bluuebunny/crossref_metadata_2025 huggingface dataset:
Polythiophenes Containing Oligo(oxyethylene) Side Chains as a Thin Film on a ZnSe Single Crystal Surface
Authors: van Beek Rick , Jenneskens Leonardus W. , Zdravkova Aneliya N. , van der Eerden Jan P. J. M. , van Walree Cornelis A.
Published: May 2005

Summary: Two polythiophenes, containing either one (PTT) or two (PBTT) 2,5,8‐trioxanonyl side chains per repeating unit, were synthesized with the objective of developing hybrid inorganic/organic semiconductor systems. From absorption and fluorescence spectroscopy and cyclic voltammetry it appears that introduction of a second 2,5,8‐trioxanonyl side chain on a repeating unit leads to a very short conjugation length. Atomic Force Microscopy (AFM) performed on composites of the two polythiophenes and a ZnSe single crystal reveals excellent wetting of the crystal by the polymers, leading to the formation of thin films. For the PTT/ZnSe composite, good contact between the constituents is substantiated by a red‐shift of the PTT absorption relative to that of PTT on quartz. Fluorescence measurements indicate the occurrence of energy transfer from ZnSe to PTT, which might imply that there is electronic contact between ZnSe and PTT. Because of its highly distorted backbone, neither a significant red‐shift compared with a film on quartz nor excitation energy transfer was found for the thin film of PBTT deposited on ZnSe. Nevertheless, it is shown that the presence of polar 2,5,8‐trioxanonyl side chains guarantees strong binding of polythiophenes to the ZnSe surface.

AFM contact mode topographical image of a PBTT film cast onto a ZnSe single crystal.

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AFM contact mode topographical image of a PBTT film cast onto a ZnSe single crystal.
Chain Dynamics of Poly(oxyethylene) in Nanotubes of α‐Cyclodextrin by Solid‐State 2H NMR
Authors: Girardeau Tom E. , Leisen Johannes , Beckham Haskell W.
Published: May 2005

Summary: Solid‐state 2H NMR spectroscopy was used to examine the chain dynamics of perdeuterated poly(oxyethylene) (d‐POE) inside α‐cyclodextrin (α‐CD) nanotubes. The nanotubes were prepared by aqueous self‐assembly of α‐CD onto either low‐molecular‐weight (1.5 kg/mol) or high‐molecular‐weight (25.8 kg/mol) monodisperse d‐POE. At a given temperature, POE chain segments exhibit faster dynamics when included inside the CD nanotubes as compared to the bulk. Even at 150 K, when no large‐angle dynamics are detected in bulk POE, evidence for chain motions in the nanotube‐confined POE is observed. The 2H line shapes representing this motion were modeled by a discrete 3‐site jump using a ln‐Gaussian distribution of correlation times. An activation energy of 15 ± 1 kJ/mol was determined and the motion envisioned as gauche defects propagating along the primarily trans chains included within CD nanotubes. As the nanotube length decreased, the jump angle became much less defined and more isotropic motions were observed for POE segments at elevated temperatures (>270 K).

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Polymerization Kinetics and Characterization of Dual Cured Polyurethane‐Acrylate Nanocomposites for Laminates
Authors: Bertoldo Monica , Bronco Simona , Narducci Piero , Rossetti Stefano , Scoponi Marco
Published: May 2005

Summary: Four different types of montmorillonites have been dispersed by sonication at 50 °C into a propoxylated aromatic epoxy diacrylate oligomer to achieve interlayered or exfoliated nanocomposites. A thermally‐induced crosslinking reaction, forming a polyurethane network in the presence of 7 wt.‐% of a montmorillonite, has been promoted by addition of an allophanate modified polyisocyanurate based on hexamethylene diisocyanate. The kinetic behavior of the network formation has been studied at 25, 40 and 60 °C by following the disappearance of the isocyanate vibrational band found at 2 270 cm−1. A tight crosslinked polyurethane acrylate network has been achieved by a subsequent dual UV curing promoted by a photoinitiator mixture (0.6 wt.‐%) added to the reactive mixture because of further reactions occur to the acrylate double bonds. The photopolymerization kinetic has been investigated on the different thermally treated polyurethane nanocomposite networks by Real Time FTIR spectroscopy monitoring the changes of the IR band at 810 cm−1 assigned to the acrylate double bond vibrations. The influence of the different montmorillonite clays on the final nanocomposite morphology has been investigated by using XRD and SEM. Finally, the use of these mixtures as internal layer between two modified surface PET films has been also studied for the laminate production. The based‐PET laminate films have been characterized by determining the bending resistance and optical properties as a function of different nanofillers.

Bending resistance of the dual cured nanocomposite laminates containing 7 wt.‐% as a function of nanofiller types.

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Bending resistance of the dual cured nanocomposite laminates containing 7 wt.‐% as a function of nanofiller types.
Effect of the Addition of Toluene on the Structure and Properties of Styrene‐Isoprene‐Butadiene Rubber/Montmorillonite Nanocomposites
Authors: Zhang Zhenjun , Zhang Lina , Li Yang
Published: May 2005

Summary: Styrene‐isoprene‐butadiene rubber/montmorillonite nanocomposites were synthesized by the addition of toluene into clay and living anionic polymerization. These silicate layers (B‐M) were exfoliated within 30 min after polymerization initiation, whereas the layers in the nanocomposites prepared without using toluene (A‐M) were only partially exfoliated and not well‐dispersed in the matrix. The results of TEM and X‐ray diffraction revealed disperse silicates and a strong interaction between the terpolymer matrix and clay in the B‐M nanocomposites. The B‐M‐exfoliated nanocomposites exhibited higher decomposition and glass transition temperatures, storage moduli, tensile strengths and elongations at the break than those of the pure terpolymer and A‐M. With an organophilic montmorillonite (OMMT) content of 3 wt.‐%, the exfoliated nanocomposite exhibited the best thermal stability and mechanical properties. In addition, GPC and 1H NMR results showed that the introduction of OMMT caused a slight increase in the $\overline M _{\rm w}$ of terpolymer, but hardly affected the microstructure of the terpolymer independent of the preparation method. Thus, the addition of toluene plays an important role in enhancing the dispersion of OMMT, which leads to the improvement of the structure and properties of the B‐M nanocomposites.

TEM image of the SIBR/MMT nanocomposite.

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TEM image of the SIBR/MMT nanocomposite.
Bandwidth limitation of two‐port fed and self‐phased quadrifilar helix antennas
Authors: Amin M. , Cahill R.
Published: May 2005

The bandwidth of a resonant quadrifilar helix antenna (QHA) is shown to be strongly dependent on the design of the feed network. In this paper, we compare the impedance and radiation‐pattern performance of two QHAs driven by different feed arrangements. A qualitative explanation for the difference in the behaviour of the antenna is given by observing the amplitude and phase distribution of the current in the helices. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 11–15, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20886
Dual‐mode microstrip bandpass filter using circular patch resonator with two transmission zeros
Authors: Li JiaLin , Chen JianXin , Wang JianPeng , Xue Quan , Shao Wei , Xia Lei , Xue LiangJin
Published: May 2005

A microstrip dual‐mode bandpass filter (BPF) using a circular patch resonator is investigated in this paper. Unlike the conventional dual‐mode patch‐resonator bandpass filter studied in the literature, the introduced filter is perturbed by one circular hole in the northeast area of the patch. The filter has a simple topology and can implement elliptic‐function response characteristics. An experimental filter is optimally designed and fabricated, for the first time, in order to demonstrate the idea. Both the calculated and measured results are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 28–30, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20891
Dual‐band dual‐circularly‐polarized sector antenna for GPS and DAB systems
Authors: Lee Byungje , Harackiewicz Frances J. , Kong Ki‐Hyun , Byun Joonho , Yang Sung‐Hyun
Published: May 2005

The concept of a dual‐band dual‐circularly‐polarized antenna for GPS (Global Positioning System, 1575 MHz) and DAB (Digital Audio Broadcasting, 1452–1492 MHz) system is proposed. The generation of circular polarizations and reduction of an overall antenna‐element dimension are achieved by placing a partially filled high‐permittivity dielectric bar under the radiating edges of the patch. A patch‐antenna element based on the proposed method and a conventional antenna element with an air layer filling the whole volume under the patch are compared, and antenna‐dimension reduction of more than 30% is achieved using the proposed method. Finally, a sector‐type antenna is designed by employing the space‐diversity technique with the proposed antenna elements. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 43–46, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20896
A multifrequency microstrip antenna
Authors: Roy Jibendu Sekhar , Ghosh Jayanta
Published: May 2005

Investigations of a microstrip antenna for multifrequency operation are reported. The integral‐equation method, using IE3D software, is used for the analysis of the antenna. The antenna can be used to operate at four different resonance frequencies with broadside radiation patterns. The theoretical results are supported by experimental verification. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 63–65, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20902
Dual‐band millimeter‐wave/infrared focal‐plane arrays
Authors: Abdel‐Rahman M. , Lail B. , Boreman G. D.
Published: May 2005

In this paper, a novel arrangement for dual‐band millimeter‐wave and infrared focal plane array based on slot‐antenna‐coupled metal‐oxide‐metal diodes is demonstrated. The receiving properties for millimeter‐wave and infrared antenna‐coupled detector pixels are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 78–80, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20906
Reply to “Remark on Group Velocity, Negative and Ultra‐High Index of Refraction in Photonic Band Gap Materials”
Authors: Ojha S. P. , Srivastava Sanjeev K.
Published: May 2005

© 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 94–95, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20911
Enhancing quantum efficiency of MEH‐PPV through the reduction of chain aggregations by thermal treatments
Authors: Chou Hsuan‐Liang , Lin King‐Fu , Fan Yang‐Liang , Wang Ding‐Chang
Published: May 2005

The quantum efficiencies of photoluminescence (PL) and electro‐luminescence (EL) of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV) were significantly increased by heat treatments under vacuum with further removing the undissolved portion. The UV–vis absorption was found to decrease with heating time, while PL intensity increased. The maximum PL quantum yield was 6.5 times that of the untreated MEH‐PPV, which was attributed to the reduction of chain aggregations and the interruption of conjugation length. The maximum EL quantum yield of their prepared ITO/PANI/MEH‐PPV/Ca/AL light emitting diodes (PLED) was 46 (at 3 V) times that of the untreated sample. A typical turn‐on voltage of 2.5 V for MEH‐PPV PLED was able to decrease to 1 V after heat treatments, which was believed to result from the decrease of cis linkages in the polymer chains as revealed by the 1H NMR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1705–1711, 2005
Hybrid DFT study of the hyperfine coupling constants of methyl radicals in model matrix lattices
Authors: Takada Tomoya , Tachikawa Hiroto
Published: May 2005

The hyperfine coupling constants of hydrogen atom (H‐hfcc's, aH) of methyl radical (CH3) in matrices have been calculated by means of the hybrid density functional theory (DFT) and ab initio methods in order to elucidate the effect of matrices on the H‐hfcc of CH3. Three typical matrices (X = CH4, H2, and Ar) were examined in the calculations. The systems calculated in the present work, denoted by CH3(X)n, are CH3(H2)n (n = 12 and 20), CH3(Ar)n (n = 12 and 18), and CH3(CH4)n (n = 12 and 18). The Møller–Plesset type 2 (MP2) and B3LYP methods were applied to the H‐hfcc calculation. The H‐hfcc of methyl radical was slightly perturbed by the interaction with matrices lattice, and it was shifted from that of free methyl radical (aH = −23.03 G). The mechanism of the shift of H‐hfcc of CH3 in matrices lattice was discussed on the basis of theoretical results. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Theoretical study of 1,2‐rearrangement in silylmethanethiol
Authors: Zhang Jie , Feng Shengyu , Feng Dacheng , Xie Ju
Published: May 2005

The 1,2‐rearrangements in silylmethanethiol were studied by ab initio molecular orbital theory. The structures of reactants, transition states, and products were fully optimized at the MP2(full)/6‐31G(d) levels. Based on the MP2(full)/6‐31G(d) geometries, harmonic frequencies were obtained. Energies were computed at the G3 level of theory with MP2(full)/6‐31G(d) zero‐point corrections. The results indicate that the 1,2‐rearrangement in silylmethanethiol may occur via two pathways. Pathway A involves the 1,2‐migration of mercapto group from carbon to silicon via a double three‐membered ring transition state, forming methylsilanethiol. The barrier for reaction A is 275.0 kJ/mol. Pathway B involves the 1,2‐migration of silyl group from carbon to sulfur via a four‐membered ring transition state, forming methylthiosilane. The barrier for reaction B is 262.3 kJ/mol. Thermodynamic and kinetic properties of the reactions were analyzed over a temperature range of 300–1,300K. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Improved accuracy of quantitative XPS analysis using predetermined spectrometer transmission functions with UNIFIT 2004
Authors: Hesse R. , Streubel P. , Szargan R.
Published: May 2005

The accuracy of quantitative XPS analysis can be improved using predetermined transmission functions. Two different calibration methods are used for estimating the transmission function T(E) of a photoelectron spectrometer, applying a survey spectra approach (SSA) and a quantified peak‐area approach (QPA) to minimize the quantification error. For the SSA method, Au, Ag and Cu spectra measured with the Metrology Spectrometer II have been used. The new QPA method was built up from Au 4f, Au 4d, Au 4p3/2, Ag 3d, Ag 3p3/2, Cu 3p, Cu 2p3/2, Ge 3p and Ge 2p3/2 standard peak areas, applying adequate ionization cross‐sections and mean free path lengths for different pass energies (10 and 50 eV), lens modes (large area, large area XL, small area 150) and x‐ray sources (Al/Mg Twin and Al Mono). In the energy range 200–1500 eV a transmission function T(E) = a0 + b1E (where a0, b1 and b2 are variable parameters) was found to give an appropriate approximation for eight tested spectrometer settings, implementing the largest changes in the case of pass energy variations. Determination and application of the transmission functions were integrated in the XPS analysis software (UNIFIT 2004) and tested by means of an Ni90Cr10 alloy. The results demonstrate the practicability of the SSA and QPA methods, giving decreased errors of <8% in comparison with errors up to 38% obtained using Wagner's sensitivity factors. Copyright © 2005 John Wiley & Sons, Ltd.
Types of firms generating network externalities and MNCs' co‐location decisions
Authors: Chang Sea‐Jin , Park Sekeun
Published: May 2005

This study identifies and examines sources of network externalities that influence MNCs to agglomerate their foreign operations in specific regions. Using data for Korean firms that invested in China, this study found that network externalities were sensitive to the types of firms constituting a regional network. It also found stronger network externalities within firms than across firms, from firms of the same nationality than from those of different nationalities, and from firms in the same industry than from those of different industries. As we defined the types of firms more precisely, distinctive curvilinear relationships between network externalities and the likelihood of co‐location emerged. Copyright © 2005 John Wiley & Sons, Ltd.
Is failure good?
Authors: Knott Anne Marie , Posen Hart E.
Published: May 2005

Approximately 80–90 percent of new firms ultimately fail. The tendency is to think of this failure as wasteful. We, however, examine whether there are economic benefits to offset the waste. We characterize three potential mechanisms through which excess entry affects market structure, firm behavior, and efficiency, then test them in the banking industry. Results indicate that failed firms generate externalities that significantly and substantially reduce industry cost. On average these benefits exceed the private costs of the entrants. Thus failure appears to be good for the economy. Copyright © 2005 John Wiley & Sons, Ltd.
Frontal lobe‐dependent functions in treated phenylketonuria: Blood phenylalanine concentrations and long‐term deficits in adolescents young adults
Authors: Feldmann R. , Denecke J. , Grenzebach M. , Weglage J.
Published: May 2005

Even early‐treated phenylketonurics may suffer from phenylalanine‐related deficits. Elevated phenylalanine concentrations can interfere with the development and function of the CNS. Outcome beyond childhood has not been extensively investigated. This long‐term study was performed to determine whether adolescents and young adults with PKU show frontal lobe‐dependent deficits when compared to diabetic patients. The comparative study covered 35 PKU patients, 13–21 years of age (mean 17.8 years), and 35 diabetic patients matched for sex, age and socioeconomic status. Patients were assessed for IQ (Culture Fair Intelligence Test), information processing (Trail Making Test), and selective and sustained attention (Stroop Task, Test d‐2). Assessments were repeated within a 3‐year follow‐up. PKU patients showed no increase in blood phenylalanine concentrations at follow‐up. They had significantly poorer test results than the diabetic patients at both assessment times. Within the tests, however, this was due to reduced performance speed but not to deficits in specific frontal lobe‐dependent functions. Elevated phenylalanine concentrations seem to exert a global effect slowing performance speed. This effect is enduring in adolescence and early adulthood.
Elevated plasma citrulline and arginine due to consumption of Citrullus vulgaris (watermelon)
Authors: Mandel H. , Levy N. , Izkovitch S. , Korman S. H.
Published: May 2005

A 19‐month‐old girl with developmental delay was found to have moderately elevated plasma citrulline and mildly elevated plasma arginine concentrations. Dietary history revealed that she consumed large quantities of watermelon (Citrullus vulgaris), a fruit containing high free citrulline and arginine concentrations. In order to determine whether the patient's high watermelon intake could account for her elevated plasma citrulline and arginine concentrations, we studied the response of plasma citrulline and arginine to ingestion of watermelon in six healthy adult volunteers. All developed markedly elevated plasma citrulline (mean maximum 593 μmol/L, range 386–1069) and moderately elevated plasma arginine (mean maximum 199 μmol/L, range 128–251). Physicians and laboratory personnel performing metabolic investigations should be aware of watermelon‐induced citrullinaemia. Its hallmarks are elevated plasma citrulline, and to a lesser extent arginine, in the absence of orotic or arginosuccinic aciduria or hyperammonaemia. This phenomenon has implications for the management of patients with urea cycle and related disorders.
A survey of Japanese patients with Menkes disease from 1990 to 2003: Incidence and early signs before typical symptomatic onset, pointing the way to earlier diagnosis
Authors: Gu Y. H. , Kodama H. , Shiga K. , Nakata S. , Yanagawa Y. , Ozawa H.
Published: May 2005

Menkes disease (MNK) is a lethal, X‐linked recessive disorder of copper metabolism dominated by neurodegenerative symptoms and connective tissue disturbances. The incidence of MNK in Asia is not known. Most patients die by the age of 3 years if adequate treatment is not carried out. Early parenteral administration of copper can prevent the neurological disturbances and lead to a better outcome. In the present study, a survey on MNK in Japan was performed. There were in total 53 live‐born Japanese patients with MNK collected from 1990 to 2003, including two females. The incidence of live‐born MNK patients between 1992 and 2002 was 2.8 per million live births (95% confidence interval (CI): 1.8 to 3.7), 4.9 per million male live births (95% CI: 3.2 to 6.6). One‐third of the patients were born before 37 weeks or weighing less than 2500 g. Seventeen per cent were born both before 37 gestational weeks and weighing less than 2500 g. These proportions were higher than those in Japanese live‐birth babies according to a nationwide estimate. The hair on these Japanese patients appeared not only as white or grey but also brown and blond. We also found that many signs had been noted before the patient was brought to a hospital with typical symptoms. These signs may be a clue to early diagnosis of MNK.
Congenital cataract, muscular hypotonia, developmental delay and sensorineural hearing loss associated with a defect in copper metabolism
Authors: Horváth R. , Freisinger P. , Rubio R. , Merl T. , Bax R. , Mayr J. A. , Shawan  , Müller‐Höcker J. , Pongratz D. , Moller L. B. , Horn N. , Jaksch M.
Published: May 2005

Deficiencies of different proteins involved in copper metabolism have been reported to cause human diseases. Well‐known syndromes, for example, are Menkes and Wilson diseases. Here we report a patient presenting with congenital cataract, severe muscular hypotonia, developmental delay, sensorineural hearing loss and cytochrome‐c oxidase deficiency with repeatedly low copper and ceruloplasmin levels. These findings were suggestive of a copper metabolism disorder. In support of this, the patient's fibroblasts showed an increased copper uptake with normal retention. Detailed follow‐up examinations were performed. Immunoblotting for several proteins including ATP7A (MNK or Menkes protein), ATP7B (Wilson protein) and SOD1 showed normal results, implying a copper metabolism defect other than Wilson or Menkes disease. Sequence analysis of ATOX1 and genes coding for proteins that are known to play a role in the mitochondrial copper metabolism (COI–III, SCO1, SCO2, COX11, COX17, COX19) revealed no mutations. Additional disease genes that have been associated with cytochrome‐c oxidase deficiency were negative for mutations as well. As beneficial effects of copper histidinate supplementation have been reported in selected disorders of copper metabolism presenting with low serum copper and ceruloplasmin levels, we initiated a copper histidinate supplementation. Remarkable improvement of clinical symptoms was observed, with complete restoration of cytochrome‐c oxidase activity in skeletal muscle.
Preparation of 5‐amino‐4‐imidazole‐N‐succinocarboxamide ribotide, 5‐amino‐4‐imidazole‐N‐succinocarboxamide riboside and succinyladenosine, compounds usable in diagnosis and research of adenylosuccinate lyase deficiency
Authors: Zikánová M. , Krijt J. , Hartmannová H. , Kmoch S.
Published: May 2005

The enzyme adenylosuccinate lyase (ADSL) intervenes twice in the biosynthesis of adenine nucleotides. ADSL deficiency is an inherited metabolic disease characterized by various degrees of psychomotor retardation and accumulation of dephosphorylated enzyme substrates 5‐amino‐4‐imidazole‐N‐succinocarboxamide riboside (SAICAr) and succinyladenosine (SAdo) in body fluids. Severity of symptoms seems to correlate with residual activity of mutant enzyme and with SAdo/SAICAr concentration ratio in cerebrospinal fluid. To better understand the pathogenetic mechanisms of the disease symptoms, studies of catalytic properties of mutant enzymes together with in vitro and in vivo experiments utilizing SAICAr and SAdo must be performed. Such studies require availability of both ADSL substrates, 5‐amino‐4‐imidazole‐N‐succinocarboxamide ribotide (SAICAR) and succinyladenosine 5′‐monophosphate (SAMP) and their dephosphorylated products in sufficient amounts and purity. Except for SAMP, none of these compounds is commercially available and they must therefore be synthesized. SAICAR was prepared by recombinant human ADSL‐catalysed reaction of AICAR (5‐aminoimidazole‐4‐carboxamide) with fumarate and isolated by thin‐layer chromatography. SAICAr and SAdo were prepared by calf intestine alkaline phosphatase‐catalysed dephosphorylation of SAICAR and SAMP and isolated on cation‐ and anion‐exchange resin columns. The procedures described are easily scalable and provide high yields of sufficiently pure products for use in experiments related to studies of pathogenetic mechanisms in ADSL deficiency.
Normal acylcarnitine levels during confirmation of abnormal newborn screening in long‐chain fatty acid oxidation defects
Authors: Browning M. F. , Larson C. , Strauss A. , Marsden D. L.
Published: May 2005

We report two infants identified by tandem mass spectrometry (MS/MS) of neonatal blood spot acylcarnitines and confirmed by molecular genetic analysis to have long‐chain fatty acid oxidation defects. In both cases, acylcarnitine concentrations in confirmatory plasma samples were normal. None the less, molecular testing identified trifunctional protein (TFP) deficiency (McKusick 600890) and very long‐chain acyl‐CoA dehydrogenase (VLCAD) deficiency (McKusick 201475).
The 625G>A SCAD gene variant is common but not associated with increased C4‐carnitine in newborn blood spots
Authors: Maldegem B. T. van , Waterham H. R. , Duran M. , Vlies M. van der , Woerden C. S. van , Bobu L. L. , Wanders R. J. A. , Wijburg F. A.
Published: May 2005

The 625G>A variant of the short‐chain acyl‐CoA dehydrogenase (SCAD) gene is considered to confer susceptibility for developing ‘clinical SCAD deficiency’ and appears to be common in the general population. To determine the frequency of the 625G>A variant in The Netherlands, we analysed 1036 screening cards of 5‐ to 8‐day‐old newborns and found 5.5% homozygous and 31.3% heterozygous for the 625G>A variant. An increased blood/plasma C4‐carnitine concentration is considered to be one of the biochemical characteristics of SCAD deficiency. To explore the correlation of C4‐carnitine levels with the 625G>A variant, we determined the C4‐carnitine concentration, as well as the ratio of C4‐ to free carnitine, in blood spots from newborns, who were detected as homozygous, heterozygous or noncarriers for the gene variant. No significant differences were found between these groups. Our study demonstrates a high frequency of the 625G>A SCAD gene variant in the Dutch population, but no correlation to significantly increased C4‐carnitine levels in blood spots taken between the 5th and 8th days of life. This latter observation might be the result of the relatively late timing of neonatal screening in our country, implying that fatty acid oxidation disorders may be missed at that stage. If the 625G>A variant is associated with clinical SCAD deficiency, the high frequency of the variant suggests a possible involvement of SCAD deficiency in the pathogenesis of common disorders, probably in relation to other genetic and/or environmental factors. However, homozygosity for the 625G>A variant might be only a biochemical phenomenon, representing a ‘nondisease’.
Evaluation of three biochemical markers in the monitoring of Gaucher disease
Authors: Vellodi A. , Foo Y. , Cole T. J.
Published: May 2005

Several markers have been developed for the biochemical monitoring of Gaucher disease. Three of the most commonly used markers are acid phosphatase, angiotensin‐converting enzyme (ACE) and chitotriosidase. The rationale for using all three concurrently is not clear. A retrospective study was therefore carried out on data collected from 28 paediatric patients treated with enzyme replacement therapy. All three markers fell with time. However, chitotriosidase showed the steepest time trend, the largest trend by case interaction, and the lowest residual variance, making it the most reliable of the three. ACE correlated strongly with chitotriosidase, but acid phosphatase did not correlate well with either and also had the largest residual variance, indicating that it was too ‘noisy’ to be informative. The absence of a ‘gold standard’ for assessing Gaucher disease complicates the interpretation of these findings, but they suggest that acid phosphatase be dropped from routine clinical practice, and that chitriosidase be used in preference to ACE.
Orthotopic liver transplantation from a living‐related donor in an infant with a peroxisome biogenesis defect of the infantile Refsum disease type
Authors: Maldergem L. Van , Moser A. B. , Vincent M.‐F. , Roland D. , Reding R. , Otte J.‐B. , Wanders R. J. , Sokal E.
Published: May 2005

Peroxisomal biogenesis defects include a number of severe neurodevelopmental disorders, among which infantile Refsum disease (IRD) occupies the mildest end of the spectrum. Although high docosahexaenoic acid (DHA) and low phytanic acid diets can correct some of the biochemical defects, they have not consistently altered the progressive course of the disease. We carried out orthotopic liver transplantation (OLT) in a mildly symptomatic 6‐month‐old infant who was a sibling of a severely neurologically impaired older sister. After transplantation the clinical course of this young child appeared much improved by comparison to her older sister. She walked alone at 4 years, had acceptable social interaction and had a noticeable recovery of audition. After transplantation her biochemical parameters were significantly improved: phytanic acid and very long‐chain fatty acid (VLCFA) serum concentrations decreased. Abnormal bile acids disappeared from plasma. Although the OLT did not result in a cure of the disorder, the clinical and biochemical results suggest that OLT should be considered in mildly symptomatic patients.
On a Test of Dimensionality in Redundancy Analysis
Authors: Takane Yoshio , Hwang Heungsun
Published: May 2005

Lazraq and Cléroux (Psychometrika, 2002, 411–419) proposed a test for identifying the number of significant components in redundancy analysis. This test, however, is ill-conceived. A major problem is that it regards each redundancy component as if it were a single observed predictor variable, which cannot be justified except for the rare situations in which there is only one predictor variable. Consequently, the proposed test leads to drastically biased results, particularly when the number of predictor variables is large, and it cannot be recommended for use. This is shown both theoretically and by Monte Carlo studies.
Specific inhibition of HIV‐1 replication by short hairpin RNAs targeting human cyclin T1 without inducing apoptosis
Authors: Li Zhaoyang , Xiong Yong , Peng Yu , Pan Ji‧an , Chen Yu , Wu Xiaoyun , Hussain Snawar , Tien Po , Guo Deyin
Published: May 2005

RNA interference (RNAi), a sequence‐specific RNA degradation mechanism mediated by small interfering RNA (siRNA), can be used not only as a research tool but also as a therapeutic strategy for viral infection. We demonstrated that intracellular expression of short hairpin RNA (shRNA) targeting human cyclin T1 (hCycT1), a cellular factor essential for transcription of messenger and genomic RNAs from the long terminal repeat promoter of provirus of human immunodeficiency virus type 1 (HIV‐1), could effectively suppress the replication of HIV‐1. We also showed that downregulation of hCycT1 did not cause apoptotic cell death, therefore, targeting cellular factor hCycT1 by shRNAs may provide an attractive approach for genetic therapy of HIV‐1 infection in the future.
Molecular cloning and characterization of the copper/zinc and manganese superoxide dismutase genes from the human parasiteClonorchis sinensis
Authors: LI A. H. , KONG Y. , CHO S. H. , LEE H. W. , NA B. K. , PAK J. K. , KIM T. S.
Published: May 2005

A copper/zinc superoxide dismutase (Cu/ZnSOD) gene and a manganese superoxide dismutase (MnSOD) gene of the human parasiteClonorchis sinensishave been cloned and their gene products functionally characterized. GenesCu/ZnSODandMnSODencode proteins of 16 kDa and 25·4 kDa, respectively. The deduced amino acid sequences of the two genes contained highly conserved residues required for activity and secondary structure formation of Cu/ZnSOD and MnSOD, respectively, and show up to 73·7% and 75·4% identities with their counterparts in other animals. The genomic DNA sequence analysis of Cu/ZnSOD gene revealed this as an intronless gene. Inhibitor studies with purified recombinant Cu/ZnSOD and MnSOD, both of which were functionally expressed inEscherichia coli, confirmed that they are copper/zinc and manganese-containing SOD, respectively. Immunoblots showed that bothC. sinensisCu/ZnSOD and MnSOD should be antigenic for humans, and both, especially theC. sinensisMnSOD, exhibit extensive cross-reactions with sera of patients infected by other trematodes or cestodes. RT-PCR and SOD activity staining of parasite lysates indicate that there are no significant differences in mRNA level or SOD activity for both species of SOD, indicating cytosolic Cu/ZnSOD and MnSOD might play a comparatively important role in theC. sinensisantioxidant system.
Genetic homogeneity within Leishmania (L.) infantum isolated from human and dogs: the relationship with the sandfly fauna distribution in endemic areas of Nueva Esparta State, Venezuela
Authors: RODRIGUEZ N. M. , DE GUGLIELMO Z. , BARRIOS M. A. , BARRIOS R. M. , ZERPA O. , FELICIANGELI M. D.
Published: May 2005

Leishmania infantum has been described as a highly polymorphic group of parasites, responsible for visceral leishmaniasis and cutaneous leishmaniasis. In this paper we report the life-cycle of L. (L.) infantum in an endemic area of visceral leishmaniasis in Venezuela, by using molecular diagnosis and characterization of parasites isolated from dogs, humans with visceral leishmaniasis and sand flies. The molecular characterization was carried out by use of kDNA restriction analysis, dot-blot hybridization with species-specific probes and RFLP of the PCR products. The results demonstrated that L. (L.) infantum is the parasite responsible for VL in the island. The parasites were revealed to be genetically homogeneous with no intra-specific differences between isolates from different individuals. The highest homology of the isolates was with L. (L.) infantum from the Old World rather than with L. (L.) chagasi from the New World. Additionally, we report the geographical distribution of Lutzomyia longipalpis, and the relationship with the transmission of L. (L.) infantum in the studied area.
Use of micro-rotation imaging to study JNK-mediated cell survival inTheileria parva-infected B-lymphocytes
Authors: LIZUNDIA R. , SENGMANIVONG L. , GUERGNON J. , MÜLLER T. , SCHNELLE T. , LANGSLEY G. , SHORTE S. L.
Published: May 2005

Lymphocytes infected with the protozoan parasiteTheileria parvaare transformed to permanently proliferating cells, an event underlying the pathology of the disease. However, the molecular signalling mediating this process is complex and poorly understood. Here, we show that down-regulation of JNK signalling by transient over expression of a dominant-negative mutant of JNK (JNK-APF) significantly increases Annexin-V-phycoerythrin (V-PE) labelling on infected B cell populations observed using flow cytometry. To establish whether this increase was specifically due to apoptosis, we used a novel single-cell imaging method: micro-rotation (MR)-imaging, designed to allow high-resolution 3-dimensional imaging of single cells in suspension. With this method we visualized subcellular patterns of V-PE uptake and chromatin organization in lymphocytes co-transfected with JNK-APF and GFP-tagged histone-H2B. This single-cell approach allowed us to clearly reveal characteristic apoptotic phenotypes, whose patterns reflected progressive states of programmed cell death due to JNK down-regulation. Our results strongly suggest a role for JNK in the survival ofTheileria-infected B cells, and demonstrate the powerful utility of a new and unique 3-dimensional imaging method for living cells in suspension.
Progenesis in digenean trematodes: a taxonomic and synthetic overview of species reproducing in their second intermediate hosts
Authors: LEFEBVRE F. , POULIN R.
Published: May 2005

Precocious egg production, i.e. progenesis, has been documented for a number of species in scattered reports throughout the trematode literature. The last 2 extensive studies on the subject date from Buttner in the early 1950s (in French) and from Tang in the early 1980s (in Chinese). Overall, 43 species were then known for their ability to produce eggs at the metacercarial stage while still in the second intermediate host. Here, we update the list, and document the existence of progenesis in a total of 79 digenean trematode species, for which we provide information on the taxonomy of the hosts, the facultative or obligate character of progenesis, relevant references, as well as some other pertinent biological information. We then review the subject by asking 7 questions of fundamental evolutionary importance. These include: What favours progenetic development? What are the associated costs and benefits? How are progenetic eggs released from the host? While exposing the various opinions of previous authors, we attempt to give a synthetic overview and stress on the importance of the metacercarial cyst wall (whether it is present, and if so its thickness) in the evolution and the adoption of a progenetic life-cycle.
Effect of parasitism on plasma sex-specific proteins inCyphocarax gilbert(Teleost, Curimatidae)
Authors: DA SILVA L. GOMES , AZEVEDO J. S. , SILVA-NETO M. A. , LIMA N. R. WILLE , DANSA-PETRETSKI M.
Published: May 2005

Cyphocarax gilbert(Szidat, L., 1948) is a fish commonly found in coastal drainage of eastern Brazil. This fish is sometimes caught with signs of infection by the crustaceanRiggia paranensis, a haematophagous parasite. A remarkable feature of infected fish is that they lack gonads. In this paper we have analysed the frequency of parasitism, the gonadal development of non-infected fish and the profile of plasma proteins in both infected and non-infected specimens. Two reproductive periods/year were observed, beginning in February and August. On average, 40% of fish were infected, in the Itabapoana River (Brazil). Sex-specific proteins were identified by electrophoresis. SDS-PAGE analysis demonstrated that a 143 kDa female-specific glycolipoprotein (FSP) is a calcium-binding phosphoprotein. FSP was isolated through ultracentrifugation and SDS-PAGE analysis showed that the native protein is composed of three polypeptides of 143, 100 and 70 kDa. Both FSP and a 33 kDa male-specific protein (MSP) are absent from infected fish plasma. FSP levels in female plasma changes with the developmental stage of gonads. Altogether these data suggest that the FSP corresponds to fish vitellogenin. Furthermore, the absence of the above-mentioned proteins in infected fish suggests thatR. paranensismight interfere with the regular hormonal process of fish vitellogenesis.
Molecular and morphological evidence indicates that Pseudorhabdosynochus lantauensis (Monogenea: Diplectanidae) represents two species
Authors: WU X. Y. , CHILTON N. B. , ZHU X. Q. , XIE M. Q. , LI A. X.
Published: May 2005

Sequences of the first internal transcribed spacer (ITS-1) and the D1-D3 domains of the large subunit (LSU) of the ribosomal DNA (rDNA) were determined for multiple specimens of 4 operational taxonomic units (OTUs) of the monogenean, Pseudorhabdosynochus lantauensis. OTUs were defined based on their collecting localities, host and/or morphological characteristics. All P. lantauensis specimens of one group (OTUs 1 and 3) differed in their sequences of the ITS-1 and partial LSU rDNA when compared with specimens of a second group (OTUs 2 and 4) by 12% and 2%, respectively. Results of the phylogenetic analyses of the LSU rDNA sequence data showed total (100%) bootstrap support for the separation of P. lantauensis into 2 distinct clades. At least 11 of the 18 nucleotide differences in the LSU sequence between the two P. lantauensis clades were derived (i.e. autapomorphic) characters when the morphologically distinct species, P. epinepheli and P. coioidesis, were used as outgroups. Furthermore, there were several autapomorphic character states for each P. lantauensis clade. This provides sufficient evidence to reject the null hypothesis that P. lantauensis represents a single species. Morphological and morphometric differences between these two clades provided additional strong support for the separation of P. lantauensis into two species. These two parasite species were found to co-exist on one of the two species of serranid fish (i.e. Epinephelus coioides) examined in the South China Sea (Guangdong Province, China).
Complete sequence and structure of the mitochondrial genome of the human tapeworm,Taenia asiatica(Platyhelminthes; Cestoda)
Authors: JEON H. K. , LEE K. H. , KIM K. H. , HWANG U. W. , EOM K. S.
Published: May 2005

The completeTaenia asiaticamitochondrial genome was amplified by long extension polymerase chain reaction (long PCR) to yield overlapping fragments that were then completely sequenced. The whole mitochondrial genome was 13703 bp long and contained 12 protein-encoding, 2 ribosomal RNA (small and large subunits), 22 transfer RNA genes and a short non-coding region. Thus, its gene contents are like those typically found in metazoan animal mitochondrial genomes (apart from the absence ofatp8). All the genes were transcribed from the same strand. The 3′ end 34 bp region ofnad4Loverlapped with the 5′ end portion ofnad4. The tRNA genes were 61–69 bp long, and the secondary structures of 18 tRNAs had typical clover-leaf shapes with paired DHU arms. However,trnC,trnS1,trnS2andtrnRhad unpaired DHU arms that were 7–12 bp in length. The tRNAs that transferred serine lacked a DHU arm, as is also observed in a number of parasitic platyhelminths and metazoans. However, the trematodetrnRs have paired DHU arms. TheT. asiaticamtDNA non-coding region was like that in other cestodes since it was composed of a short non-coding region of 72 nucleotides and a long non-coding region of 176 nucleotides separated by atrnL1/,trnS2/,trnL2/,trnR/,nad5gene cluster. The sequences of thecox1genes betweenT. asiaticaandT. saginatadiffer by 4·6%, while theT. asiatica cobgene differs by 4·1% and 12·9% from thecobgenes ofT. saginataandT. solium, respectively. In conclusion, theT. asiaticamitocondrial genome should provide a resource for comparative mitochondrial genomics and systematic studies of parasitic cestodes.
Host specificity and the probability of discovering species of helminth parasites
Authors: POULIN R. , MOUILLOT D.
Published: May 2005

Different animal species have different probabilities of being discovered and described by scientists, and these probabilities are determined to a large extent by the biological characteristics of these species. For instance, species with broader geographical ranges are more likely to be encountered by collectors than species with restricted distributions; indeed, the size of the geographical range is often the best predictor of a species' date of description. For parasitic organisms, host specificity may be similarly linked to the probability of a species being found. Here, using data on 170 helminth species parasitic in freshwater fishes, we show that host specificity is associated with the year in which the helminths were described. Helminths that exploit more host species, and to a lesser degree those that exploit a broader taxonomic range of host species, tend to be discovered earlier than the more host-specific helminths. This pattern was observed across all helminth species, as well as within the different helminth taxa (trematodes, cestodes, nematodes and acanthocephalans). Our results demonstrate that the parasite species known at any given point in time are not a random subset of existing species, but rather a biased subset with respect to the parasites' biological properties.
Trematode infection correlates with shell shape and defence morphology in a freshwater snail
Authors: LEVRI E. P. , DILLARD J. , MARTIN T.
Published: May 2005

Parasitism often influences the phenotype of individuals. Many of the resulting changes are due to changes in resource allocation that come with infection. Here we examine the effect of a trematode parasite on the shape and defence morphology of a New Zealand freshwater snail, Potamopyrgus antipodarum. The trematode Microphallus sp. asexually produces hundreds of metacercarial cysts in the snail. The length, width and 2-dimensional area of each snail were measured. Snails were also assessed for their degree of spininess. Snails were dissected to determine gender, brooding condition and parasitism. Snails infected with Microphallus sp. were found to be significantly less spiny than uninfected snails. Microphallus-infected snails were also found to have a significantly greater width to length ratio at larger sizes than their uninfected counterparts. These trends could be explained in at least 3 ways. (1) Infection causes the snails to not produce spines and to become wider. (2) Spiny and narrower snails are more likely to die when they become infected. (3) Spiny and narrower snails are more resistant to infection. The changes in phenotype observed are unlikely to be adaptive for either the host or parasite and probably represent physiological by-products of the host-parasite relationship.
Body height, body mass index, waist-hip ratio, fluctuating asymmetry and second to fourth digit ratio in subjects with latent toxoplasmosis
Authors: FLEGR J. , HRŬSKOVÁ M. , HODNÝ Z. , NOVOTNÁ M. , HANUšOVÁ J.
Published: May 2005

Between 20% and 60% of the population of most countries are infected with the protozoanToxoplasma gondii. Subjects with clinically asymptomatic life-long latent toxoplasmosis differ from those who areToxoplasmafree in several behavioural parameters. Case-control studies cannot decide whether these differences already existed before infection or whether they were induced by the presence ofToxoplasmain the brain of infected hosts. Here we searched for such morphological differences betweenToxoplasma-infected andToxoplasma-free subjects that could be induced by the parasite (body weight, body height, body mass index, waist-hip ratio), or could rather correlate with their natural resistance to parasitic infection (fluctuating asymmetry, 2D[ratio ]4D ratio). We foundToxoplasma-infected men to be taller andToxoplasma-infected men and women to have lower 2D[ratio ]4D ratios previously reported to be associated with higher pre-natal testosterone levels. The 2D[ratio ]4D ratio negatively correlated with the level of specific anti-Toxoplasmaantibodies inToxoplasma-free subjects. These results suggest that some of the observed differences between infected and non-infected subjects may have existed before infection and could be caused by the lower natural resistance toToxoplasmainfection in subjects with higher pre-natal testosterone levels.
Content-based support for Persian learners of English
Authors: MIRZAIEAN VAHID , RAMSAY ALLAN
Published: May 2005

People learning a new language have problems with various
aspects of the language they want to learn – with its grammar, with its pronunciation, with its morphology... CALL tools have
been provided for most of these linguistic levels, but comparatively little has been done about helping students with problems of
meaning. We will argue that language technology is now mature enough to support tools that address at least some semantic issues,
and we will describe a tool that attempts to provide appropriate support for a specific class of learners.