bluuebunny/crossref_metadata_2025 huggingface dataset:
c-Fos Facilitates the Acquisition and Extinction of Cocaine-Induced Persistent Changes
Authors: Zhang Jianhua , Zhang Lu , Jiao Hongyuan , Zhang Qi , Zhang Dongsheng , Lou Danwen , Katz Jonathan L. , Xu Ming
Published: December 2006

Development of drug addiction involves persistent neurobiological changes. The dopamine D1receptor is involved in mediating cocaine-induced neuroadaptation, yet the underlying intracellular mechanisms remain unclear. We examined a potential role of the immediate early geneFos, which is robustly and rapidly induced by cocaine via D1receptors, in mediating cocaine-induced persistent neurobiological changes by creating and analyzing a mouse in whichFosis primarily disrupted in D1receptor-expressing neurons in the brain. We show that the expression levels of several transcription factors, neurotransmitter receptors, and intracellular signaling molecules induced by repeated cocaine administration are altered inFos-deficient brains. Dendritic remodeling of medium spiny neurons induced by repeated exposure to cocaine is blunted in the mutant mice. The mutant mice exhibit attenuated behavioral sensitization after repeated exposure to cocaine and more persistent memory of cocaine-induced conditioned place preference. Our findings indicate that c-Fos produced in D1receptor-expressing neurons integrates mechanisms to facilitate both the acquisition and extinction of cocaine-induced persistent changes.
Neuron-Specific Conditional Expression of a Mitochondrially Targeted Fluorescent Protein in Mice
Authors: Chandrasekaran Krish , Hazelton Julie L. , Wang Yu , Fiskum Gary , Kristian Tibor
Published: December 2006

Mitochondrial dysfunction contributes to the pathophysiology of both acute and chronic neurodegenerative disorders. Quantification of mitochondrial bioenergetic properties generally requires the use of isolated brain mitochondria. However, the involvement of neuronal mitochondrial dysfunction in these disorders is limited by the lack of markers, and therefore isolation procedures, that distinguish neuronal compared with astrocyte mitochondria. To address this and other issues concerning neuronal mitochondria in the CNS, transgenic mice were generated that express a fluorescent protein targeted specifically to neurons. A neuron-specific promoter, CaMKIIα (calcium/calmodulin-dependent kinase IIα) driven tTA (tetracycline transactivator) mice were crossed with TRE (tetracycline responsive element) driven mitochondrial targeted enhanced yellow fluorescent protein (eYFP) mice. Expression of eYFP in the bigenic mouse brain was observed only in neuronal mitochondria of striatum, forebrain, and hippocampus and was enhanced by the removal of the tetracycline analog doxycycline (Dox) in the diet. The respiratory control ratio of synaptic and nonsynaptic mitochondria isolated from eYFP-expressing mice was the same as control mice, suggesting that neuronal mitochondria expressing eYFP maintain normal bioenergetic functions. More importantly, the development of Dox-inducible, neuron targeted mito/eYFP transgenic mice offer a uniquein vivomodel for delineating the participation of neuronal mitochondria in neuronal survival and death.
Auf die harte Tour – Physisch anstrengende Netzwerkspiele (Exertion Interfaces for Networked Games)
Authors: Mueller Florian ‚Floyd’
Published: December 2006

Obwohl Computerspiele dank Netzwerktechnik Spieler auf der ganzen Welt miteinander verbinden, wird ihnen vorgeworfen, zur Vernachlässigung zwischenmenschlicher Kontakte beizutragen. Traditionelle Freizeitbeschäftigungen wie Kegeln, Billard, Tischfussball und Airhockey hingegen werden als unterstützend für das soziale Miteinander angesehen, setzen aber durch die physische Interaktion voraus, dass sich die Spieler am gleichen Ort befinden. Airhockey over a Distance kombiniert die bewegungsintensive Interaktion mit den Vorteilen der Telekommunikationstechnik, um Spielern den Eindruck zu vermitteln, eine reale, physikalische Spielscheibe zwischen zwei örtlich voneinander getrennten Airhockeytischen durch das Netzwerk hin- und herzuschießen. Ein anderes Spiel namens Push‘N’Pull ist ebenso physisch anstrengend, verlangt aber Teamwork: Zwei örtlich voneinander getrennte Teilnehmer müssen in einem Spiel ihre Körperkräfte kooperativ einsetzen, um gemeinsam zum Ziel zu kommen. Dieses und andere neuartige Spiele, die solche kraftanstrengende Interfaces benutzen, versuchen den sozialen Charakter existierender Spiele aufzugreifen und um die Möglichkeiten der Netzwerktechnik zu erweitern. Dies ermöglicht es Teilnehmern, obwohl sie sich an verschiedenen Orten befinden können, ein geselliges Miteinander im Spiel zu erleben.
Estimating market risk with neural networks
Authors: Franke Jürgen , Diagne Mabouba
Published: December 2006

We consider stochastic volatility models for discrete financial time series of the nonlinear autoregressive-ARCH type with exogenous components.We discuss how the trend and volatility functions determining the process may be estimated nonparametrically by least-squares fitting of neural networks or, more generally, of functions from other parametric classes having a universal approximation property. We prove consistency of the estimates under conditions on the rate of increase of function complexity. The procedure is applied to the problem of quantifying market risk, i.e. of calculating volatility or value-at-risk from the data taking not only the time series of interest but additional market information into account. As an application, we study some stock prices series and compare our approach with the common method based on fitting a GARCH(1,1)-model to the data
Robust multivariate location estimation, admissibility, and shrinkage phenomenon
Authors: Jurečková Jana , Sen P. K.
Published: December 2006

Estimators of multivariate location parameters are generally dominated, in finite as well as asymptotic setups, by suitable shrinkage versions, and hence are inadmissible; such shrinkage estimators may not be admissible either. This feature is shared by maximum likelihood and many robust estimators. The interplay of robustness, admissibility and shrinkage phenomenon in some general multivariate location models (not necessarily elliptically or spherically symmetric) is illustrated and applied to Huber-type contamination models.
On local bootstrap bandwidth choice in kernel density estimation
Authors: Ziegler Klaus
Published: December 2006

Under mild regularity conditions, it is shown that bandwidth selection by minimizing the bootstrapped mean squared error (at a pointx) leads to a bandwidth of the same form as that obtained by a consistent plug-in procedure. The consequences of this observation for the construction of confidence intervals are also discussed.
Crystal structures of high-pressure phases in the alumina-water system: I. Single crystal X-ray diffraction and molecular dynamics simulation of η-Al(OH)3
Authors: Komatsu Kazuki , Kuribayashi Takahiro , Kudoh Yasuhiro , Kagi Hiroyuki
Published: December 2006

The high-pressure phase of gibbsite has been studied by in situ single crystal X-ray diffraction method and molecular dynamics (MD) simulation at 3.0 GPa. The crystal structure of the high-pressure phase, η-Al(OH)3, was successfully determined by direct methods based on the intensities of X-ray diffraction. The space group and lattice constants for η-Al(OH)3 are P21/b11 (#14), a = 8.612(3) Å, b = 5.013(2) Å, c = 9.194(5) Å and α = 90.34(6)°, respectively. The crystal structure of η-Al(OH)3 consists of an Al octahedral layer, and the layers are connected via H-bonds. The mechanism of the phase transition from gibbsite to η-Al(OH)3 is also discussed in the context of previously reported powder X-ray diffraction data.
Effect of hydrostatic pressure up to 6 GPa on the crystal structures of ammonium and sodium hexafluorosilicates, (NH4)2SiF6 and Na2SiF6; a phase transition in (NH4)2SiF6 at 0.2–0.3 GPa
Authors: Boldyreva Elena V. , Shakhtshneider Tatyana P. , Sowa Heidrun , Ahsbahs Hans
Published: December 2006

An in situ X-ray powder diffraction study has shown the cubic modification of (NH4)2SiF6 (cryptohalite, space group Fm¯3m) at 0.2–0.3 GPa to transform irreversibly into the trigonal bararite, space group P¯3m1. The anisotropy of lattice strain in the high-pressure phase of (NH4)2SiF6 was measured up to 6 GPa and compared with that in the trigonal Na2SiF6. The pressure-induced changes in the packing of (SiF6)2– anions were analyzed, the changes in the IR-spectra of (SiF6)2– ions induced by increasing pressure and on decompression were measured and compared for trigonal (NH4)2SiF6 and Na2SiF6.
Pigment Orange 5: crystal structure determination from a non-indexed X-ray powder diagram
Authors: Schmidt Martin U. , Buchsbaum Christian , Schnorr Jan M. , Hofmann Detlef W. M. , Ermrich Martin
Published: December 2006

Pigment Orange 5, also known as “Dinitroaniline Orange”, is an industrially produced azo pigment. The structure was solved from routinely measured lab X-ray powder data without indexing, by means of a newly developed combination of lattice energy minimization and simultaneous fit to the X-ray powder diagram. Finally, the structure was refined by Rietveld methods using restraints. Pigment Orange 5 crystallizes in space group P21/a with a = 16.365(5) Å, b = 12.874(4) Å, c = 6.924(2) Å, β = 100.143(2)°, Z = 2. The molecules are almost planar and form stacks along the c axis.
Preparation, spectra and thermal properties of two novel cyano-bridged complexes: crystal structure of one-dimensional copper(II)/palladium(II)
Authors: Karadağ Ahmet
Published: December 2006

Two new coordination polymers,{–M(hydeten)2–NC–Pd(CH)2–CN}n, [M = Ni and Cu, hydeten; N-(2-hydroxyethyl)-ethylenediamine)], have been synthesized and their elemental, thermal and spectroscopic (IR and UV-vis) properties have been studied. The crystal structure analysis of the Cu–Pd complex has indicated a polymeric chain –Cu(hydeten)2–NC–Pd(CN)2– Cu(hydeten)2– in which the Pd(II) ions are four-coordinated by carbon atoms from four cyano groups in a square-planar arrangement, whereas Cu(II) ions are six-coordinated with two cis cyano N and four N atoms of bidentate hydeten ligands in a distorted octahedral arrangement.
Controlled Release of Proteins Bound to Spherical Polyelectrolyte Brushes
Authors: Wittemann A. , Haupt B. , Ballauff M.
Published: December 2006

We discuss the interaction of proteins dissolved in aqueous solution with spherical polyelectrolyte brushes (SPB). The SPB consist of a solid core particle of colloidal dimensions (ca. 100 nm in diameter) onto which long polyelectrolyte chains have been grafted. Immersed in aqueous solution of proteins these SPB will take up high amounts of protein if the ionic strength is low. At high ionic strength, however, virtually no protein will enter into the brush layer attached to the surface of the core particles. We show that bovine serum albumin (BSA) bound at low ionic strength will gradually be released upon raising the salt concentration in the solution in a well-controlled manner: For each raise of the ionic strength in solution there is a well-defined amount of protein that is released. We show that BSA adsorbed to a conventional carboxylated latex will not be released if treated in the same manner. All findings, namely the uptake of protein as well as the controlled release can be explained by the “counterion release force”: Patches of positive charge on the surface of the proteins which are immersed in the brush layer become multivalent counterions of the polyelectrolyte chains thus releasing a concomitant number of counter- and coions. Release of counterions as induced by the adsorption of proteins is hence the main driving force for the polyelectrolyte-mediated protein adsorption (PMPA).
Adsorption of the Flexible Salivary Proteins Statherin and PRP-1 to Negatively Charged Surfaces – A Monte Carlo Simulation and Ellipsometric Study
Authors: Skepö Marie , Lindh Lieselott , Arnebrant Thomas
Published: December 2006

The structural properties of the salivary proteins, acidic proline rich PRP-1 and statherin, adsorbed onto negatively charged surfaces have been studied by Monte Carlo simulations and ellipsometry. It is shown that both proteins adsorb to negatively charged surfaces, although their net charges are negative. Experimentally, an initial fast mass-controlled film build-up was detected for both proteins, and plateaus were reached within 10 min. The isotherm shape and the adsorbed amounts were similar for PRP-1 to hydrophilic and hydrophobic surfaces, while statherin adsorbs to a greater extent to the hydrophobic surface. These results could be explained from the simulation results by considering the proteins as diblock polyampholytes. It has also been shown that the adsorption of PRP-1 to a negatively charged surface may be purely electrostatically driven, while pure electrostatic interaction is not sufficient to drive adsorption of statherin,i.e., an extra short-ranged attractive interaction is necessary to account for the experimental observations.
Adsorption of Amyloid β (1-40) Peptide at Liquid Interfaces
Authors: Brezesinski Gerald , Maltseva Elena , Möhwald Helmut
Published: December 2006

The folding of amyloid β (1-40) peptide into β-sheet containing fibrils, which are the main components of deposits and plaques in some neurodegenerative diseases, is thought to play a causative role in Alzheimer's disease. The peptide is amphiphilic and therefore surface active. Interactions with surfaces can play an important role in the secondary structure changes. Langmuir monolayers of zwitterionic (DMPC, DPPC, DMPE, DPPE) as well ionic (DMPG, DPPG, DPTAP, DSTAP) phospholipids have been used to study the influence of the peptide on the lipid packing and, vice versa, the influence of phospholipid monolayers on the peptide secondary structure by infrared reflection absorption spectroscopy and grazing incidence X-ray diffraction. The peptide adsorbs at the air/water (buffer) interface and penetrates into uncompressed phospholipid monolayers. After a special pre-treatment, the peptide forms predominantly a random-coil secondary structure in solution but adopts a β-sheet conformation, which is almost parallel oriented to the surface in the adsorbed state. The peptide does not influence the condensed phospholipid monolayer structure. In contrast to Aβ insertion into zwitterionic or anionic phospholipid monolayers, a non β-sheet structure was detected during the first stage of Aβ insertion into positively charged monolayers. At high lateral pressure, the peptide is squeezed out of the monolayer. It desorbs completely from zwitterionic monolayers and charged monolayers on buffer, but remains adsorbed in β-sheet conformation at charged monolayers on water. In contrast, Aβ remains in a fluid (disordered) and charged monolayer on buffer even above 30 mN m-1. This observation shows that a combination of hydrophobic and electrostatic interactions is necessary to keep the peptide in the adsorbed state at high pressure on buffer.
RACIAL CAMP in The Producers and Bamboozled
Authors: GUBAR SUSAN
Published: December 2006

ABSTRACT In Bamboozled (2001), Spike Lee extends Mel Brooks's camping of race in The Producers (1968), but how do their movies illuminate racial history? Taken together, both spoof American cultural industries, even as they prove that America provided an escape from genocidal violence for Jews but an entrapment within it for blacks.
Behaviour of interlocking mortarless block masonry
Authors: Jaafar M. S. , Alwathaf A. H. , Thanoon W. A. , Noorzaei J. , Abdulkadir M. R.
Published: December 2006

Various types of interlocking mortarless (dry-stacked) block masonry system have been developed worldwide. However, the characteristics of dry joints under compressive load, and their effect on the overall behaviour of the interlocking mortarless system, are still not well understood. This paper presents an experimental investigation into the dry-joint contact behaviour of masonry and the behaviour of interlocking mortarless hollow blocks for grouted and ungrouted prisms under compression. Two experimental test set-ups are proposed to evaluate the contact behaviour of dry joints, considering the geometric imperfections in the contacting faces. The results show that the contact behaviour of a dry joint is highly affected by geometric imperfections in the block bed. Different patterns of deformation are distinguished in mortarless hollow (ungrouted) and grouted prisms. Dry joints predominantly affected the hollow prism deformation until the compressive load reaches 0·57 of the maximum load. However, this behaviour is not common in grouted prisms, because noticeable deformation commences after 0$38 of the maximum load. Furthermore, the variations of strength and deformation in grouted specimens are diminished compared with those in ungrouted specimens.
Transplacental transfer of organochlorines in california sea lions (Zalophus californianus)
Authors: Greig Denise J. , Ylitalo Gina M. , Hall Ailsa J. , Fauquier Deborah A. , Gulland Frances M.D.
Published: December 2006

The transplacental transfer of organochlorines (OCs) in California sea lions (Zalophus californianus) was investigated by analyzing blubber samples from 20 female sea lions and their fetuses during the last trimester of pregnancy. A rapid, high-performance liquid chromatographic, photodiode-array method was used to measure blubber concentrations of polychlorinated biphenyls (PCBs), including dioxin-like congeners, as well as DDTs and hexachlorobenzene. Summed values of PCBs (ΣPCBs), of DDTs (ΣDDTs), and of PCB toxic equivalents (ΣPCB TEQs) were calculated from these data. The ratios of mean blubber concentrations of fetal ΣPCBs to maternal blubber concentrations of ΣPCBs were 0.45 by wet weight and 0.97 by lipid weight, but these ratios varied widely among mother–fetus pairs. Mean ratios of fetal ΣDDTs to maternal ΣDDTs were 0.53 by wet weight and 1.12 by lipid weight. Fetuses were classified into two age groups, based on date of recovery, to examine differences in OC transfer because of gestational age. Fetal to maternal ratios for individual PCB congeners, DDT compounds, and ΣPCBs, ΣDDTs, and ΣPCB TEQs were lower among premature compared with late-term fetuses. These ratios increased for both groups as the logarithmic n-octanol/water partition coefficient (log Kow) for each compound decreased. Linear predictions for ΣPCB and ΣDDT concentrations in fetal blubber could be obtained using the ΣPCB and ΣDDT concentrations in maternal blubber, maternal and fetal blubber lipid content, maternal mass, and maternal age. Fetal TEQ was explained by maternal TEQ and maternal age. The ability to predict contaminant concentrations in fetal blubber from maternal parameters is important for developing risk assessment models for marine mammals.
Marine sediment toxicity identification evaluation methods for the anionic metals arsenic and chromium
Authors: Burgess Robert M. , Perron Monique M. , Cantwell Mark G. , Ho Kay T. , Pelletier Marguerite C. , Serbst Jonathan R. , Ryba Stephan A.
Published: December 2006

Marine sediments accumulate a variety of contaminants and, in some cases, demonstrate toxicity because of this contamination. Toxicity identification evaluation (TIE) methods provide tools for identifying the toxic chemicals causing sediment toxicity. Currently, whole-sediment TIE methods are not available for anionic metals like arsenic and chromium. In the present paper, we describe two new anion-exchange resins used in the development of whole-sediment TIE methods for arsenic and chromium. Resins were shown to reduce whole-sediment toxicity and overlying water concentrations of the anionic metals. Sediment toxicity, expressed as the median lethal concentration, was reduced by a factor of two to a factor of nearly six between amended sediment treatments containing resin and those without resin. Aqueous concentrations of arsenic and chromium in the toxicity exposures decreased to less than the detection limits or to concentrations much lower than those measured in treatments without resin. Interference studies indicated that the anion-exchange resins had no significant effect on concentrations of the representativepesticide endosulfan and minimal effects on concentrations of ammonia. However, the anion-exchange resins did significantly reduce the concentrations of a selection of cationic metals (Cd, Cu, Ni, Pb, and Zn). These data demonstrate the utility of anion-exchange resins for determining the contribution of arsenic and chromium to whole-sediment toxicity. The present results also indicate the importance of using TIE methods in a formal TIE structure to ensure that results are not misinterpreted. These methods should be useful in the performance of marine whole-sediment TIEs.
An integrated model describing the toxic responses ofDaphnia magnato pulsed exposures of three metals
Authors: Hoang Tham C. , Tomasso Joseph R. , Klaine Stephen J.
Published: December 2006

Some toxicology research in which toxicant exposures are continual (pulsed) rather than continuous have been reported. A number of toxicity models have been developed for pulsed and continuous exposures. Most of these models were developed based on one- or two-compartment, first-order toxicokinetics and were calibrated with organic compounds. In the present study, the relationship between mortality (after 21 d) of Daphnia magna in response to pulsed and continuous exposures to Cu, Zn, and Se was used to develop a model that integrated the effects of single and multiple pulsed metal exposures based on first-order uptake and depuration kinetics. Mortality was a function of exposure concentration, duration, and recovery time between exposures. The model was successfully validated using an independent data set. It is applicable to risk assessment and, potentially, may be incorporated with other models (e.g., the biotic ligand model) to predict the toxicity of pulsed metal exposures under a range of environmental conditions.
Risk assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 3: Studies on native species
Authors: Venturino Andrés , Montagna Cristina Mónica , de D'Angelo Ana María Pechen
Published: December 2006

We evaluated the potential environmental risk of the herbicide Magnacide® (Baker Petrolite, TX, USA) using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth, Buenos Aires, Argentina. Six species including fish, toads, snails, crustaceans, and insects were selected to perform studies on acute toxicity and repeated exposure effects. Magnacide H susceptibility ranking was Bufo arenarum (lethal concentration 50 [LC50] = 0.023 mg/L), Onchorhynchus mykiss (LC50 = 0.038 mg/L), Heleobia parchappii (LC50 = 0.21 mg/L), Hyalella curvispina (LC50 = 0.24 mg/L), Simulium spp. (LC50 = 0.60 mg/L), and Chironomus spp. (LC50 = 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70 to 90% of the species up to 20 km downstream from the application point. Repeated exposures to Magnacide H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures, showing no cumulative effects. Whether short-term exposures may result in long-term sublethal effects on the organism's life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that Magnacide H application schedule is extremely toxic for most native species at CORFO–Río Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities.
Environmental effect assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). tier 4: In situ survey on benthic invertebrates
Authors: Albariño Ricardo , Venturino Andrés , Montagna Cristina Mónica , de D'Angelo Ana María Pechen
Published: December 2006

The objective of this study was to assess the effects of Magnacide® H (Baker Petrolite, TX, USA) usage on the aquatic ecosystem at the Cooperativa de Riego y Fomento (CORFO)–Río Colorado irrigation channels, analyzing the effects on benthic invertebrates. At recommended treatment concentrations, Magnacide H kills most of the aquatic organisms; however, its presence in the channels is transient. Magnacide H caused a significant reduction in the number of taxa (58%), abundance (57%), and community diversity (67%) in the benthic assemblage with respect to untreated channels during the application period in the first year of the study. The herbicide reduced the abundance of the most abundant taxa: oligochaetes, chironomids, ostracods, and the snails Biomphalaria peregrina and Heleobia parchappii. In contrast, the herbicide only reduced invertebrate diversity during the application period at the second year of study. Two months after the applications had ceased, the benthic community in treated channels recovered their biotic attributes, reaching values similar to controls. Recovery could have occurred from upstream unimpaired reaches supplying migrating invertebrates that recolonized affected areas. Since recovery occurred within a reasonable period of time, we conclude that the impact of Magnacide H at CORFO–Río Colorado channels is acceptable from a regulatory point of view in the present practice protocol. Nevertheless, a strict control on the application conditions must be ensured to minimize the risk on the ecological receptors. We emphasize the recommendation that water release outside the channels is prevented until the product has dissipated.
Expression pattern of metallothionein, MTF-1 nuclear translocation, and its dna-binding activity in zebrafish (Danio rerio) induced by zinc and cadmium
Authors: Chen Wen-Ya , John Joseph Abraham Christopher , Lin Cheng-Hui , Chang Chi-Yao
Published: December 2006

Metallothionein is a small (6-kDa), cysteine-rich protein expressed by a six–zinc finger protein called metal-responsive element–binding transcription factor-1 (MTF-1) in response to Zn and Cd. Our previous reports have shown the basal expression of metallothionein (mt) and MTF-1 (mtf-1) genes in embryo and early larval stages of zebrafish (Danio rerio). In the present study, we investigated the mt expression in zebrafish early larvae induced by exposure to Cd and Zn (48, 72, 96, and 120 h postfertilization). Whole-mount in situ hybridization showed that Zn induced mt expression in the olfactory pit, cerebellum, ceratobranchials, liver, chloride cells, and neuromasts of the lateral line. Cadmium also induced mt expression in all the above regions except the cerebellum. Using fluorescence techniques, we have shown that Zn and Cd mediate cytoplasmic and nuclear translocation of MTF-1–enhanced green fluorescent protein fusion protein in zebrafish liver cell line. The MTF-1 protein was produced recombinantly by inserting zebrafish mtf-1 cDNA (1.8 kb) into pET-20b(+) expression vector and expressing in Escherichia coli BL21 (DE3) pLysS host strain competent cell on induction with isopropyl-β-D-thiogalactopyranoside. The protein was then purified by affinity chromatography on a nickel–nitrilotriacetic acid column. Electrophoretic mobility shift assay revealed binding of the recombinant MTF-1 in response to Zn and Cd at the putative metal-responsive elements (MREs) in the promoter region of the mt gene. Taken together, these results suggest that Zn and Cd are efficiently involved with mt expression induced in zebrafish embryos and with MTF-1 nuclear translocation and that this induction is achieved through the activation of MTF-1 binding at the MREs.
Bioaccumulation of the hepatotoxic microcystins in various organs of a freshwater snail from a subtropical Chinese Lake, Taihu Lake, with dense toxic Microcystis blooms
Authors: Zhang Dawen , Xie Ping , Liu Yaqin , Chen Jun , Liang Gaodao
Published: December 2006

In this paper, we describe the seasonal dynamics of three common microcystins (MCs; MC-RR, MC-YR, and MC-LR) in the whole body, hepatopancreas, intestine, gonad, foot, remaining tissue, and offspring of a freshwater snail, Bellamya aeruginosa, from Gonghu Bay of Lake Taihu, China, where dense toxic Microcystis blooms occur in the warm seasons. Microcystins were determined by liquid chromatography electrospray ionization mass spectrum. Microcystin (MC-RR + MC-YR + MC-LR) content of the offspring and gonad showed high positive correlation, indicating that microcystins could transfer from adult females to their young with physiological connection. This study is the first to report the presence of microcystins in the offspring of the adult snail. The majority of the toxins were present in the intestine (53.6%) and hepatopancreas (29.9%), whereas other tissues contained only 16.5%. If intestines are excluded, up to 64.3% of the toxin burden was allocated in the hepatopancreas. The microcystin content in the intestine, hepatopancreas, and gonad were correlated with the biomass of Microcystis and intracellular and extracellular toxins. Of the analyzed foot samples, 18.2% were above the tolerable daily microcystin intake recommended by the World Health Organization (WHO) for human consumption. This result indicates that public health warnings regarding human ingestion of snails from Taihu Lake are warranted. In addition, further studies are needed to evaluate the occurrence by Microcystis in relation to spatial and temporal changes in water quality.
Mercury bioaccumulation in green frog (Rana clamitans) and bullfrog (Rana catesbeiana) tadpoles from Acadia National Park, Maine, USA
Authors: Bank Michael S. , Crocker Jeff , Connery Bruce , Amirbahman Aria
Published: December 2006

Mercury contamination in the northeastern United States, including Acadia National Park (ANP; ME, USA), is well documented and continues to be a public health issue of concern. Mercury contamination of wild amphibians has received little attention, however, despite reports of worldwide population declines. Here, we report total Hg and methyl Hg (MeHg) concentrations for water, sediment, and green frog (Rana clamitans) and bullfrog (Rana catesbeiana) tadpoles (age, approximately one year) from ANP. Total Hg concentrations (mean ± standard error) in green frog and bullfrog tadpoles were 25.1 ± 1.5 and 19.1 ± 0.8 ng/g wet weight, respectively. Mean total Hg was highest for green frog tadpoles sampled from the Schooner Head site (ANP, Bar Harbor, ME, USA), a small, semipermanent beaver pond where Ranavirus was detected during the summer of 2003 sampling period. Methyl Hg comprised 7.6 to 40% of the total Hg in tadpole tissue (wet-wt basis), and mean total Hg levels in tadpoles were significantly different among pond sites (n = 9). Total Hg in pond water was a significant predictor of tadpole total Hg levels. Dissolved organic carbon was a significant predictor of both total Hg and MeHg in water, and total Hg in water also was strongly correlated with MeHg in water. Of the nine pond ecosystems sampled at ANP, 44% had a methylation efficiency (water MeHg to total Hg ratio) of greater than 10%, and 33% had total Hg levels in sediment that were approximately equal to or greater than the established threshold level effect concentration for freshwater sediments (0.174 mg/kg dry wt). Our data indicate that wetland food webs in ANP likely are susceptible to high levels of total Hg bioaccumulation and that methylation dynamics appear to be influenced by local abiotic and biotic factors, including disturbances by beavers and in situ water chemistry patterns. These findings may be important to National Park Service resource managers, especially considering the class I airshed status of ANP and the strong potential for negative effects to aquatic ecosystem structure and function from Hg pollution.
Investigation of a High Temperature Organic Water Shutoff Gel: Reaction Mechanisms
Authors: Al-Muntasheri Ghaithan A. , Nasr-El-Din Hisham A. , Peters Joop , Zitha Pacelli L.J.
Published: December 2006

Water production during oil and gas recovery is a longstanding problem that is becoming critical with maturing fields worldwide. Lifting, processing, treating, and reinjection of the unwanted water add to the overall oil production costs. Also, water disposal may pose environmental problems. Recent statistical studies indicate that processing unwanted water costs the oil industry nearly U.S. $40 billion per year.

Polymer gels have been widely used as blocking agents for excessive water production. In this study, two different polymers were crosslinked with polyethyleneimine (PEI). The first is a copolymer of polyacrylamide tert-butyl acrylate (PAtBA), and the second is a polyacrylamide (PAM). The PAtBA/PEI system was previously shown to be stable at temperatures up to 160°C, typical of those encountered in deep oil and gas reservoirs. However, the crosslinking mechanisms of this system at high temperatures have not been well defined.

This study examined the structural changes of PAtBA using C-13 nuclear magnetic resonance (NMR) spectroscopy. Understanding these changes is a first step toward the identification of the crosslinking mechanisms of PAtBA and PAM with PEI. This will have a strong impact on the design of water shutoff treatments utilizing these systems.

Introduction

As oil and gas fields mature, larger volumes of water are produced. Separating, treating, and disposing this water add extra costs to the petroleum production. It has been reported that the petroleum industry spends several tens of billions of dollars to deal with excessive water production (Bailey et al. 2000).

Hydrophilic polymer gels have been widely used to reduce (Zaitoun and Kohler 1988) or completely block (Hutchins et al. 1996.water from its producing zones. Polyacrylamides have been the most commonly used base polymers crosslinked with either inorganic or organic crosslinkers. Inorganic crosslinkers include Cr+3, Al+3, and Zr+4 and have been mostly utilized to crosslink partially hydrolyzed polyacrylamide (HPAM). Inorganically crosslinked gels result from the ionic bonding between the negatively charged carboxylate groups and the multivalent cation (Prud'homme et al. 1983; Lockhart 1994; te Nijenhuis et al. 2003).

Organic crosslinkers were introduced to obtain gels that are stable over a wider temperature range (Moradi-Araghi 1991; Albonico et al. 1994; Hardy et al. 1999). This is possible because in this case, the crosslinking is done by a covalent bonding, which is much more stable than ionic bonds. The covalent bonds often involve the amide groups on the polymer backbone. A typical example of an organically crosslinked gel is the polyacrylamide-phenol/formaldehyde system, which has been reported to be stable at 121 DEGREE C for 13.3 years (Moradi-Araghi 2000, 1993). However, its toxicity has limited its broad use in the field. Chemical alternatives for the phenol/formaldehyde system were also reported (Moradi-Araghi 1994; Dovan et al. 1997).
Temperature tuning of polarization mode dispersion in single-core and two-core photonic liquid crystal fibers
Authors: Lesiak P. , Woliński T. , Brzdąkiewicz K. , Nowecka K. , Ertman S. , Karpierz M. , Domański A. , Dąbrowski R.
Published: December 2006

In this paper we present numerical and experimental results of propagation and polarization properties of the photonic liquid crystal fibers (PLCFs) in which only selected micro holes were filled with nematic liquid crystal (LC) guest materials. As a host photonic crystal fiber (PCF) structure, we used a commercially available highly birefringent PCF (Blazephotonics, UK). A tunable laser operated at infrared has powered the PLCFs under investigation infiltrated by the 1550 nematic LC synthesized at the Military University of Technology. Temperature induced changes of the polarization mode dispersion (PMD) as well switching between fundamental and higher order modes and also single-core and two-core propagation were successfully demonstrated.
Electrophysical properties of a system with induced antiferroelectric phase comprising cyano compound
Authors: Skrzypek K. , Tykarska M. , Piecek W.
Published: December 2006

The DSC, electrooptic and X-ray results for the system composed of two synclinic compounds CNCH2COO(CH2)6OphPhCOOPhCOOC*H(CH3)C6H13 and C5H11COO(CH2)3OPhCOOPhPhCOOC*H(CH3)C6H13 are presented. The antiferroelectric SmC*A phase induces in this system and it was confirmed by physical measurements. It was found out that the mechanism of SmC*A phase induction is different than in systems comprising compound with perfluoroalkyl chain.
REACH – Opportunities and Risks for a Company Supplying Research Chemicals and Intermediates
Authors: Marfurt Stephan
Published: December 2006

REACH is the proposal of a new legislation to control chemicals in the EU and poses a major challenge to suppliers of chemicals. As a company engaged in supplying more than 80'000 individual substances to a very diverse customer base, Sigma-Aldrich is particularly affected. The impact
of various aspects of REACH, both positive and negative, is discussed. Although the legislation is not yet available in its final version the overall impact is believed to be negative.
University of Zurich Hosts Symposium in Honor of Professor Heinz Heimgartner
Authors: Rahm Annette
Published: December 2006

The Institute of Organic Chemistry of the University of Zürich hosted a symposium in honor of Prof. Heinz Heimgartner on June 9, 2006. PO Dr. Simon M. Ametamey, Dr. Kurt Dietliker, Prof. Grzegorg Mloston, Dr. Daniel Obrecht, Prof. José Villalgordo and Prof. Peter Wipf, all
former graduate students and collaborators of the Heimgartner group gave insight into their research efforts that are still connected to greater or lesser extent to Prof. Heimgartner's main research interest in heterocyclic chemistry.
Discovery of transport and reaction properties in distributed systems
Authors: Zhang Libin , Kulkarni Kedar , Somayaji MahadevaBharath R. , Xenos Michalis , Linninger Andreas A.
Published: December 2006

In distributed systems, transport phenomena coupled with chemical or metabolic reactions are functions of space. A computational method is outlined to acquire unknown system properties in distributed systems by problem inversion. Physical and chemical properties are estimated simultaneously. The finite‐volume discretization method formulated in generalized curvilinear coordinates applied to inversion problem of arbitrarily complex geometries. The direct solution approach of the reacting transport problem through inexpensive acquisition of sensitivity information is presented. An inexact trust region method improves the convergence rate of the large‐scale transport and kinetic inversion problem (TKIP). The case studies demonstrate a novel computational approach for quantifying unknown transport properties, as well as reaction or metabolic constants. Solutions to technological challenges is presented in computational fluid mechanics and biotransport using mathematical programming techniques for inversion of distributed systems. © 2006 American Institute of Chemical Engineers AIChE J, 2006
News cues: Information scent and cognitive heuristics
Authors: Sundar S. Shyam , Knobloch‐Westerwick Silvia , Hastall Matthias R.
Published: December 2006

Google News and other newsbots have automated the process of news selection, providing Internet users with a virtually limitless array of news and public information dynamically culled from thousands of news organizations all over the world. In order to help users cope with the resultant overload of information, news leads are typically accompanied by three cues: (a) the name of the primary source from which the headline and lead were borrowed, (b) the time elapsed since the story broke, and (c) the number of related articles written about this story by other news organizations tracked by the newsbot. This article investigates the psychological significance of these cues by positing that the information scent transmitted by each cue triggers a distinct heuristic (mental shortcut) that tends to influence online users' perceptions of a given news item, with implications for their assessment of the item's relevance to their information needs and interests. A large 2 × 3 × 6 within‐subjects online experiment (N = 523) systematically varied two levels of the source credibility cue, three levels of the upload recency cue and six levels of the number‐of‐related‐articles cue in an effort to investigate their effects upon perceived message credibility, newsworthiness, and likelihood of clicking on the news lead. Results showed evidence for source primacy effect, and some indication of a cue‐cumulation effect when source credibility is low. Findings are discussed in the context of machine and bandwagon heuristics.
Fighting child pornography: Exploring didactics and student engagement in social informatics
Authors: Godejord Per Arne
Published: December 2006

This article describes a unique educational project that was implemented in the undergraduate study of computer science in 2002. Nesna University College has been using the example of sexual abuse of children in case study teaching in social informatics, in order to create an environment for intrinsically motivated learning. The project also gave the students a unique opportunity to get involved both emotionally and practically in the field of social informatics. The project is run in cooperation with Save the Children Norway and the Norwegian National Crime Squad. Nesna University College has the only computer science program in the world that has sexual abuse of children as the main topic on the curriculum. The computer science students provide both the Save the Children Norway and the National Criminal Investigation Service with reports on various topics such as secure chat, camera phones and possible abuse, Freenet as a tool for sexual abuse, etc. This exceptional cooperation between higher education and public and private organizations in this field makes the project not only unique, but might also be a major factor in both the willingness of students to learn social informatics and their development of skills in the various topics of social informatics.
Quick multivariate kernel density estimation for massive data sets
Authors: Cheng K. F. , Chu C. K. , Lin Dennis K. J.
Published: December 2006

Massive data sets are becoming popular in this information era. Due to the limitation of computer memory space and the computing time, the kernel density estimation for massive data sets, although strongly demanding, is rather challenging. In this paper, we propose a quick algorithm for multivariate density estimation which is suitable for massive data sets. The term quick is referred to indicate the computing ease. Theoretical properties of the proposed algorithm are developed. Its empirical performance is demonstrated through a credit card example and numerous simulation studies. It is shown that in addition to its computational ease, the proposed algorithm is as good as the traditional methods (for the situations where these traditional methods are feasible). Copyright © 2006 John Wiley & Sons, Ltd.
Science, engineering, and statistics
Authors: Davis T. P.
Published: December 2006

Symmetry and parsimony, together with unification through synthesis are important principles that govern the character of physical law. We show how these principles can be applied to engineering to develop an approach to reliability, and engineering in general, that centres on the identification, detection, and avoidance of failure modes through design. A definition of reliability, not presented in terms of probability, but rather based on physics, geometry, and the properties of materials, will be emphasized to support this approach. We will also show how the nature of the inductive–deductive learning cycle provides the framework for statistical science to be embedded into engineering practice, with particular regard to improving reliability through failure mode avoidance. Copyright © 2006 John Wiley & Sons, Ltd.
Measurement error bias in pharmaceutical cost‐effectiveness analysis
Authors: C. Marschner Ian
Published: December 2006

Drug development in the pharmaceutical industry is increasingly influenced by measures of cost‐effectiveness, such as cost per life‐year gained, and some governments make decisions about whether to pay for drugs based on cost‐effectiveness considerations. While cost per life‐year gained is a key measure of cost‐effectiveness, costs associated with the intermediate outcome of improving a biomarker, such as cholesterol level or blood pressure, provide important supplementary information, particularly where mortality data may be limited. In this case, cost‐effectiveness can be interpreted as the additional cost per unit time of achieving an additional beneficial biomarker response to treatment. A problem in this context is that biomarker assessment is typically subject to measurement error which leads to bias in assessing the benefit of a drug, and hence in the assessment of its cost‐effectiveness. We discuss the adjustment of cost‐effectiveness analyses for measurement error and consider the potential magnitude of bias that can arise. Using example calculations in the context of cholesterol‐lowering therapy, it is demonstrated that such biases can be significant, leading to costs being overestimated by in excess of 25%. Ignoring measurement error in cost‐effectiveness analyses can, therefore, have a substantial effect on the interpretation of such analyses. Copyright © 2006 John Wiley & Sons, Ltd.
On goodness‐of‐fit for homogeneity and proportional hazards
Authors: Bagdonavičius Vilijandas , Nikulin Mikhail
Published: December 2006

The classical goodness‐of‐fit tests for homogeneity and proportional hazards have small power in the case of alternatives when crossings of survival functions are possible. We give test statistics which are oriented against wide classes of alternatives including single or multiple crossings of survival functions. The limit distributions of the test statistics are derived. Power of some tests are investigated by simulation. Copyright © 2006 John Wiley & Sons, Ltd.
Examining the effects of customer service management (CSM) on perceived business performance via structural equation modelling
Authors: Yap Bee Wah , Khong Kok Wei
Published: December 2006

Structural equation modelling (SEM) is a useful multivariate technique to investigate the causal relationships between variables. This paper uses SEM to model the relationships between critical success factors (CSFs) of business process reengineering (BPR) implementations, customer service management (CSM) and perceived business performance (PBP) in Malaysian banking institutions. SEM results show that Management Competence has significant positive effects on PBP and CSM. Information technology (IT) infrastructure capabilities has significant effects on CSM but statistically insignificant (but positive) effect on PBP. Similarly Effective Process Redesign has statistically insignificant (but positive) effect on CSM and PBP. Results also show that CSM has a positive and significant association with PBP. Copyright © 2006 John Wiley & Sons, Ltd.