bluuebunny/crossref_metadata_2025 huggingface dataset:
Assigning exposure duration to single prescriptions by use of the waiting time distribution
Authors: Pottegård Anton , Hallas Jesper
Published: May 2013

Purpose

The purpose of this study is to develop and present a method to calculate which exposure duration should be assigned to single prescriptions for use in databases where information on expected duration is not recorded.

Methods

We propose a method, based on the waiting time distribution (WTD), which estimates how frequently prevalent users redeem new prescriptions. However, we added two steps to the WTD‐approach. First, we excluded incident users, representing noise in the analysis. Second, we calculated the cumulative percentage of users that had presented themselves after a given number of days. Using a cutoff value of 80%, we thus calculated the number of days for the majority of prevalent users to present themselves, that is, the exposure duration that should be assigned to the single prescription. The primary strength of the method is that it can be applied in a standardized fashion and that it does not require information on dosage instructions. The primary weakness of the method is that it is only usable on drugs with predominantly chronic use patterns. The method was tested using four model drugs: bendroflumethiazide, warfarin, levothyroxine, and non‐steroidal anti‐inflammatory drugs (NSAIDs).

Results

We found exposure period estimates of 92, 86, 69, and 210 days for bendroflumethiazide, levothyroxine, warfarin, and NSAIDs prescriptions, respectively. NSAIDs were found not to comply with the requirements of the method. The calculated number of exposed days was only slightly influenced by the assumptions of the method.

Conclusions

The method provides a useful approach to generate automated estimates of exposure duration that should be assigned to each prescription. Copyright © 2013 John Wiley & Sons, Ltd.
Scanning Kelvin probe study of photolabile silane surface modification of indium tin oxide
Authors: Chak Elaine Yee Ling , Pawlowska Natalia Maria , Blaszykowski Christophe , Thompson Michael
Published: May 2013

The scanning Kelvin nanoprobe (SKN) is an exquisitely sensitive device capable of detecting subtle changes in work function associated with alteration of surface chemistry and interfacial dipole. This instrument is highly versatile and has notably been recently used for (i) the investigation of biological interactions occurring at the interface of multiplexed microarrayed platforms and (ii) the characterization of high work function materials for application in molecular optoelectronics. Herein, we further implement the SKN to characterize, along with angle‐resolved X‐ray photoelectron spectroscopy and contact angle goniometry, the surface modification of indium tin oxide substrates with photopatternable silane adlayers. These molecular films are constructed in a straightforward and economical manner from alkyltrichlorosilane surface‐modifying molecules that possess a distal, UV‐photolabile o‐nitrobenzyl moiety. Employing a photomask, we were able to selectively pattern regions of the photoreactive silane adlayer and confirm the corresponding changes in surface potential through contact potential difference measurements. Copyright © 2013 John Wiley & Sons, Ltd.
Shrinkage estimation and the use of additional information when calibrating in the presence of random effects
Authors: Oman Samuel D.
Published: May 2013

Letxdenote a precise measurement of a quantity andYan inexact measurement, which is, however, less expensive or more easily obtained thanx. We have available a calibration set comprising clustered sets of (x,Y) observations, obtained from different sampling units. At the prediction step, we will only observeYfor a new unit, and we wish to estimate the corresponding unknownx, which we denote byξ. This problem has been treated under the assumption thatxandYare linearly related. Here, we expand on those results in three directions: First, we show that if we centerξabout a known valuec, for example, the meanx‐value of the calibration set, then the proposed estimator now shrinks toc. Second, we examine in detail the performance of the estimator, which was proposed when one or more (x,Y) observations can be obtained for the new subject. Third, we compare the Fieller‐like confidence intervals, previously proposed, witht‐like intervals based on asymptotic moments of the point estimate. We illustrate and evaluate our procedures in the context of a data set of true bladder‐volumes (x) and ultrasound measurements (Y). Copyright © 2013 John Wiley & Sons, Ltd.
Method for Deriving Functional Architectures from Use Cases
Authors: Lamm Jesko G. , Weilkiens Tim
Published: May 2013

Functional architecture enables the description of systems independent of their technology. A method for obtaining functional architectures for systems (the FAS method) is introduced. It provides a well‐defined procedure for deriving functional architecture from use cases by using heuristics for grouping functions and allocating them to functional blocks. A specialty of the FAS method is the structural representation of functional architectures in block‐oriented form. An example system from the hearing instrument domain is used for demonstrating the method. The application of the FAS method together with the SysML modeling language is described, and modeling tool support is discussed. The authors report their experiences with the method from industrial projects, for example that analysts and architects could improve their communication by means of the FAS method. It is concluded that the method together with tool support facilitates the team process of creating model‐based functional architectures based on use cases.
Credibility Assessment of Models and Simulations Based on NASA’s Models and Simulation Standard Using the Delphi Method
Authors: Ahn Jaemyung , de Weck Olivier L. , Steele Martin
Published: May 2013

This paper introduces a procedure to assess the credibility of models and simulations (M&S) as a group activity based on NASA’s new standard for M&S NASA‐STD‐7009. The Delphi method, which is characterized by iterative surveys with controlled feedback, was selected to implement the assessment. The proposed procedure is expected to address the issues in the M&S assessment related to a high level of required expertise and group decision making. An actual credibility assessment study using the proposed procedure on an M&S platform referred to as SpaceNet has been carried out by ten panel members through a two‐round Delphi. The study concluded that the overall credibility of SpaceNet version 1.3 was between the development level and production level. The variances of the assessments in the second‐round survey were significantly reduced compared with the first‐round results, which indicates the effectiveness of the proposed procedure.
Management of erectile dysfunction in men treated with androgen deprivation therapy
Authors: Wilson James M. , Atkinson Charlotte , Hughes Simon
Published: May 2013

In this series, the authors present cases of men being treated with androgen deprivation therapy, and highlight their management to prevent and treat associated toxicities. This second article will consider the management of erectile dysfunction. Copyright © 2013 John Wiley & Sons
Real‐time elastography for assessment of uterine disorders
Authors: Stoelinga B. , Hehenkamp W. J. K. , Brölmann H. A. M. , Huirne J. A. F.
Published: May 2013

Objectives

Sonoelastography is an ultrasound‐imaging technique that measures tissue strain. The aim of this study was to define, in a systematic manner, specific sonoelastographic characteristics of the myometrium, fibroids and adenomyosis, to evaluate the feasibility of sonoelastography in patients with suspected gynecological pathology and to compare the results with histology and/or magnetic resonance imaging (MRI)‐based diagnoses.

Methods

We performed a prospective observational cohort study between 2009 and 2011. Two‐hundred and eighteen women with suspected gynecological pathology underwent routine transvaginal ultrasound and additional real‐time sonographic elastography. Sixty‐nine of the 218 women underwent MRI and/or histological examination and were included in the final analysis. Acquisition of elastographic images was standardized. We analyzed the elastographic characteristics of myometrium, fibroids and adenomyosis. An independent observer, unaware of clinical, histological or MRI findings, evaluated the recorded elastographic images and cineloops. These elastographic‐based diagnoses were compared with histology and/or MRI diagnoses.

Results

With elastography, the uterus was well delineated from the surrounding bowel. The myometrium was uniform in color in 49% of the cases, with a main color of purple or dark blue, indicating stiffer tissue. Fibroids and adenomyosis had different elastographic characteristics and different color patterns. In general, fibroids were darker and adenomyosis was brighter than adjacent myometrium. The agreement between elastography‐based diagnosis of fibroids and adenomyosis with MRI‐based diagnosis was excellent; with histology‐based diagnosis, agreement was substantial for fibroids and adenomyosis.

Conclusions

Elastography is able to identify clear discriminating characteristics of the uterus, fibroids and adenomyosis, and elastography‐based diagnoses are in excellent agreement with those of MRI. Agreement between elastography‐based diagnosis of adenomyosis and histology is substantial but not optimal. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Covariance structure of spatial and spatiotemporal processes
Authors: Guttorp Peter , Schmidt Alexandra M.
Published: May 2013

An important aspect of statistical modeling of spatial or spatiotemporal data is to determine the covariance function. It is a key part of spatial prediction (kriging). The classical geostatistical approach uses an assumption of isotropy, which yields circular isocorrelation curves. However, this is inappropriate for many applications, and several nonstationary approaches have been developed. Adding the temporal aspect, there is often interaction between time and space, requiring classes of nonseparable covariance structures. WIREs Comput Stat 2013, 5:279–287. doi: 10.1002/wics.1259

This article is categorized under:

Data: Types and Structure > Image and Spatial Data

Data: Types and Structure > Time Series, Stochastic Processes, and Functional Data
Stalled RNAP‐II molecules bound to non‐coding rDNA spacers are required for normal nucleolus architecture
Authors: Freire‐Picos M. A. , Landeira‐Ameijeiras V. , Mayán María D.
Published: May 2013

The correct distribution of nuclear domains is critical for the maintenance of normal cellular processes such as transcription and replication, which are regulated depending on their location and surroundings. The most well‐characterized nuclear domain, the nucleolus, is essential for cell survival and metabolism. Alterations in nucleolar structure affect nuclear dynamics; however, how the nucleolus and the rest of the nuclear domains are interconnected is largely unknown. In this report, we demonstrate that RNAP‐II is vital for the maintenance of the typical crescent‐shaped structure of the nucleolar rDNA repeats and rRNA transcription. When stalled RNAP‐II molecules are not bound to the chromatin, the nucleolus loses its typical crescent‐shaped structure. However, the RNAP‐II interaction with Seh1p, or cryptic transcription by RNAP‐II, is not critical for morphological changes. Copyright © 2013 John Wiley & Sons, Ltd.
Three New Coordination Compounds Based on 2‐Phenyl‐4‐quinolinecarboxylic Acid and Nitrogenous Neutral Ligands: Syntheses, Structural Features, and Properties
Authors: Hou Xiang‐Yang , Wang Xiao , Fu Feng , Wang Ji‐Jiang , Tang Long
Published: May 2013

Solvothermal reactions of 2‐phenyl‐4‐quinolinecarboxylic acid (Hpqba) with CdII, CoII, ZnII and/or 4,4′‐bipyridyl (4,4′‐bipy), 1,4‐bis(imidazol‐1‐ylmethyl)benzene (biyb), 2,2′‐bipyridyl (2,2′‐bipy) afford three new coordination compounds of stoichiometries [Cd(pqba)2(4,4′‐bipy)] (1), [Zn(pqba)2biyb] (2), and [Co3(pqba)6‐(2,2′‐bipy)2] (3). Compounds 1–3 were characterized by elements analysis, IR spectroscopy, thermogravimetry, and single‐crystal X‐ray diffraction study. Compound 1 has a two‐dimensional structure, whereas compound 2 consists of a one‐dimensional (1D) network, which is further expanded by π···π stacking interactions to form a 3D supramolecular structure. Complex 3 also exhibits a 3D supramolecular structure completely based on π···π stacking interactions. The pqba ligands adopt μ1‐k1,k1, μ1‐k1, μ2‐k1,k1, and μ2‐k1,k2 coordination modes for compounds 1, 2, and 3. The fluorescence properties were examined on compounds 1 and 2 in the solid state at room temperature. Magnetic susceptibility measurements indicate that in complex 3 antiferromagnetic coupling between adjacent CoII ions exist.
A General Rehabilitation Inpatient With Exercise‐Induced Vasculitis
Authors: Cushman Dan , Rydberg Leslie
Published: May 2013

While on our general inpatient rehabilitation floor, a 58‐year‐old man with no hematologic or dermatologic history developed an erythematous patch on his medial ankle that turned more purpuric, with a slight orange tint, and was associated with mild pruritus. The diagnosis of exercise‐induced vasculitis was made after initially being mistaken for cellulitis. This common exanthem is often misdiagnosed. Due to its association with exercise, the physiatrist should be aware of its presence in both the inpatient and outpatient settings.
Engines of Growth: The Productivity Advance of Indian Railways, 1874–1912
Authors: Bogart Dan , Chaudhary Latika
Published: May 2013

Railways were integral to the development of the Indian economy before World War I. This article presents new estimates of total factor productivity (TFP) for railways from 1874 to 1912, which highlight the strong performance of this key industrial sector. Railway-industry TFP growth was substantial averaging 2.3 percent per year and generating a 2.7 percent social savings for the Indian economy. A combination of factors contributed to TFP growth including greater capacity utilization, technological change, and improvements in organization and governance. Railways had higher TFP growth than most sectors in India and compared favorably with TFP growth in other countries.
Epichromatin is conserved in Toxoplasma gondii and labels the exterior parasite chromatin throughout the cell cycle
Authors: VANAGAS LAURA , DALMASSO MARIA C. , DUBREMETZ JEAN F. , PORTIANSKY ENRIQUE L. , OLINS DONALD E. , ANGEL SERGIO O.
Published: May 2013

Toxoplasma gondii is an apicomplexan intracellular protozoan parasite responsible for toxoplasmosis, a disease with considerable medical and economic impact worldwide. Toxoplasma gondii cells never lose the nuclear envelope and their chromosomes do not condense. Here, we tested the murine monoclonal antibody PL2-6, which labels epichromatin (a conformational chromatin epitope based on histones H2A and H2B complexed with DNA), in T. gondii cultured in human fibroblasts. This epitope is present at the exterior chromatin surface of interphase nuclei and on the periphery of mitotic chromosomes in higher eukaryotes. PL2-6 reacted with T. gondii H2A and H2B histones in Western blot (WB) assays. In addition, the antibody reacted with the nuclear fraction of tachyzoites, as a single band coincident with H2B histone. In the T. gondii tachyzoite stage, PL2-6 also had peripheral nuclear localization, as observed by epifluorescence/confocal microscopy and immunoelectron microscopy. Confocal analysis showed that epichromatin is slightly polarized to one face of the parasite exterior chromatin surface. In replicating tachyzoites, PL2-6 also labels the exterior chromatin surface, covering the face of both segregating nuclei, facing the plasma membrane of the mother cell. The possible role of epichromatin in T. gondii is discussed.
The role of the regeneration niche for the vertical stratification of vascular epiphytes
Authors: Wagner Katrin , Bogusch Wiebke , Zotz Gerhard
Published: May 2013

Vertical stratification of vascular epiphytes is frequently attributed to niche partitioning along microclimatic gradients but experimental confirmations of this notion are rare. This study investigates the role of the regeneration phase for the stratification of five bromeliad (Catopsis sessiliflora, Guzmania subcorymbosa, Tillandsia anceps, T. bulbosa and Werauhia gladioliflora) and seven aroid species (Anthurium acutangulum, A. brownii, A. clavigerum, A. durandii, A. friedrichsthalii, A. hacumense and A. scandens) in a Panamanian rain forest. We documented gradients of temperature, vapour pressure deficit and light (n = 10 d) as well as species height distributions (n = 11–120). Microclimatic gradients were substantial (maximal T and RH differences between strata: 5 °C and 18%, respectively) and mean attachment heights of the study species (range = 4–21 m) differed significantly. We tested sensitivity to recurrent drought (four treatments) during germination (all species, cumulative germination of 20 seeds, n = 3) and seedling growth (four aroid species, n = 25). Seedling survival of six aroid species transplanted to three heights (n = 27) was monitored in situ. Some species did not germinate under severe recurrent drought while others germinated at the same rate in all treatments. Seedlings of the most exposed species grew fastest under intermediate recurrent drought while those of the other three species grew fastest when kept constantly wet. Survival of transplanted seedlings did not depend on species attachment height, but this may be attributable to insufficient statistical power. Taken together, the results suggest that the stratification can be explained to a large degree by differential sensitivity to the vertical moisture gradient during the regeneration phase.
Interval Kalman Filtering in Navigation System Design for an Uninhabited Surface Vehicle
Authors: Motwani A , Sharma SK , Sutton R , Culverhouse P
Published: May 2013

This paper reports on the potential application of interval Kalman filtering techniques in the design of a navigation system for an uninhabited surface vehicle namedSpringer. The interval Kalman filter (IKF) is investigated for this task since it has had limited exposure for such usage. A state-space model of theSpringersteering dynamics is used to provide a framework for the application of the Kalman filter (KF) and IKF algorithms for estimating the heading angle of the vessel under erroneous modelling assumptions. Simulations reveal several characteristics of the IKF, which are then discussed, and a review of the work undertaken to date presented and explained in the light of these characteristics, with suggestions on potential future improvements.
A factor analytic study in bipolar depression, and response to lamotrigine
Authors: Mitchell Philip B. , Hadzi-Pavlovic Dusan , Evoniuk Gary , Calabrese Joseph R. , Bowden Charles L.
Published: May 2013

Objective

There have been no previous factor analytic studies of the Hamilton Depression Rating Scale (HDRS) in samples with bipolar I depression, and no investigations of the utility of any derived factors in determining treatment response in this condition. This study aimed to identify and compare factors of a 31-item version of the HDRS (HDRS-31) in large samples of patients with bipolar depression and Major Depressive Disorder (MDD), then examine the responsiveness of such factors to lamotrigine compared with placebo in the bipolar depressed sample.

Methods

This multivariate analytical study was performed on 2 large depressed samples (one bipolar and the other MDD) that had been recruited for separate, contemporaneous, double-blind placebo-controlled trials of lamotrigine. The 2 studies had similar designs and assessment tools, the major measures being the Montgomery–Asberg Depression Rating Scale (MADRS) and HDRS-31. To identify the constructs underlying the scale, exploratory factor analyses were conducted using HDRS-31 baseline scores. Treatment responsiveness in the bipolar depressed sample—as indicated by improvement in the total MADRS and HDRS-31, as well as HDRS factors—were examined using both a mixed-effects analysis and individual time-point t-tests.

Results

Seven factors of the HDRS-31 were identified: I—“depressive cognitions,” II—“psychomotor retardation,” III—“insomnia,” IV—“hypersomnia,” V—“appetite and weight change,” VI—“anxiety,” and VII—“anergia.” A significant therapeutic effect of lamotrigine in bipolar depression was found for the “depressive cognitions” factor (from week 3) and “psychomotor retardation” (from week 4).

Conclusion

This study has identified 7 factors of the HDRS in a large sample of patients with bipolar depression. The results suggest that that the clinical benefits of lamotrigine in acute bipolar depression are primarily upon depressive cognitions and psychomotor slowing.
Political Theology and the Dialectics of (Counter)Secularization
Authors: Fabbri Renaud
Published: May 2013

This article builds on Habermas's hypothesis of a post-secular world society and on Voegelin's philosophy of consciousness. It first analyzes the genesis of the post-secular hypothesis in the work of Habermas. It then looks at the historical roots of the post-secular world society since the Axial Age. Finally, it delineates the evolution of religious actors in modern societies, at the political and cognitive levels, focusing on the European Counter-revolutionaries, the Islamist and post-Islamist movements of the Middle East, and the Hindu Nationalists. The article concludes that Habermas's hypothesis provides a plausible alternative to neo-Schmittian theory of the Clash of Civilizations proposed by Huntington.
European integration, party strategies, and state restructuring: a comparative analysis
Authors: Dardanelli Paolo
Published: May 2013

To what extent and in what way does European integration fuel state restructuring? This is a long-standing but still not a fully answered question. While the theoretical literature suggests a positive link between the two, previous empirical studies have reached contrasting conclusions. The article offers an alternative testing of the proposition, centred on the role of party strategies as a causal mechanism, analysed across space and time. On the cross-sectional axis, it focusses on parties in Flanders and Wallonia (Belgium), Lombardy and Sicily (Italy), Catalonia and Andalusia (Spain), and Scotland and Wales (United Kingdom). On the cross-temporal axis, it focuses on four critical junctures connecting integration and state restructuring. It analyses the degree to which ‘Europe’ has been strategically used in connection to state restructuring and which conditions have been necessary and/or sufficient to that outcome. The analysis has been conducted on the basis of a Qualitative Comparative Analysis methodology. Five main results emerge: (1) overall, parties have generally exploited ‘Europe’ in connection with state restructuring to a limited extent only but in a few cases exploitation has been very intense and intimately linked to strategic turning points; (2) ‘Europe’ has overwhelmingly been used to support state restructuring; (3) the most intense use has been made by regional parties with a secessionist position and positive attitude to the EU; (4) ‘use of Europe’ is a product of a complex conjunctural effect of several conditions; (5) it has increased over time but is not a linear product of integration, a sharp drop can be observed between the two most recent time points. These findings show that European integration can indeed exercise causal influence upon state restructuring via party strategies but that this is highly contingent on the complex interaction of multiple factors.
Low-temperature muon spin rotation studies of the monopole charges and currents in Y doped Ho2Ti2O7
Authors: Chang L. J. , Lees M. R. , Balakrishnan G. , Kao Y.-J. , Hillier A. D.
Published: May 2013

In the ground state of Ho2Ti2O7 spin ice, the disorder of the magnetic moments follows the same rules as the proton disorder in water ice. Excitations take the form of magnetic monopoles that interact via a magnetic Coulomb interaction. Muon spin rotation has been used to probe the low-temperature magnetic behaviour in single crystal Ho2−xYxTi2O7 (x = 0, 0.1, 1, 1.6 and 2). At very low temperatures, a linear field dependence for the relaxation rate of the muon precession λ(B), that in some previous experiments on Dy2Ti2O7 spin ice has been associated with monopole currents, is observed in samples with x = 0 and 0.1. A signal from the magnetic fields penetrating into the silver sample plate due to the magnetization of the crystals is observed for all the samples containing Ho allowing us to study the unusual magnetic dynamics of Y doped spin ice.
p32 protein levels are integral to mitochondrial and endoplasmic reticulum morphology, cell metabolism and survival
Authors: Hu MengJie , Crawford Simon A. , Henstridge Darren C. , Ng Ivan H. W. , Boey Esther J. H. , Xu Yuekang , Febbraio Mark A. , Jans David A. , Bogoyevitch Marie A.
Published: May 2013

p32 [also known as HABP1 (hyaluronan-binding protein 1), gC1qR (receptor for globular head domains complement 1q) or C1qbp (complement 1q-binding protein)] has been shown previously to have both mitochondrial and non-mitochondrial localization and functions. In the present study, we show for the first time that endogenous p32 protein is a mitochondrial protein in HeLa cells under control and stress conditions. In defining the impact of altering p32 levels in these cells, we demonstrate that the overexpression of p32 increased mitochondrial fibrils. Conversely, siRNA-mediated p32 knockdown enhanced mitochondrial fragmentation accompanied by a loss of detectable levels of the mitochondrial fusion mediator proteins Mfn (mitofusin) 1 and Mfn2. More detailed ultrastructure analysis by transmission electron microscopy revealed aberrant mitochondrial structures with less and/or fragmented cristae and reduced mitochondrial matrix density as well as more punctate ER (endoplasmic reticulum) with noticeable dissociation of their ribosomes. The analysis of mitochondrial bioenergetics showed significantly reduced capacities in basal respiration and oxidative ATP turnover following p32 depletion. Furthermore, siRNA-mediated p32 knockdown resulted in differential stress-dependent effects on cell death, with enhanced cell death observed in the presence of hyperosmotic stress or cisplatin treatment, but decreased cell death in the presence of arsenite. Taken together, our studies highlight the critical contributions of the p32 protein to the morphology of mitochondria and ER under normal cellular conditions, as well as important roles of the p32 protein in cellular metabolism and various stress responses.
Epigenetics in the heart: the role of histone modifications in cardiac remodelling
Authors: Tingare Asmita , Thienpont Bernard , Roderick H. Llewelyn
Published: May 2013

Understanding the molecular mechanisms underlying cardiac development and growth has been a longstanding goal for developing therapies for cardiovascular disorders. The heart adapts to a rise in its required output by an increase in muscle mass and alteration in the expression of a large number of genes. However, persistent stress diminishes the plasticity of the heart, consequently resulting in its maladaptive growth, termed pathological hypertrophy. Recent developments suggest that the concomitant genome-wide remodelling of the gene expression programme is largely driven through epigenetic mechanisms such as post-translational histone modifications and DNA methylation. In the last few years, the distinct functions of histone modifications and of the enzymes catalysing their formation have begun to be elucidated in processes important for cardiac development, disease and cardiomyocyte proliferation. The present review explores how repressive histone modifications, in particular methylation of H3K9 (histone H3 Lys9), govern aspects of cardiac biology.
Epigenetic Mechanisms in Development and Disease
Authors: Murrell Adele , Hurd Paul J. , Wood Ian C.
Published: May 2013

Our advances in technology allow us to sequence DNA to uncover genetic differences not only between individuals, but also between normal and diseased cells within an individual. However, there is still a lot we have yet to understand regarding the epigenetic mechanisms that also contribute to our individuality and to disease. The 80th Biochemical Society Annual Symposium entitled Epigenetic Mechanisms in Development and Disease brought together some leading researchers in the field who discussed their latest insights into epigenetic mechanisms. Methylation of DNA has been the focus of much study from both a developmental perspective and imprinting of genes to its contribution to diseases such as cancer. Recently, the modification of methylcytosine to hydoxymethylcytosine within cells was uncovered, which opened a host of potential new mechanisms, and a flurry of new studies are underway to uncover its significance. Epigenetics is not confined to a study of DNA, and the post-translational modifications on the histone proteins have a significant role to play in regulating gene expression. There are many different modifications and, as shown at the Symposium, new variations used by cells are still being uncovered. We are some way to identifying how these modifications are added and removed and the protein complexes responsible for these changes. A focus on the function of the complexes and the interactions between individual modifications to regulate gene expression is advancing our knowledge, as discussed in the accompanying papers, although there are clearly plenty of opportunities for new breakthroughs to be made.
Enhanced dielectric, ferroelectric, and electrostrictive properties of Pb(Mg1/3Nb2/3)0.9Ti0.1O3 ceramics by ZnO modification
Authors: Promsawat Methee , Watcharapasorn Anucha , Tailor Hamel N. , Jiansirisomboon Sukanda , Ye Zuo-Guang
Published: May 2013

The effects of ZnO modification on the dielectric, ferroelectric, and electrostrictive properties of 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 (PMNT) ceramics are systematically studied in this work. The PMNT/xZnO (with x = 0, 0.4, 2.0, 4.0, and 11.0 mol. %) ceramics of complex perovskite structure were prepared by solid state reaction and sintering process. It is found that the maximum value of the dielectric constant decreases with increasing ZnO amount up to x = 4.0 mol. %, and then significantly increases with x = 11.0 mol. %. The temperature of maximum dielectric constant tends to increase, while the diffuseness of the dielectric peak is reduced, with increasing ZnO content. The remanent polarization and the coercive field increase with increasing ZnO concentration. The induced strain and the electrostrictive coefficient reach the maximum values of 0.10% (at E = 10 kV/cm) and 12.94 × 10−16 m2/V2, respectively, with x = 2.0 mol. % ZnO. The ceramic doped with a high ZnO content (11.0 mol. %) exhibits a macroscopically polar phase with a well-developed ferroelectric hysteresis loop and butterfly-shaped bipolar piezoelectric response. This enhanced long-range polarization and the resulting properties are attributed to the effects of the partial substitution of Zn2+ for Mg2+, which favors a higher degree of polar order and a lower degree of relaxor behavior.
Two-dimensional-spatial distribution measurement of electron temperature and plasma density in low temperature plasmas
Authors: Kim Young-Cheol , Jang Sung-Ho , Oh Se-Jin , Lee Hyo-Chang , Chung Chin-Wook
Published: May 2013

A real-time measurement method for two-dimensional (2D) spatial distribution of the electron temperature and plasma density was developed. The method is based on the floating harmonic method and the real time measurement is achieved with little plasma perturbation. 2D arrays of the sensors on a 300 mm diameter wafer-shaped printed circuit board with a high speed multiplexer circuit were used. Experiments were performed in an inductive discharge under various external conditions, such as powers, gas pressures, and different gas mixing ratios. The results are consistent with theoretical prediction. Our method can measure the 2D spatial distribution of plasma parameters on a wafer-level in real-time. This method can be applied to plasma diagnostics to improve the plasma uniformity of plasma reactors for plasma processing.
Coupled electron and ion nonlinear oscillations in a collisionless plasma
Authors: Karimov A. R.
Published: May 2013

Dynamics of coupled electrostatic electron and ion nonlinear oscillations in a collisionless plasma is studied with reference to a kinetic description. Proceeding from the exact solution of Vlasov-Maxwell equations written as a function of linear functions in the electron and ion velocities, we arrive at the two coupled nonlinear equations which describe the evolution of the system.
An atomistic description of the nematic and smectic phases of 4-n-octyl-4′ cyanobiphenyl (8CB)
Authors: Palermo Mattia Felice , Pizzirusso Antonio , Muccioli Luca , Zannoni Claudio
Published: May 2013

We report the results of atomistic molecular dynamics simulations of 4-n-octyl-4′ cyanobiphenyl (8CB) on samples of 750 and 3000 molecules showing the spontaneous formation of the nematic phase and then of smectic layers by gradually cooling down from the isotropic phase. Orientational, positional, and mixed order parameters, layer spacing, translational diffusion tensor components and their temperature dependence are reported. A detailed comparison with available experimental data validates the model and force field employed and clarifies the molecular organization of this important liquid crystal often used as reference smectic material.
Linear stability and sensitivity of the flow past a fixed oblate spheroidal bubble
Authors: Tchoufag J. , Magnaudet J. , Fabre D.
Published: May 2013

The stability properties of the wake past an oblate spheroidal bubble held fixed in a uniform stream are studied in the framework of a global linear analysis. In line with previous studies, provided the geometric aspect ratio of the bubble, χ, is large enough, the wake is found to be unstable only within a finite range of Reynolds number, Re. The neutral curves corresponding to the occurrence of the first two unstable modes are determined over a wide range of the (χ, Re) domain and the structure of the modes encountered along the two branches of each neutral curve is discussed. Then, using an adjoint-based approach, a series of sensitivity analyses of the flow past the bubble is carried out in the spirit of recent studies devoted to two-dimensional and axisymmetric rigid bodies. The regions of the flow most sensitive to an external forcing are found to be concentrated in the core or at the periphery of the standing eddy, as already observed with bluff bodies at the surface of which the flow obeys a no-slip condition. However, since the shear-free condition allows the fluid to slip along the bubble surface, the rear half of this surface turns out to be also significantly sensitive to disturbances originating in the shear stress, a finding which may be related to the well-known influence of surfactants on the structure and stability properties of the flow past bubbles rising in water.
Gating heat transport by manipulating convection in a magnetic nanofluid
Authors: Seshadri Indira , Gardner Alex , Mehta Rutvik J. , Swartwout Richard , Keblinski Pawel , Borca-Tasciuc Theo , Ramanath Ganpati
Published: May 2013

Gating thermal transport is a key requirement in smart heat exchangers used in a variety of applications such as electronics and energy generation. Here, we demonstrate a high on-off ratio thermal valve using magnetic nanofluids actuated by a non-uniform magnetic field. Using nanofluids comprised of magnetic nanoparticles in paraffin oil, we obtain on-off ratios as high as 16, which is more than 5-fold higher than that seen in comparable nanofluids with uniform magnetic fields. Analysis of these results using heat transfer modeling shows that the remarkable enhancement arises from magneto-thermally activated convection due to field gradients. Such convective thermal gating could be promising for applications.
Correlation between a photoelectron and a fragment ion in dissociative ionization of ethanol in intense near-infrared laser fields
Authors: Hosaka Kouichi , Yokoyama Atsushi , Yamanouchi Kaoru , Itakura Ryuji
Published: May 2013

The two dissociative ionization channels of ethanol (C2H5OH) induced by an intense near-infrared laser pulse (λ ∼ 783 nm), C2H5OH → CH2OH+ + CH3 + e− and C2H5OH → C2H5+ + OH + e−, are investigated using photoelectron-photoion coincidence method. It is shown that both the electronic ground state and the first electronically excited state of C2H5OH+ are produced at the moment of photoelectron emission. From the observed correlation between the electronic states of C2H5OH+ prepared at the moment of photoelectron emission and the kinetic energy release of the fragment ions, it is revealed that C2H5OH+ prepared in the electronic ground state at the photoelectron emission gains larger internal energy in the end than that prepared in the electronically excited state. The averaged internal energy of C2H5OH+ just before the dissociation is found to increase when the laser field intensity increases from 9 to 23 TW/cm2 and when the laser pulse duration increases from 35 to 800 fs.
The effect of Na+ and K+ doping on the properties of sol-gel deposited 2-hydroxy-1,4-naphthoquinone thin films
Authors: Al-Omari Mahmoud , Sel Kivanc , Mueller Anja , Mellinger Axel , Kaya Tolga
Published: May 2013

We describe the use of 2-hydroxy-1,4-naphthoquinone (HNQ) thin films as a potential water vapor and electrolyte sensing material towards the goal of non-invasive relative humidity and sweat detection. We have successfully made HNQ sol-gel thin films and studied the effects of sodium and potassium ions on their optical and electrical characteristics. Ultraviolet-visible absorbance and Fourier transform infrared spectroscopy measurements along with scanning electron microscopy demonstrated that we were able to dope HNQ thin films with Na+ and K+ ions, which are the main electrolyte contents in sweat. While the conductivity of thin films increased by at least an order of magnitude, energy band gaps decreased by doping HNQ with Na+ and K+ ions. Relative humidity test results showed that HNQ-based thin-films can be used as a sensing material for water vapor. Room temperature current-voltage measurements were also performed to determine the surface conductivity.
Obtaining the lattice energy of the anthracene crystal by modern yet affordable first-principles methods
Authors: Sancho-García J. C. , Aragó J. , Ortí E. , Olivier Y.
Published: May 2013

The non-covalent interactions in organic molecules are known to drive their self-assembly to form molecular crystals. We compare, in the case of anthracene and against experimental (electronic-only) sublimation energy, how modern quantum-chemical methods are able to calculate this cohesive energy taking into account all the interactions between occurring dimers in both first-and second-shells. These include both O(N6)- and O(N5)-scaling methods, Local Pair Natural Orbital-parameterized Coupled-Cluster Single and Double, and Spin-Component-Scaled-Møller-Plesset perturbation theory at second-order, respectively, as well as the most modern family of conceived density functionals: double-hybrid expressions in several variants (B2-PLYP, mPW2-PLYP, PWPB95) with customized dispersion corrections (–D3 and –NL). All-in-all, it is shown that these methods behave very accurately producing errors in the 1–2 kJ/mol range with respect to the experimental value taken into account the experimental uncertainty. These methods are thus confirmed as excellent tools for studying all kinds of interactions in chemical systems.
Effects of pressure, temperature, and hydrogen during graphene growth on SiC(0001) using propane-hydrogen chemical vapor deposition
Authors: Michon A. , Vézian S. , Roudon E. , Lefebvre D. , Zielinski M. , Chassagne T. , Portail M.
Published: May 2013

Graphene growth from a propane flow in a hydrogen environment (propane-hydrogen chemical vapor deposition (CVD)) on SiC differentiates from other growth methods in that it offers the possibility to obtain various graphene structures on the Si-face depending on growth conditions. The different structures include the (6√3 × 6√3)-R30° reconstruction of the graphene/SiC interface, which is commonly observed on the Si-face, but also the rotational disorder which is generally observed on the C-face. In this work, growth mechanisms leading to the formation of the different structures are studied and discussed. For that purpose, we have grown graphene on SiC(0001) (Si-face) using propane-hydrogen CVD at various pressure and temperature and studied these samples extensively by means of low energy electron diffraction and atomic force microscopy. Pressure and temperature conditions leading to the formation of the different structures are identified and plotted in a pressure-temperature diagram. This diagram, together with other characterizations (X-ray photoemission and scanning tunneling microscopy), is the basis of further discussions on the carbon supply mechanisms and on the kinetics effects. The entire work underlines the important role of hydrogen during growth and its effects on the final graphene structure.
Self-propelling uneven Leidenfrost solids
Authors: Dupeux Guillaume , Baier Tobias , Bacot Vincent , Hardt Steffen , Clanet Christophe , Quéré David
Published: May 2013

Placed on a hot surface, a solid that sublimates at atmospheric pressure can levitate on a cushion of its own vapor. Discovered by Leidenfrost, this effect has mostly been studied with liquids. Whereas the shape of a droplet is determined by a competition between gravity, surface tension, and stress in the vapor layer, a solid does not deform. In this paper, we show experimentally and theoretically that asymmetric mass distributions in a Leidenfrost solid can lead to a non homogenous vapor layer in which the lubrication flow generates a lateral force able to propel the body.
Stretching tethered polymer chains: Density functional approach
Authors: Borówko M. , Rżysko W. , Sokołowski S. , Sokołowska Z. , Usatenko Z.
Published: May 2013

We propose application of density functional theory to calculate the force acting on a selected segment of a tethered polymer chain that leads to stretching the chain. The density functional allows one to determine the effects due to the presence of other chains and solvent molecules. For high and moderate solvent densities the plot of the force versus the distance of the segment from the surface exhibits oscillatory behavior that has not been predicted by other approaches.
Dynamics of polymer translocation through a nanopore induced by different sizes of crowding agents
Authors: Chen Yuhao , Luo Kaifu
Published: May 2013

Using both theoretical analysis and Langevin dynamics simulations in two dimensions, we investigate the dynamics of polymer translocation through a nanopore induced by different sizes of the mobile crowding agents, where the crowding agents have equal area fraction ϕ and their diameters are σ and σb ⩾ σ at cis and trans sides, respectively. The chain prefers moving to the side with bigger crowding agents as expected, however, we find the size difference between crowding agents plays a complicated role in the probability of polymer translocation from cis to trans side, the translocation time τ and its distribution, and the translocation exponent. In particular, with increasing σb, the translocation probability shows a maximum value and τ has a minimum value. These results can be interpreted by the effective driving force, which always increases with increasing ϕ but has a maximum value with increasing σb.
Stimulated Raman scattering in the evanescent field of liquid immersed tapered nanofibers
Authors: Shan Liye , Pauliat Gilles , Vienne Guillaume , Tong Limin , Lebrun Sylvie
Published: May 2013

We present the first experimental demonstrations of stimulated Raman scattering in a liquid probed by the evanescent field of a tapered silica nanofiber. Raman scattering by a pure liquid, ethanol, or mixture of liquids, toluene diluted in ethanol, is investigated. Given the large choice of available materials for the medium surrounding the nanofiber, these demonstrations pave the way to the exploration of a new class of experiments and devices.
Toward a self-consistent model of the interaction between an ultra-intense, normally incident laser pulse with an overdense plasma
Authors: Debayle A. , Sanz J. , Gremillet L. , Mima K.
Published: May 2013

Following a recent work by Sanz et al. [Phys. Rev. E 85, 046411 (2012)], we elaborate upon a one-dimensional model describing the interaction between an ultra-intense, normally incident laser pulse and an overdense plasma. The analytical solutions of the reflected laser field, the electrostatic field, and the plasma surface oscillation are obtained within the cold-fluid approximation. The high-order harmonic spectrum is calculated from the exact solution of the plasma surface oscillations. In agreement with particle-in-cell simulations, two regimes of harmonic generation are predicted: for moderately relativistic laser intensities, or high plasma densities, the harmonic spectrum is determined by the discontinuity in the derivative of the reflected field when the electron plasma boundary oscillates across the fixed ion boundary. For higher intensities, the electron plasma boundary is confined inside the ion region and oscillates at relativistic velocities, giving rise to a train of reflected attosecond pulses. In both cases, the harmonic spectrum obeys an asymptotic ω−4 scaling. The acceleration of electrons and the related laser absorption efficiency are computed by a test particle method. The model self-consistently reproduces the transition between the “anomalous skin effect” and the “J × B” heating predicted by particle-in-cell simulations. Analytical estimates of the different scalings are presented.
Threshold improvement in uniformly lying helix cholesteric liquid crystal laser using auxiliary π-conjugated polymer active layer
Authors: Yoshida Hiroyuki , Shiozaki Yusuke , Inoue Yo , Takahashi Masaya , Ogawa Yasuhiro , Fujii Akihiko , Ozaki Masanori
Published: May 2013

We propose a device structure to lower the lasing threshold of a uniformly lying helix cholesteric liquid crystal (ChLC) laser. We place a π-conjugated polymer active layer beneath the ChLC layer to provide auxiliary gain, and demonstrate an improvement in the lasing threshold by a factor of 2.3. We also perform finite difference time domain calculations coupled with rate equations for a four-level system, and clarify the effect of the additional active layer on both the photonic density of states and the inversion population density. Although the addition of an extra layer lowers the photonic density of states, the gain provided by the auxiliary layer is sufficient to overcome the losses and decrease the lasing threshold. Our concept is useful for obtaining high-performance ChLC lasers.