bluuebunny/crossref_metadata_2025 huggingface dataset:
A stabilized finite element method for convection–diffusion problems
Authors: Serghini Mounim A.
Published: December 2011

A stabilized finite element method (FEM) is presented for solving the convection–diffusion equation. We enrich the linear finite element space with local functions chosen according to the guidelines of the residual‐free bubble (RFB) FEM. In our approach, the bubble part of the solution (the microscales) is approximated via an adequate choice of discontinuous bubbles allowing static condensation. This leads to a streamline‐diffusion FEM with an explicit formula for the stability parameter τK that incorporates the flow direction, has the capability to deal with problems where there is substantial variation of the Péclet number, and gives the same limit as the RFB method. The method produces the same a priori error estimates that are typically obtained with streamline‐upwind Petrov/Galerkin and RFB. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2011
Stereoselective ring‐opening polymerization of D,L‐lactide, initiated by aluminum isopropoxides bearing tridentate nonchiral schiff‐base ligands
Authors: Matsubara Kouki , Terata Chihiro , Sekine Hiromichi , Yamatani Kenji , Harada Tatsuo , Eda Kiyoka , Dan Misato , Koga Yuji , Yasuniwa Munehisa
Published: December 2011

Ring‐opening polymerization of D,L‐lactide was stereoselectively achieved using newly designed aluminum alkoxide complexes as initiators. These half‐SALEN aluminum complexes bearing tridentate nonchiral Schiff‐base ligands are racemates, which provide chirality in the aluminum centers, efficiently afforded a stereoblock copolymer of D,L‐LA. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Identification of suitable areas for West Nile virus outbreaks in equid populations for application in surveillance plans: the example of the Castile and Leon region of Spain
Authors: RODRÍGUEZ-PRIETO V. , MARTÍNEZ-LÓPEZ B. , MARTÍNEZ M. , MUÑOZ M. J. , SÁNCHEZ-VIZCAÍNO J. M.
Published: December 2011

The introduction and rapid spread of West Nile virus (WNV) into new areas such as the American continent, associated also with the severity of the disease in humans and equids has increased concerns regarding the need to better prevent and control future WNV incursions. WNV outbreaks in equids usually occur under specific climatic and environmental conditions and, typically, before detection of WNV cases in humans. Targeting surveillance strategies in areas and time periods identified as suitable for WNV outbreaks in equids may act as an early-warning system to prevent disease in both equids and humans. This study used a GIS-based framework to identify suitable areas and time periods for WNV outbreak occurrence in one of the most important areas of equid production in Spain, i.e. Castile and Leon. Methods and results presented here may help to improve the early detection and control of future WNV outbreaks in Spain and other regions.
Organic matter transformations in the upper mesopelagic zone of the North Pacific: Chemical composition and linkages to microbial community structure
Authors: Kaiser Karl , Benner Ronald
Published: December 2011

Transformation processes in the euphotic and mesopelagic zones are of crucial importance to the biological pump and global elemental cycles. In this study, elemental stoichiometries and chemical compositions of particulate and dissolved organic matter (DOM) were investigated in the euphotic and upper mesopelagic zones of the North Pacific Subtropical Gyre. The distributions of bacterial biomarkers (D‐amino acids, muramic acid) and major biochemicals (amino acids, neutral sugars, amino sugars) indicated a direct link between microbial community structure and the biochemical composition of organic matter. Bacteria were major sources of organic C, N, and P in the upper mesopelagic zone. Heterotrophic bacterial transformations were important in the formation of biorefractory organic matter that is retained in the ocean on timescales of decades to millennia. Net removal rates for dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and major biochemicals were calculated for the upper mesopelagic zone (110–300 m). Dissolved hydrolyzable amino acids, neutral sugars, and amino sugars comprised 5–18% of DOC and 4–5% of DON removed in the upper mesopelagic zone, indicating these biochemicals were important components of semilabile DOM. Net removal rates of neutral sugars were 3–10 times higher than net removal rates of amino acids and amino sugars. This suggested that neutral sugars were the most reactive component among the three classes of biochemicals. Depth‐integrated net DOC removal rates indicated that DOC comprised 19–31% of total carbon export flux in the North Pacific gyre and supplied 27–93% of bacterial carbon demand in the upper mesopelagic zone.
Validity of the Remote Food Photography Method (RFPM) for Estimating Energy and Nutrient Intake in Near Real‐Time
Authors: Martin Corby K. , Correa John B. , Han Hongmei , Allen H. Raymond , Rood Jennifer C. , Champagne Catherine M. , Gunturk Bahadir K. , Bray George A.
Published: December 2011

Two studies are reported; a pilot study to demonstrate feasibility followed by a larger validity study. Study 1's objective was to test the effect of two ecological momentary assessment (EMA) approaches that varied in intensity on the validity/accuracy of estimating energy intake (EI) with the Remote Food Photography Method (RFPM) over 6 days in free‐living conditions. When using the RFPM, Smartphones are used to capture images of food selection and plate waste and to send the images to a server for food intake estimation. Consistent with EMA, prompts are sent to the Smartphones reminding participants to capture food images. During Study 1, EI estimated with the RFPM and the gold standard, doubly labeled water (DLW), were compared. Participants were assigned to receive Standard EMA Prompts (n = 24) or Customized Prompts (n = 16) (the latter received more reminders delivered at personalized meal times). The RFPM differed significantly from DLW at estimating EI when Standard (mean ± s.d. = −895 ± 770 kcal/day, P < 0.0001), but not Customized Prompts (−270 ± 748 kcal/day, P = 0.22) were used. Error (EI from the RFPM minus that from DLW) was significantly smaller with Customized vs. Standard Prompts. The objectives of Study 2 included testing the RFPM's ability to accurately estimate EI in free‐living adults (N = 50) over 6 days, and energy and nutrient intake in laboratory‐based meals. The RFPM did not differ significantly from DLW at estimating free‐living EI (−152 ± 694 kcal/day, P = 0.16). During laboratory‐based meals, estimating energy and macronutrient intake with the RFPM did not differ significantly compared to directly weighed intake.
X-ray magnetic circular dichroism in Co2FeGa: First-principles calculations
Authors: Kukusta D. A. , Antonov V. N. , Yaresko A. N.
Published: December 2011

The electronic structure and x-ray magnetic circular dichroism (XMCD) spectra of the Heusler alloy Co2FeGa were investigated theoretically from first principles, using the fully relativistic Dirac linear MT-orbital (LMTO) band structure method. Densities of valence states, orbital and spin magnetic moments are analyzed and discussed. The origin of the XMCD spectra in the Co2FeGa compound is examined. The calculated results are compared with available experimental data.
The origin of athermal training in polycrystalline metallic exchange bias thin films
Authors: Kaeswurm B. , O’Grady K.
Published: December 2011

The phenomenon of training in exchange bias systems has no clear and unambiguous explanation. It is known that the training effect consists of an athermal and a thermal component where the latter derives from the well understood thermal instability in the bulk of the antiferromagnetic (AF) grains. In this work, we report on a study of the magnetic properties of a tri-layer system consisting of F/AF/F where reversal of the individual ferromagnetic (F) layers shows that the athermal training effect derives solely from the interface spin configuration and not from the bulk of the AF grains. We propose a model whereby the origin of the training derives from the degree of order in interfacial spin clusters which lie in a thermo-remanent state after the AF is set and whose order is disrupted by the application of a reverse field resulting in a reduced coercivity and the characteristic change in the loop shape.
In-situ x-ray diffraction studies on post-deposition vacuum-annealing of ultra-thin iron oxide films
Authors: Bertram F. , Deiter C. , Pflaum K. , Suendorf M. , Otte C. , Wollschläger J.
Published: December 2011

A maghemite (γ-Fe2O3) film of 8.3 nm thickness is epitaxially grown on MgO(001) single crystal substrate by reactive molecular beam epitaxy. Chemical composition and crystal structure of the surface was studied by x-ray photoelectron spectroscopy and low energy electron diffraction, respectively. Afterwards the sample was moved to a heating cell for in situ x-ray diffraction experiments on the post-deposition annealing process in high-vacuum to study structural phase transitions of the iron oxide film. The iron oxide film is reduced with increasing temperature. This reduction occurs in two steps that are accompanied by structural transitions. The first step is a reduction from γ-Fe2O3 to Fe3O4 at 360 °C and the second step is the reduction from Fe3O4 to FeO at 410 °C.
A comparative study of Langmuir surfactant films: Grazing incidence x-ray off-specular scattering vs. x-ray specular reflectivity
Authors: Dai Yeling , Lin Binhua , Meron Mati , Kim Kyungil , Leahy Brian , Shpyrko Oleg G.
Published: December 2011

Surface monolayers assembled on a liquid sub-phase represent a class of systems that is of great interest for studies of phase transitions in quasi-2D systems, chemical self-assembly, surfactant behavior, and biologically relevant monolayers and membranes. X-ray scattering is ideal for studying structural, dynamic, and mechanical properties of these surface monolayers at nanoscale due to the penetrating ability and short wavelength of x-rays. We show here that grazing incidence x-ray off-specular scattering (GIXOS) provides rapid access to in-plane and out-of-plane nanoscale structure, surface fluctuating modes, and potentially bending stiffness. We show that analysis of GIXOS data is highly sensitive to resolution effects. We further present detailed analysis of GIXOS from phospholipid 1,2-dipalmitoyl-phosphatidyl-choline C40H80NO8P (DPPC) and obtain quantitative, angstrom-resolution details of electron density profile normal to the surface that is comparable to those that are obtained from specular x-ray reflectivity measurements. We compare these GIXOS results to x-ray reflectivity measurements performed on the same samples. While electron density and main structural characteristics (such as monolayer thickness) obtained by GIXOS agree with x-ray reflectivity results, the interfaces of GIXOS-derived density profiles are found to be systematically sharper than those obtained with x-ray reflectivity. The possible reasons for these differences are discussed.
Small radius solitons in magnets with a strong planar anisotropy
Authors: Filin D. V. , Ivanov B. A.
Published: December 2011

The stable topological solitons with a small radius exist for ferromagnets with not small anisotropy. Even in the case of rather strong planar anisotropy, the spatial anisotropy of the soliton solution turns out to be so small that a soliton in dynamical experiments behaves similar to that for the case of a purely uniaxial model.
Analyzing photovoltaic effect of double-layer organic solar cells as a Maxwell-Wagner effect system by optical electric-field-induced second-harmonic generation measurement
Authors: Taguchi Dai , Shino Tatsunori , Chen Xiangyu , Zhang Le , Li Jun , Weis Martin , Manaka Takaaki , Iwamoto Mitsumasa
Published: December 2011

By using time-resolved optical electric-field-induced second-harmonic generation measurement, we directly probed photo-voltage generation process in organic double-layer (pentacene/C60) solar cells. Results showed that photoillumination induced negative excess charge Qs = −3.6 × 10−9 C/cm2 at the pentacene/C60 interface, and the induced charge caused generation of the open-circuit voltage 0.26 V. Using an equivalent circuit based on a Maxwell-Wagner (MW) effect model well accounted for the excess charge accumulation process. The MW model analysis also well accounted for the open-circuit voltage, the short-circuit current, and the fill-factor of organic solar cells (OSCs). We concluded that the excess charges due to the MW effect give a significant effect on the photovoltaic effect of OSCs.
Variational solution of the three-dimensional Schrödinger equation using plane waves in adaptive coordinates
Authors: Pérez-Jordá José M.
Published: December 2011

A series of improvements for the solution of the three-dimensional Schrödinger equation over a method introduced by Gygi [F. Gygi, Europhys. Lett. 19, 617 (1992)10.1209/0295-5075/19/7/009; F. Gygi, Phys. Rev. B 48, 11692 (1993)10.1103/PhysRevB.48.11692] are presented. As in the original Gygi's method, the solution (orbital) is expressed by means of plane waves in adaptive coordinates \documentclass[12pt]{minimal}\begin{document}$\mathbf {u}$\end{document}u, where \documentclass[12pt]{minimal}\begin{document}$\mathbf {u}$\end{document}u is mapped from Cartesian coordinates, \documentclass[12pt]{minimal}\begin{document}$\mathbf {u} = f(\mathbf {r})$\end{document}u=f(r). The improvements implemented are threefold. First, maps are introduced that allow the application of the method to atoms and molecules without the assistance of the supercell approximation. Second, the electron-nucleus singularities are exactly removed, so that pseudo-potentials are no longer required. Third, the sampling error during integral evaluation is made negligible, which results in a true variational, second-order energy error procedure. The method is tested on the hydrogen atom (ground and excited states) and the \documentclass[12pt]{minimal}\begin{document}$\mathrm{H_2^+}$\end{document}H2+ molecule, resulting in milli-Hartree accuracy with a moderate number of plane waves.
Pressure effects on the transitions between disordered phases in supercooled liquid silicon
Authors: Garcez K. M. S. , Antonelli A.
Published: December 2011

We investigate the pressure effects on the transitions between the disordered phases in supercooled liquid silicon through Monte Carlo simulations and efficient methods to compute free energies. Our calculations, using an environment dependent interatomic potential for Si, indicate that at zero pressure the liquid-liquid phase transition, between the high density liquid and the low density liquid, occurs at a temperature \documentclass[12pt]{minimal}\begin{document}$\rm 325 K$\end{document}325K below melting. We found that the liquid-liquid transition temperature decreases with increasing pressure, following the liquid-solid coexistence curve. As pressure increases, the liquid-liquid coexistence curve approaches the region where the glass transition between the low density liquid and the low density amorphous takes place. Above 5 GPa, our calculations show that the liquid-liquid transition is suppressed by the glassy dynamics of the system. We also found that above 5 GPa, the glass transition temperature is lower than that at lower pressures, suggesting that under these conditions the glass transition occurs between the high density liquid and the high density amorphous.
Modulational instabilities in two-dimensional magnetized dust-lattice
Authors: Farokhi B. , Abdikian A.
Published: December 2011

The transverse oscillations of paramagnetic dust grains in hexagonal dusty plasma crystal are discussed. The nonlinearity, which is related to the sheath electric/magnetic field(s) and to the weak inter grain interactions (magnetic dipole), is shown to lead to the generation of phase harmonics. In the case of propagating two-dimensional transverse dust-lattice modes in an arbitrary direction, it is shown the modulational instability of the carrier wave is due to self-interaction. The stability depends on the form of the electric field, the magnetic field, and the magnetic permeability of dust particles. The long term evolution of the modulated wave packet is described by a discrete nonlinear Schrodinger equation and it is solved numerically by Adomian decomposition method.
On the theoretical description of nucleation in confined space
Authors: Schmelzer Jürn W. P. , Abyzov Alexander S.
Published: December 2011

In a recent paper, Kozisek et al. [J. Chem. Phys. 134, 094508 (2011)] have demonstrated for four different cases of phase formation that the work of formation of critical clusters required to form in the system in some given time a first experimentally measurable cluster of the new phase depends in a logarithmic way on the volume of the system. This result was obtained based on the numerical solution of the kinetic equations describing nucleation and growth processes and the obtained in this way steady-state cluster size distributions. Here a straightforward alternative analytical interpretation of this result is proposed by computing directly the mean expectation times of formation of supercritical clusters. It is proven strictly that this result is generally independent of the kind of nucleation (homogeneous or heterogeneous) or specific realization (condensation, cavitation, crystallization, segregation, etc.) considered. It is shown that such behavior is simply a consequence of the linear dependence of the steady-state nucleation rate on the volume of the system, neither time-lag or primary depletion (due to the establishment of steady-state cluster size distributions for subcritical clusters) or secondary depletion (caused by the change of the state of the ambient phase due to the formation and growth of supercritical clusters and connected with finite size effects) are required for the interpretation of such result. In a second step, this analytical result is extended accounting for the growth of the supercritical cluster to directly measurable sizes. Finally, an analytical foundation of the method of determination of the critical supersaturation as employed by Kozisek et al. is developed and the results obtained via the computation and analysis of steady-state cluster size distributions and calculation of mean expectation times for formation of the first supercritical clusters are compared. Some further general problems of nucleation and growth in finite closed systems are discussed, in addition.
Effect of gold nano-particles on switch-on voltage and relaxation frequency of nematic liquid crystal cell
Authors: Inam M. , Singh G. , Biradar A. M. , Mehta D. S.
Published: December 2011

We report the observation of large changes in the electro-optical properties of nematic liquid crystal (NLC) due to inclusion of small concentration of 10 nm diameter gold nanoparticles (GNPs). It is observed that GNPs lower switch-on voltage and also lower the relaxation frequency with applied voltage (AC field) to NLC cell. These studies of GNP doped NLC cell have been done using optical interferometry and capacity measurement by impedance analyzer. The change in threshold voltage and relaxation frequency by doping GNPs in NLC is explained theoretically.
Germany’s high-tech success due to (gasp!) government
Authors: Kramer David
Published: December 2011

Could the German model of applied research be emulated as the US struggles to retain what remains of its manufacturing sector?
Differential effects of linoleic and alpha-linolenic fatty acids on spatial and temporal mitochondrial distribution and activity in bovine oocytes
Authors: Marei Waleed F. , Wathes D. Claire , Fouladi-Nashta Ali A.
Published: December 2011

Using specific stains and confocal microscope imaging, the patterns of mitochondrial distribution, mitochondrial inner membrane potential and reactive oxygen species (ROS) levels during bovine oocyte maturation were determined in the presence or absence of physiological concentrations of linoleic acid (LA; 100 µM) or α-linolenic acid (ALA; 50 µM). Mitochondrial distribution in control oocytes at 0 h was mainly peripheral and changed to a diffused pattern after 1 h of culture; this was maintained up to 24 h. Mitochondrial clusters were observed during the early hours of maturation (1–4 h); the majority of these were arranged in perinuclear fashion. LA supplementation resulted in: (1) delayed redistribution of the mitochondria from a peripheral to a diffuse pattern and a decreased percentages of oocytes showing perinuclear mitochondrial clusters, (2) decreased mitochondrial inner membrane potential at 1 and 24 h compared with the control and (3) higher ROS levels, associated with a lower nuclear maturation rate. In contrast, ALA supplementation had no effect on mitochondrial distribution and activity and decreased ROS levels compared with the control; this was associated with an increased nuclear maturation rate. In conclusion, LA induced alterations in mitochondrial distribution and activity as well as increasing ROS levels, which mediate, at least in part, the inhibitory effect on oocyte maturation.
Contribution of working memory in parity and proportional judgments
Authors: Szymanik Jakub , Zajenkowski Marcin
Published: December 2011

This paper presents experimental evidence on the differences in a sentence–picture verification task under additional memory load between parity and proportional quantifiers. We asked subjects to memorize strings of four or six digits, then to decide whether a quantified sentence was true for a given picture, and finally to recall the initially given string of numbers. The results show that: (a) proportional quantifiers are more difficult than parity quantifiers with respect to reaction time and accuracy; (b) maintaining either four or six elements in working memory has the same effect on the processing of parity quantifiers; (c) however, in the case of proportional quantifiers subjects perform better in the verification tasks under the six-digit load condition, and (d) even though the strings of four numbers were better recalled by subjects after judging parity there is no difference between quantifiers in the case of the six-element condition. We briefly outline two alternative explanations for the observed phenomena rooted in the computational model of quantifier verification and the different theories of working memory.
Squib: A deflationary account of invited inferences
Authors: Noveck Ira , Bonnefond Mathilde , Henst Jean-Baptiste Van der
Published: December 2011

This squib reconsiders Geis & Zwicky’s influential proposal on Invited Inference, according to which conditionals are regularly “perfected” to biconditionals. We first show that the “regularity” assumption attached to conditional perfection is doubtful in light of established experimental findings concerning other logical terms, such as Some and or and the conjunction and. We then review existing conditional data with the aim of making them cohere with these other experimental findings. We argue that (a) the process that leaves the impression of a biconditional reading (the acceptance of a fallacious argument such as the Affirmation of the Consequent) arises only after all participants detect a violation on-line from what is essentially a surprising minor premise and that; (b) some participants make an effort to adjust to such unexpected violations at a relatively small cognitive cost in order to accept invalid arguments while others persist in rejecting whatever follows and at a greater cognitive cost. Both of these features of conditional processing undermine claims from Geis & Zwicky’s proposal.
Diet and lifestyle
Authors: Morrell Jonathan , Morrell Jacqueline
Published: December 2011

• Consume a healthy, balanced diet.

• Aim for a healthy body weight and shape.

• Reduce saturated and trans fats and substitute with non-hydrogenated, unsaturated fats. Choose whole grains as the main form of carbohydrates, and consume a diet high in fruit and vegetables.

• Be physically active.

• Avoid use of (and exposure to) tobacco products.
Floral volatiles, pollinator sharing and diversification in the fig–wasp mutualism: insights from
Ficus natalensis
, and its two wasp pollinators (South Africa)
Authors: Cornille A. , Underhill J. G. , Cruaud A. , Hossaert-McKey M. , Johnson S. D. , Tolley K. A. , Kjellberg F. , van Noort S. , Proffit M.
Published: December 2011

Combining biogeographic, ecological, morphological, molecular and chemical data, we document departure from strict specialization in the fig-pollinating wasp mutualism. We show that the pollinating wasps
Elisabethiella stuckenbergi
and
Elisabethiella socotrensis
form a species complex of five lineages in East and Southern Africa. Up to two morphologically distinct lineages were found to co-occur locally in the southern African region. Wasps belonging to a single lineage were frequently the main regional pollinators of several
Ficus
species. In South Africa, two sister lineages,
E. stuckenbergi
and
E. socotrensis
, pollinate
Ficus natalensis
but only
E. stuckenbergi
also regularly pollinates
Ficus burkei
. The two wasp species co-occur in individual trees of
F. natalensis
throughout KwaZulu-Natal. Floral volatile blends emitted by
F. natalensis
in KwaZulu-Natal were similar to those emitted by
F. burkei
and different from those produced by other African
Ficus
species. The fig odour similarity suggests evolutionary convergence to attract particular wasp species. The observed pattern may result from selection for pollinator sharing among
Ficus
species. Such a process, with one wasp species regionally pollinating several hosts, but several wasp species pollinating a given
Ficus
species across its geographical range could play an important role in the evolutionary dynamics of the
Ficus
-pollinating wasp association.
The polio-eradication programme and issues of the end game
Authors: Minor Philip D.
Published: December 2011

Poliovirus causes paralytic poliomyelitis, an ancient disease of humans that became a major public-health issue in the 20th century. The primary site of infection is the gut, where virus replication is entirely harmless; the two very effective vaccines developed in the 1950s (oral polio vaccine, or OPV, and inactivated polio vaccine, or IPV) induce humoral immunity, which prevents viraemic spread and disease. The success of vaccination in middle-income and developing countries encouraged the World Health Organization to commit itself to an eradication programme, which has made great advances. The features of the infection, including its largely silent nature and the ability of the live vaccine (OPV) to evolve and change in vaccine recipients and their contacts, make eradication particularly challenging. Understanding the pathogenesis and virology of the infection is of major significance as the programme reaches its conclusion.
A Reevaluation of Rice Mitochondrial Evolution Based on the Complete Sequence of Male-Fertile and Male-Sterile Mitochondrial Genomes
Authors: Bentolila Stéphane , Stefanov Stefan
Published: December 2011

Plant mitochondrial genomes have features that distinguish them radically from their animal counterparts: a high rate of rearrangement, of uptake and loss of DNA sequences, and an extremely low point mutation rate. Perhaps the most unique structural feature of plant mitochondrial DNAs is the presence of large repeated sequences involved in intramolecular and intermolecular recombination. In addition, rare recombination events can occur across shorter repeats, creating rearrangements that result in aberrant phenotypes, including pollen abortion, which is known as cytoplasmic male sterility (CMS). Using next-generation sequencing, we pyrosequenced two rice (Oryza sativa) mitochondrial genomes that belong to the indica subspecies. One genome is normal, while the other carries the wild abortive-CMS. We find that numerous rearrangements in the rice mitochondrial genome occur even between close cytotypes during rice evolution. Unlike maize (Zea mays), a closely related species also belonging to the grass family, integration of plastid sequences did not play a role in the sequence divergence between rice cytotypes. This study also uncovered an excellent candidate for the wild abortive-CMS-encoding gene; like most of the CMS-associated open reading frames that are known in other species, this candidate was created via a rearrangement, is chimeric in structure, possesses predicted transmembrane domains, and coopted the promoter of a genuine mitochondrial gene. Our data give new insights into rice mitochondrial evolution, correcting previous reports.
Similarity in parasite community structure may be used to trace latitudinal migrations of Odontesthes smitti along Argentinean coasts
Authors: Carballo M. C. , Cremonte F. , Navone G. T. , Timi J. T.
Published: December 2011

The aims of this study were to determine the existence of migratory movements and to identify ecological stocks of the silverside Odontesthes smitti along its distribution in the Southern Atlantic Ocean, using metazoan parasites as biological tags. Samples were obtained from San José Gulf (SJ) (42° 25′ S; 64° 07′ W) and Nuevo Gulf (NG) (42° 47′ S; 65° 02′ W) in north Patagonia during winter and summer and in waters off Mar del Plata (MDP) (38° 03′ S; 57° 32′ W), Bonaerense region, during winter. Fifteen parasite species were collected. Multivariate statistical procedures on parasite community data showed strong effect of host size on the structure of parasite assemblages. Taking into account the variations among samples due to host size, the differential structure of parasite communities between SJ and NG suggests that fish inhabiting these localities could belong to different ecological stocks. Fish from MDP and SJ caught in summer showed similar composition in their parasite assemblages, which is congruent with a migratory cycle that implies that fish caught in MDP during winter inhabit SJ during summer. Further evidence of the Patagonian origin of MDP O. smitti is the presence of the digenean Proctotrema bartolii in fish from both regions. Proctotrema bartolii is acquired by O. smitti only in the Magellanic province, where its intermediate host, Darina solenoides, is distributed. The analyses suggest that O. smitti inhabiting north Patagonian gulfs could belong to different ecological stocks and that O. smitti caught in MDP could have come from SJ.
Experimental warming alters spring phenology of certain plant functional groups in an early successional forest community
Authors: Rollinson Christine R. , Kaye Margot W.
Published: December 2011

Experimental study of the effects of projected climate change on plant phenology allows us to isolate effects of warming on life‐history events such as leaf out. We simulated a 2 °C temperature increase and 20% precipitation increase in a recently harvested temperate deciduous forest community in central Pennsylvania,USA, and observed the leaf out phenology of all species in 2009 and 2010. Over 130 plant species were monitored weekly in study plots, but due to high variability in species composition among plots, species were grouped into five functional groups: short forbs, tall forbs, shrubs, small trees, and large trees. Tall forbs and large trees, which usually emerge in the late spring, advanced leaf out 14–18 days in response to warming. Short forbs, shrubs, and small trees emerge early in spring and did not alter their phenology in response to warming or increased precipitation treatments. Earlier leaf out of tall forbs and large trees coincided with almost 3 weeks of increased community‐level leaf area index, indicating greater competition and a condensed spring green‐up period. While phenology of large trees and tall forbs appears to be strongly influenced by temperature‐based growth cues, our results suggest that photoperiod and chilling cues more strongly influence the leaf out of other functional groups. Reduced freeze events and warmer temperatures from predicted climate change will interact with nontemperature growth cues to have cascading consequences throughout the ecosystem.
Plant dispersal in the sub‐Antarctic inferred from anisotropic genetic structure
Authors: BORN CÉLINE , Le ROUX PETER C. , SPOHR COLIN , McGEOCH MELODIE A. , Van VUUREN BETTINE JANSEN
Published: December 2011

Climatic conditions and landscape features often strongly affect species’ local distribution patterns, dispersal, reproduction and survival and may therefore have considerable impacts on species’ fine‐scale spatial genetic structure (SGS). In this study, we demonstrate the efficacy of combining fine‐scale SGS analyses with isotropic and anisotropic spatial autocorrelation techniques to infer the impact of wind patterns on plant dispersal processes. We genotyped 1304 Azorella selago (Apiaceae) specimens, a wind‐pollinated and wind‐dispersed plant, from four populations distributed across sub‐Antarctic Marion Island. SGS was variable with Sp values ranging from 0.001 to 0.014, suggesting notable variability in dispersal distance and wind velocities between sites. Nonetheless, the data supported previous hypotheses of a strong NW–SE gradient in wind strength across the island. Anisotropic autocorrelation analyses further suggested that dispersal is strongly directional, but varying between sites depending on the local prevailing winds. Despite the high frequency of gale‐force winds on Marion Island, gene dispersal distance estimates (σ) were surprisingly low (<10 m), most probably because of a low pollen dispersal efficiency. An SGS approach in association with isotropic and anisotropic analyses provides a powerful means to assess the relative influence of abiotic factors on dispersal and allow inferences that would not be possible without this combined approach.
Bacterial L‐forms on tap: an improved methodology to generate Bacillus subtilis L‐forms heralds a new era of research
Authors: Devine Kevin M.
Published: December 2011

Bacterial L‐forms are cell wall‐less forms of bacteria that usually grow with a conventional cell wall. Despite being important for research, L‐forms are difficult to generate reproducibly and research in this area is challenging. Domínguez‐Cuevas et al. (2011) report a method to rapidly, quantitatively and reproducibly generate populations of L‐forms in Bacillus subtilis. Importantly, the methodology may be applicable to other bacteria heralding a new era of L‐form research. Moreover, the genetic requirements of this method provide insights into how Lipid II synthesis and autolysin expression/activity are normally balanced and the central role of the WalRK two‐component system in this process.
Clear cell variant of squamous cell carcinoma originating in the esophagus: Report of a case with immunohistochemical and oncogenetic analyses
Authors: Imamhasan Abdukadir , Mitomi Hiroyuki , Saito Tsuyoshi , Arakawa Atsushi , Yao Takashi
Published: December 2011

The cutaneous clear cell squamous cell carcinoma (SCC) is a rare tumor thought to be associated with hair follicle or skin appendage differentiation. We report herein a rare variant case of a clear cell SCC originating in the esophagus. A 70‐year‐old Japanese man was found to have a tumor in the esophagus. The excised neoplasm showed dominance of clear cell over conventional SCC components; the two components in an apparent continuum. The clear cells, regular in size with a moderate nuclear/cytoplasmic ratio and relatively hyperchromatic and centrally located nuclei, were compactly arranged in sheets. Glycogen deposition was apparent on PAS staining with or without diastase digestion and under the electron microscope. The clear cell SCC components were positive for cytokeratin (CK)7, CK8, CK18 and CK19, but were negative for CK5/6 or CK14. Reciprocal staining patterns of CKs were apparent in conventional SCC components. The present case and cutaneous clear cell SCC counterparts share some histopathologic characteristics whereas CKs expression differs between the two. Overexpression of p53 protein, without evidence of any mutation, and reduced p16INK4a were noted in both clear cell and conventional SCC components. No mutations of Kras, BRAF or β‐catenin genes were found in both tumor components.
Expression of cancer stem cell markers ALDH1, CD44 and CD133 in primary tumor and lymph node metastasis of gastric cancer
Authors: Wakamatsu Yuta , Sakamoto Naoya , Oo Htoo Zarni , Naito Yutaka , Uraoka Naohiro , Anami Katsuhiro , Sentani Kazuhiro , Oue Naohide , Yasui Wataru
Published: December 2011

Gastric cancer (GC) is one of the most common malignancies worldwide. Recently, cancer stem cells (CSCs) in tumors were found to possess the ability to sustain tumor self‐renewal, initiate tumor progression, and possibly also contribute to cancer metastasis. We immunohistochemically examined expression and distribution of representative CSC markers ALDH1, CD44, and CD133 in primary tumors and lymph node metastasis of GC. Among 190 GC primary tumors, 104 (55%) were positive for ALDH1, 117 (62%) were positive for CD44, and 18 (9%) were positive for CD133. Expression of these three CSC markers was significantly associated with advanced clinicopathologic factors. Patients with CD44‐ and CD133‐positive GC had a poorer survival rate than patients with CD44‐ and CD133‐negative GC (CD44: P < 0.001, CD133: P= 0.006). Univariate and multivariate Cox proportional hazards analysis revealed tumor node metastasis stage, CD44 expression, and CD133 expression to be independent predictors of survival in patients with GC. Comparison of CSC markers in primary and metastatic sites showed ALDH1 positivity to be significantly higher in diffuse‐type lymph node metastasis than in the primary tumor (P < 0.001). These results indicate that these CSC markers are important in tumor invasion and metastasis and may be good markers indicating long‐term survival in patients with GC.
Predictive value of HBsAg quantification for determining the clinical course of genotype C HBeAg‐negative carriers
Authors: Park Hana , Lee Jung Min , Seo Ju Hee , Kim Hyon Suk , Ahn Sang Hoon , Kim Do Young , Han Kwang‐Hyub , Chon Chae Yoon , Park Jun Yong
Published: December 2011

Background/Aims

Hepatitis B virus surface antigen (HBsAg) quantification has been suggested to discriminate inactive carriers from hepatitis e antigen (HBeAg) negative chronic hepatitis, but it could be genotype‐dependent. We studied the predictive value of HBsAg quantification in genotype C HBeAg‐negative hepatitis B virus (HBV) carriers.

Methods

We recruited 104 HBeAg‐negative HBV carriers with HBV DNA levels < 2,000 IU/ml and normal alanine aminotransferase (ALT) levels for at least 12 months and prospectively followed them for > 36 months. Patients were classified into two groups: inactive carriers (IC) who showed HBV DNA levels < 2,000 IU/ml and persistently ALT ≤ 40 IU/ml throughout the follow‐up period and patients with HBeAg‐negative chronic hepatitis (ENH).

Results

After follow‐up, 73 patients were categorized into the IC group and 31 patients into the ENH group. HBsAg levels were significantly lower in the IC group than in the ENH group. The diagnostic accuracy of single‐point HBsAg levels for predicting viral activation was favourable (AUROC = 0.710, P < 0.001). Diagnostic accuracy improved when HBsAg was combined with baseline HBV DNA levels (AUROC = 0.750, P < 0.001). The combination of HBsAg levels > 850 IU/ml and HBV DNA > 850 IU/ml predicted the reactivation of HBV replication with 84.6% diagnostic accuracy.

Conclusions

Although it is inferior to other genotypes and to serum HBV DNA alone, single‐point HBsAg level has a favourable diagnostic accuracy in genotype C HBeAg‐negative HBV carriers and is expected to provide additional information for managing chronic hepatitis B.
Melatonin attenuates kainic acid‐induced neurotoxicity in mouse hippocampus via inhibition of autophagy and α‐synuclein aggregation
Authors: Chang Chia‐Fu , Huang Hui‐Ju , Lee Hsin‐Chen , Hung Kai‐Chih , Wu Rong‐Tsun , Lin Anya Maan‐Yuh
Published: December 2011

Abstract:  In this study, the protective effect of melatonin on kainic acid (KA)‐induced neurotoxicity involving autophagy and α‐synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3‐II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA‐induced LC3‐II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA‐induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro‐apoptotic role of autophagy in the KA‐induced neurotoxicity. Nevertheless, KA‐induced α‐synuclein aggregation was not affected in the Atg7 siRNA‐transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA‐induced autophagy‐lysosomal activation by reducing KA‐induced increases in LC3‐II, lysosomal‐associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA‐induced mitochondria loss was prevented in the melatonin‐treated mice. At the same time, melatonin reduced KA‐increased HO‐1 levels and α‐synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α‐synuclein monomers and aggregates. The anti‐apoptotic effect of melatonin was demonstrated by attenuating KA‐induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA‐induced neurotoxicity may be mediated by autophagy and α‐synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA‐induced autophagy and a subsequent mitochondrial loss as well as reducing α‐synuclein aggregation by enhancing α‐synuclein ubiquitination in the CNS.
Daily variation of oral malodour and related factors in community‐dwelling elderly Thai
Authors: Samnieng Patcharaphol , Ueno Masayuki , Shinada Kayoko , Zaitsu Takashi , Kawaguchi Yoko
Published: December 2011

doi: 10.1111/j.1741‐2358.2011.00593.x

Daily variation of oral malodour and related factors in community‐dwelling elderly Thai

Objectives:  The purposes of this study were (i) to estimate the prevalence of oral malodour, (ii) to evaluate the daily variation of oral malodour and (iii) to assess associations of volatile sulphur compound (VSC) concentrations with socio‐demographics, health behaviours and oral health status in community‐dwelling elderly Thai.

Methods:  The subjects were 428 dentate elderly people (67.6 ± 5.6 years) living in Phitsaulok, Thailand. Information on their socio‐demographics, general health and health behaviours was obtained by a questionnaire. Their dental condition, periodontal status and tongue coating were clinically examined. Their flow rates and the pH of unstimulated saliva were also assessed. Oral malodour was measured at four different times of day using an Oral Chroma™.

Results:  The proportions of subjects diagnosed with oral malodour using the thresholds of H2S, CH3SH and (CH3)2S were 60.5%, 62.9% and 80.7%, respectively. Concentrations of H2S showed significant daily variation. Linear regression analysis demonstrated the following significant associations: (i) oral malodour from H2S and thickness of the tongue coating, (ii) oral malodour from CH3SH and periodontal pocket depth of 5 mm or more and the presence of gingival bleeding and (iii) oral malodour from (CH3)2S and systemic disease, medications and thickness of the tongue coating.

Discussion:  Oral malodour was shown to be prevalent among the elderly. Daily variation was observed in the concentration of H2S. Tongue coating, periodontal disease, systemic diseases and medications were related to oral malodour. Therefore, these factors should be taken into consideration in oral malodour treatment and prevention programmes for the elderly.
Insight into Selectivity of Peptidomimetic Inhibitors with Modified Statine Core for Plasmepsin II of Plasmodium falciparum over Human Cathepsin D
Authors: Dali Brice , Keita Melalie , Megnassan Eugene , Frecer Vladimir , Miertus Stanislav
Published: December 2011

Plasmepsin II (PlmII), an aspartic protease expressed in the food vacuole of Plasmodium falciparum (pf), cleaves the hemoglobin of the host during the erythrocytic stage of the parasite life cycle. Various peptidomimetic inhibitors of PlmII reported so far discriminate poorly between the drug target and aspartic proteases of the host organism, e.g., human cathepsin D (hCatD). hCatD is a protein digestion enzyme and signaling molecule involved in a variety of physiological processes; therefore, inhibition of hCatD by PlmII inhibitors may lead to pathophysiological conditions. In this study, binding of PlmII inhibitors has been modeled using the crystal structures of pfPlmII and hCatD complexes to gain insight into structural requirements underlying the target selectivity. A series of 26 inhibitors were modeled in the binding clefts of the pfPlmII and hCatD to establish QSAR models of the protease inhibition. In addition, 3D‐QSAR pharmacophore models were generated for each enzyme. It was concluded that the contributions of the P2 and P3′ residues to the inhibitor’s binding affinity are responsible for the target selectivity. Based on these findings, new inhibitor candidates were designed with predicted inhibition constants reaching 0.2 nm and selectivity index (S.I.) =  > 1200.
DEBTOR: debt evaluation, bench‐marking and tracking – a water debt management tool to address UK water debt
Authors: Clarke Martin , Boden Pete , McDonald Adrian
Published: December 2011

UK water debt has increased rapidly and has become a significant management issue for most water companies, constraining investment in necessary environmental interventions. Debt is characterised as debt penetration (percentage of customers in debt) and debt intensity (average size of debt per indebted customer). Actual debt characteristics in a water company can be plotted by intensity and penetration to demonstrate performance differences between companies, changes over time and performance relative to national norms. Using the relationships between debt and deprivation, the expected debt performance can be plotted. Using the expected position as a benchmark, the company performance can be evaluated and the remedial strategies can be targeted (if required) towards reduction of frequency and size of debt. The distance between actual and expected values is used as a metric of the requirement for additional debt management investment. Examples of these debtor plots for a range of anonymous companies are presented.