Remaining Part (remaining + part)

Distribution by Scientific Domains


Selected Abstracts


Prefrontal and agranular cingulate projections to the dorsal premotor areas F2 and F7 in the macaque monkey

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003
Giuseppe Luppino
Abstract The superior sector of Brodmann area 6 (dorsal premotor cortex, PMd) of the macaque monkey consists of a rostral and a caudal architectonic area referred to as F7 and F2, respectively. The aim of this study was to define the origin of prefrontal and agranular cingulate afferents to F7 and F2, in the light of functional and hodological evidence showing that these areas do not appear to be functionally homogeneous. Different sectors of F7 and F2 were injected with neural tracers in seven monkeys and the retrograde labelling was qualitatively and quantitatively analysed. The dorsorostral part of F7 (supplementary eye field, F7-SEF) was found to be a target of strong afferents from the frontal eye field (FEF), from the dorsolateral prefrontal regions located dorsally (DLPFd) and ventrally (DLPFv) to the principal sulcus and from cingulate areas 24a, 24b and 24c. In contrast, the remaining part of F7 (F7-non SEF) is only a target of the strong afferents from DLPFd. Finally, the ventrorostral part of F2 (F2vr), but not the F2 sector located around the superior precentral dimple (F2d), receives a minor, but significant, input from DLPFd and a relatively strong input from the cingulate gyrus (areas 24a and 24b) and area 24d. Present data provide strong hodological support in favour of the idea that areas F7 and F2 are formed by two functionally distinct sectors. [source]


The Appreciative System of Urban ICT Policies: An Analysis of Perceptions of Urban Policy Makers

GROWTH AND CHANGE, Issue 2 2004
GALIT COHEN-BLANKSHTAIN
ABSTRACT Information and Communication Technology (ICT) has become an important tool to promote a variety of public goals and policies. In the past years much attention has been given to the expected social benefits from deploying ICTs in different urban fields (transportation, education, public participation in planning, etc.) and to its potential to mitigate various current or emerging urban problems. The growing importance of ICTs in daily life, business activities, and governance prompts the need to consider ICTs more explicitly in urban policies. Alongside the expectation that the private sector will play a major role in the ICT field, the expected benefits from ICTs also encourage urban authorities to formulate proper public ICT policies. Against this background, various intriguing research questions arise. What are the urban policy-makers' expectations about ICTs? And how do they assess the future implications of ICTs for their city? A thorough analysis of these questions will provide a better understanding of the extent to which urban authorities are willing to invest in and to adopt a dedicated ICT policy. This study is focusing on the way urban decision-makers perceive the opportunities of ICT policy. After a sketch of recent development and policy issues, a conceptual model is developed to map out the driving forces of urban ICT policies in cities in Europe. Next, by highlighting the importance of understanding the decision-maker's "black box," three crucial variables are identified within this box. In the remaining part of the paper these three variables will be operationalized by using a large survey comprising more than 200 European cities. By means of statistical multivariate methods (i.e., factor and cluster analysis), the decision-makers were able to be characterized according to the way they perceive their city (the concept of "imaginable city"), their opinion about ICT, and the way they assess the relevance of ICT policies to their city. Next, a solid explanatory framework will be offered by using a log-linear logit analysis to test the relationships between these three aspects. [source]


Fly or die: the role of fat stores in the growth and development of Grey-headed Albatross Diomedea chrysostoma chicks

IBIS, Issue 2 2000
KEITH REID
Chicks of albatrosses, like other Procellariiformes, become independent at a mass similar to their parents but during growth attain a peak mass some 30% or more greater, before losing mass prior to fledging. The current views are that this high peak mass represents chicks storing fat reserves as an energy sink, or as an insurance against periodic food scarcity, or as a Consequence of natural stochastic variation in provisioning rate. We analysed growth and body composition of Grey-headed Albatross Diomedea chrysostoma chicks at Bird Island, South Georgia in 1984 and 1986, two years of very different food availability. In 1984 when overall breeding success was only 28% (the lowest in 20 years and less than halt that in 1986), chicks were significantly smaller in terms of peak mass (by 37%), primary length (by 25%), liver, lung, heart and kidney size (by 18,34%) and fat (by 75,80%) but not significantly different in terms of skeletal (tarsus, culmen, ulna, sternum) or muscle (pectoral, leg) size. Despite these differences, there were some important similarities in the patterns of growth in both years. Up to the attainment of peak mass, most of the growth of organs and of skeletal structures was completed and little fat was deposited. In the remaining part of the chick-rearing period, feather growth and acquisition of fat stores were undertaken. Thus Grey-headed Albatross chicks begin to acquire substantial fat stores only during the later part of the development period; this is contrary to the predictions of any of the existing hypotheses concerning provisioning patterns and the role of fat stores in Procellariiformes. We propose that the deposition of fat in the later stages of chick growth is an adaptation to: (a) ensure against energy demands and/or nutritional stress affecting the quality of flight feathers (many of which are not renewed for up to three years after fledging); and (b) provide an energy reserve for chicks to use in the critical period immediately after independence. [source]


Evaluation of well performance using the coupling of boundary element with finite element methods

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2004
L. Jeannin
Abstract In this paper, we apply an FEM,BEM coupling method in petroleum engineering to evaluate complex wells (or fractures) performance. We use boundary element methods around wells and fractures, and finite elements in the remaining part of the reservoir. Copyright © 2004 John Wiley & Sons, Ltd. [source]


An unconditionally convergent algorithm for the evaluation of the ultimate limit state of RC sections subject to axial force and biaxial bending

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2007
G. Alfano
Abstract We present a numerical procedure, based upon a tangent approach, for evaluating the ultimate limit state (ULS) of reinforced concrete (RC) sections subject to axial force and biaxial bending. The RC sections are assumed to be of arbitrary polygonal shape and degree of connection; furthermore, it is possible to keep fixed a given amount of the total load and to find the ULS associated only with the remaining part which can be increased by means of a load multiplier. The solution procedure adopts two nested iterative schemes which, in turn, update the current value of the tentative ultimate load and the associated strain parameters. In this second scheme an effective integration procedure is used for evaluating in closed form, as explicit functions of the position vectors of the vertices of the section, the domain integrals appearing in the definition of the tangent matrix and of the stress resultants. Under mild hypotheses, which are practically satisfied for all cases of engineering interest, the existence and uniqueness of the ULS load multiplier is ensured and the global convergence of the proposed solution algorithm to such value is proved. An extensive set of numerical tests, carried out for rectangular, L-shaped and multicell sections shows the effectiveness of the proposed solution procedure. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Hybrid LES-RANS modelling: a one-equation SGS model combined with a k,, model for predicting recirculating flows

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 9 2003
L. Davidson
Abstract A hybrid LES-RANS modelling approach is proposed. RANS is used in the near wall regions (y+,60), and the turbulence is modelled with a k,, model. LES is used in the remaining part of the flow, and the SGS turbulence is modelled with a one-equation ksgs model. The same continuity and momentum equations are solved throughout the domain, the only difference being that the turbulent viscosity is taken from the k,, model in the RANS region, and from the one-equation ksgs model in the LES region. The new modelling approach is applied to two incompressible flow test cases. They are fully developed flow in a plane channel and the flow over a 2D-hill in a channel. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Semi-adaptive control of convexly parametrized systems with application to temperature regulation of chemical reactors

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2001
Alexander Fradkov
In this paper, we are interested in the problem of adaptive control of non-linearly parametrized systems. We investigate the viability of defining a stabilizing parameter update law for the case when the plant model is convex on the uncertain parameters. We show that, when the only prior knowledge is convexity, there does not exist an adaptation law,derivable from the standard separable Lyapunov function technique of Parks,applicable for all the state space. Therefore, we propose a semi-adaptive state feedback controller where adaptation takes place only in the region of the state space where convexity can be used to reduce parameter uncertainty. In the remaining part of the state space we freeze the adaptation and switch to a robust controller. This scheme ensures semi-global stability for convexly parametrized non-linear systems with matched uncertainty. The proposed controller is then applied to the problem of temperature regulation of continuous stirred exothermic chemical reactors where reaction heat is convex in the uncertain parameters. Copyright © 2001 John Wiley & Sons, Ltd. [source]


Symplectic molecular dynamics integration using normal mode analysis

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 1 2001
anka Jane
Abstract The split integration symplectic method (SISM) for molecular dynamics (MD) integration using normal mode analysis based on a factorization of the Liouville propagator is presented. This approach is quite distinct from others that use fractional-step methods, owing to the analytical treatment of high-frequency motions. The method involves splitting the total Hamiltonian of the system into a harmonic part and the remaining part. Then the Hamilton equations are solved using a second-order generalized leapfrog integration scheme in which the purely harmonic Hamiltonian (which represents the main contribution of the chemical bonds and angles) is treated analytically, i.e., independent of the step size of integration, by a normal mode analysis that is carried out only once, at the beginning of calculation. The whole integration step combines analytical evolution of the harmonic part of the Hamiltonian with a correction arising from the remaining part. The proposed algorithm requires only one force evaluation per integration step. The algorithm was tested on a simple system of linear chain molecules. Results demonstrate the method makes possible the integration of the MD equations over larger time steps without loss of stability while being economical in computer time. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 84: 2,12, 2001 [source]


Application of robust procedures for estimation of breeding values in multiple-trait random regression test-day model

JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2007
J. Jamrozik
Summary Robust procedures for estimation of breeding values were applied to multiple-trait random regression test-day (TD) model to reduce the influence of outliers on inferences. Robust estimation methods consisted of correcting selected observations (defined as outliers) in the process of solving mixed-model equations in such a way that ,new' observations gave residuals (actual observation minus predicted) within k residual standard deviations for a given day in milk in 305-day lactation. Data were 980 503 TD records on 63 346 Canadian Jersey cows. Milk, fat, protein and somatic cell score in the first three lactations were analysed jointly in the model that included fixed herd-TD effect and regressions within region,age,season of calving, and regressions with random coefficients for animal genetic and permanent environmental effects. All regressions were orthogonal polynomials of order 4. Robust procedures for k = 1.5, 2.0, 2.5, 2.75 and 3.0 were contrasted with the regular best linear unbiased prediction (BLUP) method in terms of numbers and distributions of outliers, and estimated breeding values (EBV) of animals. Distributions of outliers were similar across traits and lactations. Early days in milk (from 5 to 15) were associated with larger frequency of outliers compared with the remaining part of lactation. Several, computationally simple, robust methods (for k > 2.0) reduced the influence of outlier observations in the model and improved the overall model performance. Differences in rankings of animals from robust evaluations were small compared with the regular BLUP method. No clear associations between changes in EBV (rankings) of top animals from different methods and the occurrence of outliers were detected. [source]


Effect of a chemical synthesis-based pharmaceutical wastewater on performance, acetoclastic methanogenic activity and microbial population in an upflow anaerobic filter

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002
B Kasapgil Ince
Abstract The performance of an upflow anaerobic filter (UAF) treating a chemical synthesis-based pharmaceutical wastewater was evaluated under various operating conditions. During start-up, the UAF was initially fed by glucose till an organic loading rate (OLR) of approximately 7.5,kg COD m,3 day,1 with a hydraulic retention time of 2.3 days. A soluble COD removal efficiency of 98% was achieved before the addition of the wastewater. Initially, the filter inertia was acclimatized to the wastewater by sequential feeding of 10% (w/v), 30% (w/v) and 70% (w/v) of the pre-aerated wastewater mixed with glucose followed by a 100% (w/v) pre-aerated wastewater. During the operation, the COD removal efficiency and methane yield decreased to 75% and 0.30,m3 CH4,kg,1 CODremoved respectively. As the UAF became accustomed to the pre-aerated wastewater, raw wastewater was fed in increasing ratios of 20% (w/v), 60% (w/v) and 80% (w/v) with the pre-aerated wastewater as the remaining part. During this stage of the operation, a COD removal efficiency in a range of 77,86% was achieved and the methane yield decreased to 0.24,m3 CH4,kg,1 CODremoved. Finally, 100% (w/v) raw wastewater was fed and a COD removal efficiency of 65% was achieved with a methane yield of 0.20,m3 CH4,kg,1 CODremoved. At the end of the operation, acetoclastic methanogenic activity was only measured in the bottom section of the UAF, this showed a 90% reduction in comparison with activity of inoculation sludge. Microscopic examinations revealed that rod-shaped methanogens remained as the dominant species whereas Methanosarcina -like species and filaments were present only in insignificant numbers along the UAF. © 2002 Society of Chemical Industry [source]


Looking for a contribution of the non-equilibrium solvent polarization to the activation barrier of the SN2 reaction

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 6 2002
Jan S. Jaworski
Abstract The solvent effect on the activation free energy of the Finkelstein reaction between methyl iodide and Cl, ions was analysed in terms of the recent Marcus theory unifying the SN2 and the electron transfer reactions. The homolytic bond dissociation energy and the related resonance energy of interaction of the states seem to be almost solvent independent. The sum of the work term wr and the solvent reorganization energy ,0/4 depends strongly on the solvent acidity parameter, e.g. ETN, describing the solvation/desolvation of anions. However, after removing the contribution of the specific solvation the linear increase of the remaining part of ,0/4 with the Pekar factor, describing the non-equilibrium solvent polarization, was observed for six aprotic solvents. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Conclusions and Recommendations for Policies on Rural Aging in the First Decades of the 21st Century

THE JOURNAL OF RURAL HEALTH, Issue 4 2001
Hana M. Hermanova M.D., Ph.D.
ABSTRACT: The 2000 Forum on Rural Aging: Policy Debates was one of the main tracks of the first International Conference on Rural Aging held in Charleston, W.Va., in June 2000. The 2000 Forum was a follow-up to the Expert Group Meeting on Rural Aging, which met at Shepherdstown, W.Va., in May 1999. That group considered policy implications of the 1999 International Year of Older Persons for rural aging in four key areas: the situation of older people, multigenerational relationships, lifelong development, and the development and aging of rural populations. As a direct follow-up of the Shepherdstown Expert Group Meeting, the 2000 Forum on Rural Aging formulated the Conclusions and Recommendations for Policies on Rural Aging through a series of working groups. The Conclusions and Recommendations were endorsed by the Conference Plenary Session on June 11, 2000. The Draft Recommendations for Policies on Rural Aging were available for comments on the Internet in the remaining part of the year 2000. Many comments were received. Hana Hermanova and Sally Richardson incorporated the comments into the finalized version. [source]


Monitoring structural transformations in crystals.

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2006

Structural changes taking place in a crystal during an intramolecular photochemical reaction [the Yang photocyclization of the ,-methylbenzylamine salt with 1-(4-carboxybenzoyl)-1-methyladamantane] were monitored step-by-step using X-ray structure analysis. This is the first example of such a study carried out for an intramolecular photochemical reaction. During the photoreaction, both the reactant and product molecules change their orientation, but the reactant changes more rapidly after the reaction is about 80% complete. The distance between directly reacting atoms in the reactant molecule is almost constant until about 80% reaction progress and afterwards decreases. The torsion angle defined by the reactant atoms that form the cyclobutane ring also changes in the final stages of the photoreaction. These phenomena are explained in terms of the influence of many product molecules upon a small number of reacting molecules. The adamantane portion shifts more than the remaining part of the anionic reactant species during the reaction, which is explained in terms of hydrogen bonding. The structural changes are accompanied by changes in the cell constants. The results obtained in the present study are compared with analogous results published for intermolecular reactions. [source]


Candidate Gene Association Study for Noise-induced Hearing Loss in Two Independent Noise-exposed Populations

ANNALS OF HUMAN GENETICS, Issue 2 2009
A. Konings
Summary Millions of people are daily exposed to high levels of noise. Consequently, noise-induced hearing loss (NIHL) is one of the most important occupational health hazards worldwide. In this study, we performed an association study for NIHL based on a candidate gene approach. 644 Single Nucleotide Polymorphisms (SNPs) in 53 candidate genes were analyzed in two independent NIHL sample sets, a Swedish set and part of a Polish set. Eight SNPs with promising results were selected and analysed in the remaining part of the Polish samples. One SNP in PCDH15 (rs7095441), resulted in significant associations in both sample sets while two SNPs in MYH14 (rs667907 and rs588035), resulted in significant associations in the Polish sample set and significant interactions with noise exposure level in the Swedish sample set. Calculation of odds ratios revealed a significant association of rs588035 with NIHL in the Swedish high noise exposure level group. Our studies suggest that PCDH15 and MYH14 may be NIHL susceptibility genes, but further replication in independent sample sets is mandatory. [source]


Contribution of Nitric Oxide Synthase to Improved Early Graft Patency in Human Saphenous Vein Graft Harvested by a Novel ,No-Touch' Technique

JOURNAL OF CARDIAC SURGERY, Issue 6 2002
JCS Tsui
Aim: Saphenous vein (SV) is the most commonly used conduit in bypass procedures but has a one-year occlusion rate of 15-30%. A new ,no-touch' technique where the SV is harvested with a cushion of surrounding tissue with no distension has led to improved early patency rates of 5% at 18-months. Nitric oxide (NO), synthesised by nitric oxide synthase (NOS) has properties beneficial to graft patency. Our aim was to study the distribution of NOS in SV harvested by this technique and the effect of distension and removal of perivascular tissue on NOS content of SV. Methods: Following ethical committee approval and patients' informed consent, SVs were harvested from ten patients undergoing coronary artery bypass grafting. A segment of vein was harvested by the conventional technique (surrounding tissue stripped and vein distended with saline); another part was stripped but not distended (,control') and the remaining parts harvested by the ,no-touch' technique. Samples of each segment were taken and transverse sections prepared for NOS identification using 3[H]L-NG nitroarginine (NO Arg) autoradiography and NADPH-diaphorase histochemistry. NOS isoforms were studied using standard immunohistochemistry. Endothelial cells and nerves were also identified using immunohistochemistry with CD31 and NF200 respecitvely, to confirm sources of NOS. Morphometric analysis of NADPH-diaphorase staining was carried out to study tissue NOS content. Results: NO Arg binding representing NOS was preserved on the lumen of ,no-touch' vessels whilst that on conventional and control vessels was reduced. NOS was also localised to the medial smooth muscle cells of all vein segments and to the intact adventitia of ,no-touch' segments. This was confirmed by NADPH-diaphorase staining, which revealed a mean reduction of NOS by 19.5% (p < 0.05, ANOVA) in control segments due to stripping of surrounding tissue alone and a reduction of 35.5% (p < 0.01, AVNOVA) in conventional segments due to stripping and distension, compared to ,no-touch' segments. Adventitial NOS sources in ,no-touch' vessels corresponded to vasa vasorum and paravascular nerves. All three NOS isoforms contributed to the preserved NOS in ,no-touch' vessels. Conclusions: Apart from preserved lumenal NOS, NOS sources are also located in the media and adventitia of SV grafts. These are reduced by both adventitial damage and vein distension during conventional vein harvesting. The ,no-touch' technique avoids these procedures, preserving NOS sources. This may result in improved NO availability in SV harvested by this technique, contributing to the improved patency rates reported. [source]


Tension and stress in the rat and rabbit stomach are location- and direction-dependent

NEUROGASTROENTEROLOGY & MOTILITY, Issue 3 2005
J. Zhao
Abstract, Distension studies in the stomach are very common. It is assumed in pressure,volume (barostat) studies of tone and tension in the gastric fundus that the fundus is a sphere, i.e. that the tension in all directions is identical. However, the complex geometry of the stomach indicates a more complex mechanical behaviour. The aim of this study was to determine uniaxial stress,strain properties of gastric strips obtained from rats (n = 12) and rabbits (n = 10). Furthermore, we aimed to study the gastric zero-stress state since the stomach is one of the remaining parts of the gastrointestinal tract where residual strain studies have not been conducted. Longitudinal strips (in parallel with the lesser curvature) and circumferential strips (perpendicular to the lesser curvature) were cut from the gastric fundus (glandular part) and forestomach (non-glandular part). The residual stress was evaluated as bending angles (unit: degree per unit length and negative when bending outwards). The residual strain was computed from the change in length between the zero-stress state and no-load state. The stress,strain test was performed using a tensile test machine. The thickness and width of each strip were measured from digital images. The strips data were compared with data obtained in the intact stomach in vitro. Most residual stresses and strains were bigger in the glandular part than in the forestomach, and in general the rat stomach had higher values than the rabbit stomach. The glandular strips were stiffer than the forestomach strips and the longitudinal glandular strips were stiffer than the circumferential glandular strips (P < 0.05). The gastric strips were stiffer in rats than in rabbits (P < 0.01). The data obtained in the intact rat stomach confirmed the strips data and indicated that those were obtained in the physiological range. In conclusion, the biomechanical properties of the gastric strips from the rat and rabbit are location-dependent, direction-dependent and species-dependent. The assumption in physiological pressure,volume studies that the stomach is a sphere with uniform tension is not valid. Three-dimensional geometric data obtained using imaging technology and mechanical data are needed for evaluation of the stomach function. [source]


Coupling 3D and 1D fluid-structure interaction models for blood flow simulations

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2006
L. Formaggia
Three-dimensional (3D) simulations of blood flow in medium to large vessels are now a common practice. These models consist of the 3D Navier-Stokes equations for incompressible Newtonian fluids coupled with a model for the vessel wall structure. However, it is still computationally unaffordable to simulate very large sections, let alone the whole, of the human circulatory system with fully 3D fluid-structure interaction models. Thus truncated 3D regions have to be considered. Reduced models, one-dimensional (1D) or zero-dimensional (0D), can be used to approximate the remaining parts of the cardiovascular system at a low computational cost. These models have a lower level of accuracy, since they describe the evolution of averaged quantities, nevertheless they provide useful information which can be fed to the more complex model. More precisely, the 1D models describe the wave propagation nature of blood flow and coupled with the 3D models can act also as absorbing boundary conditions. We consider in this work the coupling of a 3D fluid-structure interaction model with a 1D hyperbolic model. We study the stability of the coupling and present some numerical results. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Contributions of folding cores to the thermostabilities of two ribonucleases H

PROTEIN SCIENCE, Issue 2 2002
Srebrenka Robic
Abstract To investigate the contribution of the folding cores to the thermodynamic stability of RNases H, we used rational design to create two chimeras composed of parts of a thermophilic and a mesophilic RNase H. Each chimera combines the folding core from one parent protein and the remaining parts of the other. Both chimeras form active, well-folded RNases H. Stability curves, based on CD-monitored chemical denaturations, show that the chimera with the thermophilic core is more stable, has a higher midpoint of thermal denaturation, and a lower change in heat capacity (,Cp) upon unfolding than the chimera with the mesophilic core. A possible explanation for the low ,Cp of both the parent thermophilic RNase H and the chimera with the thermophilic core is the residual structure in the denatured state. On the basis of the studied parameters, the chimera with the thermophilic core resembles a true thermophilic protein. Our results suggest that the folding core plays an essential role in conferring thermodynamic parameters to RNases H. [source]


Distribution of arsenic species in the freshwater crustacean Procambarus clarkii

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 12 2002
V. Devesa
Abstract The concentrations of total arsenic and arsenic species in the complete organism of the crayfish Procambarus clarkii and its various parts (hepatopancreas, tail, and remaining parts) were analyzed in order to discover the distribution of arsenic and its species. With this information it will be possible to establish where the chemical forms of this metalloid tend to accumulate and what risks may derive from the contents and species present in the edible parts of this crustacean. The total arsenic content in the complete organism and in the various parts analyzed ranged from 2.5 to 12,µg g,1 dry mass (DM), with inorganic arsenic representing 18 to 34% of total arsenic. The arsenical composition varied according to the part of the crayfish considered. The hepatopancreas had the highest levels of total arsenic (9.2,12,µg g,1 DM) and inorganic arsenic (2.7,3.2,µg g,1 DM). The tail (edible part) had the lowest levels of both total arsenic (2.5,2.6,µg g,1 DM) and inorganic arsenic (0.46,0.64,µg g,1 DM). The predominant organoarsenical species were the dimethylarsinoylribosides: glycerol riboside in the hepatopancreas, sulfate riboside in the tail, and sulfonate and phosphate ribosides in the remaining parts. Copyright © 2002 John Wiley & Sons, Ltd. [source]