bluuebunny/crossref_metadata_2025 huggingface dataset:
Mutations of PKA cyclic nucleotide-binding domains reveal novel aspects of cyclic nucleotide selectivity
Authors: Lorenz Robin , Moon Eui-Whan , Kim Jeong Joo , Schmidt Sven H. , Sankaran Banumathi , Pavlidis Ioannis V. , Kim Choel , Herberg Friedrich W.
Published: June 2017

Cyclic AMP and cyclic GMP are ubiquitous second messengers that regulate the activity of effector proteins in all forms of life. The main effector proteins, the 3′,5′-cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and the 3′,5′-cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG), are preferentially activated by cAMP and cGMP, respectively. However, the molecular basis of this cyclic nucleotide selectivity is still not fully understood. Analysis of isolated cyclic nucleotide-binding (CNB) domains of PKA regulatory subunit type Iα (RIα) reveals that the C-terminal CNB-B has a higher cAMP affinity and selectivity than the N-terminal CNB-A. Here, we show that introducing cGMP-specific residues using site-directed mutagenesis reduces the selectivity of CNB-B, while the combination of two mutations (G316R/A336T) results in a cGMP-selective binding domain. Furthermore, introducing the corresponding mutations (T192R/A212T) into the PKA RIα CNB-A turns this domain into a highly cGMP-selective domain, underlining the importance of these contacts for achieving cGMP specificity. Binding data with the generic purine nucleotide 3′,5′-cyclic inosine monophosphate (cIMP) reveal that introduced arginine residues interact with the position 6 oxygen of the nucleobase. Co-crystal structures of an isolated CNB-B G316R/A336T double mutant with either cAMP or cGMP reveal that the introduced threonine and arginine residues maintain their conserved contacts as seen in PKG I CNB-B. These results improve our understanding of cyclic nucleotide binding and the molecular basis of cyclic nucleotide specificity.
Cross-Linguistic Differences in Bilinguals' Fundamental Frequency Ranges
Authors: Ordin Mikhail , Mennen Ineke
Published: June 2017

Purpose

We investigated cross-linguistic differences in fundamental frequency range (FFR) in Welsh-English bilingual speech. This is the first study that reports gender-specific behavior in switching FFRs across languages in bilingual speech.

Method

FFR was conceptualized as a behavioral pattern using measures of span (range of fundamental frequency—in semitones—covered by the speaker's voice) and level (overall height of fundamental frequency maxima, minima, and means of speaker's voice) in each language.

Results

FFR measures were taken from recordings of 30 Welsh-English bilinguals (14 women and 16 men), who read 70 semantically matched sentences, 35 in each language. Comparisons were made within speakers across languages, separately in male and female speech. Language background and language use information was elicited for qualitative analysis of extralinguistic factors that might affect the FFR.

Conclusions

Cross-linguistic differences in FFR were found to be consistent across female bilinguals but random across male bilinguals. Most female bilinguals showed distinct FFRs for each language. Most male bilinguals, however, were found not to change their FFR when switching languages. Those who did change used different strategies than women when differentiating FFRs between languages. Detected cross-linguistic differences in FFR can be explained by sociocultural factors. Therefore, sociolinguistic factors are to be taken into account in any further study of language-specific pitch setting and cross-linguistic differences in FFR.
Typical Toddlers' Participation in “Just-in-Time” Programming of Vocabulary for Visual Scene Display Augmentative and Alternative Communication Apps on Mobile Technology: A Descriptive Study
Authors: Holyfield Christine , Drager Kathryn , Light Janice , Caron Jessica Gosnell
Published: June 2017

Purpose

Augmentative and alternative communication (AAC) promotes communicative participation and language development for young children with complex communication needs. However, the motor, linguistic, and cognitive demands of many AAC technologies restrict young children's operational use of and influence over these technologies. The purpose of the current study is to better understand young children's participation in programming vocabulary “just in time” on an AAC application with minimized demands.

Method

A descriptive study was implemented to highlight the participation of 10 typically developing toddlers (Mage: 16 months, range: 10–22 months) in just-in-time vocabulary programming in an AAC app with visual scene displays.

Results

All 10 toddlers participated in some capacity in adding new visual scene displays and vocabulary to the app just in time. Differences in participation across steps were observed, suggesting variation in the developmental demands of controls involved in vocabulary programming.

Conclusions

Results from the current study provide clinical insights toward involving young children in AAC programming just in time and steps that may allow for more independent participation or require more scaffolding. Technology designed to minimize motor, cognitive, and linguistic demands may allow children to participate in programming devices at a younger age.
Using Pupillometry to Investigate Sentence Comprehension in Children With and Without Specific Language Impairment
Authors: Lum Jarrad A. G. , Youssef George J. , Clark Gillian M.
Published: June 2017

Purpose

In this study pupillometry was used to investigate the allocation of attentional resources associated with sentence comprehension in children with and without specific language impairment (SLI).

Method

Eighteen children with SLI (age:
M
= 6.4 years) and 18 typically developing (TD) children (age:
M
= 6.3 years) participated in the study. A sentence comprehension task was presented that comprised items designated as easy or hard. Easy sentences contained 4 or 5 words, and hard sentences contained 6 or 7 words.

Results

For the TD group, pupil size was significantly larger when comprehending hard sentences compared with easy sentences. There was no effect of sentence difficulty on pupil size in the SLI group. Comparisons between groups revealed pupil sizes for the SLI group were significantly larger than those for the TD group for easy sentences. There were no group differences for the hard sentences.

Conclusion

In TD children, pupillometry was sensitive to the attentional demands associated with sentence comprehension. Between-subjects comparisons indicated that the TD group allocated less attention than did the children with SLI for the easy sentences but not for the hard sentences. This study provides evidence of attentional differences between children with SLI and TD children under conditions of low processing demands.
Energy harvesting and wireless data transmission system for rotor instrumentation in electrical machines
Authors: Llano Danilo X. , Abdi Salman , Tatlow Mark , Abdi Ehsan , McMahon Richard A.
Published: June 2017

It is desirable to measure rotor quantities such as currents and temperatures in an electrical machine for design verification and condition monitoring purposes. A Bluetooth module which sends data from the rotor was previously reported in literature, but this module was battery powered, and therefore the duration of the tests was limited. This study presents a solution to this problem by developing a rotor‐mounted power supply system which can harvest energy from the magnetic field inside the machine, by fixing an external loop to the rotor and making use of the induced voltage in the loop. A full‐bridge rectifier, boost converter and battery charging module were developed to supply sufficient power to a bespoke Bluetooth transmission system and associated sensor circuitry.
Self‐adaptive inertia control of DC microgrid based on fast predictive converter regulation
Authors: Wang Yi , Yu Ming , Li Yonggang
Published: June 2017

To solve the problem of low inertia in DC microgrid and enable the distributed units to provide adaptive inertia support for the system under disturbance, this study proposes a novel adaptive inertia control strategy for DC microgrid combined with fast predictive converter control. In this strategy, adaptive coordinated inertia control of wind power system, AC power grid and energy storage system of the microgrid is designed according to the characteristics of corresponding micro‐sources. Therefore, inertial response of the DC microgrid under disturbance is improved through the regulation of controllable inertia coefficient of each converter. In addition, to avoid control hysteresis and adjustment error, a fast converter local control method based on model predictive approach is proposed to cooperate with the rapid inertia adjustment strategy. To verify the effectiveness of the proposed adaptive inertia control method based on model predictive approach, contrastive simulations are conducted using the proposed control strategy and the traditional control strategy separately based on MATLAB/Simulink. The results show that the proposed control method can effectively improve the transient response to disturbance of the system and guarantee the stability of DC bus voltage as well as the output power quality on AC side of grid‐connected converter.
Transition-Metal- and Halogen-Free Oxidation of Benzylic sp3 C–H Bonds to Carbonyl Groups Using Potassium Persulfate
Authors: Hu Yixin , Zhou Lihong , Lu Wenjun
Published: June 2017

Aryl carbonyl compounds including acetophenones, benzophenones, imides, and benzoic acids are prepared from benzyl substrates using potassium persulfate as oxidant with catalytic pyridine in acetonitrile under mild conditions. Neither transition metals nor halogens are involved in the reactions.
Construction of Boron-Containing Aromatic Heterocycles
Authors: Kinjo Rei , Su Bochao
Published: June 2017

Boron-containing aromatic systems exhibit unique electronic properties and reactivities that have been extensively studied for a long time. This review highlights the recent developments in the synthesis of aromatic boron-containing heterocycles. The organization of the contents is based on the sizes of rings and the heteroatoms other than boron. Early work in the field is briefly introduced, but the main focus is on recent reports published during the period of 2008 through 2016.

1 Introduction

2 Five-Membered Rings

2.1 Borole Derivatives

2.2 B,N-Heterocycles

2.3 B,O-Heterocycles

3 Six-Membered Rings

3.1 Borabenzene Derivatives

3.2 Boratabenzene Derivatives

3.3 1,4-Diborabenzene

3.4 B,N-Heterocycles

3.5 B,E-Heterocycles (E = O, S, P, Te)

4 Three-Membered Rings

4.1 Borirenes

4.2 Azadiboriridines

4.3 Triboracyclopropenyl Dianion

5 Four-Membered Rings

5.1 bicyclo-Tetraborane(4)

5.2 1,3-Diborete

5.3 B,E-Heterocycles (E = N, P, As, Sb, Bi, O, S, Se)

6 Seven-Membered Rings (Borepines)

7 Conclusion and Perspective
Lycopodium Alkaloids: An Intramolecular Michael Reaction Approach
Authors: Saha Mrinmoy , Carter Rich
Published: June 2017

The Lycopodium alkaloids possess a rich history that has captured the attention of synthetic chemists across the globe. This large family consists of over 250 known natural products with diverse structural features and noteworthy biological activity. Herein, we interweave the synthetic accomplishments by others in the field with our own unified strategy to accessing multiple subfamilies of the Lycopodium alkaloids. This discussion includes lycopodine, the C10-hydroxy Lycopodium alkaloids (10-hydroxylycopodine, deacetylpaniculine and paniculine), pelletierine, cermizine D, fastigiatine, himeradine A, clavolonine and 7-hydroxylycopodine. A unifying feature of much of the work discussed within this account is the use of intramolecular Michael additions to construct key ring systems within the Lycopodium alkaloids. Examples include the use of an intramolecular keto-sulfone Michael reaction and an intramolecular heteroatom Michael reaction.

1 General Background on Lycopodium Alkaloids

2 Development of a Strategy for Lycopodium Alkaloids

2.1 Generalized Strategy

2.2 Known Syntheses of C10-Functionalized Lycopodium Alkaloids

3 Quinolizidine-Type Alkaloids

3.1 Background

3.2 Development of the Heteroatom Michael Reaction

3.3 Synthesis of the Core Lycopodine Building Block: Pelletierine

3.4 Total Synthesis of Cermizine D

3.5 Synthesis of the Eastern Half of Himeradine A

4 Lycopodine-Type Alkaloids

4.1 Total Syntheses of Lycopodine

4.1.1 Earlier Racemic Syntheses

4.1.2 Approach Toward the Tricyclic Skeleton of Lycopodine: Intramolecular Mannich

4.1.3 Enantioselective Total Syntheses of Lycopodine

4.2 Total Syntheses of Clavolonine (8-Hydroxylycopodine)

4.3 Total Synthesis of 7-Hydroxylycopodine

4.4 Synthetic Route for 10-Hydroxy Lycopodium Alkaloids

4.4.1 Background

4.4.2 Total Syntheses

4.4.3 Impact of the C10-Stereochemistry

5 Conclusion
Clival Osteomyelitis Presenting as a Skull Base Mass
Authors: Michalowicz Matthew , Ramanathan Murugappan
Published: June 2017

Central skull base osteomyelitis is a rare, but potentially life-threatening disease entity often lacking otologic symptoms or external auditory canal pathology. We present a case of a man in his 70s who had developed cranial nerve deficits with radiographic evidence that was consistent with a tumor due to this uncommon entity. The radiologic findings and our experience are discussed to increase awareness in the otolaryngology community.
Patienten zeigen sich zufrieden mit der Arzt-Patienten-Kommunikation – eine Pilotstudie mit dem „Individual Clinician Feedback“- Fragebogen
Authors: Prengel Peggy , Kotte Nina , Antoine Sunya-Lee , Eikermann Michaela , Neugebauer Edmund , Stahl Katja , Pieper Dawid
Published: June 2017

Ziel der Studie Die Patientenzentrierung als ein wesentliches Qualitätsmerkmal der Patientenversorgung gewinnt immer mehr an Bedeutung. Das Ziel des Pilotprojektes ist es, Einblicke in die Arzt-Patienten-Kommunikation aus Patientensicht zu gewinnen. Im Vordergrund steht die Erprobung des deutschen Fragebogens in einer Klinik der Maximalversorgung.

Methodik Der deutsche „Individual Clinician Feedback“- Fragebogen (ICF) wurde in einer Pilotstudie in den Spezialsprechstunden einer Klinik an einer freiwilligen Kohorte chirurgisch tätiger Ärzte getestet. Im Erhebungszeitraum von Juni – August 2015 wurde der Fragebogen an die Patienten ausgegeben. Dem Arzt werden seine Bewertungsergebnisse (Feedback) in komprimierter Form als Score zur Verfügung gestellt. Die Bewertung erfolgt auf einer Skala von 1 bis 10, wobei 10 „sehr gut“ ist.

Ergebnisse Es wurden 12 Ärzte aus 5 Fachabteilungen rekrutiert. Es konnte eine hohe Rücklaufquote von 46% (n=219) erzielt werden. Die Kommunikation bewerten die Patienten als sehr gut (im Mittel über alle Items und Ärzte 8,5–9,5 Punkte). 89% der Patienten hatten das Gefühl, dass sich der Arzt genügend Zeit für sie genommen hat, dabei waren 50% der Patienten 11–20 min beim Arzt. Für 12% der Patienten bestanden nach der Behandlung noch offene Fragen, die sie nicht gestellt haben. Zu 19 bzw. 21% gaben die Patienten an, dass der Arzt nicht angeboten hat, Fragen zu stellen oder dass sie es einfach am Ende der Behandlung vergessen haben.

Schlussfolgerung Die Ergebnisse der Pilotstudie gehen mit einer guten Rücklaufquote einher und die Patienten zeigten sich größtenteils sehr zufrieden mit der Arzt-Patienten-Kommunikation. Ein Selektionsbias unter den teilnehmenden Ärzten ist jedoch wahrscheinlich.
Eine Aufgabe mit Schlüsselfunktion
Authors: Stricker Cornelia , Schlüer Anna-Barbara , Händler-Schuster Daniela
Published: June 2017

Erfahrungsbericht Im Rahmen ihres Studiums Master of Science in Nursing an
der Zürcher Hochschule für Angewandte Wissenschaften in Winterthur absolvierte
Cornelia Stricker ein Workshadowing im Pflegedienst des
Universitätskinderspitals Zürich. Innerhalb von zwei Wochen erhielt sie einen
direkten Einblick in die Pflegepraxis der Pflegeexpertinnen APN Kardiologie, APN
Onkologie und APN Kontinenz und über ihre Verankerung in der klinischen Praxis.
Hier beschreibt sie die vielfältigen Aufgaben pädiatrischer Pflegeexperten APN
in der klinischen Praxis und zeigt Möglichkeiten des Umgangs auf.
Morbiditätskompression bei Schlaganfall? Langzeitanalysen zur Veränderung des Auftretens von Schlaganfall
Authors: Bachus Lena , Eberhard Sveja , Weißenborn Karin , Muschik Denise , Epping Jelena , Geyer Siegfried
Published: June 2017

Ziel der Studie Nach Fries liegt Morbiditätskompression dann vor, wenn das Alter des Eintretens von Krankheit und chronischer Behinderung und Tod über die Zeit ansteigt oder wenn Erkrankungsraten über die Zeit stärker oder im gleichen Maße sinken wie die standardisierten Sterberaten. In beiden Fällen wird gesunde Lebenszeit gewonnen. Die Befunde der bisher durchgeführten Studien sind uneinheitlich, und es gibt nur wenige zu spezifischen Erkrankungen. Am Beispiel des Schlaganfalls wird untersucht, ob über den untersuchten Neunjahreszeitraum Morbiditätskompression stattgefunden hat. Dies bezieht sich auf Veränderungen der Raten von Schlaganfall und Tod. Zusätzlich wird untersucht, ob sich das Alter bei Manifestation von Schlaganfall und das Sterbealter wie von Fries angenommen bei Frauen und Männern nach oben verschieben.

Methodik Die Analysen basieren auf den pseudonymisierten Daten einer gesetzlichen Krankenversicherung der Jahre 2006–2014. Die Analysen wurden für alle Schlaganfälle sowie differenziert nach Hirninfarkten und Blutungen (ICD 10: I60-I62) durchgeführt. Für jedes Jahr standen die Daten von ca. 2 Mio. Versicherten zur Verfügung. Die Berechnungen wurden mit Survivalanalysen sowie mit multivariater Regression durchgeführt.

Ergebnisse Die Raten reduzierten sich bei beiden Geschlechtern, jedoch nur für blutungsbedingte Schlaganfälle. Die Veränderungen des Eintrittsalters waren schwer interpretierbar. Das Sterbealter sowie die standardisierten Sterberaten veränderten sich nur bei Männern.

Schlussfolgerung Belege für die Kompressionsthese wurden nur für Änderungen in den Raten blutungsbedingter Schlaganfälle gefunden. Diese Befunde beziehen sich auf eine einzige Erkrankung, die relativ spät im Lebensverlauf eintritt. Eine abschließende Beurteilung über das Vorliegen von Morbiditätskompression ist erst nach der Untersuchung einer breiten Spanne von Erkrankungen möglich.
Simulations of simple linoleic acid-containing lipid membranes and models for the soybean plasma membranes
Authors: Zhuang Xiaohong , Ou Anna , Klauda Jeffery B.
Published: June 2017

The all-atom CHARMM36 lipid force field (C36FF) has been tested with saturated, monounsaturated, and polyunsaturated lipids; however, it has not been validated against the 18:2 linoleoyl lipids with an unsaturated sn-1 chain. The linoleoyl lipids are common in plants and the main component of the soybean membrane. The lipid composition of soybean plasma membranes has been thoroughly characterized with experimental studies. However, there is comparatively less work done with computational modeling. Our molecular dynamics (MD) simulation results show that the pure linoleoyl lipids, 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (18:0/18:2) and 1,2-dilinoleoyl-sn-glycero-3-phosphocholine (di-18:2), agree very well with the experiments, which demonstrates the accuracy of the C36FF for the computational study of soybean membranes. Based on the experimental composition, the soybean hypocotyl and root plasma membrane models are developed with each containing seven or eight types of linoleoyl phospholipids and two types of sterols (sitosterol and stigmasterol). MD simulations are performed to characterize soybean membranes, and the hydrogen bonds and clustering results demonstrate that the lipids prefer to interact with the lipids of the same/similar tail unsaturation. All the results suggest that these two soybean membrane models can be used as a basis for further research in soybean and higher plant membranes involving membrane-associated proteins.
First demonstration of simultaneous measurement of beam current, beam position, and beam tilt on induction linac using combined B-dot monitor
Authors: He Xiaozhong , Pang Jian , Chen Nan , Li Qin , Dai Wenhua , Ma Chaofan , Zhao Liangchao , Gao Feng , Dai Zhiyong
Published: June 2017

The authors previously reported that the axial B-dots can be used to directly measure the beam tilt and demonstrated that the axial B-dots are applicable to a coaxial calibration stand. In this study, a combined B-dot monitor composed of four axial B-dot loops and four azimuthal ones is tested for the simultaneous measurement of the time-varying beam current, beam offset, and beam tilt at the output of the injector of the DRAGON-I induction linac. In the experiments, the beam offset and beam tilt at the position of the monitor are proportionally adjusted using a pair of steering coils. Eight waveforms acquired from the B-dot monitor are analyzed to reconstruct the time-varying beam current, beam offset, and beam tilt. The original signals of both the azimuthal B-dot and the axial B-dot ports change significantly with respect to the current applied to the steering coils. The measured beam tilt is linearly dependent on the current applied to the steering coils and agrees well with the measured beam offset.
Full area covered 3D profile measurement of special-shaped optics based on a new prototype non-contact profiler
Authors: Du Hui-Lin , Zhou Zhao-Zhong , Sun Ze-Qing , Ju Bing-Feng , Xu Shaoning , Sun Anyu
Published: June 2017

A new prototype non-contact profiler based on surface tracking has been specially developed. Surface tracking is carried out by a specially designed dual stage probe system with the aid of a four-Degree Of Freedom high-precision motion platform. The dual stage probe system keeps a short-range optical probe constantly tracking the surface by a self-developed voice coil motor servo, by which a wide measuring range of up to 10 mm is realized. The system performance evaluation including resolution, repeatability, and scanning speed proved the good capability of the new prototype non-contact profiler. To realize a full area covered 3D profile measurement of special-shaped optics within one scanning procedure, a signal intensity monitor integrated in the surface tracking controller is specially developed. In the experiment, a snip-single-corner-rectangular-shaped freeform surface was successfully measured over full area by the new non-contact profiler. This work provides an effective solution for 3D profile measurement of special-shaped optical surfaces over full reflecting area. Experimental results demonstrate that the proposed measuring system is of great significance in quality evaluation of optical surfaces.
First simultaneous measurements of Reynolds stress with ball-pen and Langmuir probes
Authors: Grover Ondrej , Adamek Jiri , Seidl Jakub , Devitre Alexis , Sos Miroslav , Vondracek Petr , Bilkova Petra , Hron Martin
Published: June 2017

A new multi-pin probe head was installed and tested at the COMPASS tokamak. The probe head consists of several ball-pen and Langmuir probes in similar geometric configurations, which enables fast, simultaneous measurements of the radial and poloidal electric field components from differences of plasma or floating potentials using appropriately positioned ball-pen or Langmuir probes, respectively. The fast measurements of the radial electric field are compared with other methods of measuring selected frequency components of the radial electric field. The radial profiles of the Reynolds stress calculated from correlations of electric field fluctuations obtained by either probe type are compared along with their spectral composition. Lower Reynolds stress values are found for Langmuir probes in comparison to ball-pen probes due to negative contributions from higher frequency fluctuations possibly associated with electron temperature fluctuations.
The roles of carrier concentration and interface, bulk, and grain-boundary recombination for 25% efficient CdTe solar cells
Authors: Kanevce A. , Reese M. O. , Barnes T. M. , Jensen S. A. , Metzger W. K.
Published: June 2017

CdTe devices have reached efficiencies of 22% due to continuing improvements in bulk material properties, including minority carrier lifetime. Device modeling has helped to guide these device improvements by quantifying the impacts of material properties and different device designs on device performance. One of the barriers to truly predictive device modeling is the interdependence of these material properties. For example, interfaces become more critical as bulk properties, particularly, hole density and carrier lifetime, increase. We present device-modeling analyses that describe the effects of recombination at the interfaces and grain boundaries as lifetime and doping of the CdTe layer change. The doping and lifetime should be priorities for maximizing open-circuit voltage (Voc) and efficiency improvements. However, interface and grain boundary recombination become bottlenecks for device performance at increased lifetime and doping levels. This work quantifies and discusses these emerging challenges for next-generation CdTe device efficiency.
Zn doping induced conductivity transformation in NiO films for realization of p-n homo junction diode
Authors: Dewan Sheetal , Tomar Monika , Tandon R. P. , Gupta Vinay
Published: June 2017

Mixed transition metal oxide, zinc doped NiO, ZnxNi1−xO (x = 0, 0.01, 0.02, 0.05, and 0.10), thin films have been fabricated by the RF magnetron sputtering technique in an oxygen deficit ambience at a growth temperature of 400 °C. The present report highlights the effect of Zn doping in NiO thin films on its structural, optical, and electrical properties. Optical transmission enhancement and band gap engineering in a-axis oriented NiO films have been demonstrated via Zn substitution. Hall effect measurements of the prepared samples revealed a transition from p-type to n-type conductivity in NiO at 2% Zn doping. A NiO based transparent p-n homojunction diode has been fabricated successfully, and the conduction mechanism dominating the diode properties is reported in detail. Current-voltage (I-V) characteristics of the homojunction diode are found to obey the Space Charge Limited Conduction mechanism with non-ideal square law behaviour.
Anomalies and peculiarities of radiation-induced light absorption in pure silica optical fibers at different temperatures
Authors: Kashaykin Pavel F. , Tomashuk Alexander L. , Salgansky Mikhail Yu. , Guryanov Alexey N. , Dianov Evgeny M.
Published: June 2017

Undoped-silica-core F-doped-silica-cladding optical fibers (“undoped fibers”) are an important fiber type for applications requiring resistance to ionizing radiation (e.g., the nuclear industry, space, and military applications), the most important fundamental radiation-induced color centers arising in such fibers being self-trapped holes (STH). Despite the previous in-depth STH investigations, there have remained a few not-fully understood issues, such as the relationship between the radiation-induced absorption (RIA) bands due to STH in undoped fibers, on the one hand, and in bulk silica samples, on the other, the role of strain in the silica network in the STH occurrence, and possible peculiarities of short-lived STH-like radiation-induced color centers at temperatures above RT. To address these issues, we investigate the RIA spectra in undoped fibers with different frozen-in strain in their silica network immediately in the process of γ-irradiation to a dose of 1 kGy, the irradiation temperature being in the range ±60 °C or liquid nitrogen temperature (LNT). Gaussian decomposition of the RIA spectra measured at LNT has yielded STH bands at 2.6 and 2.16 eV together with the “classical” STH bands at 1.88 and 1.63 eV observed in fibers more frequently than the former bands. Based on this observation, it is proposed that all the STH bands observable in fibers fall into two classes: those inherent in silica and those strain-assisted, which can adjoin each other in the fiber silica network. The inherent STH include the well-known low-temperature infrared absorption and the bands at 2.6 and 2.16 eV; the strain assisted STH, the 1.88- and 1.63-eV bands. The 1.88-eV band is argued to be due to STH1, the 1.63-eV one, due to STH2. Anomalously high RIA at T = 0 and +60 °C is revealed and explained for the first time. The former effect is found to be caused by extreme compression of silica at T ∼ 0 °C enhancing the strain-assisted STH bands. The anomaly at T = +60 °C is found to be due to a previously unknown broad RIA band at ∼1.08 eV, which is likely to be associated with STH or self-trapped electrons and to result from either large network strain at the compression phases of enhanced thermal oscillation, or large expansion at the opposite phases. The RIA enhancement at T = +60 °C observed in this paper for the first time can influence fiber applications in the nuclear industry associated with high temperatures and high dose rates.
Thermodiffusion as a means to manipulate liquid film dynamics on chemically patterned surfaces
Authors: Kalpathy Sreeram K. , Shreyes Amrita Ravi
Published: June 2017

The model problem examined here is the stability of a thin liquid film consisting of two miscible components, resting on a chemically patterned solid substrate and heated from below. In addition to surface tension gradients, the temperature variations also induce gradients in the concentration of the film by virtue of thermodiffusion/Soret effects. We study the stability and dewetting behaviour due to the coupled interplay between thermal gradients, Soret effects, long-range van der Waals forces, and wettability gradient-driven flows. Linear stability analysis is first employed to predict growth rates and the critical Marangoni number for chemically homogeneous surfaces. Then, nonlinear simulations are performed to unravel the interfacial dynamics and possible locations of the film rupture on chemically patterned substrates. Results suggest that appropriate tuning of the Soret parameter and its direction, in conjunction with either heating or cooling, can help manipulate the location and time scales of the film rupture. The Soret effect can either potentially aid or oppose film instability depending on whether the thermal and solutal contributions to flow are cooperative or opposed to each other.
Self-intermediate scattering function analysis of supercooled water confined in hydrophilic silica nanopores
Authors: Kuon Nicholas , Milischuk Anatoli A. , Ladanyi Branka M. , Flenner Elijah
Published: June 2017

We study the temperature dependence of the self-intermediate scattering function for supercooled water confined in hydrophilic silica nanopores. We simulate the simple point charge/extended model of water confined to pores of radii 20 Å, 30 Å, and 40 Å over a temperature range of 210 K to 250 K. First, we examine the temperature dependence of the structure of the water and find that there is layering next to the pore surface for all temperatures and diameters. However, there exists a region in the center of the pore where the density is nearly constant. Using the density profile, we divide confined water into different regions and compare the dynamics of the water molecules that start in these regions. To this end, we examine the mean-squared displacement and the self-intermediate scattering functions for the water hydrogens, which would allow one to connect our results with quasi-elastic neutron scattering experiments. We examine the dependence of the self-intermediate scattering function on the magnitude and direction of the wavevector, as well as the proximity to the silica surface. We also examine the rotational-translational decoupling. We find that the anisotropy of the dynamics and the rotational-translational decoupling is weakly temperature dependent.
Weakly nonlinear incompressible Rayleigh-Taylor instability in spherical geometry
Authors: Zhang J. , Wang L. F. , Ye W. H. , Wu J. F. , Guo H. Y. , Zhang W. Y. , He X. T.
Published: June 2017

In this research, a weakly nonlinear (WN) model for the incompressible Rayleigh-Taylor instability in cylindrical geometry [Wang et al., Phys. Plasmas 20, 042708 (2013)] is generalized to spherical geometry. The evolution of the interface with an initial small-amplitude single-mode perturbation in the form of Legendre mode (Pn) is analysed with the third-order WN solutions. The transition of the small-amplitude perturbed spherical interface to the bubble-and-spike structure can be observed by our model. For single-mode perturbation Pn, besides the generation of P2n and P3n, which are similar to the second and third harmonics in planar and cylindrical geometries, many other modes in the range of P0–P3n are generated by mode-coupling effects up to the third order. With the same initial amplitude, the bubbles at the pole grow faster than those at the equator in the WN regime. Furthermore, it is found that the behavior of the bubbles at the pole is similar to that of three-dimensional axisymmetric bubbles, while the behavior of the bubbles at the equator is similar to that of two-dimensional bubbles.
Numerical investigation on nonlinear effect and vortex formation of oscillatory flow throughout a short tube in a thermoacoustic Stirling engine
Authors: Yang Peng , Chen Hui , Liu Yingwen
Published: June 2017

In this paper, a two-dimensional axisymmetric model of a thermoacoustic Stirling engine with a short tube where the cross section narrows has been developed. The transient streamlines and vortex formation through short tubes with different diameters in oscillatory flow have been investigated visually by computational fluid dynamics. Three dimensionless parameters, Reynolds number (Re), Keulegan-Carpenter number (KC), and Womersley number (Wo), are used to describe the flow regime and vortex characteristic throughout the short tube. High Re and Wo numbers indicate that the oscillatory flow develops into the turbulent flow through the short tube. The KC number has a direct effect on the transition of streamlines and the development of the vortex. For a small cross section where KC ≈ 1, streamlines rotate and the vortex forms at both sides of the short tube. The vortex stays in the main flow region, and intensity varies as streamlines are convected downstream. The velocity along the radius presents a Poiseuille profile within the influence of the vortex. For a large cross section where KC < 1, streamlines pass the short tube with little rotation and the vortex disappears in the main flow region and confines near the short tube. The velocity profile tends to be flat. The nonlinear effects including instantaneous pressure drop and power dissipation throughout the short tube are also discussed. It shows that the time averaged pressure drop is generated at the cost of power dissipation. Finally, the “effectiveness” is applied to evaluate the performance of the short tube. The results suggest that increasing the diameter of the short tube is in favor of reducing power dissipation, which is beneficial to improve “effectiveness.”
Back diffusion of electrons in argon subjected to uniform time invariant orthogonal electric and magnetic fields
Authors: Dincer M. S. , Biricik Samet , Tezcan S. S. , Bektas S.
Published: June 2017

In this study, the processes of back diffusion in Ar subjected to crossed fields are analyzed by using the Monte Carlo simulation method in the E/N range of 50 to 500 Td (1 Td = 1 × 10–17 V cm2) for 0 < B/N < 25 × 10−19 T cm3. At a given constant E/N, escape factors decrease with an increasing crossed, reduced magnetic field B/N. This reduction in the escape factor is more pronounced in the lower E/N range. Furthermore, the mean number of collisions of back scattered electrons is quite large, and at a given E/N, the mean number of collisions decreases as the crossed B/N increases.
BaTiO3/SrTiO3 heterostructures for ferroelectric field effect transistors
Authors: Shoron Omor F. , Raghavan Santosh , Freeze Christopher R. , Stemmer Susanne
Published: June 2017

Integration of ultrathin ferroelectric thin films with semiconductors is of interest for negative capacitance transistors that exhibit internal voltage gain, which may allow for scaling the supply voltage of low power circuits. In this study, BaTiO3 thin films were grown on doped SrTiO3 channels using molecular beam epitaxy. The BaTiO3 films are ferroelectric despite their low thickness (∼10 nm). Parallel plate capacitor devices exhibit anti-clockwise hysteresis, and a comparison with reference structures without BaTiO3 shows that the polarization in the BaTiO3 thin films is switchable and controls the charge density in the channel. Field effect transistors were fabricated to study the effect of ferroelectricity on the transistor characteristics. Anti-clockwise hysteresis and a shift in threshold-voltage are observed in the output characteristics of the transistors. These properties make these heterostructures a suitable system for studying negative capacitance effects.
A high-performance and low cost SERS substrate of plasmonic nanopillars on plastic film fabricated by nanoimprint lithography with AAO template
Authors: Liu Long , Zhang Qian , Lu Yuanshen , Du Wei , Li Bin , Cui Yushuang , Yuan Changsheng , Zhan Peng , Ge Haixiong , Wang Zhenling , Chen Yanfeng
Published: June 2017

As a powerful spectroscopy technique, surface-enhanced Raman scattering (SERS) can provide non-destructive and sensitive characterization down to a single molecular level. Aiming to the main challenges of high-performance SERS-active substrates for their real-world applications involving the ultra-sensitive and reproducible signals detection and signal uniformity with large-area, herein, a facile and reliable strategy based on combination of thermal imprinting polycarbonate (PC) film with porous anodic aluminum oxide (AAO) mold and E-beam evaporation of gold is provided to fabricate a high-quality SERS-active substrate consisting of ultra-dense hot-spots with large-area uniformity. Two kinds of sub-10 nm gaps were obtained, including the nanogaps between the neighboring gold coated PC-nanopillars and those between gold on the top of the nanopillars and that on the base, which actually build up a three-dimensional (3D) hot-spot network for high-performance SERS detection. The effect of structural parameters on SERS enhancement was investigated numerically and experimentally, and by optimizing the structural parameters, a remarkable average SERS enhancement factor up to of 1.4×108 is achieved and it shows an excellent reproducibility with a relative standard deviation of 18%, which allows for enhanced practicability in the application of quantitative biochemical detection.
Temperature dependence of the interfacial magnetic anisotropy in W/CoFeB/MgO
Authors: Lee Kyoung-Min , Choi Jun Woo , Sok Junghyun , Min Byoung-Chul
Published: June 2017

The interfacial perpendicular magnetic anisotropy in W/CoFeB (1.2 ∼ 3 nm)/MgO thin film structures is strongly dependent on temperature, and is significantly reduced at high temperature. The interfacial magnetic anisotropy is generally proportional to the third power of magnetization, but an additional factor due to thermal expansion is required to explain the temperature dependence of the magnetic anisotropy of ultrathin CoFeB films. The reduction of the magnetic anisotropy is more prominent for the thinner films; as the temperature increases from 300 K to 400 K, the anisotropy is reduced ∼50% for the 1.2-nm-thick CoFeB, whereas the anisotropy is reduced ∼30% for the 1.7-nm-thick CoFeB. Such a substantial reduction of magnetic anisotropy at high temperature is problematic for data retention when incorporating W/CoFeB/MgO thin film structures into magneto-resistive random access memory devices. Alternative magnetic materials and structures are required to maintain large magnetic anisotropy at elevated temperatures.
Inhibitory action of allelochemicals from Artemisia nanschanica to control Pedicularis kansuensis, an annual weed of alpine grasslands
Authors: Shang Zhanhuan , Hou Yuan , Li Fei , Guo Cancan , Jia Tianhua , Degen A. Allan , White Andrew , Ding Luming , Long Ruijun
Published: June 2017

The inhibitory action of allelochemicals can be used effectively for biological weed management and can minimise environmental impacts related to herbicides. The aim of the present study was to identify allelochemicals of Artemisia nanschanica Krasch, a typical weed with strong allelopathic effects, that could potentially control Pedicularis kansuensis Maxim, the key pioneer weed that causes rapid degradation of alpine pastures. Gas chromatography and mass spectrometry were used to identify the compounds of six extracts from A. nanschanica. Two ethyl acetate extracts were the most effective in reducing the seed germination rate and in inhibiting seedling shoot and root growth of P. kansuensis. Three chemical compounds from the ethyl acetate extracts were identified for their allelopathic inhibitory effects, a sesquiterpene and two aromadendrene oxides, with the sesquiterpene being the most effective. The three compounds showed the best inhibitory effect through synergistic action. We concluded that the three allelochemicals of A. nanschanica, either alone or in combination, can be used to biologically control P. kansuensis in alpine pastures on the Tibetan plateau.
Are changes in Australian national primary healthcare policy likely to promote or impede equity of access? A narrative review
Authors: Fisher Matthew , Baum Fran , Kay Adrian , Friel Sharon
Published: June 2017

Significant changes have occurred in Australia’s national primary healthcare (PHC) policy over the last decade, but little assessment has been made of implications for equity. This research aimed to identify key recent changes in national PHC policy and assess implications for equity of access to PHC. Academic literature was reviewed to identify issues affecting equity of access in national PHC policy, and grey literature was also reviewed to identify significant policy changes during 2005–16 with implications for equitable access. Equity implications of four areas of policy change, set against the existing Medicare system, were assessed. It was found that Medicare supports equitable access to general practice, but there is a risk of reduced equity under current policy settings. Four changes in PHC policy were selected as having particular implications for equity of access and these were assessed as follows: increased involvement of private health insurance presents risks for equity; equity implications of new models of coordinated care are unclear; and regional primary health organisations and current policy on Aboriginal and Torres Strait Islander health have potential equity benefits, but these will depend on further implementation.
Fall and spring grazing influence fire ignitability and initial spread in shrub steppe communities
Authors: Davies Kirk W. , Gearhart Amanda , Boyd Chad S. , Bates Jon D.
Published: June 2017

The interaction between grazing and fire influences ecosystems around the world. However, little is known about the influence of grazing on fire, in particular ignition and initial spread and how it varies by grazing management differences. We investigated effects of fall (autumn) grazing, spring grazing and not grazing on fuel characteristics, fire ignition and initial spread during the wildfire season (July and August) at five shrub steppe sites in Oregon, USA. Both grazing treatments decreased fine fuel biomass, cover and height, and increased fuel moisture, and thereby decreased ignition and initial spread compared with the ungrazed treatment. However, effects differed between fall and spring grazing. The probability of initial spread was 6-fold greater in the fall-grazed compared with the spring-grazed treatment in August. This suggests that spring grazing may have a greater effect on fires than fall grazing, likely because fall grazing does not influence the current year’s plant growth. Results of this study also highlight that the grazing–fire interaction will vary by grazing management. Grazing either the fall or spring before the wildfire season reduces the probability of fire propagation and, thus, grazing is a potential fuel management tool.
Secular rise in economically valuable personality traits
Authors: Jokela Markus , Pekkarinen Tuomas , Sarvimäki Matti , Terviö Marko , Uusitalo Roope
Published: June 2017

Significance

The secular rise in intelligence across birth cohorts is one of the most widely documented facts in psychology. This finding is important because intelligence is a key predictor of many outcomes such as education, occupation, and income. Although noncognitive skills may be equally important, there is little evidence on the long-term trends in noncognitive skills due to lack of data on consistently measured noncognitive skills of representative populations of successive cohorts. Using test score data based on an unchanged test taken by the population of Finnish military conscripts, we find steady positive trends in personality traits that are associated with high income. These trends are similar in magnitude and economic importance to the simultaneous rise in intelligence.
Future of fundamental discovery in US biomedical research
Authors: Levitt Michael , Levitt Jonathan M.
Published: June 2017

Significance

Innovative fundamental basic science research is traditionally done by young people. This makes the steady fall in the number of younger US basic scientists a serious concern. Our analysis suggests that this happened mainly due to a bias against younger applicants, with more money going to older principal investigators (PIs). We also find a large number of postdoctoral scholars and research associates, a rapid rise in number of PIs over 71, and a steady shift of NIH funds away from R01 grants. NIH is attempting to deal with some of these issues.
Whole-organism cellular gene-expression atlas reveals conserved cell types in the ventral nerve cord of
Platynereis dumerilii
Authors: Vergara Hernando Martínez , Bertucci Paola Yanina , Hantz Peter , Tosches Maria Antonietta , Achim Kaia , Vopalensky Pavel , Arendt Detlev
Published: June 2017

The comparative study of cell types is a powerful approach toward deciphering animal evolution. To avoid selection biases, however, comparisons ideally involve all cell types present in a multicellular organism. Here, we use image registration and a newly developed “Profiling by Signal Probability Mapping” algorithm to generate a cellular resolution 3D expression atlas for an entire animal. We investigate three-segmented young worms of the marine annelid
Platynereis dumerilii
, with a rich diversity of differentiated cells present in relatively low number. Starting from whole-mount expression images for close to 100 neural specification and differentiation genes, our atlas identifies and molecularly characterizes 605 bilateral pairs of neurons at specific locations in the ventral nerve cord. Among these pairs, we identify sets of neurons expressing similar combinations of transcription factors, located at spatially coherent anterior-posterior, dorsal-ventral, and medial-lateral coordinates that we interpret as cell types. Comparison with motor and interneuron types in the vertebrate neural tube indicates conserved combinations, for example, of cell types cospecified by Gata1/2/3 and Tal transcription factors. These include V2b interneurons and the central spinal fluid-contacting Kolmer-Agduhr cells in the vertebrates, and several neuron types in the intermediate ventral ganglionic mass in the annelid. We propose that Kolmer-Agduhr cell-like mechanosensory neurons formed part of the mucociliary sole in protostome-deuterostome ancestors and diversified independently into several neuron types in annelid and vertebrate descendants.