bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory studies of the ·OH‐initiated photooxidation of ethyl‐n‐butyl ether and di‐n‐butyl ether
Authors: Johnson D. , Andino J. M.
Published: September 2002

Oxygenated compounds such as ethers and alcohols are used as gasoline additives and industrial solvents. However, despite their widespread use, the atmospheric reaction mechanisms of some of these compounds are unknown. This study examines the ·OH‐initiated gas‐phase removal mechanisms of ethyl‐n‐butyl ether (ENBE) and di‐n‐butyl ether (DNBE) utilizing gas chromatography–mass spectrometry techniques. The primary products and molar yields from the hydroxyl‐radical–initiated photooxidation of ENBE in the presence of nitric oxide were acetaldehyde (0.173 ± 0.012), ethyl formate (0.219 ± 0.033), butyraldehyde (0.076 ± 0.004), butyl formate (0.241 ± 0.009), butyl acetate (0.032 ± 0.001), and ethyl butyrate (0.0044 ± 0.0006). From the calculated molar yields, approximately 45.5% of the reacted carbon were recovered. The primary products and molar yields from the DNBE and hydroxyl radical reaction in the presence of nitric oxide were propionaldehyde (0.379 ± 0.022), butyraldehyde (0.119 ± 0.003), butyl formate (0.410 ± 0.009), and butyl butyrate (0.019 ± 0.001). Approximately 47.7% of the reacted DNBE were recovered. The chemical mechanisms are presented to explain the formation of these products. In addition, the importance of the isomerization and nitrate/nitrite formation pathways in the reactions of large ethers are discussed. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 328–341, 2001
Pressure effects on cation migration in 2,5‐di‐tert‐butyl‐1,4‐benzoquinone radical anion
Authors: Kasahara Masamichi , Sueishi Yoshimi , Yamamoto Shunzo
Published: September 2002

Pressure effects on the two‐site jumping of sodium and potassium cations in a 2,5‐di‐tert‐butyl‐1,4‐benzoquinone ion pair have been studied using a high‐pressure EPR technique. The rate constants of the intramolecular and intermolecular migrations for Na+ and K+ were determined from an EPR spectral simulation. The migration rates were found to be accelerated by increasing the external pressure. Using the pressure dependence of the migration rates, we estimated the activation volumes of the intramolecular (ΔV1‡) and intermolecular (ΔV2‡) processes for the Na+ and K+ migrations: ΔV1‡ = −5.3 cm3 mol−1 and ΔV2‡ = −29 cm3 mol−1 for Na+, and ΔV1‡ = −8.3 cm3 mol−1 and ΔV2‡ = −0.85 cm3 mol−1 for K+. Based on the results, the mechanisms for the two‐site jumping of Na+ and K+ are discussed in terms of volume. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 397–401, 2001
Kinetics and mechanism of alkaline hydrolysis of 4‐nitrophthalimide in the absence and presence of cationic micelles
Authors: Niyaz Khan M. , Abdullah Zunoliza
Published: September 2002

Pseudo‐first‐order rate constants (kobs) for alkaline hydrolysis of 4‐nitrophthalimide (NPTH) decreased by nearly 8‐ and 6‐fold with the increase in the total concentration of cetyltrimethyl‐ammonium bromide ([CTABr]T) from 0 to 0.02 M at 0.01 and 0.05 M NaOH, respectively. These observations are explained in terms of the pseudophase model and pseudophase ion‐exchange model of micelle. The increase in the contents of CH3CN from 1 to 70% v/v and CH3OH from 0 to 80% v/v in mixed aqueous solvents decreases kobs by nearly 12‐ and 11‐fold, respectively. The values of kobs increase by nearly 27% with the increase in the ionic strength from 0.03 to 3.0 M. The mechanism of alkaline hydrolysis of NPTH involves the reactions between HO− and nonionized NPTH as well as between HO− and ionized NPTH. The micellar inhibition of the rate of alkaline hydrolysis of NPTH is attributed to medium polarity effect. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 407–414, 2001
Oxidation of ethanolamines by sodium N‐bromobenzenesulfonamide in alkaline buffer medium: A kinetic and mechanistic study
Authors: Puttaswamy  , Vaz Nirmala , Made Gowda N. M.
Published: September 2002

The kinetics of oxidation of ethanolamines, monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA), by sodium N‐bromobenzenesulfonamide or bromamine‐B (BAB) in alkaline buffer medium (pH 8.7–12.2) has been studied at 40°C. The three reactions follow identical kinetics with first‐order in [oxidant] and fractional‐order each in [substrate] and [OH−]. Under comparable experimental conditions, the rate of oxidation increases in the order: DEA > TEA > MEA. The added reaction product, benzenesulfonamide, retards the reaction rate. The addition of halide ions and the variation of ionic strength of the medium have no significant effect on the rate. The dielectric effect is negative. The solvent isotope effect k′(H2O)/k′(D2O) ≈ 0.92. Activation parameters for the composite reaction and for the rate‐limiting step were computed from the Eyring plots. Michaelis‐Menten type of kinetics is observed. The formation and decomposition constants of ethanolamine‐BAB complexes are evaluated. An isokinetic relationship is observed with β = 430 K indicating that enthalpy factors control the rate. For each substrate, a mechanism consistent with the kinetic data has been proposed. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 480–490, 2001
Multi‐factorial causes of land‐use change: land‐use dynamics in the agropastoral village of Im Mial, northwestern Syria
Authors: Nielsen T. L. , Zöbisch M. A.
Published: September 2002

Land‐use dynamics in drylands are complex processes. In the context of a typical agropastoral village in northwestern Syria Im Mial, the effects of demographic and social changes, reduced soil productivity, changes in agricultural technologies and historical events on land use and land productivity are examined. Decreasing yields, mainly the result of reduced fallow periods and low investments in the land, and the deterioration of the grazing resources are the two main signs of the loss of land productivity in the area. The growing population forces the villagers to practise continuous rainfed barley cultivation with no or only occasional fallow, and without any application of plant nutrients. Also, technological changes, from the use of donkey ploughs and hand harvesting to less labour‐intensive and time‐consuming cultivation practices with tractors and combine harvesters, and the increased importance of stubble in the livestock diet have contributed to the reduction of the fallow periods. The villagers attribute the yield decreases mainly to the low rainfall in the area. The high rainfall variability discourages the fallowing of fields because continuous cultivation maximizes the chances for good harvests in years with high rainfall. There is also an expansion of cultivation into the less fertile and sloping traditional grazing areas. Population growth, increased numbers of livestock and the expansion of cultivated land into grazing areas has also put pressure on the grazing resources of the village. The possession of livestock is seen as a sign of wealth and the villagers aim to have large flocks of animals. For them, livestock is also an important means for investment of cash earned from off‐farm work, which is the main source of income for most of the households in the village. There is a recent trend of increasing levels of crop‐livestock integration with less free grazing that produces higher return to the land users. This may also have a positive effect on the restoration and conservation of the degraded natural traditional grazing grounds. The stabilization and productive use of the land resources in this dry environment requires the combined and interdisciplinary effort from both the land‐users and the policy‐makers. Copyright © 2001 John Wiley & Sons, Ltd.
Consumer vulnerability to scams, swindles, and fraud: A new theory of visceral influences on persuasion
Authors: Langenderfer Jeff , Shimp Terence A.
Published: September 2002

Scams exact a huge toll on consumers and society at large, with annual costs in the United States alone exceeding $100 billion. The global proliferation of the Internet has enabled con artists to export their craft to a rapidly expanding market and reach previously untapped consumers. In spite of the prevalence of scams around the world, there has been virtually no academic attention devoted to understanding the factors that might account for why individuals differ in their scamming vulnerability. Building on the background of elder consumer disadvantage and informed by the authors' own survey of expert opinion, this article presents a tentative theory of scamming vulnerability. The proposed theory incorporates the effects of visceral influences on consumer response to scam offers and hypothesizes a role for various moderating factors such as self‐control, gullibility, susceptibility to interpersonal influence, and scam knowledge. Theoretical propositions are provided for future empirical investigation. © 2001 John Wiley & Sons, Inc.
Gotcha! Findings from an exploratory investigation on the dangers of using deceptive practices in the mail‐order business
Authors: Vanhamme Joëlle , Lindgreen Adam
Published: September 2002

This exploratory investigation examines the impact of some Belgian mail‐order companies' deceptive practices—specifically, the use of gifts—on long‐term relationships with their customers. The results support the premise that the use of deceptive gifts first elicits negative surprise and, subsequently, disappointment or even outrage. Deceptive gifts also seem to have a negative impact on the company's brand image and on the trust customers place in the company and its products. The results also suggest that the use of deceptive gifts hinders customer retention and customer loyalty. Moreover, deceptive gifts deprive the company of valuable advantages, such as preference for its products and positive perceptions of the company and its products, which could result from using non‐deceptive gifts. © 2001 John Wiley & Sons, Inc.
Biopolymer mechanics: stability, dynamics, and statistics
Authors: Wiggins Chris H.
Published: September 2002

Motivated by the dynamics of twisted biopolymers such as DNA and filaments ofBacillus subtilis, we formulate the over‐damped dynamics of a twisted elastic rod. The development exploits the ‘natural’ frame, in which curve dynamics are described by a pair of non‐linear partial differential equations, partitioning bending from twisting motions and highlighting their geometric interplay. A number of open problems are highlighted, along with connections with questions about cellular structure and statistical dynamics. Copyright © 2001 John Wiley & Sons, Ltd.
The LGL (Lighthill–Gueron–Liron) Theorem—historical perspective and critique
Authors: Liron Nadav
Published: September 2002

The 1970s saw a series of works on the modelling of slender bodies moving in slow flow (Re=0), instigated by the interest to understand the principles underlying the swimming of ciliates and flagellates. It was Lighthill in 1975, who wrote down the first theorem connecting slender body motion and singularities distributions along the centre line. This paper will describe the historical development from the early results through Lighthill's theorem to the Gueron–Liron Theorem, which enables discrete‐cilia modelling, i.e., modelling of a multitude of slender bodies attached to a surface. Copyright © 2001 John Wiley & Sons, Ltd.
Smectic A liquid crystal configurations with interface defects
Authors: Calderer M. Carme , Liu Chun , Voss Karl
Published: September 2002

We study planar energy minimizing configurations of smectic A liquid crystal materials and classify the corresponding defect structures. We investigate focal conic configurations in wedge, non‐parallel plates, funnel‐shaped domains, and non‐concentric annuli. The application of the stability condition for focal conics is relevant to the specification of the location of the interfacial defects. Self‐similar structures are discussed for a class of solutions with the same bulk energy. We propose surface energies terms to serve as selection mechanisms of particular self‐similar configurations. We also show how the modelling of chevron texture naturally arises in the present framework. Copyright © 2001 John Wiley & Sons, Ltd.
Eigen‐frequencies in thin elastic 3‐D domains and Reissner–Mindlin plate models
Authors: Dauge Monique , Yosibash Zohar
Published: September 2002

The eigen‐frequencies of elastic three‐dimensional thin plates are addressed and compared to the eigen‐frequencies of two‐dimensional Reissner–Mindlin plate models obtained by dimension reduction. The qualitative mathematical analysis is supported by quantitative numerical data obtained by the p‐version finite element method.

The mathematical analysis establishes an asymptotic expansion for the eigen‐frequencies in power series of the thickness parameter. Such results are new for orthotropic materials and for the Reissner–Mindlin model. The 3‐D and R–M asymptotics have a common first term but differ in their second terms.

Numerical experiments for clamped plates show that for isotropic materials and relatively thin plates the Reissner–Mindlin eigen‐frequencies provide a good approximation to the three‐dimensional eigen‐frequencies. However, for some anisotropic materials this is no longer the case, and relative errors of the order of 30 per cent are obtained even for relatively thin plates. Moreover, we showed that no shear correction factor is known to be optimal in the sense that it provides the best approximation of the R–M eigen‐frequencies to their 3‐D counterparts uniformly (for all relevant thicknesses range). Copyright © 2002 John Wiley & Sons, Ltd.
Effective circle‐construction algorithms for minimizing the wavelength requirement in WDM rings
Authors: Zhu Guangyu , Yuan Fei , Ghafouri‐Shiraz H.
Published: September 2002

Circle constructions can find many applications in the system design phase of WDM ring networks to optimize system performance, while still efficiently utilizing the network resources under consideration (e.g., total number of wavelengths or transceivers). In this letter, we present a series of matrix‐based circle‐construction algorithms to minimize the number of required wavelengths in both unidirectional and bidirectional rings under an arbitrary traffic pattern. A Matlab implementation of the algorithms can effectively generate the optimum design solution in terms of the total cost on wavelengths. Thus, it ensures that the channel bandwidth and I/O capacity in the WDM rings are utilized most efficiently. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 221–225, 2001.
Small printed‐wing antenna suitable for wireless handset terminals
Authors: Kan H. K. , Waterhouse R. B.
Published: September 2002

A novel, small winged microstrip patch antenna incorporating a single shorting post is introduced. The proposed antenna is significantly smaller than a conventional shorted patch antenna, and is therefore very suited to wireless communication handsets where limited antenna size is a premium. Importantly, the antenna is easy to develop. An integrated version of the proposed antenna on a standard communication handset chassisep is also presented, and its performance is compliant with most cordless systems requirements. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 226–229, 2001.
A double‐folded, capacitive‐fed, cavity‐backed microstrip antenna
Authors: Ooi B. L.
Published: September 2002

A novel, folded, capacitive‐fed microstrip antenna with a length of λ/3 and placed over a cavity backing is proposed. Compared to the small rectangular patch antenna of Luk, our proposed antenna has a large impedance bandwidth of 20.1%. The cross‐polarization level is ∼−17 dB. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 240–241, 2001.
FDTD design of bifilar and quadrifilar truncated spherical helical antennas
Authors: Yang Shiwen , Tan Soon Hie , Xia Jun
Published: September 2002

The radiation characteristics of bifilar and quadrifilar truncated spherical helix antennas are analyzed using the FDTD method. Special attention is paid to the generation of a circularly polarized wave over a wide region above the antenna. By introducing the multiarm structure and changing the feeding geometry, the proposed antennas are capable of providing a symmetric, circularly polarized, broad‐beam radiation pattern, as well as a conical radiation pattern. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 246–249, 2001.
A small‐signal equivalent‐circuit model of quantum‐well lasers based on three‐level rate equations
Authors: Jianjun Gao , Baoxin Gao , Chunguang Liang
Published: September 2002

An intrinsic equivalent‐circuit model for quantum‐well lasers is presented. The model is based on the three‐level rate equations, and includes the carrier transport effects and the role of the gateway state at the quantum well. The simulation results of the frequency response are compared with experimentally obtained data, and agreement is obtained consistently on separate confinement heterostructures (SCHs) of different sizes. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 270–271, 2001.
Quick derivation of high‐power thermal resistance values of HBTs using an existing measurement technique and a theoretical formula
Authors: Tan C. L. , Hui P. , Yan Beiping , Wang Hong , Zheng Haiqun , Yang Hong , Radhakrishnan K.
Published: September 2002

A method is presented for the quick derivation of high‐power thermal resistance values using an existing measurement technique and a theoretical formula. It first derives the low‐power thermal resistance value, and then substitutes this value into the general form for the dependence of thermal resistance derived using the Kirchhoff transformation. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 287–289, 2001.
Comment on “On the Matching Conditions of Different PML Schemes Applied to Multilayer Isotropic Dielectric Media”
Authors: Gedney Stephen D.
Published: September 2002

The focus of this comment is to correct potential misconceptions regarding the application of perfectly matched layer (PML) absorbing media to terminating inhomogeneous media within the finite‐difference time‐domain (FDTD) method. Initially, it is demonstrated that the PML is material independent by nature. That is, by specifying the constitutive parameters to be independent of the host material medium, both the split‐field form and the anisotropic form (or unsplit form) of the PML are materially independent. It is then demonstrated that the split‐field and nonsplit‐field forms of the “materially independent PML” (MIPML) proposed earlier are identical to Berenger's split‐field PML and the anisotropic PML formulations, respectively, after a simple scaling of the conductivity by a constant. While this validates the MIPML, it also illustrates that the MIPML is a subset of previously proven PML methods. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 289–291, 2001.
Conformal proton radiation treatment for retroperitoneal neuroblastoma: Introduction of a novel technique
Authors: Hug Eugen B. , Nevinny‐Stickel Meinhard , Fuss Martin , Miller Daniel W. , Schaefer Rosemary A. , Slater Jerry D.
Published: September 2002

Background

Postoperative irradiation for locoregionally advanced neuroblastoma requires coverage of the paraspinal retroperitoneum. The proximity of both kidneys and the liver, and a more complex target configuration, can pose a dosimetric challenge for conventional X‐ray treatment and intraoperative irradiation. We utilized proton radiation therapy (PRT) to reduce dose to uninvolved kidneys, liver, intestine, and spinal cord.

Procedure

A 4‐year‐old male underwent PRT for neuroblastoma of the right adrenal gland, following chemotherapy and delayed surgical resection. Clinical target volume (CTV), boost volume, and normal structures were outlined on the 3D treatment planning CT scan. The patient received 25.2 CGE (cobalt Gray equivalent) to the CTV and 34.2 CGE to the boost region, using 1.8 CGE per fraction, five treatments per week. Dose‐volume histograms (DVHs) were obtained for target and nontarget structures.

Results

The 95% isodose volume enclosed CTV and boost volumes. The dose to 50% of the ipsilateral kidney, with tumor involvement of the medial renal surface, was ≤ 16 CGE (47% of prescribed total dose). Doses to 50% and 20% of the contralateral kidney in close proximity to deep left‐side, paraspinal soft tissue involvement were restricted to 1 CGE and 10 CGE, respectively. Eighty percent of the liver received 27 CGE (80% of prescribed dose). Using a patch technique, unique to charged particle therapy, the spinal cord was almost completely spared during boost volume irradiation.

Conclusions

PRT can achieve excellent dose conformity for advanced retroperitoneal, paraspinal lesions, while respecting normal tissue tolerance levels. Med. Pediatr. Oncol. 37:36–41, 2001. © 2001 Wiley‐Liss, Inc.
Assignment of the 1H and 13C NMR spectra, sequence and conformation of the synthetic pentasaccharide SanOrg34006 and its precursors
Authors: Bootsma Judica , Wagenaars Gerard , Dreef Erik , Hout Floris , Kellenbach Edwin
Published: September 2002

Proton and carbon chemical shift data and proton–proton coupling constants of the synthetic antithrombotic pentasaccharide SanOrg34006 and its synthetic precursors are reported. Long‐range heteronuclear correlation experiments allow the determination of the substitution pattern of the protecting groups in the precursor molecules. Also, the sequence of the oligosaccharide was confirmed this way. The conformation of the α‐L‐iduronic acid moiety was studied by the analysis of the 3J(1H,1H) coupling constants. Copyright © 2001 John Wiley & Sons, Ltd.
Tissue inhibitor of matrix metalloproteinase‐3 expression in the mouse uterus during implantation and artificially induced decidualization
Authors: Bany B.M. , Schultz G.A.
Published: September 2002

During implantation in mice, tissue inhibitor of matrix metalloproteinases‐3 is believed to play a key role in inhibiting matrix metalloproteinase activity associated with embryo invasion and tissue remodeling. The first objective of this study was to quantitatively compare the steady‐state mRNA levels of tissue inhibitors of matrix metalloproteinases between segments of the mouse uterus undergoing decidualization compared to those that are not during early pregnancy plus oil‐induced decidualization. Steady‐state tissue inhibitor of metalloproteinase‐3 mRNA levels were significantly greater in implantation compared to interimplantation areas on days 6 and 7 of pregnancy and in stimulated compared to nonstimulated uterine horns at 48 and 72 hr after artificial induction of decidualization. Steady‐state tissue inhibitor of metalloproteinase‐1 mRNA levels were significantly greater in implantation compared to interimplantation areas on days 5–8 of pregnancy and in stimulated compared to nonstimulated uterine horns at 24, 48, and 72 hr after oil stimulation. Therefore, the steady‐state mRNA levels of tissue inhibitors of metalloproteinase‐1 and ‐3 increased in the uterus during decidualization. The second objective of this study was to determine if transforming growth factor‐β1 influences tissue inhibitors of metalloproteinase mRNA concentrations in mouse endometrial stromal cells. As determined by Northern blot analyses, transforming growth factor β1 significantly increased tissue inhibitors of matrix metalloproteinases‐1 and ‐3 mRNA levels in cultured mouse endometrial stromal cells isolated from uteri sensitized for decidualization. On the other hand, interleukin‐1, epidermal growth factor, and leukemia inhibitory factor had no effect. The results of this study further characterize the tissue inhibitor of metalloproteinase expression in the uterus during implantation and artificially induced decidualization and the potential control of their expression in the stroma by transforming growth factor. Mol. Reprod. Dev. 59:159–167, 2001. © 2001 Wiley‐Liss, Inc.
In vivo BOLD contrast MRI mapping of subcutaneous vascular function and maturation: Validation by intravital microscopy
Authors: Neeman Michal , Dafni Hagit , Bukhari Omar , Braun Rod D. , Dewhirst Mark W.
Published: September 2002

Bold contrast MRI was applied for mapping vascular maturation in tumor‐ and wound‐induced skin angiogenesis using the response of mature vessels to hypercapnia (inhalation of air vs. air 5% CO2) and the response of all vessels to hyperoxia (air 5% CO2 vs. oxygen 5% CO2 (carbogen)). MRI signal enhancement with hypercapnia was reduced in centered vs. linear phase encoding, suggesting increased blood flow. However, intravital microscopy demonstrated constriction of arterioles and reduced flux and density of red blood cells in mature capillaries with hypercapnia, with no change in the diameter of wound‐induced neovasculature. The discrepancy in flow between MRI and intravital microscopy is consistent with increased plasma flow and reduced hematocrit. Hyperoxia resulted in increased blood oxygenation and constriction of all vessels. These results provide a hemodynamic explanation for the selective registration of MRI response to hypercapnia with mature vessels and the response to hyperoxia with total vascular function. Magn Reson Med 45:887–898, 2001. © 2001 Wiley‐Liss, Inc.
Dysprosium‐bearing red cells as potential transverse relaxation agents for MRI
Authors: Johnson Kevin M. , Tao Jing Zang , Kennan Richard P. , Gore John C.
Published: September 2002

The cytosol of intact human red blood cells was loaded with 28.1 ± 3.4 mM of dysprosium DTPA‐BMA using a hypoosmotic technique. When loaded cells were diluted with saline and control cells to give an average dysprosium concentration of 3.3 ± 0.5 mM, the transverse relaxation rate constants R and R2 increased. R increased from 7.5 ± 0.9 sec−1 to 356 ± 50 sec−1, and R2 increased from 7.4 ± 0.7 sec–1 to 148 ± 40 sec−1. After lysing, R was 6.0 ± 0.6 sec−1 in the control and 13.4 ± 1.5 sec−1 in the mixture; R2 was 6.4 ± 1.1 sec−1 and 9.8 ± 2.4 sec−1, respectively. Thus, the relaxivity effects were enhanced by sequestration of the dysprosium within intact red cells, and this effect was lost after lysis. At a circulating whole‐blood concentration of 0.81 ± 0.15 mM in rats, the liver signal intensity dropped 29.9% ± 3.7% and kidney signal intensity dropped 19.4% ± 8.7%. Dysprosium‐loaded cells might be useful in the study of perfusion and tissue blood volume. Magn Reson Med 45:920–923, 2001. © 2001 Wiley‐Liss, Inc.
The agrin/muscle‐specific kinase pathway: New targets for autoimmune and genetic disorders at the neuromuscular junction
Authors: Liyanage Yohan , Hoch Werner , Beeson David , Vincent Angela
Published: September 2002

The increasing understanding of the structural complexity of the neuromuscular junction (NMJ), and the processes that are important in its development, suggests many possible new disease targets. Here, we summarize briefly the genetic and autoimmune disorders that affect neuromuscular transmission, and the identified targets, including new evidence that antibodies to muscle‐specific receptor tyrosine kinase (MuSK) are involved in the pathogenesis of acetylcholine receptor (AChR) antibody–negative myasthenia gravis. We then review the development of the NMJ, focusing on the important roles of nerve‐derived agrin and MuSK in clustering of AChRs and other essential components of the NMJ. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 4–16, 2002
Effects of the benzodiazepine tetrazepam on rat diaphragm tetanic contractions
Authors: Piek Tom , van Weeren‐Kramer Janneke , van Wilgenburg Henk , Zeegers Arie , Leeuwin Remy S.
Published: September 2002

A saturated solution of tetrazepam in Krebs‐Ringer did not affect the contraction force of the isolated diaphragm in vitro significantly during indirect stimulation at frequencies from 10 to 50 Hz. An overdose of crystalline tetrazepam, added to the bath (Krebs‐Ringer solution) induced an increase of contraction force of the tetanus at various frequencies, with a maximum at 30 Hz, up to 400% ± 30 (n=4) of the control value. It is suggested that the solubility of tetrazepam in Krebs‐Ringer solution is increased by substances released from the muscle. At a concentration of 10–4 M tetrazepam in Tween 80 (final concentration 0.25%), a comparable increase in contraction force occurred at indirect stimulation with 30 Hz. The maxima occurred at about one hour after exposure and were followed by a gradual decrease. At a stimulation frequency of 70 Hz, a gradual decrease in contraction force of 68% (± 3) (n=4) occurred after 2.5 hours, while the control force (in Tween 80, 0.25% ‐ in order to enhance the solubility of tetrazepam) decreased with 18% (± 6). At a concentration of 10–5 M, tetrazepam caused an increase in contraction force to about 150% (± 6) at 30 Hz (first stimulation of each cycle), and significant decrease in contraction force of about 20% at 70 Hz. At direct stimulation with 30 Hz the tetanic contraction force was increased as well by 10–4 M tetrazepam, whereas at 10–3 M of the benzodiazepine the force was depressed. These in vitro results fit with the muscle relaxation mentioned in a case report (two times 100 mg dose) in relation to 50 mg doses resulting in plasma level with a peak of about 2×10–6 M reported earlier (1). The results of the study tentatively suggest that the use of tetrazepam in the appropriate dose is more favourable than using diazepam in treating spasms associated with lumbago.
Effects of flunarizine on cadmium‐induced Purkinje cell loss in rats
Authors: Genç Hayri , Bağirici Faruk , Çakir Arzu , Demi̇r Şerif , Tan Faruk
Published: September 2002

The effects of the calcium channel blocker flunarizine on cadmium‐induced Purkinje cell loss in the cerebellum of rats were investigated. Rats were divided into three groups: control, cadmium, and cadmium+flunarizine. Saline was administered intracortically to the first group, cadmium sulphate (0.0021 mg/kg) to the second group, and cadmium sulphate (0.0021 mg/kg) and flunarizine (1 mg/kg) to the third group. All rats were observed for 1 week, but only the rats in the third group were injected with flunarizine (10 mg/kg/day, i.p.) during this period. One week later, all rats were perfused intracardially. Series of frontal sections from the cerebellum were stained with thionin. Purkinje cells were counted at × 400 magnification under a light microscope. Purkinje cell density was 20.62 ± 0.68/mm (average ± SD) in the right hemisphere and 20.56 ± 0.79/mm in the left hemisphere of the control group; 14.23 ± 0.34/mm in the right hemisphere and 14.17 ± 0.44/mm in the left hemisphere of the cadmium group; and 18.46 ± 0.59/mm in right hemisphere and 17.76 ± 0.84/mm in left hemisphere of the cadmium+flunarizine group. The results suggest that flunarizine may attenuate Purkinje cell death caused by cadmium (P < 0.05).
Conformational analysis of 2‐bromocyclohexanone. A combined NMR, IR, solvation and theoretical approach
Authors: Freitas Matheus P. , Rittner Roberto , Tormena Cláudio F. , Abraham Raymond J.
Published: September 2002

An improved method of conformational analysis using 1H and 13C NMR, IR, theoretical calculations and solvation theory is reported for 2‐bromocyclohexanone, used here as a model compound. The solvent dependence of the 3JHH, 1JCH and 1JCD NMR coupling constants and the associated changes in the IR first overtone carbonyl band intensities together with theoretical calculations allow the direct determination of the conformational equilibria without recourse to model compounds. Calculations with the Gaussian 98 program at the HF/6–31 g(d,p) and B3LYP/6–31 + g(d,p) levels together with solvation theory gave the conformer free energy difference (Eeq − Eax) in different solvents. The observed couplings, when analyzed by solvation theory and utilizing DFT geometries, gave a value of Eeq − Eax of 1.15 kcal mol−1 in the vapor phase, decreasing to 0.6 kcal mol−1 in CCl4 and to −0.5 kcal mol−1 in DMSO solution (1 kcal = 4.184 kJ). The axial percentage changes from 74% (in CCl4) to 30% (in DMSO), and these are in good agreement with infrared data (νCO, first overtone), despite the uncertainties of the latter method. The results illustrate the advantages of the joint application of these techniques, which represents an improved approach to the study of the conformational equilibria of substituted cyclohexanones. Copyright © 2001 John Wiley & Sons, Ltd.
Kinetics of ‘initial burst’ in the solid–liquid phase‐transfer catalysis. Nucleophilic substitution of 2‐octyl mesylate with potassium bromide
Authors: Yufit S. S. , Zinovyev S. S.
Published: September 2002

The SN2 substitution of 2‐octyl mesylate with solid KBr under the conditions of phase‐transfer catalysis was studied kinetically using the model approach of ‘initial burst.’ It is suggested that such kinetics reflect the contribution of mass transfer and surface poisoning. The proposed model is used to explain the influences of catalyst, solvent, stirring speed, activation and agitation effects. The mechanistic scheme suggests that the reaction is described by two separate kinetic stages, one of which reflects the intrinsic rate‐limited step and the other the mass transfer‐controlled step. Copyright © 2001 John Wiley & Sons, Ltd.
Graft copolymerization induced by thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid in bulk
Authors: Kasashima Yoshio , Shinoda Koichi , Matsushima Hiroshi , Shitagaki Satoko , Inoki Mari , Akutsu Fumihiko , Shimura Tadashi , Tsuchiya Masaomi
Published: September 2002

Thermal reactions of the binary alkali salts of poly(carboxylic acid)–brominated carboxylic acid such as sodium or potassium poly(4‐vinylbenzoate)‐2‐bromopropanoate [Na or K (PVBA‐2‐BPA)] in bulk were investigated. A methanol solution of binary acids was prepared by fixing the molar ratio of the repeating unit of polymeric acid to the fraction of brominated carboxylic acid. The binary salts were prepared by the neutralization of the binary acid solution. The product of the thermal reaction followed by esterification was identified as a graft copolymer containing PVBA in the main chain and polylactic acid in the side chain. The reaction of 1/15 K (PVBA‐2‐BPA) at 120 °C for 2 h yielded the highest percentage of grafting (300%). The grafting proceeded gradually for the initial 2 h and then somewhat. Reactivity of the K salt was higher than that of the corresponding Na salt. The thermal reaction of 1/10 K [polymethacrylate‐2‐BPA (PMA‐2‐BPA)] at 120 °C for 2 h also yielded a graft copolymer, and the percentage of grafting was 300%. However, reaction temperatures higher than 120 °C caused homopolycondensation of K 2‐BPA prior to grafting, and homopolycondensation occurred prior to grafting in the reaction with Na (PMA‐2‐BPA). © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1877–1885, 2001
Vapor deposition polymerization of heteroatom‐bridged [2.2]paracyclophanes: 1,9‐dithia[2.2]paracyclophane and 1,9‐dithia[2.2]paracyclophane‐1,1,9,9‐tetroxide
Authors: Itoh Takahito , Ohtake Shizuhiko , Mitsuda Yukihiro , Kubo Masataka
Published: September 2002

1,9‐Dithia[2.2]paracyclophane‐1,1,9,9‐tetroxide (3) was synthesized as white needles in a high yield from 1,9‐dithia[2.2]paracyclophane (2) by oxidation with m‐chloroperbenzoic acid, and its molecular structure was determined with single‐crystal X‐ray diffraction analysis. Vapor deposition polymerizations of 2 and 3 gave amorphous and brittle polymer films along with considerable amounts of nonpolymeric byproducts. A polymer film from 2 was a copolymer of p‐(phenylene‐methylenesulfide) with p‐(phenylene‐methylene) units, and a polymer film from 3 was a homopolymer of p‐(phenylene‐methylene) units with head‐to‐tail, head‐to‐head, and tail‐to‐tail placements. The elimination of sulfur atoms in 2 and sulfone units in 3 took place during their pyrolysis reactions. Plausible mechanisms for vapor deposition polymerizations of both cyclophanes are proposed. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1892–1900, 2001
Triisobutylaluminum as cocatalyst for zirconocenes. II. Triisobutylaluminum as a component of a cocatalyst system and as an effective cocatalyst for olefin polymerization derived from dimethylated zirconocenes
Authors: Panin A. N. , Dzhabieva Z. M. , Nedorezova P. M. , Tsvetkova V. I. , Saratovskikh S. L. , Babkina O. N. , Bravaya N. M.
Published: September 2002

An investigation of the catalytic behavior of the dimethylated zirconocenes Me2SiCp*NtBuZrMe2 [Cp* = C5(CH3)4; 1Me], Me2SiCp2ZrMe2 (2Me), Cp2ZrMe2 (3Me), Ind2ZrMe2 (4Me), Me2SiInd2ZrMe2 (5Me), Et(2‐MeInd)2ZrMe2 (6Me), and Me2Si(2‐MeInd)2ZrMe2 (7Me) with the combined activator triisobutylaluminum (TIBA)/CPh3B(C6F5)4 (Al/Zr = 250; B/Zr = 1) in ethylene polymerizations at increased monomer pressures (5–11 bar, 30 °C) was carried out. Sterically opened zirconocenes in ternary catalysts gave rise to active species effective in the formation of low molecular weight polyethylenes (PEs). These active species tended to increase the PE molecular weight [1Me (2100) < 2Me (20,000) < 5Me (89,000) < 3Me (94,500)] under similar conditions. PE obtained with 4Me showed a bimodal gel permeation chromatography curve with a 64% peak area [weight‐average molecular weight (Mw) = 43,000] and a 36% peak area (Mw = 255,000). The increase in sterical demands from the zirconocenes was also demonstrated by the reduction of the chain transfer to monomer, the reinsertion of vinyl‐ended PE chains, and their ability for isomerization. These reactions were most pronounced for the zirconocenes 1Me and 2Me. The active species responsible for the formation of low molecular weight PEs deactivated quickly. The zirconocenes 6Me, 7Me, and (2‐PhInd)2ZrMe2 (8Me) bearing substituent at the 2‐position of the indenyl ring was activated with TIBA alone, yielding active species effective in ethylene and propylene polymerizations. PEs formed with 6Me–8Me complexes activated with TIBA had high molecular weights. An increase in the Al/Zr ratio in the catalytic system 8Me/TIBA from 50 to 300 led to an enhancement of the molecular weight of polypropylene (PP) samples from oligomeric products to an viscosity‐average molecular weight of 220,000. The increase in the molecular weights of PPs with an increase in the propylene concentration was also observed. An analysis of the catalytic performance of the 8Me/TIBA system showed first‐order dependency of the initial polymerization rates on the TIBA concentration and close to second‐order dependency on propylene. The second‐order dependency on the monomer concentration is explained in terms of the monomer participation in the initiation step of the polymerization reaction. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1915–1930, 2001
Phase structure and thermomechanical properties of primary and tertiary amine‐cured epoxy/silica hybrids
Authors: Ochi M. , Takahashi R.
Published: September 2002

Several kinds of organic–inorganic hybrids were synthesized from an epoxy resin and a silane alkoxide with a primary amine‐type curing agent or tertiary amine curing catalyst. In the hybrid systems cured with the primary amine‐type curing agent, the storage modulus in the high‐temperature region increased, and the peak area of the tan δ curve decreased. Moreover, the mechanical properties were improved by the hybridization of small amounts of the silica network. However, these phenomena were not observed in the hybrid systems cured with the tertiary amine catalyst. The differences in the network structures of the hybrid materials with the different curing processes were characterized with Fourier transform infrared (FTIR). In the hybrid systems cured with the primary amine‐type curing agent, FTIR results showed the formation of a covalent bond between silanol and hydroxyl groups that were generated by the reaction of an epoxy group with an active hydrogen of the primary amine. However, this phenomenon was not observed in the hybrids cured with the tertiary amine. The hybrids with the primary amine showed a homogeneous microstructure in transmission electron microscopy observations, although the hybrids cured with the tertiary amine showed a heterogeneous structure. These results mean that the differences in the interactions between the organic and inorganic phases significantly affect the properties and microstructures of the resultant composites. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1071–1084, 2001
A comparison of Portuguese and American patients with hematological malignancies: a cross‐cultural survey of health‐related quality of life
Authors: Forjaz Maria João , Guarnaccia Charles A.
Published: September 2002

This study investigates health‐related quality of life (QoL) differences between 98 Portuguese and 109 US American outpatients with hematological malignancies. These two national groups of patients were characterized in terms of patients' QoL, and socio‐demographic and clinical variables. Differences were found for several socio‐demographic variables (race, marital and job status, urban residence, diagnosis, age, education, and household size). Portuguese patients reported better physical functioning, less bodily pain, more vitality, better social functioning, and better general QoL [as measured by Functional Living Index—Cancer (FLIC) total score] than American patients. Results were independent of demographic differences or mode of questionnaire administration. Copyright © 2001 John Wiley & Sons, Ltd.
Differential expression of c‐erb B2/neu, epidermal growth factor receptor, cytokeratin 8, and the prostatic steroid‐binding protein gene in rat ventral prostate during postnatal development
Authors: Pisters Louis L. , Wang Xiao‐Huai , Chung Leland W.K. , Hsieh Jer Tsong
Published: September 2002

BACKGROUND

The development and progression of prostate neoplasia may recapitulate the early developmental pattern of expression of genes in the prostate. The study of prostate development may, therefore, provide insights into the molecular mechanisms important in prostate neoplasia and reveal new markers.

METHODS

We compared postnatal expression of four genes: neu and epidermal growth factor receptor genes (EGFR), androgen‐upregulated in the ventral prostate of adult rats (C‐3), and androgen‐repressed (CK8) in Sprague–Dawley rats. In situ hybridization was performed on prostate frozen sections collected on postnatal days 1, 5, 10, 15, 20, 30, and 60 from five rats per day. Staining intensities for antisense probes specific for each gene were determined relative to day 1 intensity.

RESULTS

Growth factor receptors including neu and EGFR may be coordinately regulated in the basal‐cell population during prostate development. CK8 and C‐3 show evidence of similar androgen regulation during development.

CONCLUSIONS

CK8 and C‐3 have distinct patterns of expression in the postnatal period of development and these genes may be good markers of differentiation. Both neu and EGFR may be involved in androgen‐independent growth of basal cell population in prostate. Prostate 47:164–171, 2001. © 2001 Wiley‐Liss, Inc.
Human rhabdosphincter cell culture: A model for videomicroscopy of cell contractions
Authors: Corvin Stefan , Strasser Hannes , Boesch Simone T. , Bartsch Georg , Klocker Helmut
Published: September 2002

BACKGROUND

Physiology of the human rhabdosphincter and its innervation are still a subject to controversy. A better understanding of rhabdosphincter function and anatomy might help to solve important urological problems like urinary incontinence. It was the aim of the present study to develop a human sphincter cell culture model for investigation of contraction mechanisms in vitro.

METHODS AND RESULTS

Cells were isolated from human rhabdosphincter tissue obtained from prostatectomy and cystoprostatectomy specimens. Cultured cells expressed typical features of striated muscle cells. By means of videomicroscopy with a time lapse videosystem cell contractions could be documented. Under control conditions without any contractile stimulant 8% of the cells were seen to contract. Cholinergic stimulation with 10 mM of acetylcholine induced a significant increase in contraction rate to 49%.

CONCLUSIONS

These results demonstrate that cholinergic stimulation triggers contraction of cultured human rhabdosphincter cells. This model might help to understand external urethral sphincter physiology and to establish new therapies for the treatment of sphincter dysfunctions. Prostate 47:189–193, 2001. © 2001 Wiley‐Liss, Inc.
A modified extraction and clean‐up procedure for the detection and determination of parathion‐methyl and chlorpyrifos residues in tea
Authors: Shanker Adarsh , Sood Chitra , Kumar Vipin , Ravindranath Srigripuram Desikachar
Published: September 2002

Recent advances in methodology and instrumentation have made possible the detection and determination of pesticides at µg kg−1 (ppb) levels. The sensitivity of a method of analysis depends greatly on the efficient extraction of the pesticide and the subsequent clean‐up of the extract. The extract from green tea leaves is a mixture of aroma components, polyphenols and caffeine. The preparation of made tea from green tea leaves adds to this complexity by concentrating these co‐extractives. Conventional clean‐up techniques provide poor recoveries for parathion‐methyl and chlorpyrifos from both green tea leaves and made tea. This arises from interference by caffeine during gas chromatography, as it has a similar retention time to the two pesticides and peaks overlap. A modification to the protocol based on a solvent partitioning process using dichloromethane and subsequent washing of the extracts with warm water removed the caffeine, and pigments were removed by column chromatography. Recoveries ranging from 80 to 90% were then obtained for both pesticides.

© 2001 Society of Chemical Industry
On the practical use of weld improvement methods
Authors: Nussbaumer A , Imhof D
Published: September 2002

Many laboratory studies have shown the beneficial effects of weld improvement methods on the fatigue strength of welded details. However, no structural codes systematically include weld improvement methods in detail classification. The purpose of this paper is to discuss the possibilities of using these methods in practice on either new or existing structures. This paper provides the reader with practical rules for designing and computing the fatigue strength of improved welded joints. A computation method based on the concept of effective stress range is introduced to model the effects of peening improvement methods on fatigue strength. For the most popular improvement methods, the fatigue strength of improved details can be deduced from the extensive existing database of full‐scale test results. However, for non‐classified details, or when fabrication and improvement processes require validation, testing of the improved details is the only method available to guarantee the fatigue strength of a particular detail. In this paper a recent application of validation through testing in the case of longitudinal attachments is described.
Design of industrial storage racks
Authors: Peköz Teoman , Rao Kotha
Published: September 2002

The current design provisions for steel industrial storage racks are summarized and a progress report on a current Cornell University Research project is given.
Prediction of bending strength of long corrugated boxes
Authors: Panyarjun Oranis , Burgess Gary
Published: September 2002

Long corrugated boxes were supported at both ends and bent by a concentrated force applied at the middle. Boxes with different lengths, cross‐sectional shapes, flute directions and board strengths were tested, using a standard compression tester with a fixed platen in accordance with ASTM D‐642. An equation was developed to relate compression strength to the various properties of the box. The correlation coefficient R2 for the fit to actual data was about 0.4. Boxes having the flutes run around the box had a 20% higher compression strength than with horizontal flutes. The most significant factor was found to be the board edge crush strength. The results suggest that failure of boxes in bending is due to localized crushing at the point of application of the load, rather than whole‐box collapse. Copyright © 2001 John Wiley & Sons, Ltd.