bluuebunny/crossref_metadata_2025 huggingface dataset:
New method for the detection of intraperitoneal free air by sonography: Scissors maneuver
Authors: Karahan Okkes Ibrahim , Kurt Alibekir , Yikilmaz Ali , Kahriman Guven
Published: September 2004

Purpose

This study was conducted to investigate the diagnostic value of a new sonographic technique for the detection of intraabdominal free air.

Methods

Seventy‐two patients with a suspected gastrointestinal tract perforation were included in the study and prospectively evaluated by sonography and abdominal and chest radiography for the detection of intraperitoneal free air. A new sonographic technique (the scissors maneuver) was used to detect intraperitoneal free air superficial to the liver; the maneuver consists of applying and then releasing slight pressure onto the abdominal wall with the caudal part of a parasagittaly oriented linear‐array probe. The results of the imaging studies were correlated with surgical findings when possible.

Results

Sixteen patients had a surgically proven gastrointestinal tract perforation causing pneumoperitoneum. Sonography and radiography each showed pneumoperitoneum in 15 patients, with 1 false‐negative result for each modality. The sensitivity and specificity values of sonography and radiography were identical; sensitivity was 94% and specificity was 100% for both imaging modalities. The scissors maneuver was positive in all patients with sonographically detected pneumoperitoneum.

Conclusions

Sonography is an effective tool in the diagnosis of pneumoperitoneum, with sensitivity and specificity equal to those of radiography. The scissors maneuver may be a useful adjunct for improving the diagnostic yield of sonography. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:381–385, 2004
Neurogenic and non‐neurogenic placodes in ascidians
Authors: Manni Lucia , Lane Nancy J. , Joly Jean‐Stéphane , Gasparini Fabio , Tiozzo Stefano , Caicci Federico , Zaniolo Giovanna , Burighel Paolo
Published: September 2004

The late differentiation of the ectodermal layer is analysed in the ascidians Ciona intestinalis and Botryllus schlosseri, by means of light and electron microscopy, in order to verify the possible presence of placodal structures. Cranial placodes, ectodermal regions giving rise to nonepidermal cell types, are classically found exclusively in vertebrates; however, data are accumulating to demonstrate that the nonvertebrate chordates possess both the genetic machinery involved in placode differentiation, and ectodermal structures that are possible homologues of vertebrate placodes. Here, the term “placode” is used in a broad sense and defines thickenings of the ectodermal layer that can exhibit an interruption of the basal lamina where cells delaminate, and so are able to acquire a nonepidermal fate. A number of neurogenic placodes, ones capable of producing neurons, have been recognised; their derivatives have been analysed and their possible homologies with vertebrate placodes are discussed. In particular, the stomodeal placode may be considered a multiple placode, being composed of different sorts of placodes: part of it, which differentiates hair cells, is discussed as homologous to the octavo‐lateralis placodes, while the remaining portion, giving rise to the ciliated duct of the neural gland, is considered homologous to the adenohypophyseal placode. The neurohypophyseal placode may include the homologues of the hypothalamus and vertebrate olfactory placode; the rostral placode, producing the sensorial papillae, may possibly be homologous to the placodes of the adhesive gland of vertebrates. J. Exp. Zool. (Mol. Dev. Evol.) 302B:1–22, 2004. © 2004 Wiley‐Liss, Inc.
A synthetic peptide containing loop 4 of nerve growth factor for targeted gene delivery
Authors: Zeng Jieming , Too Heng‐Phon , Ma Yuexia , Luo Elizabeth S. E. , Wang Shu
Published: September 2004

Background

Gene delivery vectors that restrict the expression of a therapeutic gene to a particular type of cells are critical to gene therapy in a complex structure, such as the central nervous system. We constructed a nonviral vector for targeted gene transfer to cells expressing nerve growth factor (NGF) receptor TrkA.

Methods and results

The vector was a synthetic chimeric peptide composed of a targeting moiety derived from NGF loop 4 and a DNA‐binding moiety of 10 lysine residues. The peptide activated signal transduction pathways of the NGF receptor TrkA in PC12 cells and supported the survival of the cells after serum deprivation. After forming complexes with plasmid DNA, the peptide dose‐dependently increased reporter gene expression in PC12 cells, which could be inhibited by excess NGF. The peptide‐mediated gene expression was not affected in PC12 cells by co‐incubation with a blocking antibody against the low‐affinity NGF receptor p75 and was significantly enhanced in NIH3T3 cells stably transfected with TrkA cDNA, suggesting the involvement of the high‐affinity NGF receptor TrkA without the participation of p75. Moreover, the peptide did not assist gene transfer in TrkA‐poor, but TrkB‐ and/or TrkC‐positive primary cerebellar granule neurons and primary cortical glial cells.

Conclusions

The chimeric peptide reported will be useful in gene delivery to and gene therapy of the nervous system and other tissues/organs with cells expressing TrkA. Copyright © 2004 John Wiley & Sons, Ltd.
Recovery of functional cytotoxic T lymphocytes during lamivudine therapy by acquiring multi‐specificity
Authors: Kondo Yasuteru , Asabe Shinichi , Kobayashi Koju , Shiina Masaaki , Niitsuma Hirofumi , Ueno Yoshiyuki , Kobayashi Tomoo , Shimosegawa Tooru
Published: September 2004

To characterize cytotoxic T lymphocytes (CTLs) that appeared in circulation during lamivudine therapy, we analyzed HBV‐specific CTLs using HLA‐A24 tetramer and HBcAg‐specific Th1 cells in patients receiving lamivudine therapy. Six patients (HLA‐A24+) with chronic hepatitis B, six patients (HLA‐A24−) with chronic hepatitis B, and six patients (HLA‐A24+) with chronic hepatitis C were studied. In addition to known CTL epitopes (C117 and P756), three epitopes were confirmed as CTL epitopes (C23, S89, S226) by chromium release assay and by staining intracellular perforin. CTLs specific for P756 were most frequently found at pre‐treatment. During lamivudine therapy, increase in the frequencies of HLA‐tetramer+ cells was found for C117, S89, and S226. Recovery of CTLs was observed earlier in patients with HBeAg−/anti‐HBe+ compared with those with HBeAg+/anti‐HBe−. HBcAg‐specific Th1 cells did not increase significantly up to 8 weeks. T cell lines from patients with chronic hepatitis B had a lower level of proliferation (0‐ to 24.9‐fold expansion by in vitro stimulation) and a higher ability to produce interferon‐γ (0–84% except for S89), while perforin‐positive cells showed low frequencies (0–50% except for S89). In conclusion, these results suggest that lamivudine therapy induces mainly CTLs that were less frequent before the therapy. Since recovered CTLs maintained the ability to produce interferon‐γ in response to peptides, these CTLs apparently contribute to the efficacy of lamivudine therapy in patients with hepatitis B. J. Med. Virol. 74:425–433, 2004. © 2004 Wiley‐Liss, Inc.
Isolation and characterisation of poliovirus mutants resistant to heating at 50°c for 30 min
Authors: Shiomi Hiroshi , Urasawa Tomoko , Urasawa Shozo , Kobayashi Nobumichi , Abe Shibobu , Taniguchi Koki
Published: September 2004

Poliovirus is heat‐labile; on heating at 50°C for 30 min its infectivity decreases drastically and its antigenicity reverts from N to H. However, mutants resistant to heating at 50°C for 30 min from the Sabin 1 and 2 viruses were isolated by repeating the process of incubation of the virus stock at 50°C for 30 min and multiplication of the remaining virus in a cell culture. The isolated mutants were stable genetically, and maintained the rct and d markers of the parent virus. On electron microscopical examination, the mutants were observed to retain the intact morphology after being heated at 50°C for 30 min, while the parent virus was converted to empty particles devoid of RNA under the same conditions. On determination of the nucleotide sequence of the P1 region, a single nucleotide sequence substitution was detected at nucleotide no. 2741, resulting in an amino acid change from valine to alanine at the 87th position of VP1. This amino acid might be associated with the heat‐resistance of the mutants. Furthermore, it was found that the thermostable mutants obtained in this study, which are resistant to “high” temperature (50°C) for a short time (30 min), were not stable against heating at the ambient temperature (37°C) for a long time (5 or 7 days). This suggests that the inactivation at high temperature for a short time and that at ambient temperature for a long time involve different mechanisms. J. Med. Virol. 74:484–491, 2004. © 2004 Wiley‐Liss, Inc.
Hepatitis E in the south west of France in individuals who have never visited an endemic area
Authors: Mansuy Jean Michel , Peron Jean Marie , Abravanel Florence , Poirson Hélène , Dubois Martine , Miedouge Marcel , Vischi Françoise , Alric Laurent , Vinel Jean Pierre , Izopet Jacques
Published: September 2004

A total of 431 consecutive patients from the Midi Pyrenees area with acute hepatitis with unknown etiology in 2001–2002 were tested for the presence of immunoglobulin G‐class (IgG) anti‐hepatitis E virus (HEV) antibodies. Forty‐six (10.7%) had anti‐HEV IgG, and the results were questionable for a further 17 (3.9%). Real time PCR based on TaqMan detection was used to identify HEV genome fragments in the serum of patients with positive or questionable anti‐HEV serology. HEV RNA was found in 25.4% of cases. All amplification products were sequenced and analyzed. Phylogenetic analysis revealed that all the strains were genotype 3. In conclusion, virological and epidemiological data indicate that genotype 3 viruses are circulating in the south west part of France (Midi‐Pyrenees) in patients with acute hepatitis and who have not visited recently areas in which HEV is endemic. J. Med. Virol. 74:419–424, 2004. © 2004 Wiley‐Liss, Inc.
Simplified equivalent‐circuit modelling for decoupled and partial decoupled methods in semiconductor device simulation
Authors: Dai Jing‐Fu , Chang Chia‐Cherng , Lee Jia‐Wen , Li Szu‐Ju , Tsai Yao‐Tsung
Published: September 2004

In this paper, we study the decoupled method which requires less memory on semiconductor device simulation. The decoupled method decouples the three equivalent circuits of semiconductor and solves them sequentially. The three equivalent circuits are formed by formulating the three partial differential equations that describe the electrical behaviour of semiconductor. Since the decoupled method solves one equation in each stage, the decoupled method uses one‐ninth memory space of the coupled method. When decoupling the three equivalent circuits, the decoupled method yields a boundary condition limitation. In order to overcome the limitation, we propose a compromising partial decoupled method which has complete boundary condition and requires four‐ninth memory space of the coupled method. The three methods are compared for computational efficiency and accuracy in the simulation of BJT. The simulation results are identical. Copyright © 2004 John Wiley & Sons, Ltd.
Wide‐band modelling of CMOS interconnections and voiding damages with the lumped element LE‐FDTD method
Authors: Alimenti F. , Impronta M. , Scorzoni A. , Roselli L.
Published: September 2004

This paper illustrates the application of a lumped element‐finite difference time domain (LE‐FDTD) simulator to the wide‐band modelling of CMOS interconnections. To achieve very accurate results the short‐open calibration (SOC) technique has been adopted. Specific parameters of a CMOS interconnection laterally screened by a stack of metal vias have been extracted in the two cases of an unperturbed and a purposely damaged metal line. The behaviour of void‐like defects in the metal line has been also studied using the fully three‐dimensional capabilities of the simulator. It has been demonstrated that, at least in the simulated cases, only the specific resistance is affected by damaging. Copyright © 2004 John Wiley & Sons, Ltd.
Comparison between line and surface integral formulations of the hybrid mode‐matching/two‐dimensional finite element method
Authors: Crinó Vincenzo , Tomassoni Cristiano , Mongiardo Mauro
Published: September 2004

The hybrid mode‐matching/two‐dimensional‐finite‐element (MM/FEM2D) technique has been proposed for the analysis of discontinuities with waveguides of arbitrary cross section; this technique combines the computational efficiency of modal analysis with the versatility and flexibility of the FEM approach.

In this paper, we present in detail a surface‐integrals and a line‐integrals formulation of the hybrid MM/FEM2D technique, in case the ‘Standard Formulation’ is used as FEM2D formulation. Such formulations allow computing analytically both the normalization and the coupling integrals. Furthermore, we compare the accuracy obtained by using the line‐integrals and the corresponding surface‐integrals formulation. To these aims we present several numerical results. Copyright © 2004 John Wiley & Sons, Ltd.
Vibrational spectroscopic studies, conformations and ab initio calculations of n‐propyltrichlorosilane
Authors: Aleksa V. , Klaeboe P. , Nielsen C. J. , Guirgis G. A. , Durig J. R.
Published: September 2004

Infrared spectra of n‐propyltrichlorosilane (CH3CH2CH2SiCl3) were obtained in the vapour, amorphous and crystalline solid phases in the range 4000–50 cm−1. Additional spectra in argon and nitrogen matrices at 5 K were recorded before and after annealing to 20–36 K. Raman spectra of the compound as a liquid were recorded at various temperatures between 300 and 153 K and spectra of the amorphous and crystalline solids were obtained. The spectra revealed the existence of two conformers (anti and gauche) in the fluid phases and in the matrices. When the vapour was shock‐frozen on a cold‐finger at 78 K and subsequently annealed to 120–130 K, 10 Raman bands and eight IR bands of the liquid were reduced in intensity in the amorphous phase and vanished in the crystal. Frequent intensity variations were observed in the infrared spectra of argon and nitrogen matrices before and after annealing. These spectra revealed the existence of one conformer (anti) in the crystal. From intensity variations of four independent pairs of anti and gauche bands in the Raman spectra between 300 and 150 K, an average value ΔH°(gauche–anti) = 4.6 ± 0.3 kJ mol−1 was obtained in the liquid. Annealing experiments on n‐propyltrichlorosilane in the matrices demonstrate that the gauche bands vanish after annealing, revealing that the anti conformer has the lower energy. The spectra of both conformers were interpreted in detail. Ab initio and DFT calculations gave optimized geometries, infrared and Raman intensities and scaled vibrational wavenumbers for the anti and gauche conformers. The conformational energy difference derived was 7.6 and 6.4 kJ mol−1 for the HF/6–311G* and B3LYP/6–311G* basis sets, respectively, with anti being the low‐energy conformer. Copyright © 2004 John Wiley & Sons, Ltd.
Raman spectroscopy of a family of organoaluminum compounds
Authors: Beard Bruce C.
Published: September 2004

Raman spectroscopy was used for the study of a sequential family of organoaluminum compounds. The compounds were prepared by redistribution reactions between trimethylaluminum and tri‐tert‐butoxyaluminum, leading to molecules with all possible ligand combinations. In the liquid phase, these compounds exist as dimers linked by bridging ligands involved in three‐center bonding. Terminal groups are exchanged first followed by the bridging groups. Characteristic group wavenumbers and molecular modes were compared at every stage of redistribution in the spectral range of 1100–150 cm−1. Copyright © 2004 John Wiley & Sons, Ltd.
Corrosion inhibition approach of oil production systems in offshore oilfields
Authors: Zhao L. , Teng H. K. , Yang Y. S. , Tan X.
Published: September 2004

Synthesis and modification of imidazoline were carried out based on review of the corrosion inhibitor development and application for oilfields. A series of imidazoline compounds were synthesised through the solvent dewatering and vacuum dewatering methods. After reaction of imidazoline with ethane oxide, the produced compound was used to react with halogen hydrocarbon and polyphosphoric acid respectively. Finally an agent with performance of corrosion‐inhibition, sterilisation and anti‐scaling was obtained. The structures of the compounds were characterised by the Fourier transformation infrared spectrum. The relationships between corrosion inhibition effectiveness of the compounds and their structures were investigated so as to determine the structure of a novel corrosion inhibitor. The selected corrosion inhibitor was evaluated by a series of experiments to understand the characteristics of imidazoline derivative and some major factors associated with oil production in the oilfields of China. The experimental results showed that this corrosion inhibitor has outstanding performance of corrosion inhibition and sterilization, and is suitable for corrosion inhibition of the oil abstraction systems with high water‐content in the offshore oilfields.
Poly(4‐hexyl‐1,2,4‐triazole‐4H): An Electron Semiconducting Analogue to Regioregular Poly(hexylthiophene)
Authors: Janietz Silvia , Barche Jens , Wedel Armin , Sainova Dessislava
Published: September 2004

Summary: For the development of n‐channel field‐effect transistors it is indispensable to look for semiconducting polymers with electrons as majority charge carriers (n‐type). In addition high electron mobility values are of significant advantage in these compounds. Polymers with electron transporting properties have been rarely investigated. Main chain polymers with strong acceptor units like 1,2,4‐triazoles‐4H are potential candidates for electron transporting materials in electronic devices. Therefore, a synthetic pathway leading to an organo‐soluble polymer consisting only of 4‐hexyl‐1,2,4‐triazole‐4H units in the main chain is presented in this work. We will report the synthesis using modified classical polycondensation. The chemical and electronic properties of the polytriazole have been investigated in detail. The material has been used to prepare “electron‐only” devices for the calculation of the electron mobility.

The suggested chemical structure of poly(4‐hexyl‐1,2,4‐triazole‐4H) (PHTA).

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The suggested chemical structure of poly(4‐hexyl‐1,2,4‐triazole‐4H) (PHTA).
Influence of Mid‐Chain Radicals on Acrylate Free Radical Polymerization: Effect of Ester Alkyl Group
Authors: Sato Eriko , Emoto Tetsuya , Zetterlund Per B. , Yamada Bunichiro
Published: September 2004

Summary: The benzene solution polymerizations of tert‐butyl acrylate (tBA) and 2‐ethylhexyl acrylate (EHA) have been investigated with respect to the effects of mid‐chain radicals (MCRs) on the rate of polymerization, the total radical concentration, the apparent rate coefficients for propagation, termination, and β‐fragmentation, the contents of unsaturated end groups and branching, and the molecular weight distribution. The EHA polymerization involves a considerably higher concentration of MCR and is more significantly affected by MCR than the tBA polymerization. The MCR content as estimated by electron paramagnetic resonance (EPR) spectroscopy during photosensitized EHA polymerization was as high as 70% of the total radical concentration at 25 °C. However, no 1H and 13C NMR resonances due to unsaturated ends and branching, respectively, were detected for the poly(EHA) obtained at 25 °C. These findings indicate that a high MCR content does not directly correspond to significant MCR effects on the polymer structure. The rate constants for mutual reaction ($k'_{\rm t}$) and β‐fragmentation (kf) of MCR were estimated for the two assumed cases where MCR was consumed solely by (i) mutual reaction, and (ii) β‐fragmentation, based on the after‐effect of the photosensitized EHA polymerization monitored by EPR spectroscopy at 25 °C; $k'_{\rm t}$ = 3.5 × 103 L · mol · s−1 and kf = 4.2 × 10−2 s−1. These rate coefficients were compared with those for reactions of structurally similar radicals.

Reaction pathways of MCRs.

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Reaction pathways of MCRs.
Isothermal Crystallization of Poly(ε‐caprolactone) in Blend with Poly(styrene‐co‐acrylonitrile): Influence of Phase Separation Process
Authors: Madbouly Samy A. , Ougizawa Toshiaki
Published: September 2004

Summary: The isothermal crystallization process of poly(ε‐caprolactone) (PCL) and its blend with styrene‐acrylonitrile random copolymer containing 27.5 wt.‐% acrylonitrile has been investigated as a function of crystallization and melting temperatures for different melting times in the vicinity of the lowest critical solution temperature (LCST)‐type phase diagram using DSC. The obtained results showed that the isothermal crystallization kinetics from the melt of PCL in the blend was greatly affected by the presence of SAN. For a given crystallization temperature, the crystallization half time (t0.5) in the case of PCL/SAN = 80/20 blend was much longer than the corresponding value for pure PCL. This depression in the crystallization kinetics of PCL in the blend was mainly attributed to the favorable interaction between the two components and the reduction in chain mobility as a result of increasing the Tg by adding the amorphous component (SAN). In addition, the value of t0.5 was found to be independent of the melting temperature (Tm) and melting time for pure PCL. The isothermal crystallization kinetics for samples that were crystallized after decomposition into different stages of phase separation were also investigated. A major acceleration in the crystallization kinetics was observed isothermally for the samples that had undergone phase separation in the early and middle stages. The isothermal crystallization kinetics was also analyzed based on the Avrami approach. Although the crystallization kinetics was accelerated to a great extent by the liquid‐liquid phase separation, no change in the crystallization mechanism could be predicted. Furthermore, the phase separation process of PCL/SAN blend has been studied indirectly by following the variation in t0.5 at different melting temperatures and melting times above the LCST phase diagram.

Melting temperature, Tm, dependence of crystallization half time, t0.5.

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Melting temperature, Tm, dependence of crystallization half time, t0.5.
Electrospinning of Chitosan
Authors: Ohkawa Kousaku , Cha Dongil , Kim Hakyong , Nishida Ayako , Yamamoto Hiroyuki
Published: September 2004

Summary: An electrospun nonwoven fabric of a cationic polysaccharide, chitosan, was successfully prepared. The present study focuses on the effect of the electrospinning solvent and the chitosan concentration on the morphology of the resulting nonwoven fabrics. The solvents tested were dilute hydrochloric acid, acetic acid, neat formic acid and trifluoroacetic acid. As the chitosan concentration was increased, the morphology of the deposition on the collector changed from spherical beads to interconnected fibrous networks. The addition of dichloromethane to the chitosan‐TFA solution improved the homogeneity of the electrospun chitosan fiber. Under optimized conditions, homogenous (not interconnected) chitosan fibers with a mean diameter of 330 nm were prepared.

Effects of the coexisting dichloromethane (MC) in the prespun chitosan‐TFA solution on the morphology of the electrospun chitosan fibers. The volume ratio of TFA:MC was 70:30 (×5 000).

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Effects of the coexisting dichloromethane (MC) in the prespun chitosan‐TFA solution on the morphology of the electrospun chitosan fibers. The volume ratio of TFA:MC was 70:30 (×5 000).
Low‐Density Polyethylene Superhydrophobic Surface by Control of Its Crystallization Behavior
Authors: Lu Xiaoying , Zhang Changchun , Han Yanchun
Published: September 2004

Summary: A simple and inexpensive method for forming a low‐density polyethylene (LDPE) superhydrophobic surface by controlling the crystallization behavior of LDPE by adjusting the crystallization time and nucleation rate has been proposed. The resulting porous surface, with hierarchical micro‐ and nanostructures on the beautiful floral designs, has a water contact angle of 173.0° ± 2.5°.

A highly porous surface created by adding nonsolvent (cyclohexanone) followed by evaporation of the LDPE in a vacuum at 25 °C (left, inset shows corresponding water contact angle). Nanostructures on the florallike crystal structures (right).

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A highly porous surface created by adding nonsolvent (cyclohexanone) followed by evaporation of the LDPE in a vacuum at 25 °C (left, inset shows corresponding water contact angle). Nanostructures on the florallike crystal structures (right).
Microdeformation in Heterogeneous Polymers, Revealed by Electron Microscopy
Authors: Plummer Christopher J.G. , Béguelin Philippe , Grein Chrystelle , Gensler Rudolph , Dupuits Laure , Gaillard Cedric , Stadelmann Pierre , Kausch Hans‐Henning , Månson Jan‐Anders E.
Published: September 2004

Recent investigations of the tensile fracture behaviour of representative glassy and semicrystalline impact‐resistant polymers are reviewed, with emphasis on the microdeformation behaviour as revealed by electron microscopy of sections from bulk specimens, where the crack‐tip damage zone has been embedded and/or stained under load, and on thin films deformed in situ. The insight that such techniques have provided into the toughening mechanisms is discussed.
Morphology and Properties of Particulate Filled Polymers
Authors: Pukánszky Béla , Móczó János
Published: September 2004

Although the structure of particulate filled polymers is usually thought to be very simple, often structure related phenomena determine their properties. Segregation occurs only when long flow paths and large particles are used in production. The occurrence and extent of aggregation depend on the relative magnitude of attractive and separating forces, which prevail during the homogenization of the composite; the balance of adhesive and shear forces determines structure. Fillers of small particle size always aggregate, usually leading to decreased strength and especially low impact resistance. Anisotropic particles (talc, mica, short fibers) are orientated during processing. ESR is a relatively simple technique for the estimation of orientation and orientation distribution, which are determined by processing conditions, i.e. flow pattern, shear conditions, mold filling rates, cooling conditions, etc. The orientation of the particles strongly affects composite stiffness and strength. In practice, often several factors simultaneously influence the properties of products prepared from particulate filled polymers. Separation of the effects of the influencing factors is difficult, although such knowledge would help to control composite properties. The structure and properties of injection and compression moulded PP composites containing CaCO3 or talc differs considerably from each other. The aggregation of CaCO3, the nucleating effect and the orientation of talc affect product properties. The latter are also influenced by the skin‐core structure developing during injection molding as well as by the orientation of the polymer. An example is discussed in this paper, which facilitates the identification of the effect of these factors with the help of a simple model and indicates a way in which product properties can be controlled.
Morphology and Properties of Poly(oxymethylene) Engineering Plastics
Authors: Sukhanova Tatiana , Bershtein Vladimir , Keating Mimi , Matveeva Galina , Vylegzhanina Milana , Egorov Victor , Peschanskaya Nina , Yakushev Pavel , Flexman Edmund , Greulich Stefan , Sauer Bryan , Schodt Kathleen
Published: September 2004

Comparative WAXD/SAXS/SEM/DSC structural studies of a series of semi‐crystalline poly(oxymethylene) (POM) engineering plastics, including the commercial products, homopolymer Delrin® and typical poly(oxymethylene‐co‐oxyethylene)s, and a few lab‐made POM compositions, were performed. The latter differed in their content of functional additives (present in low concentrations) and POM molecular weight characteristics. In parallel, their densities, thermal behavior/laser‐interferometric creep rate spectra (DSC/CRS) at 20‐180 °C, as well as long‐term creep resistance (LTCR) at 20 °C were studied. It has been found that introducing the nucleating agents and oxyethylene units resulted in formation of more fine spherulitic or practically non‐spherulitic structure with close‐ or loose‐packed lamellar stacks. The presence of both “thick” (5‐10 nm) and “thin” (1.5‐3 nm) lamellae in the weight ratio of ∼3:1 was shown in all cases. Close values of real POM crystallinities, not exceeding 50%, were obtained by WAXD and DSC. A predominant role of “straightened out” or slightly bent tie chains in disordered layers of isotropic POMs was presumed, resulting in segmental dynamics differently constrained by crystallites (DSC/CRS data). As a result, certain morphology ‐ density ‐ creep resistance correlations were found.
The Use of Pressure‐Volume‐Temperature Measurements in Polymer Science
Authors: Hess Michael
Published: September 2004

The importance of the knowledge of thermodynamic parameters from p‐V‐T experiments is shown in different fields of polymer science with special emphasis on determination of the phase behaviour of polymer systems.
Autosomal recessive primary generalized dystonia in two siblings from a consanguineous family
Authors: Moretti Paolo , Hedera Peter , Wald John , Fink John
Published: September 2004

We describe the clinical features of a brother and sister with non–dopa‐responsive, childhood‐onset, generalized dystonia. The children were born to consanguineous parents, had no family history of neurologic disease, no evidence of structural or metabolic causes of dystonia, and negative testing for the GAG946 deletion mutation in the DYT1 gene. This report supports the existence of a generalized type of dystonia with autosomal recessive inheritance (DYT2). © 2004 Movement Disorder Society
The substitution pattern of anthocyanidins affects different cellular signaling cascades regulating cell proliferation
Authors: Marko Doris , Puppel Nicole , Tjaden Zeina , Jakobs Sandra , Pahlke Gudrun
Published: September 2004

The aglycons of the most abundant anthocyanins in food, cyanidin (cy) and delphinidin (del), represent potent inhibitors of the epidermal growth factor receptor (EGFR). Structure‐activity studies show that the presence of vicinal hydroxy substituents at the phenyl ring at the 2‐position (B‐ring) is crucial for target interaction. The presence of a single hydroxy group or introduction of methoxy substituents at the B‐ring results in a substantial loss of inhibitory properties. However, biological activity is not exclusively limited to compounds bearing vicinal hydroxy groups. A contradictory structure‐activity relationship is observed for the inhibition of cAMP‐specific phosphodiesterases (PDEs). Of the anthocyanidins tested, malvidin, bearing methoxy substituents in the 3′‐ and 5′‐positions, most effectively inhibited cAMP hydrolysis. The absence of methoxy groups and/or replacement by hydroxy substituents was found to strongly diminish PDE‐inhibitory properties. We found that either effective EGFR inhibition or effective PDE inhibition is required to achieve a shut‐down of the central mitogen‐activated protein kinase (MAPK) pathway, a signaling cascade crucial for the regulation of cell growth. This is consistent with the finding that efficient reduction of cell growth is limited to anthocyanidins that are potent EGFR‐ or PDE‐inhibitors including cy and del or malvidin (mv), respectively. In summary, depending on the substitution pattern at the B‐ring, anthocyanidins interfere with different signaling cascades involved in the regulation of cell growth.
Broadband rectangular‐to‐ridge‐to‐T‐septum waveguide transformers
Authors: Labay Vladimir A. , Bornemann Jens
Published: September 2004

Broadband transformers from rectangular to T‐septum waveguides are presented. By utilizing both ridge and T‐septum waveguide sections in the transformer design, the thicknesses of the ridge and the T‐septa can be kept constant, which simplifies fabrication. The three‐ and four‐section designs achieve relative bandwidths of 57% and 72%, respectively. Both designs are verified through computations with commercially available field solver software. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 183–185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20414
Frequency‐domain modal analysis of nonuniformly coupled transmission‐line structures
Authors: Brandão Faria J. A.
Published: September 2004

The analysis of n‐coupled transmission lines with nonuniform cross‐section is often necessary in the design and simulation of high‐speed integrated circuits. A new modal analysis technique is presented, illustrating how a 2n‐port coupled nonuniform line structure can be broken down into a set of n uncoupled 2‐port nonuniform lines. Modal propagation parameters and modal transformation matrices are retrieved from the entries of the ABCD‐matrix representation of the n‐coupled line structure. An application concerning a tapered transmission‐line system typically found in chip‐carrier interconnections is provided as an example. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 186–189, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20415
Small microstrip antennas for mobile communications
Authors: Wang Chien‐Jen , Tsai Wen‐Tsai
Published: September 2004

Three microstrip miniaturized meanderline antennas for mobile communications are presented in this paper. Two‐arm meanderline antennas, one with a patch and one with a rectangular loop, are fabricated and tested. The advantages of the antennas are the lower circuit cost, light antenna weight, short process time, a minimum number of via holes and simplified mechanical construction. In our experiments, comparisons of the radiated power and return loss of the three topologies of the meander‐line antenna are presented. The loading effect of the outside environments surrounding the meander‐line antennas is also discussed. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 207–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20420
High‐efficiency planar slot‐array antenna with a single waveguide‐fed cavity‐backed subarray
Authors: Lee Byungje , Jung Kangjae , Yang Sung‐Hyun
Published: September 2004

A cavity‐backed slot antenna array using a single waveguide‐fed subarray is proposed to reduce feed‐line loss, increase radiation efficiency, and make the feed network simple. A subarray consists of 2 × 4 slot elements backed by a single cavity. By proper choice of dimensions, it is shown that the proposed antenna has the characteristics of high radiation efficiency and broad frequency bandwidth. The antenna characteristics for the array antenna with 256 elements are measured in the Ku‐band. A single cavity‐backed subarray has a gain of 18 dBi. The gain of the total antenna array (256 elements) is more than 33 dBi. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 228–231, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20426
Novel microstrip bandpass filter with transmission zeros in the stopband
Authors: Jianxin Chen , Mengxia Yu , Jun Xu , Quan Xue
Published: September 2004

This paper describes a novel microstrip bandpass filter with transmission zeros in the stopband, low insertion loss in the passband, and compact size, which is achieved by giving two or three transmission paths to the input signals. The demonstrated filters are designed, fabricated, and tested. Theoretical and experimental results are presented. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 238–240, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20429
Analysis of microwave tomography systems using the wire‐volume integral equations method
Authors: Hu Jin‐Lin , Wu Zhipeng , McCann Hugh , Davis Lionel Edward , Fontes Adolfo
Published: September 2004

A numerical scheme to analyse the forward problem in microwave tomography systems is introduced in this paper. Wire‐volume electric‐field integral equations are given to describe the electromagnetic environment in microwave tomography systems. The 1D triangular function and the 3D volumetric rooftop function are chosen as the basis functions to approximate the unknown electric current in the antennas and electric flux density in the object. The bi‐conjugate gradient method is employed to solve the system of linear equations. A comparison of the measured results shows that this scheme is efficient for simulating microwave tomography systems. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 250–253, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20434
Brain development in autism: Early overgrowth followed by premature arrest of growth
Authors: Courchesne Eric
Published: September 2004

Due to the relatively late age of clinical diagnosis of autism, the early brain pathology of children with autism has remained largely unstudied. The increased use of retrospective measures such as head circumference, along with a surge of MRI studies of toddlers with autism, have opened a whole new area of research and discovery. Recent studies have now shown that abnormal brain overgrowth occurs during the first 2 years of life in children with autism. By 2–4 years of age, the most deviant overgrowth is in cerebral, cerebellar, and limbic structures that underlie higher‐order cognitive, social, emotional, and language functions. Excessive growth is followed by abnormally slow or arrested growth. Deviant brain growth in autism occurs at the very time when the formation of cerebral circuitry is at its most exuberant and vulnerable stage, and it may signal disruption of this process of circuit formation. The resulting aberrant connectivity and dysfunction may lead to the development of autistic behaviors. To discover the causes, neural substrates, early‐warning signs and effective treatments of autism, future research should focus on elucidating the neurobiological defects that underlie brain growth abnormalities in autism that appear during these critical first years of life. MRDD Research Reviews 2004;10:106–111. © 2004 Wiley‐Liss, Inc.
Serotonin in autism and pediatric epilepsies
Authors: Chugani Diane C.
Published: September 2004

Serotonergic abnormalities have been reported in both autism and epilepsy. This association may provide insights into underlying mechanisms of these disorders because serotonin plays an important neurotrophic role during brain development—and there is evidence for abnormal cortical development in both autism and some forms of epilepsy. This review explores the hypothesis that an early disturbance in the serotonin system affects cortical development and the development of thalamocortical innervation, and is a potential mechanism, common to autism and pediatric epilepsies associated with cortical dysplasia. An argument is made that cortical malformation leads to abnormalities of thalamocortical connectivity, and that serotonin plays a critical role in this process. Finally, a role for altered metabolism of the serotonin precursur, tryptophan, in both epilepsy and autism is discussed. MRDD Research Reviews 2004;10:112–116. © 2004 Wiley‐Liss, Inc.
AEDs and psychotropic drugs in children with autism and epilepsy
Authors: Tuchman Roberto
Published: September 2004

The efficacy of antiepileptic drugs (AEDs) and psychotropic medications in children with autism is limited to the treatment of seizures or to specific behaviors such as irritability, impulsivity, hyperactivity, repetitive behaviors, or aggression. The reliability and value of the available data—to determine the efficacy of these medications in autism—are limited by lack of controlled clinical trials, the small number of subjects, the heterogeneity of the population studied, and the brief duration of most drug trials. Indeed, few controlled clinical trials using AEDs in autism, with or without seizures, have been conducted. Because some AEDs also have a positive effect on mood, the benefits that children with autism sometimes obtain from these medications may not be due to the treatment of the abnormal electrical activity or the seizures per se but to an effect on common neuronal systems responsible for both behavior and epilepsy. The relationship between epilepsy and autism, and specifically the effects that abnormal electrical activity may have on the developing brain, may provide some valuable insights into the type of studies that are needed to help us understand the pathophysiology of autism. MRDD Research Reviews 2004;10:135–138. © 2004 Wiley‐Liss, Inc.
Dermatomyositis‐like syndrome and HMG‐CoA reductase inhibitor (statin) intake
Authors: Vasconcelos Olavo M. , Campbell William W.
Published: September 2004

A patient developed an adult‐onset dermatomyositis‐like syndrome characterized by skin rash and progressive proximal muscle weakness concurrent with the intake of simvastatin. Despite discontinuation of the statin, symptoms progressed and required conventional steroid therapy for remission. The association between statins and the development of a musculocutaneous syndrome closely resembling dermatomyositis in susceptible subjects is poorly understood and has been reported rarely. The purpose of this report is to provide additional support for this pathological association. Since the population receiving statins is large and rapidly growing, caregivers are urged to be alert regarding the early recognition and proper care of the spectrum of neuromuscular complications linked to statin intake. Muscle Nerve, 2004
Tissue oxygenation in sepsis; new insights from in vivo EPR
Authors: James Philip E. , Thomas Matthew P. , Jackson Simon K.
Published: September 2004

Nitric oxide (NO) is a key mediator in the maldistribution of oxygen by tissue and organ dysfunction observed in sepsis. Despite this, few techniques are capable of measuring these parameters directly in vivo. We describe here several techniques that have been developed by our group to address this directly by in vivo EPR in animal models of sepsis. Oxygen‐sensitive materials can be implanted or administered and report on local tissue pO2. Spin trapping of NO can simultaneously report on tissue NO content. Repeat measures of these parameters can be made directly from a defined tissue site, allowing development of new models and experiments to study the defects in tissue and organ function seen in sepsis. Copyright © 2004 John Wiley & Sons, Ltd.
Clinical applications of EPR: overview and perspectives
Authors: Swartz Harold M. , Khan Nadeem , Buckey Jay , Comi Richard , Gould Lisa , Grinberg Oleg , Hartford Alan , Hopf Harriet , Hou Huagang , Hug Eugen , Iwasaki Akinori , Lesniewski Piotr , Salikhov Ildar , Walczak Tadeusz
Published: September 2004

The development and use of in vivo techniques for strictly experimental applications in animals has been very successful, and these results now have made possible some very attractive potential clinical applications. The area with the most obvious immediate, effective and widespread clinical use is oximetry, where EPR almost uniquely can make repeated and accurate measurements of pO2 in tissues. Such measurements can provide clinicians with information that can impact directly on diagnosis and therapy, especially for oncology, peripheral vascular disease and wound healing. The other area of immediate and timely importance is the unique ability of in vivo EPR to measure clinically significant exposures to ionizing radiation ‘after‐the‐fact’, such as may occur due to accidents, terrorism or nuclear war. There are a number of other capabilities of in vivo EPR that also potentially could become extensively used in human subjects. In pharmacology the unique capabilities of in vivo EPR to detect and characterize free radicals could be applied to measure free radical intermediates from drugs and oxidative process. A closely related area of potential widespread applications is the use of EPR to measure nitric oxide. These often unique capabilities, combined with the sensitivity of EPR spectra to the immediate environment (e.g. pH, molecular motion, charge) have already resulted in some very productive applications in animals and these are likely to expand substantially in the near future. They should provide a continually developing base for extending clinical uses of in vivo EPR. The challenges for achieving full implementation include adapting the spectrometer for safe and comfortable measurements in human subjects, achieving sufficient sensitivity for measurements at the sites of the pathophysiological processes that are being measured, and establishing a consensus on the clinical value of the measurements. Copyright © 2004 John Wiley & Sons, Ltd.
Formal specification of SNMPv3 entities using action semantics
Authors: Duarte Jr. Elias P. , Musicante Martin A. , Furlan Diógenes Cogo
Published: September 2004

This work presents a formal description of the structure and behaviour of SNMPv3 entities. IETF documents describe the semantics of the Simple Network Management Protocol version 3 in an almost completely informal way. Our formal description is given using action semantics, a completely formal yet verbose framework for the specification of programming concepts. The purpose of our description is to specify management entities without ambiguities, contributing to a better understanding of the NMPv3 framework that may lead to automatic implementation and verification of agents and manager applications. Copyright © 2004 John Wiley & Sons, Ltd.
Energy conserving and dissipative time finite element schemes for N‐body stiff problems
Authors: Bui Q. V.
Published: September 2004

Petrov–Galerkin finite element method is adopted to develop a family of temporal integrators, which preserves the feature of energy conservation or numerical dissipation for non‐linear N‐body dynamical systems. This leads to an enhancement of numerical stability and the integrators may therefore offer some advantage for the numerical solution of stiff systems in long‐term simulations. Dynamically tuneable numerical integration is exploited to improve the accuracy of the time‐stepping schemes. Representative simulations for simple non‐linear systems show the performance of the schemes in controlling over or damping out unresolved high frequencies. Copyright © 2004 John Wiley & Sons, Ltd.
Compression of time‐generated matrices in two‐dimensional time‐domain elastodynamic BEM analysis
Authors: Soares D. , Mansur W. J.
Published: September 2004

This paper describes a new scheme to improve the efficiency of time‐domain BEM algorithms. The discussion is focused on the two‐dimensional elastodynamic formulation, however, the ideas presented apply equally to any step‐by‐step convolution based algorithm whose kernels decay with time increase. The algorithm presented interpolates the time‐domain matrices generated along the time‐stepping process, for time‐steps sufficiently far from the current time. Two interpolation procedures are considered here (a large number of alternative approaches is possible): Chebyshev–Lagrange polynomials and linear. A criterion to indicate the discrete time at which interpolation should start is proposed. Two numerical examples and conclusions are presented at the end of the paper. Copyright © 2004 John Wiley & Sons, Ltd.