bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of food dry matter intake on the flow of amino acids at the terminal ileum for rats fed an enzyme‐hydrolysed casein‐based diet
Authors: James Kerry A C , Butts Christine A , Koolaard John P , Donaldson Helen E , Scott Margaret F , Moughan Paul J
Published: October 2002

The aim of the study was to determine whether food dry matter intake had an effect on endogenous ileal amino acid flows in the rat when the flows were expressed in units of mg g−1 dry matter. Eighty 200 g body weight rats were trained for 7 days to consume a casein‐based diet over a daily 3 h feeding period, and then an enzyme‐hydrolysed casein (MW < 5000 Da)‐based diet, with chromic oxide as an indigestible marker, was fed for a further 8 days. The mean ratio of food intake to metabolic body weight over all 80 rats was determined on days 11 and 12. On day 15, food was offered to groups of 10 rats at each of eight intake levels. The intake levels were calculated from the mean food intake value and individual metabolic body weights and scaled in increments of 0.1 by factors ranging from 0.3 to 1.0. Digesta were collected from the terminal ileum 3 h after the start of the meal, and endogenous ileal amino acid flows were determined after amino acid and Cr analyses of the diet and endogenous ileal digesta fractions prepared by centrifugation and ultrafiltration (10 000 Da molecular weight cut‐off). The linear regression relationships between ileal amino acid flows, expressed as mg g−1 dry matter, and dry matter intakes demonstrated that all slopes were negative but that the slopes for nine of these amino acids were not significantly different from zero (P > 0.05). There were significant slopes (P < 0.05) for the other eight amino acids, although the magnitudes of the effect were small. When the data were re‐examined after removing the lowest feeding level, the slopes for most of these amino acids were no longer statistically significant. The results showed that the measures of amino acid flow (mg g−1 dry matter), except for isoleucine and cystine, over a wide range of food intakes were not materially affected by food intake. From the perspective of bioassay logistics the results indicate that expressing ileal amino acid flows proportional to dry matter intake is justified over the range of intakes found in practice for determining true ileal amino acid digestibility by the enzyme‐hydrolysed casein method.

© 2002 Society of Chemical Industry
A comparison of the nutrient digestibility of Desi and Kabuli chickpeas fed to swine
Authors: Thacker Philip A , Qiao Shiyan , Racz Vernon J
Published: October 2002

An experiment was conducted to compare the nutritional composition of 16 varieties of chickpeas (Kabuli and Desi) and to determine their nutrient digestibility for swine using the mobile nylon bag technique. The average crude protein content of the Kabuli chickpeas (226 g kg−1) was lower than that of the Desi chickpeas (235 g kg−1). Desi chickpeas were higher in acid detergent fibre (145 versus 50 g kg−1) and neutral detergent fibre (264 versus 181 g kg−1) than Kabuli chickpeas. Digestibility coefficients for dry matter (83.1 versus 72.5%), gross energy (83.5 versus 74.8%) and crude protein (83.7 versus 79.4%) were higher for Kabuli chickpeas than for Desi chickpeas. Based on chemical analysis and nutrient digestibility, Kabuli chickpeas would appear to have greater potential as a protein and energy source for use in swine rations than Desi chickpeas.

© 2002 Society of Chemical Industry
Degradation and physicochemical changes of barley and pea fibre along the gastrointestinal tract of pigs
Authors: Canibe Nuria , Bach Knudsen Knud Erik
Published: October 2002

The degradation of barley and pea fibres along the gastrointestinal tract (GIT) of pigs and its relation to changes in some of their physicochemical properties were investigated. Ileal and caecal digesta containing pea cotyledon fibre showed the highest (P < 0.05) swelling (33.1–36.7 ml g−1 DM) and water retention capacity measured by centrifugation (17.9–21.2 g g−1 DM) and by osmotic pressure (9.0–9.1 g g−1 DM). The particle size of barley hull did not change along the GIT (160–207 µm), whereas that of pea cotyledon and pea hull was drastically reduced in faeces (62–65 µm) compared with the ileum and caecum (198–415 µm). The digestibility of non‐starch polysaccharides (NSP) was lowest for barley hull in the ileum (5% of intake), caecum (0% of intake) and faeces (26% of intake). The digestibility of NSP was highest for pea cotyledon fibre and dehulled barley in the proximal hindgut and for pea cotyledon fibre in faeces (96% of intake for pea cotyledon vs 74–82% of intake for dehulled barley and pea hull). In conclusion, hydration properties and particle size add valuable information when describing the fermentation of fibres in the GIT. However, they cannot be used alone as indicators of the extent of fermentation of different fibres. The results also suggested that the fibre source and the organisation and lignification of the cell walls lead to different fermentation processes along the GIT of pigs.

© 2001 Society of Chemical Industry
Silicon deprivation and arginine and cystine supplementation affect bone collagen and bone and plasma trace mineral concentrations in rats
Authors: Seaborn C.D. , Nielsen F.H.
Published: October 2002

Because arginine has been established as an essential amino acid for collagen formation, and several bone‐remodeling proteins are rich in cysteine, we performed a study to ascertain whether supplemental arginine (Arg) and cystine (Cys) would affect bone collagen and mineral composition changes in animals deprived of silicon (Si). Male weanling Sprague‐Dawley rats were randomly assigned to treatment groups of 12 in a 2 × 2 factorially arranged experiment. The rats were fed for 9 weeks a basal casein–ground corn–corn oil diet containing per g 2 μg Si, 1.7 mg Cys, 4.7 mg methionine, and 7.8 mg Arg. The independent treatment variables, per g fresh diet, were supplemental Si (as sodium metasilicate) at 0 and 35 μg and Cys or Arg at 0 and 12 mg. Silicon deprivation decreased the concentration of hydroxyproline in femur and potassium in vertebra. An interaction between Si and amino acid supplementation affected hematocrit, liver iron concentration, and bone copper and manganese concentrations. In animals deprived of Si, Cys supplementation compared to Arg supplementation depressed hematocrit, liver iron concentration, and tibia and vertebral copper concentrations and increased tibia and vertebral manganese concentrations. On the other hand, in animals fed adequate Si, supplemental Cys compared to supplemental Arg increased hematocrit, liver iron concentration, and tibia and vertebral copper concentrations and decreased tibia and vertebral manganese concentrations. Dietary Si also influenced the effect of Cys on mineral composition of the vertebra. The calcium and phosphorus concentrations in the vertebra were markedly increased by supplemental Cys compared to supplemental Arg when dietary Si was inadequate but had no effect on these concentrations when dietary Si was adequate. These findings indicate that silicon is needed for collagen formation, that high dietary Cys enhances changes induced by Si deprivation in trabecular‐rich bone, and that Si nutriture has more impact on trabecular‐rich bone than in cortical‐rich bone. J. Trace Elem. Exp. Med. 15:113–122, 2002. Published 2002 Wiley‐Liss, Inc.
Black and Decker—towards a knowledge‐centric organization
Authors: Pemberton J. D. , Stonehouse G. H. , Francis M. S.
Published: October 2002

Black and Decker, like other global organizations, has sought to capitalize on its knowledge assets to enhance its international competitive performance. In this paper, attention is focused specifically on the knowledge environment at its European Design Centre (EDC), responsible for the design and introduction of new global products. The findings, derived from interviews with senior managers and a questionnaire‐based knowledge audit, reveal that the EDC is well served in terms of technological infrastructure. At the same time, there is evidence that knowledge creation and management could be enhanced by developments in the organization's human and cultural infrastructure, leadership and communications that promote the value of knowledge and integrate it within its core business. At present, these act as inhibitors to the development of a knowledge‐centric organization. Progess is, however, being made in this respect, with the appointment of a knowledge executive and the introduction of in‐house initiatives designed to facilitate the sharing and creation of knowledge. Such developments signal Black and Decker's commitment to ensuring that knowledge, both individual and organizational, is embedded within the company's core business and that it emerges as a truly knowledge‐centric organization. Copyright © 2002 John Wiley & Sons, Ltd.
Integrating knowledge management applications in the enterprise—the Xerox Knowledge Portal project
Authors: Schwabe Daniel , Salim César Simões
Published: October 2002

In this paper we describe the design and deployment of an Enterprise Knowledge Portal in the Brazilian subsidiary of the Xerox Corporation. The first unique feature of this project is the use of the Object Oriented Hypermedia Design Method (OOHDM) as a tool to design a portal, which is seen as an instance of a Web‐based Knowledge Management application. The second unique feature is the use of a customized business game devised to trigger changes in corporate culture that lead to the adoption of the portal as a tool to support everyday activities. We describe the technical specification of the portal as a Web application, and discuss the business game and its deployment, reporting on the experience gathered from the whole project. Copyright © 2002 John Wiley & Sons, Ltd.
Scanning laser system for photodynamic therapy of choroidal neovascularization
Authors: Obana Akira , Gohto Yuko
Published: October 2002

Background and Objectives

In order to improve selectivity of photodynamic therapy (PDT) to choroidal neovascularization (CNV) associated with age‐related macular degeneration, a laser scanning technique was applied to perform focal laser irradiation to the retina, and the occlusion effects of a new device to the choriocapillaris were evaluated in primate eyes.

Study Design/Materials and Methods

The device contains lasers for fundus observation of 785 nm and for PDT of 670 nm, matching the absorption peak of a photosensitizer, ATX‐S10(Na). The laser irradiated the shape on the retina specified before treatment and shut off automatically when the predetermined treatment was achieved. The occlusion of the choriocapillaris after PDT was documented by fluorescein and indocyanine green angiography and histology.

Results

The area designated for PDT was easily drawn on the touch‐screen monitor, and occlusion of the choriocapillaris was achieved precisely in the area pre‐selected for treatment with 5 J/cm2 or more of radiance following administration of 8 mg/kg ATX‐S10(Na).

Conclusions

This device is useful for irradiating CNV of any shape, sparing the surrounding retina. Since our previous studies suggested that selective occlusion of CNV would decrease not only the functional disturbance caused by PDT, but also the recurrence of CNV, the present device may allow more effective PDT than the slit‐lamp system presently used. Lasers Surg. Med. 30:370–375, 2002. © 2002 Wiley‐Liss, Inc.
Steele‐Richardson‐Olszewski‐Syndrome: Reduction of dopamine D2 receptor binding relates to the severity of midbrain atrophy in vivo: 123IBZM SPECT and MRI study
Authors: Arnold Guy , Tatsch Klaus , Kraft Eduardo , Oertel Wolfgang H. , Schwarz Johannes
Published: October 2002

Patients with the clinical diagnosis of progressive supranuclear palsy (PSP) show heterogeneous neuropathological findings. In neuropathologically proven cases with numerous neurofibrillary tangles of neuropil threads, the brainstem and striatum are always affected. We compared 123I‐iodobenzamide single photon emission computed tomography (IBZM‐SPECT) for imaging of striatal dopamine D2 receptors in vivo with high‐resolution magnetic resonance imaging (MRI) in 13 patients with possible or probable PSP. Clinically, all patients exhibited similar signs including supranuclear vertical–down‐gaze palsy, axial rigidity especially involving the neck, bradykinesia, instability of balance with easy falls, and a poor response to dopaminergic drugs.

Specific striatal dopamine D2 receptor binding in IBZM‐SPECT was reduced in 10 patients but was normal in three patients. Mean midbrain diameter was 23.7 mm. The reduction of IBZM‐binding was statistically significantly correlated to midbrain atrophy (P = 0.010) either in all 13 patients or in those without striatal or white matter lesions (P = 0.015). We suggest that technical investigations, mainly MRI, are able to corroborate the in vivo diagnosis, if PSP is clinically suspected. © 2002 Movement Disorder Society.
Reaction time is not impaired by stimulation of the ventral‐intermediate nucleus of the thalamus (Vim) in patients with tremor
Authors: Flament Didier , Shapiro Mark B. , Pfann Kerstin D. , Moore Charity G. , Penn Richard D. , Corcos Daniel M.
Published: October 2002

We studied the effect of high‐frequency electrical stimulation of the ventral‐intermediate nucleus of the thalamus (Vim) in four patients implanted with chronic stimulators to determine whether this procedure adversely affects reaction time to a proprioceptive stimulus. Two patients had undergone this surgery for treatment of tremor resulting from Parkinson's disease insufficiently responsive to levodopa therapy and two patients for treatment of essential tremor. Reaction times to auditory, visual, cutaneous, and proprioceptive stimuli were tested in a simple motor task requiring flexion of the elbow joint to a visual target in response to each stimulus. Reaction times were tested postoperatively with and without the stimulator turned on. We found that reaction time for all stimulus modalities was not increased when the stimulator was turned on; in fact, reaction times were, on average, slightly shorter during stimulation, but this difference was not statistically significant. We conclude that transmission of somatosensory inputs, necessary for initiating voluntary movement, from the periphery to the cortex is not significantly impaired by stimulation of the ventral‐intermediate nucleus of the thalamus in patients with pathological tremor. © 2002 Movement Disorder Society
Analysis of circular microstrip antennas on low‐ and high‐relative‐permittivity substrates
Authors: Verma A. K. , Nasimuddin
Published: October 2002

A simple and accurate cavity model called the modified Wolff model (MWM) is presented to compute the resonance frequency and input impedance of the circular microstrip antenna on the PTFE, alumina, and GaAs substrates. Results of the MWM show better agreement with the experimental results as compared to results of the commercial software; namely, the standard cavity model adopted in the PCAAD, the multiport cavity model (MCM), and the method‐of‐moments– (MOM) based Ensemble. The MWM works with high accuracy on both the thin and thick substrates and from microwave to millimeter‐wave range. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 75–80, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10377
Neural network with knowledge‐based neurons for the modeling of crossover discontinuities in stripline circuits
Authors: Hong J. S. , Wang B. Z. , Hu B. J. , Liu Y. W.
Published: October 2002

A novel three‐layer neural network with knowledge‐based neurons in hidden layer (NNKBN) has been applied to model the crossover discontinuities in stripline circuits. The NNKBN model is electromagnetically developed with a set of data that are produced by the full‐wave finite‐difference–time‐domain method. Numerical experiments show that the NNKBN model has many advantages over the conventional multilayer perceptron model. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 107–109, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10387
Planar L‐strip fed broadband microstrip antenna
Authors: Mridula S. , Menon Sreedevi K. , Lethakumary B. , Paul Binu , Aanandan C. K. , Mohanan P.
Published: October 2002

A broadband rectangular microstrip antenna utilizing an electromagnetically coupled L‐strip feed is presented. Experimental study shows a 2:1 VSWR bandwidth of ≈ 10% and excellent cross‐polarization performance with a radiation coverage almost as same as that of the rectangular microstrip antenna fed by conventional methods. The variation of bandwidth for different feed parameters is also studied. The proposed antenna is suitable for broadband communications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 115–117, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10390
Radiation efficiency and impedance bandwidth of conductor‐backed CPW‐FED slot dipole antenna with two‐layered dielectric substrate
Authors: Jacobs J. P. , Joubert J. , Odendaal J. W.
Published: October 2002

Radiation efficiency and impedance bandwidth of optimally matched conductor‐backed coplanar waveguide‐fed slot dipoles on two‐layer substrates are investigated as a function of bottom substrate layer height. It is demonstrated that low radiation efficiency due to parasitic parallel‐plate modes may be notably improved through increased height of the bottom layer at the cost of decreasing bandwidth. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 138–141, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10396
A comparison study of EM and physical equivalent circuit modeling for MIM CMOS capacitors
Authors: Xiong X. Z. , Fusco V. F.
Published: October 2002

In this Letter a new physical model for metal–insulator–metal CMOS capacitors is presented. In the model the parameters of the circuit are derived from the physical structural details. Physical behaviors due to metal skin effect and inductance have been considered. The model has been confirmed by 3D EM simulator and design rules proposed. The model presented is scalable with capacitor geometry, allowing designers to predict and optimize quality factor. The approach has been verified for MIM CMOS capacitors. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 177–181, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10409
Robust application of the complex images technique to the full‐wave analysis of slot‐like transmission lines
Authors: Bernal Joaquín , Medina Francisco , Boix Rafael R.
Published: October 2002

In this Letter, the mixed potential integral equation (MPIE) method is used in conjunction with the complex images technique to carry out a full‐wave analysis of a multiconductor coplanar waveguide (CPW) embedded in a layered substrate. Special attention is paid to the correct application of the method so as to maintain high accuracy and stability of the numerical results. It is shown that the procedure only provides a robust and accurate approach when the complex images expansion variable is properly chosen and the singularities of the Green's functions are properly handled. Numerical problems arise in any other case. In particular, it is demonstrated that the two‐level sampling scheme used by some authors is not enough to overcome the numerical problems. However, the two‐level sampling method is shown to be essential to deal with the presence of extremely thin substrate layers such as those found in multichip‐module‐deposition (MCM‐D) technologies. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 198–203, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10416
Applications of hybrid discrete Fourier transform moment method to the fast analysis of large rectangular dipole arrays printed on a thin grounded dielectric substrate
Authors: Chou Hsi‐Tseng , Ho Hsien‐Kwei , Civi O. A. , Erturk Vakur B.
Published: October 2002

Recently a discrete Fourier transform–method of moments (DFT‐MoM) scheme was developed for fast analysis of electrically large rectangular planar dipole arrays, which has been shown to be very efficient in terms of number reduction of unknown variables and computational complexity. The applications of this DFT‐MoM to treat dipole arrays printed on a grounded dielectric substrate are examined in this Letter. Numerical results are presented to validate its efficiency and accuracy. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 203–207, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10417
Wideband finite‐difference–time‐domain beam propagation method
Authors: Lim J. J. , Benson T. M. , Larkins E. C. , Sewell P.
Published: October 2002

A wide‐band finite‐difference–time‐domain beam propagation method (FD TD‐BPM) based on Padé approximants is introduced to improve the bandwidth of the conventional TD‐BPM. Numerical dispersion relations for the TD‐BPM are derived to demonstrate the increase in bandwidth of the wide‐band TD‐BPM. The effects of the spatial and time step sizes on the numerical dispersion are also investigated. It is shown that the wide‐band TD‐BPM is less sensitive to the choice of spatial step size and allows a larger time step size to be used compared to the finite‐difference time‐domain (FD‐TD) method. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 243–247, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10428
Multimedia applications using optical FFH‐CDMA communication systems
Authors: Thiruchelvi M. , Meenakshi M. , Geetha G.
Published: October 2002

In this Letter multimedia transmission in an optical‐fiber network using a fast frequency hopping–code division multiple access scheme is discussed. The multirate one coincidence variable length frequency hop patterns have been generated and their auto‐ and cross‐correlation properties are studied. A series of multiple Bragg gratings in a single optical fiber has been proposed to implement the encoder and decoder. Bit‐error‐rate analysis assuming Gaussian approximation for the error probability has been carried out. The results of the numerical analysis reveal that this system can support up to 30 simultaneous users with two different data rates (e.g., 500 Mbps and 2 Gbps). It can be concluded from the results that the fast frequency hopping–optical code division multiple access system is capable of supporting multimedia applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 259–263, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10432
A novel algorithm for high sensitivity in measuring surface variation based on volume holography
Authors: Sun Ching‐Cherng , Hsu Chih‐Yuan , Su Wei‐Chia , Ouyang Yuh , Chang Jenq‐Yang
Published: October 2002

A novel design for the precise measurement of surface variation based on volume holography is proposed. The volume hologram is a spatial filter, which records the index grating corresponding to the interference fringes by a plane wave and a divergent spherical wave. In the measuring process, a point source attached to a probe is used to read the hologram. A precise measurement can be achieved because the horizontal displacement of the point source is very sensitive to the hologram. This sensitivity is higher than that of a holographic confocal microscopy based on the longitudinal displacement. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 319–321, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10448
Acute arrhythmogenicity of first‐dose chemotherapeutic agents in children
Authors: Massin Martial M. , Dresse Marie‐Françoise , Schmitz Véronique , Hoyoux Claire , Chantraine Jean‐Marie , Lepage Philippe
Published: October 2002

Background

Chemotherapeutic agents have been reported to cause severe arrhythmias and sudden death in the first 24 hr after administration. In this prospective study, we determined the magnitude of acute arrhythmogenicity of those agents in children.

Procedure

Thirty‐three patients with diverse malignancies (leukemia n = 16, Wilms tumor n = 3, brain tumor n = 3, lymphoma n = 3, others n = 8) were studied with Holter monitors 24 hr before, during, and in the first 24 hr following the first‐dose therapy.

Results

Two patients experienced conduction disturbances (phases of 2nd degree sinuatrial and atrioventricular blocks) during a 4‐hr period corresponding to a 30 mg/m2 daunorubicin infusion. Eight patients experienced supraventricular extrasystoly (SE), ventricular extrasystoly (VE), and/or short salvos of supraventricular (SVT) and/or ventricular tachycardia (VT). Six had leukemia (therapy: daunorubicin + vincristine), one had a lymphoma (therapy: vincristine + cyclophosphamide), and the last one a brain tumor (therapy: carboplatin + procarbazine). Three patients with leukemia had pretreatment arrhythmias (1 VT, 2 SVT). One of them and the five other patients had arrhythmias during and after the first‐dose therapy (2 VE, 2 SVT, 1 SVT + VE, 1 VE + SE + SVT). No patient had life‐threatening arrhythmias and no prognostic value of those disturbances could be demonstrated.

Conclusions

Conduction disturbances and arrhythmias are common in cancer children at the beginning of the therapy, but no acute or long‐term adverse consequences are related to their appearance. Med Pediatr Oncol 2002;39:93–98. © 2002 Wiley‐Liss, Inc.
Normal monocyte‐derived dendritic cell function in patients with langerhans‐cell‐histiocytosis
Authors: Holter Wolfgang , Ressmann Gabriele , Grois Nicole , Lehner Manfred , Parolini Ornella , Gadner Helmut
Published: October 2002

Background

Langerhans cell histiocytosis (LCH) is a histiocytic disease, characterized by the lesional accumulation of dendritic Langerhans cells together with T cells and eosinophils. The cause of this disease is unknown. Langerhans cells are bone marrow‐derived dendritic cells (DCs), which can develop from CD34+ hematopoietic progenitor cells as well as from monocytes.

Procedure

To test whether LCH patients have a general functional defect present in cells of their DC lineage, we generated immature DCs by culturing monocytes from nine patients with single‐ or multisystem LCH with GM‐CSF and IL‐4, and analyzed their phenotype and function before and after an in vitro maturation stimulus. Immature DCs were analyzed for their phenotype and cytokine production, DCs matured in response to TNF‐α plus PGE2 were analyzed for their phenotype, their stimulatory capacity in MLR, cell aggregation, and activation‐induced apoptosis.

Results

In summary, no difference was found between both immature as well as mature DCs generated from patients and controls regarding the expression of CD1a, CD80, CD86, MHC class I, and MCH class II antigens. Similarly, no difference was found regarding IL‐10, ‐12, and TNF‐α production, as well as regarding cell aggregation and apoptosis in response to external stimuli.

Conclusions

The absence of gross functional abnormalities in DCs generated from monocytes from patients with LCH makes the existence of a severe functional defect affecting all cells of the DC lineage in these patients unlikely. Med Pediatr Oncol 2002;39:181–186. © 2002 Wiley‐Liss, Inc.
Structure of a calotropagenin‐derived artifact from Calotropis procera
Authors: Hanna Atef G. , Shalaby Nagwa M. M. , Morsy Nagy A. M. , Simon András , Tóth Gábor , Malik Shahid , Duddeck Helmut
Published: October 2002

Isolation of a new artifact (1) from Calotropis procera is reported which, apparently, is formed from the precursor calotropagenin (4) when exposed to methanol during work‐up. In addition, two more known cardenolides (2 and 3) could be identified. The structure of 1 and its full 1H and 13C signal assignment were accomplished by 1D and 2D NMR techniques. Copyright © 2002 John Wiley & Sons, Ltd.
Neurophysiology of Rett syndrome
Authors: Glaze Daniel G.
Published: October 2002

Neurophysiological evaluations have been widely applied in the study of Rett syndrome (RS) to provide information concerning the developmental aspects of RS; the character and extent of involvement of the central, peripheral, and autonomic nervous system pathways; and evaluation of the clinical symptomatology of RS. The electroencephalogram (EEG) is invariably abnormal and shows characteristic, though not diagnostic, changes: loss of expected developmental features; the appearance of focal, multifocal, and generalized epileptiform abnormalities; and the occurrence of rhythmic slow (theta) activity primarily in the frontal‐central regions. Epileptic seizures are reported to occur frequently in RS, and partial and generalized seizures may be experienced by RS girls. However, many events presumed to be seizures have no EEG correlate during video‐EEG monitoring, suggesting the possibility of a nonepileptic mechanism. Such monitoring may be necessary to determine appropriate use of antiepileptic drugs. Evoked potentials typically demonstrate intact peripheral auditory and visual pathways and suggest dysfunction of central or “higher” cortical pathways. Somatosensory‐evoked potentials may be characterized by “giant” responses, suggesting cortical hyperexcitability. An increased incidence of long QT intervals during electrocardiographic recordings and diminished heart‐rate variability, suggesting impairment of the autonomic nervous system, are described in RS. With the discovery of the genetic basis of RS, neurophysiological studies will provide parameters for phenotype‐genotype correlations and characterization of animal models. MRDD Research Reviews 2002;8:66–71. © 2002 Wiley‐Liss, Inc.
Study of the effect of CSF suppression on white matter diffusion anisotropy mapping of healthy human brain
Authors: Papadakis Nikos G. , Martin Kay M. , Mustafa Mohammed H. , Wilkinson Iain D. , Griffiths Paul D. , Huang Chris L.‐H. , Woodruff Peter W.R.
Published: October 2002

Healthy human brain diffusion anisotropy maps derived from standard spin echo diffusion tensor imaging (DTI) were compared with those using fluid‐attenuated inversion recovery (FLAIR) preparation prior to DTI to null the signal from cerebrospinal fluid (CSF). Consistent comparisons entailed development of DTI postprocessing methods, image masking based on fitting quality, and an objective region‐of‐interest‐based method for assessment of white matter extent. FLAIR DTI achieved an extended delineation of major white‐matter tracts (genu, splenium, and body of the corpus callosum) close to large CSF‐filled spaces (lateral ventricles), but did not affect representation of tracts remote from CSF (internal and external capsules and coronal radiation). This result, which was detectable qualitatively (visual inspection), was verified quantitatively by analyses of the relative anisotropy (RA) distribution over white matter structures for 11 subjects. FLAIR DTI thus suppresses the CSF signal that otherwise masks underlying anisotropic parenchymal tissue through partial volume averaging. Magn Reson Med 48:394–398, 2002. © 2002 Wiley‐Liss, Inc.
Contractile muscle volume and agonist‐antagonist coactivation account for differences in torque between young and older women
Authors: Macaluso Andrea , Nimmo Myra A , Foster John E. , Cockburn Muriel , McMillan Nigel C. , De Vito Giuseppe
Published: October 2002

It is controversial whether specific tension (the ratio between muscle strength and size) declines with aging. Therefore, contractile muscle volume was estimated separately from the intramuscular noncontractile tissue by magnetic resonance imaging, and maximum isometric torque was measured in the knee extensors and flexors of 10 young (22.8 ± 5.7 years) and 10 older (69.5 ± 2.4 years) healthy active women. Specific tension was lower in the older women both in the extensors (93.1 ± 20.1 kN·m−2 vs. 112.1 ± 12.3 kN·m−2; P < 0.05) and in the flexors (100 ± 31 kN·m−2 vs. 142.7 ± 23.9 kN·m−2; P < 0.01). This was accompanied by an increase in the percentage coactivation of the knee flexors during knee extension. These data suggest that the lower level of muscle torque in the older women can be explained not only by smaller contractile muscle mass but also by increased coactivation of the antagonist muscles during knee extension. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
New evidence for a presynaptic action of prednisolone at neuromuscular junctions
Authors: Dal Belo Cháriston André , Leite Gildo Bernardo , Fontana Marcos Dias , Corrado Alexandre Pinto , Zanandréa Baso Ana Cristina , Moreno Serra Carmen Sílvia , Oliveira Antonio Carlos , Rodrigues‐Simioni Léa
Published: October 2002

The action of prednisolone at the neuromuscular junction was studied in mouse isolated phrenic nerve–diaphragm and rat external popliteal/sciatic nerve–tibialis anterior muscle preparations. Prednisolone (0.03 mM and 0.3 mM) did not alter the twitch‐tension in phrenic nerve–diaphragm preparations after 120 min, but increased the frequency (170 ± 4%) and amplitude (200 ± 13%) of miniature end‐plate potentials. Quantal content was not influenced by the glucocorticoid treatment. Prednisolone (400 μg/kg) did not change the twitch‐tension in rat external popliteal/sciatic nerve–tibialis anterior muscle preparations. However, this steroid (0.3 mM) prevented the neuromuscular blockade by d‐tubocurarine (1.45 μM) in mouse preparations by 70 ± 10% (P < 0.05). A similar effect (82 ± 6% protection, P < 0.05) occurred in rats treated with prednisolone (400 μg/kg) before d‐tubocurarine (225 μg/kg). In phrenic nerve–diaphragm preparations, prednisolone (0.3 mM) increased (13 ± 4%, p < 0.05) the twitch‐tension in the presence of β‐bungarotoxin (1 μM), and prevented the blockade produced by this toxin (0.15 μM) in its third phase of action. This presynaptic facilitatory effect may contribute to the usefulness of prednisolone in myasthenia gravis. © 2002 Wiley Periodicals, Inc. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 37‐43, 2002
Differential fatigue of paralyzed thenar muscles by stimuli of different intensities
Authors: Godfrey Sharlene , Butler Jane E. , Griffin Lisa , Thomas Christine K.
Published: October 2002

Muscles paralyzed by injury or disease fatigue excessively when stimulated. This study examined whether the first few paralyzed thenar motor units recruited by electrical stimulation of the median nerve were more fatigue resistant than the total thenar motor unit population. The paralyzed thenar muscles of four subjects with chronic cervical spinal cord injury were fatigued by a 2‐min intermittent 40‐HZ protocol on 2 days. One experiment involved submaximal stimulation, the other supramaximal stimulation. These stimuli resulted in activation of part and all of the thenar muscles, respectively. Relative force loss, force–time integral decline, and slowing of half‐relaxation time were always significantly less when only part rather than all of the muscles was fatigued. The part of the paralyzed muscles that was activated was also relatively fatigue resistant compared with control single thenar motor units. Thus, a reversal of recruitment order from fatigable to fatigue‐resistant units cannot explain the extreme fatigability of paralyzed muscles. Use of submaximal stimulation during functional electrical stimulation may therefore help to reduce muscle fatigue because it recruits the more fatigue‐resistant units. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 122–131, 2002
Partial conduction blocks in N‐hexane neuropathy
Authors: Pastore Carlos , Izura Virginia , Marhuenda Dolores , Prieto María‐José , Roel José , Cardona Antonio
Published: October 2002

Nerve conduction blocks, defined by a significant reduction in amplitude or area of the compound muscle action potential at proximal compared with distal sites of stimulation, have been described in glue‐sniffers and in workers with industrial exposure at an early stage of n‐hexane neuropathy. The frequency with which this focal conduction anomaly appears is described and discussed in the case of a very homogeneous group of 10 young workers diagnosed with n‐hexane polyneuropathy. Partial conduction blocks occurred in only two workers and may have been related to the intensity and duration of toxic exposure. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 132–135, 2002
Note on “deterministic inventory lot‐size models under inflation with shortages and deterioration for fluctuating demand” by Yang et al.
Authors: Skouri K. , Papachristos S.
Published: October 2002

In a recent paper Yang et al. extended the lot‐size models to allow for inflation and fluctuating demand. For this model they proved that the optimal replenishment schedule exists and is unique. They also proposed an algorithm to find the optimal policy. The present paper provides examples, which show that the optimal replenishment schedule and consequently the overall optimal policy may not exist. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 527–529, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10022
Activin and bone morphogenetic proteins are present in perinatal sensory neuron target tissues that induce neuropeptides
Authors: Hall Alison K. , Burke Rebecca M. , Anand Malini , Dinsio Kyl J.
Published: October 2002

Previous studies have shown that sensory target tissues induce neuropeptides in naïve sensory neurons, and that activin and bone morphogenetic proteins (BMPs) are capable of inducing neuropeptides associated with nociception in embryonic sensory neurons in vitro. The goal of the present study was to learn if these ligands were available in native sensory neuron target tissues at correct developmental periods to play this inductive role in vivo. Sensory neurons initially contact their peripheral target tissues and begin to express neuropeptides during late embryogenesis, and we demonstrate that activin and BMPs are present in the embryo and neonate to regulate sensory neuron differentiation. Native embryonic and neonatal target tissues were analyzed by immunoblot and immunohistochemical studies using ligand‐specific antibodies. Although activin was easily solubilized, BMPs were detected only after high salt extraction, suggesting that BMPs were bound to extracellular moieties and were capable of acting only locally in native tissues. One inhibitor, noggin, was present in both embryonic skin and muscle. In combination, these data suggest that neuronal differentiation is unlikely to be regulated by simple expression of ligand, but that the functional availability of ligand is a critical component confering biological activity. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 52–60, 2002
On the formulation of closest‐point projection algorithms in elastoplasticity—part II: Globally convergent schemes
Authors: Pérez‐Foguet A. , Armero F.
Published: October 2002

This paper presents the formulation of numerical algorithms for the solution of the closest‐point projection equations that appear in typical implementations of return mapping algorithms in elastoplasticity. The main motivation behind this work is to avoid the poor global convergence properties of a straight application of a Newton scheme in the solution of these equations, the so‐called Newton‐CPPM. The mathematical structure behind the closest‐point projection equations identified in Part I of this work delineates clearly different strategies for the successful solution of these equations. In particular, primal and dual closest‐point projection algorithms are proposed, in non‐augmented and augmented Lagrangian versions for the imposition of the consistency condition. The primal algorithms involve a direct solution of the original closest‐point projection equations, whereas the dual schemes involve a two‐level structure by which the original system of equations is staggered, with the imposition of the consistency condition driving alone the iterative process. Newton schemes in combination with appropriate line search strategies are considered, resulting in the desired asymptotically quadratic local rate of convergence and the sought global convergence character of the iterative schemes. These properties, together with the computational performance of the different schemes, are evaluated through representative numerical examples involving different models of finite‐strain plasticity. In particular, the avoidance of the large regions of no convergence in the trial state observed in the standard Newton‐CPPM is clearly illustrated. Copyright © 2001 John Wiley & Sons, Ltd.
On the computation of stress fields on polygonal domains with V‐notches
Authors: Helsing Johan , Jonsson Anders
Published: October 2002

The interior stress problem is solved numerically for a single‐edge notched specimen under uniaxial load. The algorithm is based on a modification of a Fredholm second‐kind integral equation with compact operators due to Muskhelishvili. Several singular basis functions for each of the seven corners in the geometry enable high uniform resolution of the stress field with a modest number of discretization points. As a consequence, notch stress intensity factors can be computed directly from the solution. This is an improvement over other procedures where the stress field is not resolved in the corners and where notch stress intensity factors are computed in a roundabout way via a path‐independent integral. Numerical examples illustrate the superior stability and economy of the new scheme. Copyright © 2001 John Wiley & Sons, Ltd.
Multifrontal incomplete factorization for indefinite and complex symmetric systems
Authors: Qu Yong , Fish Jacob
Published: October 2002

A new class of preconditioners based on the adaptive threshold incomplete multifrontal factorization for indefinite and complex symmetric systems is developed. Numerical experiments consisting of the 3D Helmholtz equations, fluid–structure interaction and localization problems demonstrate the excellent performance of the preconditioner. Copyright © 2001 John Wiley & Sons, Ltd.
Hierarchical model adaptivity in finite element analysis for non‐linear plate problems
Authors: Fu Kang
Published: October 2002

Based on the polynomial series expansion of kinematic fields throughout the thickness of a plate, hierarchical models are constructed by selected truncations. The models are formulated with the three‐dimensional second Piola–Kirchhoff stress and Green–Lagrange strain at large deformation. The adaptivity of the models in the framework of finite element method is devised for not only the compatible combination of the elements of different models but also the evolution of the models in an element when the function of its interested property changes during analysis procedures. The key idea in the method is to meet the continuity requirement of the primary displacement field by fixing a set of common active hierarchical expansion degrees of freedom for each node, which may be shared by the elements of different models. The von Mises criterion is used here to describe material plasticity. Unilateral contact phenomena are examined on the upper and/or lower surfaces of the plates by using a penalty method. Friction effects are taken into account with a regularized Coulomb law. Examples on the numerical simulation of sheet metal forming and the analysis of a cracked plate are included to illustrate the advantage of this new strategy. Copyright © 2001 John Wiley & Sons, Ltd.
Second‐order optimal control algorithm for complex systems
Authors: Kaplan Matthew L. , Heegaard Jean H.
Published: October 2002

The solution to large‐scale optimal control problems, characterized by complex dynamics and extended time periods, is often computationally demanding. We present a solution algorithm with favourable local convergence properties as a way to reduce simulation times. This method is based on using a trapezoidal direct collocation to convert the differential equations into algebraic constraints. The resulting constrained minimization problem is then solved with an augmented Lagrangian formulation to accommodate both equality and inequality constraints. In contrast to the prevalent optimal control software implementations, we calculate analytical first and second derivatives. We then apply a generalized Newton method to the augmented Lagrangian formulation, solving for all unknowns simultaneously. The computational costs of the Hessian formation and matrix solution remain manageable as the system size increases due to the sparsity of all tensor quantities. Likewise, the total iterations for convergence scale well due to the local quadratic convergence of the generalized Newton method. We demonstrate the method with an inverted pendulum problem and a neuromuscular control problem with complex dynamics and 18 forcing functions. The optimal control solutions are successfully found. In both examples, we obtain quadratic convergence rates in the neighbourhood of the solution. Copyright © 2002 John Wiley & Sons, Ltd.
Dual‐mixed p and hp finite elements for elastic membrane problems
Authors: Bertóti E.
Published: October 2002

A complementary energy‐based, dimensionally reduced plate model using a two‐field dual–mixed variational principle of non‐symmetric stresses and rotations is derived. Both the membrane and bending equilibrium equations, expressed in terms of non‐symmetric mid‐surface stress components, are satisfied a priori introducing first‐order stress functions. It is pointed out that (i) the membrane‐, shear‐ and bending energies of the plate written in terms of first‐order stress functions are decoupled, (ii) although unmodified 3‐D constitutive equations are applied, the energy parts do not contain the 1/(1‐2ν) term for isotropic, linearly elastic materials. These facts mean that the finite element formulation based on the present plate model should be free from shear locking when the thickness tends to zero and free from incompressibility locking when the Poisson ratio ν converges to 0.5, irrespective of low‐order h‐, or higher‐order p elements are used.

Curvilinear dual‐mixed hp finite elements with higher‐order stress approximation and continuous surface tractions are developed and presented for the membrane (2‐D elasticity) problem. In this case the formulation requires the approximation of three independent variables: two components of a first‐order stress function vector and a scalar rotation. Numerical performance of three quadrilateral dual–mixed elements is presented and compared to displacement‐based hp finite elements when the Poisson ratio converges to the incompressible limit of 0.5. The numerical results show that, as expected, the dual–mixed elements developed in this paper are free from locking in the energy norm as well as in the stress computations, for both h‐ and p‐extensions. Copyright © 2001 John Wiley & Sons, Ltd.