bluuebunny/crossref_metadata_2025 huggingface dataset:
An iterative meshfree method for the elliptic monge–ampère equation in 2D
Authors: Liu Zhiyong , He Yinnian
Published: December 2013

The elliptic Monge–Ampère equation is a fully nonlinear partial differential equation, which originated in geometric surface theory and has been widely applied in dynamic meteorology, elasticity, geometric optics, image processing, and others. The numerical solution of the elliptic Monge–Ampère equation has been a subject of increasing interest recently. In this article, we provide an iterative meshfree method for the elliptic Monge–Ampère equation. The nonlinear equation is simplified as series of Poisson equations with the iterative sequence. Then, the Kansa's method is used to solve these linear equations. We prove the convergence of this method. We also present some numerical experiments to demonstrate the theoretical results. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1507–1517 , 2014
In Situ Monitoring of DNA‐Aptavalve Gating Function on Mesoporous Silica Nanoparticles
Authors: Özalp Veli C. , Pinto Alessandro , Nikulina Elizaveta , Chuvilin Andrey , Schäfer Thomas
Published: December 2013

Mesoporous silica nanoparticles have proved to be efficient stimuli‐responsive controlled release systems for drug delivery when functionalized with nanovalves. Nucleic acid aptamers have recently been adapted to function as novel nanovalves, so‐called “aptavalves,” with molecular‐recognition capabilities and target concentration‐dependent actuation in nanopore‐controlled drug delivery and membrane separation systems. The working mechanism of aptavales relies on their structural rearrangement triggered by a specific target molecule. As a consequence, a controlled and concentration‐dependent release of payload occurs rendering this system particularly appealing for therapeutic applications. However, straightforward monitoring techniques are necessary in order to elucidate the function of aptavalves in situ and varying experimental conditions. Here, the structure‐switching mechanical movements of an ATP‐responsive aptavalve on the surface of mesoporous silica are characterized in real‐time and in situ using circular dichroism (CD). The experimental data obtained on the aptavalve actuation are in excellent agreement with the payload release kinetics determined by fluorescence measurements. It is shown that CD serves as a reliable real‐time analysis of the function of aptalvalves, and that the results obtained obey furthermore standard controlled release models. This allows in principle to pre‐determine the release rate of the modified silica particles according to particular application requirements.
Mechanism of pro‐tumorigenic effect of BMP‐6: Neovascularization involving tumor‐associated macrophages and IL‐1α
Authors: Kwon Seok Joo , Lee Geun Taek , Lee Jae‐Ho , Iwakura Yoichiro , Kim Wun‐Jae , Kim Isaac Yi
Published: December 2013

INTRODUCTION

Overexpression of bone morphogenetic protein‐6 (BMP‐6) has been reported in human prostate cancer tissues. Previously we have demonstrated that BMP‐6 enhances prostate cancer growth in mice and not in tissue culture. Herein, we have investigated the mechanism of BMP‐6's pro‐tumorigenic effect in prostate cancer.

METHODS

Tramp C2 murine and LNCaP human prostate cancer cell lines were co‐cultured with RAW 264.7 and THP‐1 cells, respectively. IL‐1α knockout mice were used to confirm the role of BMP‐6/IL‐1α loop in vivo. Lastly, conditional macrophage null mice cd11b‐DTR was used.

RESULTS

The results demonstrated that BMP‐6 induced the expression of IL‐1α in macrophages via a cross‐talk between NF‐κB1 p50 and Smad1. When endothelial cells were treated with conditioned media harvested from macrophages incubated with BMP‐6, tube formation was detected. In the presence of IL‐1α neutralizing antibody, endothelial tube formation was blocked. In vivo, tumor growth and neovascularization decreased significantly when BMP‐6 was expressed in IL‐1α knockout and conditional macrophage‐null mice.

CONCLUSIONS

Prostate cancer‐derived BMP‐6 stimulates tumor‐associated macrophages to produce IL‐1α through a crosstalk between Smad1 and NF‐κB1; IL‐1α, in turn, promotes angiogenesis and prostate cancer growth. Prostate 74:121–133, 2014. © 2013 Wiley Periodicals, Inc.
Protonation states of active‐site lysines of penicillin‐binding protein 6 from Escherichia coli and the mechanistic implications
Authors: Kumarasiri Malika , Zhang Weilie , Shi Qicun , Fisher Jed F. , Mobashery Shahriar
Published: December 2013

The protonation states of the two active‐site lysines (Lys69 and Lys235) of PBP 6 of Escherichia coli were explored to understand the active site chemistry of this enzyme. Each lysine was individually mutated to cysteine, and the resultant two mutant proteins were purified to homogeneity. Each protein was denatured, and its cysteine was chemically modified to produce an S‐aminoethylated cysteine (γ‐thialysine) residue. Following renaturation, the evaluation of the kinetics of the dd‐carboxypeptidase activity of PBP 6 as a function of pH was found consistent with one lysine in its free‐base (Lys69) and the other in the protonated state (Lys235) for optimal catalysis. The experimental estimates for their pKa values were compared with the pKa values calculated computationally, using molecular‐dynamics simulations and a thermodynamic cycle. Study of the γ‐thialysine69 showed that lysine at position 69 influenced the basic limb of catalysis, consistent with the fact that the two lysine side chains are in proximity to each other in the active site. Based on these observations, a reaction sequence for PBP 6 is proposed, wherein protonated Lys235 serves as the electrostatic substrate anchor and Lys69 as the conduit for protons in the course of the acylation and deacylation half‐reactions. Proteins 2014; 82:1348–1358. © 2013 Wiley Periodicals, Inc.
Perspective: Relativistic Hamiltonians
Authors: Liu Wenjian
Published: December 2013

Under the no‐photon approximation, an effective quantum electrodynamics (QED) Hamiltonian can be constructed based solely on charge conjugation symmetry. It serves as the basis not only for the emerging field of “molecular QED” but also for various approximate Hamiltonians, including the standard no‐pair ones. The whole spectrum of relativistic Hamiltonians is hence completed. © 2013 Wiley Periodicals, Inc.
Biocatalytic Polymer Coatings: On‐Demand Drug Synthesis and Localized Therapeutic Effect under Dynamic Cell Culture Conditions
Authors: Fejerskov Betina , Jensen Najah B. S. , Teo Boon M. , Städler Brigitte , Zelikin Alexander N.
Published: December 2013

Biocatalytic surface coatings are prepared herein for localized synthesis of drugs and their on‐demand, site‐specific delivery to adhering cells. This novel approach is based on the incorporation of an enzyme into multilayered polymer coatings to accomplish enzyme‐prodrug therapy (EPT). The build‐up of enzyme‐containing multilayered coatings is characterized and correlations are drawn between the multilayer film assembly conditions and the enzymatic activity of the resulting coatings. Therapeutic effect elicited by the substrate mediated EPT (SMEPT) strategy is investigated using a prodrug for an anticancer agent, SN‐38. The performance of biocatalytic coatings under flow conditions is investigated and it is demonstrated that EPT allows synthesizing the drugs on‐demand, at the time desired and in a controllable amount to suit particular applications. Finally, using cells cultured in sequentially connected flow chambers, it is demonstrated that SMEPT affords a site‐specific drug delivery, that is, exerts a higher therapeutic effect in cells adhering directly to the biocatalytic coatings than in the cells cultured “downstream”. Taken together, these data illustrate biomedical opportunities made possible by engineering tools of EPT into multilayered polymer coatings and present a novel, highly versatile tool for surface mediated drug delivery.
Thicknesses of individual layers of artery wall indicate increased cardiovascular risk in severe pre‐eclampsia
Authors: Akhter T. , Larsson M. , Wikström A. K. , Naessen T.
Published: December 2013

Objective

To assess whether thicknesses of the intima and media in the common carotid artery (CCA) and the intima/media ratio (I/M) indicate an increased cardiovascular risk in non‐pregnant women with a history of previous severe pre‐eclampsia.

Methods

Thicknesses of the CCA intima and media layers were measured using non‐invasive high‐frequency (22 MHz) ultrasound in 42 women with a history of severe pre‐eclampsia and 44 women with previous normal pregnancy.

Results

Women with a history of severe pre‐eclampsia had a thicker CCA intima and a higher I/M than had women with previous normal pregnancy, also after adjustment for mean arterial pressure, body mass index and CCA intima–media thickness (IMT) (all P < 0.0001). CCA‐IMT did not differ significantly between groups. In receiver–operating characteristics curve analysis, intima thickness and I/M clearly discriminated between women with and those without previous pre‐eclampsia (area under the receiver–operating characteristics curve (AUC), 0.98 and 0.93), whereas CCA‐IMT did not (AUC, 0.52).

Conclusions

CCA individual intima and media thicknesses as well as I/M, but not CCA‐IMT, reflect the known increased long-term cardiovascular risk of pre‐eclampsia. Estimation of individual CCA layers using high‐frequency ultrasound appears preferable to measuring CCA‐IMT for investigating arterial effects and the increased cardiovascular risk in women with a history of severe pre‐eclampsia. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
B‐flow ultrasound facilitates visualization of contrast medium during hysterosalpingo‐contrast sonography
Authors: Sladkevicius P. , Zannoni L. , Valentin L.
Published: December 2013

Objective

To assess if B‐flow ultrasound improves visualization of flow of contrast medium in the Fallopian tubes during hysterosalpingo‐contrast sonography (HyCoSy) compared with grayscale ultrasound.

Methods

This prospective observational study included 160 women referred for HyCoSy as part of infertility work‐up between January 2011 and September 2012. In each woman, at the same session, HyCoSy was performed first using saline with air and then using Sonovue®, and for each contrast medium, grayscale ultrasound was first used and then B‐flow ultrasound was used. Flow of contrast was observed in three parts of each tube: intramural, middle and distal.

Results

In 129 (81%) women, flow of Sonovue was observed in the intramural part of both tubes and in the pouch of Douglas when using grayscale ultrasound. In these women, flow of Sonovue was seen in the middle part of 70% of the 258 tubes when using grayscale ultrasound and in 93% when using B‐flow ultrasound; and in the distal part in 81% when using grayscale ultrasound and in 98% when using B‐flow ultrasound. When using air and saline, flow was seen in the intramural part of 90% and 93% of the tubes, in the middle part in 54% and 72%, and in the distal part in 66% and 90%, using grayscale ultrasound and B‐flow ultrasound, respectively.

Conclusion

B‐flow ultrasound facilitates detection of flow of contrast in the middle and distal parts of the tubes at HyCoSy, especially when a mixture of saline and air is used as contrast medium. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd
Global disorders of consciousness
Authors: Bayne Tim , Hohwy Jakob
Published: December 2013

In recent decades there has been a great deal of interest in global disorders of consciousness, such as the vegetative state, the minimally conscious state, and epileptic absence seizures. Global disorders of consciousness pose significant challenges to consciousness science in that the ordinary pretheoretical criteria for the ascription of consciousness are not easily applied in such contexts, and it is often unclear what kinds of conscious states—if any—patients are in. At the same time, global disorders of consciousness also promise to reveal a great deal about the nature of consciousness and the relationship between consciousness and cognitive and behavioral control. WIREs Cogn Sci 2014, 5:129–138. doi: 10.1002/wcs.1270

This article is categorized under:

Philosophy > Consciousness
Document visualization: an overview of current research
Authors: Gan Qihong , Zhu Min , Li Mingzhao , Liang Ting , Cao Yu , Zhou Baoyao
Published: December 2013

As the number of sources and quantity of document information explodes, efficient and intuitive visualization tools are desperately needed to assist users in understanding the contents and features of a document, while discovering hidden information. This overview introduces fundamental concepts of and designs for document visualization, a number of representative methods in the field, and challenges as well as promising directions of future development. The focus is on explaining the rationale and characteristics of representative document visualization methods for each category. A discussion of the limitations of our classification and a comparison of reviewed methods are presented at the end. This overview also aims to point out theoretical and practical challenges in document visualization. WIREs Comput Stat 2014, 6:19–36. doi: 10.1002/wics.1285

This article is categorized under:

Algorithms and Computational Methods > Computer Graphics

Statistical Learning and Exploratory Methods of the Data Sciences > Text Mining
Examining missing data mechanisms via homogeneity of parameters, homogeneity of distributions, and multivariate normality
Authors: Jamshidian Mortaza , Yuan Ke‐Hai
Published: December 2013

This paper reviews various methods of identifying missing data mechanisms. The three well‐known mechanisms of missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR) are considered. A number of tests deem rejection of homogeneity of means and/or covariances (HMC) among observed data patterns as a means to reject MCAR. Utility of these tests as well as their shortcomings are discussed. In particular, examples of MAR and MNAR data with homogeneous means and covariances between their observed data patterns are provided for which tests of HMC fail to reject MCAR. More generally, tests of homogeneity of parameter estimates between various subsets of data are reviewed and their utility as tests of MCAR and MAR (in special cases) is pointed out. Since many tests of MCAR assume multinormality, methods to assess this assumption in the context of incomplete data are reviewed. Tests of homogeneity of distributions among observed data patterns for MCAR are also considered. A new nonparametric test of this type is proposed on the basis of pairwise comparison of marginal distributions. Finally, methods of examining missing data mechanism based on sensitivity analysis including methods that model missing data mechanism based on logistic, probit, and latent variable regression models, as well as methods that do not require modeling of missing data mechanism are reviewed. The paper concludes with some practical comments about the validity and utility of tests of missing data mechanism. WIREs Comput Stat 2014, 6:56–73. doi: 10.1002/wics.1287

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Multivariate Analysis

Applications of Computational Statistics > Psychometrics
Entwicklung metropolitaner Funktionen im polyzentralen deutschen Städtesystem – Raummuster der Konzentration und funktionalen Spezialisierung
Authors: Volgmann Kati
Published: December 2013

The importance of big cities and metropolises is related to the structural change in favor of the service- and knowledge economy and global economic interrelations, which generate strategic locations or nodes with control and management functions. These high-quality functions are concentrated at these nodes, which are distinct from other spatial areas. Subject of the paper is a theoretical systematization and operationalization of such metropolitan functions which based on international urban concepts and the typology of metropolitan functions—decision and control function, innovation and competition function, gateway function and symbolic function. For this purpose a database of 48 indicators is created that refers to localized functional attribute characteristics to determine the degree of Metropolität of all 439 urban counties and functional-analytical metropolitan areas. It is to be analyzed which cities have metropolitan functions, and how these developed with regard to processes of spatial concentration and functional specialization between 1995 and 2010. It is assumed that due to agglomeration economies (e.g. spatial proximity between actors or developmental edge) the “big” metropolitan areas are the winner of the processes of metropolisation.
Economic resilience. The Case Study of Pomorskie Region
Authors: Sagan Iwona , Masik Grzegorz
Published: December 2013

This article aims to identify the resilience of the Pomorskie Region in Poland. The analysed region belongs to a group of European regions where the negative impact of the economic crisis has not been distinctively visible. In a unitary state like Poland the resilience of the region to the crisis results to a high degree from the external macroeconomic factors of the country. However some regional features play an important role in strengthening resilience. We analysed socio-economic structures in the context of their significance for the region’s resilience. Walker’s and Salt’s (Resilience Thinking. Sustaining ecosystems and people in a changing world, 2006) resilience attributes were used as a template for the findings. Although it is difficult to determine the level of a region’s resilience in a situation of ongoing and growing recession, some conclusions may be derived from the analysis. One of the most important factors of the Pomorskie Region’s resilience is the diversity of economic and social structures. The community and its social capital is undoubtedly one of the strongest attributes of the regional resilience. The Pomorskie Region’s richness in ecosystem services also strengthens its resilience significantly. Overlaps in governance are mainly connected with the development of institutional embeddedness. However the current lack of governance on the level of the most dynamically developing metropolitan areas is an impediment to more dynamic development. The post-totalitarian tradition of centralised governance continues to negatively influence the tight feedbacks attribute of resilience.
Investigation into the effects of prenatal alcohol exposure on postnatal spine development and expression of synaptophysin and PSD95 in rat hippocampus
Authors: Elibol‐Can Birsen , Kilic Ertugrul , Yuruker Sinan , Jakubowska‐Dogru Ewa
Published: December 2013

Ethanol is known as a potent teratogen responsible for the fetal alcohol syndrome characterized by cognitive deficits especially pronounced in juveniles but ameliorating in adults. Since the mechanisms of these deficits and following partial recovery are not fully elucidated, the aim of the present study was to investigate the process of synaptogenesis in the hippocampus over the first two months of life in control and fetal‐alcohol rats. Ethanol was delivered to the pregnant dams by intragastric intubation throughout 7–21 gestation days at the daily dose of 6 g/kg generating a mean blood alcohol level of 246.6 ± 40.9 mg/dl on gestation day 20. The spine densities as well as the expression of pre‐ and postsynaptic proteins, synaptophysin (SYP) and PSD‐95 protein, were evaluated for three distinct hippocampal regions: CA1, CA2+3, and DG and four postnatal days: PD1, PD10, PD30 and PD60, independently. Our results confirmed an intensive synaptogenesis within the brain spurt period (first 10 postnatal days), however, the temporal pattern of changes in the SYP and PSD‐95 expression was different. The ethanol exposure during half of the 1st and the whole 2nd human trimester equivalent resulted in an overall trend toward lower values of synaptic indices at PD1 with a fast recovery from these deficits observed already at PD10. At PD30, around the age when the most pronounced behavioral deficits have been previously reported in juvenile fetal‐alcohol subjects, no significant changes were found in either the hippocampal levels of synaptic proteins or in the spine density in principal hippocampal neurons.
Developing novel blood‐based biomarkers for Alzheimer's disease
Authors: Snyder Heather M. , Carrillo Maria C. , Grodstein Francine , Henriksen Kim , Jeromin Andreas , Lovestone Simon , Mielke Michelle M. , O'Bryant Sid , Sarasa Manual , Sj⊘gren Magnus , Soares Holly , Teeling Jessica , Trushina Eugenia , Ward Malcolm , West Tim , Bain Lisa J. , Shineman Diana W. , Weiner Michael , Fillit Howard M.
Published: December 2013

Alzheimer's disease is the public health crisis of the 21st century. There is a clear need for a widely available, inexpensive and reliable method to diagnosis Alzheimer's disease in the earliest stages, track disease progression, and accelerate clinical development of new therapeutics. One avenue of research being explored is blood based biomarkers. In April 2012, the Alzheimer's Association and the Alzheimer's Drug Discovery Foundation convened top scientists from around the world to discuss the state of blood based biomarker development. This manuscript summarizes the meeting and the resultant discussion, including potential next steps to move this area of research forward.
Update on Evidence‐Based Treatments for Plantar Fasciopathy
Authors: Berbrayer David , Fredericson Michael
Published: December 2013

Plantar fasciopathy, a common, painful condition of the foot, is often diagnosed by a musculoskeletal physiatrist in an outpatient practice setting. This focused review examines the most recent recommendations for the management of plantar fasciopathy in acute, subacute, and chronic phases. The evidence for treatment with various interventions is discussed, and suggestions for clinical care (along with the respective rationales for those therapies) are provided. The purpose of this review is to enable clinicians to make informed evidence‐based decisions about the best available treatments for patients with any phase of plantar fasciopathy. Emerging technologies for the treatment of the condition are also addressed.
Neuropsychologische Verlaufsdiagnostik bei Parkinson-Patienten – Darstellung kritischer Test-Retestdifferenzen für die Einzelfalldiagnostik
Authors: Ringendahl Hubert
Published: December 2013

Zu mehreren von der „Movement Disorder Society Task Force” ( Litvan et al., 2012 ) empfohlenen und weiteren in der Parkinson-Diagnostik bewährten neuropsychologischen Testverfahren werden kritische Test-Retest-Differenzen dargestellt. Diese ermöglichen es, die Wirksamkeit therapeutischer Maßnahmen bzw. den allgemeinen Krankheitsverlauf bzgl. neuropsychologischer Variablen im Einzelfall statistisch zu überprüfen. Da für einige Verfahren die für Berechnung kritischer Test-Retestdifferenzen notwendigen Testdaten fehlen bzw. nur von sehr jungen Probanden vorliegen oder für den deutschen Sprachraum gar nicht vorhanden sind, werden entsprechende Untersuchungen bei Parkinson-Patienten angeregt.
WAIS-IV Profiles in First-Ever Unilateral Ischemic Stroke Patients
Authors: Theiling Johanna , Petermann Franz , Daseking Monika
Published: December 2013

This study aims to identify WAIS-IV profiles in unilateral ischemic stroke patients in rehabilitation (n = 107) compared to matched controls, to determine if patients demonstrate lateralized cognitive impairment, and to investigate whether aphasia has an additional effect on language and working memory subtests. Analyses revealed impairment in performance of stroke patients relative to controls, while effect of left-hemisphere stroke were large on subtests with language and processing speed demands, and of right-hemisphere stroke on subtests with visuo-spatial and processing speed demands. Aphasia had an additional effect on language, working memory and processing speed subtests. Findings confirm the pattern of cognitive deficits found with older versions of the WAIS and suggest that the WAIS-IV detects cognitive deficits in stroke patients.
Die differentielle Validität neuropsychologischer Testverfahren zum Nachweis nicht-authentischer Störungen
Authors: Heubrock Dietmar , Scholl Helena , Petermann Franz
Published: December 2013

Ziel dieser Studie ist es, die Eignung unterschiedlicher neuropsychologischer Verfahren zur Diagnostik von nicht-authentischen Störungen zu ermitteln. Darüber hinaus soll untersucht werden, ob Beschwerdenvalidierungstests (BVT) eine höhere Validität gegenüber anderen neuropsychologischen Verfahren zum Nachweis von nicht authentischen Störungen aufweisen. Dazu wurden 59 Probanden untersucht, die zwischen 2003 bis 2013 forensisch-neuropsychologisch begutachtet wurden. Sie wurden hinsichtlich ihrer Authentizität ihrer neuropsychologischen Beschwerden beurteilt. Neben neuropsychologischen Tests wurden auch BVT eingesetzt. Es zeigte sich, dass die BVT hoch signifikant mit der gutachterlichen Gesamtbeurteilung korrelieren. Zwischen den neuropsychologischen Standardverfahren und der gutachterlichen Gesamtbeurteilung konnten keine signifikanten Zusammenhänge nachgewiesen werden. Es sind demnach nur diejenigen Verfahren, die speziell für den Nachweis von nicht-authentischen Störungen entwickelt worden, dazu geeignet, die Authentizität der Beschwerdenschilderung zu messen.
Einwilligungsfähigkeit bei Demenz: Sensitivität des MMST in einer hypothetischen Einwilligungssituation und spezifische kognitive Korrelate
Authors: Felnhofer Anna , Kothgassner Oswald D. , Kryspin-Exner Ilse
Published: December 2013

Hintergrund: In der Forschung mit Demenz-Patienten ist es entscheidend, mögliche Beeinträchtigungen der Einwilligungsfähigkeit zu ermitteln. Fragestellung: Ziel der Studie war es, zu untersuchen, ob sich der Mini-Mental-Status-Test (MMST) dazu eignet, Beeinträchtigungen der Einwilligungsfähigkeit bei einer hypothetischen Studie vorherzusagen. Methoden: Die Einwilligungsfähigkeit wurde bei 24 Demenz-Patienten und 24 gesunden Gleichaltrigen mit dem MacArthur-Competence-Assessment-Tool (MacCAT) erfasst. Zusätzlich wurden neuropsychologische Korrelate ermittelt. Ergebnisse: Der MMST konnte die Einwilligungsfähigkeit vorhersagen: MMST-Schwellenwerte unter 23 wiesen mit hoher Sicherheit auf eine Einwilligungsunfähigkeit für die hypothetische Studiensituation hin. Gedächtnis und Sprachfunktionen korrelierten hoch mit der Einwilligungsfähigkeit. Schlussfolgerungen: Kognitive Leistung als wesentliche Determinante der Einwilligungsfähigkeit ist stets hinsichtlich einer konkreten Situation zu beurteilen. Studien stimmen überein, dass die Einwilligungsfähigkeit bei MMST-Schwellenwerten unter 23 eingehender untersucht werden sollte.
Zur deutschen Adaptation der Neuropsychological Assessment Battery (NAB)
Authors: Buczylowska Dorota , Bornschlegl Mona , Daseking Monika , Jäncke Lutz , Petermann Franz
Published: December 2013

Standardisierte Testverfahren bilden einen wichtigen Bestandteil neuropsychologischer Diagnostik. Im deutschsprachigen Raum besteht ein großer Bedarf für eine einheitlich normierte neuropsychologische Testbatterie. Die Neuropsychological Assessment Battery (NAB) ist ein in den USA entwickeltes Verfahren zur Beurteilung der neuropsychologischen Funktionen bei Erwachsenen (Alter 18 – 97 Jahre). Die NAB besteht aus zwei äquivalenten Parallelformen, die jeweils in sechs Module untergliedert sind: Screening, Aufmerksamkeit, Sprache, Gedächtnis, Wahrnehmung und Exekutive Funktionen. Das Verfahren ermöglicht eine umfangreiche, psychometrisch fundierte und ökologisch valide Diagnostik. Die NAB wird im Hinblick auf die Entstehungsgeschichte, psychometrische Güte und bisherige Rezeption präsentiert. Die Autorengruppe arbeitet zurzeit an der deutschen Adaptation und Normierung der NAB.
Bacterial foraging optimisation and method of moments for modelling and optimisation of microstrip antennas
Authors: Amir Mounir , Bedra Sami , Benkouda Siham , Fortaki Tarek
Published: December 2013

A novel technique applying bacterial foraging optimisation (BFO) in conjunction with the method of moments (MOM) is developed to calculate accurately the resonant frequency and bandwidth of rectangular microstrip antenna of any dimension and of any substrate thickness. The resonant frequency results obtained by using (BFO/MOM) algorithm are in very good agreement with the experimental results available in the literature. The computation time is greatly reduced as compared with the classical MOM. Furthermore, the idea of this paper can be used for calculating the various parameters of microstrip antennas of different structures and geometries.
Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP)
Authors: Sun L. , Lu W. , Feng Y. C. , Zhang W. H. , Zhang X. Z. , Cao Y. , Zhao Y. Y. , Wu W. , Yang T. J. , Zhao B. , Zhao H. W. , Ma L. Z. , Xia J. W. , Xie D.
Published: December 2013

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R&D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe27+, 236 eμA Xe30+, and 64 eμA Xe35+. Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi30+ and 202 eμA U33+ have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.
Coulomb blockade of spin-dependent shuttling
Authors: Park Hee Chul , Kadigrobov Anatoli M. , Shekhter Robert I. , Jonson M.
Published: December 2013

We show that nanomechanical shuttling of single electrons may enable qualitatively new functionality if spin-polarized electrons are injected into a nanoelectromechanical single-electron tunneling (NEM-SET) device. This is due to the combined effects of spin-dependent electron tunneling and Coulomb blockade of tunneling, which are phenomena that occur in certain magnetic NEM-SET devices. Two effects are predicted to occur in such structures. The first is a reentrant shuttle instability, by which we mean the sequential appearance, disappearance and again the appearance of a shuttle instability as the driving voltage is increased (or the mechanical dissipation is diminished). The second effect is an enhanced spin polarization of the nanomechanically assisted current flow.
Sorption of 4He, H2, Ne, N2, CH4, and Kr impurities in graphene oxide at low temperatures. Quantum effects
Authors: Dolbin A. V. , Esel'son V. B. , Gavrilko V. G. , Manzhelii V. G. , Vinnikov N. A. , Basnukaeva R. M. , Danchuk V. V. , Mysko N. S. , Bulakh E. V. , Maser W. K. , Benito A. M.
Published: December 2013

Sorption and the subsequent desorption of 4He, H2, Ne, N2, CH4, and Kr gas impurities by graphene oxide (GO), glucose-reduced GO (RGO-Gl) and hydrazine-reduced GO (RGO–Hz) powders have been investigated in the temperature interval 2–290 K. It has been found that the sorptive capacity of the reduced sample RGO–Hz is three to six times higher than that of GO. The reduction of GO with glucose has only a slight effect on its sorptive properties. The temperature dependences of the diffusion coefficients of the GO, RGO-Gl, and RGO-Hz samples have been obtained using the measured characteristic times of sorption. It is assumed that the temperature dependences of the diffusion coefficients are determined by the competition of the thermally activated and tunneling mechanisms, the tunneling contribution being dominant at low temperatures.
Current states of a doubly connected superconductor with film bridges
Authors: Krevsun A. V. , Gnezdilova L. V. , Koverya V. P. , Bondarenko S. I.
Published: December 2013

Transport current distribution in the branches of a doubly connected superconductor in the form of a thin-film high-inductance circuit with two bridges of different width in the branches was measured. For the transport current lower than the sum of critical currents of the bridges, its distribution was found to exhibit an anomalous behavior upon reaching the critical current of one of the bridges. For a fixed value of the transport current through the circuit higher than the sum of critical currents of the bridges, low-frequency continuous harmonic voltage self-oscillations together with synchronous current self-oscillations appeared in the circuit branches. The mechanism responsible for the onset of the self-oscillations is discussed.
Magnetostrictive and magnetocaloric effects in Mn0.89Cr0.11NiGe
Authors: Sivachenko A. P. , Mityuk V. I. , Kamenev V. I. , Golovchan A. V. , Val’kov V. I. , Gribanov I. F.
Published: December 2013

The results of magnetic measurements and x-ray analysis of the Mn0.89Cr0.11NiGe alloy are presented. It is shown that the temperatures of the first-order paramagnetic structural transition from hexagonal to orthorhombic phase and paramagnetic–ferromagnetic magnetic phase transition in the orthorhombic phase can be aligned by quenching the sample. This alignment results in the change of the magnetic phase transformation order: the initially isostructural phase transition of the second order becomes a magnetostructural transition of the first order (hexagonal paramagnet–orthorhombic ferromagnet). Moreover, the character of the low-temperature ferromagnetic–antiferromagnetic transition observed in magnetic fields below 3.5 T does not change substantially. The mechanisms of the giant anisotropic magnetostrictive (up to 10%) and magnetocaloric (up to 28 J/(kg·K) upon changing the magnetic field from 0 to 5 T) effects are discussed.
Observation of glass-like low-temperature anomalies in the acoustic properties of nanostructured metals
Authors: Natsik V. D. , Vatazhuk E. N. , Pal-Val P. P. , Pal-Val L. N. , Moskalenko V. A.
Published: December 2013

The values and temperature dependences of the dynamic Young's modulus E(T) of two metals (Ti, Zr) in crystalline (CR) and nanostructured (NS) states are measured by the composite vibrator method at a frequency of ω = 5·105 s−1 over temperatures of 2–20 K. The transition from CR (coarse grained polycrystals) to NS (ultra-fine grained polycrystals) is induced by severe plastic deformation (SPD). The transition of the metals into the NS state is found to be accompanied by a softening of the modulus by a few percent and by the appearance of a distinctive feature in the ENS(T) curves: a transition from a logarithmic to a power-law dependence with increasing temperature at a crossover temperature Tc ≈ 6–8 K, a behavior typical of the elastic moduli of glasses. Structural distortions in the NS state with atomic disorder properties (a glass subsystem or “phase”) are interpreted in terms of dislocation concepts because of the accumulation of high densities of dislocations in metals with random configurations of the dislocation lines induced by SPD. In an appendix the dynamic properties of the dislocation lines fragments are compared, and an analogy established, with the dynamics of quasi-local excitations in glasses (so-called two-level tunnel systems and harmonic oscillators), which are invoked in the theory of glasses to describe their low-temperature properties.
Vibrational spectra of adenine molecules in Kr, Ar, and Ne matrices
Authors: Ivanov A. Yu.
Published: December 2013

IR Fourier spectra of adenine molecules isolated in low-temperature Kr, Ar, and Ne matrices are obtained over the frequency range of 3800–450 cm−1 with a resolution of 0.25 cm−1. MP2 and DFT/BeLYP quantum-mechanical calculations are used to determine the populations of the main structural isomers of adenine for different evaporation temperatures. It is found that the populations of the minor isomers of adenine do not exceed the observation threshold of 0.2% at an evaporation temperature of 450 K. The effect of the matrices reduces to splitting most of the absorption bands of the main isomer A_9H. Splitting of a number of deformation vibration bands owing to Fermi resonances is observed in the 1700–450 cm−1 range. DFT/B3LYP calculations with a polynomial correction for the frequencies of the vibrational spectra are used to determine the spectral ranges within which it is best to search for the most intense vibrations of the rare isomers: 3440–3310, 1710–1680, and 1580–1540 cm−1. It is found that a triple Fermi resonance occurs for γN9H out-of-plane vibrations with participation of librational modes.
The features of ac magnetic susceptibility in thin superconducting films with a high critical current
Authors: Chornomorets M. P. , Kovalchuk D. G.
Published: December 2013

The features of ac magnetic susceptibility appearing in thin superconducting films with a high critical current were investigated for the first time. These features were found in some films of YBa2Cu3O7–δ in magnetic-field and temperature dependencies of the ac susceptibility in the form of Z-like step for the real component, χm′(H) or χm′(T), and V-like dip for the imaginary component, χm″(H) or χm″(T), where the index m indicates measurements at a maximum of the polar diagram χ′′(χ′) (“maximum of losses”). Out of the maximum of losses the effect is also observed and its value depends on the depth of entrance and exit of vortices. It is suggested that the effect is caused by dependencies of the critical current and flux creep on a magnetic field. The magnetic susceptibility for a thin disk was calculated approximately using modified Clem-Sanchez formulas, in which a dependence of the critical current density on the applied field, jc(H), was introduced. The calculations based on the real dependence jc(H) in the films studied and with a simplest account for the flux creep allowed to obtain the dependencies χm′(H) and χm″(H), qualitatively similar to experimental, including the Z- and V-features at a large critical current. It is shown that for these samples the Clem-Sanchez relations between the critical current density, on the one hand, and components of the ac magnetic susceptibility and also the amplitude of the ac field at the maximum of losses, on the other hand, are violated.
Hyperfine magnetic interactions in iron antimonide on 57Fe, 121Sb, and 119Sn
Authors: Thomas M. F. , Tkachenko T. M.
Published: December 2013

The Mössbauer spectroscopy on iron, antimony, and tin isotopes was applied to study the hyperfine magnetic interactions in the iron antimonide Fe1.22Sb of a B8-type crystal structure. The values of effective magnetic fields in the temperature range 10–150 K were calculated for the iron atoms at structurally nonequivalent positions. It was shown that antimony in Fe1.22Sb is not involved into magnetic interactions at T = 77 K in contrast to tin introduced into the compound as a Mössbauer probe.
On the theory of spatially inhomogeneous Bose-Einstein condensation of magnons in yttrium iron garnet
Authors: Bugrij A. I. , Loktev V. M.
Published: December 2013

The Bose-Einstein condensation (BEC) of magnons created by a strong pumping in ferromagnetic thin films of yttrium iron garnet used as systems of finite size is considered analytically. Such a peculiarity, typical for this magnetic material, as the presence of a minimum in the spectrum of spin waves at a finite value of the wave vector is taken into account. The definition of high-temperature BEC is introduced and its characteristics are discussed. A role of boundary conditions for spin variables is analyzed, and it is shown that in the case of free spins on the boundary the magnon lattice can form in the system. The factors responsible for its appearance are discussed
State-to-state, multi-collision, energy transfer in H–H2 gas ensembles
Authors: McCaffery Anthony J. , Marsh Richard J.
Published: December 2013

We use our recently developed computational model of energy flow in gas ensembles to study translation-to-internal energy conversion in an ensemble consisting of H2(0; 0) in a bath of H atoms. This mixture is found in plasmas of industrial importance and also in interstellar clouds. The storage of energy of relative motion as rovibrational energy of H2 represents a potential mechanism for cooling translation. This may have relevance in astrophysical contexts such as the post-recombination epoch of the early universe when hydrogenic species dominated and cooling was a precondition for the formation of structured objects. We find that conversion of translational motion to H2 vibration and rotation is fast and, in our closed system, is complete within around 100 cycles of ensemble collisions. Large amounts of energy become stored as H2 vibration and a tentative mechanism for this unequal energy distribution is suggested. The “structured dis-equilibrium” we observe is found to persist through many collision cycles. In contrast to the rapidity of excitation, the relaxation of H2(6; 10) in H is very slow and not complete after 105 collision cycles. The quasi-equilibrium modal temperatures of translation, rotation, and vibration are found to scale linearly with collision energy but at different rates. This may be useful in estimating the partitioning of energy within a given H + H2 ensemble.
Effect of the exchange bias on the magnetization hysteresis of a ferromagnetic film in contact with an antiferromagnet
Authors: Grechnev A. G. , Kovalev A. S. , Pankratova M. L.
Published: December 2013

The transformation of the hysteretic field dependence of the magnetization of a ferromagnetic thin layer in contact with a magnetically hard antiferromagnet is considered. It is shown that this interaction leads to a shift of the hysteresis loop from the configuration symmetric with respect to magnetic field (exchange bias). Furthermore, upon increasing the magnitude of the exchange interaction, within a narrow range of the magnitudes, there occurs a qualitative change in the hysteresis loop shape and its subsequent disappearance; hence the field dependence of the magnetization becomes monotonous and single-valued.
Open-loop control of noise amplification in a separated boundary layer flow
Authors: Boujo E. , Ehrenstein U. , Gallaire F.
Published: December 2013

Linear optimal gains are computed for the subcritical two-dimensional separated boundary-layer flow past a bump. Very large optimal gain values are found, making it possible for small-amplitude noise to be strongly amplified and to destabilize the flow. The optimal forcing is located close to the summit of the bump, while the optimal response is the largest in the shear layer. The largest amplification occurs at frequencies corresponding to eigenvalues which first become unstable at higher Reynolds number. Nonlinear direct numerical simulations show that a low level of noise is indeed sufficient to trigger random flow unsteadiness, characterized here by large-scale vortex shedding. Next, a variational technique is used to compute efficiently the sensitivity of optimal gains to steady control (through source of momentum in the flow, or blowing/suction at the wall). A systematic analysis at several frequencies identifies the bump summit as the most sensitive region for control with wall actuation. Based on these results, a simple open-loop control strategy is designed, with steady wall suction at the bump summit. Linear calculations on controlled base flows confirm that optimal gains can be drastically reduced at all frequencies. Nonlinear direct numerical simulations also show that this control allows the flow to withstand a higher level of stochastic noise without becoming nonlinearly unstable, thereby postponing bypass transition. In the supercritical regime, sensitivity analysis of eigenvalues supports the choice of this control design. Full restabilization of the flow is obtained, as evidenced by direct numerical simulations and linear stability analysis.
Discharge source coupled to a deceleration unit for anion beam generation: Application to H2− photodetachment
Authors: Rudnev V. , Ureña A. González
Published: December 2013

A cathode discharge source coupled to a deceleration unit for anion beam generation is described. The discharge source, made of stainless steel or duralumin electrodes and Macor insulators, is attached to the exit nozzle valve plate at one end, and to an Einzel lens to the other end. Subsequently, a cylindrical retardation unit is attached to the Einzel lens to decelerate the ions in order to optimize the laser beam interaction time required for spectroscopic investigations. The compact device is able to produce beam intensities of the order of 2 × 1012 anions/cm2 s and 20 μrad of angular divergence with kinetic energies ranging from 30 to 120 eV. Using distinct gas mixtures for the supersonic expansion together with a linear time-of-flight spectrometer, anions of great relevance in molecular astrophysics like, for example, H2−, C3H−, C2−, C2H−, HCN2−, CO2−, CO2H−, C4−, C4H−, C5H4−, C5H6−, C7N−, and C10N− were produced. Finally, in order to demonstrate the capability of the experimental technique the photodetachment cross-section of the metastable H2−, predominantly in the (v = 0, J = 26) state, was measured following laser excitation at λexc = 565 nm obtaining a value of σph = 0.04 Å. To the best of our knowledge, it is the first time that this anion cross-section has been measured.
Optical and carrier transport properties of graphene oxide based crystalline-Si/organic Schottky junction solar cells
Authors: Khatri I. , Tang Z. , Hiate T. , Liu Q. , Ishikawa R. , Ueno K. , Shirai H.
Published: December 2013

We investigated the graphene oxide (GO) based n-type crystalline silicon (c-Si)/conductive poly(ethylene dioxythiophene):poly(styrenesulfonate)(PEDOT:PSS) Schottky junction devices with optical characterization and carrier transport measurement techniques. The optical transmittance in the UV region decreased markedly for the films with increasing the concentration of GO whereas it increased markedly in the visible-infrared regions. Spectroscopic ellipsometry revealed that the ordinary and extraordinary index of refraction increased with increasing the concentration of GO. The hole mobility also increased from 1.14 for pristine film to 1.85 cm2/V s for the 12–15 wt. % GO modified film with no significant increases of carrier concentration. The highest conductivity was found for a 15 wt. % GO modified PEDOT:PSS film: the c-Si/PEDOT:PSS:GO device using this sample exhibited a relatively high power conversion efficiency of 11.04%. In addition, the insertion of a 2–3 nm-thick GO thin layer at the c-Si/PEDOT:PSS interface suppressed the carrier recombination efficiency of dark electron and photo-generated hole at the anode, resulting in the increased photovoltaic performance. This study indicates that the GO can be good candidates for hole transporting layer of c-Si/PEDOT:PSS Schottky junction solar cell.

This article is being retracted effective 18 December 2014.
Screening magnetic fields by superconductors: A simple model
Authors: Caputo J.-G. , Gozzelino L. , Laviano F. , Ghigo G. , Gerbaldo R. , Noudem J. , Thimont Y. , Bernstein P.
Published: December 2013

We introduce a simple approach to evaluate the magnetic field distribution around superconducting samples, based on the London equations; the elementary variable is the vector potential. This procedure has no adjustable parameters, only the sample geometry and the London length, λ, determine the solution. This approach was validated by comparing the induction field calculated to the one measured above MgB2 disks of different diameters, at 20 K and for applied fields lower than 0.4 T. The model can be applied if the flux line penetration inside the sample can be neglected when calculating the induction field distribution outside the superconductor. We conclude by showing on a cup-shape geometry how one can design a magnetic shield satisfying a specific constraint.