitude and ... developed amongst the group members and this cohesion helps the group to.

  14. Virtual Gaming Simulation in Nursing Education: A Focus Group Study.

    Science.gov (United States)

    Verkuyl, Margaret; Hughes, Michelle; Tsui, Joyce; Betts, Lorraine; St-Amant, Oona; Lapum, Jennifer L

    2017-05-01

    The use of serious gaming in a virtual world is a novel pedagogical approach in nursing education. A virtual gaming simulation was implemented in a health assessment class that focused on mental health and interpersonal violence. The study's purpose was to explore students' experiences of the virtual gaming simulation. Three focus groups were conducted with a convenience sample of 20 first-year nursing students after they completed the virtual gaming simulation. Analysis yielded five themes: (a) Experiential Learning, (b) The Learning Process, (c) Personal Versus Professional, (d) Self-Efficacy, and (e) Knowledge. Virtual gaming simulation can provide experiential learning opportunities that promote engagement and allow learners to acquire and apply new knowledge while practicing skills in a safe and realistic environment. [J Nurs Educ. 2017;56(5):274-280.]. Copyright 2017, SLACK Incorporated.

  15. Teaching Astronomy in Extracurricular Study Groups of Armenia

    Science.gov (United States)

    Khachatryan, Mher; Grigoryan, Avetik

    2016-12-01

    The report presents the history of activity of Extracurricular Study Groups of Ar¬menia teaching astronomy and related subjects. It mainly refers to the Aerospace Club founded in 1988, which has long been acting as an officially unre¬gis¬tered, but efficiently performing non-governmental organization - Armenian Youth Ae¬ro¬space Society. The Club teaches, provides a truly scientific view of the world, advocates astronomy and other scientific and technical areas, provides interesting lectures and ar¬ticles to schools and mass media, arranges seminars and meetings with renowned experts, publishes scientific ar¬ticles, manuals, books, puts forward important scientific and techno-logical problems and offer students to work together on them, seek for solutions and develop possible appli¬ca¬tions. All this is aimed at maintaining and further development of leading positions of Armenia's scientific potential, particularly in astronomy.

  16. Accountable Metadata-Hiding Escrow: A Group Signature Case Study

    Directory of Open Access Journals (Sweden)

    Kohlweiss Markulf

    2015-06-01

    Full Text Available A common approach to demands for lawful access to encrypted data is to allow a trusted third party (TTP to gain access to private data. However, there is no way to verify that this trust is well placed as the TTP may open all messages indiscriminately. Moreover, existing approaches do not scale well when, in addition to the content of the conversation, one wishes to hide one’s identity. Given the importance of metadata this is a major problem. We propose a new approach in which users can retroactively verify cryptographically whether they were wiretapped. As a case study, we propose a new signature scheme that can act as an accountable replacement for group signatures, accountable forward and backward tracing signatures.

  17. Report of the Study Group on Assessment and Evaluation

    CERN Document Server

    Crouch, R; Netter, K; Crouch, Richard; Gaizuaskas, Robert; Netter, Klaus

    1996-01-01

    This is an interim report discussing possible guidelines for the assessment and evaluation of projects developing speech and language systems. It was prepared at the request of the European Commission DG XIII by an ad hoc study group, and is now being made available in the form in which it was submitted to the Commission. However, the report is not an official European Commission document, and does not reflect European Commission policy, official or otherwise. After a discussion of terminology, the report focusses on combining user-centred and technology-centred assessment, and on how meaningful comparisons can be made of a variety of systems performing different tasks for different domains. The report outlines the kind of infra-structure that might be required to support comparative assessment and evaluation of heterogenous projects, and also the results of a questionnaire concerning different approaches to evaluation.

  18. The narrow range of perceived predation: a 19 group study

    Directory of Open Access Journals (Sweden)

    Olivier Mesly

    2013-05-01

    Full Text Available This paper rests largely on the works of Mesly (1999 to 2012. It argues that the phenomenon of perceived predation as a functional behavioural phenomenon is subjected to certain limits, a finding based on studies performed on 19 different groups spread over a four-year span. It also finds a constant of k = 1.3 which reflects the invariant nature of perceived predation. These findings add to the theory of financial predation which stipulates that financial predators operate below the limits of detection pertaining to their customers (and market regulators. They are experts at minimizing the perception that clients could have that they are after their money, causing them financial harm, by surprise (perceived predation. Understanding the narrow range in which financial predators operate is setting the grounds to offer better protection to investors and to implementing better control and punitive measures.

  19. Introducing Semantic Cohesion Analysis: A Study of Group Talk.

    Science.gov (United States)

    Friedlander, Myrna L.; And Others

    1985-01-01

    Cohesive talk was observed over time and across psychotherapy groups led by self-disclosing or nondisclosing therapists. Despite individual therapist differences, the nondisclosing groups showed more cohesive interactions throughout therapy. No differences were observed in clients' perceptions of therapists or their attraction to the group.…

  20. Gout in immigrant groups: a cohort study in Sweden.

    Science.gov (United States)

    Wändell, Per; Carlsson, Axel C; Li, Xinjun; Gasevic, Danijela; Ärnlöv, Johan; Holzmann, Martin J; Sundquist, Jan; Sundquist, Kristina

    2017-01-13

    Our aim was to study the association between country of birth and incidence of gout in different immigrant groups in Sweden. The study population included the whole population of Sweden. Gout was defined as having at least one registered diagnosis in the National Patient Register. The association between incidence of gout and country of birth was assessed by Cox regression, with hazard ratios (HRs) and 95% confidence intervals (95% CI), using Swedish-born individuals as referents. All models were conducted in both men and women, and the full model was adjusted for age, place of residence in Sweden, educational level, marital status, neighbourhood socio-economic status and co-morbidities. The risk of gout varied by country of origin, with highest estimates, compared to Swedish born, in fully adjusted models among men from Iraq (HR 1.82, 95% CI 1.54-2.16), and Russia (HR 1.69, 95% CI 1.26-2.27), and also high among men from Austria, Poland, Africa and Asian countries outside the Middle East; and among women from Africa (HR 2.23, 95% CI 1.50-3.31), Hungary (HR 1.98, 95% CI 1.45-2.71), Iraq (HR 1.76, 95% CI 1.13-2.74) and Austria (HR 1.70, 95% CI 1.07-2.70), and also high among women from Poland. The risk of gout was lower among men from Greece, Spain, Nordic countries (except Finland) and Latin America and among women from Southern Europe, compared to their Swedish counterparts. The increased risk of gout among several immigrant groups is likely explained by a high cardio-metabolic risk factor pattern needing attention.

  1. Gender-based education during clerkships: a focus group study

    Directory of Open Access Journals (Sweden)

    van Leerdam L

    2014-02-01

    Full Text Available Lotte van Leerdam, Lianne Rietveld, Doreth Teunissen, Antoine Lagro-JanssenDepartment of Primary and Community Care, Gender and Women's Health, Radboud University Medical Center, Nijmegen, The NetherlandsObjectives: One of the goals of the medical master's degree is for a student to become a gender-sensitive doctor by applying knowledge of gender differences in practice. This study aims to investigate, from the students’ perspective, whether gender medicine has been taught in daily practice during clerkship.Methods: A focus group study was conducted among 29 medical students from Radboud University, Nijmegen, The Netherlands, who had just finished either their internal medicine or surgical clerkships. Data were analyzed in line with the principles of constant comparative analysis.Results: Four focus groups were conducted with 29 participating students. Clinical teachers barely discuss gender differences during students’ clerkships. The students mentioned three main explanatory themes: insufficient knowledge; unawareness; and minor impact. As a result, students feel that they have insufficient competencies to become gender-sensitive doctors.Conclusion: Medical students at our institution perceive that they have received limited exposure to gender-based education after completing two key clinical clerkships. All students feel that they have insufficient knowledge to become gender-sensitive doctors. They suppose that their clinical teachers have insufficient knowledge regarding gender sensitivity, are unaware of gender differences, and the students had the impression that gender is not regarded as an important issue. We suggest that the medical faculty should encourage clinical teachers to improve their knowledge and awareness of gender issues.Keywords: medical education, clerkship, gender, hidden curriculum, clinical teachers

  2. Music during after-death care: a focus group study.

    Science.gov (United States)

    Holm, Marianne S; Fålun, Nina; Gjengedal, Eva; Norekvål, Tone M

    2012-01-01

    The intensive care unit (ICU) is not only a place to recover from injuries incurred during accidents and from serious illness. For many patients, it is also a place where they might die. Nursing care does not stop when a patient dies; rather, it continues with the care of the deceased and with family support. The aims of this study were (1) to explore the experiences and attitudes of nurses towards the use of ambient music in the ICU during after-death care and (2) to describe the feedback nurses received from relatives when music was used during the viewing. A qualitative design employing focus group interviews was used. Three focus group interviews with 15 nurses were conducted. All the interviews were audiotaped, transcribed verbatim and analysed using qualitative content analysis. Six main categories of attitudes emerged from the analysis: (1) different attitudes among nurses towards the use of music; (2) music affects the atmosphere; (3) music affects emotions; (4) use of music was situational; (5) special choice of music and (6) positive feedback from the bereaved. This study demonstrates that music might be helpful for nurses during after-death care as well as for the care of the relatives. Including ambient music in an after-death care programme can help nurses show respect for the deceased as the body is being prepared. Music played during the viewing may be a way of helping relatives in their time of grieving. It may ease the situation by making that event special and memorable. However, standardizing this intervention does not seem appropriate. Rather, the individual nurse and the family must decide whether music is to be used in a particular situation. © 2012 The Authors. Nursing in Critical Care © 2012 British Association of Critical Care Nurses.

  3. Focus Group Study Exploring Factors Related to Frequent Sickness Absence.

    Directory of Open Access Journals (Sweden)

    Annette Notenbomer

    Full Text Available Research investigating frequent sickness absence (3 or more episodes per year is scarce and qualitative research from the perspective of frequent absentees themselves is lacking. The aim of the current study is to explore awareness, determinants of and solutions to frequent sickness absence from the perspective of frequent absentees themselves.We performed a qualitative study of 3 focus group discussions involving a total of 15 frequent absentees. Focus group discussions were audiotaped and transcribed verbatim. Results were analyzed with the Graneheim method using the Job Demands Resources (JD-R model as theoretical framework.Many participants were not aware of their frequent sickness absence and the risk of future long-term sickness absence. As determinants, participants mentioned job demands, job resources, home demands, poor health, chronic illness, unhealthy lifestyles, and diminished feeling of responsibility to attend work in cases of low job resources. Managing these factors and improving communication (skills were regarded as solutions to reduce frequent sickness absence.The JD-R model provided a framework for determinants of and solutions to frequent sickness absence. Additional determinants were poor health, chronic illness, unhealthy lifestyles, and diminished feeling of responsibility to attend work in cases of low job resources. Frequent sickness absence should be regarded as a signal that something is wrong. Managers, supervisors, and occupational health care providers should advise and support frequent absentees to accommodate job demands, increase both job and personal resources, and improve health rather than express disapproval of frequent sickness absence and apply pressure regarding work attendance.

  4. Occupational therapists' perceptions of gender - a focus group study.

    Science.gov (United States)

    Liedberg, Gunilla M; Björk, Mathilda; Hensing, Gunnel

    2010-10-01

    Women and men are shaped over the courses of their lives by culture, society and human interaction according to the gender system. Cultural influences on individuals' social roles and environment are described in occupational therapy literature, but not specifically from a gender perspective. The purpose of this qualitative study was to explore how a sample of occupational therapists perceives the 'gender' concept. Four focus group interviews with 17 occupational therapists were conducted. The opening question was: 'How do you reflect on the encounter with a client depending on whether it is a man or a woman?' The transcribed interviews were analysed and two main themes emerged: 'the concept of gender is tacit in occupational therapy' and 'client encounters'. The occupational therapists expressed limited theoretical knowledge of 'gender'. Furthermore, the occupational therapists seemed to be 'doing gender' in their encounters with the clients. For example, in their assessment of the client, they focussed their questions on different spheres: with female clients, on the household and family; with male clients, on their paid work. This study demonstrated that occupational therapists were unaware of the possibility that they were 'doing gender' in their encounters with clients. There is a need to increase occupational therapists' awareness of their own behaviour of 'doing gender'. Furthermore, there is a need to investigate whether gendered perceptions will shorten or lengthen a rehabilitation period and affect the chosen interventions, and in the end, the outcome for the clients. © 2010 The Authors. Australian Occupational Therapy Journal © 2010 Australian Association of Occupational Therapists.

  5. Collective Talent : A Study of Improvisational Group Performance in Music

    OpenAIRE

    Jong, de, F.

    2006-01-01

    Improvised music performance offers remarkable and dramatic examples of the talented ways in which group members can interact and inspire each other. Such musical sessions can serve as examples of improvised performance of groups in general. This thesis reports on ways of initiating and supporting talented group improvisation. It addresses the question which interface is needed to generate collectives with collective talent. Inspired by Pask's Conversation Theory, the author has developed a t...

  6. Recent advances in the study of the Equivariant Brauer Group

    CERN Document Server

    Bouwknegt, Peter; Ratnam, Rishni

    2011-01-01

    In this paper we outline a recent construction of a Chern-Weil isomorphism for the equivariant Brauer group of $\\mathbb R^n$ actions on a principal torus bundle, where the target for this isomorphism is a "dimensionally reduced" \\vCech cohomology group. Using this latter group, we demonstrate how to extend the induced algebra construction to algebras with a non-trivial bundle as their spectrum.

  7. Geochemical Study of Lichens in Tatun Volcano Group, North Taiwan

    Science.gov (United States)

    Kuan, Ssu-Yu

    2015-04-01

    Tatun Volcano Group (TVG) is located in the northwest of Taipei, the capital of Taiwan. Although the last activity was 200000 years ago, it is critical to monitor TVG because it is nearby metropolitan area. This study is part of the monitoring program and attempts to observe the geochemical relationship between lichen and volcanic gas. Lichens have been extensively used for monitoring atmospheric quality. Lichen can live in critical environments and can accumulate metals from atmosphere due to lack of excretion mechanism. Moreover, lichen can live long and growth in a low rate; therefore, lichen geochemistry can represent an average in a long term manner. In TVG, fruticose lichen can be seldom found due to the high concentration of SO2 in the atmosphere. However, foliose lichen and crustose lichen are not rare in the study area. In this study, lichens were collected from TVG and Nan-ao Trail which is in non-volcanic area. The cations were measured by ICP-MS. The geochemical results were analyzed by principal components analysis (PCA). It shows that there is no significant difference among non-volcanic lichens and the non-volcanic lichens are located at an end-member of two distinct trends. It is believed that the non-volcanic lichens indicate a geochemical baseline in north Taiwan and two trends may represent the mixing between two different types of volcanic gases in TVG and geochemical baseline. In this study, rare earth elements (REEs) were also measured. The results of non-volcanic and TVG lichens were normalized by North America Shale and TVG andesite, respectively. Both obtain a flat REE pattern, which confirm that TVG lichens receive metals from volcanic origin and non-volcanic lichens give information of background geochemistry in north Taiwan. In addition, a middle REE enrichment and distinct Ce negative anomaly can be observed. According to the previous studies, middle REE enrichment may be achieved by the selected adsorption of middle REEs by organic

  8. Collective Talent : A Study of Improvisational Group Performance in Music

    NARCIS (Netherlands)

    Jong, de Jacqueline B.

    2006-01-01

    Improvised music performance offers remarkable and dramatic examples of the talented ways in which group members can interact and inspire each other. Such musical sessions can serve as examples of improvised performance of groups in general. This thesis reports on ways of initiating and supporting t

  9. Technology User Groups and Early Childhood Education: A Preliminary Study

    Science.gov (United States)

    Parette, Howard P.; Hourcade, Jack J.; Blum, Craig; Watts, Emily H.; Stoner, Julia B.; Wojcik, Brian W.; Chrismore, Shannon B.

    2013-01-01

    This article presents a preliminary examination of the potential of Technology User Groups as a professional development venue for early childhood education professionals in developing operational and functional competence in using hardware and software components of a Technology toolkit. Technology user groups are composed of varying numbers of…

  10. Collective Talent : A Study of Improvisational Group Performance in Music

    NARCIS (Netherlands)

    Jong, de Jacqueline B.

    2006-01-01

    Improvised music performance offers remarkable and dramatic examples of the talented ways in which group members can interact and inspire each other. Such musical sessions can serve as examples of improvised performance of groups in general. This thesis reports on ways of initiating and supporting

  11. Collective Talent : A Study of Improvisational Group Performance in Music

    NARCIS (Netherlands)

    Jong, de Jacqueline B.

    2006-01-01

    Improvised music performance offers remarkable and dramatic examples of the talented ways in which group members can interact and inspire each other. Such musical sessions can serve as examples of improvised performance of groups in general. This thesis reports on ways of initiating and supporting t

  12. Dissipative two-electron transfer: A numerical renormalization group study

    Science.gov (United States)

    Tornow, Sabine; Bulla, Ralf; Anders, Frithjof B.; Nitzan, Abraham

    2008-07-01

    We investigate nonequilibrium two-electron transfer in a model redox system represented by a two-site extended Hubbard model and embedded in a dissipative environment. The influence of the electron-electron interactions and the coupling to a dissipative bosonic bath on the electron transfer is studied in different temperature regimes. At high temperatures, Marcus transfer rates are evaluated, and at low temperatures, we calculate equilibrium and nonequilibrium population probabilities of the donor and acceptor with the nonperturbative numerical renormalization group approach. We obtain the nonequilibrium dynamics of the system prepared in an initial state of two electrons at the donor site and identify conditions under which the electron transfer involves one concerted two-electron step or two sequential single-electron steps. The rates of the sequential transfer depend nonmonotonically on the difference between the intersite and on-site Coulomb interaction, which become renormalized in the presence of the bosonic bath. If this difference is much larger than the hopping matrix element, the temperature as well as the reorganization energy, simultaneous transfer of both electrons between donor and acceptor can be observed.

  13. Operating theatre nurses' perceptions of competence: a focus group study.

    Science.gov (United States)

    Gillespie, Brigid M; Chaboyer, Wendy; Wallis, Marianne; Chang, Hsiao-Yun Annie; Werder, Helen

    2009-05-01

    This paper is a report of a study exploring nurses' perceptions of the components of competence in the operating theatre. Competency Standards for operating theatre practice are used in some countries to guide clinical and professional behaviours. The need for competence assessment has been enshrined, but the conceptualization and agreement about what signifies competence in Operating Theatre has been lacking. Three focus groups were conducted with 27 operating theatre nurses in three major metropolitan hospitals in Queensland, Australia. Interviews were audio taped and field notes were taken. Data were collected during 2008. Thematic analysis was performed. From the analysis of the textual data, three themes were identified: 'coalescence of theoretical, practical, situational and aesthetic knowledge within a technocratic environment'; 'the importance of highly developed communication skills among teams of divergent personalities and situations'; and 'managing and coordinating the flow of the list'. These findings have identified that competence in respect to components of knowledge, teamwork and communication, and the ability to coordinate and manage are important and should be incorporated in operating theatre Competency Standards. Additionally, findings may assist in the development of an instrument to measure operating nurses' perceived competence.

  14. Profiles in Successful Group Piano for Children: A Collective Case Study of Children's Group-Piano Lessons

    Science.gov (United States)

    Pike, Pamela D.

    2013-01-01

    The purpose of this collective case study was to explore the best practices in beginning group-piano instruction. Four beginning and intermediate groups of piano students (N =20) were observed. Data were triangulated through in-class observation of students and teachers, teacher interviews and student questionnaires. The master teachers…

  15. Profiles in Successful Group Piano for Children: A Collective Case Study of Children's Group-Piano Lessons

    Science.gov (United States)

    Pike, Pamela D.

    2013-01-01

    The purpose of this collective case study was to explore the best practices in beginning group-piano instruction. Four beginning and intermediate groups of piano students (N =20) were observed. Data were triangulated through in-class observation of students and teachers, teacher interviews and student questionnaires. The master teachers…

  16. Profiles in Successful Group Piano for Children: A Collective Case Study of Children's Group-Piano Lessons

    Science.gov (United States)

    Pike, Pamela D.

    2013-01-01

    The purpose of this collective case study was to explore the best practices in beginning group-piano instruction. Four beginning and intermediate groups of piano students (N =20) were observed. Data were triangulated through in-class observation of students and teachers, teacher interviews and student questionnaires. The master teachers…

  17. Performance study on Gossip-based group key distribution protocal

    Institute of Scientific and Technical Information of China (English)

    Yao Yan; Ma Jiaqing; Zhong Yiping; Zhang Shiyong

    2006-01-01

    Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast protocol can not deal with them fully. Gossip-based group key distribution idea for wide-area dissemination was provided. It is based on an gossip-based loss recovery control mechanism. It can provide a probabilistic reliable guarantee for a information dissemination to reach every group member, which can achieve scalability and reliability. To achieve full reliability, three layers protocol model in group key distribution was provided. One is best effect layer, which provides unreliable dissemination. Other is gossip-based loss recovery layer, which provides probabilistic reliable guarantee. Last is vsync-based layer, which provide deterministic loss recovery. We integrate probabilistic loss recovery method with deterministic one. The model possess scalability that probabilistic method has and full reliability prosthesis by vsync-based. To evaluate the effectiveness of gossip technique in scalable and reliable multicast protocols. We have compared gossip protocol with other reliable multicast protocols. Experimental result shows that gossip protocol has better scalability than other.

  18. Studying the Stellar Populations of the Local Group with VLT

    Science.gov (United States)

    Tolstoy, Eline

    The best chance we have to understand star formation and how it proceeds in the Universe is going to come from detailed studies of the numerous different environments found within the Local Group (LG). Present day star formation in our Galaxy occurs exclusively in metal rich environments (Z ˜ Z_⊙), so if we want to study how low metallicity stars form (and thus understand observations of galaxies at high-redshift) we have to look beyond our Galaxy, to the smallest star forming dwarf galaxies, which can have extremely low metallicities (Z ˜ 0.02-0.05Z_⊙). Of course in its entirety a stellar population always contains the complete details of the star formation history of a galaxy, however this information is often hard to disentangle retroactively. We also have much to learn from the Magellanic Clouds (Z ˜ 0.1- 0.3Z_⊙), although because they are undergoing interactions with our Galaxy and each other their evolutionary picture and its general applicability less obvious. In our LG there are also a number of "remnants", or galaxies which which currently do not form stars (e.g. the dSph, such as Carina, Leo I, Ursa Minor, etc..). It is not straight forward to draw parallels between galaxies which are forming stars and those which aren't. This is of course because star formation has such a dramatic impact upon a galaxy, and alternative methods have to be used to make the most basic of comparisons of properties (e.g. metallicity, mass, luminosity evolution). It is necessary to put all the dwarf galaxies into a global picture if we are to draw meaningful conclusions about their star formation properties (e.g. Ferrara & Tolstoy 1999). Many of the small LG galaxies contain direct evidence of complicated star formation histories (e.g. Smecker-Hane et al. 1994; Tolstoy et al. 1998; Gallart et al. 1999), which suggests that star formation patterns can change dramatically over long time scales. This kind of evolutionary behaviour can have a dramatic impact upon the

  19. What about N? A methodological study of sample-size reporting in focus group studies

    Directory of Open Access Journals (Sweden)

    Glenton Claire

    2011-03-01

    Full Text Available Abstract Background Focus group studies are increasingly published in health related journals, but we know little about how researchers use this method, particularly how they determine the number of focus groups to conduct. The methodological literature commonly advises researchers to follow principles of data saturation, although practical advise on how to do this is lacking. Our objectives were firstly, to describe the current status of sample size in focus group studies reported in health journals. Secondly, to assess whether and how researchers explain the number of focus groups they carry out. Methods We searched PubMed for studies that had used focus groups and that had been published in open access journals during 2008, and extracted data on the number of focus groups and on any explanation authors gave for this number. We also did a qualitative assessment of the papers with regard to how number of groups was explained and discussed. Results We identified 220 papers published in 117 journals. In these papers insufficient reporting of sample sizes was common. The number of focus groups conducted varied greatly (mean 8.4, median 5, range 1 to 96. Thirty seven (17% studies attempted to explain the number of groups. Six studies referred to rules of thumb in the literature, three stated that they were unable to organize more groups for practical reasons, while 28 studies stated that they had reached a point of saturation. Among those stating that they had reached a point of saturation, several appeared not to have followed principles from grounded theory where data collection and analysis is an iterative process until saturation is reached. Studies with high numbers of focus groups did not offer explanations for number of groups. Too much data as a study weakness was not an issue discussed in any of the reviewed papers. Conclusions Based on these findings we suggest that journals adopt more stringent requirements for focus group method

  20. A Study on Signal Group Processing of AUTOSAR COM Module

    Science.gov (United States)

    Lee, Jeong-Hwan; Hwang, Hyun Yong; Han, Tae Man; Ahn, Yong Hak

    2013-06-01

    In vehicle, there are many ECU(Electronic Control Unit)s, and ECUs are connected to networks such as CAN, LIN, FlexRay, and so on. AUTOSAR COM(Communication) which is a software platform of AUTOSAR(AUTomotive Open System ARchitecture) in the international industry standards of automotive electronic software processes signals and signal groups for data communications between ECUs. Real-time and reliability are very important for data communications in the vehicle. Therefore, in this paper, we analyze functions of signals and signal groups used in COM, and represent that functions of signal group are more efficient than signals in real-time data synchronization and network resource usage between the sender and receiver.

  1. Functional renormalization group study of fluctuation effects in fermionic superfluids

    Energy Technology Data Exchange (ETDEWEB)

    Eberlein, Andreas

    2013-03-22

    This thesis is concerned with ground state properties of two-dimensional fermionic superfluids. In such systems, fluctuation effects are particularly strong and lead for example to a renormalization of the order parameter and to infrared singularities. In the first part of this thesis, the fermionic two-particle vertex is analysed and the fermionic renormalization group is used to derive flow equations for a decomposition of the vertex in charge, magnetic and pairing channels. In the second part, the channel-decomposition scheme is applied to various model systems. In the superfluid state, the fermionic two-particle vertex develops rich and singular dependences on momentum and frequency. After simplifying its structure by exploiting symmetries, a parametrization of the vertex in terms of boson-exchange interactions in the particle-hole and particle-particle channels is formulated, which provides an efficient description of the singular momentum and frequency dependences. Based on this decomposition of the vertex, flow equations for the effective interactions are derived on one- and two-loop level, extending existing channel-decomposition schemes to (i) the description of symmetry breaking in the Cooper channel and (ii) the inclusion of those two-loop renormalization contributions to the vertex that are neglected in the Katanin scheme. In the second part, the superfluid ground state of various model systems is studied using the channel-decomposition scheme for the vertex and the flow equations. A reduced model with interactions in the pairing and forward scattering channels is solved exactly, yielding insights into the singularity structure of the vertex. For the attractive Hubbard model at weak coupling, the momentum and frequency dependence of the two-particle vertex and the frequency dependence of the self-energy are determined on one- and two-loop level. Results for the suppression of the superfluid gap by fluctuations are in good agreement with the literature

  2. Enhancing Student Engagement: A Group Case Study Approach

    Science.gov (United States)

    Taneja, Aakash

    2014-01-01

    Computing professionals work in groups and collaborate with individuals having diverse backgrounds and behaviors. The Accreditation Board for Engineering and Technology (ABET) characterizes that a computing program must enable students to attain the ability to analyze a problem, design and evaluate a solution, and work effectively on teams to…

  3. The use of a well-defined surface organometallic complex as a probe molecule: [(SiO)TaVCl2Me2] shows different isolated silanol sites on the silica surface

    KAUST Repository

    Chen, Yin

    2014-01-01

    TaVCl2Me3 reacts with silica(700) and produces two different [(SiO)TaVCl2Me2] surface organometallic species, suggesting a heterogeneity of the highly dehydroxylated silica surface, which was studied with a combined experimental and theoretical approach. This journal is © the Partner Organisations 2014.

  4. Group schema therapy for eating disorders: a pilot study.

    Science.gov (United States)

    Simpson, Susan G; Morrow, Emma; van Vreeswijk, Michiel; Reid, Caroline

    2010-01-01

    This paper describes the use of Group Schema Therapy for Eating Disorders (ST-E-g) in a case series of eight participants with chronic eating disorders and high levels of co-morbidity. Treatment was comprised of 20 sessions which included cognitive, experiential, and interpersonal strategies, with an emphasis on behavioral change. Specific schema-based strategies focused on bodily felt-sense and body-image, as well as emotional regulation skills. Six attended until end of treatment, two dropped-out at mid-treatment. Eating disorder severity, global schema severity, shame, and anxiety levels were reduced between pre- and post-therapy, with a large effect size at follow-up. Clinically significant improvement in eating severity was found in four out of six completers. Group completers showed a mean reduction in schema severity of 43% at post-treatment, and 59% at follow-up. By follow-up, all completers had achieved over 60% improvement in schema severity. Self-report feedback suggests that group factors may catalyze the change process in schema therapy by increasing perceptions of support and encouragement to take risks and try out new behaviors, whilst providing a de-stigmatizing and de-shaming therapeutic experience.

  5. Group Schema Therapy for Eating Disorders: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Susan G Simpson

    2010-11-01

    Full Text Available This paper describes the use of Group Schema Therapy for Eating Disorders (ST-E-g in a case-series of eight participants with chronic eating disorders and high levels of co-morbidity. Treatment was comprised of 20 sessions which included cognitive, experiential and interpersonal strategies, with an emphasis on behavioural change. Specific schema-based strategies focused on bodily felt-sense and body-image, as well as emotional regulation skills. Six attended until end of treatment, two dropped-out at mid-treatment. Eating disorder severity, global schema severity, shame and anxiety levels were reduced between pre- and post therapy, with a large effect size at follow-up. Clinically significant improvement in eating severity was found in four out of six completers. Group completers showed a mean reduction in schema severity of 43% at post-treatment, and 59% at follow-up. By follow-up, all completers had achieved over 60% improvement in schema severity. Self-report feedback suggests that group factors may catalyze the change process in schema therapy by increasing perceptions of support and encouragement to take risks and try out new behaviours, whilst providing a de-stigmatising and de-shaming therapeutic experience.

  6. The effects of group 1 versus group 2 carbapenems on imipenem-resistant Pseudomonas aeruginosa: an ecological study.

    Science.gov (United States)

    Carmeli, Yehuda; Lidji, Shiri Klarfeld; Shabtai, Esther; Navon-Venezia, Shiri; Schwaber, Mitchell J

    2011-07-01

    Use of the group 2 carbapenems, imipenem and meropenem, may lead to emergence of Pseudomonas aeruginosa resistance. The group 1 carbapenem ertapenem has limited activity against P. aeruginosa and is not associated with imipenem-resistant P. aeruginosa (IMP-R PA) in vitro. This retrospective, group-level, longitudinal study collected patient, antibiotic use, and resistance data from 2001 to 2005 using a hospital database containing information on 9 medical wards. A longitudinal data time series analysis was done to evaluate the association between carbapenem use (defined daily doses, or DDDs) and IMP-R PA. A total of 139 185 patient admissions were included, with 541 150 antibiotics DDDs prescribed: 4637 DDDs of group 2 carbapenems and 2130 DDDs of ertapenem. A total of 779 IMP-R PA were isolated (5.6 cases/1000 admissions). Univariate analysis found a higher incidence of IMP-R PA with group 2 carbapenems (P carbapenem use was highly associated with IMP-R PA, with a 20% increase in incidence (P = 0.0014) for each 100 DDDs. Group 2 carbapenem use tended to be associated with an increased proportion of IMP-R PA (P = 0.0625) in multivariate analysis. Ertapenem was not associated with IMP-R PA. These data would support preferentially prescribing ertapenem rather than group 2 carbapenems where clinically appropriate.

  7. Views on clinically suspect arthralgia: a focus group study.

    Science.gov (United States)

    Newsum, Elize C; van der Helm-van Mil, Annette H M; Kaptein, Adrian A

    2016-05-01

    The rheumatology field is moving towards identifying individuals with an increased risk for rheumatoid arthritis (RA) at a stage when arthritis is still absent but persons having clinically suspect arthralgia (CSA). Incorporating patients' views in rheumatologic care is pivotal; however, the views of persons with CSA on their condition are unknown. We aimed to help fill this gap by exploring illness perceptions of persons with CSA and their views on hypothetical prognoses for developing RA. Persons with CSA were invited to participate in a semi-structured focus group discussion. Illness perceptions according to the Common Sense Model (CSM) and four a priori formulated themes were explored in detail during the group discussion. The discussion was audio-taped and transcribed verbatim. Transcripts were analysed in an interpretative phenomenological approach manner, on the basis of the dimensions of the CSM by three researchers independently. The views of four participants with CSA were explored during one focus group discussion. Four dimensions of the CSM were mainly observed: Identity, Consequences, Personal Control and Concern. None of the patients identified themselves as being a patient. They did experience pain and impairments in daily functioning and were concerned that their symptoms would progress. In the absence of physician-initiated treatment, some patients changed lifestyle in order to reduce pain and to promote health. Patients unanimously said that they could not interpret prognostic information on RA development expressed in hypothetical chances. Persons with CSA do not consider themselves patients. Prognostic information related to the development of RA based on risk percentages was considered as not useful by persons with CSA. Understanding of the illness perceptions of persons with CSA by health care professionals might improve medical management and facilitate shared decision-making.

  8. Functional renormalization group studies of nuclear and neutron matter

    CERN Document Server

    Drews, Matthias

    2016-01-01

    Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The questio...

  9. A renormalization in group study of supersymmetric field theories

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, Marianne

    2015-05-13

    This thesis analyses scalar supersymmetric field theories within the framework of the functional renormalization group (FRG). Classical physics on microscopic scales is connected to the effective model on macroscopic scales via the scale-dependent effective average action by a reformulation of the path integral. Three supersymmetric theories are explored in detail: supersymmetric quantum mechanics, the three-dimensional Wess-Zumino model and supersymmetric spherical theories in three dimensions. The corresponding renormalization group flow is formulated in a manifestly supersymmetric way. By utilizing an expansion of the effective average action in derivative operators, an adequate and intrinsically non-perturbative truncation scheme is selected. In quantum mechanics, the supersymmetric derivative expansion is shown to converge by increasing the order of truncation. Besides, high-accuracy results for the ground and first excited state energies for quantum systems with conserved as well as spontaneously broken supersymmetry are achieved. Furthermore, the critical behaviour of the three-dimensional Wess-Zumino is investigated. Via spectral methods, a global Wilson-Fisher scaling solution and its corresponding universal exponents are determined. Besides, a superscaling relation of the leading exponents is verified for arbitrary dimensions greater than or equal to two. Lastly, three-dimensional spherical, supersymmetric theories are analysed. Their phase structure is determined in detail for infinite as well as finitely many superfields. The exact one-parameter scaling solution for infinitely many fields is shown to collapse to a single non-trivial Wilson-Fisher fixed-point for finitely many superfields. It is pointed out that the strongly-coupled domains of these theories are plagued by Landau poles and non-analyticities, indicating spontaneous supersymmetry breaking.

  10. A well-defined rhenium(VII) olefin metathesis catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Toreki, R.; Schrock, R.R. (Massachusetts Institute of Technology, Cambridge (USA))

    1990-03-14

    Molybdenum tungsten, and rhenium are the three most active metals in classical olefin metathesis systems. Molybdenum (VI){sup 2} and tungsten(VI){sup 3} alkylidene complexes of the type M-(CHR{prime})(NAr)(OR){sub 2} (Ar = 2,6-C{sub 6}H{sub 3}-i-Pr{sub 2}) have been shown to be well-behaved olefin metathesis catalysts with an activity that can be controlled through the choice of OR. Although several rhenium alkylidene complexes have been reported, none has shown any confirmable metathesis activity, even toward strained cyclic olefins such as norbornene. Since Re{triple bond}CR{double prime} and M{double bond}NR{double prime} (M = Mo or W) can be regarded as isoelectronic units, plausible candidates as olefin metathesis catalysts are complexes of the type Re(CHR{prime})(CR{double prime})(OR){sub 2}. The authors report here that such a complex in which OR = OCMe(CF{sub 3}){sub 2} is a well-behaved olefin metathesis catalyst.

  11. Well-Defined Microapertures for Ion Channel Biosensors

    NARCIS (Netherlands)

    Halza, Erik; Bro, Tobias Hedegaard; Bilenberg, Brian; Kocer, Armagan

    2013-01-01

    Gated ion channels are excitable nanopores in biological membranes. They sense and respond to different triggers in nature. The sensory characteristics of these channels can be modified by protein engineering tools and the channels can be functionally reconstituted into synthetic lipid bilayer

  12. Ichthyosis prematurity syndrome: a well-defined congenital ichthyosis subtype

    DEFF Research Database (Denmark)

    Bygum, Anette; Westermark, Per; Brandrup, Flemming

    2008-01-01

    . The parents recalled that his elder sister had similar but milder skin changes and respiratory distress syndrome at birth. Ichthyosis prematurity syndrome was suggested and the diagnosis supported by electron microscopy of a skin biopsy specimen showing pathognomonic trilamellar membrane aggregations...... birth he developed respiratory distress and needed intubation. Remarkable skin changes were noticed with universal red, edematous and desquamating, spongy skin giving an impression of excessive vernix caseosa. Marked regression of the edema and ichthyotic scaling was observed within a few weeks......Ichthyosis prematurity syndrome is a rare syndrome characterized by the clinical triad of premature birth, thick caseous desquamating epidermis, and neonatal asphyxia. We describe two siblings with ichthyosis prematurity syndrome. The index patient was born at gestational week 34. Immediately after...

  13. In-Depth Cultural Studies in Multicultural Group

    Science.gov (United States)

    Silina-Jasjukevica, Gunta; Briška, Ilze

    2016-01-01

    There is much research and educational practices at all levels of education on how to deal with promoting acceptance and understanding between different cultures. A cultural study forms an important part of shaping intercultural understanding. "The aim" of the research is to analyze an innovative way of incorporating cultural studies in…

  14. Report of the Study Group on Yale College, 1972.

    Science.gov (United States)

    Yale Univ., New Haven, CT.

    The Study Committee on Yale College was established to study all aspects of the college and to make recommendations for the next 20 years of operation. Recommendations include the areas of faculty role, student admissions, student role, the setting of undergraduate life, the appropriate range and limits of choice in learning, the process of…

  15. NASBE Study Group Surveys State Leadership Development Policy

    Science.gov (United States)

    Newman, Bobbi; Hull, Robert

    2015-01-01

    State board members, working in partnership with the Consortium for Policy Research in Education (CPRE) at the University of Pennsylvania, conducted an in-depth study of states' school leadership development policies and practices. Data from this study are being analyzed to determine ways that states can create systems and structures for…

  16. Medical Student Perspectives of Active Learning: A Focus Group Study.

    Science.gov (United States)

    Walling, Anne; Istas, Kathryn; Bonaminio, Giulia A; Paolo, Anthony M; Fontes, Joseph D; Davis, Nancy; Berardo, Benito A

    2017-01-01

    Phenomenon: Medical student perspectives were sought about active learning, including concerns, challenges, perceived advantages and disadvantages, and appropriate role in the educational process. Focus groups were conducted with students from all years and campuses of a large U.S. state medical school. Students had considerable experience with active learning prior to medical school and conveyed accurate understanding of the concept and its major strategies. They appreciated the potential of active learning to deepen and broaden learning and its value for long-term professional development but had significant concerns about the efficiency of the process, the clarity of expectations provided, and the importance of receiving preparatory materials. Most significantly, active learning experiences were perceived as disconnected from grading and even as impeding preparation for school and national examinations. Insights: Medical students understand the concepts of active learning and have considerable experience in several formats prior to medical school. They are generally supportive of active learning concepts but frustrated by perceived inefficiencies and lack of contribution to the urgencies of achieving optimal grades and passing United States Medical Licensing Examinations, especially Step 1.

  17. Functional renormalization group studies of nuclear and neutron matter

    Science.gov (United States)

    Drews, Matthias; Weise, Wolfram

    2017-03-01

    Functional renormalization group (FRG) methods applied to calculations of isospin-symmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The question of chiral symmetry restoration in nuclear and neutron matter is addressed. A stabilization of the phase with spontaneously broken chiral symmetry is found to persist up to high baryon densities once fluctuations beyond mean-field are included. Neutron star matter including beta equilibrium is discussed under the aspect of the constraints imposed by the existence of two-solar-mass neutron stars.

  18. DFT study of glycosyl group reactivity in quercetin derivatives

    Science.gov (United States)

    Jeevitha, D.; Sadasivam, K.; Praveena, R.; Jayaprakasam, R.

    2016-09-01

    Density functional theory (DFT) is used to compute relevant electronic properties with the purpose of generating precise information which facilitates the best activity given by the positions of glycosyl group attached at all 3 different rings of quercetin such as Q3G (C- ring), Q7G (A-ring) and Q3‧G (B-ring). Computed values of the OH BDE, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), Density of states (DOS,PDOS,OPDOS) and electronic properties such as electron affinity (EA), ionization potential (IP), softness (S), hardness (η), electronegativity (χ) and electrophilic index (ω) indicate that the title compounds possess good radical scavenging activity. Charge delocalization and intramolecular hydrogen bonds are characterized using natural bond orbital (NBO) analysis. NBO accurately differentiate the weak and strong intramolecular hydrogen bond of quercetin-O-glycoside compounds. Results available from the computational investigation have proved that A-ring glycoside of quercetin is capable of donating electrons and acts as a good anti-oxidant than B-ring glycoside and C-ring glycoside of quercetin.

  19. In-depth Cultural Studies in Multicultural Group

    Directory of Open Access Journals (Sweden)

    Siliņa-Jasjukeviča Gunta

    2016-12-01

    Full Text Available There is much research and educational practices at all levels of education on how to deal with promoting acceptance and understanding between different cultures. A cultural study forms an important part of shaping intercultural understanding. The aim of the research is to analyze an innovative way of incorporating cultural studies in teacher education program from the perspective of encouraging multinational students to reveal common values within diverse manifestations of different cultures. The present article describes a qualitative study of multinational students’ experiences in international project related to the learning about Nordic and Baltic cultural traditions. In the conclusion of the article, the efficiency of the structure of content and the process of in-depth cultural studies are analyzed. The discussion contains problems for further research of this topic.

  20. Consumers' preferences for fresh yam: a focus group study.

    Science.gov (United States)

    Barlagne, Carla; Cornet, Denis; Blazy, Jean-Marc; Diman, Jean-Louis; Ozier-Lafontaine, Harry

    2017-01-01

    In West and Central Africa and in the Caribbean, yam is one of the most important sources of carbohydrates and has a great potential to improve food security. The yam production sector is, however, now challenged by the satisfaction of evolving consumers' preferences. Since little is known about consumers' preferences regarding yams' characteristics, product quality, and the drivers of yam purchase, six focus group discussions were conducted (for a total of 31 participants). Among the purchasing criteria, price was considered more important than the others. It was followed by the external damage, the origin, and the size of the tuber. The most frequently cited consumption criteria were the taste, the texture, and color of flesh after cooking. Taste was considered more important than the other criteria. Three consumers' profiles were established reflecting heterogeneity in preferences, especially as concerns the willingness to pay for yam and consumption habits. They were designated as the Hedonistic, the Thrifty and the Flexible. Our results suggest that innovations can be implemented to sustain and stimulate the development of the yam sector in Guadeloupe. Two main development paths were identified. The first path is the valorization of the great existing diversity of yam varieties and the increase in the level of information for consumers about product attributes such as the cooking mode, the origin, and the mode of production. Building a marketing strategy based on the valorization of this diversity can help maintain and preserve yam's agro-biodiversity and the satisfaction of rapidly evolving consumption habits. The second path is the definition of yam ideotypes that suit consumers' needs. We expect that tailoring the production to consumers' needs will have a positive impact on global food security in the Caribbean region.

  1. Plantar pitted keratolysis: a study from non-risk groups

    Directory of Open Access Journals (Sweden)

    Asli Feride Kaptanoglu

    2012-02-01

    Full Text Available Pitted keratolysis is an acquired, superficial bacterial infection of the skin which is characterized by typical malodor and pits in the hyperkeratotic areas of the soles. It is more common in barefooted people in tropical areas, or those who have to wear occlusive shoes, such as soldiers, sailors and athletes. In this study, we evaluated 41 patients who had been diagnosed with plantar pitted keratolysis. The patients were of high socioeconomic status, were office-workers, and most had a university degree. Malodor and plantar hyperhydrosis were the most frequently reported symptoms. The weight-bearing metatarsal parts of the feet were those most affected. Almost half the women in the study gave a history of regular pedicure and foot care in a spa salon. Mean treatment duration was 19 days. All patients were informed about the etiology of the disease, predisposing factors and preventive methods. Recurrences were observed in only 17% of patients during the one year follow-up period. This study emphasizes that even malodorous feet among non-risk city dwellers may be a sign of plantar pitted keratolysis. A study of the real incidence of the disease in a large population-based series is needed.

  2. Peer Group Status of Gender Dysphoric Children : A Sociometric Study

    NARCIS (Netherlands)

    Wallien, Madeleine S. C.; Veenstra, Rene; Kreukels, Baudewijntje P. C.; Cohen-Kettenis, Peggy T.

    2010-01-01

    In this sociometric study, we aimed to investigate the social position of gender-referred children in a naturalistic environment. We used a peer nomination technique to examine their social position in the class and we specifically examined bullying and victimization of gender dysphoric children. A

  3. Researchers' Construction of Knowledge from Studying Professional Conversation Groups

    Science.gov (United States)

    Orland-Barak, Lily; Tillema, Harm

    2007-01-01

    Data from written correspondence and conversations gathered from the authors' study on knowledge construction was used to examine the process of interpretation, or how researchers construct 'knowledge about knowledge construction.' The notion of 'working in the interpretive zone' was used to conceptualize interpretation among researchers as a…

  4. Report of the APS Neutrino Study Reactor Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Abouzaid, E.; Anderson, K.; Barenboim, G.; Berger, B.; Blucher, E.; Bolton, T.; Choubey, S.; Conrad, J.; Formaggio, J.; Freedman, S.; Finely, D.; Fisher, P.; Fujikawa, B.; Gai, M.; Goodman, M.; de Goueva, A.; Hadley, N.; Hahn, R.; Horton-Smith, G.; Kadel, R.; Kayser, B.; Heeger, K.; Klein, J.; Learned, J.; Lindner, M.; Link, J.; Luk, K.-B.; McKeown, R.; Mocioiu, I.; Mohapatra, R.; Naples, D.; Peng, J.; Petcov, S.; Pilcher, J.; Rapidis, P.; Reyna, D.; Shaevitz, M.; Shrock, R.; Stanton, N.; Stefanski, R.; Yamamoto, R.; Worcester, M.

    2004-10-28

    The worldwide program to understand neutrino oscillations and determine the neutrino mixing parameters, CP violating effects, and mass hierarchy will require a broad combination of measurements. The group believes that a key element of this future neutrino program is a multi-detector neutrino experiment (with baselines of {approx} 200 m and {approx} 1.5 km) with a sensitivity of sin{sup 2} 2{theta}{sub 13} = 0.01. In addition to oscillation physics, the reactor experiment may provide interesting measurements of sin{sup 2} {theta}{sub W} at Q{sup 2} = 0, neutrino couplings, magnetic moments, and mixing with sterile neutrino states. {theta}{sub 13} is one of the twenty-six parameters of the standard model, the best model of electroweak interactions for energies below 100 GeV and, as such, is worthy of a precision measurement independent of other considerations. A reactor experiment of the proposed sensitivity will allow a measurement of {theta}{sub 13} with no ambiguities and significantly better precision than any other proposed experiment, or will set limits indicating the scale of future experiments required to make progress. Figure 1 shows a comparison of the sensitivity of reactor experiments of different scales with accelerator experiments for setting limits on sin{sup 2} 2{theta}{sub 13} if the mixing angle is very small, or for making a measurement of sin{sup 2} 2{theta}{sub 13} if the angle is observable. A reactor experiment with a 1% precision may also resolve the degeneracy in the {theta}{sub 23} parameter when combined with long-baseline accelerator experiments. In combination with long-baseline measurements, a reactor experiment may give early indications of CP violation and the mass hierarchy. The combination of the T2K and Nova long-baseline experiments will be able to make significant measurements of these effects if sin{sup 2} 2{theta}{sub 13} > 0.05 and with enhanced beam rates can improve their reach to the sin{sup 2} 2{theta}{sub 13} > 0.02 level

  5. Down's syndrome: a ten-year group study.

    Science.gov (United States)

    Gaynon, M W; Schimek, R A

    1977-12-01

    Thirty individuals with the clinical diagnosis of Down's syndrome received ophthalmologic examination periodically over 10 years at a state school for exceptional children. External examination, retinoscopy, anterior segment evaluation, ophthalmoscopy, and tonometry were usually done. The ages at present range from 10 to 50 years. The sex ratio was 80% male and 20% female. Three subjects died during the course of the study. The most frequent ocular anomalies were oblique fissures, refractive error, blepharoconjunctivitis, epicanthus, and Brushfield's spots. All of these occurred in 50% or more of the subjects.

  6. A STUDY OF POSTOPERATIVE LARYNGOSPASM IN PAEDIATRIC AGE GROUP

    Directory of Open Access Journals (Sweden)

    Ravi Nagaprasad

    2016-04-01

    Full Text Available BACKGROUND Postoperative laryngospasm is an anaesthetic emergency that is still responsible for significant morbidity and mortality in paediatric patients. It is relatively a frequent complication and requires prompt recognition and early correction by resorting to different manoeuvres and medications. METHODS A study had been done to know the incidence of postoperative laryngospasm in our institute in the year 2014. The reported cases of laryngospasm were managed by a protocol set in algorithm and the efficacy of each step in the management algorithm was evaluated. RESULTS The incidence of Postoperative Laryngospasm in our study was found to be 9.32/1000, which was similar to that published in the literature. We also found that majority of laryngospasms can be managed by simple manoeuvres like Chin lift, Jaw thrust, Intermittent Positive Pressure Ventilation {IPPV} or Continuous Positive Airway Pressure {CPAP} with 100% O2. An Intravenous bolus dose of Propofol was found to be effective in the treatment of postoperative laryngospasm. CONCLUSION Laryngospasm even though an alarming postoperative complication can be managed effectively by simple manoeuvres and some pharmacological intervention if it is tackled by a set protocol based algorithm.

  7. Study of sunspot group morphological variations leading to flaring events

    CERN Document Server

    Korsos, M B; Ludmany, A

    2014-01-01

    It is widely assumed that the most probable sites of flare occurrences are the locations of high horizontal magnetic field gradients in the active regions. Instead of magnetograms the present work checks this assumption by using sunspot data, the targeted phenomenon is the pre-flare behaviour of the strong horizontal gradients of the magnetic field at the location of the flare. The empirical basis of the work is the SDD (SOHO/MDI-Debrecen sunspot Data) sunspot catalogue. Case studies of two active regions and five X-flares have been carried out to find possible candidates for pre-flare signatures. It has been found that the following properties of the temporal variations of horizontal magnetic field gradient are promising for flare forecast: the speed of its growth, its maximal value, its decrease after the maximum until the flare and the rate of its fluctuation.

  8. [Study of heavy-flavored particles]. [Albany High Energy Group

    Energy Technology Data Exchange (ETDEWEB)

    1993-01-01

    The program of physics analysis using CLEO II data is reported. A statistically significant measurement was made of the isospin mass splitting of the [Sigma][sub c][sup +] with respect to the [Sigma][sub c][sup o] and [Sigma][sub c][sup ++]. This result is based on first observation of the [Sigma][sub c][sup +] in the decay mode [Lambda][sub c][sup +][pi][sup 0]. Many new decay modes of the charmed baryon [Lambda][sub c][sup +] were studied. Several new decay modes of [xi][sub c]'s. Some preliminary results on 3 new modes of [Omega][sub c][sup 0] decay are reported. In the area of B-meson decay into baryons, were observed conclusively the decays B [yields] [Sigma][sub c][sup 0] and [Sigma][sub c][sup ++]. From about 1500 events corresponding to B [yields] [Lambda][sub c][sup +]X reconstruction of exclusive final states of the form [Lambda][sub c][sup +](n[pi]) was started. A comprehensive investigation of particle identification using both the time-of-flight and dE/dx systems was made. Measurement of pion, kaon and proton identification efficiencies have been made, corresponding to several different selection criteria. Measurements of corresponding pion probabilities to fake kaons nd protons have also been made.

  9. Attitudes of older adults in a group-based exercise program towards a blended intervention; a focus-group study.

    Directory of Open Access Journals (Sweden)

    Sumit Mehra

    2016-11-01

    Full Text Available Ageing is associated with a decline in daily functioning and mobility. A physically active life and physical exercise can minimize the decline of daily functioning and improve the physical-, psychological- and social functioning of older adults. Despite several advantages of group-based exercise programs, older adults participating in such interventions often do not meet the frequency, intensity or duration of exercises needed to gain health benefits. An exercise program that combines the advantages of group-based exercises led by an instructor with tailored home-based exercises can increase the effectiveness. Technology can assist in delivering a personalized program. The aim of the study was to determine the susceptibility of older adults currently participating in a nationwide group-based exercise program to such a blended exercise program. Eight focus-groups were held with adults of 55 years of age or older. Two researchers coded independently the remarks of the 30 participants that were included in the analysis according to the three key concepts of the Self Determination Theory: autonomy, competence and relatedness. The results show that maintaining self-reliance and keeping in touch with others were the main motives to participate in the weekly group-based exercises. Participants recognized benefits of doing additional home-based exercises, but had concerns regarding guidance, safety and motivation. Furthermore, some participants strongly rejected the idea to use technology to support them in doing exercises at home, but the majority was open to it. Insights are discussed how these findings can help design novel interventions that can increase the wellbeing of older adults and preserve an independent living.

  10. "It's not like a fat camp" - A focus group study of adolescents' experiences on group-based obesity treatment.

    Science.gov (United States)

    Engström, Anna; Abildsnes, Eirik; Mildestvedt, Thomas

    2016-01-01

    The health burden related to obesity is rising among children and adolescents along with the general population worldwide. For the individual as well as the society this trend is alarming. Several factors are driving the trend, and the solution seems to be multifaceted because long-lasting treatment alternatives are lacking. This study aims to explore adolescents' and young adults' motivation for attending group-based obesity treatment and social and environmental factors that can facilitate or hinder lifestyle change. In this study, we arranged three focus groups with 17 participants from different obesity treatment programs in the west and south of Norway. The content in these programs differed, but they all used Motivational Interviewing as a teaching method. We conducted a data-driven analysis using systematic text condensation. Self-determination theory has been used as an explanatory framework. We identified four major themes: 1) motivation, 2) body experience and self-image, 3) relationships and sense of belonging, and 4) the road ahead. Many of the participants expressed external motivation to participate but experienced increasing inner motivation and enjoyment during the treatment. Several participants reported negative experiences related to being obese and appreciated group affiliation and sharing experiences with other participants. Motivation may shift during a lifestyle course. Facilitating factors include achieving and experiencing positive outcomes as well as gaining autonomy support from other course participants and friends. Obstacles to change were a widespread obesogenic environment as well as feelings of guilt, little trust in personal achievements and non-supporting friends.

  11. Mentoring First Year Study Groups--Benefits from the Mentors' Perspective

    Science.gov (United States)

    Dyrberg, Nadia Rahbek; Michelsen, Claus

    2017-01-01

    The "study group concept" at the University of Southern Denmark (SDU) was implemented to aid first year students' transitional challenges. A mentor (an older student) is affiliated each study group to facilitate productive group work, bring awareness to study habits, and share his/her own experiences with life as a student. The study…

  12. Content-Related Interactions and Methods of Reasoning within Self-Initiated Organic Chemistry Study Groups

    Science.gov (United States)

    Christian, Karen Jeanne

    2011-01-01

    Students often use study groups to prepare for class or exams; yet to date, we know very little about how these groups actually function. This study looked at the ways in which undergraduate organic chemistry students prepared for exams through self-initiated study groups. We sought to characterize the methods of social regulation, levels of…

  13. Psychophysiological Measures of Learning Comfort: Study Groups' Learning Styles and Pulse Changes

    Science.gov (United States)

    Holliday, Tacy L.; Said, Sukhaynah H.

    2008-01-01

    This study provided empirical support for tutor-led study groups using a physiological measurement and study survey data. The scope of this preliminary study included determining differences in biology and chemistry study group members' (N = 25) regarding learning styles and pulse rate changes. As hypothesized, there was significant evidence that…

  14. Distribution of ABO and Rh Blood Groups in Patients With Keratoconus: A Case-Control Study.

    Science.gov (United States)

    Naderan, Mohammad; Rajabi, Mohammad Taher; Shoar, Saeed; Kamaleddin, Mohammad Amin; Naderan, Morteza; Rezagholizadeh, Farzaneh; Zolfaghari, Masoome; Pahlevani, Rozhin

    2015-07-01

    Association of keratoconus (KC) with genetic predisposition and environmental factors has been well documented. However, no single study has investigated the possible relationship between ABO and Rh blood groups and KC. A case-control study was designed in a university hospital enrolling 214 patients with KC in the case group and equal number of age- and sex-matched healthy subjects in the control group. Primary characteristics, ABO blood group, and Rh factors were compared between the two groups. Topographic findings of KC eyes and the severity of the diseases were investigated according to the distribution of the blood groups. Blood group O and Rh(+) phenotype were most frequent in both groups. There was no significant difference between the two groups in terms of ABO blood groups or Rh factors. Mean keratometery (K), central corneal thickness, thinnest corneal thickness, flat K, steep K, sphere and cylinder, spherical equivalent, and uncorrected visual acuity were all similar between ABO blood groups and Rh(+) and Rh(-) groups. However, the best spectacle-corrected visual acuity (BCVA) had the highest value in AB blood group (0.35 ± 0.22 logMAR, P=0.005). Moreover, the blood group AB revealed the highest frequency for grade 3 KC, followed by grades 1, 2, and 4 (P=0.003). We observed no significant excess of any particular blood group among KC cases compared with healthy subjects. Except BCVA, none of the keratometric or topographic findings was significantly different between blood groups.

  15. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1994 Annual Meeting (Regina, Saskatchewan, Canada, June 3-7, 1994).

    Science.gov (United States)

    Quigley, Martyn, Ed.

    These proceedings contain papers from the 1994 annual meeting of the Canadian Mathematics Education Study Group. Papers are divided into the following sections: (1) invited lectures; (2) working groups; (3) topic groups; (4) ad hoc groups; and (5) reports on ICMI (International Committee on Mathematical Instruction) studies. Papers include: (1)…

  16. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1993 Annual Meeting (York, Ontario, Canada, May 28-June 1, 1993).

    Science.gov (United States)

    Quigley, Martyn, Ed.

    These proceedings contain papers presented at the 1993 annual meeting of the Canadian Mathematics Education Study Group. Papers are presented in four sections: (1) invited lectures; (2) working groups; (3) topic groups; and (4) ad hoc groups. Papers include: (1) "What is a Square Root? A Study of Geometrical Representation in Different…

  17. A focus group study on primary health care in Johannesburg Health ...

    African Journals Online (AJOL)

    A focus group study on primary health care in Johannesburg Health District: ... Setting and subjects: Groups of nurse clinicians, clinic managers, senior ... Outcome measures: The content was thematically analysed and a model developed.

  18. A Brief Cognitive Behavioural Therapy Psychoeducational Group for Chinese People with Chronic Illnesses: An Evaluation Study

    Science.gov (United States)

    Wong, Daniel F. K.; Ip, Priscilla S. Y.; Lee, Kim Man

    2017-01-01

    This pilot study attempted to examine the effectiveness of a brief cognitive behavioural therapy (CBT) psychoeducational group for Chinese people with chronic illness in Hong Kong. It adopted a single group design, and 52 participants joined the group. A questionnaire with three outcome measures, measuring general mental health, quality of life…

  19. Effects of Group Therapy on Female Adolescent Survivors of Sexual Abuse: A Pilot Study.

    Science.gov (United States)

    Thun, Debra; Sims, Patricia L.; Adams, Mary Ann; Webb, Thomas

    2002-01-01

    Explores treatment interventions for female sexual abuse survivors through a pilot study examining the relationship between group treatment and adolescent self-image. Results revealed that participants who received group therapy increased in levels of impulse control and that the experimental group had a decrease in self-reliance whereas the…

  20. Effects of Group Therapy on Female Adolescent Survivors of Sexual Abuse: A Pilot Study.

    Science.gov (United States)

    Thun, Debra; Sims, Patricia L.; Adams, Mary Ann; Webb, Thomas

    2002-01-01

    Explores treatment interventions for female sexual abuse survivors through a pilot study examining the relationship between group treatment and adolescent self-image. Results revealed that participants who received group therapy increased in levels of impulse control and that the experimental group had a decrease in self-reliance whereas the…

  1. Can DSS Technology Improve Group Decision Performance for End Users?: An Experimental Study.

    Science.gov (United States)

    Gundersen, David E.; And Others

    1995-01-01

    Examines the benefits of Decision Support Systems (DSS) for end-user group decision making. An experiment was conducted which required groups to reach a consensus on human resource-related decisions. The results of the experiment provide implications for the use of group DDS in organizations and for future study. (Author/AEF)

  2. Group unconscious common orientation: exploratory study at the Basque Foundation for the investigation of mental health group training for therapists

    CERN Document Server

    Trojaola Zapirain, Begona; Carminati, Federico; Gonzalez Torres, Miguel Angel; Gonzalez de Mendivil, Ernesto; Fouassier, Claire; Gex-Fabry, Marianne; Martin, Francois; Labarere, Jose; Demongeot, Jacques; Lorincz, Erika Nora

    2014-01-01

    Group phenomena have been used since antiquity in therapeutic, social, economic and political domains. According to Bion, the interactions between group members generate a ``group unconscious'' and its behavior is governed and oriented by Bion's ``basic assumptions.'' The present work has been conducted during group analysis training at the Basque Foundation for the Investigation of Mental Health (OMIE) at Bilbao, consisting of eleven sessions. The participants are presented with an ``absurd questionnaire'' proposing 50 pairs of images, in each of which one image has to be chosen. The results are used to search for evidence in favor of the influence of group dynamics on individual choices of the images proposed in the questionnaire. Our analysis finds some evidence for an effect of group dynamics both on the initial choice of the pictures and on the evolution of the number of changes (swaps) of picture choices across the eleven sessions. We interpret these effects in the light of Bion's view of group dynamics...

  3. The Roles of a University Professor in a Teacher Study Group

    Science.gov (United States)

    Yeh, Hui-Chin; Hung, Hsiu-Ting; Chen, Yi-Ping

    2012-01-01

    The opportunities in which university professors collaborate with the practicing school teachers in a teacher study group are few. This study investigated how a university professor facilitated a collaborative teacher study group to enhance teachers' professional growth. Five primary school teachers and a university professor collaborated on…

  4. The Roles of a University Professor in a Teacher Study Group

    Science.gov (United States)

    Yeh, Hui-Chin; Hung, Hsiu-Ting; Chen, Yi-Ping

    2012-01-01

    The opportunities in which university professors collaborate with the practicing school teachers in a teacher study group are few. This study investigated how a university professor facilitated a collaborative teacher study group to enhance teachers' professional growth. Five primary school teachers and a university professor collaborated on…

  5. Adaptation and Flexibility When Conducting and Planning Peer Study Group Review Sessions

    Science.gov (United States)

    Arendale, David R.; Hanes, Amanda R.

    2016-01-01

    Based on an evaluation of the professional literature of postsecondary learning assistance, little is known about decisions made by student leaders during their peer study group review sessions. Our research question for this study is "How did study group leaders adapt their role to better meet the needs of the students who participated in…

  6. Study of the outcome of suicide attempts: characteristics of hospitalization in a psychiatric ward group, critical care center group, and non-hospitalized group

    Directory of Open Access Journals (Sweden)

    Kemuyama Nobuo

    2010-01-01

    Full Text Available Abstract Background The allocation of outcome of suicide attempters is extremely important in emergency situations. Following categorization of suicidal attempters who visited the emergency room by outcome, we aimed to identify the characteristics and potential needs of each group. Methods The outcomes of 1348 individuals who attempted suicide and visited the critical care center or the psychiatry emergency department of the hospital were categorized into 3 groups, "hospitalization in the critical care center (HICCC", "hospitalization in the psychiatry ward (HIPW", or "non-hospitalization (NH", and the physical, mental, and social characteristics of these groups were compared. In addition, multiple logistic analysis was used to extract factors related to outcome. Results The male-to-female ratio was 1:2. The hospitalized groups, particularly the HICCC group, were found to have biopsychosocially serious findings with regard to disturbance of consciousness (JCS, general health performance (GAS, psychiatric symptoms (BPRS, and life events (LCU, while most subjects in the NH group were women who tended to repeat suicide-related behaviors induced by relatively light stress. The HIPW group had the highest number of cases, and their symptoms were psychologically serious but physically mild. On multiple logistic analysis, outcome was found to be closely correlated with physical severity, risk factor of suicide, assessment of emergent medical intervention, and overall care. Conclusion There are different potential needs for each group. The HICCC group needs psychiatrists on a full-time basis and also social workers and clinical psychotherapists to immediately initiate comprehensive care by a medical team composed of multiple professionals. The HIPW group needs psychological education to prevent repetition of suicide attempts, and high-quality physical treatment and management skill of the staff in the psychiatric ward. The NH group subjects need a

  7. Relationship between Ecological Species Groups and Environmental Factors (Case Study: Vezg Region in Southeast of Yasouj

    Directory of Open Access Journals (Sweden)

    R. Aghaei

    2013-03-01

    Full Text Available In applied studies, identification and study of vegetation, for management and protection of natural ecosystems, are very important. This study was carried out in Vezg forest with an area of 308 hectares located in southeast of Yasouj city. The purpose of this study was to classify ecological species groups and survey their relation to soil physic-chemical properties and physiographic attributes. For this purpose, the field data were obtained using 52 sample plots (15m×30m in a systematic random grid. In each sample plot, the cover percentage of tree, shrub and grass species type were recorded, by using Braun-Blanquet method. The TWINSPAN method and Canonical Correspondence Analysis (CCA were used for the definition of ecological species groups and determintion of the relationship between ecological species groups and environmental properties. Results showed that, there were four ecological species groups in the study area. The First group included: Anchusa italic-Quercus brantii, the second group: Heteranthelium piliferum-Avena clauda, the third group: Teucrium polium and the fourth group: Salvia reautreana. The first group was in an area, where there was a higher percentage of Persian oak litter. The second group was located in site a with higher grass cover than the site of other groups in the area. The third and fourth groups, were located in the higher elevation and steep points. Results of CCA showed that soil properties were not in significant relation with ecological species groups. But, the relationships of ecological species groups with other environmental factors such as litter, altitude, grass cover and slope were significant. So, we can conclude that these properties are effective in the separation and distribution of ecological groups.

  8. A comparative study between met & unmet need groups of contraception in rural area of Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Harsha M Solanki

    2013-03-01

    Full Text Available Objectives To compare met & unmet need groups of contraception with socio-economic, demographic, accessibility & family Planning (FP related factors. Methods Community based cross-sectional, comparative study was conducted among 363 married women of reproductive age groups in rural area selected by stratified simple random technique. After collecting preliminary information, the study population then divided into two groups based on their contraceptive use i.e. MET Group & UNMET NEED Groups. Then the role of socio-economic, demographic, accessibility & family Planning (FP related factors were studies to determine contraceptive use between these groups. Results Mean age of study subjects was 24.12 ± 4.45 years & average number of children per women was 2.02. Males were more literate than females (69.1% Vs 47.2%. 51.8% women were belonging to lower socio-economic status. Early marriages were still prevalent in this study (53.7%. Prevalence of met group of contraception was 59.2% & that of unmet need for contraception was 44.1%. Met groups were mainly from 20-29 years age group (46.6%; most of them (46.8% were literate & were from high socio-economic group (30.9% compared to unmet need groups. On comparison to unmet groups, most of the met group (33.9% got married after 18 years of age, residing within 5km area (26.4%, had visited to FP centre (49.0% & ever visited by FP staff (43.3%. Conclusion Education, income, marriage age, accessibility, FP staff related factors definitely has role among met & unmet need groups in their contraceptive use.

  9. Empirical study of the influence of social groups in evacuation scenarios

    CERN Document Server

    von Krüchten, Cornelia; Svachiy, Anton; Wohak, Oliver; Schadschneider, Andreas

    2016-01-01

    The effects of social groups on pedestrian dynamics, especially in evacuation scenarios, have attracted some interest recently. However, due to the lack of reliable empirical data, most of the studies focussed on modelling aspects. It was shown that social groups can have a considerable effect, e.g. on evacuation times. In order to test the model predictions we have performed laboratory experiments of evacuations with different types and sizes of the social groups. The experiments have been performed with pupils of different ages. Parameters that have been considered are (1) group size, (2) strength of intra-group interactions, and (3) composition of the groups (young adults, children, and mixtures). For all the experiments high-quality trajectories for all participants have been obtained using the PeTrack software. This allows for a detailed analysis of the group effects. One surprising observation is a decrease of the evacuation time with increasing group size.

  10. A Case Study: An Analysis of Organizational Changes of YTO Group Corporation%A Case Study:An Analysis of Organizational Changes of YTO Group Corporation

    Institute of Scientific and Technical Information of China (English)

    Bing WANG

    2016-01-01

    This paper describes change events as a case study in a company called YTO (Luoyang)Group Corporation, and analyzes the change events utilizing constructs of organizational environments, structure, leadership and culture, in order to get a better understanding of the change in an organization.

  11. A Content Literacy Collaborative Study Group: High School Teachers Take Charge of Their Professional Learning

    Science.gov (United States)

    Thibodeau, Gail M.

    2008-01-01

    The progress and effects of a collaborative study group as a method of job-embedded professional development were studied. Eight high school teachers representing a variety of disciplines and the author (a literacy specialist) met monthly as a collaborative group for one school year to investigate materials and methods for literacy strategy…

  12. Learning to Love Reading: A Self-Study on Fostering Students' Reading Motivation in Small Groups

    Science.gov (United States)

    Miller, Rosa

    2015-01-01

    This study explores the relationship between small, differentiated reading groups and fourth-grade students' reading motivation. Using self-study methodology, the author examined her own process of implementing these reading groups through two cycles of action research. Data were analyzed from two different administrations of the Motivations for…

  13. Group Work and the Learning of Critical Thinking in the Hong Kong Secondary Liberal Studies Curriculum

    Science.gov (United States)

    Fung, Dennis; Howe, Christine

    2014-01-01

    This article reports the findings of a one-year longitudinal study that investigated the impact of group work on the development of students' critical thinking in Hong Kong secondary schools. It explores whether the participation of teachers in a group-based teaching intervention adapted from an earlier study conducted in the United Kingdom…

  14. Group Work and the Learning of Critical Thinking in the Hong Kong Secondary Liberal Studies Curriculum

    Science.gov (United States)

    Fung, Dennis; Howe, Christine

    2014-01-01

    This article reports the findings of a one-year longitudinal study that investigated the impact of group work on the development of students' critical thinking in Hong Kong secondary schools. It explores whether the participation of teachers in a group-based teaching intervention adapted from an earlier study conducted in the United Kingdom (UK)…

  15. The Principal's Role in Fostering Collaborative Learning Communities through Faculty Study Group Development

    Science.gov (United States)

    Mullen, Carol A.; Hutinger, Janice L.

    2008-01-01

    This article explores the leadership of school principals with respect to faculty study group development as a key element of the professional learning community. Questions asked concern the approaches that principals use to facilitate study group processes that, in turn. foster teacher learning and student achievement, and ways in which…

  16. [Myelogenous leukemia in children. ANLL9205 study by Children's Cancer and Leukemia Study Group (CCLSG)].

    Science.gov (United States)

    Mimaya, J; Horikoshi, Y; Shimizu, H; Maeda, H; Koizumi, S; Kawakami, K; Watanabe, A; Utsumi, J; Kikuta, A; Oka, T; Mugishima, H; Kawamura, N; Gushiken, T; Ohta, S; Yamamura, Y; Ishida, Y; Sekine, I; Okada, N; Fujimoto, T

    1997-02-01

    Treatment results were evaluated in 45 children with acute myeloblastic leukemia (AML) treated on the ANLL-9205 protocol of the Children's Cancer Leukemia Study Group (CCLSG, Japan). In this protocol, terarubicin (THP-ADR), vincristine and continuous infusion of cytosine arabinoside (Ara C) were applied for remission induction therapy (AVC), and VP16+ high dose Ara C were used sequentially for 32 or 48 weeks. Eleven patients received stem cell transplantation. Thirty-eight out of the 43 eligible patients (88.4%) achieved complete remission, and the overall 3-year event-free survival (EFS) was 55.6% (S.E.,10%). This favorable response was attributed mainly to the high induction rate of patients with the M5, M7 FAB subtypes and higher WBC counts (> or = 10 x 10(9)/L). There was no difference in the 3-year EFS of these patients who discontinued treatment between 32 weeks and 48 weeks. Serious toxicities were not observed in this study. These findings suggest that the ANLL-9205 protocol is an effective and safe treatment regimen for childhood AML. When comparing the treatment period of 32 or 48 weeks, the difference was not statistically significant.

  17. An Epidemiological Profile Of Diabetes Mellitus Amongst High Risk Age Group - A Community Based Study

    OpenAIRE

    Nadeem Ahmad; Suresh Chandra; R P Sharma; J P Srivastava; S C Saxena

    2004-01-01

    Research Question : What is the epidemiological profile of Diabetes mellitus amongst high-risk age group population in urban and rural areas of Kanpur.Objectives : To study the prevalence, magnitude, possible associates and socio demographic variables related to Diabetes mellitus amongst the high risk age group population in urban and rural areas of Kanpur.Study Design : Cross-sectional study.Setting : The study was performed on five thousand population each in urban and rural areas of Kanpur...

  18. ABO blood groups and oral premalignancies: A clinical study in selected Indian population

    Directory of Open Access Journals (Sweden)

    S Bhateja

    2014-01-01

    Full Text Available Background: The ABO blood group antigens are present on the surface of red blood cells and various epithelial cells. As the majority of human cancers are derived from epithelial cells, changes in blood group antigens constitute an important aspect of human cancers. The aim of the study was to establish clinical usefulness of ABO blood group as a predisposing factor in early diagnosis and management of patients with oral precancerous lesions/conditions. Materials and Methods: The study sample consisted of 50 control and 50 oral precancer (25 leukoplakia and 25 Oral Submucous Fibrosis confirmed by histopathologic examination. All samples were subjected to blood group testing and their prevalence was compared by Z-test using STATA version 8. Results: The "A" blood group was prevalent among the precancerous group. Significant differences on prevalences of blood groups were found (P < 0.05 between control versus leukoplakia and OSMF. Interestingly, 24% gutka chewers who had higher number of grades of dysplasia were falling in "A" blood group. Conclusion: Blood group type should be considered along with other risk factors to understand the individual patient′s risk and further studies in larger samples with inclusion of Rh factor is needed to elucidate the relationship with ABO blood group types.

  19. ABO blood groups and oral premalignancies: A clinical study in selected Indian population.

    Science.gov (United States)

    Bhateja, S; Arora, G

    2014-01-01

    Background: The ABO blood group antigens are present on the surface of red blood cells and various epithelial cells. As the majority of human cancers are derived from epithelial cells, changes in blood group antigens constitute an important aspect of human cancers. The aim of the study was to establish clinical usefulness of ABO blood group as a predisposing factor in early diagnosis and management of patients with oral precancerous lesions/conditions. Materials and Methods: The study sample consisted of 50 control and 50 oral precancer (25 leukoplakia and 25 Oral Submucous Fibrosis) confirmed by histopathologic examination. All samples were subjected to blood group testing and their prevalence was compared by Z-test using STATA version 8. Results: The "A" blood group was prevalent among the precancerous group. Significant differences on prevalences of blood groups were found (P blood group. Conclusion: Blood group type should be considered along with other risk factors to understand the individual patient's risk and further studies in larger samples with inclusion of Rh factor is needed to elucidate the relationship with ABO blood group types.

  20. Bias from historical control groups used in orthodontic research: a meta-epidemiological study.

    Science.gov (United States)

    Papageorgiou, Spyridon N; Koretsi, Vasiliki; Jäger, Andreas

    2017-02-01

    The validity of meta-analysis is dependent upon the quality of included studies. Here, we investigated whether the design of untreated control groups (i.e. source and timing of data collection) influences the results of clinical trials in orthodontic research. This meta-epidemiological study used unrestricted literature searching for meta-analyses in orthodontics including clinical trials with untreated control groups. Differences in standardized mean differences (ΔSMD) and their 95% confidence intervals (CIs) were calculated according to the untreated control group through multivariable random-effects meta-regression controlling for nature of the interventional group and study sample size. Effects were pooled with random-effects synthesis, followed by mixed-effect subgroup and sensitivity analyses. Studies with historical control groups reported deflated treatment effects compared to studies with concurrent control groups (13 meta-analyses; ΔSMD = -0.31; 95% CI = -0.53, -0.10; P = 0.004). Significant differences were found according to the type of historical control group (based either on growth study or clinical archive; 11 meta-analyses; ΔSMD = 0.40; 95% CI = 0.21, 0.59; P control groups in orthodontic clinical research was associated with deflation of treatment effects, which was independent from whether the interventional group was prospective or retrospective and from the study's sample size. Caution is warranted when interpreting clinical studies with historical untreated control groups or when interpreting systematic reviews that include such studies. PROSPERO (CRD42015024179). None. © The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Individual and group antecedents of job satisfaction: a one-lab multilevel study

    Directory of Open Access Journals (Sweden)

    Isabel M. Martínez

    Full Text Available This study examines the simultaneous effect of individual (selfefficacy and group variables (cohesion and gender diversity on satisfaction. A laboratory study was conducted involving 373 college students randomly distributed across 79 small groups, who performed a laboratory task in about five hours. Two-level Hierarchical Linear Modeling (HLM method was used. Results show the main effect from individual selfefficacy to satisfaction (both level 1, the cross-level effect from group cohesion (level 2 to individual satisfaction (level 1, and the interaction effect between self-efficacy and gender diversity to satisfaction. These results suggest that in a work group, satisfaction has a background in individual and group variables. Group cohesion and gender diversity have important effects on satisfaction. The article concludes with practical strategies and with limitations and suggestions for future research.

  2. Containing psychotic patients with fragile boundaries: a single-session group case study.

    Science.gov (United States)

    Lavarenne, Anaïs; Segal, Emily; Sigman, Maxine

    2013-01-01

    This case study describes a single group psychotherapy session of six individuals suffering from schizophrenia or schizoaffective illness, which was characterized by numerous manifestations of fragile Ego boundaries. Based on these illustrations of fragile Ego boundaries, we explore some of the group's core therapeutic actions against psychosis. We discuss how the group (1) provides access to a structuring auxiliary Ego, (2) acts as a containing object by establishing firm boundaries and by mentalizing patients' psychotic productions, and (3) may become a solid object representation introjected by individuals wrestling with porous Ego boundaries and a poor sense of self. We conclude that, in addition to the known role of group therapy in increasing mature defenses, developing insight and providing social support, the group promotes healthier Ego boundaries, and eventually improves self-differentiation, and also tolerance to interpersonal proximity. This case study clarifies group therapy dynamics with individuals suffering from psychosis.

  3. ABO blood group system and gastric cancer: a case-control study and meta-analysis.

    Science.gov (United States)

    Wang, Zhiwei; Liu, Lei; Ji, Jun; Zhang, Jianian; Yan, Min; Zhang, Jun; Liu, Bingya; Zhu, Zhenggang; Yu, Yingyan

    2012-10-17

    This study focuses on the association between the ABO blood group system and the risk of gastric cancer or Helicobacter pylori infection. The data for the ABO blood group was collected from 1045 cases of gastric cancer, whereby the patient underwent a gastrectomy in Ruijin Hospital, Shanghai. The information on the ABO blood group from 53,026 healthy blood donors was enrolled as control. We searched the Pubmed database on the relationship between ABO blood groups and gastric cancer risk for meta-analysis. In our case-control study, the risk of gastric cancer in blood group A was significantly higher than that in non-A groups (O, B and AB) (odd ratio, OR1.34; 95% confidential interval, CI 1.25-1.44). Compared with non-O groups (A, B and AB), individuals with blood group O demonstrated a reduced risk of gastric cancer (OR = 0.80; 95% CI 0.72-0.88). The proportion of H. pylori infection in blood group A individuals was significantly higher than that in non-A blood groups (OR = 1.42; 95% CI 1.05-1.93). We further combined our data with the published data of others, and crossreferenced the risk of gastric cancer with the blood type, finding consistent evidence that gastric cancer risk in the blood A group was higher than that in the non-A groups (OR = 1.11; 95% CI 1.07-1.15), and that blood type O individuals were consistently shown gastric cancer risk reduction (OR = 0.91; 95% CI 0.89-0.94). Our study concluded that there was a slightly increased risk of gastric cancer in blood group A individuals, and people with blood type A are more prone to be infected by H. pylori than other ABO blood type individuals, whereas, a slightly decreased risk of gastric cancer was identified in blood type O individuals.

  4. Correlates of Regular Participation in Sports Groups among Japanese Older Adults: JAGES Cross-Sectional Study.

    Directory of Open Access Journals (Sweden)

    Mitsuya Yamakita

    Full Text Available Participation in a sports group is key for the prevention of incident functional disability. Little is known about the correlates of older adults' participation in sports groups, although this could assist with the development of effective health strategies. The purpose of this study was to identify the demographic and biological, psychosocial, behavioral, social and cultural, and environmental correlates of sports group participation among Japanese older adults.Data were obtained from the Japan Gerontological Evaluation study, which was a population-based cohort of people aged ≥65 years without disability enrolled from 31 municipalities across Japan (n = 78,002. Poisson regression analysis was used to determine the associations between the factors and participation in sports groups.Non-regular participation in sports groups was associated with lower educational level, being employed, and working the longest in the agricultural/forestry/fishery industry among the demographic and biological factors and poor self-rated health and depression among the psychosocial factors. Of the behavioral factors, current smoking was negatively associated and current drinking was positively associated with regular participation in sports groups. Among the social and cultural factors, having emotional social support and participating in hobby clubs, senior citizen clubs, or volunteer groups were associated with a high prevalence of participation in sports groups. Perceptions of the presence of parks or sidewalks, good access to shops, and good accessibility to facilities were positively associated with participation in sports groups among the environmental factors.Our study suggests that the promotion of activities that could increase older adults' participation in sports groups should consider a broad range of demographic and biological, psychosocial, behavioral, social and cultural, and environmental factors. Although future longitudinal studies to elucidate

  5. Genetic predisposition to chikungunya – a blood group study in chikungunya affected families

    OpenAIRE

    Ramakrishna Vadde; Sarojamma Vemula; Sudarsanareddy Lokireddy

    2009-01-01

    Abstract Chikungunya fever is a viral disease transmitted to humans by the bite of CHIKV virus infected Aedes mosquitoes. During monsoon outbreak of chikungunya fever, we carried out the genetic predisposition to chikungunya in disease affected 100 families by doing blood group (ABO) tests by focusing on individuals who were likely to have a risk of chikungunya and identified the blood group involved in susceptibility/resistance to chikungunya. In the present study, based on blood group antig...

  6. A STUDY TO FIND CORRELATION BETWEEN DERMATOGLYPHIC PATTERNS AND ABO BLOOD GROUPS

    Directory of Open Access Journals (Sweden)

    Usha Verma

    2015-09-01

    Full Text Available Background: Dermatoglyphics, the study of fingerprints are constant and individualistic. It has been found useful in forensic medicine and identification purpose. It is useful in medical diagnosis of genetically inherited diseases and in detection of crimes. Objectives: The present study was conducted to correlate between digital dermatoglyphics patterns in ABO, Rh blood groups and to evaluate their significance. Methods: A total of 200 first year MBBS students of Pt. B.D. Sharma PGIMS, Rohtak with known blood groups from age group 17-22 yrs were included in the study. Fingerprints were obtained by Ink method. Parameters studied were arches, whorls, loops. Results: Majority of the subjects (43.5% in the study were of blood group A followed by blood group O, A and AB of whom 94.5% were Rh-positive. The general distribution of pattern of finger print showed high frequency (51.87% of loops followed by whorls and arches. Almost same order was noticed in both Rh-positive and Rh-negative individuals or A, B, AB and O blood groups, except blood group O-ve which showed more whorls. Conclusion: There is an association between distribution of finger print pattern and blood groups.

  7. Dorsomedial prefrontal cortex and cerebellar contribution to in-group attitudes: a transcranial magnetic stimulation study.

    Science.gov (United States)

    Gamond, Lucile; Ferrari, Chiara; La Rocca, Stefania; Cattaneo, Zaira

    2017-04-01

    We tend to express more positive judgments and behaviors toward individuals belonging to our own group compared to other (out-) groups. In this study, we assessed the role of the cerebellum and of the dorsomedial prefrontal cortex (dmPFC) - two regions critically implicated in social cognition processes - in mediating implicit valenced attitudes toward in-group and out-group individuals. To this aim, we used transcranial magnetic stimulation (TMS) in combination with a standard attitude priming task, in which Caucasian participants had to categorize the valence of a series of adjectives primed by either an in-group or an out-group face. In two behavioral experiments, we found an in-group bias (i.e. faster categorization of positive adjectives when preceded by in-group faces) but no evidence of an out-group bias. Interestingly, TMS over both the dmPFC and over the (right) cerebellum significantly interfered with the modulation exerted by group membership on adjective valence classification, abolishing the in-group bias observed at baseline. Overall, our data suggest that both the dmPFC and the cerebellum play a causal role in mediating implicit social attitudes.

  8. The Differences between Novice and Expert Group-Piano Teaching Strategies: A Case Study and Comparison of Beginning Group Piano Classes

    Science.gov (United States)

    Pike, Pamela D.

    2014-01-01

    This case study compares the teaching strategies employed by a novice and an expert instructor of two beginning children's group-piano classes. In the United States, there is a century-long tradition of teaching piano to children in groups, and group teaching is championed in pedagogy texts and at professional educator conferences throughout…

  9. The Differences between Novice and Expert Group-Piano Teaching Strategies: A Case Study and Comparison of Beginning Group Piano Classes

    Science.gov (United States)

    Pike, Pamela D.

    2014-01-01

    This case study compares the teaching strategies employed by a novice and an expert instructor of two beginning children's group-piano classes. In the United States, there is a century-long tradition of teaching piano to children in groups, and group teaching is championed in pedagogy texts and at professional educator conferences throughout…

  10. Resource Allocation in Divisionalized Groups : A Study of Investment Manuals and Corporate Means of Control

    OpenAIRE

    Segelod, Esbjörn

    1995-01-01

    How do corporate management in divisionalized groups control the direction of investments? There are many case-studies and postal surveys of capital budgeting procedures. This study represents a different approach, being founded on analyses of investment manuals and interviews with corporate managers of Swedish-based groups. Comparisons are made with UK and US studies throughout the book. The book shows how investment requests are handled and the means of control which corporate managers deem...

  11. Using Web-Based, Group Communication Systems to Support Case Study Learning at a Distance

    Directory of Open Access Journals (Sweden)

    Liam Rourke

    2002-10-01

    Full Text Available This study explored the capacity of Web-based, group communication systems to support case-based teaching and learning. Eleven graduate students studying at a distance were divided into three groups to collaborate on a case study using either a synchronous voice, an asynchronous voice, or a synchronous text communication system. Participants kept a detailed log of the time they spent on various activities, wrote a 1,500-word reflection on their experience, and participated in a group interview. Analysis of these data reveals that each group supplemented the system that had been assigned to them with additional communication systems in order to complete the project. Each of these systems were used strategically: email was used to share files and arrange meetings, and synchronous voice systems were used to brainstorm and make decisions. Learning achievement was high across groups and students enjoyed collaborating with others on a concrete task.

  12. Study on the Superluminal Group Velocity in a Coaxial Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    LuGuizhen; HuangZhixun; GuanJian

    2004-01-01

    In this paper, the superluminal group velocity in a coaxial photonic crystal is studied. The simulation of the effective refraction index in coaxial photonic crystal is performed. The group velocity is calculated based on the transmission line equations and compared with experimental results.

  13. Measurement Error Correction Formula for Cluster-Level Group Differences in Cluster Randomized and Observational Studies

    Science.gov (United States)

    Cho, Sun-Joo; Preacher, Kristopher J.

    2016-01-01

    Multilevel modeling (MLM) is frequently used to detect cluster-level group differences in cluster randomized trial and observational studies. Group differences on the outcomes (posttest scores) are detected by controlling for the covariate (pretest scores) as a proxy variable for unobserved factors that predict future attributes. The pretest and…

  14. Nurture Groups: A Large-Scale, Controlled Study of Effects on Development and Academic Attainment

    Science.gov (United States)

    Reynolds, Sue; MacKay, Tommy; Kearney, Maura

    2009-01-01

    Nurture groups have contributed to inclusive practices in primary schools in the UK for some time now and have frequently been the subject of articles in this journal. This large-scale, controlled study of nurture groups across 32 schools in the City of Glasgow provides further evidence for their effectiveness in addressing the emotional…

  15. School Finance and Technology: A Case Study Using Grid and Group Theory to Explore the Connections

    Science.gov (United States)

    Case, Stephoni; Harris, Edward L.

    2014-01-01

    Using grid and group theory (Douglas 1982, 2011), the study described in this article examined the intersections of technology and school finance in four schools located in districts differing in size, wealth, and commitment to technology integration. In grid and group theory, grid refers to the degree to which policies and role prescriptions…

  16. Organometallic nucleoside analogues with ferrocenyl linker groups: synthesis and cancer cell line studies.

    Science.gov (United States)

    Nguyen, Huy V; Sallustrau, Antoine; Balzarini, Jan; Bedford, Matthew R; Eden, John C; Georgousi, Niki; Hodges, Nikolas J; Kedge, Jonathan; Mehellou, Youcef; Tselepis, Chris; Tucker, James H R

    2014-07-10

    Examples of organometallic compounds as nucleoside analogues are rare within the field of medicinal bioorganometallic chemistry. We report on the synthesis and properties of two chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group. These so-called ferronucleosides show promising anticancer activity, with cytostatic studies on five different cancer cell lines indicating that both functional groups are required for optimal activity.

  17. Summary Report of the Defense Science Study Group, 1985-1988

    Science.gov (United States)

    1989-09-01

    8217 -,’Copy 24 of 150 Copies NIDA PAPER P-2310 Two I SUMMARY REPORT OF THE 0 DEFENSE SCIENCE STUDY GROUP 1985 - 1988 0 DTIC JAN 3 11990 Richard J...CARRUTHERS Head, Department of Physics University of Arizona * RUTH DAVIS** President The Pymatuning Group, Inc. ALEXANDER H. FLAX Private Consultant EUGENE

  18. Exploratory Study of MOOC Learners' Demographics and Motivation: The Case of Students Involved in Groups

    Science.gov (United States)

    Bayeck, Rebecca Yvonne

    2016-01-01

    This paper reports preliminary findings on students enrolled in a massive open online course, who were also assigned to work in groups. Part of a larger study on the effect of groups on retention and completion in MOOCs, the paper provides students' demographics (i.e., location, gender, education level, and employment status), and motivation for…

  19. Group physical therapy during inpatient rehabilitation for acute spinal cord injury: findings from the SCIRehab Study.

    Science.gov (United States)

    Zanca, Jeanne M; Natale, Audrey; Labarbera, Jacqueline; Schroeder, Sally Taylor; Gassaway, Julie; Backus, Deborah

    2011-12-01

    Inpatient rehabilitation for spinal cord injury (SCI) includes the use of both individual and group physical therapy sessions. A greater understanding of group physical therapy use will help in the evaluation of the appropriateness of its use and contribute to the development of standards of practice. This report describes the extent to which group physical therapy is being used in inpatient rehabilitation for SCI, identifies group physical therapy interventions being delivered, and examines patterns in the types of activities being used for people with different levels and completeness of injury (ie, injury groups). The SCIRehab Study is a 5-year, multicenter investigation that uses practice-based evidence research methodology. Data on characteristics of participants and treatments provided were collected through detailed chart review and customized research documentation completed by clinicians at the point of care. The analyses described here included data from 600 participants enrolled during the first year of the project. Most of the participants (549/600) spent time in group physical therapy, and 23% of all documented physical therapy time was spent in group sessions. The most common group physical therapy activities were strengthening, manual wheelchair mobility, gait training, endurance activities, and range of motion/stretching. Time spent in group physical therapy and the nature of activities performed varied among the injury groups. Physical therapy use patterns observed in the 6 participating centers may not represent all facilities providing inpatient rehabilitation for SCI. Research documentation did not include all factors that may affect group physical therapy use, and some sessions were not documented. The majority of physical therapy was provided in individual sessions, but group physical therapy contributed significantly to total physical therapy time. Group physical therapy time and activities differed among the injury groups in patterns

  20. Surface properties of a single perfluoroalkyl group on water surfaces studied by surface potential measurements.

    Science.gov (United States)

    Shimoaka, Takafumi; Tanaka, Yuki; Shioya, Nobutaka; Morita, Kohei; Sonoyama, Masashi; Amii, Hideki; Takagi, Toshiyuki; Kanamori, Toshiyuki; Hasegawa, Takeshi

    2016-12-01

    A discriminative study of a single perfluoroalkyl (Rf) group from a bulk material is recently recognized to be necessary toward the total understanding of Rf compounds based on a primary chemical structure. The single molecule and the bulk matter have an interrelationship via an intrinsic two-dimensional (2D) aggregation property of an Rf group, which is theorized by the stratified dipole-arrays (SDA) theory. Since an Rf group has dipole moments along many C-F bonds, a single Rf group would possess a hydrophilic-like character on the surface. To reveal the hydration character of a single Rf group, in the present study, surface potential (ΔV) measurements are performed for Langmuir monolayers of Rf-containing compounds. From a comparative study with a monolayer of a normal hydrocarbon compound, the hydration/dehydration dynamics of a lying Rf group on water has first been monitored by ΔV measurements, through which a single Rf group has been revealed to have a unique "dipole-interactive" character, which enables the Rf group interacted with the water 'surface.' In addition, the SDA theory proves to be useful to predict the 2D aggregation property across the phase transition temperature of 19°C by use of the ΔV measurements.

  1. The use of group participation and an enquiry-based study guide with computer assisted learning.

    Science.gov (United States)

    Botelho, M

    2001-08-01

    The aim of this investigation was to explore the use of group participation and an enquiry-based study guide to enhance the learning experience when using a computer assisted learning (CAL) program. Forty-eight students were asked to complete a CAL program on resin bonded bridges in groups of 2-4 with an enquiry-based study guide. An evaluation questionnaire of the learning experience was included with the study guide with paired positive and negative questions and open-ended questions for students to complete and return. The responses were collated and the nature of the comments qualitatively analysed. Thirty-two questionnaires were returned. There were almost three times the numbers of positive to negative responses relating to the usefulness of the enquiry based study guide, group participation and the CAL program. The majority of these positive responses related to the usefulness of the study guide and group participation in highlighting and guiding learning and creating opportunities for discussion, problem solving and peer teaching. A small number of negative responses cited the target-orientated nature of the study guide and the longer time needed for group work, due to the varying learning abilities of the participants and the need for discussion. The use of group participation and an enquiry-based study guide was reported to enhance the learning experience of CAL.

  2. Parental illness perceptions and medication perceptions in childhood asthma, a focus group study

    NARCIS (Netherlands)

    Klok, Ted; Brand, Paul L.; Bomhof-Roordink, Hanna; Duiverman, Eric J.; Kaptein, Adrian A.

    Aim: Asthma treatment according to guidelines fails frequently, through patients' nonadherence to doctors' advice. This study aimed to explore how differences in asthma care influence parents' perceptions to inhaled corticosteroids (ICS). Methods: We conducted six semistructured focus groups,

  3. [The course of varicose disease. Parallel retrospective study of 2 ethnic groups (Catania-Basel)].

    Science.gov (United States)

    Rosato, E; Zemp, E; Chiarenza, S; Biland, L; Grasso, A; Landmann, J; Romeo, S; Widmer, L K

    1989-01-01

    Authors presents a retrospective study with two different ethnic groups, one of them from Catania and the other from Basilea, with varicose veins and subjected to a saphenectomy. They studies the following parameters: age at the entrance, and when varicose veins appeared; correlation between varix appearance date and subjective symptomatology; and rapport between varix complications and its duration. The possible incidence of "ambiental factor" and contrasts between the two groups are considered.

  4. Formation of the U.S. Air Force Aviator Post Traumatic Stress Disorder Study Group

    Science.gov (United States)

    2016-11-15

    ABSTRACT The first aviator mental health study groups (post-traumatic stress disorder (PTSD) and antidepressants) were approved by the Chief of Aerospace...mental health study groups (post-traumatic stress disorder (PTSD) and antidepressants) were approved by the Chief of Aerospace Medicine for the...traffic controllers were now required to meet enhanced medical standards similar to traditional aircrew such as pilots, navigators, and loadmasters. In

  5. Experiences of older adults in a group physiotherapy program at a rehabilitation hospital: A qualitative study.

    Science.gov (United States)

    Raymond, Melissa J; Burge, Angela T; Soh, Sze-Ee; Jeffs, Kimberley J; Winter, Adele; Holland, Anne E

    2016-05-01

    Physiotherapy delivered in a group setting has been shown to be effective in a variety of populations. However, little is known about the attitudes of older adults toward participating in group physiotherapy. The objectives of this study were to explore older inpatients' perceptions and experiences of group physiotherapy using qualitative methods. Twelve hospitalized adults aged ≥65 years who were involved in a larger randomized controlled trial undertook individual semistructured interviews regarding their experiences in group physiotherapy. Interviews were transcribed verbatim, and line by line, iterative thematic analysis was undertaken. Descriptive codes were developed, compared, and grouped together to create themes. Analysis revealed 6 major themes and 10 subthemes. All participants reported feeling happy to attend group sessions, a satisfactory alternative to individual physiotherapy. Participants described physical benefits that increased their motivation, and comparisons with their peers either motivated them or made them feel gratitude for their own health. Perceived attentiveness of group instructors contributed to participants reporting that treatment was individualized and similar to individual physiotherapy. Motivation and camaraderie with peers contributed to their enjoyment of group physiotherapy. Hospitalized older adults enjoyed exercising with their peers and valued the physical and social benefits of group physiotherapy. Journal of Hospital Medicine 2016;11:358-362. © 2016 Society of Hospital Medicine. © 2016 Society of Hospital Medicine.

  6. Improving the Reading Ability of Science Students through Study Groups and Multiple Intelligences

    Science.gov (United States)

    Owolabi, Tunde; Okebukola, Foluso

    2009-01-01

    This study explored the effects of appropriate pedagogical skills (study groups and multiple intelligences) on students' efficiencies in reading skills. It employed a factorial design using three variables. A sample of 90 science students choosing from three intact classes were involved in the study. Data analyses were carried out using mean,…

  7. The Effectiveness of Lecture-Integrated, Web-Supported Case Studies in Large Group Teaching

    Science.gov (United States)

    Azzawi, May; Dawson, Maureen M.

    2007-01-01

    The effectiveness of lecture-integrated and web-supported case studies in supporting a large and academically diverse group of undergraduate students was evaluated in the present study. Case studies and resource (web)-based learning were incorporated as two complementary interactive learning strategies into the traditional curriculum. A truncated…

  8. Recommendations by Cochrane Review Groups for assessment of the risk of bias in studies

    Directory of Open Access Journals (Sweden)

    Gøtzsche Peter C

    2008-04-01

    Full Text Available Abstract Background Assessing the risk of bias in individual studies in a systematic review can be done using individual components or by summarizing the study quality in an overall score. Methods We examined the instructions to authors of the 50 Cochrane Review Groups that focus on clinical interventions for recommendations on methodological quality assessment of studies. Results Forty-one of the review groups (82% recommended quality assessment using components and nine using a scale. All groups recommending components recommended to assess concealment of allocation, compared to only two of the groups recommending scales (P Conclusion We found that recommendations by some groups were not based on empirical evidence and many groups had no recommendations on how to use the quality assessment in reviews. We suggest that all Cochrane Review Groups refer to the Cochrane Handbook for Systematic Reviews of Interventions, which is evidence-based, in their instructions to authors and that their own guidelines are kept to a minimum and describe only how methodological topics that are specific to their fields should be handled.

  9. Data-driven intensity normalization of PET group comparison studies is superior to global mean normalization

    DEFF Research Database (Denmark)

    Borghammer, Per; Aanerud, Joel; Gjedde, Albert

    2009-01-01

    BACKGROUND: Global mean (GM) normalization is one of the most commonly used methods of normalization in PET and SPECT group comparison studies of neurodegenerative disorders. It requires that no between-group GM difference is present, which may be strongly violated in neurodegenerative disorders....... Importantly, such GM differences often elude detection due to the large intrinsic variance in absolute values of cerebral blood flow or glucose consumption. Alternative methods of normalization are needed for this type of data. MATERIALS AND METHODS: Two types of simulation were performed using CBF images...... from 49 controls. Two homogeneous groups of 20 subjects were sampled repeatedly. In one group, cortical CBF was artificially decreased moderately (simulation I) or slightly (simulation II). The other group served as controls. Ratio normalization was performed using five reference regions: (1) Global...

  10. Effect of Acetyl Group on Mechanical Properties of Chitin/Chitosan Nanocrystal: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Junhe Cui

    2016-01-01

    Full Text Available Chitin fiber is the load-bearing component in natural chitin-based materials. In these materials, chitin is always partially deacetylated to different levels, leading to diverse material properties. In order to understand how the acetyl group enhances the fracture resistance capability of chitin fiber, we constructed atomistic models of chitin with varied acetylation degree and analyzed the hydrogen bonding pattern, fracture, and stress-strain behavior of these models. We notice that the acetyl group can contribute to the formation of hydrogen bonds that can stabilize the crystalline structure. In addition, it is found that the specimen with a higher acetylation degree presents a greater resistance against fracture. This study describes the role of the functional group, acetyl groups, in crystalline chitin. Such information could provide preliminary understanding of nanomaterials when similar functional groups are encountered.

  11. Case Studies in Exploiting Terrorist Group Divisions with Disinformation and Divisive/Black Propaganda

    Directory of Open Access Journals (Sweden)

    George Garner

    2010-07-01

    Full Text Available Counterterrorism operations should be exploiting the divisions and infighting of terrorist groups.  The overall goal should be to make fewer mistakes than the jihadis, help increase inter-group and intra-group tension, and further their disconnection from the wider public. This paper argues that strategic psychological operations (PSYOP that focus on exploiting rifts in leadership, differences in strategic planning, and ethnic, national and tribal differences within and among terrorist groups could be an integral part of overall counterterrorism efforts. Using three case studies, chosen because of the attention given to them in the international community and the illuminating group and leadership characteristics that can be found in many other jihadist organisations, the paper illustrates that PSYOP that expand on the existing framework could be very effective in countering the jihadist threat.

  12. Studies on the Development of Interest Group Populations in Corporative Systems

    DEFF Research Database (Denmark)

    Fisker, Helene Marie

    This dissertation investigates how the Danish population of interest groups develops over time and whether population mechanisms, societal factors, and corporative institutions can explain this development. How interest group populations develop and which factors explain this development...... are important questions with implications for the quality of democracy. The answers can indicate the degree of bias and diversity in interest group populations. Earlier studies have especially focused on snapshots of the composition of interest group populations and not on the dynamics and development...... of populations. The dissertation attempts to fill this gap in the literature by investigating the development of a total interest group population. The central claim of the dissertation is that societal factors and population dynamics can explain how a population develops and that corporative institutions...

  13. PENGARUH GROUP INVESTIGATION BERBASIS OUTDOOR STUDY TERHADAP KEMAMPUAN BERPIKIR ANALITIS SISWA

    Directory of Open Access Journals (Sweden)

    Valeriana Rasweda

    2016-02-01

    Full Text Available The purpose of research is to find out the Group Investigation outdoor study-based having an affect on student’s analytichal thinking ability. The type of research is PretestPosttest Control Group Design. The research was conducted at Lawang 1st Public Senior High School Malang Regency with experiment class X-IIS 1 and control class X-IIS 2. The data is an analytichal thinking ability. Data analysis was done by comparing the gain score student’s analytichal thinking ability using SPSS 17.0 for Windows. The results showed that Group Investigation outdoor study-based having an affect on student’s analytichal thinking ability.  Tujuan penelitian ini adalah untuk mengetahui apakah model Group Investigation berbasis outdoor study berpengaruh terhadap kemampuan berpikir analitis siswa. Penelitian ini merupakan jenis penelitian eksperimen semu (quasi experiment yang termasuk penelitian kuantitatif. Rancangan penelitian yang dikembangkan adalah Pretest-Posttest Control Group Design. Penelitian dilaksanakan di SMA Negeri 1 Lawang Kabupaten Malang. Kelas ekperimen ialah kelas X-IIS 1 dan kelas kontrol ialah kelas X-IIS 2. Data yang digunakan dalam penelitian ini adalah kemampuan berpikir analitis. Analisis data dilakukan dengan membandingkan gain score kemampuan berpikir analitis siswa menggunakan bantuan program SPSS 17.0 for Windows. Hasil dari penelitian ini menunjukkan bahwa model Group Investigation berbasis outdoor study berpengaruh terhadap kemampuan berpikir analitis siswa.

  14. A study of group reminiscence therapy and emotional intelligence among elderly members

    Directory of Open Access Journals (Sweden)

    Azam Bazooband

    2016-09-01

    Full Text Available This study aims to investigate the effects of group reminiscence therapy on elderly’s emotional intelligence. A quasi-experimental research with a pre-test-post-test control group was conducted in July 2015, with a sample of 40 elderly members referring to an (anonymous Community Center in the city of Shiraz, Iran. A predesigned instrument, i.e., the Emotional Intelligence Questionnaire developed by Schering, was applied to collect data. SPSS Statistics v. 22.0 (Released 2013; IBM Corp., Armonk, NY, USA was used to analyze data, with a 95% confidence level and a measurement error of α=0.05. Hypothesis tests were mainly conducted to examine whether group reminiscence therapy correlates with emotional intelligence among the respondents. Findings revealed that the applied intervention i.e., group reminiscence therapy significantly associates with various dimensions of emotional intelligence including self-awareness, self-control, self-motivation, empathy and social skills in the older adults within the experiment group; i.e., the mean scores of the variables for the post-test administered on the experimental group were significantly higher than those on the control group. Group reminiscence therapy has the potential to enhance emotional intelligence in the elderly by helping them control their thoughts and emotions and learn problem-solving skills.

  15. Smoking and peer groups: results from a longitudinal qualitative study of young people in Northern Ireland.

    Science.gov (United States)

    Stewart-Knox, Barbara J; Sittlington, Julie; Rugkåsa, Jorun; Harrisson, Sheila; Treacy, Margaret; Abaunza, Pilar Santos

    2005-09-01

    Previous research has indicated that young people are under considerable social pressure to take up smoking. This study has therefore sought to explore and better understand the mechanisms through which peer-related social factors operate to encourage young people to smoke. Individual qualitative interviews were held with adolescent children aged 11-12 years (N = 102) within youth clubs based in economically deprived areas of Northern Ireland, and then followed up on two occasions during the subsequent 3 years (N = 51/39). The data implied that, although peers influence smoking uptake, this seldom happens through direct persuasion, but rather as the result of the young person striving to conform to the normative behaviour of the peer group with which they identify. The findings are consistent with social identity theory and self-categorization theory in that for both smoking and nonsmoking 14-year-olds smoking activity appears to provide a means through which to define social groups, to accentuate similarity within groups and differences between groups. In-group favouritism was expressed in the sharing of cigarettes within the in-group and in the negative stereotyping of out-group members. There was some evidence that group affiliation may be negotiated differently for boys and girls. These findings imply that successful intervention needs to reconsider the normative processes that encourage young people to smoke.

  16. Study on The Development of The Group-Buying:A Secondary Business-Model Innovation Perspective

    Institute of Scientific and Technical Information of China (English)

    Xia; Yiwei

    2011-01-01

    Groupon group-buying business model promotes the development of e-commerce market in China.This group-buying model has obvious advantages.But it can be easily copied.There are thousands of group-buying websites,which are as much popular as Web 2.0and SNS entered China a few years ago.Although group-buying has been domestic only more than a year,it developed fast which has gradually changed the lifestyle of consumers and become a living habit.Therefore,it has great significance to study on the group-buying in the pattern of localization.We try to analyze the phenomena of local group-buying in Chinese market from business model innovation perspective,which has the impact on their competitive performance.We find that local group-buying sites get success through business model innovation.They clearly put forward the appropriate value proposition to attract customersattention with low-cost feature for specific target consumer groups.Moreover,they take advantage of their unique resources,integration of complementary assets to enhance the value of network systems.Thus,these latecomer e-commerce firms seize the opportunity to grow in emerging economies and have won a huge customer base.

  17. Polycystic ovary syndrome, blood group & diet: A correlative study in South Indian females

    Directory of Open Access Journals (Sweden)

    Rahul Pal, Pratik Kumar Chatterjee, Poulomi Chatterjee, Vinodini NA, PrasannaMithra, Sourjya Banerjee, Suman VB2, Sheila R. Pai

    2014-07-01

    Full Text Available Aim: To find out the co-relation between polycystic ovary syndrome (PCOS with blood group & diet in South Indian females, between the age-group of (20-30 years. Objectives: Correlative analysis of ABO & Rh system, dietary habits & alcohol consumption with PCOS. Materials & Methods: 100 patients between (20-30 years, diagnosed with PCOS were selected. A standard PCOS questionnaire was given. Blood group & dietary status data were collected. Patients were grouped according to ABO & Rh system considering their diet & alcohol intake (p≤0.05 significant. Result: Our data revealed that the highest risk of PCOS was observed in females with blood group ‘O’ positive followed by ‘B’ positive who were on mixed diet & used to consume alcohol. Our study also suggests that Rh negative individuals didn’t show any association with PCOS. Conclusion: The results of our study suggest that ‘O’ positive females, are more prone to PCOS. Though the relative frequency of B positive individuals are more in India, females with blood group O positive are more susceptible to PCOS, contributing factors being mixed diet & alcohol intake. So, early screening of ‘O’ positive &‘B’ positive females of reproductive age-group in South-India, could be used as a measure for timely diagnosis of PCOS, better management &also prevention of complications. However, further research should be done to investigate the multifaceted mechanisms triggering these effects.

  18. Group training with healthy computing practices to prevent repetitive strain injury (RSI): a preliminary study.

    Science.gov (United States)

    Peper, Erik; Gibney, Katherine H; Wilson, Vietta E

    2004-12-01

    This pilot study investigated whether group training, in which participants become role models and coaches, would reduce discomfort as compared to a nontreatment Control Group. Sixteen experimental participants participated in 6 weekly 2-hr group sessions of a Healthy Computing program whereas 12 control participants received no training. None of the participants reported symptoms to their supervisors nor were they receiving medical treatment for repetitive strain injury prior to the program. The program included training in ergonomic principles, psychophysiological awareness and control, sEMG practice at the workstation, and coaching coworkers. Using two-tailed t tests to analyze the data, the Experimental Group reported (1) a significant overall reduction in most body symptoms as compared to the Control Group and (2) a significant increase in positive work-style habits, such as taking breaks at the computer, as compared to the Control Group. This study suggests that employees could possibly improve health and work style patterns based on a holistic training program delivered in a group format followed by individual practice.

  19. Self-development groups reduce medical school stress: a controlled intervention study

    Directory of Open Access Journals (Sweden)

    Stordal Kirsten I

    2010-03-01

    Full Text Available Abstract Background High stress levels and mental health problems are common among medical students and there is a lack of studies on group interventions that aim to reduce such distress during medical school. Methods A full class of students (n = 129 participated in group sessions during their third year of medical school in Bergen, Norway. The subsequent third-year class (n = 152 acted as control group, in order to create a quasi-experimental design. Two types of group intervention sessions were offered to the first class. One option was self-development groups led by trained group psychotherapists. Alternatively, students could choose discussion groups that focused on themes of special relevance to doctors, led by experienced general practitioners. The intervention comprised of 12 weekly group sessions each lasting 90 minutes. Data were gathered before the intervention (T1, and three months post intervention (T2. Distress was measured using the Perceived Medical School Stress (PMSS and Symptom Check List-5 (SCL-5 assessments. Results The intervention group showed a significant reduction in PMSS over the observation period. The subsequent year control group stayed on the same PMSS levels over the similar period. The intervention was a significant predictor of PMSS reduction in a multiple regression analysis adjusted for age and sex, β = -1.93 (-3.47 to -0.38, P = 0.02. When we analysed the effects of self-development and discussion groups with the control group as reference, self-development group was the only significant predictor of PMSS reduction, β = -2.18 (-4.03 to -0.33, P = 0.02. There was no interaction with gender in our analysis. This implicates no significant difference between men and women concerning the effect of the self-development group. There was no reduction in general mental distress (SCL-5 over this period. Conclusion A three-month follow-up showed that the intervention had a positive effect on perceived medical school

  20. Health effects of war stress on Norwegian World War II resistance groups: a comparative study.

    Science.gov (United States)

    Major, Ellinor F

    2003-12-01

    The main aim of this study was to investigate the extent to which adverse long-term health effects of World War II stress exposure were present in 3 groups of resistance veterans. The groups had been exposed to different types of war stressors: concentration camp incarceration, resistance participation within the illegal press, and a secret military organization. With the differences in war stressors as a basis, we assumed that those incarcerated in a concentration camp would display more adverse health effect compared to the resistance veterans. The findings point to a relationship between the severity of war stressors and postwar health in all 3 groups.

  1. Improving Parental Stress Levels Among Mothers Living with HIV: A Randomized Control Group Intervention Study

    OpenAIRE

    Johnson, Erica R.; Davies, Susan L.; Aban, Inmaculada; Mugavero, Michael J.; Shrestha, Sadeep; Kempf, Mirjam-Colette

    2015-01-01

    Limited knowledge exists regarding parenting efficacy interventions for mothers living with HIV (MLH). This study evaluated the impact of a supportive group intervention on lowering parenting stress among MLH. Eighty MLH were randomized to a parenting (N=34) or health focused (control) (N=46) group intervention. Pre- and post-intervention stress levels were assessed using the Parental Stress Index-Short Form (PSI/SF). Differences in PSI/SF scores were examined using ANOVA, and predictors of P...

  2. Study on critical conditions for rock failure by means of group renormallzation

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-rui; GAO Zhao-ning; WANG Xiang-qian

    2009-01-01

    A study of the characteristics of the accumulative rock failure and its evolution by application of the group renormalization method were presented.In addition,the interaction and long-range correlated effects between the immediate neighboring units was studied.The concept of mechanical transference for model OFC,employed in the study of self-organized criticality,and the coefficient a were introduced into the calculation model for group renormalization.With the introduction,mechanisms for the drastic increase and de-crease of failure intensity of rocks were investigated under similar macro-conditions.

  3. Mortality from Diabetes by Hispanic Groups: Evidence from the US National Longitudinal Mortality Study

    Directory of Open Access Journals (Sweden)

    Augustine J. Kposowa

    2013-01-01

    Full Text Available Diabetes is a leading cause of morbidity and mortality in the United States, especially in minority communities. In mortality research, Hispanics are frequently studied as a homogeneous group. The present study was undertaken to compare diabetes deaths among persons of Hispanic origin by disaggregating groups in order to determine whether the components in the Hispanic label have differential mortality. Data utilized were from the US National Longitudinal Mortality Study. Cox proportional hazards regression models were fitted to the data. Findings showed that individuals in the broader Hispanic label were 28% more likely to die from diabetes mellitus than non-Hispanic whites (ARR = 1.28, CI = 1.05, 1.55. When groups were broken down, it was observed that Mexicans were 50% more likely to die of diabetes than their non-Hispanic white counterparts. No other Hispanic origin group was significantly associated with diabetes mortality risk. Education and family income were strong predictors of mortality, regardless of Hispanic origin grouping. It was concluded from the analysis that future behavioral and social science research would be more informative if the broader Hispanic label was broken down into subcategories. Failure to do so might lead to drawing false inferences as a finding may well hold for one group within the Hispanic label, but not for others.

  4. Parametric analyses of summative scores may lead to conflicting inferences when comparing groups: A simulation study.

    Science.gov (United States)

    Khan, Asaduzzaman; Chien, Chi-Wen; Bagraith, Karl S

    2015-04-01

    To investigate whether using a parametric statistic in comparing groups leads to different conclusions when using summative scores from rating scales compared with using their corresponding Rasch-based measures. A Monte Carlo simulation study was designed to examine between-group differences in the change scores derived from summative scores from rating scales, and those derived from their corresponding Rasch-based measures, using 1-way analysis of variance. The degree of inconsistency between the 2 scoring approaches (i.e. summative and Rasch-based) was examined, using varying sample sizes, scale difficulties and person ability conditions. This simulation study revealed scaling artefacts that could arise from using summative scores rather than Rasch-based measures for determining the changes between groups. The group differences in the change scores were statistically significant for summative scores under all test conditions and sample size scenarios. However, none of the group differences in the change scores were significant when using the corresponding Rasch-based measures. This study raises questions about the validity of the inference on group differences of summative score changes in parametric analyses. Moreover, it provides a rationale for the use of Rasch-based measures, which can allow valid parametric analyses of rating scale data.

  5. An Epidemiological Profile Of Diabetes Mellitus Amongst High Risk Age Group - A Community Based Study

    Directory of Open Access Journals (Sweden)

    Nadeem Ahmad

    2004-06-01

    Full Text Available Research Question : What is the epidemiological profile of Diabetes mellitus amongst high-risk age group population in urban and rural areas of Kanpur.Objectives : To study the prevalence, magnitude, possible associates and socio demographic variables related to Diabetes mellitus amongst the high risk age group population in urban and rural areas of Kanpur.Study Design : Cross-sectional study.Setting : The study was performed on five thousand population each in urban and rural areas of Kanpur. Participants : High risk age group population i.e. 45 years and above.Study variables: Age, sex, education, working status, social class. Impaired glucose tolerance. Body mass index, Hypertension, family history of diabetes mellitus.Statistical analysis : Chi-square test. Percentages.Results : The overall prevalence of Diabetes mellitus amongst high risk age group population was found to be 7.6% with 11.3% in urban areas and 3.6% in rural areas. The overall maximum prevalence was in the 56-60 years age group. Higher prevalence was observed amongst the graduates and onwards (30.1%, social class-1 (32.1%, sedentary lifestyle (62.5%, obese (19.7%. hypertensives (39.5%, family history of diabetes mellitus (31.5%. It was observed that 77.7% cases in rural areas and 26.9% cases in urban areas were newly diagnosed.

  6. Factors Affecting Ethnic Minority Students' Attainment in Secondary Schools in Cyprus: A Focus Group Study

    Science.gov (United States)

    Theodosiou-Zipiti, Galatia; West, Mel; Muijs, Daniel

    2010-01-01

    This is the first study in Cyprus aiming to gain insight into the factors responsible for the low attainment of ethnic minority students observed in earlier studies. Teachers from different schools and cities on the island participated in a focus group discussion. Identified factors related to the child, parents, home environment, teachers,…

  7. A Case Study: An ACT Stress Management Group in a University Counseling Center

    Science.gov (United States)

    Daltry, Rachel M.

    2015-01-01

    The aim of this study was to examine the effectiveness of an acceptance and commitment therapy (ACT) stress management group in a college counseling center setting. This study explored (a) the effectiveness of ACT in increasing participants' ability to tolerate distress, which directly affects their ability to function in a stressful college…

  8. Facilitating Group Analysis of Two Case Studies Utilising Peer Tutoring: Comparison of Tasks and Outcomes

    Science.gov (United States)

    Fong, Lin Siew

    2016-01-01

    Peer-tutoring sessions of two groups of advanced diploma in financial accounting students with mixed proficiency were analysed thoroughly in this study. Numerous studies in peer tutoring have produced favourable results to both tutors and tutees due to the scaffolding process which promotes effective learning. However, there is a lack of studies…

  9. Treatment of Depression and Anxiety in Parkinson's Disease: A Pilot Study Using Group Cognitive Behavioural Therapy

    Science.gov (United States)

    Feeney, Farah; Egan, Sarah; Gasson, Natalie

    2005-01-01

    Depression and anxiety affect up to 50% of people with Parkinson's Disease (PD) (Marsh, 2000; Murray, 1996), however, few studies have examined the effectiveness of psychological treatment. This study examined the effectiveness of group cognitive behaviour therapy (CBT) in treating depression and anxiety in PD. Four participants, aged between 56…

  10. Liberal Studies in Hong Kong: A New Perspective on Critical Thinking through Group Work

    Science.gov (United States)

    Fung, Dennis; Howe, Christine

    2012-01-01

    This article reports research that is contextualised within reforms of secondary education in Hong Kong and the reintroduction of Liberal Studies, which jointly emphasise the need for a learning environment that facilitates the practice of group work and the development of critical thinking. A study is described that explores the relevance of…

  11. Educational needs of general practitioners in palliative care : Outcome of a focus group study

    NARCIS (Netherlands)

    Meijler, WJ; Van Heest, F; Otter, R; Sleijfer, DT

    2005-01-01

    Background. The objective of this study was to identify the general practitioner's perception of educational needs in palliative care. Method. A qualitative study with focus groups was performed. Results. General practitioners estimate palliative care as an important and valuable part of primary car

  12. Participation, Interaction and Social Presence: An Exploratory Study of Collaboration in Online Peer Review Groups

    Science.gov (United States)

    Zhao, Huahui; Sullivan, Kirk P. H.; Mellenius, Ingmarie

    2014-01-01

    A key reason for using asynchronous computer conferencing in instruction is its potential for supporting collaborative learning. However, few studies have examined collaboration in computer conferencing. This study examined collaboration in six peer review groups within an asynchronous computer conferencing. Eighteen tertiary students participated…

  13. Children's Experiences and Meaning Construction on Parental Divorce: A Focus Group Study

    Science.gov (United States)

    Maes, Sofie D. J.; De Mol, Jan; Buysse, Ann

    2012-01-01

    The global aim of this study was to explore children's narratives of parental divorce. A convenience sample, composed of 11- and 14-year-old children, was recruited. A total of 22 children (12 male, 10 female) participated in this focus group study. The findings show that two components seem to be really important for children during the divorce…

  14. A Case Study of Group Processes and Student Evaluation of Teaching

    Science.gov (United States)

    Mortenson, Kristian G.; Sathe, Richard S.

    2017-01-01

    This paper documents a case study undertaken to understand the effect of group processes on student evaluation of teaching (SET). The study used interviews to investigate the experiences of students in a cohort model Master of Science in Accountancy degree program and how those experiences influenced SET. The cohort served as an extreme example in…

  15. Splenectomy in children with idiopathic thrombocytopenic purpura : A prospective study of 134 children from the Intercontinental Childhood ITP Study Group

    NARCIS (Netherlands)

    Kuehne, Thomas; Blanchette, Victor; Buchanan, George R.; Ramenghi, Ugo; Donato, Hugo; Tamminga, Rienk Y. J.; Rischewski, Johannes; Berchtold, Willi; Imbach, Paul

    2007-01-01

    Background. Splenectomy is an effective procedure for children and adults with severe or refractory idiopathic thrombocytopenic purpura (ITP). Data regarding pediatric patients are limited. Procedure. Sixty-eight Intercontinental Childhood ITP Study Group (ICIS) investigators from 57 institutions in

  16. Regular group exercise contributes to balanced health in older adults in Japan: a qualitative study.

    Science.gov (United States)

    Komatsu, Hiroko; Yagasaki, Kaori; Saito, Yoshinobu; Oguma, Yuko

    2017-08-22

    While community-wide interventions to promote physical activity have been encouraged in older adults, evidence of their effectiveness remains limited. We conducted a qualitative study among older adults participating in regular group exercise to understand their perceptions of the physical, mental, and social changes they underwent as a result of the physical activity. We conducted a qualitative study with purposeful sampling to explore the experiences of older adults who participated in regular group exercise as part of a community-wide physical activity intervention. Four focus group interviews were conducted between April and June of 2016 at community halls in Fujisawa City. The participants in the focus group interviews were 26 older adults with a mean age of 74.69 years (range: 66-86). The interviews were analysed using the constant comparative method in the grounded theory approach. We used qualitative research software NVivo10® to track the coding and manage the data. The finding 'regular group exercise contributes to balanced health in older adults' emerged as an overarching theme with seven categories (regular group exercise, functional health, active mind, enjoyment, social connectedness, mutual support, and expanding communities). Although the participants perceived that they were aging physically and cognitively, the regular group exercise helped them to improve or maintain their functional health and enjoy their lives. They felt socially connected and experienced a sense of security in the community through caring for others and supporting each other. As the older adults began to seek value beyond individuals, they gradually expanded their communities beyond geographical and generational boundaries. The participants achieved balanced health in the physical, mental, and social domains through regular group exercise as part of a community-wide physical activity intervention and contributed to expanding communities through social connectedness and

  17. Canadian Mathematics Education Study Group = Groupe Canadien d'etude en didactique des mathematiques. Proceedings of the 1995 Annual Meeting (Ontario, Canada, May 26-30, 1995).

    Science.gov (United States)

    Pothier, Yvonne M., Ed.

    These proceedings contain the papers presented at the 1995 annual meeting of the Canadian Mathematics Education Study Group. Papers are organized into four sections: (1) plenary lectures; (2) working groups; (3) topic sessions; and (4) ad hoc sessions. Papers include: (1) "The Role of Epistemology in the Analysis of Teaching/Learning…

  18. The impact of instructor grouping strategies on student efficacy in inquiry science labs: A phenomenological case study of grouping perceptions and strategies

    Science.gov (United States)

    Miller, Nathaniel J.

    Abundant educational research has integrated Albert Bandura's concepts of self-efficacy and collective efficacy within educational settings. In this phenomenological case study, the investigation sought to capture the manifestation of self-efficacy and collective efficacy within inquiry-based science laboratory courses. Qualitative data was derived from student efficacy surveys, direct classroom observations, and three-tiered interviews with teacher participants. Four high school science instructors and their students from two school districts in Northern Illinois were selected to participate in the study. This study sought to identify instructor strategies or criteria used to formulate student laboratory groups and the impact of such groupings on student self-efficacy and collective efficacy. Open coding of interview transcripts, observation logs, and student surveys led to the development of eight emerging themes. These themes included the purpose of science laboratory activities, instructor grouping strategies, instructor roles, instructor's perceptions, science laboratory assessment, student interactions, learner self-perceptions, and grouping preferences. Results from the study suggest that some students were innately inclined to assume leadership roles, smaller groupings had greater participation from all group members, students had a strong preference for working collaboratively in groups, and students desired to maintain stable laboratory groups in lieu of periodically changing laboratory partners. As with all case study methodologies, the findings of the study were limited to the individual participants at research sites and were not generalizable to all science classrooms. Additional research in the realms of group size, group autonomy, and student interviews would provide even greater insights into the observed phenomena.

  19. Experimental study on small group behavior and crowd dynamics in a tall office building evacuation

    Science.gov (United States)

    Ma, Yaping; Li, Lihua; Zhang, Hui; Chen, Tao

    2017-05-01

    It is well known that a large percentage of occupants in a building are evacuated together with their friends, families, and officemates, especially in China. Small group behaviors are therefore critical for crowd movement. This paper aims to study the crowd dynamic considering different social relations and the impacts of small groups on crowd dynamics in emergency evacuation. Three experiments are conducted in an 11-storey office building. In the first two experiments, all participants are classmates and know each other well. They are evacuated as individuals or pairs. In the third experiment, social relations among the participants are complex. Participants consist of 8 families, 6 lovers and several individuals. Space-time features, speed characteristics and density-speed relations for each experiment are analyzed and compared. Results conclude that small group behaviors can make positive impacts on crowd dynamics when evacuees know each other and are cooperative. This conclusion is also testified by four verified experiments. In the third experiment, speeds of evacuees are lowest. Small groups form automatically with the presence of intimate social relations. Small groups in this experiment slow down the average speed of the crowd and make disturbance on the crowd flow. Small groups in this case make negative impacts on the movement of the crowd. It is because that evacuees do not know each other and they are competitive to each other. Characteristics of different types of small groups are also investigated. Experimental data can provide foundational parameters for evacuation model development and are helpful for building designers.

  20. The group matters: an explorative study of group cohesion and quality of life in cancer patients participating in physical exercise intervention during treatment

    DEFF Research Database (Denmark)

    Klausen, Julie Midtgaard; Rørth, Mikael Rahbek; Stelter, Reinhard

    2006-01-01

    -C30) was assessed at baseline and after Week 6. The interviews revealed that group cohesion was an interim goal aimed to maximize peak performance potential by patients. Group cohesion was characterized by a special 'esprit de corps' and enabled the group members to feel like sport teams....... The programme made purposeful togetherness possible while allowing the patients an opportunity to let their illness fade into the background. Questionnaire data showed significant improvements in mental health, social and emotional functioning. This study identified a conceptualization of group cohesion...

  1. Systematic study of simple-leaved group of Astragalus sect. Incani DC. in Iran

    Directory of Open Access Journals (Sweden)

    Massoud Ranjbar

    2010-12-01

    Full Text Available In this investigation, morphological pollen characteristics of different populations of 5 species belonging to simple-leaved group of Astragalus sect. Incani DC. in Iran were studied. Results showed that all studied taxa formed two groups. In addition, chromosome number and meiotic behavior were studied in 3 populations belonging to two species of this group. All taxa were diploid and had the basic chromosome number of 2n = 2x = 16. Although the taxa represented regular meiosis, but some abnormalities such as laggard and fragmented chromosomes in anaphase/telophase I and II and diakinesis/methaphase I, cytomixis in anaphase/telophase I and II, multipolar cells in telophase II, binucleouli cells in prophase I and bridges in anaphase I and telophase II were obseved.

  2. ABO Blood Group and Dementia Risk--A Scandinavian Record-Linkage Study

    DEFF Research Database (Denmark)

    Vasan, Senthil K; Rostgaard, Klaus; Ullum, Henrik;

    2015-01-01

    BACKGROUND: Dementia includes a group of neuro-degenerative disorders characterized by varying degrees of cognitive impairment. Recent data indicates that blood group AB is associated with impaired cognition in elderly patients. To date there are no large-scale studies that have examined the rela......BACKGROUND: Dementia includes a group of neuro-degenerative disorders characterized by varying degrees of cognitive impairment. Recent data indicates that blood group AB is associated with impaired cognition in elderly patients. To date there are no large-scale studies that have examined...... the relationship between ABO blood group and dementia-related disorders in detail. METHODS: We used data from the SCANDAT2 database that contains information on over 1.6 million blood donors from 1968 in Sweden and 1981 from Denmark. The database was linked with health outcomes data from nationwide patient...... and cause of death registers to investigate the relationship between blood groups and risk of different types of dementia. The incident rate ratios were estimated using log-linear Poisson regression models. RESULTS: Among 1,598,294 donors followed over 24 million person-years of observation we ascertained 3...

  3. Experiences with Recruitment of Marginalized Groups in a Danish Health Promotion Program: A Document Evaluation Study

    Science.gov (United States)

    Kristiansen, Tine Mechlenborg; Bak, Carsten Kronborg

    2016-01-01

    Background Studies have found that marginalized groups living in deprived neighborhoods are less likely to participate in health programs compared to the majority of society. This study evaluates recruitment approaches conducted during a national government-funded project in 12 deprived neighborhoods across Denmark between 2010 and 2014. The aim of this study was to understand how recruitment approaches could promote participation in health programs within deprived neighborhoods to reach marginalized groups. Method Documents from all 12 of the included municipalities were collected to conduct a document evaluation. The collected documents consisted of 1,500 pages of written material with 12 project descriptions, three midterm and 10 final evaluations. The collected data were analyzed through a qualitative content analysis. Results The results are based on the fact that only 10 municipalities have developed evaluations related to recruitment, and only three evaluations provided a description of which marginalized groups were recruited. Challenges related to recruitment consist of difficulties involving the target group, including general distrust, language barriers and a lack of ability to cope with new situations and strangers. Additional geographical challenges emerged, especially in rural areas. Positive experiences with recruitment approaches were mainly related to relationship building and trust building, especially through face-to-face contact and the project employees’ presence in the neighborhood. Additionally, adjusting some of the interventions and the recruitment strategy increased participation. Conclusion This study found that relation and trust between the residents and the project employees is an important factor in the recruitment of marginalized groups in deprived neighborhoods as well as adjusting the health interventions or recruitment strategy to the target groups. In future research, it is necessary to examine which recruitment approaches are

  4. Group cohesion and social support in exercise classes: results from a danish intervention study

    DEFF Research Database (Denmark)

    Christensen, Ulla; Schmidt, Lone; Budtz-Jørgensen, Esben;

    2006-01-01

    This study examines the formation of group cohesion and social support in exercise classes among former sedentary adults, participating in a Danish community-based intervention. Furthermore, the aim is to analyze the impact of this process on exercise activity among the participants. A multimethod...... approach was used, analyzing both survey data and 18 personal interviews collected among 87 participants who completed the intervention project. Analysis was performed according to the grounded theory method. The formation of group cohesion was conditioned by the social composition of the group......, the teaching ability by the instructors, and the activity by itself. The cohesive group was characterized by an attitude of mutual support toward exercise activities. This mutual support facilitated development of self-efficacy beliefs among the participants improving their mastery expectation regarding...

  5. EFL student teachers’ learning in a peer-tutoring research study group

    Directory of Open Access Journals (Sweden)

    John Jairo Viafara

    2014-09-01

    Full Text Available In order to become peer-tutors in a B.A program in Modern Languages, a group of EFL (English as a Foreign Language student teachers attended a study and research group in a university. Throughout their participation, prospective teachers collaborated and reflected by means of tasks completion and dialogue to learn the theory and practice of tutoring and research. Additionally, participants provided survey, journal and interview data to contribute with the exploration of how their group membership shaped them academically and personally. Results suggested that student teachers increased their knowledge of English due to their use of real-life group dynamics, among others. Furthermore, they updated and expanded their competencies to monitor pedagogical situations, design strategies and solve problems.

  6. Teaching the Moon: A Study of Teaching Methodology Across Age Groups

    Science.gov (United States)

    Tucker, F.; Paust, N.

    2012-08-01

    In this study I attempted to determine the most effective teaching style for teaching elementary, middle school, and undergraduate students about lunar phases and eclipses. Within each age group, there were two sub groups, one of which was introduced to the material in a standard lecture format while the other sub-group interacted with the content through activities and demonstrations. After their respective lessons, both sub-groups were given the same post-instruction test in order to assess their comprehension of the content. The results from this experiment provided insight into effective teaching styles and common misconceptions about lunar phases and eclipses at different age levels, as well as introducing new interactive teaching activities for elementary, middle school and undergraduate students.

  7. A comparative study of prelinguistic vocalizations in two groups of cleft toddlers and a non-cleft group

    DEFF Research Database (Denmark)

    Willadsen, Elisabeth; Enemark, Hans

    2000-01-01

    closure of the lip and hard palate at 3 months of age and soft palate closure at 22 months of age. Design: Retrospective study. Setting: The participants were videorecorded in their homes during play with their mothers. The videotapes were transcribed independently by three trained speech pathologists...

  8. ABO Blood Group and Dementia Risk--A Scandinavian Record-Linkage Study.

    Directory of Open Access Journals (Sweden)

    Senthil K Vasan

    Full Text Available Dementia includes a group of neuro-degenerative disorders characterized by varying degrees of cognitive impairment. Recent data indicates that blood group AB is associated with impaired cognition in elderly patients. To date there are no large-scale studies that have examined the relationship between ABO blood group and dementia-related disorders in detail.We used data from the SCANDAT2 database that contains information on over 1.6 million blood donors from 1968 in Sweden and 1981 from Denmark. The database was linked with health outcomes data from nationwide patient and cause of death registers to investigate the relationship between blood groups and risk of different types of dementia. The incident rate ratios were estimated using log-linear Poisson regression models.Among 1,598,294 donors followed over 24 million person-years of observation we ascertained 3,615 cases of Alzheimer's disease, 1,842 cases of vascular dementia, and 9,091 cases of unspecified dementia. Overall, our study showed no association between ABO blood group and risk of Alzheimer's disease, vascular dementia or unspecified dementia. This was also true when analyses were restricted to donors aged 70 years or older except for a slight, but significantly decreased risk of all dementia combined in subjects with blood group A (IRR, 0.93; 95% confidence interval [CI], 0.88-0.98, compared to those with blood group O.Our results provide no evidence that ABO blood group influences the risk of dementia.

  9. Papers from the NSU Summer session of 2014 - study group 3

    DEFF Research Database (Denmark)

    Rendtorff, Jacob Dahl

    2014-01-01

    In this special issue we present the conference papers by the study group “Crisis and Crisis Scenarios: Normativity, Possibilities and Dilemmas” at the 2014 NSU Summer Session, held between 24th July and 31st July 2014 in Sauðárkrókur, Northern Iceland.......In this special issue we present the conference papers by the study group “Crisis and Crisis Scenarios: Normativity, Possibilities and Dilemmas” at the 2014 NSU Summer Session, held between 24th July and 31st July 2014 in Sauðárkrókur, Northern Iceland....

  10. Pattern of clustering of menopausal problems: A study with a Bengali Hindu ethnic group.

    Science.gov (United States)

    Dasgupta, Doyel; Pal, Baidyanath; Ray, Subha

    2016-01-01

    We attempted to find out how menopausal problems cluster with each other. The study was conducted among a group of women belonging to a Bengali-speaking Hindu ethnic group of West Bengal, a state located in Eastern India. We recruited 1,400 participants for the study. Information on sociodemographic aspects and menopausal problems were collected from these participants with the help of a pretested questionnaire. Results of cluster analysis showed that vasomotor, vaginal, and urinary problems cluster together, separately from physical and psychosomatic problems.

  11. Using focus groups to discover health professionals' information needs: a regional marketing study.

    Science.gov (United States)

    Mullaly-Quijas, P; Ward, D H; Woelfl, N

    1994-07-01

    This paper describes the use of focus groups as a data-gathering tool, in both theoretical and practical terms. Calder's discussion of focus groups is presented as the basis of the theory, and the marketing study conducted by the Midcontinental Region of the National Network of Libraries of Medicine serves as the backdrop to highlight some of the practical aspects of using this qualitative data-gathering method. Results of the marketing study are presented to illustrate the types of data that can be gathered using this methodology and the types of plans for future activities that can be developed based on the data gathered.

  12. Leading a study-abroad group of nursing students in Nicaragua: a first-timer's account.

    Science.gov (United States)

    Christoffersen, Jean E

    2008-01-01

    Readiness to lead a study-abroad group of nursing students in Nicaragua. Given the abundance of study-abroad programs now offered in colleges and universities, this first-hand account of a nursing faculty member's decision to bring a group of nursing students to Nicaragua may help other nursing faculty members considering taking on a similar challenge. The author shares her thoughts and worries before agreeing to lead the 2-week trip. She then describes the day-to-day experience of being in Nicaragua with her students. In the end, the rewards of the experience won over both this professor and her student nurses.

  13. When does diversity trump ability (and vice versa in group decision making? A simulation study.

    Directory of Open Access Journals (Sweden)

    Shenghua Luan

    Full Text Available It is often unclear which factor plays a more critical role in determining a group's performance: the diversity among members of the group or their individual abilities. In this study, we addressed this "diversity vs. ability" issue in a decision-making task. We conducted three simulation studies in which we manipulated agents' individual ability (or accuracy, in the context of our investigation and group diversity by varying (1 the heuristics agents used to search task-relevant information (i.e., cues; (2 the size of their groups; (3 how much they had learned about a good cue search order; and (4 the magnitude of errors in the information they searched. In each study, we found that a manipulation reducing agents' individual accuracy simultaneously increased their group's diversity, leading to a conflict between the two. These conflicts enabled us to identify certain conditions under which diversity trumps individual accuracy, and vice versa. Specifically, we found that individual accuracy is more important in task environments in which cues differ greatly in the quality of their information, and diversity matters more when such differences are relatively small. Changing the size of a group and the amount of learning by an agent had a limited impact on this general effect of task environment. Furthermore, we found that a group achieves its highest accuracy when there is an intermediate amount of errors in the cue information, regardless of the environment and the heuristic used, an effect that we believe has not been previously reported and warrants further investigation.

  14. The role of a teacher study group in negotiating constructivist science teaching in an elementary school

    Science.gov (United States)

    Schiller, Ellen Louise

    2000-12-01

    This study arose from the frustrations expressed by elementary teachers in a mid-size, urban school district who were involved in implementing a new district-wide science curriculum. The new curriculum was designed to meet the recommendations for constructivist teaching espoused in the current science education reform movement. As a fifth-grade teacher in the district as well, as a member of the science curriculum committee that wrote the new curriculum, I was in the position to hear the frustrations vented by fellow teachers as they struggled to make the shift from a loosely-supervised, textbook-based curriculum to one which emphasized hands-on instruction through four in-depth units at each grade level. In response to teachers' frustrations, I conducted an action-research study designed to provide a sustained, personalized, professional development opportunity for a group of elementary teachers in the building in which I taught. The study group of five teachers met during the course of the 1996--97 school year to work on familiarizing ourselves with the tenets of constructivist science teaching and learning and incorporating this type of teaching into our own practice. Activities engaged in included: reading relevant literature, viewing videotapes of teachers practicing constructivist science teaching, attending physics workshops, working with the intermediate school-district science consultant, and videotaping our own science lessons for the purposes of sharing with the other group members and studying our practice. During the year, I conducted individual interviews with the teacher participants and audiotaped all group meetings in an effort to learn if this experience held value as a means of helping the group members become more constructivist science teachers. During the year, it became clear that the teachers continued to face many obstacles as they worked to improve their science teaching. While the participants felt they made progress and all agreed that

  15. Yoga Plus Talk Therapy for Depression: A Case Study of a Six Week Group

    Directory of Open Access Journals (Sweden)

    Kelli Foulkrod

    2017-01-01

    Full Text Available Yoga is increasingly becoming a popular method of addressing mental health symptoms. While there is research to support the use of yoga for depression, there is limited literature examining yoga in combination with talk therapy groups as a treatment for depression. The results of this case study series (n=4 provide support for the clinical efficacy of yoga in combination with talk therapy. Treatment consisted of 6 weeks of group sessions (90-min sessions each week with weekly home practice. Each group consisted of yoga, meditation, breathwork, and emotional processing. Decreases in depressive symptoms and increases in self-compassion were found. The findings of the case study are relevant because growing numbers of clients are presenting with depression and seeking alternative treatments.

  16. Photophysical studies of oxicam group of NSAIDs: piroxicam, meloxicam and tenoxicam

    Science.gov (United States)

    Banerjee, Rona; Chakraborty, Hirak; Sarkar, Munna

    2003-04-01

    Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular group that shows diverse biological functions and dynamic structural features. Photophysical studies of three drugs from this group viz., piroxicam, meloxicam and tenoxicam have been carried out in different solvents with varying polarity, H-bond character and viscosity. The spectral responses of different prototropic forms of these drugs towards varying solvent parameters have been studied, with the aim to characterize their interaction in biomimetic environment non-invasively. The nature of the lowest transition has been identified. The extinction coefficient, quantum yield and viscosity dependence on the nature of the solvents, all indicate the extreme sensitivity of these drugs to their microenvironment.

  17. Patients' experiences and expectations of general practice: a questionnaire study of differences by ethnic group

    Science.gov (United States)

    Ogden, Jane; Jain, Asha

    2005-01-01

    Background Research has highlighted variations in morbidity, mortality and health needs by ethnic group, and suggests that some ethnic groups may receive a poorer service. Aim To explore the impact of ethnic group on patients' experiences and expectations of their general practice consultation. Design of study Cross-sectional survey. Setting One general practice in a multicultural area of London. Method A total of 604 consecutive patients attending their general practice (response rate = 60.4%) who described their ethnic group as white British, black African, black African Caribbean or Vietnamese completed a measure relating to their experiences and their expectations of the general practice consultation in terms of treatment, communication, patients' agenda, patients' choice and doctor consistency. Results No differences were found for the black African or black African Caribbean patients. The Vietnamese patients reported better experiences of communication, more focus on their agenda and more attention to their choices than the white British patients. However, they also reported expecting lower levels of communication, less focus on their own agenda and reported wanting less GP consistency than the other ethnic groups. Conclusion Vietnamese patients state that they are receiving better standards of care in general practice than other ethnic groups. However, they also state that they expect less. This may illustrate a problem with assessing experiences of primary care. Higher scores of experience may not illustrate better consultations as such, but only better when compared with a lower level of initial expectation. A lower expectation is easier to fulfil. PMID:15904553

  18. Comparison of 12-step groups to mutual help alternatives for AUD in a large, national study: Differences in membership characteristics and group participation, cohesion, and satisfaction.

    Science.gov (United States)

    Zemore, Sarah E; Kaskutas, Lee Ann; Mericle, Amy; Hemberg, Jordana

    2017-02-01

    Many studies suggest that participation in 12-step groups contributes to better recovery outcomes, but people often object to such groups and most do not sustain regular involvement. Yet, research on alternatives to 12-step groups is very sparse. The present study aimed to extend the knowledge base on mutual help group alternatives for those with an alcohol use disorder (AUD), sampling from large, active, abstinence-focused groups including Women for Sobriety (WFS), LifeRing, and SMART Recovery (SMART). This paper presents a cross-sectional analysis of this longitudinal study, using baseline data to describe the profile and participation characteristics of attendees of these groups in comparison to 12-step members. Data from participants 18 and over with a lifetime AUD (N=651) were collected using Web-based surveys. Members of alternative 12-step groups were recruited in collaboration with group directors, who helped publicize the study by emailing meeting conveners and attendees and posting announcements on social media. A comparison group of current (past-30-day) 12-step attendees was recruited from an online meeting hub for recovering persons. Interested parties were directed to a Webpage where they were screened, and eligible participants completed an online survey assessing demographic and clinical variables; in-person and online mutual help involvement; and group satisfaction and cohesion. Analyses involved comparing those identifying WFS, SMART, and LifeRing as their primary group to 12-step members on the above characteristics. Compared to 12-step members, members of the mutual help alternatives were less religious and generally higher on education and income. WFS and LifeRing members were also older, more likely to be married, and lower on lifetime drug and psychiatric severity; meanwhile, LifeRing and SMART members were less likely to endorse the most stringent abstinence goal. Finally, despite lower levels of in-person meeting attendance, members of all

  19. Episodic memory, concentrated attention and processing speed in aging: A comparative study of Brazilian age groups

    Directory of Open Access Journals (Sweden)

    Rochele Paz Fonseca

    Full Text Available Abstract Neuropsychological studies on the processing of some specific cognitive functions throughout aging are essential for the understanding of human cognitive development from ages 19 to 89. Objectives: This study aimed to verify the occurrence of differences in the processing of episodic memory, concentrated attention and speed of attentional processing among four age groups of adults. Methods: A total of 136 neurologically healthy adults, aged 19-89, with 9 or more years of schooling, took part in the study. Participants were divided according to four age groups: young, middle-aged, elderly and oldest old adults. Subtests of the Brief Neuropsychological Evaluation Instrument (NEUPSILIN were applied for the cognitive assessment. Mean score of corrected answers and of response times were compared between groups by means of a one-way ANOVA test with post-hoc Scheffe procedures and ANCOVA including the co-variables of years of schooling and socio-economical scores. Results: In general, differences in performance were observed from 60 years old on. Only the episodic memory task of delayed recall reflected differences from the age of around 40 onwards and processing speed from around the age of 70 onwards. Thus, differences were found between the age groups regarding their cognitive performance, particularly between young adults and elderly adults, and young adults and oldest old adults. Conclusions: Our research indicates that the middle-aged group should be better analyzed and that comparative cross-sectional studies including only extreme groups such as young and elderly adults are not sufficient.

  20. The Bobath concept in stroke rehabilitation: a focus group study of the experienced physiotherapists' perspective.

    Science.gov (United States)

    Lennon, S; Ashburn, A

    2000-10-15

    The Bobath concept, usually known as neuro-developmental treatment (NDT) in America, is one of the major approaches used to rehabilitate patients following stroke; however since the last publication of Bobath (1990), the concept has been taught via an oral tradition on postgraduate courses. This study therefore aimed to explore with experienced therapists firstly how the Bobath concept had changed since 1990, and secondly what they considered its main theoretical assumptions to be using a focus group research design. Eight peer-nominated expert physiotherapists agreed to participate in two focus groups organized according to specialist interest in either neurology (group A) or elderly care (group B). Therapists were asked to discuss six topics based on a review of published literature. Data analysis involved several readings of verbatim transcriptions, from which key themes and concepts were developed. All therapists agreed on the following core themes defining Bobath: analysis of normal movement, control of tone and facilitation of movement. Neuroplasticity was described as the primary rationale for treatment with therapists using afferent information to target the damaged central nervous system. In addition group A discussed motor learning, whereas group B discussed patient focused goals and relating treatment to function. This study highlighted changes in theory, terminology, and techniques. Tone remained a major problem in the rehabilitation management of the hemiplegic patient; however much attention was also directed towards the musculoskeletal system. Both facilitation of normal movement components and task specific practice using specific manual guidance were considered critical elements of the Bobath concept. For Bobath therapists, physiotherapy has an important impact on both the performance components of movement and functional outcomes. In view of the small numbers involved in this preliminary study, further studies are now needed to determine if these

  1. Diplopia of pediatric orbital blowout fractures: a retrospective study of 83 patients classified by age groups.

    Science.gov (United States)

    Su, Yun; Shen, Qin; Lin, Ming; Fan, Xianqun

    2015-01-01

    Orbital blowout fractures are relatively rare in patients under 18 years of age, but may lead to serious complications. We conducted this retrospective study to evaluate diplopia, clinical characteristics, and postoperative results in cases of orbital blowout fractures in the pediatric population. Eighty-three patients, all less than 18 years old, with orbital blowout fractures, were divided into 3 groups by age: 0 to 6 years old, 7 to 12 years old, and 13 to 18 years old. The cause of injury, fracture locations, diplopia grades, ocular motility restrictions, enophthalmos, and postoperative results were reviewed from their records. Chi-square tests, Fisher's exact analyses, analyses of variance, and logistic regressions were performed to determine characteristics associated with diplopia, and to identify factors related to residual diplopia in pediatric patients. The most common causes of injuries were traffic accidents in the 0 to 6 years old group, normal daily activities in the 7 to 12 years old group, and assaults in the 13 to 18 years old group. Floor fractures were the most common location in both the 0 to 6- and 7 to 12 years old groups, and medial-floor fractures were the most common location in the 13 to 18 years old group. The occurrence of preoperative diplopia was related to ocular motility restriction and enophthalmos, but not with the age group, the gender, the cause of injury, or the fracture locations. The time interval from injury to surgery was significant in the outcome of postoperative diplopia (P diplopia among the 3 age groups (P diplopia after surgery.

  2. Medico-legal reasoning in disability assessment: A focus group and validation study

    Directory of Open Access Journals (Sweden)

    Rus M

    2008-09-01

    Full Text Available Abstract Background Decisions on disability pensions are based, among others, on medical reports. The way these medical assessments are performed is largely unclear. The aim of the study was to determine which grounds are used by social insurance physicians (SIPs in these assessments and to determine if the identification of these grounds can help improve the quality of assessments in social insurance practice. The article describes a focus group study and a questionnaire study with SIPs in four different countries. Method Using focus group discussions of SIPs discussing the same case in Belgium, the Netherlands, Norway and Slovenia (N = 29 we determined the arguments and underlying grounds as used by the SIP's. We used a questionnaire study among other SIPs (N = 60 in the same countries to establish a first validation of these grounds. Results Grounds in the focus groups were comparable between the countries studied. The grounds were also recognized by SIPs who had not participated in the focus groups. SIPs agreed most on grounds with regard to the claimant's health condition, and about the claimant's duty to explore rehabilitation and work resumption, but less on accepting permanent incapacity when all options for treatment were exhausted. Conclusion Grounds that SIPs use refer to a limited group of key elements of disability evaluation. SIPs interpret disability in social insurance according to the handicapped role and strive at making their evaluation fair trials. ICF is relevant with regard to the health condition and to the process of evaluation. Identification of grounds is a valuable instrument for controlling the quality of disability evaluation. The grounds also appear to be internationally comparable which may enhance scientific study in this area.

  3. Hypertension management initiative prospective cohort study: comparison between immediate and delayed intervention groups.

    Science.gov (United States)

    Tobe, S W; Moy Lum-Kwong, M; Von Sychowski, S; Kandukur, K; Kiss, A; Flintoft, V

    2014-01-01

    The Heart and Stroke Foundation of Ontario's Hypertension Management Initiative (HMI) was a pragmatic implementation of clinical practice guidelines for hypertension management in primary care clinics. The HMI was a prospective delayed phase cohort study of 11 sites enrolling patients in two blocks starting 9 months apart in 2007. The intervention was an evidence-informed chronic disease management program consisting of an interprofessional educational intervention with practice tools to implement the Canadian Hypertension Education Program's clinical practice guidelines. This study compares the change in blood pressure (BP) from baseline to 9 months after the intervention between groups. In the immediate intervention group, the mean BP at baseline was 134.6/79.1 mm Hg (18.2/11.5) and in the delayed intervention group 134.2/77.1 mm Hg (18.9/11.8). The fall in BP in the immediate intervention group from baseline to 9 months after the intervention was 7.3/3.6 mm Hg (95% confidence interval (CI): 5.9-8.7/2.6-4.5) and in the delayed group 8.1/3.3 mm Hg (95% CI: 7.0-9.3/2.5-4.1) (all Phypertension can rapidly lead to lower BP levels.

  4. Evaluation of group homogeneity during acupuncture stimulation in fMRI studies.

    Science.gov (United States)

    Sun, Jinbo; Qin, Wei; Dong, Minghao; Yuan, Kai; Liu, Jixin; Liu, Peng; Zhang, Yi; von Deneen, Karen M; Tian, Jie

    2010-08-01

    To evaluate the extent of individual differences of functional MRI (fMRI) signal changes induced by acupuncture stimulation. Acupuncture at ST36 and checkerboard stimulation was applied to 16 subjects. We calculated the mean distance using beta values in a generalized linear model (GLM) analysis and employed it to study the group homogeneity by detecting the outliers. A more significant individual difference was presented in acupuncture stimulation compared with visual stimulation through evaluation of the mean distance. From the group results, we found that the activations were more significant in the homogeneous group results. Combining the behavior and fMRI results, there was no direct correlation between deqi index and mean distance in acupuncture stimulation. The deqi index of the outlier was in the normal range and did not differ significantly from others. Traditional group results without removing outliers were not sensitive enough to detect the real acupuncture effect. We suggest that individual difference should be taken into consideration for future acupuncture studies. Also, group analysis paralleled with individual analysis is critical for a full understanding of acupuncture effects. 2010 Wiley-Liss, Inc.

  5. A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups

    CERN Document Server

    Maldonado, J; Eiroa, C; Montes, D; Montesinos, B; 10.1051/0004-6361/201014948

    2010-01-01

    Nearby late-type stars are excellent targets for seeking young objects in stellar associations and moving groups. The origin of these structures is still misunderstood, and lists of moving group members often change with time and also from author to author. Most members of these groups have been identified by means of kinematic criteria, leading to an important contamination of previous lists by old field stars. We attempt to identify unambiguous moving group members among a sample of nearby-late type stars by studying their kinematics, lithium abundance, chromospheric activity, and other age-related properties. High-resolution echelle spectra ($R \\sim 57000$) of a sample of nearby late-type stars are used to derive accurate radial velocities that are combined with the precise Hipparcos parallaxes and proper motions to compute galactic-spatial velocity components. Stars are classified as possible members of the classical moving groups according to their kinematics. The spectra are also used to study several a...

  6. An Empirical Study of Hospitality Management Student Attitudes toward Group Projects: Instructional Factors and Team Problems

    Science.gov (United States)

    Choi, Youngsoo; Ro, Heejung

    2012-01-01

    The development of positive attitudes in team-based work is important in management education. This study investigates hospitality students' attitudes toward group projects by examining instructional factors and team problems. Specifically, we examine how the students' perceptions of project appropriateness, instructors' support, and evaluation…

  7. Review of The Theoretical and Empirical Study on the Interest Conflict Between City Groups

    Institute of Scientific and Technical Information of China (English)

    Guo; Zeguang; Qian; Fang

    2016-01-01

    The Theoretical and Empirical Study on the Interest Conflict Between City Groups Author:Miao Jianjun Year:2014Publisher:Economy&Management Publishing House ISBN:9787509629482(240 pages,in Chinese)Since the application of the strategy"Rising of Central China,"provinces in China’s central region consecutively released their development

  8. Conceptions of happiness and life satisfaction: An exploratory study in 14 national groups

    NARCIS (Netherlands)

    Joshanloo, Mohsen; Rizwan, Muhammad; Khilji, Imran Ahmed; Ferreira, Maria Cristina; Poon, Wai-Ching; Sundaram, Suresh; Ho, Lok Sang; Yeung, Victoria Wai Lan; Han, Gyuseog; Bae, Jaechang; Demir, Meliksah; Achoui, Mustapha; Pang, Joyce S.; Jiang, Ding-Yu; Lamers, Sanne M.A.; Turan, Yücel; Lepshokova, Zarina Kh.; Panyusheva, Tatiana; Natalia, Amerkhanova; Asano, Ryosuke; Igarashi, Tasuku; Tsukamoto, Saori

    2016-01-01

    This study examined the relationship between 4 conceptions of happiness and life satisfaction in a sample of 2715 university students across 14 national groups. The 4 conceptions were self-transcendence, self-directed hedonism, conservation, and self-enhancement, which emerged from a principal compo

  9. Emotional coping differences among breast cancer patients from an online support group: A longitudinal study

    NARCIS (Netherlands)

    Batenburg, A.E.; Das, H.H.J.

    2014-01-01

    Background: Previous research on the effects of online peer support on psychological well-being of patients with cancer showed mixed findings. There is a need for longitudinal studies explaining if and when online peer-led support groups are beneficial. How patients cope with emotions that come

  10. Segregated Groups or Inclusive Education? An Interview Study with Students Experiencing Failure in Reading and Writing

    Science.gov (United States)

    Mattson, Eva Heimdahl; Roll-Pettersson, Lise

    2007-01-01

    In this study a group of students with reading and writing difficulties relate their experiences of school to their expressed opinions concerning the possibilities of participation and influence in this setting. Twelve students at upper-level compulsory school or upper secondary school were interviewed. Mostly their reading and writing…

  11. Group 3 metal stilbene complexes: Synthesis, reactivity, and electronic structure studies

    OpenAIRE

    Huang, W.; Abukhalil, PM; Khan, SI; Diaconescu, PL

    2014-01-01

    Group 3 metal (E)-stilbene complexes supported by a ferrocene diamide ligand were synthesized and characterized. Reactivity studies showed that they behave similar to analogous naphthalene complexes. Experimental and computational results indicated that the double bond was reduced and not a phenyl ring, in contrast to a previously reported uranium (E)-stilbene complex. © the Partner Organisations 2014.

  12. Library on the Go: A Focus Group Study of the Mobile Web and the Academic Library

    Science.gov (United States)

    Seeholzer, Jamie; Salem, Joseph A., Jr.

    2011-01-01

    This study explores student use of the mobile Web in general and expectations for an academic library's mobile Web site in particular through focus groups with students at Kent State University. Participants expressed more interest in using their mobile Web device to interact with library resources and services than anticipated. Results showed an…

  13. Identifying target groups for the prevention of depression in early adolescence : The TRAILS study

    NARCIS (Netherlands)

    Monshouwer, K.; Smit, F.; Ruiter, M.; Ormel, Johan; Verhulst, F.; Vollebergh, W.; Oldehinkel, T.

    Background: Depression in adolescence is associated with long-term adverse consequences. The aim of the present study is to identify target groups at increased risk of developing depression in early adolescence, such that prevention is associated with the largest health benefit at population-level

  14. A Qualitative Study of the Experience of Parents Attending a Psychoanalytically Informed Parent-Toddler Group

    Science.gov (United States)

    Barros, Maria; Kitson, Annabel; Midgley, Nick

    2008-01-01

    The paper presents the findings of a qualitative study into the experience of seven parents attending a psychoanalytically informed parent-toddler group. Semi-structured interviews were carried out with each parent, and analysed using Interpretative Phenomenological Analysis. Analysis of the interviews led us to three "superordinate…

  15. Chair Report Consultancy Meeting on Nuclear Security Assessment Methodologies (NUSAM) Transport Case Study Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Shull, Doug [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-08-19

    The purpose of the consultancy assignment was to (i) apply the NUSAM assessment methods to hypothetical transport security table top exercise (TTX) analyses and (ii) document its results to working materials of NUSAM case study on transport. A number of working group observations, using the results of TTX methodologies, are noted in the report.

  16. Career Repertoires of IT Students: A Group Counselling Case Study in Higher Education

    Science.gov (United States)

    Penttinen, Leena; Vesisenaho, Mikko

    2013-01-01

    Uncertainty about future career prospects has increased enormously for students enrolled in higher education Information Technology (IT) programs. However, many computer science programmes pay little attention to career counselling. This article reports the results of a pilot study intended to develop group counselling for IT students to promote…

  17. Holland's Vocational Models: A Study of Work Groups and Need Satisfaction

    Science.gov (United States)

    Lacey, David W.

    1971-01-01

    This study investigated: (1) the concurrent validity of Holland's theory for employed men; and (2) the pattern of needs associated with occupations exemplifying each of Holland's models. Five vocational scales distributed eight work groups, representative of each of Holland's vocational models, in a comparable fashion according to their interests.…

  18. Developing Reflective Dispositions through Collaborative Knowledge-Building during Small Group Bible Study

    Science.gov (United States)

    Toh, Tze Keong; Koh, Joyce Hwee Ling; Chai, Ching Sing

    2017-01-01

    This article explores the use of a constructivist pedagogical approach to cultivate reflective dispositions during small group Bible study. Conducted in a local church Bible class setting (n = 12), the instructional design emulated the reflective thinking process, while adopting collaborative knowledge-building as its pedagogical framework.…

  19. An Empirical Study of Hospitality Management Student Attitudes toward Group Projects: Instructional Factors and Team Problems

    Science.gov (United States)

    Choi, Youngsoo; Ro, Heejung

    2012-01-01

    The development of positive attitudes in team-based work is important in management education. This study investigates hospitality students' attitudes toward group projects by examining instructional factors and team problems. Specifically, we examine how the students' perceptions of project appropriateness, instructors' support, and evaluation…

  20. Group Cohesion and Social Support in Exercise Classes: Results from a Danish Intervention Study

    Science.gov (United States)

    Christensen, Ulla; Schmidt, Lone; Budtz-Jorgensen, Esben; Avlund, Kirsten

    2006-01-01

    This study examines the formation of group cohesion and social support in exercise classes among former sedentary adults, participating in a Danish community-based intervention. Furthermore, the aim is to analyze the impact of this process on exercise activity among the participants. A multimethod approach was used, analyzing both survey data and…

  1. The Role of Discourse in Group Knowledge Construction: A Case Study of Engineering Students

    Science.gov (United States)

    Kittleson, Julie M.; Southerland, Sherry A.

    2004-01-01

    This qualitative study examined the role of discourse (verbal elements of language) and Discourse (nonverbal elements related to the use of language, such as ways of thinking, valuing, and using tools and technologies) in the process of group knowledge construction of mechanical engineering students. Data included interviews, participant…

  2. Cancer patients' perspectives on multidisciplinary team working: an exploratory focus group study.

    Science.gov (United States)

    Lamb, Benjamin W; Jalil, Rozh T; Shah, Sujay; Brown, Katrina; Allchorne, Paula; Vincent, Charles; Green, James S A; Sevdalis, Nick

    2014-01-01

    This qualitative, focus-group study explores what patients understand about the multidisciplinary team (MDT) in cancer care. Participants were positive towards MDT working, and by strengthening the role of nurses in MDT decision-making, the representation of patients' interests can be improved.

  3. Cognitive Behavioral Group Therapy for Mood Management in Individuals with Intellectual Disabilities: A Pilot Study

    Science.gov (United States)

    Ghafoori, Bita; Ratanasiripong, Paul; Holladay, Christina

    2010-01-01

    Individuals with intellectual disabilities (ID) often display mental health symptoms that may benefit from psychotherapy. In this pilot study, a newly designed cognitive behavioral therapy (CBT) group treatment targeting mood difficulties was provided to 8 adults with mild-borderline ID. Assessment occurred at pretreatment, posttreatment, and 4…

  4. A collaborative study of the EDNAP group regarding Y-chromosome binary polymorphism analysis

    DEFF Research Database (Denmark)

    Brion, María; Dupuy, Berit M; Heinrich, Marielle

    2005-01-01

    A collaborative study was carried out by the European DNA Profiling Group (EDNAP) in order to evaluate the performance of Y-chromosome binary polymorphism analysis in different European laboratories. Four blood samples were sent to the laboratories, to be analysed for 11 Y-chromosome single nucle...

  5. Participation in sports groups for patients with cardiac problems : An experimental study

    NARCIS (Netherlands)

    Schaperclaus, G; deGreef, M; Rispens, P; deCalonne, D; Landsman, M; Lie, KI; Oudhof, J

    1997-01-01

    An experimental study was carried out to determine the influence of participation in Sports Groups for Patients with Cardiac Problems (SPCP) on physical and mental fitness and on risk factor level after myocardial infarction. SPCP members (n = 74; 67 men and 7 women) were compared with Nonsporting P

  6. A Focus Group Study of Child Nutrition Professionals' Attitudes about Food Allergies and Current Training Practices

    Science.gov (United States)

    Lee, Yee Ming; Kwon, Junehee; Sauer, Kevin

    2014-01-01

    Purpose/Objectives: The purpose of this study was to explore child nutrition professionals' (CNPs) attitudes about food allergies, current practices of food allergy training, and operational issues related to food allergy training in school foodservice operations. Methods: Three focus groups were conducted with 21 CNPs with managerial…

  7. The study of personal qualities of the student’s group formal leader

    Directory of Open Access Journals (Sweden)

    Alexander Makarov

    2013-11-01

    Full Text Available Paper is devoted to the study of personal qualities formal leader of the student group. Based on the classification of the key qualities of a modern leader and a suitable model of charismatic leadership were identified criterial quality, suggesting the existence of which was conducted a written survey among students of 1st and 2nd year and the corresponding conclusions.

  8. Teen Perceptions of the Promotion of Safer Sexual Practices: A Focus Group Study

    Science.gov (United States)

    Herrman, Judith W.; Kelley, Andrea; Haigh, Katherine M.

    2017-01-01

    Teens' own thoughts on fostering safe sexual practice are important perspectives in promoting adolescent sexual health yet are relatively absent in the literature. This focus group study explored teens' perceptions about the supports and challenges that exist as teens strive to engage in healthy sexual practices. Seventy-five teens participated in…

  9. A Classroom-Based Study of Small-Group Planned Improvisation with Fifth-Grade Children

    Science.gov (United States)

    Beegle, Amy C.

    2010-01-01

    The purpose of this study was to examine and describe children's music improvisations and the interactions that transpired within their four-person groups during regular weekly music classes as they planned and performed music improvisations in response to three different prompts: a poem, a painting, and a musical composition. Participants were…

  10. Teen Perceptions of the Promotion of Safer Sexual Practices: A Focus Group Study

    Science.gov (United States)

    Herrman, Judith W.; Kelley, Andrea; Haigh, Katherine M.

    2017-01-01

    Teens' own thoughts on fostering safe sexual practice are important perspectives in promoting adolescent sexual health yet are relatively absent in the literature. This focus group study explored teens' perceptions about the supports and challenges that exist as teens strive to engage in healthy sexual practices. Seventy-five teens participated in…

  11. Increasing International and Domestic Student Interaction through Group Work: A Case Study from the Humanities

    Science.gov (United States)

    Cruickshank, Ken; Chen, Honglin; Warren, Stan

    2012-01-01

    This article explores the use of group work strategies to increase student interaction and learning. Despite the growing linguistic and cultural diversity in tertiary institutions, there is strong evidence of minimal interaction between "domestic" and "international" students in classrooms and in wider university contexts. This study investigates…

  12. Collaborative Learning in Online Study Groups: An Evolutionary Game Theory Perspective

    Science.gov (United States)

    Chiong, Raymond; Jovanovic, Jelena

    2012-01-01

    Educational benefits of online collaborative group work have been confirmed in numerous research studies. Most frequently cited advantages include the development of skills of critical thinking and problem solving as well as skills of self-reflection and co-construction of knowledge and meaning. However, the establishment and maintenance of active…

  13. National facilities study. Volume 2: Task group on aeronautical research and development facilities report

    Science.gov (United States)

    1994-01-01

    The Task Group on Aeronautics R&D Facilities examined the status and requirements for aeronautics facilities against the competitive need. Emphasis was placed on ground-based facilities for subsonic, supersonic and hypersonic aerodynamics, and propulsion. Subsonic and transonic wind tunnels were judged to be most critical and of highest priority. Results of the study are presented.

  14. A Self-Study Investigation of Using Inquiry Groups in a Professional Development School Context

    Science.gov (United States)

    Garin, Eva; Harper, Mya

    2016-01-01

    Inquiry Group participation for PDS teachers and teacher candidates is one of the signature programs of the Bowie State University PDS Network and provides PDS teachers and teacher candidates the opportunity to collaborate on teaching strategies and methodologies to use in their classrooms. This article uses self-study methodology to explore the…

  15. Career Repertoires of IT Students: A Group Counselling Case Study in Higher Education

    Science.gov (United States)

    Penttinen, Leena; Vesisenaho, Mikko

    2013-01-01

    Uncertainty about future career prospects has increased enormously for students enrolled in higher education Information Technology (IT) programs. However, many computer science programmes pay little attention to career counselling. This article reports the results of a pilot study intended to develop group counselling for IT students to promote…

  16. Cryptographic Research and NSA: Report of the Public Cryptography Study Group.

    Science.gov (United States)

    Davida, George I.

    1981-01-01

    The Public Cryptography Study Group accepted the claim made by the National Security Agency that some information in some publications concerning cryptology could be inimical to national security, and is allowing the establishment of a voluntary mechanism, on an experimental basis, for NSA to review cryptology manuscripts. (MLW)

  17. Group dialectical behavior therapy adapted for obese emotional eaters; a pilot study

    NARCIS (Netherlands)

    Roosen, M.A.; Safer, D.; Adler, S.; Cebolla, A.; Strien, T. van

    2012-01-01

    Dialectical Behavior Therapy (DBT) has been shown to effectively target binge eating disorder (BED). This study pilots the effectiveness of group DIVE for obese "emotional eaters" to reduce eating psychopathology and achieve weight maintenance. Thirty-five obese male and female emotional eaters

  18. Continuing To Grow as Language Arts Educators: Focusing on the Importance of Study Groups.

    Science.gov (United States)

    Sanacore, Joseph

    Study groups are both a complement and an alternative to traditional staff development. Becoming a community of adult learners is a complex process involving a number of ingredients: purpose, logistics, resources, transfer of learning, electronic networking, sustenance, and assessment. These ingredients are not meant to take the place of…

  19. Learning science through talk: A case study of middle school students engaged in collaborative group investigation

    Science.gov (United States)

    Zinicola, Debra Ann

    Reformers call for change in how science is taught in schools by shifting the focus towards conceptual understanding for all students. Constructivist learning is being promoted through the dissemination of National and State Science Standards that recommend group learning practices in science classrooms. This study examined the science learning and interactions, using case study methodology, of one collaborative group of 4 students in an urban middle school. Data on science talk and social interaction were collected over 9 weeks through 12 science problem solving sessions. To determine student learning through peer interaction, varied group structures were implemented, and students reflected on the group learning experience. Data included: field notes, cognitive and reflective journals, audiotapes and videotapes of student talk, and audiotapes of group interviews. Journal data were analyzed quantitatively and all other data was transcribed into The Ethnograph database for qualitative analysis. The data record was organized into social and cognitive domains and coded with respect to interaction patterns to show how group members experienced the social construction of science concepts. The most significant finding was that all students learned as a result of 12 talk sessions as evidenced by pre- and post-conceptual change scores. Interactions that promoted learning involved students connecting their thoughts, rephrasing, and challenging ideas. The role structure was only used by students about 15% of the time, but it started the talk with a science focus, created awareness of scientific methods, and created an awareness of equitable member participation. Students offered more spontaneous, explanatory talk when the role structure was relaxed, but did not engage in as much scientific writing. They said the role structure was important for helping them know what to do in the talk but they no longer needed it after a time. Gender bias, status, and early adolescent

  20. Reporting genetic results in research studies: summary and recommendations of an NHLBI working group.

    Science.gov (United States)

    Bookman, Ebony B; Langehorne, Aleisha A; Eckfeldt, John H; Glass, Kathleen C; Jarvik, Gail P; Klag, Michael; Koski, Greg; Motulsky, Arno; Wilfond, Benjamin; Manolio, Teri A; Fabsitz, Richard R; Luepker, Russell V

    2006-05-15

    Prospective epidemiologic studies aid in identifying genetic variants associated with diseases, health risks, and physiologic traits. These genetic variants may eventually be measured clinically for purposes of diagnosis, prognosis, and treatment. As evidence of the potential clinical value of such information accrues, research studies face growing pressure to report these results to study participants or their physicians, even before sufficient evidence is available to support widespread screening of asymptomatic persons. There is thus a need to begin to develop consensus on whether and when genetic findings should be reported to participants in research studies. The National Heart, Lung, and Blood Institute (NHLBI) convened a Working Group on Reporting Genetic Results in Research Studies to discuss if, when, and how genetic information should be reported to study participants. The Working Group concluded that genetic test results should be reported to study participants when the associated risk for the disease is significant; the disease has important health implications such as premature death or substantial morbidity or has significant reproductive implications; and proven therapeutic or preventive interventions are available. Finally, the Working Group recommended procedures for reporting genetic research results and encouraged increased efforts to create uniform guidelines for this activity.

  1. A Sample Vocational Group Guidance Study Based on Ginzberg ve His Associates' Developmental Theory

    Directory of Open Access Journals (Sweden)

    Tuncay Ayas

    2010-12-01

    Full Text Available This study was conducted on 12 (6 male 6 female 8th grade students of a primary school in Ankara. The age of the students varied between 14 and 16. Students participated in the study valuntarily after the school counsellor had informed them about it. Sessions were completed in six weeks. Vocational maturity inventory which was developed by Kuzgun and Bacanlı (2005 was administered to group member before and after the program in order to assess the effectiveness of the program. It was found that 6 of the group members did not reach due level of vocational maturity in the pretest, in other words their vocational maturity was low (below 143 points. Three (those between 143-155 points reached the expected vocational maturity level, yet they needed to increase it in order to make a more appropriate vocational decision. The other three  group members (those above 155 points were the ones who had reached the expected vocational maturity.Posttest results showed that two of the group members had not reached the targeted vocational maturity.  One of these students stated that since he would work at the building sector in which his father was working the sessions had not picked up much of his interest and it was observed that he had not attended to two of the group activies. This may be considered as the reason why he did not benefitted from group works.Lack of improvement in other group member's maturity level may be the result of the fact that he will not continue his education after primary school and his reluctance to attend to activities in group sessions. After the implementation of the program, a significant difference was observed between pretest and posttest scores. Mean vocational maturity inventory scores before the program was 145.83 while it increased to 153.25. This finding shows that the study had an important influence on the improvement of vocational maturity by raising group members' vocational maturity inventory scores.

  2. A sample vocational group guidance study based on Ginzberg and his associates' developmental theory

    Directory of Open Access Journals (Sweden)

    Tuncay Ayas

    2010-12-01

    Full Text Available This study was conducted on 12 (6 male 6 female 8th grade students of a primary school in Ankara. The age of the students varied between 14 and 16. Students participated in the study valuntarily after the school counsellor had informed them about it. Sessions were completed in six weeks. Vocational maturity inventory which was developed by Kuzgun and Bacanlı (2005 was administered to group member before and after the program in order to assess the effectiveness of the program. It was found that 6 of the group members did not reach due level of vocational maturity in the pretest, in other words their vocational maturity was low (below 143 points. Three (those between 143-155 points reached the expected vocational maturity level, yet they needed to increase it in order to make a more appropriate vocational decision. The other three groups members (those above 155 points were the ones who had reached the expected vocational maturity.Posttest results showed that two of the group members had not reached the targeted vocational maturity. One of these students stated that since he would work at the building sector in which his father was working the sessions had not picked up much of his interest and it was observed that he had not attended to two of the group activities. This may be considered as the reason why he did not benefitted from group works.Lack of improvement in other group member's maturity level may be the result of the fact that he will not continue his education after primary school and his reluctance to attend to activities in group sessions. After the implementation of the program, a significant difference was observed between pretest and posttest scores. Mean vocational maturity inventory scores before the program was 145.83 while it increased to 153.25. This finding shows that the study had an important influence on the improvement of vocational maturity by raising group members' vocational maturity inventory scores.

  3. Reducing Societal Obesity: Establishing a Separate Exercise Model through Studies of Group Behavior

    Directory of Open Access Journals (Sweden)

    J. S. Puterbaugh

    2016-01-01

    Full Text Available The past 50 years has brought attention to high and increasing levels of human obesity in most of the industrialized world. The medical profession has noticed, has evaluated, and has developed models for studying, preventing, and reversing obesity. The current model prescribes activity in specific quantities such as days, minutes, heart rates, and footfalls. Although decreased levels of activity have come from changes revolving around built environments and social networks, the existing medical model to lower body weights by increasing activity remains individually prescriptive. It is not working. The study of societal obesity precludes the individual and must involve group behavioral studies. Such studies necessitate acquiring separate tools and, therefore, require a significant change in the evaluation and treatment of obesity. Finding groups with common activities and lower levels of obesity would allow the development of new models of land use and encourage active lifestyles through shared interests.

  4. Effective small group teaching strategies for research supervision - A case study

    Science.gov (United States)

    Pathirana, Assela

    2010-05-01

    UNESCO-IHE's students are unique in several aspects: they are mid-career professionals separated from their last university experience by a number of years in the profession, they are from diverse social and cultural backgrounds, and they often have relatively clear understanding on the diverse problems in the practice of engineering in their respective countries and are focused on solving those. As a result of the diversity in many forms, managing effective groups during the research phase of the UNESCO-IHE master's course pose considerable challenge. In this paper, we present a unique combination of tools and approaches that are employed in managing a small group of students (between five and ten) in one study area, who were working on diverse research topics that had the common denominator of mathematical modelling. We blend a number of traditional (e.g. seminars, group discussions, focused training sessions) and non-traditional (e.g. Using collaboration platforms like WIKI, peer-learning) approaches so that the cohesion of the group in maintained and every member benefits from being a part of the group. Four years of experience with employing this blend of tools on a six-month long master's research programme showed us: The approach motivates the students to perform focusing not only on the end-goal of their research study, but on the process of day to day work that lead to that goal. The students' self-confidence is often enhanced by being a part of close-knit group. Initial workload of the teacher increases significantly by this approach, but later this is more than compensated by the fact that the teacher has to do little maintain the momentum. Both strong and not so-strong students equally benefit from the approach. A significant number of students develop a keen interest in being involved in research further. (e.g. engaging in doctoral studies.)

  5. Self-help group and the quality of life of patients with multiple sclerosis - Pilot study

    Directory of Open Access Journals (Sweden)

    Anna Eliášová

    2015-12-01

    Full Text Available Aim: The goal of the pilot study was to compare the quality of life of patients with multiple sclerosis in the Presov region with or without the support of a self-help group. Design: The character of this pilot study on patients with MS was related to the use of self-help groups and their impact on the assessment of the quality of life of the respondents, with the help of a questionnaire (WHOQOL-BREF. Methods: The research was carried out in the Prešov region with the help of the standardized WHOQOL-BREF questionnaire. Ninety-one patients with MS participated in the pilot study (46 respondents attended a self-help group and 35 did not. Results: The groups, when compared, aided by the statistically evaluated WHOQOL-BREF domains, were found to show significant differences in their evaluation of quality of life in three domains: domain one: physical health; domain two: surviving; domain three: social relations. Better scores were achieved in these domains by those who attended a group. In the physical sphere, we noticed significant differences in sleep quality, and sexual satisfaction (p < 0.001, while in social and economic areas, there were significant differences in satisfaction with personal relationships (p < 0.001, and economic circumstances (p < 0.01, self-contentment (p < 0.01, and coping with negative feelings (p < 0.05. Conclusion: Patients with multiple sclerosis can live normal lives provided they are supported by their families, friends, health care professionals, and self-help groups.

  6. Study on the Process of Gender Identification : Process by Children in Kindergarten Peer Groups

    OpenAIRE

    大滝, 世津子; Setsuko, OHTAKI; 東京大学大学院; Graduate School, The University of Tokyo

    2006-01-01

    The purpose of this study is to examine the relationship between the formation of groups in kindergarten and the process of gender identification by children through their kindergarten life. In the field of sociology of education in Japan, there have been some studies on the process of gender identification. However, they have focused on the intensification process of gender categories, but tended to ignore the trigger that leads children to recognize their own "correct" gender, and how they ...

  7. A Case Study of Markdale High School's Implementation of Heterogeneously-Grouped Classes in English, Mathematics, Science, and Social Studies

    Science.gov (United States)

    Pierre-Louis, Fred

    2010-01-01

    The purpose of this study was to describe Markdale High School's change from separate college preparatory and general level classes to heterogeneously-grouped classes in English, mathematics, science, and social studies, with particular emphasis on the principal's leadership style, change process, and teacher concerns (Hall & Hord, 2006)…

  8. A mindful eating group as an adjunct to individual treatment for eating disorders: a pilot study.

    Science.gov (United States)

    Hepworth, Natasha S

    2011-01-01

    The objective of this study was to investigate potential benefits of a Mindful Eating Group as an adjunct to long-term treatment for a variety of eating disorders. Individuals (N = 33) attending treatment at an outpatient treatment facility participated in the 10-week intervention designed to enhance awareness around hunger and satiety cues. Disordered eating symptoms were assessed pre- and post-intervention using the EAT-26. Significant reductions were found on all subscales of the EAT-26 with large effect sizes. No significant differences were identified between eating disorder diagnoses. Results suggest potential benefits of an adjunct mindfulness group intervention when treating a variety of eating disorders. Limitations are discussed.

  9. Teaching Emotional Intelligence: A Control Group Study of a Brief Educational Intervention for Emergency Medicine Residents

    Directory of Open Access Journals (Sweden)

    Diane L. Gorgas

    2015-11-01

    Full Text Available Introduction: Emotional Intelligence (EI is defined as an ability to perceive another’s emotional state combined with an ability to modify one’s own. Physicians with this ability are at a distinct advantage, both in fostering teams and in making sound decisions. Studies have shown that higher physician EI’s are associated with lower incidence of burn-out, longer careers, more positive patient-physician interactions, increased empathy, and improved communication skills. We explored the potential for EI to be learned as a skill (as opposed to being an innate ability through a brief educational intervention with emergency medicine (EM residents. Methods: This study was conducted at a large urban EM residency program. Residents were randomized to either EI intervention or control groups. The intervention was a two-hour session focused on improving the skill of social perspective taking (SPT, a skill related to social awareness. Due to time limitations, we used a 10-item sample of the Hay 360 Emotional Competence Inventory to measure EI at three time points for the training group: before (pre and after (post training, and at six-months post training (follow up; and at two time points for the control group: pre- and follow up. The preliminary analysis was a four-way analysis of variance with one repeated measure: Group x Gender x Program Year over Time. We also completed post-hoc tests. Results: Thirty-three EM residents participated in the study (33 of 36, 92%, 19 in the EI intervention group and 14 in the control group. We found a significant interaction effect between Group and Time (p<0.05. Post-hoc tests revealed a significant increase in EI scores from Time 1 to 3 for the EI intervention group (62.6% to 74.2%, but no statistical change was observed for the controls (66.8% to 66.1%, p=0.77. We observed no main effects involving gender or level of training. Conclusion: Our brief EI training showed a delayed but statistically significant

  10. A CASE STUDY OF PROSODIC PHRASAL GROUPING AND INTONATIONAL PROMINENCE IN LANGUAGE ACQUISITION

    Directory of Open Access Journals (Sweden)

    Susanto

    2016-06-01

    Full Text Available In language acquisition, children use prosody in their comprehension and production of utterances. In line with that, as a case study in this research, I analyze two particular aspects of prosody in a child’s language acquisition, i.e. prosodic phrasal grouping and intonational prominence. In the first aspect, I investigate whether the child uses prosodic phrases to group words together into interpretable units. In the second aspect, I analyze whether the child uses intonational prominence to focus marking prosody. The result indicates that both aspects are used by the child.

  11. Study on vibrational modes by group theory and infrared spectra by D FT for calcite crystal

    Institute of Scientific and Technical Information of China (English)

    Danhua Lou; Fengjiu Sun; Lijuan Li

    2007-01-01

    The factor group symmetry analysis (FSA) method and position symmetry analysis (PSA) method are used to analyze the vibrational modes of calcite (CaCO3) crystal, respectively. With the activated results of infrared and Raman spectra presented, strong points of each method are concluded. The infrared spectra are studied by using dynamics calculations based on density-functional theory (DFT) with the supercell model of calcite crystal. The frequencies of 27 normal modes are achieved, which are consistent with that by the group symmetry analysis very well, and fit with the experimental results better than the lattice dynamical methods.

  12. NASA ExoPAG Study Analysis Group 11: Preparing for the WFIRST Microlensing Survey

    CERN Document Server

    Yee, Jennifer C; Barry, Richard K; Bennett, David; Bryden, Geoff; Chung, Sun-Ju; Gaudi, B Scott; Gehrels, Neil; Gould, Andrew; Penny, Matthew T; Rattenbury, Nicholas; Ryu, Yoon-Hyun; Skowron, Jan; Street, Rachel; Sumi, Takahiro

    2014-01-01

    NASA's proposed WFIRST-AFTA mission will discover thousands of exoplanets with separations from the habitable zone out to unbound planets, using the technique of gravitational microlensing. The Study Analysis Group 11 of the NASA Exoplanet Program Analysis Group was convened to explore scientific programs that can be undertaken now, and in the years leading up to WFIRST's launch, in order to maximize the mission's scientific return and to reduce technical and scientific risk. This report presents those findings, which include suggested precursor Hubble Space Telescope observations, a ground-based, NIR microlensing survey, and other programs to develop and deepen community scientific expertise prior to the mission.

  13. Teaching Emotional Intelligence: A Control Group Study of a Brief Educational Intervention for Emergency Medicine Residents.

    Science.gov (United States)

    Gorgas, Diane L; Greenberger, Sarah; Bahner, David P; Way, David P

    2015-11-01

    Emotional Intelligence (EI) is defined as an ability to perceive another's emotional state combined with an ability to modify one's own. Physicians with this ability are at a distinct advantage, both in fostering teams and in making sound decisions. Studies have shown that higher physician EI's are associated with lower incidence of burn-out, longer careers, more positive patient-physician interactions, increased empathy, and improved communication skills. We explored the potential for EI to be learned as a skill (as opposed to being an innate ability) through a brief educational intervention with emergency medicine (EM) residents. This study was conducted at a large urban EM residency program. Residents were randomized to either EI intervention or control groups. The intervention was a two-hour session focused on improving the skill of social perspective taking (SPT), a skill related to social awareness. Due to time limitations, we used a 10-item sample of the Hay 360 Emotional Competence Inventory to measure EI at three time points for the training group: before (pre) and after (post) training, and at six-months post training (follow up); and at two time points for the control group: pre- and follow up. The preliminary analysis was a four-way analysis of variance with one repeated measure: Group x Gender x Program Year over Time. We also completed post-hoc tests. Thirty-three EM residents participated in the study (33 of 36, 92%), 19 in the EI intervention group and 14 in the control group. We found a significant interaction effect between Group and Time (p≤0.05). Post-hoc tests revealed a significant increase in EI scores from Time 1 to 3 for the EI intervention group (62.6% to 74.2%), but no statistical change was observed for the controls (66.8% to 66.1%, p=0.77). We observed no main effects involving gender or level of training. Our brief EI training showed a delayed but statistically significant positive impact on EM residents six months after the

  14. The effects of group size and group economic factors on collaboration: a study of the financial performance of rural hospitals in consortia.

    Science.gov (United States)

    Chan, B; Feldman, R; Manning, W G

    1999-04-01

    To determine factors that distinguish effective rural hospital consortia from ineffective ones in terms of their ability to improve members' financial performance. Two questions in particular were addressed: (1) Do large consortia have a greater collective impact on their members? (2) Does a consortium's economic environment determine the degree of collective impact on members? Based on the hospital survey conducted during February 1992 by the Robert Wood Johnson Hospital-Based Rural Health Care project of rural hospital consortia. The survey data were augmented with data from Medicare Cost Reports (1985-1991), AHA Annual Surveys (1985-1991), and other secondary data. Dependent variables were total operating profit, cost per adjusted admission, and revenue per adjusted admission. Control variables included degree of group formalization, degree of inequality of resources among members (group asymmetry), affiliation with other consortium group(s), individual economic environment, common hospital characteristics (bed size, ownership type, system affiliation, case mix, etc.), year (1985-1991), and census region dummies. All dependent variables have a curvilinear association with group size. The optimum group size is somewhere in the neighborhood of 45. This reveals the benefits of collective action (i.e., scale economies and/or synergy effects) and the issue of complexity as group size increases. Across analyses, no strong evidence exists of group economic environment impacts, and the environmental influences come mainly from the local economy rather than from the group economy. There may be some success stories of collaboration among hospitals in consortia, and consortium effects vary across different collaborations. When studying consortia, it makes sense to develop a typology of groups based on some performance indicators. The results of this study imply that government, rural communities, and consortium staff and steering committees should forge the consortium

  15. Quality evaluation of value sets from cancer study common data elements using the UMLS semantic groups

    Science.gov (United States)

    Solbrig, Harold R; Chute, Christopher G

    2012-01-01

    Objective The objective of this study is to develop an approach to evaluate the quality of terminological annotations on the value set (ie, enumerated value domain) components of the common data elements (CDEs) in the context of clinical research using both unified medical language system (UMLS) semantic types and groups. Materials and methods The CDEs of the National Cancer Institute (NCI) Cancer Data Standards Repository, the NCI Thesaurus (NCIt) concepts and the UMLS semantic network were integrated using a semantic web-based framework for a SPARQL-enabled evaluation. First, the set of CDE-permissible values with corresponding meanings in external controlled terminologies were isolated. The corresponding value meanings were then evaluated against their NCI- or UMLS-generated semantic network mapping to determine whether all of the meanings fell within the same semantic group. Results Of the enumerated CDEs in the Cancer Data Standards Repository, 3093 (26.2%) had elements drawn from more than one UMLS semantic group. A random sample (n=100) of this set of elements indicated that 17% of them were likely to have been misclassified. Discussion The use of existing semantic web tools can support a high-throughput mechanism for evaluating the quality of large CDE collections. This study demonstrates that the involvement of multiple semantic groups in an enumerated value domain of a CDE is an effective anchor to trigger an auditing point for quality evaluation activities. Conclusion This approach produces a useful quality assurance mechanism for a clinical study CDE repository. PMID:22511016

  16. Reference group theory with implications for information studies: a theoretical essay

    Directory of Open Access Journals (Sweden)

    E. Murell Dawson

    2001-01-01

    Full Text Available This article explores the role and implications of reference group theory in relation to the field of library and information science. Reference group theory is based upon the principle that people take the standards of significant others as a basis for making self-appraisals, comparisons, and choices regarding need and use of information. Research that applies concepts of reference group theory to various sectors of library and information studies can provide data useful in enhancing areas such as information-seeking research, special populations, and uses of information. Implications are promising that knowledge gained from like research can be beneficial in helping information professionals better understand the role theory plays in examining ways in which people manage their information and social worlds.

  17. Fossil Galaxy Groups -- Ideal Laboratories for Studying the Effects of AGN Heating

    CERN Document Server

    Jetha, Nazirah N; Raychaudhury, Somak; Sengupta, Chandreyee; Hardcastle, Martin

    2009-01-01

    We present the first of a sample of fossil galaxy groups with pre-existing Chandra and/or XMM-Newton X-ray observations and new or forthcoming low frequency GMRT data -- RXJ1416.4+2315 (z=0.137). Fossil galaxy groups are ideal laboratories for studying feedback mechanisms and how energy injection affects the IGM, since due to the lack of recent merging activity, we expect the IGM to be relatively pristine and affected only by any AGN activity that has occurred in the group. Our Chandra X-ray observations reveal features resembling AGN-inflated bubbles, whilst our GMRT radio data show evidence of extended emission from the central AGN that may be filling the bubble. This has enabled us to estimate the work done by the central AGN, place limits on the rates of energy injection and discuss the nature of the plasma filling the bubble.

  18. Nutrient adequacy during weight loss interventions: a randomized study in women comparing the dietary intake in a meal replacement group with a traditional food group

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    Bovee Vicki

    2007-06-01

    Full Text Available Abstract Background Safe and effective weight control strategies are needed to stem the current obesity epidemic. The objective of this one-year study was to document and compare the macronutrient and micronutrient levels in the foods chosen by women following two different weight reduction interventions. Methods Ninety-six generally healthy overweight or obese women (ages 25–50 years; BMI 25–35 kg/m2 were randomized into a Traditional Food group (TFG or a Meal Replacement Group (MRG incorporating 1–2 meal replacement drinks or bars per day. Both groups had an energy-restricted goal of 5400 kJ/day. Dietary intake data was obtained using 3-Day Food records kept by the subjects at baseline, 6 months and one-year. For more uniform comparisons between groups, each diet intervention consisted of 18 small group sessions led by the same Registered Dietitian. Results Weight loss for the 73% (n = 70 completing this one-year study was not significantly different between the groups, but was significantly different (p ≤ .05 within each group with a mean (± standard deviation weight loss of -6.1 ± 6.7 kg (TFG, n = 35 vs -5.0 ± 4.9 kg (MRG, n = 35. Both groups had macronutrient (Carbohydrate:Protein:Fat ratios that were within the ranges recommended (50:19:31, TFG vs 55:16:29, MRG. Their reported reduced energy intake was similar (5729 ± 1424 kJ, TFG vs 5993 ± 2016 kJ, MRG. There was an improved dietary intake pattern in both groups as indicated by decreased intake of saturated fat (≤ 10%, cholesterol ( Conclusion In this one-year university-based intervention, both dietitian-led groups successfully lost weight while improving overall dietary adequacy. The group incorporating fortified meal replacements tended to have a more adequate essential nutrient intake compared to the group following a more traditional food group diet. This study supports the need to incorporate fortified foods and/or dietary supplements while following an energy

  19. Nutrient adequacy during weight loss interventions: a randomized study in women comparing the dietary intake in a meal replacement group with a traditional food group

    Science.gov (United States)

    Ashley, Judith M; Herzog, Holly; Clodfelter, Sharon; Bovee, Vicki; Schrage, Jon; Pritsos, Chris

    2007-01-01

    Background Safe and effective weight control strategies are needed to stem the current obesity epidemic. The objective of this one-year study was to document and compare the macronutrient and micronutrient levels in the foods chosen by women following two different weight reduction interventions. Methods Ninety-six generally healthy overweight or obese women (ages 25–50 years; BMI 25–35 kg/m2) were randomized into a Traditional Food group (TFG) or a Meal Replacement Group (MRG) incorporating 1–2 meal replacement drinks or bars per day. Both groups had an energy-restricted goal of 5400 kJ/day. Dietary intake data was obtained using 3-Day Food records kept by the subjects at baseline, 6 months and one-year. For more uniform comparisons between groups, each diet intervention consisted of 18 small group sessions led by the same Registered Dietitian. Results Weight loss for the 73% (n = 70) completing this one-year study was not significantly different between the groups, but was significantly different (p ≤ .05) within each group with a mean (± standard deviation) weight loss of -6.1 ± 6.7 kg (TFG, n = 35) vs -5.0 ± 4.9 kg (MRG, n = 35). Both groups had macronutrient (Carbohydrate:Protein:Fat) ratios that were within the ranges recommended (50:19:31, TFG vs 55:16:29, MRG). Their reported reduced energy intake was similar (5729 ± 1424 kJ, TFG vs 5993 ± 2016 kJ, MRG). There was an improved dietary intake pattern in both groups as indicated by decreased intake of saturated fat (≤ 10%), cholesterol (<200 mg/day), and sodium (< 2400 mg/day), with increased total servings/day of fruits and vegetables (4.0 ± 2.2, TFG vs 4.6 ± 3.2, MRG). However, the TFG had a significantly lower dietary intake of several vitamins and minerals compared to the MRG and was at greater risk for inadequate intake. Conclusion In this one-year university-based intervention, both dietitian-led groups successfully lost weight while improving overall dietary adequacy. The group

  20. ABO and Rh (D group distribution and gene frequency; the first multicentric study in India

    Directory of Open Access Journals (Sweden)

    Amit Agrawal

    2014-01-01

    Full Text Available Background and Objectives: The study was undertaken with the objective to provide data on the ABO and Rh(D blood group distribution and gene frequency across India. Materials and Methods: A total of 10,000 healthy blood donors donating in blood banks situated in five different geographical regions of the country (North, South, East and Center were included in the study. ABO and Rh (D grouping was performed on all these samples. Data on the frequency of ABO and Rh(D blood groups was reported in simple numbers and percentages. Results: The study showed that O was the most common blood group (37.12% in the country closely followed by B at 32.26%, followed by A at 22.88% while AB was the least prevalent group at 7.74%. 94.61% of the donor population was Rh positive and the rest were Rh negative. Regional variations were observed in the distribution. Using the maximum likelihood method, the frequencies of the I A , I B and I O alleles were calculated and tested according to the Hardy Weinberg law of Equilibrium. The calculated gene frequencies are 0.1653 for I A (p, 0.2254 for I B (q and 0.6093 for I O (r. In Indian Population, O (r records the highest value followed by B (q and A (p; O > B > A. Conclusion: The study provides information about the relative distribution of various alleles in the Indian population both on a pan-India basis as well as region-wise. This vital information may be helpful in planning for future health challenges, particularly planning with regards to blood transfusion services.