bluuebunny/crossref_metadata_2025 huggingface dataset:
Winds of Neptune: Voyager observations of cloud motions
Authors: Limaye Sanjay S. , Sromovsky Lawrence A.
Published: September 2012

High temporal and spatial resolution images acquired from Voyager cameras have been used to measure cloud motions to improve the meridional profile of the zonal mean circulation on Neptune. A wide range of atmospheric periods between 12 and 21 hours is revealed by the average cloud motions, consistent with the previous observations. New observations have expanded latitudinal coverage, improved the determination of streak motions, especially near 30°N, and added statistical weight to latitudes already covered by previous measurements. Both new and earlier observations have been subjected to quality control procedures to reduce dispersion caused by erroneous observations. The resulting data set emphasizes short time intervals to maximize target recognition. Most reliable cloud targets last less than one Neptune rotation, many only a fraction of it. A broad equatorial retrograde jet extends from approximately 50°S to at least 45°N (the northernmost latitude at which discrete cloud features have been seen). A relatively narrow prograde jet of at least 300 m s−1 is found near 70°S. The wind observations have a high degree of variability, some of which is due to variability of motions; but at many latitudes it reflects observation errors arising from rapid evolution of Neptune's clouds. A bias observed in the measured meridional component is most likely due to a small discrepancy between the true rotation pole of Neptune and the pole position used in the data reduction. Zonal motions and morphology suggest the global circulation to be symmetric about the equator.
The helium abundance of Neptune from Voyager measurements
Authors: Conrath B. J. , Gautier D. , Lindal G. F. , Samuelson R. E. , Shaffer W. A.
Published: September 2012

Voyager radio occultation and infrared spectrometer measurements are used to obtain an estimate of the helium abundance in the atmosphere of Neptune. It is found that the shape of the measured spectrum cannot be well matched by spectra calculated from atmospheric models that include only gaseous opacity. The most plausible explanation of the observed spectral shape appears to require the existence of an additional opacity source associated with clouds or hazes. The data can be fit with either a tropospheric or a stratospheric cloud model. If a tropospheric cloud is invoked, an optical thickness at 200 cm−1 between 1 and 8 is required, depending on the particle size assumed. For a stratospheric cloud an optical thickness between 0.2 and 0.8 is required. Optical constants for methane ice are used, but ethane has similar optical properties in this spectral region. Assuming no modification to the temperature profile is required other than a molecular weight adjustment, a combination of gas and cloud opacities produces a good fit to the spectrum for a helium mole fraction qHe = 0.190 ± 0.032, corresponding to a mass fraction Y = 0.32 ± 0.05. Within the measurement uncertainties the Neptune helium abundance may be compatible with that of Uranus and, marginally, with the protosolar value. However, models in which the outer part of the primitive solar nebular was enriched in CO and N2, leading to an enhanced atmospheric He/H2 ratio, cannot be ruled out at this time.
Voyager photometry of Triton: Haze and surface photometric properties
Authors: Hillier J. , Helfenstein P. , Verbiscer A. , Veverka J.
Published: September 2012

We have analyzed Voyager whole‐disk observations of Triton at violet (0.41 μm), blue (0.48 μm),and green (0.56 μm) filter wavelengths, using a model which combines an improved version of Hapke's photometric equation with a thin atmospheric haze layer in the appropriate spherical geometry. The model accurately describes the phase curves over a wide range of phase angles (10° ≤ α ≤ 159°) and agrees well with disk‐resolved brightness scans along the photometric equator and mirror meridian. An upturn in the phase curves seen at the highest phase angles observed (Smith et al., 1989) can be explained by including scattering in a thin atmospheric haze layer with optical depths ranging from 0.066 in the violet to 0.036 for the green filter data. The haze is forward scattering with g ∼ +0.6, requiring particle sizes of ≳0.2 μm. The haze single‐particle scattering albedo is near unity at all three wavelengths, suggesting the haze particles are relatively neutral ice condensates. The geometric albedo, phase integral, and spherical albedo of Triton in each filter corresponding to our best fit Hapke and atmospheric parameters are derived. The bolometric Bond albedo of Triton calculated from our results is 0.85 ± 0.05. If the 16‐μbar N2 atmosphere detected by the Voyager radio occultation experiment (Tyler et al., 1989) is in vapor equilibrium with the surface (therefore implying a surface temperature of 37.7 K), then our Bond albedo implies a surface emissivity of 0.46 ± 0.16.
The wavelength dependence of Triton's light curve
Authors: Hillier J. , Veverka J. , Helfenstein P. , McEwen A.
Published: September 2012

Using Voyager observations, we demonstrate that Triton's orbital light curve is strongly wavelength dependent, a characteristic which readily explains some of the apparent discrepancies among pre‐Voyager telescopic measurements. Specifically, we find a light curve amplitude (peak to peak) that decreases systematically with increasing wavelength from about 0.08 magnitude (peak to peak) near 200 nm to less than 0.02 magnitude near 1000 nm. Peak brightness occurs near 90° orbital longitude (leading hemisphere). The brightness variation across this hemisphere is close to sinusoidal; the variation across the darker hemisphere is more complex. The decrease in light curve amplitude with increasing wavelength appears to be due to a decrease in contrast among surface markings, rather than to atmospheric obscuration. Our model also explains the observed decrease in the amplitude of Triton's light curve at visible wavelengths over the past decade, a decrease related to the current migration of the subsolar latitude toward the south pole: we predict that this trend will continue into the 1990s.
CPT: Pharmacometrics and Systems Pharmacology
Authors: van der Graaf Piet H
Published: September 2012

Welcome to the first issue of CPT: Pharmacometrics and Systems Pharmacology (CPT:PSP), a new journal from the American Society for Clinical Pharmacology and Therapeutics. CPT:PSP is a cross‐disciplinary journal devoted to publishing advances in quantitative, model‐based approaches as applied in pharmacology, (patho)physiology, and disease to aid the discovery, development, and utilization of human therapeutics. The emphasis of CPT:PSP will be on the application of modeling and simulation and the impact of Pharmacometrics and Systems Pharmacology on the discovery and development of innovative therapies.

CPT: Pharmacometrics & Systems Pharmacology (2012) 1, e8; doi:10.1038/psp.2012.8; advance online publication 26 September 2012
Nitric oxide signalling pathway in Duchenne muscular dystrophy mice: up-regulation of L-arginine transporters
Authors: Ramachandran Jayalakshmi , Schneider Joel S. , Crassous Pierre-Antoine , Zheng Ruifang , Gonzalez James P. , Xie Lai-Hua , Beuve Annie , Fraidenraich Diego , Peluffo R. Daniel
Published: September 2012

DMD (Duchenne muscular dystrophy) is an incurable rapidly worsening neuromuscular degenerative disease caused by the absence of dystrophin. In skeletal muscle a lack of dystrophin disrupts the recruitment of neuronal NOS (nitric oxide synthase) to the sarcolemma thus affecting NO (nitric oxide) production. Utrophin is a dystrophin homologue, the expression of which is greatly up-regulated in the sarcolemma of dystrophin-negative fibres from mdx mice, a mouse model of DMD. Although cardiomyopathy is an important cause of death, little is known about the NO signalling pathway in the cardiac muscle of DMD patients. Thus we used cardiomyocytes and hearts from two month-old mdx and mdx:utrophin−/− (double knockout) mice (mdx:utr) to study key steps in NO signalling: L-arginine transporters, NOS and sGC (soluble guanylyl cyclase). nNOS did not co-localize with dystrophin or utrophin to the cardiomyocyte membrane. Despite this nNOS activity was markedly decreased in both mdx and mdx:utr mice, whereas nNOS expression was only decreased in mdx:utr mouse hearts, suggesting that utrophin up-regulation in cardiomyocytes maintains nNOS levels, but not function. sGC protein levels and activity remained at control levels. Unexpectedly, L-arginine transporter expression and function were significantly increased, suggesting a novel biochemical compensatory mechanism of the NO pathway and a potential entry site for therapeutics.
The Narrative Language Measures: Tools for Language Screening, Progress Monitoring, and Intervention Planning
Authors: Petersen Douglas B. , Spencer Trina D.
Published: September 2012

This authors of this article present a new language assessment, the Narrative Language Measures (NLM), designed for screening, progress monitoring, and intervention planning purposes. The authors examine NLM for its ability to satisfy the requirements of the assessment of language in a Response to Intervention (RTI) framework. Specifically, they describe the extent to which the NLM reflects socially important outcomes, involves standardized administration and scoring procedures, is time efficient and economical, has adequate psychometric properties, and is sensitive to language growth over time.
Five Principles to Consider When Providing Narrative Language Intervention to Children and Adolescents With Developmental Disabilities
Authors: Finestack Lizbeth H.
Published: September 2012

For many verbally expressive children and adolescents with developmental disabilities, it is important for speech-language pathologists to target narrative language skills in intervention. Although relatively little empirical evidence exists examining the narrative language profiles of children and adolescents with developmental disabilities, even less evidence exists evaluating narrative interventions for this population. Despite these limitations, drawing from research primarily involving adolescents with Down syndrome (DS), the author highlights five research-supported principles for clinicians to consider when designing and implementing narrative-focused interventions for individuals with developmental disabilities.
An Approach to Guiding and Supporting Decision-Making for Individuals With Dementia: Feeding, Swallowing, and Nutrition Considerations
Authors: Waters Sally Ouimet , Sullivan Paula A.
Published: September 2012

Feeding and swallowing issues are common occurrences in individuals with advanced dementia. Despite the near certainty that dysphagia will arise in the later stages of dementia, families and surrogates often remain unaware that these are natural occurrences in the disease process until the individual with dementia is in a critical state. The speech-language pathologist can best initiate family guidance for decision-making regarding oral intake early in the disease process and often at/near the onset of the dementia diagnosis. This may include using instrumental swallow evaluations at onset of diagnosis to establish baseline swallow function; monitoring of nutritional lab values such as prealbumin, which is predictive of overall state of health; using feeding scales and dementia rating scales; and eliciting patient/family perspectives. Periodic monitoring of the above stated factors from the onset of diagnosis and throughout the disease can facilitate the speech-language pathologist in guiding the family, surrogate, and medical team regarding oral intake in an individual with dementia. This may prevent the poor decision-making that often results from a crisis of severe dysphagia and/or weight loss in an individual with dementia.
Ingestion and Alzheimer's Disease: Evidence of Early Changes
Authors: Sheaffer Leah A. , Daniels Stephanie K.
Published: September 2012

Eating and swallowing are both impaired in Alzheimer's disease (AD). Research is limited in this area but has focused primarily on the late stages of the disease. A few studies have been completed in individuals with mild AD and reveal that changes begin early in the disease process, generally before an individual or family is aware of deficits. Further research is warranted to determine if treatment in the early stage of the disease can prolong safe, efficient, and independent feeding and swallowing.
The effect of the Perdew-Zunger self-interaction correction to density functionals on the energetics of small molecules
Authors: Klüpfel Simon , Klüpfel Peter , Jónsson Hannes
Published: September 2012

Self-consistent calculations using the Perdew-Zunger self-interaction correction (PZ-SIC) to local density and gradient dependent energy functionals are presented for the binding energy and equilibrium geometry of small molecules as well as energy barriers of reactions. The effect of the correction is to reduce binding energy and bond lengths and increase activation energy barriers when bond breaking is involved. The accuracy of the corrected functionals varies strongly, the correction to the binding energy being too weak for the local density approximation but too strong for the gradient dependent functionals considered. For the Perdew, Burke, and Ernzerhof (PBE) functional, a scaling of the PZ-SIC by one half gives improved results on average for both binding energy and bond lengths. The PZ-SIC does not necessarily give more accurate total energy, but it can result in a better cancellation of errors. An essential aspect of these calculations is the use of complex orbitals. A restriction to real orbitals leads to less accurate results as was recently shown for atoms [S. Klüpfel, P. Klüpfel, and H. Jónsson, Phys. Rev. A 84, 050501 (2011)10.1103/PhysRevA.84.050501]. The molecular geometry of radicals can be strongly affected by PZ-SIC. An incorrect, non-linear structure of the C2H radical predicted by PBE is corrected by PZ-SIC. The CH3 radical is correctly predicted to be planar when complex orbitals are used, while it is non-planar when the PZ-SIC calculation is restricted to real orbitals.
Quasi-monochromatic field-emission x-ray source
Authors: Diop Babacar , Binh Vu Thien
Published: September 2012

By favoring the L-peak emission over the bremsstrahlung part, direct quasi-monochromatic soft x-ray emission has been obtained with a field emission (FE) x-ray source. The electron impact x-ray setup uses an arrayed cathode of carbon nanopearl FE tips as a stable cold electron source within a vacuum of 10−6–10−7 Torr. The high brightness of the FE e-beam coupled with the array structure of the cold cathode allows a smoother control of the x-ray emission intensity. The wavelength of the x-ray source can be modified by the choice of target materials. Using Mo as the target material, the x-ray emission shows a peak centered at 2.45 keV with a monochromaticity between 75% and 55% and a FWHM in the range of 450 eV.
Magnetic and electronic properties of D22-Mn3Ge (001) films
Authors: Kurt H. , Baadji N. , Rode K. , Venkatesan M. , Stamenov P. , Sanvito S. , Coey J. M. D.
Published: September 2012

Oriented thin films of Mn3Ge with the tetragonal D022 structure, grown on strontium titanate substrates, exhibit a low magnetization Ms = 73 kA m−1 combined with high uniaxial anisotropy Ku = 0.91 MJ m−3 at 300 K, making them potentially useful for thermally stable sub-10 nm spin torque memory elements. The highly ordered epitaxial Mn3Ge (001) films show 46% diffusive spin polarization at the Fermi level, measured by point contact Andreev reflection. Density functional calculations show that the compounds are ferrimagnetic, with anisotropic spin polarization at the Fermi level.
Ca2+ solvation as a function of p, T, and pH from
ab initio
simulation
Authors: Adeagbo Waheed A. , Doltsinis Nikos L. , Burchard Michael , Maresch Walter V. , Fockenberg Thomas
Published: September 2012

First principles molecular dynamics simulations have been carried out at various temperatures and pressures starting with either Ca2+ or CaO in a reactive volume of 63 H2O molecules. In the case of aqueous Ca2+, the ion is surrounded by six H2O molecules in the first hydration shell at 300 K/0.3 GPa, with rare exchange between first and second hydrations shells. At 900 K/0.9 GPa, the coordination number in the first hydration shell fluctuates between six and eight, the average being 7.0. CaO immediately reacts with the surrounding H2O molecules to form Ca2+ + 2OH−. The hydroxyl ions form transient Ca(OH)+ and Ca(OH)2 complexes and have a mean residence time in the first coordination shell of Ca2+ of 6 ± 4 ps at 500 K and 3 ± 3 ps at 900 K, respectively. At 500 K/0.5 GPa, the time-averaged relative concentrations of the transient Ca2+, Ca(OH)+, and Ca(OH)2 species are 14%, 55%, and 29%, while at 900 K/0.9 GPa, they are 2%, 34%, and 63%.
Performance analysis of a micro-scaled quantum Stirling refrigeration cycle
Authors: Lin Bihong , Huang Zhifu , Chen Jincan
Published: September 2012

The cycle model of a general micro-scaled regenerative quantum refrigerator working with an ideal Bose or Fermi gas is established. The combined effects of quantum boundary and degeneracy on the performance of the cycle are investigated based on the thermodynamic properties of a confined ideal Bose or Fermi gas. The inherent regenerative losses of the cycle are analyzed and calculated. Expressions for several important performance parameters, such as the refrigeration load, work input, and coefficient of performance (COP), are derived under the cases of the gas degeneracy, weak gas degeneracy, high temperature limit, and thermodynamic limit. The curves of the refrigeration load and coefficient of performance versus the volume and surface area ratios of the cycle and the refrigeration load versus the coefficient of performance are represented. The effects of the size effect on the refrigeration load and coefficient of performance are discussed. The general performance characteristics of the cycle are revealed. It is found that both the refrigeration load and coefficient of performance of the micro-scaled quantum Stirling refrigeration cycle depend on the surface area of the cyclic system besides the temperature of the heat reservoirs, the volume of cyclic system, and other parameters, while those of the macro-scaled refrigerator are independent of the surface area of a cyclic system. The results obtained here are more general and significant than those in the current literature.
Effects of Co content on the structural, luminescence, and ferromagnetic properties of Zn1−xCoxSy films
Authors: Ni Wei-Shih , Lin Yow-Jon
Published: September 2012

This study investigates the effect of Co content on the structural, luminescence, and ferromagnetic properties of sol-gel Zn1−xCoxSy films by x-ray diffraction, photoluminescence, energy dispersive spectrometer, atomic force microscopy, and alternating gradient magnetometer measurements. It is shown that Co doping may lead to weakened intensity of the defect-related luminescence and the intensity of the defect-related luminescence decreases with increasing Co content. Changes in Co concentration are important issues for improving crystal quality of ZnS films. It is also found that the defects play important roles in determining the ferromagnetic characteristics of the Zn1−xCoxSy films.
A model for internal photoemission at high-k oxide/silicon energy barriers
Authors: Engström O.
Published: September 2012

A model has been developed to describe the emission of electrons from silicon across the oxide energy barrier of metal-oxide-silicon structures. An optical absorption coefficient, exclusively describing the transmission of electrons which are emitted across the barrier, is split from the corresponding experimental quantity for the entire absorption range. This makes it possible to approximate the photo yield in terms of absorption coefficients and density of states without need for explicitly calculated matrix elements of optical transitions. Using this method, theoretical emission yield curves are found in good agreement with measured data. An important conclusion from this work is that values of oxide energy barrier heights should be extracted from different features of the yield data than most often done in the literature. This replaces a commonly used practice for determining the barrier heights, which is shown to be based on optical bulk properties of the silicon crystal.
Tuning luminescence properties of silicon nanocrystals by lithium doping
Authors: Klimešová E. , Kůsová K. , Vacík J. , Holý V. , Pelant I.
Published: September 2012

Doping silicon nanocrystals (SiNCs) provides a new way to modify their luminescence properties and tailor them for a particular application. We prepared Li-doped SiNCs and characterized them by neutron depth profiling and x-ray diffraction. Our SiNC samples are doped with around 10–100 Li atoms per one nanocrystal and their lattice slightly expands after lithium insertion. We show that the photoluminescence (PL) properties of Li-doped SiNCs are distinctly modified compared to the undoped case. The PL maximum shifts to shorter wavelengths and the PL decay time decreases, both these features being favorable for applications in photonics. The spectral blue-shift is attributed to the tensile strain in SiNCs induced by doping with lithium.
Counting statistics for genetic switches based on effective interaction approximation
Authors: Ohkubo Jun
Published: September 2012

Applicability of counting statistics for a system with an infinite number of states is investigated. The counting statistics has been studied a lot for a system with a finite number of states. While it is possible to use the scheme in order to count specific transitions in a system with an infinite number of states in principle, we have non-closed equations in general. A simple genetic switch can be described by a master equation with an infinite number of states, and we use the counting statistics in order to count the number of transitions from inactive to active states in the gene. To avoid having the non-closed equations, an effective interaction approximation is employed. As a result, it is shown that the switching problem can be treated as a simple two-state model approximately, which immediately indicates that the switching obeys non-Poisson statistics.
Implications of nanostructuring on the thermoelectric properties in half-Heusler alloys
Authors: Bhardwaj A. , Misra D. K. , Pulikkotil J. J. , Auluck S. , Dhar A. , Budhani R. C.
Published: September 2012

High energy ball milled Zr0.25Hf0.75NiSn alloys subjected to spark plasma sintering show an enhanced thermoelectric figure of merit in comparison with its normal bulk material synthesized by arc-melting process. The enhancement is due to increase in Seebeck coefficient with simultaneous decrease in thermal conductivity which follows due to increase in the cell volume. Theoretical calculations find that volume expansion facilitates band narrowing effects leading to high Seebeck coefficient and that decreasing orbital overlap which results in weak bonding leads to dampening the phonon propagation in addition to the interface scattering of phonons from phase boundaries.
Magnetostriction of TbFe2-based alloy treated in a semi-solid state with a high magnetic field
Authors: Wang Qiang , Liu Yin , Liu Tie , Gao Pengfei , Wang Kai , He Jicheng
Published: September 2012

We investigated the effect of a high magnetic field on the magnetostriction of TbFe2-based alloy during a semi-solid state process. With the application of a high magnetic field, magnetostrictions under free and compressive prestress conditions remarkably increased. Obvious magnetically anisotropic behavior of the TbFe2-based alloy was observed. A high 〈111〉 orientation of TbFe2 phase along the magnetic-field direction was produced. The increase in magnetostriction and the magnetically anisotropic behavior were attributed to the 〈111〉 orientation of TbFe2 phase during the treatment in the semi-solid state induced by the magnetic field.
Feedback cooling of cantilever motion using a quantum point contact transducer
Authors: Montinaro M. , Mehlin A. , Solanki H. S. , Peddibhotla P. , Mack S. , Awschalom D. D. , Poggio M.
Published: September 2012

We use a quantum point contact (QPC) as a displacement transducer to measure and control the low-temperature thermal motion of a nearby micromechanical cantilever. The QPC is included in an active feedback loop designed to cool the cantilever's fundamental mechanical mode, achieving a squashing of the QPC noise at high gain. The minimum achieved effective mode temperature of 0.2 K and the displacement resolution of 10−11 m/Hz are limited by the performance of the QPC as a one-dimensional conductor and by the cantilever-QPC capacitive coupling.
Protocols for characterising quantum transport through nano-structures
Authors: Sen Sudeshna , Vidhyadhiraja N. S.
Published: September 2012

In this work, we have analysed the exact closed-form solutions for transport quantities through a mesoscopic region which may be characterised by a polynomial functional of resonant transmission functions. These are then utilized to develop considerably improved protocols for parameters relevant for quantum transport through molecular junctions and quantum dots. The protocols are shown to be experimentally feasible and should yield the parameters at much higher resolution than the previously proposed ones.
Snow cleaning of substrates increases yield of large-area organic photovoltaics
Authors: Wang Nana , Zimmerman Jeramy D. , Tong Xiaoran , Xiao Xin , Yu Junsheng , Forrest Stephen R.
Published: September 2012

We demonstrate large-area organic photovoltaic cells (OPVs) based on boron-subphthalocyanine chloride (SubPc)/C60 and 2,4-bis[4-(N,N-diphenylamino)-2,6 dihydroxyphenyl]squaraine/C60 heterojunctions on substrates “snow-cleaned” with a jet of mixed-phase CO2. Snow cleaning reduces particulates on the indium-tin-oxide (ITO)-coated glass substrates, thereby reducing device shorts and shunt paths. Snow cleaning improves yield of 1.44 cm2 SubPc/C60 OPV cells from zero for conventionally solvent-cleaned substrates to ∼70%. The standard deviation of power conversion efficiency for a population of 19 snow-cleaned devices is ≤4.0%. By using a sub-electrode structure, we obtain a power conversion efficiency of 2.21% ± 0.05% for 6.25 cm2 SubPc/C60 devices, compared to 2.69% ± 0.03%, for 0.008 cm2 devices, with the efficiency decrease due to series resistance of the ITO.
Phase-field modeling of stress generation in electrode particles of lithium ion batteries
Authors: Huttin Magalie , Kamlah Marc
Published: September 2012

Many cathode materials in lithium ion batteries show capacity fade due to particle crackings even at low applied charge and discharge current (C-rate). The promising candidate material LixMn2O4 exhibits such effects on the 4 V-plateau when the state of charge 0<x<1, hence the crystalline host remains cubic spinel. Single particle failure in this range of values indicates the existence of very large stresses, which may occur due to phase segregation. In this letter, we employ a phase-field model coupled to mechanics to demonstrate the relationship between phase segregation and high values of the mechanical stresses thus explaining numerous experimental results.
Direct observation of the terahertz optical free induction decay of molecular rotation absorption lines in the sub-nanosecond time scale
Authors: Chesnokov E. N. , Kubarev V. V. , Koshlyakov P. V. , Kulipanov G. N.
Published: September 2012

Optical free induction decay (FID) in the region of 60–75 cm−1 was detected using 120 ps pulses of free electron laser. Signals were detected in real time using ultra-fast Schottky diode detectors. The oscillations corresponding to the splitting of absorption lines in deuterated water vapor (Δf = 0.15 cm−1) and hydrogen bromide (Δf = 0.02 cm−1) were detected. At high optical density, we observed the oscillations arising from “top-hat” shape of absorption lines. Free induction decay signals could be detected in a single shot. This observation allowed obtaining a spectrum in one laser pulse, which facilitates studies of very fast processes.
White top-emitting organic light-emitting diodes employing tandem structure
Authors: Wang Qiang , Chen Yonghua , Chen Jiangshan , Ma Dongge
Published: September 2012

A high-efficiency white top-emitting organic light-emitting diode (TOLED) is demonstrated by introducing tandem structure. The microcavity effects are used to finalize the configuration of the tandem white TOLED. The resultant tandem white TOLED emits a complementary-color white light with the Commission Internationale de L'Eclairage coordinates of (0.39, 0.43) and the color-rendering index of 70, which retains high color stability towards driving voltage. The maximum forward viewing external quantum efficiency and current efficiency of the device are 16.9% and 41.1 cd/A, respectively. The employment of the tandem structure can be an alternative method to fabricate white TOLEDs for practical applications.
Ultra-highly sensitive surface-corrugated microfiber Bragg grating force sensor
Authors: Luo Wei , Kou Jun-long , Chen Ye , Xu Fei , Lu Yan-qing
Published: September 2012

We experimentally demonstrate a microfiber Bragg grating force sensor with ultra-high sensitivity. The fiber Bragg grating (FBG) is inscribed in a microfiber tapered from standard non-photosensitive single-mode fiber by focused ion beam machining method, and has a compact size (∼112 μm in length). Small diameter increases the force sensitivity of such grating when acting as a force-sensing element under tensile loads. We have demonstrated force sensitivity as high as ∼3146 nm/N around the resonant wavelength of 1538 nm, which is three orders of magnitude larger than FBGs in untapered fibers.
Sandwiching intermediate reflectors in tandem solar cells for improved photon management
Authors: Fahr Stephan , Rockstuhl Carsten , Lederer Falk
Published: September 2012

In tandem solar cells, intermediate reflectors are employed to increase light absorption in the top cell. Thus far, the use of photonic crystals for this purpose was not optimal since side-lobes in the reflection spectrum reduced the absorption in the bottom cell. To compensate this reduction, the bottom cell thickness had to be excessively increased; nullifying the main advantage of thin-film solar cells. Here, we suggest to solve this issue by reducing the impedance mismatch between photonic crystal and bottom cell using anti-reflection layers. The concept is even validated for solar cells comprising random textures.
Ferroelectric vs. structural properties of large-distance sputtered epitaxial LSMO/PZT heterostructures
Authors: Leufke Philipp M. , Kruk Robert , Wang Di , Kübel Christian , Hahn Horst
Published: September 2012

We report on large-distance rf-magnetron sputtering as a competitive alternative to pulsed laser deposition and off-axis sputtering for the growth of epitaxial PbZr0.52Ti0.48O3 (PZT) thin films. To determine the characteristics of the PZT films, the studies were focused on the interplay between microstructural and ferroelectric properties. The films were deposited on insulating or conducting (Nb-doped) SrTiO3 and MgO substrates with La0.83Sr0.17MnO3 as bottom electrode. The uniformity and homogeneity of the samples was demonstrated by using large area (1.0 mm2) top electrodes. It is shown that epitaxial heterostructures of excellent crystalline and ferroelectric quality can be deposited from a stoichiometric PZT target without the need for excess PbO in the target or post-annealing of the samples.
Static and Dynamic Aspects of Supramolecular Interactions of Coumarin 153 and Fluorescein with Bovine Serum Albumin
Authors: Yadav Rajeev , Das Shyamashis , Sen Pratik
Published: September 2012

The static and dynamic aspects of supramolecular interactions between coumarin 153 (C153) and fluorescein (FL) with bovine serum albumin (BSA) has been studied by spectroscopic techniques. Both dyes were found to form 1 : 1 complexes with BSA, with binding constants 2.9 ± 0.3 × 105 M–1 and 2.1 ± 0.2 × 105 M–1 for C153 and FL respectively. The binding site of C153 has been determined by steady-state fluorescence resonance energy transfer, site marker competitive experiments, and a molecular docking study. Our studies indicate that C153 binds to domain IIIA of BSA whereas FL binds non-specifically. Denaturation characteristics of the C153 and FL binding region of BSA were found to be very different to global denaturation. Furthermore, kinetics of binding has been studied by the stopped-flow method. The observed rate constants were found to be 8.8 s–1 and 5.9 s–1 for C153 and FL respectively.
Structural Insights into the Active Site of Human Sodium Dependent Glucose Co-Transporter 2: Homology Modelling, Molecular Docking, and 3D - QSAR Studies
Authors: Nakka Srinivas , Guruprasad Lalitha
Published: September 2012

Human sodium dependent glucose co-transporter 2 (hSGLT2) is a target for diabetes mellitus type 2 (T2DM). The 3D (three dimensional) homology model of hSGLT2 comprising 14 transmembrane helical domains was constructed and molecular docking of the inhibitors, C-aryl glucoside analogues, into the active site was studied. The 3D-QSAR (quantitative structure activity relationship) analysis was carried out on 43 C-aryl glucoside analogues as a training set. The molecular field analysis (MFA) with G/PLS (genetic partial least-squares) method was used to generate statistically significant 3D-QSAR (r2 = 0.857) based on a molecular field generated using electrostatic and steric probes. The QSAR model was validated using leave-one-out cross-validation, bootstrapping, and randomisation methods, and finally with an external test set comprising 10 inhibitors. The molecular docking studies provide structural insights into the active site and key interactions involved in the binding of inhibitors to hSGLT2 and these results corroborate with the 3D-QSAR analysis that provide the active conformation of inhibitors and the nature of interactive fields important for activity.
Transcription Inhibition by Organometallic Ruthenium - Arene Anticancer Complexes in Live Mammalian Cells
Authors: Astarina Astrid , Chow Mun Juinn , Ang Wee Han
Published: September 2012

Organometallic ruthenium–arene RAPTA complexes, currently being actively pursued as potential anticancer agents, interact with intracellular biological targets to form covalent adducts. Because their mode of action is still unclear, we investigated their binding with DNA and the ability of ruthenated-DNA adducts to elicit cellular responses such as transcription inhibition and repair. To investigate the influence of the spectator arene ligands on RAPTA activity, a novel RAPTA complex containing the bulky 1,3,5-triisopropylbenzene ligand was synthesized and characterized. Transcription experiments carried out in live mammalian cells using ruthenated plasmid probes revealed that increasing steric bulk of the arene ligand did not improve its ability to arrest transcription.
Regioselective Addition of 1,3-Dicarbonyl Dianions to Carbonyl Compounds: One Pot Lactonization and Ketalization of δ-Hydroxy-β-keto Esters to Protected Pyrone Derivatives
Authors: Ghorai Manas K. , Halder Sandipan , Samanta Sauvik
Published: September 2012

A simple and efficient strategy for the synthesis of 6-substituted-2-pyrone derivatives, by BF3·OEt2 mediated one pot cyclization and keto-protection of δ-hydroxy-β-keto esters, obtained via regioselective addition of 1,3-dicarbonyl dianion of ethyl acetoacetate to aldehydes and ketones is described.
Magnetic Dipole Origins of the 3A2g→3T2g Transition in Ni(II) Doped MgO
Authors: Riley Mark J. , Hall Jeremy , Krausz Elmars R.
Published: September 2012

Magnetic circular dichroism and magnetic linear dichroism spectroscopy have been used to study the near infrared 3A2g → 3T2g transition of Ni(ii) doped MgO. Two sharp electronic origins are observed and it is show that their polarisation behaviour follows that expected from calculations in detail for magnetic dipole allowed transitions in octahedral symmetry. Not all transitions to the spin-orbit components of the 3T2g state are observed. We put forward an explanation for why some components are missing, even though they are expected to be of comparable intensity, in terms of the different coupling to the Jahn–Teller active tetragonal distortion in the excited state. The two lower energy spin-orbit split components are nearly independent of this distortion, while the two higher energy components are strongly dependent. We also examine the double quantum transition in the electron paramagnetic resonance spectrum and estimate the magnitude of the random strain of tetragonal symmetry in the MgO lattice.
Pyridine-Incorporated Dihexylquaterthiophene: A Novel Blue Emitter for Organic Light Emitting Diodes (OLEDs)
Authors: Sonar Prashant , Santamaria Sonsoles Garcia , Lin Ting Ting , Sellinger Alan , Bolink Henk
Published: September 2012

The synthesis and characterisation of 2,5-bis(5′-hexyl-[2,2′-bithiophen]-5-yl)pyridine (Th4PY) and its use as a blue emitter in organic light emitting diodes (OLEDs) is reported. Th4PY was synthesised in high yield using a straightforward Suzuki coupling route with commercially available starting materials. As Th4PY is both soluble and has low molecular weight, blue OLEDs were fabricated using both spin-coating and vacuum deposition thin film processing techniques to study the effect of processing on device performance. OLED devices using a spin-coated layer consisting of 4′,4′′-tris(N-carbazolyl)triphenylamine (TCTA) and 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as a host matrix together with Th4PY as emitter exhibited highly efficient sky-blue emission with a low turn-on voltage of 3 V, a maximum brightness close to 15000 cd m–2 at 8 V, and a maximum luminous efficiency of 7.4 cd A–1 (6.3 lm W–1) with CIE coordinates of x = 0.212, y = 0.320. The device performance characteristics are compared using various matrices and processing techniques. The promising sky-blue OLED performance, solution processability, and ambient stability make Th4PY a promising blue emitter for application in OLEDs.
Therapeutic stem cells expressing variants of EGFR-specific nanobodies have antitumor effects
Authors: van de Water Jeroen A. J. M. , Bagci-Onder Tugba , Agarwal Aayush S. , Wakimoto Hiroaki , Roovers Rob C. , Zhu Yanni , Kasmieh Randa , Bhere Deepak , Van Bergen en Henegouwen Paul M. P. , Shah Khalid
Published: September 2012

The deregulation of the epidermal growth factor receptor (EGFR) has a significant role in the progression of tumors. Despite the development of a number of EGFR-targeting agents that can arrest tumor growth, their success in the clinic is limited in several tumor types, particularly in the highly malignant glioblastoma multiforme (GBM). In this study, we generated and characterized EGFR-specific nanobodies (ENb) and imageable and proapoptotic ENb immunoconjugates released from stem cells (SC) to ultimately develop a unique EGFR-targeted therapy for GBM. We show that ENbs released from SCs specifically localize to tumors, inhibit EGFR signaling resulting in reduced GBM growth and invasiveness in vitro and in vivo in both established and primary GBM cell lines. We also show that ENb primes GBM cells for proapoptotic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Furthermore, SC-delivered immunoconjugates of ENb and TRAIL target a wide spectrum of GBM cell types with varying degrees of TRAIL resistance and significantly reduce GBM growth and invasion in both established and primary invasive GBM in mice. This study demonstrates the efficacy of SC-based EGFR targeted therapy in GBMs and provides a unique approach with clinical implications.
NMDA receptor function in large-scale anticorrelated neural systems with implications for cognition and schizophrenia
Authors: Anticevic Alan , Gancsos Mark , Murray John D. , Repovs Grega , Driesen Naomi R. , Ennis Debra J. , Niciu Mark J. , Morgan Peter T. , Surti Toral S. , Bloch Michael H. , Ramani Ramachandran , Smith Mark A. , Wang Xiao-Jing , Krystal John H. , Corlett Philip R.
Published: September 2012

Glutamatergic neurotransmission mediated by
N
-methyl-
d
-aspartate (NMDA) receptors is vital for the cortical computations underlying cognition and might be disrupted in severe neuropsychiatric illnesses such as schizophrenia. Studies on this topic have been limited to processes in local circuits; however, cognition involves large-scale brain systems with multiple interacting regions. A prominent feature of the human brain’s global architecture is the anticorrelation of default-mode vs. task-positive systems. Here, we show that administration of an NMDA glutamate receptor antagonist, ketamine, disrupted the reciprocal relationship between these systems in terms of task-dependent activation and connectivity during performance of delayed working memory. Furthermore, the degree of this disruption predicted task performance and transiently evoked symptoms characteristic of schizophrenia. We offer a parsimonious hypothesis for this disruption via biophysically realistic computational modeling, namely cortical disinhibition. Together, the present findings establish links between glutamate’s role in the organization of large-scale anticorrelated neural systems, cognition, and symptoms associated with schizophrenia in humans.
β-Arrestin-2 mediates the proinflammatory effects of proteinase-activated receptor-2 in the airway
Authors: Nichols Heddie L. , Saffeddine Mahmoud , Theriot Barbara S. , Hegde Akhil , Polley Daniel , El-Mays Tamer , Vliagoftis Harissios , Hollenberg Morley D. , Wilson Emma H. , Walker Julia K. L. , DeFea Kathryn A.
Published: September 2012

Proteinase-Activated rreceptor-2 (PAR2), a G-protein–coupled Receptor, activated by serine proteinases, is reported to have both protective and proinflammatory effects in the airway. Given these opposing actions, both inhibitors and activators of PAR2have been proposed for treating asthma. PAR2can signal through two independent pathways: a β-arrestin–dependent one that promotes leukocyte migration, and a G-protein/Ca2+one that is required for prostaglandin E2(PGE2) production and bronchiolar smooth muscle relaxation. We hypothesized that the proinflammatory responses to PAR2activation are mediated by β-arrestins, whereas the protective effects are not. Using a mouse ovalbumin model for PAR2-modulated airway inflammation, we observed decreased leukocyte recruitment, cytokine production, and mucin production in β-arrestin-2−/−mice. In contrast, PAR2-mediated PGE2production, smooth muscle relaxation, and decreased baseline airway resistance (measures of putative PAR2“protective” effects) were independent of β-arrestin-2. Flow cytometry and cytospins reveal that lung eosinophil and CD4 T-cell infiltration, and production of IL-4, IL-6, IL-13, and TNFα, were enhanced in wild-type but not β-arrestin-2−/−mice. Using the forced oscillation technique to measure airway resistance reveals that PAR2activation protects against airway hyperresponsiveness by an unknown mechanism, possibly involving smooth muscle relaxation. Our data suggest that the PAR2-enhanced inflammatory process is β-arrestin-2 dependent, whereas the protective anticonstrictor effect of bronchial epithelial PAR2may be β-arrestin independent.
Recommendations for Catch-Curve Analysis
Authors: Smith Matthew W. , Then Amy Y. , Wor Catarina , Ralph Gina , Pollock Kenneth H. , Hoenig John M.
Published: September 2012

Three common cross-sectional catch-curve methods for estimating total mortality rate (Z) are the Chapman–Robson, regression, and Heincke estimators. There are five unresolved methodological issues: (1) which is the best estimator, (2) how one should determine the first age-group to use in the analysis, (3) how the variance estimators perform; and, for regression estimators, (4) how the observations should be weighted, including (5) whether and how the oldest ages should be truncated. We used analytical methods and Monte Carlo simulation to evaluate the three catch-curve methods, including unweighted and weighted versions of the regression estimator. We evaluated four criteria for specifying the first age-class used. Regression estimators were evaluated with four different methods of right data truncation. Heincke's method performed poorly and is generally not recommended. The two-tailed χ2 test and one-tailed z-test for full selectivity described by Chapman and Robson did not perform as well as simpler criteria and are not recommended. Estimates with the lowest mean square error were generally provided by (1) the Chapman–Robson estimator with the age of full recruitment being the age of maximum catch plus 1 year and (2) the weighted regression estimator with the age of full recruitment being the age of maximum catch and with no right truncation. Differences in performance between the two methods were small (<6% of Z). The Chapman–Robson estimator of the variance of had large negative bias when not corrected for overdispersion; once corrected, it performed as well as or better than all other variance estimators evaluated. The regression variance estimator is generally precise and slightly negatively biased. We recommend that the traditional Chapman–Robson approach be corrected for overdispersion and used routinely to estimate Z. Weighted linear regression may work slightly better but is completely ad hoc. Unweighted linear regression should no longer be used for analyzing catch-curve data.

Received November 30, 2011; accepted July 4, 2012
Biological versus electronic adaptive coloration: how can one inform the other?
Authors: Kreit Eric , Mäthger Lydia M. , Hanlon Roger T. , Dennis Patrick B. , Naik Rajesh R. , Forsythe Eric , Heikenfeld Jason
Published: September 2012

Adaptive reflective surfaces have been a challenge for both electronic paper (e-paper) and biological organisms. Multiple colours, contrast, polarization, reflectance, diffusivity and texture must all be controlled simultaneously without optical losses in order to fully replicate the appearance of natural surfaces and vividly communicate information. This review merges the frontiers of knowledge for both biological adaptive coloration, with a focus on cephalopods, and synthetic reflective e-paper within a consistent framework of scientific metrics. Currently, the highest performance approach for both nature and technology uses colourant transposition. Three outcomes are envisioned from this review: reflective display engineers may gain new insights from millions of years of natural selection and evolution; biologists will benefit from understanding the types of mechanisms, characterization and metrics used in synthetic reflective e-paper; all scientists will gain a clearer picture of the long-term prospects for capabilities such as adaptive concealment and signalling.
The asymptotic theory of dispersion relations containing Bessel functions of imaginary order
Authors: Chapman C. J.
Published: September 2012

This paper presents a method of analysing wave-field dispersion relations in which Bessel functions of imaginary order occur. Such dispersion relations arise in applied studies in oceanography and astronomy, for example. The method involves the asymptotic theory developed by Dunster in 1990, and leads to simple analytical approximations containing only trigonometric and exponential functions. Comparisons with accurate numerical calculations show that the resulting approximations to the dispersion relation are highly accurate. In particular, the approximations are powerful enough to reveal the fine structure in the dispersion relation and so identify different wave regimes corresponding to different balances of physical processes. Details of the method are presented for the fluid-dynamical problem that stimulated this analysis, namely the dynamics of an internal ocean wave in the presence of an aerated surface layer; the method identifies and gives different approximations for the subcritical, supercritical and critical regimes. The method is potentially useful in a wide range of problems in wave theory and stability theory. A mathematical theme of the paper is that of the removable singularity.