bluuebunny/crossref_metadata_2025 huggingface dataset:
Bone marrow stromal cells enhance the angiogenesis in ischaemic cortex after stroke: involvement of notch signalling
Authors: Guo Fei , Lv Shigang , Lou Yuanlei , Tu Wei , Liao Wei , Wang Yang , Deng Zhifeng
Published: August 2012

Angiogenesis takes place after brain ischaemia, and stroke‐induced angiogenesis in ischaemic brain may be associated with improved neurological recovery. Bone MSCs (marrow stromal cells) transplantation can promote this vital angiogenesis in ischaemic zones, but the mechanisms by which MSCs promoting angiogenesis are unclear. The Notch signalling pathway may play an important role in embryonic blood vessels development and tumour angiogenesis, but whether it is also involved in angiogenesis after cerebral ischaemia is uncertain. We therefore investigated the Notch signalling pathway in angiogenesis after stroke. Rats were subjected to MCAo (middle cerebral artery occlusion) and treated intravenously with or without MSCs at 24 h after injury. On day 1, 3 and 7 after treatment with MSCs or PBS, immunofluorescent staining, Western blot and RT‐PCR (reverse transcription–PCR) assays were carried out to evaluate angiogenesis, and expression of VEGF (vascular endothelial growth factor) and Notch signals in the ischaemic cortex. Immunofluorescent showed a significant increase in both new microvessels, VEGF‐positive cells and Notch1‐positive microvessels in the ischaemic cortex in MSCs‐treated group. RT‐PCR indicated that MSC transplantation significantly raised VEGF mRNA and Hes1 mRNA levels in the ischaemic cortex. The data suggest that treatment with MSCs enhances stroke‐induced angiogenesis in ischaemic brain, and that the Notch signalling pathway is involved.
The potential and flux landscape theory of evolution
Authors: Zhang Feng , Xu Li , Zhang Kun , Wang Erkang , Wang Jin
Published: August 2012

We established the potential and flux landscape theory for evolution. We found explicitly the conventional Wright's gradient adaptive landscape based on the mean fitness is inadequate to describe the general evolutionary dynamics. We show the intrinsic potential as being Lyapunov function(monotonically decreasing in time) does exist and can define the adaptive landscape for general evolution dynamics for studying global stability. The driving force determining the dynamics can be decomposed into gradient of potential landscape and curl probability flux. Non-zero flux causes detailed balance breaking and measures how far the evolution from equilibrium state. The gradient of intrinsic potential and curl flux are perpendicular to each other in zero fluctuation limit resembling electric and magnetic forces on electrons. We quantified intrinsic energy, entropy and free energy of evolution and constructed non-equilibrium thermodynamics. The intrinsic non-equilibrium free energy is a Lyapunov function. Both intrinsic potential and free energy can be used to quantify the global stability and robustness of evolution. We investigated an example of three allele evolutionary dynamics with frequency dependent selection (detailed balance broken). We uncovered the underlying single, triple, and limit cycle attractor landscapes. We found quantitative criterions for stability through landscape topography. We also quantified evolution pathways and found paths do not follow potential gradient and are irreversible due to non-zero flux. We generalized the original Fisher's fundamental theorem to the general (i.e., frequency dependent selection) regime of evolution by linking the adaptive rate with not only genetic variance related to the potential but also the flux. We show there is an optimum potential where curl flux resulting from biotic interactions of individuals within a species or between species can sustain an endless evolution even if the physical environment is unchanged. We offer a theoretical basis for explaining the corresponding Red Queen hypothesis proposed by Van Valen. Our work provides a theoretical foundation for evolutionary dynamics.
Deuterium–tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF
Authors: Moran M. J. , Bond E. J. , Clancy T. J. , Eckart M. J. , Khater H. Y. , Glebov V. Yu.
Published: August 2012

The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator/photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium–deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Yn) measurements from below 109 (DD) to nearly 1015 (DT). The detectors initially demonstrated detector-to-detector Yn precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of ±10% and precision of ±1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Yn measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10–12 MeV divided by yield 13–15 MeV) with other nTOF detectors.
Microtron MT 25 as a source of neutrons
Authors: Králík M. , Šolc J. , Chvátil D. , Krist P. , Turek K. , Granja C.
Published: August 2012

The objective was to describe Microtron MT25 as a source of neutrons generated by bremsstrahlung induced photonuclear reactions in U and Pb targets. Bremsstrahlung photons were produced by electrons accelerated at energy 21.6 MeV. Spectral fluence of the generated neutrons was calculated with MCNPX code and then experimentally determined at two positions by means of a Bonner spheres spectrometer in which the detector of thermal neutrons was replaced by activation Mn tablets or track detectors CR-39 with a 10B radiator. The measured neutron spectral fluence and the calculated anisotropy served for the estimation of neutron yield from the targets and for the determination of ambient dose equivalent rate at the place of measurement. Microtron MT25 is intended as one of the sources for testing neutron sensitive devices which will be sent into the space.
Probing the spin multiplicity of gas-phase polycyclic aromatic hydrocarbons through their infrared emission spectrum: A theoretical study
Authors: Falvo Cyril , Calvo Florent , Parneix Pascal
Published: August 2012

The anharmonic infrared emission spectrum following an optical excitation has been calculated for a variety of polycyclic aromatic hydrocarbon molecules in their ground singlet electronic state or in their triplet state. The computational protocol relies on second-order perturbation theory and involves a quartic vibrational Hamiltonian, the vibrational quantum numbers being sampled according to a Monte Carlo procedure. In the case of neutral naphthalene, the IR spectrum obtained in the (ground) singlet state differs significantly from the spectrum in the triplet state, especially for out-of-plane CH bending modes. Although not as prominent, spectral differences in larger molecules are still observable.
A soft and transparent handleable protein model
Authors: Kawakami Masaru
Published: August 2012

The field of structural biology currently relies on computer-generated graphical representations of three-dimensional (3D) structures to conceptualize biomolecules. As the size and complexity of the molecular structure increases, model generation and peer discussions become more difficult. It is even more problematic when discussing protein–protein interactions wherein large surface area contact is considered. This report demonstrates the viability of a new handleable protein molecular model with a soft and transparent silicone body similar to the molecule's surface. A full-color printed main chain structure embedded in the silicone body enables users to simultaneously feel the molecular surface, view through the main chain structure, and manually simulate molecular docking. The interactive, hands-on experience deepens the user's intuitive understanding of the complicated 3D protein structure and elucidates ligand binding and protein–protein interactions. This model would be an effective discussion tool for the classroom or laboratory that stimulates inspired learning in this study field.
Multi-parametric R-matrix for the $\mathfrak {sl}(2|1)$sl(2|1) Yangian
Authors: Babichenko Andrei , Torrielli Alessandro
Published: August 2012

We study the Yangian of the \documentclass[12pt]{minimal}\begin{document}$\mathfrak {sl}(2|1)$\end{document}sl(2|1) Lie superalgebra in a multi-parametric four-dimensional representation. We use Drinfeld's second realization to independently rederive the R-matrix, and to obtain the antiparticle representation, the crossing and the unitarity condition. We consistently apply the Yangian antipode and its inverse to the individual particles involved in the scattering. We explicitly find a scalar factor solving the crossing and unitarity conditions, and study the analytic structure of the resulting dressed R-matrix. The formulas we obtain bear some similarities with those familiar from the study of integrable structures in the Anti de Sitter (AdS) / Conformal Field Theory (CFT) correspondence, although they present obvious crucial differences.
Spin-orbit coupled potential energy surfaces and properties using effective relativistic coupling by asymptotic representation
Authors: Ndome Hameth , Eisfeld Wolfgang
Published: August 2012

A new method has been reported recently [H. Ndome, R. Welsch, and W. Eisfeld, J. Chem. Phys. 136, 034103 (2012)]10.1063/1.3675846 that allows the efficient generation of fully coupled potential energy surfaces (PESs) including derivative and spin-orbit (SO) coupling. The method is based on the diabatic asymptotic representation of the molecular fine structure states and an effective relativistic coupling operator and therefore is called effective relativistic coupling by asymptotic representation (ERCAR). The resulting diabatic spin-orbit coupling matrix is constant and the geometry dependence of the coupling between the eigenstates is accounted for by the diabatization. This approach allows to generate an analytical model for the fully coupled PESs without performing any ab initio SO calculations (except perhaps for the atoms) and thus is very efficient. In the present work, we study the performance of this new method for the example of hydrogen iodide as a well-established test case. Details of the diabatization and the accuracy of the results are investigated in comparison to reference ab initio calculations. The energies of the adiabatic fine structure states are reproduced in excellent agreement with reference ab initio data. It is shown that the accuracy of the ERCAR approach mainly depends on the quality of the underlying ab initio data. This is also the case for dissociation and vibrational level energies, which are influenced by the SO coupling. A method is presented how one-electron operators and the corresponding properties can be evaluated in the framework of the ERCAR approach. This allows the computation of dipole and transition moments of the fine structure states in good agreement with ab initio data. The new method is shown to be very promising for the construction of fully coupled PESs for more complex polyatomic systems to be used in quantum dynamics studies.
Synchrotron FTIR spectroscopy of weak torsional bands: A case study of cis-methyl formate
Authors: Tudorie M. , Ilyushin V. , Auwera J. Vander , Pirali O. , Roy P. , Huet T. R.
Published: August 2012

The far infrared spectrum of cis-methyl formate has been recorded on the AILES beamline of the synchrotron SOLEIL using a Fourier transform infrared spectrometer coupled to a long path cell. The very weak fundamental band associated with the methyl-top torsion mode (ν18) was observed. The frequency analysis was performed using the “rho axis method”, and the microwave and millimeter-wave data from the literature. A precise determination of the band origins (${\rm \nu }_{18}^A$ν18A = 132.4303 cm−1 and ${\rm \nu }_{18}^E$ν18E = 131.8445 cm−1) and of the barrier height [V3 = 370.7398 (58) cm−1] have been obtained. The intensity of the ν18 fundamental band was determined to be 3.4 × 10−21 cm−1/(molecule cm−2) at 297 K, equally shared among A–A and E–E transitions, thus leading to a dipole moment component μc(3) equal to 0.0483 D. The results were compared with the ab initio calcula-tions of Senent et al. [Astrophys. J. 627, 567 (2005)]10.1086/430201.
Development of a compact and long range XYθz nano-positioning stage
Authors: Kim Hyunchang , Gweon Dae-Gab
Published: August 2012

In this study, we describe the development of a novel, compact, and long range in-plane XYθz nano-positioning stage with piezoelectric actuator and flexure mechanism. The stage is composed of an X-directional motion part and a Y, θz-directional motion part, which are linked serially. The stage consists of a bridge-type amplifying mechanism for the amplification of deformation of the piezoelectric actuator, a double compound guide mechanism for performing only desired motion, and a circular hinge mechanism that permits rotational motion in the Y and θz-stages. To set the design variables of the stage, optimal design is carried out. To verify the results of the optimal design process and the performance of the stage, the FEM simulation and experiment are carried out. The proposed XYθz nano-positioning stage has a translational motion range of 700 μm and a rotational motion range of 0.3°; it has a closed-loop resolution of 5 nm, 5 nm, and 0.025 arcsec in the X-, Y-, and θz-directional motions, respectively. The proposed stage is a novelty in that it has a compact size of 200 × 200 × 30 mm3, and decoupled kinematic design.
Sensitivity of the thermal and acoustic virial coefficients of argon to the argon interaction potential
Authors: Wiebke Jonas , Pahl Elke , Schwerdtfeger Peter
Published: August 2012

Second, third, and fourth thermal and acoustic virial coefficients between 100 and 1000 K are computed for different argon interaction models derived from combinations of accurate two- and three-body potentials. Differences between the various interaction models tested mirror the presumed order in the accuracy of these models, but are not well captured at the level of the lowest-order contributions in the virial expansion: While the second- and third-order virial coefficients are found to be rather insensitive to small variations in the two- and three-body potentials, more pronounced differences in higher-order coefficients are currently of limited use in assessing the accuracy of the interaction potential due to difficulties in the unambiguous experimental determination of these higher-order coefficients. In contrast, pressure–volume and speed-of-sound data – both of which are experimentally known to highest accuracies – are found to be insensitive to small variations in the interaction model. All but the least accurate models reproduce experimental pressure–volume and speed-of-sound data near-quantitatively in regions where the (fourth-order) virial expansions apply. All quantities considered are found to be completely unaffected by a non-vanishing quadruple-dipole four-body potential.
Ab initio MRSDCI study on the low-lying electronic states of the lithium chloride molecule (LiCl)
Authors: Kurosaki Yuzuru , Yokoyama Keiichi
Published: August 2012

Potential energy curves (PECs) for the low-lying states of the lithium chloride molecule (LiCl) have been calculated using the internally contracted multireference single- and double-excitation configuration interaction (MRSDCI) method with the aug-cc-PVnZ (AVnZ) and aug-cc-PCVnZ (ACVnZ) basis sets, where n = T, Q, and 5. First, we calculate PECs for 7 spin-orbit (SO)-free Λ-S states, X1Σ+, A1Σ+, 3Σ+, 1Π, and 3Π, and then obtain PECs for 13 SO Ω states, X0+, A0+, B0+, 0−(I), 0−(II), 1(I), 1(II), 1(III), and 2, by diagonalizing the matrix of the electronic Hamiltonian plus the Breit-Pauli SO Hamiltonian. The MRSDCI calculations not including core orbital correlation through the single and double excitations are also performed with the AV5Z and ACV5Z basis sets. The Davidson corrections (Q0) are added to both the Λ-S and Ω state energies. Vibrational eigenstates for the obtained X1Σ+ and X0+ PECs are calculated by solving the time-independent Schrödinger equation with the grid method. Thus, the effects of basis set, core orbital correlation, and the Davidson correction on the X1Σ+ and X0+ PECs of LiCl are investigated by comparing the spectroscopic constants calculated from the PECs with one another and with experiment. It is confirmed that to accurately predict the spectroscopic constants we need to include core-electron correlation in the CI expansion and use the basis sets designed to describe core-valence correlation, i.e., ACVnZ. The SO PECs presented in this paper will be of help in the future study of diatomic alkali halide dynamics.
Structure-based coarse-graining in liquid slabs
Authors: Jochum Mara , Andrienko Denis , Kremer Kurt , Peter Christine
Published: August 2012

Structure-based coarse-graining relies on matching the pair correlation functions of a reference (atomistic) and a coarse-grained system. As such, it is designed for systems with uniform density distributions. Here, we demonstrate how it can be generalized for inhomogeneous systems by coarse-graining slabs of liquid water and methanol in vacuum, as well as a single benzene molecule at the water-vacuum interface. Our conclusion is that coarse-graining performed in inhomogeneous systems improves thermodynamic properties and the structure of interfaces without significant alterations to the local structure of the bulk liquid.
Measurements of parallel electron velocity distributions using whistler wave absorption
Authors: Thuecks D. J. , Skiff F. , Kletzing C. A.
Published: August 2012

We describe a diagnostic to measure the parallel electron velocity distribution in a magnetized plasma that is overdense (ωpe > ωce). This technique utilizes resonant absorption of whistler waves by electrons with velocities parallel to a background magnetic field. The whistler waves were launched and received by a pair of dipole antennas immersed in a cylindrical discharge plasma at two positions along an axial background magnetic field. The whistler wave frequency was swept from somewhat below and up to the electron cyclotron frequency ωce. As the frequency was swept, the wave was resonantly absorbed by the part of the electron phase space density which was Doppler shifted into resonance according to the relation ω − k‖v‖ = ωce. The measured absorption is directly related to the reduced parallel electron distribution function integrated along the wave trajectory. The background theory and initial results from this diagnostic are presented here. Though this diagnostic is best suited to detect tail populations of the parallel electron distribution function, these first results show that this diagnostic is also rather successful in measuring the bulk plasma density and temperature both during the plasma discharge and into the afterglow.
Probing individual weakly-coupled π-conjugated molecules on semiconductor surfaces
Authors: Münnich G. , Albrecht F. , Nacci C. , Utz M. , Schuh D. , Kanisawa K. , Fölsch S. , Repp J.
Published: August 2012

A weak perturbation of a single molecule by the supporting substrate is a key ingredient to molecular electronics. Here, we show that individual phthalocyanine molecules adsorbed on GaAs(110) and InAs(111)A surfaces represent prototypes for weakly coupled single-molecule/semiconductor hybrid systems. This is demonstrated by scanning tunneling spectroscopy and bias-dependent images that closely resemble orbital densities of the free molecule. This is in analogy to results for molecules decoupled from a metal substrate by an ultrathin insulating layer and proves a weak electronic molecule-substrate coupling. Therefore, such systems will allow single-molecule functionality to be combined with the versatility of semiconductor physics.
A stochastic mechanism of electron heating
Authors: Galinsky V. L. , Shevchenko V. I.
Published: August 2012

Due to Landau resonant interaction with lower hybrid waves in the lower hybrid current drive scheme part of electrons are accelerated and, as a result of this, a tail of energetic electrons is formed on the electron distribution function. The same situation takes place in the problem of type III radio bursts when the suprathermal burst electrons acquire a plateau distribution due to excitation of plasma waves in the solar wind plasma. These distributions are unstable with respect to the cyclotron excitation of waves at anomalous Doppler resonance (“fan” instability). In this case, the tail electrons interact simultaneously with both (i) waves that accelerate or decelerate them (Čerenkov resonance) and (ii) waves excited in the process of the fan instability that led to their pitch angle diffusion. Because velocity diffusion lines of electrons formed due to heir interaction with each type of waves intersect, this interaction can lead not only to pitch angle diffusion but also to heating of electrons mainly in perpendicular direction. We investigated this mechanism of electron heating and studied the temporal evolution of the electron temperature and the energy of excited waves. Our results show significant enhancement of the electron perpendicular temperature T⊥ due to this stochastic heating mechanism.
Deformation induced martensite in NiTi and its shape memory effects generated by low temperature laser shock peening
Authors: Liao Yiliang , Ye Chang , Lin Dong , Suslov Sergey , Cheng Gary J.
Published: August 2012

In this study, laser shock peening (LSP) was utilized to generate localized deformation induced martensite (DIM) in NiTi shape memory alloy. The DIM was investigated by x-ray diffraction and transmission electron microscopy. The effects of temperature and laser intensity on DIM transformation were investigated. It has been found that higher laser intensity and lower processing temperature leads to higher volume fraction of DIM. This is attributed to the increase of the chemical driving force and the increase in the density of potential martensite variant for martensite nucleation at low temperatures. The localized shape memory effect in micrometer scale after low temperature LSP has been evaluated.
Selective growth of ZnO nanorods and their applications to ferroelectric nanorods
Authors: Fujisawa Hironori , Imi Yasunori , Nakashima Seiji , Shimizu Masaru , Kotaka Yasutoshi , Honda Koichiro
Published: August 2012

We describe the selective growth of ZnO nanorods by metalorganic chemical vapor deposition using Pt layers patterned on SiO2/Si by photolithography as nucleation sites, as well as their application to ferroelectric nanorods. The growth of ZnO nanorods on the SiO2 and Pt surfaces was quite different in the nucleation stage. Under specific growth conditions, no nucleation was observed on the SiO2 surface due to its stable and less reactive nature while nucleation easily occurred on Pt due to its catalytic properties. Using this difference, we achieved selective growth of c-axis oriented ZnO nanorods only on Pt dots with lateral dimensions of 40 μm × 40 μm and diameter of 300 nm on the SiO2/Si substrate. The average diameter and length of selectively grown ZnO nanorods were 70–80 nm and ∼10 μm, respectively. By depositing 100-nm-thick Pb(Zr,Ti)O3 layers on the selectively grown ZnO nanorods, Pb(Zr,Ti)O3-covered ZnO nanorods were successfully grown selectively on the patterned Pt layers. These results demonstrate the feasibility of position control of nanorod growth by self-assembly in combination with photolithography for future ferroelectric device applications.
Closed-loop control of laser assisted chemical vapor deposition growth of carbon nanotubes
Authors: van de Burgt Yoeri , Bellouard Yves , Mandamparambil Rajesh , Haluska Miro , Dietzel Andreas
Published: August 2012

Laser-assisted chemical vapor deposition growth is an attractive mask-less process for growing locally aligned nanotubes in selected places on temperature sensitive substrates. An essential parameter for a successful and reproducible synthesis of nanotubes is the temperature during growth. Here, we demonstrate a temperature feedback control mechanism based on the dynamic, in situ monitoring of the infrared radiation coupled with reflectivity information. With the information provided by these sensors, an infrared laser, focused on a silicon substrate covered with aluminum-oxide and iron catalyst layers, can be controlled. The growth takes place in a gaseous mixture of argon (carrier gas), hydrogen (process gas), and ethylene (carbon-containing gas). Scanning electron microscopy and Raman spectroscopy analysis demonstrate the excellent reproducibility of the closed-loop control process over multiple experiments. Furthermore, we developed a unique method to identify the onset for catalyst formation and activation by monitoring the fluctuation of the reflected laser beam.
Do desert dingoes drink daily? Visitation rates at remote waterpoints in the Strzelecki Desert
Authors: Allen Benjamin L.
Published: August 2012

Dingoes (Canis lupus dingo) are water-limited apex predators in Australian terrestrial systems, but observations of dingoes in arid areas far removed from water suggest that dingoes may not always need access to free water to persist. Data from GPS-collared dingoes in the Strzelecki Desert were used to measure waterpoint visitation rates of eight dingoes from four adjacent territories. Each dingo regularly went 3–5 days without visiting waterpoints in all seasons, and individuals of the same pack visited waterpoints at different frequencies and at different times of the day. The longest period without visiting a waterpoint was 22 days in summer and winter from two different individuals. These results have implications for places where dingo baiting occurs, and suggest that diet may play an important role in the use of waterpoints by dingoes.
Effect of dietary fish oil on n-3 fatty acid content of meat from broiler chickens fed low protein diets
Authors: Navidshad Bahman , Boo Liang Juan , Akhlaghi Amir
Published: August 2012

An experiment was carried out to evaluate the effects of dietary fish oil and crude protein (CP) levels on fatty acid composition of the thigh and breast tissues of broiler chickens. Four hundred and fifty, 1-day-old mixed-sex broiler chicks were used in a completely randomised design with factorial arrangement consisting of two dietary CP levels (21 v. 18.0% and 19 v. 17.1% for grower and finisher diets, respectively), and three levels of fish oil inclusion (0, 2 or 4%). Specific increases in eicosapentaenoic acid (EPA, 20 : 5) and docosahexaenoic acid (DHA, 22 : 6) were observed in breast and thigh tissues as a response to increased fish oil supplementation. The n-6 : n-3 fatty acid ratio in breast and thigh meat samples decreased (P < 0.05) in birds fed low protein diets, but dietary protein level led to no alteration in the total n-3 fatty acids of the tissues (P > 0.05). Thigh tissue of chickens fed low protein diets had a higher concentration of DHA (P < 0.05), while the DHA and EPA concentrations in breast tissue were not affected by dietary protein level (P > 0.05). Results of the present study showed that fish oil can be used to fortify EPA and DHA levels in chicken meat and there is an interaction between dietary fatty acids and protein level on meat oxidative stability, and a reduction in dietary protein level may lead to a better oxidative stability of chicken meat.
Steam-pelleting and feed form of broiler diets based on three coarsely ground sorghums influences growth performance,nutrient utilisation, starch and nitrogen digestibility
Authors: Selle P. H. , Liu S. Y. , Cai J. , Cowieson A. J.
Published: August 2012

Sorghum grains with red, white and yellow seed colours were coarsely ground and incorporated into nutritionally equivalent diets that were offered to broiler chicks in three feed forms. The diets were fed as mash or steam-pelleted at a conditioning temperature of 90°C and fed as intact pellets or ground back into mash as reground pellets. The effects of a 3 × 3 factorial array of dietary treatments offered to male chicks from 6 to 27 days post-hatch on growth performance, nutrient utilisation and apparent digestibility coefficients of starch and nitrogen (N) at the proximal jejunum, proximal ileum and distal ileum were determined. Feed form had a greater impact on the parameters assessed than did sorghum seed colour, but several interactions between these main effects were observed. Steam-pelleting diets reduced protein solubility and this was correlated with increased concentrations of disulfide bonds and decreased concentrations of free sulphydryl groups. Steam-pelleting diets significantly depressed N retention in broiler chicks and this reduction was appropriately correlated with concentrations of disulfide bonds and free sulphydryl groups and dietary protein solubility. While N retention was depressed, in a curious outcome, steam-pelleting diets did not compromise N digestibility along the small intestine. Steam-pelleting diets significantly increased starch digestibility coefficients in the proximal jejunum, with differing responses among the sorghums, but not in the two ileal levels. Phytate concentrations in the three sorghums were negatively correlated with N digestibility coefficients at the proximal jejunum and proximal ileum. The implications of the present feeding study in relation to the performance of broiler chickens offered steam-pelleted, sorghum-based diets are discussed.
Direct sampling of cystic fibrosis lungs indicates that DNA-based analyses of upper-airway specimens can misrepresent lung microbiota
Authors: Goddard Amanda F. , Staudinger Benjamin J. , Dowd Scot E. , Joshi-Datar Amruta , Wolcott Randall D. , Aitken Moira L. , Fligner Corinne L. , Singh Pradeep K.
Published: August 2012

Recent work using culture-independent methods suggests that the lungs of cystic fibrosis (CF) patients harbor a vast array of bacteria not conventionally implicated in CF lung disease. However, sampling lung secretions in living subjects requires that expectorated specimens or collection devices pass through the oropharynx. Thus, contamination could confound results. Here, we compared culture-independent analyses of throat and sputum specimens to samples directly obtained from the lungs at the time of transplantation. We found that CF lungs with advanced disease contained relatively homogenous populations of typical CF pathogens. In contrast, upper-airway specimens from the same subjects contained higher levels of microbial diversity and organisms not typically considered CF pathogens. Furthermore, sputum exhibited day-to-day variation in the abundance of nontypical organisms, even in the absence of clinical changes. These findings suggest that oropharyngeal contamination could limit the accuracy of DNA-based measurements on upper-airway specimens. This work highlights the importance of sampling procedures for microbiome studies and suggests that methods that account for contamination are needed when DNA-based methods are used on clinical specimens.
Task-switching costs promote the evolution of division of labor and shifts in individuality
Authors: Goldsby Heather J. , Dornhaus Anna , Kerr Benjamin , Ofria Charles
Published: August 2012

From microbes to humans, the success of many organisms is achieved by dividing tasks among specialized group members. The evolution of such division of labor strategies is an important aspect of the major transitions in evolution. As such, identifying specific evolutionary pressures that give rise to group-level division of labor has become a topic of major interest among biologists. To overcome the challenges associated with studying this topic in natural systems, we use actively evolving populations of digital organisms, which provide a unique perspective on the de novo evolution of division of labor in an open-ended system. We provide experimental results that address a fundamental question regarding these selective pressures: Does the ability to improve group efficiency through the reduction of task-switching costs promote the evolution of division of labor? Our results demonstrate that as task-switching costs rise, groups increasingly evolve division of labor strategies. We analyze the mechanisms by which organisms coordinate their roles and discover strategies with striking biological parallels, including communication, spatial patterning, and task-partitioning behaviors. In many cases, under high task-switching costs, individuals cease to be able to perform tasks in isolation, instead requiring the context of other group members. The simultaneous loss of functionality at a lower level and emergence of new functionality at a higher level indicates that task-switching costs may drive both the evolution of division of labor and also the loss of lower-level autonomy, which are both key components of major transitions in evolution.
Sacrificial nanofibrous composites provide instruction without impediment and enable functional tissue formation
Authors: Baker Brendon M. , Shah Roshan P. , Silverstein Amy M. , Esterhai John L. , Burdick Jason A. , Mauck Robert L.
Published: August 2012

The fibrous tissues prevalent throughout the body possess an ordered structure that underlies their refined and robust mechanical properties. Engineered replacements will require recapitulation of this exquisite architecture in three dimensions. Aligned nanofibrous scaffolds can dictate cell and matrix organization; however, their widespread application has been hindered by poor cell infiltration due to the tight packing of fibers during fabrication. Here, we develop and validate an enabling technology in which tunable composite nanofibrous scaffolds are produced to provide instruction without impediment. Composites were formed containing two distinct fiber fractions: slow-degrading poly(ε-caprolactone) and water-soluble, sacrificial poly(ethylene oxide), which can be selectively removed to increase pore size. Increasing the initial fraction of sacrificial poly(ethylene oxide) fibers enhanced cell infiltration and improved matrix distribution. Despite the removal of >50% of the initial fibers, the remaining scaffold provided sufficient instruction to align cells and direct the formation of a highly organized ECM across multiple length scales, which in turn led to pronounced increases in the tensile properties of the engineered constructs (nearly matching native tissue). This approach transforms what is an interesting surface phenomenon (cells on top of nanofibrous mats) into a method by which functional, 3D tissues (>1 mm thick) can be formed, both in vitro and in vivo. As such, this work represents a marked advance in the engineering of load-bearing fibrous tissues, and will find widespread applications in regenerative medicine.
An aggression-specific cell type in the anterior hypothalamus of finches
Authors: Goodson James L. , Kelly Aubrey M. , Kingsbury Marcy A. , Thompson Richmond R.
Published: August 2012

The anterior hypothalamus (AH) is a major integrator of neural processes related to aggression and defense, but cell types in the AH that selectively promote aggression are unknown. We here show that aggression is promoted in a very selective and potent manner by dorsal AH neurons that produce vasoactive intestinal polypeptide (VIP). Fos activity in a territorial finch, the violet-eared waxbill (Estrildidae:Uraeginthus granatina) is positively related to aggression in the dorsal AH, overlapping a population of VIP-producing neurons. VIP is known to promote territorial aggression in songbirds, and thus we used antisense oligonucleotides to selectively block AH VIP production in male and female waxbills. This manipulation virtually abolishes aggression, reducing the median number of displacements in a 3-min resident–intruder test from 38 in control subjects to 0 in antisense subjects. Notably, most antisense and control waxbills exhibit an agonistic response such as a threat or agonistic call within 2 s of intrusion. Thus, antisense subjects clearly classify intruders as offensive, but fail to attack. Other social and anxiety-like behaviors are not affected and VIP cell numbers correlate positively with aggression, suggesting that these cells selectively titrate aggression. Additional experiments in the gregarious zebra finch (Estrildidae:Taeniopygia guttata) underscore this functional specificity. Colony-housed finches exhibit significant reductions in aggression (primarily nest defense) following AH VIP knockdown, but no effects are observed for social preferences, pair bonding, courtship, maintenance behaviors, or anxiety-like behaviors. To our knowledge, these findings represent a unique identification of an aggression-specific cell type in the brain.
Essential anaplerotic role for the energy-converting hydrogenase Eha in hydrogenotrophic methanogenesis
Authors: Lie Thomas J. , Costa Kyle C. , Lupa Boguslaw , Korpole Suresh , Whitman William B. , Leigh John A.
Published: August 2012

Despite decades of study, electron flow and energy conservation in methanogenic Archaea are still not thoroughly understood. For methanogens without cytochromes, flavin-based electron bifurcation has been proposed as an essential energy-conserving mechanism that couples exergonic and endergonic reactions of methanogenesis. However, an alternative hypothesis posits that the energy-converting hydrogenase Eha provides a chemiosmosis-driven electron input to the endergonic reaction. In vivo evidence for both hypotheses is incomplete. By genetically eliminating all nonessential pathways of H
2
metabolism in the model methanogen
Methanococcus maripaludis
and using formate as an additional electron donor, we isolate electron flow for methanogenesis from flux through Eha. We find that Eha does not function stoichiometrically for methanogenesis, implying that electron bifurcation must operate in vivo. We show that Eha is nevertheless essential, and a substoichiometric requirement for H
2
suggests that its role is anaplerotic. Indeed, H
2
via Eha stimulates methanogenesis from formate when intermediates are not otherwise replenished. These results fit the model for electron bifurcation, which renders the methanogenic pathway cyclic, and as such requires the replenishment of intermediates. Defining a role for Eha and verifying electron bifurcation provide a complete model of methanogenesis where all necessary electron inputs are accounted for.
Prolonged persistence of measles virus RNA is characteristic of primary infection dynamics
Authors: Lin Wen-Hsuan W. , Kouyos Roger D. , Adams Robert J. , Grenfell Bryan T. , Griffin Diane E.
Published: August 2012

Measles virus (MeV) is the poster child for acute infection followed by lifelong immunity. However, recent work shows the presence of MeV RNA in multiple sites for up to 3 mo after infection in a proportion of infected children. Here, we use experimental infection of rhesus macaques to show that prolonged RNA presence is characteristic of primary infection. We found that viral RNA persisted in the blood, respiratory tract, or lymph nodes four to five times longer than the infectious virus and that the clearance of MeV RNA from blood happened in three phases: rapid decline coincident with clearance of infectious virus, a rebound phase with increases up to 10-fold, and a phase of slow decrease to undetectable levels. To examine the effect of individual host immune factors on MeV load dynamics further, we developed a mathematical model that expressed viral replication and elimination in terms of the strength of MeV-specific T-cell responses, antibody responses, target cell limitations, and immunosuppressive activity of regulatory T cells. Based on the model, we demonstrate that viral dynamics, although initially regulated by T cells, require antibody to eliminate viral RNA. These results have profound consequences for our view of acute viral infections, the development of prolonged immunity, and, potentially, viral evolution.
Muhammad Ghaffari: The Persian Painter of Modern Life
Authors: Diba Layla S.
Published: August 2012

In the late nineteenth century, Qajar Iran, like its neighbor the Ottoman Empire, faced the dual challenges of colonialism and modernity. This paper considers the role of art education and art production in its response to these forces, focusing on the leading court painter of the late Qajar period, Mirza Muhammad Ghaffari, Kamal al-Mulk (1848–1941), whose career bridged the late Qajar period and the early twentieth century. Early in his career, Ghaffari was recognized as the leading exponent of academic painting, yet by the constitutional period his art had evolved into a style representing contemporary Persian life, a style which was informed by nationalistic discourses current in intellectual and political circles. This paper's consideration of the evolution of his style from a European modernism to an authentic Iranian modernism includes Ghaffari's training as a painter, the role of photography in the development of his style, his travel to Europe, and parallels with the art and career of the Ottoman painter Osman Hamdi.
Dosimetric features and kinetic analysis of thermoluminescence from ultra-high molecular weight polyethylene
Authors: Chithambo M L
Published: August 2012

Thermoluminescence (TL) from beta irradiated ultra-high molecular weight polyethylene has been studied for measurements between 30 and 200 °C. An aliquot studied in this work produced TL glow curves consisting of two peaks, the main peak at 88 °C and a weaker intensity peak at 148 °C for heating at 1 °C s−1 following an excitation dose of 215 Gy. The position of the main peak is poorly reproducible for heating rates of 0.2 and 0.6 °C s−1 investigated with the peak position decreasing when the sample is freshly irradiated and the TL re-measured. The said change in peak position is however less of an effect for measurements made at 1 °C s−1 with the peak position being fairly reproducible in this case. Further measurements of the dosimetric properties of ultra-high molecular weight polyethylene showed that its dose response is linear from 26 Gy to about 161 Gy but exhibits slower growth in intensity with dose from about 860 Gy after regions of sub- and supra-linearity in between. If the TL is not measured immediately after irradiation, the signal fades with the delay approximately exponentially. In addition, a number of tests including phosphorescence analysis showed the possibility that the order of kinetics might not be unique but sensitive to several factors including measurement temperature. Thus for instance, the dependence of the peak position on the stop temperature in the partial heating procedure T
m − T
stop implied first-order kinetics but analysis of the geometrical factor μ
g for the same set of data gave μ
g = 0.46 ± 0.03 a value corresponding to characteristics somewhat intermediate between first and second order. In comparison, the results of analysis of the phosphorescence recorded at several temperatures on the rising edge of the main peak were only in agreement for measurements at 40 °C with general-order analysis suggesting second-order kinetics apply as did TL-like transformation of the monotonic phosphorescence decay. Both results were also consistent with an additional finding that the time dependence of the isothermal decay at 40 °C was consistent with second-order kinetics. Analysis of the TL for the activation energy using the initial rise method, variable heating rate procedure, TL-like transformation of phosphorescence and the peak shape estimates, produced a self-consistent set of values equal to 0.76 ±0.05 eV, 0.66±0.03 eV, 0.77±0.06 eV and values of the order of 0.8 eV, respectively. The kinetic parameters found in this study compare favourably with literature values.
Influence of hydrogen addition to an Ar plasma on the structural properties of TiO2−x thin films deposited by RF sputtering
Authors: Luciu I , Bartali R , Laidani N
Published: August 2012

The influence of hydrogen addition to an Ar plasma on the structural properties of TiO2−x
films produced by RF sputtering of a TiO2 target at room temperature was studied. The structural properties of the films were characterized by x-ray photoelectron spectroscopy while the surface morphology was analysed using scanning electron microscopy (SEM). The valence band analysis showed the crystal field splitting of d states into doubly and triply degenerate states. H2 addition to the Ar plasma created additional d-state splitting due to distortions in the TiO2 structure by the Jahn–Teller mechanism. The occurrence of the Jahn–Teller split is well-correlated with oxygen vacancies in the TiO2−x
films. Water adsorption at the TiO2−x
surface and film hydroxylation were also addressed. The as-grown films were amorphous and SEM analysis showed a columnar structure for all the films but with a lower packing density of the columns after H2 introduction in the Ar plasma.
ATYPICAL SORSBY FUNDUS DYSTROPHY WITH A NOVEL TYR159CYS TIMP-3 MUTATION
Authors: Fung Adrian T. , Stöhr Heidi , Weber Bernhard H. F. , Holz Frank G. , Yannuzzi Lawrence A.
Published: August 2012

Purpose:

The purpose of this study was to report a patient with an atypical presentation of Sorsby fundus dystrophy.

Methods:

Retrospective chart review.

Results:

A 38-year-old man with a family history of Sorsby fundus dystrophy presented for ophthalmic examination. The patient had unilateral disease with an atypical appearance mimicking a pattern dystrophy. Molecular analysis of the TIMP-3 gene identified a Tyr159Cys mutation. He developed choroidal neovascularization, which was successfully treated with photodynamic therapy followed by intravitreal bevacizumab.

Conclusion:

Sorsby fundus dystrophy associated with a Tyr159Cys TIMP-3 point mutation may have a variable presentation. Intravitreal bevacizumab is useful in managing choroidal neovascularization associated with this condition.
Intralocus sexual conflict over human height
Authors: Stulp Gert , Kuijper Bram , Buunk Abraham P. , Pollet Thomas V. , Verhulst Simon
Published: August 2012

Intralocus sexual conflict (IASC) occurs when a trait under selection in one sex constrains the other sex from achieving its sex-specific fitness optimum. Selection pressures on body size often differ between the sexes across many species, including humans: among men individuals of average height enjoy the highest reproductive success, while shorter women have the highest reproductive success. Given its high heritability, IASC over human height is likely. Using data from sibling pairs from the Wisconsin Longitudinal Study, we present evidence for IASC over height: in shorter sibling pairs (relatively) more reproductive success (number of children) was obtained through the sister than through the brother of the sibling pair. By contrast, in average height sibling pairs most reproductive success was obtained through the brother relative to the sister. In conclusion, we show that IASC over a heritable, sexually dimorphic physical trait (human height) affects Darwinian fitness in a contemporary human population.