bluuebunny/crossref_metadata_2025 huggingface dataset:
Zr
O
2
film interfaces with Si and SiO2
Authors: Lopez C. M. , Suvorova N. A. , Irene E. A. , Suvorova A. A. , Saunders M.
Published: August 2005

The interface formed by the thermal oxidation of sputter-deposited Zr metal onto Si(100)- and SiO2-coated Si(100) wafers was studied in situ and in real time using spectroscopic ellipsometry (SE) in the 1.5–4.5 photon energy range and mass spectrometry of recoiled ions (MSRI). SE yielded optical properties for the film and interface and MSRI yielded film and interface composition. An optical model was developed and verified using transmission electron microscopy. Interfacial reaction of the ZrO2 was observed for both substrates, with more interaction for Si substrates. Equivalent oxide thicknesses and interface trap levels were determined on capacitors with lower trap levels found on samples with a thicker SiO2 underlayer. In addition to the optical properties for the intermixed interface layer, the optical properties for Zr metal and unreacted ZrO2 are also reported.
Growth mechanism of polycrystalline silicon films from hydrogen-diluted SiCl4 at low temperature
Authors: Lin Xuanying , Lin Kuixun , Huang Chuajun , Yu Yunpeng , Luo Yilin , Yu Chuying , Huang Rui
Published: August 2005

The growth process of polycrystalline silicon films fabricated at 200 °C by radio-frequency glow discharge plasma-enhanced chemical-vapor deposition technique from hydrogen-diluted SiCl4 has been investigated. We analyze the changes of crystallinity and crystalline grain size with the depth from the top surface of the film through studying the depth profiles of the Raman spectra. The results show that the top surface is composed of silicon nanometer crystalline grains and the clustered amorphous silicon. The component of crystalline phase increases with the increase in depth. Moreover, the film crystallization structure depends strongly on the power. On the other hand, it is almost independent of the substrate temperature and the annealing temperature. Comparing with the growth processes of polycrystalline silicon films from hydrogen-diluted SiH4, it is considered that the formation of nanometer size grains occurs in the gas phase reaction process at the initial stage of film growth, while the grain growth is largely governed by the surface reaction process where in the chlorine element plays an important role.
Structural aspects of synthetic zeolite: A comparative assay through positron annihilation and gas adsorption methods
Authors: Dutta D. , Chatterjee S. , Ganguly B. N. , Pillai K. T.
Published: August 2005

Structural arrangement in alumino-silicate compounds (synthetic zeolite species), which encompasses large cavities and channels, have been discussed on the basis of their molecular organization and is further illustrated with the help of micrographs as perceived through transmission electron microscopic studies. The crystallinity aspects and structural defects were investigated through line broadening in x-ray diffraction and the grain sizes through the Debye-Scherrer method. Further, assays of the void size (micro- as well as mesopores) have been performed through positronium annihilation lifetime spectroscopy (PALS) and Brunauer-Emmett-Teller adsorption-desorption isotherm and compared. Despite of some of the limitations of the latter, the final results are in close agreement. The utility of PALS as a microprobe is illustrated through our models. Finally, it has been justified that PALS not only probes the subnanometer micropore sizes efficiently but it also senses the mesopores.
Instantaneous fluxless bonding of Au with Pb–Sn solder in ambient atmosphere
Authors: Lee Teck Kheng , Zhang Sam , Wong Chee Cheong , Tan Ah Chin
Published: August 2005

A fluxless bonding technique has been developed as a method of flip-chip bonding for microelectronic packaging. The fluxless bonding technique can be achieved instantaneously in an ambient environment between metallic stud bumps and predefined molten solder. This paper describes the mechanics of the bonding action and verifies the effectiveness of this bonding method through wetting balance tests and scanning electron microscope and energy dispersive x-ray analysis. This technique has been demonstrated by using a gold stud bump to break the tin oxide layer over molten solder. This allows for a fast, solid liquid interdiffusion between gold (Au) and the fresh molten eutectic lead-tin (Pb–Sn) solder for joint formation during solidification. This bonding method has been successfully tested with 130-μm-pitch flip-chip bond pads on a joint-in-via flex substrate architecture.
Saturation levels of neoclassical tearing modes in International Thermonuclear Experimental Reactor plasmas
Authors: Lütjens Hinrich , Luciani Jean-François
Published: August 2005

For the future ITER tokamak (International Thermonuclear Experimental Reactor) plasmas [R. Aymar et al., Nucl. Fusion 41, 1301 (2001)] a simple and robust theoretical model for the prediction of the dynamics of neoclassical tearing modes (NTM) is a crucial topic. Presently, this theory is incomplete. Using full magnetohydrodynamic simulations, saturated NTM island widths significantly smaller than those predicted by any existing NTM theory are found. Nevertheless, these islands are sufficiently large to potentially alter the plasma confinement. Some reasons for the departure of the simulation results from the theoretical predictions are suggested and issues to be addressed to achieve a quantitative model are indicated.
Alignment and analyses of MnBi∕Bi nanostructures
Authors: Kang K. , Lewis L. H. , Moodenbaugh A. R.
Published: August 2005

A Mn5Bi95 alloy was rapidly solidified into a mixture of nanocrystalline Bi and metastable Bi(Mn). Heating the ribbons to temperature T=525K in a dc magnetic field causes formation and c-axis alignment of low-temperature phase (LTP) MnBi nanorods along the applied field direction. Nanorod alignment increases with increased magnetic field, with a calculated alignment half-angle of 47° for a sample heated to 520K at 50kOe. In situ magnetization changes suggest that nanorod alignment is achieved by rotation of MnBi particles. Particle alignment enables the measurement of the MnBi nanorod spin reorientation temperature of 100K, the same as its bulk counterpart.
Topsoil foraging and phosphorus acquisition efficiency in maize (Zea mays)
Authors: Zhu Jinming , Kaeppler Shawn M. , Lynch Jonathan P.
Published: August 2005

In soybean and common bean, enhanced topsoil foraging permitted by shallow root architectures is advantageous for phosphorus acquisition from stratified soils. The importance of this phenomenon in graminaceous crops, which have different root architecture and morphology from legumes, is unclear. In this study we evaluated the importance of shallow roots for phosphorus acquisition in maize (Zea mays L.). In a field study, maize genotypes with shallower roots had greater growth in low phosphorus soil than deep-rooted genotypes. For physiological analysis, four maize genotypes differing in root shallowness in the field were grown in solid media with stratified phosphorus availability in a controlled environment. Of the four genotypes, one shallow and one deep genotype were also inoculated with arbuscular mycorrhiza (AM). Shallower genotypes had significantly greater growth and phosphorus accumulation compared with deeper genotypes at low phosphorus availability. Mycorrhizal colonisation altered root shallowness under low phosphorus conditions, increasing shallowness substantially in a deep-rooted genotype but slightly decreasing shallowness in a shallow-rooted genotype. Mycorrhizal colonisation increased phosphorus acquisition under low phosphorus availability. Respiration costs of roots and shoots of phosphorus-efficient genotypes were significantly lower under low phosphorus conditions compared with inefficient genotypes. The physiological efficiency of phosphorus acquisition, expressed as root respiration per unit of phosphorus acquisition, was greater in shallow rooted genotypes. Our results demonstrate that genetic variation for root shallowness exists in maize, that phosphorus and AM can modulate root shallowness independently, and that a shallower root system is beneficial for plant performance in maize at low phosphorus availability. We propose that root architectural traits that enhance topsoil foraging are important traits for improved phosphorus acquisition efficiency of annual grain crops such as maize in addition to legumes.
Book Reviews
Authors: Watkinson Anthony
Published: August 2005

Let Them Eat Cake by Tom Angus Author House, Bloomington, IN, USA 2005 ISBN 1‐4208‐1049‐9 (e), 1‐4208‐1048‐0 (sc), £12.99

Books in the Digital Age: The Transformation of Academic and Higher Education Publishing in Britain and the United States by John B. Thompson Polity Press, 2005, ISBN 0 7456 3477 X (hb), £65, 0 7456 3478 8 (pb), £19.99
The caregene study: muscle-specific creatine kinase gene and aerobic power in coronary artery disease
Authors: Defoor Johan , Martens Kevin , Matthijs Gert , Zieliñska Dominika , Schepers Dirk , Philips Tim , Vlietinck Robert , Fagard Robert , Vanhees Luc
Published: August 2005

In 927 biologically unrelated Caucasian patients with coronary artery disease it was investigated whether the NcoI restriction fragment length polymorphism of the muscle-specific creatine kinase (CKMM) gene is associated with aerobic power and with the response to physical training. Physical training significantly ( P<0.001) increased peak oxygen consumption in the GG, AG and AA NcoI genotypes. Covariate-adjusted peak oxygen consumption at baseline, after training and the response to training were not different across CKMM NcoI genotypes.
Analysis of the nearly identical morpholine monooxygenase-encoding mor genes from different Mycobacterium strains and characterization of the specific NADH : ferredoxin oxidoreductase of this cytochrome P450 system
Authors: Sielaff Bernhard , Andreesen Jan R.
Published: August 2005

Cloning and sequencing of themorABCoperon region revealed the genes encoding the three components of a cytochrome P450 monooxygenase, which is required for the degradation of the N-heterocycle morpholine byMycobacteriumsp. strain HE5. The cytochrome P450 (P450mor) and the Fe3S4ferredoxin (Fdmor), encoded bymorAandmorB, respectively, have been characterized previously, whereas no evidence has hitherto been obtained for a specifically morpholine-induced reductase, which would be required to support the activity of the P450morsystem. Analysis of themoroperon has now revealed the genemorC, encoding the ferredoxin reductase of this morpholine monooxygenase. The genesmorA,morBandmorCwere identical to the corresponding genes fromMycobacteriumsp. strain RP1. Almost identicalmorgenes inMycobacterium chlorophenolicumPCP-1, in addition to an inducible cytochrome P450, pointing to horizontal gene transfer, were now identified. No evidence for a circular or linear plasmid was found inMycobacteriumsp. strain HE5. Analysis of the downstream sequences ofmorCrevealed differences in this gene region betweenMycobacteriumsp. strain HE5 andMycobacteriumsp. strain RP1 on the one hand, andM. chlorophenolicumon the other hand, indicating insertions or deletions after recombination. Downstream of themorgenes, the geneorf1′, encoding a putative glutamine synthetase, was identified in all studied strains. The genemorCofMycobacteriumsp. strain HE5 was heterologously expressed. The purified recombinant protein FdRmorwas characterized as a monomeric 44 kDa protein, being a strictly NADH-dependent, FAD-containing reductase. TheKmvalues of FdRmorfor the substrate NADH (37·7±4·1 μM) and the artificial electron acceptors potassium ferricyanide (14·2±1·1 μM) and cytochromec(28·0±3·6 μM) were measured. FdRmorwas shown to interact functionally with its natural redox partner, the Fe3S4protein Fdmor, and with the Fe2S2protein adrenodoxin, albeit with a much lower efficiency, but not with spinach ferredoxin. In contrast, adrenodoxin reductase, the natural redox partner of adrenodoxin, could not use Fdmorin activity assays. These results indicated that FdRmorcan utilize different ferredoxins, but that Fdmorrequires the specific NADH : ferredoxin oxidoreductase FdRmorfrom the P450morsystem for efficient catalytic function.
The property development process
Authors: Fisher Peter
Published: August 2005

Purpose

This paper aims to contribute to the theory of property development as a complex process that involves multiple drivers, stakeholders and contributions from many academic disciplines.

Design/methodology/approach

The paper presents a web‐based model of the property development process consisting of seven defined major elements, each of which is subdivided and linked by functional relationships. The model is applied to three linked case studies drawn from Grainger Town in Newcastle upon Tyne, UK, which involve the conversion or redevelopment of listed buildings in the context of urban regeneration.

Findings

The case studies examined demonstrate the influential roles of many private sector actors and different arms of government. Site characteristics were found to have a bearing on events, as did long‐term trends. These inputs were often independent of economic or property market forces.

Research limitations/implications

The paper relates primarily to commercial development in the UK. The three case studies inevitably present particular circumstances, though they do represent the reuse of existing urban sites, which is highly complex and increasingly the norm.

Practical implications

The findings of this paper should be of practical benefit to anyone involved in property development and of particular interest to organisations whose core business is not development or to anyone engaged in a public‐private development partnership.

Originality/value

This paper presents an original way of conceiving the property development process using a web‐based model. The model may be used to analyse situations where development is strongly influenced by social, political or environmental factors.
Perceived risk and the consumer buying process: internet airline reservations
Authors: Cunningham Lawrence F. , Gerlach James H. , Harper Michael D. , Young Clifford E.
Published: August 2005

Purpose

This research aims to investigate the premise that the use of internet airline reservation systems is perceived to be riskier than traditional airline reservation shopping.

Design/methodology/approach

A survey of 263 respondents investigated perceived risk at various stages of the consumer buying process.

Findings

The results reveal that perceived risk for airline reservation services follows a pattern throughout the consumer buying process. When viewed as a dynamic process, perceived risk for internet airline services shows more radical changes in risk levels than the traditional service. The analyses indicate that performance, physical, social, and financial risk are related to perceived risk at certain stages of the consumer buying process.

Practical implications

A major finding of this study is that there is a risk premium for internet airline reservation services and the risk premium permeates all stages of the consumer buying process. It is further demonstrated that the internet risk premium does affect usage levels; implying that the internet risk premium is consequential and warrants the implementation of risk mitigation strategies.

Originality/value

Unlike previous studies on perceived risk that typically focused on the relationship of perceived risk and information search, this study examines the dynamics of perceived risk throughout the various stages of the consumer buying process.
Exploring the performance effects of key‐supplier collaboration
Authors: Corsten Daniel , Felde Jan
Published: August 2005

Purpose

To examine the conditions under which the proposed benefits of collaboration between a firm and its suppliers will occur.

Design/methodology/approach

This paper examines buyer‐supplier relationships from the point of view of the buying firm. The paper is based on a Swiss sample of OEM‐supplier relationships. The research question is empirically tested employing a sample of 135 Swiss buyer‐supplier relationships and using structured equation modelling as well as multi‐group comparison to test for quasi‐moderation effects. In this paper it is investigated under which condition collaboration with key suppliers is beneficial for buyers. By linking collaboration with key performance measures and contrasting its effects with relational constructs like trust and dependence it is hoped to add to the growing literature on inter‐organizational relationships in supply chain contexts.

Findings

The results demonstrate that supplier collaboration has a positive effect on buyer performance both in terms of innovative capability and financial results. As expected, trust and dependence play an important role in supplier relationships.

Research limitations/implications

This research is based on a single country (Switzerland) multi‐industry study. Generalizability to other industries or countries may be limited.

Practical implications

Supplier relationships need governance modes that balance control and relational elements. Relationship controlling is an important element in building successful supplier relationships. In order to be able to reap the benefits of collaboration for the entire company, the purchasing department needs incentives that support relationship building. Managers leading a purchasing department can learn what structural elements and processes are necessary to obtain optimal benefits from their supply base.

Originality/value

From a manager's viewpoint, this paper will provide additional insight into when and how collaboration can improve financial performance, enhance innovation, and reduce transaction costs..
Pseudospectral element model for free surface viscous flows
Authors: Chern M.J. , Borthwick A.G.L. , Eatock Taylor R.
Published: August 2005

Purpose

The research is directed at development of an efficient and accurate technique for modelling incompressible free surface flows in which viscous effects may not be neglected. The paper describes the methodology, and gives illustrative results for simple geometries.

Design/methodology/approach

The pseudospectral matrix element method of discretisation is selected as the basis for the CFD technique adopted, because of its high spectral accuracy. It is implemented as a means of solving the Navier‐Stokes equations coupled with the modified compressibility method.

Findings

The viscous solver has been validated for the benchmark cases of uniform flow past a cylinder at a Reynolds number of 40, and 2D cavity flows. Results for sloshing of a viscous fluid in a tank have been successfully compared with those from a linearised analytical solution. Application of the method is illustrated by the results for the interaction of an impulsive wave with a surface piercing circular cylinder in a cylindrical tank.

Research limitations/implications

The paper demonstrates the viability of the approach adopted. The limitation of small amplitude waves should be tackled in future work.

Practical implications

The results will have particular significance in the context of validating computations from more complex schemes applicable to arbitrary geometries.

Originality/value

The new methodology and results are of interest to the community of those developing numerical models of flow past marine structures.
The semantic learning organization
Authors: Sicilia Miguel‐Ángel , Lytras Miltiadis D.
Published: August 2005

Purpose

The aim of this paper is introducing the concept of a “semantic learning organization” (SLO) as an extension of the concept of “learning organization” in the technological domain.

Design/methodology/approach

The paper takes existing definitions and conceptualizations of both learning organizations and Semantic Web technology to develop the new concept.

Findings

The main points in which Semantic Web technology can be applied to learning in organizations are identified, and ontological accounts of organizational earning behaviour are pointed out as the main open question to develop the concept of a SLO.

Originality/value

The paper provides a new conceptual framework for Semantic Web applications in organizational learning, which can be used as a roadmap for further research.
Metaphoric boundary objects as co‐ordinating mechanisms in the knowledge sharing of innovation processes
Authors: Koskinen Kaj U.
Published: August 2005

Purpose

In order that knowledge distribution in companies can be efficient and effective, it should take place without boundaries. However, this is not often the reality. People tend to build up their own boundaries, often creating overly technical terminology so that others cannot participate in what they do. In other words, identity hinges on difference. Establishing these identities weakens the existence of real innovative companies and reinforces barriers within and between organisations. The ability of companies to transcend these barriers is partly based on the recognition of boundary objects. This means that the better the companies understand the nature of the existing boundary objects, the better they can take actions that will help to overcome existing barriers. Therefore the goal of the paper is to highlight boundary objects that co‐ordinate knowledge sharing within and between firms' innovation processes.

Design/methodology/approach

There are many different types of boundary objects. The conceptual paper especially addresses the question of what kind of role metaphoric boundary objects play in the knowledge sharing within and between firms' innovation processes. The study is conducted with the help of a literature survey.

Findings

The results of the study suggest that metaphoric boundary objects may play a significant role as a co‐ordinating mechanism in the knowledge sharing of companies' innovation processes.

Originality/value

The relevance of metaphoric boundary objects resides in the fact that with them companies can create the necessary shared understanding behind the framing and resolution of the emerging problem in innovation activities.
Developments in the inhibition of gastric acid secretion
Authors: Mössner J. , Caca K.
Published: August 2005

Understanding the physiology of gastric acid secretion and the pathophysiology of acid‐related diseases (e.g. gastrooesophageal reflux and peptic ulcer) has led to the development of numerous ways to decrease acid exposure. Pharmacologically one can try to neutralize secreted acid by antacids, prevent stimulation of the parietal cell, improve mucosal defences and block the functioning of the proton pump. Proton pump inhibitors (PPIs) inhibit the final step of acid secretion, and are currently the most potent acid inhibitors. Major therapeutic improvement within the PPI class appears unlikely, as agents in this class share similar chemistry, mode of action, and pharmacokinetic profiles. New approaches that block acid secretion are now being developed. Gastrin (CCK2) receptor antagonists and potassium‐competitive acid blockers (P‐CABs) are in clinical development.
Attitudes to Bereavement and Intellectual Disabilities in an Irish Context
Authors: Dodd Philip , McEvoy John , Guerin Suzanne , McGovern Elizabeth , Smith Elaine , Hillery John
Published: August 2005

Background  The influence of grief and bereavement on the lives of people with intellectual disabilities is currently receiving much interest. Many of the long‐standing rituals associated with bereavement are still practised in Ireland, probably more than in many other Western countries. The present authors were interested in studying the experience of bereavement for people with intellectual disabilities in Ireland, and in making international comparisons.

Method  This mixed method study was carried out using two questionnaires. The first was used to study national service and organisational approaches to bereavement. The second questionnaire (based on Murray et al. 2000) was used to study a staff group working in Ireland, assessing staff knowledge and understanding of the grieving process. The results were compared with a UK staff group who were assessed using the same questionnaire (Murray et al. 2000).

Results  Staff and service attitudes were found to be very positive in supporting people with intellectual disabilities who have been bereaved. There is considerable understanding of the needs of bereaved individuals, and there is a high level of support in the participation in grief rituals. When compared with a UK staff group, Irish staffs were more inclined to encourage individuals to take part in bereavement rituals, though they had less actual experience in supporting bereaved people. Only one service had written bereavement guidelines.

Conclusions  There appears to be cultural differences in the experience of bereavement for people with intellectual disabilities. This is important in the context of staff training and policy development in grief and bereavement.
Classification of Epileptic Seizures: A Hospital‐Based Study of 1,250 Patients in a Developing Country
Authors: Senanayake Nimal
Published: August 2005

The 1981 International Classification of Epileptic Seizures (ICES) was used to study the distribution of seizure types in 1,250 patients attending an Epilepsy Clinic in Sri Lanka. Based on seizure symptomatology 94.6% of the cases could be classified, and by adding the routine interictal EEG findings the percentage of classifiable seizures increased to 97%. Partial seizures (73.8% cases) were three times as common as generalized seizures (23.3% cases). Of the partial seizures, simple partial seizures (SPS) accounted for only 0.4% cases, and complex partial seizures (CPS) for 8.8%, whereas partial seizures secondarily generalized (PSGS) accounted for 64.6%. PSGS had simple onset in 12.5% and complex onset in 34.8% of cases. Myoclonic seizures were the commonest of the generalized seizures, accounting for 14.6% of all cases. Tonic‐clonic seizures accounted for 7.4% of cases; absence seizures accounted for only 1.3%. The study showed the 1981 ICES to be relevant and applicable in a clinical setting with limited investigatory facilities. Difficulties encountered with regard to certain subcategories could be overcome with minor modifications which made the classification operative. Routine EEG confirmed the diagnosis in a significant number of cases but changed the diagnosis in only a few, confirming that a good standardized questionnaire is the key instrument for classifying epileptic seizures.
Cingulate Kindling in Senegalese Baboons, Papio papio
Authors: Wada Juhn A. , Tsuchimochi Hirohito
Published: August 2005

Summary: Kindling of the cingulate cortex in the Senegalese baboon Papio papio led to a protracted nonconvulsive seizure state characterized by immobile staring with (anterior cingulate, AC) or without (posterior cingulate, PC) widening of eyelids and neck flexion, followed by postictal visual searching behavior. Despite early bilateral spread of EEG discharges, ictal and interictal patterns remained persistently asymmetric. Secondary generalization was rapid and predictable once contralateral lower facial twitching associated with sustained adversion developed. After the primary site had been kindled, stimulation of the contralateral homotopic posterior cingulate cortex readily produced afterdischarge. However, it remained localized and kindling growth did not occur. The findings suggest that (a) the cingulate cortex can support nonconvulsive seizures; (b) cingulate seizures are accompanied by asymmetric convexity EEG discharges indicating its lateralized onset; (c) further evolution to convulsive seizures after kindling of cingulate cortex requires access to the ipsilateral frontocentral cortex responsible for facial twitching; and (d) the development of focal epileptogenesis at one cingulate site interferes with clinical seizure development at the homotopic contralateral site.
Rational Design of Anticonvulsants: A Quantum Pharmacologic Study of the Ion Channel–Modulating FMRFamide Tetrapeptide as an Endogenous Anticonvulsant
Authors: Dakin K. A. , Weaver D. F.
Published: August 2005

Summary: We applied the computational techniques of quantum pharmacology to examine molecular conformations (shapes and geometries) of the tetrapeptide FMR Famide (L‐Phe‐L‐Met‐L‐Arg‐L‐Phe‐NH2), determining the geometric features necessary for anticonvulsant activity. The rigorous tiered hierarchical approach used molecular mechanics, molecular dynamics, and semiempirical quantum mechanics calculational methods. Low energy conformations showed pertinent conformational information to be considered in the rational design of novel anticonvulsants. The FMRFamide peptide backbone assumes a bent but primary planar geometry. Distinct polar and nonpolar regions are created as the two Phe residues occupy one “face” of the bent conformation, while the Met and Arg residues occupy the opposite face. The aromatic rings point away from each other along the backbone, and this separation is consistent among the low‐energy conformations at ∼11–12 Å. The Met side chain interacts with neither the peptide back bone nor the side chains of other residues. Molecular mechanics and semiempirical quantum mechanics calculations predict limited variation in the orientation of the Arg side chain.
Extracellular Magnesium and Anticonvulsant Effects of Valproate in Young Rat Hippocampus
Authors: Fueta Yukiko , Siniscalchi Antonio , Tancredi Virginia , Avoli Massimo
Published: August 2005

Summary Extracellular field potential recordings were made in CA3 subfield of hippocampal slices from rats aged 11–22 days. In these experiments, we analyzed the effects induced by modifying [Mg2+] in the medium (1 or 2 mM) on (a) 4‐aminopyridine (4‐AP, 50 μM)‐induced synchronous events (including ictal‐ and interictal‐like epileptiform discharges as well as γ‐aminobutyric acid (GABA)‐mediated potentials), and (b) the changes induced by the antiepileptic drug (AED) valproate (VPA 2 mM) on such activities. Changing [Mg2+] from 1 to 2 mM induced age‐dependent effects consisting of reduction in rate of occurrence of ictal‐like discharges at 11–13 days (55% reduction, p <0.005) and 14–16 days (46% reduction, p <0.025) postpartum. At any age, the rate of occurrence and the amplitude of the GABA‐mediated synchronous potentials tended to decrease in 1 mM [Mg2+] Similar effects were noted when changes in [Mg2+] were made during continuous application of the competitive antagonist of the N‐methyl‐D‐aspartate (NMDA) receptor DL‐2‐amino‐5‐phosphonovalerate (APV 50 μM). As previously reported, interictal and ictal discharges were blocked by addition of VPA to medium containing 2 mM [Mg2+] Such an effect was not observed when [Mg2+] was decreased to 1 mM. In 1 mM, but not in 2 mM [Mg2+], VPA increased the amplitude of GABA‐mediated synchronous potentials. Our results indicate that [Mg2+] plays a role in modulating occurrence of 4‐AP‐induced ictal activity and that it can influence the effects of VPA in this in vitro model of epileptogenesis. Because these findings are also observed in the presence of the NMDA receptor antagonist APV, we conclude that they are nof mediated by a mechanism linked to the NMDA receptor‐ionophore.
Reduction of Plasma Alanine Aminotransferase During Vigabatrin Treatment
Authors: Foletti G. B. , Delisle M.‐C. , Bachmann C.
Published: August 2005

Summary: In 9 drug‐resistant patients with partial seizures treated with vigabatrin, Γ‐vinyl GABA (VGB), alanine aminotransaminase (ALAT) activity in plasma was significantly reduced. Comparison of in vitro with in vivo measurements led us to conclude that this reduction is mainly an in vivo phenomenon, perhaps due to crossenzyme inhibition. The assessment of two biological variables linked with ALAT, glucose and alanine levels under fasting conditions, failed to show any significant metabolic alterations. VGB is an effective drug for partial epilepsy. Our observations do not suggest that reduced ALAT activity'is of clinical concern.
Spectral EEG During Short‐Term Discontinuation of Antiepileptic Medication in Partial Epilepsy
Authors: Tuunainen A. , Nousiainen U. , Pilke A. , Mervaala E. , Partanen J. , Riekkinen P.
Published: August 2005

Summary: The effect of short‐term discontinuation of antiepileptic drugs (AEDs) on spectral analysis of EEG background activity (spectral EEG) was studied in patients undergoing preoperative evaluation for epilepsy surgery. We also wished to clarify whether AED discontinuation would provide lateralizing evidence in spectral EEGs of patients with temporal lobe epilepsy (TLE). Spectral EEGs were performed in 15 patients receiving their regular medication regimen and again after a 1‐week period during AED withdrawal. A subgroup of 9 patients who had previously undergone temporal lobectomies (TLE group) was studied separately. In this group, we evaluated the effect of preceding seizures on spectral EEG derived from temporal neocortical areas. In all patients, spectral EEG changes were detected even after a short‐term AED withdrawal. The total amount of absolute delta activity was reduced and occipital peak frequency and relative alpha activity were increased as compared with baseline values. In TLE patients with habitual seizures occurring <20 h before the spectral EEG recording, lateralization was correctly identified by the greater amount of absolute delta activity ipsilateral to the epileptogenic focus. Epileptic seizures are accompanied by subtle focal slowing in spectral EEG for a much longer period than has been assumed. In addition, postictal spectral EEG over the temporal lobes may have lateralizing value. Further studies in larger numbers of patients are needed to evaluate the role of spectral EEG in the preoperative evaluation of patients for temporal lobe surgery.
Effect of Antiepileptic Drugs on Absence‐Like Seizures in the Tremor Rat
Authors: Hanaya R. , Sasa M. , Ujihara H. , Fujita Y. , Amano T. , Matsubayashi H. , Serikawa T. , Uozumi T.
Published: August 2005

Summary: We examined the effects of conventional antiepileptic drugs (AEDs) on absence‐like seizures in homozygous tremor rats (tm/tm) to determine if they corresponded pharmacologically to human absence seizures and absence‐like seizures in spontaneously epileptic rats (SER: zi/zi, tdtm) with both tonic convulsive and absence‐like seizures. Cortical and hippocampal EEG activity was recorded with chronically implanted electrodes. The effects of AEDS on seizures of the tremor rat showed profiles similar to those observed in human absence seizures and also in absence‐like seizures of SER. The absence‐like seizures, associated with paroxysmal bursts of 5–7–Hz spike‐wave complexes, were inhibited by trimethadione (TMO 200 mg/kg intraperitoneally, i.p.), ethosuximide (ESM100 and 200 mg/kg, i.p.), valproate (VPA100 mg/kg, i.p.), and phenobarbital (PB10 and 20 mg/kg, i.p.1. Phenytoin (PHT 20 mg/kg, i.p.) was ineffective. These results are consistent with the conclusion that the tremor rat is a useful model for evaluating new AEDS for human absence seizures.
Asymmetric Hypsarrhythmia: Clinical Electroencephalographic and Radiological Findings
Authors: Drury Ivo , Beydoun Ahmad , Garofalo Elizabeth A. , Henry Thomas R.
Published: August 2005

Summary: Twenty‐six children (16 boys and 10 girls) with hypsarrhythmia and infantile spasms (IS) were studied at the University of Michigan EEG Laboratory in a 4‐year period. Six (2 boys, 4 girls), had asymmetric hypsarrhythmia with a preponderance of both slowing and epileptic form activity over one hemisphere. All 6 had the symptomatic form of IS, 4 with dysplastic conditions, 1 with porencephaly from a cerebral infarct, and 1 with hypoxic‐ischemic encephalopathy. Five children had focal abnormalities on either physical examination or imaging studies. Four had the highest amplitude slowing and most epileptiform activity ipsilateral to the lesion, in 1, it was contralateral. Asymmetric hypsarrhythmia constituted 23% of cases with hypsarrhythmia examined at our EEG laboratory. The significant success in surgical therapy for some children with IS indicates the importance of identifying focal hemispheric abnormalities even if they are not apparent clinically. EEG may suggest focal changes not detected clinically or radiologically.
Stimulus‐Sensitive Seizures in Postanoxic Coma
Authors: Van Cott Anne C. , Blatt Ilan , Brenner Richard P.
Published: August 2005

Summary: Purpose: To describe four patients with stimulus‐sensitive seizures and myoclonus following severe hypoxic‐ischemic injury.

Methods: In 22 months, four adult patients with myoclonus, generalized tonic‐clonic, and clonic seizures following tactile stimulation were identified. EEG and hospital records were reviewed.

Results: EEGs showed bursts of generalized spike and polyspike activity following tactile stimulation associated with the clinical seizures. No cerebral activity was present between the epileptiform bursts. At times, prolonged periods of suppression were recorded. All patients failed to respond to antiepileptic drugs and died.

Conclusions: Stimulus‐sensitive seizures and myoclonus following anoxia are associated with poor clinical outcome. The presence of seizures and myoclonus in conjunction with epileptiform discharges on EEG confirms that post‐anoxic myoclonus is an epileptic state.
Prolonged Nonepileptic Twilight State with Convulsive Manifestations After Febrile Convulsions: A Clinical and Electroencephalographic Study
Authors: Yamamoto Naoki
Published: August 2005

Summary: EEGs were obtained from 14 infants during behavior clinically diagnosed as prolonged febrile seizures. The clinical manifestations during EEG recordings resembled complex partial seizures (CPS) with convulsive manifestations, but the accompanying EEG waveforms were not epileptiform. Rather, two types of slow wave activity occurred: One was continuous diffuse delta (CDD) waves; the other was diffuse rhythmic theta (DRT) waves. I have termed these clinical states “nonepileptic twilight states with convulsive manifestations” (NETC). Because the CDD and DRT activity was similar to childhood arousal responses, I hypothesized that NETC might be a prolonged arousal state with increased muscle tone induced by a preceding febrile convulsion.
“Obtundation Status (Dravet)” Caused by Complex Partial Status Epilepticus in a Patient with Severe Myoclonic Epilepsy in Infancy
Authors: Wakai Shuji , Ikehata Masami , Nihira Hiroshi , Ito Nozomi , Sueoka Hirofumi , Kawamoto Yoshitaka , Hayasaka Hiroyuki , Chiba Shunzo
Published: August 2005

Summary: Purpose: We report a 1‐year 7‐month‐old boy with severe myoclonic epilepsy in infancy (SME) who exhibited complex partial status epilepticus (CPSE), which was confirmed by ictal video‐EEG analysis. This boy first had a hemi‐convulsion in a hot bath at age 3 months. Thereafter, he exhibited both partial and generalized seizures that were extremely intractable. At age 9 months, he had a prolonged episode of impaired consciousness that fit the “obtundation status in SME” defined by Dravet et al.

Methods and Results: Ictal EEG revealed persisting irregular spike‐and‐wave complexes over the left hemisphere, predominantly in the occipitotemporal area, and confirmed CPSE. The EEG abnormalities with decreased level of the consciousness continued ‐6 h after onset of the symptoms even with AED administration.

Conclusions: Because SME features both generalized and focal seizures, both types of nonconvulsive status may be seen in SME. Although Dravet et al. already reported long‐lasting atypical absences in patients with SME as “obtundation status,” we demonstrated CPSE in an infant with SME who exhibited a prolonged stuporous state.
The α2‐Adrenoreceptor Agonist Clonidine Suppresses Seizures, Whereas the α2‐Adrenoreceptor Antagonist Idazoxan Promotes Seizures in Amygdala‐Kindled Kittens: A Comparison of Amygdala and Pontine Microinfusion Effects
Authors: Shouse Margaret N. , Langer James , Bier Michael , Farber Paul R. , Alcalde Oscar , Moghimi Robert , Richkind Melvyn , Szymusiak Ronald
Published: August 2005

Summary: Purpose: We sought to determine whether local, in vivo microinfusion of an α2‐adrenoreceptor agonist and antagonist into either the amygdala or the pons (locus ceruleus, LC) would have contrasting effects on evoked amygdala‐kindled seizure susceptibility.

Methods: The study population consisted of 6 amygdala‐kindled kittens, each undergoing the same protocol, in which the amygdala microinfusion paradigm preceded the pontine microinfusion series. Microinfusions (1 μl) of the α2‐agonist clonidine (CLON) and of the α2‐antagonist idazoxan (IDA) were made over 1 min through cannulas adjacent to stimulating electrodes in the kindled amygdala or through cannulas adjacent to recording electrodes in the ipsilateral LC. Order of administered drugs (CLON vs. IDA) and dosages (n = 3 each) was partly counterbalanced. Focal and convulsive seizure thresholds were evaluated 10–12 min postinfusion and compared to thresholds obtained during two interspersed control control conditions (vehicle control = 1 μl microinfusion of sterile saline; sham control = needle insertion only).

Results: CLON significantly increased focal and generalized seizure thresholds, whereas IDA significantly reduced seizure thresholds when compared to controls. Magnitude of effects was dose dependent and more potent after pontine than amygdala microinfusion.

Conclusions: Our results confirm and extent findings of previous researchers who used unlocalized in vivo manipulations to show that norepinephrine (NE) is a highly antiepileptic agent in the amygdala kindling preparation. With further investigation, the results may ultimately lead to development of microinfusion techniques as an alternative treatment option for limbic epilepsy.
Evaluation of Case Reports of Aplastic Anemia Among Patients Treated with Felbamate
Authors: Kaufman D. W. , Kelly J. P. , Anderson T. , Harmon D. C. , Shapiro S.
Published: August 2005

Summary:Purpose:Felbamate (FBM) is a new antiepileptic drug (AED) that is often effective in seizure disorders refractory to other treatments; its use has been greatly restricted after cases of aplastic anemia were reported. To elucidate the putative association between FBM and aplastic anemia, we made a detailed evaluation of the first 31 reports.

Methods:Hematologic review according to the criteria of the International Agranulocytosis and Aplastic Anemia Study (IAAAS) confirmed 23 cases (74%) as aplastic anemia; FBM was judged to be theonlyplausible cause for three; confounding (mostly by other drugs) was considered possible, but FBM remained the most likely cause for 11; and there was at least one other plausible cause for 9.

Results:Using a denominator from sales data of 110,000 persons exposed and a numerator of the cases for which FBM was considered theonlyplausible cause, we established a lower limit of incidence of 27 cases of aplastic anemia per million users as compared with the general population rate of 2.0 per million per year. With all confirmed cases used as the numerator, the upper limit of incidence was 209 per million. The “most probable” incidence was estimated to be 127 per million.

Conclusions:Intensive, systematic investigation can maximize the utility of case reports for assessing risks of newly released drugs. The present evaluation confirmed an association between FBM and aplastic anemia; however, confounding was significant for most cases and there was a tenfold range in the “best case” and “worst case” incidence estimates among users.
Early‐Childhood Progressive Myoclonus Epilepsy Presenting as Partial Seizures in Dentatorubral‐Pallidoluysian Atrophy
Authors: Hattori Haruo , Higuchi Yoshihisa , Okuno Takehiko , Asato Reinin , Fukumoto Manabu , Kondo Ikuko
Published: August 2005

Summary: Purpose: We explored the characteristics of epileptic seizures of progressive myoclonus epilepsy (PME) in 2 brothers with dentatorubral‐pallidoluysian atrophy (DRPLA).

Methods: We obtained the case history of the siblings and ictal and interictal EEGs. Postmortem examination or demonstration of elongated CAG repeat in the gene for DRPLA was used to confirm the diagnosis.

Results: Two Japanese siblings developed PME characterized by versive or himiclonic seizures with or without secondarily generalized tonic‐clonic convulsions. The elder brother regressed mentally and exhibited increasing spasticity after age 1 year. Myoclonus and seizures developed at age 4 years. The younger brother had shown psychomotor retardation before age 4 years, when he began to deteriorate further neurologically as the elder brother had. He also developed myoclonus and seizures at that age. Seizures in both patients remained partial until their deaths at ages 19 and 15 years, respectively. Ictal EEG verified partial onset of seizure evolving to generalized tonic‐clonic seizure (GTCS). Interictal EEGs showed multifocal paroxysmal discharges with little or no diffuse paroxysms. Postmortem examination or genetic study confirmed the diagnosis of DRPLA.

Conclusions: Seizures of patients with DRPLA may present as partial seizures in children with early‐onset PME.
Community‐Based Study of Lennox‐Gastaut Syndrome
Authors: Heiskala Hannu
Published: August 2005

Summary: Purpose: Before 1986, the spectrum of childhood epilepsies, including Lennox‐Gastaut syndrome (LGS) and Doose syndrome (DS), known collectively as “epilepsia myoclonica astatica”, was believed to represent a single disease. More recently, some investigators have considered these syndromes to be parts of a continuum. To clarify these theories, neurobiologic factors of the syndromes were studied to determine which qualities were shared and which were unique.

Methods: A retrospective (1975–985), community‐based (Helsinki metropolitan area and the province of Uusimaa) study was designed to seek children with features of LGS and DS. It was assumed that recall bias and the selection of documented history would be similar throughout the group. Ranks of increasing pathology were assigned to different seizure types, EEG results, and drug treatments. A similar procedure was applied to epidemiologic data. Spearman rank‐order correlations were calculated to determine which features correlated with LGS and which correlated with less severe epilepsy.

Results: The survey comprised 75 patients with broadly defined LGS. The annual incidence was 2 in 100,000 children aged 0 to 14 years. Prenatal or perinatal abnormalities did not correlate with severity of epilepsy. As compared with the relatively favorable ranks, the severe epilepsy ranks were more often associated with an early onset of epilepsy, an infectious disease at the onset, delayed development before epilepsy, abnormalities in neurologic or neuroradiologic examinations, and a deteriorating course of the condition.

Conclusions: Patients with LGS are more likely than patients with less severe epilepsy to have a younger age at onset of epilepsy, an infection or both, and a deteriorating course of the condition.