bluuebunny/crossref_metadata_2025 huggingface dataset:
A variant of the Kochen-Specker theorem localising value indefiniteness
Authors: Abbott Alastair A. , Calude Cristian S. , Svozil Karl
Published: October 2015

The Kochen-Specker theorem proves the inability to assign, simultaneously, noncontextual definite values to all (of a finite set of) quantum mechanical observables in a consistent manner. If one assumes that any definite values behave noncontextually, one can nonetheless only conclude that some observables (in this set) are value indefinite. In this paper, we prove a variant of the Kochen-Specker theorem showing that, under the same assumption of noncontextuality, if a single one-dimensional projection observable is assigned the definite value 1, then no one-dimensional projection observable that is incompatible (i.e., non-commuting) with this one can be assigned consistently a definite value. Unlike standard proofs of the Kochen-Specker theorem, in order to localise and show the extent of value indefiniteness, this result requires a constructive method of reduction between Kochen-Specker sets. If a system is prepared in a pure state ψ, then it is reasonable to assume that any value assignment (i.e., hidden variable model) for this system assigns the value 1 to the observable projecting onto the one-dimensional linear subspace spanned by ψ, and the value 0 to those projecting onto linear subspaces orthogonal to it. Our result can be interpreted, under this assumption, as showing that the outcome of a measurement of any other incompatible one-dimensional projection observable cannot be determined in advance, thus formalising a notion of quantum randomness.
An accurate full-dimensional potential energy surface for H–Au(111): Importance of nonadiabatic electronic excitation in energy transfer and adsorption
Authors: Janke Svenja M. , Auerbach Daniel J. , Wodtke Alec M. , Kandratsenka Alexander
Published: October 2015

We have constructed a potential energy surface (PES) for H-atoms interacting with fcc Au(111) based on fitting the analytic form of the energy from Effective Medium Theory (EMT) to ab initio energy values calculated with density functional theory. The fit used input from configurations of the H–Au system with Au atoms at their lattice positions as well as configurations with the Au atoms displaced from their lattice positions. It reproduces the energy, in full dimension, not only for the configurations used as input but also for a large number of additional configurations derived from ab initio molecular dynamics (AIMD) trajectories at finite temperature. Adiabatic molecular dynamics simulations on this PES reproduce the energy loss behavior of AIMD. EMT also provides expressions for the embedding electron density, which enabled us to develop a self-consistent approach to simulate nonadiabatic electron-hole pair excitation and their effect on the motion of the incident H-atoms. For H atoms with an energy of 2.7 eV colliding with Au, electron-hole pair excitation is by far the most important energy loss pathway, giving an average energy loss ≈3 times that of the adiabatic case. This increased energy loss enhances the probability of the H-atom remaining on or in the Au slab by a factor of 2. The most likely outcome for H-atoms that are not scattered also depends prodigiously on the energy transfer mechanism; for the nonadiabatic case, more than 50% of the H-atoms which do not scatter are adsorbed on the surface, while for the adiabatic case more than 50% pass entirely through the 4 layer simulation slab.
A trap-based pulsed positron beam optimised for positronium laser spectroscopy
Authors: Cooper B. S. , Alonso A. M. , Deller A. , Wall T. E. , Cassidy D. B.
Published: October 2015

We describe a pulsed positron beam that is optimised for positronium (Ps) laser-spectroscopy experiments. The system is based on a two-stage Surko-type buffer gas trap that produces 4 ns wide pulses containing up to 5 × 105 positrons at a rate of 0.5-10 Hz. By implanting positrons from the trap into a suitable target material, a dilute positronium gas with an initial density of the order of 107 cm−3 is created in vacuum. This is then probed with pulsed (ns) laser systems, where various Ps-laser interactions have been observed via changes in Ps annihilation rates using a fast gamma ray detector. We demonstrate the capabilities of the apparatus and detection methodology via the observation of Rydberg positronium atoms with principal quantum numbers ranging from 11 to 22 and the Stark broadening of the n = 2 → 11 transition in electric fields.
Creation of cold nitric oxide by extraction of the cold fraction of a thermal distribution
Authors: Bichsel Bryan J. , Alexander Jason , Dahal Parshuram , Morrison Michael A. , Shafer-Ray Neil E. , Abraham E. R. I.
Published: October 2015

We describe a device using the Stark effect to extract the cold fraction of nitric oxide molecules from a warmer thermal distribution. Room temperature NO is cryogenically cooled to 72-82 K and injected into a straight, hexapole guide that uses the Stark effect. By blocking line-of-sight trajectories from the input to the output, primarily the slowest molecules are guided around the obstruction and are transferred into a new chamber. We measure the temperature distribution using a field-stabilized Rydberg time-of-flight technique. A superposition of molecular Rydberg states is excited, sufficiently increasing the lifetime of the excited state for a time-of-flight measurement for cold molecular samples. We produce a continuous source of nitric oxide with temperatures ranging from 7 to 20 K in the lowest ro-vibrational state. The output temperature is controlled by the initial temperature distribution and the guide voltage.
Ge1−x−ySixSny light emitting diodes on silicon for mid-infrared photonic applications
Authors: Gallagher J. D. , Xu C. , Senaratne C. L. , Aoki T. , Wallace P. M. , Kouvetakis J. , Menéndez J.
Published: October 2015

This paper reports initial the demonstration of prototype Ge1−x−ySixSny light emitting diodes with distinct direct and indirect edges and high quality I-V characteristics. The devices are fabricated on Si (100) wafers in heterostructure pin geometry [n-Ge/i-Ge1−x−ySixSny/p-Ge(Sn/Si)] using ultra low-temperature (T < 300 °C) depositions of the highly reactive chemical sources Si4H10, Ge4H10, Ge3H8, and SnD4. The Sn content in the i-Ge1−x−ySixSny layer was varied from ∼3.5% to 11%, while the Si content was kept constant near 3%. The Si/Sn amounts in the p-layer were selected to mitigate the lattice mismatch so that the top interface grows defect-free, thereby reducing the deleterious effects of mismatch-induced dislocations on the optical/electrical properties. The spectral responsivity plots of the devices reveal sharp and well-defined absorption edges that systematically red-shift in the mid-IR from 1750 to 2100 nm with increasing Sn content from 3.5% to 11%. The electroluminescence spectra reveal strong direct-gap emission peaks and weak lower energy shoulders attributed to indirect gaps. Both peaks in a given spectrum red-shift with increasing Sn content and their separation decreases as the material approaches direct gap conditions in analogy with binary Ge1−ySny counterparts. These findings-combined with the enhanced thermal stability of Ge1−x−ySixSny relative to Ge1−ySny and the observation that ternary alloy disorder does not adversely affect the emission properties—indicate that Ge1−x−ySixSny may represent a practical target system for future generations of group-IV light sources on Si.
Charged particle flows in the beam extraction region of a negative ion source for NBI
Authors: Geng S. , Tsumori K. , Nakano H. , Kisaki M. , Ikeda K. , Osakabe M. , Nagaoka K. , Takeiri Y. , Shibuya M. , Kaneko O.
Published: October 2015

Experiments by a four-pin probe and photodetachment technique were carried out to investigate the charged particle flows in the beam extraction region of a negative hydrogen ion source for neutral beam injector. Electron and positive ion flows were obtained from the polar distribution of the probe saturation current. Negative hydrogen ion flow velocity and temperature were obtained by comparing the recovery times of the photodetachment signals at opposite probe tips. Electron and positive ions flows are dominated by crossed field drift and ambipolar diffusion. Negative hydrogen ion temperature is evaluated to be 0.12 eV.
Accurate measurements and temperature dependence of the water vapor self-continuum absorption in the 2.1 μm atmospheric window
Authors: Ventrillard I. , Romanini D. , Mondelain D. , Campargue A.
Published: October 2015

In spite of its importance for the evaluation of the Earth radiative budget, thus for climate change, very few measurements of the water vapor continuum are available in the near infrared atmospheric windows especially at temperature conditions relevant for our atmosphere. In addition, as a result of the difficulty to measure weak broadband absorption signals, the few available measurements show large disagreements. We report here accurate measurements of the water vapor self-continuum absorption in the 2.1 μm window by Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) for two spectral points located at the low energy edge and at the center of the 2.1 μm transparency window, at 4302 and 4723 cm−1, respectively. Self-continuum cross sections, CS, were retrieved with a few % relative uncertainty, from the quadratic dependence of the spectrum base line level measured as a function of water vapor pressure, between 0 and 16 Torr. At 296 K, the CS value at 4302 cm−1 is found 40% higher than predicted by the MT_CKD V2.5 model, while at 4723 cm−1, our value is 5 times larger than the MT_CKD value. On the other hand, these OF-CEAS CS values are significantly smaller than recent measurements by Fourier transform spectroscopy at room temperature. The temperature dependence of the self-continuum cross sections was also investigated for temperatures between 296 K and 323 K (23-50 °C). The derived temperature variation is found to be similar to that derived from previous Fourier transform spectrometer (FTS) measurements performed at higher temperatures, between 350 K and 472 K. The whole set of measurements spanning the 296-472 K temperature range follows a simple exponential law in 1/T with a slope close to the dissociation energy of the water dimer, D0 ≈ 1100 cm−1.
Resonant tunneling diodes as energy-selective contacts used in hot-carrier solar cells
Authors: Takeda Yasuhiko , Ichiki Akihisa , Kusano Yuya , Sugimoto Noriaki , Motohiro Tomoyoshi
Published: October 2015

Among the four features unique to hot-carrier solar cells (HC-SCs): (i) carrier thermalization time and (ii) carrier equilibration time in the absorber, (iii) energy-selection width and (iv) conductance of the energy-selective contacts (ESCs), requisites of (i)-(iii) for high conversion efficiency have been clarified. We have tackled the remaining issues related to (iv) in the present study. The detailed balance model of HC-SC operation has been improved to involve a finite value of the ESC conductance to find the required values, which in turn has been revealed to be feasible using resonant tunneling diodes (RTDs) consisting of semiconductor quantum dots (QDs) and quantum wells (QWs) by means of a formulation to calculate the conductance of the QD- and QW-RTDs derived using the rigorous solutions of the effective-mass Hamiltonians. Thus, all of the four requisites unique to HC-SCs to achieve high conversion efficiency have been elucidated, and the two requisites related to the ESCs can be fulfilled using the QD- and QW-RTDs.
Radiation hardening in sol-gel derived Er3+-doped silica glasses
Authors: Hari Babu B. , Ollier Nadège , León Pichel Mónica , El Hamzaoui Hicham , Poumellec Bertrand , Bigot Laurent , Savelii Inna , Bouazaoui Mohamed , Ibarra Angel , Lancry Matthieu
Published: October 2015

The aim of the present paper is to report the effect of radiation on the Er3+-doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er3+-doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′δ point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposure to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er3+ to Er2+ ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects.
Controlling the directionality of spontaneous emission by evanescent wave coupling
Authors: Wang Xue-Lun , Hao Guo-Dong , Toda Naoya
Published: October 2015

We report an approach toward controlling the directionality of spontaneous emissions by employing the evanescent wave coupling effect in a subwavelength-sized ridge or truncated cone structure. An InGaAs/GaAs light-emitting diode in which a stripe-shaped InGaAs/GaAs quantum well with a stripe width of about 100 nm is embedded at the center of a subwavelength-sized GaAs ridge (of width ∼520 nm) is fabricated by micro processing and epitaxial regrowth techniques. Strong directionalities characterized by a half-intensity angle of 43° are observed in planes perpendicular to the ridge axis. The directionality is found to be almost independent of operating conditions.
Enhancement of humidity sensitivity of graphene through functionalization with polyethylenimine
Authors: Ben Aziza Zeineb , Zhang Kang , Baillargeat Dominique , Zhang Qing
Published: October 2015

In this work, we show that the sensing performance of graphene based humidity sensors can be largely improved through polymer functionalization. Chemical vapor deposited graphene is functionalized with amine rich polymer, leading to electron transfer from amine groups in the polymer to graphene. The functionalized graphene humidity sensor has demonstrated good sensitivity, recovery, and repeatability. Charge transfer between the functionalized graphene and water molecules and the sensing mechanism are studied systemically using field effect transistor geometry and scanning Kelvin probe microscopy.
Near bandgap second-order nonlinear optical characteristics of MoS2 monolayer transferred on transparent substrates
Authors: Clark D. J. , Le C. T. , Senthilkumar V. , Ullah F. , Cho H.-Y. , Sim Y. , Seong M.-J. , Chung K.-H. , Kim Y. S. , Jang J. I.
Published: October 2015

We have investigated the second-order nonlinear optical (NLO) properties of CVD-grown MoS2 monolayer (ML) transferred onto transparent substrates such as fused silica and polyethylene terephthalate. The physical properties of the transferred MLs were characterized by optical and NLO methods. We measured the second-order susceptibility χ(2) in the spectral range of λ= 1064–1600 nm in which the corresponding second harmonic radiation resonates with the exciton levels. It was found that χ(2) is strongly enhanced by up to a factor of 5 near the A- and B-exciton levels due to two-photon resonance. The absolute χ(2) values of our samples determined by both reflection and transmission geometry are on par with that of as-grown MLs. Our results imply that the cavity-confinement scheme can be employed for maximizing the nonlinear optical efficiency of atomically thin transition metal dichalcogenides for transparent/flexible optoelectronics applications, especially when oriented stacking of transferred MLs are controllable.
Note: Small anaerobic chamber for optical spectroscopy
Authors: Chauvet Adrien A. P. , Agarwal Rachna , Cramer William A. , Chergui Majed
Published: October 2015

The study of oxygen-sensitive biological samples requires an effective control of the atmosphere in which they are housed. In this aim however, no commercial anaerobic chamber is adequate to solely enclose the sample and small enough to fit in a compact spectroscopic system with which analysis can be performed. Furthermore, spectroscopic analysis requires the probe beam to pass through the whole chamber, introducing a requirement for adequate windows. In response to these challenges, we present a 1 l anaerobic chamber that is suitable for broad-band spectroscopic analysis. This chamber has the advantage of (1) providing access, via a septum, to the sample and (2) allows the sample position to be adjusted while keeping the chamber fixed and hermetic during the experiment.
Magnetic epoxy nanocomposites with superparamagnetic MnFe2O4 nanoparticles
Authors: Huang Jiangnan , Cao Yonghai , Zhang Xi , Li Yutong , Guo Jiang , Wei Suying , Peng Xiangfang , Shen Tong D. , Guo Zhanhu
Published: October 2015

Manganese iron oxide (MnFe2O4) nanoparticles successfully served as nanofillers for obtaining magnetic epoxy nanocomposites. The viscosities of MnFe2O4/epoxy resin liquid suspensions increased with increasing the nanoparticles loading except the suspension with 5.0 and 1.0 wt% loading, whose viscosities were lower than that of pure epoxy. The introduction of MnFe2O4 nanoparticles showed a lower onset decomposition temperature and glass transition temperature (Tg), which decreased with increasing the nanoparticles loading. The storage modulus and tensile strength of 1.0 wt% MnFe2O4/epoxy were a little higher than that of pure epoxy. The coercivity of MnFe2O4/epoxy nanocomposites with 5.0 wt% (44.7 Oe) and 10.0 wt% (43.9 Oe) displayed much higher than that of pure MnFe2O4 nanoparticles (14.94 Oe). The magnetic moment (m) of nanocomposites (1.354 μB for 10 wt% MnFe2O4/epoxy) are higher than that of pure MnFe2O4 nanoparticles (1.244 μB). The increased real permittivity observed in the nanocomposites was attributed to the interfacial polarization. The intrinsic permittivity of the MnFe2O4 nanoparticles was also calculated.
Neutron stars’ hidden nuclear pasta
Authors: Rea Nanda
Published: October 2015

The novel, amorphous state of matter that exists in the crust of neutron stars leaves a trace in the spins of magnetized, rapidly rotating pulsars.
Multimodal constructions in children
Authors: Andrén Mats
Published: October 2015

Swedish children’s use of the headshake from 18 to 30 months shows a developmental progression from rote-learned and formulaic coordination with speech to increasingly more flexible and productive coordination with speech. To deal with these observations, I make use of the concept ofmultimodal constructions, to extend usage-based approaches to language learning and construction grammar by inclusion of the kinetic domain. These ideas have consequences for the (meta‑)theoretical question of whether gesture can be said to be part of language or not. I suggest thatsomespeech-coordinated gestures, including the headshake, can be considered part of language, also in the traditional sense of language as a conventionalized system.
A convergence to Brownian motion on sub-Riemannian manifolds
Authors: Gordina Maria , Laetsch Thomas
Published: October 2015

This paper considers a classical question of approximation of Brownian motion by a random walk in the setting of a sub-Riemannian manifold

M
M

. To construct such a random walk we first address several issues related to the degeneracy of such a manifold. In particular, we define a family of sub-Laplacian operators naturally connected to the geometry of the underlying manifold. In the case when

M
M

is a Riemannian (non-degenerate) manifold, we recover the Laplace-Beltrami operator. We then construct the corresponding random walk, and under standard assumptions on the sub-Laplacian and

M
M

we show that this random walk converges (at the level of semigroups) to a process, horizontal Brownian motion, whose infinitesimal generator is the sub-Laplacian. An example of the Heisenberg group equipped with a standard sub-Riemannian metric is considered in detail, in which case the sub-Laplacian we introduced is shown to be the sum of squares (Hörmander’s) operator.
Dual pulse-chase microscopy reveals early divergence in the biosynthetic trafficking of the Na,K-ATPase and E-cadherin
Authors: Farr Glen A. , Hull Michael , Stoops Emily H. , Bateson Rosalie , Caplan Michael J.
Published: October 2015

Recent evidence indicates that newly synthesized membrane proteins that share the same distributions in the plasma membranes of polarized epithelial cells can pursue a variety of distinct trafficking routes as they travel from the Golgi complex to their common destination at the cell surface. In most polarized epithelial cells, both the Na,K-ATPase and E-cadherin are localized to the basolateral domains of the plasma membrane. To examine the itineraries pursued by newly synthesized Na,K-ATPase and E-cadherin in polarized MDCK epithelial cells, we used the SNAP and CLIP labeling systems to fluorescently tag temporally defined cohorts of these proteins and observe their behaviors simultaneously as they traverse the secretory pathway. These experiments reveal that E-cadherin is delivered to the cell surface substantially faster than is the Na,K-ATPase. Furthermore, the surface delivery of newly synthesized E-cadherin to the plasma membrane was not prevented by the 19°C temperature block that inhibits the trafficking of most proteins, including the Na,K-ATPase, out of the trans-Golgi network. Consistent with these distinct behaviors, populations of newly synthesized E-cadherin and Na,K-ATPase become separated from one another within the trans-Golgi network, suggesting that they are sorted into different carrier vesicles that mediate their post-Golgi trafficking.
Basic mechanism for biorientation of mitotic chromosomes is provided by the kinetochore geometry and indiscriminate turnover of kinetochore microtubules
Authors: Zaytsev Anatoly V. , Grishchuk Ekaterina L.
Published: October 2015

Accuracy of chromosome segregation relies on the ill-understood ability of mitotic kinetochores to biorient, whereupon each sister kinetochore forms microtubule (MT) attachments to only one spindle pole. Because initial MT attachments result from chance encounters with the kinetochores, biorientation must rely on specific mechanisms to avoid and resolve improper attachments. Here we use mathematical modeling to critically analyze the error-correction potential of a simplified biorientation mechanism, which involves the back-to-back arrangement of sister kinetochores and the marked instability of kinetochore–MT attachments. We show that a typical mammalian kinetochore operates in a near-optimal regime, in which the back-to-back kinetochore geometry and the indiscriminate kinetochore–MT turnover provide strong error-correction activity. In human cells, this mechanism alone can potentially enable normal segregation of 45 out of 46 chromosomes during one mitotic division, corresponding to a mis-segregation rate in the range of 10−1–10−2per chromosome. This theoretical upper limit for chromosome segregation accuracy predicted with the basic mechanism is close to the mis-segregation rate in some cancer cells; however, it cannot explain the relatively low chromosome loss in diploid human cells, consistent with their reliance on additional mechanisms.
missMethyl: an R package for analyzing data from Illumina’s HumanMethylation450 platform
Authors: Phipson Belinda , Maksimovic Jovana , Oshlack Alicia
Published: October 2015

Summary: DNA methylation is one of the most commonly studied epigenetic modifications due to its role in both disease and development. The Illumina HumanMethylation450 BeadChip is a cost-effective way to profile >450 000 CpGs across the human genome, making it a popular platform for profiling DNA methylation. Here we introduce missMethyl, an R package with a suite of tools for performing normalization, removal of unwanted variation in differential methylation analysis, differential variability testing and gene set analysis for the 450K array.

Availability and implementation: missMethyl is an R package available from the Bioconductor project at www.bioconductor.org.

Contact:  alicia.oshlack@mcri.edu.au

Supplementary information:  Supplementary data are available at Bioinformatics online.
regioneR: an R/Bioconductor package for the association analysis of genomic regions based on permutation tests
Authors: Gel Bernat , Díez-Villanueva Anna , Serra Eduard , Buschbeck Marcus , Peinado Miguel A. , Malinverni Roberto
Published: October 2015

Motivation: Statistically assessing the relation between a set of genomic regions and other genomic features is a common challenging task in genomic and epigenomic analyses. Randomization based approaches implicitly take into account the complexity of the genome without the need of assuming an underlying statistical model.

Summary: regioneR is an R package that implements a permutation test framework specifically designed to work with genomic regions. In addition to the predefined randomization and evaluation strategies, regioneR is fully customizable allowing the use of custom strategies to adapt it to specific questions. Finally, it also implements a novel function to evaluate the local specificity of the detected association.

Availability and implementation: regioneR is an R package released under Artistic-2.0 License. The source code and documents are freely available through Bioconductor (http://www.bioconductor.org/packages/regioneR).

Contact:  rmalinverni@carrerasresearch.org
Response Assessment in Neuro-Oncology (RANO): more than imaging criteria for malignant glioma
Authors: Chang Susan M. , Wen Patrick Y. , Vogelbaum Michael A. , Macdonald David R. , van den Bent Martin J.
Published: October 2015

The introduction of antiangiogenic therapies for the treatment of malignant glioma and the effect of these agents on standard imaging studies were the stimuli for forming a small group of investigators to critically evaluate the limitations of the Macdonald criteria in assessing response to treatment. The initial goal of this group was to highlight the challenges in accurately determining the efficacy of therapeutic interventions for malignant glioma and to develop new criteria that could be implemented in clinical care as well as in the design and conduct of clinical trials. This initial Response Assessment in Neuro-Oncology (RANO) effort started in 2008 and over the last 7 years, it has expanded to include a critical review of response assessment across several tumor types as well as endpoint selection and trial design to improve outcome criteria for neuro-oncological trials. In this paper, we review the overarching principles of the RANO initiative and the efforts to date. We also highlight the diverse and expanding efforts of the multidisciplinary groups of investigators who have volunteered their time as part of this endeavor.
Malignancies, Particularly B-Cell Lymphomas, Are a Frequent Cause of Mortality in Human Immunodeficiency Virus-1 Patients Despite Highly Active Antiretroviral Therapy
Authors: Griffin Daniel O. , Metzger Michael , Poeth Kaitlin , Deng Kathy , Dharsee Arif , Rico Juan Carlos , McGowan Joseph
Published: October 2015

Human immunodeficiency virus (HIV)-1-infected individuals are affected by diseases at rates above those of their HIV-negative peers despite the increased life expectancy of the highly active antiretroviral therapy era. We followed a cohort of approximately 2000 HIV-1-infected patients for 5 years. The most frequent cause of death in this HIV-1-infected cohort was malignancy, with 39% of all classified deaths due to cancer. Among the cancer deaths, B-cell lymphomas were the most commonly seen malignancy, representing 34% of all cancer deaths. These lymphomas were very aggressive with a median survival of <2 months from time of diagnosis.
Trends in Orbital Decompression Techniques of Surveyed American Society of Ophthalmic Plastic and Reconstructive Surgery Members
Authors: Reich Shani S. , Null Robert C. , Timoney Peter J. , Sokol Jason A.
Published: October 2015

Purpose:

To assess current members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) regarding preference in surgical techniques for orbital decompression in Graves’ disease.

Methods:

A 10-question web-based, anonymous survey was distributed to oculoplastic surgeons utilizing the ASOPRS listserv. The questions addressed the number of years of experience performing orbital decompression surgery, preferred surgical techniques, and whether orbital decompression was performed in collaboration with an ENT surgeon.

Results:

Ninety ASOPRS members participated in the study. Most that completed the survey have performed orbital decompression surgery for >15 years. The majority of responders preferred a combined approach of floor and medial wall decompression or balanced lateral and medial wall decompression; only a minority selected a technique limited to 1 wall. Those surgeons who perform fat decompression were more likely to operate in collaboration with ENT. Most surgeons rarely remove the orbital strut, citing risk of worsening diplopia or orbital dystopia except in cases of optic nerve compression or severe proptosis. The most common reason given for performing orbital decompression was exposure keratopathy. The majority of surgeons perform the surgery without ENT involvement, and number of years of experience did not correlate significantly with collaboration with ENT.

Conclusions:

The majority of surveyed ASOPRS surgeons prefer a combined wall approach over single wall approach to initial orbital decompression. Despite the technological advances made in the field of modern endoscopic surgery, no single approach has been adopted by the ASOPRS community as the gold standard.
Ultrasound-Assisted Lumbar Puncture in Pediatric Emergency Department
Authors: Özdamar Emre , Özkaya Ahmet Kağan , Güler Ekrem , Cantay Burcu , Karabel Nihal , Göksügür Yalçin , Çetinkaya Ahmet , Emre Özcan
Published: October 2015

Background

Lumbar puncture (LP) is one of the essential diagnostic tools in pediatric emergency services. Recently, ultrasound-assisted LP was reported to be beneficial in the emergency service by facilitating the procedure and improving the successful procedure rates. In addition, this method may be effective in reducing patient and parent anxiety due to the LP procedure.

Objectives

The aim of this study was to investigate the effect of ultrasound-assisted LP on the outcomes of puncture procedures and traumatic LP.

Methods

The study included patients younger than 18 years, who were admitted to the pediatric emergency service and underwent LP because of suspected central nervous system infection. The patients requiring LP were randomly divided into 2 groups designated as odd and even. One group received LP using the conventional method, whereas the other group had LP after spinal space measurement by ultrasound. The patients who did and who did not undergo ultrasound-assisted LP were compared for demographics, number of puncture attempts, and traumatic LP. Statistical analysis was performed using the Mann-Whitney U test and the Student t test. The χ2 test was used when nominal data were compared between the 2 groups.

Results

Ultrasound-assisted LP was performed in 56 patients, and LP by using conventional method was performed in 55 patients. There was traumatic LP in 5 (8.9%) of the patients who underwent ultrasound-assisted LP and 9 (16.3%) of the patients who underwent LP using the conventional method (P > 0.05). The number of puncture attempts was 2 or more in 2 (3.5%) of the patients who underwent ultrasound-assisted LP and 5 (9%) of the patients who had LP using the conventional method (P > 0.05).

Conclusions

Ultrasound-assisted LP reduced traumatic LP and the number of puncture attempts in pediatric patients; however, the results were not statistically significant.
Understanding biases in ribosome profiling experiments reveals signatures of translation dynamics in yeast
Authors: Hussmann Jeffrey A. , Patchett Stephanie , Johnson Arlen , Sawyer Sara , Press William H.
Published: October 2015

Ribosome profiling produces snapshots of the locations of actively translating ribosomes on messenger RNAs. These snapshots can be used to make inferences about translation dynamics. Recent ribosome profiling studies in yeast, however, have reached contradictory conclusions regarding the average translation rate of each codon. Some experiments have used cycloheximide (CHX) to stabilize ribosomes before measuring their positions, and these studies all counterintuitively report a weak negative correlation between the translation rate of a codon and the abundance of its cognate tRNA. In contrast, some experiments performed without CHX report strong positive correlations. To explain this contradiction, we identify unexpected patterns in ribosome density downstream of each type of codon in experiments that use CHX. These patterns are evidence that elongation continues to occur in the presence of CHX but with dramatically altered codon-specific elongation rates. The measured positions of ribosomes in these experiments therefore do not reflect the amounts of time ribosomes spend at each position in vivo. These results suggest that conclusions from experiments in yeast using CHX may need reexamination. In particular, we show that in all such experiments, codons decoded by less abundant tRNAs were in fact being translated more slowly before the addition of CHX disrupted these dynamics.
Enabling functional genomics with genome engineering
Authors: Hilton Isaac B. , Gersbach Charles A.
Published: October 2015

Advances in genome engineering technologies have made the precise control over genome sequence and regulation possible across a variety of disciplines. These tools can expand our understanding of fundamental biological processes and create new opportunities for therapeutic designs. The rapid evolution of these methods has also catalyzed a new era of genomics that includes multiple approaches to functionally characterize and manipulate the regulation of genomic information. Here, we review the recent advances of the most widely adopted genome engineering platforms and their application to functional genomics. This includes engineered zinc finger proteins, TALEs/TALENs, and the CRISPR/Cas9 system as nucleases for genome editing, transcription factors for epigenome editing, and other emerging applications. We also present current and potential future applications of these tools, as well as their current limitations and areas for future advances.
Induction of Liver Tumors in Mice with N-Ethyl-N-Nitrosourea or N-Nitrosodiethylamine
Authors: Gurley Kay E. , Moser Russell D. , Kemp Christopher J.
Published: October 2015

Since the groundbreaking studies in the middle part of the last century showing liver cancer in rodents exposed to aromatic amines, the liver has been widely used as a model target organ of chemical carcinogenesis. This protocol describes a method for inducing liver tumors by injecting mice with the widely used alkylating agents N-ethyl-N-nitrosourea (ENU) and N-nitrosodiethylamine (DEN). ENU does not require metabolic activation and readily induces tumors in a number of tissues, including the lungs, stomach, and ovaries, as well as inducing lymphomas. Mice injected with DEN can also develop other tumors, including those of the gastrointestinal tract, skin, lungs, and lymphocytes, but because DEN is metabolized in the liver, it is most effective at inducing liver tumors.
A Method to Monitor Lysosomal Membrane Permeabilization by Immunocytochemistry
Authors: Groth-Pedersen Line , Jäättelä Marja , Nylandsted Jesper
Published: October 2015

Programmed cell death involving lysosomal membrane permeabilization (LMP) is a common phenomenon—more the rule than the exception under various cytotoxic stimuli and stressful cellular conditions. The protocol presented here is based on immunocytochemical staining of cathepsin B or L to visualize translocation from the lysosomal lumen to the cytosol. In healthy cells, cathepsins appear in localized punctate structures representing intact lysosomes, whereas LMP results in a diffuse staining pattern throughout the cytoplasm. LMP can be triggered upstream, downstream, or independently of the classical apoptotic death pathway involving mitochondrial outer membrane permeabilization (MOMP). Co-staining with antibodies recognizing the active form of Bax allows investigation of the order of events between LMP and MOMP in death signaling.
Purification and Injection of Retroviral Vectors
Authors: Tashiro Ayumu , Zhao Chunmei , Suh Hoonkyo , Gage Fred H.
Published: October 2015

Retroviral vectors are powerful tools for genetic manipulation. This protocol discusses the production, purification, and use of replication-deficient retroviral vectors based on Moloney murine leukemia virus and lentivirus. It also describes the injection of a retroviral vector into the dentate gyrus of young adult mice to fluorescently label live murine brain tissue.
Preparation and Use of Retroviral Vectors for Labeling, Imaging, and Genetically Manipulating Cells
Authors: Tashiro Ayumu , Zhao Chunmei , Suh Hoonkyo , Gage Fred H.
Published: October 2015

Retroviral vectors are a powerful technology for achieving long-term genetic manipulation. This introduction provides some background on replication-deficient retroviral vectors based on Moloney murine leukemia virus and lentivirus. Details, examples, and associated protocols are provided for using these vectors to fluorescently label, genetically alter, and image both live and fixed murine brain tissue.
Crystalline state photochromism of 3-furylfulgides: impact of size and bond flexibility of the non-aromatic alkylidene group
Authors: Hettiarachchi Champika V. , Weerasekara Roshan K. , Uekusa Hidehiro
Published: October 2015

3-Furylfulgides are photochromic compounds showing high thermal stability in their closed forms. However, their photochromic properties in the solid state should be improved further to fabricate molecular devices. Understanding how the size and the flexibility of the non-aromatic alkylidene moiety alter the crystalline state photochromic properties is also important here, as the alkylidene group is directly involved in the photochromic ring closing and opening reactions. The synthesis of four 3-furylfulgides composed of different alkylidene groups (rigid isopropyl, flexible 2-butyl, rigid cyclopentyl and flexible cyclohexyl), their crystal structures and structure–photochromic property correlation in the crystalline state are reported here. Crystallographic data along with reaction cavity volumes calculated using the programCAVITY[Ohashiet al.(1981),J. Am. Chem. Soc.103, 5805–5812] disclosed that fulgides with flexible groups at the ring closing site have more free volume around the reactive area in the crystal lattice, which can provide more space for the atomic movements in the reaction and flexibility can reduce the strain built up in the closedC-isomers by making conformations. According to UV–vis spectroscopic data, a higher yield ofC-isomers and a better fatigue resistance were obtained for the 3-furylfulgide with the largest and flexible cyclohexyl group showing greater photochromic properties in the crystalline state than the fulgide containing the smallest and rigid isopropyl group.
At last! The single-crystal X-ray structure of a naturally occurring sample of the ilmenite-type oxide FeCrO3
Authors: Pérez-Cruz María Ana , Elizalde-González María de la Paz , Escudero Roberto , Bernès Sylvain , Silva-González Rutilo , Reyes-Ortega Yasmi
Published: October 2015

A natural single crystal of the ferrimagnetic oxide FeCrO3, which was found in an opencast mine situated in the San Luis Potosí State in Mexico, has been characterized in order to elucidate some outstanding issues about the actual structure of this material. The single-crystal X-ray analysis unambiguously shows that transition metal cations are segregated in alternating layers normal to the threefold crystallographic axis, affording a structure isomorphous to that of ilmenite (FeTiO3), in the space group R \overline{3}. The possible occurrence of cation antisite and vacancy defects is below the limit of detection available from X-ray data. Structural and magnetic results are in agreement with the coherent slow intergrowth of magnetic phases provided by the two antiferromagnetic corundum-type parent oxides Fe2O3(hematite) and Cr2O3(eskolaite). Our results are consistent with the most recent density functional theory (DFT) studies carried out on digital FeCrO3[Sadat Nabi & Pentcheva (2011).Phys. Rev. B,83, 214424], and suggest that synthetic samples of FeCrO3might present a cation distribution different to that of the ilmenite structural type.
Voluntary reporting of intellectual capital
Authors: Low Mary , Samkin Grant , Li Yuanyuan
Published: October 2015

Purpose

– The purpose of this paper is to examine the quality of voluntary intellectual capital (IC) by universities in New Zealand, Australia, and the UK.

Design/methodology/approach

– An IC framework was developed to measure IC reporting in the university sector. Content analysis was used to analyse the 2011 annual reports before a three-year comparative analysis of 90 universities (eight New Zealand universities, 38 Australian universities, and 44 UK universities) was undertaken.

Findings

– New Zealand and Australian universities outperformed the UK universities in terms of IC disclosures. Additionally, the study found moderate increases in the levels of IC disclosures over the period of the study. The quality of IC disclosures by New Zealand universities was generally higher than their Australian and UK counterparts. Internal capital and human capital were the most disclosed categories with external capital being the least frequently disclosed in all three countries. However, the quality of external capital disclosures was higher than internal and human capital. Finally, most IC disclosures were narrative in nature.

Practical implications

– The framework developed in this study could be adapted, further enhanced, and then applied to exploring IC disclosures in higher educational institutes in other jurisdictions.

Originality/value

– This is the first comparative analysis of IC disclosures made by universities in three countries.
Intangible-intensive profile of a company: the key to outperforming
Authors: Shakina Elena , Barajas Angel
Published: October 2015

Purpose

– The purpose of this paper is to reveal and empirically validate a new typology of company strategic profiles regarding intangible resources.

Design/methodology/approach

– The study is carried out in three steps. The first stage comes to identify the coordinates of intangibles in which strategic profiles are found. The second stage enables a clusterization of more than 1,600 European companies observed during seven years in the coordinates of intangibles. The last step introduces comparative analysis of these clusters in terms of their performance.

Findings

– As a result of empirical analysis three strategic profiles regarding intangibles are discovered. Two of these profiles are called intangible-intensive as they demonstrate clear predominance of a particular set of intangibles. The innovative profile is associated with intensive investment in innovation and networking capabilities. The conservative profile puts emphasis on managerial capabilities and development of business process. The non-intangible-intensive profile, that has been called moderate, evenly allocates resources among intangibles keeping them on a low level relative to the intangible-intensive profiles.

Practical implications

– This research is useful for practitioners in strategic and knowledge management. It provides insight into common features of company strategies for intangibles as well their impact on short- and long-term performance.

Originality/value

– This work contributes to the field of strategic knowledge management by demonstrating a new relevant typology in company behavior regarding intangibles. Moreover, it equips decision makers in companies with a tool to design strategic vision in intangibles.
Hydro‐frac monitoring using ground time‐domain electromagnetics
Authors: Hoversten G. Michael , Commer Michael , Haber Eldad , Schwarzbach Christoph
Published: October 2015

As motivation for considering new electromagnetic techniques for hydraulic fracture monitoring, we develop a simple financial model for the net present value offered by geophysical characterization to reduce the error in stimulated reservoir volume calculations. This model shows that even a 5% improvement in stimulated reservoir volume for a 1 billion barrel (bbl.) field results in over 1 billion U.S. dollars (US$) in net present value over 24 years for US$100/bbl. oil and US$0.5 billion for US$50/bbl. oil. The application of conductivity upscaling, often used in electromagnetic modeling to reduce mesh size and thus simulation runtimes, is shown to be inaccurate for the high electrical contrasts needed to represent steel‐cased wells in the earth. Fine‐scale finite‐difference modeling with 12.22‐mm cells to capture the steel casing and fractures shows that the steel casing provides a direct current pathway to a created fracture that significantly enhances the response compared with neglecting the steel casing. We consider conductively enhanced proppant, such as coke‐breeze‐coated sand, and a highly saline brine solution to produce electrically conductive fractures. For a relatively small frac job at a depth of 3 km, involving 5,000 bbl. of slurry and a source midpoint to receiver separation of 50 m, the models show that the conductively enhanced proppant produces a 15% increase in the electric field strength (in‐line with the transmitter) in a 10‐Ωm background. In a 100‐Ωm background, the response due to the proppant increases to 213%. Replacing the conductive proppant by brine with a concentration of 100,000‐ppm NaCl, the field strength is increased by 23% in the 100‐Ωm background and by 2.3% in the 10‐Ωm background. All but the 100,000‐ppm NaCl brine in a 10‐Ωm background produce calculated fracture‐induced electric field increases that are significantly above 2%, a value that has been demonstrated to be observable in field measurements.
Optimal implicit staggered‐grid finite‐difference schemes based on the sampling approximation method for seismic modelling
Authors: Yang Lei , Yan Hongyong , Liu Hong
Published: October 2015

We propose new implicit staggered‐grid finite‐difference schemes with optimal coefficients based on the sampling approximation method to improve the numerical solution accuracy for seismic modelling. We first derive the optimized implicit staggered‐grid finite‐difference coefficients of arbitrary even‐order accuracy for the first‐order spatial derivatives using the plane‐wave theory and the direct sampling approximation method. Then, the implicit staggered‐grid finite‐difference coefficients based on sampling approximation, which can widen the range of wavenumber with great accuracy, are used to solve the first‐order spatial derivatives. By comparing the numerical dispersion of the implicit staggered‐grid finite‐difference schemes based on sampling approximation, Taylor series expansion, and least squares, we find that the optimal implicit staggered‐grid finite‐difference scheme based on sampling approximation achieves greater precision than that based on Taylor series expansion over a wider range of wavenumbers, although it has similar accuracy to that based on least squares. Finally, we apply the implicit staggered‐grid finite difference based on sampling approximation to numerical modelling. The modelling results demonstrate that the new optimal method can efficiently suppress numerical dispersion and lead to greater accuracy compared with the implicit staggered‐grid finite difference based on Taylor series expansion. In addition, the results also indicate the computational cost of the implicit staggered‐grid finite difference based on sampling approximation is almost the same as the implicit staggered‐grid finite difference based on Taylor series expansion.