bluuebunny/crossref_metadata_2025 huggingface dataset:
Essential oil composition of Hypericum hirsutum L.
Authors: Gudžic B. T. , Šmelcerović A. , D̄ord̄ević S. , Mimica‐Dukić N. , Ristić M.
Published: September 2006

The essential oil of Hypericum hirsutum was analysed for the first time. Twenty‐seven components were identified. The non‐terpene compounds had the highest contribution (46.6%). A low monoterpenes content (1.3%) characterized the oil. The major constituents were n‐undecane (32.2%), patchoulene (11.8%) and caryophyllene oxide (9.3%), which are not significantly represented in the essential oils of other species of the genus Hypericum examined. Copyright © 2006 John Wiley & Sons, Ltd.
The admixture maximum likelihood test: a novel experiment‐wise test of association between disease and multiple SNPs
Authors: Tyrer Jonathan , Pharoah Paul D.P. , Easton Douglas F.
Published: September 2006

Disease association studies often test large numbers of markers, and various methods have been proposed to correct for multiple testing. In this paper, we propose an admixture maximum likelihood approach that estimates both the proportion of associated single nucleotide polymorphisms (SNPs) and their typical effect size. We assessed this method and compared it with several previously proposed approaches by simulation. The maximum likelihood approach performed similarly to or better than all other tests across a wide range of alternative hypotheses. The rank truncated product method also had good power, though somewhat inferior to the maximum likelihood approach in most cases. A simple Bonferroni correction performed best only when the number of associated SNPs was small.Genet.Epidemiol. 2006. © 2006 Wiley‐Liss, Inc.
Microglia instruct subventricular zone neurogenesis
Authors: Walton Noah M. , Sutter Benjamin M. , Laywell Eric D. , Levkoff Lindsay H. , Kearns Sean M. , Marshall Gregory P. , Scheffler Bjorn , Steindler Dennis A.
Published: September 2006

Microglia are increasingly implicated as a source of non‐neural regulation of postnatal neurogenesis and neuronal development. To evaluate better the contributions of microglia to neural stem cells (NSCs) of the subventricular neuraxis, we employed an adherent culture system that models the continuing proliferation and differentiation of the dissociated neuropoietic subventricular tissues. In this model, neuropoietic cells retain the ability to self‐renew and form multipotent neurospheres, but progressively lose the ability to generate committed neuroblasts with continued culture. Neurogenesis in highly expanded NSCs can be rescued by coculture with microglial cells or microglia‐conditioned medium, indicating that microglia provide secreted factor(s) essential for neurogenesis, but not NSC maintenance, self‐renewal, or propagation. Our findings suggest an instructive role for microglial cells in contributing to postnatal neurogenesis in the largest neurogenic niche of the mammalian brain. © 2006 Wiley‐Liss, Inc.
Phenotypic and functional characteristics of mesenchymal stem cells differentiated along a Schwann cell lineage
Authors: Caddick Jenny , Kingham Paul J. , Gardiner Natalie J , Wiberg Mikael , Terenghi Giorgio
Published: September 2006

We have investigated the phenotypic and bioassay characteristics of bone marrow mesenchymal stromal cells (MSCs) differentiated along a Schwann cell lineage using glial growth factor. Expression of the Schwann cell markers S100, P75, and GFAP was determined by immunocytochemical staining and Western blotting. The levels of the stem cell markers Stro‐1 and alkaline phosphatase and the neural progenitor marker nestin were also examined throughout the differentiation process. The phenotypic properties of cells differentiated at different passages were also compared. In addition to a phenotypic characterization, the functional ability of differentiated MSCs has been investigated employing a co‐culture bioassay with dissociated primary sensory neurons. Following differentiation, MSCs underwent morphological changes similar to those of cultured Schwann cells and stained positively for all three Schwann cell markers. Quantitative Western blot analysis showed that the levels of S100 and P75 protein were significantly elevated upon differentiation. Differentiated MSCs were also found to enhance neurite outgrowth in co‐culture with sensory neurons to a level equivalent or superior to that produced by Schwann cells. These findings support the assertion that MSCs can be differentiated into cells that are Schwann cell‐like in terms of both phenotype and function. © 2006 Wiley‐Liss, Inc.
On the winter evolution of snow thermophysical properties over land‐fast first‐year sea ice
Authors: Langlois Alexandre , Mundy C. J. , Barber David G.
Published: September 2006

The geophysical, thermodynamic and dielectric properties of snow are important state variables that are known to be sensitive to Arctic climate variability and change. Given recent observations of changes in the Arctic physical system (Arctic Climate Impact Assessment, 2004), it is important to focus on the processes that give rise to variability in the horizontal, vertical and temporal dimensions of the life‐history of snow on sea ice. The objectives in this study are to present these ‘state’ variables and to investigate the processes that govern variability in the vertical, horizontal and temporal dimension by using a case study over land‐fast first‐year sea ice for the period December 2003 to June 2004.

Results from two sampling areas (thin and thick snowpacks) show that differences in snowpack thickness can substantially change the vertical and temporal evolution of snow properties. During the late fall and early winter (cooling period) we measured no significant changes in the physical properties, except for thin snow‐cover salinity, which decreased throughout the period. Fall‐snow desalination was only observed under thin snowpacks with a rate of −0·12 ppt day−1. Significant changes occurred in the late winter and early spring (warming period), especially for snow grain size. Snow grain kinetic growth of 0·25–0·48 mm·day−1 was measured coincidently with increasing salinity and wetness for both thin and thick snowpacks. Copyright © 2006 John Wiley & Sons, Ltd.
Development and validation of a reversed‐phase HPLC method for monitoring of synthetic reactions during the manufacture of a key intermediate of an anti‐hypertensive drug
Authors: Rao Ramisetti Nageswara , Nagaraju Dongari , Jena Nivedita , Kumaraswamy Gullapalli
Published: September 2006

A reversed‐phase high‐performance liquid‐chromatographic method for monitoring of reactions involved in process development of a key intermediate of antihypertensive drugs, e.g, doxazosin mesylate, prazosin, alfuzosin, terazosin, etc., has been developed and validated. The HPLC profiles of impurities of 4‐amino‐2‐chloro‐6,7‐dimethoxyquinazoline were used as fingerprints to follow the synthetic procedures in the manufacturing unit. The separation was accomplished on an Inertsil ODS‐3 column with isocratic elution using acetonitrile‐ammonium acetate (10 mM; pH 4.0; 50:50 v/v) as mobile phase and a photodiode array detector set at 240 nm at ambient temperature. The method was validated with respect to accuracy, precision, linearity, and limits of detection and quantification. The method could detect the impurities at a level of 0.01 to 0.20 μg/mL and it was found to be suitable not only for monitoring of reactions but also for quality assurance of 4‐amino‐2‐chloro‐6,7‐dimethoxyquinazoline.
Controlling laser assisted radiative recombination with few-cycle laser pulses
Authors: Bivona S , Burlon R , Leone C
Published: September 2006

We report on the radiative recombination of a free electron with a hydrogenic ion in the presence of a few-cycle pulses. It has been shown that the main features of the emission spectra may be described in the framework of a semiclassical model in which the recombination is viewed as a two-step process. The spectra width of the emitted photon energy is practically confined in a range of values in which the emission is classically allowed. Moreover, it has been found that spectra width can be controlled by varying the carrier envelope phase and/or the pulse peak intensity.
Appearance of coherent artifact signals in femtosecond
transient absorption spectroscopy in dependence on detector design
Authors: Dietzek B , Pascher T , Sundström V , Yartsev A
Published: September 2006

The appearance of coherent artifact signals in transient
absorption spectroscopy employing a spectrally integrated
detection system is studied. The influence of the detection design
on the shape of the observed signal is detailed and the
experimentally very important case, in which the shape of the
coherent artifact is strongly influenced by the presence of the
sample itself, is considered – leading to the situation that the
artifact signal cannot be accounted for by simple comparison of
the kinetics obtained for the solvent only. Finally, an estimate
of the relative contribution of the artifact to the overall
transient absorption changes is presented facilitating the
interpretation of short time transients in the presence of
artifact contributions and allowing to estimate the excited state
absorption cross-section for a known pump-intensity dependence of
the artifact signal.
Alzheimer's disease presenting as corticobasal syndrome
Authors: Chand Pratap , Grafman Jordan , Dickson Dennis , Ishizawa Keisuke , Litvan Irene
Published: September 2006

A 60‐year‐old man presented with slowly progressive left hemi‐Parkinsonism, left hand apraxia, myoclonus, dystonia, visuospatial disturbances, and alien limb phenomenon, resembling corticobasal syndrome. Eight years later, neuropathology revealed features of Alzheimer's disease, with asymmetrical (right more than left) cortical tau burden with image analysis. The videotaped clinical features, neuropsychological aspects, and neuropathological correlates are presented and discussed. © 2006 Movement Disorder Society
Density functional computations of 99Ru chemical shifts: relativistic effects, influence of the density functional, and study of solvent effects on fac—[Ru(CO)3I3]−
Authors: Autschbach Jochen , Zheng Shaohui
Published: September 2006

Solvent effects on the 99Ru NMR chemical shift of the complex fac—[Ru(CO)3I3]− are investigated computationally using density functional theory. Further, benchmark calculations of the 99Ru shift for a set of ten Ru complexes have been performed in order to calibrate the computational model and to determine the importance of relativistic effects on the 99Ru nuclear magnetic shielding and on the chemical shift. A computational model for fac—[Ru(CO)3I3]− that includes both explicit solvent molecules and a continuum model is shown to yield the best agreement with experiment. Relativistic corrections are shown to be of minor importance for determining 99Ru chemical shifts. On the other hand, the nature of the density functional is of importance. In agreement with literature data for ligand trends of 99Ru chemical shifts, the chemical shift range for different solvents is also best reproduced by a hybrid functional. Copyright © 2006 John Wiley & Sons, Ltd.
Direct NMR resonance assignments of the active site histidine residue in Escherichia coli thioesterase I/protease I/lysophospholipase L1
Authors: Wu Wen‐Jin , Tyukhtenko Sergiy I. , Huang Tai‐Huang
Published: September 2006

Owing to the hydrogen‐bond interaction and rapid exchange rate with the bulk water, the transverse relaxation time for the Nδ1H proton of the catalytic histidine in Escherichia coli thioesterase I/protease I/lysophospholipase L1 (TEP‐I) is rather short. Because of its catalytic importance, it is desirable to detect and assign this proton resonance. In this paper, we report the first direct NMR correlation between the short‐lived Nδ1H proton and its covalently attached Nδ1–nitrogen of the catalytic His157 residue in E. coli thioesterase/protease I. We have used gradient‐enhanced jump‐return spin‐echo HMQC (GE‐JR SE HMQC) to obtain a direct correlation between the short‐lived Nδ1H proton and its covalently attached Nδ1–nitrogen. The sensitivity of detection for the short‐lived Nδ1H proton was enhanced substantially by improved water suppression, in particular, the suppression of radiation damping via pulsed field gradients. Copyright © 2006 John Wiley & Sons, Ltd.
Malabsorption syndrome with and without small intestinal bacterial overgrowth: A study on upper‐gut aspirate using 1H NMR spectroscopy
Authors: Bala Lakshmi , Ghoshal Uday Chand , Ghoshal Ujjala , Tripathi Pratima , Misra Asha , Gowda G.A. Nagana , Khetrapal C.L.
Published: September 2006

Biochemicals in the upper‐gut aspirate in 31 patients with malabsorption syndrome (MAS) with and without small intestinal bacterial overgrowth (SIBO), and 10 disease‐free controls were analyzed using high‐resolution 1H‐NMR spectroscopy, and were correlated with the degree of SIBO and severity of MAS. Compared to controls, the patients had higher quantities (μmol/L: median [range]) of total bile acids/cholesterol (2000 [0–12000] vs. 300 [0–600]), lactate (700 [0–5200] vs. nil [0–30]), acetate (200 [0–6500] vs. 20 [0–200]), and formate (80 [0–900] vs. nil [0–50]) (P < 0.01, Mann‐Whitney U‐test). However, amino acids and glucose were comparable in both. Quantities (μmol/L: median [range]) of acetate (1330 [220–6500] vs. 100 [0–1430]), lactate (1430 [670–3300] vs. 300 [0–5200]), formate (360 [0–600] vs. 25 [0–800]), and unconjugated bile acids (500 [40–600] vs. 10 [0–300]) were higher in MAS patients with SIBO than those without SIBO (P < 0.01, Mann‐Whitney U‐test, for all). In patients with MAS the quantity of acetate positively correlated with the degree of SIBO, and unconjugated bile acids correlated with the degree of steatorrhoea (Spearman's rank correlation coefficient, two‐tailed, P < 0.05: 0.46 and 0.52, respectively). This study demonstrates the bacterial production of metabolites and deconjugation of bile acids in patients with MAS. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Improvement of reduction method combined with sub‐domain scheme in large‐scale problem
Authors: Kim Hyungi , Cho Maenghyo
Published: September 2006

For a few decades, various approximate techniques have been developed to calculate the eigenvalues in a reduced manner. In order to construct reliable reduced systems it is essential to select the proper primary degrees of freedom (PDOFs). Unless the PDOFs are selected properly, the selection of PDOFs might be localized and the eigenvalue prediction might emphasize excessively the lower modes or lose the important modes. Moreover, sometimes, it takes considerable amount of computing time to construct a reduced system in large‐scale problem. These troubles in constructing reduced system can be avoided by applying reduction scheme in sub‐domain level. After dividing global system into a number of sub‐domains, reduced system which has only the PDOFs is constructed in each sub‐domain. This paper presents new algorithms to construct efficient reduction system through three different schemes. They are version 1, version 2 and version 3 systems. The version 3 system is constructed by combining the advantages of the version 1 and the version 2 systems. Numerical examples demonstrate that the proposed version 3 method saves computational cost effectively and provides a reduced system which can predict accurate eigenvalues of global system. Copyright © 2006 John Wiley & Sons, Ltd.
Advances in plant proteomics
Authors: Chen Sixue , Harmon Alice C.
Published: September 2006

With the avalanche of genomic information and improvements in analytical technology, proteomics is becoming increasingly important for the study of many different aspects of plant functions. Since proteins serve as important components of major signaling and biochemical pathways, studies at protein levels are essential to reveal molecular mechanisms underlying plant growth, development, and interactions with the environment. The plant proteome is highly complex and dynamic. Although great strides need to be taken towards the ultimate goal of characterizing all the proteins in a proteome, current technologies have provided immense opportunities for high‐throughput proteomic studies that have gone beyond simple protein identification to analyzing various functional aspects, such as quantification, PTM, subcellular localization, and protein–protein interactions. In this review of plant proteomics, advances in protein fractionation, separation, and MS will be outlined. Focus will be on recent development in functional analysis of plant proteins, which paves the way towards the comprehensive integration with transcriptomics, metabolomics, and other large scale “‐omics” into systems biology.
Proteomics and transfusion medicine: Future perspectives
Authors: Queloz Pierre‐Alain , Thadikkaran Lynne , Crettaz David , Rossier Joel S. , Barelli Stefano , Tissot Jean‐Daniel
Published: September 2006

Limited number of important discoveries have greatly contributed to the progresses achieved in the blood transfusion; ABO histo‐blood groups, citrate as anticoagulant, fractionation of plasma proteins, plastic bags and apheresis machines. Three major types of blood products are transfused to patients: red cell concentrates, platelet concentrates and fresh frozen plasma. Several parameters of these products change during storage process and they have been well studied over the years. However, several aspects have completely been ignored; in particular those related to peptide and protein changes. This review presents what has been done using proteomic tools and the potentials of proteomics for transfusion medicine.
Aqueous polymer two‐phase systems: Effective tools for plasma membrane proteomics
Authors: Schindler Jens , Nothwang Hans Gerd
Published: September 2006

Plasma membranes (PMs) are of particular importance for all living cells. They form a selectively permeable barrier to the environment. Many essential tasks of PMs are carried out by their proteinaceous components, including molecular transport, cell‐cell interactions, and signal transduction. Due to the key role of these proteins for cellular function, they take center‐stage in basic and applied research. A major problem towards in‐depth identification and characterization of PM proteins by modern proteomic approaches is their low abundance and immense heterogeneity in different cells. Highly selective and efficient purification protocols are hence essential to any PM proteome analysis. An effective tool for preparative isolation of PMs is partitioning in aqueous polymer two‐phase systems. In two‐phase systems, membranes are separated according to differences in surface properties rather than size and density. Despite their rare application to the fractionation of animal tissues and cells, they represent an attractive alternative to conventional fractionation protocols. Here, we review the principles of partitioning using aqueous polymer two‐phase systems and compare aqueous polymer two‐phase systems with other methods currently used for the isolation of PMs.
Proteomics as a route to identification of toxicity targets in environmental toxicology
Authors: Dowling Vera A. , Sheehan David
Published: September 2006

Ecotoxicology describes a three‐way relationship between ecosystems, chemical pollutants and living organisms. It is predicated on the fact that chemical pollution can exert toxic effects on organisms at the individual and population levels. These toxic effects may provide important information to supplement chemical analysis of environmental samples and aid in assessing the environmental quality of specific ecosystems. Traditionally, effects have been detected by means of biomarkers which, of necessity, were often molecules or processes known to be affected by pollutants. Proteomics provides a means of achieving high‐throughput analysis of effects on protein populations and sub‐populations with the potential to identify novel biomarkers. This review summarises the main approaches currently used in this area and assesses the potential of proteomics for identification of novel toxicity targets.
Expression, purification, and physicochemical characterization of theN‐terminal active site of human angiotensin‐I converting enzyme
Authors: Vamvakas Sotirios‐Spyridon M. , Leondiadis Leondios , Pairas George , Manessi‐Zoupa Evy , Spyroulias Georgios A. , Cordopatis Paul
Published: September 2006

We have cloned, over expressed, and purified one of the two catalytic domains (residues Ala361to Gly468, ACE‐N) of human somatic angiotensin‐I converting enzyme inEscherichia coli.This construct represents theN‐catalytic domain including the two binding motifs and the 23 amino acid spacers as well as some amino acid residues before and after the motifs that might help in correct conformation. The overexpressed protein was exclusively localized to insoluble inclusion bodies. Inclusion bodies were solubilized in an 8‐Murea buffer. Purification was carried out by differential centrifugation and gel filtration chromatography under denaturing conditions. About 12 mg of ACE‐N peptide per liter of bacterial culture was obtained. The integrity of recombinant protein domain was confirmed by ESI/MS. Structural analysis using CD spectroscopy has shown that, in the presence of TFE, the ACE‐N protein fragment has taken a conformation, which is consistent with the one found in testis ACE by X‐ray crystallography. This purification procedure enables the production of an isotopically labeled protein fragment for structural studying in solution by NMR spectroscopy. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Impurity induced inter‐tube conductance in double‐wall carbon nanotubes
Authors: Uryu Seiji , Ando Tsuneya
Published: September 2006

Inter‐tube conductance in finite‐length double‐wall carbon nanotubes with impurities is numerically studied. In the absence of impurities the conductance drastically decreases due to cancellation of inter‐tube coupling at different sites when the edges of the double‐wall region are smoothed. This suppression is reduced in the presence of impurities and the averaged conductance increases with increase of the length. This indicates that irregular position dependence of inter‐tube coupling caused by impurities induces inter‐tube transfer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Thermal effects in Raman spectra of hexagonal boron nitride and nanotube‐containing boron nitride soot
Authors: Arutyunyan N. R. , Obraztsova E. D. , Silly M. , Jaffrennou P. , Attal‐Tretout B. , Loiseau A. , Chuvilin A. L.
Published: September 2006

The temperature‐induced changes in Raman spectra of two BN‐based materials: a hexagonal boron nitride and soot with single‐wall BN nanotubes, have been measured in temperature range 77–600 K in course of heating in the oven/cryostat cell. A nonlinear temperature dependence of the tangential Raman mode position (being at 1366 cm–1 at room temperature) has been observed for both materials. In the temperature range 350–600 K a linear approximation of the tangential Raman mode shifting was applicable. The measured rates were –0.014 cm–1/K (for h‐BN) and –0.027 cm–1/K (for the nanotube‐containing sample). The effects of the oven and laser heating have been compared. Under the laser heating with the same power density the nanotube‐containing soot demonstrated much bigger shifts (up to 30 cm–1) than h‐BN. The data obtained are useful for in‐situ diagnostics of different BN‐based phases in course of synthesis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excitons in carbon nanotubes
Authors: Maultzsch J. , Pomraenke R. , Reich S. , Chang E. , Prezzi D. , Ruini A. , Molinari E. , Strano M. S. , Thomsen C. , Lienau C.
Published: September 2006

We present two‐photon excitation luminescence experiments on carbon nanotubes which show the excitonic origin of the optical excitations. The two‐photon allowed exciton state, which has even parity under rotation about the U‐axis, is roughly 300 meV above the one‐photon active, odd‐parity state. This indicates exciton binding energies on the order of 400 meV for nanotubes with diameters around 8 Å. Ab‐initio calculations of the exciton wavefunctions and energies are in good agreement with our experimental results, confirming the predictions on the symmetry of the exciton states. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rotor–stator phases of fullerenes with cubane derivatives: A novel family of heteromolecular crystals
Authors: Pekker S. , Kováts É. , Oszlányi G. , Bényei Gy. , Klupp G. , Bortel G. , Jalsovszky I. , Jakab E. , Borondics F. , Kamarás K. , Faigel G.
Published: September 2006

We present the formation, structure and properties of a new family of molecular crystals of distinct rotating and static components: the derivatives of fullerenes with cubane. The new crystals consist of alternating arrays of the constituents, stabilized by the recognition of the complementary molecular surfaces. The concave cubanes match six rotating fullerenes in octahedral configuration, while the six nearest neighbours of the convex fullerenes may form either octahedral or trigonal prismatic configurations. Fullerenes rotate freely in the ‘molecular bearing’ of cubanes. Lower symmetry crystals of similar properties form when cubane is replaced by 1,4‐diethynyl cubane. The following properties will be discussed: (i) The significant size and shape recognition makes possible the design of the crystal structure of new higher fullerenes and substituted cubane derivatives. (ii) The phase diagram of the rotor–stator crystals can be constructed in terms of the ball diameter of rotating fullerenes. (iii) The molecular geometry of the constituents has an influence on the structure and dynamics of the lower symmetry variants. (iv) At elevated temperatures the decomposition of cubane or diethynyl cubane induces topochemical copolymerization with the surrounding fullerenes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Shape‐selective synthesis of II–VI semiconductor nanowires
Authors: Fasoli A. , Colli A. , Hofmann S. , Ducati C. , Robertson J. , Ferrari A. C.
Published: September 2006

Polar II–VI semiconductors can nucleate in complex shapes ranging from nanowires to nanoribbons, nanosaws and multipods. Here we demonstrate the deterministic and fully reproducible shape‐selective growth of several morphologies of CdSe and ZnTe nanocrystals by a steady‐state vapour transport process. A simple pressure‐based precursor‐flow shutter excludes any effects of temperature ramping, ensuring reproducible shape selectivity for each set of deposition parameters. Once thermal gradients are eliminated, we show that the transition from one nanocrystal shape to another is controlled just by the interplay of precursor impinging on the substrate (ruled by the powder temperature T P) and sample surface kinetics (ruled by the sample temperature T S). Furthermore, a regime is found where seeded, epitaxial growth of CdSe nanorods becomes dominant over the conventional catalyst‐assisted nucleation. This allows the fabrication of vertical nanorod arrays free of any metal contamination. Seeded growth of branched and tetrapod‐like nanocrystals is also possible by further optimisation of the growth parameters. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simultaneous alignment and dispersion of carbon nanotubes with lyotropic liquid crystals
Authors: Lagerwall Jan P. F. , Scalia Giusy , Haluska Miroslav , Dettlaff‐Weglikowska Ursula , Giesselmann Frank , Roth Siegmar
Published: September 2006

We demonstrate that single‐wall carbon nanotubes (SWCNTs) can be macroscopically aligned by means of templating in a lyotropic nematic liquid crystal (LC), a self‐assembling anisotropic fluid with orientational but no translational order. The CNTs spontaneously adopt the alignment of the host, as we verify by means of resonant Raman spectroscopy. The aqueous LC host, based on the surfactant SDS, simultaneously keeps the nanotubes well dispersed over time scales of months or longer. The LC can be loaded with CNTs to almost the same extent as the standard isotropic 1% surfactant solutions normally used for dispersing CNTs without any optically visible bundling occurring. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orientation of OH terminal groups in oligo(ethylene glycol)‐terminated self‐assemblies: results of ab initio modeling
Authors: Malysheva Lyuba , Onipko Alexander , Liedberg Bo
Published: September 2006

Ab initio optimization of periodic arrays of HS(CH2)3CONH‐EG3 [EGn = (CH2CH2O)n H], which are used to model real self‐assembled monolayers (SAMs) terminated by oligomers of ethylene glycol (OEGs), favors a molecular geometry with a strong distortion of the OH tail group. The distortion effect is conformation dependent and appears exclusively in assemblies of helical OEGs. Helical SAM structures with the O–H bond directed towards the substrate surface exhibits a lower energy than the corresponding all trans SAMs with OH group oriented towards the vacuum interface. In view of strict limitations in molecular complexity and basis set for this kind of calculations, we tested the obtained molecular geometry as the starting point for performing optimization of the HS(CH2)15CONH‐EG6 molecule with the use of BP86/6‐31G* method/basis set provided by Gaussian03. It is found that the observed trend in OH tail group orientation survives and is consistent with a wealth of experimental data available for this type of SAMs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quasi one‐dimensional ceramic nanostructures spontaneously formed by combustion synthesis
Authors: Huczko A. , Lange H. , Bystrzejewski M. , Rutkowska A. , Cudziło S. , Szala M. , Wee A. T. S.
Published: September 2006

Inorganic quasi one‐dimensional (quasi 1D) nanostructures (carbides, nitrides) were spontaneously and efficiently produced via a combustion synthesis. Silicon carbide (β‐SiC) nanofibres ca. 20–100 nm in diameter with the aspect ratio between 102 and 103 were isolated (with a 98% purity) from the products resulting from redox reaction between Si‐bearing compounds (mostly silicides) and perhalogenated hydrocarbons. The products were analysed by using XRD, Raman, and SEM/TEM techniques. The optical limiting performance of the nanofibres was evaluated. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Self‐assembly of carbon nanotube field‐effect transistors by ac‐dielectrophoresis
Authors: Taeger Sebastian , Sickert Daniel , Atanasov Petar , Eckstein Gerald , Mertig Michael
Published: September 2006

We report an entirely self‐assembly based method for the bottom‐up fabrication of carbon nanotube (CNT) field effect transistors (FETs). First, the single‐walled CNTs are dispersed in water by means of single‐stranded DNA. Thereafter, CNT connects are grown between adjacent metal electrodes by ac‐dielectrophoresis. Finally, to obtain high‐performance FETs, the metallic CNTs are eliminated by burning them through applying an intensive current while the semiconducting ones are switched off. In this way, we were able to produce multi‐tube CNT‐FETs with on/off ratios larger than 1000. Here we describe the preparation of the devices along with their microscopic and electrical characterization. Possible applications of the fabricated CNT‐FETs are gas‐ or biosensors. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Kataura plot over broad energy and diameter ranges
Authors: Jorio Ado , Araujo Paulo T. , Doorn Stephen K. , Maruyama Shigeo , Chacham Helio , Pimenta Marcos A.
Published: September 2006

The theoretical plot presenting the optical transition energies for carbon nanotubes as a function of tube diameter was proposed in 1999 and became the most used guide for researchers in the field. This work presents this plot obtained experimentally in a broad range of excitation laser energies (1.26–2.7 eV) and nanotube diameters (0.7–2.3 nm). The results include the poorly studied E S33 and E S44 optical transitions, and indicate the higher levels are not excitonic, but related to free electron–holes making band‐to‐band transitions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An automatic email distribution by using text mining and reinforcement learning
Authors: Ueda Yoshihiro , Narita Hitoshi , Kato Naotaka , Hayashi Katsuaki , Nambo Hidetaka , Kimura Haruhiko
Published: September 2006

The authors created a system to automatically distribute inquiry email from electronic mail systems or the Web to the appropriate supervisor. The proposed method gathers document data created by the supervisors, calculates the tf·idf value and the idf/conf value for the words that appear in the documents, and then creates two types of dictionaries for each supervisor. Moreover, the method features the use of Profit Sharing instead of conventional inductive learning for two weights of terms. Profit Sharing is one method of reinforcement learning. The system compares the inquiry email and the dictionaries, then calculates a score for each supervisor based on the word weights and match rates, and identifies a supervisor with a high score as the respondent. The authors performed evaluation experiments using real inquiry emails in order to evaluate the effectiveness of their method, and found the following. (1) Based on the distribution accuracy of specialists who distribute inquiry email, the accuracy necessary for practical use was obtained. (2) In distribution using only the tf·idf value and the idf/conf value, distribution accuracy sufficient for practical purposes was not obtained. (3) A practical level of distribution accuracy, roughly equivalent to that of the distribution specialists, was obtained through reinforcement learning of the word weights in (2). Finally, the authors evaluated the number of document files and noise necessary to obtain the practical level of accuracy in (3) and compared the accuracy in their method with that of a conventional text categorization method. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 82–95, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20387
Improvement of tumor detection performance in mammograms by feature selection from a large number of features and proposal of fast feature selection method
Authors: Nemoto Mitsutaka , Shimizu Akinobu , Hagihara Yoshihiro , Kobatake Hidefumi , Nawano Shigeru
Published: September 2006

The purpose of this study is to improve the detection accuracy for malignant tumor shadows on mammograms. More than 490 feature parameters are prepared, more than 10 times the number in previous studies, and the suboptimal feature set which is effective in the detection is selected from among them by the forward stepwise selection procedure. The results are presented in this paper. An experiment using 1698 actual mammograms shows that the number of false‐positive malignant tumor shadows is reduced by approximately 40% (from 1.98/image to 1.12/image) compared to the previous. The computational amount of the stepwise selection procedure is theoretically evaluated. It is described that if a larger number of sample images or a larger number of feature parameters than those used in this study are included, the computational amount becomes tremendous, making the process practically impossible. A new fast processing method is proposed, in which the features within the subset are selected in two stages. The new selection procedure is applied to the same data and a feature selection experiment is performed. It is found that the detection accuracy is almost the same and the speed of selection is improved. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 56–68, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20498
Recognition of positive/negative attitude and its application to a spoken dialogue system
Authors: Fujie Shinya , Ejiri Yasushi , Kikuchi Hideaki , Kobayashi Tetsunori
Published: September 2006

Dialogue between human subjects by voice is based on linguistic information contained in the utterance. In addition, the psychological state of the utterer and information complementing the dialogue are represented by prosody, facial expression, and head movement, making the dialogue proceed smoothly. Such information, which co‐occurs with the utterance and supports the smooth transmission of linguistic information, is called paralinguistic information. This paper considers the attitude of the utterer as represented by prosody and head gestures as paralinguistic information. Methods of recognizing such respective information are proposed, and a dialogue robot is realized on the basis of the proposed method. In the recognition of the utterance attitude by prosody, the positive or negative attitude of the utterance is recognized on the basis ofF0pattern and the phoneme duration. In the recognition of head gestures, a nod is defined as representing a positive attitude and a tilt or shake of the head as representing a negative attitude. These three motions are recognized with the optical flow as the feature parameters, using HMM as a stochastic model. It is shown experimentally that the proposed method achieves the same recognition ability as humans. It is also shown that a dialogue robot incorporating the proposed method achieves a rhythmic, efficient dialogue, which has not been the case in the past. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 45–55, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20508
An algorithm for disjoint paths in bubble‐sort graphs
Authors: Suzuki Yasuto , Kaneko Keiichi
Published: September 2006

Ann‐dimensional bubble‐sort graph is regular and symmetric. It hasn! nodes and (n−1)n!/2 edges while its connectivity and diameter aren−1 andn(n−1)/2, respectively. Bubble‐sort graphs are attracting attention because of their simple, symmetric, and recursive structure. In this paper, for ann‐bubble‐sort graph, we give anO(n5)‐time algorithm that solves the node‐to‐set disjoint paths problem: Given a source nodesand a set D = d1, d2, …, dk(s ∉ D) ofkdestination nodes in ak‐connected graphG, findkpaths fromstodi(1≤i≤k) that are node‐disjoint except fors. Once thesekpaths are obtained, they achieve fault tolerance; that is, at least one path can survive withk−1 faulty components. We also show that the total length ofn−1 paths given by the algorithm isO(n3). Computer experiment results show that the average time complexity of the algorithm and the average total length of the paths given by the algorithm areO(n4.7) andO(n3.0), respectively. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 27–32, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20518
A structured representation of researcher interests for filtering of research journals and proceedings papers
Authors: Yamamoto Masao , Yajima Hiroshi , Kinukawa Hiroshi
Published: September 2006

There is increasing demand for a filtering system for scientific papers that can be utilized by researchers in business organizations. In conventional paper filtering systems, relevant papers are selected without sufficiently representing the researcher's interest structure, and thus the accuracy of filtering is not satisfactory. The purpose of this paper is to solve this problem and to propose a method of providing a structured representation of the researcher's interests by clustering papers of interest to the researcher. The similarity of newly appearing papers to the structured representation is calculated and the result of filtering is presented with rankings, resulting in both accuracy and convenience of use. With three researchers as the participants, an experimental evaluation of the filtering was performed by an N‐fold cross‐validation test, using 2 years of papers from proceedings journals in information science. An accuracy of 44% to 69% was achieved, 9.6% to 17.9% higher than the results of a filtering system without clustering used as the baseline. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(12): 1–16, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20664
Measuring the Intrapersonal Component of Psychological Empowerment: Confirmatory Factor Analysis of the Sociopolitical Control Scale
Authors: Peterson N. Andrew , Lowe John B. , Hughey Joseph , Reid Robert J. , Zimmerman Marc A. , Speer Paul W.
Published: September 2006

The Sociopolitical Control Scale (SPCS) is a widely used measure of the intrapersonal component of psychological empowerment. Confirmatory factor analyses (CFA) were conducted with data from two samples to test the hypothesized structure of the SPCS, the potential effects of method bias on the measure's psychometric properties, and whether a revised version of the scale (SPCS‐R) yielded improved model fit. Sample 1 included 316 randomly selected community residents of the Midwestern United States. Sample 2 included 750 community residents of the Northeastern U.S. Results indicated that method bias from the use of negatively worded items had a significant effect on the factor structure of the SPCS. CFA of the SPCS‐R, in which negatively worded items were rephrased so that all statements were positively worded, supported the measure's hypothesized two‐factor structure (i.e., leadership competence and policy control). Subscales of the SPCS‐R were found reliable and related in expected ways with measures of community involvement. Implications of the study for empowerment‐based research and practice are described, and strategies to further develop the SPCS are discussed.
Large neutral amino acids in the treatment of phenylketonuria (PKU)
Authors: Matalon R. , Michals‐Matalon K. , Bhatia G. , Grechanina E. , Novikov P. , McDonald J. D. , Grady J. , Tyring S. K. , Guttler F.
Published: September 2006

Large neutral amino acids (LNAAs) have been used on a limited number of patients with phenylketonuria (PKU) with the purpose of decreasing the influx of phenylalanine (Phe) to the brain. In earlier studies on mice with PKU (ENU2/ENU2), LNAAs were given and a surprising decline in blood Phe concentrations was observed. The formula used in the mouse experiment (PreKUnil) lacked lysine. Therefore, a new formulation of LNAAs (NeoPhe) was developed, introducing changes in the concentration of some amino acids and adding lysine, so that such a mixture could be used in humans. The new formula was found to be effective in reducing blood Phe concentration in mice by about 50% of the elevated levels. Patients with PKU were given LNAAs and blood Phe concentrations were determined in an open‐label study. Three centres—in Russia, the Ukraine and the USA—took part in the study. NeoPhe was given at 0.5 g/kg per day in three divided doses to eight subjects with PKU and at 1.0 g/kg per day to three patients, for one week. The NeoPhe resulted in decrease of elevated blood Phe by 50% in both groups. The preliminary data from this study are encouraging and a double blind placebo‐controlled trial will be required to show long‐term efficacy and tolerance of LNAAs in the treatment of PKU.
Seed germination and seedling growth in the arrow bamboo Fargesia qinlingensis
Authors: Wang Wei , Franklin Scott B. , Cirtain Margaret C.
Published: September 2006

Improving natural regeneration of bamboos after they die following mass flowering is critical for conservation of giant pandas. However, little is known about factors that affect seed germination and seedling growth of bamboos. We studied seed germination and seedling growth in Fargesia qinlingensis, which mass flowered in a giant panda habitat in the Qinling Mountains of China in early 2000, in laboratory and greenhouse conditions. Seed germination rate was tested under light and dark conditions 5 and 12 months after seed collection. Germination rate displayed no significant difference under light or dark conditions 5 months after seed collection, but was significantly greater in the dark than under light 12 months after seed collection, suggesting light inhibition of seed germination. A 2×2 factorial design was conducted to test the effects of nitrogen (N fertilization and non‐N fertilization) and light [full sun and shade (i.e., 14% full sun)] on seedling growth and biomass allocation. N fertilization significantly increased seedling growth, resulting in greater seedling height, more branches, more leaves, greater stem biomass, and greater leaf biomass. Seedlings under 14% full sun conditions had a significantly lower percentage of biomass allocated to the stem. The root/shoot ratio was significantly greater in non‐N/shade than non‐N/full sun, while there was no significant difference in this ratio between N/shade and N/full sun, suggesting that nitrogen fertilization compensated for the effect of shade on biomass allocation. Our results suggest that N fertilization could be employed in restoration of F. qinlingensis stands after die‐off following mass flowering.
Flowering phenology and survival of two annual plants Impatiens noli‐tangere and Persicaria thunbergii co‐occurring in streamside environments
Authors: Suzuki Mayuko , Kaya Yuhdai , Ishida Takahide A. , Hattori Kouhei , Miki Kaori , Nakamura Takashi , Kimura Masahito T.
Published: September 2006

Flowering phenology of cleistogamous annual plants Impatiens noli‐tangere and Persicaria thunbergii was studied with reference to their mortality in streamside environments in northern Japan. I. noli‐tangere produced flower‐buds and flowers from late June to October, whereas P. thunbergii did so from mid‐August to October. Both species were often killed by rapid current and submergence after heavy rainfall, which was unpredictable in the timing and intensity. P. thunbergii was more tolerant to rapid current and submergence than I. noli‐tangere. Some individuals of I. noli‐tangere were killed by herbivory from sawfly larvae in summer, but P. thunbergii individuals were seldom killed by herbivory. In consequence, the percentage of individuals that survived until the end of September was higher in P. thunbergii than in I. noli‐tangere. These situations are assumed to select a long reproductive life in I. noli‐tangere and autumn flowering in P. thunbergii.
International diffusion and postcommunist electoral revolutions
Authors: Bunce Valerie J. , Wolchik Sharon L.
Published: September 2006

Over the past decade, a number of elections in postcommunist regimes perched between democracy and dictatorship have led to the triumph of liberal oppositions over illiberal incumbents or their anointed successors. The international diffusion of these electoral revolutions reflects the interaction among five factors: the long term development of civil society, expanded opportunities for democratic political change, the rise of collaborative networks among international democracy promoters, regional exporters of democracy and local oppositions, and, finally, careful application of an electoral approach to regime transition. The cross-national diffusion of the electoral model in this region, however, may have run its course, largely because of less supportive local and international conditions.