bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate and reproducible invasive breast cancer detection in whole-slide images: A Deep Learning approach for quantifying tumor extent
Authors: Cruz-Roa Angel , Gilmore Hannah , Basavanhally Ajay , Feldman Michael , Ganesan Shridar , Shih Natalie N.C. , Tomaszewski John , González Fabio A. , Madabhushi Anant
Published: April 2017

With the increasing ability to routinely and rapidly digitize whole slide images with slide scanners, there has been interest in developing computerized image analysis algorithms for automated detection of disease extent from digital pathology images. The manual identification of presence and extent of breast cancer by a pathologist is critical for patient management for tumor staging and assessing treatment response. However, this process is tedious and subject to inter- and intra-reader variability. For computerized methods to be useful as decision support tools, they need to be resilient to data acquired from different sources, different staining and cutting protocols and different scanners. The objective of this study was to evaluate the accuracy and robustness of a deep learning-based method to automatically identify the extent of invasive tumor on digitized images. Here, we present a new method that employs a convolutional neural network for detecting presence of invasive tumor on whole slide images. Our approach involves training the classifier on nearly 400 exemplars from multiple different sites, and scanners, and then independently validating on almost 200 cases from The Cancer Genome Atlas. Our approach yielded a Dice coefficient of 75.86%, a positive predictive value of 71.62% and a negative predictive value of 96.77% in terms of pixel-by-pixel evaluation compared to manually annotated regions of invasive ductal carcinoma.
TmCactin plays an important role in Gram-negative and -positive bacterial infection by regulating expression of 7 AMP genes in Tenebrio molitor
Authors: Jo Yong Hun , Kim Yu Jung , Park Ki Beom , Seong Jeong Hwan , Kim Soo Gon , Park Soyi , Noh Mi Young , Lee Yong Seok , Han Yeon Soo
Published: April 2017

Cactin was originally identified as an interactor of the Drosophila IκB factor Cactus and shown to play a role in controlling embryonic polarity and regulating the NF-κB signaling pathway. While subsequent studies have identified the roles for Cactin in the mammalian immune response, the immune function of Cactin in insects has not been described yet. Here, we identified a Cactin gene from the mealworm beetle, Tenebrio molitor (TmCactin) and characterized its functional role in innate immunity. TmCactin was highly expressed in prepupa to last instar stages, and its expression was high in the integument and Malpighian tubules of last instar larvae and adults. TmCactin was induced in larvae after infection with different pathogens and detectable within 3 hours of infection. The highest levels of TmCactin expression were detected at 9 hours post infection. TmCactin RNAi significantly decreased the survival rates of larvae after challenge with Escherichia coli and Staphylococcus aureus, but had no significant effect after challenge with Candida albicans. Furthermore, TmCactin RNAi significantly reduced the expression of seven antimicrobial peptide genes (AMPs) after bacterial challenge. Our results suggest that TmCactin may serve as an important regulator of innate immunity, mediating AMP responses against both Gram-positive and Gram-negative bacteria in T. molitor.
Host Determinants of Expression of the Helicobacter pylori BabA Adhesin
Authors: Kable Mary E. , Hansen Lori M. , Styer Cathy M. , Deck Samuel L. , Rakhimova Olena , Shevtsova Anna , Eaton Kathryn A. , Martin Miriam E. , Gideonsson Pär , Borén Thomas , Solnick Jay V.
Published: April 2017

Expression of the Helicobacter pylori blood group antigen binding adhesin A (BabA) is more common in strains isolated from patients with peptic ulcer disease or gastric cancer, rather than asymptomatic colonization. Here we used mouse models to examine host determinants that affect H. pylori BabA expression. BabA expression was lost by phase variation as frequently in WT mice as in RAG2−/− mice that do not have functional B or T cells, and in MyD88−/−, TLR2−/− and TLR4−/− mice that are defective in toll like receptor signaling. The presence of other bacteria had no effect on BabA expression as shown by infection of germ free mice. Moreover, loss of BabA expression was not dependent on Leb expression or the capacity of BabA to bind Leb. Surprisingly, gender was the host determinant most associated with loss of BabA expression, which was maintained to a greater extent in male mice and was associated with greater bacterial load. These results suggest the possibility that loss of BabA expression is not driven by adaptive immunity or toll-like receptor signaling, and that BabA may have other, unrecognized functions in addition to serving as an adhesin that binds Leb.
A pathway linking reward circuitry, impulsive sensation-seeking and risky decision-making in young adults: identifying neural markers for new interventions
Authors: Chase H W , Fournier J C , Bertocci M A , Greenberg T , Aslam H , Stiffler R , Lockovich J , Graur S , Bebko G , Forbes E E , Phillips M L
Published: April 2017

High trait impulsive sensation seeking (ISS) is common in 18–25-year olds, and is associated with risky decision-making and deleterious outcomes. We examined relationships among: activity in reward regions previously associated with ISS during an ISS-relevant context, uncertain reward expectancy (RE), using fMRI; ISS impulsivity and sensation-seeking subcomponents; and risky decision-making in 100, transdiagnostically recruited 18–25-year olds. ISS, anhedonia, anxiety, depression and mania were measured using self-report scales; clinician-administered scales also assessed the latter four. A post-scan risky decision-making task measured ‘risky’ (possible win/loss/mixed/neutral) fMRI-task versus ‘sure thing’ stimuli. ‘Bias’ reflected risky over safe choices. Uncertain RE-related activity in left ventrolateral prefrontal cortex and bilateral ventral striatum was positively associated with an ISS composite score, comprising impulsivity and sensation-seeking–fun-seeking subcomponents (ISSc;P⩽0.001). Bias positively associated with sensation seeking–experience seeking (ES;P=0.003). This relationship was moderated by ISSc (P=0.009): it was evident only in high ISSc individuals. Whole-brain analyses showed a positive relationship between: uncertain RE-related left ventrolateral prefrontal cortical activity and ISSc; uncertain RE-related visual attention and motor preparation neural network activity and ES; and uncertain RE-related dorsal anterior cingulate cortical activity and bias, specifically in high ISSc participants (all ps<0.05, peak-level, family-wise error corrected). We identify an indirect pathway linking greater levels of uncertain RE-related activity in reward, visual attention and motor networks with greater risky decision-making, via positive relationships with impulsivity, fun seeking and ES. These objective neural markers of high ISS can guide new treatment developments for young adults with high levels of this debilitating personality trait.
Intranasal oxytocin enhances intrinsic corticostriatal functional connectivity in women
Authors: Bethlehem R A I , Lombardo M V , Lai M-C , Auyeung B , Crockford S K , Deakin J , Soubramanian S , Sule A , Kundu P , Voon V , Baron-Cohen S
Published: April 2017

Oxytocin may influence various human behaviors and the connectivity across subcortical and cortical networks. Previous oxytocin studies are male biased and often constrained by task-based inferences. Here, we investigate the impact of oxytocin on resting-state connectivity between subcortical and cortical networks in women. We collected resting-state functional magnetic resonance imaging (fMRI) data on 26 typically developing women 40 min following intranasal oxytocin administration using a double-blind placebo-controlled crossover design. Independent components analysis (ICA) was applied to examine connectivity between networks. An independent analysis of oxytocin receptor (OXTR) gene expression in human subcortical and cortical areas was carried out to determine plausibility of direct oxytocin effects on OXTR. In women, OXTR was highly expressed in striatal and other subcortical regions, but showed modest expression in cortical areas. Oxytocin increased connectivity between corticostriatal circuitry typically involved in reward, emotion, social communication, language and pain processing. This effect was 1.39 standard deviations above the null effect of no difference between oxytocin and placebo. This oxytocin-related effect on corticostriatal connectivity covaried with autistic traits, such that oxytocin-related increase in connectivity was stronger in individuals with higher autistic traits. In sum, oxytocin strengthened corticostriatal connectivity in women, particularly with cortical networks that are involved in social-communicative, motivational and affective processes. This effect may be important for future work on neurological and psychiatric conditions (for example, autism), particularly through highlighting how oxytocin may operate differently for subsets of individuals.
A new route for the preparation of enriched iso-polylactide from rac-lactide via a Lewis acid catalyzed ring-opening of an epoxide
Authors: Anker Mathew , Balasanthiran Choumini , Balasanthiran Vagulejan , Chisholm Malcolm H. , Jayaraj Savithra , Mathieu Kaleb , Piromjitpong Parichat , Praban Siriwan , Raya Balaram , Simonsick William J.
Published: April 2017

Al(iii) acts as a Lewis acid for the ring-opening of an epoxide by Cl− attack and this yields stereo selective ring-opening polymerization of rac-lactide to yield iso-polylactide.
A novel multi-nitrogen 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane-based energetic co-crystal with 1-methyl-3,4,5-trinitropyrazole as a donor: experimental and theoretical investigations of intermolecular interactions
Authors: Ma Qing , Jiang Tao , Chi Yu , Chen Ya , Wang Jun , Huang Jinglun , Nie Fude
Published: April 2017

A new strategy for the design and preparation of CL-20-based multi-nitrogen energetic co-crystals was revealed by experimental and theoretical approaches.
A tumor-specific and mitochondria-targeted fluorescent probe for real-time sensing of hypochlorite in living cells
Authors: Li Kun , Hou Ji-Ting , Yang Jin , Yu Xiao-Qi
Published: April 2017

The first dual-targeted (both cancer cells and mitochondria) fluorescent probe for sensing mitochondrial hypochlorite was presented and applied in cell imaging.
Direct oxidation of the C(sp2)–C(sp3) bond from benzyltrimethylsilanes to phenols
Authors: Li Wei , Gao Guolin , Gao Yuan , Yang Chao , Xia Wujiong
Published: April 2017

A novel pathway for direct conversion of benzylsilanes to phenols by oxidation with Na2S2O8 and oxygen is efficiently developed under mild and neutral conditions.
(o-Phenyleno)naphthalene diimides: a pink fluorescent chromophore
Authors: Ma Yingjie , Zhang Xiaojie , Stappert Sebastian , Yuan Zhongyi , Li Chen , Müllen Klaus
Published: April 2017

(o-Phenyleno)naphthalene dianhydride 7 was synthesized by a six-step reaction. Imidizations of 7 led to various diimides 8. Their optical and electrochemical properties hold promise for organic electronics.
Temperature dependency of aqueous biphasic systems: an alternative approach for exploring the differences between Coulombic-dominated salts and ionic liquids
Authors: e Silva Francisca A. , Pereira Jorge F. B. , Kurnia Kiki A. , Ventura Sónia P. M. , Silva Artur M. S. , Rogers Robin D. , Coutinho João A. P. , Freire Mara G.
Published: April 2017

An alternative way to distinguish ionic liquids and Coulombic-dominated salts based on the temperature dependency of aqueous biphasic systems.
A beta-Fe2O3 nanoparticle-assembled film for photoelectrochemical water splitting
Authors: Zhang Ningsi , Guo Yongsheng , Wang Xin , Zhang Shiying , Li Zhaosheng , Zou Zhigang
Published: April 2017

Since Fe2O3 is a promising photoanode material for water splitting, it has attracted much attention, while other phases of ferric oxide are ignored. Here, β-Fe2O3 was used as a photoanode material for solar water splitting, and a solar photocurrent of ca. 0.12 mA cm2 at 1.6 VRHE was observed.
Vapor-phase dehydrogenation of ethylbenzene to styrene over a V2O5/TiO2–Al2O3 catalyst with CO2
Authors: Kainthla Itika , Ramesh Babu Gurram Venkata , Bhanushali Jayesh T. , Keri Rangappa S. , Rama Rao Kamaraju Seetha , Nagaraja Bhari Mallanna
Published: April 2017

A stable V2O5/TiO2–Al2O3 catalyst was synthesized for the oxidative dehydrogenation of ethylbenzene to styrene using CO2 as a mild oxidant.
Exploring the reversal of enantioselectivity on a zinc-dependent alcohol dehydrogenase
Authors: Maria-Solano Miguel A. , Romero-Rivera Adrian , Osuna Sílvia
Published: April 2017

Alcohol Dehydrogenase (ADH) enzymes catalyse the reversible reduction of prochiral ketones to the corresponding alcohols.
Lanthanide amide-catalyzed one-pot functionalization of isatins: synthesis of spiro[cyclopropan-1,3′-oxindoles] and 2-oxoindolin-3-yl phosphates
Authors: Peng Cheng , Zhai Jiaojiao , Xue Mingqiang , Xu Fan
Published: April 2017

A lanthanide-catalyzed one-pot reaction using readily accessible substrates was developed affording spiro[cyclopropan-1,3′-oxindoles] in good yields and with high stereoselectivity.
Correction: Nanostructured lipid carrier (NLC)-based novel hydrogels as potential carriers for nepafenac applied after cataract surgery for the treatment of inflammation: design, characterization and in vitro cellular inhibition and uptake studies
Authors: Yu Shihui , Tan Guoxin , Liu Dandan , Yang Xinggang , Pan Weisan
Published: April 2017

Correction for ‘Nanostructured lipid carrier (NLC)-based novel hydrogels as potential carriers for nepafenac applied after cataract surgery for the treatment of inflammation: design, characterization and in vitro cellular inhibition and uptake studies’ by Shihui Yu et al., RSC Adv., 2017, 7, 16668–16677.
Mapping the Early Language Environment Using All-Day Recordings and Automated Analysis
Authors: Gilkerson Jill , Richards Jeffrey A. , Warren Steven F. , Montgomery Judith K. , Greenwood Charles R. , Kimbrough Oller D. , Hansen John H. L. , Paul Terrance D.
Published: April 2017

Purpose

This research provided a first-generation standardization of automated language environment estimates, validated these estimates against standard language assessments, and extended on previous research reporting language behavior differences across socioeconomic groups.

Method

Typically developing children between 2 to 48 months of age completed monthly, daylong recordings in their natural language environments over a span of approximately 6–38 months. The resulting data set contained 3,213 12-hr recordings automatically analyzed by using the Language Environment Analysis (LENA) System to generate estimates of (a) the number of adult words in the child's environment, (b) the amount of caregiver–child interaction, and (c) the frequency of child vocal output.

Results

Child vocalization frequency and turn-taking increased with age, whereas adult word counts were age independent after early infancy. Child vocalization and conversational turn estimates predicted 7%–16% of the variance observed in child language assessment scores. Lower socioeconomic status (SES) children produced fewer vocalizations, engaged in fewer adult–child interactions, and were exposed to fewer daily adult words compared with their higher socioeconomic status peers, but within-group variability was high.

Conclusions

The results offer new insight into the landscape of the early language environment, with clinical implications for identification of children at-risk for impoverished language environments.
Randomized Controlled Trial in Clinical Settings to Evaluate Effectiveness of Coping Skills Education Used With Progressive Tinnitus Management
Authors: Henry James A. , Thielman Emily J. , Zaugg Tara L. , Kaelin Christine , Schmidt Caroline J. , Griest Susan , McMillan Garnett P. , Myers Paula , Rivera Izel , Baldwin Robert , Carlson Kathleen
Published: April 2017

Purpose

This randomized controlled trial evaluated, within clinical settings, the effectiveness of coping skills education that is provided with progressive tinnitus management (PTM).

Method

At 2 Veterans Affairs medical centers,N= 300 veterans were randomized to either PTM intervention or 6-month wait-list control. The PTM intervention involved 5 group workshops: 2 led by an audiologist (teaching how to use sound as therapy) and 3 by a psychologist (teaching coping skills derived from cognitive behavioral therapy). It was hypothesized that PTM would be more effective than wait-list control in reducing functional effects of tinnitus and that there would be no differences in effectiveness between sites.

Results

At both sites, a statistically significant improvement in mean Tinnitus Functional Index scores was seen at 6 months for the PTM group. Combined data across sites revealed a statistically significant improvement in Tinnitus Functional Index relative to wait-list control. The effect size for PTM using the Tinnitus Functional Index was 0.36 (small).

Conclusions

Results suggest that PTM is effective at reducing tinnitus-related functional distress in clinical settings. Although effect sizes were small, they provide evidence of clinical effectiveness of PTM in the absence of stringent research-related inclusion criteria and with a relatively small number of sessions of cognitive behavioral therapy.
University Students' Perceptions of a Person Who Clutters With or Without Video Education
Authors: Blanchet Paul G. , Farrell Lindsey M. , Snyder Greg
Published: April 2017

Purpose

The purpose of this study was to examine the effects of video education about cluttering on students' perceptions of a person who clutters.

Method

A total of 193 undergraduate students served as participants. Ninety-five students were provided with a written definition of cluttering, while 98 were also provided with video education about cluttering. Students then rated a person who clutters on speech and personality scales.

Results

Results yielded significant group differences in ratings of intelligibility, speech rate, ease of listening, and competence. Respondents who viewed the educational video rated a person who clutters significantly more negatively along these dimensions than respondents who read a definition only. However, participants who did not view the video reported knowing significantly more people who clutter.

Conclusion

Findings suggest that this particular form of video education might provide students with “realistic” exposure to cluttering. Further research is needed to assess effects of exposure to and interaction with a person who clutters on perceptions of cluttering. Implications include the impact of prior exposure to those who clutter, as well as potential confusion between cluttering and “fast speech.” These factors might have influenced identification rates of individuals who clutter, which could have affected the results.
Intercepting the Nazarov Oxyallyl Intermediate with α-Formyl­vinyl Anion Equivalents to Access Formal Morita–Baylis–Hillman Alkylation Products
Authors: West F. , Wu Yen-Ku , Lin Rongrong
Published: April 2017

A Lewis acid catalyzed cationic domino reaction involving sequential electrocyclization and polar addition of allenol ethers onto the resulting oxyallyl species is described. The overall sequence allows a highly stereoselective synthesis of densely substituted cyclopentanoid compounds containing α-formylvinyl functionality which is formally equivalent to products of a Morita–Baylis–Hillman alkylation process.
A Short Asymmetric Synthesis of Sauropunols A–D
Authors: Gracza Tibor , Markovič Martin , Koóš Peter
Published: April 2017

A short and efficient asymmetric synthesis of natural sauropunols A, B, and C/D has been accomplished in 6 steps from divinylcarbinol with overall yield of 19%, 7% and 32%, respectively. The key synthetic steps include effective Sharpless asymmetric epoxidation of penta-1,4-dien-3-ol and a highly diastereoselective Pd-catalysed oxycarbonylation of pentene-1,2,3-triol. The structures of sauropunols A and B have been confirmed.
Laser-driven fast electron ionization wave propagation in a dielectric target
Authors: Bai Yafeng , Tian Ye , Zhou Shiyi , Zeng Yushan , Sun Haiyi , Wang Cheng , Liu Jiansheng
Published: April 2017

Ultrafast shadowgraphy with sub-picosecond resolution is applied to investigate the propagation of laser-driven fast electron beams inside a dielectric target. Time-resolved expansion of an ionization sphere caused by hot electron transportation in the target is observed. An abnormal absorption area with a width of approximately 10 μm is observed near the ionization front and is consistent with the one-dimensional electron transport model. The observed distortions of the edge diffraction fringes near the surface of the target are analyzed to qualitatively retrieve the phase shift caused by the ionization front. A simplified three-dimensional model is proposed to analyze the underlying physics and indicates that the valley in the ionization front appears due to the unstable propagation of hot electrons in a self-induced fountain electric field, which is induced by the collective effect of the free electrons and the ions.
Crystal structures of model lithium halides in bulk phase and in clusters
Authors: Lanaro G. , Patey G. N.
Published: April 2017

We employ lattice energy calculations and molecular dynamics simulations to compare the stability of wurtzite and rock salt crystal structures of four lithium halides (LiF, LiCl, LiBr, and LiI) modeled using the Tosi-Fumi and Joung-Cheatham potentials, which are models frequently used in simulation studies. Both infinite crystals and finite clusters are considered. For the Tosi-Fumi model, we find that all four salts prefer the wurtzite structure both at 0 K and at finite temperatures, in disagreement with experiments, where rock salt is the stable structure and wurtzite exists as a metastable state. For Joung-Cheatham potentials, rock salt is more stable for LiF and LiCl, but the wurtzite structure is preferred by LiBr and LiI. It is clear that the available lithium halide force fields need improvement to bring them into better accord with the experiment. Finite-size clusters that are more stable as rock salt in the bulk phase tend to solidify as small rock salt crystals. However, small clusters of salts that prefer the wurtzite structure as bulk crystals tend to form structures that have hexagonal motifs, but are not finite-size wurtzite crystals. We show that small wurtzite structures are unstable due to the presence of a dipole and rearrange into more stable, size-dependent structures. We also show that entropic contributions can act in favor of the wurtzite structure at higher temperatures. The possible relevance of our results for simulation studies of crystal nucleation from melts and/or aqueous solutions is discussed.
Influence of sample pool on interference pattern in defocused interferometric particle imaging
Authors: Zhang Hongxia , Zhou Ye , Liu Jing , Jia Dagong , Liu Tiegen
Published: April 2017

Particles widely exist in various fields. In practical experiments, sometimes it is necessary to dissolve particles in water in a sample pool. This article proposes two typical layouts of the sample pool in defocused interferometric particle imaging (IPI). Layout I is the sample pool surface perpendicular to the incident light and layout II is the sample pool surface perpendicular to the scattered light. For layout I, the scattered light of the particles does not keep symmetric at the meridional and sagittal planes after being refracted by the sample pool surface, and elliptical interference patterns are formed at the defocused IPI image plane. But for layout II, the scattered light keeps symmetric after being refracted, and circular interference patterns are formed. Aimed at the two sample pool layouts, the ray-tracing software ZEMAX was used to simulate the spot shape of particles at different defocus distances. Furthermore, its effect on the ellipticity of the interference pattern with the tilt angle of the sample pool is analyzed. The relative error of the axis ratio for layout I does not exceed 9.2% at different defocus distances. The experimental results have good agreement with the theoretical analyses, and it indicates that layout II is more reasonable for the IPI system.
Mechanism for bipolar resistive switching memory behaviors of a self-assembled three-dimensional MoS2 microsphere composed active layer
Authors: Zhou G. D. , Lu Z. S. , Yao Y. Q. , Wang G. , Yang X. D. , Zhou A. K. , Li P. , Ding B. F. , Song Q. L.
Published: April 2017

A self-assembled three-dimensional (3-D) MoS2 microsphere-based memristor with a favorable ON/OFF resistance ratio of ∼104, endurance, and retention time is demonstrated at room temperature. The formation and rupture of a localized Ag metallic filament, establishment and destruction of a boundary-based hopping path, and charge trapping and detrapping from the space charge region co-contribute to the bipolar resistive switching memory behaviours observed in the device of Ag/MoS2/ITO. This work may give insight into the mechanism of the resistive switching memory behaviours of a device with a 3-D micro-scale.
Filamentary electrical conduction in polyimide films detected by infrared thermography before thermal breakdown
Authors: Diaham S. , Belijar G. , Locatelli M.-L. , Lebey T.
Published: April 2017

An experimental evidence of filamentary electrical conduction existence in polyimide (PI) films under DC voltage just prior to thermal breakdown is reported. This was achieved by real-time surface temperature mapping of PI-metallized samples initially at 300 °C using fast infrared thermography coupled to current-voltage measurements until the breakdown. The transition from a full-electrode conduction to a filamentary conduction is clearly identified through the detection of a localized hot spot within the PI samples in the last 100–150 ms before breakdown. A conduction path, with values inferior to 500 μm in the few ms before the breakdown, was estimated leading to temperature rising up to 100 K above the initial temperature. This work confirms the existence of a filamentary conduction in thermoset polymers prior thermal breakdown.
Piezo-Hall effect and fundamental piezo-Hall coefficients of single crystal n-type 3C-SiC(100) with low carrier concentration
Authors: Qamar Afzaal , Dao Dzung Viet , Dinh Toan , Iacopi Alan , Walker Glenn , Phan Hoang-Phuong , Hold Leonie , Dimitrijev Sima
Published: April 2017

This article reports the results on the piezo-Hall effect in single crystal n-type 3C-SiC(100) having a low carrier concentration. The effect of the crystallographic orientation on the piezo-Hall effect has been investigated by applying stress to the Hall devices fabricated in different crystallographic directions. Single crystal n-type 3C-SiC(100) and 3C-SiC(111) were grown by low pressure chemical vapor deposition at 1250 °C. Fundamental piezo-Hall coefficients were obtained using the piezo-Hall effect measurements as P11 = (–29 ± 1.3) × 10−11 Pa−1, P12 = (11.06 ± 0.5)× 10−11 Pa−1, and P44 = (–3.4 ± 0.7) × 10−11 Pa−1. It has been observed that the piezo-Hall coefficients of n-type 3C-SiC(100) show a completely different behavior as compared to that of p-type 3C-SiC.
Layer thickness dependent strain rate sensitivity of Cu/amorphous CuNb multilayer
Authors: Fan Z. , Liu Y. , Xue S. , Rahimi R. M. , Bahr D. F. , Wang H. , Zhang X.
Published: April 2017

Strain rate sensitivity of crystalline materials is closely related to dislocation activity. In the absence of dislocations, amorphous alloys are usually considered to be strain rate insensitive. However, the strain rate sensitivity of crystalline/amorphous composites is rarely studied, especially at nanoscale. In this study, we show that the strain rate sensitivity of Cu/amorphous CuNb multilayers is layer thickness dependent. At small layer thickness (below 50 nm), the multilayers demonstrate limited strain rate sensitivity; at relatively large layer thickness (above 100 nm), the strain rate sensitivity of multilayers is close to that of the single layer Cu film. Mechanisms that lead to size dependent variation of strain rate sensitivity in these multilayers are discussed.
Space dependent, full orbit effects on runaway electron dynamics in tokamak plasmas
Authors: Carbajal L. , del-Castillo-Negrete D. , Spong D. , Seal S. , Baylor L.
Published: April 2017

The dynamics of RE (runaway electrons) in fusion plasmas span a wide range of temporal scales, from the fast gyro-motion, ∼10−11 s, to the observational time scales, ∼10−2→1 s. To cope with this scale separation, RE are usually studied within the bounce-average or the guiding center approximations. Although these approximations have yielded valuable insights, a study with predictive capabilities of RE in fusion plasmas calls for the incorporation of full orbit effects in configuration space in the presence of three-dimensional magnetic fields. We present numerical results on this problem using the Kinetic Orbit Runaway electrons Code that follows relativistic electrons in general electric and magnetic fields under the full Lorentz force, collisions, and radiation losses. At relativistic energies, the main energy loss is due to radiation damping, which we incorporate using the Landau-Lifshitz formulation of the Abraham-Lorentz-Dirac force. The main focus is on full orbit effects on synchrotron radiation. It is shown that even in the absence of magnetic field stochasticty, neglecting orbit dynamics can introduce significant errors in the computation of the total radiated power and the synchrotron spectra. The statistics of collisionless (i.e., full orbit induced) pitch angle dispersion, and its key role played on synchrotron radiation, are studied in detail. Numerical results are also presented on the pitch angle dependence of the spatial confinement of RE and on full orbit effects on the competition of electric field acceleration and radiation damping. Finally, full orbit calculations are used to explore the limitations of gyro-averaging in the relativistic regime. To explore the practical impact of the results, DIII-D and ITER-like parameters are used in the simulations.
The temporal evolution of the drift-cyclotron instability and anomalous ion heating in plasmas with transverse inhomogeneous electric field
Authors: Mikhailenko V. S. , Mikhailenko V. V. , June Lee Hae
Published: April 2017

The effect of the sheared flow across the magnetic field on drift-cyclotron turbulence is investigated with applications to anomalous ion heating in space plasmas employing the non-modal methodology of sheared modes. These modes are the waves that have a static spatial structure in the frame of the background flow and are the sheared modes in the laboratory frame. The analysis consists in the solution of the governing integral equation for the electrostatic potential in the time domain. It reveals that the instability experiences the non-modal temporal evolution in the sheared flow during which the unstable perturbation becomes very different from a canonical modal form. It displays that the growth rate of the drift-cyclotron instability and the turbulent ion heating rate decrease with time due to the shearing of ion cyclotron waves by the sheared flow. The effect of the quenching time of the drift-cyclotron instability and of the ion heating is confirmed also by the solution of the nonlinear integral equation, which accounts for the random scattering of the angle of ion gyro-motion due to the interaction of ions with an ensemble of sheared waves.
The properties of two-dimensional fractal plasma photonic crystals with Thue-Morse sequence
Authors: Zhang Hai-Feng , Chen Yu-Qing
Published: April 2017

In this paper, the properties of the acceptor modes and photonic band gaps (PBGs) of two-dimensional (2D) fractal plasma photonic crystals (PPCs) under a transverse-magnetic wave are theoretically studied by a modified plane wave expansion method. The density of states is calculated to elaborate the characteristics of the proposed 2D PPCs in which the dielectric cylinders are inserted in the plasma background according to the iteration rule of the Thue-Morse sequence with square lattices. The band structures of the proposed PPCs and 2D PPCs with a conventional square lattice are numerically determined to analyse the properties of PBGs and acceptor modes. The results illustrate that the performance is improved in the proposed PPCs compared to the 2D conventional PPCs with similar lattices. The larger PBGs and higher cutoff frequency are obtained when the Thue-Morse structure is introduced. The lowest edges of PBGs are flat, and they are originated from the Mie resonances. The acceptor modes can be considered as the quasi-localized states since the Thue-Morse sequence has the self-similarity and non-periodicity at the same time. The influences of configurational parameters on the properties of the proposed PPCs are studied in detail as well. The results demonstrate that the PBGs and acceptor modes can be easily tuned by changing those configurational parameters.
Nonlinear optical properties and application of a chiral and photostimulable iron(II) compound
Authors: Iazzolino A. , Ould Hamouda A. , Naïm A. , Stefánczyk O. , Rosa P. , Freysz E.
Published: April 2017

We measure linear absorption, circular dichroism, second harmonic, and sum frequency generation in the [Δ-Fe(phen)3](Δ-As2(tartarate)2), [Λ-Fe(phen)3](Λ-As2(tartarate)2) enantiomers of an Fe(II) complex. In the solid state, the chirality of this compound results from the introduction of the (As2(tartarate)2) chiral anions. Linear absorption and X-ray diffraction indicate that Fe(II) is in the low-spin state. Circular dichroïsm reveals that in the solid state, these compounds are chiral, whereas the complexes racemize in solution. A large second harmonic generation signal is recorded using thin films from these two enantiomers. The second-order susceptibility χ111(2) of these compounds is evaluated across the visible spectral range. It displays a resonance at 520 nm, which is associated with the metal-to-ligand charge transfer occurring within the complex. At its maximum, χ111(2) = 6.4 pm V−1 is more than 1.4 times larger than the well-known beta-BaB2O4 nonlinear crystal (χ122(2) ∼ 4.4 pm V−1). Finally, we demonstrate a useful application for a thin film from this compound, which characterizes the cross-correlation of two femtosecond laser pulses.
Enhancement of responsivity for a transistor terahertz detector by a Fabry-Pérot resonance-cavity
Authors: Hou H. W. , Liu Z. , Teng J. H. , Palacios T. , Chua S. J.
Published: April 2017

A method to enhance the responsivity of a transistor terahertz (THz) detector by introducing a Fabry-Pérot (FP) cavity was proposed. A theoretical model for the voltage responsivity of the transistor THz detector with a resonant cavity was derived and verified experimentally using a GaN high electron mobility transistor (HEMT) with the FP cavity formed between the GaN HEMT substrate and an indium tin oxide mirror. The measured detector responsivity shows 2.5 times enhancement compared to the device without the cavity and lower noise equivalent power. The performance of the GaN HEMT THz detector with a FP cavity, which has a designed quality factor of 16, is dependent on the incident angle of the THz radiation.
Self-diffusion in liquid Al-Ge investigated with quasi-elastic neutron scattering
Authors: Szabó Sandro , Evenson Zach
Published: April 2017

Quasi-elastic neutron scattering measurements are carried out to investigate the self-diffusion of Ge in liquid Al-Ge alloys in a wide temperature range at and below the melting point of the respective pure elements. In all investigated Al-Ge alloys, the self-diffusivity of Ge follows an Arrhenius behavior over the entire investigated temperature range and shows a standard deviation of only 4%, which is significantly more precise when compared to classical measurements in long capillaries. At the melting point of pure Ge, the self-diffusivity of Ge in all investigated alloys is higher by some 22%–28% than that of pure Ge and shows a diffusion maximum at 41 at. % Ge. This can be understood as an increase in chemical interactions between Al and Ge in this composition region and is in line with previous experimental findings regarding fast dendrite growth during solidification.
Effect of stress on melting of rhombohedral bismuth
Authors: Lin Chuanlong , Smith Jesse S. , Sinogeikin Stanislav V. , Shen Guoyin
Published: April 2017

Pressure-induced melting of rhombohedral bismuth (Bi-I) has been investigated in the solid pressure medium of NaCl and the hydrostatic medium of neon at high temperatures by in-situ synchrotron x-ray diffraction. Upon compression from ∼0.7 GPa to 3.2 GPa at (or below) 489 K, Bi-I melts into a liquid between ∼1.2 and 1.6 GPa in the solid pressure medium and then crystallizes into Bi-IV at ∼2.9 GPa. However, at the same temperature of 489 K, Bi-I transforms to a crystalline phase (Bi-II′ or Bi-II) at ∼1.8 GPa under hydrostatic conditions, followed by a transformation to Bi-IV at 2.5 GPa. Our x-ray diffraction results indicate that the melting of Bi-I at (or below) 489 K is due to the stress. There is a stress effect on the structural deformation of Bi-I when the solid pressure medium is used, viz., pressure-dependent c/a for Bi-I in the solid pressure medium is larger or smaller than that under hydrostatic conditions. According to the classical nucleation theory, the stress provides an additional driving force, leading to the reduction of the free energy barrier in the formation of liquid nuclei and thus melting temperature. Additionally, the melting of Bi-I may also be favored by heterogeneous nucleation of the liquid on the boundary between the solid medium and the Bi sample, further contributing to the reduction of the melting temperature.
Proteomic analysis of the endometrium during early pregnancy in the domestic pig
Authors: Kolakowska Justyna , Souchelnytskyi Serhiy , Saini Ravi Kanth Rao , Franczak Anita
Published: April 2017

Reproductive processes in domestic pigs have been studied extensively. Pigs are one of the main sources of meat for human consumption and are an established model for investigations into mammalian, including human, reproductive physiology. Studies of the uterus during early pregnancy will lead to a better understanding of mechanisms governing pregnancy. Proteomics provides the possibility to explore endometrial functions in an unbiased way. The aim of the study was to compare endometrium harvested from Days 12–13 and 15–16 of pregnancy with the corresponding days of the oestrous cycle. We identified endometrial proteins that are unique to the early stages of pregnancy (Days 12–13 and 15–16). Twenty-one proteins were identified that were uniquely expressed on the selected days of pregnancy or the oestrous cycle. Out of 21 identified proteins, 14 referred to the pregnancy periods. Systemic analysis of the identified proteins revealed cell adhesion and cytoskeletal organisation as two of the major functions, both of which are important for the establishment and maintenance of pregnancy. Thrombospondin 1 expression was validated using western blotting analysis and the results suggest its involvement in the adhesiveness of the embryo during the peri-implantation period in pigs.
Habitat characteristics of a threatened arboreal marsupial and its resource use in a degraded landscape: the brush-tailed phascogale (Phascogale tapoatafa tapoatafa) in central Victoria, Australia
Authors: Mansfield C. , Arnold A. H. , Bell T. L. , York A.
Published: April 2017

Context Habitat loss and degradation has contributed significantly to the decline of many species worldwide. To address this loss, we first require a comprehensive understanding of habitat requirements and resource-use patterns of the species under threat. Aims The study aimed to quantify variation in the habitat of a species threatened by habitat loss and degradation, the brush-tailed phascogale (Phascogale tapoatafa tapoatafa), by measuring several physical characteristics of trees and ground cover, as well as to determine potential foraging resource preferences using abundance data from a long-term monitoring study. Methods Phascogale monitoring surveys were conducted over a 13-year period from 2000 to 2012. Habitat variables characterising tree communities, ground cover and coarse woody debris were used to develop explanatory models of phascogale abundance at the site scale. Tree species preference by foraging phascogales was evaluated by comparing usage (trees on which they were captured) and availability. Key results The highest overall animal abundance was at sites characterised by associations of red stringybark, red box, grey box and broad-leaved and narrow-leaved peppermints. At these sites, red stringybark and grey box trees were of small diameter and tended to have small hollows. These sites also had low average tree height, low grass and/or herb and shrub cover and low volumes of coarse woody debris. From a resource-use perspective, phascogales foraged preferentially on certain species of Eucalyptus. Conclusions Our study suggests that phascogale abundance is highly spatially and temporally variable, most likely as a response to heterogeneity in habitat and foraging resources operating at a range of spatial scales. Implications This study has provided new information concerning spatial patterns of phascogale abundance and resource use within a forested area in central Victoria that has been subjected to multiple disturbances. Currently, the composition and age structure of tree communities and ground habitats are a response to severe disturbance due to past mining and harvesting activities. Successful conservation of this threatened species could be enhanced through active management of this forest to maintain the ongoing supply of nesting hollows and foraging resources.
Drebrin restricts rotavirus entry by inhibiting dynamin-mediated endocytosis
Authors: Li Bin , Ding Siyuan , Feng Ningguo , Mooney Nancie , Ooi Yaw Shin , Ren Lili , Diep Jonathan , Kelly Marcus R. , Yasukawa Linda L. , Patton John T. , Yamazaki Hiroyuki , Shirao Tomoaki , Jackson Peter K. , Greenberg Harry B.
Published: April 2017

Significance

Many clinically significant human viral and bacterial pathogens use dynamin-dependent endocytosis to initiate infection or deliver toxin into host cells. Owing to the complex nature of this cellular process, the molecular mechanisms that regulate this pathway remain to be fully elucidated. Here, we use rotavirus (RV) as a model and identify drebrin as a regulatory protein that restricts the cell entry of multiple viruses. We demonstrate that genetic depletion or chemical inhibition of drebrin leads to enhanced RV infection in vitro and increased diarrhea incidence and virus shedding in vivo. Our current study provides insights into endocytosis regulation in general and highlights the potential broad application of blocking drebrin to augment the uptake of viruses and other dynamin-mediated cargo.
Using microsecond single-molecule FRET to determine the assembly pathways of T4 ssDNA binding protein onto model DNA replication forks
Authors: Phelps Carey , Israels Brett , Jose Davis , Marsh Morgan C. , von Hippel Peter H. , Marcus Andrew H.
Published: April 2017

Significance

A microsecond-resolved single-molecule FRET method was used to monitor the binding and unbinding of the ssDNA binding protein (gene product 32) of the T4 bacteriophage replication complex to biologically relevant primer-template DNA constructs. A unique multitime correlation function analysis was applied to the resulting sparse data, which permitted the investigation of the kinetics and mechanisms of noncooperative and cooperative protein binding, unbinding, and “sliding.” Our results indicate that noncooperatively bound monomer proteins dissociate on the timescale of tens of milliseconds, which is consistent with the known rate of nucleotide addition during DNA replication. The rapid dissociation of the monomer suggests that sliding is a much more likely mechanism for translocation of cooperatively bound clusters of indeterminate size.
Structure and mechanics of aegagropilae fiber network
Authors: Verhille Gautier , Moulinet Sébastien , Vandenberghe Nicolas , Adda-Bedia Mokhtar , Le Gal Patrice
Published: April 2017

Significance

Aegagropilae are centimeter-sized, nearly spherical fiber aggregate found on Mediterranean beaches. They result from aggregation and compaction of the remains of the seagrass
Posidonia oceanica
. We find that they possess remarkable mechanical properties, which are unexpected for a structure formed by random agitation caused by sea motion and held together solely by friction between the fibers. The study of such material offers perspectives for complex materials, such as felts and insulation materials.
Redefining the essential trafficking pathway for outer membrane lipoproteins
Authors: Grabowicz Marcin , Silhavy Thomas J.
Published: April 2017

Significance

In Gram-negative bacteria, most lipoproteins synthesized in the inner membrane (IM) are trafficked to the outer membrane (OM). The Lol pathway is the trafficking paradigm: LolCDE releases lipoproteins from the IM; LolA shuttles them between membranes to LolB in the OM. Several OM lipoproteins are essential for viability. In apparent concordance, the Lol proteins are each essential in wild-type cells. However, we show that
Escherichia coli
grows well without LolA and LolB in the absence of one nonessential substrate and appropriately engineered stress responses, revealing that LolAB do not perform truly essential mechanistic roles in trafficking. Rather, LolAB are needed to prevent toxic lipoprotein mislocalization. Our findings change the prevailing paradigm and reveal the existence of an alternate trafficking route.
Small molecule-mediated inhibition of myofibroblast transdifferentiation for the treatment of fibrosis
Authors: Bollong Michael J. , Yang Baiyuan , Vergani Naja , Beyer Brittney A. , Chin Emily N. , Zambaldo Claudio , Wang Danling , Chatterjee Arnab K. , Lairson Luke L. , Schultz Peter G.
Published: April 2017

Significance

The treatment of fibrosis remains a critically important unmet medical need, as nearly 45% of all natural deaths in the Western world are attributed to chronic fibroproliferative disease complications. Fibrosis is characterized by the excessive deposition of extracellular matrix proteins by resident fibroblast-derived myofibroblasts. From an imaging-based screen, we identified the antifungal drug itraconazole as an inhibitor of myofibroblast transdifferentiation from multiple resident fibroblast populations. A derivative of this drug was found to inhibit fibrotic disease progression in mouse models of lung, liver, and skin fibrosis, demonstrating that inhibiting differentiation to the myofibroblast cell state is a practical strategy to treat a wide range of fibrosis-related diseases.
Influence of smoking on contralateral suppression of distortion product otoacoustic emissions
Authors: Prabhu Prashanth , Kumar Prajwal , Goyal Swati , Varma Gowtham , Dutta Kristi Kaveri
Published: April 2017

The present study attempted to determine the influence of smoking on contralateral suppression of distortion product otoacoustic emissions (DPOAE). It was attempted to determine the differences in the amount of contralateral suppression of DPOAE between smokers and non-smokers. In addition, correlation was also determined among duration of smoking, frequency of smoking and number of cigarettes per day on contralateral suppression of DPOAE. The study was carried out on 25 smokers and non-smokers. The results of the study showed that the amount of suppression was reduced in smokers at all the frequencies suggesting an efferent auditory system dysfunction. The increase in the duration of smoking, the frequency of smoking and the number of cigarattes smoked correlated negatively with the amount of suppression. This shows that chronic smoking habits increases the risk of efferent auditory damage. Thus, the present study highlights the ill-effects of smoking on efferent auditory system.