bluuebunny/crossref_metadata_2025 huggingface dataset:
Atomic structure and domain wall pinning in samarium-cobalt-based permanent magnets
Authors: Duerrschnabel M. , Yi M. , Uestuener K. , Liesegang M. , Katter M. , Kleebe H.-J. , Xu B. , Gutfleisch O. , Molina-Luna L.
Published: June 2017

A higher saturation magnetization obtained by an increased iron content is essential for yielding larger energy products in rare-earth Sm2Co17-type pinning-controlled permanent magnets. These are of importance for high-temperature industrial applications due to their intrinsic corrosion resistance and temperature stability. Here we present model magnets with an increased iron content based on a unique nanostructure and -chemical modification route using Fe, Cu, and Zr as dopants. The iron content controls the formation of a diamond-shaped cellular structure that dominates the density and strength of the domain wall pinning sites and thus the coercivity. Using ultra-high-resolution experimental and theoretical methods, we revealed the atomic structure of the single phases present and established a direct correlation to the macroscopic magnetic properties. With further development, this knowledge can be applied to produce samarium cobalt permanent magnets with improved magnetic performance.
Yeast Cip1 is activated by environmental stress to inhibit Cdk1–G1 cyclins via Mcm1 and Msn2/4
Authors: Chang Ya-Lan , Tseng Shun-Fu , Huang Yu-Ching , Shen Zih-Jie , Hsu Pang-Hung , Hsieh Meng-Hsun , Yang Chia-Wei , Tognetti Silvia , Canal Berta , Subirana Laia , Wang Chien-Wei , Chen Hsiao-Tan , Lin Chi-Ying , Posas Francesc , Teng Shu-Chun
Published: June 2017

Upon environmental changes, proliferating cells delay cell cycle to prevent further damage accumulation. Yeast Cip1 is a Cdk1 and Cln2-associated protein. However, the function and regulation of Cip1 are still poorly understood. Here we report that Cip1 expression is co-regulated by the cell-cycle-mediated factor Mcm1 and the stress-mediated factors Msn2/4. Overexpression of Cip1 arrests cell cycle through inhibition of Cdk1–G1 cyclin complexes at G1 stage and the stress-activated protein kinase-dependent Cip1 T65, T69, and T73 phosphorylation may strengthen the Cip1and Cdk1–G1 cyclin interaction. Cip1 accumulation mainly targets Cdk1–Cln3 complex to prevent Whi5 phosphorylation and inhibit early G1 progression. Under osmotic stress, Cip1 expression triggers transient G1 delay which plays a functionally redundant role with another hyperosmolar activated CKI, Sic1. These findings indicate that Cip1 functions similarly to mammalian p21 as a stress-induced CDK inhibitor to decelerate cell cycle through G1 cyclins to cope with environmental stresses.
Data analytics using canonical correlation analysis and Monte Carlo simulation
Authors: Rickman Jeffrey M. , Wang Yan , Rollett Anthony D. , Harmer Martin P. , Compson Charles
Published: June 2017

A canonical correlation analysis is a generic parametric model used in the statistical analysis of data involving interrelated or interdependent input and output variables. It is especially useful in data analytics as a dimensional reduction strategy that simplifies a complex, multidimensional parameter space by identifying a relatively few combinations of variables that are maximally correlated. One shortcoming of the canonical correlation analysis, however, is that it provides only a linear combination of variables that maximizes these correlations. With this in mind, we describe here a versatile, Monte-Carlo based methodology that is useful in identifying non-linear functions of the variables that lead to strong input/output correlations. We demonstrate that our approach leads to a substantial enhancement of correlations, as illustrated by two experimental applications of substantial interest to the materials science community, namely: (1) determining the interdependence of processing and microstructural variables associated with doped polycrystalline aluminas, and (2) relating microstructural decriptors to the electrical and optoelectronic properties of thin-film solar cells based on CuInSe2 absorbers. Finally, we describe how this approach facilitates experimental planning and process control.
Genetic association analysis of the RTK/ERK pathway with aggressive prostate cancer highlights the potential role of CCND2 in disease progression
Authors: Chen Yang , Zhang Qin , Wang Qiuyan , Li Jie , Sipeky Csilla , Xia Jihan , Gao Ping , Hu Yanling , Zhang Haiying , Yang Xiaobo , Chen Haitao , Jiang Yonghua , Yang Yuehong , Yao Ziting , Chen Yinchun , Gao Yong , Tan Aihua , Liao Ming , Schleutker Johanna , Xu Jianfeng , Sun Yinghao , Wei Gong-Hong , Mo Zengnan
Published: June 2017

The RTK/ERK signaling pathway has been implicated in prostate cancer progression. However, the genetic relevance of this pathway to aggressive prostate cancer at the SNP level remains undefined. Here we performed a SNP and gene-based association analysis of the RTK/ERK pathway with aggressive prostate cancer in a cohort comprising 956 aggressive and 347 non-aggressive cases. We identified several loci including rs3217869/CCND2 within the pathway shown to be significantly associated with aggressive prostate cancer. Our functional analysis revealed a statistically significant relationship between rs3217869 risk genotype and decreased CCND2 expression levels in a collection of 119 prostate cancer patient samples. Reduced expression of CCND2 promoted cell proliferation and its overexpression inhibited cell growth of prostate cancer. Strikingly, CCND2 downregulation was consistently observed in the advanced prostate cancer in 18 available clinical data sets with a total amount of 1,095 prostate samples. Furthermore, the lower expression levels of CCND2 markedly correlated with prostate tumor progression to high Gleason score and elevated PSA levels, and served as an independent predictor of biochemical relapse and overall survival in a large cohort of prostate cancer patients. Together, we have identified an association of genetic variants and genes in the RTK/ERK pathway with prostate cancer aggressiveness, and highlighted the potential importance of CCND2 in prostate cancer susceptibility and tumor progression to metastasis.
Identifying affective personality profiles: A latent profile analysis of the Affective Neuroscience Personality Scales
Authors: Orri Massimiliano , Pingault Jean-Baptiste , Rouquette Alexandra , Lalanne Christophe , Falissard Bruno , Herba Catherine , Côté Sylvana M. , Berthoz Sylvie
Published: June 2017

Based on evolutionary theory, a recent model in affective neuroscience delineated six emotional brain systems at the core of human personality: SEEKING, CARING, PLAYFULNESS, FEAR, ANGER, SADNESS. The Affective Neuroscience Personality Scales (ANPS) assess their functioning. Using a person-centred approach of the ANPS, this study: (i) examined the existence of latent personality profiles, (ii) studied their gender invariance, (iii) assessed their longitudinal (4 years) stability, and (iv) explored how they relate to several intrapersonal, interpersonal, and emotion regulation skills. Latent Profile Analysis in 2 samples (Canadian, longitudinal, N = 520; French, cross-sectional, N = 830) found that, qualitatively, 3 profiles characterized both populations and genders, with one distinction for the second profile where the French women endorsed slightly higher and lower scores for, respectively, the negative and positive emotions. Whilst not being quantitatively similar across genders, the personality profiles remained consistent across time in the longitudinal sample. Associations between profiles and intrapersonal (e.g. depression), interpersonal (e.g. empathy), and emotion regulation skills measures (e.g. emotional intelligence) offered concurrent validity evidence. This person centred approach to ANPS offers a holistic and parsimonious way to study affective personality dimensions. It opens promising avenues for future studies on the predictive value of ANPS profiles, and for personality-targeted interventions.
Improving biodiversity assessment via unsupervised separation of biological sounds from long-duration recordings
Authors: Lin Tzu-Hao , Fang Shih-Hua , Tsao Yu
Published: June 2017

Investigating the dynamics of biodiversity via passive acoustic monitoring is a challenging task, owing to the difficulty of identifying different animal vocalizations. Several indices have been proposed to measure acoustic complexity and to predict biodiversity. Although these indices perform well under low-noise conditions, they may be biased when environmental and anthropogenic noises are involved. In this paper, we propose a periodicity coded non-negative matrix factorization (PC-NMF) for separating different sound sources from a spectrogram of long-term recordings. The PC-NMF first decomposes a spectrogram into two matrices: spectral basis matrix and encoding matrix. Next, on the basis of the periodicity of the encoding information, the spectral bases belonging to the same source are grouped together. Finally, distinct sources are reconstructed on the basis of the cluster of the basis matrix and the corresponding encoding information, and the noise components are then removed to facilitate more accurate monitoring of biological sounds. Our results show that the PC-NMF precisely enhances biological choruses, effectively suppressing environmental and anthropogenic noises in marine and terrestrial recordings without a need for training data. The results may improve behaviour assessment of calling animals and facilitate the investigation of the interactions between different sound sources within an ecosystem.
Response of Atlantic salmon Salmo salar to temperature and dissolved oxygen extremes established using animal-borne environmental sensors
Authors: Stehfest Kilian M. , Carter Chris G. , McAllister Jaime D. , Ross Jeff D. , Semmens Jayson M.
Published: June 2017

Understanding how aquatic species respond to extremes of DO and temperature is crucial for determining how they will be affected by climate change, which is predicted to increasingly expose them to levels beyond their optima. In this study we used novel animal-borne DO, temperature and depth sensors to determine the effect of extremes of DO and temperature on the vertical habitat use of Atlantic salmon Salmo salar in aquaculture cages. Salmon showed a preference for temperatures around 16.5 to 17.5 °C, however, selection of preferred temperatures was trumped by active avoidance of low DO (<35% saturation) at the bottom of the cage. In addition to low DO, salmon also avoided warm surface waters (>20.1 °C), which led to a considerable contraction in the available vertical habitat. Despite their avoidance behavior, fish spent a large amount of time in waters with suboptimal DO (<60% saturation). These results show that vertical habitat contraction could likely be a significant consequence of climate change if the reduction in DO outpaces the increase in hypoxia tolerance through local adaptation. They furthermore highlight that site-specific environmental conditions and stock-specific tolerance thresholds may need to be considered when determining stocking densities.
Comparative transcriptome analysis on the synthesis pathway of honey bee (Apis mellifera) mandibular gland secretions
Authors: Wu YuQi , Zheng HuoQing , Corona Miguel , Pirk Christian , Meng Fei , Zheng YuFei , Hu FuLiang
Published: June 2017

Secretions from mandibular glands (MGs) have important caste-specific functions that are associated with the social evolution of honey bees. To gain insights into the molecular architecture underlying these caste differences, we compared the gene expression patterns of MGs from queens, queenright workers (WQRs) and queenless workers (WQLs) using high-throughput RNA-sequencing technology. In total, we identified 46 candidate genes associated with caste-specific biosynthesis of fatty acid pheromones in the MG, including members of cytochrome P450 (CYP450) family and genes involved in fatty acid β-oxidation and ω-oxidation. For further identification of the CYP450s genes involved in the biosynthesis of MG secretions, we analyzed by means of qPCR, the expression levels of six of the CYP450 genes most abundantly expressed in the transcriptome analysis across different castes, ages, tasks and tissues. Our analysis revealed that CYP6AS8 and CYP6AS11, the most abundantly expressed CYP450 genes in worker and queen MGs, respectively, are selectively expressed in the MGs of workers and queens compared to other tissues. These results suggest that these genes might be responsible for the critical bifurcated hydroxylation process in the biosynthesis pathway. Our study contributes to the description of the molecular basis for the biosynthesis of fatty acid-derived pheromones in the MGs.
Non-activation MOF arrays as a coating layer to fabricate a stable superhydrophobic micro/nano flower-like architecture
Authors: Zhang Guoliang , Zhang Jiaheng , Su Pengcheng , Xu Zehai , Li Wanbin , Shen Chong , Meng Qin
Published: June 2017

Non-activation metal–organic framework (MOF) arrays are directly applied as a coating layer to fabricate a stable superhydrophobic micro/nano flower-like architecture.
Transition metal-free, visible-light mediated synthesis of 1,10-phenanthroline derived ligand systems
Authors: Edwards Alyn C. , Geist Andreas , Müllich Udo , Sharrad Clint A. , Pritchard Robin G. , Whitehead Roger C. , Harwood Laurence M.
Published: June 2017

An efficient, visible-light mediated, mild and metal-free strategy for the direct α- and γ-functionalisation of 1,10-phenanthrolines is reported.
Investigation into the structural features and microwave absorption of doped barium hexaferrites
Authors: Trukhanov S. V. , Trukhanov A. V. , Kostishyn V. G. , Panina L. V. , Trukhanov An. V. , Turchenko V. A. , Tishkevich D. I. , Trukhanova E. L. , Yakovenko O. S. , Matzui L. Yu.
Published: June 2017

BaFe12−xGaxO19 hexaferrites were synthesized via the usual ceramic technology; with an increase in x, the unit cell and magnetic parameters monotonically decrease.
Photoluminescent-dielectric duple switch in a perovskite-type high-temperature phase transition compound: [(CH3)3PCH2OCH3][PbBr3]
Authors: Geng Fu-Juan , Wu De-Hong , Zhou Lin , Shi Ping-Ping , Li Peng-Fei , Gao Ji-Xing , Zheng Xuan , Fu Da-Wei , Ye Qiong
Published: June 2017

A perovskite-type high-temperature phase transition compound, ([(CH3)3PCH2OCH3][PbBr3], 1), displays a remarkable bistable photoluminescent-dielectric duple switching behavior.
Identification of perturbed signaling pathways from gene expression data using information divergence
Authors: Hu Xinying , Wei Hang , Zheng Haoran
Published: June 2017

We propose a pathway analysis method based on information divergence and the probability distribution of the regulation capacity.
Low pH-triggering changes in peptide secondary structures
Authors: Furukawa Kaori , Oba Makoto , Toyama Kotomi , Opiyo George Ouma , Demizu Yosuke , Kurihara Masaaki , Doi Mitsunobu , Tanaka Masakazu
Published: June 2017

An acidic treatment of cyclic α,α-disubstituted α-amino acid-containing peptides changes their conformation from a helical to a random structure.
Preparation of transparent monolithic methylsilsesquioxane (MSQ) aerogels via ambient pressure drying
Authors: Zhang Tao , Yuan Hua , Wang Shuangqing , Guo Xudong , Hu Rui , Li Yi , Yang Guoqiang
Published: June 2017

Transparent monolithic MSQ aerogels were prepared by an ambient pressure drying method. The obtained hydrophobic aerogels showed good stability to various aggressive environments.
Bisphenol A exposure triggers apoptosis via three signaling pathways in Caenorhabditis elegans
Authors: Wang Yun , Zhang Lianfeng , Luo Xun , Wang Shunchang , Wang Yuanyuan
Published: June 2017

Bisphenol A can trigger germline apoptosisviathree signaling pathways including DNA damage response (DDR) pathway, mitogen-activated protein kinase (MAPK) cascades and insulin-like growth factor-1 (IGF-1) network inCaenorhabditis elegans.
Synthesizing nonstoichiometric Li3−3xV2+x(PO4)3/C as cathode materials for high-performance lithium-ion batteries by solid state reaction
Authors: Sun Pingping , Su Ningang , Wang Yuanting , Xu Qingyu , Fan Qi , Sun Yueming
Published: June 2017

A simple solid state reaction method has been developed to synthesize nonstoichiometric Li3−3xV2+x(PO4)3/C (x = 0–0.15) nanocomposites.
Improved thermoelectric power factor and conversion efficiency of perovskite barium stannate
Authors: Li Jun , Ma Zuju , Sa Rongjian , Wu Kechen
Published: June 2017

The highly dispersive conduction band and high temperature stability contribute to the excellent electrical properties when BaSnO3 is n-type doped.
Influence of carbonization temperature and press processing on the electrochemical characteristics of self-standing iron oxide/carbon composite electrospun nanofibers
Authors: Abe J. , Kawase K. , Tachikawa N. , Katayama Y. , Shiratori S.
Published: June 2017

Schematic illustration of self-standing active material composite carbon nanofibrous electrodes for lithium ion battery applications.
2D material integrated macroporous electrodes for Li-ion batteries
Authors: Gullapalli Hemtej , Kalaga Kaushik , Vinod Soumya , Rodrigues Marco-Tulio F. , George Antony , Ajayan Pulickel M.
Published: June 2017

One-step synthesized graphene covered three-dimensionally structured architectures are found to be able current collectors in improving the performance of electrodes used in Li ion battery systems.
Enhanced mechanical properties of Nylon6 nanocomposites containing pristine α-zirconium phosphate nanoplatelets of various sizes by melt-compounding
Authors: Zhang He , Chen Lei , Han Xiao , Jiang Feng , Sun Haoyang , Sun Dazhi
Published: June 2017

Nylon6 nanocomposites containing pristine layered α-zirconium phosphate (ZrP) nanoplatelets of various sizes have been fabricated by a simple and direct melt-compounding method without adding intercalation or exfoliation agents.
Electricity generation in a microbial fuel cell using yogurt wastewater under alkaline conditions
Authors: Luo Haiping , Xu Guofang , Lu Yaobin , Liu Guangli , Zhang Renduo , Li Xiao , Zheng Xiyuan , Yu Meihan
Published: June 2017

The MFC could generate electricity using yogurt wastewater as the substrate under pH = 10.5.
Multilayer hierarchical interfaces with high energy density in polymer nanocomposites composed of BaTiO3@TiO2@Al2O3 nanofibers
Authors: Pan Zhongbin , Zhai Jiwei , Shen Bo
Published: June 2017

Nanocomposite films with small loading of BaTiO3@TiO2@Al2O3 nanofibers show a high energy density of 14.84 J cm−3 at 450 MV m−1 and an ultra-fast discharge speed of 0.37 μs.
Fluoride-sulfophosphate glasses as hosts for broadband optical amplification through transition metal activators
Authors: Wang W. C. , Le Q. H. , Zhang Q. Y. , Wondraczek L.
Published: June 2017

Unusually stable multi-anion glasses of the fluoride-sulfophosphate type (FPS) are introduced as a new host material for optically active cation species.
Fluorination in thieno[3,4-c]pyrrole-4,6-dione copolymers leading to electron transport, high crystallinity and end-on alignment
Authors: Weller T. , Breunig M. , Mueller C. J. , Gann E. , McNeill C. R. , Thelakkat M.
Published: June 2017

GIWAXS measurements confirm end-on alignment for TPD-copolymers obtained from Stille polycondensation using fluorinated and non-fluorinated comonomers.
Self-Rated Communication-Related Quality of Life of Individuals With Oromandibular Dystonia Receiving Botulinum Toxin Injections
Authors: Page Allyson D. , Siegel Lauren , Jog Mandar
Published: June 2017

Purpose

In this preliminary study, we examined self-rated communication-related quality of life (CR-QoL) of 10 control participants and 10 individuals with oromandibular dystonia (OMD) and dysarthria receiving therapeutic botulinum toxin (BoNT-A) injections.

Method

Participants with OMD and associated dysarthria self-rated CR-QoL pre- and post- BoNT-A injection using the American Speech-Language-Hearing Association's Quality of Communication Life Scale (ASHA QCL; Paul et al., 2004). Control participants self-rated CR-QoL during a single experimental visit.

Results

Significant differences were found between control participants and participants with OMD on ratings of CR-QoL across all 5 domains and subdomains of the ASHA QCL. No significant differences in CR-QoL were found over the course of the BoNT-A treatment cycle.

Conclusions

CR-QoL was rated lower by participants with OMD as compared with control participants across all ASHA QCL domains/subdomains with “socialization/activities” and “confidence/self-concept” having the largest effect sizes. No differences in CR-QoL were found over the course of the treatment cycle. We advocate for outcome measures that include patient report. The use of patient-reported outcome measures in conjunction with objective or impairment-based outcome measures can help inform meaningful clinical indicators of treatment success. This study adds novel information that may aid our understanding of the experience of living with OMD in this underserviced clinical population.
Internally Versus Externally Cued Speech in Parkinson's Disease and Cerebellar Disease
Authors: Weir-Mayta Phil , Spencer Kristie A. , Eadie Tanya L. , Yorkston Kathryn , Savaglio Sara , Woollcott Chris
Published: June 2017

Purpose

The purpose of this study was to examine the effects of an internally versus externally cued speech task on perceived understandability and naturalness in speakers with Parkinson's disease (PD) and cerebellar disease (CD).

Method

Sentences extracted from a covertly recorded conversation (internally cued) were compared to the same sentences read aloud (externally cued) by speakers with PD and a clinical comparison group of speakers with CD. Experienced listeners rated the speech samples using a visual analog scale for the perceptual dimensions of understandability and naturalness.

Results

Results suggest that experienced listeners rated the speech of participants with PD as significantly more natural and more understandable during the reading condition. Participants with CD were also rated as significantly more understandable during the reading condition, but ratings of naturalness did not differ between conversation and reading.

Conclusions

Speech tasks can have a pronounced impact on perceived speech patterns. For individuals with PD, both understandability and naturalness can improve during reading tasks versus conversational tasks. The speech benefits from reading may be attributed to several mechanisms, including possible improvement from an externally cued speech task. These findings have implications for speech task selection in evaluating individuals with dysarthria.
Initial Observations of Lingual Movement Characteristics of Children With Cerebral Palsy
Authors: Nip Ignatius S. B. , Arias Carlos R. , Morita Kristen , Richardson Hannah
Published: June 2017

Purpose

This preliminary study compared the speech motor control of the tongue and jaw between children with cerebral palsy (CP) and their typically developing (TD) peers.

Method

Tongue tip and jaw movements of 4 boys with spastic CP and 4 age- and sex-matched TD peers were recorded using an electromagnetic articulograph during 10 repetitions of “Dad told stories today.” The duration, path distance, average speed, and speech movement stability of the movements were calculated for each repetition.

Results

The children with CP had longer durations than their TD peers. Children with CP had longer path distances and faster average speed as compared with their TD peers for both articulators. The TD group but not the CP group had longer path distances and faster average speeds for the tongue than the jaw. The CP group had reduced speech movement stability for the tongue as compared with their TD peers, but both groups had similar speech movement stability for the jaw.

Conclusions

Children with CP had impaired speech motor control of the tongue and jaw as compared with their TD peers, and these speech motor control deficits were more pronounced in the tongue tip than the jaw.
Easy Access to Quinolin-2(1H)-ones via a One-Pot Tandem Oxa-Michael–Aldol Sequence
Authors: Jarrige Lucie , Merad Jeremy , Zaied Siwar , Blanchard Florent , Masson Géraldine
Published: June 2017

An efficient strategy for the synthesis of a variety of quinolin-2(1H)-one derivatives has been developed. The reaction proceeded from cinnamide derivatives via a tandem reaction in the presence of NaOH to afford the corresponding 2- quinolin-2(1H)-one derivatives in good to excellent yields.
Impact of Acute Intestinal Ischemia and Reperfusion Injury on Hemodynamics and Remote Organs in a Rat Model
Authors: Wang Meng , Verhaegh Rabea , Tsagakis Konstantinos , Brencher Lisa , Zwanziger Denise , Jakob Heinz , Groot Herbert , Dohle Daniel-Sebastian
Published: June 2017

Background Acute mesenteric ischemia following cardiovascular surgery is a rare but fatal complication. We established a new rat model for hemodynamic monitoring during mesenteric ischemia/reperfusion (I/R) and evaluated the impact of mesenteric I/R on hemodynamics and remote organ injury.

Methods Mesenteric I/R was induced in male Wistar rats by superior mesenteric artery occlusion for 90 minutes, followed by 120 minutes of reperfusion. Before I/R, ventilation and hemodynamic monitoring including mean arterial blood pressure (MAP) and cardiac output (CO) were established. During reperfusion Geloplasma (I/R + Geloplasma, N = 6) and Ringer's solution (I/R + Ringer, N = 6) were titrated according to CO and compared with I/R without volume resuscitation (I/R only, N = 6) and a sham group (sham, N = 6). Blood samples were regularly taken for serum marker measurements. After reperfusion organs were harvested for histology studies.

Results After acute mesenteric I/R, MAP and CO decreased (p < 0.01) while systemic and pulmonary vascular resistance increased (p < 0.01) continuously in the I/R group. Volume substitution according to CO initially stabilized hemodynamic parameters, but CO declined independently in the late stage. Compared with the I/R + Ringer group, the I/R + Geloplasma group required less volume for resuscitation (p < 0.01), experienced less metabolic acidosis. I/R groups had more organ injuries, more neutrophils sequestration, and higher creatine phosphokinase-MB levels than sham group.

Conclusion A new model for CO monitoring after mesenteric I/R injury demonstrated severe hypovolemic shock during reperfusion followed by remote myocardial and lung injury. Far less colloid volume is needed for hemodynamic stabilization after I/R compared with crystalloid volume.
Impact of electrode geometry on an atmospheric pressure surface barrier discharge
Authors: Hasan M. I. , Morabit Y. , Dickenson A. , Walsh J. L.
Published: June 2017

Several of the key characteristics of an atmospheric pressure surface barrier discharge (SBD) are heavily dependent on the geometrical configuration of the plasma generating electrodes. This paper reveals that increasing the surface area of an SBD device by reducing the gaps within the electrodes can have major and unforeseen consequence on the discharge properties. It is experimentally demonstrated that a critical limit exists when reducing the diameter of a circular electrode gap below 5 mm, beyond which the required breakdown voltage increases exponentially and the power deposited in the discharge is impeded. Using a numerical model, it is shown that a reduced electrode gap diameter yields a decrease in the voltage difference between the electrode and dielectric surface, thus lowering the maximum electric field. This study indicates a link between the electrode geometry and the nature of the reactive chemistry produced in the plasma, findings which have wide-reaching implications for many applications where multiple closely packed surface barrier discharges are employed to achieve uniform and large area plasma processing.
Nonreciprocity and one-way topological transitions in hyperbolic
metamaterials
Authors: Leviyev A. , Stein B. , Christofi A. , Galfsky T. , Krishnamoorthy H. , Kuskovsky I. L. , Menon V. , Khanikaev A. B.
Published: June 2017

Control of the electromagnetic waves in nano-scale structured materials is crucial to the development of next generation photonic circuits and devices. In this context, hyperbolic metamaterials, where elliptical isofrequency surfaces are morphed into surfaces with exotic hyperbolic topologies when the structure parameters are tuned, have shown unprecedented control over light propagation and interaction. Here we show that such topological transitions can be even more unusual when the hyperbolic metamaterial is endowed with nonreciprocity. Judicious design of metamaterials with reduced spatial symmetries, together with the breaking of time-reversal symmetry through magnetization, is shown to result in nonreciprocal dispersion and one-way topological phase transitions in hyperbolic metamaterials.
Two-fluid tearing mode instability in cylindrical geometry
Authors: Ito Atsushi , Ramos Jesús J.
Published: June 2017

This paper investigates the linear stability of a force-free equilibrium in a plasma cylinder of finite aspect ratio, against the two-fluid resistive tearing mode. An analytic dispersion relation is derived by extending to cylindrical geometry the slab geometry boundary layer theory applicable to two-fluid tearing modes for high beta and general ion skin depths [E. Ahedo and J. J. Ramos, Plasma Phys. Controlled Fusion 51, 055018 (2009)]. The cylindrical dispersion relation shows the dependence of the mode growth rate and real frequency on the ion skin depth, through different regimes that range from the single-fluid MHD limit to the electron MHD limit. It also shows that the non-zero real frequency of the mode arises due to the combination of two-fluid and cylindrical effects. A numerical solution of the complete set of normal-mode equations that resolves the fine-scale singular layer is carried out, for a wide range of resistivity and ion skin depth values. The numerically obtained eigenvalues agree very well with the analytic dispersion relation and the agreement improves the smaller the resistivity and the larger the ion skin depth are. Comparison between the numerical eigenfunctions and the inner solutions of the boundary layer theory shows that the eigenfunctions develop imaginary parts within the resonant layer, also due to the combination of two-fluid and cylindrical effects.
Estimating two-point statistics from derivatives of a signal containing noise: Application to auto-correlation functions of turbulent Lagrangian tracks
Authors: Machicoane N. , Huck P. D. , Volk R.
Published: June 2017

This article describes a method for calculating moments and correlation functions of signal derivatives, which were rid of experimental noise without the use of filtering operations. The method is based on the computation of the ensemble-average of different time (or spatial) increments of the signal. The hypotheses are that the noise is white and not correlated with the signal; however, the method is also shown to work with colored noise. The method is first developed, considering white noise, and benchmarked with synthetic trajectories containing noise with variable signal-to-noise ratios. It is then tested on experimental trajectories in the context of Lagrangian tracking of particles in turbulent flows, either containing a short-correlated noise or a colored noise.
Random scalar fields and hyperuniformity
Authors: Ma Zheng , Torquato Salvatore
Published: June 2017

Disordered many-particle hyperuniform systems are exotic amorphous states of matter that lie between crystals and liquids. Hyperuniform systems have attracted recent attention because they are endowed with novel transport and optical properties. Recently, the hyperuniformity concept has been generalized to characterize two-phase media, scalar fields, and random vector fields. In this paper, we devise methods to explicitly construct hyperuniform scalar fields. Specifically, we analyze spatial patterns generated from Gaussian random fields, which have been used to model the microwave background radiation and heterogeneous materials, the Cahn-Hilliard equation for spinodal decomposition, and Swift-Hohenberg equations that have been used to model emergent pattern formation, including Rayleigh-Bénard convection. We show that the Gaussian random scalar fields can be constructed to be hyperuniform. We also numerically study the time evolution of spinodal decomposition patterns and demonstrate that they are hyperuniform in the scaling regime. Moreover, we find that labyrinth-like patterns generated by the Swift-Hohenberg equation are effectively hyperuniform. We show that thresholding (level-cutting) a hyperuniform Gaussian random field to produce a two-phase random medium tends to destroy the hyperuniformity of the progenitor scalar field. We then propose guidelines to achieve effectively hyperuniform two-phase media derived from thresholded non-Gaussian fields. Our investigation paves the way for new research directions to characterize the large-structure spatial patterns that arise in physics, chemistry, biology, and ecology. Moreover, our theoretical results are expected to guide experimentalists to synthesize new classes of hyperuniform materials with novel physical properties via coarsening processes and using state-of-the-art techniques, such as stereolithography and 3D printing.
Outer midplane scrape-off layer profiles and turbulence in simulations of Alcator C-Mod inner-wall limited discharges
Authors: Halpern Federico D. , LaBombard Brian , Terry James L. , Zweben Stewart J.
Published: June 2017

A region of steep plasma gradients, the so-called “narrow-feature,” has been found in the near scrape-off layer (SOL) of inner-wall limited (IWL) discharges. Dedicated IWL discharges were carried out in Alcator C-Mod [Marmar et al., Nucl. Fusion 55, 104020 (2015)] to study this phenomenon, allowing detailed observations of the plasma profiles and fluctuations. Langmuir probe (LP) measurements show a clear two-decay length ne and Te profile structure at the outer midplane. The Gas-Puff Imaging (GPI) diagnostic shows large turbulent fluctuations across the last closed flux-surface, hence supporting the hypothesis that turbulent phenomena play a role in setting the profile steepness. Flux-driven non-linear turbulence simulations of two C-Mod discharges have been carried out, allowing a three-way comparison between LP, GPI, and simulation data. Observations and simulations correlate the steep gradient region characterizing the narrow feature with sheared poloidal flows and a deviation of the plasma potential from its floating value. The E × B shear rate exceeds the linear ballooning growth rate, indicating that the narrow feature could result from the effects of sheared flows, although causality could not be established. The fluctuation level in the narrow feature remains of order unity across the entire SOL, indicating that the transport reduction in the near-SOL cannot result from a simple quench rule.
A novel measurand independent of the distance between the source and detector for continuous wave near-infrared spectroscopy
Authors: Kiguchi Masashi , Funane Tsukasa , Sato Hiroki
Published: June 2017

A new measurand is proposed for use in continuous wave near-infrared spectroscopy (cw-NIRS). The conventional measurand of cw-NIRS is l△c, which is the product of the change in the hemoglobin concentration (△c) and the partial path lengh (l), which depends on the source-detector (SD) distance (d). The SD distance must remain constant during cw-NIRS measurements, and we cannot compare the l△c value with that obtained using a different SD distance. In addition, the conventional measurand obtained using the standard measurement style sometimes includes a contribution from the human scalp. The SD distance independent (SID) measurand obtained using multi-SD distances is proportional to the product of the change in hemoglobin concentration and the derivative of the partial path length for the deep region with no scalp contribution under the assumption of a layer model. The principle of SID was validated by the layered phantom study. In order to check the limitation of assumption, a human study was conducted. The value of the SID measurand for the left side of the forehead during working memory task was approximately independent of the SD distance between 16 and 32 mm. The SID measurand and the standardized optode arrangement using flexible SD distances in a head coordinate system must be helpful for comparing the data in a population study.
Excitonic complexes in strain-free and highly symmetric GaAs quantum dots fabricated by filling of self-assembled nanoholes
Authors: Trabelsi Z. , Yahyaoui M. , Boujdaria K. , Chamarro M. , Testelin C.
Published: June 2017

We perform a theoretical study of the optical transitions for different excitonic complexes in highly symmetric strain-free GaAs quantum dots (QDs) fabricated by epitaxially filling nanoholes (NHs) in an AlGaAs surface. NHs are formed by local droplet etching. As a first step, we propose a QD shape modeling consistent with atomic force microscopy (AFM) profiles and an experimental growth procedure. We investigate the QD height dependence of s- and p- shell exciton recombination energies in the framework of the effective mass approximation with an exact numerical diagonalization method. A comparison between theoretical results and available spectroscopic data is carried out. Systematic evolution of the binding energies of neutral (X), charged excitons (X–, X+) and the biexciton (XX), with QD height, is interpreted in terms of a balance between the Coulomb interactions and charge carrier correlation effects. Our calculations demonstrate the important role of the correlation energies in elucidating the bound character of all few-particle states especially the biexciton.
Use of a bilayer lattice-matched AlInGaN barrier for improving the channel carrier confinement of enhancement-mode AlInGaN/GaN hetero-structure field-effect transistors
Authors: Rahbardar Mojaver Hassan , Gosselin Jean-Lou , Valizadeh Pouya
Published: June 2017

A quaternary lattice-matched layer structure based on employing a bilayer barrier for improving the carrier confinement in the channel of enhancement-mode metal-face c-plane wurtzite AlInGaN/GaN hetero-structure field effect transistors (HFETs) is for the first time proposed. Using the commercial self-consistent Poisson-Schrödinger solver Nextnano, electronic properties of the proposed hetero-structure, including the sheet charge density and carrier confinement on the GaN side of the hetero-interface, are evaluated. Based on these evaluations, it is shown that while the proposed layer structure substantially improves the carrier confinement in the GaN channel layer, it also upholds the merits of employing a lattice-matched barrier towards achieving an enhancement-mode operation (i.e., in the absence of the piezoelectric effect). According to these simulations, in terms of maintaining the required positive threshold-voltage for the enhancement-mode operation, it is also shown that the proposed layer structure substantially outperforms the quaternary AlInGaN/GaN HFETs employing a thin AlN spacer layer.
Peeling off effects in vertically aligned Fe3C filled carbon nanotubes films grown by pyrolysis of ferrocene
Authors: Boi Filippo S. , Medranda Daniel , Ivaturi Sameera , Wang Jiayu , Guo Jian , Lan Mu , Wen Jiqiu , Wang Shanling , He Yi , Mountjoy Gavin , Willis Maureen A. C. , Xiang Gang
Published: June 2017

We report the observation of an unusual self-peeling effect which allows the synthesis of free standing vertically aligned carbon nanotube films filled with large quantities of Fe3C and small quantities of γ-Fe crystals. We demonstrate that this effect depends on the interplay of three main factors: (1) the physical interactions between the chosen substrate surface and grown carbon nanotubes (CNTs), which is fixed by the composition of the used substrate (111 SiO2/Si or quartz), (2) the CNT-CNT Van der Waals interactions, and (3) the differential thermal contraction between the grown CNT film and the used substrate, which is fixed by the cooling rate differences between the grown film and the used quartz or Si/SiO2 substrates. The width and stability of these films are then further increased to cm-scale by addition of small quantities of toluene to the ferrocene precursor.
A highly efficient element for generating elliptic perfect optical vortices
Authors: Kovalev A. A. , Kotlyar V. V. , Porfirev A. P.
Published: June 2017

We generalize the concept of perfect optical vortices, studying the elliptic perfect optical vortices (EPOVs), which also have diameters independent of the topological charge. A phase-only diffractive optical element is proposed for the efficient generation of such EPOV. The intensity of the EPOV generated by this element is higher than that of the EPOV generated approximately by an elliptical axicon. We obtain exact analytical expressions for the orbital angular momentum (OAM) density and for the total OAM of the EPOV. These expressions show that the normalized OAM of the EPOV is fractional and it exceeds the OAM of the conventional circular perfect optical vortex, which equals the topological charge. It allows continuous controlling of the OAM by changing the ellipticity. We show analytically that the OAM density is maximal on the smaller side of the EPOV. The ratio of the maximal to the minimal OAM density equals the squared ratio of the ellipse dimensions. Using the proposed element, EPOVs that carry different topological charges are generated experimentally with the aid of a spatial light modulator. We experimentally confirm the independence of their size from the topological charge, which is determined interferometrically. Such EPOVs can be used for moving microscopic particles along an ellipse with acceleration, as well as for the generation of OAM-entangled photons.
Corrugated plasmonic cavity for enhanced intersubband photodetection
Authors: Men Chuanling , Qu Ri , Cao Jun , Yu Haochi , Gou Peng , Zou Yuexin , Yang Le , Qian Jie , Zhao Ziyi , Xu Jie , An Zhenghua
Published: June 2017

We study the optical properties of a corrugated plasmonic cavity consisting of a perforated metal film and a flat metal sheet separated by a semiconductor spacer. Corrugation enhances dramatically the coupling between the propagating surface plasmon and the Fabry-Perot mode and induces Rabi-like splitting forming bright bonding and dark anti-bonding modes. The anti-bonding mode exhibits considerably higher volume-averaged field enhancement factors (∼16.5 for E-field and ∼14.1 for Ez-component) than its bonding counterpart as well as a very high polarization conversion ratio (∼85.5%) from transverse electric to transverse magnetic waves. These characteristics make the corrugation induced anti-bonding mode particularly suitable for semiconductor quantum well intersubband photodetectors. Our work may provide a general guideline to the design of metamaterial-coupled intersubband hybrid devices for practical applications.
Approach predicts reaction rate in combustion of ammonia over unprecedented temperature range
Authors: Bello Mark
Published: June 2017

Work on conditions for ammonia combustion adds to fundamental understanding of emerging fossil-fuel alternative.
Effect of periodic array on the on-state resistances of GaAs photoconductive semiconductor switch based on total reflection theory
Authors: Xiao Longfei , Hu Xiaobo , Chen Xiufang , Peng Yan , Yang Xianglong , Xu Xiangang
Published: June 2017

GaAs-based 5-mm-gap photoconductive semiconductor switches (PCSSs), with a thickness of 1 mm, are fabricated. A 60° beveling angle is used to make a periodic array of grooves on the surface of GaAs by mechanical processing. The laser beam should be reflected back when a vertical laser is illuminated on these grooves according to total internal reflection (TIR), which leads to an improvement of the light use efficiency (LUE) for the PCSS. The on-state resistance, ranging from 5.17 Ω to 2.14 Ω for the PCSSs, decreases in proportion with an increase of the duty cycle from 0% to 87.8%, where the pulse laser energy is 6.1 mJ at 1064 nm.
Novel X-ray tomography technique enables faster, non-destructive 3D imaging of nanoscale details of objects
Authors: Zhang Zhengzheng
Published: June 2017

Scientists have developed a novel SEM-based X-ray tomography system that produces nanometer resolved 3D images with significantly reduced scanning time, overcoming limitations of existing X-ray tomography systems and extending the range for 3D structural analysis of objects.
Owl survey of the Peel–Harvey Estuary in south-western Australia
Authors: Fulton Graham R.
Published: June 2017

Little is known of owls in south-western Australia compared with the owls of southern and eastern Australia. Surveys of forest owls in the south-west are almost completely lacking. This study sought to determine the abundance and detectability of owls immediately around the Peel–Harvey Estuary in south-western Australia. The southern boobook (Ninox boobook) and the masked owl (Tyto novaehollandiae) were the only owls detected (n = 23 and n = 1 respectively), although the nocturnal tawny frogmouth (Podargus strigoides) was detected from unelicited calls on three occasions. Southern boobooks were found to be common in this area though they are reported to be in decline in south-eastern and inland Australia. Their detectability was significantly greater in August (late winter) than at other times through unelicited calls; otherwise, there were no detections in winter. A variety of small mammals were detected during the surveys, including: a little red flying-fox (Pteropus scapulatus), a western ringtail possum (Pseudocheirus occidentalis), 19 southern brown bandicoots (Isoodon obesulus), 4 common brushtail possums (Trichosurus vulpecula), 21 rabbits (Oryctolagus cuniculus), a black rat (Rattus rattus), 2 red foxes (Vulpes vulpes) and 22 microbats.
Groundwater declines are linked to changes in Great Plains stream fish assemblages
Authors: Perkin Joshuah S. , Gido Keith B. , Falke Jeffrey A. , Fausch Kurt D. , Crockett Harry , Johnson Eric R. , Sanderson John
Published: June 2017

Significance

Nature and society depend on groundwater to sustain aquatic ecosystems and human livelihoods, but local and regional groundwater supplies are dwindling where human water extraction exceeds aquifer recharge. Although groundwater depletion is a global problem, ecological consequences for aquatic species such as fishes are rarely examined. We demonstrate that more than half a century of groundwater pumping from the United States High Plains Aquifer has been associated with collapses of large-stream fishes and expansion of small-stream fishes where hydrologic conditions were altered most. Projections indicate that these habitats will continue to shrink over the next half-century if groundwater pumping practices are not modified. Our findings highlight a mechanism for biotic homogenization with global implications given the worldwide extraction of groundwater.
Aridity and hominin environments
Authors: Blumenthal Scott A. , Levin Naomi E. , Brown Francis H. , Brugal Jean-Philip , Chritz Kendra L. , Harris John M. , Jehle Glynis E. , Cerling Thure E.
Published: June 2017

Significance

Oxygen isotopes in modern and fossil mammals can provide information on climate. In this study, we provide a new record of aridity experienced by early hominins in Africa. We show that past climates were similar to the climate in eastern Africa today, and that early hominins experienced highly variable climates over time. Unexpectedly, our findings suggest that the long-term expansion of grasses and grazing herbivores since the Pliocene, a major ecological transformation thought to drive aspects of hominin evolution, was not coincident with aridification in northern Kenya. This finding raises the possibility that some aspects of hominin environmental variability might have been uncoupled from aridity, and may instead be related to other factors, such as rainfall seasonality or ecological interactions among plants and mammals.