bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel carbazole dendrimers having a metal coordination site as a unique hole‐transport material
Authors: Kimoto Atsushi , Cho Jun‐Sang , Higuchi Masayoshi , Yamamoto Kimihisa 
Published: April 2004

AbstractWe have synthesized novel carbazole dendrimers via the cyclotrimerization of aminophenylketones in the presence of titanium tetrachloride. These dendrimers have the ability to assemble metal ions such as Sn2+ and Eu3+ with no significant difference in their generation, suggesting the dendrimer with an interior with a small density up to the third generation. We show the dendrimers with higher generations have the higher HOMO values. The most electron rich molecule, the G3 dendrimer, has the highest HOMO value of −5.2 eV. However, for the HOMO energy levels of the carbazole dendrimer complex with Eu(OTf)3, the energy levels of the carbazoles did not change based on almost the same redox potentials as those of the dendrimers, themselves. Using the carbazole dendrimers and their europium complex, a homogeneous film was produced, which enhanced the performance of the electroluminescence device in comparison with only the dendrimer as the hole‐transporting layer. This approach was managed by a solution process, i.e., the spin‐coating method, without using the coevaporation technique based on the large equilibrium constants of the coordination of metal ions on the imine sites (K = 105 M−1).
Luminescence properties of organometallic/coordination oligomers and polymers containing diphosphine and diisocyanide assembling ligands: comparison between mononuclear model complexes and polymers
Authors: Harvey Pierre D. 
Published: April 2004

AbstractThis paper describes the luminescence properties of selected examples of homo‐ and mixed‐bridging ligand‐containing organometallic/coordination oligomers and polymers of copper(I), silver(I), palladium(I) and −(0.5), and platinum(0.5). The bridging ligands are the 1,8‐diisocyano‐p‐menthane (dmb) and bis(diphenylphosphino)methane (dppm), ‐ethane (dppe), ‐propane (dppp), ‐butane (dppb), ‐pentane (dpppen), and −hexane (dpph), as well as bis(diphenyl‐phosphino)acetylene (dpa) and bis(dimethylphosphino)methane (dmpm). The comparison between the mononuclear model complexes and the polymers of the emission maxima (λmax) and emission lifetimes (τe) will be made, and interpreted by the presence of intrachain interactions and exciton phenomena.
Metallodendritic materials for heterogenized homogeneous catalysis
Authors: Bourrier Olivier , Kakkar Ashok K. 
Published: April 2004

AbstractDesign of supports containing a hyperbranched backbone and active transition metal centers at the periphery is described. Such nanoarchitectures can be easily assembled from 3,5‐dihydroxybenzyl alcohol and dimethylsilylamine using a divergent synthetic methodology. Following a controlled reaction pathway, construction of dendrimers of up to generation 5 is achieved, while a simple mix of reagents in one‐pot or with sequential additions yields analogous hyperbranched polymers. Subsequent functionalization at the periphery with phosphine followed by Rh(I) centers yields the desired metallodendritic materials. The efficiency of the latter in catalytic hydrogenation of decene under varied conditions is surveyed.
Ring‐opening polymerisation of coordination rings and cages
Authors: James Stuart L. 
Published: April 2004

AbstractDespite the great interest in crystalline coordination polymers (sometimes called metal organic frameworks) surprisingly little is known about how they form. However, there has recently been some attention given to characterising their solution‐based precursors. Of particular interest is the formal ring‐opening polymerisation (ROP) relationship between the structures of some precursors and polymers, and the actual observation of ring‐opened oligomers by solution state NMR spectroscopy. These points are highlighted and discussed along with related aspects of isomerism in discrete and polymeric coordination structures, and polymer‐polymer interconversion.
Synthesis of sulfone‐containing monomers and polymers using cationic cyclopentadienyliron complexes
Authors: Abd‐El‐Aziz Alaa S. , Pereira Nelson M. , Boraie Waleed , McFarlane Shaune L. , Todd Erin K. 
Published: April 2004

AbstractThe synthesis of sulfone‐containing monomers with pendent cationic cyclopentadienyliron (CpFe+) moieties has been accomplished via nucleophilic aromatic substitution of dichloroarene complexes with a number aliphatic dithiols. These complexes were further oxidized using m‐CPBA to give the sulfone‐based monomers. Polymerization of the sulfone‐based monomers with O‐containing nucleophiles produced the sulfone‐based polymers. Direct nucleophilic aromatic substitution of dichloroarene complexes with dinucleophiles allowed for the formation of organoiron sulfide‐based polymers. Oxidation of these polymers led to the formation of sulfone polymers with the pendent iron moieties. The organometallic monomers and polymers were found to be more soluble in polar solvents in comparison to their organic analogues.
Investigation of spatial inhomogeneities of the thermal properties of a NiTi shape memory alloy device
Authors: Gibkes J. , Siegert W. , Bein B.K. , Pelzl J. 
Published: April 2004

AbstractLocal changes of the phase transition on a SM one‐way actuator have been investigated by time‐dependent IR thermography and compared with the local behavior of thermal properties studied by means of scanning thermal microscopy and modulated IR radiometry at room temperature and at 120 °C. The results point towards large spatial inhomogeneities of the shape memory properties developing with increasing temperature and which are the reason that only parts of the material transform into the austenite phase.
High‐Temperature Corrosion of NiTi‐Shape‐Memory Alloys
Authors: Heßing C. , Gabert S. , Pohl M. , Parezanović I. 
Published: April 2004

AbstractSemi‐finished products and components made of NiTi‐shape‐memory alloys (NiTi‐SMA) are often subjected to heat treatment after their fabrication. During this heat treatment, oxide layers begin to form which contain a high amount of titanium.In this investigation special attention was drawn to the selective oxidation of Ti because a TiOX‐layer can represent a Ni‐barrier and may therefore be of special use for medical applications. A comparison of the following three samples was carried out: A sample oxidised at room temperature, another that was heat‐treated in ambient air (600 °C/1min) and a third sample that was subjected to a heat treatment (600 °C/1min) in an atmosphere that oxidises titanium but reduces NiO in order to achieve a selective oxidation of the titanium. The analysis of the oxide layers was carried out by means of x‐ray photoelectron spectroscopy (XPS). It was shown that the ratio of titanium to nickel in the oxide layer can be substantially increased when performing the annealing treatments in a partial reducing atmosphere.Furthermore, a thermo‐gravimetric investigation of the material was carried out at 600 °C in dry air in order to estimate the growth of the oxide layers.
Alternating current scanning electrochemical microscopy (AC‐SECM) studies on the surface of electrochemically polished NiTi shape memory alloys
Authors: Belger S. , Schulte A. , Hessing C. , Pohl M. , Schuhmann W. 
Published: April 2004

AbstractAiming at imaging local differences in electrochemical activity and related corrosion effects, the surface of electropolished NiTi was investigated using alternating current scanning electrochemical microscopy (AC‐SECM). Segregation‐related spatial variations in the rates of the anodic dissolution that are responsible for the formation of wavy surfaces during electropolishing could not be identified with AC‐SECM. Instead, the surface appeared rather uniform and did not reflect any (patterned) corrosion activity. Obviously, the anodically grown oxide film is highly isolating and passivating. This rationalizes the absence of the evolution of surface irregularities at the solid/liquid interface of NiTi‐shape‐memory alloys.
Porous Metal Sheets of NiTi made by Wet Powder Spraying
Authors: Schüller E. , Krone L. , Bram M. , Buchkremer H. P. , Stöver D. 
Published: April 2004

AbstractAs a promising method to produce thin porous NiTi sheets, Wet Powder Spraying (WPS) is applied for NiTi powders. Layers with a thickness of 150 μm are obtained from pre‐alloyed NiTi powders with a particle size of < 12 μm. Optimized process control for spraying and sintering was used. Microstructure and phase formation is characterized. The sheets with a porosity of 15 % show a high pseudoelastic flexibility at room temperature. Phase transformation temperatures are determined by Differential scanning calorimetry (DSC). The one way effect could be demonstrated.
NiTi shape memory alloys coated with calcium phosphate by plasma‐spraying. Chemical and biological properties
Authors: Prymak O. , Bogdansk D. , Esenwein S.A. , Köller M. , Epple M. 
Published: April 2004

AbstractPlates of superelastic nickel‐titanium shape memory alloy (NiTi) were coated with calcium phosphate (hydroxyapatite) by high‐temperature plasma‐spraying. The porous layer of about 100 μm thickness showed a good adhesion to the metallic substrate that withstood bending of the plate but detached upon cutting the plate. The biocompatibility was tested by cultivation of blood cells (whole blood and isolated granulocytes [a subpopulation of blood leukocytes]). As substrates, pure NiTi, plasma‐spray‐coated NiTi and calcium phosphate‐coated NiTi prepared by a dip‐coating process were used. The adhesion of whole blood cells to all materials was not significantly different. In contrast, isolated granulocytes showed an increased adhesion to both calcium phosphate‐coated NiTi samples. However, compared to non‐coated NiTi or dip‐coated NiTi, the number of dead granulocytes adherent to plasma‐sprayed surfaces was significantly increased for isolated granulocytes (p<0.01).
Numerical Modelling of the Activation Behaviour of SMA‐Actuator Wires – Application in an Innovative Drive System
Authors: Meier H. , Oelschläger L. 
Published: April 2004

AbstractThe activation behaviour of Shape‐Memory‐Alloy actuators (SMA) (and more specifically their dynamic properties) is characterised by the rate of heating and cooling. This paper deals with the development, the validation and the application of a numerical model that simulates the activation behaviour of straight SMA‐wires depending on their geometry, the loading condition and an arbitrary time variant heating current. Taking changing thermal, electrical, geometric and mechanical boundary conditions into consideration, the model supports the design layout process of technical solutions with SMA‐wires. Based on this numerical model for dimensioning and conditioning of SMA‐actuators, an innovative rotatory drive system powered by straight SMA‐wires is presented.
A new finite element technology for shape memory alloy composites
Authors: Christ D. , Reese S. , Neuking K. 
Published: April 2004

AbstractIn this paper, we present a computationally efficient implementation of a continuum mechanical model for shape memory alloys into a finite element code. The model covers several thermomechanically coupled effects typical for the material behaviour of shape memory alloys, e.g. pseudo‐elasticity, the one‐way shape memory effect and the two‐way shape memory effect due to external loads. Via the use of a finite element formulation based on only one Gauss point, the computational effort is reduced enormously.
Double‐blind, randomized, controlled trial of rasagiline as monotherapy in early Parkinson's disease patients
Authors: Stern Matthew B. , Marek Kenneth L. , Friedman Joseph , Hauser Robert A. , LeWitt Peter A. , Tarsy Daniel , Olanow C. Warren 
Published: April 2004

AbstractRasagiline (N‐propargyl‐1(R)‐aminoindan) mesylate is a potent, selective, and irreversible monoamine oxidase‐B inhibitor. This study was designed to evaluate the safety, tolerability, and preliminary efficacy of rasagiline monotherapy in early Parkinson's disease (PD) patients not receiving levodopa. The study was performed as a multicenter, parallel‐group, double‐blind, randomized, placebo‐controlled, 10‐week study. Fifty‐six PD patients were randomly assigned to rasagiline mesylate 1, 2, or 4 mg once daily, or placebo. A 3‐week dose‐escalation period was followed by a 7‐week maintenance phase. At week 10, the mean (±SE) changes from baseline in total Unified Parkinson's Disease Rating Scale (UPDRS) score were −1.8 (±1.3), −3.6 (±1.7), −3.6 (±1.2), and −0.5 (±0.8) in the rasagiline 1, 2, and 4 mg/day and placebo groups, respectively. Analysis of responders showed that 28% of patients (12 of 43) receiving rasagiline had an improvement in total UPDRS score of greater than 30%, compared with none of the patients receiving placebo (P < 0.05, Fisher's exact test). The frequency and types of adverse events reported by rasagiline‐treated and placebo‐treated patients were similar. These results suggest that rasagiline monotherapy is well tolerated and efficacious in early PD. © 2004 Movement Disorder Society
A note on a secure voting system on a public network
Authors: Karagiannopoulos M. G. , Vrahatis M. N. , Meletiou G. C. 
Published: April 2004

AbstractThis article shows that the procedure proposed in Chang and Wu (1997) and extended in Dini (2001) does not always produce accurate results. A modification that makes the procedure correct is suggested. © 2004 Wiley Periodicals, Inc.
Stress‐ and cell cycle‐associated regulation of RGS2 mRNA levels
Authors: Zmijewski Jaroslaw W. , Song Ling , Jope Richard S. 
Published: April 2004

AbstractRegulators of G‐protein signaling family members, such as RGS2, are thought to primarily be involved in regulating the activity of second messenger systems by attenuating heterotrimeric G‐protein actions. However, we found previously that RGS2 is predominantly located in the nucleus, not at the plasma membrane where most G‐proteins exist, and that stressful conditions increased RGS2 expression. Here we report that induction of DNA damage‐induced cell cycle arrest with camptothecin caused prolonged increases in RGS2, and decreases in RGS4, mRNA levels. Cell cycle arrest caused by nocodazole also increased RGS2, and decreased RGS4, mRNA levels. Additionally, using synchronization to minimize cell stress, RGS2 mRNA levels were low in G0 and G1, and elevated in the other phases of the cell cycle. These results demonstrate that RGS2 expression is coupled to cellular stress and the cell cycle, and that these conditions cause opposite effects on RGS2 and RGS4 mRNA levels.
Treadmill exercise suppresses NPY expression in the hypothalamus of food‐deprived rats
Authors: Kim Sung‐Soo , Shin Mal‐Soon , Kim Hong , Kim Eun‐Kyung , Lee Hee‐Hyuk , Chang Hyun‐Kyung , Lee Taeck‐Hyun , Jang Mi‐Hyeon , Shin Min‐Chul , Lim Baek‐Vin , Kim Chang‐Ju 
Published: April 2004

AbstractExercise has been known to potentially affect food intake. Neuropeptide Y (NPY) is a 36 amino acid peptide and concentrated in the hypothalamus which is an appetite‐regulating area. NPY is known to stimulate appetite and decrease energy expenditure. In the present study, the effect of treadmill running on the NPY expression in the hypothalamus of food‐deprived rats was investigated using immunohistochemistry. Enhanced NPY expression in the paraventricular nucleus (PVN) and arcuate nucleus (ARN) was observed in the food‐deprived rats. Treadmill exercise suppressed the enhancement of NPY expression in the PVN and ARN following food deprivation, but this suppressive effect was not affected by exercise intensity. Based on the present results, it can be suggested that treadmill exercise is effective in limiting the enhancement of NPY expression following food‐deprived conditions.
JC virus genotyping offers a new paradigm in the study of human populations
Authors: Yogo Yoshiaki , Sugimoto Chie , Zheng Huai‐Ying , Ikegaya Hiroshi , Takasaka Tomokazu , Kitamura Tadaichi 
Published: April 2004

AbstractA small DNA virus, named JC virus (JCV) and belonging to the Polyomaviridae, is attracting the attention of anthropologists worldwide, as JCV genotyping appears to be a novel means of elucidating human migrations and the origins of various ethnic groups. The basic properties of JCV, the regional distributions of JCV genotypes, and the phylogenetic relationships among various JCV genotypes are described. Then, a study is described in which the origin of the modern Japanese was extensively investigated using the JCV genotyping method. Based on JCV genotypes in neighboring areas, the origins of people who carried JCV genotypes to the Japanese Archipelago are discussed. Finally, the relationships between JCV genotypes and Y‐chromosome haplogroups are examined, as genetic variation on the Y chromosome has recently been examined in detail to investigate ancient human migrations and the population structures of human groups. Copyright © 2004 John Wiley & Sons, Ltd.
Combining several ordinal measures in clinical studies
Authors: Wittkowski Knut M. , Lee Edmund , Nussbaum Rachel , Chamian Francesca N. , Krueger James G. 
Published: April 2004

AbstractIn medical research, it is rare that a single variable is sufficient to represent all relevant aspects of epidemiological risk, genomic activity, adverse events, or clinical response. Since biological systems tend to be neither linear, nor hierarchical in nature, the assumptions of traditional multivariate statistical methods based on the linear model can often not be justified on theoretical grounds. Establishing concept validity through empirical validation is not only problematic, but also time consuming. This paper proposes the use of u‐statistics for scoring multivariate ordinal data and a family of simple non‐parametric tests for analysis. The scoring method is demonstrated to be applicable to scoring clinical response profiles in the treatment of psoriasis and then to identifying genomic pathways that best correlate with these profiles. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and Characterization of Cross‐linked Carboxymethyl Potato Starch Ether Gels
Authors: Seidel Christian , Kulicke Werner‐Michael , Heß Christoph , Hartmann Brigitte , Lechner M. Dieter , Lazik Waldemar 
Published: April 2004

AbstractHydrogels were synthesized by cross‐linking of potato starch (PS) with dichloroacetic acid (DCA) in the presence of monochloroacetic acid (MCA) to form etherified carboxymethyl starch (CMS) gels, to be used for ultrasonic medical examinations. By etherification cross‐linked CMS‐hydrogels can be produced, that are stable in contrast to the in the long‐term unstable esterified gels, that were presented in the last paper. The rheological benchmarks for the CMS‐hydrogels were set in comparison with synthetic ultrasonic gels. Gels with potato starch contents in the reaction batch ranging from 12.5% to 20% showed the best compliance with the benchmark parameters. The DS values of these CMS‐hydrogels vary from 0.42 to 0.49, increasing with decreasing amount of starch in the reaction mixture. The free swelling capacities (FSC) vary between 77 g/g for the 12.5% PS‐gel and 34 g/g for 20% PS‐gel, the turbidities of the samples being in the range from 14.5 NTU (Nephelometric Turbidity Units) (12.5% PS) up to 20.5 NTU (20% PS). The variation of the PS fraction in the reaction mixture showed that with an increased amount of PS in the reaction batch the number of cross‐links of the CMS‐gels increases, too. At a higher number of cross‐links the swelling capacity is reduced and the concentration needed to form stable hydrogels is greatly increased. Thus a hydrogel of a polymer concentration of 5 mass‐% from a 12.5% PS batch was produced, that showed the best accordance with the rheological benchmark parameters such as gelatinization time, visco‐elastic and pseudoplastic properties and long‐term stability. The ultrasonic pictures taken with this CMS‐gel were not different from those taken with the synthetic gels. This hydrogel was then subjected to long‐term‐stability measurements performed over one year and to rheological temperature cycle tests. The tests showed that the long‐term stability of the gels is sufficient for their use as ultrasonic gel.
Lintnerization of Two Amylose‐free Starches of A‐ and B‐Crystalline Types, Respectively
Authors: Bertoft Eric 
Published: April 2004

AbstractWaxy maize starch (WMS) and potato amylopectin starch (PAPS), representing amylose‐free A‐ and B‐crystalline granules, respectively, were subjected to hydrolysis in diluted hydrochloric acid (lintnerization). The solubilization rate of the granules was dependent on the temperature, but there were only small differences between the samples. The compositions of the lintners obtained at 29°C were also similar, though the sensitivity to enzymatic debranching was different. The degree of debranching increased significantly if pullulanase and isoamylase were used successively. Because some branches remained resistant to enzymatic attack, the degree of scattered branching was difficult to estimate. The amount and composition of β‐limit dextrins suggested, however, that both starches contained scattered branches. Long chains and the shortest chains in the amylopectin molecules were sensitive to lintnerization and therefore probably located outside the crystallites. The composition of the PAPS lintners was dependent on the temperature of the lintnerization, whereas that of WMS lintners was not. The composition of a lintner from normal potato starch was compared with PAPS, and it is concluded that the presence of amylose has a higher effect than the type of crystallinity on the lintnerization results.
Midcareer and senior faculty learning communities: Learning throughout faculty careers
Authors: Blaisdell Muriel L. , Cox Milton D. 
Published: April 2004

AbstractFaculty members' productivity may shift over time, not as a function of age but as a function of the amount of time a senior faculty member spends with colleagues (Bland and Bergquist, 1997). This chapter shows
how faculty learning communities can provide the opportunities and connections that senior and midcareer faculty need to continue productive academic lives.
On well‐posedness and conditioning in optimization
Authors: Zolezzi T. 
Published: April 2004

AbstractWe survey some results dealing with well‐posedness of scalar optimization problems, with applications to the optimal control of ordinary differential equations under plant perturbations. Then we deal with the definition of a condition number for optimization problems. Corresponding distance theorems are discussed, aiming to generalize the Eckart‐Young theorem to the infinite‐dimensional setting.