bluuebunny/crossref_metadata_2025 huggingface dataset:
Scattering mechanisms in shallow undoped Si/SiGe quantum wells
Authors: Laroche D. , Huang S.-H. , Nielsen E. , Chuang Y. , Li J.-Y. , Liu C. W. , Lu T. M.
Published: October 2015

We report the magneto-transport study and scattering mechanism analysis of a series of increasingly shallow Si/SiGe quantum wells with depth ranging from ∼ 100 nm to ∼ 10 nm away from the heterostructure surface. The peak mobility increases with depth, suggesting that charge centers near the oxide/semiconductor interface are the dominant scattering source. The power-law exponent of the electron mobility versus density curve, μ ∝ nα, is extracted as a function of the depth of the Si quantum well. At intermediate densities, the power-law dependence is characterized by α ∼ 2.3. At the highest achievable densities in the quantum wells buried at intermediate depth, an exponent α ∼ 5 is observed. We propose and show by simulations that this increase in the mobility dependence on the density can be explained by a non-equilibrium model where trapped electrons smooth out the potential landscape seen by the two-dimensional electron gas.
Domain structures of ferroelectric films under different electrical boundary conditions
Authors: Zhou Z. D. , Wu D. Y.
Published: October 2015

A two-dimensional phase field simulation of ferroelectric films is used that incorporates Landau-Devonshire energy, gradient energy and depolarization electrical energy. A new intermediate electrical boundary condition is firstly presented to study the effects on domain structures of ferroelectric films. Two-dimensional simulations of domain structures are carried out under the open circuit (OC), short circuit (SC) and intermediate (IM) electrical boundary conditions. The simulation results show that there are multi-vortices domains and 180° multi-stripes domains under OC and SC electrical boundary condition, respectively. And there is a transition from multi-vortices domains to 180° multi-stripes domains under the IM electrical boundary condition due to competition between the elastic energy and depolarization electrical energy in the films. The present IM electrical boundary condition can completely characterize different degrees of compensation for surface charges by the electrodes and further describe the effect on the depolarization electrical energy. It can also be reduced to OC and SC electrical boundary conditions. Hence, for nano-thin ferroelectric films, the IM electrical boundary condition plays an important role in the formation of domain structures.
Localized surface plasmon behavior of Ag-Cu alloy nanoparticles stabilized by rice-starch and gelatin
Authors: Singh Manish Kumar , Manda Premkumar , Singh A. K. , Mandal R. K.
Published: October 2015

The purpose of this communication was to understand localized surface plasmon behavior of a series of Ag-Cu alloy nanoparticles capped by rice-starch and gelatin. The structures of dried powders were investigated with the help of X-ray diffraction. The analysis revealed Ag-rich and Cu-rich phases with maximum solid solubility of Cu ∼9 atom per cent; 8 atom per cent and Ag ∼ 16 atom per cent; 14 atom per cent in rice-starch and gelatin capped samples respectively. Transmission electron microscope was used for knowing the particle size as well as to supplement FCC phase formations of Ag-rich and Cu-rich solid phases arrived at based on X-ray diffraction studies. The UV-Vis spectra of sols were examined for the formation and stability of alloy nanoparticles. The temporal evolution of LSPR curves gave us to assert that the sol is stable for more than two months. Small angle X-ray scattering in the sol state was extensively utilized to understand nature of suspensions in terms of fractals. Such a study is important for having a correlation between LSPR behaviors with those of nanoparticle dispersion in aqueous media. It is believed that this work will be a contribution to the emerging field of plasmonics that include applications in the area of photophysical processes and photochemical reactions.
Surface plasmon resonance in nanostructured Ag incorporated ZnS films
Authors: Chalana S. R. , Ganesan V. , Mahadevan Pillai V. P.
Published: October 2015

Silver incorporated zinc sulfide thin films are prepared by RF magnetron sputtering technique and the influence of silver incorporation on the structural, optical and luminescence properties is analyzed using techniques like grazing incidence X-Ray diffraction (GIXRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), micro-Raman spectroscopy, UV-Vis spectroscopy and laser photoluminescence spectroscopy. XRD analysis presents hexagonal wurtzite structure for the films. A reduction of crystallinity of the films is observed due to Ag incorporation. The Raman spectral analysis confirms the reduction of crystallinity and increase of strain due to the Ag incorporation. AFM analysis reveals a rough surface morphology for the undoped film and Ag incorporation makes the films uniform, dense and smooth. A blue shift of band gap energy with increase in Ag incorporation is observed due to quantum confinement effect. An absorption band (450-650 nm region) due to surface plasmon resonance of the Ag clusters present in the ZnS matrix is observed for the samples with higher Ag incorporation. The complex dielectric constant, loss factor and distribution of volume and surface energy loss of the ZnS thin films are calculated. Laser photoluminescence measurements gives an intense bluish green emission from the ZnS films and a quenching of the PL emission is observed which can be due to the metal plasmonic absorption and non-radiative energy transfer due to Ag incorporation.
Correlation between charge transfer and exchange coupling in carbon-based magnetic materials
Authors: Nguyen Anh Tuan , Nguyen Van Thanh , Pham Thi Tuan Anh , Do Viet Thang , Nguyen Huy Sinh , Dam Hieu Chi
Published: October 2015

Several forms of carbon-based magnetic materials, i.e. single radicals, radical dimers, and alternating stacks of radicals and diamagnetic molecules, have been investigated using density-functional theory with dispersion correction and full geometry optimization. Our calculated results demonstrate that the C31H15 (R4) radical has a spin of ½. However, in its [R4]2 dimer structure, the net spin becomes zero due to antiferromagnetic spin-exchange between radicals. To avoid antiferromagnetic spin-exchange of identical face-to-face radicals, eight alternating stacks, R4/D2m/R4 (with m = 3-10), were designed. Our calculated results show that charge transfer (Δn) between R4 radicals and the diamagnetic molecule D2m occurs with a mechanism of spin exchange (J) in stacks. The more electrons that transfer from R4 to D2m, the stronger the ferromagnetic spin-exchange in stacks. In addition, our calculated results show that Δn can be tailored by adjusting the electron affinity (Ea) of D2m. The correlation between Δn, Ea, m, and J is discussed. These results give some hints for the design of new ferromagnetic carbon-based materials.
Formation of the domain structure in CLN under the pyroelectric field induced by pulse infrared laser heating
Authors: Shur V. Ya. , Kosobokov M. S. , Mingaliev E. A. , Karpov V. R.
Published: October 2015

The evolution of the self-assembled quasi-regular micro- and nanodomain structures after pulse infrared laser irradiation in congruent lithium niobate crystal was studied by in situ optical observation. Several scenarios of domain kinetics represented covering of the irradiated zone by nets of the separated domain chains and rays have been revealed. The time dependence of the total domain length was analyzed in terms of modified Kolmogorov-Avrami theory. The domain structure evolution was attributed to the action of pyroelectric field appeared during cooling. The time dependence of the spatial distribution of the pyroelectric field during pulse laser heating and subsequent cooling was calculated by finite element method. The results of computer simulation allowed us to explain the experimental results and can be used for creation of tailored domain structures thus opening the new abilities of the submicron-scale domain engineering in ferroelectrics.
Modeling and analysis for three-dimensional flow with homogeneous-heterogeneous reactions
Authors: Hayat Tasawar , Imtiaz Maria , Almezal Saleh
Published: October 2015

This work addresses the steady three-dimensional boundary layer flow of Maxwell fluid over a bidirectional stretching surface with homogeneous-heterogeneous reactions. A system of ordinary differential equations is obtained by using suitable transformations. Convergent series solutions are derived by homotopic procedure. Impact of various pertinent parameters on the velocity and concentration is discussed. It is noted that an increase in the Deborah number decreases both the velocity components. Also concentration distribution decreases for larger values of strength of homogeneous reaction parameter while it increases for strength of heterogeneous reaction parameter.
Performance change of few layer black phosphorus transistors in ambient
Authors: Ma Xiaomeng , Lu Wanglin , Chen Bingyan , Zhong Donglai , Huang Le , Dong Lijun , Jin Chuanhong , Zhang Zhiyong
Published: October 2015

Transistors were fabricated based on mechanical exfoliated few layer black phosphorus (BP) flakes, and performance change of these devices exposed to air was explored systematically. BP devices were found to suffer severe performance degradation in ambient conditions, and the field effect mobility drops to less than 1/10 of the original in no more than 120 hours after fabrication. However the current on/off ratio shows completely different time dependent behavior to the published result, i.e. increases with exposure time in air, since the minimum current decreases with exposure time to air, which is probably originated from the decrease of layer number in BP. A model is developed to estimate the bandgap change of BP according to the time dependent minimum current of the BP device.
Evaluating the concentration addition approach for describing expected toxicity of a ternary metal mixture (Ni, Cu, Cd) using metal speciation and response surface regression
Authors: Gopalapillai Yamini , Hale Beverley
Published: October 2015

Environmental contextEnvironmental quality guidelines are often based on an ‘additive’ approach using single metal toxicity values. We evaluated the ‘additive’ approach by testing it on three priority pollutant metals (Ni, Cu, Cd), and found that the toxicity of the metal mixture was less than additive when dose was expressed as total metal concentration, but it was additive when dose was expressed as bioavailable metal. We suggest that for metal mixtures, a more realistic indicator of risk is provided by calculations based on the bioavailable form of metals.
AbstractAquatic environments containing elevated metal concentrations, such as natural waters receiving mining effluents, are often a mixture of metals because mineral deposits are commonly an association of multiple metals. Water quality guidelines for protection of aquatic life are not designed for multiple toxicants but are overwhelmingly based on dose–response studies of a single toxicant and assuming additivity. Resolving the uncertainty in risk assessment for metal mixtures in waters surrounding Canada’s many current and legacy extractive mining sites is a high priority for both government and base metal mining companies. Our study evaluated the ‘concentration addition’ approach to predicting the chronic toxicity of a ternary metal mixture (Ni, Cu, Cd) to Lemna minor (a free-floating macrophyte used in biomonitoring of mining effluents) using either total metal concentration as dose or free-ion activity. The aim was to fill several data gaps in mixture toxicity studies, such as: inclusion of water chemistry to calculate metal speciation, test species other than the commonly studied rainbow trout and cladocerans, and test mixture effects on chronic toxicity. Results indicate that toxicity of Ni, Cu plus Cd to L. minor was less than additive (overestimated toxicity) when expressed as total metal concentration but was additive when expressed as free ion (the bioavailable form). We suggest that applying single-element quality guidelines ‘additively’ for plants is likely to overestimate risk to the ecosystem from metal mixtures, and that the use of a concentration addition approach based on the bioavailable form of metals provides a more realistic indicator of risk.
From interpersonal to extended fusion: relationships between fusion with siblings and fusion with the country / Desde la fusión interpersonal a la fusión extendida: Relaciones entre la fusión con los hermanos y la fusión con el país
Authors: Vázquez Alexandra , Gómez Ángel , Ordoñana Juan R. , Paredes Borja
Published: October 2015

Identity fusion is a visceral feeling of oneness with a group. Although research on identity fusion focuses on the alignment of individuals with groups, we propose that fusion can develop between two individuals. In particular, we explore for the first time identity fusion between siblings and its relation with endorsement of extreme behaviour to protect the sibling. In a study conducted with 761 couples of siblings we found that fusion with the sibling is positively associated with willingness to fight and die for the sibling. Additionally, we address the relation between interpersonal and extended fusion. Specifically, a positive association between fusion with the sibling and fusion with the country emerged. The hypothesis that extended fusion might require the projection of interpersonal ties to a large category is discussed.
French Musicology and the Musical Press (1900–14): The Case of La revue musicale, Le mercure musical and La revue musicale SIM
Authors: Duchesneau Michel
Published: October 2015

This article uses the case study of the Revue musicale, founded by Jules Combarieu and Romain Rolland in 1901, to analyse the shape of French musicology at the outset of the twentieth century and, in particular, how social issues surrounding research in the social sciences had an important influence on the orientation of the discipline in subsequent decades. Occupying a position at the heart of French musicological activity in the early years of the century, the project was quickly challenged, leading to the creation of the Mercure musical in 1905, which would eventually become the Revue musicale SIM, published by the Société Internationale de Musique (Section de Paris), in November 1909. After an initial presentation of the journal's editorial project, the article then analyses the founders’ intellectual objectives and explores the links between the journal's structure, its anticipated objectives and the evolution of the discipline through the various publications that followed.
Creating Harmonious Subjects? Ballads, Psalms and Godly Songs for Queen Elizabeth I's Accession Day
Authors: Butler Katherine
Published: October 2015

Queen Elizabeth I (1558–1603) was the first monarch whose Accession Day (17 November) became an occasion for celebration. Poetic tributes to the day frequently evoked images of singing, music-making and dancing, evidence of which can be found in extant single-sheet publications, manuscripts and prayer books, as well as records of now-lost songs in the Stationers’ Register. These songs for Elizabeth's Accession Day reveal how cheaply printed or orally circulated music could become a medium for royal propaganda. Such genres spanned diverse social classes and contexts: from the educated to the illiterate, from street to church; from private household devotions to civic festivities. This countrywide singing was officially encouraged by church and government, as well as fuelled by the local enthusiasm of civic or parish authorities, individual households and commercial printers. It both created an image of England as a harmonious kingdom and attempted to instil such unity in difficult times.
Bridging Divides: Verdi's Requiem in Post-Unification Italy
Authors: Vella Francesca
Published: October 2015

This article addresses the early Italian reception of Verdi's Messa da Requiem (1874), premièred in Milan on the first anniversary of the death of the novelist Alessandro Manzoni. Previous literature has focused on issues of musical genre and the work's political implications (particularly its connections with Manzoni and with late nineteenth-century Italian revivals of ‘old’ sacred music). The article examines, instead, the curiously pluralistic concerns of contemporary critics, as well as certain aspects of Verdi's vocal writing, with the aim of destabilizing traditional dichotomies such as old/new, sacred/operatic, vocal/instrumental and progress/crisis. It argues for more broad-ranging political resonances of Verdi's work, suggesting that the negotiation of a variety of boundaries both in Verdi's music and in its contemporary discussion made the Requiem dovetail with wider cultural attempts to define Italian identity.
Sound of Body: Music, Sports and Health in Victorian Britain
Authors: Sheppard Jennifer R.
Published: October 2015

This article explores ways in which music intersected with the growth of sports in Victorian Britain at the end of the nineteenth century. Although there have been valuable studies of music and sports recently, their main emphasis has been on popular music and contemporary sporting events; a study of the period when playing and watching sports began to acquire its present-day shape has yet to be undertaken. This article moves towards that by examining connections between music and sports through broader social and cultural developments, in particular new ideas about morality, health and physical fitness. It situates commentaries about the healthfulness of music in relation to nineteenth-century discourses about sport, in addition to contextualizing notions of singing and health in the increasing professionalization of Victorian medicine. Finally, this article extends and relocates early twentieth-century encapsulations of singing as physical exercise in the context of concern over degeneration in national fitness.
Reading Uncle Bumba and the Rumba: The Comedian Harmonists and Transnational Youth Culture at the End of the Weimar Republic
Authors: Pennington Stephan
Published: October 2015

This article presents an analytical and cultural reading of the 1932 song ‘Der Onkel Bumba aus Kalumba tanzt nur Rumba’ by the German vocal group the Comedian Harmonists. It incorporates Erving Goffman's stigma theory to propose an alternative interpretation of performances of commercial rumba and jazz by members of a Weimar cosmopolitan youth culture that pushes beyond paradigms of appropriation and exoticism. The author argues that songs seemingly exoticizing an Other could rather serve as a means of articulating concerns of an Othered Self in the context of the rise of National Socialism. The article contrasts a close reading of the Comedian Harmonists’ performance of the song with performances by Leo Monosson and the Melody Gents and incorporates the contrasting experiences of the lyricist Fritz Rotter with those of the Comedian Harmonists to show how ‘Der Onkel Bumba’ presented jazz/rumba as an indicator for both utopian idealism and looming dystopian horror.
Target enhancement and distractor inhibition affect transitory surround suppression in dual tasks using multiple rapid serial visual presentation streams
Authors: Wu Xia , Greenwood Pamela , Fu Shimin
Published: October 2015

Few studies have investigated the interaction between temporal and spatial dimensions on selective attention using dual tasks in the multiple rapid serial visual presentation (RSVP) paradigm. A phenomenon that the surround suppression in space changes over time (termed transitory surround suppression, TSS, in the present study) has been observed, suggesting the existence of this time–space interaction. However, it is still unclear whether target enhancement or distractor inhibition modulates TSS. Four behavioural experiments were conducted to investigate the mechanism of TSS by manipulating the temporal lag and spatial distance factors between two targets embedded in six RSVP streams. The TSS effect was replicated in a study that eliminated confounds of perceptual effects and attentional switch (Experiment 1). However, the TSS disappeared when two targets shared the same colour in a between-subjects design (Experiment 2a) and a within-subject design (Experiment 2b), suggesting the impact of target enhancement on TSS. Moreover, the TSS was larger for within-category than for between-category distractors (Experiment 3), indicating the impact of distractor inhibition on TSS. These two influences on TSS under different processing demands of target and distractor processing were further confirmed in a skeletal design (Experiment 4). Overall, combinative effects of target enhancement and distractor suppression contribute to the mechanisms of time–space interaction in selective attention during visual search.
Induced oligomerization targets Golgi proteins for degradation in lysosomes
Authors: Tewari Ritika , Bachert Collin , Linstedt Adam D.
Published: October 2015

Manganese protects cells against forms of Shiga toxin by down-regulating the cycling Golgi protein GPP130. Down-regulation occurs when Mn binding causes GPP130 to oligomerize and traffic to lysosomes. To determine how GPP130 is redirected to lysosomes, we tested the role of GGA1 and clathrin, which mediate sorting in the canonical Golgi-to-lysosome pathway. GPP130 oligomerization was induced using either Mn or a self-interacting version of the FKBP domain. Inhibition of GGA1 or clathrin specifically blocked GPP130 redistribution, suggesting recognition of the aggregated GPP130 by the GGA1/clathrin-sorting complex. Unexpectedly, however, GPP130’s cytoplasmic domain was not required, and redistribution also occurred after removal of GPP130 sequences needed for its normal cycling. Therefore, to test whether aggregate recognition might be a general phenomenon rather than one involving a specific GPP130 determinant, we induced homo-oligomerization of two unrelated Golgi-targeted constructs using the FKBP strategy. These were targeted to the cis- and trans-Golgi, respectively, using domains from mannosidase-1 and galactosyltransferase. Significantly, upon oligomerization, each redistributed to peripheral punctae and was degraded. This occurred in the absence of detectable UPR activation. These findings suggest the unexpected presence of quality control in the Golgi that recognizes aggregated Golgi proteins and targets them for degradation in lysosomes.
XB130/Tks5 scaffold protein interaction regulates Src-mediated cell proliferation and survival
Authors: Moodley Serisha , Hui Bai Xiao , Kapus Andras , Yang Burton , Liu Mingyao
Published: October 2015

The scaffold protein XB130 regulates cell growth, survival, and migration. Yeast two-hybrid screening suggests that XB130 interacts with another scaffold protein, Tks5. We hypothesized that XB130 and Tks5 form a macromolecular complex to mediate signal transduction cascades for the regulation of cell growth and survival. Coimmunoprecipitation demonstrated that XB130 and Tks5 interact endogenously and form a complex with Src tyrosine kinase. Structure–function studies showed that the fifth SH3 domain of Tks5 binds to the N-terminus of XB130, which contains polyproline-rich motifs. Cell growth and survival studies revealed that down-regulation of XB130 and/or Tks5 reduced cell proliferation, resulting in cell cycle inhibition at the G1 phase and increased caspase 3 activity and apoptosis. Moreover, cell proliferation and survival were increased by overexpression of XB130 or Tks5 but decreased when XB130/Tks5 binding was disrupted by overexpression of XB130 N-terminal deleted mutant and/or Tks5 fifth SH3 domain W1108A mutant. Furthermore, down-regulation of XB130 and/or Tks5 inhibited serum- and growth factor–induced Src activation and downstream phosphorylation of PI3K and Akt. Our results suggest that Tks5, similar to XB130, plays a role in cell proliferation and cell survival and that the interaction between XB130 and Tks5 appears to be critical for regulation of Src-mediated cellular homeostasis.
Cytomegalovirus Genotype Distribution Among Congenitally and Postnatally Infected Patients: Association of Particular Glycoprotein (g)B and gN Types With Symptomatic Disease
Authors: Brañas Patricia , Blázquez-Gamero Daniel , Galindo Alberto , Prieto Columbiana , Olabarrieta Iciar , Cuadrado Irene , Folgueira Lola
Published: October 2015

Background.  Human cytomegalovirus is a leading cause of congenital infection, and there are limited data on prognosis markers in disease development. We aimed to study 3 virology targets (glycoprotein [g]B, gN, and UL144) to assess their correlation with congenital infection and various organ system involvement.

Methods.  Forty-eight congenital cases and 58 postnatally infected children were included (2003–2014). Genotyping for the 3 targets and distribution among the cohorts were investigated, and the relationship between the gB, gN, and UL144 types with clinical manifestations in congenital infection was also studied.

Results.  All of the genotypes were similarly represented among cohorts, and the most prevalent were the UL144B, gB1, and gN1 genotypes. The gB2 genotype was associated with abnormal image findings by ultrasound and/or magnetic resonance in congenital infection (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.1–34.3; P = .036); the gN1 genotype was associated with an elevated risk of developing neurological disorders (OR, 7.0; 95% CI, 1.1–45.9; P = .043). Both gN1 and gB2 were independent factors for symptomatic infection. Statistical analyses showed no association between any UL144 genotype and disease severity.

Conclusions.  All of the genotypes can be involved in congenital infection, although the gB2 and gN1 genotypes might be associated with a more serious illness.
Estimating Onsets of Binary Events in Panel Data
Authors: McGrath Liam F.
Published: October 2015

Onsets of binary events are often of interest to political scientists, whether they be regime changes, the occurrence of civil war, or the signing of bilateral agreements, to name a few. Often researchers transform the binary event outcome of interest, by setting ongoing years to zero, to create a variable which measures the onset of the event. While this may seem an intuitive way to go about estimating models where onset is the outcome of interest, it results in two problems that can affect substantive inferences. First, it creates two qualitatively different meanings for a unit time period to have a zero, which estimators are unable to “know.” Second, it ignores the possibility that variables may have differing effects upon binary event onsets and durations. This article explores how much this transformation can harm our substantive inferences by analytically demonstrating the resulting bias and the use of Monte Carlo experiments, as well as offering recommendations to avoid these problems. I also conduct a sensitivity analysis on the determinants of civil war onset to examine how substantive inferences are affected by this issue. In doing so, I find that there is considerable difference in the size of estimated coefficients and whether a variable is considered a robust determinant of civil war.
The Effect of Clevidipine on Cerebral Blood Flow Velocity and Carbon Dioxide Reactivity in Human Volunteers
Authors: Lemkuil Brian P. , Gierl Brian T. , Patel Piyush M. , Pearn Matthew L. , Nguyen Liem C. , Minokadeh Anushirvan , Drummond John C.
Published: October 2015

Background:

Clevidipine is a short acting, esterase metabolized, calcium channel antagonist administered as a continuous infusion for control of hypertension. Its profile allows for rapid titration and may be uniquely suited to achieving tight hemodynamic targets in neurosurgical and neurocritical care patients. The present study was designed to investigate the effect of clevidipine infusion on cerebral blood flow and cerebral CO2 responsiveness as measured by cerebral blood flow velocity (CBFV) using transcranial Doppler.

Materials and Methods:

CBFV was continuously recorded in 5 healthy subjects during the following conditions: baseline 1 (BL1); baseline with hyperventilation (HV1); baseline 2 (BL2); clevidipine infusion to achieve 15% mean arterial pressure (MAP) reduction (C15); clevidipine infusion to achieve 30% MAP reduction (C30); clevidipine infusion to 30% MAP reduction with hyperventilation (HV2).

Results:

The mean CBFV during intermediate (C15) or maximum (C30) dose clevidipine infusion was unchanged compared with baseline (BL2) (F
2,8=0.66; P=0.54). Cerebral CO2 reactivity, expressed as %∆CBFV/∆mm Hg CO2, was not significantly different in the presence of maximal-dose clevidipine (HV2) as compared with baseline (HV1) (1.6±0.4 vs. 1.6±0.3%∆CBFV/∆mm Hg CO2, P=0.73).

Conclusions:

Clevidipine infusion did not significantly increase CBFV nor was cerebral CO2 reactivity reduced during maximal-dose clevidipine infusion. Further systematic investigation of clevidipine in patients with central nervous system pathology seems justified.
The Potential Prognostic Value of Connexin 43 Expression in Head and Neck Squamous Cell Carcinomas
Authors: Dános Kornél , Brauswetter Diána , Birtalan Ede , Pató Anna , Bencsik Gabriella , Krenács Tibor , Peták István , Tamás László
Published: October 2015

Gap juctions are transmembrane communication channels known to be involved in the control of cell proliferation by mediating the exchange of ions and small molecules between cells. Gap junctions are composed of connexon hemichannels made up of 6 connexin proteins, which abnormal expression and functions have been linked to tumor progression and poorer prognosis. Here, we studied the prognostic impact of the most prevalent connexin isotype, connexin 43 (Cx43) in head and neck squamous cell carcinomas (HNSCC). Tissue microarrays made from tumor samples of 90 HNSCC patients were immunostained for Cx43 and cell cycle regulation–related biomarkers including p53, Ki67, p16ink4, aurora A, geminin, and p21waf1 proteins. Scoring and histopathologic evaluation were performed in digital slides. A 4-tier scoring distinguishing the percentage of positively stained tumor cells was used including score 1: <5%, score 2: 6% to 20%, score 3: 21% to 60%, and score 4: >60%. For statistics, Kaplan-Meier curves with log-rank tests, Cox-regression, and Pearson χ2/Fisher exact tests were used.

A significant positive correlation was found between Cx43 expression and disease-specific survival of patients (P=0.004). The rate of p21waf1 protein–positive tumor cells also proved to be a significant positive prognostic marker (P=0.014). Cx43 levels also showed a significant positive correlation with p53 expression (P=0.036). However, there was no statistical association between Cx43 levels and the rest of the markers tested neither with T, N, or M stage.

In conclusion, our data suggest that reduced Cx43 expression and low p21waf1 protein levels may have a significant negative impact on HNSCC prognosis.
Various Antibody Clones of Napsin A, Thyroid Transcription Factor 1, and p40 and Comparisons With Cytokeratin 5 and p63 in Histopathologic Diagnostics of Non–Small Cell Lung Carcinoma
Authors: Tran Lena , Mattsson Johanna S.M. , Nodin Björn , Jönsson Per , Planck Maria , Jirström Karin , Botling Johan , Micke Patrick , Brunnström Hans
Published: October 2015

Histopathologic classification of cancer in the lung is important for choice of treatment. Cytokeratin 5 (CK5), p63, and p40 are commonly used immunohistochemical markers for squamous cell carcinoma, and napsin A (NAPA) and thyroid transcription factor 1 (TTF-1) are markers for adenocarcinoma of the lung. The aim of the present study was to evaluate these 5 markers and to compare different commercially available antibody clones in lung cancer. Tissue microarrays including 557 cases of surgically treated primary tumors and 73 matched metastases of non–small cell lung carcinoma were stained with CK5, p63, p40 (monoclonal and polyclonal), NAPA (5 different clones/protocols), and TTF-1 (2 different clones). The sensitivity and specificity to separate squamous cell carcinomas from non–small cell carcinomas of nonsquamous type were 95% and 97%, respectively, for CK5, 95% and 87% for p63, 94% and 96% for p40, 75% to 79% and 96% to 98% for the NAPA clones/protocols and 80% to 85% and 95% to 97% for the TTF-1 clones. A combination of NAPA and TTF-1 resulted in a higher sensitivity (85% to 88%), whereas combining CK5 and p40 did not increase the diagnostic performance. The sensitivity was generally lower in evaluation of lung cancer metastases. The κ-values for comparison of staining results between monoclonal and polyclonal p40 and between the 5 NAPA clones/protocols were 0.97 to 1.0, whereas the corresponding figure for the 2 TTF-1 clones was 0.91 to 0.93. Conclusively, CK5 and p40 are good diagnostic markers for squamous cell carcinoma and superior to p63. In addition, it may be useful to combine NAPA and TTF-1 for increased sensitivity in lung cancer diagnostics. There is no substantial difference between monoclonal and polyclonal p40 and between different NAPA clones, whereas there is a difference between the TTF-1 clones 8G7G3/1 and SPT24.
High-Arctic butterflies become smaller with rising temperatures
Authors: Bowden Joseph J. , Eskildsen Anne , Hansen Rikke R. , Olsen Kent , Kurle Carolyn M. , Høye Toke T.
Published: October 2015

The response of body size to increasing temperature constitutes a universal response to climate change that could strongly affect terrestrial ectotherms, but the magnitude and direction of such responses remain unknown in most species. The metabolic cost of increased temperature could reduce body size but long growing seasons could also increase body size as was recently shown in an Arctic spider species. Here, we present the longest known time series on body size variation in two High-Arctic butterfly species:
Boloria chariclea
and
Colias hecla
. We measured wing length of nearly 4500 individuals collected annually between 1996 and 2013 from Zackenberg, Greenland and found that wing length significantly decreased at a similar rate in both species in response to warmer summers. Body size is strongly related to dispersal capacity and fecundity and our results suggest that these Arctic species could face severe challenges in response to ongoing rapid climate change.
Topsy-turvy: turning the counter-current heat exchange of leatherback turtles upside down
Authors: Davenport John , Jones T. Todd , Work Thierry M. , Balazs George H.
Published: October 2015

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.
A phylogenetic community approach for studying termite communities in a West African savannah
Authors: Hausberger Barbara , Korb Judith
Published: October 2015

Termites play fundamental roles in tropical ecosystems, and mound-building species in particular are crucial in enhancing species diversity, from plants to mammals. However, it is still unclear which factors govern the occurrence and assembly of termite communities. A phylogenetic community approach and null models of species assembly were used to examine structuring processes associated with termite community assembly in a pristine savannah. Overall, we did not find evidence for a strong influence of interspecific competition or environmental filtering in structuring these communities. However, the presence of a single species, the mound-building termite
Macrotermes bellicosus
, left a strong signal on structuring and led to clustered communities of more closely related species. Hence, this species changes the assembly rules for a whole community. Our results show the fundamental importance of a single insect species for community processes, suggesting that more attention to insect species is warranted when developing conservation strategies.
Cambrian stem-group annelids and a metameric origin of the annelid head
Authors: Parry Luke , Vinther Jakob , Edgecombe Gregory D.
Published: October 2015

The oldest fossil annelids come from the Early Cambrian Sirius Passet and Guanshan biotas and Middle Cambrian Burgess Shale. While these are among the best preserved polychaete fossils, their relationship to living taxa is contentious, having been interpreted either as members of extant clades or as a grade outside the crown group. New morphological observations from five Cambrian species include the oldest polychaete with head appendages, a new specimen of
Pygocirrus
from Sirius Passet, and an undescribed form from the Burgess Shale. We propose that the palps of
Canadia
are on an anterior segment bearing neuropodia and that the head of
Phragmochaeta
is formed of a segment bearing biramous parapodia and chaetae. The unusual anatomy of these taxa suggests that the head is not differentiated into a prostomium and peristomium, that palps are derived from a modified parapodium and that the annelid head was originally a parapodium-bearing segment.
Canadia
,
Phragmochaeta
and the Marble Canyon annelid share the presence of protective notochaetae, interpreted as a primitive character state subsequently lost in
Pygocirrus
and
Burgessochaeta
, in which the head is clearly differentiated from the trunk.
A Jones matrix formalism for simulating three-dimensional polarized light imaging of brain tissue
Authors: Menzel M. , Michielsen K. , De Raedt H. , Reckfort J. , Amunts K. , Axer M.
Published: October 2015

The neuroimaging technique three-dimensional polarized light imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres—consisting of an axon and a surrounding myelin sheath—are uniaxial birefringent and that the measured optic axis is oriented in the direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve structures smaller than the diameter of single fibres. In the case of fibre bundles, polarimeters with even higher resolutions can be used without losing reliability. When taking the myelin density into account, the derived fibre orientations are considerably improved.
Influence of DNA methylation on positioning and DNA flexibility of nucleosomes with pericentric satellite DNA
Authors: Osakabe Akihisa , Adachi Fumiya , Arimura Yasuhiro , Maehara Kazumitsu , Ohkawa Yasuyuki , Kurumizaka Hitoshi
Published: October 2015

DNA methylation occurs on CpG sites and is important to form pericentric heterochromatin domains. The satellite 2 sequence, containing seven CpG sites, is located in the pericentric region of human chromosome 1 and is highly methylated in normal cells. In contrast, the satellite 2 region is reportedly hypomethylated in cancer cells, suggesting that the methylation status may affect the chromatin structure around the pericentric regions in tumours. In this study, we mapped the nucleosome positioning on the satellite 2 sequence
in vitro
and found that DNA methylation modestly affects the distribution of the nucleosome positioning. The micrococcal nuclease assay revealed that the DNA end flexibility of the nucleosomes changes, depending on the DNA methylation status. However, the structures and thermal stabilities of the nucleosomes are unaffected by DNA methylation. These findings provide new information to understand how DNA methylation functions in regulating pericentric heterochromatin formation and maintenance in normal and malignant cells.
Finite-size corrections in random matrix theory and Odlyzko’s dataset for the Riemann zeros
Authors: Forrester Peter J. , Mays Anthony
Published: October 2015

Odlyzko has computed a dataset listing more than 109successive Riemann zeros, starting from a zero number to beyond 1023. This dataset relates to random matrix theory as, according to the Montgomery–Odlyzko law, the statistical properties of the large Riemann zeros agree with the statistical properties of the eigenvalues of large random Hermitian matrices. Moreover, Keating and Snaith, and then Bogomolny and co-workers, have usedN×Nrandom unitary matrices to analyse deviations from this law. We contribute to this line of study in two ways. First, we point out that a natural process to apply to the dataset is to minimize it by deleting each member independently with some specified probability, and we proceed to compute empirical two-point correlation functions and nearest neighbour spacings in this setting. Second, we show how to characterize the order 1/N2correction term to the spacing distribution for random unitary matrices in terms of a second-order differential equation with coefficients that are Painlevé transcendents, and where the thinning parameter appears only in the boundary condition. This equation can be solved numerically using a power series method. In comparison to the Riemann zero data accurate agreement is exhibited.
Dopamine is a key regulator in the signalling pathway underlying predator-induced defences inDaphnia
Authors: Weiss Linda C. , Leese Florian , Laforsch Christian , Tollrian Ralph
Published: October 2015

The waterfleaDaphniais a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome.Daphniadevelops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation inDaphnia pulexandDaphnia longicephalausing an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity.
An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes
Authors: Giles Sam , Darras Laurent , Clément Gaël , Blieck Alain , Friedman Matt
Published: October 2015

Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) ‘Age of Fishes' remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian,ca373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coevalMimipiscisin displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy inMimipiscisare apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that ofMimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping ofMoythomasiawith Mimiidae.
The evolution of avian wing shape and previously unrecognized trends in covert feathering
Authors: Wang Xia , Clarke Julia A.
Published: October 2015

Avian wing shape has been related to flight performance, migration, foraging behaviour and display. Historically, linear measurements of the feathered aerofoil and skeletal proportions have been used to describe this shape. While the distribution of covert feathers, layered over the anterior wing, has long been assumed to contribute to aerofoil properties, to our knowledge no previous studies of trends in avian wing shape assessed their variation. Here, these trends are explored using a geometric–morphometric approach with landmarks describing the wing outline as well as the extent of dorsal and ventral covert feathers for 105 avian species. We find that most of the observed variation is explained by phylogeny and ecology but shows only a weak relationship with previously described flight style categories, wing loading and an investigated set of aerodynamic variables. Most of the recovered variation is in greater primary covert feather extent, followed by secondary feather length and the shape of the wing tip. Although often considered a plastic character strongly linked to flight style, the estimated ancestral wing morphology is found to be generally conservative among basal parts of most major avian lineages. The radiation of birds is characterized by successive diversification into largely distinct areas of morphospace. However, aquatic taxa show convergence in feathering despite differences in flight style, and songbirds move into a region of morphospace also occupied by basal taxa but at markedly different body sizes. These results have implications for the proposed inference of flight style in extinct taxa.