bluuebunny/crossref_metadata_2025 huggingface dataset:
TLM‐based solutions of the Klein–Gordon equation (Part II)
Authors: O'Connor William J. , Clune Fergus J.
Published: October 2002

In Part I, two TLM‐based solutions were presented for the Klein–Gordon Equation in its basic form, with the TLM pulses representing the primary variable. In Part II, two further approaches are presented in which the TLM pulses now represent derivatives of the primary variable, with respect to either space or time. As in Part I, the two solution schemes were verified symbolically and numerically. They illustrate further ways to extend the power of TLM beyond its traditional application areas. Some of these areas are discussed briefly. Copyright © 2002 John Wiley & Sons, Ltd.
Who's helping whom? Layers of culture and workplace behavior
Authors: Perlow Leslie , Weeks John
Published: October 2002

This paper describes an in‐depth, qualitative exploration of helping behavior among software engineers doing the same type of work in the U.S. and India. Consistent with research describing American culture as more individualist and Indian culture as more collectivist, we find that engineers at the American site provide help only to those from whom they expect to need help in the future, whereas engineers at the Indian site are more willing to help whoever needs help. However, we further find that the differences are not due to the influence of individualistic or collectivist norms per se but rather to the ways in which helping is framed in the two contexts. At the American site, the act of helping is framed as an unwanted interruption. In contrast, helping at the Indian site is framed as a desirable opportunity for skill development. These different framings reflect the combined influence of national, occupational, and organizational layers of culture in the two settings. In each case, we find that engineers help others when doing so is framed in such a way as to be perceived as helpful in achieving their career goals. Our findings have important implications for better understanding helping behavior itself and also the mechanisms through which culture influences work behavior. Copyright © 2002 John Wiley & Sons, Ltd.
The process of burnout in white‐collar and blue‐collar jobs: eight‐year prospective study of exhaustion
Authors: Toppinen‐Tanner Salla , Kalimo Raija , Mutanen Pertti
Published: October 2002

This study tested three contrasting theories about the sequential process of the three dimensions of burnout (i.e., exhaustion, cynicism and professional efficacy) as measured by the Maslach Burnout Inventory—General Survey (MBI‐GS). The causal order of the burnout components was investigated by including job stressors as antecedents of burnout in structural equation models (LISREL). The predictive effect of exhaustion on burnout dimensions eight years later was also investigated. The longitudinal models were then tested in two occupational subgroups. The participants were 713 Finnish employees (415 white‐collar and 298 blue‐collar workers) from an international industry enterprise. The best fitting model of the associations between the three burnout dimensions was obtained by a path model where exhaustion predicted cynicism, and cynicism in turn predicted lack of professional efficacy. The symptoms of exhaustion were persistent over time. There were no differences between the two occupational groups in the process of burnout. Also the work‐related antecedents of burnout (job stressors) were very similar in both groups. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopy of the phase‐related basic copper arsenate minerals olivenite, cornwallite, cornubite and clinoclase
Authors: Frost Ray L. , Martens Wayde N. , Williams Peter A.
Published: October 2002

The Raman spectra of olivenite, cornwallite and its diamorph cornubite and clinoclase were obtained at 298 and 77 K using a combination of a thermal stage and Raman microscopy. The vibrational spectra of the minerals are different, in line with differences in crystal structure and composition. Some similarity in the Raman spectra of the hydroxyl‐stretching region exists, particularly at 298 K. Two hydroxyl‐stretching wavenumbers are observed for each mineral with the bands for clinoclase being well separated. Characteristic differences in the OH deformation regions are observed. Differences are also observed in the arsenate stretching and deformation regions. The OAsO bending modes are identified. The application of Raman microscopy to the study of closely related mineral phases allowed their molecular characterization using their Raman spectrum, thus permitting the rapid identification of phases in complex mixtures of secondary copper arsenates from the oxidized zones of base metal ore bodies. Copyright © 2002 John Wiley & Sons, Ltd.
Leadership boards of directors
Authors: Davies Adrian , Joyce Paul , Beaver Graham , Woods Adrian
Published: October 2002

Boards of directors that have a leadership role in corporate strategic planning go beyond merely caring for shareholder interests and take a proactive role in the success of the business. They do this by setting the strategic direction and evaluating company performance.

The cultural and organizational conditions for the development of leadership boards are however, not well understood. The roles of executive and non‐executive directors need to be clearly defined in order that such boards can be effective and assert control over strategy and performance. Executive directors can only be effective when they clearly differentiate their role of providing direction from their daily role of working with managers in the company.

Recent research has begun to push back the ignorance surrounding the development of leadership boards. This will be examined in order to define the barriers standing in the way of more empowered directors. It will then be used to identify the actions and approaches that can be used by directors to develop their involvement in, and influence over, corporate strategic planning.

This is then followed by a discussion of boards that places the issue in their contemporary policy context. It leads to the conclusion that the organization of partnership between board and management is important and that business success increasingly rests on openness and trust supported by creative and challenging dialogue.

Copyright © 2002 John Wiley & Sons, Ltd.
Determination of the lipid content in fish muscle by a self‐calibrated NMR relaxometry method: comparison with classical chemical extraction methods
Authors: Toussaint Caroline A , Médale Françoise , Davenel Armel , Fauconneau Benoît , Haffray Pierrick , Akoka Serge
Published: October 2002

A low‐cost, accurate NMR method was developed to determine the lipid content in fish flesh. The fish samples are dried before NMR measurements, and the method is self‐calibrated with an oil reference. The NMR technique gave an intermediate fat content value, 4.7% lower in relative value than those obtained by a chemical cold extraction method and 6.7% higher than those from a petroleum ether extraction method at high temperature. Taking into account this systematic bias, the prediction error was only 3 g kg−1 fat content between NMR and Soxhlet method determinations (R2 = 0.98). The NMR technique thus offers a promising alternative method for determining the lipid content in previously dried fish flesh, since it is rapid, easily usable and solvent‐free, unlike chemical extraction methods. Furthermore, this accurate NMR method should be valuable to calibrate the fast but less accurate NMR, NIR and microwave methods based on fresh samples and to estimate the fat content in other animal meats when the fat is maintained in an amorphous state.

© 2001 Society of Chemical Industry
Nutritional evaluation of transgenic high‐methionine lupins (Lupinus angustifolius L) with broiler chickens
Authors: Ravindran Velmurugu , Tabe Linda M , Molvig L , Higgins T J V , Bryden Wayne L
Published: October 2002

The nutritive value of transgenic lupin seeds (Lupinus angustifolius L) with higher contents of methionine was evaluated with broiler chickens. The crude protein, methionine and cysteine contents in the conventional and transgenic lupins were 322 and 324, 2.0 and 4.5, and 3.6 and 3.7 g kg−1 dry matter respectively. In the feeding trial, conventional and transgenic lupins with hulls were incorporated into a maize–soyabean meal diet at 250 g kg−1 level and the diets were fed to female broiler chicks from 6 to 20 days of age. All diets were balanced to contain similar levels of apparent metabolisable energy (AME), lysine and sulphur‐containing amino acids. The levels of free methionine added to the maize–soyabean meal control, conventional lupin and transgenic lupin diets were 2.2, 2.8 and 2.2 g kg−1 respectively. Weight gain and feed intake were not influenced by dietary treatments, but feed/gain tended to be higher (P  = 0.09) in birds fed lupin diets compared with those fed the control diet. Feed/gain of birds fed the conventional lupin diet was higher (1.82 vs 1.74) than for those fed the transgenic lupin diet. These results showed that the supplemental methionine required in poultry diets containing 250 g kg−1 lupin can be lowered by 0.6 g kg−1 diet by the use of high‐methionine lupins. The AME values of conventional and transgenic lupins were determined to be 9.42 and 10.18 MJ kg−1 dry matter respectively. The higher AME value in transgenic lupins may be related to the lower content of soluble non‐starch polysaccharides (45.6 vs 60.7 g kg−1 air‐dry basis). Data on ileal amino acid digestibility indicate that the amino acids in transgenic lupins are as digestible as those in conventional lupins.

© 2002 Society of Chemical Industry
Transfer of heat and moisture during microwave baking of potatoes
Authors: Wilson W D , MacKinnon I M , Jarvis M C
Published: October 2002

Microwave baking of potatoes comprised two phases. In the first phase the internal temperature of the potatoes rose to approximately 100 °C with little loss of water vapour. The uniformity of internal heating during this phase was assessed by identifying gelatinised starch. Starch gelatinisation began near the outer surface after 1.5 min of cooking and was complete by 2.5 min. During the second cooking phase the thermal energy absorbed was used to evaporate water. When immersion in boiling water was substituted for this second phase of microwave cooking, it took significantly longer for the internal texture to soften adequately for the potatoes to be considered cooked. This suggests that microwave cooking influences texture independently of the thermal profile of the cooking process. Damage by escaping steam is suggested as a mechanism.

© 2002 Society of Chemical Industry
Establishment and characterization of OCUT‐1, an undifferentiated thyroid cancer cell line expressing high level of telomerase
Authors: Ogisawa Kana , Onoda Naoyoshi , Ishikawa Tetsuro , Takenaka Chiemi , Inaba Masaaki , Ogawa Yoshinari , Chung Kosei Hirakawa‐YS
Published: October 2002

Background & Objectives

Undifferentiated thyroid cancer is one of the most aggressive human malignancies, and the prognoses that have been reported are extremely poor. A number of studies have described the clinicopathologic features of this tumor and analyzed its biologic background to explain the extraordinarily aggressive nature of the tumor. Still the mechanism of cellular aggressiveness in undifferentiated thyroid cancer is not yet fully understood.

Methods

We established and characterized an undifferentiated thyroid cancer cell line, OCUT‐1, derived from the surgical specimen obtained from a 74‐year‐old Japanese woman with advanced undifferentiated thyroid cancer.

Results

The cell line had already maintained over 100 passages and was stably cultured for more than a year. The cell line was observed to maintain not only its morphologic similarity to the primary cancer cells, but also its aggressive nature, including high proliferative activity, numerous genetic abnormalities, and cytokine production. Further, we have demonstrated the expression of telomerase activity in the cell, which could represent one of the responsible mechanisms for the cellular aggressiveness of this type of tumor.

Conclusions

This cell line might be useful for further study concerning the correlation between telomerase activation and disease progression or anaplastic change in thyroid cancer. J. Surg. Oncol. 2002;80:197–203. © 2002 Wiley–Liss, Inc.
Effects of dietary chromium picolinate supplementation on serum and tissue mineral contents of laying Japanese quails
Authors: Şahin Kazim , Şahin Nurhan , Küçük Osman
Published: October 2002

This experiment was conducted to evaluate the effects of chromium (chromium picolinate, CrPic) on serum and tissue concentrations of Cr, Zn, Cu, Fe, and Mg of laying Japanese quails (Coturnix coturnix japonica). One hundred fifty laying Japanese quails (45 days old) were divided into five groups, 30 quails per group. The laying quails were fed either the control diet containing 1,285.96 μg of Cr/kg of diet or the control diet supplemented with 200, 400, 800, or 1,200 μg of Cr/kg of diet. Increasing dietary chromium supplementation linearly increased serum chromium and zinc concentrations (P = 0.01) but linearly decreased (P = 0.01) copper serum concentrations. Serum iron and magnesium concentrations did not change (P > 0.10) as dietary chromium supplementation increased. Similar response to Cr supplementation was also observed in tissue mineral concentrations. Liver, longissimus muscle, and kidney chromium and zinc concentrations linearly increased (P = 0.01), whereas copper concentrations linearly decreased (P = 0.01) as dietary chromium supplementation increased. Also, liver, longissimus muscle, and kidney iron and magnesium concentrations did not change (P > 0.10) as dietary chromium supplementation increased. The results of present study conclude that supplemental chromium to the diet of Japanese quails influences serum and tissue Cr, Zn, and Cu concentrations, thus most probably functions of the organs as well as the welfare of Japanese quails. J. Trace Elem. Exp. Med. 15:163–169, 2002. © 2002 Wiley‐Liss, Inc.
Spatial and temporal changes of vegetation cover in granite mountains in central Japan: a GIS‐based approach
Authors: Kimoto A. , Mizuyama T. , Okano K.
Published: October 2002

Degraded hillslope areas are widespread in the Tanakami area located in Shiga Prefecture of central Japan as a result of more than 1300 years of human impact. Consequently, accelerated erosion rates and high storm runoffs have been major environmental problems there. To attempt to stabilize hillslopes and to reduce sediment and water discharges, extensive reforestation projects have been conducted since the 1870s. The vegetation recovery in the Tanakami area over a 51‐year period was assessed using a geographic information system‐based approach. The results showed that, in the areas where only hillside planting work was conducted, the percentage of bare slope area increased mainly due to the destruction of the vegetation cover on the forested slopes with gradients exceeding 30 degrees, and/or on southwest and northwest slopes. Moreover, the destruction of vegetation cover on steep slopes was seen to be most prevalent where hillside planting work was conducted without slope terracing. In contrast, in the area where both hillside planting and tending works were implemented, the bare slope area tended to decrease through the study period. Consequently, in 1988, there were only 1 per cent of bare slopes in the area where both hillside planting and tending works were implemented; in contrast the bare slope areas where only hillside planting work was conducted still occupied 12–17 per cent. These results imply that the reforestation practices that include hillside planting and tending works, or at least slope terracing, are necessary to prevent the destruction of the vegetation cover on steep southwest and northwest slopes. Copyright © 2002 John Wiley & Sons, Ltd.
Scar sarcoidosis—treatment with the Q‐switched ruby laser
Authors: Grema Hortensia , Greve Bärbel , Raulin Christian
Published: October 2002

Background and Objective

Scar sarcoidosis is a circumscribed form of cutaneous sarcoidosis, which is often very difficult to treat. To date, therapeutic approaches have yielded little success and often been accompanied by adverse effects, some of which are severe. Laser treatment is one alternative, which has proven to be effective in a dramatically increasing number of cases over the past years.

Study Design/Patients and Methods

We report about a 50‐year‐old female patient who presented with histologically confirmed scar sarcoidosis on the right elbow and both knees; the sarcoidosis had spontaneously developed on three sites which had traumatic tattoos from abrasions. Because of the reddish‐brown livid discolorations, we treated the granulomas with the pulsed dye laser for three sessions, although without success. Treatment with the Q‐switched ruby laser was commenced to remove the traumatic tattoos.

Results

Not only had the areas lightened fully after four sessions, the sarcoidosis foci had resolved completely, and the patient has been recurrence‐free for over 3 years.

Conclusion

The Q‐switched ruby laser appears to be a rapid and effective means of treating scar sarcoidosis with traumatic tattoos without incurring adverse effects. The definitive mode of action is still not fully known, however. Lasers Surg. Med. 30:398–400, 2002. © 2002 Wiley‐Liss, Inc.
Morphological analysis of cementum and root dentin after Er:YAG laser irradiation
Authors: Sasaki Katia M. , Aoki Akira , Ichinose Shizuko , Ishikawa Isao
Published: October 2002

Background and Objectives

To investigate the morphology of cementum and root dentin after Er:YAG laser irradiation with and without water coolant, compared to that after CO2 laser irradiation and an untreated surface.

Study Design/Materials and Methods

Ten extracted healthy human teeth were used. Er:YAG and CO2 lasers were applied with energy outputs of 0.4 W, with and without coolant and 0.5 W, without coolant, respectively. Scanning electron microscopy (SEM) analysis was performed at high and ultra‐high magnifications.

Results

The surface of cementum was micro‐irregular with numerous projections while that of dentin appeared scaly after Er:YAG laser irradiation. Unlike after CO2 laser treatment, no major melting or cracking was observed with Er:YAG laser treatment. The use of water spray produced fine micro‐irregularities without attached debris. Ultra‐high magnification revealed similar microparticles‐composed aspects for both cementum and dentin. However, the more porous structure of the surface was observed after Er:YAG laser irradiation without water spray.

Conclusions

Cementum and root dentin presented distinct micro‐roughness after Er:YAG laser irradiation, possibly due to structural differences in the original tissue. However, under ultra‐high magnifications, both cementum and dentin presented similar characteristics of the irradiated surface. In addition, the use of water spray during laser irradiation minimized thermal effects and resulted in a cleaner and less porous surface. Lasers Surg. Med. 31:79–85, 2002. © 2002 Wiley‐Liss, Inc.
1.55‐μm surface‐illuminated monolithically integrated balanced metal semiconductor metal photodetectors and coplanar waveguide
Authors: Safwat Amr M. E. , Kim Junghwan , Johnson William , Walker Bobby , Lee Chi H.
Published: October 2002

Two metal–semiconductor–metal (MSM) photodetectors are integrated monolithically with a coplanar waveguide transmission line to form a 1.55‐μm surface‐illuminated balanced photodetector. Illuminating the device with CW and taking the difference, the relative intensity noise (RIN) is suppressed by 9–10 dB. In balanced detection, a 7‐dB enhancement in the intermodulation term compared to single detector is achieved. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 125–130, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10393
Use of wavelet transform to the method‐of‐moments matrix arising from electromagnetic scattering problems of 2D objects due to oblique plane‐wave incidence
Authors: Yu Jin , Kishk Ahmed A.
Published: October 2002

An efficient method is presented for transforming the matrix of the method of moments obtained by the expansion of the unknown surface currents with pulse basis function and the use of point match testing to a matrix with wavelet basis and testing functions. When the electromagnetic scattering object is a dielectric or object under oblique plane‐wave incidence, more than one equivalent surface current component exists at the object surface. When these currents are connected into one current vector in the method of moments, there must be some discontinuities between the current components. These discontinuities make the direct wavelet transform to the whole MoM matrix inefficient and not equivalent to the use of the wavelet functions in the expansion of the unknown currents and the testing. Therefore, the wavelet transform must be constructed in a different way to avoid these discontinuities. Here, the proper wavelet transform that is equivalent to the use of the wavelet functions in the MoM, which avoids such discontinuities, is presented. This transform is referred to as wavelet subtransform. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 130–134, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10394
Experimental investigation of antenna‐handset‐feed interaction during wireless product testing
Authors: Haley J. , Moore T. , Bernhard J. T.
Published: October 2002

Chassis shape and element design dominate portable antenna circuit and radiation properties. In terms of far‐field pattern and input reflection magnitudes, this work experimentally investigates at 1.9 GHz the interplay between the element, handset size, and feed‐line radiation suppression techniques. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 169–172, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10406
Compact circular‐sided microstrip antenna for circular polarization
Authors: Kundukulam Sona O. , Paulson Manju , Aanandan C. K. , Mohanan P.
Published: October 2002

Development of a new compact circular‐sided microstrip antenna is presented. This antenna offers considerable area reduction compared to standard rectangular microstrip antenna designed for the same frequency. Typical antenna design and experimental results for circular polarization are also demonstrated. The antenna has a 3‐dB axial ratio bandwidth of 1.5%. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 176–177, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10408
Broadband equivalent circuit models for canonical chiral elements
Authors: Long B. R. , Werner D. H.
Published: October 2002

This article introduces broadband equivalent circuit models for both series‐connected and parallel‐connected canonical chiral elements. Each connection method results in a different terminal impedance behavior and therefore requires a different equivalent circuit model. These equivalent circuit models have a variety of applications including allowing for convenient analysis of chiral antennas as well as meta‐materials composed of passively or actively loaded chiral elements. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 181–183, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10410
Analysis of an array of monopoles with the use of a radial waveguide approach
Authors: Janapsatya Januar , Bialkowski Marek E.
Published: October 2002

A radial guide field matching method (RGFMM) is used to analyze a circular array antenna consisting of one active monopole surrounded by a concentric array of passive monopoles terminated in arbitrary loads. An equivalent admittance matrix for this antenna system is determined to study the input admittance of the active monopole when the peripheral elements are terminated in open or short circuits. RGFMM results are compared with free‐space method of moments (FSMoM) results for a small switched‐beam array of seven monopoles. Good agreement is noted. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 235–240, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10426
CAD of coaxially end‐fed waveguide phased‐array antennas
Authors: Galdi Vincenzo , Gerini Giampiero , Guglielmi Marco , Visser Huib J. , D'Agostino Francesco
Published: October 2002

An alternative configuration for an infinite coaxially end‐fed waveguide phased‐array antenna is explored. In the proposed configuration, the integration of the end‐fed launcher and the output waveguide, rather than the waveguide in itself, acts as a basic radiator. This allows the design of more compact antenna elements. In order to analyze and optimize the structure, an accurate full‐wave simulation tool based on the multimode admittance matrix representation is developed. Results are validated against state‐of‐the‐art commercial CAD software. Numerical simulations involving singly and doubly tuned configurations are presented and discussed to illustrate the potential convenience of the proposed configuration and of the CAD tool developed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 276–281, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10437
A compact dual‐port, dual‐band planar microstrip antenna
Authors: Gadzina A. , Słobodzian P.
Published: October 2002

A compact dual‐band, dual‐port planar microstrip antenna is described. Its main properties are wide bandwidth, high and constant gain at both frequency bands, and a simple planar structure, which results from etching all patches onto a common substrate. As an example of application an antenna for GSM900/1800 has been realized and described with measured data. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 302–305, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10443
Parallel FDTD analysis of active integrated antenna array
Authors: Chu Qing‐Xin , Chan Ka‐Fai , Chan Chi‐Hou
Published: October 2002

The active integrated antenna array given in [4] is simulated by use of a parallel FDTD algorithm to reduce the computational requirement. A four‐unit array with dual modes and dual frequencies is presented in this paper. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 317–319, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10447
Treatment of childhood acute lymphoblastic leukemia at a regional non‐academic center in Belarus
Authors: Chunikhovskiy Sergey P. , Zelterman Daniel , van Hoff Jack
Published: October 2002

The outlook for children with cancer is improving in the less privileged nations of the world. This report from Belarus is representative of results that can be achieved. Med Pediatr Oncol 2002;39:202–206. © 2002 Wiley‐Liss, Inc.
The first automated 470.59 MHz 19F NMR‐controlled titration: dissociation constants and ion‐specific chemical shifts of 2‐amino‐4‐fluoro 2‐methylpent‐4‐enoic acid
Authors: Uhlemann C. E. , Pfaff C. G. , Hägele G. , Laue K. W. , Lübke M. , Haufe G.
Published: October 2002

2‐Amino‐4‐fluoro‐2‐methylpent‐4‐enoic acid, obtained as a 1 : 1 salt with trifluoro‐acetic acid, was characterized by 1H and 19F high‐resolution NMR spectroscopy. High‐precision potentiometry led to the dissociation constants pK = 1.879 and pK = 9.054. The first automated 470.59 MHz 19F NMR‐controlled titration yielded the dynamic chemical shift 〈δF〉 as a function of pcH or τ and the ion‐specific chemical shifts: δF(H2L+) = −94.81 ppm, δF(HL) = −94.21 ppm, δF(L−) = −92.45 ppm. The deprotonation gradients were found to be Δ1 = −0.60 ppm and Δ2 = −1.76 ppm. Copyright © 2002 John Wiley & Sons, Ltd.
Conformational analysis of some 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones by 1H NMR spectroscopy and molecular simulation
Authors: Pivnenko Nikolay S. , Drushlyak Tatyana G. , Kutulya Lidiya A. , Vashchenko Valeriy V. , Doroshenko Andrey O. , Goodby John W.
Published: October 2002

Based on 1H NMR spectral analysis combined with molecular simulation, conformational states of the cyclohexanone ring were studied for some 1R,4S‐2‐(4‐X‐benzylidene)‐p‐menthan‐3‐ones (X = COOCH3 or C6H5) in CDCl3 and C6D6. The co‐existence of chair conformers with an axial orientation of both alkyl substituents and twist‐boat forms was established for the compounds studied at room temperature (22–23° C). The substituent X does not influence appreciably the ratio of these conformers, but the fraction of twist‐boat forms increases noticeably in benzene solutions as compared with CDCl3 solutions. Rotameric states of the isopropyl fragment were also characterised for the compounds studied. Distinctions in conformational states for the 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones and (−)‐menthone were revealed and are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Genetic basis of rett syndrome
Authors: Van den Veyver Ignatia B. , Zoghbi Huda Y.
Published: October 2002

The origin of Rett syndrome has long been debated, but several observations have suggested an X‐linked dominant inheritance pattern. We and others have pursued an exclusion‐mapping strategy using DNA from a small number of familial Rett syndrome cases. This work resulted in the narrowing of the region likely to harbor the mutated gene to Xq27.3‐Xqter. After systematic exclusion of several candidate genes, we discovered mutations in MECP2, the gene that encodes the transcriptional repressor, methyl‐CpG‐binding protein 2. Since then, nonsense, missense, or frameshift mutations have been found in at least 80% of girls affected with classic Rett syndrome. Sixty‐four percent of mutations are recurrent C > T transitions at eight CpG dinucleotides mutation hotspots, while the C‐terminal region of the gene is prone to recurrent multinucleotide deletions (11%). Most mutations are predicted to result in total or partial loss of function of MeCP2. There is no clear correlation between the type and position of the mutation and the phenotypic features of classic and variant Rett syndrome patients, and XCI appears to be a major determinant of phenotypic severity. Further research focuses on the pathogenic consequences of these mutations along the hypothesis of loss of transcriptional repression of a small number of genes that are essential for neuronal function in the maturing brain. MRDD Research Reviews 2002;8:82–86. © 2002 Wiley‐Liss, Inc.
Design of a SENSE‐optimized high‐sensitivity MRI receive coil for brain imaging
Authors: de Zwart Jacco A. , Ledden Patrick J. , Kellman Peter , van Gelderen Peter , Duyn Jeff H.
Published: October 2002

An 8‐channel receive‐only detector array was developed for SENSE MRI of human brain. The coil geometry was based on a gapped element design and used ultra‐high impedance preamplifiers for mutual decoupling of the elements. Computer simulations of the electric and magnetic fields showed that excellent signal‐to‐noise ratio (SNR) and SENSE performance could be achieved by placing the coil elements close to the head and maintaining a substantial gap between the elements. Measurements with a 1.5 T prototype coil showed a 2.7‐fold improvement of the SNR averaged over the brain compared to a conventional quadrature birdcage receive coil and an average geometrical noise amplification factor (g‐value) of 1.06 and 1.38 for rate‐2 and rate‐3 SENSE, respectively. Magn Reson Med 47:1218–1227, 2002. Published 2002 Wiley‐Liss, Inc.
On the timing characteristics of the apparent diffusion coefficient contrast in fMRI
Authors: Gangstead Stacey L. , Song Allen W.
Published: October 2002

For the past 10 years, functional MRI (fMRI) has seen rapid progress in both clinical and basic science research. Most of the imaging techniques are based on the blood oxygenation level‐dependent (BOLD) contrast which arises from the field perturbation of the paramagnetic deoxyhemoglobin due to the mismatch between the local oxygen demand and delivery. Because the changes of oxygenation level take place mostly in the veins, the dominant signal sources of the BOLD signal are intra‐ and extravascular proton pools of the veins. Perfusion imaging methods, developed parallel to the BOLD technique, seek to quantify the blood flow and perfusion. Recently, perfusion imaging using arterial spin tagging methods have been used to study brain function by investigating the changes of the blood flow and perfusion during brain activation, thereby generating an alternative contrast mechanism to the functional brain imaging. Since most of these methods require tagging pulse and wait time for blood to be delivered to the imaged slice, the temporal resolution may not be optimal. Dynamic intravoxel incoherent motion (IVIM) weighting schemes using apparent diffusion coefficient (ADC) contrast were suggested to image the relative changes of the in‐plane blood flow during brain function. In this report, it was demonstrated that, in addition to the spatial discrepancies of the activated areas, the time course based on the ADC contrast consistently precedes that from the BOLD contrast with timing offset on the order of 1 sec. Since arterial networks would have different spatial locations and preceding temporal characters, the findings in this report are indicative that the ADC contrast is sensitive to the arterial blood flow changes. Magn Reson Med 48:385–388, 2002. © 2002 Wiley‐Liss, Inc.
Characterization and reduction of gradient‐induced eddy currents in the RF shield of a TEM resonator
Authors: Alecci Marcello , Jezzard Peter
Published: October 2002

Radiofrequency (RF) shields that surround MRI transmit/receive coils should provide effective RF screening, without introducing unwanted eddy currents induced by gradient switching. Results are presented from a detailed examination of an effective RF shield design for a prototype transverse electromagnetic (TEM) resonator suitable for use at 3 Tesla. It was found that effective RF shielding and low eddy current sensitivity could be achieved by axial segmentation (gap width = 2.4 mm) of a relatively thick (35 μm) copper shield, etched on a kapton polyimide substrate. This design has two main advantages: first, it makes the TEM less sensitive to the external environment and RF interference; and second, it makes the RF shield mechanically robust and easy to handle and assemble. Magn Reson Med 48:404–407, 2002. © 2002 Wiley‐Liss, Inc.
Macrophage apoptosis in rat skeletal muscle treated with bupivacaine hydrochloride: Possible role of MCP‐1
Authors: Horiguchi Taisuke , Shibata Masa‐Aki , Ito Yuko , Eid Nabil A.S. , Abe Muneaki , Otsuki Yoshinori
Published: October 2002

The fate of macrophages infiltrating damaged rat skeletal muscle fibers after intramuscular injection of the anesthetic bupivacaine hydrochloride (BPVC) and the possible roles of monocyte chemoattractant protein–1 (MCP‐1) were investigated. The number of macrophages reached a maximum level at 2 days after the injection and then gradually decreased. The number of apoptotic cells detected by terminal deoxynucleotidyl transferase–mediated dUTP nick‐end labeling (TUNEL) assay was elevated at 2–4 days and decreased thereafter. In serial sections, TUNEL‐positive cells were also immunopositive for RM‐4, an antibody specific for identification of macrophages. Electron microscopy further confirmed that it was the macrophages themselves that were undergoing apoptosis. As assessed by reverse transcriptase–polymerase chain reaction (RT‐PCR), high levels of MCP‐1 mRNA in BPVC‐treated muscles were observed and positively correlated with maximum macrophage infiltration. However, the levels of MCP‐1 mRNA returned to normal low values coincident with decrease of inflammation and healing of damaged muscle fiber. Local apoptosis of macrophages, under the control of MCP‐1, may be involved in healing of BPVC‐treated muscles. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 79–86, 2002
A self‐adapting genetic algorithm for project scheduling under resource constraints
Authors: Hartmann Sönke
Published: October 2002

This papers deals with the classical resource‐constrained project scheduling problem (RCPSP). There, the activities of a project have to be scheduled subject to precedence and resource constraints. The objective is to minimize the makespan of the project. We propose a new heuristic called self‐adapting genetic algorithm to solve the RCPSP. The heuristic employs the well‐known activity list representation and considers two different decoding procedures. An additional gene in the representation determines which of the two decoding procedures is actually used to compute a schedule for an individual. This allows the genetic algorithm to adapt itself to the problem instance actually solved. That is, the genetic algorithm learns which of the alternative decoding procedures is the more successful one for this instance. In other words, not only the solution for the problem, but also the algorithm itself is subject to genetic optimization. Computational experiments show that the mechanism of self‐adaptation is capable to exploit the benefits of both decoding procedures. Moreover, the tests show that the proposed heuristic is among the best ones currently available for the RCPSP. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 433–448, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10029
Parallel NC‐algorithms for multifacility location problems with mutual communication and their applications
Authors: Averbakh Igor , Berman Oded
Published: October 2002

The generic problem studied is to locate p distinguishable facilities on a tree to satisfy upper‐bound constraints on distances between pairs of facilities, given that each facility must be located within its own feasible region, which is defined as a subtree of the tree. We present a parallel location scheme (PLS) for solving the problem that can be implemented as an NC‐algorithm. We also introduce parallel NC‐algorithms based on the PLS for the minimax versions of the problem, including the distance‐constrained p‐center problem with mutual communication. Combining the PLS and the improved Megiddo's parametric technique, we develop strongly polynomial serial algorithms for the minimax problems; the algorithms have the best complexities currently available in the literature. Efficient parallel algorithms are given for obtaining optimal regions of the facilities. © 2002 Wiley Periodicals, Inc.
A note on the traveling repairman problem
Authors: García Alfredo , Jodrá Pedro , Tejel Javier
Published: October 2002

Given a finite set of N nodes and the time required for traveling among nodes, in the traveling repairman problem, we seek a route that minimizes the sums of the delays for reaching each node. In this note, we present a linear algorithm for solving the traveling repairman problem when the underlying graph is a path, improving the Θ(N2) time and space complexity of the previously best algorithm for this problem. We also provide a linear algorithm for solving the walk problem with deadlines (WPD) on paths. © 2002 Wiley Periodicals, Inc.
Approximation algorithms for constructing wavelength routing networks
Authors: Hassin Refael , Levin Asaf
Published: October 2002

Consider a requirement graph whose vertices represent customers and an edge represents the need to route a unit of flow between its end vertices along a single path. All these flows are to be routed simultaneously. A solution network consists of a (multi)graph on the same set of vertices, such that it is possible to route simultaneously all of the required flows in such a way that no edge is used more than K times. The SYNTHESIS OF WAVELENGTH ROUTING NETWORK (SWRN) problem is to compute a solution network of a minimum number of edges. This problem has significant importance in the world of fiber‐optic networks where a link can carry a limited amount of different wavelengths and one is interested in finding a minimum‐cost network such that all the requirements can be carried in the network without changing the wavelength of a path at any of its internal vertices. In this paper, we prove that the SWRN problem is NP‐hard for any constant K (K ≥ 2). Then, we assume that GR is a clique with n vertices and we find an “almost” optimal solution network for all values of K (K = o(n)) and present a Min{(K + 1)/2, 2 + 2/(K − 1)}‐approximation algorithm for the general case and a 2‐approximation algorithm for d‐regular graphs. © 2002 Wiley Periodicals, Inc.
Unified formulation of radiation conditions for the wave equation
Authors: Krenk Steen
Published: October 2002

A family of radiation boundary conditions for the wave equation is derived by truncating a rational function approximation of the corresponding plane wave representation, and it is demonstrated how these boundary conditions can be formulated in terms of fictitious surface densities, governed by second‐order wave equations on the radiating surface. Several well‐established radiation boundary conditions appear as special cases, corresponding to different choices of the coefficients in the rational approximation. The relation between these choices is established, and an explicit formulation in terms of selected directions with ideal transmission is presented. A mechanical interpretation of the fictitious surface densities enables identification of suitable conditions at corners and boundaries of the radiating surface. Numerical examples illustrate excellent results with one or two fictitious layers with suitable corner and boundary conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Two hybrid stress membrane finite element families with drilling rotations
Authors: Geyer Sannelie , Groenwold Albert A.
Published: October 2002

Two new assumed stress membrane finite element families with two translational and one rotational degree of freedom per node are presented. The families, denoted by 8β(M) and 8β(D), are rank sufficient and invariant, and are derived using a unified Hu–Washizu like variational formulation. A recent stress mode classification method is used to illustrate the construction of the stress interpolation matrices. In each family, a number of new formulations are derived. Numerical results are presented. Copyright © 2001 John Wiley & Sons, Ltd.
Shape optimization with hybrid‐Trefftz displacement elements
Authors: Teixeira de Freitas J. A. , Cismasiu I.
Published: October 2002

The displacement model of the hybrid‐Trefftz finite element formulation is applied to the shape optimization of linear elastostatic problems. The model is based on the direct approximation of the displacements in the domain of the element and of the tractions on its boundary. The independent description of the geometry is based on the parametric description of the shape of the element sides. The finite element solving system is symmetric and sparse. As the displacement approximation is extracted from the solution set of the governing differential equations, all structural matrices are defined by boundary integral expressions. The approximation bases are compact and naturally p‐hierarchical. High‐order approximations are implemented to obtain accurate solutions using coarse meshes of macro‐elements. The sensitivities are determined analytically and remeshing is not implemented during the optimization procedure because the elements are weakly sensitive to gross shape distortion. Numerical testing is based on a standard set of two‐dimensional linear elastostatic problems. Copyright © 2001 John Wiley & Sons, Ltd.
Hybrid time domain solvers for the Maxwell equations in 2D
Authors: Abenius Erik , Andersson Ulf , Edelvik Fredrik , Eriksson Lasse , Ledfelt Gunnar
Published: October 2002

We present a new approach to time domain hybrid schemes for the Maxwell equations. By combining the classical FD‐TD scheme with two unstructured solvers, one explicit finite volume solver and one implicit finite element solver, we achieve a very efficient and flexible second‐order scheme. The second‐order accuracy of the hybrid scheme is verified through convergence studies on perfectly conducting as well as dielectric and diamagnetic circular cylinders. The numerical results also show its superiority to the FD‐TD scheme. Copyright © 2002 John Wiley & Sons, Ltd.
Free vibration of sandwich plates with laminated faces
Authors: Yuan W. X. , Dawe D. J.
Published: October 2002

Description is given of the development of a spline finite strip method for predicting the natural frequencies and modes of conventional rectangular sandwich plates. The faceplates are treated as being classically thin and may be of composite laminated construction. The core is modelled as a three‐dimensional body. Finite strip stiffness and mass properties are based on a displacement field which represents eight fundamental through‐thickness displacements as a series of products of longitudinal B‐spline functions and crosswise Lagrangian or Hermitian polynominal shape functions. The solution procedure utilizes the efficient superstrip concept in conjunction with the extended Sturm sequence‐bisection approach. A variety of applications of the developed analysis capability is described which demonstrates the nature of the convergence of the finite strip predictions of natural frequencies and the close comparison of these predictions with available results in the literature, and also the use of the capability in parametric studies. Copyright © 2002 John Wiley & Sons, Ltd.
Stress analysis in continuous media with an edge dislocation by finite element dislocation model
Authors: Sasaki Kazuaki , Kishida Michiya , Ekida Yutaka
Published: October 2002

In this paper, a finite element dislocation model is proposed, based on well‐known mathematical dislocation model. As application examples, the stress distributions around an edge dislocation in infinite homogeneous and inhomogeneous regions are calculated and compared with the analytical results. The FEM results coincide well with the exact solutions. The results show an applicability and a usefulness of finite element dislocation model, and further, a possibility of analysing a dislocation problem in finite region with complicated shapes and boundary conditions. Copyright © 2002 John Wiley & Sons, Ltd.
Modelling friction near sharp edges using a Eulerian reference frame: application to aluminium extrusion
Authors: van Rens B. J. E. , Brekelmans W. A. M. , Baaijens F. P. T.
Published: October 2002

When using a Eulerian finite element approach to model the material deformation that occurs in e.g. forming processes, the accurate capturing of friction is of crucial importance to the quality of the computational results. For the algorithm that incorporates the frictional phenomena into the system of equations, the direction of the contact surface normal in a node is an essential parameter. However, this normal is not uniquely defined in the nodes of a curved, discretized surface. Therefore, a substitute normal has to be reconstructed.

The commonly used (averaging) methods to determine the normal are either mesh or geometry dependent which renders poor results on coarse meshes. Therefore, a new method is presented that reconstructs the direction of the normal from the flow field near the node. Comparing the flow fields on a coarse mesh with those obtained on a very fine mesh reveals that a more accurate solution field is obtained using the method introduced here. Copyright © 2002 John Wiley & Sons, Ltd.