bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of a single‐acquisition imaging sequence for oxygen‐sensitive 3He‐MRI
Authors: Deninger A.J. , Eberle B. , Bermuth J. , Escat B. , Markstaller K. , Schmiedeskamp J. , Schreiber W.G. , Surkau R. , Otten E. , Kauczor H.‐U.
Published: September 2002

MRI of the lungs using hyperpolarized helium‐3 (3He) allows the determination of intrapulmonary oxygen partial pressures (pO2). The need to separate competing processes of signal loss has hitherto required two different imaging series during two different breathing maneuvers. In this work, a new imaging strategy to measure pO2 by a single series of consecutive scans is presented. The feasibility of the method is demonstrated in three healthy human volunteers. Maps and histograms of intrapulmonary pO2 are calculated. Changes in the oxygen concentration of the inhaled gas mixture are well reproduced in the histograms. Monte Carlo (MC) simulations of the temporal evolution of 3He hyperpolarization within the lungs were performed to evaluate the accuracy of this measurement technique, and its limitations. Magn Reson Med 47:105–114, 2002. © 2002 Wiley‐Liss, Inc.
Online motion correction for diffusion‐weighted imaging using navigator echoes: Application to RARE imaging without sensitivity loss
Authors: Norris David G. , Driesel Wolfgang
Published: September 2002

This article describes the first application of true online motion correction to diffusion‐weighted RARE imaging. Two orthogonal navigator echoes were acquired and zeroth and first‐order phase corrections applied in less than 8 ms between a diffusion‐weighted magnetization preparation and data acquisition using the RARE sequence. The zeroth‐order phase correction was realized by pulsing the system's B0‐coil: the first‐order error corrected with appropriate magnetic field gradient pulses. Online correction ensured that no irreversible signal loss could occur in the imaging experiment. Diffusion‐weighted images of the brain were obtained from healthy volunteers. EGG‐triggered acquisition was applied at 400 ms after the R‐wave. Data were acquired on a matrix of 256 × 256 with a RARE factor of 16 and a b‐value of 804 smm−2. The images obtained with online motion correction showed a remarkably high image quality, while those acquired without motion correction were severely degraded by artifacts. Magn Reson Med 45:729–733, 2001. © 2001 Wiley‐Liss, Inc.
High‐resolution 1H NMR and magic angle spinning NMR spectroscopic investigation of the biochemical effects of 2‐bromoethanamine in intact renal and hepatic tissue
Authors: Garrod S. , Humpher E. , Connor S.C. , Connelly J.C. , Spraul M. , Nicholson J.K. , Holmes E.
Published: September 2002

The metabolic consequences of xenobiotic‐induced toxicity were investigated using high‐resolution magic angle spinning (MAS) NMR spectroscopy of intact tissue. Renal papillary necrosis (RPN) was induced in Sprague‐Dawley rats (n = 12) via a single i.p. dose of 250 mg/kg 2‐bromoethanamine (BEA) hydrobromide. At 2, 4, 6, and 24 h after treatment with BEA, three animals were killed and tissue samples were obtained from liver, renal cortex, and renal medulla. Tissue samples were also removed at 2 and 24 h from matched controls (n = 6). 1H MAS NMR spectroscopic techniques were used to analyze samples of intact tissue (∼10 mg). Decreased levels of nonperturbing renal osmolytes (glycerophosphocholine, betaine, and myo‐inositol) were observed in the renal papilla of BEA‐treated animals at 6 and 24 h postdose (p.d.), concomitant with a relative increase in the tissue concentration of creatine. Increased levels of glutaric acid were found in all tissues studied in BEA‐treated animals at 4 and 6 h p.d., indicating the inhibition of mitochondrial fatty acyl CoA dehydrogenases and mitochondrial dysfunction. Increased levels of trimethylamine‐N‐oxide occurred in the renal cortex at 6 h p.d. Changes in the metabolite profile of liver included an increase in the relative concentrations of triglycerides, lysine, and leucine. The novel application of 1H MAS NMR to the biochemical analysis of intact tissues following a toxic insult highlights the potential of this technique as a toxicological probe in providing a direct link between urinary biomarkers of toxicity and histopathological evaluation of toxicological lesions. Magn Reson Med 45:781–790, 2001. © 2001 Wiley‐Liss, Inc.
Relative changes of cerebral arterial and venous blood volumes during increased cerebral blood flow: Implications for BOLD fMRI
Authors: Lee Sang‐Pil , Duong Timothy Q. , Yang Guang , Iadecola Costantino , Kim Seong‐Gi
Published: September 2002

Measurement of cerebral arterial and venous blood volumes during increased cerebral blood flow can provide important information regarding hemodynamic regulation under normal, pathological, and neuronally active conditions. In particular, the change in venous blood volume induced by neural activity is one critical component of the blood oxygenation level‐dependent (BOLD) signal because BOLD contrast is dependent only on venous blood, not arterial blood. Thus, relative venous and arterial blood volume (rCBV) and cerebral blood flow (rCBF) in α‐chlorolase‐anesthetized rats under hypercapnia were measured by novel diffusion‐weighted 19F NMR following an i.v. administration of intravascular tracer, perfluorocarbons, and continuous arterial spin labeling methods, respectively. The relationship between rCBF and total rCBV during hypercapnia was rCBV(total) = rCBF0.40, which is consistent with previous PET measurement in monkeys. This relationship can be linearized in a CBF range of 50–130 ml/100 g/min as ΔrCBV(total)/ ΔrCBF = 0.31 where ΔrCBV and ΔrCBF represent rCBV and rCBF changes. The average arterial volume fraction was 0.25 at a basal condition with CBF of ∼60 ml/100 g/min and increased up to 0.4 during hypercapnia. The change in venous rCBV was 2‐fold smaller than that of total rCBV (ΔrCBV(vein)/ΔrCBF = 0.15), while the arterial rCBV change was 2.5 times larger than that of total rCBV (ΔrCBV(artery)/ΔrCBF = 0.79). These NMR results were confirmed by vessel diameter measurements with in vivo videomicroscopy. The absolute venous blood volume change contributes up to 36% of the total blood volume change during hypercapnia. Our findings provide a quantitative physiological model of BOLD contrast. Magn Reson Med 45:791–800, 2001. © 2001 Wiley‐Liss, Inc.
Accurate phosphorus metabolite images of the human heart by 3D acquisition‐weighted CSI
Authors: Pohmann Rolf , von Kienlin Markus
Published: September 2002

Fourier imaging modalities suffer from significant signal contamination between adjacent voxels, especially when the spatial resolution is comparable to the size of the anatomical structures. This contamination can be positive or negative, depending on the spatial response function and the geometry of the object. Such a situation arises in human cardiac 31P chemical shift imaging (CSI). Acquisition‐weighted CSI reduces this contamination substantially, which is demonstrated by comparing conventional CSI to Hanning‐weighted 3D 31P‐CSI experiments in 13 healthy volunteers at 2 T. The nominal spatial resolution and the total number of scans were identical for both experiments. The improved spatial response function of the acquisition‐weighted experiment led to a significantly (P < 0.0001) higher myocardial PCr/ATP ratio (2.05 ± 0.31, mean ± SD, N = 33, corrected for saturation and blood contribution) compared to the conventional CSI experiment (1.60 ± 0.46). This is explained by the absence of negative contamination from skeletal muscle, which also resulted in an increase of the observed SNR (from 5.4 ± 1.4 to 7.2 ± 1.4 for ATP). With acquisition‐weighted CSI, metabolic images with a nominal resolution of 16 ml could be obtained in a measurement time of 30 min. After correction for the inhomogeneous B1 field of the surface coil, these images show uniform ATP distribution in the entire myocardium, including the posterior wall. Magn Reson Med 45:817–826, 2001. © 2001 Wiley‐Liss, Inc.
Direct reconstruction of non‐Cartesian k‐space data using a nonuniform fast Fourier transform
Authors: Sarty Gordon E. , Bennett Raoqiong , Cox Robert W.
Published: September 2002

An algorithm of Dutt and Rokhlin (SIAM J Sci Comput 1993;14:1368–1383) for the computation of a fast Fourier transform (FFT) of nonuniformly‐spaced data samples has been extended to two dimensions for application to MRI image reconstruction. The 2D nonuniform or generalized FFT (GFFT) was applied to the reconstruction of simulated MRI data collected on radially oriented sinusoidal excursions in k‐space (ROSE) and spiral k‐space trajectories. The GFFT was compared to conventional Kaiser‐Bessel kernel convolution regridding reconstruction in terms of image reconstruction quality and speed of computation. Images reconstructed with the GFFT were similar in quality to the Kaiser‐Bessel kernel reconstructions for 2562 pixel image reconstructions, and were more accurate for smaller 642 pixel image reconstructions. Close inspection of the GFFT reveals it to be equivalent to a convolution regridding method with a Gaussian kernel. The Gaussian kernel had been dismissed in earlier literature as nonoptimal compared to the Kaiser‐Bessel kernel, but a theorem for the GFFT, bounding the approximation error, and the results of the numerical experiments presented here show that this dismissal was based on a nonoptimal selection of Gaussian function. Magn Reson Med 45:908–915, 2001. © 2001 Wiley‐Liss, Inc.
Successful treatment of myasthenia gravis with tacrolimus
Authors: Evoli Amelia , Di Schino Chiara , Marsili Francesca , Punzi Chiara
Published: September 2002

Tacrolimus (FK‐506) is a calcium‐calcineurin inhibitor, successfully used in transplant recipients. We report the successful use of tacrolimus as a single immunosuppressant in a patient who had developed myasthenia gravis (MG) during interferon alpha treatment. In this case, the coexistence of hepatitis C and type 2 diabetes mellitus contraindicated the use of both steroids and azathioprine, and cyclosporine A, although effective, had induced renal failure. Tacrolimus proved to be effective in the treatment of MG, was not significantly hepatotoxic, and was less nephrotoxic than cyclosporine. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 111–114, 2002
Neurogenic involvement in a case of oculopharyngeal muscular dystrophy
Authors: Boukriche Yassine , Maisonobe Thierry , Masson Catherine
Published: September 2002

We report the case of a 65‐year‐old man with a 15‐year history of oculopharyngeal muscular dystrophy (OPMD) harboring a (GCG)11 mutation of the poly(A)‐binding protein 2 (PABP2) gene. He developed, early in the course of the disease, a severe chronic axonal neuropathy. Although the primary myopathic origin of the disease appears to be established, a small number of cases of OPMD with neuropathic features have been described. This case raises the question of a possible neurogenic component to this disease and the role of the length of the mutation in phenotype severity. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 98–101, 2002
The effects of microscopic tissue parameters on the diffusion weighted magnetic resonance imaging experiment
Authors: Norris David G.
Published: September 2002

This review examines the way in which microscopic tissue parameters can affect MR experiments which are sensitive to diffusion. The interaction between the intra‐ and extravascular as well as that between the intra‐ and extracellular spaces is examined. Susceptibility gradients due to the presence of deoxyhemoglobin can cause diffusion‐induced signal losses which are significant in functional magnetic resonance experiments, particularly at higher main magnetic field strengths. This is also true of the fast response that manifests itself as an early negative signal change in functional magnetic resonance experiments. The fields surrounding paramagnetic vessels are described and the way in which diffusion in these fields contributes to functional signal changes is examined. Flow in the capillary bed can be a confounding factor in experiments which aim to examine the diffusion characteristics of extravascular water. It is potentially also a method for assessing capillary perfusion. The intravoxel incoherent motion experiment is described in terms of how significantly this effect can influence diffusion attenuation curves from water. The major models for describing water diffusion in tissue are presented, as are the main experimental results that have contributed to an understanding of the mechanisms of diffusion contrast. The widely accepted view that changes in the diffusion characteristics are caused by a shift of water to the intracellular space and a concomitant change in extracellular tortuosity is examined critically. More recent experiments that indicate that a reduction in the intracellular diffusion may occur simultaneously with the cell swelling are described and their compatibility with existing models discussed. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

2FDG‐6P

fluor‐2‐deoxyglucose‐6‐phosphate

ADC

apparent diffusion coefficient

BOLD

blood oxygen level dependent

CNS

central nervous system

CSF

cerebro spinal fluid

DTI

diffusion tensor imaging

DWI

diffusion weighted imaging

fMR

functional magnetic resonance

FR

fast response

IVCM

intravoxel coherent motion

IVIM

intravoxel incoherent motion

MCAO

middle cerebral artery occlusion

MRI

magnetic resonance imaging

NMDA

N‐methyl‐D‐aspartate

NMR

nuclear magnetic resonance

PFG

pulsed field gradient

rBF

regional blood flow

SGP

short gradient pulse

TE

echo time.
Diffusion NMR spectroscopy
Authors: Nicolay Klaas , Braun Kees P. J. , Graaf Robin A. de , Dijkhuizen Rick M. , Kruiskamp Marijn J.
Published: September 2002

MR offers unique tools for measuring molecular diffusion. This review focuses on the use of diffusion‐weighted MR spectroscopy (DW‐MRS) to non‐invasively quantitate the translational displacement of endogenous metabolites in intact mammalian tissues. Most of the metabolites that are observed by in vivo MRS are predominantly located in the intracellular compartment. DW‐MRS is of fundamental interest because it enables one to probe the in situ status of the intracellular space from the diffusion characteristics of the metabolites, while at the same time providing information on the intrinsic diffusion properties of the metabolites themselves. Alternative techniques require the introduction of exogenous probe molecules, which involves invasive procedures, and are also unable to measure molecular diffusion in and throughout intact tissues. The length scale of the process(es) probed by MR is in the micrometer range which is of the same order as the dimensions of many intracellular entities. DW‐MRS has been used to estimate the dimensions of the cellular elements that restrict intracellular metabolite diffusion in muscle and nerve tissue. In addition, it has been shown that DW‐MRS can provide novel information on the cellular response to pathophysiological changes in relation to a range of disorders, including ischemia and excitotoxicity of the brain and cancer. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ADC

apparent diffusion coefficient

ADP

adenosine diphosphate

Cho

choline‐containing compounds

DW

diffusion‐weighted

2FDG‐6P

2‐fluoro‐2‐deoxyglucose‐6‐phosphate

geMQC

gradient‐enhanced, multiple‐quantum coherence

NAA

N‐acetylaspartate

PCr

phosphocreatine

PFG

pulsed field gradient

PRESS

point‐resolved spectroscopy

STEAM

stimulated‐echo acquisition mode

tCr

total creatine/phosphocreatine.
Wavelets and related time‐frequency techniques in magnetic resonance spectroscopy
Authors: Antoine J.‐P. , Chauvin C. , Coron A.
Published: September 2002

We survey the various applications in MRS of the wavelet transform and related time‐frequency methods. For the sake of completeness, we first quickly review the mathematical tools needed. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

CWT

continuous wavelet transform

DWT

discrete wavelet transform

FT

Fourier transform

WT

wavelet transform

WV

Wignes–Ville.
Dopamine and sensory tissue development in Drosophila melanogaster
Authors: Neckameyer Wendi , O'Donnell Janis , Huang Zhinong , Stark William
Published: September 2002

Dopamine is an important signaling molecule in the nervous system; it also plays a vital role in the development of diverse non‐neuronal tissues in the fruit fly Drosophila melanogaster. The current study demonstrates that males depleted of dopamine as third instar larvae (via inhibition of the biosynthetic enzyme tyrosine hydroxylase) demonstrated abnormalities in courtship behavior as adults. These defects were suggestive of abnormalities in sensory perception and/or processing. Electroretinograms (ERGs) of eyes from adults depleted of dopamine for 1 day as third instar larvae revealed diminished or absent on‐ and off‐transients. These sensory defects were rescued by the addition of L‐DOPA in conjunction with tyrosine hydroxylase inhibition during the larval stage. Depletion of dopamine in the first or second larval instar was lethal, but this was not due to a general inhibition of proliferative cells. To establish that dopamine was synthesized in tissues destined to become part of the adult sensory apparatus, transgenic lines were generated containing 1 or 4 kb of 5′ upstream sequences from the Drosophila tyrosine hydroxylase gene (DTH) fused to the E. coli β‐galactosidase reporter. The DTH promoters directed expression of the reporter gene in discrete and consistent patterns within the imaginal discs, in addition to the expected expression in gonadal, brain, and cuticular tissues. The β‐galactosidase expression colocalized with tyrosine hydroxylase protein. These results are consistent with a developmental requirement for dopamine in the normal physiology of adult sensory tissues. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 280–294, 2001
Preparation of the first tricoordinate silyl cation
Authors: Lambert Joseph B. , Zhao Yan , Zhang S. Mark
Published: September 2002

The preparation of the first tricoordinate silyl cation was made possible by a sequence of discoveries over a 20 year period. The extremely high electrophilicity of the material required protection from all manner of nucleophiles. Only arenes had sufficiently low nucleophilicity to serve as solvent. Tetrakis(pentafluorophenyl) borate provided the least nucleophilic anion. All manipulations had to be carried out in an inert atmosphere, primarily as protection from moisture. Sterically bulky substituents such as mesityl were needed to protect the cation even from the optimized solvent and anion. The trimesitylsilylium ion was produced from allyltrimesitylsilane by reaction of electrophiles with the allyl double bond and extrusion of the allyl adduct. Copyright © 2001 John Wiley & Sons, Ltd.
Syndiospecific polymerization of styrene catalyzed by CpTiCl2(OR) complexes
Authors: Ma Haiyan , Zhang Yue , Chen Bin , Huang Jiling , Qian Yanlong
Published: September 2002

Five new CpTiCl2(OR) alkoxyl‐substituted half‐sandwich complexes, where R was methoxyethyl (1), methoxypropyl (2), methoxyisopropyl (3), o‐methoxyphenyl (4), or tetrahydrofurfuryl (5), were synthesized, characterized, and tested as catalyst precursors for the syndiospecific polymerization of styrene. These precursors were more active than (η5‐cyclopentadienyl)trichlorotitanium (CpTiCl3). The different structures of the alkoxyl ligands affected the activity slightly. When the polymerization was carried out in bulk, all the complexes (1–5) exhibited high activities, even at the low molar ratio of Al/Ti = 300. The syndiotactic polystyrene (s‐PS) percentage of the polymer produced by alkoxyl‐substituted complexes was much higher than that of CpTiCl3. The really active center might be described as [CpTiMe]+ · [MAOX]− · nMAO (where MAO is methylaluminoxane). The normal active species [CpTiMe]+ made up the core and the anion mass [MAOX]− · nMAO surrounded the core and constituted the outer shell circumstance. They activated the syndiospecific polymerization of styrene as a whole. For a high concentration of MAO, the function of the alkoxyl group was weak because of the limited proportion in the outer shell. For a low concentration of MAO, the proportion of alkoxyl ligands in the outer shell increased greatly, and their influence also became significant, as reflected in a higher s‐PS percentage of the obtained polymer. The existence of the additional oxygen atom in the alkoxyl ligand stabilized the active species more effectively; this was reflected in the higher temperature of the maximum activities. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1817–1824, 2001
Homopolymerization and [2 + 4]/[3 + 2] cycloaddition in the reaction of nitroethylene with vinyl ethers
Authors: Shin Won‐Suk , Padias Anne Buyle , Hall, H. K.
Published: September 2002

The reaction of nitroethylene with isobutyl vinyl ether was reinvestigated. In agreement with the report of Kushibiki, Irie, and Hayashi (J Polym Sci Polym Chem Ed 1975, 13, 77), cycloaddition accompanied the anionic homopolymerization of nitroethylene. However, the cycloadduct was not a cyclobutane but a bicyclic oxazolidine, in keeping with the more recent report by Denmark and Hurd (J Org Chem 1998, 63, 3045). Cycloaddition accompanied by the anionic homopolymerization of nitroethylene was general for a series of vinyl and silyl ethers. Mechanistically, the cycloadducts formed by a cis–syn concerted approach of the reactants, whereas a trans–anti approach gave a zwitterionic tetramethylene that initiated anionic homopolymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1886–1891, 2001
Active‐center equilibrium in Ziegler–Natta butadiene polymerization
Authors: Cass Peter , Pratt Kerry , Fairhall Kim , Laslett Bob , Rizzardo Ezio
Published: September 2002

The Ziegler–Natta‐catalyzed polymerization of 1,3‐butadiene was investigated at a low aluminum alkyl/cobalt (Al/Co) ratio using two different soluble catalyst systems: cobalt(II) octanoate/diethylaluminum chloride/water and cobalt(II) octanoate/methylaluminoxane/tert‐butyl chloride. When the active‐center concentration was determined by the number‐average molecular weight technique, it was found that the percentage of active cobalt depended on the Al/Co ratio. Subsequently, an equilibrium reaction was proposed to be Co + 2Al ⇌ CoAl2, where Co is cobalt(II) octanoate, Al is either of the aluminum alkyl‐activator species, and CoAl2 is the active catalyst. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2256–2261, 2001
Synthesis and properties of amorphous blue‐light‐emitting polymers with high glass‐transition temperatures
Authors: Deimede V. , Kallitsis J. K. , Pakula T.
Published: September 2002

A series of soluble poly(arylene ether)s containing the phenylphosphine oxide moiety were synthesized by the polymerization of substituted oligophenylene diols with bis(fluorophenyl)phenylphosphine oxide. These amorphous polyethers had well‐defined structures and showed blue photoluminescence combined with good thermal stability, especially when phenyl or ethoxy side groups were used. The glass‐transition temperatures increased when the size of the oligophenylene segment increased from three to five rings or when the length of the alkoxy substituents decreased. Polymers with glass‐transition temperatures up to 270 °C were obtained. The absorption and photoluminescent spectra shifted to longer wavelengths with an increase in the oligophenylene block. A redshift was also observed on photoluminescent spectra in the transition from solution to the solid state. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3168–3179, 2001
Helix formation of poly(phenylacetylene) derivatives bearing amino groups at the meta position induced by optically active carboxylic acids
Authors: Maeda Katsuhiro , Okada Seiji , Yashima Eiji , Okamoto Yoshio
Published: September 2002

Two novel phenylacetylene derivatives bearing diethylaminomethyl groups at the meta position on phenyl groups [3‐(N,N‐diethylaminomethyl)phenyl]acetylene (1) and [3,5‐bis(N,N‐diethylaminomethyl)phenyl]acetylene (2) were synthesized and polymerized with [Rh(nbd)Cl]2 (nbd: norbornadiene). Both monomers gave highly cis–transoidal stereoregular polymers that exhibited an induced circular dichroism (ICD) in the UV–visible region, probably because of a prevailing one‐handed helical conformation upon complexation with optically active carboxylic acids such as mandelic acid and lactic acid. The sign of the Cotton effects reflected the absolute configuration of the chiral acids. Therefore, these polymers can be used as a novel probe for determining the configuration of chiral acids. The polymers were stable in the presence of chiral acids in solution. The poly‐1 complexed with chiral acids exhibited a split‐type ICD, whereas the poly‐2 complexed with chiral acids showed a different, non‐split‐type ICD. The ICD pattern of the poly‐1/chiral acids complexes dramatically changed with an increase in the concentration of the chiral acids, thus showing a non‐split‐type ICD similar to those of the poly‐2/chiral acid complexes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3180–3189, 2001
Online monitoring of birefringence development in heat‐setting polymer films with a fast dual‐wavelength optical technique. II. Uniaxially oriented PEN/PEI films
Authors: Galay J. , Cakmak M.
Published: September 2002

The influence of poly(ether imide) (PEI) on the structural ordering process in heat setting from the preoriented state of poly(ethylene 2,6‐naphthalene dicarboxylate) (PEN)/PEI blend films was investigated with the two‐color online birefringence system. The addition of small amounts of noncrystallizable PEI enhanced the crystallization from the preoriented state. This was attributed to the loosening of the structure with the addition of lower density and bulkier PEI at small concentrations. With a maximum effect around 15% PEI, a further increase in the concentration resulted in a dilution effect that spatially separated the crystallizable PEN chains. This slowed down the structural rearrangement process during heat setting. At elevated temperatures, the real‐time birefringence data obtained from the developed two‐color birefringence system temporally located the relaxation that followed with an increase in birefringence. This was associated with molecular relaxation due to melting followed by crystallization and partial reorientation of crystalline regions in the original stretching direction. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1147–1159, 2001
A novel ionic‐conduction mechanism based on polyurethane electrolyte
Authors: Zhu Weihua , Wang Xinling , Yang Bing , Tang Xiaozhen
Published: September 2002

A series of poly(ethylene glycol)–polyurethane (PEG–PU)/sodium perchlorate (NaClO4) solid electrolytes were prepared, and their properties were characterized with Fourier transform infrared spectroscopy, differential scanning calorimetry, complex impedance analysis, and atomic force microscopy. Results showed that the oxygen atoms of carbonyl and ether oxygen groups had different activities on cations. Both carbonyl and ether oxygen groups participated in the ionic‐transport process in PU‐based electrolytes. There existed a coordination competition between sodium cations and different oxygen atoms in soft and hard segments of PU. For the PEG–PU/NaClO4 system investigated, amorphous regions and interfacial regions between the amorphous and microcrystalline phases were responsible for ionic conduction. A new ionic‐transport mechanism, based on the existence of conduction pathways not only in amorphous regions but also in interfacial regions of microphase‐separated PU‐based electrolytes, is sketched. Moreover, at a particular concentration of doped salt (EO/NaClO4 12), the PEG–PU/NaClO4 complex revealed a phase‐transition point in the morphology and exhibited minimum apparent activation energy and maximum ionic conductivity. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1246–1254, 2001
Detecting social problems in cancer patients
Authors: Wright E.P. , Selby P.J. , Gould A. , Cull A.
Published: September 2002

Diagnosis of and treatment for cancer may not only create physical and emotional difficulties for patients but may also have an impact on social aspects of patients' lives. Screening for social problems has not become part of routine oncology practice. This may be due to lack of a suitable questionnaire. This paper presents a psychometric analysis of the Problems Checklist with a view to assessing its usefulness as a screening tool for social problems in oncology. Evaluation was undertaken using data from an earlier study of 505 patients who completed the checklist. Frequency of endorsement, missing values, factor analysis and reliability and validity analysis of the summated scales were carried out. Missing data rates ranged from 4 to 18% over the 16 items. Fourteen items were well endorsed. Factor analysis produced a four‐factor structure with components labelled daily living, relationships, economics and emotions. Reliability and validity tests endorsed the factor structure with the components on economics and emotions being particularly credible. Difficulties with relationships are harder to measure and results from the analysis suggest that this is an area that warrants further investigation. The checklist is a useful tool for highlighting problems. As a tool for screening for social problems it has some limitations. Copyright © 2001 John Wiley & Sons, Ltd.
Children with cancer with different survival perspectives: defensiveness, control strategies, and psychological adjustment
Authors: Grootenhuis Martha A. , Last Bob F.
Published: September 2002

The main objective of the present study was to investigate whether children with cancer with different survival perspectives differ in their psychological adjustment, defensiveness and their use of cognitive control strategies. Furthermore, the study investigated which variables predict emotional adjustment of these children with cancer most adequately. A total of n=84 children (n=43 children in remission and n=41 children not in remission) participated in the study. They answered questionnaires about control strategies, defensiveness, anxiety and depression. No differences were found in any of the questionnaires between children in remission and relapse. Emotional adjustment of the children was predicted by defensiveness and by positive expectations about the course of the illness. The findings demonstrate the importance of having positive expectations for the emotional adjustment of children with cancer. The strength of the study is the inclusion of a substantial group of children with cancer who have a reduced survival perspective. Copyright © 2001 John Wiley & Sons, Ltd.
Study of tau‐fluvalinate persistence in honey
Authors: Tsigouri Angeliki D , Menkissoglu‐Spiroudi Urania , Thrasyvoulou Anthreas
Published: September 2002

The persistence of the acaricide tau‐fluvalinate with time and the factors that can affect its degradation in honey were investigated. Two honey types of extreme pH values (3.85 and 5.40) were spiked with tau‐fluvalinate at two levels (50 and 200 µg kg−1) and incubated at 35 °C. Samples were analyzed in duplicate at various time intervals for up to 248 days. A simple, rapid and accurate method for the determination of tau‐fluvalinate residues in honey is proposed. Tau‐fluvalinate extraction and sample cleanup was carried out using C8 SPE cartridges with dichloromethane as the elution solvent. Analysis of samples was accomplished using gas chromatography with electron‐capture detection (GC–ECD). The overall recovery of the method was 90.25(±0.85)% and the limit of determination 1 µg kg−1. The results showed that tau‐fluvalinate stays stable in honey for more than 8 months, even at 35 °C. The effect of higher temperatures, similar to those used for honey packing, on tau‐fluvalinate persistence in honey was also studied. Honey samples fortified with 20 and 200 µg kg−1 tau‐fluvalinate were subjected to heat treatment similar to that in the honey blending and packing process. No degradation of tau‐fluvalinate due to the heat treatment was recorded. This long persistence increases the risk of honey contamination due to repeated and/or extended tau‐fluvalinate applications.

© 2001 Society of Chemical Industry
Fatigue strength of welded joints made of high‐strength steels
Authors: Anami Kengo , Miki Chitoshi
Published: September 2002

By rearranging existing fatigue test results, fatigue performance of typical welded joints, (longitudinal, cruciform and out‐of‐plane gusset welded joint) are discussed with respect to the dependence on steel strength and on joint size. The relationship between fatigue strength and steel strength was not clear for longitudinal welded joints of small specimens and large‐scale girder specimens. For cruciform welded joints and out‐of‐plane gusset welded joints, fatigue strength of small joint specimens is independent of the steel strength, but that of girder specimens decreases with increase in steel strength. In addition, fatigue strengths of these two types of welded joints decrease with increase in joint size, especially for girder specimens.

In order to discuss these relationships in detail, fatigue tests with out‐of‐plane gusset welded joint specimens and large‐scale girder specimens, including web gusset joints made of JIS SM570 and 900 MPa class steel were carried out. From the fatigue tests, similar tendencies were found to those obtained from existing test results. Although fatigue tests of joint specimens showed no difference in fatigue strength, crack initiation life and crack propagation rate between the steel strengths, fatigue strength of girder specimens made of 900 MPa class steels is much lower than for JIS SM570. In addition, fatigue strength of the girder specimens is considerably lower than that of the joint specimens. This difference results mainly from an increase in stress concentration due to joint geometry, and combination of nominal stress and shear stress in the girder specimens. It was found that the influence of the combination can be approximately evaluated from the nominal principal stress.
Steel transmission towers: some current topics
Authors: Urbano Carlo A
Published: September 2002

In developed countries the environmental impact of the traditional transmission towers is no longer accepted. Currently available design solutions with acceptable appearance are not employed in the developing countries, mainly for cost reasons. In the developing countries the use of the traditional lattice transmission towers will continue employing steel angles. A comparison of the available design specifications for steel angles in transmission towers is presented.
The properties and possible transformation path for C12B24N24
Authors: Yin Hong‐Ming , Zhang Rui‐Qin , Yang Ben‐Hui , Han Ke‐Li , He Guo‐Zhong
Published: September 2002

The structure and frequencies of C12B24N24 have been calculated by means of an ab initio method. By comparing the average bond energies with C60, the calculated results predict that the cage C12B24N24 is a stable molecule. The calculated results indicate that the cage molecule C12B24N24 has a relative large HOMO–LUMO energy gap and a low rigidity. The structures and stability of six possible isomers of C2B4N4 are used to suggest a possible transformation path from the pentagon CB2N2 to the C12B24N24 materials. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 363–368, 2001
A phase‐space method for arbitrary bimolecular gas‐phase reactions: Application to the CH3CHO+HO and CH3OOH+HO reactions
Authors: Gross A. , Mikkelsen K. V. , Stockwell W. R.
Published: September 2002

A new method based upon phase‐space methods presented in Ref. 1 (Gross, A.; Mikkelsen, K. V., Stockwell, W. R. Int J Quantum Chem 2001, accepted) has been tested on the reactions CH3CHO+HO→CH3CO+H2O and CH3OOH+HO→products. The method has been used to calculate cross sections, and rate constants in the temperature range 200–550 K. The method requires knowledge of the system's reaction and product channels for the interacting species, the vibrational frequencies, the moments of inertia, and the potential energies of the molecules in their ground state equilibrium configuration. Furthermore, the long‐range potential between the reactant and product species is required. Due to the lack of experimentally determined spectroscopic data and potential energies for the reactants and products, these values have been calculated using electronic structure theory. We have used the many‐body second‐order Møller Plesset perturbation theory (MP2) for the treatment of electron correlation in the molecules, together with two different Gaussian‐type orbital (GTO) basis sets 6‐31G and 6‐31G*. The calculated rates are compared with the experimental data estimated earlier elsewhere. On the basis of our limited tests, the method appears to yield rate constants that are within a factor of 10–25 at 300 K of the true value, which is much more accurate than currently used empirical estimation methods. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Partial rates in the high‐frequency regime of intense‐field photoionization of hydrogen
Authors: Lefebvre R. , Stern B.
Published: September 2002

Complex rotation in the exterior scaling version is applied to the solution of the coupled equations of Floquet theory for ground state hydrogen submitted to an external intense oscillating linearly polarized electric field. The calculations are done in the Kramers–Henneberger frame. The fluxes are calculated in the asymptotic real part of the integration axis. The total and 1‐photon rates are used to reassess the performances of a high‐frequency two‐pole approximation previously developed (J Phys B 1999, 32, 3271). For overthreshold frequencies, the partial rates with definite values of n, the number of absorbed photons, and l, the angular quantum number of the ejected electron, show oscillations which are erased when summing over l. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
The close‐coupling‐single center‐expansion (CC‐SCE) model for electron scattering from polyatomic targets
Authors: Curik R. , Gianturco F. A. , Sanna N.
Published: September 2002

The theoretical and computational study of elastic integral and differential cross sections for fairly large polyatomic targets is described in terms of quantum close‐coupled scattering equations cast within a symmetry‐adapted, single center expansion form of target wavefunctions, continuum electrons, and interaction potential. The latter is introduced in a local, real model form, and examples of its level of agreement with experiments are given for a class of many‐electron, polyatomic molecules like the halogenated silane derivatives. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001
Preparation and mass spectrometric study of egg yolk antibody (IgY) against rabies virus
Authors: Sun Shuqing , Mo Wenjun , Ji Yiping , Liu Shuying
Published: September 2002

Rabies virus was used as the antigen to immunize laying chickens. Anti‐rabies virus immunoglobulin Y(IgY) was isolated from yolks of the eggs laid by these chickens using a two‐step salt precipitation and one‐step gel filtration protocol. The purified IgY was reduced with dithiothreitol, and heavy chains (HC) and light chains (LC) were obtained. In addition, the purified IgY was digested with pepsin and the fragment with specific antigen binding properties (Fab) was produced. Using matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐TOFMS), the average molecular weights of IgY, HC, LC, and Fab were determined as 167 250, 65 105, 18 660, and 45,359 Da, respectively. IgY has two structural differences compared with mammalian IgGs. First, the molecular weight of the heavy chain of IgY is larger than that of its mammalian counterpart, while the molecular weight of the light chain of IgY is smaller. Second, upon pepsin digestion, anti‐rabies virus IgY is degraded into Fab, in contrast to mammalian IgG, which has been reported to be degraded into F(ab′)2 under the same conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Copper(I) chloride: a simple salt for enhancement of polystyrene cationization in matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Kéki Sándor , Deák György , Zsuga Miklós
Published: September 2002

The possibility of using copper(I) chloride as a doping salt to enhance the cationization of polystyrene in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) was investigated. It was shown that copper(I) chloride possesses sufficient solubility in tetrahydrofuran. The parameters of the MALDI mass spectra of different polystyrene samples, such as the number‐average (Mn) and mass‐average (Mw) molecular mass values, obtained by copper(I) cationization were compared with those obtained by means of silver(I) cationization, and good agreement was found. It was also shown that application of copper(I) chloride as a doping salt, and dithranol as a matrix, ensured good MALDI mass spectra of the sample spots even after storage for 1 month. Copyright © 2001 John Wiley & Sons, Ltd.
Gln‐Gly cleavage: a dominant dissociation site in the fragmentation of protonated peptides
Authors: Jonsson Andreas P. , Bergman Tomas , Jörnvall Hans , Griffiths William J.
Published: September 2002

An understanding of the gas‐phase dissociation of protonated peptides within the mass spectrometer is essential for automated high‐throughput protein identification. In this communication we describe a facile cleavage of the Gln‐Gly peptide bond under low‐collisional energy conditions. A variety of synthetic peptides have been analysed where key amino acids have been substituted within the sequence PQGPPQQGGR, which is a consensus repeat present in the tryptic peptides of acidic proline‐rich protein 1 (PRP‐1). The collision‐induced dissociation spectra obtained from the PRP‐1 tryptic peptides and the synthetic peptides indicate that facile Gln‐Gly cleavage occurs when an X‐Gln‐Gly‐Y sequence is present in a peptide, where X is any amino acid and Y any amino acid other than Gly. Copyright © 2001 John Wiley & Sons, Ltd.
Formation of gas‐phase clusters monitored during electrospray mass spectrometry: a study of quaternary ammonium pesticides
Authors: Evans Catherine S. , Startin James R. , Goodall David M. , Keely Brendan J.
Published: September 2002

Gas‐phase cluster formation between the quaternary ammonium pesticides paraquat, diquat, difenzoquat, chlormequat and mepiquat, and chloride and acetate anions present in a liquid chromatography (LC) mobile phase, has been studied using electrospray mass spectrometry. The clusters of paraquat, mepiquat and chlormequat were revealed over the entire m/z range of the mass spectrometer, and their formation is dependent on the concentrations of both the cationic and the anionic species. Mepiquat and chlormequat form clusters of the type [2Mq+ + A−]+, where Mq+ is the quaternary ammonium cation and A− is the anion. Paraquat forms a cluster species with ammonia and also an ion‐pair complex with chloride anions. Diquat and difenzoquat did not form observable ion‐pair complexes or clusters with any of the anions studied. Competitive binding of acetate and chloride anions reflects the higher charge density of chloride, which forms the dominant clusters with mepiquat and chlormequat. The formation of cluster species has implications for the quantification of quaternary ammonium pesticides and may have an influence on the linearity of calibrations. Copyright © 2001 John Wiley & Sons, Ltd.
Composition and structure of enriched alloy layers in filmed Al alloys studied by medium‐energy ion scattering
Authors: Bailey P. , Skeldon P. , Noakes T. C. Q. , Thompson G. E. , Sakairi M. , Habazaki H. , Shimizu K.
Published: September 2002

The topmost 20 nm of an electropolished Al–1 at.% Cu alloy has been investigated at sub‐nanometre resolution using medium‐energy ion scattering. Differences in the composition and depth of the enriched Cu layer are observed. Most significantly, the enriched layer contains regions of differing structure and/or lattice orientation with Cu atoms located in distinct ordered regions, consistent with the presence of Cu‐rich clusters. Surface‐segregated Si and Cu are observed and Cl and Cu are found in the oxide. Copyright © 2001 John Wiley & Sons, Ltd.
Nanopore and nanoparticle catalysts
Authors: Thomas John Meurig , Raja Robert
Published: September 2002

The design, atomic characterization, performance, and relevance to clean technology of two distinct categories of new nanocatalysts are described and interpreted. Exceptional molecular selectivity and high activity are exhibited by these catalysts. The first category consists of extended, crystallographically ordered inorganic solids possessing nanopores (apertures, cages, and channels), the diameters of which fall in the range of about 0.4 to about 1.5 nm, and the second of discrete bimetallic nanoparticles of diameter 1 to 2 nm, distributed more or less uniformly along the inner walls of mesoporous (ca. 3 to 10 nm diameter) silica supports. Using the principles and practices of solid‐state and organometallic chemistry and advanced physico‐chemical techniques for in situ and ex situ characterization, a variety of powerful new catalysts has been evolved. Apart from those that, inter alia, simulate the behavior of enzymes in their specificity, shape selectivity, regio‐selectivity, and ability to function under ambient conditions, many of these new nanocatalysts are also viable as agents for effecting commercially significant processes in a clean, benign, solvent‐free, single‐step fashion. In particular, a bifunctional, molecular sieve nanopore catalyst is described that converts cyclohexanone in air and ammonia to its oxime and caprolactam, and a bimetallic nanoparticle catalyst that selectively converts cyclic polyenes into desirable intermediates. Nanocatalysts in the first category are especially effective in facilitating highly selective oxidations in air, and those in the second are well suited to effecting rapid and selective hydrogenations of a range of organic compounds. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:448–466, 2001
Vectors and gene targeting modules for tandem affinity purification in Schizosaccharomyces pombe
Authors: Tasto Joseph J. , Carnahan Robert H. , Hayes McDonald W. , Gould Kathleen L.
Published: September 2002

We describe the construction of tagging cassettes and plasmids for tandem affinity purification (TAP) of proteins in Schizosaccharomyces pombe. The tagging cassettes are designed for either carboxy‐ or amino‐terminal tagging of proteins. The carboxyl terminal tags differ in that they contain either two or four repeats of IgG binding units. For tagging endogenous loci, the cassettes contain the kan MX6 module to allow for selection of G418‐resistant cells. The amino‐terminal tagging vectors allow for the regulated expression of proteins. Sz. pombe Cdc2p was chosen to test these new affinity tags. Several known binding proteins co‐purified with both Cdc2p‐CTAP and N‐TAP‐Cdc2p, indicating the usefulness of these tags for the rapid purification of stable protein complexes from Sz. pombe. Copyright © 2001 John Wiley & Sons, Ltd.