bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparative performance of clustering procedures for mixture of qualitative and quantitative data – an application to black gram
Authors: Kumar Sarkar Rupam , Rao A. R. , Wahi S. D. , Bhat K. V.
Published: July 2011

Knowledge of the genetic diversity of germplasm of breeding material is invaluable in crop improvement programmes. Frequently, qualitative and quantitative data are used separately to assess genetic diversity of crop genotypes. While assessing diversity based on qualitative and quantitative traits separately, there may occur a problem when the degree of correspondence between the clusters formed does not agree with each other. This study compares five different procedures of clustering based on the criterion of weighted average of observed proportion of misclassification in black gram genotypes using qualitative, quantitative traits and mixture data. The INDOMIX- and PRINQUAL-based clustering procedures, i.e. INDOMIX and PRINQUAL methods in conjunction with the k-means clustering procedure, show better performance compared with other clustering procedures, followed by clustering based on either quantitative or qualitative data alone. The use of the INDOMIX- and PRINQUAL-based procedures can help breeders in capturing the variation present in both qualitative and quantitative trait data simultaneously and solving the problem of ambiguity over the degree of correspondence between clustering based on either qualitative or quantitative traits alone.
Persisting maximum Agulhas leakage during MIS 14 indicated by massive Ethmodiscus oozes in the subtropical South Atlantic
Authors: Rackebrandt Nick , Kuhnert Henning , Groeneveld Jeroen , Bickert Torsten
Published: July 2011

The glacial marine isotope stage 14 (MIS 14) appears in many climate records as an unusually warm glacial. During this period an almost monospecific, up to 1.5 m thick, laminated layer of the giant diatom Ethmodiscus rex has been deposited below the South Atlantic Subtropical Gyre. This oligotrophic region is today less favorable for diatom growth with sediments typically consisting of calcareous nannofossil oozes. We have reconstructed temperatures and the stable oxygen isotopic compositions of sea surface and thermocline water (δ18Ow) from planktonic foraminiferal (Globigerinoides ruber and Globorotalia inflata) Mg/Ca and stable oxygen isotopes to test whether perturbations in surface ocean conditions contributed to the deposition of the diatom layer at ∼530 kyr B.P. Temperatures and δ18Ow values reconstructed from this diatom ooze interval are highly variable, with maxima similar to interglacial values. Since the area of the Ethmodiscus oozes resembles the region where Agulhas rings are present, we interpret these hydrographic changes to reflect the varying influence of warm and saline water of Indian Ocean origin that entered the Subtropical Gyre trapped in Agulhas rings. The formation of the Ethmodiscus oozes is associated with a period of maximum Agulhas leakage and a maximum frequency of Agulhas ring formation caused by a termination‐type position of the Subtropical Front during the unusual warm MIS 14. The input of silica through the Agulhas rings enabled the shift in primary production from calcareous nannoplankton to diatoms, leading to the deposition of the massive diatom oozes.
Measurement of fluid flow generated by artificial cilia
Authors: Kokot Gašper , Vilfan Mojca , Osterman Natan , Vilfan Andrej , Kavčič Blaž , Poberaj Igor , Babič Dušan
Published: July 2011

We observed and measured the fluid flow that was generated by an artificial cilium. The cilium was composed of superparamagnetic microspheres, in which magnetic dipole moments were induced by an external magnetic field. The interaction between the dipole moments resulted in formation of long chains—cilia, and the same external magnetic field was also used to drive the cilia in a periodic manner. Asymmetric periodic motion of the cilium resulted in generation of fluid flow and net pumping of the surrounding fluid. The flow and pumping performance were closely monitored by introducing small fluorescent tracer particles into the system. By detecting their motion, the fluid flow around an individual cilium was mapped and the flow velocities measured. We confirm that symmetric periodic beating of one cilium results in vortical motion only, whereas asymmetry is required for additional translational motion. We determine the effect of asymmetry on the pumping performance of a cilium, verify the theoretically predicted optimal pumping conditions, and determine the fluid behaviour around a linear array of three neighbouring cilia. In this case, the contributions of neighbouring cilia enhance the maximal flow velocity compared with a single cilium and contribute to a more uniform translational flow above the surface.
Self-aligned fabrication of in-plane SiGe nanowires on rib-patterned Si (001) substrates
Authors: Chen G. , Springholz G. , Jantsch W. , Schäffler F.
Published: July 2011

SiGe heteroepitaxy on Si (001) substrates induces three-dimensional Stranski–Krastanow growth. In this work, in-plane nanowires were produced during the growth of Si0.8Ge0.2 onto rib-patterned Si (001) templates oriented in [010] direction. Atomic force microscopy reveals initially hut-shaped SiGe islands on the upper (001) area of the ribs form extended nanowires with lengths of up to 10 μm via coalescence and self-alignment to the rib direction. Finite element simulations show that these phenomena can be attributed to the minimization of the surface and strain energy density. This method provides a route towards devices based on in-plane SiGe nanowires.
Short-wavelength and three-dimensional instability evolution in National Ignition Facility ignition capsule designs
Authors: Clark D. S. , Haan S. W. , Cook A. W. , Edwards M. J. , Hammel B. A. , Koning J. M. , Marinak M. M.
Published: August 2011

Ignition capsule designs for the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 443, 2841 (2004)] have continued to evolve in light of improved physical data inputs, improving simulation techniques, and, most recently, experimental data from a growing number of NIF sub-ignition experiments. This paper summarizes a number of recent changes to the cryogenic capsule design and some of our latest techniques in simulating its performance. Specifically, recent experimental results indicated harder x-ray drive spectra in NIF hohlraums than were predicted and used in previous capsule optimization studies. To accommodate this harder drive spectrum, a series of high-resolution 2-D simulations, resolving Legendre mode numbers as high as 2000, were run and the germanium dopant concentration and ablator shell thicknesses re-optimized accordingly. Simultaneously, the possibility of cooperative or nonlinear interaction between neighboring ablator surface defects has motivated a series of fully 3-D simulations run with the massively parallel HYDRA code. These last simulations include perturbations seeded on all capsule interfaces and can use actual measured shell surfaces as initial conditions. 3-D simulations resolving Legendre modes up to 200 on large capsule sectors have run through ignition and burn, and higher resolution simulations resolving as high as mode 1200 have been run to benchmark high-resolution 2-D runs. Finally, highly resolved 3-D simulations have also been run of the jet-type perturbation caused by the fill tube fitted to the capsule. These 3-D simulations compare well with the more typical 2-D simulations used in assessing the fill tube’s impact on ignition. Coupled with the latest experimental inputs from NIF, our improving simulation capability yields a fuller and more accurate picture of NIF ignition capsule performance.
Rapid formation of size-controlled three dimensional hetero-cell aggregates using micro-rotation flow for spheroid study
Authors: Ota Hiroki , Kodama Taiga , Miki Norihisa
Published: July 2011

Spheroids that are formed from aggregated cells have enhanced biological function compared to individual cells. In particular, hetero-spheroids composed of different types of cells, such as hepatocytes and endothelial cells, express tissue specific functions at a high level, which is advantageous for more precise drug screening and biological research. In this study, we propose rapid formation of size-controlled three-dimensional hetero-cell aggregates consisting of hepatocytes and endothelial cells using micro-rotation flow. Based on previous data, these aggregates are expected to ultimately become hetero-spheroids. The hepatocytes are coated with collagen gel films less than 200 nm thick, which were experimentally verified to increase adhesion strength between hepatocytes and endothelial cells. Gel-coated hepatocytes and endothelial cells are collected in an array by micro-rotational flow, thereby forming hetero-cell aggregates within 2 min. This array allowed the size of the three-dimensional cell aggregates to be hydrodynamically controlled, with standard deviations of less than 19%, by varying the cell density of the medium without altering the device geometry. Endothelial cells were successfully and uniformly dispersed in the aggregates. The proposed microfluidic device, with its capability of rapidly forming size-controlled hetero-cell aggregates, will offer an efficient experimental platform for future hetero-spheroid study that will contribute to drug screening and regenerative medicine.
Energetic electron avalanches and mode transitions in planar inductively coupled radio-frequency driven plasmas operated in oxygen
Authors: Zaka-ul-Islam M. , Niemi K. , Gans T. , O'Connell D.
Published: July 2011

Space and phase resolved optical emission spectroscopic measurements reveal that in certain parameter regimes, inductively coupled radio-frequency driven plasmas exhibit three distinct operation modes. At low powers, the plasma operates as an alpha-mode capacitively coupled plasma driven through the dynamics of the plasma boundary sheath potential in front of the antenna. At high powers, the plasma operates in inductive mode sustained through induced electric fields due to the time varying currents and associated magnetic fields from the antenna. At intermediate powers, close to the often observed capacitive to inductive (E-H) transition regime, energetic electron avalanches are identified to play a significant role in plasma sustainment, similar to gamma-mode capacitively coupled plasmas. These energetic electrons traverse the whole plasma gap, potentially influencing plasma surface interactions as exploited in technological applications.
Synchronization based system identification of an extended excitable system
Authors: Berg S. , Luther S. , Parlitz U.
Published: July 2011

A basic state and parameter estimation scheme for an extended excitable system is presented, where time series from a spatial grid of sampling points are used to drive and synchronize corresponding model equations. Model parameters are estimated by minimizing the synchronization error. This estimation scheme is demonstrated using data from generic models of excitable media exhibiting spiral wave dynamics and chaotic spiral break-up that are implemented on a graphics processing unit.
The Casimir spectrum revisited
Authors: Herdeiro Carlos A. R. , Sampaio Marco O. P. , Santos Jaime E.
Published: July 2011

We examine the mathematical and physical significance of the spectral density σ(ω) introduced by Ford [Phys. Rev. D 38, 528 (1988)]10.1103/PhysRevD.38.528, defining the contribution of each frequency to the renormalised energy density of a quantum field. Firstly, by considering a simple example, we argue that σ(ω) is well defined, in the sense of being regulator independent, despite an apparently regulator dependent definition. We then suggest that σ(ω) is a spectral distribution, rather than a function, which only produces physically meaningful results when integrated over a sufficiently large range of frequencies and with a high energy smooth enough regulator. Moreover, σ(ω) is seen to be simply the difference between the bare spectral density and the spectral density of the reference background. This interpretation yields a simple “rule of thumb” to writing down a (formal) expression for σ(ω) as shown in an explicit example. Finally, by considering an example in which the sign of the Casimir force varies, we show that the spectrum carries no manifest information about this sign; it can only be inferred by integrating σ(ω).
Methyl groups at dielectric and metal surfaces studied by sum-frequency generation in co- and counter-propagating configurations
Authors: Jena Kailash C. , Hung Kuo-Kai , Schwantje Travis R. , Hore Dennis K.
Published: July 2011

The optimum experimental geometry for visible-infrared sum-frequency generation experiments depends rather sensitively on the molecules adsorbed at the surface, their orientation, and the nature of the adjacent bulk media. We consider the commonly encountered case of methyl groups situated at air–water, air–gold, and polymer–water interfaces. We provide expressions that may be used to determine the optimal visible and IR beam incident angles, considering the symmetric and antisymmetric modes separately and then together. The analysis is carried out for co-propagating (collinear and non-collinear geometries) and counter-propagating configurations. We first consider that one or more vibrational modes are of interest, and the goal is to study them quantitatively under a single polarization scheme; our results enable the user to set the beam angles for such an experiment. In the second case, molecular orientation information is desired, and so the calibrated response is required in all accessible polarization schemes for full characterization of the nonlinear susceptibility tensor.
A circular dielectric grating for vertical extraction of single quantum dot emission
Authors: Davanço M. , Rakher M. T. , Schuh D. , Badolato A. , Srinivasan K.
Published: July 2011

We demonstrate a nanostructure composed of partially etched annular trenches in a suspended GaAs membrane, designed for efficient and moderately broadband (≈5 nm) emission extraction from single InAs quantum dots. Simulations indicate that a dipole embedded in the nanostructure center radiates upward into free space with a nearly Gaussian far field, allowing a collection efficiency >80% with a high numerical aperture (NA = 0.7) optic and with ≈12× Purcell radiative rate enhancement. Fabricated devices exhibit a ≈10% photon collection efficiency with a NA = 0.42 objective, a 20× improvement over quantum dots in unpatterned GaAs. A fourfold exciton lifetime reduction indicates moderate Purcell enhancement.
Core-level positive-ion and negative-ion fragmentation of gaseous and condensed HCCl3 using synchrotron radiation
Authors: Lu K. T. , Chen J. M. , Lee J. M. , Haw S. C. , Liang Y. C. , Deng M. J.
Published: July 2011

We investigated the dissociation dynamics of positive-ion and negative-ion fragments of gaseous and condensed HCCl3 following photoexcitation of Cl 2p electrons to various resonances. Based on ab initio calculations at levels HF/cc-pVTZ and QCISD/6-311G*, the first doublet structures in Cl L-edge x-ray absorption spectrum of HCCl3 are assigned to transitions from the Cl (2P3/2,1/2) initial states to the 10a1* orbitals. The Cl 2p → 10a1* excitation of HCCl3 induces a significant enhancement of the Cl+ desorption yield in the condensed phase and a small increase in the HCCl+ yield in the gaseous phase. Based on the resonant photoemission of condensed HCCl3, excitations of Cl 2p electrons to valence orbitals decay predominantly via spectator Auger transitions. The kinetic energy distributions of Cl+ ion via the Cl 2p → 10a1* excitation are shifted to higher energy ∼0.2 eV and ∼0.1 eV relative to those via the Cl 2p → 10e* excitation and Cl 2p → shape resonance excitation, respectively. The enhancement of the yields of ionic fragments at specific core-excited resonance states is assisted by a strongly repulsive surface that is directly related to the spectator electrons localized in the antibonding orbitals. The Cl− anion is significantly reinforced in the vicinity of Cl 2p ionization threshold of gaseous HCCl3, mediated by photoelectron recapture through post-collision interaction.
Annual secondary production of two estuarine mysid species (Mysidacea: Mysidae) inhabiting an intermittently closed estuary, south-eastern New Zealand
Authors: Lill Adrian W. T. , Closs Gerard. P. , Savage Candida , Schallenberg Marc
Published: July 2011

Estimates of secondary production are essential to understanding how communities function. Estimates of secondary production for key species such as mysids are scarce, especially in estuarine environments. There are no estimates for mysid production in intermittently closed estuaries in the world, and no estimates for endemic New Zealand mysids. The current study presents length–mass models for two mysid species (Tenagomysis chiltoni Tattersall, 1923 and T. novae-zealandiae Thomson, 1900) from the south-eastern coast of the South Island, New Zealand. Kaikorai Lagoon, a small intermittently closed estuary, supported a large average annual biomass of T. novae-zealandiae (861.77 mg m–2) and T. chiltoni (971.90 mg m–2). The Hynes average-cohort method was used with length–mass models to estimate the annual production of breeding populations of T. chiltoni and T. novae-zealandiae collected over a year in parts of the Kaikorai Lagoon. Compared with similar temperate ecosystems worldwide, the studied ecosystem indicated high annual production (11 328.8 mg m–2 year–1 and 6585.2 mg m–2 year–1) and turnover rates (P : B) (13.16 and 6.78) for T. novae-zealandiae and T. chiltoni, respectively. High annual secondary production may be due to relatively stable hydrological and food conditions found in intermittently closed estuaries, leading to dense stable populations that are maintained through much of the year.
Avian cognition and social interaction
Authors: Pepperberg Irene M.
Published: July 2011

The study of animal behavior, and particularly avian behavior, has advanced significantly in the past 50 years. In the early 1960s, both ethologists and psychologists were likely to see birds as simple automatons, incapable of complex cognitive processing. Indeed, the term “avian cognition” was considered an oxymoron. Avian social interaction was also seen as based on rigid, if sometimes complicated, patterns. The possible effect of social interaction on cognition, or vice versa, was therefore something almost never discussed. Two paradigm shifts—one concerning animal cognition and one concerning social interaction—began to change perceptions in, respectively, the early 1970s and 1980s, but only more recently have researchers actively investigated how these two areas intersect in the study of avian behavior. The fruits of such intersection can be seen in the various papers for this special issue. I provide some brief background material before addressing the striking findings of current projects. In some cases, researchers have adapted early classic methods and in other cases have devised new paradigms, but in all instances have demonstrated avian capacities that were once thought to be the exclusive domain of humans or at least nonhuman primates.
Keywords: avian cognition; avian social learning; avian observational learning; avian communication
Social cognition and learning mechanisms
Authors: Daisley Jonathan N. , Rosa Salva Orsola , Regolin Lucia , Vallortigara Giorgio
Published: July 2011

In this paper we review the literature on social learning mechanisms in the domestic chick, focusing largely on work from our own laboratories. The domestic chicken is a social-living bird that searches for food in flocks, avoids predators by following warnings from other flock members, and forms (stable) social hierarchies. All of these behaviors develop throughout ontogeny, largely during the very early stages post-hatch. Newly hatched chicks appear to have predispositions to orient towards and to pay greatest attention to the biologically relevant characteristics of their immediate environment (i.e. to conspecifics: the mother bird and/or fellow hatchlings) from which they may subsequently learn. In addition, the chick has a lateralized brain; left and right hemispheres being specialized for certain behavioral functions and responses, and it appears that such behavioral lateralization is also transposed onto certain social learning situations, which will also be considered.
Keywords: social learning; social cognition; chick; brain asymmetry
Social learning mechanisms
Authors: Zentall Thomas R.
Published: July 2011

Social influence and social learning are important to the survival of many organisms, and certain forms of social learning also may have important implications for their underlying cognitive processes. The various forms of social influence and learning are discussed with special emphasis on the mechanisms that may be responsible for opaque imitation (the copying of a response that the observer cannot easily see when it produces the response). Three procedures are examined, the results of which may qualify as opaque imitation: the bidirectional control procedure, the two- action procedure, and the do-as-I-do procedure. Variables that appear to affect the emergence of opaque imitation are identified and other complex forms of response copying are discussed.
Keywords: bidirectional control procedure; contagion; emulation; imitation; local enhancement; object movement reenactment; observational conditioning; opaque imitation; social enhancement; social facilitation; social influence; social learning; stimulus enhancement; two action procedure
Can jackdaws (Corvus monedula) select individuals based on their ability to help?
Authors: von Bayern Auguste M.P. , Clayton Nicola S. , Emery Nathan J.
Published: July 2011

Knowing the individual skills and competences of one's group members may be important for deciding from whom to learn (social learning), with whom to collaborate and whom to follow. We investigated whether 12 jackdaws could select conspecifics based on their helping skills, which had been exhibited in a previous context. The birds were tested in a blocked-exit-situation, where they could choose between two conspecifics, one of which could be recruited inside. One conspecific had previously displayed the ability to open the exit door whilst the other individual lacked the skill. The subjects showed a significant preference for the skilled conspecific if they had previously directly benefited from this skill. If they had merely observed the skilled (and non-skilled) individual opening (or failing to open) the exit door, they did not preferably choose the skilled conspecific. Taken together, these results suggest that jackdaws are capable of assessing other individuals' competence under certain circumstances.
Developmental ecology
Authors: West Meredith , King Andrew , Kohn Gregory
Published: July 2011

In this article we provide a case history of the development of a communicative system in songbirds. In particular, we explore how brown-headed cowbirds, male and female, cooperate in the development and use of species-typical song. The goal is to show how social interactions between and within sexes create a platform for the production and perception of song. We consider six perspectives. First, we discuss the nature of the acoustic signal. Second, we look at the process of song learning. Third, we describe a specific song mechanism, social shaping. Fourth, we look at the more general developmental process of neophenogenesis. Fifth, we consider the developmental ecology for social learning. Finally, we describe how social networks measures can be used to capture the nature of social interactions as the engines of song learning. Taken as a whole, we argue that culturally transmitted behaviors structure social interactions that predict the acquisition of species' typical behaviors necessary for successful reproduction.
‘Face’ across historical cultures
Authors: Ruhi Şükriye , Kádár Dániel Z.
Published: July 2011

This paper investigates the use of the word ‘face’ in late nineteenth- and early twentieth-century Turkish and Chinese so as to trace the meaning of the concept in the two languages and cultures. The study describes the occurrence of the lexeme in five semantic/pragmatic domains in novels dating from the turn of the twentieth century, a period that corresponds to an acceleration in modernisation movements. Two conclusions are drawn from the comparison of face in Turkish and Chinese, and noteworthy similarities and differences are shown. The interpersonal and the emotional domains cover a wide usage area but form mirror images of each other in terms of the frequency of the tokens. Yet, the Chinese novels reveal more metapragmatic discourse on talk. This is interpreted as face forming a profound emic notion in Chinese culture, which encompasses both relational management and the social worth of the person, while the Turkish novels suggest that it is an “idiom” primarily employed for describing relational management style.
Evidencing similarity
Authors: Rappert Brian
Published: July 2011

Accusations that some purposefully manipulate information in order to create a favourable impression in others are commonplace in political life. The term ‘spin’ has emerged in recent decades as a versatile but ill-defined normative charge that signifies a lost fidelity. This article examines a prominent attempt to adjudicate on allegations of it in order to ask how such debates are collaboratively produced and sustained. The case study is the ‘Butler Inquiry’, an investigation established to determine whether the British government distorted intelligence about Iraqi weapons of mass destruction capabilities in the build up to the 2003 war. It is argued that the Inquiry and the subsequent debate about it is notable for two features: (i) the multiple and shifting orientations adopted to the standing of language; and (ii) the lack of regard in this dispute about likeness to how determinations of likeness should be argued — a kind of “a-resemblance resemblancing”. Through the multiple ways in which matters of similitude were resolved and deferred, treated as publicly demonstrated and beyond simple verification, rendered knowable and undecidable, the debate about the Butler Inquiry established the conditions for further charges of spin. The failure to attend to how claims about resemblance were being grounded limited the public debate as well as conceptions of political accountability.
Making analogy work in the public arena
Authors: Livnat Zohar
Published: July 2011

This paper discusses the Israeli newspaper coverage of a single event of considerable public significance in the Israeli-Palestinian context. A dominant analogy in the coverage that played various argumentative roles and its responses are analyzed. When trying to answer the question of how to respond to an analogy put forward by a participant in a communication, various methods available to the interlocutor are mentioned, two of which are shown to be rhetorically effective in this case: (1) acceptance of the analogy enables the interlocutor to expand and enrich it into new argumentative directions; (2) a mere rejection of an analogy, without explicitly pointing to specific deficiencies in it or offering an alternative analogy, is shown to be potentially effective when its power stems from the use of irony: Ironic utterances allow for the explicit mention of the analogy, while at the same time holding it up to ridicule, thereby causing the rival’s arguments to be indirectly rejected. This method of rejection is not discussed in the literature on analogy. The analysis demonstrates the ways in which a figurative analogy might be effective although there is no difficulty to attack and refute it. In a complex context such as the political arena, the pragmatic effectiveness may be more relevant than incoherence, thus an analogy is not necessarily judged according to normative criteria.
Justice is blind
Authors: Ritchie L. David
Published: July 2011

In this article I present a model of how metaphors are transformed and re-presented as narratives, how this process helps shape communicative interactions, and how it contributes to relevance effects and the generation of meaning, often by simultaneously affecting multiple cognitive contexts. I demonstrate the application of the model to samples of discourse from current research and show how it can contribute to understanding troubled communicative relationships and potentially to improving communication in situations of misunderstanding and conflict.
Microtubules follow septins’ guidelines
Authors: Short Ben
Published: July 2011

Septin filaments direct the reorganization of microtubules during epithelial polarization.
Rüdiger Klein: Reading the guideposts for axon guidance
Authors: Sedwick Caitlin
Published: July 2011

Klein uses genetically modified mice to study how axons find the right targets to innervate.
High-resolution mapping reveals topologically distinct cellular pools of phosphatidylserine
Authors: Fairn Gregory D. , Schieber Nicole L. , Ariotti Nicholas , Murphy Samantha , Kuerschner Lars , Webb Richard I. , Grinstein Sergio , Parton Robert G.
Published: July 2011

Phosphatidylserine (PS) plays a central role in cell signaling and in the biosynthesis of other lipids. To date, however, the subcellular distribution and transmembrane topology of this crucial phospholipid remain ill-defined. We transfected cells with a GFP-tagged C2 domain of lactadherin to detect by light and electron microscopy PS exposed on the cytosolic leaflet of the plasmalemma and organellar membranes. Cytoplasmically exposed PS was found to be clustered on the plasma membrane, and to be associated with caveolae, the trans-Golgi network, and endocytic organelles including intraluminal vesicles of multivesicular endosomes. This labeling pattern was compared with the total cellular distribution of PS as visualized using a novel on-section technique. These complementary methods revealed PS in the interior of the ER, Golgi complex, and mitochondria. These results indicate that PS in the lumenal monolayer of the ER and Golgi complex becomes exposed cytosolically at the trans-Golgi network. Transmembrane flipping of PS may contribute to the exit of cargo from the Golgi complex.
Thiazolidinedione insulin sensitizers alter lipid bilayer properties and voltage-dependent sodium channel function: implications for drug discovery
Authors: Rusinova Radda , Herold Karl F. , Sanford R. Lea , Greathouse Denise V. , Hemmings Hugh C. , Andersen Olaf S.
Published: July 2011

The thiazolidinediones (TZDs) are used in the treatment of diabetes mellitus type 2. Their canonical effects are mediated by activation of the peroxisome proliferator–activated receptor γ (PPARγ) transcription factor. In addition to effects mediated by gene activation, the TZDs cause acute, transcription-independent changes in various membrane transport processes, including glucose transport, and they alter the function of a diverse group of membrane proteins, including ion channels. The basis for these off-target effects is unknown, but the TZDs are hydrophobic/amphiphilic and adsorb to the bilayer–water interface, which will alter bilayer properties, meaning that the TZDs may alter membrane protein function by bilayer-mediated mechanisms. We therefore explored whether the TZDs alter lipid bilayer properties sufficiently to be sensed by bilayer-spanning proteins, using gramicidin A (gA) channels as probes. The TZDs altered bilayer elastic properties with potencies that did not correlate with their affinity for PPARγ. At concentrations where they altered gA channel function, they also altered the function of voltage-dependent sodium channels, producing a prepulse-dependent current inhibition and hyperpolarizing shift in the steady-state inactivation curve. The shifts in the inactivation curve produced by the TZDs and other amphiphiles can be superimposed by plotting them as a function of the changes in gA channel lifetimes. The TZDs’ partition coefficients into lipid bilayers were measured using isothermal titration calorimetry. The most potent bilayer modifier, troglitazone, alters bilayer properties at clinically relevant free concentrations; the least potent bilayer modifiers, pioglitazone and rosiglitazone, do not. Unlike other TZDs tested, ciglitazone behaves like a hydrophobic anion and alters the gA monomer–dimer equilibrium by more than one mechanism. Our results provide a possible mechanism for some off-target effects of an important group of drugs, and underscore the importance of exploring bilayer effects of candidate drugs early in drug development.
D4cpv-calsequestrin: a sensitive ratiometric biosensor accurately targeted to the calcium store of skeletal muscle
Authors: Sztretye Monika , Yi Jianxun , Figueroa Lourdes , Zhou Jingsong , Royer Leandro , Ríos Eduardo
Published: July 2011

Current fluorescent monitors of free [Ca2+] in the sarcoplasmic reticulum (SR) of skeletal muscle cells are of limited quantitative value. They provide either a nonratio signal that is difficult to calibrate and is not specific or, in the case of Forster resonant energy transfer (FRET) biosensors, a signal of small dynamic range, which may be degraded further by imperfect targeting and interference from endogenous ligands of calsequestrin. We describe a novel tool that uses the cameleon D4cpv, which has a greater dynamic range and lower susceptibility to endogenous ligands than earlier cameleons. D4cpv was targeted to the SR by fusion with the cDNA of calsequestrin 1 or a variant that binds less Ca2+. “D4cpv-Casq1,” expressed in adult mouse at concentrations up to 22 µmole/liter of muscle cell, displayed the accurate targeting of calsequestrin and stayed inside cells after permeabilization of surface and t system membranes, which confirmed its strict targeting. FRET ratio changes of D4cpv-Casq1 were calibrated inside cells, with an effective KD of 222 µM and a dynamic range [(Rmax − Rmin)/Rmin] of 2.5, which are improvements over comparable sensors. Both the maximal ratio, Rmax, and its resting value were slightly lower in areas of high expression, a variation that was inversely correlated to distance from the sites of protein synthesis. The average [Ca2+]SR in 74 viable cells at rest was 416 µM. The distribution of individual ratio values was Gaussian, but that of the calculated [Ca2+]SR was skewed, with a tail of very large values, up to 6 mM. Model calculations reproduce this skewness as the consequence of quantifiably small variations in biosensor performance. Local variability, a perceived weakness of biosensors, thus becomes quantifiable. It is demonstrably small in D4cpv. D4cpv-Casq1 therefore provides substantial improvements in sensitivity, specificity, and reproducibility over existing monitors of SR free Ca2+ concentration.
R1 in the Shaker S4 occupies the gating charge transfer center in the resting state
Authors: Lin Meng-chin A. , Hsieh Jui-Yi , Mock Allan F. , Papazian Diane M.
Published: July 2011

During voltage-dependent activation in Shaker channels, four arginine residues in the S4 segment (R1–R4) cross the transmembrane electric field. It has been proposed that R1–R4 movement is facilitated by a “gating charge transfer center” comprising a phenylalanine (F290) in S2 plus two acidic residues, one each in S2 and S3. According to this proposal, R1 occupies the charge transfer center in the resting state, defined as the conformation in which S4 is maximally retracted toward the cytoplasm. However, other evidence suggests that R1 is located extracellular to the charge transfer center, near I287 in S2, in the resting state. To investigate the resting position of R1, we mutated I287 to histidine (I287H), paired it with histidine mutations of key voltage sensor residues, and determined the effect of extracellular Zn2+ on channel activity. In I287H+R1H, Zn2+ generated a slow component of activation with a maximum amplitude (Aslow,max) of ∼56%, indicating that only a fraction of voltage sensors can bind Zn2+ at a holding potential of −80 mV. Aslow,max decreased after applying either depolarizing or hyperpolarizing prepulses from −80 mV. The decline of Aslow,max after negative prepulses indicates that R1 moves inward to abolish ion binding, going beyond the point where reorientation of the I287H and R1H side chains would reestablish a binding site. These data support the proposal that R1 occupies the charge transfer center upon hyperpolarization. Consistent with this, pairing I287H with A359H in the S3–S4 loop generated a Zn2+-binding site. At saturating concentrations, Aslow,max reached 100%, indicating that Zn2+ traps the I287H+A359H voltage sensor in an absorbing conformation. Transferring I287H+A359H into a mutant background that stabilizes the resting state significantly enhanced Zn2+ binding at −80 mV. Our results strongly support the conclusion that R1 occupies the gating charge transfer center in the resting conformation.
Discrimination of wild and farmed Atlantic cod (Gadus morhua) based on morphology and scale-circuli pattern
Authors: Uglem Ingebrigt , Berg Marius , Varne Rebecca , Nilsen Rune , Mork Jarle , Bjørn Pål Arne
Published: July 2011

Uglem, I., Berg, M., Varne, R., Nilsen, R., Mork, J., and Bjørn, P. A. 2011. Discrimination of wild and farmed Atlantic cod (Gadus morhua) based on morphology and scale-circuli pattern. – ICES Journal of Marine Science, 68: 1928–1936. To evaluate the spatio–temporal distribution and ecological impacts of escaped farmed Atlantic cod (Gadus morhua), it is necessary that escapees can be traced in the wild. To do this, simple, reliable, and fast methods for determining the origin of cod are required. The aim of this proof-of-concept study was to evaluate whether simple analyses of scales and body morphology can distinguish between wild and farmed cod. Digital images of fish and scales from adult cod from two farms, and wild cod caught near these farms, were analysed by computer-based image analyses. By combining mean breadth of circuli and length-adjusted scale radius in a discriminant analysis, 86 and 80% of wild and farmed fish, respectively, were correctly classified. Moreover, using three simple morphometric measures representing dorsal fin size, neck curvature, and length of lower jaw, 100 and 95% of wild and farmed cod, respectively, were classified correctly. To validate these discrimination methods further, an expanded analysis of additional farmed and wild cod populations is required. The results pave the way for the development of a reliable and standardized methodology for classification of the origin of cod caught in the wild.
Attitude control system for the nano‐astrometry satellite “Nano‐JASMINE”
Authors: Inamori Takaya , Sako Nobutada , Nakasuka Shinichi
Published: July 2011

Purpose

This paper aims to present an attitude determination and control system for a nano‐astrometry satellite which requires precise angular rate control. Focus of the research is methods to achieve the requirement.

Design/methodology/approach

In order to obtain astrometry data, the satellite attitude should be controlled to an accuracy of 0.05°. Furthermore, attitude spin rate must be controlled to an accuracy of 4×10−7 rad/s during observation. In this paper the following unique ideas to achieve these requirements are introduced: magnetic disturbance compensation and rate estimation using star blurred images.

Findings

This paper presents the feasibility of a high accurate attitude control system in nano‐ and micro‐satellite missions.

Practical implications

This paper presents a possibility of the application of nano‐satellites to remote‐sensing and astronomy mission, which requires accurate attitude control.

Originality/value

Originalities of the paper are the methods to achieve the high accurate attitude control: magnetic disturbance compensation and angular rate estimation using star images.
Effect of austempering temperature and time on corrosion behaviour of ductile iron in chloride and acidic media
Authors: Afolabi A.S.
Published: July 2011

Purpose

The aim of this paper is to study the effect of heat treatment temperature and time on the corrosion behavior of ductile iron in 0.5 M NaCl and 0.5 M H2SO4.

Design/methodology/approach

Ductile iron samples of known composition were austenized at temperatures 800°C and 850°C, and austempered at 300°C and 350°C for periods of 30, 45 and 60 min to convert them to austempered ductile iron (ADI). The corrosion behavior of these ADI samples in 0.5 M NaCl and H2SO4 was measured using the conventional weight loss method. The metallographic examination of the samples was carried out to study the morphology of their corroded surfaces.

Findings

Ductile iron is susceptible to corrosion in both acidic and chloride media, while attack by acid media is mainly at the grain boundaries, that from the chloride is pitting. The corrosion behavior of the material is affected by the compositional structures of the materials as well as the austempering temperature and time it was subjected to.

Practical implications

Ductile iron has the potential to replace costlier materials in many engineering and structural applications.

Originality/value

The results revealed that the corrosion of ADI in both acidic and chloride media were strongly dependent on the structure of the material, which in turn was affected by the austempering temperature and time.
Effect of carbon dioxide on corrosion of tubular steel in high hydrogen sulfide and carbon dioxide environments
Authors: Deng Hongda , Li Chunfu , Cao Xianlong
Published: July 2011

Purpose

The present work primarily aims to study the corrosion characterization of tubular steel API‐P110 in high H2S containing solution with or without CO2.

Design/methodology/approach

Corrosion behaviors of steel in buffered solutions containing 50 percent H2S and various levels of CO2 concentration were investigated via weight‐loss method, SEM and EDS. The effects of CO2 on corrosion occurred on the metal were analyzed by electrochemical techniques.

Findings

Corrosion rates of steel decreased as the CO2 content in H2S/CO2 solution increased. It was observed for the tubular steel to experience an increase in corrosion rate at concentrations 17 percent CO2 or 34 percent CO2 in 50 percent H2S while when further increasing concentration of CO2 to 50 percent the corrosion rate decreases. Increased CO2 content in H2S/CO2 led to fewer anions desorbing and fewer reactants adsorbing, e.g. H+, H2CO3. As a result, cathodic reaction rate decreased and the amount of hydrogen absorbed decreased.

Originality/value

The experimental results showed that corrosion alleviated when increasing CO2 content in high H2S and CO2 containing environment.
Effect of frying, baking and storage conditions on resistant starch content of foods
Authors: Singh Yadav Baljeet
Published: July 2011

Purpose

The present study aims to understand the effect of baking, frying and storage conditions on resistant starch (RS) content of commonly used poor man's foods like potato, sweet potato and bread.

Design/methodology/approach

The effect of frying (shallow and deep frying) on RS was studied in pressure‐cooked potato and sweet potato. The baking conditions used for white wheat bread were 200°C‐35 min, 150°C‐12 h, and 120°C‐20 h. To study the effect of baking time at a specific temperature (200°C), the bread was baked for 15, 25, 35 and 45 min. The bread baked for 25 min at 200°C was stored at ambient conditions for 24, 48, 72 and 96 h. Tubers were stored at 4 and 25°C for 12 h and 24 h at each temperature.

Findings

Frying resulted in a reduction of 28.0 and 32.0 percent in RS content of potato and sweet potato respectively, with deep‐frying showing a more pronounced effect. The RS content of bread baked for 24 h at 120°C was found to be higher (4.20 percent) than that of bread baked at a higher temperature of 200°C and 150°C for 35 min and 12 h respectively. Increase in baking time from 15 to 45 min at 200° C also increased the RS content of bread from 2.13 percent to 3.18 percent. Storage resulted in an increase in the RS content of bread and tubers. Refrigeration storage had a more pronounced effect on the RS content of pressure‐cooked tubers.

Originality/value

This information on poor man's foods can be exploited to process and store the foods targeted to be used by the special category of persons, as varied processing conditions for these foods can be employed producing lower or higher RS content desirable for undernourished or diabetic persons respectively.
Fast food and fast games
Authors: Cronin James M. , McCarthy Mary B.
Published: July 2011

Purpose

The purpose of this paper is to understand how food is used to create identity and community for gamers during core rituals. These meanings are to be explored within the broader context of subcultural experience in an investigation of the motives and the self‐concept dynamics underlying this symbolic consumer behaviour.

Design/methodology/approach

This paper uses an interpretive research strategy and adopts a multi‐method ethnographic approach that includes: netnography: multiple, in‐depth, ethnographic interviews; and prolonged participant observation. Interview informants are young Irish subcultural members aged between 18 and 23. Data analysis proceeds according to a constant comparative method.

Findings

The findings suggest that the social gaming ritual, when intersected with food, is closely linked to issues of identity, community, fantasy and escape, gustatory rebellion and prolonged hedonism. Commensality during the core social gaming ritual contributes to a sense of communitas, while the “junk” nature of the shared food products helps to manufacture the hedonism of the event. The social ritual then is sovereign and bound by its own subcultural parameters, which oppose mainstream culture's norms and dietary regulations. From its role in helping to create a Utopian and rebellious experience, food is then leveraged as part of the gamers' collective identity. Practitioner implications of the results are discussed.

Originality/value

This paper investigates contemporary food consumption behaviour within a postmodern community. The main contribution pertains to providing an insight into a previously neglected group of food consumers.
Determination and comparison of the total polyphenol contents of fresh and commercial fruit juices
Authors: Mahdavi Reza , Nikniaz Zeinab , Rafraf Maryam , Jouyban Abolghasem
Published: July 2011

Purpose

This paper aims to study the importance of polyphenols in human health and, based on recommendations on the replacement of carbonated drinks with nutritious beverages, like fruit juices, seeks to compare the polyphenol contents of natural and commercial juices.

Design/methodology/approach

The total polypheol content of 39 fresh and 159 commercial (100 percent and less than 50 percent) fruit juices was analyzed by the terbium sensitized fluorescence method. The ANOVA with Tukey post hoc test, and also an independent t‐test, were used for statistical analyses.

Findings

The mean polyphenol contents of fresh juices were significantly (p<0.001) higher than those of 100 percent commercials (5.34±2.7 vs 3.28±0.86 mg/l). In fresh juices the concentration ranged from 1.06±0.08 (pineapple) to 10.14±0.07 (sour cherry) mg QE/100 ml, while in 100 percent commercial juices the range was from 2.37±0.05 (orange) to 5.34±0.4 (pomegranate) mg QE/100 ml, and in <50 percent commercial juices they ranged from 1.04±0.7 (red grape) to 2.21±0.07 (white grape) mg QE/100 ml. The polyphenol contents of dark juices, in both fresh and commercial products, were significantly higher than others (p<0.001) and most fresh fruit juices possessed higher amounts of polyphenol than commercial ones. Although various juices differed in the quantity of total polyphenol, they can be considered as a good source of functional beverage.

Originality/value

This paper provides information about the polyphenol content of fresh and commercial (100 percent and <50 percent) fruit juices. To the best of the authors' knowledge, there have been no articles which aim to compare the polyphenol content of Iranian fresh and commercial fruit juices. For analysing the polyphenol contents, the newly developed terbium sensitized fluorescence method was used, and also the applicability of this new method was compared with the commonly used Folin‐Ciocalteau method.