bluuebunny/crossref_metadata_2025 huggingface dataset:
Biomarker validation and testing
Authors: Hayes Daniel F.
Published: October 2014

A tumor biomarker is a molecular or process‐based change that reflects the status of an underlying malignancy. A tumor biomarker may be identified and measured by one or more assays, or tests, for the biomarker. Increasingly, tumor biomarker tests are being used to drive patient management, either by identifying patients who do not require any, or any further, treatment, or by identifying patients whose tumors are so unlikely to respond to a given type of treatment that it will cause more harm than good. A tumor biomarker assay should only be used to guide management if it has analytical validity, meaning that it is accurate, reproducible, and reliable, and if it has been shown to have clinical utility. The latter implies that high levels of evidence are available that demonstrate that application of the tumor biomarker test for a given use context results in better outcomes, or similar outcomes with less cost, than if the assay were not applied. Use contexts include risk categorization, screening, differential diagnosis, prognosis, prediction of therapeutic activity or monitoring disease course. Very few tumor biomarker tests have passed these high bars for routine clinical application. However, if tumor biomarker tests are going to be used to drive patient care, than an understanding, and careful assessment, of these concepts are essential, since “A Bad Tumor Biomarker Test Is as Bad as a Bad Drug.”
Detection of glyco‐mucin profiles improves specificity of MUC16 and MUC1 biomarkers in ovarian serous tumours
Authors: Ricardo Sara , Marcos-Silva Lara , Pereira Daniela , Pinto Rita , Almeida Raquel , Söderberg Ola , Mandel Ulla , Clausen Henrik , Felix Ana , Lunet Nuno , David Leonor
Published: October 2014

The CA125 assay detects circulating MUC16 and is one of the most widely used cancer biomarkers for the follow‐up of ovarian cancer. We previously demonstrated that detection of aberrant cancer‐associated glycoforms of MUC16 as well as MUC1 in circulation could improve the yield of these serum assays. Our aim was to refine ovarian cancer biomarkers by detection of aberrant glycoforms (Tn, STn, and T) of MUC16 and MUC1 in ovarian cancer tissue using Proximity Ligation Assays (PLA).

We studied two series of serous ovarian tumours, a pilot series of 66 ovarian tumours (27 cystadenomas, 16 borderline tumours and 23 adenocarcinomas) from Centro Hospitalar S. João, Porto and a validation series of 89 ovarian tumours (17 cystadenomas, 25 borderline tumours and 47 adenocarcinomas) from the Portuguese Institute of Oncology Francisco Gentil, Lisbon.

PLA reactions for MUC16/Tn, MUC16/STn, MUC1/Tn and MUC1/STn were negative in benign lesions but often positive in borderline and malignant lesions, in both series. An even better yield was obtained based on positivity for any of the four glyco‐mucin profiles, further increasing sensitivity to 72% and 83% in the two series, respectively, with 100% specificity. The strategy is designated glyco‐mucin profiling and provides strong support for development of PLA‐based serum assays for early diagnosis.
Agomelatine-induced liver injury in a patient with choledocholithiasis
Authors: Eder Piotr , Permoda-Osip Agnieszka , Majewski Przemyslaw , Linke Krzysztof , Rybakowski Janusz K.
Published: October 2014

Objective

A case of agomelatine-induced hepatotoxicity is described in a 47-year female patient who has received the drug, 25 mg/day, for 4 months, for the treatment of depression.

Methods

The patient was admitted to the Department of Gastroenterology because of fatigue and nausea, with concomitant elevation of alanine aminotransferase (ALT), 550 U/L, and asparagine aminotransferase (AST), 300 U/L.

Results

Liver biopsy showed diffuse lymphocyte infiltration in the dilated portal spaces without lesion of hepatic lobules. Several weeks after stopping agomelatine, the liver enzymes returned to normal. Subsequently, small gallstones in common bile duct were detected and removed by the endoscopic sphincterotomy.

Conclusions

It is hypothesized that choledocholithiasis could theoretically increase a risk of developing agomelatine-induced hepatotoxicity in this patient. Any pre-existing liver disease should be a contraindication for treatment with agomelatine.
THE DEVELOPMENT OF SUBORDINATE CLAUSES IN GERMAN AND SWEDISH AS L2S
Authors: Baten Kristof , Håkansson Gisela
Published: October 2014

In this article, we aim to contribute to the debate about the use of subordination as a measure of language proficiency. We compare two theories of SLA—specifically, processability theory (PT; Pienemann, 1998) and dynamic systems theory (DST; de Bot, Lowie, & Verspoor, 2007)—and, more particularly, how they address the development of subordinate clauses. Whereas DST uses measures from the complexity, accuracy, and fluency research tradition (see Housen & Kuiken, 2009), PT uses the emergence criterion to describe language development. We focus on the development of subordinate clauses and compare how subordination as such is acquired and how the processing procedures related to a specific subordinate clause word order are acquired in the interlanguage of second language German and Swedish learners. The learners’ language use shows that the use of subordination (as measured by a subordination ratio) fluctuates extensively. From the beginning of data collection, all learners use subordinate clauses, but their use of subordinate clauses does not increase linearly over time, which is expected by DST. When focusing on processability and the emergence of subordinate clause word order, however, a clear linear developmental sequence can be observed, revealing a clear difference between the nonacquisition and the acquisition of the subordinate clause word order rules. Our learner data additionally reveal a different behavior regarding lexical and auxiliary or modal verbs.
Portfolio choice and longevity risk in the late seventeenth century: a re-examination of the first English tontine
Authors: Milevsky Moshe A.
Published: October 2014

Tontines and life annuities both insure against longevity risk by guaranteeing (pension) income for life. The optimal choice between these two mortality-contingent claims depends on personal preferences for consumption and risk. And, while pure tontines are unavailable in the twenty-first century, the first longevity-contingent claim (and debt) issued by the English government in the late seventeenth century offered a choice between the two. This article analyzes financial and economic aspects of King William's 1693 tontine that have not received attention in the literature. In particular, it compares the stochastic present value (SPV) of the tontine vs the life annuity and discusses characteristics of investors who selected one versus the other. Finally, the article examines the issue of whether high reported tontine survival rates should be attributed to anti-selection or fraud. In sum, this article is an empirical examination of annuitization decisions made by actual investors in the late seventeenth century.
Is there a benefit of bilingualism for executive functioning?
Authors: KLEIN RAYMOND M.
Published: October 2014

Scholars and educators were once concerned that encouraging children to learn more than one language might have adverse cognitive consequences (Darcy, 1953). And for some linguistic capacities (e.g., fluency, vocabulary) this is often true (Bialystok, Craik & Luk, 2012). Unfortunately, such individual costs might discourage governmental policies that are aimed at fostering multi-lingualism, despite its widely acknowledged societal benefits. Peal & Lambert (1962) helped overcome this concern and through her “myth-dispelling” efforts and prodigious empirical output, Bialystok has pushed the pendulum of opinion in the opposite direction.
The bilingual advantage in the Stroop task: simultaneous vs. early bilinguals
Authors: SABOURIN LAURA , VĪNERTE SANTA
Published: October 2014

The Stroop task has become a popular paradigm in investigations of bilingual cognitive control. While several studies show a cognitive control advantage for bilinguals, recent studies have countered these findings. The present study investigates two factors that may account for conflicting results: participant grouping and task difficulty. While we find no differences between simultaneous and early bilinguals (age groups traditionally both classified as “early” bilinguals) when the task uses only one language, we find a significant difference between the two when languages are mixed. We suggest treating the two groups as distinct, and note the importance of the bilingual context.
Prädiktoren der Behandelbarkeit nach § 64 StGB aus Therapeutensicht
Authors: Querengässer Jan , Hoffmann Klaus , Ross Thomas
Published: October 2014

Einleitung: Der Maßregelvollzug nach § 64 StGB kämpft mit steigender Belegung und hohen Erledigungsquoten. Zahlreiche Studien untersuchten daher behandlungsprognostisch relevante Patienteneigenschaften. Deren Gesamtschau ergibt ein uneinheitliches Bild von meist schwachen Prädiktoren. Zielsetzung: Beantwortet werden soll im Wesentlichen 1) inwieweit die empirischen Befunde der praktischen Behandlungserfahrung entsprechen; 2) welche weiteren Prädiktoren sich daraus ergeben.

Methodik: Anhand von Fragebögen schätzten 35 MRV-Therapeuten den prognostischen Wert von 30 Prädiktorvariablen ein. Die Eigennennung weiterer wurde erbeten.

Ergebnisse: Trotz deutlicher Heterogenität der Einschätzungen spiegeln sich gesicherte empirische Befunde wider, z. B. intrinsische Motivation als positiver und psychopathische Persönlichkeitszüge als negativer Prognosefaktor für den Behandlungserfolg. Weitere Variablen umfassen Aspekte delinquenter Sozialisation als negative Prädiktoren – Intelligenz, weibliches Geschlecht, Beziehungs- und sprachliche Ausdrucksfähigkeit als positive. Schlussfolgerung: Die Prognosefaktoren für den Behandlungserfolg nach § 64 StGB werden in der Praxis uneinheitlich bewertet. Als Mediator kommt die individuell verschiedene Behandlungserfahrung in Frage.
Pediatric Psychopharmacological Research in the Post EU Regulation 1901/2006 Era
Authors: Schmäl Christine , Becker Katja , Berg Ruth , Brünger Michael , Lehmkuhl Gerd , Oehler Klaus-Ulrich , Ruppert Thorsten , Staudter Claus , Trott Götz-Erik , Dittmann Ralf W.
Published: October 2014

Although the use of psychotropic medications in child and adolescent psychiatry in Germany is on the increase, most compounds are in fact prescribed “off-label” because of a lack of regulatory approval in these age groups. In 2007, the European Parliament introduced Regulation 1901/2006 concerning medicinal products in pediatric populations, with a subsequent amendment in the form of Regulation 1902/2006. The main aim of this legislation was to encourage research and clinical trials in children and adolescents, and thus promote the availability of medications with marketing authorization for these age groups. Furthermore, initiatives such as the European 7th Framework Program of the European Union now offer substantial funding for pediatric pharmacological research. At a recent Congress of the German Society for Child and Adolescent Psychiatry and Psychotherapy (DGKJP), experts from the field and the pharmaceutical industry held a symposium with lay representatives in order to discuss attitudes toward, and experience with, pediatric psychopharmacology research in Germany since 2007. Several areas of concern were identified. The present paper derives from that symposium and provides an overview of these opinions, which remain crucial to the field. A wider discussion of how to facilitate psychopharmacological research in Germany in order to optimize the treatment and welfare of children and adolescents with psychiatric disorders is now warranted.
The Digit Span Backwards Task
Authors: Hilbert Sven , Nakagawa Tristan T. , Puci Patricia , Zech Alexandra , Bühner Markus
Published: October 2014

Abstract. The “digit span backwards” (DSB) is the most commonly used test in clinical neuropsychology to assess working memory capacity. Yet, it remains unclear how the task is solved cognitively. The present study was conducted to examine the use of visual and verbal cognitive strategies in the DSB. Further, the relationship between the DSB and a complex span task, based on the Simultaneous Storage and Processing task ( Oberauer et al., 2003 ), was investigated. Visualizers performed better than verbalizers in the dual task condition (rPB = .23) only when the relevant digits were presented optically. Performance in the DSB correlated only weakly with the complex span task in all conditions (all τ ≤ .21). The results indicate that the processing modality is determined by the preference for a cognitive strategy rather than the presentation modality and suggest that the DSB measures different working aspects than commonly used experimental working memory tasks.
Exploring Outcome and Validity of the GAF in Psychiatric Inpatient	Care
Authors: Sonesson Ove , Arvidsson Hans , Tjus Tomas
Published: October 2014

Abstract. A small number of studies have investigated predictive factors in relation to the Global Assessment of Functioning (GAF) scale. This study aimed to explore the influence of clinical and socio-demographic factors in a psychiatric inpatient setting in relation to treatment outcome measured by the GAF. The studied psychiatric inpatient sample consisted of 816 episodes of care, with GAF ratings made at both admission and discharge. Multiple linear regressions were performed to analyze what variables predicted GAF scores at admission and at discharge. Significant predictors of GAF scores at admission were age, schizophrenia, other psychotic disorders, and no registered diagnosis. GAF scores at admission, patients’ diagnoses, and ward affiliation were able to significantly predict GAF at discharge. Specialized wards did not necessarily deliver the best treatment results in spite of their diagnostic specialization. This study provides support to the construct validity of the GAF when used as a measure of outcome.
Quantum signatures of a molecular nanomagnet in direct magnetocaloric measurements
Authors: Sharples Joseph W. , Collison David , McInnes Eric J. L. , Schnack Jürgen , Palacios Elias , Evangelisti Marco
Published: October 2014

Geometric spin frustration in low-dimensional materials, such as the two-dimensional kagome or triangular antiferromagnetic nets, can significantly enhance the change of the magnetic entropy and adiabatic temperature following a change in the applied magnetic field, that is, the magnetocaloric effect. In principle, an equivalent outcome should also be observable in certain high-symmetry zero-dimensional, that is, molecular, structures with frustrated topologies. Here we report experimental realization of this in a heptametallic gadolinium molecule. Adiabatic demagnetization experiments reach ~200 mK, the first sub-Kelvin cooling with any molecular nanomagnet, and reveal isentropes (the constant entropy paths followed in the temperature-field plane) with a rich structure. The latter is shown to be a direct manifestation of the trigonal antiferromagnetic net structure, allowing study of frustration-enhanced magnetocaloric effects in a finite system.
Chromatographic characteristics of water-soluble vitamins with irradiation processing and its application
Authors: Li Ying , Lv Changyin , Sun Qiang , Zhao Ying , Li Yunjing
Published: October 2014

The HPLC determination method combined with riboflavin, which has sensitive irradiation characteristics, could be used for 60Co dose measurement.
C(sp2)–C(sp2) cross coupling reaction catalyzed by a water-stable palladium complex supported onto nanomagnetite particles
Authors: Azadbakht Tahereh , Zolfigol Mohammad Ali , Azadbakht Reza , Khakyzadeh Vahid , Perrin David M.
Published: October 2014

A new palladium nanoparticles-based magnetic catalyst, which is stable in water, has been successfully synthesized, characterized and employed for the Suzuki reaction.
Systematic modifications of alkane-based molecular gelators and the consequences to the structures and properties of their gels
Authors: Rogers Michael A. , Weiss Richard G.
Published: October 2014

Structural development of simple molecular gelators based on n-alkanes and the properties of their complex gels.
Sc(OTf)3-mediated 1,3-dipolar cycloaddition–ring cleavage–rearrangement: a highly stereoselective access to Z-β-enaminonitriles
Authors: Wang Ying-chun , Xie Yu-yang , Tan Xian-chun , Wang Heng-shan , Pan Ying-ming
Published: October 2014

In this work, a novel and highly stereoselective synthesis of Z-β-enaminonitriles from azides and α,β-unsaturated nitriles is reported.
Ametantrone-based compounds as potential regulators of Tau pre-mRNA alternative splicing
Authors: Artigas Gerard , López-Senín Paula , González Carlos , Escaja Núria , Marchán Vicente
Published: October 2014

Ligands with a preferred binding site in the bulged region of the stem–loop structure of Tau pre-mRNA have been identified by dynamic combinatorial chemistry.
Synthesis of coenzyme A thioesters using methyl acyl phosphates in an aqueous medium
Authors: Pal Mohan , Bearne Stephen L.
Published: October 2014

RegioselectiveS-acylation of coenzyme A is achieved under aqueous conditions using various aliphatic and aromatic carboxylic acids activated as their methyl acyl phosphate monoesters.
A facile approach to tryptophan derivatives for the total synthesis of argyrin analogues
Authors: Chen Chou-Hsiung , Genapathy Sivaneswary , Fischer Peter M. , Chan Weng C.
Published: October 2014

Utilising a chiral auxiliary-facilitated Strecker amino acid synthesis strategy, indole-substituted (S)-tryptophans have been obtained from corresponding indoles; the former in turn were used for the synthesis of a potent antibacterial agent, argyrin and its analogues.
Flexible cage-like carbon spheres with ordered mesoporous structures prepared via a soft-template/hydrothermal process from carboxymethylcellulose
Authors: Wu Qiong , Li Wei , Tan Jia , Liu Shouxin
Published: October 2014

Carbon microspheres with flexible surface morphology and ordered mesoporous structure can be controllably obtained via a soft-template/hydrothermal process.
Nanocomposites based on Hofmann-type structure NiII(pz)[NiII(CN)4] (pz = pyrazine) nanoparticles for reversible iodine capture
Authors: Massasso G. , Rodriguez-Castillo M. , Long J. , Grandjean A. , Onida B. , Guari Y. , Guerin Ch. , Larionova J.
Published: October 2014

Hybrid nanocomposites based on nanoparticles with the Hofmann-type structure NiII(pz)[NiII(CN)4] (where pz = pyrazine) confined into mesoporous silica or porous glass pearls were synthesised and studied for efficient iodine capture from solution.
Late stages of the synchronized macrophage fusion in osteoclast formation depend on dynamin
Authors: Verma Santosh K. , Leikina Evgenia , Melikov Kamran , Chernomordik Leonid V.
Published: October 2014

Macrophage fusion that leads to osteoclast formation is one of the most important examples of cell–cell fusion in development, tissue homoeostasis and immune response. Protein machinery that fuses macrophages remains to be identified. In the present study, we explored the fusion stage of osteoclast formation for RAW macrophage-like murine cells and for macrophages derived from human monocytes. To uncouple fusion from the preceding differentiation processes, we accumulated fusion-committed cells in the presence of LPC (lysophosphatidylcholine) that reversibly blocks membrane merger. After 16 h, we removed LPC and observed cell fusion events that would normally develop within 16 h develop instead within 30–90 min. Thus, whereas osteoclastogenesis, generally, takes several days, our approach allowed us to focus on an hour in which we observe robust fusion between the cells. Complementing syncytium formation assay with a novel membrane merger assay let us study the synchronized fusion events downstream of a local merger between two plasma membranes, but before expansion of nascent membrane connections and complete unification of the cells. We found that the expansion of membrane connections detected as a growth of multinucleated osteoclasts depends on dynamin activity. In contrast, a merger between the plasma membranes of the two cells was not affected by inhibitors of dynamin GTPase. Thus dynamin that was recently found to control late stages of myoblast fusion also controls late stages of macrophage fusion, revealing an intriguing conserved mechanistic motif shared by diverse cell–cell fusion processes.
Otitis Media—Red Flags for Management: American Academy of Otolaryngology; Head and Neck Surgery 2013 Clinical Practice Guideline for Tympanostomy Tube Insertion
Authors: Harrison Melody
Published: October 2014

Otitis media with effusion (OME) is described as a collection of fluid in the middle ear, without signs or symptoms of acute ear infection (
Stool, Berg, Berman, & Carney, 1994). The accumulated fluid decreases the ability of both the tympanic membrane (eardrum) and the ossicles in the middle ear to vibrate, resulting in a mild conductive hearing loss. Although 28 decibels (dB) is the average hearing loss associated with OME, the range is quite wide. While some children experience no hearing loss, about 20% have hearing loss of 35 dB or greater (
Gravel, 2003).
Using experimental data and a contracted basis Lanczos method to determine an accurate methane potential energy surface from a least squares optimization
Authors: Wang Xiao-Gang , Carrington Tucker
Published: October 2014

We obtain an accurate methane potential energy surface (PES) by starting with the ab initio PES of Schwenke and Partridge [Spectrochim. Acta A 57, 887 (2001)] and adjusting 5 of their parameters to reproduce 40 reliable experimentally determined vibrational levels of CH4. The 40 levels include all 35 levels in polyads up to and including the Octad and 5 levels in the Tetradecad. The Tetradecad levels are obtained from direct experimental transitions. The fit reduces the root mean square deviation of these 40 levels from 4.80 cm−1 to 0.28 cm−1. The new PES ought to aid in the analysis of the Tetradecad. To further test the accuracy of the new PES, vibrational levels are computed for CH4, CH3D, CHD3, and 13CH4 and are compared with the extensive experimental data. The errors are all within about 1 cm−1 except for a few cases.
Many-body effects on the structures and stability of Ba2+Xen (n = 1–39, 54) clusters
Authors: Abdessalem Kawther , Habli Héla , Ghalla Houcine , Yaghmour Saud Jamil , Calvo Florent , Oujia Brahim
Published: October 2014

The structures and relative stabilities of mixed Ba2+Xen (n = 1–39, 54) clusters have been theoretically studied using basin-hopping global optimization. Analytical potential energy surfaces were constructed from ab initio or experimental data, assuming either purely additive interactions or including many-body polarization effects and the mutual contribution of self-consistent induced dipoles. For both models the stable structures are characterized by the barium cation being coated by a shell of xenon atoms, as expected from simple energetic arguments. Icosahedral packing is dominantly found, the exceptional stability of the icosahedral motif at n = 12 being further manifested at the size n = 32 where the basic icosahedron is surrounded by a dodecahedral cage, and at n = 54 where the transition to multilayer Mackay icosahedra has occurred. Interactions between induced dipoles generally tend to decrease the Xe-Xe binding, leading to different solvation patterns at small sizes but also favoring polyicosahedral growth. Besides attenuating relative energetic stability, many-body effects affect the structures by expanding the clusters by a few percents and allowing them to deform more.
Radiation asymmetries during disruptions on DIII-D caused by massive gas injection
Authors: Commaux N. , Baylor L. R. , Jernigan T. C. , Hollmann E. M. , Humphreys D. A. , Wesley J. C. , Izzo V. A. , Eidietis N. W. , Lasnier C. J. , Moyer R. A. , Parks P. B. , Foust C. R. , Combs S. , Meitner S. J.
Published: October 2014

One of the major challenges that the ITER tokamak will have to face during its operations are disruptions. During the last few years, it has been proven that the global consequences of a disruption can be mitigated by the injection of large quantities of impurities. But one aspect that has been difficult to study was the possibility of local effects inside the torus during such injection that could damage a portion of the device despite the global heat losses and generated currents remaining below design parameter. 3D MHD simulations show that there is a potential for large toroidal asymmetries of the radiated power during impurity injection due to the interaction between the particle injection plume and a large n = 1 mode. Another aspect of 3D effects is the potential occurrence of Vertical Displacement Events (VDE), which could induce large poloidal heat load asymmetries. This potential deleterious effect of 3D phenomena has been studied on the DIII-D tokamak, thanks to the implementation of a multi-location massive gas injection (MGI) system as well as new diagnostic capabilities. This study showed the existence of a correlation between the location of the n = 1 mode and the local heat load on the plasma facing components but shows also that this effect is much smaller than anticipated (peaking factor of ∼1.1 vs 3-4 according to the simulations). There seems to be no observable heat load on the first wall of DIII-D at the location of the impurity injection port as well as no significant radiation asymmetries whether one or 2 valves are fired. This study enabled the first attempt of mitigation of a VDE using impurity injection at different poloidal locations. The results showed a more favorable heat deposition when the VDE is mitigated early (right at the onset) by impurity injection. No significant improvement of the heat load mitigation efficiency has been observed for late particle injection whether the injection is done “in the way” of the VDE (upward VDE mitigated by injection from the upper part of the vessel vs the lower part) or not.
Effect of dielectric wall temperature on plasma plume in an argon atmospheric pressure discharge
Authors: Song Jian , Tang Jingfeng , Huo Yuxin , Wei Liqiu , Wang Youyin , Yu Daren
Published: October 2014

In this letter, the effect of the dielectric wall temperature on the length and volume of an atmospheric pressure plasma jet (APPJ) is investigated using a single-electrode configuration driven with an AC power supply. To distinguish the APPJ status from the argon flow rate, the three modes, laminar, transition, and turbulent, are separated. When the dielectric wall is heated, the APPJ length and volume are enhanced. Also, the transition regions remarkably expand over a large range of flow rates. The results indicate that different factors contribute to the expansion of the transition region. The increase in the radial and axial velocities is the main cause of the expansion of the transition region to the low-velocity region. The expansion to the high-velocity region is dominantly induced by a change in the viscosity.
Transition from amplitude to oscillation death in a network of oscillators
Authors: Nandan Mauparna , Hens C. R. , Pal Pinaki , Dana Syamal K.
Published: October 2014

We report a transition from a homogeneous steady state (HSS) to inhomogeneous steady states (IHSSs) in a network of globally coupled identical oscillators. We perturb a synchronized population of oscillators in the network with a few local negative or repulsive mean field links. The whole population splits into two clusters for a certain number of repulsive mean field links and a range of coupling strength. For further increase of the strength of interaction, these clusters collapse into a HSS followed by a transition to IHSSs where all the oscillators populate either of the two stable steady states. We analytically determine the origin of HSS and its transition to IHSS in relation to the number of repulsive mean-field links and the strength of interaction using a reductionism approach to the model network. We verify the results with numerical examples of the paradigmatic Landau-Stuart limit cycle system and the chaotic Rössler oscillator as dynamical nodes. During the transition from HSS to IHSSs, the network follows the Turing type symmetry breaking pitchfork or transcritical bifurcation depending upon the system dynamics.
Design, construction, and testing of solution resistive divider applied in hundreds of kilovolts nanosecond pulse measurement
Authors: Ge Ya-Feng , Li Lee , Liu Yun-Long , Li Mingjia , Kang Qiang
Published: October 2014

The solution resistive divider is often used considering its excellent high-frequency and withstanding voltage characteristics. This paper develops a nanosecond pulse measurement system based on the CuSO4 solution resistive divider, which can be used to measure high voltage impulses with rise time of 50 ns and amplitude of 300 kV. The low-voltage arm of the newly designed solution resistive divider is composed of noninductive metal film resistors. The newly designed resistive divider combines the advantages of the conventional solution resistive divider and metal film resistive divider. The stray parameters of the resistive divider are theoretically calculated and the circuit simulation is studied. Besides, the square wave response characteristics of the resistive divider are studied in the experiments. Considering the effect of frequency on the surge impedance of the cable, a matching cable of the same type with the transmission cable instead of a common matching resistor is used to improve the matching effects. In order to reduce the effects of electromagnetic interference on the measurement results, some shielding measures are taken. The experimental results show that the measurement system has good response characteristics in the practical application.
Hydration properties of natural and synthetic DNA sequences with methylated adenine or cytosine bases in the R.DpnI target and BDNF promoter studied by molecular dynamics simulations
Authors: Shanak Siba , Helms Volkhard
Published: October 2014

Adenine and cytosine methylation are two important epigenetic modifications of DNA sequences at the levels of the genome and transcriptome. To characterize the differential roles of methylating adenine or cytosine with respect to their hydration properties, we performed conventional MD simulations and free energy perturbation calculations for two particular DNA sequences, namely the brain-derived neurotrophic factor (BDNF) promoter and the R.DpnI-bound DNA that are known to undergo methylation of C5-methyl cytosine and N6-methyl adenine, respectively. We found that a single methylated cytosine has a clearly favorable hydration free energy over cytosine since the attached methyl group has a slightly polar character. In contrast, capping the strongly polar N6 of adenine with a methyl group gives a slightly unfavorable contribution to its free energy of solvation. Performing the same demethylation in the context of a DNA double-strand gave quite similar results for the more solvent-accessible cytosine but much more unfavorable results for the rather buried adenine. Interestingly, the same demethylation reactions are far more unfavorable when performed in the context of the opposite (BDNF or R.DpnI target) sequence. This suggests a natural preference for methylation in a specific sequence context. In addition, free energy calculations for demethylating adenine or cytosine in the context of B-DNA vs. Z-DNA suggest that the conformational B-Z transition of DNA transition is rather a property of cytosine methylated sequences but is not preferable for the adenine-methylated sequences investigated here.
Conformers, infrared spectrum, UV-induced photochemistry, and near-IR-induced generation of two rare conformers of matrix-isolated phenylglycine
Authors: Borba Ana , Gómez-Zavaglia Andrea , Fausto Rui
Published: October 2014

The conformational space of α-phenylglycine (PG) have been investigated theoretically at both the DFT/B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of approximation. Seventeen different minima were found on the investigated potential energy surfaces, which are characterized by different dominant intramolecular interactions: type I conformers are stabilized by hydrogen bonds of the type N–H···O=C, type II by a strong O–H···N hydrogen bond, type III by weak N–H···O–H hydrogen bonds, and type IV by a C=O···H–C contact. The calculations indicate also that entropic effects are relevant in determining the equilibrium populations of the conformers of PG in the gas phase, in particular in the case of conformers of type II, where the strong intramolecular O–H···N hydrogen bond considerably diminishes entropy by reducing the conformational mobility of the molecule. In consonance with the relative energies of the conformers and barriers for conformational interconversion, only 3 conformers of PG were observed for the compound isolated in cryogenic Ar, Xe, and N2 matrices: the conformational ground state (ICa), and forms ICc and IITa. All other significantly populated conformers existing in the gas phase prior to deposition convert either to conformer ICa or to conformer ICc during matrix deposition. The experimental observation of ICc had never been achieved hitherto. Narrowband near-IR irradiation of the first overtone of νOH vibrational mode of ICa and ICc in nitrogen matrices (at 6910 and 6930 cm−1, respectively) led to selective generation of two additional conformers of high-energy, ITc and ITa, respectively, which were also observed experimentally for the first time. In addition, these experiments also provided the key information for the detailed vibrational characterization of the 3 conformers initially present in the matrices. On the other hand, UV irradiation (λ = 255 nm) of PG isolated in a xenon matrix revealed that PG undergoes facile photofragmentation through two photochemical pathways that are favored for different initial conformations of the reactant: (a) decarboxylation, leading to CO2 plus benzylamine (the dominant photofragmentation channel in PG cis-COOH conformers ICa and ICc) and (b) decarbonylation, with generation of CO plus benzonitrile, H2O and H2 (prevalent in the case of the trans-COOH conformer, IITa).
The isotropic–nematic phase transition in hard, slightly curved, lens-like particles
Authors: Cinacchi Giorgio , Tani Alessandro
Published: October 2014

Monte Carlo numerical simulations are used to study in detail how the characteristics of the isotropic–nematic phase transition change as infinitely thin hard platelets are bent into shallow lens-like particles. First, this phase transition in the former reference model system is re-examined and more accurately located. Then, it is shown quantitatively that this already quite weak but distinctly first-order phase transition weakens further upon curving the platelets to such an extent that, thanks to the thinness of these particles that does not favor its pre-emptying by a transition to a (partially) positionally ordered phase, an isotropic-nematic tricritical point limit can be arbitrarily closely approached.
High frequency stimulation of cardiac myocytes: A theoretical and computational study
Authors: Weinberg Seth H.
Published: October 2014

High-frequency stimulation (HFS) has recently been identified as a novel approach for terminating life-threatening cardiac arrhythmias. HFS elevates myocyte membrane potential and blocks electrical conduction for the duration of the stimulus. However, low amplitude HFS can induce rapidly firing action potentials, which may reinitiate an arrhythmia. The cellular level mechanisms underlying HFS-induced electrical activity are not well understood. Using a multiscale method, we show that a minimal myocyte model qualitatively reproduces the influence of HFS on cardiac electrical activity. Theoretical analysis and simulations suggest that persistent activation and de-inactivation of ionic currents, in particular a fast inward window current, underlie HFS-induced action potentials and membrane potential elevation, providing hypotheses for future experiments. We derive analytical expressions to describe how HFS modifies ionic current amplitude and gating dynamics. We show how fast inward current parameters influence the parameter regimes for HFS-induced electrical activity, demonstrating how the efficacy of HFS as a therapy for terminating arrhythmias may depend on the presence of pathological conditions or pharmacological treatments. Finally, we demonstrate that HFS terminates cardiac arrhythmias in a one-dimensional ring of cardiac tissue. In this study, we demonstrate a novel approach to characterize the influence of HFS on ionic current gating dynamics, provide new insight into HFS of the myocardium, and suggest mechanisms underlying HFS-induced electrical activity.
Novel scanning electron microscope bulge test technique integrated with loading function
Authors: Li Chuanwei , Liu Zhanwei , Xie Huimin
Published: October 2014

Membranes and film-on-substrate structures are critical elements for some devices in electronics industry and for Micro Electro Mechanical Systems devices. These structures are normally at the scale of micrometer or even nanometer. Thus, the measurement for the mechanical property of these membranes poses a challenge over the conventional measurements at macro-scales. In this study, a novel bulge test method is presented for the evaluation of mechanical property of micro thin membranes. Three aspects are discussed in the study: (a) A novel bulge test with a Scanning Electron Microscope system realizing the function of loading and measuring simultaneously; (b) a simplified Digital Image Correlation method for a height measurement; and (c) an imaging distortion correction by the introduction of a scanning Moiré method. Combined with the above techniques, biaxial modulus as well as Young's modulus of the polyimide film can be determined. Besides, a standard tensile test is conducted as an auxiliary experiment to validate the feasibility of the proposed method.
Subtle spectral effects accompanying the assembly of bacteriochlorophylls into cyclic light harvesting complexes revealed by high-resolution fluorescence spectroscopy
Authors: Rätsep Margus , Pajusalu Mihkel , Linnanto Juha Matti , Freiberg Arvi
Published: October 2014

We have observed that an assembly of the bacteriochloropyll a molecules into B850 and B875 groups of cyclic bacterial light-harvesting complexes LH2 and LH1, respectively, results an almost total loss of the intra-molecular vibronic structure in the fluorescence spectrum, and simultaneously, an essential enhancement of its phonon sideband due to electron-phonon coupling. While the suppression of the vibronic coupling in delocalized (excitonic) molecular systems is predictable, as also confirmed by our model calculations, a boost of the electron-phonon coupling is rather unexpected. The latter phenomenon is explained by exciton self-trapping, promoted by mixing the molecular exciton states with charge transfer states between the adjacent chromophores in the tightly packed B850 and B875 arrangements. Similar, although less dramatic trends were noted for the light-harvesting complexes containing chlorophyll pigments.
The algebra of two dimensional generalized Chebyshev-Koornwinder oscillator
Authors: Borzov V. V. , Damaskinsky E. V.
Published: October 2014

In the previous works of Borzov and Damaskinsky [“Chebyshev-Koornwinder oscillator,” Theor. Math. Phys. 175(3), 765–772 (2013)] and [“Ladder operators for Chebyshev-Koornwinder oscillator,” in Proceedings of the Days on Diffraction, 2013], the authors have defined the oscillator-like system that is associated with the two variable Chebyshev-Koornwinder polynomials. We call this system the generalized Chebyshev-Koornwinder oscillator. In this paper, we study the properties of infinite-dimensional Lie algebra that is analogous to the Heisenberg algebra for the Chebyshev-Koornwinder oscillator. We construct the exact irreducible representation of this algebra in a Hilbert space $\mathcal {H}$H of functions that are defined on a region which is bounded by the Steiner hypocycloid. The functions are square-integrable with respect to the orthogonality measure for the Chebyshev-Koornwinder polynomials and these polynomials form an orthonormalized basis in the space $\mathcal {H}$H. The generalized oscillator which is studied in the work can be considered as the simplest nontrivial example of multiboson quantum system that is composed of three interacting oscillators.
Research Update: Reactively sputtered nanometer-thin ZrN film as a diffusion barrier between Al and boron layers for radiation detector applications
Authors: Golshani Negin , Mohammadi V. , Schellevis H. , Beenakker C. I. M. , Ishihara R.
Published: October 2014

In this paper, optimization of the process flow for PureB detectors is investigated. Diffusion barrier layers between a boron layer and the aluminum interconnect can be used to enhance the performance and visual appearance of radiation detectors. Few nanometers-thin Zirconium Nitride (ZrN) layer deposited by reactive sputtering in a mixture of Ar/N2, is identified as a reliable diffusion barrier with better fabrication process compatibility than others. The barrier properties of this layer have been tested for different boron layers deposited at low and high temperatures with extensive optical microscopy analyses, electron beam induced current, SEM, and electrical measurements. This study demonstrated that spiking behavior of pure Al on Si can be prevented by the thin ZrN layer thus improving the performance of the radiation detectors fabricated using boron layer.
In operando observation system for electrochemical reaction by soft X-ray absorption spectroscopy with potential modulation method
Authors: Nagasaka Masanari , Yuzawa Hayato , Horigome Toshio , Kosugi Nobuhiro
Published: October 2014

In order to investigate local structures of electrolytes in electrochemical reactions under the same scan rate as a typical value 100 mV/s in cyclic voltammetry (CV), we have developed an in operando observation system for electrochemical reactions by soft X-ray absorption spectroscopy (XAS) with a potential modulation method. XAS spectra of electrolytes are measured by using a transmission-type liquid flow cell with built-in electrodes. The electrode potential is swept with a scan rate of 100 mV/s at a fixed photon energy, and soft X-ray absorption coefficients at different potentials are measured at the same time. By repeating the potential modulation at each fixed photon energy, it is possible to measure XAS of electrochemical reaction at the same scan rate as in CV. We have demonstrated successful measurement of the Fe L-edge XAS spectra of aqueous iron sulfate solutions and of the change in valence of Fe ions at different potentials in the Fe redox reaction. The mechanism of these Fe redox processes is discussed by correlating the XAS results with those at different scan rates.
The near-field acoustic levitation of high-mass rotors
Authors: Hong Z. Y. , Lü P. , Geng D. L. , Zhai W. , Yan N. , Wei B.
Published: October 2014

Here we demonstrate that spherical rotors with 40 mm diameter and 0-1 kg mass can be suspended more than tens of micrometers away from an ultrasonically vibrating concave surface by near-field acoustic radiation force. Their rotating speeds exceed 3000 rpm. An acoustic model has been developed to evaluate the near-field acoustic radiation force and the resonant frequencies of levitation system. This technique has potential application in developing acoustic gyroscope.
The effects of applied current on one-dimensional interdiffusion between copper and nickel in spark plasma sintering
Authors: Rudinsky S. , Gauvin R. , Brochu M.
Published: October 2014

Spark plasma sintering (SPS) is a powder metallurgy technique that employs the use of fast sintering kinetics to produce final consolidated components in a matter of minutes. In order to use blended powders in SPS to obtain fully alloyed parts, diffusion during sintering must be understood. An investigation into the effects of current on the diffusion of copper and nickel was performed using SPS. Bulk specimens were used to generate diffusion couples in SPS in alternating orientations with respect to the direction of the current. Control samples were produced using a horizontal insertion vacuum furnace. Experiments were performed at temperatures between 850 °C and 1000 °C for 3 h. Concentration profiles were obtained by the use of both energy-dispersive spectroscopy and a Monte Carlo simulated correction curve. Diffusion coefficients and activation energies were calculated for samples produced by SPS and annealing without current. It was shown that, at temperatures near 0.9 Tm, the application of current in SPS inhibits diffusion between copper and nickel due to the re-orientation of electrons caused by the loss of ferromagnetism in nickel. Activation energy for diffusion is, however, decreased due to the temperature gradients arising from the difference in resistivity between the two species.
Coherent structures in ion temperature gradient turbulence-zonal flow
Authors: Singh Rameswar , Singh R. , Kaw P. , Gürcan Ö. D. , Diamond P. H.
Published: October 2014

Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m = n = 0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.
Spectrometer for X-ray emission experiments at FERMI free-electron-laser
Authors: Poletto L. , Frassetto F. , Miotti P. , Di Cicco A. , Finetti P. , Grazioli C. , Iesari F. , Kivimäki A. , Stagira S. , Coreno M.
Published: October 2014

A portable and compact photon spectrometer to be used for photon in-photon out experiments, in particular x-ray emission spectroscopy, is presented. The instrument operates in the 25–800 eV energy range to cover the full emissions of the FEL1 and FEL2 stages of FERMI. The optical design consists of two interchangeable spherical varied-lined-spaced gratings and a CCD detector. Different input sections can be accommodated, with/without an entrance slit and with/without an additional relay mirror, that allow to mount the spectrometer in different end-stations and at variable distances from the target area both at synchrotron and at free-electron-laser beamlines. The characterization on the Gas Phase beamline at ELETTRA Synchrotron (Italy) is presented.
Effect of phase transition on quantum transport in group-IV two-dimensional U-shape device
Authors: Sadi Mohammad Abdullah , Gupta Gaurav , Liang Gengchiau
Published: October 2014

The effect of phase-transition from the quantum-spin-hall to the band-insulator phase on the transport through a three-terminal U-shape spin-separator has been computationally investigated via non-equilibrium green function formalism. Two-dimensional group-IV elements have been comprehensively appraised as the device material. The device separates the unpolarized current injected at the source-terminal into nearly 100% spin-polarized currents of the opposite polarities at the two drain terminals. The phase-transition activated by the electric-field orthogonal to the device is shown to extensively influence the current magnitude and its spin-polarization, and the effect is stronger for materials with smaller intrinsic spin-orbit coupling. Moreover, the device length and the area under field are shown to critically affect the device characteristics on phase change. It is shown that the same device can be operated as a spin-filter by inducing phase-transition selectively in the channel. The results are important for designing spin-devices from Group-IV monolayers.