bluuebunny/crossref_metadata_2025 huggingface dataset:
Violent and Nonviolent Delinquent Behavior Among Caucasian and Hispanic Youth in Mental Health Systems-of-Care Programs
Authors: Azur Melissa J. , Godoy Garraza Lucas , Goldweber Asha
Published: August 2010

The prevention and reduction of violent and nonviolent delinquent behavior is a public health priority. In recent years, attention has turned to ethnic disparities in delinquent behavior in efforts to target programs to youth at greatest risk. This study uses longitudinal data from a national evaluation of a federally funded children’s mental health systems-of-care program to examine self-reported delinquent and violent behavior among Caucasian and Hispanic youth who entered mental health services between 1997 and 2006. The results from hierarchical logistic regressions indicate that delinquent, but not violent behavior, decreased over time. There were no significant ethnic differences between these youth in either delinquent or violent behavior. Sociodemographic, clinical, and school characteristics were associated with delinquency and offer suggestions on where to intervene. Given that mental health problems and delinquent behavior frequently co-occur, juvenile justice and mental health agencies would benefit from close partnerships to help youth address these problems.
Fear of In-School Victimization: Contextual, Gendered, and Developmental Considerations
Authors: Swartz Kristin , Reyns Bradford W. , Henson Billy , Wilcox Pamela
Published: August 2010

This study explores gendered and age-graded effects of key theoretical predictors of fear of crime among a panel of approximately 4,000 public middle and high school students in Kentucky. Theoretically, fear of school crime is presumed to be driven by individual-level indicators of vulnerability, as well as by school-level indicators of crime/disorder and social integration. Multilevel analysis revealed little effect of school-level contextual factors, whereas the key individual-level indicators of vulnerability were quite robust in their effects across male and female students. Further analysis, however, revealed that school context in the form of school-level delinquency significantly moderated the effect of individual-level perceived risk of victimization on fear for female students especially. Results provided little evidence of age-dependent correlates. In one exception, the positive effect of perceived risk of victimization on both male and female student fear declined, as students moved from the 7th grade to the 10th grade.
Leading aesthetically in uncertain times
Authors: Bathurst Ralph , Jackson Brad , Statler Matt
Published: August 2010

‘Leading Aesthetically’ highlights the processes by which leaders can inspire and motivate using sense perceptions that go beyond rational, objective, communication. In this article, we contribute to the theoretical development of aesthetic leadership by drawing on phenomenologist Roman Ingarden’s notions of presencing and concretization; backward reflexivity; attention to both form and content; and myth-making. We illustrate the particular relevance of these theoretical concepts to leadership in conditions of uncertainty and crisis by discussing the case of Hurricane Katrina’s impacts on New Orleans in 2005. The article concludes that aesthetically-aware leaders are able to deploy a range of intellectual and emotional skills that can complement more conventional rational-instrumental decision-making approaches in ways that can have considerable benefits in times of uncertainty, and most especially in crisis situations.
Developing the artist-leader
Authors: Woodward J. Brian , Funk Colin
Published: August 2010

Our leaders are challenged to lead in a world of increasing ambiguity and complexity, to make sense and to take effective action. The field of organization studies has developed a growing interest in ‘aesthetics’ in part as a response to such unprecedented conditions. From this perspective leaders require a new capacity comprised of aesthetic judgment, a perceptual stance and an ability to create plausible narratives of the world. The exercise of this aesthetic capacity is seen through the artistry shown by the Artist-Leader. The question of how to develop this capacity in leaders then becomes the primary challenge for designers. The current predominant approach to leader development is limited for this task, so the pedagogical approach outlined here draws predominantly on an aesthetically-informed hermeneutics. The concept of the aesthetic encounter, with its underlying conditions, is posited as the means for fostering the artist-leader’s innate imagination.
Ugly Betty goes global
Authors: Miller Jade L.
Published: August 2010

Betty la Fea , the phenomenally popular Colombian telenovela, has been exported as both canned (e.g. either dubbed or unaltered) programming and format to approximately 70 countries, including the recent US prime-time hit Ugly Betty. Guided by an examination of the extended global success of this Colombian production, this article explores the telenovela as a cultural product that is successful because of its appeal on both the local and global level, and as an economic product traversing a global industry. Popular telenovelas succeed as both canned programming and formats because they combine universally appealing stories (rags-to-riches) and style (melodrama) with localizable specifics with which viewers can easily identify. While telenovelas are localized products produced to first achieve domestic success, the cross-ownership structure of and multinational flows that mark the telenovela industry render any conception of telenovelas as South-to-North contra-flows of culture inherently problematic. Instead, this article argues that telenovelas can best be understood as localizable yet universally appealing cultural products traversing global networks of capitalist cultural concerns.
Microbial oxidation of arsenite in a subarctic environment: diversity of arsenite oxidase genes and identification of a psychrotolerant arsenite oxidiser
Authors: Osborne Thomas H , Jamieson Heather E , Hudson-Edwards Karen A , Nordstrom D Kirk , Walker Stephen R , Ward Seamus A , Santini Joanne M
Published: August 2010

Background

Arsenic is toxic to most living cells. The two soluble inorganic forms of arsenic are arsenite (+3) and arsenate (+5), with arsenite the more toxic. Prokaryotic metabolism of arsenic has been reported in both thermal and moderate environments and has been shown to be involved in the redox cycling of arsenic. No arsenic metabolism (either dissimilatory arsenate reduction or arsenite oxidation) has ever been reported in cold environments (i.e. < 10°C).

Results

Our study site is located 512 kilometres south of the Arctic Circle in the Northwest Territories, Canada in an inactive gold mine which contains mine waste water in excess of 50 mM arsenic. Several thousand tonnes of arsenic trioxide dust are stored in underground chambers and microbial biofilms grow on the chamber walls below seepage points rich in arsenite-containing solutions. We compared the arsenite oxidisers in two subsamples (which differed in arsenite concentration) collected from one biofilm. 'Species' (sequence) richness did not differ between subsamples, but the relative importance of the three identifiable clades did. An arsenite-oxidising bacterium (designated GM1) was isolated, and was shown to oxidise arsenite in the early exponential growth phase and to grow at a broad range of temperatures (4-25°C). Its arsenite oxidase was constitutively expressed and functioned over a broad temperature range.

Conclusions

The diversity of arsenite oxidisers does not significantly differ from two subsamples of a microbial biofilm that vary in arsenite concentrations. GM1 is the first psychrotolerant arsenite oxidiser to be isolated with the ability to grow below 10°C. This ability to grow at low temperatures could be harnessed for arsenic bioremediation in moderate to cold climates.
Unique features of the rice blast resistance Pish locus revealed by large scale retrotransposon-tagging
Authors: Takahashi Akira , Hayashi Nagao , Miyao Akio , Hirochika Hirohiko
Published: August 2010

Background

R gene-mediated resistance is one of the most effective mechanisms of immunity against pathogens in plants. To date some components that regulate the primary steps of plant immunity have been isolated, however, the molecular dissection of defense signaling downstream of the R proteins remains to be completed. In addition, R genes are known to be highly variable, however, the molecular mechanisms responsible for this variability remain obscure.

Results

To identify novel factors required for R gene-mediated resistance in rice, we used rice insertional mutant lines, induced by the endogenous retrotransposon Tos17, in a genetic screening involving the rice blast fungus Magnaporthe oryzae. We inoculated 41,119 mutant lines with the fungus using a high throughput procedure, and identified 86 mutant lines with diminished resistance. A genome analysis revealed that 72 of the 86 lines contained mutations in a gene encoding a nucleotide binding site (NBS) and leucine rich repeat (LRR) domain-containing (NBS-LRR) protein. A genetic complementation analysis and a pathogenesis assay demonstrated that this NBS-LRR gene encodes Pish, which confers resistance against races of M. oryzae containing avrPish. The other 14 lines have intact copies of the Pish gene, suggesting that they may contain mutations in the signaling components downstream of Pish. The genome analysis indicated that Pish and its neighboring three NBS-LRR genes are high similar to one another and are tandemly located. An in silico analysis of a Tos17 flanking sequence database revealed that this region is a "hot spot" for insertion. Intriguingly, the insertion sites are not distributed evenly among these four NBS-LRR genes, despite their similarity at the sequence and expression levels.

Conclusions

In this work we isolated the R gene Pish, and identified several other mutants involved in the signal transduction required for Pish-mediated resistance. These results indicate that our genetic approach is efficient and useful for unveiling novel aspects of defense signaling in rice. Furthermore, our data provide experimental evidence that R gene clusters have the potential to be highly preferred targets for transposable element insertions in plant genomes. Based on this finding, a possible mechanism underlying the high variability of R genes is discussed.
Dual role of nNOS in ischemic injury and preconditioning
Authors: Barua Anupama , Standen Nicholas B , Galiñanes Manuel
Published: August 2010

Background

Nitric oxide (NO) is cardioprotective and a mediator of ischemic preconditioning (IP). Endothelial nitric oxide synthase (eNOS) is protective against myocardial ischemic injury and a component of IP but the role and location of neuronal nitric oxide synthase (nNOS) remains unclear. Therefore, the aims of these studies were to: (i) investigate the role of nNOS in ischemia/reoxygenation-induced injury and IP, (ii) determine whether its effect is species-dependent, and (iii) elucidate the relationship of nNOS with mitoKATP channels and p38MAPK, two key components of IP transduction pathway.

Results

Ventricular myocardial slices from rats and wild and nNOS knockout mice, and right atrial myocardial slices from human were subjected to 90 min ischemia and 120 min reoxygenation (37°C). Specimens were randomized to receive various treatments (n = 6/group). Both the provision of exogenous NO and the inhibition of endogenous NO production significantly reduced tissue injury (creatine kinase release, cell necrosis and apoptosis), an effect that was species-independent. The cardioprotection seen with nNOS inhibition was as potent as that of IP, however, in nNOS knockout mice the cardioprotective effect of non-selective NOS (L-NAME) and selective nNOS inhibition and also that of IP was blocked while the benefit of exogenous NO remained intact. Additional studies revealed that the cardioprotection afforded by exogenous NO and by inhibition of nNOS were unaffected by the mitoKATP channel blocker 5-HD, although it was abrogated by p38MAPK blocker SB203580.

Conclusions

nNOS plays a dual role in ischemia/reoxygenation in that its presence is necessary to afford cardioprotection by IP and its inhibition reduces myocardial ischemic injury. The role of nNOS is species-independent and exerted downstream of the mitoKATP channels and upstream of p38MAPK.
Molecular characterization of Chikungunya virus isolates from clinical samples and adult Aedes albopictus mosquitoes emerged from larvae from Kerala, South India
Authors: Niyas Kudukkil P , Abraham Rachy , Unnikrishnan Ramakrishnan Nair , Mathew Thomas , Nair Sajith , Manakkadan Anoop , Issac Aneesh , Sreekumar Easwaran
Published: August 2010

Chikungunya virus (CHIKV), an arthritogenic alphavirus, is transmitted to humans by infected Aedes (Ae.) aegypti and Ae.albopictus mosquitoes. In the study, reverse-transcription PCR (RT PCR) and virus isolation detected CHIKV in patient samples and also in adult Ae.albopictus mosquitoes that was derived from larvae collected during a chikungunya (CHIK) outbreak in Kerala in 2009. The CHIKV strains involved in the outbreak were the East, Central and South African (ECSA) genotype that had the E1 A226V mutation. The viral strains from the mosquitoes and CHIK patients from the same area showed a close relationship based on phylogenetic analysis. Genetic characterization by partial sequencing of non-structural protein 2 (nsP2; 378 bp), envelope E1 (505 bp) and E2 (428 bp) identified one critical mutation in the E2 protein coding region of these CHIKV strains. This novel, non-conservative mutation, L210Q, consistently present in both human and mosquito-derived samples studied, was within the region of the E2 protein (amino acids E2 200-220) that determines mosquito cell infectivity in many alpha viruses. Our results show the involvement of Ae. albopictus in this outbreak in Kerala and appearance of CHIKV with novel genetic changes. Detection of virus in adult mosquitoes, emerged in the laboratory from larvae, also points to the possibility of transovarial transmission (TOT) of mutant CHIKV strains in mosquitoes.
Systems analysis of iron metabolism: the network of iron pools and fluxes
Authors: Lopes Tiago JS , Luganskaja Tatyana , Vujić Spasić Maja , Hentze Matthias W , Muckenthaler Martina U , Schümann Klaus , Reich Jens G
Published: August 2010

Background

Every cell of the mammalian organism needs iron as trace element in numerous oxido-reductive processes as well as for transport and storage of oxygen. The very versatility of ionic iron makes it a toxic entity which can catalyze the production of radicals that damage vital membranous and macromolecular assemblies in the cell. The mammalian organism maintains therefore a complex regulatory network of iron uptake, excretion and intra-body distribution. Intracellular regulation in different cell types is intertwined with a global hormonal signalling structure. Iron deficiency as well as excess of iron are frequent and serious human disorders. They can affect every cell, but also the organism as a whole.

Results

Here, we present a kinematic model of the dynamic system of iron pools and fluxes. It is based on ferrokinetic data and chemical measurements in C57BL6 wild-type mice maintained on iron-deficient, iron-adequate, or iron-loaded diet. The tracer iron levels in major tissues and organs (16 compartment) were followed for 28 days. The evaluation resulted in a whole-body model of fractional clearance rates. The analysis permits calculation of absolute flux rates in the steady-state, of iron distribution into different organs, of tracer-accessible pool sizes and of residence times of iron in the different compartments in response to three states of iron-repletion induced by the dietary regime.

Conclusions

This mathematical model presents a comprehensive physiological picture of mice under three different diets with varying iron contents. The quantitative results reflect systemic properties of iron metabolism: dynamic closedness, hierarchy of time scales, switch-over response and dynamics of iron storage in parenchymal organs.

Therefore, we could assess which parameters will change under dietary perturbations and study in quantitative terms when those changes take place.
The NRF2-mediated oxidative stress response pathway is associated with tumor cell resistance to arsenic trioxide across the NCI-60 panel
Authors: Liu Qian , Zhang Hao , Smeester Lisa , Zou Fei , Kesic Matt , Jaspers Ilona , Pi Jingbo , Fry Rebecca C
Published: August 2010

Background

Drinking water contaminated with inorganic arsenic is associated with increased risk for different types of cancer. Paradoxically, arsenic trioxide can also be used to induce remission in patients with acute promyelocytic leukemia (APL) with a success rate of approximately 80%. A comprehensive study examining the mechanisms and potential signaling pathways contributing to the anti-tumor properties of arsenic trioxide has not been carried out.

Methods

Here we applied a systems biology approach to identify gene biomarkers that underlie tumor cell responses to arsenic-induced cytotoxicity. The baseline gene expression levels of 14,500 well characterized human genes were associated with the GI50data of the NCI-60 tumor cell line panel from the developmental therapeutics program (DTP) database. Selected biomarkers were testedin vitrofor the ability to influence tumor susceptibility to arsenic trioxide.

Results

A significant association was found between the baseline expression levels of 209 human genes and the sensitivity of the tumor cell line panel upon exposure to arsenic trioxide. These genes were overlayed onto protein-protein network maps to identify transcriptional networks that modulate tumor cell responses to arsenic trioxide. The analysis revealed a significant enrichment for the oxidative stress response pathway mediated by nuclear factor erythroid 2-related factor 2 (NRF2) with high expression in arsenic resistant tumor cell lines. The role of the NRF2 pathway in protecting cells against arsenic-induced cell killing was validated in tumor cells using shRNA-mediated knock-down.

Conclusions

In this study, we show that the expression level of genes in the NRF2 pathway serve as potential gene biomarkers of tumor cell responses to arsenic trioxide. Importantly, we demonstrate that tumor cells that are deficient for NRF2 display increased sensitivity to arsenic trioxide. The results of our study will be useful in understanding the mechanism of arsenic-induced cytotoxicity in cells, as well as the increased applicability of arsenic trioxide as a chemotherapeutic agent in cancer treatment.
Two-dimensional simulation of Rayleigh waves with staggered sine/cosine transforms and variable grid spacing
Authors: Kosloff Dan , Carcione José M.
Published: August 2010

Simulation of Rayleigh waves requires high accuracy and an adequate spatial sampling at the surface. Discrete cosine and sine transforms are used to compute spatial derivatives along the direction perpendicular to the surface of the earth. Unlike the standard Fourier method, these transforms allow nonperiodic boundary conditions to be satisfied, in particular, the stress-free conditions at the surface. Because simulation of surface waves requires more points per minimum wavelength at the surface than simulation of body waves, the equispaced grid is not efficient. To overcome this problem, a grid compression is performed at the surface to obtain a denser spatial sampling. Grid size is minimal at the surface and increases with depth until reaching, at a relatively shallow depth, the grid points per wavelength required by the body waves. The stress-free boundary conditions are naturally handled by expanding the appropriate stress components in terms of the discrete sine transform. The wave equation is solved in the particle-velocity and stress formulation using a Runge-Kutta time integration and the convolutional PML (CPML) method to prevent reflections from the mesh boundaries. The simulations are very accurate for shallow sources and receivers and large offsets.
Nitric oxide in the control of luminescence from lantern shark (Etmopterus spinax) photophores
Authors: Claes Julien M. , Krönström Jenny , Holmgren Susanne , Mallefet Jérôme
Published: August 2010

Photophores (photogenic organs) of the lantern shark Etmopterus spinax are under hormonal control, with prolactin (PRL) and melatonin (MT) triggering the light emission. Differential sensitivity to these hormones in adult individuals suggests, however, that the luminescence of this shark is controlled by an additional mechanism. In this study, different techniques were used to investigate a potential modulator of E. spinax luminescence – nitric oxide (NO). NO synthase (NOS)-like immunoreactivity (IR) was found in the photocytes (photogenic cells) of the photophores. In addition, acetylated tubulin IR also supported the presence of nerves running through the photogenic tissue and innervating different structural elements of the photophores: photocytes, pigmented cells from the iris-like structure and lens cells. Pharmacological experiments confirmed a modulatory action of NO on the hormonally induced luminescence: NO donors sodium nitroprusside (SNP) and hydroxylamine decreased the time to reach the maximum amplitude (TLmax) of MT-induced luminescence while these substances decreased the maximum amplitude of PRL-induced luminescence (and also the TLmax in the case of SNP). The small impact of the NOS inhibitor l-NAME on hormonally induced luminescence suggests that NO is only produced on demand. The cGMP analogue 8BrcGMP mimicked the effects of NO donors suggesting that the effects of NO are mediated by cGMP.
Reliable detection of predator cues in afferent spike trains of a katydid under high background noise levels
Authors: Hartbauer Manfred , Radspieler Gerald , Römer Heiner
Published: August 2010

Katydid receivers face the problem of detecting behaviourally relevant predatory cues from echolocating bats in the same frequency domain as their own conspecific mating signals. We therefore tested the hypothesis that katydids are able to detect the presence of insectivorous bats in spike discharges at early stages of nervous processing in the auditory pathway by using the temporal details characteristic for responses to echolocation sequences. Spike activity was recorded from an identified nerve cell (omega neuron) under both laboratory and field conditions. In the laboratory, the preparation was stimulated with sequences of bat calls at different repetition rates typical for the guild of insectivorous bats, in the presence of background noise. The omega cell fired brief high-frequency bursts of action potentials in response to each bat sound pulse. Repetition rates of 18 and 24 Hz of these pulses resulted in a suppression of activity resulting from background noise, thus facilitating the detection of bat calls. The spike activity typical for responses to bat echolocation contrasts to responses to background noise, producing different distributions of inter-spike intervals. This allowed development of a ‘neuronal bat detector’ algorithm, optimized to detect responses to bats in afferent spike trains. The algorithm was applied to more than 24 hours of outdoor omega-recordings performed either at a rainforest clearing with high bat activity or in rainforest understory, where bat activity was low. In 95% of cases, the algorithm detected a bat reliably, even under high background noise, and correctly rejected responses when an electronic bat detector showed no response.
Application of the two-sample doubly labelled water method alters behaviour and affects estimates of energy expenditure in black-legged kittiwakes
Authors: Schultner Jannik , Welcker Jorg , Speakman John R. , Nordøy Erling S. , Gabrielsen Geir W.
Published: August 2010

Despite the widespread use of the doubly labelled water (DLW) method in energetic studies of free-ranging animals, effects of the method on study animals are rarely assessed. We studied behavioural effects of two alternative DLW protocols. During two consecutive breeding seasons, 42 parent black-legged kittiwakes received either the commonly used two-sample (TS) or the less invasive single-sample (SS) DLW treatment. A third group served as a non-treated control. We evaluated the effect of treatment with respect to the time birds took to return to their nest after treatment and recaptures, and the nest attendance during DLW measurement periods. We found that TS kittiwakes took on average 20 times longer to return to their nest than SS kittiwakes after initial treatment, and nest attendance was reduced by about 40% relative to control birds. In contrast, nest attendance did not differ between control and SS kittiwakes. Estimates of energy expenditure of SS kittiwakes exceeded those of TS kittiwakes by 15%. This difference was probably caused by TS birds remaining inactive for extended time periods while at sea. Our results demonstrate that the common assumption that the TS DLW method has little impact on the behaviour of study subjects is in some circumstances fallacious. Estimates of energy expenditure derived by the SS approach may thus more accurately reflect unbiased rates of energy expenditure. However, the choice of protocol may be a trade-off between their impact on behaviour, and hence accuracy, and their differences in precision. Adopting procedures that minimize the impact of TS protocols may be useful.
Switching attraction to inhibition: mating-induced reversed role of sex pheromone in an insect
Authors: Barrozo Romina B. , Gadenne Christophe , Anton Sylvia
Published: August 2010

In the moth, Agrotis ipsilon, newly mated males cease to be attracted to the female-produced sex pheromone, preventing them from re-mating until the next night, by which time they would have refilled their reproductive glands for a potential new ejaculate. The behavioural plasticity is accompanied by a decrease in neuron sensitivity within the primary olfactory centre, the antennal lobe (AL). However, it was not clear whether the lack of the sexually guided behaviour results from the absence of sex pheromone detection in the ALs, or if they ignore it in spite of detection, or if the sex pheromone itself inhibits attraction behaviour after mating. To test these hypotheses, we performed behavioural tests and intracellular recordings of AL neurons to non-pheromonal odours (flower volatiles), different doses of sex pheromone and their mixtures in virgin and newly mated males. Our results show that, although the behavioural and AL neuron responses to flower volatiles alone were similar between virgin and mated males, the behavioural response of mated males to flower odours was inhibited by adding pheromone doses above the detection threshold of central neurons. Moreover, we show that the sex pheromone becomes inhibitory by differential central processing: below a specific threshold, it is not detected within the AL; above this threshold, it becomes inhibitory, preventing newly mated males from responding even to plant odours. Mated male moths have thus evolved a strategy based on transient odour-selective central processing, which allows them to avoid the risk-taking, energy-consuming search for females and delay re-mating until the next night for a potential new ejaculate.
On the role of copepod antennae in the production of hydrodynamic force during hopping
Authors: Borazjani Iman , Sotiropoulos Fotis , Malkiel Edwin , Katz Joseph
Published: August 2010

We integrate high-resolution experimental observations of a freely hopping copepod with three-dimensional numerical simulations to investigate the role of the copepod antennae in production of hydrodynamic force during hopping. The experimental observations revealed a distinctive asymmetrical deformation of the antennae during the power and return strokes, which lead us to the hypothesis that the antennae are active contributors to the production of propulsive force with kinematics selected in nature in order to maximize net thrust. To examine the validity of this hypothesis we carried out numerical experiments using an anatomically realistic, tethered, virtual copepod, by prescribing two sets of antenna kinematics. In the first set, each antenna moves as a rigid, oar-like structure in a reversible manner, whereas in the second set, the antenna is made to move asymmetrically as a deformable structure as revealed by the experiments. The computed results show that for both cases the antennae are major contributors to the net thrust force during hopping, and the results also clearly demonstrate the significant hydrodynamic benefit in terms of thrust enhancement and drag reduction derived from the biologically realistic, asymmetric antenna motion. This finding is not surprising given the low local Reynolds number environment within which the antenna operates, and points to striking similarities between the copepod antenna motion and ciliary propulsion. Finally, the simulations provide the first glimpse into the complex, highly 3-D structure of copepod wakes.
Goal seeking in honeybees: matching of optic flow snapshots?
Authors: Dittmar Laura , Stürzl Wolfgang , Baird Emily , Boeddeker Norbert , Egelhaaf Martin
Published: August 2010

Visual landmarks guide humans and animals including insects to a goal location. Insects, with their miniature brains, have evolved a simple strategy to find their nests or profitable food sources; they approach a goal by finding a close match between the current view and a memorised retinotopic representation of the landmark constellation around the goal. Recent implementations of such a matching scheme use raw panoramic images (‘image matching’) and show that it is well suited to work on robots and even in natural environments. However, this matching scheme works only if relevant landmarks can be detected by their contrast and texture. Therefore, we tested how honeybees perform in localising a goal if the landmarks can hardly be distinguished from the background by such cues. We recorded the honeybees' flight behaviour with high-speed cameras and compared the search behaviour with computer simulations. We show that honeybees are able to use landmarks that have the same contrast and texture as the background and suggest that the bees use relative motion cues between the landmark and the background. These cues are generated on the eyes when the bee moves in a characteristic way in the vicinity of the landmarks. This extraordinary navigation performance can be explained by a matching scheme that includes snapshots based on optic flow amplitudes (‘optic flow matching’). This new matching scheme provides a robust strategy for navigation, as it depends primarily on the depth structure of the environment.
Zonation of heme synthesis enzymes in mouse liver and their regulation by β-catenin and Ha-ras
Authors: Braeuning Albert , Schwarz Michael
Published: August 2010

Cytochrome P450 (CYP) hemoproteins play an important role in hepatic biotransformation. Recently, β-catenin and Ha-ras signaling have been identified as players controlling transcription of various CYP genes in mouse liver. The aim of the present study was to analyze the role of β-catenin and Ha-ras in the regulation of heme synthesis. Heme synthesis-related gene expression was analyzed in normal liver, in transgenic mice expressing activated β-catenin or Ha-ras, and in hepatomas. Regulation of the aminolevulinate dehydratase promoter was studiedin vitro. Elevated expression of mRNAs and proteins involved in heme biosynthesis was linked to β-catenin activation in perivenous hepatocytes, in transgenic hepatocytes, and in hepatocellular tumors. Stimulation of the aminolevulinate dehydratase promoter by β-catenin was independent of the β-catenin/T-cell-specific transcription factor dimer. By contrast, activation of Ha-ras repressed heme synthesis-related gene expression. The present data suggest that β-catenin enhances the expression of both CYPs and heme synthesis-related genes, thus coordinating the availability of CYP apoprotein and its prosthetic group heme. The reciprocal regulation of heme synthesis by β-catenin and Ha-ras-dependent signaling supports our previous hypothesis that antagonistic action of these pathways plays a major role in the control of zonal gene expression in healthy mouse liver and aberrant expression patterns in hepatocellular tumors.
Amino acid residues modulating the activities of staphylococcal glutamyl endopeptidases
Authors: Ono Toshio , Ohara-Nemoto Yuko , Shimoyama Yu , Okawara Hisami , Kobayakawa Takeshi , Baba Tomomi T. , Kimura Shigenobu , Nemoto Takayuki K.
Published: August 2010

The glutamyl endopeptidase family of enzymes from staphylococci has been shown to be important virulence determinants of pathogenic family members, such asStaphylococcus aureus. Previous studies have identified the N-terminus and residues from positions 185–195 as potentially important regions that determine the activity of three members of the family. Cloning and sequencing of the new family members fromStaphylococcus caprae(GluScpr) andStaphylococcus cohnii(GluScoh) revealed that the N-terminal Val residue is maintained in all family members. Mutants of the GluV8 enzyme fromS. aureuswith altered N-terminal residues, including amino acids with similar properties, were inactive, indicating that the Val residue is specifically required at the N-terminus of this enzyme family in order for them to function correctly. Recombinant GluScpr was found to have peptidase activity intermediate between GluV8 and GluSE fromStaphylococcus epidermisand to be somewhat less specific in its substrate requirements than other family members. The 185–195 region was found to contribute to the activity of GluScpr, although other regions of the enzyme must also play a role in defining the activity. Our results strongly indicate the importance of the N-terminal and the 185–195 region in the activity of the glutamyl endopeptidases of staphylococci.
Multiplex analysis of mitochondrial DNA pathogenic and polymorphic sequence variants
Authors: Poole Jason C. , Procaccio Vincent , Brandon Martin C. , Merrick Greg , Wallace Douglas C.
Published: August 2010

The mitochondrial DNA (mtDNA) encompasses two classes of functionally important sequence variants: recent pathogenic mutations and ancient adaptive polymorphisms. To rapidly and cheaply evaluate both classes of single nucleotide variants (SNVs), we have developed an integrated system in which mtDNA SNVs are analyzed by multiplex primer extension using the SNaPshot system. A multiplex PCR amplification strategy was used to amplify the entire mtDNA, a computer program identifies optimal extension primers, and a complete global haplotyping system is also proposed. This system genotypes SNVs on multiplexed mtDNA PCR products or directly from enriched mtDNA samples and can quantify heteroplasmic variants down to 0.8% using a standard curve. With this system, we have developed assays for testing the common pathogenic mutations in four multiplex panels: two genotype the 13 most common pathogenic mtDNA mutations and two genotype the 10 most common Leber Hereditary Optic Neuropathy mutations along with haplogroups J and T. We use a hierarchal system of 140 SNVs to delineate the major global mtDNA haplogroups based on a global phylogenetic tree of coding region polymorphisms. This system should permit rapid and inexpensive genotyping of pathogenic and lineage-specific mtDNA SNVs by clinical and research laboratories.
Real-time polymerase chain reaction quantification of free DNA in serum of patients with polyps and colorectal cancers
Authors: Danese Elisa , Montagnana Martina , Minicozzi Anna Maria , De Matteis Giovanna , Scudo Giovanni , Salvagno Gian Luca , Cordiano Claudio , Lippi Giuseppe , Guidi Gian Cesare
Published: August 2010

Background: Colorectal cancer (CRC) is one of the most frequent causes of cancer related deaths worldwide. Recently, the use of cell-free DNA as diagnostic tools to identify cancer has been investigated. The aim of this work was to assess whether circulating DNA could be considered a useful marker for detection of early stage CRC and polyps.

Methods: A total of 118 patients with CRC were included in the study along with 49 patients with colorectal polyps and 26 control subjects. Cell-free DNA was quantified using a real-time TaqMan-polymerase chain reaction assay. Non-parametric tests (Mann-Whitney test and Spearman correlation) were utilized for statistical analysis.

Results: Serum DNA concentrations were significantly higher in CRC patients and patients with polyps (median value 105.0 ng/mL and 40.0 ng/mL) compared with controls (median value 14.0 ng/mL; p<0.05). Although carcinoembryonic antigen was above the cut-off in only 13/66 (19.7%) patients with early stage CRC, serum free DNA showed values above the threshold identified using receiver operator characteristic (ROC) curve analysis in 53/66 (80.3%) patients.

Conclusions: Our data confirm that serum DNA concentrations are significantly increased in CRC patients with early stage disease and in patients with polyps. This marker might be useful for identifying high-risk individuals.

Clin Chem Lab Med 2010;48:1665–8.
C-reactive protein and venous thromboembolism: causal or casual association?
Authors: Lippi Giuseppe , Favaloro Emmanuel J. , Montagnana Martina , Franchini Massimo
Published: August 2010

The plasma concentration of C-reactive protein (CRP), the first acute-phase protein to be identified, increases dramatically following tissue injury or inflammation. Although the physiological role of CRP is still not fully known, it has been suggested that concentrations might increase as part of the acute-phase response for facilitating non-specific immune functions, defense against bacterial pathogens, clearance of apoptotic and necrotic cells to prevent immunization against autoantigens and acceleration of the repair process. In agreement with the evidence that inflammation plays a pivotal role in the pathogenesis of atherosclerosis, CRP concentrations have been associated with cardiovascular disease, and measurement of CRP has therefore been proposed as a valuable aid to predict and stratify the risk of myocardial infarction and stroke. Recently, some clinical and biological evidence in support of the hypothesis that CRP might be also involved in the onset of venous thrombosis have emerged. Native and monomeric CRP exert several prothrombotic activities, including activation of blood coagulation, impairment of the endogenous fibrinolytic capacity, and stimulation or enhancement of platelet adhesiveness and responsiveness. Epidemiological investigations have also shown that CRP concentrations are associated with increased risk of venous thromboembolism and, even more interestingly, that statins might be effective in reducing the risk of this pathology. Although there is increasing emphasis that CRP might not only be a marker but also an active player in the development of venous thrombosis, further evidence is needed to establish which event comes first – thrombosis or inflammation.

Clin Chem Lab Med 2010;48:1693–701.
On Property (FA) for wreath products
Authors: Cornulier Yves , Kar Aditi
Published: August 2010

We characterize permutational wreath products with Property (FA). For instance, we show that the standard wreath product
Physical Rock Matrix Characterization: Structural and Mineralogical Heterogeneities in Granite
Authors: Voutilainen Mikko , Lamminmäki Suvi , Timonen Jussi , Siitari-kauppi Marja , Breitner Daniel
Published: August 2010

Evaluation of the transport and retardation properties of rock matrices that serve as host rock for nuclear waste repositories necessitates their thorough pore-space characterization. Relevant properties to be quantified include the diffusion depth and volume adjacent to water conducting features. The bulk values of these quantities are not sufficient due to the heterogeneity of mineral structure on the scale of the expected transport/interaction distances.
In this work the 3D pore structure of altered granite samples with porosities of 5 to 15%, taken next to water conducting fractures at 180 200 m depth in Sievi, Finland, was studied. Characterization of diffusion pathways and porosity were based on quantitative autoradiography of rock sections impregnated with C14-labelled polymethylmethacrylate (PMMA). Construction of 3D structure from PMMA autoradiographs was tested. The PMMA method was augmented by field emission scanning electron microscopy and energy-dispersive X-ray analyses (FESEM/EDAX) in order to study small pore-aperture regions in more detail and to identify the corresponding minerals. The 3D distribution of minerals and their abundances were determined by X-ray microtomography. Combining the mineral specific porosity found by the PMMA method with these distributions provided us with a 3D porosity distribution in the rock matrix.
Rapid-solidified Magnetostrictive Polycrystalline Strong-Textured Galfenol (Fe-Ga) Alloy and its Applications for Micro Gas-valve
Authors: Saito Chihiro , Tanaka Masamune , Okazaki Teiko , Furuya Yasubumi
Published: August 2010

The melt-spun, rapid solidified Galfenol (Fe-Gax, (17≤x≤19)) ribbon sample showed a clear angular dependency on magnetostriction and large magnetostriction (180-200ppm) and good ductility, higher strength etc..as compared with conventional bulk sample. This large magnetostriction is caused by non-precipitating of the ordered phases the release of considerable large internal stresses in as-spun ribbon as well as the remained [100] oriented strong textures after annealing. These are worthy for engineering application as a actuator/sensor devices, therefore, we will introduce the micro-valve which was designed as a device for micro gas-flow control. Bimorph-type FeGa/Ni with the opposite value (FeGa(+),Ni(-)) of magnetostriction coefficient. Large displacement of opposite type could be obtained and it degree and hysteresis curve changed depending the volume fraction of the composite actuator structure.
Rheology and Electrorheology of Nanorod-Loaded Liquid Crystalline Polymers
Authors: Cameron-Soto Ana Raquel , Aviles-Barreto Sonia Lizmar , Acevedo-Rullan Aldo
Published: August 2010

The effect of carbon nanotube concentration and dispersion on the rheology of liquid crystalline solutions of hydroxypropylcellulose (HPC) has been experimentally studied. The rheology of nanocomposites of HPC and multiwalled carbon nanotubes (MWCNT) in m-cresol was characterized in steady-state and transient dynamic tests. The rheology as particle loading increases shows a very distinct response in the magnitude and scaling of the steady-state viscosity, and the storage and loss modulus. The liquid crystalline phase was characterized by direct observations by reflected polarized light microscopy. Additionally, an electric-field effect was observed on the rheology of the HPC/MWCNT in m-cresol soft composites. The HPC in m-cresol matrix is non-responsive, thus the electrorheological effect is due to the presence of the carbon nanotubes. The mechanism for this effect is still uncertain, since it does not follow the scaling predicted by simple models for heterogeneous or homogeneous ER fluids.
Enhanced Vascular Endothelial Cell Function on Nanostructured Titanium Surface Features: The Role of Nano to Submicron Roughness
Authors: Lu Jing , Khang Dongwoo , Webster Thomas J.
Published: August 2010

To study the contribution of different surface feature properties in improving vascular endothelial cell adhesion, rationally designed nano/sub-micron patterns with various dimensions were created on titanium surfaces in this study. In vitro results indicated that endothelial cell adhesion was improved when the titanium pattern dimensions decreased into the nano-scale. Specifically, endothelial cells preferred to adhere on sub-micron and nano rough titanium substrates compared to flat titanium. Moreover, titanium with nano and sub-micron roughness and with the same chemistry as compared to flat titanium, had significantly greater surface energy. Thus, the present study indicated the strong potential of surface nanotopography and nano/sub-micron roughness for improving current vascular stent design.
A Novel Approach to Synthesis and Characterization of Biocompatible ZnO Nanoparticles
Authors: Nag N. , Doak J. , Gupta R. K. , Mishra S. , Kahol P. K. , Ghosh K. , Manivannan K.
Published: August 2010

Zinc Oxide nanoparticles (ZnO) being biocompatible and chemically stable have great potential for bio-medical applications that includes anti-bacterial and mold prevention, air ventilation and purification, water purification, self cleaning and photosynthesis, and disease detection. Also ZnO is a wide band gap semiconductor and exhibits piezoelectric and pyroelectric properties, which makes it a perfect candidate for building electrochemically coupled sensors and transducers. With all these unique properties, ZnO has the potential to be very important nanomaterial in material research area. Therefore, research, development, and production of ZnO nanoparticles would make notable contributions to the field of nanotechnology. In this paper we report a novel approach for the fabrication of ZnO nanoparticles suspension in deionized water at room temperature using pulsed laser deposition (PLD) technique. Particle size was controlled by the number of shots of the laser beam used. Characterization of the nanoparticles has been done using UV-Visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). UV-Visible study confirmed the existence of ZnO nanoparticles showing a peak at around 300 nm which is consistent with the absorption spectra of standard ZnO nanoparticles. Presence of ZnO was reconfirmed by the excitation and emission spectra obtained from fluorescence spectroscopy. The excitation and emission peaks were found at 305 nm and 410 nm respectively, strongly suggesting the characteristic peaks for ZnO nanoparticles. Transmission electron microscope (TEM) photographs established that we have successfully prepared ZnO nanoparticles suspension with particle size ranging from 6 nm to 90 nm.
A Facile, “Green” One – Step, Room Temperature Synthesis of a Series of monodispersed MSe(M = Cd or Zn) Water Dispersible Nanoparticles
Authors: Oluwafemi Oluwatobi S. , Revaprasadu Neerish
Published: August 2010

We herein report a facile, ‘green’ one- step synthesis of a series of monodispersed water-soluble selenide nanoparticles at room temperature. The capping ligands used include, cysteine, methionine, ascorbic acid and starch which function as agents of solubilisation, stabilization and conjugation sites for biomolecules. The synthetic approach involves the addition of an appropriate volume of selenide ion produced via the reduction of selenium powder in water to an aqueous solution containing the ligand- metal salt (MCl2 M = Zn or Cd). Optical spectroscopy shows that the particles are of high quality while the transmission electron microscopy (TEM) of the samples shows variation in shapes ranging from dots to rods of high and low aspect ratios.