bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic Erosive Dislocation of Radial Head Resulting from Elbow Pyarthrosis—A Rare Delayed Complication of Fracture Dislocation of Elbow
Authors: Cheul<-Hang Sin , Yuen-Fai Leung , Pui-Seung Ip Shirley , Wing-Yuk Ip
Published: December 2011

We present a case of elbow injury with chronic infection resulting in open dislocation of radial head together with elbow instability. The principle of treatment of elbow dislocation and the importance of ligamentous integrity would be discussed.
Flow of a spherical capsule in a pore with circular or square cross-section
Authors: Hu X.-Q. , Salsac A.-V. , Barthès-Biesel D.
Published: December 2011

The motion and deformation of a spherical elastic capsule freely flowing in a pore of comparable dimension is studied. The thin capsule membrane has a neo-Hookean shear softening constitutive law. The three-dimensional fluid–structure interactions are modelled by coupling a boundary integral method (for the internal and external fluid motion) with a finite element method (for the membrane deformation). In a cylindrical tube with a circular cross-section, the confinement effect of the channel walls leads to compression of the capsule in the hoop direction. The membrane then tends to buckle and to fold as observed experimentally. The capsule deformation is three-dimensional but can be fairly well approximated by an axisymmetric model that ignores the folds. In a microfluidic pore with a square cross-section, the capsule deformation is fully three-dimensional. For the same size ratio and flow rate, a capsule is more deformed in a circular than in a square cross-section pore. We provide new graphs of the deformation parameters and capsule velocity as a function of flow strength and size ratio in a square section pore. We show how these graphs can be used to analyse experimental data on the deformation of artificial capsules in such channels.
Regimes of two-dimensionality of decaying shallow axisymmetric swirl flows with background rotation
Authors: Duran-Matute M. , Kamp L. P. J. , Trieling R. R. , van Heijst G. J. F.
Published: December 2011

Both background rotation and small depths are said to enforce the two-dimensionality of flows. In the current paper, we describe a systematic study of the two-dimensionality of a shallow monopolar vortex subjected to background rotation. Using a perturbation analysis of the Navier–Stokes equations for small aspect ratio $\delta = H/ L$ (with $H$ the fluid depth and $L$ a typical radial length scale of the vortex), we found nine different regimes in the parameter space where the flow is governed to lowest order by different sets of equations. From the properties of these sets of equations, it was determined that the flow can be considered as quasi-two-dimensional in only five of the nine regimes. The scaling of the velocity components as given by these sets of equations was compared with results from numerical simulations to find the actual boundaries of the different regimes in the parameter space (${h}_{\mathit{Ek}} , {h}_{\mathit{Re}} $), where ${h}_{\mathit{Ek}} $ is the Ekman boundary layer thickness and ${h}_{\mathit{Re}} $ is the equivalent boundary layer thickness for a monopolar vortex without background rotation. Even though background rotation and small depths do promote the two-dimensionality of flows independently, the combination of these two characteristics does not necessarily have that same effect.
An International Comparison of Capital Structure and Debt Maturity Choices
Authors: Fan Joseph P. H. , Titman Sheridan , Twite Garry
Published: December 2011

This study examines how the institutional environment influences capital structure and debt maturity choices of firms in 39 developed and developing countries. We find that a country’s legal and tax system, corruption, and the preferences of capital suppliers explain a significant portion of the variation in leverage and debt maturity ratios. Specifically, firms in more corrupt countries and those with weaker laws tend to use more debt, especially short-term debt; explicit bankruptcy codes and deposit insurance are associated with higher leverage and more long-term debt. More debt is used in countries where there is a greater tax gain from leverage.
Pituitary volume, stress reactivity and genetic risk for psychotic disorder
Authors: Habets P. , Collip D. , Myin-Germeys I. , Gronenschild E. , van Bronswijk S. , Hofman P. , Lataster T. , Lardinois M. , Nicolson N. A. , van Os J. , Marcelis M.
Published: December 2011

Background

Hypothalamic–pituitary–adrenal (HPA) axis hyperactivity, associated with increased pituitary volume, may mediate observed alterations in stress reactivity in patients with psychotic disorder. We examined the association between pituitary volume, real-life stress reactivity and genetic liability for psychotic disorder.

Method

Pituitary volumes were derived from magnetic resonance imaging (MRI) scans of 20 patients with psychotic disorder, 37 non-psychotic siblings of these patients, and 32 controls. The Experience Sampling Method (ESM) was used to measure emotional stress reactivity [changes in negative affect (NA) associated with daily life stress] in the three groups, and biological stress reactivity (changes in cortisol associated with daily life stress) in siblings and controls. Interactions between group, stress and pituitary volume in models of NA and cortisol were examined.

Results

Groups did not differ in pituitary volume. Patients showed significantly higher emotional stress reactivity than siblings and controls. In addition, emotional stress reactivity increased with increasing pituitary volume to a greater degree in patients than in controls and siblings. Siblings had higher cortisol levels than controls but did not show increased cortisol reactivity to stress. There was no interaction between pituitary volume, stress and group in the model of cortisol.

Conclusions

Higher pituitary volume was associated with increased emotional stress reactivity in patients with psychotic disorder, siblings and controls. The association was significantly stronger in the patient group, suggesting a process of progressive sensitization mediating clinical outcome.
Bread provisioning and retail dynamics in the southern Low Countries: the bakers of Leuven, 1600–1800
Authors: DEWILDE BRECHT , POUKENS JOHAN
Published: December 2011

The central argument of this article is that current historical research into early modern retail growth and practices has focused too narrowly on the retail of durables (perhaps with the exception of colonial groceries) and on retailers' guilds. The role of food-producing and/or food-retailing guilds hitherto has received less attention. Research into retail practices has not connected to an older (but still lively) research tradition in which the consumption of basic foodstuffs received the bulk of attention. We argue that if selling bread is approached as a ‘system of provision’, competing retail circuits and the different ways in which subsequent subsistence crises affected each of those circuits offer an additional explanation (next to well-documented changes in demand) for the inclusion of other basic provisions, colonial groceries, clothing, and even durables in the assortment of traditional food-producing and food-retailing guild masters, in this case the Leuven bakers.
Large wood storage in streams of the Eastern Italian Alps and the relevance of hillslope processes
Authors: Rigon E. , Comiti F. , Lenzi M. A.
Published: December 2011

An understanding of the dynamics of large wood (LW) in mountain channels provides the basis for evaluating natural morphological patterns as well as managing potentially hazardous wood transport during flood events. Few studies have investigated the distribution of LW in managed streams of the Alps across a wide spatial scale. This paper presents extensive field measurements of LW storage and channel morphology carried out in 13 channels of the Eastern Italian Alps with drainage areas ranging from 1.2 to 70 km2, mean bed slope between 0.03 and 0.38, and channel width between 2 and 20 m. More than 9000 LW elements were measured in the 33 reaches surveyed. A geostatistical, geographic information system (GIS)‐based model for wood recruitment from hillslope instabilities was also developed and applied to the study basin. LW storage in the study channels results as being much lower than in seminatural basins of comparable size and climate, and only basins characterized by extensive mass wasting processes contain high wood loads with relevant morphological consequences. The statistical analysis of LW storage at the reach scale indicates that unit stream power is apparently the most significant hydromorphological factor influencing LW storage, in agreement with studies in other world regions. However, we argue that the effect of unit stream power on LW storage is not only linked to flow transport capacity but also derives from its association with LW supply and valley morphology. Both the GIS model and statistical tests on field data indicate that hillslope instabilities connected to the channel network dominate the LW recruitment volume and the distribution of in‐channel wood storage.
Aerosol impacts on clouds and precipitation in eastern China: Results from bin and bulk microphysics
Authors: Fan Jiwen , Leung L. Ruby , Li Zhanqing , Morrison Hugh , Chen Hongbin , Zhou Yuquan , Qian Yun , Wang Yuan
Published: December 2011

Using the Weather Research and Forecasting model coupled with a spectral‐bin microphysics (“SBM”) and measurements from the Atmospheric Radiation Measurement Mobile Facility field campaign in China (AMF‐China), the authors examine aerosol indirect effects (AIE) in the typical cloud regimes of the warm and cold seasons in Southeast China: deep convective clouds (DCC) and stratus clouds (SC), respectively. Comparisons with a two‐moment bulk microphysics (“Bulk”) are performed to gain insights for improving bulk schemes in estimating AIE in weather and climate simulations. For the first time, measurements of aerosol and cloud properties acquired in China are used to evaluate model simulations to better understand aerosol impact on clouds in the southeast of China. It is found that changes in cloud condensation nuclei (CCN) concentration significantly change the timing of storms, the spatial and temporal distributions of precipitation, the frequency distribution of precipitation rate, as well as cloud base and top heights for the DCC, but not for the SC. Increasing CCN increases cloud droplet number (Nc) and mass concentrations, decreases raindrop number concentration, and delays the onset of precipitation. Compared with SBM, Bulk predicts much higher Ncand the opposite CCN effects on convection and heavy rain, stemming from the fixed CCN prescribed in Bulk. CCN have a significant effect on ice microphysical properties with SBM but not Bulk and different condensation/deposition freezing parameterizations employed could be the main reason. This study provided insights to further improve the bulk scheme to better account for aerosol‐cloud interactions in regional and global climate simulations, which will be the focus for a follow‐on paper.
Stability and resilience of seagrass meadows to seasonal and interannual dynamics and environmental stress
Authors: Carr Joel A. , D'Odorico Paolo , McGlathery Karen J. , Wiberg Patricia L.
Published: December 2011

Shallow coastal bays provide habitat for diverse fish and invertebrate populations and are an important source of sediment for surrounding marshes. The sediment dynamics of these bays are strongly affected by seagrass meadows, which limit sediment resuspension, thereby providing a more favorable light environment for their own survival and growth. Due to this positive feedback between seagrass and light conditions, it has been suggested that bare sediment and seagrass meadows are potential alternate stable states of the benthos in shallow coastal bays. To investigate the stability and resilience of seagrass meadows subjected to variation in environmental conditions (e.g., light, temperature), a coupled model of vegetation–sediment–water flow interactions and vegetation growth was developed. The model was used to examine the effect of dynamically varying seasonal and interannual seagrass density on sediment resuspension, water column turbidity, and the subsequent light environment on hourly time steps and then run over decadal time scales. A daily growth model was designed to capture both belowground biomass and the growth and senescence of aboveground biomass structural components (e.g., leaves and stems). This allowed us to investigate how the annual and seasonal variability in shoot and leaf density within a meadow affects the strength of positive feedbacks between seagrass and their light environment. The model demonstrates both the emergence of bistable behavior from 1.6 to 1.8 m mean sea level due to the strength of the positive feedback, as well as the limited resilience of seagrass meadows within this bistable range.
Plant patch hydrodynamics in streams: Mean flow, turbulence, and drag forces
Authors: Siniscalchi Fabio , Nikora Vladimir I. , Aberle Jochen
Published: December 2011

This paper investigates the effects of a finite‐size vegetation patch on flow turbulence, variations in drag forces experienced by individual plants within the patch, and flow‐drag interrelations. The experiments were conducted in a 32 m long laboratory flume with a 2.8 m long artificial patch. The plants were arranged to form a staggered pattern and three flow scenarios were tested. Velocities were recorded with an acoustic doppler velocimeter, whereas specifically designed devices were used to simultaneously measure the drag forces acting on nine plants within the patch. For all studied cases, the results show zones of increased turbulent energy close to the leading edge and along the patch canopy top, where turbulence shear production is enhanced. Zones of negative Reynolds stresses −u′w′ are found inside the patch and they reflect the influence of plant morphology, which affects the shape of the longitudinal velocity profile and associated turbulent fluxes. Modifications to the power spectral densities of velocity by the plants indicate the emergence of two plant‐induced mechanisms of energy production, which are most likely related to the wake turbulence and shear layer turbulence. Drag fluctuations appear to be correlated with the velocity field, with this correlation being especially profound at the highest‐studied flow rate. The data suggest that the highlighted correlation stems from flow‐plant interactions at the top of the vegetation canopy, likely due to the presence of large three‐dimensional coherent structures.
An improved Greengenes taxonomy with explicit ranks for ecological and evolutionary analyses of bacteria and archaea
Authors: McDonald Daniel , Price Morgan N , Goodrich Julia , Nawrocki Eric P , DeSantis Todd Z , Probst Alexander , Andersen Gary L , Knight Rob , Hugenholtz Philip
Published: December 2011

Reference phylogenies are crucial for providing a taxonomic framework for interpretation of marker gene and metagenomic surveys, which continue to reveal novel species at a remarkable rate. Greengenes is a dedicated full-length 16S rRNA gene database that provides users with a curated taxonomy based on de novo tree inference. We developed a ‘taxonomy to tree’ approach for transferring group names from an existing taxonomy to a tree topology, and used it to apply the Greengenes, National Center for Biotechnology Information (NCBI) and cyanoDB (Cyanobacteria only) taxonomies to a de novo tree comprising 408 315 sequences. We also incorporated explicit rank information provided by the NCBI taxonomy to group names (by prefixing rank designations) for better user orientation and classification consistency. The resulting merged taxonomy improved the classification of 75% of the sequences by one or more ranks relative to the original NCBI taxonomy with the most pronounced improvements occurring in under-classified environmental sequences. We also assessed candidate phyla (divisions) currently defined by NCBI and present recommendations for consolidation of 34 redundantly named groups. All intermediate results from the pipeline, which includes tree inference, jackknifing and transfer of a donor taxonomy to a recipient tree (tax2tree) are available for download. The improved Greengenes taxonomy should provide important infrastructure for a wide range of megasequencing projects studying ecosystems on scales ranging from our own bodies (the Human Microbiome Project) to the entire planet (the Earth Microbiome Project). The implementation of the software can be obtained from http://sourceforge.net/projects/tax2tree/.
On the effects of high temperature and high pressure on the hydrogen solubility in rhenium
Authors: Scheler Thomas , Degtyareva Olga , Gregoryanz Eugene
Published: December 2011

In situ x-ray diffraction experiments on rhenium hydride compressed up to 46 GPa reveal a hydrogen solubility (x) significantly larger than the previously assumed saturation limit of x ∼ 0.38(4). In the layered anti-CdI2-type structure of rhenium hydride, the hydrogen solubility was found to increase to x ∼ 0.5 at 15 GPa over time. When heated to temperatures above 420 K at pressures above 23 GPa, rhenium hydride undergoes an isomorphous phase transition into the NiAs-type structure accompanied by an increase in hydrogen solubility to x ∼ 0.85. The formation of fully stoichiometric rhenium hydride is discussed.
Solvent response of mixed polymer brushes
Authors: Gong Kai , Chapman Walter G.
Published: December 2011

We have performed classical density functional theory calculations to study the behavior of mixed polymer brushes tethered to a planar surface. We assume no lateral segregation of the polymer at the grafting density studied and consider an implicit solvent. For a binary mixture of short and long athermal polymer chains, the short chain is compressed while the long chain is stretched compared with corresponding pure polymer chains at the same grafting density, which is consistent with simulation. This results from configurational entropy effects. Furthermore, we add a mean-field interaction for each polymer brush to simulate their different response towards a solvent. The long chain is forced to dislike the solvent more than the short chain. Through the interplay between the solvent effects and configurational entropy effects, a switch of the polymer brush surface (or outer) layer is found with increasing chain length of the long chain. The transition chain length (long chain) increases with increasing the solvent selectivity, and decreases with increasing the grafting density of the long chain. These results can provide guidance for the design of smart materials based on mixed polymer brushes.
Effect of microhydration on the guanidinium⋯benzene interaction
Authors: Cabaleiro-Lago Enrique M. , Rodríguez-Otero Jesús , Peña-Gallego Ángeles
Published: December 2011

The effect of microhydration on the interaction of guanidinium cation with benzene has been studied by employing ab initio calculations. Four different structural arrangements were considered for the guanidinium⋯benzene interaction to which up to six water molecules were added. T-shaped structures are usually the most stable, but as water molecules are included the energy differences with the parallel structures decrease, reaching a point where parallel complexes are even more stable than T-shaped ones. Therefore, the inclusion of water molecules promotes a change in the structure of the cation⋯π contact. The analysis reveals that these stability changes are more related with the structure of the hydrating water molecules than to a modulation of the cation⋯π interaction. Already with three water molecules, one water molecule in the T-shaped complex has to be located in the second solvation shell, whereas in parallel structures this occurs with four water molecules. As a consequence energy differences among structures decrease. The calculations show that the nature of the interaction is almost unaffected in T-shaped structures, whereas an important dispersion increment is observed in parallel ones, though its overall effect is small.
Electronic interaction and bipolar resistive switching in copper oxide-multilayer graphene hybrid interface: Graphene as an oxygen ion storage and blocking layer
Authors: Singh Bharti , Mehta B. R. , Govind  , Feng X. , Müllen Klaus
Published: December 2011

This study reports a bipolar resistive switching device based on copper oxide (CuO)-multilayer graphene (MLG) hybrid interface in complete contrast to the ohmic and rectifying characteristics of junctions based on individual MLG and CuO layers. The observed shift and the occurrence of additional O1s, Cu2p, and C1s core level peaks indicate electronic interaction at the hybrid interfacial layer. Large changes in the resistive switching parameters on changing the ambient conditions from air to vacuum establish the important role of MLG as oxygen ion storage and blocking layer towards the observed resistive switching effect.
Junction temperature measurement of light emitting diode by electroluminescence
Authors: He S. M. , Luo X. D. , Zhang B. , Fu L. , Cheng L. W. , Wang J. B. , Lu W.
Published: December 2011

Junction temperature (JT) is a key parameter of the performance and lifetime of light emitting diodes (LEDs). In this paper, a mobile instrument system has been developed for the non-contact measurement of JTs of LED under LabVIEW control. The electroluminescence (EL) peak shift of the LED is explored to measure the JT. Commercially available high power blue LEDs are measured. A linear relation between emission peak shift and JT is found. The accuracy of the JT is about 1 °C determined by the precision of the emission peak shift, ±0.03 nm, at 3σ standard deviation for blue LED. Using this system, on-line temperature rise curves of LED lamps are determined.
Reorganization of Au nanoparticle Langmuir-Blodgett films on wet chemically passivated Si(001) surfaces
Authors: Kundu Sarathi , Bal J. K.
Published: December 2011

Growth of dodecanethiol-encapsulated Au nanoparticles on differently terminated (OH-, H-, or Br-terminated) Si(001) substrates by Langmuir-Blodgett method at a constant monolayer surface pressure and their out-of-plane structural modification with time have been investigated. As the substrates have different gradations in the hydrophilic/hydrophobic nature, three different out-of-plane structures have been formed. On H-terminated Si (hydrophobic surface), a fluctuating monolayer of Au nanoparticles has been formed, whereas on Br- (coexistence of hydrophilic and hydrophobic surfaces) and OH-terminated Si (hydrophilic surfaces), trilayer of Au nanoparicles have been formed, but the top layer coverage is more for the OH-terminated Si. The growth of Au nanoparticles on H-terminated Si is similar to the Frank-van der Marwe mode, whereas on Br- and OH-terminated Si, the growth is similar to the Stranski-Krastanov mode. These three different structures modify with time and finally become a thicker monolayer of high density, and positions of naoparticles within the monolayer become random. AFM images of the films also show that positions of the Au nanoparticles are random. Density of the final layer becomes maximum on OH-terminated Si and minimum on H-terminated Si, whereas it becomes intermediate on Br-terminated Si. Reorganization thus helps to obtain nanostructures of tunable nanoparticle density.
Continuous-wave cascaded-harmonic generation and multi-photon Raman lasing in lithium niobate whispering-gallery resonators
Authors: Moore Jeremy , Tomes Matthew , Carmon Tal , Jarrahi Mona
Published: December 2011

We report experimental demonstration of continuous-wave cascaded-harmonic generation and Raman lasing in a millimeter-scale lithium niobate whispering-gallery resonator pumped at a telecommunication-compatible infrared wavelength. Intensity enhancement through multiple recirculations in the whispering-gallery resonator and quasi phase-matching through a nonuniform crystal poling enable simultaneous cascaded-harmonic generation up to the fourth-harmonic accompanied by stimulated Raman, two-photon, three-photon, and four-photon Raman scattering corresponding the molecular vibrational wavenumbers 632 and 255 cm−1 in z-cut lithium niobate at pump power levels as low as 200 mW. We demonstrate simultaneous cascaded-harmonic generation and Raman lasing by observing the spectrum of the scattered light from the resonator and by capturing the image of the decoupled light from the resonator on a camera.
Adoption Patterns of Occupational Pensions in Germany
Authors: Burger Csaba
Published: December 2011

The withdrawal of the welfare states from pensions underscores the need for a better understanding of the spatial characteristics of adoption processes in the case of financial innovations. In 2001 the German pension reform reduced publicly provided pensions, and introduced subsidised, voluntary occupational plans to replace the loss in retirement income. This paper looks at the spatial and temporal adoptions of the newly created occupational pensions by analysing a unique, proprietary database, containing data on 12 000 employers and 286 000 employees working in the German metal and electric industry. The study identifies metropolitan/nonmetropolitan, East–West, and further geographical differences in the employers' timing to adopt, which in turn influences employees' decisions to enrol. Differences are identified among employee-level adoptions depending on the employers' timing and further, individual-level factors. The results emphasise the importance of geography in the transformation of old-age finances in the German welfare state.
Genomic anatomy of
Escherichia coli
O157:H7 outbreaks
Authors: Eppinger Mark , Mammel Mark K. , Leclerc Joseph E. , Ravel Jacques , Cebula Thomas A.
Published: December 2011

The rapid emergence of
Escherichia coli
O157:H7 from an unknown strain in 1982 to the dominant hemorrhagic
E. coli
serotype in the United States and the cause of widespread outbreaks of human food-borne illness highlights a need to evaluate critically the extent to which genomic plasticity of this important enteric pathogen contributes to its pathogenic potential and its evolution as well as its adaptation in different ecological niches. Aimed at a better understanding of the evolution of the
E. coli
O157:H7 pathogenome, the present study presents the high-quality sequencing and comparative phylogenomic analysis of a comprehensive panel of 25
E. coli
O157:H7 strains associated with three nearly simultaneous food-borne outbreaks of human disease in the United States. Here we present a population genetic analysis of more than 200 related strains recovered from patients, contaminated produce, and zoonotic sources. High-resolution phylogenomic approaches allow the dynamics of pathogenome evolution to be followed at a high level of phylogenetic accuracy and resolution. SNP discovery and study of genome architecture and prophage content identified numerous biomarkers to assess the extent of genetic diversity within a set of clinical and environmental strains. A total of 1,225 SNPs were identified in the present study and are now available for typing of the
E. coli
O157:H7 lineage. These data should prove useful for the development of a refined phylogenomic framework for forensic, diagnostic, and epidemiological studies to define better risk in response to novel and emerging
E. coli
O157:H7 resistance and virulence phenotypes.
Measurement of the ground-state distributions in bistable mechanically interlocked molecules using slow scan rate cyclic voltammetry
Authors: Fahrenbach Albert C. , Barnes Jonathan C. , Li Hao , Benítez Diego , Basuray Ashish N. , Fang Lei , Sue Chi-Hau , Barin Gokhan , Dey Sanjeev K. , Goddard William A. , Stoddart J. Fraser
Published: December 2011

In donor–acceptor mechanically interlocked molecules that exhibit bistability, the relative populations of the translational isomers—present, for example, in a bistable [2]rotaxane, as well as in a couple of bistable [2]catenanes of the donor–acceptor vintage—can be elucidated by slow scan rate cyclic voltammetry. The practice of transitioning from a fast scan rate regime to a slow one permits the measurement of an intermediate redox couple that is a function of the equilibrium that exists between the two translational isomers in the case of all three mechanically interlocked molecules investigated. These intermediate redox potentials can be used to calculate the ground-state distribution constants,
K
. Whereas, (i) in the case of the bistable [2]rotaxane, composed of a dumbbell component containing
π
-electron-rich tetrathiafulvalene and dioxynaphthalene recognition sites for the ring component (namely, a tetracationic cyclophane, containing two
π
-electron-deficient bipyridinium units), a value for
K
of 10 ± 2 is calculated, (ii) in the case of the two bistable [2]catenanes—one containing a crown ether with tetrathiafulvalene and dioxynaphthalene recognition sites for the tetracationic cyclophane, and the other, tetrathiafulvalene and butadiyne recognition sites—the values for
K
are orders (one and three, respectively) of magnitude greater. This observation, which has also been probed by theoretical calculations, supports the hypothesis that the extra stability of one translational isomer over the other is because of the influence of the enforced side-on donor–acceptor interactions brought about by both
π
-electron-rich recognition sites being part of a macrocyclic polyether.
Timing of centrosome separation is important for accurate chromosome segregation
Authors: Silkworth William T. , Nardi Isaac K. , Paul Raja , Mogilner Alex , Cimini Daniela
Published: December 2011

Spindle assembly, establishment of kinetochore attachment, and sister chromatid separation must occur during mitosis in a highly coordinated fashion to ensure accurate chromosome segregation. In most vertebrate cells, the nuclear envelope must break down to allow interaction between microtubules of the mitotic spindle and the kinetochores. It was previously shown that nuclear envelope breakdown (NEB) is not coordinated with centrosome separation and that centrosome separation can be either complete at the time of NEB or can be completed after NEB. In this study, we investigated whether the timing of centrosome separation affects subsequent mitotic events such as establishment of kinetochore attachment or chromosome segregation. We used a combination of experimental and computational approaches to investigate kinetochore attachment and chromosome segregation in cells with complete versus incomplete spindle pole separation at NEB. We found that cells with incomplete spindle pole separation exhibit higher rates of kinetochore misattachments and chromosome missegregation than cells that complete centrosome separation before NEB. Moreover, our mathematical model showed that two spindle poles in close proximity do not “search” the entire cellular space, leading to formation of large numbers of syntelic attachments, which can be an intermediate stage in the formation of merotelic kinetochores.
Lidocaine Metabolites Inhibit Glycine Transporter 1
Authors: Werdehausen Robert , Kremer David , Brandenburger Timo , Schlösser Lukas , Jadasz Janusz , Küry Patrick , Bauer Inge , Aragón Carmen , Eulenburg Volker , Hermanns Henning
Published: December 2011

Background

Lidocaine exerts antinociceptive effects when applied systemically. The mechanisms are not fully understood but glycinergic mechanisms might be involved. The synaptic glycine concentration is controlled by glycine transporters. Whereas neurons express two types of glycine transporters, astrocytes specifically express glycine transporter 1 (GlyT1). This study focuses on effects of lidocaine and its major metabolites on GlyT1 function.

Methods

The effects of lidocaine and its metabolites monoethylglycinexylidide (MEGX), glycinexylidide, and N-ethylglycine on GlyT1 function were investigated in uptake experiments with [¹⁴C]-labeled glycine in primary rat astrocytes. Furthermore, the effect of lidocaine and its metabolites on glycine-induced currents were investigated in GlyT1-expressing Xenopus laevis oocytes.

Results

Lidocaine reduced glycine uptake only at toxic concentrations. The metabolites MEGX, glycinexylidide, and N-ethylglycine, however, significantly reduced glycine uptake (P < 0.05). Inhibition of glycine uptake by a combination of lidocaine with its metabolites at a clinically relevant concentration was diminished with increasing extracellular glycine concentrations. Detailed analysis revealed that MEGX inhibits GlyT1 function (P < 0.05), whereas N-ethylglycine was identified as an alternative GlyT1 substrate (EC₅₀ = 55 μM).

Conclusions

Although lidocaine does not function directly on GlyT1, its metabolites MEGX and N-ethylglycine [corrected] were shown to inhibit GlyT1-mediated glycine uptake by at least two different mechanisms. Whereas N-ethylglycine [corrected] was demonstrated to be an alternative GlyT1 substrate, MEGX was shown to inhibit GlyT1 activity in both primary astrocytes and in GlyT1-expressing Xenopuslaevis oocytes at clinically relevant concentrations. These findings provide new insights into the possible mechanisms for the antinociceptive effect of systemic lidocaine.
A novel reassortant canine H3N1 influenza virus between pandemic H1N1 and canine H3N2 influenza viruses in Korea
Authors: Song Daesub , Moon Hyoung-Joon , An Dong-Jun , Jeoung Hye-Young , Kim Hyekwon , Yeom Min-Joo , Hong Minki , Nam Jeong-Hyun , Park Seong-Jun , Park Bong-Kyun , Oh Jin-Sik , Song Manki , Webster Robert G. , Kim Jeong-Ki , Kang Bo-Kyu
Published: December 2011

During recent canine influenza surveillance in South Korea, a novel H3N1 canine influenza virus (CIV) that is a putative reassortant between pandemic H1N1 2009 and H3N2 CIVs was isolated. Genetic analysis of eight genes of the influenza virus revealed that the novel H3N1 isolate presented high similarities (99.1–99.9 %) to pandemic influenza H1N1, except for in the haemagglutinin (HA) gene. The HA gene nucleotide sequence of the novel CIV H3N1 was similar (99.6 %) to that of CIV H3N2 isolated in Korea and China. Dogs infected with the novel H3N1 CIV did not show any notable symptoms, in contrast to dogs infected with H3N2 CIV. Despite no visible clinical signs of disease, nasal shedding of virus was detected and the infected dogs presented mild histopathological changes.
Quercetin Protects Primary Human Osteoblasts Exposed to Cigarette Smoke through Activation of the Antioxidative Enzymes HO-1 and SOD-1
Authors: Braun Karl F. , Ehnert Sabrina , Freude Thomas , Egaña José T. , Schenck Thilo L. , Buchholz Arne , Schmitt Andreas , Siebenlist Sebastian , Schyschka Lilianna , Neumaier Markus , Stöckle Ulrich , Nussler Andreas K.
Published: December 2011

Smokers frequently suffer from impaired fracture healing often due to poor bone quality and stability. Cigarette smoking harms bone cells and their homeostasis by increased formation of reactive oxygen species (ROS). The aim of this study was to investigate whether Quercetin, a naturally occurring antioxidant, can protect osteoblasts from the toxic effects of smoking. Human osteoblasts exposed to cigarette smoke medium (CSM) rapidly produced ROS and their viability decreased concentration- and time-dependently. Co-, pre- and postincubation with Quercetin dose-dependently improved their viability. Quercetin increased the expression of the anti-oxidative enzymes heme-oxygenase- (HO-) 1 and superoxide-dismutase- (SOD-) 1. Inhibiting HO-1 activity abolished the protective effect of Quercetin. Our results demonstrate that CSM damages human osteoblasts by accumulation of ROS. Quercetin can diminish this damage by scavenging the radicals and by upregulating the expression of HO-1 and SOD-1. Thus, a dietary supplementation with Quercetin could improve bone matter, stability and even fracture healing in smokers.
Genome-wide analysis of retrogene polymorphisms in Drosophila melanogaster
Authors: Schrider Daniel R. , Stevens Kristian , Cardeño Charis M. , Langley Charles H. , Hahn Matthew W.
Published: December 2011

Gene duplication via retrotransposition has been shown to be an important mechanism in evolution, affecting gene dosage and allowing for the acquisition of new gene functions. Although fixed retrotransposed genes have been found in a variety of species, very little effort has been made to identify retrogene polymorphisms. Here, we examine 37 Illumina-sequenced North American Drosophila melanogaster inbred lines and present the first ever data set and analysis of polymorphic retrogenes in Drosophila. We show that this type of polymorphism is quite common, with any two gametes in the North American population differing in the presence or absence of six retrogenes, accounting for ∼13% of gene copy-number heterozygosity. These retrogenes were identified by a straightforward method that can be applied using any type of DNA sequencing data. We also use a variant of this method to conduct a genome-wide scan for intron presence/absence polymorphisms, and show that any two chromosomes in the population likely differ in the presence of multiple introns. We show that these polymorphisms are all in fact deletions rather than intron gain events present in the reference genome. Finally, by leveraging the known location of the parental genes that give rise to the retrogene polymorphisms, we provide direct evidence that natural selection is responsible for the excess of fixations of retrogenes moving off of the X chromosome in Drosophila. Further efforts to identify retrogene and intron presence/absence polymorphisms will undoubtedly improve our understanding of the evolution of gene copy number and gene structure.
Assessment of Infectivity Using a Herpesvirus Saimiri (HVS) Recombinant that Expresses HVS–GFP: Figure 1.
Authors: Whitehouse Adrian
Published: December 2011

Herpesvirus saimiri (HVS) is capable of infecting a wide range of human cell types with high efficiency. The viral genome persists as high-copy-number, circular, nonintegrated episomes that segregate to progeny on cell division. This allows HVS-based vectors to transduce stably a dividing cell population and provide sustained transgene expression for an extended period of time both in vitro and in vivo. Moreover, the insertion of a bacterial artificial chromosome (BAC) cassette into the HVS genome simplifies the incorporation of large amounts of heterologous DNA for gene delivery. These properties offer characteristics similar to that of an artificial chromosome combined with an efficient delivery system. This protocol describes the use of an HVS recombinant virus expressing green fluorescent protein (GFP) (HVS–GFP) to assess the infectivity of a specific cell line.
Illumination for Worm Tracking and Behavioral Imaging: Figure 1.
Authors: Yemini Eviatar , Kerr Rex A. , Schafer William R.
Published: December 2011

Neurobiological research in genetically tractable organisms relies heavily on robust assays for behavioral phenotypes. The simple body plan of the nematode Caenorhabditis elegans makes it particularly amenable to the use of automated microscopy and image analysis to describe behavioral patterns quantitatively. This protocol provides an approach for obtaining uniform illumination during worm tracking. Good lighting can be more of an art than a science. Once the system is set up, it will be necessary to play with it, testing the results after each adjustment to ensure that the analysis software is able to clearly identify the worm and its boundaries. Although the protocol was developed for use in a single-worm tracker, it addresses factors important for the generation of reproducible, standardized images in all systems.
Review article: rifabutin in the treatment of refractory Helicobacter pylori infection
Authors: Gisbert J. P. , Calvet X.
Published: December 2011

Aliment Pharmacol Ther 2012; 35: 209–221

Background  Even with the current most effective treatment regimens, a relevant proportion of patients will fail to eradicate Helicobacter pylori infection.

Aim  To evaluate the role of rifabutin in the treatment of H. pylori infection.

Methods  Bibliographical searches were performed in MEDLINE. Data on the efficacy of rifabutin‐containing regimens on H. pylori eradication were combined and meta‐analysed using the generic inverse variance method.

Results  Rifabutin shows good in vitro activity against H. pylori. Mean H. pylori rifabutin resistance rate (calculated from 11 studies including 2982 patients) was 1.3% (95% confidence interval = 0.9–1.7%). When only studies including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.6%). On the other hand, higher values of rifabutin resistance were calculated (1.59%) when only post‐treatment patients were considered. Overall, mean H. pylori eradication rate (intention‐to‐treat analysis) with rifabutin‐containing regimens (1008 patients) was 73% (67–79%). Respective cure rates for second‐line (223 patients), third‐line (342 patients) and fourth/fifth‐line (95 patients) rifabutin therapies were 79% (67–92%), 66% (55–77%) and 70% (60–79%) respectively. For treating H. pylori infection, almost all studies have administered rifabutin 300 mg/day; this dose seems to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10‐ to 12‐day regimens are generally recommended. The mean rate of adverse effects was 22% (19–25%). Myelotoxicity is the most significant, although this complication was rare. Until now, all patients have recovered of leucopenia uneventfully in a few days, and there have been no reports of infection or other adverse outcomes related to it.

Conclusion  Rifabutin‐containing rescue therapy constitutes an encouraging strategy after multiple (usually three) previous eradication failures with key antibiotics such as amoxicillin, clarithromycin, metronidazole, tetracycline and levofloxacin.
Optimization approach to automatic first arrival picking for three‐component three‐dimensional vertical seismic profiling data
Authors: Blias Emil
Published: December 2011

A new, adaptive multi‐criteria method for accurate estimation of three‐component three‐dimensional vertical seismic profiling of first breaks is proposed. Initially, we manually pick first breaks for the first gather of the three‐dimensional borehole set and adjust several coefficients to approximate the first breaks wave‐shape parameters. We then predict the first breaks for the next source point using the previous one, assuming the same average velocity. We follow this by calculating an objective function for a moving trace window to minimize it with respect to time shift and slope. This function combines four main properties that characterize first breaks on three‐component borehole data: linear polarization, signal/noise ratio, similarity in wave shapes for close shots and their stability in the time interval after the first break. We then adjust the coefficients by combining current and previous values. This approach uses adaptive parameters to follow smooth wave‐shape changes. Finally, we average the first breaks after they are determined in the overlapping windows. The method utilizes three components to calculate the objective function for the direct compressional wave projection. An adaptive multi‐criteria optimization approach with multi three‐component traces makes this method very robust, even for data contaminated with high noise. An example using actual data demonstrates the stability of this method.
Family carer reactions and their related factors among Taiwanese with hospitalized relatives
Authors: Yeh Pi‐Ming , Chang Yuanmay
Published: December 2011

yeh p.‐m. & chang y. (2012) Family carer reactions and their related factors among Taiwanese with hospitalized relatives. Journal of Advanced Nursing68(10), 2195–2206.

Aim.  The purpose of this study was to examine the relationships among family carer reactions and their related factors among Taiwanese with hospitalized relatives.

Background.  In Taiwan, most hospitalized patients have relatives or foreign labourers with them 24 hours a day. Limited research has focused on the reactions of family members who provide care for hospitalized relatives.

Methods.  A cross‐sectional, correlation design was used. A convenience sample of 200 primary carers of hospitalized patients diagnosed with cancer, stroke, and enduring illness was recruited between 2009 and 2010. Data were collected by structured questionnaires.

Results.  The findings indicate that participants with a moderate level of family support experienced a moderate impact on health and finances, but a high impact on schedule. Family carers’ health status and work time were significantly different between, before and after serving as a carer. The multiple regression model variables accounted for 40·1% of the total family carer reaction variance. Three factors were found to predict significantly greater impact on a family carer: (1) lower scores of caregiving knowledge, (2) increasing patient’s activities of daily living dependency and (3) lack of family support.

Conclusion.  It is vital for nurses not only to assess patients’ activities of daily living, but also to assess family carers’ knowledge of caregiving and the patient’s existing family support in developing a plan of care that reduces negative impact on family carers.
Reproductive conflicts in polyandrous and polygynous ant Formica sanguinea
Authors: HAAPANIEMI K. , PAMILO P.
Published: December 2011

The occurrence of multiple reproductives within an ant colony changes the balance between indirect fitness benefits and reproductive competition. We test whether the number of matings by an ant queen (polyandry) correlates negatively with the number of reproductive queens in the colony (polygyny), whether the patrilines and matrilines differ in their contribution to the sexual and worker progeny and whether there is an overall reproductive skew. For these aims, we genotyped both worker and sexual offspring from colonies of the ant Formica sanguinea in three populations. Most colonies were monogynous, but eight (11%) were polygynous with closely related queens. Most queens in the monogynous colonies (86%) had mated with multiple males. The effective paternity was lower than the actual number of mates, and the paternity skew was significant. Furthermore, in some monogynous colonies, the patrilines were differently represented in the worker pupae and sexual pupae produced at the same time. Likewise, the matrilines in polygynous colonies were differently present in worker pupae and male offspring. The effective number of matings by a queen was significantly lower in polygynous colonies (mean me = 1.68) than in monogynous colonies (means 2.06–2.61). The results give support to the hypotheses that polyandry and polygyny are alternative breeding strategies and that reproductive competition can lead to different representation of patrilines and matrilines among the sexual and worker broods.
Functional genomics of trypanosomatids
Authors: CHOI J. , EL‐SAYED N. M.
Published: December 2011

The decoding of the Tritryp reference genomes nearly 7 years ago provided a first peek into the biology of pathogenic trypanosomatids and a blueprint that has paved the way for genome‐wide studies. Although 60–70% of the predicted protein coding genes in Trypanosoma brucei, Trypanosoma cruzi and Leishmania major remain unannotated, the functional genomics landscape is rapidly changing. Facilitated by the advent of next‐generation sequencing technologies, improved structural and functional annotation and genes and their products are emerging. Information is also growing for the interactions between cellular components as transcriptomes, regulatory networks and metabolomes are characterized, ushering in a new era of systems biology. Simultaneously, the launch of comparative sequencing of multiple strains of kinetoplastids will finally lead to the investigation of a vast, yet to be explored, evolutionary and pathogenomic space.