bluuebunny/crossref_metadata_2025 huggingface dataset:
Annexin A1 Deficiency does not Affect Myofiber Repair but Delays Regeneration of Injured Muscles
Authors: Leikina Evgenia , Defour Aurelia , Melikov Kamran , Van der Meulen Jack H. , Nagaraju Kanneboyina , Bhuvanendran Shivaprasad , Gebert Claudia , Pfeifer Karl , Chernomordik Leonid V. , Jaiswal Jyoti K.
Published: December 2015

Repair and regeneration of the injured skeletal myofiber involves fusion of intracellular vesicles with sarcolemma and fusion of the muscle progenitor cells respectively. In vitro experiments have identified involvement of Annexin A1 (Anx A1) in both these fusion processes. To determine if Anx A1 contributes to these processes during muscle repair in vivo, we have assessed muscle growth and repair in Anx A1-deficient mouse (AnxA1−/−). We found that the lack of Anx A1 does not affect the muscle size and repair of myofibers following focal sarcolemmal injury and lengthening contraction injury. However, the lack of Anx A1 delayed muscle regeneration after notexin-induced injury. This delay in muscle regeneration was not caused by a slowdown in proliferation and differentiation of satellite cells. Instead, lack of Anx A1 lowered the proportion of differentiating myoblasts that managed to fuse with the injured myofibers by days 5 and 7 after notexin injury as compared to the wild type (w.t.) mice. Despite this early slowdown in fusion of Anx A1−/− myoblasts, regeneration caught up at later times post injury. These results establish in vivo role of Anx A1 in cell fusion required for myofiber regeneration and not in intracellular vesicle fusion needed for repair of myofiber sarcolemma.
Population genetic analysis reveals cryptic sex in the phytopathogenic fungus Alternaria alternata
Authors: Meng Jing-Wen , Zhu Wen , He Meng-Han , Wu E-Jiao , Duan Guo-Hua , Xie Ye-Kun , Jin Yu-Jia , Yang Li-Na , Shang Li-Ping , Zhan Jiasui
Published: December 2015

Reproductive mode can impact population genetic dynamics and evolutionary landscape of plant pathogens as well as on disease epidemiology and management. In this study, we monitored the spatial dynamics and mating type idiomorphs in ~700 Alternaria alternata isolates sampled from the main potato production areas in China to infer the mating system of potato early blight. Consistent with the expectation of asexual species, identical genotypes were recovered from different locations separated by hundreds of kilometers of geographic distance and spanned across many years. However, high genotype diversity, equal MAT1-1 and MAT1-2 frequencies within and among populations, no genetic differentiation and phylogenetic association between two mating types, combined with random association amongst neutral markers in some field populations, suggested that sexual reproduction may also play an important role in the epidemics and evolution of the pathogen in at least half of the populations assayed despite the fact that no teleomorphs have been observed yet naturally or artificially. Our results indicated that A. alternata may adopt an epidemic mode of reproduction by combining many cycles of asexual propagation with fewer cycles of sexual reproduction, facilitating its adaptation to changing environments and making the disease management on potato fields even more difficult.
Brain plasticity and cognitive functions after ethanol consumption in C57BL/6J mice
Authors: Stragier E , Martin V , Davenas E , Poilbout C , Mongeau R , Corradetti R , Lanfumey L
Published: December 2015

Acute or chronic administrations of high doses of ethanol in mice are known to produce severe cognitive deficits linked to hippocampal damage. However, we recently reported that chronic and moderate ethanol intake in C57BL/6J mice induced chromatin remodeling within the Bdnf promoters, leading to both enhanced brain-derived neurotrophic factor (BDNF) expression and hippocampal neurogenesis under free-choice protocol. We performed here a series of cellular and behavioral studies to analyze the consequences of these modifications. We showed that a 3-week chronic free-choice ethanol consumption in C57BL/6J mice led to a decrease in DNA methylation of the Bdnf gene within the CA1 and CA3 subfields of the hippocampus, and upregulated hippocampal BDNF signaling pathways mediated by ERK, AKT and CREB. However, this activation did not affect long-term potentiation in the CA1. Conversely, ethanol intake impaired learning and memory capacities analyzed in the contextual fear conditioning test and the novel object recognition task. In addition, ethanol increased behavioral perseveration in the Barnes maze test but did not alter the mouse overall spatial capacities. These data suggested that in conditions of chronic and moderate ethanol intake, the chromatin remodeling leading to BDNF signaling upregulation is probably an adaptive process, engaged via epigenetic regulations, to counteract the cognitive deficits induced by ethanol.
Nucleus accumbens deep brain stimulation in a rat model of binge eating
Authors: Doucette W T , Khokhar J Y , Green A I
Published: December 2015

Binge eating (BE) is a difficult-to-treat behavior with high relapse rates, thus complicating several disorders including obesity. In this study, we tested the effects of high-frequency deep brain stimulation (DBS) in a rodent model of BE. We hypothesized that BE rats receiving high-frequency DBS in the nucleus accumbens (NAc) core would have reduced binge sizes compared with sham stimulation in both a ‘chronic BE’ model as well as in a ‘relapse to chronic BE’ model. Male Sprague–Dawley rats (N=18) were implanted with stimulating electrodes in bilateral NAc core, and they received either active stimulation (N=12) or sham stimulation (N=6) for the initial chronic BE experiments. After testing in the chronic BE state, rats did not engage in binge sessions for 1 month, and then resumed binge sessions (relapse to chronic BE) with active or sham stimulation (N=5–7 per group). A significant effect of intervention group was observed on binge size in the chronic BE state, but no significant difference between intervention groups was observed in the relapse to chronic BE experiments. This research, making use of both a chronic BE model as well as a relapse to chronic BE model, provides data supporting the hypothesis that DBS of the NAc core can decrease BE. Further research will be needed to learn how to increase the effect size and decrease deep brain stimulation-treatment outcome variability across the continuum of BE behavior.
Identification of the chemical compositions of Ponkan peel by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry
Authors: Yang Ying , Zhao Xi Juan , Pan Yu , Zhou Zhiqin
Published: December 2015

A new UPLC-Q-TOF-MS method has been reported for the qualitative analysis and profiling of chemical compositions of Ponkan peel.
Tri-membrane nanoparticles produced by combining liposome fusion and a novel patchwork of bicelles to overcome endosomal and nuclear membrane barriers to cargo delivery
Authors: Yamada Asako , Mitsueda Asako , Hasan Mahadi , Ueda Miho , Hama Susumu , Warashina Shota , Nakamura Takashi , Harashima Hideyoshi , Kogure Kentaro
Published: December 2015

Tri-membrane PD-MEND deliver cargo by sophisticated membrane fusions.
Single point mutation detection in living cancer cells by far-red emitting PNA–FIT probes
Authors: Kolevzon N. , Hashoul D. , Naik S. , Rubinstein A. , Yavin E.
Published: December 2015

SNP detection of the mutated kRAS oncogene in living cells is shown to be achieved for the first time by cell-permeable and far-red emitting PNA–FIT probes.
Circular dichroism based refractive index sensing using chiral metamaterials
Authors: He Yizhuo , Lawrence Keelan , Ingram Whitney , Zhao Yiping
Published: December 2015

A new strategy to improve the sensitivity of localized surface plasmon resonance sensors by employing chiral metamaterials is provided.
Low temperature selective oxidation of methane to methanol using titania supported gold palladium copper catalysts
Authors: Ab Rahim Mohd Hasbi , Armstrong Robert D. , Hammond Ceri , Dimitratos Nikolaos , Freakley Simon J. , Forde Michael M. , Morgan David J. , Lalev Georgi , Jenkins Robert L. , Lopez-Sanchez Jose Antonio , Taylor Stuart H. , Hutchings Graham J.
Published: December 2015

Selective oxidation of methane using AuPdCu/TiO2 catalysts.
Long persistent luminescence in the ultraviolet in Pb2+-doped Sr2MgGe2O7persistent phosphor
Authors: Liang Yanjie , Liu Feng , Chen Yafei , Sun Kangning , Pan Zhengwei
Published: December 2015

Persistent luminescence in the ultraviolet region is achieved in Sr2MgGe2O7:Pb phosphor with a long persistence time of more than 12 h.
One pot synthesis of substituted imidazopyridines and thiazoles from styrenes in water assisted by NBS
Authors: Shinde Mahesh H. , Kshirsagar Umesh A.
Published: December 2015

Heating of commercially available styrenes with NBS in water followed by reaction with 2-aminopyridines and thioamides afforded important heterocyclic scaffolds in a one pot procedure.
A photoactive bimetallic framework for direct aminoformylation of nitroarenes
Authors: Nasir Baig R. B. , Verma Sanny , Nadagouda Mallikarjuna N. , Varma Rajender S.
Published: December 2015

A bimetallic catalyst, AgPd@g-C3N4, on graphitic carbon nitride enables the concerted reductive formylation of aromatic nitro compounds under photo-chemical conditions; formic acid serves the dual role of a hydrogen source and a formylating agent.
Internal standardization of LA-ICP-MS immuno imaging via printing of universal metal spiked inks onto tissue sections
Authors: Hoesl Simone , Neumann Boris , Techritz Sandra , Sauter Guido , Simon Ronald , Schlüter Hartmut , W. Linscheid Michael , Theuring Franz , Jakubowski Norbert , Mueller Larissa
Published: December 2015

This paper presents the application of printed metal spiked inks for standardization of tissue sections analyzed by LA-ICP-MS imaging.
On-chip preparation of nanoscale contrast agents towards high-resolution ultrasound imaging
Authors: Peyman Sally A. , McLaughlan James R. , Abou-Saleh Radwa H. , Marston Gemma , Johnson Benjamin R. G. , Freear Steven , Coletta P. Louise , Markham Alexander F. , Evans Stephen D.
Published: December 2015

We present the first on-chip atomisation-like production of phase-change contrast agents at high concentrations towards high-resolution contrast imaging for diagnostic ultrasound.
Characterization of calcium oxalate crystal-induced changes in the secretome of U937 human monocytes
Authors: Sintiprungrat Kitisak , Singhto Nilubon , Thongboonkerd Visith
Published: December 2015

This is the first study to characterize changes in the secretome of human monocytes induced by calcium oxalate crystals.
Synthesis and biological evaluation ofd-gluconhydroximo-1,5-lactam and its oxime-substituted derivatives as pharmacological chaperones for the treatment of Gaucher disease
Authors: Wang Jiajia , Wang Xiaomin , Zhao Yunyan , Ma Xiaoyao , Wan Yue , Chen Zhongwei , Chen Hao , Gan Hao , Li Jing , Li Lei , Wang Peng George , Zhao Wei
Published: December 2015

38was an efficient pharmacological chaperone for GCase-related cell line N370S, which can effectively promote the activity of the mutant protein by 1.93-fold at 12.5 μM.
Comparative metalloproteomic approaches for the investigation proteins involved in the toxicity of inorganic and organic forms of mercury in rice (Oryza sativa L.) roots
Authors: Li Yunyun , Zhao Jiating , Li Yu-Feng , Xu Xiaohan , Zhang Bowen , Liu Yongjie , Cui Liwei , Li Bai , Gao Yuxi , Chai Zhifang
Published: December 2015

The toxicity mechanisms of rice roots under inorganic mercury (IHg) or methylmercury (MeHg) stress were investigated using metalloproteomic approaches.
The dual roles of functional groups in the photoluminescence of graphene quantum dots
Authors: Wang Shujun , Cole Ivan S. , Zhao Dongyuan , Li Qin
Published: December 2015

This study reveals oxygenated functional groups play two roles in the photoluminescence of GQDs: introduce self-orbitals and induce mid-gap energy states.
Luminescence quantum yields of gold nanoparticles varying with excitation wavelengths
Authors: Cheng Yuqing , Lu Guowei , He Yingbo , Shen Hongming , Zhao Jingyi , Xia Keyu , Gong Qihuang
Published: December 2015

The photoluminescence quantum yields of gold nanoparticles, nanorods and nanobipyramids are excitation wavelength dependent.
Biosorption of Pb(ii) and Fe(iii) from aqueous co-solutions using chemically pretreated oil palm fronds
Authors: Khosravihaftkhany Shabnam , Morad Norhashimah , Abdullah Ahmad Zuhairi , Teng Tjoon Tow , Ismail Norli
Published: December 2015

The removal of Pb(ii) and Fe(iii) from aqueous solutions using specially pretreated oil palm fronds (OPF) as biosorbents was investigated.
Nitrogen-doped carbon nanotubes for sensitive and selective determination of heavy metals
Authors: Joshi Anju , Nagaiah Tharamani C.
Published: December 2015

The present study attempts to demonstrate the potential of nitrogen doped carbon nanotubes for electrochemical determination of heavy metal ions (especially Pb and Cd) without any prior pre-concentration step.
A double network strategy to improve epithelization of a poly(2-hydroxyethyl methacrylate) hydrogel for corneal repair application
Authors: Wang Lei , Lu Conglie , Liu Huihua , Lin Sen , Nan Kaihui , Chen Hao , Li Lingli
Published: December 2015

This paper presents a novel double network scaffold and its preparation methods, in which a cell-affinitive hydrogel was made by poly(2-hydroxyethyl methacrylate) and modified gelatin.
Development of nordihydroguaiaretic acid derivatives as potential multidrug-resistant selective agents for cancer treatment
Authors: Huang Lin-Chiang Sherlock , Chuang Hong , Kapoor Mohit , Hsieh Cheng-Ying , Chou Shih-Ching , Lin Hui-Hsien , Chen Yi-Wei , Chang Chia-Ching , Hwu Jih-Ru , Liang Yu-Chuan , Hsu Ming-Hua
Published: December 2015

A new series of nordihydroguaiaretic acid (NDGA) derivatives have been synthesized for the research of multidrug resistance (MDR) in cancer.
Elucidation of molecular interactions between a DBU based protic ionic liquid and organic solvents: thermophysical and computational studies
Authors: Singh Dharmendra , Singh Vickramjeet , Islam Nasarul , Gardas Ramesh L.
Published: December 2015

Energy profile of 1,8-diazabicyclo[5.4.0]undec-7-en-8-ium trifluoroacetate [DBUTFA].
Highly efficient performance of activated carbon impregnated with Ag, ZnO and Ag/ZnO nanoparticles as antimicrobial materials
Authors: Prashantha Kumar T. K. M. , Mandlimath Triveni R. , Sangeetha P. , Sakthivel P. , Revathi S. K. , Ashok Kumar S. K. , Sahoo Suban K.
Published: December 2015

Materials for biological contacts.
A rhodamine based “turn-on” fluorescent probe for Pb(ii) and live cell imaging
Authors: Sunnapu Omprakash , Kotla Niranjan G. , Maddiboyina Balaji , Singaravadivel Subramanian , Sivaraman Gandhi
Published: December 2015

A novel “turn-on” fluorescent chemosensor RDP-1 based on rhodamine tri methoxy benzaldehyde conjugate was synthesized, which showed high selectivity and sensitivity towards recognition of Pb2+in aqueous media.
Investigating the stability of gold nanorods modified with thiol molecules for biosensing
Authors: Gong Yongxiang , Liu Jian , Liu Runcong , Wang Jiaojiao , Niu Chunmei , Zhu Wenfeng , Xu Dongmei , Hu Zhongbo , Li Min , Zhao Yuliang
Published: December 2015

Studying the stability of centrifugated gold nanorods unmodified/modified with thiols.
Design, synthesis, and characterization of α,ω-disubstituted indeno[1,2-b]fluorene-6,12-dione-thiophene molecular semiconductors. Enhancement of ambipolar charge transport through synthetic tailoring of alkyl substituents
Authors: Ozdemir Mehmet , Choi Donghee , Kwon Guhyun , Zorlu Yunus , Kim Hyekyoung , Kim Myung-Gil , Seo SungYong , Sen Unal , Citir Murat , Kim Choongik , Usta Hakan
Published: December 2015

A series of novel solution-processable α,ω-disubstituted indeno[1,2-b]fluorene-6,12-dione-thiophene ambipolar semiconductors were developed and characterized in OTFT devices with favorable charge-transport properties.
Phosphonium based ionic liquids-stabilizing or destabilizing agents for collagen?
Authors: Tarannum Aafiya , Muvva Charuvaka , Mehta Ami , Rao J. Raghava , Fathima N. Nishad
Published: December 2015

The role of cations and anions of ionic liquids in the destabilization of collagen has been elucidated.
Phenylselanyl-1H-1,2,3-triazole-4-carbonitriles: synthesis, antioxidant properties and use as precursors to highly functionalized tetrazoles
Authors: Savegnago Lucielli , Sacramento Manoela do , Brod Lucimar M. P. , Fronza Mariana G. , Seus Natália , Lenardão Eder J. , Paixão Márcio W. , Alves Diego
Published: December 2015

We describe herein our results on the synthesis, antioxidant properties and chemical diversification of phenylselanyl-1H-1,2,3-triazole-4-carbonitriles.
Cobalt oxide nanoparticle embedded N-CNTs: lithium ion battery applications
Authors: Khan I. A. , Nasim F. , Choucair M. , Ullah S. , Badshah A. , Nadeem M. A.
Published: December 2015

ZIF-12 is converted to Co/N-CNTs at 950 °C under an argon atmosphere. The obtained hybrid nanocomposite is used for LIBs application as an anode material with superior charge storage performance.
Use of morphological features of carbonaceous materials for improved mechanical properties of epoxy nanocomposites
Authors: Atif R. , Wei J. , Shyha I. , Inam F.
Published: December 2015

The mechanical properties of epoxy nanocomposites can be significantly altered by tailoring the morphological features of carbonaceous fillers.
Coarse-grained molecular simulations of the melting kinetics of small unilamellar vesicles
Authors: Patel Lara A. , Kindt James T.
Published: December 2015

Frozen lipid vesicles simulated using a coarse-grained potential and subject to temperature jumps respond by melting on timescales similar to those observed experimentally; changes in curvature stress appear to play a dominant role in controlling the melting rate.
Spontaneous vesicle formation in a deep eutectic solvent
Authors: Bryant Saffron J. , Atkin Rob , Warr Gregory G.
Published: December 2015

Solvent penetration experiments and small-angle X-ray scattering reveal that phospholipids dissolved in a deep eutectic solvent (DES) spontaneously self-assemble into vesicles above the lipid chain melting temperature.
Bismuth-catalyzed and doped p-type ZnSe nanowires and their temperature-dependent charge transport properties
Authors: Zhang Xiwei , Jie Jiansheng , Zhang Xiujuan , Yu Fengjun
Published: December 2015

Simultaneous ZnSe nanowire growth and p-type doping is realized in one step by using Bi as the catalyst and dopant via chemical vapor deposition. Temperature-dependent electrical measurements are used for understanding the charge transport mechanism and the doping effect.
Novel fluorinated polycarbonate negative-type photoresists for thermo-optic waveguide gate switch arrays
Authors: Cai Zhenzhen , Wang Baolong , Zheng Yang , Li Ming , Li Yao , Chen Changming , Zhang Daming , Cui Zhanchen , Shi Zuosen
Published: December 2015

A series of direct-UV-written NFPRs based on AF-Z-PC EPs were prepared and used to fabricate MZI TO waveguide switch arrays.
Progress in Primary Aldosteronism: Translation on the
Move
Authors: Reincke M. , Beuschlein F.
Published: December 2015

Hypertension is a major cardiovascular risk factor that affects between 10–40% of
the general population in an age dependent manner. The
renin-angiotensin-aldosterone system (RAAS) regulates blood pressure, fluid
volume, and the vascular response to injury and inflammation 1. Chronic RAAS activation in the presence
of sufficient sodium consumption leads to persistent hypertension, setting off a
cascade of inflammatory, thrombotic, and atherogenic effects eventually leading
to end-organ damage 2
3. Accordingly, numerous studies have
demonstrated that elevated renin and/or aldosterone levels are predictors of
adverse outcome in hypertension 4, heart
failure 5
6, myocardial infarction 7, and renal insufficiency 8 and influence insulin resistance 9. Primary aldosteronism (PA) is the most
common secondary form of hypertension with an estimated prevalence between 4 and
12% of hypertensives 10
11
12 and 11–20% in patients that are resistant to combined
antihypertensive medication 13
14. Given the severe cardiovascular
adverse effects of aldosterone excess that are independent of high blood
pressure levels 15
16
17
18 detection and treatment
of PA has important impact on clinical outcome and survival.
Snowfall and a stolen laptop
Authors: McLaughlin Mark-David J , Hansen Sean , Cram W Alec , Gogan Janis L
Published: December 2015

The E. Phillip Saunders College of Business (COB) Dean at Rochester Institute of Technology (RIT) discovers that his RIT-issued laptop has been stolen from his home. He notifies Dave Ballard, a member of the College of Business IT staff. Ballard, still acutely aware of two recent incidents in which laptops containing thousands of Social Security numbers were stolen from the RIT campus, hopes the Dean's laptop does not contain personally identifiable information. If so, the incident would need to be reported to the New York Attorney General's Office, and RIT would be required to pay for a credit monitoring service for individuals whose identity may have been compromised. The case provides an opportunity for students to examine processes that should be triggered when an information security incident occurs. The case describes incident response processes that were triggered at RIT and technologies that were used or could have been used by COB IT staff to track the laptop and protect its contents. In discussing the case, students can consider how the theft of a computing device exposes an organization to risks of inadvertent disclosure of information in different categories (such as private, confidential, internal, or public), and students can derive useful guidelines for effective information security incident response.
Calibration of BAS-TR image plate response to high energy (3-300 MeV) carbon ions
Authors: Doria D. , Kar S. , Ahmed H. , Alejo A. , Fernandez J. , Cerchez M. , Gray R. J. , Hanton F. , MacLellan D. A. , McKenna P. , Najmudin Z. , Neely D. , Romagnani L. , Ruiz J. A. , Sarri G. , Scullion C. , Streeter M. , Swantusch M. , Willi O. , Zepf M. , Borghesi M.
Published: December 2015

The paper presents the calibration of Fuji BAS-TR image plate (IP) response to high energy carbon ions of different charge states by employing an intense laser-driven ion source, which allowed access to carbon energies up to 270 MeV. The calibration method consists of employing a Thomson parabola spectrometer to separate and spectrally resolve different ion species, and a slotted CR-39 solid state detector overlayed onto an image plate for an absolute calibration of the IP signal. An empirical response function was obtained which can be reasonably extrapolated to higher ion energies. The experimental data also show that the IP response is independent of ion charge states.
Many-body Green’s function theory for electron-phonon interactions: Ground state properties of the Holstein dimer
Authors: Säkkinen Niko , Peng Yang , Appel Heiko , van Leeuwen Robert
Published: December 2015

We study ground-state properties of a two-site, two-electron Holstein model describing two molecules coupled indirectly via electron-phonon interaction by using both exact diagonalization and self-consistent diagrammatic many-body perturbation theory. The Hartree and self-consistent Born approximations used in the present work are studied at different levels of self-consistency. The governing equations are shown to exhibit multiple solutions when the electron-phonon interaction is sufficiently strong, whereas at smaller interactions, only a single solution is found. The additional solutions at larger electron-phonon couplings correspond to symmetry-broken states with inhomogeneous electron densities. A comparison to exact results indicates that this symmetry breaking is strongly correlated with the formation of a bipolaron state in which the two electrons prefer to reside on the same molecule. The results further show that the Hartree and partially self-consistent Born solutions obtained by enforcing symmetry do not compare well with exact energetics, while the fully self-consistent Born approximation improves the qualitative and quantitative agreement with exact results in the same symmetric case. This together with a presented natural occupation number analysis supports the conclusion that the fully self-consistent approximation describes partially the bipolaron crossover. These results contribute to better understanding how these approximations cope with the strong localizing effect of the electron-phonon interaction.
Generation of a pulsed low-energy electron beam using the channel spark device
Authors: Elgarhy M. A. I. , Hassaballa S. E. , Rashed U. M. , ElSabbagh M. M. , Soliman H. M. , Saudy A. H.
Published: December 2015

For the generation of low-energy electron beam, the design and characteristics of channel spark discharge (CSD) operating at a low voltage are presented in this paper. The discharge voltage, discharge current, X-ray emissions, and electron beam current were experimentally determined. The effects of the applied voltage, working gas pressure, and external capacitance on the CSD and beam parameters were measured. At an applied voltage of 11 kV, an oxygen gas pressure of 25 mTorr, and an external capacitance of 16.45 nF, the maximum measured current was 900 A. The discharge current increased with the increase in the pressure and capacitance, while its periodic time decreased with the increase in the pressure. Two types of the discharge were identified and recorded: the hollow cathode discharge and the conduction discharge. A Faraday cup was used to measure the beam current. The maximum measured beam current was 120 A, and the beam signal exhibited two peaks. The increase in both the external capacitance and the applied discharge voltage increased the maximum electron beam current. The electron-beam pulse time decreased with the increase in the gas pressure at a constant voltage and increased with the decrease in the applied discharge voltage. At an applied voltage of 11 kV and an oxygen gas pressure of 15 mTorr, the maximum beam energy was 2.8 keV. The X-ray signal intensity decreased with the increase in the gas pressure and increased with the increase in the capacitance.
Magnetization states of canted antiferromagnetic YFeO3 investigated by terahertz time-domain spectroscopy
Authors: Kim T. H. , Kang C. , Kee C.-S. , Lee J.-H. , Cho B. K. , Gruenberg P. , Tokunaga Y. , Tokura Y. , Lee J. S.
Published: December 2015

We investigate magnetization states of a canted antiferromagnetic YFeO3 by using terahertz (THz) time-domain spectroscopy under a variation of an external magnetic field. As a quasi-ferromagnetic mode near 0.3 THz is excited by the magnetic field of the THz pulse, a precession of the magnetic moment and its induction decay radiate the THz wave. Since oppositely aligned magnetic domains emit the circularly/elliptically polarized THz waves with opposite helicities, a detection of specific polarization of the THz wave shows a clear hysteresis behavior in good agreement with a magnetization curve obtained as a function of the applied magnetic field. Furthermore, time-domain measurement of excited magnetic moment can provide direct information about the magnetization decay dynamics.
Modulational stability of weakly nonlinear wave-trains in media with small- and large-scale dispersions
Authors: Nikitenkova S. , Singh N. , Stepanyants Y.
Published: December 2015

In this paper, we revisit the problem of modulation stability of quasi-monochromatic wave-trains propagating in a media with the double dispersion occurring both at small and large wavenumbers. We start with the shallow-water equations derived by Shrira [Izv., Acad. Sci., USSR, Atmos. Ocean. Phys. (Engl. Transl.) 17, 55–59 (1981)] which describes both surface and internal long waves in a rotating fluid. The small-scale (Boussinesq-type) dispersion is assumed to be weak, whereas the large-scale (Coriolis-type) dispersion is considered as without any restriction. For unidirectional waves propagating in one direction, only the considered set of equations reduces to the Gardner–Ostrovsky equation which is applicable only within a finite range of wavenumbers. We derive the nonlinear Schrödinger equation (NLSE) which describes the evolution of narrow-band wave-trains and show that within a more general bi-directional equation the wave-trains, similar to that derived from the Ostrovsky equation, are also modulationally stable at relatively small wavenumbers k < kc and unstable at k > kc, where kc is some critical wavenumber. The NLSE derived here has a wider range of applicability: it is valid for arbitrarily small wavenumbers. We present the analysis of coefficients of the NLSE for different signs of coefficients of the governing equation and compare them with those derived from the Ostrovsky equation. The analysis shows that for weakly dispersive waves in the range of parameters where the Gardner–Ostrovsky equation is valid, the cubic nonlinearity does not contribute to the nonlinear coefficient of NLSE; therefore, the NLSE can be correctly derived from the Ostrovsky equation.
Nonlinear electronic excitations in crystalline solids using meta-generalized gradient approximation and hybrid functional in time-dependent density functional theory
Authors: Sato Shunsuke A. , Taniguchi Yasutaka , Shinohara Yasushi , Yabana Kazuhiro
Published: December 2015

We develop methods to calculate electron dynamics in crystalline solids in real-time time-dependent density functional theory employing exchange-correlation potentials which reproduce band gap energies of dielectrics; a meta-generalized gradient approximation was proposed by Tran and Blaha [Phys. Rev. Lett. 102, 226401 (2009)] (TBm-BJ) and a hybrid functional was proposed by Heyd, Scuseria, and Ernzerhof [J. Chem. Phys. 118, 8207 (2003)] (HSE). In time evolution calculations employing the TB-mBJ potential, we have found it necessary to adopt the predictor-corrector step for a stable time evolution. We have developed a method to evaluate electronic excitation energy without referring to the energy functional which is unknown for the TB-mBJ potential. For the HSE functional, we have developed a method for the operation of the Fock-like term in Fourier space to facilitate efficient use of massive parallel computers equipped with graphic processing units. We compare electronic excitations in silicon and germanium induced by femtosecond laser pulses using the TB-mBJ, HSE, and a simple local density approximation (LDA). At low laser intensities, electronic excitations are found to be sensitive to the band gap energy: they are close to each other using TB-mBJ and HSE and are much smaller in LDA. At high laser intensities close to the damage threshold, electronic excitation energies do not differ much among the three cases.
Exploring mechanisms of a tropospheric archetype: CH3O2 + NO
Authors: Launder Andrew M. , Agarwal Jay , Schaefer Henry F.
Published: December 2015

Methylperoxy radical (CH3O2) and nitric oxide (NO) contribute to the propagation of photochemical smog in the troposphere via the production of methoxy radical (CH3O) and nitrogen dioxide (NO2). This reaction system also furnishes trace quantities of methyl nitrate (CH3ONO2), a sink for reactive NOx species. Here, the CH3O2 + NO reaction is examined with highly reliable coupled-cluster methods. Specifically, equilibrium geometries for the reactants, products, intermediates, and transition states of the ground-state potential energy surface are characterized. Relative reaction enthalpies at 0 K (ΔH0K) are reported; these values are comprised of electronic energies extrapolated to the complete basis set limit of CCSDT(Q) and zero-point vibrational energies computed at CCSD(T)/cc-pVTZ. A two-part mechanism involving CH3O and NO2 production followed by radical recombination to CH3ONO2 is determined to be the primary channel for formation of CH3ONO2 under tropospheric conditions. Constrained optimizations of the reaction paths at CCSD(T)/cc-pVTZ suggest that the homolytic bond dissociations involved in this reaction path are barrierless.
Are protein-protein interfaces special regions on a protein’s surface?
Authors: Tonddast-Navaei Sam , Skolnick Jeffrey
Published: December 2015

Protein-protein interactions (PPIs) are involved in many cellular processes. Experimentally obtained protein quaternary structures provide the location of protein-protein interfaces, the surface region of a given protein that interacts with another. These regions are termed half-interfaces (HIs). Canonical HIs cover roughly one third of a protein’s surface and were found to have more hydrophobic residues than the non-interface surface region. In addition, the classical view of protein HIs was that there are a few (if not one) HIs per protein that are structurally and chemically unique. However, on average, a given protein interacts with at least a dozen others. This raises the question of whether they use the same or other HIs. By copying HIs from monomers with the same folds in solved quaternary structures, we introduce the concept of geometric HIs (HIs whose geometry has a significant match to other known interfaces) and show that on average they cover three quarters of a protein’s surface. We then demonstrate that in some cases, these geometric HI could result in real physical interactions (which may or may not be biologically relevant). The composition of the new HIs is on average more charged compared to most known ones, suggesting that the current protein interface database is biased towards more hydrophobic, possibly more obligate, complexes. Finally, our results provide evidence for interface fuzziness and PPI promiscuity. Thus, the classical view of unique, well defined HIs needs to be revisited as HIs are another example of coarse-graining that is used by nature.
Comparative analyses of plasma probe diagnostics techniques
Authors: Godyak V. A. , Alexandrovich B. M.
Published: December 2015

The subject of this paper is a comparative analysis of the plasma parameters inferred from the classical Langmuir probe procedure, from different theories of the ion current to the probe, and from measured electron energy distribution function (EEDF) obtained by double differentiation of the probe characteristic. We concluded that the plasma parameters inferred from the classical Langmuir procedure can be subjected to significant inaccuracy due to the non-Maxwellian EEDF, uncertainty of locating the plasma potential, and the arbitrariness of the ion current approximation. The plasma densities derived from the ion part of the probe characteristics diverge by as much as an order of magnitude from the density calculated according to Langmuir procedure or calculated as corresponding integral of the measured EEDF. The electron temperature extracted from the ion part is always subjected to uncertainty. Such inaccuracy is attributed to modification of the EEDF for fast electrons due to inelastic electron collisions, and to deficiencies in the existing ion current theories; i.e., unrealistic assumptions about Maxwellian EEDFs, underestimation of the ion collisions and the ion ambipolar drift, and discounting deformation of the one-dimensional structure of the region perturbed by the probe. We concluded that EEDF measurement is the single reliable probe diagnostics for the basic research and industrial applications of highly non-equilibrium gas discharge plasmas. Examples of EEDF measurements point up importance of examining the probe current derivatives in real time and reiterate significance of the equipment technical characteristics, such as high energy resolution and wide dynamic range.
Dislocation core structures in Si-doped GaN
Authors: Rhode S. L. , Horton M. K. , Fu W. Y. , Sahonta S.-L. , Kappers M. J. , Pennycook T. J. , Humphreys C. J. , Dusane R. O. , Moram M. A.
Published: December 2015

Aberration-corrected scanning transmission electron microscopy was used to investigate the core structures of threading dislocations in plan-view geometry of GaN films with a range of Si-doping levels and dislocation densities ranging between (5 ± 1) × 108 and (10 ± 1) × 109 cm−2. All a-type (edge) dislocation core structures in all samples formed 5/7-atom ring core structures, whereas all (a + c)-type (mixed) dislocations formed either double 5/6-atom, dissociated 7/4/8/4/9-atom, or dissociated 7/4/8/4/8/4/9-atom core structures. This shows that Si-doping does not affect threading dislocation core structures in GaN. However, electron beam damage at 300 keV produces 4-atom ring structures for (a + c)-type cores in Si-doped GaN.
Influence of dust particles on the bulk electron density in radio frequency plasmas measured by microwave interferometry
Authors: Killer Carsten , Wegner Thomas , Melzer André , Meichsner Jürgen
Published: December 2015

The influence of dust particles, inserted in the rf plasma sheath of a capacitively coupled argon plasma, on the bulk electron density is investigated. The line integrated electron density has been measured using 160 GHz Gaussian beam microwave interferometry. A significant electron density increase compared to the dust free plasma was observed for high number densities of larger dust particles (d=12.3 μm). Furthermore, the rising electron density is combined with increasing optical plasma emission. For smaller dust particles (d=3.6 μm), no clear effect, but a tendency to a weak electron density reduction, was found. The results are compared to previous simulations of the impact ionization and excitation in dusty plasmas.
Two-dimensional simulation of spatiotemporal generation of dielectric barrier columnar discharges in atmospheric helium
Authors: Huang Zhiming , Hao Yanpeng , Yang Lin , Han Yongxia , Li Licheng
Published: December 2015

A two-dimensional (2D) fluid model is presented to investigate the spatiotemporal generation and dynamic mechanics of dielectric barrier columnar discharges in atmospheric helium. The model was examined with discharge currents measured in experiments and images taken by an intensified charge couple device camera. Based on the model, a columnar discharge was simulated for several cycles after being ignited. The discharge could be regarded as an initial unstable stage for the first three and a half cycles, then a steady state for the following cycles. In the initial stage, the discharge evolves from a uniform pattern into a columnar one. The calculated equipotential lines, 2D radial electric field, and electron density distributions at the edge of uniform discharges show the radial electric field accounts for the shrinking discharge area and the formation of discharge columns in the end. The columnar glow discharges and the Townsend discharges beyond the columns could coexist in the initial stage, and a Townsend discharge might develop into a new glow column in the next half-cycle. The radial electric field surrounding a glow discharge column has an inhibiting effect on the ionization in the peripheral area.
Targeted energy transfers and passive acoustic wave redirection in a two-dimensional granular network under periodic excitation
Authors: Zhang Yijing , Moore Keegan J. , McFarland D. Michael , Vakakis Alexander F.
Published: December 2015

We study passive pulse redirection and nonlinear targeted energy transfer in a granular network composed of two semi-infinite, ordered homogeneous granular chains mounted on linear elastic foundations and coupled by weak linear stiffnesses. Periodic excitation in the form of repetitive half-sine pulses is applied to one of the chains, designated as the “excited chain,” whereas the other chain is initially at rest and is regarded as the “absorbing chain.” We show that passive pulse redirection and targeted energy transfer from the excited to the absorbing chain can be achieved by macro-scale realization of the spatial analog of the Landau-Zener quantum tunneling effect. This is realized by finite stratification of the elastic foundation of the excited chain and depends on the system parameters (e.g., the percentage of stratification) and on the parameters of the periodic excitation. Utilizing empirical mode decomposition and numerical Hilbert transforms, we detect the existence of two distinct nonlinear phenomena in the periodically forced network; namely, (i) energy localization in the absorbing chain due to sustained 1:1 resonance capture leading to irreversible pulse redirection from the excited chain, and (ii) continuous energy exchanges in the form of nonlinear beats between the two chains in the absence of resonance capture. Our results extend previous findings of transient passive energy redirection in impulsively excited granular networks and demonstrate that steady state passive pulse redirection in these networks can be robustly achieved under periodic excitation.
Focusing adaptive-optics for neutron spectroscopy at extreme conditions
Authors: Simeoni G. G. , Valicu R. G. , Borchert G. , Böni P. , Rasmussen N. G. , Yang F. , Kordel T. , Holland-Moritz D. , Kargl F. , Meyer A.
Published: December 2015

Neutron Spectroscopy employing extreme-conditions sample environments is nowadays a crucial tool for the understanding of fundamental scientific questions as well as for the investigation of materials and chemical-physical properties. For all these kinds of studies, an increased neutron flux over a small sample area is needed. The prototype of a focusing neutron guide component, developed and produced completely at the neutron source FRM II in Garching (Germany), has been installed at the time-of-flight (TOF) disc-chopper neutron spectrometer TOFTOF and came into routine-operation. The design is based on the compressed Archimedes' mirror concept for finite-size divergent sources. It represents a unique device combining the supermirror technology with Adaptive Optics, suitable for broad-bandwidth thermal-cold TOF neutron spectroscopy (here optimized for 1.4–10 Å). It is able to squeeze the beam cross section down to a square centimeter, with a more than doubled signal-to-background ratio, increased efficiency at high scattering angles, and improved symmetry of the elastic resolution function. We present a comparison between the simulated and measured beam cross sections, as well as the performance of the instrument within real experiments. This work intends to show the unprecedented opportunities achievable at already existing instruments, along with useful guidelines for the design and construction of next-generation neutron spectrometers.
Control of acoustic absorption in one-dimensional scattering by resonant scatterers
Authors: Merkel A. , Theocharis G. , Richoux O. , Romero-García V. , Pagneux V.
Published: December 2015

We experimentally report perfect acoustic absorption through the interplay of the inherent losses and transparent modes with high Q factor. These modes are generated in a two-port, one-dimensional waveguide, which is side-loaded by isolated resonators of moderate Q factor. In symmetric structures, we show that in the presence of small inherent losses, these modes lead to coherent perfect absorption associated with one-sided absorption slightly larger than 0.5. In asymmetric structures, near perfect one-sided absorption is possible (96%) with a deep sub-wavelength sample (λ/28, where λ is the wavelength of the sound wave in the air). The control of strong absorption by the proper tuning of the radiation leakage of few resonators with weak losses will open possibilities in various wave-control devices.
Note: Measuring spectral response of photocells with light-emitting diodes
Authors: Tada Kazuya , Tanaka Hiroaki
Published: December 2015

Although the spectral response is a key data for photocells, traditional measurement setup for it consists of expensive optical precision components including white-light source, collimator and monochromator, and has relatively large footprint. Here, it is demonstrated that a compact, portable, and low-cost device based on an array of light-emitting diodes can provide quantitatively reliable spectral response characterization of photocells. The device seems to be useful for the purpose of preliminary survey of the spectral response of novel material and/or materials system prior to precise measurement with the traditional equipment.
Influence of the Mississippi River plume and non-bioavailable DMSP on dissolved DMSP turnover in the northern Gulf of Mexico
Authors: Motard-Côté Jessie , Kieber David J. , Rellinger Allison , Kiene Ronald P.
Published: December 2015

Environmental contextDimethylsulfoniopropionate (DMSP) comprises an important fraction of the organic carbon produced by phytoplankton, and is a major source of carbon and sulfur for heterotrophic bacteria. Here, we show that a non-bioavailable fraction of DMSP recently discovered in coastal waters also exists in oligotrophic open-ocean waters. Taking account of the non-bioavailable pool improved estimates of cycling rates of DMSP and its contribution to bacterial nutrition. AbstractMicrobial cycling of dissolved dimethylsulfoniopropionate (DMSPd) and the fate of DMSP-sulfur were measured in the northern Gulf of Mexico off the Louisiana coast in September 2011 using the tracer 35S-DMSPd. Salinity ranged from 31.2ppt in the Mississippi River plume to 36.5ppt offshore. Total DMSP concentrations were significantly higher at the river-influenced stations (12–27nM) than offshore (6–14nM). From 8.7 to 27% of the measured DMSPd, equivalent to 0.1 to 0.23nM, was refractory (i.e. non-bioavailable). We subtracted refractory DMSPd from the measured DMSPd concentrations when calculating DMSPd consumption rates with the tracer 35S-DMSPd. DMSPd consumption and bacterial production were respectively 8 and 7 times higher in the river plume compared with offshore. Incorporation of DMSP-sulfur into biomass was almost three times higher in river-influenced water, whereas the dimethylsulfide (DMS) yield was 3.5 times lower in the river plume compared with offshore. Accordingly, DMSP contributed over 3 times more to the bacterial demand for both carbon and sulfur in the river-influenced water. Despite lower DMS yields in the river plume, the fast DMSP turnover resulted in a 2.7-times higher DMS production compared with offshore waters. Mississippi River inputs and the resulting high productivity led to a rapid turnover of DMSP and high DMS production in the river plume compared with oligotrophic Gulf of Mexico waters. Failure to account for refractory DMSPd when using the 35S-DMSP method will lead to significant overestimation of the DMSPd turnover flux and its contributions to C and S cycling.
Changing recruitment capacity in global fish stocks
Authors: Britten Gregory L. , Dowd Michael , Worm Boris
Published: December 2015

Significance

Marine fish stocks play an important role in marine ecosystems and provide a source of protein for billions of people worldwide. Recent environmental changes have affected the distribution of many stocks, but it is yet unclear whether their productivity is affected as well. We show that recruitment capacity (the ability of stocks to produce surviving offspring) has been significantly altered by both environmental changes and biological changes brought about by overfishing. In total, these effects have reduced recruitment capacity by 3% of the historical maximum per decade, on average. This paper helps us to understand and track previously unrecognized changes in fish stock productivity during the early stages of their life cycle.