bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of anchoring in the phase behaviour of discotic liquid crystals
Authors: Salgado-Blanco Daniel , Mendoza Carlos I. , Chávez-Rojo Marco A. , Moreno-Razo José A. , Díaz-Herrera Enrique
Published: March 2018

Molecular dynamics simulations were performed for a Gay-Berne discotic fluid confined in a slab geometry for two different anchorings: homeotropic (face-on) and planar (edge-on), and for two different confinement lengths.
On the chemistry and electrochemistry of LiPON breakdown
Authors: Put Brecht , Vereecken Philippe M. , Stesmans Andre
Published: March 2018

Electrolyte stability remains one of the key hurdles for the increasing the battery output potential. In the present work, we determine the electrochemical stability of LiPON both experimentally and based on thermodynamic considerations. Different breakdown modes are suggested depending on bias polarity.
Paper spray ionization mass spectrometry allied to chemometric tools for quantification of whisky adulteration with additions of sugarcane spirit
Authors: Tosato Flávia , Correia Radigya M. , Oliveira Bruno G. , Fontes André M. , França Hildegardo S. , Coltro Wendell K. T. , Filgueiras Paulo R. , Romão Wanderson
Published: March 2018

Whisky is one of the most commercialized distilled beverages in the world.
An optimal trapdoor zeolite for exclusive admission of CO2 at industrial carbon capture operating temperatures
Authors: Du Tao , Fang Xin , Liu Liying , Shang Jin , Zhang Bin , Wei Yichao , Gong He , Rahman Shamsur , May Eric F. , Webley Paul A. , Li Gang (Kevin)
Published: March 2018

Molecular trapdoor chabazites with lowered Si/Al ratios show elevated operating temperatures for carbon capture and significantly improved separation power.
The time-resolved fluorescence study of kinetics and thermodynamics of Eu(iii) and Tb(iii) complexes with the DO2A macrocyclic ligand
Authors: Smrčka Filip , Lubal Přemysl
Published: March 2018

The thermodynamics and kinetics of formation/dissociation of Eu(iii) and Tb(iii) with the H2DO2A macrocyclic ligand were studied by time-resolved fluorescence spectroscopy.
A promising bulky anion based lithium borate salt for lithium metal batteries
Authors: Qiao Lixin , Cui Zili , Chen Bingbing , Xu Gaojie , Zhang Zhonghua , Ma Jun , Du Huiping , Liu Xiaochen , Huang Suqi , Tang Kun , Dong Shanmu , Zhou Xinhong , Cui Guanglei
Published: March 2018

A promising lithium borate salt for next generation lithium metal batteries.
Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins
Authors: Malgieri Gaetano , D'Abrosca Gianluca , Pirone Luciano , Toto Angelo , Palmieri Maddalena , Russo Luigi , Sciacca Michele Francesco Maria , Tatè Rosarita , Sivo Valeria , Baglivo Ilaria , Majewska Roksana , Coletta Massimo , Pedone Paolo Vincenzo , Isernia Carla , De Stefano Mario , Gianni Stefano , Pedone Emilia Maria , Milardi Danilo , Fattorusso Roberto
Published: March 2018

Understanding the molecular determinants of fibrillogenesis by studying the aggregation propensities of high homologous proteins with different folding pathways.
Development of microfluidic platforms for the synthesis of metal complexes and evaluation of their DNA affinity using online FRET melting assays
Authors: Rakers Viktoria , Cadinu Paolo , Edel Joshua B. , Vilar Ramon
Published: March 2018

Two new microfluidic platforms are reported to synthesize metal complexes and assess their DNA affinity in continuous flow.
The ethical concerns about transgenic crops
Authors: Ricroch Agnès E. , Guillaume-Hofnung Michèle , Kuntz Marcel
Published: March 2018

It is generally accepted that transgenesis can improve our knowledge of natural processes, but also leads to agricultural, industrial or socio-economical changes which could affect human society at large and which may, consequently, require regulation. It is often stated that developing countries are most likely to benefit from plant biotechnology and are at the same time most likely to be affected by the deployment of such new technologies. Therefore, ethical questions related to such biotechnology probably also need to be addressed. We first illustrate how consequentialist and nonconsequentialist theories of ethics can be applied to the genetically modified organism debate, namely consequentialism, autonomy/consent ethics (i.e. self-determination of people regarding matters that may have an effect on these people) and virtue ethics (i.e. whether an action is in adequacy with ideal traits). We show that these approaches lead to highly conflicting views. We have then refocused on moral ‘imperatives', such as freedom, justice and truth. Doing so does not resolve all conflicting views, but allows a gain in clarity in the sense that the ethical concerns are shifted from a technology (and its use) to the morality or amorality of various stakeholders of this debate.
More Than a Story: My Life Came Back to Life
Authors: Strong Katie A. , Lagerwey Mary D. , Shadden Barbara B.
Published: March 2018

Purpose

Social models of aphasia rehabilitation emphasize the importance of supporting identity renegotiation, which can be accomplished in part through personal narrative construction. The purpose of this study was to examine the experiences of persons who had engaged in a project to coconstruct personal narratives about life with aphasia.

Method

Qualitative interviews were conducted with 3 participants with aphasia who completed a 4-week personal narrative coconstruction project, which included preadministration and postadministration of the Communication Confidence Rating Scale for Aphasia (Cherney & Babbitt, 2011). Results were analyzed using interpretative phenomenological analysis.

Results

Three themes were revealed: (a)More than a story: It changed my lifevalidated the idea that the narrative coconstruction process supported a positive view of identity; (b)A positive experiencecaptured the participants' enjoyment in coconstructing and sharing their story; (c)Hopeengendered by the coconstruction experience empowered participants with new levels of confidence not only in their communication skills but also in themselves.

Conclusions

This study provided insight into the experience of coconstructing personal narratives using a structured protocol. Participants experienced the project as a positive, meaningful opportunity to actively contemplate their life and look forward. The study has implications for clinicians considering support of identity renegotiation in aphasia rehabilitation.
Response Time Inconsistencies in Object and Action Naming in Anomic Aphasia
Authors: Galletta Elizabeth E. , Goral Mira
Published: March 2018

Purpose

The effect of repeated naming on both object and action picture naming in individuals with anomic aphasia is explored. We asked whether repeatedly naming the same items leads to improved accuracy and reduced response latency.

Method

Ten individuals with anomic aphasia and 6 healthy adults, 3 young and 3 old, named a set of 27 object pictures and a set of 27 action pictures presented 1 at a time on a computer screen. We examined accuracy and response times (RTs) across the 2 blocks of 10 repeated trials.

Results

Results demonstrated higher accuracy and faster RTs for object than for action naming for all participants, with lower accuracy rates and slower RTs for the people with aphasia (PWA) compared with the healthy individuals, and diverging patterns of change across trials. Unlike the healthy participants, whose RTs decreased across trials, PWA continued to demonstrate variability in response latencies across the trials.

Conclusions

Our preliminary results suggest that measuring RT may be useful in characterizing retrieval difficulty in anomic aphasia and that the retrieval processes in PWA, even in those who experience mild anomia, may be less efficient or different from those processes in neurologically healthy individuals.
Links Between Short-Term Memory and Word Retrieval in Aphasia
Authors: Minkina Irene , Martin Nadine , Spencer Kristie A. , Kendall Diane L.
Published: March 2018

Purpose

This study explored the relationship between anomia and verbal short-term memory (STM) in the context of an interactive activation language processing model.

Method

Twenty-four individuals with aphasia and reduced STM spans (i.e., impaired immediate serial recall of words) completed a picture-naming task and a word pair repetition task (a measure of verbal STM). Correlations between verbal STM and word retrieval errors made on the picture-naming task were examined.

Results

A significant positive correlation between naming accuracy and verbal span length was found. More intricate verbal STM analyses examined the relationship between picture-naming error types (i.e., semantic vs. phonological) and 2 measures of verbal STM: (a) location of errors on the word pair repetition task and (b) imageability and frequency effects on the word pair repetition task. Results indicated that, as phonological word retrieval errors (relative to semantic) increase, bias toward correct repetition of high-imageability words increases.

Conclusions

Results suggest that word retrieval and verbal STM tasks likely rely on a partially shared temporary linguistic activation process.
Exploring Treatment Fidelity in Persons With Aphasia Autonomously Practicing With Computerized Therapy Materials
Authors: Ball Angel L. , de Riesthal Michael , Steele Richard D.
Published: March 2018

Purpose

Current computer technologies permit independent practice for people with cognitive–communicative disorders. Previous research has investigated compliance rates and outcome changes but not treatment fidelity per se during practice. Our aim was to examine adherence to procedures (treatment fidelity) and accuracy while persons with aphasia independently practiced word production using interactive, multimodal, user-controlled, word-level icons on computers.

Method

Four persons with aphasia independently practiced single-word production after stimulation via user-initiated interactions in 3 conditions: (I) auditory stimulus with static representational drawing; (II) auditory stimulus with synchronized articulation video; and (III) users' choice between the 2 prior conditions. Sessions were video-recorded for subsequent analysis, which established emergently refined behavioral taxonomies using an iterative, mixed-methods approach.

Results

In independent practice, users only sometimes adhere to modeled behaviors, other times improvising novel behaviors. The latter sometimes co-occurred with successful productions. Differences in success rates were noted between Conditions I and II across behaviors with Condition II generally favored. In Condition III, participants tended to choose the stimulus that resulted in highest success rates.

Conclusions

During independent practice with technology, persons with aphasia do not necessarily comply with clinicians' practice instructions, and treatment fidelity does not determine success. Autonomy and choice in practice may reveal unanticipated dimensions for computerized aphasia treatment.
Describing Phonological Paraphasias in Three Variants of Primary Progressive Aphasia
Authors: Dalton Sarah Grace Hudspeth , Shultz Christine , Henry Maya L. , Hillis Argye E. , Richardson Jessica D.
Published: March 2018

Purpose

The purpose of this study was to describe the linguistic environment of phonological paraphasias in 3 variants of primary progressive aphasia (semantic, logopenic, and nonfluent) and to describe the profiles of paraphasia production for each of these variants.

Method

Discourse samples of 26 individuals diagnosed with primary progressive aphasia were investigated for phonological paraphasias using the criteria established for the Philadelphia Naming Test (Moss Rehabilitation Research Institute, 2013). Phonological paraphasias were coded for paraphasia type, part of speech of the target word, target word frequency, type of segment in error, word position of consonant errors, type of error, and degree of change in consonant errors.

Results

Eighteen individuals across the 3 variants produced phonological paraphasias. Most paraphasias were nonword, followed by formal, and then mixed, with errors primarily occurring on nouns and verbs, with relatively few on function words. Most errors were substitutions, followed by addition and deletion errors, and few sequencing errors. Errors were evenly distributed across vowels, consonant singletons, and clusters, with more errors occurring in initial and medial positions of words than in the final position of words. Most consonant errors consisted of only a single-feature change, with few 2- or 3-feature changes. Importantly, paraphasia productions by variant differed from these aggregate results, with unique production patterns for each variant.

Conclusions

These results suggest that a system where paraphasias are coded as present versus absent may be insufficient to adequately distinguish between the 3 subtypes of PPA. The 3 variants demonstrate patterns that may be used to improve phenotyping and diagnostic sensitivity. These results should be integrated with recent findings on phonological processing and speech rate. Future research should attempt to replicate these results in a larger sample of participants with longer speech samples and varied elicitation tasks.

Supplemental Materials

https://doi.org/10.23641/asha.5558107
The Relationship Between Confrontation Naming and Story Gist Production in Aphasia
Authors: Richardson Jessica D. , Hudspeth Dalton Sarah Grace , Fromm Davida , Forbes Margaret , Holland Audrey , MacWhinney Brian
Published: March 2018

Purpose

The purpose of this study was to examine the relationship between picture naming performance and the ability to communicate the gist, or essential elements, of a story. We also sought to determine if this relationship varied according to Western Aphasia Battery–Revised (WAB-R; Kertesz, 2007) aphasia subtype.

Method

Demographic information, test scores, and transcripts of 258 individuals with aphasia completing 3 narrative tasks were retrieved from the AphasiaBank database. Narratives were subjected to a main concept analysis to determine gist production. A correlation analysis was used to investigate the relationship between naming scores and main concept production for the whole group of persons with aphasia and for WAB-R subtypes separately.

Results

We found strong correlations between naming test scores and narrative gist production for the large sample of persons with aphasia. However, the strength of the correlations varied by WAB-R subtype.

Conclusions

Picture naming may accurately predict gist production for individuals with Broca's and Wernicke's aphasia, but not for other WAB-R subtypes. Given the current reprioritization of outcome measurement, picture naming may not be an appropriate surrogate measure for functional communication for all persons with aphasia.

Supplemental Materials

https://doi.org/10.23641/asha.5851848
Outgassing on stagnant-lid super-Earths
Authors: Dorn C. , Noack L. , Rozel A. B.
Published: March 2018

Aims. We explore volcanic CO2-outgassing on purely rocky, stagnant-lid exoplanets of different interior structures, compositions, thermal states, and age. We focus on planets in the mass range of 1–8 M⊕ (Earth masses). We derive scaling laws to quantify first- and second-order influences of these parameters on volcanic outgassing after 4.5 Gyr of evolution.

Methods. Given commonly observed astrophysical data of super-Earths, we identify a range of possible interior structures and compositions by employing Bayesian inference modeling. The astrophysical data comprise mass, radius, and bulk compositional constraints; ratios of refractory element abundances are assumed to be similar to stellar ratios. The identified interiors are subsequently used as input for two-dimensional (2D) convection models to study partial melting, depletion, and outgassing rates of CO2.

Results. In total, we model depletion and outgassing for an extensive set of more than 2300 different super-Earth cases. We find that there is a mass range for which outgassing is most efficient (~2–3 M⊕, depending on thermal state) and an upper mass where outgassing becomes very inefficient (~5–7 M⊕, depending on thermal state). At small masses (below 2–3 M⊕) outgassing positively correlates with planet mass, since it is controlled by mantle volume. At higher masses (above 2–3 M⊕), outgassing decreases with planet mass, which is due to the increasing pressure gradient that limits melting to shallower depths. In summary, depletion and outgassing are mainly influenced by planet mass and thermal state. Interior structure and composition only moderately affect outgassing rates. The majority of outgassing occurs before 4.5 Gyr, especially for planets below 3 M⊕.

Conclusions. We conclude that for stagnant-lid planets, (1) compositional and structural properties have secondary influence on outgassing compared to planet mass and thermal state, and (2) confirm that there is a mass range for which outgassing is most efficient and an upper mass limit, above which no significant outgassing can occur. Our predicted trend of CO2-atmospheric masses can be observationally tested for exoplanets. These findings and our provided scaling laws are an important step in order to provide interpretative means for upcoming missions such as JWST and E-ELT, that aim at characterizing exoplanet atmospheres.
Environmental warming induces behavioral and metabolic changes in a freshwater crustacean − aeglids as a model organism
Authors: Cogo Gláucia Bolzan , Biasi Cristiane , Severo Eduardo Stringini , Loro Vania , Santos Sandro
Published: March 2018

Ecological processes in small-order streams are dependent on their community. A threat to the appropriate functioning of these processes is the water warming of streams since changes in temperature can modify the behavior, abundance, and distribution of the species. A way to predict the consequences of global warming on ecological processes in these ecosystems is to study their aquatic community. Here we evaluated behavioral and metabolic changes inAegla longirostriat different temperatures (21 °C and 24 °C). Experiments were performed in laboratory conditions. We calculated leaf consumption and quantified glycogen, protein and amino acid composition in the hepatopancreas. We also conducted a behavioral test to investigate the activity level of aeglids. Leaf consumption did not differ between temperatures. However, the amount of protein was higher at 21 °C, and the amino acid and glycogen levels were greater at 24 °C. In the present study we evaluated only the activity of hepatopancreas, so we can assume that the organ may have used glucose through the breakdown of glycogen and also performing some protein break. However, this hypothesis needs to be confirmed by checking for muscle activity. Animals kept at 24 °C showed a lower level of activity. This strategy possibly occurs to save energy, as in elevated temperature crustaceans spend extra energy to maintain their homeostasis. This study indicates that a future increase temperature of streams will impact the populations of aeglids by changing their metabolism and behavior.
Uniform in time error analysis of HDG approximation for Schrödinger equation based on HDG projection
Authors: Xiong Chunguang , Luo Fusheng , Ma Xiuling
Published: March 2018

This paper presents error analysis of hybridizable discontinuous Galerkin (HDG) time-domain method for solving time dependent Schrödinger equations. The numerical trace and numerical flux are constructed to preserve the conservative property for the density of the particle described. We prove that there exist the superconvergence properties of the HDG method, which do hold for second-order elliptic problems, uniformly in time for the semidiscretization by the same method of Schrödinger equations provided that enough regularity is satisfied. Thus, if the approximations are piecewise polynomials of degreer, the approximations to the wave function and the flux converge with orderr+ 1. The suitably chosen projection of the wave function into a space of lower polynomial degree superconverges with orderr+ 2 forr≥ 1 uniformly in time. The application of element-by-element postprocessing of the approximate solution which provides an approximation of the potential convergence with orderr+ 2 forr≥ 1 inL2is also uniformly in time.
Total variation regularization of multi-material topology optimization
Authors: Clason Christian , Kruse Florian , Kunisch Karl
Published: March 2018

This work is concerned with the determination of the diffusion coefficient from distributed data of the state. This problem is related to homogenization theory on the one hand and to regularization theory on the other hand. An approach is proposed which involves total variation regularization combined with a suitably chosen cost functional that promotes the diffusion coefficient assuming prespecified values at each point of the domain. The main difficulty lies in the delicate functional-analytic structure of the resulting nondifferentiable optimization problem with pointwise constraints for functions of bounded variation, which makes the derivation of useful pointwise optimality conditions challenging. To cope with this difficulty, a novel reparametrization technique is introduced. Numerical examples using a regularized semismooth Newton method illustrate the structure of the obtained diffusion coefficient.
Value function and optimal trajectories for a maximum running cost control problem with state constraints. Application to an abort landing problem
Authors: Assellaou Mohamed , Bokanowski Olivier , Desilles Anya , Zidani Hasnaa
Published: March 2018

The aim of this article is to study the Hamilton Jacobi Bellman (HJB) approach for state-constrained control problems with maximum cost. In particular, we are interested in the characterization of the value functions of such problems and the analysis of the associated optimal trajectories, without assuming any controllability assumption. The rigorous theoretical results lead to several trajectory reconstruction procedures for which convergence results are also investigated. An application to a five-state aircraft abort landing problem is then considered, for which several numerical simulations are performed to analyse the relevance of the theoretical approach.
Convergence of a finite volume scheme for a parabolic system with a free boundary modeling concrete carbonation
Authors: Chainais-Hillairet Claire , Merlet Benoît , Zurek Antoine
Published: March 2018

In this paper we define and study a finite volume scheme for a concrete carbonation model proposed by Aiki and Muntean in [Adv. Math. Sci. Appl.19(2009) 109–129]. The model consists in a system of two weakly coupled parabolic equations in a varying domain whose length is governed by an ordinary differential equation. The numerical sheme is obtained by a Euler discretisation in time and a Scharfetter-Gummel discretisation in space. We establish the convergence of the scheme. As a by-product, we obtain existence of a solution to the model. Finally, some numerical experiments show the efficiency of the scheme.
A prioriestimates and optimal finite element approximation of the MHD flow in smooth domains
Authors: He Yinnian , Zou Jun
Published: March 2018

We study a finite element approximation of the initial-boundary value problem of the 3D incompressible magnetohydrodynamic (MHD) system under smooth domains and data. We first establish several important regularities anda prioriestimates for the velocity, pressure and magnetic field (u,p,B) of the MHD system under the assumption that ∇u∈L4(0,T;L2(Ω)3 × 3) and ∇ ×B∈L4(0,T;L2(Ω)3). Then we formulate a finite element approximation of the MHD flow. Finally, we derive the optimal error estimates of the discrete velocity and magnetic field in energy-norm and the discrete pressure inL2-norm, and the optimal error estimates of the discrete velocity and magnetic field inL2-norm by means of a novel negative-norm technique, without the help of the standard duality argument for the Navier-Stokes equations.
A multigrid algorithm for the p-version of the virtual element method
Authors: Antonietti Paola F. , Mascotto Lorenzo , Verani Marco
Published: March 2018

We present a multigrid algorithm for the solution of the linear systems of equations stemming from the p-version of the virtual element discretization of a two-dimensional Poisson problem. The sequence of coarse spaces are constructed decreasing progressively the polynomial approximation degree of the virtual element space, as in standard p-multigrid schemes. The construction of the interspace operators relies on auxiliary virtual element spaces, where it is possible to compute higher order polynomial projectors. We prove that the multigrid scheme is uniformly convergent, provided the number of smoothing steps is chosen sufficiently large. We also demonstrate that the resulting scheme provides a uniform preconditioner with respect to the number of degrees of freedom that can be employed to accelerate the convergence of classical Krylov-based iterative schemes. Numerical experiments validate the theoretical results.
A posteriori snapshot location for POD in optimal control of linear parabolic equations
Authors: Alla Alessandro , Grässle Carmen , Hinze Michael
Published: March 2018

In this paper we study the approximation of an optimal control problem for linear parabolic PDEs with model order reduction based on Proper Orthogonal Decomposition (POD-MOR). POD-MOR is a Galerkin approach where the basis functions are obtained upon information contained in time snapshots of the parabolic PDE related to given input data. In the present work we show that for POD-MOR in optimal control of parabolic equations it is important to have knowledge about the controlled system at the right time instances. We propose to determine the time instances (snapshot locations) by an a posteriori error control concept. The proposed method is based on a reformulation of the optimality system of the underlying optimal control problem as a second order in time and fourth order in space elliptic system which is approximated by a space-time finite element method. Finally, we present numerical tests to illustrate our approach and show the effectiveness of the method in comparison to existing approaches.
Ana posteriorierror analysis for an optimal control problem with point sources
Authors: Allendes Alejandro , Otárola Enrique , Rankin Richard , Salgado Abner J.
Published: March 2018

We propose and analyze a reliable and efficienta posteriorierror estimator for a control-constrained linear-quadratic optimal control problem involving Dirac measures; the control variable corresponds to the amplitude of forces modeled as point sources. The proposeda posteriorierror estimator is defined as the sum of two contributions, which are associated with the state and adjoint equations. The estimator associated with the state equation is based on Muckenhoupt weighted Sobolev spaces, while the one associated with the adjoint is in the maximum norm and allows for unbounded right hand sides. The analysis is valid for two and three-dimensional domains. On the basis of the deviseda posteriorierror estimator, we design a simple adaptive strategy that yields optimal rates of convergence for the numerical examples that we perform.
Sparse quadrature for high-dimensional integration with Gaussian measure
Authors: Chen Peng
Published: March 2018

In this work we analyze the dimension-independent convergence property of an abstract sparse quadrature scheme for numerical integration of functions of high-dimensional parameters with Gaussian measure. Under certain assumptions on the exactness and boundedness of univariate quadrature rules as well as on the regularity assumptions on the parametric functions with respect to the parameters, we prove that the convergence of the sparse quadrature error is independent of the number of the parameter dimensions. Moreover, we propose both an a priori and an a posteriori schemes for the construction of a practical sparse quadrature rule and perform numerical experiments to demonstrate their dimension-independent convergence rates.
Generalized wave propagation problems and discrete exterior calculus
Authors: Räbinä Jukka , Kettunen Lauri , Mönkölä Sanna , Rossi Tuomo
Published: March 2018

We introduce a general class of second-order boundary value problems unifying application areas such as acoustics, electromagnetism, elastodynamics, quantum mechanics, and so on, into a single framework. This also enables us to solve wave propagation problems very efficiently with a single software system. The solution method precisely follows the conservation laws in finite-dimensional systems, whereas the constitutive relations are imposed approximately. We employ discrete exterior calculus for the spatial discretization, use natural crystal structures for three-dimensional meshing, and derive a “discrete Hodge” adapted to harmonic wave. The numerical experiments indicate that the cumulative pollution error can be practically eliminated in the case of harmonic wave problems. The restrictions following from the CFL condition can be bypassed with a local time-stepping scheme. The computational savings are at least one order of magnitude.
Quantitative PET-Bildgebung für die Dosimetrie an Beispielen von 124I, 86Y, 68Ga und 44Sc
Authors: Stebner Vanessa , Hetkamp Philipp , Binse Ina , Jentzen Walter
Published: March 2018

Die prätherapeutische PET-Dosimetrie gewinnt insbesondere in der Radionuklidtherapie zur Behandlung von Krebserkrankungen immer mehr an Bedeutung. Im Vergleich zu anderen bildgebenden Verfahren der Nuklearmedizin ermöglicht sie eine genauere Bestimmung der Energiedosen pro applizierte Therapieaktivität in Tumoren und Risikoorganen. Zum Beispiel werden die Radionuklide 124I, 86Y und 68Ga zur Optimierung der Radiojodtherapie von Schilddrüsenkarzinomen und zur Therapieplanung von Somatostatinrezeptor-positiven Tumoren eingesetzt. Das kürzlich eingeführte PET-Nuklid 44Sc rückt immer mehr in den Fokus als Ersatz für 68Ga, weil es auch Spätmessungen mit ausreichender Bildqualität erlaubt. Zur Abschätzung der Energiedosis ist eine genaue PET-Quantifizierung der räumlichen und zeitlichen Tracer-Aktivitätsverteilung im Tumor bzw. Organ notwendig. Im Vergleich zum Standard-Radionuklid 18F besitzen 124I, 86Y und 44Sc ungünstige Zerfallseigenschaften. Die Quantifizierung ist dadurch beeinträchtigt. Außerdem werden die Aktivitäten von kleinen Tumoren durch den bekannten Partial-Volumen-Effekt beeinflusst. In dieser Arbeit werden die wesentlichen Faktoren zur PET-Quantifizierung beschrieben, die bei der Anwendung von 124I, 86Y, 68Ga und 44Sc bei der prätherapeutischen Dosimetrie zu berücksichtigen sind. Darüber hinaus werden klinische Dosimetrieprotokolle von ausgewählten Arbeiten und ihre Korrekturverfahren kurz präsentiert.
Polysomnographie bei Kindern: nicht nur an obstruktive Schlafapnoe denken
Authors: Sommer J. Ulrich
Published: March 2018

Heubi CH et al. Polysomnography in Pediatric Otolaryngology: If Not Obstructive Sleep Apnea, What Is It?
Otolaryngol Head Neck Surg 2017; 157: 1053–1059

Ärzte der Abteilung für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie der Universität von Cincinnati
überprüften die Polysomnographie- Diagnosen von Kindern mit Verdacht auf schlafbezogene Atmungsstörungen
(SBAS) und obstruktiver Schlafapnoe (OSA).
Adherence to quality indicators and surveillance guidelines in the management of Barrett’s esophagus: a retrospective analysis
Authors: Westerveld Donevan , Khullar Vikas , Mramba Lazarus , Ayoub Fares , Brar Tony , Agarwal Mitali , Forde Justin , Chakraborty Joydeep , Riverso Michael , Perbtani Yaseen , Gupte Anand , Forsmark Chris , Draganov Peter , Yang Dennis
Published: March 2018

Background Adherence to quality indicators and surveillance guidelines in the management of Barrett’s esophagus (BE) promotes high-quality, cost-effective care. The aims of this study were (1) to evaluate adherence to standardized classification (Prague Criteria) and systematic (four-quadrant) biopsy protocol, (2) to identify predictors of practice patterns, and (3) to assess adherence to surveillance guidelines for non-dysplastic BE (NDBE).

Methods This was a single-center retrospective study of esophagogastroduodenoscopy (EGD) performed for BE (June 2008 to December 2015). Patient demographics, procedure characteristics, and histology results were obtained from the procedure report-generating database and chart review. Adherence to Prague Criteria and systematic biopsies was based on operative report documentation. Multiple logistic regression analysis was performed to identify predictors of practice patterns. Guideline adherent surveillance EGD was defined as those performed within 6 months of the recommended 3- to 5-year interval.

Results In total, 397 patients (66.5 % male; mean age 60.1 ± 12.5 years) had an index EGD during the study period. Adherence to Prague Criteria and systematic biopsies was 27.4 % and 24.1 %, respectively. Endoscopists who performed therapeutic interventions for BE were more likely to use the Prague Criteria (OR: 3.16; 95 %CI: 1.47 – 6.82; P < 0.01) than those who did not. Longer time in practice was positively associated with adherence to Prague Criteria (OR 1.07; 95 %CI: 1.02 – 1.12; P < 0.01) but with a lower likelihood of performing systematic biopsies (OR 0.91; 95 %CI: 0.85 – 0.97; P < 0.01). More than half (55.6 %) of patients with NDBE underwent surveillance EGD sooner (range 1 – 29 months) than the recommended interval.

Conclusion Adherence to quality indicators and surveillance guidelines in BE is low. Operator characteristics, including experience with endoscopic therapy for BE and time in practice predicted practice pattern. Future efforts are needed to reduce variability in practice and promote high-value care.
Neues Verfahren zur Liposuktion und Fettaugmentation nach Chordektomie
Authors: Haubner Frank , Lorenz Anne , Kummer Peter , Álvarez J. Carmelo Pérez
Published: March 2018

Fettaugmentationen der Stimmlippen sind ein etabliertes Verfahren in der Hals-Nasen-Ohrenheilkunde. Aktuell
wird dieses Verfahren auch bei Patienten mit endolaryngealen Defekten nach Laser-Chordektomie diskutiert. Der
Artikel beschreibt diesbezüglich ein minimal-invasives Verfahren zur primären Liposuktion und Fettaugmentation
bei Patienten nach der Resektion eines pT1a Stimmlippenkarzinoms. Dieses neue Verfahren erwies sich als
sichere und technisch einfache Methode zur Rekonstruktion von Stimmlippendefekten. Relevante Komplikationen
wurden nicht beobachtet.
Resonance transparency with low-loss in toroidal planar metamaterial
Authors: Xiang Tianyu , Lei Tao , Hu Sen , Chen Jiao , Huang Xiaojun , Yang Helin
Published: March 2018

A compact planar construction composed of asymmetric split ring resonators was designed with a low-loss, high Q-factor resonance transparency at microwave frequency. The singularity property of the proposed metamaterial owing to the enhanced toroidal dipole T is demonstrated via numerical and experimental methods. The transmission peak can reach up to 0.91 and the loss is perfectly repressed, which can be testified by radiated power, H-field distributions, and the imaginary parts of effective permittivity and permeability. The designed planar metamaterial may have numerous potential applications at microwave, terahertz, and optical frequency, e.g., for ultrasensitive sensing, slow-light devices, lasing spacers, even invisible information transfer.
Emergence, evolution, and control of multistability in a hybrid topological quantum/classical system
Authors: Wang Guanglei , Xu Hongya , Lai Ying-Cheng
Published: March 2018

We present a novel class of nonlinear dynamical systems—a hybrid of relativistic quantum and classical systems and demonstrate that multistability is ubiquitous. A representative setting is coupled systems of a topological insulator and an insulating ferromagnet, where the former possesses an insulating bulk with topologically protected, dissipationless, and conducting surface electronic states governed by the relativistic quantum Dirac Hamiltonian and the latter is described by the nonlinear classical evolution of its magnetization vector. The interactions between the two are essentially the spin transfer torque from the topological insulator to the ferromagnet and the local proximity induced exchange coupling in the opposite direction. The hybrid system exhibits a rich variety of nonlinear dynamical phenomena besides multistability such as bifurcations, chaos, and phase synchronization. The degree of multistability can be controlled by an external voltage. In the case of two coexisting states, the system is effectively binary, opening a door to exploitation for developing spintronic memory devices. Because of the dissipationless and spin-momentum locking nature of the surface currents of the topological insulator, little power is needed for generating a significant current, making the system appealing for potential applications in next generation of low power memory devices.
Exploring microwave resonant multi-point ignition using high-speed schlieren imaging
Authors: Liu Cheng , Zhang Guixin , Xie Hong , Deng Lei , Wang Zhi
Published: March 2018

Microwave plasma offers a potential method to achieve rapid combustion in a high-speed combustor. In this paper, microwave resonant multi-point ignition and its control method have been studied via high-speed schlieren imaging. The experiment was conducted with the microwave resonant ignition system and the schlieren optical system. The microwave pulse in 2.45 GHz with 2 ms width and 3 kW peak power was employed as an ignition energy source to produce initial flame kernels in the combustion chamber. A reflective schlieren method was designed to illustrate the flame development process with a high-speed camera. The bottom of the combustion chamber was made of a quartz glass coated with indium tin oxide, which ensures sufficient microwave reflection and light penetration. Ignition experiments were conducted at 2 bars of stoichiometric methane-air mixtures. Schlieren images show that flame kernels were generated at more than one location simultaneously and flame propagated with different speeds in different flame kernels. Ignition kernels were discussed in three types according to their appearances. Pressure curves and combustion duration also show that multi-point ignition plays a significant role in accelerating combustion.
The intrinsic interface properties of the top and edge 1T/2H MoS2 contact: A first-principles study
Authors: Bai Hui-Fang , Xu Li-Chun , Di Mao-Yun , Hao Lu-Yao , Yang Zhi , Liu Rui Ping , Li Xiu Yan
Published: March 2018

The promised performance of monolayer molybdenum disulfide (MoS2)-based devices is hindered by the high electrical resistance at the metal-MoS2 contact. Benefitting from the metallic phase of MoS2, 1T-MoS2 is considered a potential electrode material for the semiconducting 2H-MoS2. In this paper, we report a comparative study of the allotropic 1T/2H MoS2 contact with different contact types. The edge-contact interface has a low tunnel barrier, high charge density, and even Ohmic contact with no Schottky barrier, which implies that this contact may overcome the resistance limit for the electrode-MoS2 contact. The outstanding interface properties of the 1T/2H MoS2 edge contact originate from the excess in-plane dangling bonds in the edge position. Based on our results, the edge-contact model is ideal for the 1T/2H MoS2 contact and may solve the problem of MoS2 contact resistance.
Extension of the effective relativistic coupling by asymptotic representation (ERCAR) approach to multi-dimensional potential energy surfaces: 3D model for CH3I
Authors: Wittenbrink Nils , Eisfeld Wolfgang
Published: March 2018

The Effective Relativistic Coupling by Asymptotic Representation (ERCAR) approach is a new method developed by us over the past few years that allows for the accurate diabatic representation of a molecular Coulomb and spin-orbit Hamiltonian and yields an analytic potential energy surface (PES) model for use in quantum dynamics simulations. So far, we focused on the single one dissociation coordinate defining the asymptote for diabatic representation and corresponding to removing a single, strongly relativistic atom from the remaining fragment. In the present study, we extend this approach to multiple dimensions for the first time. To this end, a 3D PES model is developed for the methyl iodide (CH3I) system accounting for all totally symmetric coordinates (C–I stretch, CH3 umbrella, and CH3 breathing modes). The model parameters are fitted with respect to high-level ab initio reference data for the spin space (“spin-free”) states which are reproduced with very good accuracy. The ERCAR method also yields the fine structure states and energies which are not computed ab initio. This is particularly important for the 1Q1 and 3Q0 fine structure states of CH3I which form an intersection that is considered key for the photodissociation dynamics of the system. Our new model shows that this intersection is considerably curved in the 2D subspace of the C–I stretch and CH3 umbrella coordinate. This will certainly affect the complicated nonadiabatic photodissociation dynamics of CH3I. The construction of a full 9D diabatic PES model is currently in progress.
Hydration dynamics of a lipid membrane: Hydrogen bond networks and lipid-lipid associations
Authors: Srivastava Abhinav , Debnath Ananya
Published: March 2018

Dynamics of hydration layers of a dimyristoylphosphatidylcholine (DMPC) bilayer are investigated using an all atom molecular dynamics simulation. Based upon the geometric criteria, continuously residing interface water molecules which form hydrogen bonds solely among themselves and then concertedly hydrogen bonded to carbonyl, phosphate, and glycerol head groups of DMPC are identified. The interface water hydrogen bonded to lipids shows slower relaxation rates for translational and rotational dynamics compared to that of the bulk water and is found to follow sub-diffusive and non-diffusive behaviors, respectively. The mean square displacements and the reorientational auto-correlation functions are slowest for the interfacial waters hydrogen bonded to the carbonyl oxygen since these are buried deep in the hydrophobic core among all interfacial water studied. The intermittent hydrogen bond auto-correlation functions are calculated, which allows breaking and reformations of the hydrogen bonds. The auto-correlation functions for interfacial hydrogen bonded networks develop humps during a transition from cage-like motion to eventual power law behavior of t−3/2. The asymptotic t−3/2 behavior indicates translational diffusion dictated dynamics during hydrogen bond breaking and formation irrespective of the nature of the chemical confinement. Employing reactive flux correlation analysis, the forward rate constant of hydrogen bond breaking and formation is calculated which is used to obtain Gibbs energy of activation of the hydrogen bond breaking. The relaxation rates of the networks buried in the hydrophobic core are slower than the networks near the lipid-water interface which is again slower than bulk due to the higher Gibbs energy of activation. Since hydrogen bond breakage follows a translational diffusion dictated mechanism, chemically confined hydrogen bond networks need an activation energy to diffuse through water depleted hydrophobic environments. Our calculations reveal that the slow relaxation rates of interfacial waters in the vicinity of lipids are originated from the chemical confinement of concerted hydrogen bond networks. The analysis suggests that the networks in the hydration layer of membranes dynamically facilitate the water mediated lipid-lipid associations which can provide insights on the thermodynamic stability of soft interfaces relevant to biological systems in the future.
Dispersion characteristics of V-band radial-line backward-wave oscillators with arbitrary periodic shallow rectangular grooves
Authors: Yang Fuxiang , Zhang Xiaoping , Bai Zhen
Published: March 2018

The dispersion characteristics of radial-line slow wave structures with shallow rectangular grooves are examined using the Borgins's potential function method. The whole structure is considered as one region with grooves that satisfy the Rayleigh criterion. In this region, an appropriate Fourier expansion of traveling waves is applicable. By applying suitable boundary conditions, the dispersion equations of an infinite system are obtained, which are solved numerically by calculation and simulation. Comparisons of analytic and numerical results with calculation and simulation show excellent agreement and justify a high degree of confidence in the validity of the theory. The Q-factor and coupling impedance of TM02 mode are higher than that of TM01 mode and that of the quasi-TEM mode with special parameters, while the starting current of TM02 mode is lower than that of TM01 and quasi-TEM modes, which makes the TM02 mode dominate over the start-up of the oscillation. Structural parameters, including period length, corrugation depth, and tube width as well as original radius are considered in detail to choose the exact operating frequency and modes of V-band radial-line backward-wave oscillators (BWOs). More importantly, the presented new dispersion equations can provide a theoretical guidance for the design of V-band radial-line BWOs.
The electro-thermal stability of tantalum relative to aluminum and titanium in cylindrical liner ablation experiments at 550 kA
Authors: Steiner Adam M. , Campbell Paul C. , Yager-Elorriaga David A. , Cochrane Kyle R. , Mattsson Thomas R. , Jordan Nicholas M. , McBride Ryan D. , Lau Y. Y. , Gilgenbach Ronald M.
Published: March 2018

Presented are the results from the liner ablation experiments conducted at 550 kA on the Michigan Accelerator for Inductive Z-Pinch Experiments. These experiments were performed to evaluate a hypothesis that the electrothermal instability (ETI) is responsible for the seeding of magnetohydrodynamic instabilities and that the cumulative growth of ETI is primarily dependent on the material-specific ratio of critical temperature to melting temperature. This ratio is lower in refractory metals (e.g., tantalum) than in non-refractory metals (e.g., aluminum or titanium). The experimental observations presented herein reveal that the plasma-vacuum interface is remarkably stable in tantalum liner ablations. This stability is particularly evident when contrasted with the observations from aluminum and titanium experiments. These results are important to various programs in pulsed-power-driven plasma physics that depend on liner implosion stability. Examples include the magnetized liner inertial fusion (MagLIF) program and the cylindrical dynamic material properties program at Sandia National Laboratories, where liner experiments are conducted on the 27-MA Z facility.