bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular origin of the difference in the HOH bend of the IR spectra between liquid water and ice
Authors: Imoto Sho , Xantheas Sotiris S. , Saito Shinji
Published: February 2013

The intensity of the HOH bend in the infrared (IR) spectrum of ice is significantly smaller than the corresponding one in liquid water. This difference in the IR intensities of the HOH bend in the two systems is investigated using Molecular Dynamics (MD) simulations with the flexible, polarizable, ab initio based TTM3-F model for water, a potential that correctly reproduces the experimentally observed increase of the HOH angle in liquid water and ice from the water monomer value. We have identified two factors that are responsible for the difference in the intensity of the HOH bend in liquid water and ice: (i) the decrease of the intensity of the HOH bend in ice caused by the strong anti-correlation between the permanent dipole moment of a molecule and the induced dipole moment of neighboring hydrogen bond acceptor molecules, and (ii) the weakening of this anti-correlation by the disordered hydrogen bond network in liquid water. The presence of the anti-correlation in ice is further confirmed by ab initio electronic structure calculations of water pentamer clusters extracted from the trajectories of the MD simulations with the TTM3-F potential for ice and liquid water.
Very large magnetoresistance and spin state transition in Ba-doped cobaltites
Authors: Troyanchuk I. O. , Bushinsky M. V. , Nikitin A. V. , Lobanovsky L. S. , Balagurov A. M. , Sikolenko V. , Efimov V. , Sheptyakov D. V.
Published: February 2013

Structural, magnetization, and magnetotransport measurements have been performed for anion deficient La0.5Ba0.5Co1−xFexO3−δ (x≤0.4) and La1−yBayCoO3−δ (0.5≤y≤0.6) perovskites. It has been found that the iron doped compositions with x≤0.23 are predominantly ferromagnetic. The Curie point and magnetization are slightly larger in insulating phase (x = 0.1) than in metallic one (x = 0.05). Magnetoresistance ratio rises with lowering temperature and increasing iron content reaching three orders of magnitude in predominantly antiferromagnetic state (x≥0.25). The rise of the barium content in La1−yBayCoO3−δ series above y = 0.5 leads to stabilization of antiferromagnetic phase and strong enhancement of the magnetoresistance. Antiferromagnetic ordering is accompanied by increase in resistivity. The lack of the low field intergrain magnetoresistance is in agreement with a weak spin polarization of the charge carriers. Magnetoresistance is associated with antiferromagnet–ferromagnet (from mixed high/low into intermediate spin state) transition induced by magnetic field. It is suggested that ferromagnetism is originated from superexchange interaction via oxygen.
Ecological optimization for generalized irreversible macro/nano thermosize engine
Authors: Wang Hao , Wu Guoxing
Published: February 2013

An irreversible macro/nano thermosize engine cycle model is established, in which the influence of the thermal resistances, heat leakage and the time of the regenerative processes are taken into account. Expressions for several important performance parameters, such as the power output (P), the efficiency (η), the entropy generation rate (σ), and the ecological function (E) are derived. The influence of heat leakage and the time of the regenerative processes (γ) on the ecological performance of the engine are discussed. The optimal regions of the ecological function, the power output, and the efficiency are determined and evaluated. Furthermore, some important parameter relations of the engine are revealed and discussed in detail. The results obtained here have general significance and will be helpful to deeply understand the performance of a macro/nano thermosize engine.
Complex magnetic phase separation induced by Li-doping in multiferroic CaBaCo4O7
Authors: Motin Seikh Md. , Sarkar Tapati , Pralong V. , Caignaert V. , Raveau B.
Published: February 2013

The doping of lithium at the cobalt sites in the multiferroic orthorhombic cobaltite CaBaCo4O7 has been investigated. The oxides CaBaCo4-2xLixGaxO7 and CaBaCo4-xLixO7 keep the same polar space group as the parent phase. In contrast, they show a spectacular decrease of their ferrimagnetic properties for very low doping levels (0 < x ≤ 0.10), with the appearance of antiferromagnetism below TN ∼ 80 K and magnetic frustration at around Tf ∼ 20 K, which should have a great impact upon multiferroism in this system. This behavior is different from that of the Ga-doped phases CaBaCo4-xGaxO7, but remarkably similar to that of the Zn-doped phases CaBaCo4-xZnxO7. The actual role of the valence of the diamagnetic cation, Li+ is interpreted from its ability to sit in the Co2+ zig-zag chain, breaking the ferromagnetism along those chains in both series of oxides. Importantly, the Li-doping in CaBaCo4-xLixO7 oxides, introduces an excess Co3+ with respect to the other two series, CaBaCo4-xZnxO7 and CaBaCo4-2xLixGaxO7. This additional Co3+ is thought to be at the origin of the complex magnetic phase separation and especially of new magnetic interactions that appear around 52 K in competition with magnetic frustration and antiferromagnetism.
High-pressure Raman scattering of CdO thin films grown by metal-organic vapor phase epitaxy
Authors: Oliva R. , Ibáñez J. , Artús L. , Cuscó R. , Zúñiga-Pérez J. , Muñoz-Sanjosé V.
Published: February 2013

We have performed Raman-scattering measurements under high hydrostatic pressure on CdO thin films grown by metal-organic vapor phase epitaxy on sapphire substrates. The pressure dependence of the second-order Raman bands is discussed in terms of ab initio lattice-dynamical calculations, which allow us to obtain mode Grüneisen parameters for the zone-center TO and LO modes of CdO. Our experiments and calculations suggest that at low pressures (<4 GPa) the Raman spectra are dominated by second-order modes, while at higher pressures (>4 GPa) the spectra mainly display contributions from disorder-activated first-order modes.
Biexciton energies in concentric double quantum rings
Authors: Wang Ning , Liu De , Kong Xiaojun
Published: February 2013

The energies of biexciton confined in one-dimensional concentric double quantum rings are studied using an exact diagonalization approach. An external magnetic field perpendicular to the ring plane is also included. The energies of L = 0 and L≠0 states of the concentric double quantum rings are calculated as functions of the ring radii and the intensity of the external magnetic field. We explore the effects of the Coulomb electron-hole correlation and of the magnetic field confinement for several ring distances and total angular momentum combinations. It is found that when the inner ring radius is very small (less than about 4 nm) the charges are distributed in both of the rings. However, if the inner ring is large, all carriers tend to localize in the inner ring. The angular momentum of the ground state depends on the magnitude of the magnetic field as well as on the distribution of particles in the rings. Likewise, the dependence of the energy on the angular momentum is different for a strong magnetic field than for a weak magnetic field.
Programmable ZnO nanowire transistors using switchable polarization of ferroelectric liquid crystal
Authors: Hong Woong-Ki , Inn Sohn Jung , Cha SeungNam , Min Kim Jong , Park Jong-Bae , Seok Choi Su , Coles Harry J. , Welland Mark E.
Published: February 2013

We demonstrate modulations of electrical conductance and hysteresis behavior in ZnO nanowire transistors via electrically polarized switching of ferroelectric liquid crystal (FLC). After coating a nanowire channel in the transistors with FLCs, we observed large increases in channel conductance and hysteresis width, and a strong dependence of hysteresis loops on the polarization states associated with the orientation of electric dipole moments along the direction of the gate electric field. Furthermore, the reversible switching and retention characteristics provide the feasibility of creating a hybrid system with switch and memory functions.
Optical contrast and laser-induced phase transition in GeCu2Te3 thin film
Authors: Saito Yuta , Sutou Yuji , Koike Junichi
Published: February 2013

Fast crystallization and low power amorphization are essential to achieve rapid data recording and low power consumption in phase-change memory. This work investigated the laser-induced phase transition behaviors of GeCu2Te3 film based on the reflectance of amorphous and crystalline states. The GeCu2Te3 film showed a reflectance decrease upon crystallization, which was the opposite behavior in Ge2Sb2Te5 film. The crystallization starting time of the as-deposited GeCu2Te3 film was as fast as that of the as-deposited Ge2Sb2Te5 film. Furthermore, the GeCu2Te3 crystalline film was found to be reamorphized by laser irradiation at lower power and shorter pulse width than the Ge2Sb2Te5.
Embedded mask patterning: A nanopatterning process to fabricate FePt magnetic media
Authors: Wang Hao , Zhao Haibao , Quarterman P. , Wang Jian-Ping
Published: February 2013

A nanopatterning process, named as the embedded mask patterning, was proposed and experimentally demonstrated based on the FePt recording media. A granular mask layer was deposited on top of a FePt continuous film. The granular pattern of the mask was then transferred down to FePt layer using reactive ion etching. Since controlling magnetic properties is separated from controlling granular nanostructure, FePt grains can be reduced by optimizing the mask layer and patterning process only. This process is also potentially compatible to any state-of-art vacuum process for other electronic devices wafers and heterostructured nanoparticles manufacturing.
A programmable ferroelectric single electron transistor
Authors: Liu Lu , Narayanan Vijay , Datta Suman
Published: February 2013

We experimentally demonstrate a programmable ferroelectric single electron transistor using direct monolithic integration of a multi-gate III-V (In0.7Ga0.3As) quantum well field effect transistor with a composite ferroelectric (lead zirconium titanate) and high-k (hafnium dioxide) gate stack. A split gate electrode configuration allows electrical tuning of the tunnel barrier profile and reconfigurable programming of the device to operate in both classical and Coulomb blockade mode. The ferroelectric gate stack under the split gate electrode further allows non-volatile operation in both modes. This demonstration is a significant step towards realization of a non-volatile, programmable binary decision diagram logic circuit for ultra low power operation.
Cell-free protein expression systems in microdroplets: Stabilization of interdroplet bilayers
Authors: Friddin Mark S. , Morgan Hywel , de Planque Maurits R. R.
Published: February 2013

Cell-free protein expression with bacterial lysates has been demonstrated to produce soluble proteins in microdroplets. However, droplet assays with expressed membrane proteins require the presence of a lipid bilayer. A bilayer can be formed in between lipid-coated aqueous droplets by bringing these into contact by electrokinetic manipulation in a continuous oil phase, but it is not known whether such interdroplet bilayers are compatible with high concentrations of biomolecules. In this study, we have characterized the lifetime and the structural integrity of interdroplet bilayers by measuring the bilayer current in the presence of three different commercial cell-free expression mixtures and their individual components. Samples of pure proteins and of a polymer were included for comparison. It is shown that complete expression mixtures reduce the bilayer lifetime to several minutes or less, and that this is mainly due to the lysate fraction itself. The fraction that contains the molecules for metabolic energy generation does not reduce the bilayer lifetime but does give rise to current steps that are indicative of lipid packing defects. Gel electrophoresis confirmed that proteins are only present at significant amounts in the lysate fractions and, when supplied separately, in the T7 enzyme mixture. Interestingly, it was also found that pure-protein and pure-polymer solutions perturb the interdroplet bilayer at higher concentrations; 10% (w/v) polyethylene glycol 8000 (PEG 8000) and 3 mM lysozyme induce large bilayer currents without a reduction in bilayer lifetime, whereas 3 mM albumin causes rapid bilayer failure. It can, therefore, be concluded that the high protein content of the lysates and the presence of PEG polymer, a typical lysate supplement, compromise the structural integrity of interdroplet bilayers. However, we established that the addition of lipid vesicles to the cell-free expression mixture stabilizes the interdroplet bilayer, allowing the exposure of interdroplet bilayers to cell-free expression solutions. Given that cell-free expressed membrane proteins can insert in lipid bilayers, we envisage that microdroplet technology may be extended to the study of in situ expressed membrane receptors and ion channels.
Fit for Planning? An Evaluation of the Application of Development Viability Appraisal Models in the UK Planning System
Authors: Crosby Neil , McAllister Pat , Wyatt Peter
Published: February 2013

In the context of its increasing use in policy formulation regarding planning obligations, we discuss a number of problematic issues in the application of development viability appraisal modelling in the UK planning system. The increased use of planning obligations to provide affordable housing and to mitigate the effects of negative externalities generated by new development is discussed. The methodology of development viability appraisal modelling is also outlined. Three types of problem are identified. First, there is a set of issues related to intrinsic model and input uncertainty that are problematic in the application of development viability modelling whatever the context. Second, there are problems that are specific to modelling for estimating or justifying planning obligations. In particular, a crucial input that remains contested and uncertain is threshold land value. Clear guidance can resolve this issue. Finally, and more fundamentally, due to spatial and temporal variation in the capacity of development sites to generate financial surpluses for planning obligations, policies that set rules or fix targets on planning obligations without regard to prevailing site and/or market conditions can reduce the supply of development and/or be prone to rapid obsolescence.
Effect of near-future seawater temperature rises on sea urchin sperm longevity
Authors: Binet M. T. , Doyle C. J.
Published: February 2013

Global warming has and will continue to warm the world’s oceans, which may have detrimental consequences for marine life. Studies assessing the impact of climate-change stressors on early life-stages of marine invertebrates have focussed on immediate fertilisation success or larval development, but have so far not considered gamete longevity. Recent studies have suggested that sea urchin fertilisation can take place for several hours, as dilute spermatozoa can travel to fertilise distant eggs, making gamete longevity an important factor in fertilisation success for some species. The longevity of spermatozoa from Heliocidaris tuberculata was assessed over a 3-h exposure to current ambient (20°C), near-future (24°C) and future (26°C) ocean-temperature scenarios. Sperm mitochondrial activity was also measured throughout the 3-h exposure using the stain Rhodamine 123 (Rh123) and flow cytometry. Sperm longevity, based on fertilisation success, significantly decreased following a 1-h exposure at 26°C, or a 3-h exposure at 24°C, relative to the 20°C treatment. However, sperm mitochondrial activity did not correlate with fertilisation success. Even when fertilisation success was below 20%, Rh123 uptake remained above 80%, indicating the presence of active mitochondria in non-viable spermatozoa. Our results suggested that at projected sea-surface temperatures, the longevity of sea urchin spermatozoa is reduced, which may have consequences for sea urchin population dynamics.
The effect of parasitism by a blood-feeding isopod on the otolith chemistry of host fish
Authors: Heagney Elizabeth C. , Gillanders Bronwyn M. , Suthers Iain M.
Published: February 2013

Otolith chemistry is widely used to discriminate fish stocks or populations, although many of the factors that determine trace-element concentrations within the otolith remain poorly understood. We investigated the effect of a blood-feeding isopod ectoparasite, Ceratothoa sp., on the otolith chemistry of yellowtail scad, Trachurus novaezelandiae. We sampled 65 fish from three subpopulations of T. novaezelandiae from Jervis Bay in south-eastern Australia, and used laser ablation (LA)–inductivelycoupled plasma mass spectrometry (ICPMS) to measure otolith lithium (Li) : calcium (Ca), magnesium (Mg) : Ca, strontium (Sr) : Ca and barium (Ba) : Ca from four consecutive summer and winter growth bands. Otoliths of parasitised fish were characterised by significantly lower Li : Ca and Mg : Ca, and higher Sr : Ca, than those of unparasitised individuals from the same subpopulation. The consistency of trends in otolith chemistry across ablation points and among subpopulations suggests that there is a consistent physiological mechanism through which Ceratothoa parasites affect the otolith chemistry of infected individuals. It is likely that a range of physical, metabolic, chemical and behavioural processes act in concert to influence the otolith chemistry of parasitised fish. Given the ubiquitous distribution of parasites in the marine environment, differential rates of parasitism among fish stocks, populations or migratory contingents may be an important but unappreciated factor driving stock- or population-based differences in otolith chemistry.
Downstream spawning migration by the amphidromous Australian grayling (Prototroctes maraena) in a coastal river in south-eastern Australia
Authors: Koster W. M. , Dawson D. R. , Crook D. A.
Published: February 2013

Understanding the reasons and cues for migration is crucial for developing effective conservation and management strategies of diadromous fishes. Spawning and movement patterns of the threatened diadromous Australian grayling (Prototroctes maraena) were investigated in the Bunyip River, Victoria, using drift sampling (2008–2011) and acoustic telemetry (2009–2010) during the autumn–winter spawning period of each year. Fifty-five adult fish (2009: n = 21; 2010: n = 34) were tagged and released in February ~15–30 km upstream of the Bunyip River estuary. Thirteen fish (2009: n = 7; 2010: n = 6) undertook rapid downstream migrations from March to April to reaches immediately upstream of the estuary. Drifting eggs were detected at multiple sites between April and July; however, the majority (78.8%) were collected in the lower reaches within ~0.5 km of the estuary in early–mid-May. Tagged adult fish arrived in this area 1–4 weeks before eggs were detected and usually moved back upstream within 2 weeks following the peak egg abundance. Downstream migration and peak egg abundance were associated with increased river flows. Although the proportion of fish that undertook migrations was low, low rates of tag retention in this species likely account for the failure to detect migration by many of the tagged individuals.
A search for muon-to-electron conversion at J-PARC: the COMET experiment
Authors: Kuno Yoshitaka
Published: February 2013

A new experimental search for the charged-lepton-flavor-violating process of neutrinoless muon-to-electron conversion by J-PARC E21 (the COMET experiment), which aims at a factor of 10 000 improvement over the current limit, is described, together with the physics motivation of charged lepton flavor violation. The first-stage approach of the COMET experiment (COMET Phase-I), which has recently been taken for earlier realization of the measurement, is also mentioned.
The AAA+ ATPases and HflB/FtsH Proteases of ‘Candidatus Phytoplasma mali’: Phylogenetic Diversity, Membrane Topology, and Relationship to Strain Virulence
Authors: Seemüller Erich , Sule Sandor , Kube Michael , Jelkmann Wilhelm , Schneider Bernd
Published: February 2013

Previous examination revealed a correlation of phytopathogenic data of ‘Candidatus Phytoplasma mali’ strains and the DNA sequence variability of a type ATP00464 hflB gene fragment. To further investigate such a relationship, all distinct genes previously annotated as hflB in the genome of ‘Ca. P. mali’ strain AT were fully sequenced and analyzed from a number of representative mild, moderate, and severe strains. The re-annotation indicated that the sequences encode six AAA+ ATPases and six HflB proteases. Each of the nine distinct deduced AAA+ proteins that were examined formed a coherent phylogenetic cluster. However, within these groups, sequences of three ATPases and three proteases from mild and severe strains clustered distantly, according to their virulence. This grouping was supported by an association with virulence-related amino acid substitutions. Another finding was that full-length genes from ATPase AP11 could only be identified in mild and moderate strains. Prediction of the membrane topology indicated that the long ATPase- and protease-carrying C-terminal tails of approximately half of the AAA+ proteins are extracellular, putatively facing the environment of the sieve tubes. Thus, they may be involved in pathogen–host interactions and may compromise phloem function, a major effect of phytoplasma infection. All full-length genes examined appear transcriptionally active and all deduced peptides show the key positions indicative for protein function.
Orientation and size-dependent mechanical modulation within individual secondary osteons in cortical bone tissue
Authors: Carnelli Davide , Vena Pasquale , Dao Ming , Ortiz Christine , Contro Roberto
Published: February 2013

Anisotropy is one of the most peculiar aspects of cortical bone mechanics; however, its anisotropic mechanical behaviour should be treated only with strict relationship to the length scale of investigation. In this study, we focus on quantifying the orientation and size dependence of the spatial mechanical modulation in individual secondary osteons of bovine cortical bone using nanoindentation. Tests were performed on the same osteonal structure in the axial (along the long bone axis) and transverse (normal to the long bone axis) directions along arrays going radially out from the Haversian canal at four different maximum depths on three secondary osteons. Results clearly show a periodic pattern of stiffness with spatial distance across the osteon. The effect of length scale on lamellar bone anisotropy and the critical length at which homogenization of the mechanical properties occurs were determined. Further, a laminate-composite-based analytical model was applied to the stiffness trends obtained at the highest spatial resolution to evaluate the elastic constants for a sub-layer of mineralized collagen fibrils within an osteonal lamella on the basis of the spatial arrangement of the fibrils. The hierarchical arrangement of lamellar bone is found to be a major determinant for modulation of mechanical properties and anisotropic mechanical behaviour of the tissue.
Starlings uphold principles of economic rationality for delay and probability of reward
Authors: Monteiro Tiago , Vasconcelos Marco , Kacelnik Alex
Published: February 2013

Rationality principles are the bedrock of normative theories of decision-making in biology and microeconomics, but whereas in microeconomics, consistent choice underlies the notion of utility; in biology, the assumption of consistent selective pressures justifies modelling decision mechanisms as if they were designed to maximize fitness. In either case, violations of consistency contradict expectations and attract theoretical interest. Reported violations of rationality in non-humans include intransitivity (i.e. circular preferences) and lack of independence of irrelevant alternatives (changes in relative preference between options when embedded in different choice sets), but the extent to which these observations truly represent breaches of rationality is debatable. We tested both principles with starlings (Sturnus vulgaris), training subjects either with five options differing in food delay (exp. 1) or with six options differing in reward probability (exp. 2), before letting them choose repeatedly one option out of several binary and trinary sets of options. The starlings conformed to economic rationality on both tests, showing strong stochastic transitivity and no violation of the independence principle. These results endorse the rational choice and optimality approaches used in behavioural ecology, and highlight the need for functional and mechanistic enquiring when apparent violations of such principles are observed.
Group size adjustment to ecological demand in a cooperative breeder
Authors: Zöttl Markus , Frommen Joachim G. , Taborsky Michael
Published: February 2013

Environmental factors can determine which group size will maximize the fitness of group members. This is particularly important in cooperative breeders, where group members often serve different purposes. Experimental studies are yet lacking to check whether ecologically mediated need for help will change the propensity of dominant group members to accept immigrants. Here, we manipulated the perceived risk of predation for dominant breeders of the cooperatively breeding cichlid fish
Neolamprologus pulcher
to test their response to unrelated and previously unknown immigrants. Potential immigrants were more readily accepted if groups were exposed to fish predators or egg predators than to herbivorous fish or control situations lacking predation risk. Our data are consistent with both risk dilution and helping effects. Egg predators were presented before spawning, which might suggest that the fish adjust acceptance rates also to a potential future threat. Dominant group members of
N. pulcher
apparently consider both present and future need of help based on ecological demand. This suggests that acceptance of immigrants and, more generally, tolerance of group members on demand could be a widespread response to ecological conditions in cooperatively breeding animals.
Symbiosis catalyses niche expansion and diversification
Authors: Joy Jeffrey B.
Published: February 2013

Interactions between species are important catalysts of the evolutionary processes that generate the remarkable diversity of life. Symbioses, conspicuous and inherently interesting forms of species interaction, are pervasive throughout the tree of life. However, nearly all studies of the impact of species interactions on diversification have concentrated on competition and predation leaving unclear the importance of symbiotic interaction. Here, I show that, as predicted by evolutionary theories of symbiosis and diversification, multiple origins of a key innovation, symbiosis between gall-inducing insects and fungi, catalysed both expansion in resource use (niche expansion) and diversification. Symbiotic lineages have undergone a more than sevenfold expansion in the range of host-plant taxa they use relative to lineages without such fungal symbionts, as defined by the genetic distance between host plants. Furthermore, symbiotic gall-inducing insects are more than 17 times as diverse as their non-symbiotic relatives. These results demonstrate that the evolution of symbiotic interaction leads to niche expansion, which in turn catalyses diversification.
FisB mediates membrane fission during sporulation in Bacillus subtilis
Authors: Doan Thierry , Coleman Jeff , Marquis Kathleen A. , Meeske Alex J. , Burton Briana M. , Karatekin Erdem , Rudner David Z.
Published: February 2013

How bacteria catalyze membrane fission during growth and differentiation is an outstanding question in prokaryotic cell biology. Here, we describe a protein (FisB, for fission protein B) that mediates membrane fission during the morphological process of spore formation in Bacillus subtilis. Sporulating cells divide asymmetrically, generating a large mother cell and smaller forespore. After division, the mother cell membranes migrate around the forespore in a phagocytic-like process called engulfment. Membrane fission releases the forespore into the mother cell cytoplasm. Cells lacking FisB are severely and specifically impaired in the fission reaction. Moreover, GFP-FisB forms dynamic foci that become immobilized at the site of fission. Purified FisB catalyzes lipid mixing in vitro and is only required in one of the fusing membranes, suggesting that FisB–lipid interactions drive membrane remodeling. Consistent with this idea, the extracytoplasmic domain of FisB binds with remarkable specificity to cardiolipin, a lipid enriched in the engulfing membranes and regions of negative curvature. We propose that membrane topology at the final stage of engulfment and FisB–cardiolipin interactions ensure that the mother cell membranes are severed at the right time and place. The unique properties of FisB set it apart from the known fission machineries in eukaryotes, suggesting that it represents a new class of fission proteins.
Retrospective audit to determine the diagnostic accuracy of Primovist‐enhanced MRI in the detection of hepatocellular carcinoma in cirrhosis with explant histopathology correlation
Authors: Baird Andrew J , Amos Gregory J , Saad Nivene F , Benson Mark D
Published: February 2013

Introduction

This study aims to determine the diagnostic accuracy of Primovist‐enhanced MRI in the detection of hepatocellular carcinoma (HCC) in cirrhosis, using liver explant histopathology correlation.

Methods

Thirty patients underwent a Primovist‐enhanced MRI prior to liver transplantation for cirrhosis at the Princess Alexandra Hospital from 2006 to June 2012. Pre‐contrast T1, T2 and post‐Primovist arterial, portal venous and delayed hepatobiliary phase sequences were routinely obtained. A retrospective audit of MRI reports determined whether HCCs was identified on pre‐transplantation imaging. Results were correlated to the explant liver histopathology. Specificity and sensitivity of Primovist in HCC identification in cirrhosis was determined.

Results

The time interval between preoperative MRI and transplantation ranged from the day of transplantation to 112 weeks pre‐transplantation. Thirty‐nine HCCs were identified histologically in explants. Fifteen HCCs were identified on pre‐transplant MRI in 11 patients, ranging from 11 to 43 mm, all confirmed on histopathology. Fourteen MRI studies identified no lesion, concordant on histology. Twenty‐four either well or moderately differentiated HCCs were identified on histopathology, all of which were less than 17 mm, were not depicted on MRI. No poorly differentiated HCCs were present in the explants. Two regenerative nodules were correctly identified on MRI. This correlated to a sensitivity of 42.5%, specificity of 100% and a positive predictive value of 100% and negative predictive value of 39.5%.

Conclusion

Primovist‐enhanced MRI is very accurate in the identification of HCC in cirrhosis, especially if the tumour is greater than 17 mm and undifferentiated. However, sensitivity is reduced for well‐ and moderately differentiated HCC less than 17 mm.
“To put men in a bottle”: Eroticism, kinship, female power, and transactional sex in Maputo, Mozambique
Authors: GROES‐GREEN CHRISTIAN
Published: February 2013

Eroticism, kinship, and gender all intersect in transactional sexual relationships between young women known ascurtidorasand older white men in Maputo, Mozambique. I draw on postcolonial feminism to argue that curtidoras’ erotic powers are a central part of sexual–economic exchanges with men and that senior female kin are deeply involved in processes of seduction and extraction of money. I conceptualize relationships between curtidoras, female kin, and male partners as “gendered triads of reciprocity” to unsettle Western stereotypes of female victims and patriarchal structures in Africa. Transactional sex often makes the partners mutually dependent and emotionally vulnerable, and, although moralities of exchange collide, young women tend to redistribute accumulated money from men among female seniors and kin.
The bodily threat of miracles: Security, sacramentality, and the Egyptian politics of public order
Authors: HEO ANGIE
Published: February 2013

This article examines the political and public culture of Coptic Christian miracles through the circulation and reproduction of images and the mimetic entanglements of artifacts and objects. To understand the threat posed by one case of a woman's oil‐exuding hand, this study points to how semiotic orders of security and sacramentality intersect in the regulation of bodily miracles. It explores Coptic Orthodox Church and Egyptian state efforts to contain the activity of images and transform the public nature of truthful witness and divine testimony. In doing so, it suggests how the material structure of saintly imagination introduces bodily and visual challenges to an authoritarian politics of public order.
Confessional pluralism and the civil society effect: Liberal mediations of Islam and secularism in contemporary Turkey
Authors: WALTON JEREMY F.
Published: February 2013

Practices and ideals of confessional pluralism and liberal interpretations of Islam have achieved new prominence in Turkish civil society in recent years. In this article, I marshal fieldwork conducted among a variety of Turkish Islamic civil society institutions to argue that confessional pluralism and liberal Islam have reoriented practices of politics and secularism in Turkey. As I demonstrate, liberal discourse about religious difference emerges within civil society as a foil to hegemonic, homogeneous visions of Islam on the part of the state. My principal theoretical contribution is the civil society effect: how the institutions and discourses of civil society are idealized and rendered distinct from state power. Ethnographically, I focus on two religious groups that have achieved organization within civil society: Turkish Alevis and supporters of the Sunni Hizmet Movement.
Thrombin inhibitors: surgical considerations and pharmacology
Authors: Breik Omar , Tadros Rami , Devitt Peter
Published: February 2013

The new thrombin inhibitors have provided an exciting opportunity for effective thromboprophylaxis without some of the disadvantages of the current anticoagulants. These drugs are orally administered, have predictable pharmacokinetics and dose–response, do not require monitoring and have an acceptable safety profile when used appropriately. However, inappropriate prescribing of these drugs may lead to catastrophic consequences. Clinicians need to be aware of some of the drawbacks associated with the use of dabigatran and, in particular, its reduced clearance in the setting of renal failure and the lack of an effective reversing agent when bleeding does occur. In this review, the evidence for efficacy and safety of dabigatran is discussed. We also aim to provide practical clinical advice on the pre‐ and post‐operative management of the elective and emergency surgical patient on dabigatran and provide guidelines for the management of acute haemorrhage in the context of dabigatran therapy.
EQUIVALENT OPTION PRICE WITH SUPPLY UNCERTAINTY
Authors: Shafran Aric P.
Published: February 2013

This paper compares two ex ante measures of the benefits of a project with supply uncertainty: compensating option price, the willingness to pay for a project, and equivalent option price, the willingness to accept to forego a project. The paper shows that compensating option price does not generally rank three or more projects correctly, even when the projects only impose a change in a single good. Equivalent option price, like equivalent variation with certain outcomes, always ranks three or more projects correctly. This paper also presents a method to empirically estimate equivalent option price using estimates of the benefits of certain changes. This approach is practically important so that the same study results can be used to estimate equivalent option price even as new projects are developed or as changes occur in the scientific information regarding the probabilities of various project outcomes. An application of the empirical method estimates the benefits of a policy to improve air and water quality when there is uncertainty about the effectiveness of the policy.
INVESTMENT BEHAVIOUR, CORPORATE CONTROL, AND PRIVATE BENEFITS OF CONTROL: EVIDENCE FROM A SURVEY OF UKRAINIAN FIRMS
Authors: Mykhayliv Dariya , Zauner Klaus G.
Published: February 2013

We analyse the impact of ownership and corporate control on firms’ investment using the 2001 survey of Yacoub et al. on Ukrainian firms. The model explains investment by output, financial and soft budget constraints, and corporate control (and ownership) categories potentially enjoying private benefits of control. We find that the corporate control model fits better than the ownership model, a negative relationship between state and employee control and firms’ investment, and evidence for the presence of soft budget constraints. A negative relationship between firms’ investment and the relative size of non‐monetary transactions strengthens the conclusion of private benefits of control impacting investment.
Development and characterization of a bladder cancer xenograft model using patient‐derived tumor tissue
Authors: Park Bumsoo , Jeong Byong Chang , Choi Yoon‐La , Kwon Ghee Young , Lim Joung Eun , Seo Seong Il , Jeon Seong Soo , Lee Hyun Moo , Choi Han Yong , Lee Kyu‐Sung
Published: February 2013

Most of the cancer xenograft models are derived from tumor cell lines, but they do not sufficiently represent clinical cancer characteristics. Our objective was to develop xenograft models of bladder cancer derived from human tumor tissue and characterize them molecularly as well as histologically. A total of 65 bladder cancer tissues were transplanted to immunodeficient mice. Passagable six cases with clinico‐pathologically heterogeneous bladder cancer were selected and their tumor tissues were collected (012T, 025T, 033T, 043T, 048T, and 052T). Xenografts were removed and processed for the following analyses: (i) histologic examination, (ii) short tandem repeat (STR) genotyping, (iii) mutational analysis, and (iv) array‐based comparative genomic hybridization (array‐CGH). The original tumor tissues (P 0) and xenografts of passage 2 or higher (≥P2) were analyzed and compared. As a result, hematoxylin and eosin staining revealed the same histologic architecture and degree of differentiation in the primary and xenograft tumors in all six cases. Xenograft models 043T_P2 and 048T_P2 had completely identical STR profiles to the original samples for all STR loci. The other models had nearly identical STR profiles. On mutational analysis, four out of six xenografts had mutations identical to the original samples for TP53, HRAS, BRAF, and CTNNB1. Array‐CGH analysis revealed that all six xenograft models had genomic alterations similar to the original tumor samples. In conclusion, our xenograft bladder cancer model derived from patient tumor tissue is expected to be useful for studying the heterogeneity of the tumor populations in bladder cancer and for evaluating new treatments.
The silence of Good Samaritan kidney donation in Australia: a survey of hospital websites
Authors: Bramstedt Katrina A. , Dave Sameer
Published: February 2013

It is common for living donor candidates to use the Internet as a tool to enhance their decision‐making process. Specifically, the websites of transplant hospitals can potentially be a vital source of information for those contemplating living donation. In an effort to explore the low incidence of Good Samaritan kidney donation (donations to strangers) in Australia, two raters conducted a nine‐attribute website content analysis for all hospitals which participate in these transplants (n = 15). Overall, the concept of living donation is relatively silent on Australian hospital websites. Only four hospitals mention their living donor program, and only one mentions their Good Samaritan program. No site linked directly to Australia's AKX Paired Kidney Exchange Program – the only program which facilitates pair and chain transplants in Australia. Further, information about deceased donation is nearly absent as well. An individual with the altruistic desire to donate will generally find scant or absent information about donation at the website of their local transplant hospital, although this information could easily be present as an educational tool which supports the consent process. Using a hospital website to educate the public about a clinical service should not be viewed as ethically problematic (solicitation), but rather an ethical essential.
Independent but Not Indifferent: Partisan Bias in Monetary Policy at the Fed
Authors: Clark William Roberts , Arel‐Bundock Vincent
Published: February 2013

Independent central banks are thought to be effective inflation hawks because they are run by technocrats with conservative monetary policy preferences. However, central bankers can only protect their independence by compromising with the elected officials who grant them their independence. Policy, therefore, is likely to be a weighted average of the preferences of the central bank and the government. Consequently, central bankers may be eager to help right‐wing governments stay in power and oppose the election of left‐wing governments. We show evidence from the United States that interest rates (a) decline as elections approach when Republicans control the White House, but rise when Democrats do; and (b) are sensitive to the inflation rate (output gap) when Democrats (Republicans) are in the White House. Thus, the Federal Reserve is a conditional inflation hawk. Since the Fed became operationally independent in 1951, the Republicans have exhibited a decided electoral advantage in presidential politics.
Invasion genetics of American cherry fruit fly in Europe and signals of hybridization with the European cherry fruit fly
Authors: Johannesen Jes , Keyghobadi Nusha , Schuler Hannes , Stauffer Christian , Vogt Heidrun
Published: February 2013

The American cherry fruit fly is an invasive pest species in Europe, of serious concern in tart cherry production as well as for the potential to hybridize with the European cherry fruit fly, Rhagoletis cerasi L. (Diptera: Tephritidae), which might induce new pest dynamics. In the first European reports, the question arose whether only the eastern American cherry fruit fly, Rhagoletis cingulata (Loew) (Diptera: Tephritidae), is present, or also the closely related western American cherry fruit fly, Rhagoletis indifferens Curran. In this study, we investigate the species status of European populations by comparing these with populations of both American species from their native ranges, the invasion dynamics in German (first report in 1993) and Hungarian (first report in 2006) populations, and we test for signals of hybridization with the European cherry fruit fly. Although mtDNA sequence genealogy could not separate the two American species, cross‐species amplification of 14 microsatellite loci separated them with high probabilities (0.99–1.0) and provided evidence for R. cingulata in Europe. German and Hungarian R. cingulata populations differed significantly in microsatellite allele frequencies, mtDNA haplotype and wing pattern distributions, and both were genetically depauperate relative to North American populations. The diversity suggests independent founding events in Germany and Hungary. Within each country, R. cingulata displayed little or no structure in any trait, which agrees with rapid local range expansions. In cross‐species amplifications, signals of hybridization between R. cerasi and R. cingulata were found in 2% of R. cingulata individuals and in 3% of R. cerasi. All putative hybrids had R. cerasi mtDNA indicating that the original between‐species mating involved R. cerasi females and R. cingulata males.
The salicylate 1,2‐dioxygenase as a model for a conventional gentisate 1,2‐dioxygenase: crystal structures of the G106A mutant and its adducts with gentisate and salicylate
Authors: Ferraroni Marta , Matera Irene , Bürger Sibylle , Reichert Sabrina , Steimer Lenz , Scozzafava Andrea , Stolz Andreas , Briganti Fabrizio
Published: February 2013

The salicylate 1,2‐dioxygenase (SDO) from the bacterium Pseudaminobacter salicylatoxidans BN12 is a versatile gentisate 1,2‐dioxygenase (GDO) that converts both gentisate (2,5‐dihydroxybenzoate) and various monohydroxylated substrates. Several variants of this enzyme were rationally designed based on the previously determined enzyme structure and sequence differences between the SDO and the ‘conventional’ GDO from Corynebacterium glutamicum. This was undertaken in order to define the structural elements that give the SDO its unique ability to dioxygenolytically cleave (substituted) salicylates. SDO variants M103L, G106A, G111A, R113G, S147R and F159Y were constructed and it was found that G106A oxidized only gentisate; 1‐hydroxy‐2‐naphthoate and salicylate were not converted. This indicated that this enzyme variant behaves like previously known ‘conventional’ GDOs. Crystals of the G106A SDO variant and its complexes with salicylate and gentisate were obtained under anaerobic conditions, and the structures were solved and analyzed. The amino acid residue Gly106 is located inside the SDO active site cavity but does not directly interact with the substrates. Crystal structures of G106A SDO complexes with gentisate and salicylate showed a different binding mode for salicylate when compared with the wild‐type enzyme. Thus, salicylate coordinated in the G106A variant with the catalytically active Fe(II) ion in an unusual and unproductive manner because of the inability of salicylate to displace a hydrogen bond that was formed between Trp104 and Asp174 in the G106A variant. It is proposed that this type of unproductive substrate binding might generally limit the substrate spectrum of ‘conventional’ GDOs.

Database

Structural data are available in the Protein Data Bank databases under the accession numbers 3NST, 3NWA, 3NVC
Mouse models of PIK3CA mutations: one mutation initiates heterogeneous mammary tumors
Authors: Koren Shany , Bentires‐Alj Mohamed
Published: February 2013

The phosphoinositide 3‐kinase (PI3K) signaling pathway is crucial for cell growth, proliferation, metabolism, and survival, and is frequently deregulated in human cancer, including ~ 70% of breast tumors. PIK3CA, the gene encoding the catalytic subunit p110α of PI3K, is mutated in ~ 30% of breast cancers. However, the exact mechanism of PIK3CA‐evoked breast tumorigenesis has not yet been defined. Genetically engineered mouse models are valuable for examining the initiation, development and progression of cancer. Transgenic mice harboring hotspot mutations in p110α have helped to elucidate breast cancer pathogenesis and increase our knowledge about molecular and cellular alterations in vivo. They are also useful for the development of therapeutic strategies. Here, we describe current mouse models of mutant PIK3CA in the mammary gland, and discuss differences in tumor latency and pathogenesis.