bluuebunny/crossref_metadata_2025 huggingface dataset:
On‐line on‐chip post‐column derivatisation reactions for pre‐ionisation of analytes and cluster analysis in gradient µ‐liquid chromatography/electrospray mass spectrometry
Authors: Spikmans Valerie , Lane Stephen J. , Leavens Bill , Manz Andreas , Smith Norman W.
Published: October 2002

A system is presented that demonstrates the principle of on‐line and on‐chip post‐column derivatisation reactions in micro‐high‐performance liquid chromatography (µ‐HPLC) hyphenated to electrospray time‐of‐flight mass spectrometry (ESI‐TOFMS). In this µ‐HPLC‐chip‐MS set‐up, the analytes are separated using gradient µ‐HPLC and subsequently derivatised on‐chip and detected. One of the major limitations of MS detection is its dependency on the degree of ionisation, which is widely variable and compound‐specific. Optimising and controlling the degree of ionisation in a simple manner would allow MS detection to be truly generic. One way of achieving this is by pre‐ionisation of analytes using simple derivatisation procedures that are both rapid and quantitative. Performing this in situ on the system described here overcomes issues of sample handling and efficiency losses when time‐consuming “bench chemistry” is necessary prior to analysis.
 The power of the system is demonstrated by the separation of primary and secondary amines, which are subsequently derivatised with a positively charged phosphonium complex and detected in an enhanced manner. Typically, molecular cations (M+) are detected showing that the ionisation process is dominated by the phosphonium species, leading to more constant ionisation for a variety of compounds. In addition, stable isotopically labelled (12C/13C)‐phosphonium reagent is used for the reactions, allowing for inherent signal/noise (S/N) improvement and automated data processing using cluster analysis. A similar reaction scheme is used for the derivatisation of ketones and aldehydes, also demonstrating dramatic increases in sensitivity, especially with increasing temperature. Minimal loss in chromatographic fidelity in terms of retention times is observed by the introduction of the micromixer chip into the system.
 Optimal flow rates in µ‐HPLC and ESI‐MS are compatible with flow rates for the chip as well as a multitude of in‐line optical detectors including UV and fluorescence. In addition, the micromixer chip can be positioned pre‐column if preferred. The system is robust, easily fully automated and applicable to a wide variety of reactions. The system has a major advantage in its simple robust connection to the “normal scale” outside world. Copyright © 2002 John Wiley & Sons, Ltd.
A Novel Approach to Biological Treatment of Contaminated Water
Authors: Shirazi Fatemeh R.
Published: October 2002

Over the past few years, the focus of our research has been to respond to the recognized needs for novel biological processes that are capable of destroying a wide range of biodegradable pollutants and providing the perfect environment for complex interspecies interactions required for the degradation of environmental contaminants. A new biotechnology process called Biological Permeable Barrier (BPB) was developed to provide high microbial density, stable environmental conditions, and protective measures for microbial activities for in‐situ bioremediation of contaminated groundwater. This patented technology (U.S. Patent 6,337,019) is based on the creation of a structured matrix, or Bio‐beads, that provides the perfect environment for organic‐degrading microorganisms to establish biofilms capable of destroying the contaminants in water with remarkable stability and control. For over 240 days, the viability and performance of the BPB (Bio‐beads) system were shown for biodegradation of a targeted contaminant, 2,4,6‐ trichlorophenol (TCP), under a variety of operating and stress conditions (Razavi‐Shirazi, 1997). Extensive batch experiments were also conducted to obtain necessary data to determine the rate of TCP diffusion into the Bio‐beads, adsorption properties of the Bio‐beads, and substrate‐use rate of the mixed bioculture as free cells and as immobilized cells (Bio‐beads). A simulated model of BPB was also characterized with its porosity, permeability, and compressibility or deformation under typical field conditions. Our extensive research showed that BPB takes advantage of a controlled biotechnology process to overcome the disadvantages and uncertainties associated with conventional biological processes. A summary of our investigation is presented here. © 2002 Wiley Periodicals, Inc.
Assessing the Phytoremediation Potential of Tall Fescue and Sericea Lespedeza for Organic Contaminants in Soil
Authors: Chekol Tesema , Vough Lester R.
Published: October 2002

The phytoremediation potential of using tall fescue (Festuca arundinacea Schreb.)
grass and sericea lespedeza (Lespedeza cuneata [Dum. ‐Cours.])
legume species was assessed using three different groups of organic contaminants in soil. One hundred parts per
million (ppm) each of a nitroaromatic compound (TNT), a polycyclic aromatic hydrocarbon
(Pyrene), and a polychlorinated biphenyl (Aroclor 1248) were used to contaminate the soils.
The experiments were conducted using soils with high and low organic‐matter content. The results
indicate that recoveries of Pyrene and TNT were very low in all treatments in soil with high
organic‐matter content (6.3 percent) compared with recoveries in soil with low
organic‐matter content (2.6 percent). In contrast, recoveries of PCB from soil were not
dependent on the soil's organic‐matter content. Planting both the legume and grass species had
significant effect on the transformations of TNT and PCB in the soil with low organic‐matter content and
did not affect the fate of Pyrene in both soils. The amount of TNT transformed in the four months of plant
growth was 63 percent in the tall fescue and 46 percent in the sericea‐planted soils, compared with only
a 15 percent unaccounted loss in the unplanted control soils. Furthermore, the grass species, with its massive
root system, was significantly better at causing TNT dissipation compared with the legume species, which has
less root vegetative mass. The plant biomass, particularly the shoot weight of the tall fescue grass, was
significantly increased as a result of TNT treatment. Tall fescue and sericea biomass did not appear to have
any significant effect on Pyrene transformation. Planting sericea provided a significantly high level of PCB
transformation in soils with either high or low amounts of organic matter. Tall fescue did not appear to have
any significant effect on PCB transformation. © 2002 Wiley Periodicals, Inc.
Longitudinal changes in macroinvertebrate assemblages in the Meuse River: anthropogenic effects versus natural change
Authors: Usseglio‐Polatera Philippe , Beisel Jean‐Nicolas
Published: October 2002

A collaborative study among three nations (France, Belgium, Netherlands) along the Meuse River developed a consistent approach for collecting and interpreting macroinvertebrate data. Specific mesohabitats were sampled in 16 locations along an 800‐km stretch of this lowland regulated river. The objective was to assess the ‘river health’ using macroinvertebrate communities as indicators of biological and ecological variation in space. The main changes in assemblages were investigated using multimetric and multivariate approaches. The authors examined relationships between faunal variations and both physico‐chemical gradients and man‐made disturbances. We related species traits to faunal changes and habitat characteristics.

Both a gradual shift from a macroinvertebrate assemblage dominated by insects to a community dominated by crustaceans and molluscs and a drastic decrease in biotic index values were observed along the longitudinal gradient. Taxa were distributed according to oxygen, nitrate and ammonium concentrations, pH, conductivity and summer hydraulic conditions. But major faunal differences among sites could not be explained simply by physico‐chemical variables. The trait analysis underlined the role of temporary habitats in structuring the summer macroinvertebrate community of sites of the uppermost French sector, which supported the most diverse community in terms of trait combination. Downstream the macroinvertebrate community exhibited a more simple and less stable functional organization.

We concluded that the Meuse River exhibited both a high biodiversity and a ‘reasonably good’ water quality in the upper reaches. Two transition zones highlighted the influence of a high degree of human impact on stream integrity. Regulation for navigation, ship traffic and heavily polluted effluent discharges influenced instream conditions via multiple processes determining a decline of both habitat stability and diversity. However, the rare occurrence of habitat‐sensitive species in the lower reaches indicated that a partial recovery of communities may be predicted if restoration and protection of disturbed (especially riparian) habitats are fulfilled. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of aquatic mosses on juvenile fish density and habitat use in the regulated River Suldalslågen, western Norway
Authors: Heggenes Jan , Saltveit Svein Jakob
Published: October 2002

Two morphologically distinct moss communities were found in the River Suldalslågen. The liver moss community consists of species which form a dense mat on the bottom, while the river moss (Fontinalis) community forms long tufts. Moss growth has increased since hydropower regulations due to reduced floods and increased winter flows. Increased moss cover affects the bottom structure, as well as intra‐gravel and near‐bottom hydraulics. We studied densities of juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) by electrofishing and habitat selection by direct underwater observation, in areas with natural moss cover compared with areas where mosses were experimentally removed. Areas with dense mats of liver mosses held lower densities of young of year (YoY) and older salmon parr than areas where liver moss had been removed. No differences in densities of YoY salmon were found between areas with and without Fontinalis. For older salmon, parr results were inconclusive. In some samples more and in others fewer fish were found in areas with Fontinalis moss removed. For trout, densities were higher in areas with Fontinalis, while results for liver moss were inconclusive. No major differences were found with regard to microhabitat selection between areas with and without river moss, suggesting that habitat quality in these areas was similar during summer, except with respect to substrate. Salmon held more exposed positions in areas without liver moss, but this is mainly attributed to different habitat availabilities. It is concluded that the relative increase in liver mosses in the River Suldalslågen has a negative impact on juvenile Atlantic salmon fish density. Copyright © 2002 John Wiley & Sons, Ltd.
Recognition of indoor images employing supporting relation between objects
Authors: Yanai Keiji , Deguchi Koichiro
Published: October 2002

In this paper, we describe a new design of a recognition system for a single image of an indoor scene including complex occlusions. In conventional works, the systems could not recognize images of an indoor scene including complex occlusions. Our system can treat them by employing supporting relation between objects. In our system, first, the system estimates the 3D structure of an object by fitting a 3D structure model to the image qualitatively. Next, by checking the supporting relation between objects, it eliminates object candidates that cannot exist and estimates real objects from their parts in the image. Finally, the system recognizes objects that are compatible with each other. We implemented the system as a multi‐agent‐based image understanding system. In this paper, we describe the design of the system and results of experiments. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(11): 14–26, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10142
Shape from contour using adaptive image selection
Authors: Akutsu Takashi , Arakawa Ken‐ichi , Murase Hiroshi
Published: October 2002

The “shape‐from‐contour method” reconstructs the 3D shape of the surface of an object by extracting its contour from each of a series of successive images of the object. This can be realized by using a CCD camera, and is a relatively accurate method of obtaining environmental information. However, to obtain an accurate result, many images must be processed. Therefore, it is important to select the images depending on their effect on the final result, particularly for high‐speed processing.

This paper proposes an adaptive image selection (AISE) method which depends on the required accuracy. The method has been applied to objects having various cross‐sectional shapes. The errors in shape reconstruction and the number of images required in the conventional method and the proposed method are compared. The experimental results show that the proposed method requires fewer images than the conventional method, particularly when the surface curvature of the object has large variation. The theoretical relationship between the accuracy of the reconstructed shape and the number of images required is also derived. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(11): 50–60, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.1163
AES study on the interface diffusion and reaction between Cr layer and Si3N4/Si substrate
Authors: Zhu Yongfa , Wang Li , Yao Wenqing , Cao Lili
Published: October 2002

A Cr layer of thickness 190 nm was successfully deposited on the surface of Si3N4/Si substrate using magnetron sputtering in d.c. mode. Auger electron spectroscopy analysis indicated that the interface diffusion was very weak during the deposition. Annealing treatments in the temperature range 300–760 °C in high vacuum were performed in order to promote interface diffusion and reaction between the Cr layer and the Si3N4/Si substrate. Auger electron spectroscopy results indicated that the interface diffusion and reaction took place between the Cr layer and the Si3N4 layer to form CrNxSiy species at 600 °C and was enhanced with increase in temperature. Simultaneously, Si depleted from Si substrate and diffused gradually into the Cr layer through the Si3N4 layer. After the temperature reached 760 °C, most of the Si3N4 species decomposed and a CrSi layer of ∼210 nm formed, indicating that the annealing temperature was the key step in the interface reaction. Interface diffusion and reaction can be enhanced by increasing the temperature or the annealing time. Copyright © 2002 John Wiley & Sons, Ltd.
In situ interfacial analysis of evaporated potassium on the electroluminescent fluorene–thiophene copolymer
Authors: Ling Q. D. , Li S. , Kang E. T. , Neoh K. G. , Liu B. , Huang Wei
Published: October 2002

X‐ray photoelectron spectroscopy (XPS) was used to investigate the interface formation during in situ thermal evaporation of potassium on thin films of an electroluminescent conjugated polymer: poly[2,7‐(9,9‐dihexylfluorene)‐co‐alt‐2,5‐(decylthiophene)] (PFT). The chemical state and composition of the metal/polymer interfaces were studied as a function of the potassium coverage. Potassium was found to interact extensively with the bulk‐adsorbed oxygen to form a layer of metal oxide at the K/PFT interface. Migration of the bulk‐adsorbed oxygen to the surface occurred in response to the deposition of potassium onto the polymer. The changes in the S 2p lineshape suggested the formation of a thiolate species at low potassium coverages and also a sulphide species at higher metal coverages. The presence of charge transfer from the deposited potassium atoms to the carbon atoms of PFT suggested that the polymer had undergone n‐type doping. The deposited potassium atoms also diffused into the subsurface region of the polymer film. Thus, the interface of K/PFT contained mainly the oxidized metal, metallic potassium and metal–polymer charge transfer complexes. Copyright © 2002 John Wiley & Sons, Ltd.
Influence of ESCA analyser acceptance angle on measured thickness of thin oxide layers
Authors: Nylund Anders
Published: October 2002

A theoretical model that takes the influence of the photoelectron take‐off angle and the acceptance angle of the ESCA analyser on the photoelectron intensity into account is outlined. From a known oxide thickness, theoretical oxide and metal intensities are estimated for take‐off angles ranging from 10° to 90°. The model shows good agreement with experimental values recorded from thin aluminium oxide layers of thickness 15 and 23 Å. The model further shows that the oxide thickness estimated from the intensities is lower than the nominal value for the smallest take‐off angles. This behaviour is more pronounced for the larger acceptance angles and is confirmed by experimental results. To compensate for the influence of the acceptance angle on the calculated oxide thickness, an experimentally determined effective take‐off angle must be introduced at the lowest take‐off angles. The ESCA spectrometer used was a PHI 5500 with acceptance angles of ±2°, ±5° and ±7°. Copyright © 2002 John Wiley & Sons, Ltd.
Surface‐core‐level‐shift photoelectron diffraction of Yb(111) films grown on W(110)
Authors: Dávila M. E. , Molodtsov S. L. , Laubschat C. , Asensio M. C.
Published: October 2002

Quantitative analysis of the surface relaxation of thick Yb(111) films grown on W(110) has been performed by photoelectron diffraction (PED) using high‐energy resolution Yb 4f surface core‐level‐shift photoemission spectra. Scanned PED spectra were measured by recording the intensity variation of the bulk and the surface components of the 4f7/2 and 4f5/2 emissions over a photon energy range 140–260 eV for different experimental geometries. Additionally, angular scans for a fixed photon energy of 150 eV were recorded in the crystal high symmetry directions. Analysis of the data set following a trial‐ and ‐error procedure confirmed that Yb grows epitaxially in an fcc structure, without surface reconstruction. The obtained bulk lattice parameter corresponds to 5.44 Å, which is ∼1% contracted with respect to the natural crystal. From the PED surface components an inward relaxation by 3.6 ± 0.3% of the outermost surface layer of Yb is obtained. Copyright © 2002 John Wiley & Sons, Ltd.
A weighted estimating equation for linear regression with missing covariate data
Authors: Parzen Michael , Lipsitz Stuart R. , Ibrahim Joseph G. , Lipshultz Steven
Published: October 2002

Linear regression is one of the most popular statistical techniques. In linear regression analysis, missing covariate data occur often. A recent approach to analyse such data is a weighted estimating equation. With weighted estimating equations, the contribution to the estimating equation from a complete observation is weighted by the inverse ‘probability of being observed’. In this paper, we propose a weighted estimating equation in which we wrongly assume that the missing covariates are multivariate normal, but still produces consistent estimates as long as the probability of being observed is correctly modelled. In simulations, these weighted estimating equations appear to be highly efficient when compared to the most efficient weighted estimating equation as proposed by Robins et al. and Lipsitz et al. However, these weighted estimating equations, in which we wrongly assume that the missing covariates are multivariate normal, are much less computationally intensive than the weighted estimating equations given by Lipsitz et al. We compare the weighted estimating equations proposed in this paper to the efficient weighted estimating equations via an example and a simulation study. We only consider missing data which are missing at random; non‐ignorably missing data are not addressed in this paper. Copyright © 2002 John Wiley & Sons, Ltd.
Meta‐analysis combining parallel and cross‐over clinical trials. III: The issue of carry‐over
Authors: Curtin François , Elbourne Diana , Altman Douglas G.
Published: October 2002

In meta‐analysis combining results from parallel and cross‐over trials, there is a risk of bias originating from the carry‐over effect in cross‐over trials. When pooling treatment effects estimated from parallel trials and two‐period two‐treatment cross‐over trials, meta‐analytic estimators of treatment effect can be obtained from the combination of parallel trial results either with cross‐over trial results based on data of the first period only or with cross‐over trial results analysed with data from both periods. Taking data from the first cross‐over period protects against carry‐over but gives less efficient treatment estimators and may lead to selection bias. This study evaluates in terms of variance reduction and mean square error the cost of calculating meta‐analysis estimates with data from the first period instead of data from the two cross‐over periods. If the information on cross‐over sequence is available, we recommend performing two combined design meta‐analyses, one using the first cross‐over period data and one based on data from both cross‐over periods. To investigate simultaneously the statistical significance of these two estimators as well as the carry‐over at meta‐analysis level, a method based on a multivariate analysis of the meta‐analytic treatment effect and carry‐over estimates is proposed. Copyright © 2002 John Wiley & Sons, Ltd.
Acquiring knowledge by foreign partners from international joint ventures in a transition economy: learning‐by‐doing and learning myopia
Authors: Tsang Eric W. K.
Published: October 2002

This paper proposes and tests a model of how firms acquire knowledge from their international joint venturing experience. Based on survey responses from 73 Singapore and 89 Hong Kong firms with respect to their joint ventures set up in China, the results indicate that both overseeing effort and management involvement are significant channels of knowledge acquisition. The former channel is more important for firms with a great deal of operational experience in China and for parents of older joint ventures. This finding indicates that firms improve their skills of knowledge acquisition through learning‐by‐doing. Moreover, the strategic importance of the venture concerned, instead of the learning intent of the parent, is the driving force behind the allocation of resources to the two channels. This implies that firms mainly learn through managing their key joint ventures. Since a venture that provides novel and fruitful learning experience may not, and need not, be an operation of great strategic importance, this finding suggests the existence of learning myopia. Copyright © 2002 John Wiley & Sons, Ltd.
Automatic layout of statecharts
Authors: Castello Rodolfo , Mili Rym , Tollis Ioannis G.
Published: October 2002

Graphical notations are widely used for system specification. The usefulness of these notations depends primarily on their readability. Hence, automatic methods are needed to obtain efficient and understandable graphical representations of requirements. In this paper, we present an algorithm that automatically generates layouts of statecharts. We assume that relevant information is stored in a structure that we call a decomposition tree, and we draw the graph that models a statechart in a hierarchical fashion. Our approach excludes diagrams with inter‐level transitions. Copyright © 2001 John Wiley & Sons, Ltd.
Lightweight validation of natural language requirements
Authors: Gervasi Vincenzo , Nuseibeh Bashar
Published: October 2002

In this paper, we report on our experiences of using lightweight formal methods for the partial validation of natural language requirements documents. We describe our approach to checking properties of models obtained by shallow parsing of natural language requirements, and apply it to a case study based on part of a NASA specification of the Node Control Software on the International Space Station. The experience reported supports our position that it is feasible and useful to perform automated analysis of requirements expressed in natural language. Indeed, we identified a number of errors in our case study that were also independently discovered and corrected by NASA's Independent Validation and Verification Facility in a subsequent version of the same document, and others that were not discovered. The paper describes the techniques we used, the errors we found and reflects on the lessons learned. Copyright © 2001 John Wiley & Sons, Ltd.
Instrumenting and tuning dataView—a networked application for navigating through large scientific datasets
Authors: Slottow Joan , Shahriari Ali , Stein Michael , Chen Xiao , Thomas Chris , Ender Philip B.
Published: October 2002

dataView is an application that allows scientists to fly visually through large, regularly‐gridded, time‐varying 3D datasets from their desktop computers. dataView works with data that has been divided into cubes and sub‐cubes (which we call ‘tiles’ and ‘subtiles’), sampled at three levels of detail and written to a terabyte data server built on a PC cluster. dataView is a networked application. The dataView client component that runs on the scientist's computer is used only for user interaction and rendering. The selection of data subtiles for any given scene, and the geometry computation performed on those subtiles to create the virtual world, are performed by dataView components run in parallel on nodes of the PC cluster.

This paper describes how we instrumented and tuned the code for improved performance in a networked environment. We report on how we measured network performance, first by inducing network delay and then by running the dataView client component in Washington DC and the compute components in Los Angeles. We report on the effect that tile size, level of detail, and client CPU speed have on performance. We analyze what happens when the geometry computation is performed in parallel using MPI (Message Passing Interface) vs. in serial, and discuss the effect on performance of adding additional computational nodes. Copyright © 2001 John Wiley & Sons, Ltd.
MOLE: A mobile agent system
Authors: Baumann J. , Hohl F. , Rothermel K. , Strasser M. , Theilmann W.
Published: October 2002

Due to its salient properties, mobile agent technology has received rapidly growing attention over the last few years. Many developments ofmobile agent systems are under way in both academic and industrial environments. MOLE is one of the first mobile agent systems that has been developed in the Java language; the first version came out in 1995. Since then MOLE has been constantly improved, and provides a stable environment for development and usage of mobile agents in the area of distributed applications. Furthermore, it has been used extensively in our research at the University of Stuttgart.

In this paper we describe the system MOLE, some of its unique concepts and their implementation, and the results of our research in the areas of security, transactional support, and control mechanisms. Additionally, we discuss some applications built on MOLE. Copyright © 2002 John Wiley & Sons, Ltd.
An object‐oriented tool for simulating distributed real‐time control systems
Authors: Palopoli Luigi , Lipari Giuseppe , Lamastra Gerardo , Abeni Luca , Bolognini Gabriele , Ancilotti Paolo
Published: October 2002

This paper presents an object‐oriented software tool, called RTSIM, aimed at simulating real‐time embedded controllers. The tool consists of a collection of C++ libraries permitting a separate specification of the functional behaviour of the controller and of the hardware/software architecture to be used for its deployment. In particular, it is possible to provide an accurate modelling of the concurrent architecture of the control tasks and of the run‐time support offered by the operating system for the real‐time scheduling of the shared resources (CPU, memory buffers and network links). In this way, it is possible to compare different scheduling solutions by evaluating their simulated performance directly in the domain of the control application. Moreover, the tool can be utilized to tune up design parameters such as the activation frequencies of the tasks. The application of the tool is shown in a meaningful case study. Copyright © 2002 John Wiley & Sons, Ltd.
Additional transformations for multiple‐level escape statements
Authors: Olsson Ronald A.
Published: October 2002

Earlier work suggests that program transformations can simplify program verification. A given program containing complex language features is transformed into a semantically equivalent program containing only simpler language features. The transformed program is proven using a set of proof rules for only the simpler features. That approach was illustrated by transforming a given program that may contain multiple‐level escape statements within nested loops into an equivalent program that contains no escape statements. This paper gives additional transformations, which map a given program that may contain multiple‐level escape statements to a semantically equivalent program (TP) that contains only single‐level escape statements. The proof of TP uses proof rules for single‐level escape statements, or the earlier transformations further map TP to a program with no escape statements, whose proof uses proof rules for loops without escape statements. This paper also discusses escape statements where the number of levels is determined at run‐time. Copyright © 2002 John Wiley & Sons, Ltd.
Gabaergic modulation of the stress response in frontal cortex and amygdala
Authors: Martijena I.D. , Rodríguez Manzanares P.A. , Lacerra C. , Molina V.A.
Published: October 2002

GABAergic neurotransmission is thought to play an important role in the modulation of the central response to stress. In the present study we evaluate the influence of a brief restraint exposure on GABA‐stimulated chloride influx in diverse brain areas presumed to have a major role in the mediation of emotional behaviors following aversive stimulation. A reduced chloride uptake after stress exposure was only observed in frontal cortex and amygdala. Moreover, rats subjected to such stressor performed an anxiogenic behavior when exposed later to the elevated plus‐maze. A comparable behavior in the elevated plus‐maze was observed between animals that were allowed to chew during the restraint experience and those without any stressful manipulation, suggesting that chewing served as an efficient coping behavioral strategy during such threatening situations. In order to explore if chewing during the restraint experience could suppress the reduction in GABA‐stimulated chloride uptake induced by this stressor, rats were allowed or not to chew during restraint and in both cases GABA‐stimulated chloride influx was assayed in frontal cortex and amygdala. The finding of this experiment showed that restrained rats that have the possibility to chew exhibited a similar GABA‐stimulated chloride uptake in cortical tissue to that shown by control, unstressed rats. Moreover, chewing in response to restraint attenuated the reduction of GABA‐stimulated chloride uptake in amygdala, supporting the notion that chewing is an effective coping response to restraint. These experiments suggest that a reduced GABAergic inhibitory control in these areas could be implicated in the emotional sequelae generated by this uncontrollable stressor and that the suppression of this reduction seems to be associated with the occurrence of coping behavioral response to such fear‐inducing stimulus. Synapse 45:86–94, 2002. © 2002 Wiley‐Liss, Inc.
Reviewing old concepts at the start of a new millenium: Growth restriction, adrenal hypoplasia, and thymomegaly in human anencephaly
Authors: Mazzitelli Nancy , Vauthay Liliana , Grandi Carlos , Fuksman Rosa , Rittler Monica
Published: October 2002

Background

Anencephaly has been associated frequently with intrauterine growth retardation (IUGR), consistently with adrenal hypoplasia, and occasionally with an enlarged thymus. Few studies have analyzed the relationship between gestational age (GA), IUGR, associated anomalies and thymomegaly in anencephaly. The aims of our study were to evaluate this relationship and to highlight the usefulness of anencephaly as a model when investigating immune‐endocrine interactions.

Methods

Fifty‐two anencephalics' autopsies were reviewed retrospectively. Body weight, adrenal, and thymus weights were compared to prenatal, postnatal, and stillborn control values, and between associated and isolated anencephalic cases (presenting with and without other unrelated anomalies). Comparisons of adrenal and thymus weights were done by GA and by body weight. Thymus weight:body weight (TW:BW) ratios were compared to expected values.

Results

Anencephalics' body and adrenal weights were lower than their control values, whereas thymus weights did not differ. Body and thymus weights were twice as high in isolated than in associated anencephaly, whereas adrenal weights did not differ. Anencephalics TW:BW ratios were higher than their control values, higher in cases with IUGR, and higher in isolated rather than associated cases. When distributed by GA, thymus weights in anencephaly increased at a higher‐than‐expected rate.

Conclusions

Our results suggest that adrenal hypoplasia is invariably present in anencephaly, and depending on an underdeveloped pituitary gland, seems to be independent of its etiology. On the contrary, IUGR mainly exists in associated cases and thymus enlargement mainly exists in isolated cases, suggesting a relationship with the underlying cause. Teratology 66:105–114, 2002. © 2002 Wiley‐Liss, Inc.
Aryl hydrocarbon receptor nuclear translocator 2 (ARNT2): Structure, gene mapping, polymorphisms, and candidate evaluation for human orofacial clefts
Authors: Barrow Lon L. , Wines Mary E. , Romitti Paul A. , Holdener Bernadette C. , Murray Jeffrey C.
Published: October 2002

Background

Nonsyndromic orofacial clefts have an estimated incidence of 1/1000 live births. Population genetic and embryologic studies suggest that cleft palate only (CPO) may be a distinct clinical entity from cleft lip with or without cleft palate (CL/P). Both CPO and CL/P are thought to be multifactorial in etiology, with evidence indicating that genetic, environmental, and developmental determinants may all play a role. The ARNT2 gene localizes to a conserved linkage group on mouse chromosome 7 that is syntenic with human chromosome 15q23–25. This chromosomal region was previously identified as a teratogen‐induced clefting susceptibility locus in a genome‐wide scan of AXB and BXA recombinant inbred mice. Arnt2 is expressed in the first branchial arch in mice. The teratogen 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) acts through the aryl hydrocarbon receptor (Ahr) pathway to produce dose‐dependent CPO and thymic wasting in mice exposed in utero. Arnt2 and Ahr proteins dimerize in vitro. TCDD exposure is also associated with orofacial clefting in children of parents involved in agricultural work.

Methods

To determine whether ARNT2 influences human craniofacial development, we identified the human ARNT2 gene and conducted genomic structural analysis. Mutational screening was performed in infants with nonsyndromic CPO or CL/P who were identified by the Iowa Birth Defects Registry.

Results

A common amino acid polymorphism was detected but, no obvious disease‐causing mutations were detected by SSCP analysis. The microsatellite marker, GATA89D04 (D15S823) was identified within intron 11 of the human ARNT2 gene, and linkage disequilibrium of nonsyndromic CPO and CL/P parent‐infant trios was conducted.

Conclusions

No association was demonstrated with CPO (n = 45) and CL/P (n = 37). Teratology 66:85–90, 2002. © 2002 Wiley‐Liss, Inc.
Quality of water types in Ukraine evaluated by WaterTox bioassays
Authors: Arkhipchuk V. V. , Malinovskaya M. V.
Published: October 2002

The quality of river, ground‐, and tap water was analyzed using the basic set of WaterTox bioassays [Daphnia (Daphnia magna), Hydra (Hydra attenuata), and lettuce (Lactuca sativa)] as well as two additional bioassays, onion (Allium cepa) and microalga (Selenastrum gracile). Samples of these waters were also concentrated fivefold using a solid‐phase procedure. The results of the Daphnia and Hydra bioassays showed that the winter and spring concentrated and nonconcentrated samples from the Dnieper and Desna rivers, the main water supply sources for Kiev, were nontoxic. In spring, after concentration, the two river samples brought about the same relative decrease in the lettuce root length (by 35%, p < 0.001), where the Desna River sample considerably reduced (by 79.1%, p < 0.001) the number of microalga cells. Samples of groundwater from countryside wells studied in autumn in several villages of the Kiev region were toxic mainly to Hydra (sublethal effects were found in 11%–78%) and lettuce (the root length decreased 15%–56%). Studies of tap water samples from two of the largest cities of Ukraine, Kiev and Kharkiv, were found to be nontoxic to both plants, lettuce and onion, but showed increased sublethal and lethal effects on both animals, Daphnia and Hydra, as well as a reduced number of microalgae. Different bioassays were sensitive to varying degrees to different water types. This reinforces the necessity of using sets of bioassays in toxicity evaluation. In general, all the tested water samples demonstrated some toxicity. These data suggest that drinking water quality in Ukraine needs improvement. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 250–257, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10044
X‐ray microanalytical detection of iron in pigmentation of oral mucosa.
Authors: Hatton P. V. , Brook I. M. , Swift S.
Published: October 2002

A patient was referred to the Charles Clifford Dental Hospital with a grey metallic pigmentation of the hard palate. Conventional histopathological examination was inconclusive, suggesting the presence of either an ephelis (freckle) of pigmentation resulting from a stainless steel upper denture. Material from the pathological specimen was dewaxed and reembedded in Spurr's resin. Examination in the TEM revealed electron dense deposits in the cytoplasm of macrophages. Energy dispersive X‐ray microanalysis demonstrated that these inclusions contained iron. The results suggested that the iron was in a form similar to haemosiderin and had arisen from the steel denture.
Signalling in cell growth and death: adequate nutrition alone may not be sufficient for ciliates
Authors: Wheatley Denys N. , Christensen Søren T. , Schousboe Peter , Rasmussen Leif
Published: October 2002

The initial inoculum level of Tetrahymena in a chemically defined medium determines whether the cells are capable of exponential growth. Below 750 cells ml−1, the cells fail to go into exponential growth and will die within about 20 hours. By adding certain growth stimulants, death can be postponed and the cells begin to grow after a delay which depends on the intensity of the signal. The implication is that autocrine growth factor expression might be required for cells to grow, and that these stimulants either assist its production or lower the cell threshold to its action. The findings in Tetrahymena are reviewed, and the advantages of having a cell system in which all the components of the medium can be carefully controlled is recognised.
Protein‐free culture of VERO cells: a substrate for replication of human pathogenic viruses
Authors: Cinatl Jindrich , Cinatl Jaroslav , Rabenau Holger , Rapp Jens , Kornhuber Bernhardt , Doerr Hans‐Wilhelm
Published: October 2002

A protein‐free chemically defined medium designated PFEK‐1 was developed for culture of VERO cells on polyvinyl formal (PVF) culture surface without serum or other macromolecular supplements. VERO cells proliferated in PFEK‐1 medium on PVF surface to a similar extent as cells in serum‐supplemented medium without previous adaptation from serum‐containing conditions. The protein‐free culture infected with coxsackievirus B4, herpes simplex virus types 1 and 2, measles virus and poliovirus types 1, 2 and 3 developed viral titers comparable to those found in conventionally grown cells. The results demonstrated that VERO cells in protein‐free culture provide a sensitive substrate for the production of human pathogenic viruses which are not contaminated by serum or other protein factors usually added to a culture medium.
Motility and invasive potency of murine T‐lymphoma cells: effect of microtubule inhibitors.
Authors: Verschueren H. , Dewit J. , De Braekeleer J. , Schirrmacher V. , De Baetselier P.
Published: October 2002

ESb and BW‐O‐Li1 are T‐lymphoma cell lines that form metastases in various organs after injection into syngeneic mice. In vitro, both cell lines invade through a fibroblastic monolayer, but ESb cells do so much slower than BW‐O‐Li1. By the use of Fourier analysis of cell outlines, we can relate this difference in invasiveness to a difference in cell motility: ESb cells do not perform any conspicuous shape change, whereas BW‐O‐Li1 cells are actively protruding and retracting large pseudopodia. However, the low‐motile ESb cells become as motile and deformable as BW‐O‐Li1 cells when they have eventually invaded under a fibroblastic monolayer. This indicates that ESb cells do have inherent capability for shape change. Treatment of ESb cells with the microtubule disrupting agent nocodazole concomitantly increases their shape change intensity, and their invasion rate through fibroblast monolayers. On the contrary, the microtubule stabilizing drug taxol inhibits both motility and invasion of BW‐O‐Li1 cells. Our observations suggest that the microtubule network can repress invasion‐bound motility of lymphoid cells.
Macronuclear DNA demethylation is involved in the encystment process of the ciliate Colpoda inflata.
Authors: Palacios Gemma , Martin‐Gonzalez A. , Gutierrez Juan C.
Published: October 2002

Ciliate encystment is an eukaryotic cell differentiation process which involves a specific gene expression, to form the resting stage. In this study, we investigate, for first time, the DNA methylation pattern changes during encystment in the ciliate Colpoda inflata, and the 5‐azacytidine effect on growing cells and encystment. Results indicate that 5‐methylcytosine is present in macronuclear DNA of this ciliate and the 5‐azacytidine treatment induces encystment in growth conditions. From restriction enzyme digestion and 5‐azacytidine experiments, we conclude that a specific DNA demethylation is probably involved in the encystment gene expression of this ciliate.
Disproportionate numbers of rDNA loci in diploid and polyploid testis nuclei of gerris najas detected by fluorescence in situ hybridization
Authors: Becker T. A. , Nagl W.
Published: October 2002

The replication state of rDNA in testes nuclei undergoing polyploidization by classical‐type endomitosis was investigated in Gerris najas (Heteroptera) by means of fluorescence in situ hybridization. The number of just one rDNA locus per haploid genome was determined by in situ hybridization on meiotic nuclei. Additionally, DNA measurements of spermatids and testes nuclei were performed. Although regular duplication levels of nuclear DNA were found within the limits of the accuracy of the method, these did evidently not apply to the ribosomal genes. The comparison of the number of rDNA signals with the DNA content of 106 testis nuclei revealed drastic variations of the number of rDNA loci between individual nuclei with similar DNA content. Polyploid nuclei of the testis epithelium showed too low numbers of rDNA loci in relation to those expected from the levels of ploidy, while cyst cell nuclei displayed increased numbers of rDNA loci. The results indicate that the ribosomal genes are either underreplicated, or in part eliminated, during the endomitotic cycles of epithelium cell nuclei, but amplified in the cyst cell nuclei, probably already at their diploid stage.
Further characterization of a novel lectin derived from silkworm faeces; specific binding to immunoglobulins, and activation of immunocytes
Authors: Hirayama Etsuko , Ishikawa Naomi , Kim Jeman
Published: October 2002

In previous studies a novel lectin‐like glycoprotein was isolated from silkworm faeces and shown to recognize sugar chains, especially mannose on the cell surface as an epitope, and to cause aggregation of various types of cells in suspension. However, this substance caused detachment and aggregation of only some types of plated cells, such as QM‐RSV cells, which are quail myoblasts transformed with a temperature‐sensitive mutant of Rous sarcoma virus (ts‐RSV) at 35.5 °C, a permissive temperature for RSV. As described here, during studies on the mechanism of cell detachment and aggregation of QM‐RSV cells by this new lectin, some novel biological activities of the lectin were recognized. This lectin was found to bind to immunoglobulins (Ig) specifically at specific amino acid sequences, not via recognition of their molecular conformation. It also recognized the neural cell adhesion molecule (NCAM), which is one of the members of the Ig‐superfamily that have Ig‐like domains. Furthermore, it had a strong mitogenic effect on lymphocytes, and also caused about 3‐fold of phagocytosis by macrophages within 24 hr after its addition.
THROMBIN RECEPTOR AND ENDOGENOUS GROWTH‐RELATED PROTEOLYSIS IN HUMAN FIBROBLASTS
Authors: Borich Suzanne M. , Englebretsen D. , Harding D. R. K. , Scott G. K.
Published: October 2002

We have previously shown that thrombin reverses the growth inhibition caused in human fibroblasts when a cell‐surface proteinase is inhibited. A similar result was obtained with asynthetic thrombin receptor agonist peptide, which mimics the conformational change resulting from receptor cleavage by thrombin. Consideration of the effects of the growth‐related proteinase on intracellular second messengers indicates that cleavage of the thrombin receptor by this endogenous proteinase is not a significant event for normal fibroblast growth in culture. Inhibition of the growth‐related proteinase also fails to block the mitogenic action of bombesin. In conjunction with earlier results, this suggests that the intracellularpoint of action of GRP inhibition may be at, or closely connected with, the receptor‐linked tyrosine kinases, and evidence for inhibition of protein phosphorylation following from GRP inhibition is presented.
Comparison of the responses of three rat intestinal epithelial cell lines to angiotensin II
Authors: Smith Roger D.
Published: October 2002

Like RIE‐1 cells, two of the IEC series of rat intestinal epithelial cell lines were found to express functional angiotensin receptors. As in RIE‐1 cells, treatment of IEC‐6 or IEC‐18 cells with angiotensin II (AII) activated phosphatidylinositol‐4,5‐bisphosphate (PIP2) hydrolysis although (in contrast to RIE‐1 cells) the magnitude of AII‐induced PIP2 hydrolysis was small and not associated with a mitogenic response in either IEC cell line. In terms of their other functional responses to AII (activation of protein kinase C (PKC) and a small elevation of cyclic AMP), IEC‐6 cells are otherwise similar to RIE‐1 cells whereas IEC‐18 cells exhibit some phenotypic differences to the other two cell types. Thus, whereas IEC‐6 and RIE‐1 cells each express the AT1 subtype of angiotensin receptor, the higher affinity receptors on IEC‐18 cells are 'atypical', being insensitive to both AT1‐ and AT2‐specific angiotensin receptor antagonists. Furthermore, in contrast to its effects in IEC‐6 and RIE‐1 cells, AII neither activates PKC nor modulates cyclic AMP levels in IEC‐18 cells. Whereas IEC‐18 cells express the myristoylated alanine‐rich C‐kinase substrate (MARCKS), immunoreactive MARCKS was not detected in IEC‐6 or RIE‐1 cells.