bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetism and electron transport of MnyGa (1 < y < 2) nanostructures
Authors: Huh Y. , Kharel P. , Shah V. R. , Li X. Z. , Skomski R. , Sellmyer D. J.
Published: July 2013

Nanostructured MnyGa ribbons with varying Mn concentrations including Mn1.2Ga, Mn1.4Ga, Mn1.6Ga, and Mn1.9Ga were prepared using arc-melting and melt-spinning followed by a heat treatment. Our experimental investigation of the nanostructured ribbons shows that the material with y = 1.2, 1.4, and 1.6 prefers the tetragonal L10 structure and that with y = 1.9 prefers the D022 structure. We have found a maximum saturation magnetization of 621 emu/cm3 in Mn1.2Ga which decreases monotonically to 300 emu/cm3 as y reaches 1.9. Although both the L10- and D022-MnyGa samples show a high Curie temperature (Tc) well above room temperature, the value of Tc decreases almost linearly from 702 K for Mn1.9Ga to 551 K for Mn1.2Ga. All the ribbons are metallic between 2 K and 300 K but the Mn1.2Ga also shows a resistance minimum near 15 K. The observed magnetic properties of the MnyGa ribbons are consistent with the competing ferromagnetic coupling between Mn moments in the regular L10-MnGa lattice sites and antiferromagnetic coupling with excess Mn moments occupying Ga sites.
Communication: Multiple-timestep ab initio molecular dynamics with electron correlation
Authors: Steele Ryan P.
Published: July 2013

A time-reversible, multiple-timestep protocol is presented for ab initio molecular dynamics simulations using correlated, wavefunction-based underlying potentials. The method is motivated by the observation that electron correlation contributions to forces vary on a slower timescale than their Hartree-Fock counterparts. An efficient dynamics algorithm, involving short-timestep Hartree-Fock and long-timestep Møller-Plesset perturbation theory, is presented and tested. Results indicate stable trajectories and relative speedups comparable to those seen in force field-based multiple-timestep schemes, with the highest efficiency improvement occurring for large systems.
Tailored domain wall charges by individually set in-plane magnetic domains for magnetic field landscape design
Authors: Holzinger Dennis , Zingsem Norbert , Koch Iris , Gaul Alexander , Fohler Manuel , Schmidt Christoph , Ehresmann Arno
Published: July 2013

A method, a material system, and the physics for tailoring artificial magnetic field landscapes on micron and submicron length scales over a topographically flat surface in remanence are presented. KeV-He+ ion bombardment induced magnetic patterning was used for the creation of in-plane magnetized domains in Exchange Bias layer systems. This technology sets defined magnetic domain wall charges between the in-plane magnetic domains by individually set domain properties (magnitude and direction of anisotropy parameters) on both sides of the domain wall. The magnetic surface charge distribution was analyzed by magnetic force microscopy and compared to micromagnetic simulations.
An electronic structure reinterpretation of the organic semiconductor/electrode interface based on argon gas cluster ion beam sputtering investigations
Authors: Yun Dong-Jin , Chung JaeGwan , Jung Changhoon , Kim Ki-Hong , Baek WoonJoong , Han Hyouksoo , Anass Benayad , Park Gyeong-Su , Park Sung-Hoon
Published: July 2013

The effects of the Ar gas cluster ion beam (GCIB) sputtering process on the structural and chemical properties of organic material and the energy-level alignment at the organic semiconductor/electrode interface are studied. The Ar GCIB sputtering process causes no damage to the molecular orientation and structure of the pentacene layer. The thin-film phase (001 at 5.74°, 15.4 Å) in the X-ray diffraction patterns and the terrace-like structure in the atomic force microscope images are maintained even after the Ar GCIB sputtering process. Furthermore, there is no change in the chemical bonding state in the organic materials, including pentacene and poly(3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS). Finally, to investigate the preservation of the interface properties after the Ar GCIB sputtering process, the valence band structures of the pentacene/PEDOT:PSS and pentacene/Au structures are characterized using bottom-up (in situ ultraviolet photoemission spectroscopy (UPS) analysis with phased pentacene deposition) and top-down (in situ UPS analysis with Ar GCIB sputtering) methods, and the energy levels and chemical states are compared using the same sample. The Ar GCIB sputtering process causes no variation in the primary valence band structure, including the chemical state and configuration. Therefore, the energy-level alignment determined using the top-down method is comparable to that obtained using bottom-up method, since the Ar GCIB sputtering process is damage-free.
Study of dielectric loss mechanisms in Bi1.5MgNb1.5O7 thin film varactors
Authors: Gao Libin , Jiang Shuwen , Xiao Yong , Li Ruguan , Li Yanrong
Published: July 2013

The dielectric loss of parallel-plate Pt/Bi1.5MgNb1.5O7 (BMN)/Pt thin film varactors were investigated. The effects of four extrinsic loss mechanisms were discussed. The results showed that the loss mechanism of conduction electrons, local polar regions, and universal relaxation contributed little to the BMN thin film varactors. However, the losses owing to charged defects were found to be the mainly loss mechanism at low frequency (below 1 MHz). The experimental data were in good agreement with the ω1/3 power law. We studied the effect of charged defects mechanism using BMN thin films annealing in different air conditions. It is clearly seen that the charged defects were associated with oxygen vacancies. In the frequency range 100 MHz-6 GHz, the losses of BMN thin film varactors did no fit the charged defects mechanism very well, which were due to the additional losses induced by electrodes, parasitic capacitances, and test equipments. The study of extrinsic loss mechanisms provided useful information for the deposition, varactor design, and the dielectric properties optimization of the BMN thin films.
Effects of the imposed magnetic field on the production and transport of relativistic electron beams
Authors: Cai Hong-bo , Zhu Shao-ping , He X. T.
Published: July 2013

The effects of the imposed uniform magnetic field, ranging from 1 MG up to 50 MG, on the production and transport of relativistic electron beams (REBs) in overdense plasmas irradiated by ultraintense laser pulse are investigated with two-dimensional particle-in-cell numerical simulations. This study gives clear evidence that the imposed magnetic field is capable of effectively confining the relativistic electrons in space even when the source is highly divergent since it forces the electrons moving helically. In comparison, the spontaneous magnetic fields, generated by the helically moving electrons interplaying with the current filamentation instability, are dominant in scattering the relativistic electrons. As the imposed magnetic field was increased from 1 MG to 50 MG, overall coupling from laser to the relativistic electrons which have the potential to heat the compressed core in fast ignition was found to increase from 6.9% to 21.3% while the divergence of the REB increases significantly from 64° to 90°. The simulations show that imposed magnetic field of the value of 3–30 MG could be more suitable to fast-ignition inertial fusion.
Effect of placing GaAs solar cells on the optical rod prism of a concentrated photovoltaic
Authors: Chen Hsin-Chien , Chang Liann-Be
Published: July 2013

In a concentrated photovoltaic (CPV) solar cell system, placing an additional solar cell on an optical rod prism with parallel connection to the original cell generated more than 12.1 mA output current and 15.6% output power under the same illumination conditions. This mechanism provided a simple method to enhance the utility rate of CPV solar cells. Such a concept can be further applied to the aerospace industry and to the development of CPV solar energy.
Wind energy resources analysis of Western Greece coast in terms of sustainable environmental indicators and towards their community-based exploitation in South-East Europe
Authors: Karamanis Dimitris
Published: July 2013

Wind energy resources in the Ionian-Adriatic coast of South-East Europe were analyzed. Status of wind energy development in the countries of Greece, Albania, Montenegro, Bosnia-Herzegovina, and Croatia and regions of moderate and high wind potential at their west coasts were reviewed. The feasibility of the application of specific wind turbine generators with lower cut-in, cut-out, and rated speeds in moderate wind fields was investigated. The wind speed and direction as well as the availability, the duration, and the diurnal variation of several coastal sites in Western Greece were assessed, and the results were statistically analyzed as time-series or with the Weibull probability distribution function. The mean wind power densities were less than 200 W m−2 at 10 m, suggesting the limiting suitability of the sites for the usual wind energy applications. However, further technical-economical analysis revealed that the recent technological turbine improvements with lower cut-in and rated speeds make wind power viable even at moderate wind fields. Environmental indicators like energy payback period and avoided greenhouse emissions were determined to be significant for the utilization of wind energy resources in these coastal areas. Since the region is important for sea-related activities, the implementation of wind energy applications in the frame of cross-border cooperation should be prioritized.
In situ analyses on negative ions in the indium-gallium-zinc oxide sputtering process
Authors: Jia Junjun , Torigoshi Yoshifumi , Shigesato Yuzo
Published: July 2013

The origin of negative ions in the dc magnetron sputtering process using a ceramic indium-gallium-zinc oxide target has been investigated by in situ analyses. The observed negative ions are mainly O− with energies corresponding to the target voltage, which originates from the target and barely from the reactive gas (O2). Dissociation of ZnO−, GaO−, ZnO2−, and GaO2− radicals also contributes to the total negative ion flux. Furthermore, we find that some sputtering parameters, such as the type of sputtering gas (Ar or Kr), sputtering power, total gas pressure, and magnetic field strength at the target surface, can be used to control the energy distribution of the O− ion flux.
Communication: Optical cooling of trans-stilbene
Authors: Kovalenko S. A. , Dobryakov A. L. , Pollak E. , Ernsting N. P.
Published: July 2013

Trans-stilbene in n-hexane is excited with excess vibrational energy in the range 0–7000 cm−1. In the excited electronic state, the Raman linewidth of the ethylenic C=C stretching mode at 1570 cm−1 is followed with ∼100 fs time resolution. Upon excitation with substantial excess energy, the width of the peak is initially broad and then narrows within a few picoseconds, as observed previously by Iwata and Hamaguchi [Chem. Phys. Lett. 196, 462 (1992)]10.1016/0009-2614(92)85721-L. This narrowing is understood as being caused by cooling of the initially hot molecule, by the surrounding solvent. In this Communication, we report that upon excitation without excess energy, the width is initially relatively narrow and then broadens on a picosecond time scale. The broadening is attributed to heating of the molecule by solvent collisions. It follows that the nascent population in the excited electronic state is cold as compared with the solvent. Such reduction of the initial vibrational energy may affect the rate for the subsequent photoreaction, especially in the absence of the solvent.
Tunable double Dirac cone spectrum in bilayer α-graphyne
Authors: Leenaerts O. , Partoens B. , Peeters F. M.
Published: July 2013

Monolayer α-graphyne was recently proposed as a new all-carbon material having an electronic spectrum consisting of Dirac cones. Based on a first-principles investigation of bilayer α-graphyne, we show that the electronic band structure is qualitatively different from its monolayer form and depends crucially on the stacking mode of the two layers. Two stable stacking modes are found: a configuration with a gapless parabolic band structure, similar to AB stacked bilayer graphene, and another one which exhibits a doubled Dirac-cone spectrum. The latter can be tuned by an electric field with a gap opening rate of 0.3 eÅ.
Surface fractal evolution induced rubbing for rapid room temperature and transfer-free fabrication of graphene on flexible polymer substrate
Authors: Yu Yan , Jiang Shenglin , Zhou Wenli , Miao Xiangshui , Zeng Yike , Zhang Guangzu , He Jungang , Yi Jinqiao , Liu Wen
Published: July 2013

Graphene as functional layer on flexible polymers for stretchable applications have attracted much research interests, and the fabrication methods are of great importance. In this letter, rapid room temperature and transfer-free fabrication of few-layer graphene on flexible polymer substrates has been realized by rubbing method. This is achieved by the surface fractal evolution rubbing step which can evolve sandpaper surface to form relatively large area of smooth parts as self-lubricated smooth surface. The graphene displayed strong adhesion with flexible polymer substrates, which is benefit for applications. Physical mechanisms of rubbing steps and fabrication of graphene on polymers are studied.
Tunable photoresponse of epitaxial graphene on SiC
Authors: Sun Rujie , Zhang Ye , Li Kang , Hui Chao , He Ke , Ma Xucun , Liu Feng
Published: July 2013

We report photoresponse measurements from two comparable epitaxial graphene (EG) devices of different thicknesses (2-layer vs. ∼10-layer EG) made on SiC substrates. An asymmetric metal contact scheme was used in a planar configuration to form a Ti/EG/Pd junction. By moving the laser illumination across the junction, we observed an increased photocurrent signal resulting from local enhancement of electric field near the metal/EG contact. A maximum photoresponsivity of 1.11 mA/W without bias was achieved at the Pd/EG contact in the 10-layer EG device. Photocurrent was also observed under AM 1.5 illumination. Our experiments demonstrate the high tunability of this EG photodetector by varying EG thickness, metal leads, channel length, and/or illumination area.
Mechanical properties of irradiated single-layer graphene
Authors: Carpenter Corinne , Maroudas Dimitrios , Ramasubramaniam Ashwin
Published: July 2013

The mechanical properties of irradiated single-layer graphene sheets are determined as a function of inserted vacancy concentration. We find that the vacancy-induced crystalline-to-amorphous transition is accompanied by a brittle-to-ductile transition in the failure response of irradiated graphene sheets for inserted vacancy concentrations of 8%–12%. While point defects and larger voids appreciably degrade the strength of pristine graphene, we find that even heavily damaged samples (∼20% vacancies) exhibit tensile strengths of ∼30 GPa, in significant excess of those typical of engineering materials. Our results suggest that defect engineering of graphene is feasible without incurring a complete loss of its desirable mechanical properties.
Additivity of the dp-rank
Authors: Kaplan Itay , Onshuus Alf , Usvyatsov Alexander
Published: July 2013

The main result of this article is sub-additivity of the dp-rank. We also show that the study of theories of finite dp-rank cannot be reduced to the study of its dp-minimal types, and we discuss the possible relations between dp-rank and VC-density.
Understanding the regulatory and transcriptional complexity of the genome through structure
Authors: Mercer Tim R. , Mattick John S.
Published: July 2013

An expansive functionality and complexity has been ascribed to the majority of the human genome that was unanticipated at the outset of the draft sequence and assembly a decade ago. We are now faced with the challenge of integrating and interpreting this complexity in order to achieve a coherent view of genome biology. We argue that the linear representation of the genome exacerbates this complexity and an understanding of its three-dimensional structure is central to interpreting the regulatory and transcriptional architecture of the genome. Chromatin conformation capture techniques and high-resolution microscopy have afforded an emergent global view of genome structure within the nucleus. Chromosomes fold into complex, territorialized three-dimensional domains in concert with specialized subnuclear bodies that harbor concentrations of transcription and splicing machinery. The signature of these folds is retained within the layered regulatory landscapes annotated by chromatin immunoprecipitation, and we propose that genome contacts are reflected in the organization and expression of interweaved networks of overlapping coding and noncoding transcripts. This pervasive impact of genome structure favors a preeminent role for the nucleoskeleton and RNA in regulating gene expression by organizing these folds and contacts. Accordingly, we propose that the local and global three-dimensional structure of the genome provides a consistent, integrated, and intuitive framework for interpreting and understanding the regulatory and transcriptional complexity of the human genome.
Insights into neural crest development and evolution from genomic analysis
Authors: Simões-Costa Marcos , Bronner Marianne E.
Published: July 2013

The neural crest is an excellent model system for the study of cell type diversification during embryonic development due to its multipotency, motility, and ability to form a broad array of derivatives ranging from neurons and glia, to cartilage, bone, and melanocytes. As a uniquely vertebrate cell population, it also offers important clues regarding vertebrate origins. In the past 30 yr, introduction of recombinant DNA technology has facilitated the dissection of the genetic program controlling neural crest development and has provided important insights into gene regulatory mechanisms underlying cell migration and differentiation. More recently, new genomic approaches have provided a platform and tools that are changing the depth and breadth of our understanding of neural crest development at a “systems” level. Such advances provide an insightful view of the regulatory landscape of neural crest cells and offer a new perspective on developmental as well as stem cell and cancer biology.
Culturing Hybridoma Cell Lines for Monoclonal Antibody Production
Authors: Winzeler Alissa , Wang Jack T.
Published: July 2013

This protocol describes how to culture hybridoma cell lines (e.g., Thy1.1) for monoclonal antibody production. Supernatants harvested from such cultures can be used to purify various rodent neural cell types by immunopanning.
Purification and Culture of Retinal Ganglion Cells
Authors: Winzeler Alissa , Wang Jack T.
Published: July 2013

Retinal ganglion cells (RGCs) are the neurons that extend axons through the optic nerve, connecting and transmitting information from the retina to the brain. In mammals, RGCs receive information from bipolar and amacrine cells and synapse onto target cells in the lateral geniculate nucleus (LGN) as well as the superior colliculus. Methods for acute purification of RGCs from rodent retina by immunopanning followed by culture in a serum-free medium have facilitated the study of neuronal biology and function in a defined environment. These methods are introduced here, and modifications for achieving optimal RGC purity and culture are described.
Measuring Membrane Voltage with Fluorescent Proteins
Authors: Patti Jordan , Isacoff Ehud Y.
Published: July 2013

Measuring signal transduction in large numbers of cells with high spatial and temporal resolution is fundamental to studying information processing in the nervous system. DNA-encoded sensors have an advantage in that they can be introduced into an organism noninvasively and targeted to specific brain regions, cell types, or subcellular compartments. A variety of chimeric proteins that report transmembrane voltage have been developed. The prototype sensor, FlaSh, is a green fluorescent protein fused to a voltage-sensitive K+ channel, where voltage-dependent rearrangements in the channel induce changes in the protein's fluorescence. Subsequent sensors have refined this basic design using a monomeric voltage-sensing phosphatase domain from Ciona intestinalis and pairs of fluorescent proteins to produce a larger fluorescent signal. These sensors and their uses are discussed here.
Case Comment: The Legality of ‘Kettling’ after Austin
Authors: Oreb Naomi
Published: July 2013

This case comment considers the European Court of Human Rights decision of Austin v United Kingdom (2012) 55 EHRR 14. Austin claimed, unsuccessfully, that police kettling at a public protest in London amounted to a violation of her right to liberty under Article 5 of the European Convention of Human Rights. This case comment suggests that the court took an unexpected and unorthodox approach to the issue of ‘deprivation’ within Article 5. This decision may come to undermine the protections afforded by Article 5 and extend the current exceptions to Article 5 to an indefinite range of situations.
Biochemical studies of the multicopper oxidase (small laccase) from Streptomyces coelicolor using bioactive phytochemicals and site‐directed mutagenesis
Authors: Sherif Mohammed , Waung Debbie , Korbeci Bihter , Mavisakalyan Valentina , Flick Robert , Brown Greg , Abou‐Zaid Mamdouh , Yakunin Alexander F. , Master Emma R.
Published: July 2013

Multicopper oxidases can act on a broad spectrum of phenolic and non‐phenolic compounds. These enzymes include laccases, which are widely distributed in plants and fungi, and were more recently identified in bacteria. Here, we present the results of biochemical and mutational studies of small laccase (SLAC), a multicopper oxidase from Streptomyces coelicolor (SCO6712). In addition to typical laccase substrates, SLAC was tested using phenolic compounds that exhibit antioxidant activity. SLAC showed oxidase activity against 12 of 23 substrates tested, including caffeic acid, ferulic acid, resveratrol, quercetin, morin, kaempferol and myricetin. The kinetic parameters of SLAC were determined for 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid), 2,6‐dimethoxyphenol, quercetin, morin and myricetin, and maximum reaction rates were observed with myricetin, where kcat and Km values at 60°C were 8.1 (± 0.8) s−1 and 0.9 (± 0.3) mM respectively. SLAC had a broad pH optimum for activity (between pH 4 and 8) and temperature optimum at 60–70°C. It demonstrated remarkable thermostability with a half‐life of over 10 h at 80°C and over 7 h at 90°C. Site‐directed mutagenesis revealed 17 amino acid residues important for SLAC activity including the 10 His residues involved in copper coordination. Most notably, the Y229A and Y230A mutant proteins showed over 10‐fold increase in activity compared with the wild‐type SLAC, which was correlated to higher copper incorporation, while kinetic analyses with S929A predicts localization of this residue near the meta‐position of aromatic substrates.
Solid focal liver lesion characterisation with apparent diffusion coefficient ratios
Authors: Sutherland Tom , Steele Emma , van Tonder Frans , Yap Kelvin
Published: July 2013

Introduction

Non‐invasive characterisation of focal liver lesions using diffusion‐weighted imaging (DWI) has been heavily investigated and has shown substantial overlap between benign and malignant lesions. We have calculated a ratio of lesion to normal liver to determine if it improves accuracy for correct categorisation.

Method

All hepatic MRI studies performed between 1st April 2009 and 26th September 2011 were retrospectively reviewed. Patients with solid focal liver lesions in whom a diagnosis could be established and had lesions over 10 mm were included. Haemangiomas, cysts and patients with chronic liver disease were excluded. Apparent diffusion coefficient (ADC) values were calculated for each lesion and adjacent normal liver on breath hold DWI.

Results

Two hundred fifty‐eight studies were performed and 206 were excluded leaving 52 scans and 58 lesions of which 47 were benign and 11 were malignant. The mean ADC value for benign lesions was 1196.6 (two standard deviations (2SD) = ±399.9) and of benign liver 1101.5 (2SD = ±329.8) with a ratio of benign lesion to benign liver of 1.1005 (2SD = ±0.3783). The mean ADC of malignant lesions was 1153.0 (2SD = ±604.9) and malignant liver of 1080.7 (2SD = ±533.4) giving a malignant lesion to malignant liver ratio of 1.0890 (2SD = ±0.4975). None of these results were statistically significant (all P > 0.5).

Conclusion

DWI is unable to reliably differentiate solid benign lesions from solid malignant lesions.
Options for African agriculture in an era of high food and energy prices
Authors: Hazell Peter B. R.
Published: July 2013

In a world of high food and energy prices, Africa has an imperative to do a better job feeding itself and ensuring that its people are food secure. At the same time, there is a new business opportunity to work with the private sector in developing the continent's potential to produce significantly more food, raw materials, and biofuels for regional and world markets. A challenge for African policy makers is to find the right balance between a food security and a business agenda, and to ensure that the business agenda engages with large numbers of small farms. Agricultural development requires many things, but the fundamentals for Africa are developing markets, increasing agricultural productivity, and managing volatility. This cannot happen at sufficient scale and speed without strong public sector leadership, enabling policies and investments, and well‐focused implementation strategies.
Climate change, weather shocks, and violent conflict: a critical look at the evidence
Authors: Klomp Jeroen , Bulte Erwin
Published: July 2013

We use cross‐country data to explore whether temperature and rainfall shocks trigger violent conflict, or not. We include a wide range of country and time samples, and explore whether the impact of weather shocks is conditional on income or political regimes. Our overall conclusion is sobering. Notwithstanding the attention this topic has attracted from the media and policy makers, we find little robust evidence linking weather shocks to the onset of conflict.
Long‐term care insurance and market for aged care in Japan: Focusing on the status of care service providers by locality and organisational nature based on survey results
Authors: Kubo Makoto
Published: July 2013

Aim

The purpose of this paper is to examine the status of care service providers by locality and organisational nature.

Method

Questionnaires were sent to 9505 home‐based care service providers registered in the databases of 17 prefectures. The prefectures were selected according to population size.

Results

 Numerous for‐profit providers have newly entered the aged care service market and are operating selectively in Tokyo, a typical example of a metropolitan area. Furthermore, both for‐profit and non‐profit providers have suffered from a shortage of care workers and difficult management conditions, which tend to be more pronounced in Tokyo.

Conclusion

The market under long‐term care insurance was successful in terms of the volume of services, but most providers were sceptical as to whether competition in the market could facilitate quality care services.
Women's experience of induction of labor: a mixed methods study
Authors: Henderson Jane , Redshaw Maggie
Published: July 2013

Objective

To investigate women's experience of induction of labor.

Design

Mixed methods study.

Setting

English maternity units.

Sample

Women who gave birth in a two‐week period in late 2009, excluding women aged less than 16 years and women whose baby had died.

Methods

This study involved secondary analysis of data from questionnaires relating to care in childbirth. Women's experience of induction of labor was compared with that of women who had spontaneous labor by analysis of responses to structured survey questions. Responses to open questions relating to induction were analysed qualitatively.

Main outcome measures

Satisfaction with care, mode of delivery, experience of induction of labor.

Results

The response rate to the survey was 55.1% representing 5333 women, 20% of whom were induced. Nulliparous women, those with long‐term health problems, or specific pregnancy‐related problems were significantly more likely to be induced. Women who were induced were generally less satisfied with aspects of their care and significantly less likely to have a normal delivery. In the qualitative analysis the main themes that emerged concerned delay, staff shortages, neglect, pain and anxiety in relation to getting the induction started and once it was underway; and in relation to failed induction, the main themes were plans not being followed, wasted effort and pain, and feeling let down and disappointed.

Conclusions

Women having an induction were generally less satisfied with their care, suggesting the need for a focused service for these women to address their additional needs.
Factors attributing to the failure of endometrial sampling in women with postmenopausal bleeding
Authors: Visser Nicole C.M. , Breijer Maria C. , Herman Malou C. , Bekkers Ruud L.M. , Veersema Sebastiaan , Opmeer Brent C. , Mol Ben W.J. , Timmermans Anne , Pijnenborg Johanna M.A.
Published: July 2013

Objective

To determine which doctor‐ and patient‐related factors affect failure of outpatient endometrial sampling in women with postmenopausal bleeding, and to develop a multivariable prediction model to select women with a high probability of failed sampling.

Design

Prospective multicenter cohort study.

Setting

Three teaching hospitals in the Netherlands.

Population

Women presenting with postmenopausal bleeding with an indication for endometrial sampling.

Methods

Multivariable logistic regression was performed to evaluate the impact of doctor's training level and patient's characteristics on failure of sampling.

Main outcome measures

Failure of endometrial sampling, classified as technical failure or insufficient tissue for diagnosis.

Results

In 74 (20.8%) of the 356 included women, sampling technically failed, and in 84 (29.8%) the amount of tissue was insufficient for diagnosis. Nulliparity [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.8–7.9] and advanced age (OR 1.03 per year, 95% CI 1.00–1.06) were associated with technical failure. Advanced age was associated with insufficient sampling (OR 1.04 per year, 95% CI 1.01–1.07), and endometrial thickness >12 mm decreased the chance of insufficient sampling (OR 0.3, 95%CI 0.1–0.8). The prediction model for total failure had an area under the ROC curve of 0.64 (95% CI 0.58–0.70).

Conclusions

In women with postmenopausal bleeding, the failure rate of endometrial sampling is relatively high and is associated with nulliparity and advanced age. Endometrial thickness >12 mm decreased the chance of failure. A multivariable prediction model for total failure based on patient characteristics has a moderate capacity to discriminate between women at high or low risk of failure.
Feasibility and safety of laparoscopic total proctocolectomy with ileal pouch‐anal anastomosis for severe ulcerative colitis
Authors: Kawamura Junichiro , Hasegawa Suguru , Kawada Kenji , Yamaguchi Takashi , Nagayama Satoshi , Matsusue Ryo , Nomura Akinari , Sakai Yoshiharu
Published: July 2013

Introduction

The laparoscopic approach is accepted as a treatment option for patients with ulcerative colitis (UC) who are otherwise in good health. However, its application for patients with severe UC remains controversial. The purpose of this study was to evaluate the feasibility of the laparoscopic approach for severe UC cases. Short‐ and long‐term clinical outcomes after laparoscopic total proctocolectomy with ileal pouch‐anal anastomosis were compared between severe and mild‐to‐intermediate UC patients.

Methods

Cases treated between March 2002 and September 2010 were retrieved retrospectively from the database of Kyoto Medical Center and Kyoto University Hospital. Intraoperative complications and short‐ and long‐term clinical outcomes were compared.

Results

A total of 31 patients underwent laparoscopic total proctocolectomy with ileal pouch‐anal anastomosis. A comparison of short‐ and long‐term clinical outcomes after one‐ or two‐stage laparoscopic ileal pouch‐anal anastomosis between severe (n = 7) and mild‐to‐intermediate (n = 21) UC patients revealed no significant differences. The proportion of patients with restoration of intestinal continuity did not differ between the groups (severe: 86%, mild to intermediate: 95%; P = 0.69).

Conclusion

The present findings suggest that laparoscopic total proctocolectomy with ileal pouch‐anal anastomosis for severe UC patients could be a good alternative approach when performed by an experienced hand.
Evaluation of Attention‐Guiding Video Visualization
Authors: Kurzhals K. , Höferlin M. , Weiskopf D.
Published: July 2013

We investigate four different variants of attention‐guiding video visualization techniques that aim to help users distribute their attention equally among potential objects of interest: bounding box visualization, force‐directed visualization, top‐down visualization, grid visualization. Objects of interest are highlighted by rectangular shapes and then we concentrate on the manipulation of color, motion, and size. We conducted a controlled laboratory user study (n=25) to compare the four visualization techniques and the unmodified video material as baseline. We evaluated task performance and distribution of attention in a search task. These two properties become especially important when video material with numerous objects has to be observed. The distribution of attention was measured by eye tracking. Our results show that a more even distribution of attention between the objects can be achieved by attention‐guiding visualization, compared to unmodified video. Many participants feel more comfortable when they look at bounding boxes and the grid, but improvements in search task performance could not be confirmed.
Visual Analysis of Set Relations in a Graph
Authors: Xu Panpan , Du Fan , Cao Nan , Shi Conglei , Zhou Hong , Qu Huamin
Published: July 2013

Many applications can be modeled as a graph with additional attributes attached to the nodes. For example, a graph can be used to model the relationship of people in a social media website or a bibliographical dataset. Meanwhile, additional information is often available, such as the topics people are interested in and the music they listen to. Based on this additional information, different set relationships may exist among people. Revealing the set relationships in a network can help people gain social insight and better understand their roles within a community. In this paper, we present a visualization system for exploring set relations in a graph. Our system is designed to reveal three different relationships simultaneously: the social relationship of people, the set relationship among people's items of interest, and the similarity relationship of the items. We propose two novel visualization designs: a) a glyph‐based visualization to reveal people's set relationships in the context of their social networks; b) an integration of visual links and a contour map to show people and their items of interest which are clustered into different groups. The effectiveness of the designs has been demonstrated by the case studies on two representative datasets including one from a social music service website and another from an academic collaboration network.
An Interactive Analysis and Exploration Tool for Epigenomic Data
Authors: Younesy H. , Nielsen C.B. , Möller T. , Alder O. , Cullum R. , Lorincz M.C. , Karimi M.M. , Jones S.J.M.
Published: July 2013

In this design study, we present an analysis and abstraction of the data and tasks related to the domain of epigenomics, and the design and implementation of an interactive tool to facilitate data analysis and visualization in this domain. Epigenomic data can be grouped into subsets either by k‐means clustering or by querying for combinations of presence or absence of signal (on/off) in different epigenomic experiments. These steps can easily be interleaved and the comparison of different workflows is explicitly supported. We took special care to contain the exponential expansion of possible on/off combinations by creating a novel querying interface. An interactive heat map facilitates the exploration and comparison of different clusters. We validated our iterative design by working closely with two groups of biologists on different biological problems. Both groups quickly found new insight into their data as well as claimed that our tool would save them several hours or days of work over using existing tools.
Complexity Plots
Authors: Thiyagalingam Jeyarajan , Walton Simon , Duffy Brian , Trefethen Anne , Chen Min
Published: July 2013

In this paper, we present a novel visualization technique for assisting the observation and analysis of algorithmic complexity. In comparison with conventional line graphs, this new technique is not sensitive to the units of measurement, allowing multivariate data series of different physical qualities (e.g., time, space and energy) to be juxtaposed together conveniently and consistently. It supports multivariate visualization as well as uncertainty visualization. It enables users to focus on algorithm categorization by complexity classes, while reducing visual impact caused by constants and algorithmic components that are insignificant to complexity analysis. It provides an effective means for observing the algorithmic complexity of programs with a mixture of algorithms and black‐box software through visualization. Through two case studies, we demonstrate the effectiveness of complexity plots in complexity analysis in research, education and application.
TAMRESH – Tensor Approximation Multiresolution Hierarchy for Interactive Volume Visualization
Authors: Suter S.K. , Makhynia M. , Pajarola R.
Published: July 2013

Interactive visual analysis of large and complex volume datasets is an ongoing and challenging problem. We tackle this challenge in the context of state‐of‐the‐art out‐of‐core multiresolution volume rendering by introducing a novel hierarchical tensor approximation (TA) volume visualization approach. The TA framework allows us (a) to use a rank‐truncated basis for compact volume representation, (b) to visualize features at multiple scales, and (c) to visualize the data at multiple resolutions. In this paper, we exploit the special properties of the TA factor matrix bases and define a novel multiscale and multiresolution volume rendering hierarchy. Different from previous approaches, to represent one volume dataset we use but one set of global bases (TA factor matrices) to reconstruct at all resolution levels and feature scales. In particular, we propose a coupling of multiscalable feature visualization and multiresolution DVR through the properties of global TA bases. We demonstrate our novel TA multiresolution hierarchy based volume representation and visualization on a number of μCT volume datasets.
Gestaltlines
Authors: Brandes Ulrik , Nick Bobo , Rockstroh Brigitte , Steffen Astrid
Published: July 2013

We propose a general technique to visualize multivariate data sequences. It is based on a symbiotic combination of three powerful concepts from information visualization: sparklines, glyphs and gestalt theory. By visualizing several well‐known data sets in new ways we first demonstrate how explicit consideration of gestalt principles can be used to leverage visual perception capabilities for the identification of patterns such as trends, periodicities, change points, or outliers. A more detailed case study with complex and noisy data from a psychological experiment then demonstrates how basic design ideas for gestaltlines can be applied in less controlled, and thus more realistic, situations. The case study is complemented with reports on feedback from domain experts and a user study, both indicating that gestaltlines can be a convenient and valid means to explore and communicate patterns in micro‐visualizations.
Comparative Visualization of Tracer Uptake in In Vivo Small Animal PET/CT Imaging of the Carotid Arteries
Authors: Diepenbrock S. , Hermann S. , Schäfers M. , Kuhlmann M. , Hinrichs K.
Published: July 2013

Cardiovascular diseases are the main cause of death in the western world. Medical research on atherosclerosis is therefore of great interest and a very active research topic. We present a visualization system that supports scientists in exploring plaque development and evaluating the applicability of PET tracers for early diagnosis of cardiovascular diseases. In our application case a cone shaped cuff has been implanted around the carotid artery of ApoE knockout mice, fed with a high cholesterol western type diet. As a result, vascular lesions develop upstream and downstream from the cuff. Tracer uptake induced by these lesions needs to be analyzed in order to evaluate the effectiveness of different PET tracers. We discuss the approach previously utilized to perform this kind of analysis, the problems arising from in vivo image acquisition (in contrast to ex vivo) and the design process of our application. In close cooperation with domain experts we have developed new visualization techniques that display PET activity in the vessel wall and surrounding tissue in a single image. We use the vessel wall detected in the CT image to perform a normalized circular projection which allows the user to judge PET signal distribution in relation to the deformed vessel. Based on this projection a quantitative analysis of a defined region adjacent to the vessel wall can be performed and compared to the artery without the cuff.
Streamlines for Illustrative Real‐Time Rendering
Authors: Lawonn K. , Moench T. , Preim B.
Published: July 2013

Line drawing techniques are important methods to illustrate shapes. Existing feature line methods, e.g., suggestive contours, apparent ridges, or photic extremum lines, solely determine salient regions and illustrate them with separate lines. Hatching methods convey the shape by drawing a wealth of lines on the whole surface. Both approaches are often not sufficient for a faithful visualization of organic surface models, e.g., in biology or medicine. In this paper, we present a novel object‐space line drawing algorithm that conveys the shape of such surface models in real‐time. Our approach employs contour‐ and feature‐based illustrative streamlines to convey surface shape (ConFIS). For every triangle, precise streamlines are calculated on the surface with a given curvature vector field. Salient regions are detected by determining maxima and minima of a scalar field. Compared with existing feature lines and hatching methods, ConFIS uses the advantages of both categories in an effective and flexible manner. We demonstrate this with different anatomical and artificial surface models. In addition, we conducted a qualitative evaluation of our technique to compare our results with exemplary feature line and hatching methods.
Interactive Extraction and Tracking of Biomolecular Surface Features
Authors: Krone M. , Reina G. , Schulz C. , Kulschewski T. , Pleiss J. , Ertl T.
Published: July 2013

We present a coordinated‐view application for the analysis of molecular surface features like cavities, channels and pockets. Our tool employs object‐space ambient occlusion for the detection of such features and tracks them over time. It offers time‐dependent graphs of metrics concerning those features and allows analyzing the temporal relationship of the features, i.e. when they (dis)appear, split or merge and which features participate in each of these events. The automated analysis process is performed in real time while the user interactively explores a dynamic data set. The system supports linking and brushing to allow for a user‐guided visual analysis based on different aspects of the data. We demonstrate the effectiveness of our approach by applying it to data sets from biochemistry and report the insights that can be gained. We also evaluate the benefits of our method with respect to recent advancements in the field. The algorithmic pipeline leverages the computing power of modern GPUs, thus achieving interactive frame rates without any precomputation for fully dynamic data sets.
A primal/dual representation for discrete Morse complexes on tetrahedral meshes
Authors: Weiss Kenneth , Iuricich Federico , Fellegara Riccardo , De Floriani Leila
Published: July 2013

We consider the problem of computing discrete Morse and Morse‐Smale complexes on an unstructured tetrahedral mesh discretizing the domain of a 3D scalar field. We use a duality argument to define the cells of the descending Morse complex in terms of the supplied (primal) tetrahedral mesh and those of the ascending complex in terms of its dual mesh. The Morse‐Smale complex is then described combinatorially as collections of cells from the intersection of the primal and dual meshes. We introduce a simple compact encoding for discrete vector fields attached to the mesh tetrahedra that is suitable for combination with any topological data structure encoding just the vertices and tetrahedra of the mesh. We demonstrate the effectiveness and scalability of our approach over large unstructured tetrahedral meshes by developing algorithms for computing the discrete gradient field and for extracting the cells of the Morse and Morse‐Smale complexes. We compare implementations of our approach on an adjacency‐based topological data structure and on the PR‐star octree, a compact spatio‐topological data structure.
De novo malignancy post–liver transplantation: a single center, population controlled study
Authors: Chatrath Hemant , Berman Kenneth , Vuppalanchi Raj , Slaven James , Kwo Paul , Tector A. Joseph , Chalasani Naga , Ghabril Marwan
Published: July 2013

Background

With the growing numbers of liver transplant recipients, it is increasingly important to understand the risks of de novo malignancy after liver transplantation.

Aim

To characterize the incidence of de novo malignancy after liver transplantation compared with a control non‐transplant population.

Methods

We studied 534 Indiana state residents undergoing liver transplantation at our center between 1997 and 2004, followed through August 2010. The incidence and predictors of malignancy were determined. The standardized incidence ratio (SIR) of cancer in our cohort was compared with age‐, gender‐, and period‐matched state population using the Indiana State Cancer Registry.

Results

After a mean follow‐up of 5.7 ± 3.2 yr, 73 patients (13.7%) developed 80 cancers, with five‐ and 10‐yr incidence rates of 11.7% and 24.8%, respectively. These included 24 (30%) skin, 16 (20%) hematologic, and 40 (50%) solid tumors. The most common solid cancers were aerodigestive. Compared with matched state population, liver transplant recipients had significantly higher incidence of all cancers (SIR: 3.1, 95% CI [Confidence interval]: 2.9–3.2), skin (melanoma) (SIR: 5.8, 95% CI: 4.7–7.0), hematologic (SIR: 7.1, 95% CI: 6.3–8.0), and solid (SIR: 2.7, 95% CI: 2.5–2.8) tumors.

Conclusion

There is a significantly increased risk of de novo malignancies after liver transplantation, highlighting the need for surveillance strategies in this population.