bluuebunny/crossref_metadata_2025 huggingface dataset:
Do firm and state antitakeover provisions affect how well CEOs earn their pay?
Authors: Barnhart Scott W. , Spivey Michael F. , Alexander John C.
Published: August 2002

The relationship between CEO pay‐adjusted firm performance and firm‐specific antitakeover amendments and state antitakeover laws is examined. The findings suggest that the potential entrenchment resulting from the reduced threat of external control provided by antitakeover provisions may allow the CEO to deliver a lower level of firm performance relative to their compensation. At first glance, the state antitakeover provisions appear to be insignificant in the presence of firm‐specific amendments. However, further analysis reveals they can play an important role, in some cases reinforcing the effects of the firm‐specific amendments. With respect to the firm‐specific amendments, the negative relation is associated with the presence of blank check preferred stock and poison pill amendments. Copyright © 2000 John Wiley & Sons, Ltd.
Is essential tremor predominantly a kinetic or a postural tremor? A clinical and electrophysiological study
Authors: Brennan Kevin C. , Jurewicz Eva C. , Ford Blair , Pullman Seth L. , Louis Elan D.
Published: August 2002

Both postural and kinetic tremors may occur in essential tremor (ET), however the relative contribution of each is not clear. ET has been variably defined with respect to kinetic and postural tremors. To examine the relative severity of postural and kinetic tremors in ET, 50 ET cases from a clinic and 55 from a community underwent a videotaped tremor examination. Kinetic and postural tremors were rated using a validated clinical rating scale (score range, 0–3). Thirty‐one cases also underwent accelerometry to precisely quantify tremor amplitude. In clinic cases, the mean postural tremor rating was 1.25 (S.D., 0.89). The mean kinetic tremor rating was 52% higher (1.90; S.D., 0.57; P < 0.001). The community cases had similar characteristics. Sixty percent of the 105 cases had postural tremor ratings scoring 0 or 1 (no tremor or low amplitude, intermittent tremor). In clinic cases, the mean amplitude of postural tremor during tremor analysis was 0.51 mm (S.D., 0.66 mm), and the mean amplitude of kinetic tremor was 2.91 mm (S.D., 2.11 mm; P < 0.01). Similar values were obtained for community cases. These quantitative data suggest that kinetic tremor is more severe than postural tremor in ET. The majority of cases had mild or absent postural tremor. Despite this, ET is defined only as a postural tremor in many studies. Our data argue for a more consistent inclusion of kinetic tremor in diagnostic criteria for ET. © 2002 Movement Disorder Society.
Hemiballism with hyperglycemia and striatal T1‐MRI hyperintensity: An autopsy report
Authors: Ohara S. , Nakagawa S. , Tabata K. , Hashimoto T.
Published: August 2002

We report on an autopsy findings of a 92‐year‐old male with hemiballism‐hemichorea associated with hyperglycemia and striatal hyperintensity on T1‐weighed magnetic resonance imaging (MRI), a recently described clinicoradiological syndrome. Histologically, the putamen contralateral to the hemiballism consisted of multiple foci of recent infarcts associated with reactive astrocytic and interneuronal response. Substrate responsible for the MRI signal changes is still inconclusive. © Movement Disorder Society.
Predictors of depressive symptoms among spouse caregivers in Parkinson's disease
Authors: Fernandez Hubert H. , Tabamo Rowena E.J. , David Raymund R. , Friedman Joseph H.
Published: August 2002

The objective of this work was to determine the predictors of depressive symptoms among spouse caregivers of Parkinson's disease (PD) patients. Little is known about the strain in giving care to PD patients and how the motor, cognitive, and behavioral complications of PD contribute to depression among spouse caregivers.

Forty‐five consecutive PD patients and their spouse caregivers agreed to be evaluated after a routine clinic visit. Patient demographic data and the presence of hallucinations, delusions, incontinence, and sleep disturbances were obtained. The patients were assessed using the Unified Parkinson's Disease Rating Scale (UPDRS‐motor section), Hoehn and Yahr (H&Y) staging, and the Mini‐Mental State Examination (MMSE). Depressive symptoms were assessed using the 17‐item Hamilton Depression Scale (HAMD‐17) and the Beck Depression Inventory‐II (BDI‐II) on patients and spouses.

Thirty men and 15 women had a mean age of 71.5 years (range 53–85), average PD duration of 10 years (range 1–26), a mean “on” H&Y stage of 2.8 and an MMSE mean score of 26 (range 13–30). There was good correlation between the HAMD‐17 and the BDI‐II scores in both patients (r = 0.69, P = 0.001) and spouses (r = 0.66, P < 0.001). A moderate correlation was noted between the spouse HAMD‐17 score and the patient UPDRS‐motor score (r = 0.34; P = 0.02), the age of PD onset (r = 0.33; P = 0.02) and patient HAMD‐17 scores (r= 0.29; P = 0.05). A stronger correlation was noted between spouse HAMD‐17 scores and the years of PD duration (r= 0.43; P = 0.003). There was a significant difference in the mean spouse HAMD‐17 scores among PD patients with sleep disturbances versus those who did not (10.2 vs. 6.4; P = 0.04). However, on stepwise regression analysis, only the duration of PD remained significant (adjusted r = 0.17; P = 0.003). No difference was noted with hallucinations, delusions or incontinence. We concluded that the duration of PD appears to be the strongest predictor of depressive symptoms among spouse‐caregivers in this small cohort. © 2001 Movement Disorder Society.
Neuropsychiatric assessment of Gilles de la Tourette patients: Comparative study with other hyperkinetic and hypokinetic movement disorders
Authors: Kulisevsky Jaime , Litvan Irene , Berthier Marcelo L. , Pascual‐Sedano Berta , Paulsen Jane S. , Cummings Jeffrey L.
Published: August 2002

The role of the basal ganglia in conditions with co‐occurring movement disorders and neuropsychiatric symptoms is not well known. It has been hypothesized that hyperkinesia ‐disinhibited behaviors and hypokinesia‐inhibited behaviors result from an imbalance between the direct and indirect striatal output pathways, and that differential involvement of these pathways could account for the concurrent abnormalities in movement and behavior observed in these disorders.

This study aimed to evaluate whether the pattern and the extent of the neuropsychiatric manifestations of patients with GTS, a hyperkinetic movement disorder of basal ganglia origin, differs from that of patients with other basal ganglia hyperkinetic (e.g., HD) or hypokinetic (e.g., PSP) movement disorders, and to determine whether patients with GTS show a greater frequency of hyperactive behaviors (e.g., agitation, irritability, euphoria, or anxiety) than PSP patients, and are comparable to patients with HD.

The Neuropsychiatric Inventory (NPI), a scale with established validity and reliability, was administered to 26 patients with GTS (mean age, 30.2 ± 2.2 years), and the results were compared with that of 29 patients with HD (mean age, 43.8 ± 2 years) and 34 with PSP (mean ± S.D. age, 66.6 ± 1.2 years).

There was no difference between the groups in the total NPI scores. However, there was a double dissociation in behaviors: patients with hyperkinetic disorders (HD and GTS) exhibited significantly more agitation, irritability, anxiety, euphoria, and hyperkinesia, whereas hypokinetic patients (PSP) exhibited more apathy. Patients with GTS showed greater scores than HD patients in all those scores differentiating HD and GTS from PSP patients (e.g., agitation, irritability, anxiety and euphoria), and were differentiated in a logistic regression analysis from both HD and PSP patients in having significantly more anxiety. We found that patients with GTS manifested predominantly hyperactive behaviors similar but more pronounced than those presented by patients with HD, while those with PSP manifested hypoactive behaviors.

Based on our findings and the proposed models of basal ganglia dysfunction in these disorders, we suggest that the hyperactive behaviors in GTS are comparable to those observed in HD, being both secondary to an excitatory subcortical output through the medial and orbitofrontal cortical circuits, while in PSP the hypoactive behaviors are secondary to hypostimulation of these circuits. Abnormalities of other brain structures (e.g., amygdala, brainstem nuclei) may account for the significantly higher anxiety scores differentiating GTS from HD patients. © 2001 Movement Disorder Society.
A dual‐frequency circularly polarized structure antenna
Authors: Nannini C. , Ribero J. M. , Dauvignac J. Y. , Pichot Ch.
Published: August 2002

A concept of an original compact dual‐band circularly polarized structure antenna is presented. It consists of a dielectric resonator antenna associated with a microstrip one. This antenna has a return‐loss bandwidth superior to 6% for each band, and offers in circular polarization a great axial ratio. Such a structure maybe useful for spatial applications. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 418–420, 2002.
Combining FDTD simulations with measurements of microstrip ring resonators for characterization of low‐ and high‐K dielectrics at microwaves
Authors: Semouchkina Elena , Cao Wenwu , Lanagan Michael , Mittra Raj , Yu Wenhua
Published: August 2002

This paper shows how the dielectric constant of alumina and rutile substrates at microwave frequencies can be accurately determined by fitting the simulated S‐parameter spectra of microstrip ring resonators, generated via the finite‐difference time‐domain (FDTD) method, to experimentally measured data. The proposed method does not require the determination of the effective dielectric constant and the approximate closed‐form expressions to find the true permittivity of the substrate. This is essential for the characterization of high‐K dielectric materials at high frequencies when the closed‐form expressions are invalid. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 21–24, 2001.
2‐D analytical model for current–voltage characteristics and output conductance of AlGaN/GaN MODFET
Authors: Rashmi  , Haldar Subhasis , Gupta R. S.
Published: August 2002

A two‐dimensional analytical model for an AlGaN/GaN MODFET is presented. The model assumes the velocity saturation of electrons in 2‐DEG, which causes current saturation and accurately predicts the output conductance arising from the channel length modulation. The effects of spontaneous and piezoelectric polarization at the AlGaN/GaN heterointerface, the field‐dependent mobility, and the parasitic source/drain resistances have been incorporated in the analysis. A good fit with the experimental data is obtained for an Al0.15Ga0.85N/GaN MODFET, thus proving the validity of our model. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 117–123, 2001.
A study of the four‐path model for scattering from an object above a half space
Authors: Johnson Joel T.
Published: August 2002

A study of scattering from a dielectric object located above a half space is performed to clarify the accuracy of a “four‐path” model which includes single scattering effects only. An iterative method‐of‐moments solution is used for comparison, and both frequency‐ and time‐domain examples are illustrated to clarify the scattering interactions which occur. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 130–134, 2001.
CNS late‐effects after ALL therapy in childhood. Part III: Neuropsychological performance in long‐term survivors of childhood ALL: Impairments of concentration, attention, and memory*†‡
Authors: Langer Thorsten , Martus Peter , Ottensmeier Holger , Hertzberg Holger , Beck Jörn D. , Meier Walburga
Published: August 2002

Purpose

To date, the event free survival (EFS) after treatment of childhood acute lymphoblastic leukemia (ALL) attains 80%. The survivor group is growing steadily. Therefore, the primary purpose of our study is to define the neuropsychological function and to describe which central nervous system (CNS) functions are impaired following the German ALL‐BFM and COALL protocols for CNS‐negative patients.

Patients and Methods

In a cross‐sectional multicenter study 121 subjects, long‐term survivors of childhood ALL in first continuous complete remission were investigated. Seven years ago, the subjects were treated as standard or medium risk patients according to ALL‐BFM 81, ALL‐BFM 83, or COALL 82 protocols, receiving comparable treatments. According to different CNS‐prophylaxes, two subgroups were compared in the study: the non‐cranially irradiated MTX‐group (methotrexate‐group) (n = 38) and the cranially irradiated RT‐group (radiotherapy‐group) (with MTX i.th.) (n = 83). Intellectual and cognitive abilities of these groups were evaluated using standardized psychometric techniques. The Kaufman factors Verbal Comprehension, Perceptual Organisation and Freedom from Distractibility were calculated. Demographical and clinical data collected at the time of the diagnosis were compared between both groups. The different prognoses for patients within both groups were taken into account using a defined risk factor. Analysis of variance was conducted to relate intellectual performance to age, gender, and CNS‐treatment.

Results

The RT‐group exhibited a lower Full Scale IQ than the MTX‐group (101.2 ± 15.9 vs. 109.9 ± 14.9, P = 0.031). Particularly for the Kaufman factor Freedom from Distractibility the RT‐group showed the lower scores (96.9 ± 14.1 vs. 105.5 ± 12.6, P = 0.037). Significant interactions between gender and CNS prophylactic treatment were observed for Full Scale IQ (P = 0.008), Verbal IQ (P = 0.012), Performance IQ (P = 0.024), Verbal Comprehension (P = 0.004), and Perceptual Organisation (P = 0.032).

Conclusions

Cranial irradiation in combination with MTX therapy was associated with deficits in attention, concentration, and the ability of sequencing and processing, measured by the Kaufman factor Freedom from Distractibility. Our results support the strategy of avoiding prophylactic CNS irradiation in low risk patients. Med. Pediatr. Oncol. 2002;38:320–328. © 2002 Wiley‐Liss, Inc.
Perinatal exposure to infection and risk of childhood leukemia
Authors: Naumburg Estelle , Bellocco Rino , Cnattingius Sven , Jonzon Anders , Ekbom Anders
Published: August 2002

Background

A population‐based case‐control study was conducted to investigate the association between childhood leukemia and infectious exposures during pregnancy and early neonatal period.

Procedure

Children born and diagnosed with leukemia between 1973 and 1989 in Sweden (578 lymphatic, 74 myeloid) were selected as cases. One control was randomly selected for each case and individually matched by sex, month, and year of birth. Children with Down's syndrome were excluded. Exposure data were blindly abstracted from antenatal, obstetric, and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression.

Results

A history of maternal infection was not significantly associated with childhood leukemia, OR = 1.25 (95% CI 0.95–1.65). Maternal lower genital tract infection significantly increased the risk of childhood leukemia, OR = 1.78 (95% CI 1.17–2.72), and especially for children over 4 years of age at diagnosis, OR = 2.01 (95% CI 1.12–3.80). Neonatal infection was not associated with the risk of leukemia. The results remained unaltered after adjustment for potential confounders, and separate analyses for myeloid and lymphoid leukemia.

Conclusions

We could document an association between exposure to maternal lower genital tract infection in utero, and a subsequent risk for childhood leukemia, which indicate the importance of an early exposure. Med Pediatr Oncol 2002;38:391–397. © 2002 Wiley‐Liss, Inc.
1H and 13C NMR study of 6‐aryl‐3‐cinchopheny‐1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles
Authors: Liu Xue‐hui , Xu Hao , Fang Yi‐ou , Cui Yu‐xin , Xu Peng‐fei
Published: August 2002

Ten new 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazole derivatives were synthesized and their NMR spectra were analyzed by 1D and 2D NMR techniques (gCOSY, gHMBC, gHMQC). Copyright © 2001 John Wiley & Sons, Ltd.
Characteristics of the cell membrane fluidity, actin fibers, and mitochondrial dysfunctions of frozen‐thawed two‐cell mouse embryos
Authors: Ahn Haek Jun , Sohn In Pyo , Kwon Hyuck Chan , Jo Do Hyun , Park Young Dong , Min Churl K.
Published: August 2002

Physical and chemical alterations caused by the freezing and thawing and their effects on survivals/developments in vitro were investigated. Of a total of 452 two‐cell mouse embryos, the overall survival rate of the frozen‐thawed embryos was 76.1% (344/452). The blastocyst formation of the frozen‐thawed embryos was 32.6% (44/136) compared to 74.5% (117/157) in the fresh embryos (P < 0.05). The total number of cells in a blastocyst also decreased from 96.0 ± 19.0 (n = 26) in the fresh embryos to 42.0 ± 11.34 (n = 30) in the frozen‐thawed embryos (P < 0.05). Fluorescence recovery after photobleaching (FRAP) measurement revealed about 5‐fold decrease in the cell membrane fluidity with a characteristic time constant (τ) of 1.46 ± 0.13 sec (n = 5) in the frozen‐thawed embryos as opposed to 0.28 ± 0.04 sec (n = 5) in the fresh embryos (P < 0.05). The relative amount of H2O2 in an embryo as quantified by the fluorescence intensity of 2′,7′‐dichlorofluorescein (DCF) showed 62.8 ± 23.5 (n = 24) and 34.2 ± 14.5 (n = 20) in the frozen‐thawed embryos and in the fresh embryos, respectively (P < 0.05). The distribution of actin filaments in the frozen‐thawed embryos revealed an uneven distribution, particularly discontinuities at the “actin band,” which contrasted to an even distribution shown in the fresh embryos. Mitochondrial staining by Rhodamine 123 showed that there was no significant difference between the two treatments in the number and in the distribution of viable mitochondria, but a marked aggregation was seen in the arrested embryos. No Annexin V binding was detected in two‐cell or four‐cell embryos while the binding was positive in the arrested embryos. The mitochondrial membrane potential measured by a membrane potential‐sensitive fluorescent probe 5,5′,6,6′‐tetrachloro‐1,1′,3,3′‐tetraethylbenzimidazol‐ carbocyanine iodide (JC‐1) revealed a marked depolarization in the frozen‐thawed embryos. Finally, terminal deoxynucleotidyl transferase (TdT)‐mediated dUTP‐digoxigenin nick end‐labeling (TUNEL) was employed to quantify the DNA fragmentation. In 75.0% cells of blastocysts (n = 24) in the frozen‐thawed embryos, the DNA fragmentation was detected as opposed to 37.0% in the fresh embryos (n = 20) (P < 0.05). Taken together, it is proposed that during the cryopreservation, two‐cell mouse embryos are subjected to physical and chemical alterations, including destruction of the cell membrane integrity, redistribution of actin fibers, mitochondrial depolarizations, and increased reactive oxygen species (ROS) productions, which then may trigger the apoptotic cascade leading to a decrease in the survival rate and in the developmental rate of the embryos. Mol. Reprod. Dev. 61:466–476, 2002. © 2002 Wiley‐Liss, Inc.
Ubiquitin‐dependent sperm quality control mechanism recognizes spermatozoa with DNA defects as revealed by dual ubiquitin‐TUNEL assay
Authors: Sutovsky Peter , Neuber Evelyn , Schatten Gerald
Published: August 2002

Defective mammalian spermatozoa become ubiquitinated during epididymal passage, a mechanism that may mark the abnormal spermatozoa for proteolytic destruction (Sutovsky et al.,2001a: J Cell Sci 114:1665–1675). It is not known how such spermatozoa are recognized by the epididymal ubiquitination pathway and whether there is a selection against certain types of sperm defects. We examined the relationship between sperm ubiqutination, lifelong sperm morphology and sperm DNA defects using a single chanel, ubiquitin‐activated flow cytometric assay, and a dual, ubiquitin‐TUNEL assay. Semen samples from nine service sires of good‐to‐average fertility were screened. A positive correlation was found between sperm ubiquitination and the average frequency of morphological semen abnormalities from field evaluations performed throughout the reproductive life of individual sires. Sample correlation coefficients were r = 0.65 for primary (head and tail) and r = 0.60 for total semen abnormalities in the single channel assay. In a dual assay, we found a high, positive correlation (r = 0.93) between the ubiquitin‐positive sperm and the TUNEL positive sperm. Substantial correlations (r = 0.47–0.64) were observed when the measurements from these two respective assays were compared for individual sires. While anti‐ubiquitin antibodies recognized most of the TUNEL‐positive sperm cells, the TUNEL‐positive spermatozoa represented only a subset (∼20–40%) of all ubiquitin‐positive cells. It appears that the ubiquitin‐dependent sperm quality control, residing in the epididymal epithelium, has the ability to detect spermatozoa with apoptotic or necrotic DNA, while spermatozoa with defects other than DNA fragmentation are also recognized and ubiquitinated.Mol. Reprod. Dev. 61: 406–413, 2002. © 2002 Wiley‐Liss, Inc.
Mitogen activated protein kinase plays a significant role in metaphase II arrest, spindle morphology, and maintenance of maturation promoting factor activity in bovine oocytes
Authors: Gordo Ana Carla , He Chang Li , Smith Sallie , Fissore Rafael A.
Published: August 2002

Mammalian oocytes are arrested at the G2/M transition of the first meiotic division from which, after reaching full size and subsequent to an LH surge, they undergo final maturation. Oocyte maturation, which involves germinal vesicle breakdown, progression through metaphase I (MI), and arrest at MII, is triggered and regulated by the coordinated action of two kinases, maturation promoting factor (MPF) and mitogen activated protein kinase (MAPK). The importance of the role of MPF in mammalian oocyte maturation is well established, while the role of MAPK, although well understood in mouse oocytes, has not been fully elucidated in oocytes of large domestic species, especially bovine oocytes. Here we show that injection of MKP‐1 mRNA, which encodes a dual specificity MAPK phosphatase, into germinal vesicle stage bovine oocytes prevents the activation of MAPK during maturation. Despite the lack of MAPK activity, MKP‐1‐injected oocytes resume and progress through meiosis, although they are unable to arrest at MII stage and, by 22–26‐hour post‐maturation, exhibit decondensed pronucleus‐like chromatin, a clear sign of parthenogenetic activation. MKP‐1‐injected bovine oocytes exhibit normal activation of MPF activity; however, by 18‐hour post‐maturation, MPF activity starts to decline and by 22–26 hr MPF activity is absent. MKP‐1‐injected oocytes also show disorganized MII spindles with poorly aligned chromosomes. In summary, our results demonstrate that in bovine oocytes MAPK activity is required for MII arrest, maintenance of MPF activity, and spindle organization. Mol. Reprod. Dev. 59:106–114, 2001. © 2001 Wiley‐Liss, Inc.
Infection markers and early signs of neonatal encephalopathy in the term infant
Authors: Shalak Lina F. , Perlman Jeffrey M.
Published: August 2002

Recent evidence points to an association between intrauterine infection and cerebral palsy (CP) in the preterm as well as the term infant. The mechanisms that link these two conditions are unclear. Chorioamnionitis is a common clinical problem complicating 5–10% of pregnancies, whereas the incidence of CP attributed to intrapartum asphyxia is rare. Chorioamnionitis may result in brain injury as a result of interruption of placental blood flow (asphyxia), or via fever and/ or the cytokine release associated with infection. This review will attempt to establish the link between perinatal infection and brain damage in term infants. The characteristics of the perinatal inflammatory response, the potential mechanisms of brain injury associated with infection, and the clinical characteristics of neonatal encephalopathy will be discussed. MRDD Research Reviews 2002;8:14–19. © 2002 Wiley‐Liss, Inc.
Why does MTR change with neuronal depolarization?
Authors: Stanisz Greg J. , Yoon Richard S. , Joy Michael L. G. , Henkelman R. Mark
Published: August 2002

T1 and T2 relaxation, and magnetization transfer (MT) of the rat brain were measured during experimentally induced spreading depression (SD). All measured MR parameters changed during SD: T1 relaxation increased by approximately 13%, whereas the T2 increase was substantially larger (88%). MT results showed an MT ratio (MTR) decrease of 9%. The lack of change in the MT exchange rate indicated that the MT processes between water and macromolecular protons are not affected by neuronal depolarization. The observed decrease in MTR was only caused by changes in T1 and T2 relaxation. Magn Reson Med 47:472–475, 2002. © 2002 Wiley‐Liss, Inc.
Localized two‐dimensional shift correlated MR spectroscopy of human brain
Authors: Thomas M. Albert , Yue Kenneth , Binesh Nader , Davanzo Pablo , Kumar Anand , Siegel Benjamin , Frye Mark , Curran John , Lufkin Robert , Martin Paul , Guze Barry
Published: August 2002

A two‐dimensional (2D) chemical shift correlated MR spectroscopic (COSY) sequence integrated into a new volume localization technique (90°–180°–90°) is proposed for whole‐body MR spectroscopy (MRS). Using the product operator formalism, a theoretical calculation of the volume localization as well as the coherence transfer efficiencies in 2D MRS is presented. Phantom model solutions were used to test and optimize the efficiency of the proposed sequence. A combination of different MRI transmit/receive RF coils was used: a head MRI coil and a 3″ surface coil receive combined with a body coil transmit. The J cross‐peaks due to N‐acetyl aspartate (NAA), glutamate/glutamine (Glx), myo‐inositol (mI), creatine (Cr), choline (Ch), aspartate (Asp), γ‐aminobutyrate (GABA), taurine (Tau), glutathione (GSH), threonine (Thr), and macromolecules (MM) were identified. The cross‐peak intensities excited by the proposed 2D sequence were asymmetric with respect to the diagonal peaks. Localized COSY (L‐COSY) spectra of cerebral prefrontal and occipital gray/white matter regions in 15 healthy controls are presented. Magn Reson Med 46:58–67, 2001. © 2001 Wiley‐Liss, Inc.
Measurement of tissue oxygen extraction ratios from venous blood T2: Increased precision and validation of principle
Authors: Golay Xavier , Silvennoinen M. Johanna , Zhou Jinyuan , Clingman Chekesha S. , Kauppinen Risto A. , Pekar James J. , van Zij Peter C.M.
Published: August 2002

It has recently been shown that parenchymal oxygen extraction ratios (OERs) can be quantified using the absolute T2 of venous blood draining from this tissue (Oja et al., J Cereb Blood Flow Metab 1999;19:1289–1295). Here, a modified Carr‐Purcell‐Meiboom‐Gill (CPMG) multiecho experiment was used to increase the efficiency and precision of this approach and to test the applicability of the two‐compartment exchange model for spin‐echo BOLD effects in pure venous blood. Relaxation measurements on bovine blood as a function of CPMG interecho spacing, oxygen saturation, and hematocrit provided the baseline relaxation and susceptibility shift parameters necessary to directly relate OER to T2 of venous blood in vivo. Using an interecho spacing of 25 ms, the results on visual activation studies in eight volunteers showed T2(CPMG) values increasing from 128 ± 9 ms to 174 ± 18 ms upon activation, corresponding to local OER values of 0.38 ± 0.04 and 0.18 ± 0.05 during baseline activity and visual stimulation, respectively. These OER values are in good agreement with literature data on venous oxygenation and numbers determined previously using a single‐echo approach, while the measured T2s are about 20–40 ms longer. Magn Reson Med 46:282–291, 2001. © 2001 Wiley‐Liss, Inc.
Possible pathogenic role of muscle cell dysfunction in motor neuron death in spinal muscular atrophy
Authors: Guettier‐Sigrist Séverine , Hugel Bénédicte , Coupin Gilliane , Freyssinet Jean‐Marie , Poindron Philippe , Warter Jean‐Marie
Published: August 2002

We have previously shown that myofibers formed by fusion of muscle satellite cells from spinal muscular atrophy (SMA) I or II undergo degeneration 1 to 3 weeks after innervation by rat embryonic spinal cord explants, whereas normal myofibers survive for several months. In the “muscle component” of the coculture, the only cells responsible for the degeneration are the SMA muscle satellite cells. Moreover, SMA muscle satellite cells do not fuse as rapidly as do normal muscle satellite cells. To determine whether death of muscle cells precedes that of motor neurons, we studied the origin and kinetics of release of apoptotic microparticles. In SMA cocultures, motor neuron apoptosis occurred before myofiber degeneration becomes visible, indicating that SMA myofibers were unable to sustain survival of motor neurons. In normal cocultures, motor neuron apoptosis occurred 4 days after innervation. However, it did not continue beyond 2 days. These results strengthen the hypothesis that SMA is due to a defect in neurotrophic muscle cell function. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Passive stiffness is increased in soleus muscle of desmin knockout mouse
Authors: Anderson Judith , Li Zhenlin , Goubel Francis
Published: August 2002

The effects of an absence of desmin on passive stiffness of skeletal muscle were analyzed using soleus muscles from desmin knockout mice. Stiffness was evaluated by analyzing the passive tension induced by a ramp‐and‐hold extension test. This test showed that passive resistance to stretch was largely increased for muscles lacking desmin. This study could facilitate interpretation of changes in muscle mechanics observed in humans affected by desmin‐related myopathies. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1090–1092, 2001
Determination of rock mass strength properties by homogenization
Authors: Pouya A. , Ghoreychi M.
Published: August 2002

A method for determining fractured rock mass properties is presented here on the basis of homogenization approach. The rock mass is considered to be a heterogeneous medium composed of intact rock and of fractures. Its constitutive model is studied numerically using finite element method and assimilating the fractures to joint elements (Coste, Comportement Thermo‐Hydro‐Mécanique des massifs rocheux fracturés. Thèse de Doctorat, Ecole Nationale des Ponts et Chaussées, Paris, 1997). The method has been applied to a granite formation in France. Geological data on different families of fractures have been used for the statistical representation of the fractures. A mesh‐generating tool for the medium with high density of fractures has been developed. The mechanical behaviour of the rock mass (elasticity, ultimate strength and hardening law) has been determined assuming linear elasticity and Mohr–Coulomb strength criterion both for the intact rock and the fractures. Evolution of the mechanical strength in different directions has been determined as a function of the mean stress, thanks to various numerical simulations. The mechanical strength appears to be anisotropic due to the preferential orientation of the fractures. The numerical results allowed us to determine an oriented strength criterion for the homogenized rock mass. A 2D constitutive law for the homogenized medium has been deduced from numerical data. A 3D extension of this model is also presented. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of undrained cavity expansion in elasto‐plastic soils with non‐linear elasticity
Authors: Cao Lai Fa , Teh Cee Ing , Chang Ming‐Fang
Published: August 2002

A large strain analysis of undrained expansion of a spherical/cylindrical cavity in a soil modelled as non‐linear elastic modified Cam clay material is presented. The stress–strain response of the soil is assumed to obey non‐linear elasticity until yielding. A power‐law characteristic or a hyperbolic stress–strain curve is used to describe the gradual reduction of soil stiffness with shear strain. It is assumed that, after yielding, the elasto‐plastic behaviour of the soil can be described by the modified Cam clay model. Based on a closed‐form stress–strain response in undrained condition, a numerical solution is obtained with the aid of simple numerical integration technique. The results show that the stresses and the pore pressure in the soil around an expanded cavity are significantly affected by the non‐linear elasticity, especially if the soil is overconsolidated. The difference between large strain and small strain solutions in the elastic zone is not significant. The stresses and the pore pressure at the cavity wall can be expressed as an approximate closed‐form solution. Copyright © 2001 John Wiley & Sons, Ltd.
Two‐stage component test plans for testing the reliability of a series system
Authors: Vellaisamy P. , Sankar S.
Published: August 2002

A system reliability is often evaluated by individual tests of components that constitute the system. These component test plans have advantages over complete system based tests in terms of time and cost. In this paper, we consider the series system with n components, where the lifetime of the i‐th component follows exponential distribution with parameter λi. Assuming test costs for the components are different, we develop an efficient algorithm to design a two‐stage component test plan that satisfies the usual probability requirements on the system reliability and in addition minimizes the maximum expected cost. For the case of prior information in the form of upper bounds on λi's, we use the genetic algorithm to solve the associated optimization problems which are otherwise difficult to solve using mathematical programming techniques. The two‐stage component test plans are cost effective compared to single‐stage plans developed by Rajgopal and Mazumdar. We demonstrate through several numerical examples that our approach has the potential to reduce the overall testing costs significantly. © 2002 John Wiley & Sons, Inc. Naval Research Logistics, 49: 95–116, 2002; DOI 10.1002/nav.1051
A new kind of fictitious play
Authors: Washburn Alan
Published: August 2002

Gass, Zafra, and Qiu (1996) introduce a modified version of fictitious play for matrix games where only the more successful player's strategy is retained. This paper introduces additional modifications that appear to converge faster. © 2001 John Wiley & Sons, Inc.* Naval Research Logistics 48: 270–280, 2001
Tricarboxylic acid cycle of glia in the in vivo human brain
Authors: Blüml S. , Moreno‐Torres A. , Shic F. , Nguy C.‐H. , Ross B. D.
Published: August 2002

In the brain, acetate is exclusively oxidized by glia. To determine the contribution of glial metabolism to the tricarboxylic acid cycle (TCA), 1‐13C‐acetate was infused in six studies in three normal adult subjects and ­one epileptic receiving valproic acid for seizure control. Ten grams of 99% 1‐13C labeled acetate were infused intravenously as a 3.3% w/v solution over 60 min, during which in vivo 13C MR spectra of the brain were acquired. As expected, 13C label rapidly enriched cerebral bicarbonate, glutamate and glutamine C5. The mean rate of acetate oxidation calculated from steady‐state 13C enrichment of bicarbonate in fasted normal subjects was 0.13 ± 0.03 µmol/g/min (n = 4), approximately 20% of the total cerebral TCA cycle rate. Copyright © 2002 John Wiley & Sons, Ltd.
Duct flow with a transverse magnetic field at high Hartmann numbers
Authors: Barrett K. E.
Published: August 2002

Finite element methods can be used for determining the flow in a straight channel under a variety of wall conductivity conditions when a uniform magnetic field is imposed perpendicular to the flow direction. At high Hartmann numbers oscillatory solutions are found unless sufficient points are placed within the Hartmann layers. In some one‐ and two‐dimensional problems it appears that it is adequate to place one or two points within the Hartmann layer to remove the oscillations. Central core values can sometimes be predicted with good accuracy even when the Hartmann layers are not resolved adequately. A nine‐point Gauss point rule has been used to evaluate the stiffness and other matrices for the eight‐node elements. Copyright © 2001 John Wiley & Sons, Ltd.
All‐hexahedral mesh smoothing with a node‐based measure of quality
Authors: Calvo N. A. , Idelsohn S. R.
Published: August 2002

This research work deals with the analysis and test of a normalized‐Jacobian metric used as a measure of the quality of all‐hexahedral meshes. Instead of element qualities, a measure of node quality was chosen. The chosen metric is a bound for deviation from orthogonality of faces and dihedral angles. We outline the main steps and algorithms of a program that is successful in improving the quality of initially invalid meshes to acceptable levels. For node movements, the program relies on a combination of gradient‐driven and simulated annealing techniques. Some examples of the results and speed are also shown. Copyright © 2001 John Wiley & Sons, Ltd.
On non‐linear transformations for accurate numerical evaluation of weakly singular boundary integrals
Authors: Singh Krishna M. , Tanaka Masataka
Published: August 2002

This paper presents a study of the performance of the non‐linear co‐ordinate transformations in the numerical integration of weakly singular boundary integrals. A comparison of the smoothing property, numerical convergence and accuracy of the available non‐linear polynomial transformations is presented for two‐dimensional problems. Effectiveness of generalized transformations valid for any type and location of singularity has been investigated. It is found that weakly singular integrals are more efficiently handled with transformations valid for end‐point singularities by partitioning the element at the singular point. Further, transformations which are excellent for CPV integrals are not as accurate for weakly singular integrals. Connection between the maximum permissible order of polynomial transformations and precision of computations has also been investigated; cubic transformation is seen to be the optimum choice for single precision, and quartic or quintic one, for double precision computations. A new approach which combines the method of singularity subtraction with non‐linear transformation has been proposed. This composite approach is found to be more accurate, efficient and robust than the singularity subtraction method and the non‐linear transformation methods. Copyright © 2001 John Wiley & Sons, Ltd.
Fixed‐lag smoothing and state estimation in dynamic electrical impedance tomography
Authors: Vauhkonen P. J. , Vauhkonen M. , Kaipio J. P.
Published: August 2002

In electrical impedance tomography (EIT), an approximation for the internal resistivity distribution is computed based on the knowledge of the injected currents and measured voltages on the surface of the body. The conventional approach is to inject several different current patterns and use the associated data for the reconstruction of a single distribution. This is an ill‐posed inverse problem. In some applications the resistivity changes may be so fast that the target changes between the injection of the current patterns and thus the data do not correspond to the same target distribution. In these cases traditional reconstruction methods yield severely blurred resistivity estimates. We have earlier proposed to formulate the EIT problem as an augmented system theoretical state estimation problem. The reconstruction problem can then be solved with Kalman filter and Kalman smoother algorithms. In this paper, we use the so‐called fixed‐lag smoother to solve the dynamic EIT reconstruction problem. We show that data storage difficulties that are associated with the previously used fixed‐interval smoother can be avoided using the fixed‐lag smoother. The proposed methods are compared with simulated measurements and real data. Copyright © 2001 John Wiley & Sons, Ltd.
The extended finite element method for rigid particles in Stokes flow
Authors: Wagner G. J. , Moës N. , Liu W. K. , Belytschko T.
Published: August 2002

A new method for the simulation of particulate flows, based on the extended finite element method (X‐FEM), is described. In this method, the particle surfaces need not conform to the finite element boundaries, so that moving particles can be simulated without remeshing. The near field form of the fluid flow about each particle is built into the finite element basis using a partition of unity enrichment, allowing the simple enforcement of boundary conditions and improved accuracy over other methods on a coarse mesh. We present a weak form of the equations of motion useful for the simulation of freely moving particles, and solve example problems for particles with prescribed and unknown velocities. Copyright © 2001 John Wiley & Sons, Ltd.
Alternative time marching process for BEM and FEM viscoelastic analysis
Authors: Mesquita A. D. , Coda H. B. , Venturini W. S.
Published: August 2002

Based on the weighted residual technique, both Finite Element and Boundary Element alternative procedures for viscoelastic analysis are proposed. After imposing the space approximations, applying the kinematical relations for material and strain velocities at the approximation level, the time integration is carried out using appropriate operators. The Kelvin‐Voigt viscoelastic model is implemented in order to validate the idea. The Newmark β time integral scheme is applied to the Finite Element procedure while the Houbolt scheme is applied to the Boundary Elements, allowing the consideration of dynamic analysis in future works. Copyright © 2001 John Wiley & Sons, Ltd.
Stress resultant geometrically exact form of classical shell model and vector‐like parameterization of constrained finite rotations
Authors: Ibrahimbegovic A. , Brank B. , Courtois P.
Published: August 2002

In this work we consider the geometrically exact shell model subjected to finite rotations, making use of rotation vector parameters for handling the corresponding constrained rotation for smooth shells. A modification of such a parameterization which is based on the incremental rotation vector and thus capable of avoiding the singularity problem is also discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Mathematical model of soil freezing and its numerical implementation
Authors: Mikkola M. , Hartikainen J.
Published: August 2002

A mathematical model is presented to predict the evolution of freezing of water‐saturated soil. It is based on the theory mixtures and the principles of continuum mechanics and macroscopic thermodynamics. The numerical solution of the problem is accomplished using an enriched family of interpolation functions. Copyright © 2001 John Wiley & Sons, Ltd.
Changing fish use on Mangaia, southern Cook Islands: resource depression and the prey choice model
Authors: Butler Virginia L.
Published: August 2002

This study applies the prey choice model from foraging theory to explain changing human use of fish during the 700‐year occupation of Tangatatau Rockshelter, Mangaia, southern Cook Islands. The prey choice model suggests that predators will focus initially on high ranked prey, turning to lower ranked prey if abundance of higher ranked prey declines. It is suggested that increasing human population size would have resulted in increases in harvesting pressure and ultimately prey resource depression. To apply the prey choice model to archaeological faunal records and based on previous research, prey ranks are estimated using overall attributes of taxon body size; the larger the taxon, the higher the rank. Two indices, the Marine and Freshwater Fish Index, are developed to estimate the ratio of high to low ranked prey and are calculated for each zone of the rockshelter. Over time, the indices show a decreasing abundance of high ranked prey and increasing abundance of low ranked prey, which supports the view of resource depression. Skeletal elements from two of the high ranked prey, Serranidae and Anguilla sp., are measured to examine taxon‐specific changes in fish body size/age that would indicate direct human exploitation pressure. Evidence for a decline in Serranidae body size over time suggests that some of the decline in prey abundance and encounter rates results from direct harvesting pressure along with behavioural adjustments in the prey. Sample sizes for Anguilla were insufficient for statistical treatment. Environmental and technological factors that might also affect prey abundance and taxonomic representation do not satisfactorily account for the patterns. Overall, the increasing use of lower ranked prey suggests a decline in foraging efficiency, given higher energetic costs associated with their use. The study adds to a growing body of evidence that Polynesians profoundly affected the indigenous biota on islands they colonized. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal control of deterministic epidemics
Authors: Behncke Horst
Published: August 2002

Various deterministic optimal control models for SIR‐epidemics are investigated in this paper. The epidemics are governed by a rather general interaction, which covers most cases studied in the literature. Vaccination, quarantine, screening or health promotion campaigns as forms of control are considered. In all cases one finds a maximum effort control on some initial time interval. In addition, uniqueness and monotonicity properties of these models are studied. The results are also extended to the infinite time‐horizon situation. Copyright © 2000 John Wiley & Sons, Ltd.
Asymmetric hydroformylation of vinyl acetate catalyzed by zeolite‐supported gelatin–Co–Ru complex
Authors: Zhang Xi , Han Bing , Huang Mei‐Yu , Jiang Ying‐Yan
Published: August 2002

Zeolite‐supported gelatin–cobalt–ruthenium complex (zeo–gelatin–Co–Ru) was prepared by a simple method, first the zeolite and gelatin (chiral natural bio‐polymer) were mixed to give zeolite‐supported gelatin (zeo–gelatin), then this was used as a polymer ligand to react with CoCl2·6H2O and RuCl3·H2O to form the complex. This complex has been found to catalyze the asymmetric hydroformylation of vinyl acetate to give (R)‐2‐acetoxy‐propanal in 83.4% product yield and 90.9% optical yield. And this catalyst could be reused several times without any considerable change in the optical yield. Copyright © 2001 John Wiley & Sons, Ltd.
Estimation of free radical‐quenching activity of leaf pigment extracts
Authors: Arnao Marino B. , Cano Antonio , Alcolea Jesús F. , Acosta Manuel
Published: August 2002

The chromogen 2,2′‐azino‐bis‐(3‐ethylbenzthiazoline‐6‐sulphonic acid) radical (ABTS·+) can be directly generated by the enzymatic system formed by hydrogen peroxide and horseradish peroxidase in ethanolic media. The reaction is time‐ and concentration‐dependent, and the ABTS·+ generated shows excellent stability. The method is an adaptation of the decolouration method previously reported (Cano et al. 1998. Phytochem Anal 9:196–202), which was used for estimating anti‐oxidant activity in aqueous media. When the assay described here was used to quantify the anti‐oxidant activity of two anti‐oxidants, Trolox (an analogue of vitamin E) and β‐carotene, the latter had 2.5 times better anti‐oxidant capacity than Trolox at the same concentration. The free radical quenching activity (anti‐oxidant activity) of leaf pigment extracts was measured and related to the the carotenoid contents in leaf extracts of barley, oat and citrus. The possibilities of using this experimental approach to evaluate the status of photoprotective pigments are discussed. Copyright © 2001 John Wiley & Sons, Ltd.