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Selected AbstractsPulpal responses to bacterial contamination following dentin bridging beneath hard-setting calcium hydroxide and self-etching adhesive resin systemDENTAL TRAUMATOLOGY, Issue 2 2008Yuichi Kitasako Class V cavities were prepared on 30 monkey teeth, and the pulps were exposed with a carbide bur through the cavity floor. Each exposed pulp was capped with either DY or 2V. The cavities were restored with a hybrid resin composite. The resin composite was removed at 180 days after capping, and then cavities were left open to the oral environment for 2 weeks to obtain bacteria contamination DY (BDY) and 2V (B2V; n = 10). A non-bacterial-contaminated group capped with DY was used as control. After bacterial challenges, inflammatory cell infiltration, incidence and differentiation of dentin bridges were evaluated histologically. There were significant differences in the presence of inflammatory cell infiltration among all groups (P < 0.05). No moderate or severe inflammatory reaction was found in Group DY. Group BDY showed moderate or severe inflammatory cell infiltration in 50%, and showed four necrotic specimens. Although no statistically significant difference was found in the formation and differentiation of dentin bridges among all groups, tunnel defects in dentin bridges were detected in 70% (DY), 80% (BDY), and 50% (B2V). Group B2V showed a significantly lower presence of inflammatory cell infiltration than Group BDY (P < 0.05). Bonding agent is supposed to seal the exposure site, and the remaining bonding agent on the cavities was effective as the barrier in the dentin bridges after bacterial challenges. [source] Development and application of a flexible controller in yeast fermentations using pO2 cascade controlENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2010Juris Vanags Abstract The development and application of a flexible process controller in fed-batch yeast fermentations using pO2 cascade control was performed. A new algorithm for fed-batch fermentations using pO2 cascade control was developed, the concept of which could be used as a realizable solution in fermentation systems equipped according to the basic configuration. The algorithm is based on the combined influence of pO2 and pH on the substrate feeding intensity. To test and develop this algorithm, Saccharomyces cerevisiae DY 7221 and Candida tropicalis CK-4 fermentations were carried out. As a result of the use of the combined algorithm, the specific growth rate and productivity grew in both fermentations. In this case, the effect of the use of the algorithm was most pronounced in the C. tropicalis fermentation. [source] Color stability of resin matrix restorative materials as a function of the method of light activationEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2004Ralf Janda The purpose was to investigate the influence of curing devices and curing times on the yellow value (b-value) of composites, ormocers and compomers after performing a suntest (EN ISO 7491). Eight samples of Charisma (CH), Durafill (DU), Definite (DE), and Dyract AP (DY) each were light cured with Translux Energy (tungsten halogen light) for 20, 40 or 60 s and with Apollo 95-E (plasma light) for 3, 10 or 20 s. All samples were subjected to a suntest. Before and after the suntest the yellow values (b-values) were determined and the change (,b) was calculated. When cured with Translux Energy for 20 and 40 s DU, CH, and DY revealed significantly negative ,b-values. The b-value of DE remained nearly constant. When cured for 60 s, DU and DE shifted to more yellow while CH and DY still bleached a little. When cured with Apollo 95-E, a dramatic bleaching process of all materials investigated occurred after the suntest (significant negative ,b). It may be concluded that the bleaching of composites, ormocers and compomers depends on (i) the used light curing device and (ii) the chosen curing times. The tungsten halogen light provided highly significantly superior results. [source] Effect of egg proteins on the quality and refrigerated storage life of chicken patties made with broiler-spent hen meat and by-products,INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2007A. Kalaikannan Summary The effects of whole egg powder (WEP), dried albumen (DA), dried yolk (DY) at a 1% level and liquid egg (LE) at a 3.7% level on the quality characteristics and refrigerated storage (4 ± 1 °C) stability of chicken patties made with meat and by-products of broiler-spent hens were evaluated. The addition of egg powders significantly enhanced the emulsion stability (ES) and product yield compared with control and LE. There was a marked increase in moisture content and sensory attributes by the addition of egg powders. During the refrigerated storage (4 ± 1 °C), thio-barbituric acid number (TBARS), aerobic plate count (APC) and psychrophilic count increased in all samples. Incorporation of DA and DY significantly reduced the TBARS number and APC during the storage over control. The addition of DA, DY and WEP significantly lowered the psychrophilic counts. Treated and control patties packaged in LDPE (low-density polyethylene) pouches were acceptable for 20 days and 15 days, respectively. [source] Development and implementation of guidelines in allergic rhinitis , an ARIA-GA2LEN paperALLERGY, Issue 10 2010J. Bousquet To cite this article: Bousquet J, Schünemann HJ, Zuberbier T, Bachert C, Baena-Cagnani CE, Bousquet PJ, Brozek J, Canonica GW, Casale TB, Demoly P, Gerth van Wijk R, Ohta K, Bateman ED, Calderon M, Cruz AA, Dolen WK, Haughney J, Lockey RF, Lötvall J, O'Byrne P, Spranger O, Togias A, Bonini S, Boulet LP, Camargos P, Carlsen KH, Chavannes NH, Delgado L, Durham SR, Fokkens WJ, Fonseca J, Haahtela T, Kalayci O, Kowalski ML, Larenas-Linnemann D, Li J, Mohammad Y, Mullol J, Naclerio R, O'Hehir RE, Papadopoulos N, Passalacqua G, Rabe KF, Pawankar R, Ryan D, Samolinski B, Simons FER, Valovirta E, Yorgancioglu A, Yusuf OM, Agache I, Aït-Khaled N, Annesi-Maesano I, Beghe B, Ben Kheder A, Blaiss MS, Boakye DA, Bouchard J, Burney PG, Busse WW, Chan-Yeung M, Chen Y, Chuchalin AG, Costa DJ, Custovic A, Dahl R, Denburg J, Douagui H, Emuzyte R, Grouse L, Humbert M, Jackson C, Johnston SL, Kaliner MA, Keith PK, Kim YY, Klossek JM, Kuna P, Le LT, Lemiere C, Lipworth B, Mahboub B, Malo JL, Marshall GD, M vale-Manuel S, Meltzer EO, Morais-Almeida M, Motala C, Naspitz C, Nekam K, Niggemann B, Nizankowska-Mogilnicka E, Okamoto Y, Orru MP, Ouedraogo S, Palkonen S, Popov TA, Price D, Rosado-Pinto J, Scadding GK, Sooronbaev TM, Stoloff SW, Toskala E, van Cauwenberge P, Vandenplas O, van Weel C, Viegi G, Virchow JC, Wang DY, Wickman M, Williams D, Yawn BP, Zar HJ, Zernotti M, Zhong N, In collaboration with the WHO Collaborating Center of Asthma and Rhinitis (Montpellier). Development and implementation of guidelines in allergic rhinitis , an ARIA-GA2LEN paper. Allergy 2010; 65: 1212,1221. Abstract The links between asthma and rhinitis are well characterized. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines stress the importance of these links and provide guidance for their prevention and treatment. Despite effective treatments being available, too few patients receive appropriate medical care for both diseases. Most patients with rhinitis and asthma consult primary care physicians and therefore these physicians are encouraged to understand and use ARIA guidelines. Patients should also be informed about these guidelines to raise their awareness of optimal care and increase control of the two related diseases. To apply these guidelines, clinicians and patients need to understand how and why the recommendations were made. The goal of the ARIA guidelines is to provide recommendations about the best management options for most patients in most situations. These recommendations should be based on the best available evidence. Making recommendations requires the assessment of the quality of available evidence, deciding on the balance between benefits and downsides, consideration of patients' values and preferences, and, if applicable, resource implications. Guidelines must be updated as new management options become available or important new evidence emerges. Transparent reporting of guidelines facilitates understanding and acceptance, but implementation strategies need to be improved. [source] Opposing roles of IL-17A and IL-25 in the regulation of TSLP production in human nasal epithelial cellsALLERGY, Issue 5 2010G. Xu To cite this article: Xu G, Zhang L, Wang DY, Xu R, Liu Z, Han DM, Wang XD, Zuo KJ, Li HB. Opposing roles of IL-17A and IL-25 in the regulation of TSLP production in human nasal epithelial cells. Allergy 2010; 65: 581,589. Abstract Background:, The importance of IL-17A, IL-17F, and IL-25 in allergic rhinitis (AR), as well as their possible role in regulation on thymic stromal lymphopoietin (TSLP) production in nasal epithelial cells, is not well understood. Objective:, To determine the possible regulation of IL-17A, IL-17F, and IL-25 on TSLP production in the initiation of allergic responses. Methods:, The levels of IL-17A, IL-17F, IL-25, and TSLP in nasal lavages of patients with AR were measured using an enzyme-linked immunosorbent assay (ELISA) and compared with that in normal controls. Then, primary human nasal epithelial cells (HNECs) were stimulated with dsRNA (0,75 ,g/ml), as well as IL-17A (100 ng/ml), IL-17F (100 ng/ml), and IL-25(100 ng/ml). The mRNA expression of IL-17A, IL-17F, IL-25, TSLP, as well as the chemokines CCL20, IL-8, and eotaxin was analyzed using quantitative real-time PCR, and their protein levels in the supernatants of cultured HNECs were determined by ELISA. Results:, Both TSLP and IL-17 cytokines are significantly elevated in patients with AR. dsRNA was found to increase the production of IL-17F, IL-25, TSLP, CCL20, and IL-8 in HNECs. Furthermore, IL-25 significantly enhanced dsRNA-induced TSLP production in primary HNECs and was dominant to the inhibitory effect of IL-17A on TSLP regulation. Conclusions:, Our study provides the first evidence that both IL-17F and IL-25 can be induced by dsRNA in HNECs. Despite of the opposing effects of IL-17A and IL-25 on TSLP regulation in HNECs, IL-25 was dominant to IL-17A, providing a plausible explanation for the simultaneous upregulation of IL-17 cytokines and TSLP in patients with AR. [source] Assessment of post-stroke extrapersonal neglect using a three-dimensional immersive virtual street crossing programACTA NEUROLOGICA SCANDINAVICA, Issue 3 2010D. Y. Kim Kim DY, Ku J, Chang WH, Park TH, Lim JY, Han K, Kim IY, Kim SI. Assessment of post-stroke extrapersonal neglect using a three-dimensional immersive virtual street crossing program Acta Neurol Scand: 2010: 121: 171,177. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objective,,, To investigate the potential of our newly developed three-dimensional immersive virtual reality (VR) program modeled on a real street crossing as an assessment tool for extrapersonal neglect in stroke patients. Methods,,, Thirty-two patients with right-hemispheric stroke (neglect group, 16; non-neglect group, 16) were enrolled. The deviation angle, reaction time, left-to-right reaction time ratio, visual and auditory cue rates, and failure rate were evaluated during missions to keep a virtual avatar safe from a traffic accident in the VR program. The line bisection test and letter cancellation test were also evaluated. Results,,, The deviation angle, left-to-right reaction time ratio, left visual and auditory cue rates and left failure rate in the VR program showed significant differences between the two groups (P < 0.05). Depending on the direction of approach of the virtual car, the left parameters were significantly higher than the right parameters in the neglect group (P < 0.05). In the neglect group, the line bisection test correlated significantly with the deviation angle (P < 0.05). None of the other virtual reality parameters significantly correlated with the paper and pencil tests. Conclusion,,, Post-stroke neglect in the extrapersonal space can be easily and safely detected and measured using our three-dimensional immersive virtual street crossing program. [source] Biopsy Strategies for Endoscopic Surveillance of Pre-malignant Gastric LesionsHELICOBACTER, Issue 4 2010Annemarie C. De Vries Abstract Background:, Endoscopic surveillance of pre-malignant gastric lesions may add to gastric cancer prevention. However, the appropriate biopsy regimen for optimal detection of the most advanced lesions remains to be determined. Therefore, we evaluated the yield of endoscopic surveillance by standardized and targeted biopsy protocols. Materials and Methods:, In a prospective, multi-center study, patients with intestinal metaplasia (IM) or dysplasia (DYS) underwent a surveillance gastroscopy. Both targeted biopsies from macroscopic lesions and 12 non-targeted biopsies according to a standardized protocol (antrum, angulus, corpus, cardia) were obtained. Appropriate biopsy locations and the yield of targeted versus non-targeted biopsies were evaluated. Results:, In total, 112 patients with IM (n = 101), or low-grade (n = 5) and high-grade DYS (n = 6) were included. Diagnosis at surveillance endoscopy was atrophic gastritis (AG) in one, IM in 77, low-grade DYS in two, high-grade DYS in three, and gastric cancer in one patient. The angulus (40%), antrum (35%) and lesser curvature of the corpus (33%) showed the highest prevalence of pre-malignant conditions. Non-targeted biopsies from the lesser curvature had a significantly higher yield as compared to the greater curvature of the corpus in diagnosing AG and IM (p = .05 and p = .03). Patients with extensive intragastric IM, which was also present at the cardia were at high risk of a concurrent diagnosis of dysplasia or gastric cancer. High-grade DYS was detected in targeted biopsies only. Conclusions:, At surveillance endoscopies, both targeted and non-targeted biopsies are required for an appropriate diagnosis of (pre-)malignant gastric lesions. Non-targeted biopsies should be obtained in particular from the antrum, angulus and lesser curvature of the corpus. [source] Vascular endothelial growth factor (VEGF) expression in oral tissues: possible relevance to angiogenesis, tumour progression and field cancerisationJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2001J. Carlile Abstract: The aim of this study was to assess whether vascular endothelial growth factor (VEGF) expression in oral tissues is associated with angiogenesis, disease progression or field cancerisation. Vascularity and VEGF immunoreactivity were quantified in 68 archival specimens including normal oral mucosa (NOM), dysplasia (DYS) and squamous cell carcinoma (SCC). Vascularity increased significantly with disease progression; it was also higher in NOM adjacent to SCC than in NOM from healthy tissue, suggesting an association with field cancerisation. VEGF expression in epithelial cells was evaluated using two antibodies and three indices. VEGF indices and vascularity were not directly correlated. The expression of VEGF was similar in all DYS and NOM specimens, whether or not adjacent to a concurrent lesion. A comparison of SCC with NOM or DYS led to opposite results, depending on the VEGF antibody and index used. We conclude that VEGF expression in the oral mucosa may play a physiological role, but does not appear to be associated with angiogenesis, field cancerisation or transition to dysplasia. Further studies concerned with tumour development require examining specific VEGF isoforms and standardisation of the methodology. [source] Physical properties of Dy and La doped SnO2 thin films prepared by a cost effective vapour deposition techniqueCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2006J. Joseph Abstract Stannous oxide (SnO2) thin film is one of the most widely used n-type transparent semi-conductor films in electronics, electro-optics and solar energy conversion. By achieving controlled non-stoichiometry, we can get good transparency and high electrical conductivity simultaneously in SnO2 thin films. Dy and La doped SnO2 thin films have been prepared by a cost effective vapour deposition technique. The structural, photo-electronic, optical and electrical properties of the doped and undoped films were studied. The results of X-ray Diffraction studies reveals the polycrystalline nature of the films with preferential orientation along the (101), (211) and (301) planes and their average grain size variation for different deposition temperature. Photoconductivity and Photovoltaic studies of the films were also performed. The optical properties of these films were studied by measuring their optical transmission as a function of wavelength. The optical transmission is found to be increased on Dy doping and decreased on La doping. The band gap, refractive index and thickness of the films were calculated from U-V transmittance and Absorption graphs. The optical band gap of undoped film is found to be 4.08 eV, but on doping it shifts to lower energies and then increases on increasing the concentration of both dopants. Its electrical parameters such as sheet resistance, resistivity, mobility, Hall coefficient, and carrier concentration were determined by Four Probe, Van der Pauw and Hall Probe method. On doping with Dy, carrier conversion takes place from n-type to p-type and p-conductivity dominates. On La doping no carrier conversion takes place but resistivity decreases. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Crystal growth features and properties of layered rare earth and barium cobaltatesCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4-5 2005G. L. Bychkov Abstract High quality single crystals of LnBaCo2O5+, (0 < , < 1) (Ln = Pr, Eu, Gd, Tb, Dy) with rectangular shape and average dimensions 5 mm × 5 mm × 1 mm were grown for the first time from overstoichiometric flux melt. The data on the primary crystallization field of most cobaltate phases, which appear in parts of corresponding Gibbs triangles in the range 1373 , 1523 K are discussed. Bulk single crystals of new phases HoBaCo4O7 up to 300 mm3, YBaCo4O7 and TbBaCo4O7 up to 10 mm3 in volume were grown first. A solution of these compounds structure has been found in the space group P63mc. For the Ln = Pr, Gd, Sm, Tb, Dy, Ho based systems under the liquidus line there are several other new cobaltate phases of both perovskite, and hexagonal crystal structure. Stability of the double perovskite phase and temperature of the antiferromagnetic , ferromagnetic phase transition in relation to the radius of rare earth ions are compared. The data on the exact analysis of chemical composition, including EDX and iodometric titration, as well as results on magnetic susceptibility of EuBaCo1- xAlxO5+, (0 < x < 0.3) are discussed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Frameworks by Solvent-Free Synthesis of Rare Earth Chlorides with Molten 1,3-Benzodinitrile and Tailoring of the Particle Size: ,3[LnCl3{1,3-C6H4(CN)2}], Ln = Y, Dy, Ho, Er, YbEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2010Christoph J. Höller Abstract The solvent-free melt reactions of anhydrous rare earth trichlorides with molten 1,3-benzodinitrile [1,3-C6H4(CN)2, C8H4N2] result in isophthalonitrile frameworks of the rare earth elements. The particle size of the products can bevaried from the millimeter to the nanometer scale (down to 50,400 nm) depending on the synthesis conditions. Thus, these network structures are among the very few coordination polymers that can be synthesized as nanoparticles. A constitution of 1:1 concerning LnCl3/1,3-C6H4(CN)2 is found for Y (1), Dy (2), Ho (3), Er (4), and Yb (5) in isotypic,3[LnCl3{1,3-C6H4(CN)2}]. The ligand 1,3-C6H4(CN)2 functions both as chemical scissors and replaces chloride linkages by degrading the rare earth chloride structures, and subsequently forms new 3D-framework structures. They consist of strands of chlorido-coordinated lanthanide atoms, which are linked in two dimensions by 1,3-C6H4(CN)2 molecules. Compounds 1,5 were obtained as single crystals from the melt reaction, and their crystal structures were determined by single-crystal X-ray analysis. They can also be obtained as nanocrystalline materials from a ball mill treatment, identified by electron microscopy (REM) and EDX analysis. [source] The Role of Functionalisation, Asymmetry and Shape of a New Macrocyclic Compartmental Ligand in the Formation of Mononuclear, Homo- and Heterodinuclear Lanthanide(III) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2009Sergio Tamburini Abstract The compartmental [1+1] macrocycle H3L, obtained by self-condensation of the formyl precursor 3,3,-(3,6-dioxaoctane-1,8-diyldioxy)bis(2-hydroxybenzaldehyde) with the amine precursor N,N -bis(2-aminoethyl)-2-hydroxybenzylamine, contains one inner ON3O2 Schiff base and one outer O2O4 crown-like chamber. According to the experimental conditions it forms, by a template process, the stable mononuclear complexes Ln(H3L)(Cl)2(CH3COO)·nS·mHCl or [Ln(L)]·nS (Ln = La, Lu, Y, Yb, Er, Dy, Tb, Gd, Eu, Ce) with the lanthanide(III) ion encapsulated in the crown-ether-like and in the Schiff base site. The mononuclear complexes Ln(H3L)(Cl)2(CH3COO)·nS·mHCl, by further complexation with a different lanthanide(III) ion, give rise to the related heterodinuclear complexes [LnLn,(L)(Cl)2(CH3COO)]·nS while the homodinuclear and the heterodinuclear complexes [Ln2(L)](Cl)3·nH2O and [LnLn,(L)](Cl)3·nS could be prepared by a template reaction using the appropriate molar ratio of reactants. Their properties have been studied by using SEM-EDS microscopy, IR and NMR spectroscopy and their compositions confirmed by thermal and ESI-Mass spectrometric analyses. In the heterodinuclear complexes, the site occupancy of the different lanthanide(III) ions was determined by 1H and 13C NMR spectroscopy in CD3OD or (CD3)2SO , it was found that heterodinuclear complexation occurs in methanol with the smaller lanthanide(III) ion mainly coordinating to the Schiff base site and the larger lanthanide(III) ion to the crown site whereas, in dimethyl sulfoxide, demetalation of the weaker coordinated lanthanide(III) ion into the crown ether chamber occurs with the subsequent formation of mononuclear species in solution. The thermal decomposition of the heterodinuclear complexes forms the related mixed oxides, the stoichiometries and properties of which were determined by SEM-EDS microscopy and X-ray powder diffraction studies (XRD). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Heterometallic CoIII,LnIII (Ln = Gd, Tb, Dy) Complexes on a p -Sulfonatothiacalix[4]arene Platform Exhibiting Redox-Switchable Metal-to-Metal Energy TransferEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2008Viktoriya Skripacheva Abstract Nuclear magnetic relaxation along with pH metric data have been used to reveal pH-dependent heterometallic CoIII,LnIII (Ln = Gd, Tb, and Dy) complex formation on a p -sulfonatothiacalix[4]arene (TCAS) platform in aqueous solution. The previously obtained 1D and 2D 1H NMR spectroscopic and X-ray data prove the outer sphere binding of the CoIII block with the upper rim of TCAS, whereas the LnIII ion is coordinated with the phenolate groups of the lower rim of TCAS. The inclusive outer-sphere binding of CoIII tris(dipyridyl) and tris(ethylendiaminate) complexes with the upper rim of TCAS favors binding of the inner-sphere lanthanide ions through the lower rim of TCAS, whereas noninclusive binding of CoIII bis(histidinate) provides no effect on the binding of lanthanide ions. The emission properties of [Co(dipy)3]3+,LnIII (Ln = Gd, Tb, Dy) complexes indicate the quenching of 4f luminescence by the 3d block. This quenching can be switched off by electrochemical CoIII/CoII reduction with further switching on by reoxidation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Lanthanide-Based Conjugates as Polyvalent Probes for Biological LabelingEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2008Stéphanie Claudel-Gillet Abstract A series of lanthanide complexes of [LnL(H2O)] composition, suitable for biological labeling has been studied, in which L is a strongly chelating ligand containing chromophoric bipyridylcarboxylate units and Ln = Sm, Eu, Gd, Tb, and Dy. For the Gd complex, a combined 17O NMR and 1H NMRD study has been performed. The water exchange rate obtained, kex298 = (5.2,±,0.6),×,106 s,1, is slightly higher than those for [Gd(dota)(H2O)], or [Gd(dtpa)(H2O)]2,. Transformation of the uncoordinated carboxylate function of the ligand into an activated ester ensures covalent linking of the complex to bovine serum albumine (BSA). The relaxivity properties of the Gd complex labeled on BSA revealed a limited increase of both longitudinal and transversal relaxivities. This can be related to the partial replacement of the inner-sphere water molecules by coordinating functions of the protein. Additionally, the Sm and Dy complexes are described and chemically characterized. Their photophysical properties were investigated by means of absorption, steady-state and time-resolved spectroscopy, evidencing efficient photosensitization of the lanthanide emission by ligand excitation (antenna effect). Luminescence lifetime measurements confirmed the presence of a water molecule in the first coordination sphere that partly explained the relatively poor luminescence properties of the Dy and Sm complexes in aqueous solutions. The spectroscopic properties of the series of complexes are questioned in terms of time-resolved acquisition techniques. Finally, their availability for use in time-resolved luminescence microscopy is demonstrated by staining experiments of rat brain slices, where the complex showed enhanced localization in some hydrophilic regions of the blood,brain barrier (BBB).(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis and Reactions of Polynuclear Polyhydrido Rare Earth Metal Complexes Containing "(C5Me4SiMe3)LnH2" Units: A New Frontier in Rare Earth Metal Hydride ChemistryEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2007Zhaomin Hou Abstract A series of tetranuclear octahydrido rare earth metal complexes of general formula [(C5Me4SiMe3)Ln(,-H)2]4(THF)n (Ln = Sc, Y, Gd, Dy, Ho, Er, Tm, Lu; n = 0, 1, or 2) that contain C5Me4SiMe3 as an ancillary ligand have been prepared and structurally characterized. These hydride clusters are soluble in common organic solvents such as THF, toluene, and hexane, and maintain their tetranuclear framework in solution. Such polynuclear polyhydrido complexes exhibit extremely high and unique reactivity toward a variety of unsaturated substrates including CO, CO2, and nitriles. The reaction of these neutral polyhydrides with one equivalent of [Ph3C][B(C6F5)4] affords the corresponding cationic hydride clusters [(C5Me4SiMe3)4Ln4H7(THF)n][B(C6F5)4], which can act as catalysts for the syndiospecific polymerization of styrene and regio- and stereospecific cis -1,4-polymerization of 1,3-cyclohexadiene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Lanthanide Complexes of Disulfoxide Ligands with Varied Configurations: Influence of Lanthanide Contraction on the Structures of the ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2005Jian-Rong Li Abstract Four new disulfoxide-LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3·nH2O with meso -1,3-bis(ethylsulfinyl)propane (meso - L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the LaIII ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2,4 have isostructural dinuclear structures, in which the LnIII ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso -configuration, and monodentate coordination with a rac -configuration. The structural differences between 1 and 2,4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Template Synthesis, Crystal Structure and Luminescent Properties of Neutral N4O3 Tripodal LnIIIL Complexes (LnIII = La3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+ or Lu3+; H3L = Tris{[3,-(2,,-pyridyl)-5,- tert -butyl-2,-hydroxybenzylidene-2-imino]ethyl}amine)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2004Wai-Kwok Wong Abstract In the presence of Ln3+ (Ln = La, Eu, Gd, Tb, Dy, Ho, Er, Tm or Lu), tris(2-aminoethyl)amine condensed with three equivalents of 3-(2,-pyridyl)-5- tert -butyl-2-hydroxybenzaldehyde in methanol to give the neutral Schiff-base complex LnIIIL (Ln = La 1, Eu 2, Gd 3, Tb 4, Dy 5, Ho 6, Er 7, Tm 8 and Lu 9; H3L = tris{[3,-(2,,-pyridyl)-5,- tert -butyl-2,-hydroxybenzylidene-2-imino]ethyl}amine). The structures of compounds 4,7 were determined by X-ray crystallography. The crystal structure analyses revealed that the Schiff base behaves as a tri-deprotonated heptadentate ligand encapsulating the lanthanide metal ion within the N4O3 cavity, with all the pyridyl groups being pendant. Solution spectroscopic data suggest that the LnIIIL complexes remain intact in methanol and exist as nine-coordinate non-electrolytes with the lanthanide metal ions coordinated to the N4O3 cavity of the tripodal Schiff base and two solvent molecules. The solution photoluminescent properties of these lanthanide Schiff-base complexes were also examined. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Nitrogen-Rich Compounds of the Lanthanoids: The 5,5,-Azobis[1H -tetrazol-1-ides] of some Yttric Earths (Tb, Dy, Ho, Er, Tm, Yb, and Lu)HELVETICA CHIMICA ACTA, Issue 7 2009Georg Steinhauser Abstract A set of N-rich salts, 3,9, of the heavy lanthanoids (terbium, 3; dysprosium, 4; holmium 5; erbium, 6; thulium, 7; ytterbium, 8; lutetium, 9) based on the energetic 5,5,-azobis[1H -tetrazole] (H2ZT) was synthesized and characterized by elemental analysis, vibrational (IR and Raman) spectroscopy, and X-ray structure determination. The synthesis of the lanthanoid salts 3,9 was performed by crystallization from concentrated aqueous solutions of disodium 5,5,-azobis[1H -tetrazol-1-ide] dihydrate (Na2ZT,2,H2O; 1) and the respective Ln(NO3)3,5,H2O and yielded large rhombic crystals of the type [Ln(H2O)8]2(ZT)3,6,H2O in ca. 70% of the theoretical yield. The compounds 3,9 are isostructural (triclinic space group P) to the previously published yttrium salt 2; they show, however, a clear lanthanoid contraction of several crystallographic parameters, e.g., the cell volume or the LnO bond lengths of the Ln3+ ions and the coordinating H2O molecules. The lanthanoid contraction influences the strengths of the H-bonds, which can be observed as a red shift by 4,cm,1 in the characteristic IR band, in particular from 3595,cm,1 (3) to 3599,cm,1 (9). In good agreement with previous works, 2,9 are purely salt-like compounds without a coordinative bond between the tetrazolide anion and the Ln3+ cation. [source] The Effect of Dopants on the Dielectric Properties of Ba(B,1/2Ta1/2)O3 (B,=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) Microwave CeramicsINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 5 2009Lamrat Abdul Khalam Low-loss dielectric ceramics based on Ba(B,1/2Ta1/2)O3 (B,=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) complex perovskites have been prepared by the solid-state ceramic route. The dielectric properties (,r, Qu, and ,f) of the ceramics have been measured in the frequency range 4,6 GHz by the resonance method. The resonators have a relatively high dielectric constant and high quality factor. Most of the compounds have a low coefficient of temperature variation of the resonant frequencies. The microwave dielectric properties have been improved by the addition of dopants and by solid solution formation. The solid solution Ba[(Y1,xPrx)1/2Ta1/2]O3 has x=0.15, with ,r=33.2, Qu×f=51,500 GHz, and ,f,0. The microwave dielectric properties of Ba(B,1/2Ta1/2)O3 ceramics are found to depend on the tolerance factor (t), ionic radius, and ionization energy. [source] Preparation and thermal decomposition reaction kinetics of a dysprosium(III) p -chlorobenzoate 1,10-phenanthroline complexINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 2 2008Jian Jun Zhang The title complex [Dy(p -ClBA)3Phen]2·2H2O was synthesized, where p -ClBA is p -chlorobenzoate and Phen is 1,10-phenanthroline. The complex was characterized by various techniques including elemental analysis, IR, XRD, and molar conductance. The thermal decomposition of the complex was studied under the nonisothermal condition by TG-DTG and IR techniques. The kinetic parameters of dehydration process were obtained from the analysis of DSC curves of the complex by the NL-DIF and Popescu methods, respectively. © 2007 Wiley Periodicals, Inc. 40: 66,72, 2008 [source] Kinetics of propane oxydehydrogenation on metals oxides and metals phosphates catalysts: Evidence of compensation effectsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2006B. Y. Jibril Kinetics of oxidative dehydrogenation of propane has been tested on three groups of catalysts; alumina-supported metal oxides (MO) (where metal is V, Cr, Ni, Zr, Mo, or Ba), alumina-supported rare earth metal oxides (RO) (where metal is Ce, Tb, Dy, Ho, Tm, or Yb), and metal phosphates (MP) (where metal is V, Cr, Mn, Ni, Zr, Mg, Ba, or Ce). They were found to be active and exhibited different selectivities to propylene, ethylene, and COx (CO and CO2). The Arrhenius parameters,apparent pre-exponential factor (lnAapp) and activation energy Eapp),were evaluated. Evidence of compensation effects was established through statistically significant linear relationship between ln Aapp and Eapp. The rates of propane conversions and COx productions on MO and MP showed common compensation line different from that of RO. When the data for rates of production of propylene and ethylene were plotted, the line for the ethylene rate on MO appeared above that of propylene rate, contrary to the observation on MP and RO. An attempt was made to associate the differences in the behaviors of the catalysts with differences in the ensembles of chemisorbed species that form the respective active centers. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 176,183, 2006 [source] [5-(p -alkoxy)phenyl-10, 15, 20-tri-phenyl] porphyrin and their rare earth complex liquid crystallineJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2007Miao Yu Abstract Three series of porphyrin liquid crystalline compounds, [5-(p -alkoxy)phenyl-10, 15, 20-tri-phenyl] porphyrin and their rare earth complexes (Tb (III), Dy (III), Er (III), Yb (III)), with a hexagonal columnar discotic columnar(Colh) phase have been synthesized. These compounds were characterized by elemental analysis, molar conductances, UV-visible spectra, infrared spectra, luminescence spectra, and cyclic voltammetry. These compounds exhibit more than one mesophases, which transition points of temperature change from ,33.6 to 16.0,°C, and transition points of temperature for isotropic liquid also increase from 4.9 to 38.2,°C, with increasing chain length. Their surface photovoltage (SPV) response have also been investigated by the means of surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (EFISPS). It was found that their SPV bands are analogous with the UV-visible absorption spectra and derived from the same transition. Copyright © 2007 John Wiley & Sons, Ltd. [source] Temperature-dependent Raman scattering studies of the geometrically frustrated pyrochlores Dy2Ti2O7, Gd2Ti2O7 and Er2Ti2O7JOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2008M. Ma, czka Abstract The temperature-dependent Raman studies of A2Ti2O7(A = Dy, Er, Gd) were performed on single crystals and polycrystalline samples in the 4.2,295 K temperature range. The Raman spectra showed softening of the majority of phonon modes upon cooling in the whole temperature range studied and large decrease of linewidths. These changes have been analyzed in terms of strong third-order phonon,phonon anharmonic interactions. Moreover, the 312 and 330 cm,1 modes of Er2Ti2O7(Gd2Ti2O7) showed hardening upon cooling down to about 130 K (100 K) and then anomalous softening below this temperature. The observed anomalous behavior of the Raman modes indicates that some important changes occur in these materials at low temperatures. However, the origin of this behavior is still not clear. Copyright © 2008 John Wiley & Sons, Ltd. [source] Ion imprinted polymer particles for separation of yttrium from selected lanthanidesJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9 2006Ramakrishnan Kala Abstract Lanthanide(III) (Dy, Gd, Tb and Y) ion imprinted polymer (IIP) materials were synthesized via single pot reaction by mixing lanthanide imprint ion with 5,7-dichloroquinoline-8-ol, 4-vinylpyridine, styrene, divinylbenzene and 2,2,-azobisisobutyronitrile in 2-methoxyethanol porogen. The imprint ion was removed by stirring the above materials (after powdering) with 6 mol/L HCl to obtain the respective lanthanide IIP particles. Y-Dy, Y-Gd and Dy-Gd polymer particles were obtained by physically mixing equal amounts of the respective leached individual lanthanide(III) particles. Control polymer (CP) particles were similarly prepared without imprint ion. Application of the above synthesized polymer particles was tested for separation of Y from Dy, Gd and Tb employing batch and column SPE methods using inductively coupled plasma atomic emission spectrometry for the determination. Optimization studies show that Y present in 500 mL can be preconcentrated using Dy-Gd IIP particles and eluted with 20 mL of 1.0 mol/L of HCl, providing an enrichment factor of , 25. Dy-Gd IIP particles offer higher selectivity coefficients for Y over other lanthanides compared to other IIP particles and commercial liquid,liquid extractants. Selectivity studies for Y over other coexisting inorganic species (other than lanthanides) were also conducted and the results obtained show a quantitative separation of Y from other inorganics other than Cu(II) and Fe(III). Furthermore, both batch and column studies indicate the purification of yttrium concentrate from 55.0 ± 0.2 to 65.2 ± 0.2% in a single stage of operation. [source] Microwave Dielectric Properties of SrRE4Si3O13 (RE=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, and Y) CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2009Sherin Thomas The apatite type SrRE4Si3O13 (RE=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb, and Y) ceramics have been prepared by the conventional solid-state ceramic route. The phase purity and surface morphology of the sintered ceramics were studied using X-ray diffraction and scanning electron microscopy methods. These materials showed poor sinterability and was improved by the addition of a small weight percentage of zinc borosilicate glass. The microwave dielectric properties of these materials were studied for the first time. SrRE4Si3O13 ceramics have a low relative permittivity (,r) in the range 9,16, a Q-factor (Qu×f) upto 26 000 GHz and a low temperature coefficient of resonant frequency (,f). The SrLa4Si3O13 ceramics possessed a high Qu×f of nearly 26 000 GHz but with a high negative ,f of ,46 ppm/°C. The ,f of SrLa4Si3O13 ceramics was tuned by the addition of suitable amount of TiO2. [source] Conversion of Tetranary Borate Glasses to Phosphate Compounds in Aqueous Phosphate SolutionJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2008Wenhai Huang In our earlier work, it was found that particles of a ternary alkali-borate glass, containing either CaO or BaO, converted completely to a crystalline phosphate of calcium or barium when reacted in an aqueous phosphate solution at 37°C. The present work is an extension of our earlier work to investigate the conversion of tetranary borate glass with the composition 10Li2O·10CaO·10(AeO or T2O3)·60B2O3 (weight percent), where Ae is the alkai-earth metal Mg or Ba, and T is the transition metal La, Sm, or Dy. In the experiments, particles of each glass (150,300 ,m) were reacted in 0.25M K2HPO4 solution with a starting pH of ,9.0 at 37°C. Weight loss and pH measurements indicated that the reaction was complete after 30,50 h, yielding an amorphous product. X-ray fluorescence showed that the as-formed product consisted of a calcium phosphate phase that contained the alkali-earth metal or transition metal present in the starting glass. Heating the as-formed material for 8 h at 600°,700°C produced a mixture of two crystalline phosphates: calcium phosphate and an alkali-earth or transition metal phosphate. The kinetics and mechanism of converting tetranary borate glass to phosphate materials are discussed and compared with data from earlier work for the conversion of ternary borate glass. [source] Metastable Phase Formation from an Undercooled Rare-Earth Orthoferrite MeltJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2002Kosuke Nagashio High-speed digital imaging was conducted during the containerless solidification of rare-earth orthoferrites (RE = La, Sm, Dy, Y, Yb, and Lu) with the perovskite structure to determine the metastable phase and elucidate its growth behavior. Observation using a high-speed video camera revealed that the formation of the metastable phase became pronounced, and double recalescence from the metastable phase to a stable phase occurred, as the ionic radius of the rare-earth element decreased. In the present paper, the formation of the metastable phase is discussed systematically in view of the stability of the perovskite structure and the activation energy of nucleation. [source] Preparation, Characterization, and Microwave Properties of RETiNbO6 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, and Yb) Dielectric CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2001Mailadil T. Sebastian Microwave ceramic dielectric resonators (DRs) based on RETiNbO6 (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Y, and Yb) have been prepared using the conventional solid-state ceramic route. The DR samples are characterized using XRD and SEM methods. The microwave dielectric properties are measured using resonant methods and a net work analyzer. The ceramics based on Ce, Pr, Nd, and Sm have dielectric constants in the range 32,54 and positive coefficient of thermal variation of resonant frequency (,f). The ceramics based on Gd, Tb, Dy, Y, and Yb have dielectric constants in the range 19,22 and negative ,f. [source] Effects of M3+ Ions on the Conductivity of Glasses and Glass-Ceramics in the System Li2O,M2O3,GeO2,P2O5 (M = Al, Ga, Y, Dy, Gd, and La)JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2000Jie Fu Glasses with compositions Li1.2M0.2Ge1.8(PO4)3 (M = Al, Ga, Y, Gd, Dy, and La) were prepared and converted to glass-ceramics by heat treatment. The effects of the M3+ ions on the conductivity of the glasses and glass-ceramics were studied. The main phase present in the glass-ceramics was the conductive phase LiGe2(PO4)3. Al3+ and Ga3+ ions entered the LiGe2(PO4)3 structure by replacing Ge4+ ions, but lanthanide ions did not. The glass-ceramics exhibited much higher conductivity than the glasses. With increased ionic radius of the M3+ ions, the conductivity remained almost unchanged at ,3 × 10,12 S/cm for the glasses, but it decreased from 1.5 × 10,5 to 8 × 10,9 S/cm for the glass-ceramics at room temperature. The higher conductivity for Al3+ - and Ga3+ -containing glass-ceramics was suggested to result from the substitutions of Al3+ and Ga3+ ions for Ge4+ ions in the LiGe2(PO4)3 structure. [source] | ||||||||||||||||||||||