bluuebunny/crossref_metadata_2025 huggingface dataset:
Microtopography as a factor in the degradation of Vertisols in central India
Authors: Vaidya P. H. , Pal D. K.
Published: October 2002

Earlier studies on soil degradation in Vertisols of the Purna Valley of central India indicated that the semiarid climate characterized by a mean annual rainfall (MAR) of 875 mm and a tropustic moisture regime is responsible for the development of calcareous sodic soils. Recent observations, however, indicate that in the adjacent east upland of the Purna Valley, namely in the Pedhi Watershed, Vertisols have drainage problems, although the area receives a higher MAR than the Purna Valley, the total MAR being 975 mm. The Pedhi Watershed covers an area of 44 321 ha, and is characterized by a tropustic moisture regime and a hyperthermic temperature regime.

Vertisols of the Pedhi Watershed are deep, calcareous, clayey and very dark greyish‐brown to dark yellowish‐brown in colour. Vertisols occur on both microhigh (MH) and microlow (ML) positions. The distance between the MH and ML positions is approximately 6 km and the elevation difference is 0.5–5 m. Cracks > 1 cm wide extend down to the slickenside zones in soils of ML whereas they cut these zones in some soils in MH positions. The soils of the MH positions are strongly alkaline and those of ML are mildly alkaline.

The present study attempts to relate the distinctly different morphological and chemical properties of Vertisols in the MH and ML positions to pinpoint the prime factor responsible for the impairment of drainage on the basis of physical, chemical, mineralogical and micromorphological data. These data were obtained from 13 Vertisol pedons of methodically selected sites in the Pedhi Watershed.

Despite their similar coefficient of linear extensibility (COLE), volumetric shrinkage potential (VSP), clay contents and amounts of fine smectite clay, the plasmic fabric of the slickenside horizons in soils of ML is porostriated, whereas in soils of MH it is stipple speckled to mosaic speckled, indicating weak plasma separation. The soils have both pedogenic and non‐pedogenic calcium carbonates (CaCO3). The semiarid climate induces the precipitation of CaCO3 with a concomitant development of subsoil sodicity. The degree of development of sodicity (Exchangeable sodium percentage (ESP) ≥ 5) is more in soils of MH as evidenced by the higher amount of pedogenic CaCO3 (PC). The lack of water in soils of MH position is the reason for weak swelling of smectite, for larger amounts of PC, for higher alkalinity and sodicity, and for cracks cutting through the slickenside zones. Formation of sodic Vertisols in MH alongside non‐sodic Vertisols in ML positions is a unique phenomenon. It develops because of microtopographic differences which modify distribution of water across the landscape and facilitate greater penetration of rainwater in ML positions. The development of sodicity due to microtopographic differences assumes a great importance when a future land resource management programme on Vertisols in the higher MAR zone of overall a semiarid climate is considered. Copyright © 2002 John Wiley & Sons, Ltd.
Mass spectra of copolymers
Authors: Montaudo Maurizio S.
Published: October 2002

I.
Introduction
108

  II.
Structural Analysis
109

 III.
Copolymer Composition
111

A. Composition by the Direct Method
111

B. Composition by the Method Based on Statistics
111

C. Copolymer Composition by the Hard‐Ionization Method
113

  IV.
Copolymer Sequence
114

   V.
Molar Mass Determination
115

  VI.
MS as a Detector for Liquid Chromatography
116

 VII.
Composition Drift and the Compositional Distribution Histogram
120

VIII.
Quantitation and Methods to Correct Mass Spectral Intensities
121

  IX.
Copolymer Mixtures and Blends
122

   X.
Copolymers Obtained by Specific Synthetic Routes
123

A. Copolymers Produced by Enzymes or Occurring in Nature
123

B. Block Copolymers
125

C. Random Addition Copolymers
126

D. Random Condensation Copolymers
128

  XI.
Summary and Outlook
133

Acknowledgments
134

References
135

Recent and older literature (covering the last 12–13 years) in the field of mass spectra of random and block copolymers is reviewed. A detailed description is given of the information on copolymer properties that can be recovered from the analysis of the low‐mass region of the spectrum (the region below 500 Da) and the high‐mass region. The features of mass spectra of copolymers obtained by different synthetic routes are discussed, such as free radical, condensation, ring‐chain equilibration, microbial synthesis, ring‐opening, simple anionic, cationic, Ziegler‐Natta, and/or metallocene catalysis, along with some random and block copolymers that occur in Nature. The emphasis is on copolymer composition and average molar mass determination, and on the benefits of coupling mass spectrometry (MS) with separation techniques such as size‐exclusion chromatography (SEC) and high performance liquid chromatography (HPLC). © 2002 Wiley Periodicals, Inc., Mass Spec Rev 21:108–144, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mas.10021
Depression leading to attempted suicide after bilateral subthalamic nucleus stimulation for Parkinson's disease
Authors: Doshi Paresh K. , Chhaya Niraj , Bhatt Mohit H.
Published: October 2002

Subthalamic nucleus stimulation is emerging as an effective surgical therapy for Parkinson's disease. It is considered to be a safe procedure with little morbidity, the most common complications being intracranial haemorrhage and hardware failure. We report on three cases of depression, one of whom attempted suicide after bilateral subthalamic nucleus stimulation. © 2002 Movement Disorder Society
Effect of medication on EMG patterns in individuals with Parkinson's disease
Authors: Robichaud Julie A. , Pfann Kerstin D. , Comella Cynthia L. , Corcos Daniel M.
Published: October 2002

Individuals with Parkinson's disease show dramatic improvements in their ability to move when medicated. However, the neural cause of this improvement is unclear. One hypothesis is that neural activation patterns, as measured by surface electromyography (EMG), are normalized by medication. We tested this hypothesis by investigating the effect of medication on the electromyographic (EMG) patterns recorded when individuals with idiopathic Parkinson's disease performed elbow flexion movements over three movement distances while off and on antiparkinsonian medication. When the subjects were off medication, they lacked the ability to modulate the agonist EMG burst duration with changes in movement distance. The ability to modulate agonist EMG burst duration is characteristic of the EMG patterns observed in healthy subjects. Also, multiple agonist bursts were exhibited during the acceleration phase. As expected, medication diminished the clinical signs of Parkinson's disease, increased movement speed, and increased the magnitude of the first agonist burst. Medication did not restore agonist burst duration modulation with movement distance, did not change the frequency of agonist bursting, and did not alter the timing of the antagonist activation. These results show that medication does not alter the temporal profile of EMG activation. © 2002 Movement Disorder Society
Freezing of gait in postmortem‐confirmed atypical parkinsonism
Authors: Müller Jörg , Seppi Klaus , Stefanova Nadia , Poewe Werner , Litvan Irene , Wenning Gregor K.
Published: October 2002

The frequency and pathophysiology of freezing of gait (FoG) in atypical parkinsonism is unknown. We analysed the frequency of FoG in postmortem‐confirmed atypical parkinsonian disorders (APD) comprising corticobasal degeneration (CBD), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and progressive supranuclear palsy (PSP). Sixty‐six patients with pathologically confirmed APD (CBD, n = 13; DLB, n = 14; MSA, n = 15; PSP, n = 24) formed the basis for a multicenter clinicopathological study. Clinical features at first and last clinical visit were abstracted from patient records on standardized forms following strict instructions. At the first visit (median 36 months after symptom onset), 24% of APD had FoG (CBD, 8%; DLB, 21%; PSP, 25%; MSA, 40%). Logistic regression analysis showed a significant association of FoG and urinary incontinence (P = 0.04) at first visit. At last visit, 47% of APD had FoG (CBD, 25%; PSP, 53%; DLB, 54%; MSA, 54%). Clinicopathological correlation based on routine postmortem examination failed to identify a consistent neuropathological substrate of FoG. This study demonstrates that (1) FoG is common in APD, and (2) urinary incontinence is significantly associated with FoG in these disorders. Whether FoG and urinary incontinence share similar neuropathological substrates remains to be determined by future studies. © 2002 Movement Disorder Society
Improved performance of photonic band‐gap microstripline structures with the use of Chebyshev distributions
Authors: Karmakar Nemai C.
Published: October 2002

Conventional uniform circular‐patterned photonic band gaps (PBGs) have constraints in the broadband passband and stopband performance because of the high ripple heights in S parameters. This Letter suggests a novel configuration with nonuniform dimensions of circular‐patterned PBG to improve both pass‐ and stopband bandwidths and the ripples. The dimensions of the circles are varied proportionally to the relative Chebyshev amplitudes of a 10‐element PBG array, and the dispersion characteristics are analyzed. It is seen that the Chebyshev distribution of the circular‐patterned PBG line produces excellent performance by suppressing ripples and yielding better selectivity at cutoffs. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 1–5, 2002; DOI 10.1002/mop.10212
Measurement of dielectric and radiation losses for flexible circular dielectric waveguides in Q‐band
Authors: Kim Ki Young , Tae Heung‐Sik , Lee Jeong‐Hae
Published: October 2002

Experimental results are presented for the dielectric and radiation losses from flexible circular PTFE waveguides in the Q‐band. The dielectric and radiation losses from rod and tube waveguides were found to depend strongly on the design parameters, such as the operating frequency, area of the dielectric region in the guiding cross sections, and curvature radii of the bending. The dielectric losses from the straight guides showed a relatively good agreement with the theoretical results. The radiation losses with a small curvature radius, which cannot be predicted using current theories, were determined based on the differences between the measured insertion losses and the dielectric losses. The validity of the current results was confirmed based on the fractional power flow ratios in each region of the waveguides. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 000–000, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10529
Effect of temperature on LiMnTi ferrite based microstrip circulator
Authors: Dubey Ashish , Tyagi G. S. , Srivastava G. P. , Badola N. K. , Jain K. K.
Published: October 2002

A conventional three port microstrip junction circulator has been experimentally demonstrated in the X‐band frequency region, by depositing the thin films of Cr‐Cu‐Au over the LiMnTi bulk polycrystalline ferrite substrate. Characteristics of fabricated circulator have been studied by keeping it in the moderate thermal range. Variations in the characteristics of fabricated circulator have been analyzed on the basis of variation of saturation magnetization, dielectric constant and loss tangent of ferrite material with the external atmospheric temperature. Experimental results qualitatively agree with the theoretical ones. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 114–117, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10532
Application of an optical birefringence interferometer to photothermal detection
Authors: Xu X. D. , Kuo P. K. , Zhang S. Y. , Shui X. J. , Zhang Z. N.
Published: October 2002

In this paper a birefringence interferometer is used for detecting both change in reflectivity and surface deformation caused by photothermal effect or thermal waves excited by anyother pump source. The instrument is very simple, with high immunity against noise and sensitivity. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 140–143, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10540
An experimental study of small self‐resonant antennas for wireless applications
Authors: Ali M. , Stuchly S. S. , Caputa K.
Published: October 2002

Two types of self‐resonant antennas, meander and sinusoidal are experimentally characterized. Input impedance, bandwidth, and radiation pattern data for such antennas are given. It is demonstrated that antennas that are 34% shorter than quarter‐wave monopoles and have 3.8 dBi of peak gain can be designed with acceptable bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 143–145, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10541
Application of adaptive local cosine transform to detection and estimation of ultra‐wideband signals through dispersive propagation channels
Authors: Deng Hai , Ling Hao
Published: October 2002

The adaptive local cosine transform (ALCT) is applied to identify the time‐frequency distribution of an ultra‐wideband signal transmitted through a dispersive propagation channel in the presence of noise. The estimated time‐frequency distribution is then used to detect subsequently transmitted signals. Simulation results show the ALCT outperforms the traditional short‐time Fourier transform. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 150–153, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10543
Patch array as artificial magnetic conductors for antenna gain improvement
Authors: Zhang Ying , von Hagen Jürgen , Wiesbeck Werner
Published: October 2002

A patch array is tested as reflector. The reflection coefficient for a plane wave is measured, the findings are explained by the functioning of a single patch. A λ/2 dipole and a 2‐arm spiral antenna are fitted with this reflector. It enhances the gain with the complete structure remaining small. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 172–175, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10548
Line integral representation of physical optics diffraction field from perfectly conducting plates
Authors: Cui Suomin , Ando Makoto
Published: October 2002

An alternative approach for analyzing diffraction field for physical optics (PO) is presented in this paper. This approach separates geometrical optics field and diffraction field from the total field analytically by using field equivalence principle or the divergence theorem and choosing the special surfaces which lie on the reflection and shadow boundaries, and then transfers the surface integral which represents the diffraction field into simple line integral analytically. Two types of representations of PO field lead to the two types of line integral expressions for PO diffraction field. One is very simple and is not reported in the literature to the best knowledge of the authors, and another is identical with available result, which can be considered as alternative derivation of the available result. The proposed approach differs from other high frequency analysis in that it's not asymptotic evaluation of radiation integration, or heuristic or empirical. The superiority of this new analysis is demonstrated numerically. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 206–211, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10559
On the design of polarization‐insensitive semiconductor optical amplifiers
Authors: Wartak M. S. , Weetman P.
Published: October 2002

We have used the 4 × 4 Luttinger–Kohn Hamiltonian to analyse the presence of delta‐strain in quantum well on the polarization properties of semiconductor optical amplifiers. The analysis is performed for a 1.55 μm InGaAsP/InP lattice matched system grown in the [001] direction with and without the electrostatic effects of the carrier charges. The importance of electrostatic effects is indicated. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 227–230, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10564
Are TrueFISP images T2/T1‐weighted?
Authors: Huang Teng‐Yi , Huang Ing‐Jye , Chen Cheng‐Yu , Scheffler Klaus , Chung Hsiao‐Wen , Cheng Hui‐Cheng
Published: October 2002

Images acquired using the TrueFISP technique (true fast imaging with steady‐state precession) are generally believed to exhibit T2/T1‐weighting. In this study, it is demonstrated that with the widely used half‐flip‐angle preparation scheme, approaching the steady state requires a time length comparable to the scan time such that the transient‐state response may dominate the TrueFISP image contrast. Two‐dimensional images of the human brain were obtained using various phase‐encoding matrices to investigate the transient‐state signal behavior. Contrast between gray and white matter was found to change significantly from proton‐density‐ to T2/T1‐weighted as the phase‐encoding matrix size increased, which was in good agreement with theoretical predictions. It is concluded that TrueFISP images in general exhibit T2/T1‐contrast, but should be more appropriately regarded as exhibiting a transient‐state combination of proton‐density and T2/T1 contrast under particular imaging conditions. Interpretation of tissue characteristics from TrueFISP images in clinical practice thus needs to be exercised with caution. Magn Reson Med 48:684–688, 2002. © 2002 Wiley‐Liss, Inc.
Degeneracy in inventory models
Authors: Lau Amy Hing‐Ling , Lau Hon‐Shiang , Pyke David F.
Published: October 2002

In order‐quantity reorder‐point formulations for inventory items where backordering is allowed, some of the more common ways to prevent excessive stockouts in an optimal solution are to impose either a cost per unit short, a cost per stockout occasion, or a target fill rate. We show that these popular formulations, both exact and approximate, can become “degenerate” even with quite plausible parameters. By degeneracy we mean any situation in which the formulation either cannot be solved, leads to nonsensical “optimal” solutions, or becomes equivalent to something substantially simpler. We explain the reasons for the degeneracies, yielding new insight into these models, and we provide practical advice for inventory managers. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 686–705, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10037
Direction of action potential propagation influences calcium increases in distal dendrites of the cricket giant interneurons
Authors: Ogawa Hiroto , Baba Yoshichika , Oka Kotaro
Published: October 2002

To understand the relationship between the propagation direction of action potentials and dendritic Ca2+ elevation, simultaneous measurements of intracellular Ca2+ concentration ([Ca2+]i) and intradendritic membrane potential were performed in the wind‐sensitive giant interneurons of the cricket. The dendritic Ca2+ transients induced by synaptically‐evoked action potentials had larger amplitudes than those induced by backpropagating spikes evoked by antidromic stimulation. The amplitude of the [Ca2+]i changes induced by antidromic stimuli combined with subthreshold synaptic stimulation was not different from that of the Ca2+ increases evoked by the backpropagating spikes alone. This result means that the synaptically activated Ca2+ release from intracellular stores does not contribute to enhancement of Ca2+ elevation induced by backpropagating spikes. On the other hand, the synaptically evoked action potentials were also increased at distal dendrites in which the Ca2+ elevation was enhanced. When the dendritic and axonal spikes were simultaneously recorded, the delay between dendritic spike and ascending axonal spike depended upon which side of the cercal nerves was stimulated. Further, dual intracellular recording at different dendritic branches illustrated that the dendritic spike at the branch arborizing on the stimulated side preceded the spike recorded at the other side of the dendrite. These results suggest that the spike‐initiation site shifts depending on the location of the activated postsynaptic site. It is proposed that the difference of spike propagation manner could change the action potential waveform at the distal dendrite, and could produce synaptic activity‐dependent Ca2+ dynamics in the giant interneurons. © 2002 Wiley Periodicals, Inc. J Neurobiol 53: 44–56, 2002
Robust parameter‐free algebraic multilevel preconditioning
Authors: Notay Y.
Published: October 2002

To precondition large sparse linear systems resulting from the discretization of second‐order elliptic partial differential equations, many recent works focus on the so‐called algebraic multilevel methods. These are based on a block incomplete factorization process applied to the system matrix partitioned in hierarchical form. They have been shown to be both robust and efficient in several circumstances, leading to iterative solution schemes of optimal order of computational complexity. Now, despite the procedure is essentially algebraic, previous works focus generally on a specific context and consider schemes that use classical grid hierarchies with characteristic mesh sizes h,2h,4h, etc. Therefore, these methods require some extra information besides the matrix of the linear system and lack of robustness in some situations where semi‐coarsening would be desirable. In this paper, we develop a general method that can be applied in a black box fashion to a wide class of problems, ranging from 2D model Poisson problems to 3D singularly perturbed convection–diffusion equations. It is based on an automatic coarsening process similar to the one used in the AMG method, and on coarse grid matrices computed according to a simple and cheap aggregation principle. Numerical experiments illustrate the efficiency and the robustness of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd.
A box scheme for transcritical flow
Authors: Johnson T. C. , Baines M. J. , Sweby P. K.
Published: October 2002

The accurate computer simulation of river and pipe flow is of great importance in the design of urban drainage networks. The use of implicit numerical schemes allows the time step to be chosen on the basis of accuracy rather than stability, offering a potential computational saving over explicit methods.

The highly successful Box Scheme is an implicit method which can be used to model a wide range of subcritical and supercritical flows. However, care must be taken over the modelling of transcritical flows since, unless the correct internal boundary conditions are imposed, the scheme becomes unstable. The necessity of accurately tracking all the critical interfaces and treating them accordingly can be algorithmically complex and in practice the underlying mathematical model is often modified to ensure that the flow remains essentially subcritical. Such a modification however inevitably leads to additional errors and incorrect qualitative behaviour can be observed.

In this paper we show how the technique of ‘residual distribution’ can be successfully implemented in order to accurately model unsteady transcritical flow without the need to know a priori which regions of the computational domain correspond to subcritical and supercritical flow. When used in conjunction with a form of artificial smoothing, the resulting method generates very high resolution results even for transcritical problems involving shocks, as can be seen in the numerical results. Copyright © 2002 John Wiley & Sons, Ltd.
Compensatory bone remodelling in moose: a study of age, sex, and cross‐sectional cortical bone dimensions in moose at Isle Royale National Park
Authors: Hindelang Mary , Peterson Rolf O. , Maclean Ann L.
Published: October 2002

We studied interrelationships among age, sex, and cross‐sectional cortical bone dimensions using quantitative computed tomography (QCT) scans of metatarsal bones of 180 moose (Alces alces) that died in Isle Royale National Park, Michigan. As a large‐bodied quadruped with demanding ecological constraints on movement and behaviour, a moose experiences different weight‐bearing and mechanical stressors than humans, to whom most existing studies of mechanical adaptations of bone pertain. In moose, both sexes showed significant subperiosteal expansion and an increase in medullary area, with an overall increase in cortical bone area over time. Female moose did not exhibit cortical thinning or reduction in cross‐sectional area with age, rather they showed an increase in cortical bone area with periosteal apposition exceeding endosteal resorption, similar to the males. We also found that moose undergo changes in bone geometry through remodelling of bone similar to humans, suggesting a compensatory mechanism for increasing bone strength under conditions of decline in bone mineral density with age. Copyright © 2002 John Wiley & Sons, Ltd.
Editorial note: Introduction to research articles
Authors: Reuter Peter
Published: October 2002

JPAM aspires to cover a wide range of policy topics and variety of methods. This issue shows the usual range
of coverage: welfare reform, public management, methodology, and environmental decisionmaking. Articles on
unfamiliar topics or using unfamiliar methods sometimes challenge readers. Meanwhile, abstracts aim to summarize
the article for specialist readers rather than for a broader audience. One remedy for this problem, the
Editorial Board suggested, is a more accessible and less technical introductory essay that gives the reader a
better sense of what makes each article worth reading; the Brookings Papers on Macroeconomic Activities provides
a long‐established model of this kind of introduction. Surely no one will read every article, but this
endeavor may lead some readers to peruse articles they would otherwise have skipped. The next four issues will
serve as an experimental period, at the end of which I will seek feedback as to whether the essays are helpful.
The summaries of the articles are initially prepared by the authors and then edited for integration into this
essay. © 2002 by the Association for Public Policy Analysis and Management.
Heterogeneous expression of cell adhesion molecules by endothelial cells in ARDS
Authors: Müller Annette M. , Cronen Claus , Müller Klaus‐Michael , Kirkpatrick C. James
Published: October 2002

ARDS (acute respiratory distress syndrome) can be associated with septic shock and multiple organ failure caused by an uncontrolled systemic inflammatory response to Gram‐negative bacterial infection. While in animal models the key role of the endothelial adhesion molecules ICAM‐1, E‐selectin, and VCAM in ARDS has been extensively studied, there are scarcely any corresponding pathomorphological studies of human lung tissue. Hence, little is known about whether there is a comparable, or even heterogeneous, expression pattern of these molecules in the human pulmonary vasculature. This study was therefore undertaken to investigate the immunohistochemical expression of the constitutively expressed PECAM (CD31) and the inducible molecules ICAM‐1, E‐selectin, and VCAM in ARDS lungs from patients who had died in septic shock induced by Gram‐negative bacteria. While in all specimens (ARDS and normal lungs) there was homogeneous strong expression of PECAM in all vessels, ICAM‐1 was clearly up‐regulated in ARDS lungs. E‐selectin and VCAM were not expressed by endothelial cells (ECs) in normal lungs, but in ARDS lungs there was strong expression of both molecules in larger vessels, while in the capillaries there was only mosaic‐like weak expression of a few ECs. This immunohistochemical investigation demonstrates the induction and up‐regulation of adhesion molecules in human ARDS lungs, comparable to that described in animal models. There is also markedly heterogeneous expression of E‐selectin and VCAM, indicating toporegional differences in the function of pulmonary ECs. Copyright © 2002 John Wiley & Sons, Ltd.
Polymerization of methyl methacrylate by 2‐pyrrolidinone and n‐dodecyl mercaptan
Authors: Hu Yu‐Hsiang , Chen Chuh‐Yung
Published: October 2002

The bulk polymerization of methyl methacrylate initiated with 2‐pyrrolidinone and n‐dodecyl mercaptan (R‐SH) has been explored. This polymerization system showed “living” characteristics; for example, the molecular weight of the resulting polymers increased with reaction time by gel permeation chromatographic analysis. Also, the polymer was characterized by Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR techniques. The polymer end with the iniferter structures was found. By the initial‐rate method, the polymerization rate depended on [2‐pyrrolidinone]1.0 and [R‐SH]0. Combining the structure analysis and the polymerization‐rate expression, a possible mechanism was proposed. n‐Dodecyl mercaptan served dual roles—as a catalyst at low conversion and as a chain‐transfer agent at high conversion. Finally, the thermal properties were studied, and the glass‐transition temperature and thermal‐degradation temperature were, respectively, 25 and 80–100 °C higher than that of the azobisisobutyronitrile system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3692–3702, 2002
Properties of amphoteric polyurethane waterborne dispersions. III. Isoelectric points and precipitation
Authors: Dong Anjie , Hou Guoling , Feng Menghuang , Li Aigui
Published: October 2002

The isoelectric points of amphoteric polyurethane (APU) with hydrophobic soft segments and pendent COOH and CH2N(CH3)2 groups and the effect of inorganic salts on the isoelectric points were investigated by the conductivity titration method. The pH values at isoelectric points agreed with the theoretical isoelectric point equations of Patrickios and Merle with pKa = 6.1 and pKb = 8.3, even though, as an ionomer, APU has a low density of ionizable groups on the macromolecular chains and takes a micellar state in aqueous media. The precipitation of APU waterborne dispersions also was observed around the isoelectric points and around lower or higher pH values with the ultraviolet spectrophotometric method. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2440–2448, 2002
Modification of porous poly(ether sulfone) membranes by low‐temperature CO2‐plasma treatment
Authors: Wavhal Dattatray S. , Fisher Ellen R.
Published: October 2002

A general method of modifying the entire cross section of porous poly(ether sulfone) membranes with a low‐temperature CO2‐plasma treatment is reported. Both surfaces of the membranes are highly hydrophilic, with a water drop on the surface disappearing in less than 1 s, even 6 months after plasma treatment. This high hydrophilicity of both membrane surfaces results from the incorporation of hydrophilic functionalities, as evidenced by Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The incorporation of these hydrophilic functionalities takes place primarily during plasma treatment, with some incorporation of atmospheric oxygen and nitrogen immediately upon exposure to air. Scanning electron microscopy shows that the membrane surface is covered by a thin, white layer that is likely the result of etching and redeposition of sputtered surface fragments. An increase in the water bubble point and glass‐transition temperature is also observed for CO2‐plasma‐treated membranes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2473–2488, 2002
Experimental characterization of the volume strain of poly(vinylidene fluoride) in the region of homogeneous plastic deformation
Authors: Quatravaux T. , Elkoun S. , G'Sell C. , Cangemi L. , Meimon Y.
Published: October 2002

Damage to poly(vinylidene fluoride) was studied under uniaxial tension testing at different temperatures and strain rates. A satisfactory accuracy was reached with an original procedure for the assessment of the principal strains and volume strain. The semicrystalline polymer exhibited an increase in the volume strain with the true axial strain caused by material damage. This damage depended on the temperature and strain rate and was related to the whitening phenomenon generally observed. The use of the general ideas of Bucknall's model, based on the decomposition of the whole volume strain into three components, allowed the extraction of the component of the volume strain corresponding to microstructural mechanisms of plastic deformation other than shearing. Therefore, nucleation and growth stages of cavitation were revealed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2516–2522, 2002
Observations on granite weathering phenomena, Mount Keinath, Northern Victoria Land, Antarctica
Authors: French H. M. , Guglielmin M.
Published: October 2002

Rock varnish, erosional grooves, and well‐developed cavernous weathering phenomena occur in close association on a small biotite‐monzogranite nunatak in the Northern Foothills region, Northern Victoria Land, Antarctica. The grooves, similar in appearance to the ‘rinnenkarren’ described in the karst literature, are developed on steeply inclined (>35°) bedrock surfaces while the rock varnish occurs on adjacent, more gently sloping (<15°) bedrock surfaces. The varnish forms a resistant carapace through which small weathering pits have developed and below which are large cavernously weathered hollows (taffoni). We argue that the intimate association between the grooves and the rock varnish indicate the nunatak has been exposed to a long period of subaerial weathering. The preservation of both phenomena supports (a) the idea that landscape modification in this exceptionally cold and arid region of Antarctica is very slow and (b) the long‐term stability of the Antarctic ice sheet. Copyright © 2002 John Wiley & Sons, Ltd.
The fluvial morphodynamics of two small permafrost drainage basins, Richardson Mountains, Northwestern Canada
Authors: Priesnitz Kuno , Schunke Ekkehard
Published: October 2002

Based on hydrological fieldwork in the tundra of northwestern Canada during the springs of 1986, 1990, 1992, and 1994 and the summers of 1998, 1999, and 2000 the paper deals with the fluvial processes induced by spring snowmelt and by summer rainfall in two small stream valleys. At the end of winter the floors of these flat‐bottomed valleys are covered by icings (aufeis) over most of their length. The biggest quantity of meltwater runoff passes in an ice channel on top of the icing, with flow velocities up to 4.8 m/s. The main solid‐sediment transport takes place through the short runoff interval, when the stream channel has entrenched the aufeis in some places. The calculated suspended load transport during snowmelt flood varied from 62–313 t/km2 in different years. In summer, suspended‐sediment transport varies between 0.2–1.4 t/km2. There are no data about the frequency of exceptionally strong precipitation events, similar to those that occurred during the 1999 summer in the Douglas Creek basin that led to a suspended load transport of 153 t/km2 and a bedload transport of 444 t/km2 in about 12 days. The average annual suspended‐sediment yield for Andy Creek is 71 t/km2/yr, and 328 t/km2/yr for Douglas Creek. The average annual solutes yield for Andy Creek is 19 t/km2/yr, and 52 t/km2/yr for Douglas Creek. If one includes the hardly‐recordable bedload transport, the total equivalent surface lowering rate by fluvial solids transport is about 350 mm/1000yr for the Andy Creek basin and 850 mm/1000yr for the Douglas Creek basin. Copyright © 2002 John Wiley & Sons, Ltd.
Inhalation and deposition of nebulized sodium cromoglycate in two different particle size distributions in children with asthma
Authors: Nerbrink O.L. , Lindström M. , Meurling L. , Svartengren M.
Published: October 2002

The relative deposition of two inhaled droplet size distributions of sodium cromoglycate produced by a Hudson Updraft II nebulizer was evaluated, using a setup modified from the proposed Comité Européen Normalisé (CEN) standard prEN 13544‐1. The modified setup comprised an Andersen 296 impactor and a Spira Electro 2 dosimeter. The setup was characterized prior to use in children with sodium cromoglycate (SCG) and sodium fluoride as tracer aerosol. The main in vivo study was designed to allow nine children with a mean age of 10 years to inhale SCG aerosol at two different relative humidities (RH), a high RH (> 90%) and a low RH (13%), which in turn resulted in two different droplet size distributions. The nebulizer/dosimeter was set to provide 1‐sec nebulization during 50 inhalations. Throughout the exposures, the children were instructed to inhale in a consistent manner with target tidal volumes (0.5 L) and inhalation flows (0.4 L/sec). Blood samples were taken at predefined time intervals, and the area under the curve (AUC) was calculated. A lung deposition program, TGLD2, was used to calculate the expected deposition, using the droplet sizes and inhalation parameters obtained during in vivo exposures.

The in vivo monitoring of droplet size distribution during the exposure showed that the low, intermediate (room air), and high RHs gave a mean droplet size distribution with a mass median aerosol diameter (MMAD) of 1.2, 1.7, and 2.0 μm, respectively. The average tidal volume over all exposures was 0.51 ± 0.12 L. The total deposition fraction was 33.4% of the estimated nebulizer output. A correlation was found between tidal volume and the calculated deposited fraction.

The results indicate that there is a difference in total deposition, depending on the size of the droplet size distribution, with the larger droplet size distribution (MMAD, 2.0 μm) having a higher total deposition than the smaller droplet size distribution (MMAD, 1.2 μm). The deposition results were in good agreement with the deposition fractions estimated using the TGLD2 software for the inhalation parameters found in the study. The obtained study results can arise from differences in regional deposition, but may also be explained by differences in extrathoracic deposition. Pediatr Pulmonol. 2002; 34:351–360. © 2002 Wiley‐Liss, Inc.
Horseshoe lung with pseudo‐ring‐sling complex
Authors: Hwang Haw‐Kwei , Chen Ming‐Ren , Chen Shyh‐Jye , Kao Hsin‐An , Lee Kuo‐Sheng , Shih Shin‐Lin
Published: October 2002

We report on a 1‐month‐old boy who presented with a “horseshoe” lung, complete “O” rings of the trachea, and an unusual course of the left pulmonary artery mimicking a left pulmonary artery sling. Computed tomography, cardiac catheterization, and bronchoscopy were performed to confirm the rare coexistence of these anomalies. To our knowledge, such a combination of anomalies has not been reported in the English‐language literature. Pediatr Pulmonol. 2002; 34:402–404. © 2002 Wiley‐Liss, Inc.
Abernethy malformation: One of the etiologies of hepatopulmonary syndrome
Authors: Alvarez Alfonso E. , Ribeiro Antônio F. , Hessel Gabriel , Baracat Jamal , Ribeiro José D.
Published: October 2002

Hepatopulmonary syndrome (HPS) is the clinical relationship between hepatic disease and the existence of pulmonary vascular dilatations, which can result in a range of arterial oxygenation abnormalities. It is probably caused by an alteration in the synthesis or metabolism of vasoactive pulmonary substances at a hepatic level, leading to vasodilatation of pulmonary vessels and diffusion perfusion defects. The Abernethy malformation is characterized by the congenital diversion of portal blood away from the liver, by either end‐to‐side or side‐to‐side shunt. Here, we report on a 5‐year‐and‐11‐month‐old‐boy who had started cyanosis at age 4 years and 11 months, and did not have any other pulmonary or cardiac signs or symptoms. In the investigation, arterial blood gases revealed a PaO2 of 41.4 mm Hg. The chest x‐ray film and echo Doppler cardiography were normal. Nuclear scanning with Technetium 99m‐labeled macroaggregated albumin showed the presence of arteriovenous shunt, at 47%. Abdominal echography revealed Abernethy malformation with an absence of portal vein. We concluded that the patient had HPS caused by Abernethy malformation. The possible mechanism is that in this malformation, there is a deviation in the blood that comes from the spleen to the vena cava without passing through the liver, so there is no metabolism of some substances which can be responsible for the imbalance between the vasodilatation and the vasoconstriction of the pulmonary circulation. Abernethy malformation must be included as one of the etiologies of hepatopulmonary syndrome. This is the first case described in the literature with this form of presentation. Pediatr Pulmonol. 2002; 34:391–394. © 2002 Wiley‐Liss, Inc.
bcl‐2 antagonizes the combined apoptotic effect of transforming growth factor‐β and dihydrotestosterone in prostate cancer cells
Authors: Bruckheimer Elizabeth M. , Kyprianou Natasha
Published: October 2002

BACKGROUND

We previously demonstrated that dihydrotestosterone (DHT) enhances transforming growth factor‐β (TGF‐β) ‐induced apoptosis in human prostate cancer cells (Endocrinology 2001;142:2419–2426).

METHODS

In this study, the ability of the apoptosis suppressor bcl‐2 to directly antagonize the combined apoptotic effect of TGF‐β and DHT in the androgen‐sensitive LNCaP TβRII prostate cancer cells was examined. The previously cloned TGF‐RβII receptor LNCaP cells, responsive to both TGF‐β and androgens, were engineered to overexpress the bcl‐2 oncoprotein and the profile of apoptosis induction was analyzed in response to TGF‐β alone (5.0 ng/ml) or in combination with DHT (1 nM).

RESULTS

Biological characterization of cloned LNCaP TβRII hygromycin/bcl‐2 transfectants demonstrated that bcl‐2 overexpression resulted in a significant inhibition of the combined TGF‐β and DHT apoptotic effect in prostate cancer cells (P < 0.01). Furthermore, molecular analysis indicated that this antagonistic effect of bcl‐2 on apoptosis was due to partial suppression of TGF‐β and DHT‐mediated induction of caspase‐1 expression and activation in LNCaP TβRII‐hygro/bcl‐2 transfectants. These results support a potential bcl‐2 interference with the TGF‐β and androgen apoptotic signaling in prostate cancer cells by means of an antagonistic effect on caspase‐1 activation.

CONCLUSION

This evidence may have mechanistic significance in understanding the contribution of bcl‐2 overexpression in the development of androgen‐independent prostate cancer by means of conferring resistance to TGF‐β–mediated apoptosis. Prostate 53: 133–142, 2002. © 2002 Wiley‐Liss, Inc.
Target sites for herbicides: entering the 21st century
Authors: Wakabayashi Ko , Böger Peter
Published: October 2002

At present the use‐rate of modern herbicides is in the range of 100–300 g AI ha−1, with a tendency to decline. The low use‐rate (ca 10 g AI ha−1) of the original sulfonylurea and cyclic imide herbicides prompted agrochemical scientists to look for even more active compounds which led to the successive discoveries of many new herbicidal acetolactate synthase inhibitors and no less than 18 cyclic imides in the class of protoporphyrinogen‐IX oxidase inhibitors in the 1990s. In this paper, mechanisms of action related to function and biosynthesis of chlorophylls, carotenoids, plastoquinone, amino acids, fatty acids and photosynthetic electron transport and other metabolic processes are discussed as plant‐specific herbicidal target domains.

© 2002 Society of Chemical Industry
Introduction
Authors: Ishaaya Isaac , Ishaaya Isaac
Published: October 2002

© 2002 Society of Chemical Industry
Simple assay for antitumour immunoactive glycoprotein derived from Chlorella vulgaris strain CK22 using ELISA
Authors: Noda Kiyoshi , Tanaka Kuniaki , Yamada Akira , Ogata Jyunko , Tanaka Hiroyuki , Shoyama Yukihiro
Published: October 2002

A quantitative ELISA system was developed using a monoclonal antibody (MAb) specific for an antitumour immunoactive glycoprotein (CVS) derived from C. vulgaris strain CK22. The full measuring range of the assay extends from 0.63 to 10.0 ng/mL of CVS. Although no cross‐reaction was observed to proteins tested or other biological response modifiers (BRMs) derived from different sources, cross‐reactions were found with culture supernatants from two other strains of C. vulgaris having a strong antitumour immunoactivity. Treatment of CVS with protease, acid or alkali weakened or completely eliminated the reactivity against the MAb and also its antitumour immunoactivities. This ELISA system is suitable for the biologically active form of CVS derived from C. vulgaris strain CK22 and related immunoactive strains. Copyright © 2002 John Wiley & Sons, Ltd.
Bosons and fermions in a one‐dimensional harmonic oscillator potential
Authors: Wybourne Brian G.
Published: October 2002

The symmetry properties of bosons and fermions in a one‐dimensional harmonic oscillator are explored. It is shown that there is a one‐to‐one correspondence between the counts of the maximal spin states states formed by N‐noninteracting bosons and fermions in a one‐dimensional harmonic oscillator. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
The origin of spontaneous point mutations in DNA via Löwdin mechanism of proton tunneling in DNA base pairs: Cure with covalent base pairing*
Authors: Kryachko Eugene S.
Published: October 2002

The key aim of the present work is twofold. On the one hand, we propose a novel model of the tautomerization of the A⋅T base pair leading to its mismatches and supporting thus the Löwdin mechanism of the proton transfers taking place within the valley formed by its mispairs. Its specific novelty is actually in that the existing barrier of ca. 23 kcal/mol is not directly related to the proton transfer. Rather, it governs a shift of the bases within the Watson–Crick A⋅T base pair relative to each other and separates it from the valley in its potential energy surface where the mispairing occurs quite easily due to lower barriers of the proton transfers therein. On the other hand, aiming to cure the DNA double helix of generating hydrogen‐bonded mispairs, which lead to the spontaneous point mutations in the genetic alphabet, by inserting covalent base pairs into the DNA architecture, we subject the covalent bond base pair designed recently by Gao and Orgel (Proc Natl Acad Sci USA 1999, 96, 14837) to the high‐level performance computational study. Its three tautomeric forms are found and it is shown that the most stable one is characterized by the amide‐type hydrogen bond. The comparison of the properties such as rotational constants, dipole moment, polarizability, and quadrupole moment is carried out for the Gao–Orgel covalent base pair and the canonical A⋅T one. We demonstrate that the former one can be easily inserted into the double helix DNA without any significant perturbations of the double helix architecture. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Growth pattern and bonding of copper clusters
Authors: Jug Karl , Zimmermann Bernd , Köster Andreas M.
Published: October 2002

Density functional theory calculations of copper cluster Cunwithn=2–10 are analyzed with respect to their molecular orbitals. It is shown that shell type orbitals ofs,p, anddcharacter govern the electronic structure growth and have an influence on the geometric structure. They appear as highest occupied molecular orbital, lowest unoccupied molecular orbital, or as orbitals energetically close to these. Their occurrence can explain the magic numbers of shell models. The bonding in such structures can be explained by an analysis of the critical points of the molecular electrostatic potential. Six types of critical points are observed and related to bonds, rings, cages, lone pairs, and their connections. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
On Löwdin's method of symmetric orthogonalization*
Authors: Mayer I.
Published: October 2002

An elementary direct proof is given for the stationarity property of Löwdin's symmetric orthogonalization scheme. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002