bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions between growth-dependent changes in cell size, nutrient supply and cellular elemental stoichiometry of marine Synechococcus
Authors: Garcia Nathan S , Bonachela Juan A , Martiny Adam C
Published: April 2016

The factors that control elemental ratios within phytoplankton, like carbon:nitrogen:phosphorus (C:N:P), are key to biogeochemical cycles. Previous studies have identified relationships between nutrient-limited growth and elemental ratios in large eukaryotes, but little is known about these interactions in small marine phytoplankton like the globally important Cyanobacteria. To improve our understanding of these interactions in picophytoplankton, we asked how cellular elemental stoichiometry varies as a function of steady-state, N- and P-limited growth in laboratory chemostat cultures of Synechococcus WH8102. By combining empirical data and theoretical modeling, we identified a previously unrecognized factor (growth-dependent variability in cell size) that controls the relationship between nutrient-limited growth and cellular elemental stoichiometry. To predict the cellular elemental stoichiometry of phytoplankton, previous theoretical models rely on the traditional Droop model, which purports that the acquisition of a single limiting nutrient suffices to explain the relationship between a cellular nutrient quota and growth rate. Our study, however, indicates that growth-dependent changes in cell size have an important role in regulating cell nutrient quotas. This key ingredient, along with nutrient-uptake protein regulation, enables our model to predict the cellular elemental stoichiometry of Synechococcus across a range of nutrient-limited conditions. Our analysis also adds to the growth rate hypothesis, suggesting that P-rich biomolecules other than nucleic acids are important drivers of stoichiometric variability in Synechococcus. Lastly, by comparing our data with field observations, our study has important ecological relevance as it provides a framework for understanding and predicting elemental ratios in ocean regions where small phytoplankton like Synechococcus dominates.
FTIR spectroscopic imaging and mapping with correcting lenses for studies of biological cells and tissues
Authors: Kimber James A. , Foreman Liberty , Turner Benjamin , Rich Peter , Kazarian Sergei G.
Published: April 2016

Histopathology of tissue samples is used to determine the progression of cancer usually by staining and visual analysis. It is recognised that disease progression from healthy tissue to cancerous is accompanied by spectral signature changes in the mid-infrared range. In this work, FTIR spectroscopic imaging in transmission mode using a focal plane array (96 × 96 pixels) has been applied to the characterisation of Barrett's oesophageal adenocarcinoma. To correct optical aberrations, infrared transparent lenses were used of the same material (CaF2) as the slide on which biopsies were fixed. The lenses acted as an immersion objective, reducing scattering and improving spatial resolution. A novel mapping approach using a sliding lens is presented where spectral images obtained with added lenses are stitched together such that the dataset contained a representative section of the oesophageal tissue. Images were also acquired in transmission mode using high-magnification optics for enhanced spatial resolution, as well as with a germanium micro-ATR objective. The reduction of scattering was assessed using k-means clustering. The same tissue section map, which contained a region of high grade dysplasia, was analysed using hierarchical clustering analysis. A reduction of the trough at 1077 cm−1 in the second derivative spectra was identified as an indicator of high grade dysplasia. In addition, the spatial resolution obtained with the lens using high-magnification optics was assessed by measurements of a sharp interface of polymer laminate, which was also compared with that achieved with micro ATR-FTIR imaging. In transmission mode using the lens, it was determined to be 8.5 μm and using micro-ATR imaging, the resolution was 3 μm for the band at a wavelength of ca. 3 μm. The spatial resolution was also assessed with and without the added lens, in normal and high-magnification modes using a USAF target. Spectroscopic images of cells in transmission mode using two lenses are also presented, which are necessary for correcting chromatic aberration and refraction in both the condenser and objective. The use of lenses is shown to be necessary for obtaining high-quality spectroscopic images of cells in transmission mode and proves the applicability of the pseudo hemisphere approach for this and other microfluidic systems.
Silica mesophases intercalated by cross-linked micelles of a sustainable oleyl diamine surfactant and metal ion uptake properties thereof
Authors: Canlas Christian P. , Pinnavaia Thomas J.
Published: April 2016

Polymeric forms of eco-friendly oleyl diamine surfactant intercalated in silica are effective in binding Cu(ii) and Pb(ii) from aqueous solution.
Ca(OH)2nano-pods: investigation on the effect of solvent ratio on morphology and CO2adsorption capacity
Authors: Mohd Daud Farah Diana , Vignesh Kumaravel , Sreekantan Srimala , Mohamed Abdul Rahman , Kang Misook , Kwak Byeong Sub
Published: April 2016

A schematic diagram of the proposed mechanism of the formation of Ca(OH)2pod shapes by a precipitation route.
Development of portable defocusing micro-scale spatially offset Raman spectroscopy
Authors: Realini Marco , Botteon Alessandra , Conti Claudia , Colombo Chiara , Matousek Pavel
Published: April 2016

We present, for the first time, portable defocusing micro-Spatially Offset Raman Spectroscopy (micro-SORS).
Electrochemical determination of trace copper(ii) based onl-cysteine functionalized gold nanoparticle/CdS nanosphere hybrid
Authors: Li Lin-Gang , Chen Meng , Hao He-Qun , Xu Qing-Qing , Wu Ju , Xie Cheng-Gen , Fu Xu-Cheng
Published: April 2016

This paper describes a simple and efficient electrochemical assay for the determination of trace Cu(ii) employingl-cysteine functionalized gold nanoparticles/CdS nanospheres/glassy carbon electrode (l-cys/AuNPs/CdS/GCE) as an enhanced sensing platform.
Fast clean-up and selective enrichment of florfenicol in milk by restricted access media molecularly imprinted magnetic microspheres based on surface-initiated photoiniferter-mediated polymerization
Authors: Lv Yun-Kai , Zhang Jing , Li Meng-Zhe , Zhou Shao-Dan , Ren Xing-Hui , Wang Jing
Published: April 2016

A novel RAM-MIMM with water-compatible, exclusion biomacromolecules and selective enrichment analytes was prepared using a surface-initiated iniferter technique for magnetic dispersion extraction of trace florfenicol from milk samples.
Interface coassembly of mesoporous MoS2based-frameworks for enhanced near-infrared light driven photocatalysis
Authors: Zhi Lihua , Zhang Haoli , Yang Zhengyin , Liu Weisheng , Wang Baodui
Published: April 2016

The three-dimensional porous Fe3O4@Cu2−xS–MoS2framework is reported for the first time. Such a hybrid framework exhibits excellent NIR-light photocatalytic activity and stable cycling for the direct arylation of heteroaromatics at room temperature.
Controlling microenvironments and modifying anion binding selectivities using core functionalised hyperbranched polymers
Authors: Mann Georgia , Twyman Lance J. , Gale Philip A.
Published: April 2016

An isophthalamide anion binding site has been incorporated into hyperbranched polymers resulting in a change in the selectivity of the receptor from chloride to bromide.
Dihydrogen bond interactions as a result of H2cleavage at Cu, Ag and Au centres
Authors: Grabowski Sławomir J. , Ruipérez Fernando
Published: April 2016

Dihydrogen activation at M centres (M = Cu, Ag and Au) of metal fluorides, MF, leads to H2cleavage and the formation of a dihydrogen bonded complex in the cases of Cu and Ag. For the AuF + H2reaction, the complex linked through the Au⋯H interaction is formed.
Coarse-graining the structure of polycyclic aromatic hydrocarbons clusters
Authors: Hernández-Rojas J. , Calvo F. , Wales D. J.
Published: April 2016

Clusters of polycyclic aromatic hydrocarbons are essential components of soot and may concentrate a significant fraction of carbon matter in the interstellar medium.
Photochemical reaction dynamics of 2,2′-dithiobis(benzothiazole): direct observation of the addition product of an aromatic thiyl radical to an alkene with time-resolved vibrational and electronic absorption spectroscopy
Authors: Koyama Daisuke , Orr-Ewing Andrew J.
Published: April 2016

A carbon-centered intermediate radical of a thiol–ene reaction is directly probed on the picosecond time scale with time-resolved vibrational absorption spectroscopy.
Correction: Large-size nanosheets of 9,10-bis(phenylethynyl)anthracene with high photoresponse and light emission anisotropy
Authors: Wang Juan-Ye , Peng Hong-Dan , Yang Jia-Mei , Yan Jing-Hui , Pan Ge-Bo
Published: April 2016

Correction for ‘Large-size nanosheets of 9,10-bis(phenylethynyl)anthracene with high photoresponse and light emission anisotropy’ by Juan-Ye Wang et al., Phys. Chem. Chem. Phys., 2016, DOI: 10.1039/c5cp05507e.
Surface heterogeneity: a friend or foe of protein adsorption – insights from theoretical simulations
Authors: Penna Matthew , Ley Kamron , Maclaughlin Shane , Yarovsky Irene
Published: April 2016

A lack in the detailed understanding of mechanisms through which proteins adsorb or are repelled at various solid/liquid interfaces limits the capacity to rationally design and produce more sophisticated surfaces with controlled protein adsorption in both biomedical and industrial settings. To date there are three main approaches to achieve anti biofouling efficacy, namely chemically adjusting the surface hydrophobicity and introducing various degrees of surface roughness, or a combination of both. More recently, surface nanostructuring has been shown to have an effect on protein adsorption. However, the current resolution of experimental techniques makes it difficult to investigate these three phase systems at the molecular level. In this molecular dynamics study we explore in all-atom detail the adsorption process of one of the most surface active proteins, EAS hydrophobin, known for its versatile ability to self-assemble on both hydrophobic and hydrophilic surfaces forming stable monolayers that facilitate further biofilm growth. We model the adsorption of this protein on organic ligand protected silica surfaces with varying degrees of chemical heterogeneity and roughness, including fully homogenous hydrophobic and hydrophilic surfaces for comparison. We present a detailed characterisation of the functionalised surface structure and dynamics for each of these systems, and the effect the ligands have on interfacial water, the adsorption process and conformational rearrangements of the protein. Results suggest that the ligand arrangement that produces the highest hydrophilic chain mobility and the lack of significant hydrophobic patches shows the most promising anti-fouling efficacy toward hydrophobin. However, the presence on the protein surface of a flexible loop with amphipathic character (the Cys3–Cys4 loop) is seen to facilitate EAS adsorption on all surfaces by enabling the protein to match the surface pattern.
Motorized actuation system to perform droplet operations on printed plastic sheets
Authors: Kong Taejoon , Brien Riley , Njus Zach , Kalwa Upender , Pandey Santosh
Published: April 2016

An open microfluidic system is presented to manipulate discrete droplets on plastic sheets by using controlled, mechanical agitations.
MarRA, SoxSR, and Rob encode a signal dependent regulatory network in Escherichia coli
Authors: Jain Kirti , Saini Supreet
Published: April 2016

When exposed to low concentrations of toxic chemicals, bacteria modulate the expression of a number of cellular processes.
Development and design of the tertiary amino effect reaction for DNA-encoded library synthesis
Authors: Tian Xia , Basarab Gregory S. , Selmi Nidhal , Kogej Thierry , Zhang Ying , Clark Matthew , Goodnow Jr. Robert A.
Published: April 2016

The tertiary amino effect reaction was explored and developed for application to DNA-encoded library synthesis.
Recent developments in SAR visualization
Authors: Stumpfe Dagmar , Bajorath Jürgen
Published: April 2016

Shown is a section of an SAR network. Nodes represent compounds and are colored by potency and edges indicate pair-wise similarity relationships.
Porous Mn2O3 microcubes with exposed {001} facets as electrode for lithium ion batteries
Authors: Han Xiguang , Han Xiao , Li Rong , Sun Linqiang , Lu Kai , Wu Mengyao , Zhu Yuxuan , Zhao Xinsheng
Published: April 2016

Porous Mn2O3 microcubes with exposed {001} facets have been obtained and the Li-ion batteries in which they are applied deliver a high reversible capacity.
Nickel(ii), zinc(ii) and cadmium(ii) complexes of hexapeptides containing separate histidyl and cysteinyl binding sites
Authors: Raics Mária , Lihi Norbert , Laskai Aliz , Kállay Csilla , Várnagy Katalin , Sóvágó Imre
Published: April 2016

Hexapeptides containing separate histidyl and cysteinyl residues have outstanding metal binding ability but the binding sites of peptides reveal a significant specificity.
Electrospun nanofiber SLIPS exhibiting high total transparency and scattering
Authors: Abe Jyunichiro , Tenjimbayashi Mizuki , Shiratori Seimei
Published: April 2016

Antifouling coatings are important in fields such as mobility, architecture, power generation devices, and medical devices, where energy efficiency is required to be maximized.
13-Methyl-3,4-seco-ent-podocarpanes, rare C18-diterpenoids from the roots of Flueggea virosa
Authors: Chao Chih-Hua , Cheng Ju-Chien , Shen De-Yang , Huang Hui-Chi , Wu Yang-Chang , Wu Tian-Shung
Published: April 2016

13-Methyl-3,4-seco-ent-podocarpanes from F. virosa were characterized. Their structures were elucidated by extensive spectroscopic analysis. Compound 8 exhibited significant anti-HCV activity with a therapeutic index of 100.5.
The study on vascularisation and osteogenesis of BMP/VEGF co-modified tissue engineering bone in vivo
Authors: Jia Jiang , Siheng Wang , Fang Chai , Chengchong Ai , Shiyi Chen
Published: April 2016

To evaluate the osteogenic capacity of tissue engineering bonein vivoand compare the vascularization and osteogenesis between co- and single-modified tissue engineered bone.
In vitro/in vivo study of novel anti-cancer, biodegradable cross-linked tannic acid for fabrication of 5-fluorouracil-targeting drug delivery nano-device based on a molecular imprinted polymer
Authors: Asadi Ebadullah , Abdouss Majid , Leblanc Roger M. , Ezzati Noushin , Wilson James N. , Azodi-Deilami Saman
Published: April 2016

The structure of a 5-fluorouracil carrier and fluorescent image of an animal after injection under a magnetic field.
Rapid magnetic solid-phase extraction combined with ultra-high performance liquid chromatography and quadrupole-time-of-flight mass spectrometry for analysis of thrombin binders from a crude extract and injection of Erigeron breviscapus
Authors: Tao Yi , Jiang Yanhui , Li Weidong , Cai Baochang
Published: April 2016

Thrombin, which acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, plays crucial roles in the blood coagulation pathway.
Microstructure and magnetism of Co-doped PbPdO2 films with different grain sizes
Authors: Tang F. L. , Liu J. , Mei C. , Huang S. Y. , Song T. T. , Su H. L. , Lee M. K. , Wu Y. C. , Huang J. C. A.
Published: April 2016

The dependence of the magnetism of the Co-doped PbPdO2 nanograin films with peculiar spin-gapless-related feature on the grain size was studied in detail.
Engineering aggregation-induced SERS-active porous Au@ZnS multi-yolk–shell structures for visualization of guest species loading
Authors: Liu Jing , Chen Liyong , Duan Binhua , Gu Zhizhi , Luo Qiong , Duan Chunying
Published: April 2016

Herein, we present aggregation-induced surface-enhanced Raman scattering (SERS)-active hierarchical structures that effectively capture guest species loading in hollow nanocaged materials.
Microheterogeneity in binary mixtures of methanol with aliphatic alcohols: ATR-IR/NIR spectroscopic, chemometrics and DFT studies
Authors: Wrzeszcz Władysław , Tomza Paweł , Kwaśniewicz Michał , Mazurek Sylwester , Szostak Roman , Czarnecki Mirosław Antoni
Published: April 2016

This paper reports ATR-IR and NIR spectroscopic studies on microheterogeneity in binary mixtures of methanol with five short chain aliphatic alcohols: ethanol, 1-propanol, 2-propanol,tert-butanol and cyclopentanol.
N, S and P-ternary doped carbon nano-pore/tube composites derived from natural chemicals in waste sweet osmanthus fruit with superior activity for oxygen reduction in acidic and alkaline media
Authors: Liu Ziwu , Wang Fang , Li Meng , Ni Zhong-Hai
Published: April 2016

N, S and P-ternary doped carbon nano-pore/tube composites (NSP-CNPTCs) were prepared on the basis of natural chemicals from the waste sweet osmanthus fruit. Results indicated NSP-CNPTCs exhibited superior ORR activity in both acid and basic media.
Correction: Unravelling the chemical design of spin-crossover nanoparticles based on iron(ii)–triazole coordination polymers: towards a control of the spin transition
Authors: Giménez-Marqués Mónica , García-Sanz de Larrea M. Luisa , Coronado Eugenio
Published: April 2016

Correction for ‘Unravelling the chemical design of spin-crossover nanoparticles based on iron(ii)–triazole coordination polymers: towards a control of the spin transition’ by Mónica Giménez-Marqués et al., J. Mater. Chem. C, 2015, 3, 7946–7953.
A Comparison of the Visual Attention Patterns of People With Aphasia and Adults Without Neurological Conditions for Camera-Engaged and Task-Engaged Visual Scenes
Authors: Thiessen Amber , Beukelman David , Hux Karen , Longenecker Maria
Published: April 2016

Purpose

The purpose of the study was to compare the visual attention patterns of adults with aphasia and adults without neurological conditions when viewing visual scenes with 2 types of engagement.

Method

Eye-tracking technology was used to measure the visual attention patterns of 10 adults with aphasia and 10 adults without neurological conditions. Participants viewed camera-engaged (i.e., human figure facing camera) and task-engaged (i.e., human figure looking at and touching an object) visual scenes.

Results

Participants with aphasia responded to engagement cues by focusing on objects of interest more for task-engaged scenes than camera-engaged scenes; however, the difference in their responses to these scenes were not as pronounced as those observed in adults without neurological conditions. In addition, people with aphasia spent more time looking at background areas of interest and less time looking at person areas of interest for camera-engaged scenes than did control participants.

Conclusions

Results indicate people with aphasia visually attend to scenes differently than adults without neurological conditions. As a consequence, augmentative and alternative communication (AAC) facilitators may have different visual attention behaviors than the people with aphasia for whom they are constructing or selecting visual scenes. Further examination of the visual attention of people with aphasia may help optimize visual scene selection.
Fission-powered in-core thermoacoustic sensor
Authors: Garrett Steven L. , Smith James A. , Smith Robert W. M. , Heidrich Brenden J. , Heibel Michael D.
Published: April 2016

A thermoacoustic engine is operated within the core of a nuclear reactor to acoustically telemeter coolant temperature (frequency-encoded) and reactor power level (amplitude-encoded) outside the reactor, thus providing the values of these important parameters without external electrical power or wiring. We present data from two hydrophones in the coolant (far from the core) and an accelerometer attached to a structure outside the reactor. These signals have been detected even in the presence of substantial background noise generated by the reactor's fluid pumps.
Design principles for high–pressure force fields: Aqueous TMAO solutions from ambient to kilobar pressures
Authors: Hölzl Christoph , Kibies Patrick , Imoto Sho , Frach Roland , Suladze Saba , Winter Roland , Marx Dominik , Horinek Dominik , Kast Stefan M.
Published: April 2016

Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures – while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute’s response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.
Effect of metal-to-metal interface states on the electric-field modified magnetic anisotropy in MgO/Fe/non-magnetic metal
Authors: Guan X. W. , Cheng X. M. , Huang T. , Wang S. , Xue K. H. , Miao X. S.
Published: April 2016

The impact of metal-to-metal interface on electric-field modified magnetic anisotropy in MgO/Fe/non-magnetic metal (Ta, Pt, Au) is revealed by density functional calculations. We demonstrate that the contribution from the metal-to-metal interface can be strong enough to dominate the electric field effect on magnetic anisotropy of Fe/MgO-based films, and the strain could also effectively tune the electric field effect. By analyzing the interface states by density of states and band structures, the dependence of the magnetoelectric effect on metal-to-metal interface is elucidated. These results are of considerable interest in the area of electric field controlled magnetic anisotropy and switching.
A method of measuring dynamic strain under electromagnetic forming conditions
Authors: Chen Jinling , Xi Xuekui , Wang Sijun , Lu Jun , Guo Chenglong , Wang Wenquan , Liu Enke , Wang Wenhong , Liu Lin , Wu Guangheng
Published: April 2016

Dynamic strain measurement is rather important for the characterization of mechanical behaviors in electromagnetic forming process, but it has been hindered by high strain rate and serious electromagnetic interference for years. In this work, a simple and effective strain measuring technique for physical and mechanical behavior studies in the electromagnetic forming process has been developed. High resolution (∼5 ppm) of strain curves of a budging aluminum tube in pulsed electromagnetic field has been successfully measured using this technique. The measured strain rate is about 105 s−1, which depends on the discharging conditions, nearly one order of magnitude of higher than that under conventional split Hopkins pressure bar loading conditions (∼104 s−1). It has been found that the dynamic fracture toughness of an aluminum alloy is significantly enhanced during the electromagnetic forming, which explains why the formability is much larger under electromagnetic forging conditions in comparison with conventional forging processes.
Highly sensitive simple homodyne phase detector for ultrasonic pulse-echo measurements
Authors: Grossmann John , Suslov Alexey , Yong Grace , Boatner Lynn A. , Svitelskiy Oleksiy
Published: April 2016

We have designed and built a modern versatile research-grade instrument for ultrasound pulse-echo probing of the elastic properties of a wide range of materials under laboratory conditions. The heart of the instrument lies in an AD8302 microchip: a gain and phase detector from Analog Devices, Inc. To construct the device, we have implemented a schematic that utilizes the homodyne principle for signal processing instead of the traditional superheterodyne approach. This design allows one to measure phase shifts with high precision and linearity over the entire range of 0°–360°. The system is simple in construction and usage; it makes ultrasound measurements easily accessible to a broad range of researchers. It was tested by measuring the temperature dependence of the ultrasound speed and attenuation in a KTa0.92Nb0.08O3 (KTN) single crystal at a frequency of ∼40 MHz. The tests were performed in the vicinity of the ferroelectric transitions where the large variations of the speed and attenuation demand a detector with outstanding characteristics. The described detector has a wide dynamic range and allows for measuring in a single run over the whole temperature range of the ferroelectric transitions, rather than just in limited intervals available previously. Moreover, due to the wide dynamic range of the gain measurements and high sensitivity this instrument was able to reveal previously unresolvable features associated with the development of the ferroelectric transitions of KTN crystals.
A new regime of Pauli-spin blockade
Authors: Perron Justin K. , Stewart M. D. , Zimmerman Neil M.
Published: April 2016

Pauli-spin blockade (PSB) is a transport phenomenon in double quantum dots that allows for a type of spin to charge conversion often used to probe fundamental physics such as spin relaxation and singlet-triplet coupling. In this paper, we theoretically explore Pauli-spin blockade as a function of magnetic field B applied parallel to the substrate. In the well-studied low magnetic field regime, where PSB occurs in the forward (1, 1) → (0, 2) tunneling direction, we highlight some aspects of PSB that are not discussed in detail in existing literature, including the change in size of both bias triangles measured in the forward and reverse biasing directions as a function of B. At higher fields, we predict a crossover to “reverse PSB” in which current is blockaded in the reverse direction due to the occupation of a spin singlet as opposed to the traditional triplet blockade that occurs at low fields. The onset of reverse PSB coincides with the development of a tail like feature in the measured bias triangles and occurs when the Zeeman energy of the polarized triplet equals the exchange energy in the (0, 2) charge configuration. In Si quantum dots, these fields are experimentally accessible; thus, this work suggests a way to observe a crossover in magnetic field to qualitatively different behavior.
Stochastic resonance during a polymer translocation process
Authors: Mondal Debasish , Muthukumar M.
Published: April 2016

We have studied the occurrence of stochastic resonance when a flexible polymer chain undergoes a single-file translocation through a nano-pore separating two spherical cavities, under a time-periodic external driving force. The translocation of the chain is controlled by a free energy barrier determined by chain length, pore length, pore-polymer interaction, and confinement inside the donor and receiver cavities. The external driving force is characterized by a frequency and amplitude. By combining the Fokker-Planck formalism for polymer translocation and a two-state model for stochastic resonance, we have derived analytical formulas for criteria for emergence of stochastic resonance during polymer translocation. We show that no stochastic resonance is possible if the free energy barrier for polymer translocation is purely entropic in nature. The polymer chain exhibits stochastic resonance only in the presence of an energy threshold in terms of polymer-pore interactions. Once stochastic resonance is feasible, the chain entropy controls the optimal synchronization conditions significantly.
Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural
Authors: Jones D. B. , da Costa R. F. , Varella M. T. do N. , Bettega M. H. F. , Lima M. A. P. , Blanco F. , García G. , Brunger M. J.
Published: April 2016

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.
Novel linear analysis for a gyrotron oscillator based on a spectral approach
Authors: Genoud J. , Tran T. M. , Alberti S. , Braunmueller F. , Hogge J.-Ph. , Tran M. Q. , Guss W. C. , Temkin R. J.
Published: April 2016

With the aim of gaining a better physical insight into linear regimes in gyrotrons, a new linear model was developed. This model is based on a spectral approach for solving the self-consistent system of equations describing the wave-particle interaction in the cavity of a gyrotron oscillator. Taking into account the wall-losses self-consistently and including the main system inhomogeneities in the cavity geometry and in the magnetic field, the model is appropriate to consider real system parameters. The main advantage of the spectral approach, compared with a time-dependent approach, is the possibility to describe all of the stable and unstable modes, respectively, with negative and positive growth rates. This permits to reveal the existence of a new set of eigenmodes, in addition to the usual eigenmodes issued from cold-cavity modes. The proposed model can be used for studying other instabilities such as, for instance, backward waves potentially excited in gyrotron beam tunnels.
Examination of ionic wind and cathode sheath effects in a E-field premixed flame with ion density measurements
Authors: Jacobs Stewart V. , Xu Kunning G.
Published: April 2016

The effect of the ionic wind on a premixed methane-air flame under a DC electric field is studied via mapping of the ion density with Langmuir probes. Ion densities were observed to increase near the burner with increasing electrode voltage up to 6 kV. Past this electrode supply voltage, ion densities ceased increasing and began to decline in some locations within the premixed flame. The increased ion density is caused by an increase in ionic wind force and cathode sheath thickness. The plateau in density is due to the cathode sheath fully encompassing the flame front which is the ion source, thereby collecting all ions in the flame. The spatial density data support the ionic wind hypothesis and provide further explanation of its limits based on the plasma sheath.
Quantitative comparison of electron temperature fluctuations to nonlinear gyrokinetic simulations in C-Mod Ohmic L-mode discharges
Authors: Sung C. , White A. E. , Mikkelsen D. R. , Greenwald M. , Holland C. , Howard N. T. , Churchill R. , Theiler C. ,   Alcator C-Mod Team
Published: April 2016

Long wavelength turbulent electron temperature fluctuations (kyρs < 0.3) are measured in the outer core region (r/a > 0.8) of Ohmic L-mode plasmas at Alcator C-Mod [E. S. Marmar et al., Nucl. Fusion 49, 104014 (2009)] with a correlation electron cyclotron emission diagnostic. The relative amplitude and frequency spectrum of the fluctuations are compared quantitatively with nonlinear gyrokinetic simulations using the GYRO code [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] in two different confinement regimes: linear Ohmic confinement (LOC) regime and saturated Ohmic confinement (SOC) regime. When comparing experiment with nonlinear simulations, it is found that local, electrostatic ion-scale simulations (kyρs ≲ 1.7) performed at r/a ∼ 0.85 reproduce the experimental ion heat flux levels, electron temperature fluctuation levels, and frequency spectra within experimental error bars. In contrast, the electron heat flux is robustly under-predicted and cannot be recovered by using scans of the simulation inputs within error bars or by using global simulations. If both the ion heat flux and the measured temperature fluctuations are attributed predominantly to long-wavelength turbulence, then under-prediction of electron heat flux strongly suggests that electron scale turbulence is important for transport in C-Mod Ohmic L-mode discharges. In addition, no evidence is found from linear or nonlinear simulations for a clear transition from trapped electron mode to ion temperature gradient turbulence across the LOC/SOC transition, and also there is no evidence in these Ohmic L-mode plasmas of the “Transport Shortfall” [C. Holland et al., Phys. Plasmas 16, 052301 (2009)].
Effective photon mass and exact translating quantum relativistic structures
Authors: Haas Fernando , Manrique Marcos Antonio Albarracin
Published: April 2016

Using a variation of the celebrated Volkov solution, the Klein-Gordon equation for a charged particle is reduced to a set of ordinary differential equations, exactly solvable in specific cases. The new quantum relativistic structures can reveal a localization in the radial direction perpendicular to the wave packet propagation, thanks to a non-vanishing scalar potential. The external electromagnetic field, the particle current density, and the charge density are determined. The stability analysis of the solutions is performed by means of numerical simulations. The results are useful for the description of a charged quantum test particle in the relativistic regime, provided spin effects are not decisive.
Continuous development of current sheets near and away from magnetic nulls
Authors: Kumar Sanjay , Bhattacharyya R.
Published: April 2016

The presented computations compare the strength of current sheets which develop near and away from the magnetic nulls. To ensure the spontaneous generation of current sheets, the computations are performed congruently with Parker's magnetostatic theorem. The simulations evince current sheets near two dimensional and three dimensional magnetic nulls as well as away from them. An important finding of this work is in the demonstration of comparative scaling of peak current density with numerical resolution, for these different types of current sheets. The results document current sheets near two dimensional magnetic nulls to have larger strength while exhibiting a stronger scaling than the current sheets close to three dimensional magnetic nulls or away from any magnetic null. The comparative scaling points to a scenario where the magnetic topology near a developing current sheet is important for energetics of the subsequent reconnection.
Dispersive Alfvén waves in a plasma with anisotropic superthermal particles
Authors: Liu Y. , Wang Y. F. , Hu T. P.
Published: April 2016

The dispersion of dispersive Alfvén wave in a low β plasma with anisotropic superthermal particles modeled by a bi-nonextensive distribution is derived from a kinetic way. The effect of anisotropic temperature on inertial Alfvén wave is so small that it is negligible. However, it will play an important role on the property of kinetic Alfvén wave (KAW). The numerical results reveal that the presence of superthermal electrons in the small wavenumber limit will lead the damping rate of the KAW bigger than the one with Maxwellian distribution. Whereas, the damping rate of KAW in the large wavenumber limit will decrease with the presence of superthermal electrons. When the effect of electron anisotropic temperature overwhelms the effect of finite ion gyroradius in the small wavenumber regime, the damping rate of KAW grows with the presence of electron temperature anisotropy. On the other hand, when the effects of finite ion gyroradius play a dominant role in the large wavenumber regime, the damping rate of KAW increases with the effective perpendicular and parallel electron temperatures.
Near monochromatic 20 Me V proton acceleration using fs laser irradiating Au foils in target normal sheath acceleration regime
Authors: Torrisi L. , Cutroneo M. , Ceccio G. , Cannavò A. , Batani D. , Boutoux G. , Jakubowska K. , Ducret J. E.
Published: April 2016

A 200 mJ laser pulse energy, 39 fs-pulse duration, 10 μm focal spot, p-polarized radiation has been employed to irradiate thin Au foils to produce proton acceleration in the forward direction. Gold foils were employed to produce high density relativistic electrons emission in the forward direction to generate a high electric field driving the ion acceleration. Measurements were performed by changing the focal position in respect of the target surface. Proton acceleration was monitored using fast SiC detectors in time-of-flight configuration. A high proton energy, up to about 20 Me V, with a narrow energy distribution, was obtained in particular conditions depending on the laser parameters, the irradiation conditions, and a target optimization.
High illumination uniformity scheme with 32 beams configuration for direct-drive inertial confinement fusion
Authors: Li Li , Gu Chun , Xu Lixin , Zhou Shenlei
Published: April 2016

The self-adapting algorithms are improved to optimize a beam configuration in the direct drive laser fusion system with the solid state lasers. A configuration of 32 laser beams is proposed for achieving a high uniformity illumination, with a root-mean-square deviation at 10−4 level. In our optimization, the parameters such as beam number, beam arrangement, and beam intensity profile are taken into account. The illumination uniformity robustness versus the parameters such as intensity profile deviations, power imbalance, intensity profile noise, the pointing error, and the target position error is also discussed. In this study, the model is assumed a solid-sphere illumination, and refraction effects of incident light on the corona are not considered. Our results may have a potential application in the design of the direct-drive laser fusion of the Shen Guang-II Upgrading facility (SG-II-U, China).
Influence of equilibrium shear flow in the parallel magnetic direction on edge localized mode crash
Authors: Luo Y. , Chen S. Y. , Huang J. , Xiong Y. Y. , Tang C. J.
Published: April 2016

The influence of the parallel shear flow on the evolution of peeling-ballooning (P-B) modes is studied with the BOUT++ four-field code in this paper. The parallel shear flow has different effects in linear simulation and nonlinear simulation. In the linear simulations, the growth rate of edge localized mode (ELM) can be increased by Kelvin-Helmholtz term, which can be caused by the parallel shear flow. In the nonlinear simulations, the results accord with the linear simulations in the linear phase. However, the ELM size is reduced by the parallel shear flow in the beginning of the turbulence phase, which is recognized as the P-B filaments' structure. Then during the turbulence phase, the ELM size is decreased by the shear flow.
Interaction between ions in hot dense plasma via screened Cornell potential
Authors: Ramazanov T. S. , Moldabekov Zh. A. , Gabdullin M. T.
Published: April 2016

Hot dense plasma with non-ideal ions and weakly coupled electrons is studied analytically in the framework of the random phase approximation. It is shown that at some plasma parameters ions interact by a screened Cornell potential. The reduction in the transport coefficients due to the localization of the electron around the ion is predicted. This prediction is confirmed by the molecular dynamics simulation of the one-component ion plasma interacting via the obtained screened Cornell type potential.
Coherent control of the Goos-Hänchen shift via Fano interference
Authors: Liu Shaopeng , Yang Wen-Xing , Zhu Zhonghu
Published: April 2016

A scheme of enhanced Goos-Hänchen (GH) shifts in reflected and transmitted light beams is exploited in a cavity, where an asymmetric double AlGaAs/GaAs quantum well structure with resonant tunneling to a common continuum is employed as the intracavity medium. With the help of Fano-type interference induced by resonant tunneling, the generated GH shifts that contain a negative lateral shift in reflected light beam and a positive lateral shift in transmitted light beam are found to be significantly enhanced. More interestingly, these GH shifts in reflected and transmitted light beams are modulated by means of a control beam and external bias voltage, in which maximum negative shift of 1.86 mm and positive shift of 0.37 mm are achievable.
Memristor and selector devices fabricated from HfO2−xNx
Authors: Murdoch B. J. , McCulloch D. G. , Ganesan R. , McKenzie D. R. , Bilek M. M. M. , Partridge J. G.
Published: April 2016

Monoclinic HfO2−xNx has been incorporated into two-terminal devices exhibiting either memristor or selector operation depending on the controlled inclusion/suppression of mobile oxygen vacancies. In HfO2 memristors containing oxygen vacancies, gradual conductance modulation, short-term plasticity, and long-term potentiation were observed using appropriate voltage-spike stimulation, suggesting suitability for artificial neural networks. Passivation of oxygen vacancies, confirmed by X-ray absorption spectroscopy, was achieved in HfO2−xNx films by the addition of nitrogen during growth. Selector devices formed on these films exhibited threshold switching and current controlled negative differential resistance consistent with thermally driven insulator to metal transitions.
Nitrogen anion doping as a strategy to suppress negative gate-bias illumination instability of ZnSnO thin film transistor
Authors: Li Jun , Fu Yi-Zhou , Huang Chuan-Xin , Zhang Jian-Hua , Jiang Xue-Yin , Zhang Zhi-Lin
Published: April 2016

This work presents a strategy of nitrogen anion doping to suppress negative gate-bias illumination instability. The electrical performance and negative gate-bias illumination stability of the ZnSnON thin film transistors (TFTs) are investigated. Compared with ZnSnO-TFT, ZnSnON-TFT has a 53% decrease in the threshold voltage shift under negative bias illumination stress and electrical performance also progresses obviously. The stability improvement of ZnSnON-TFT is attributed to the reduction in ionized oxygen vacancy defects and the photodesorption of oxygen-related molecules. It suggests that anion doping can provide an effective solution to the adverse tradeoff between field effect mobility and negative bias illumination stability.
The tandem duplicator phenotype as a distinct genomic configuration in cancer
Authors: Menghi Francesca , Inaki Koichiro , Woo XingYi , Kumar Pooja A. , Grzeda Krzysztof R. , Malhotra Ankit , Yadav Vinod , Kim Hyunsoo , Marquez Eladio J. , Ucar Duygu , Shreckengast Phung T. , Wagner Joel P. , MacIntyre George , Murthy Karuturi Krishna R. , Scully Ralph , Keck James , Chuang Jeffrey H. , Liu Edison T.
Published: April 2016

Significance

In this study, we provide the first detailed molecular characterization, to our knowledge, of a distinct cancer genomic configuration, the tandem duplicator phenotype (TDP), that is significantly enriched in the molecularly related triple-negative breast, serous ovarian, and endometrial carcinomas. We show here that TDP represents an oncogenic configuration featuring (
i
) genome-wide disruption of cancer genes, (
ii
) loss of cell cycle control and DNA damage repair, and (
iii
) increased sensitivity to cisplatin chemotherapy both in vitro and in vivo. Therefore, the TDP is a systems strategy to achieve a protumorigenic genomic configuration by altering a large number of oncogenes and tumor suppressors. The TDP arises in a molecular context of joint genomic instability and replicative drive, and is consequently associated with enhanced sensitivity to cisplatin.
Whey protein hydrolysates enhance water absorption in the perfused small intestine of anesthetized rats
Authors: Ito Kentaro , Yamaguchi Makoto , Noma Teruyuki , Yamaji Taketo , Itoh Hiroyuki , Oda Munehiro
Published: April 2016

We evaluated the effect of whey protein hydrolysates (WPH) on the water absorption rate in the small intestine using a rat small intestine perfusion model. The rate was significantly higher with 5 g/L WPH than with 5 g/L soy protein hydrolysates or physiological saline (p < 0.05). WPH dose-dependently increased the water absorption rate in the range of 1.25–10.0 g/L. WPH showed a significantly higher rate than an amino acid mixture whose composition was equal to that of WPH (p < 0.05). The addition of 4-aminomethylbenzoic acid, an inhibitor of PepT1, significantly suppressed WPH’s enhancement of water absorption (p < 0.05). The rate of water absorption was significantly correlated with that of peptides/amino acids absorption in WPH (r = 0.82, p < 0.01). These data suggest that WPH have a high water absorption-promoting effect, to which PepT1 contributes.
Predicting the effects of habitat loss on corsac fox occupancy in Mongolia
Authors: Lkhagvasuren Myagmarjav , Murdoch James D. , Munkhzul Tserendorj , Strong Allan M.
Published: April 2016

Landscape change affects the distribution of wildlife and represents a conservation concern, especially in Asia, which is experiencing rapid development. We examined the impacts of landscape change on corsac foxes in Mongolia. We addressed 2 questions: 1) how do common features of a landscape, such as habitats, topography, and human structures, shape the distribution of the species? and 2) how will the loss of those features affect distribution? We developed an occupancy model based on locations (n = 2,437) collected in Ikh Nart Nature Reserve, then estimated the marginal loss in average occupancy across the landscape when features were removed. The model with the most support indicated that occupancy was best described by the additive combination of open plain, tall grassland, and shrubland habitats. Average occupancy across the reserve was 22% under current conditions. Simulations involving the removal of each habitat resulted in a marginal loss of 12%, 35%, and 49% in average occupancy, respectively. The loss of all 3 habitats, as expected under climate change projections, will probably make the landscape unsuitable. The results provide the first model of corsac fox occupancy, which can be used to examine distribution and impacts of change in other parts of the species’ range. They also suggest that managers should plan conservation activities to allow corsac fox distribution to shift northward as the region becomes warmer and drier and vegetation communities change.