bluuebunny/crossref_metadata_2025 huggingface dataset:
The use of a TLR2 agonist‐based adjuvant for enhancing effector and memory CD8 T‐cell responses
Authors: Chua Brendon Y , Olson Matthew R , Bedoui Sammy , Sekiya Toshiki , Wong Chinn Y , Turner Stephen J , Jackson David C
Published: January 2014

We have previously shown that the immunogenicity of protein antigens can be significantly enhanced if electrostatically associated with the Toll‐like receptor‐2 agonist‐based lipopeptide R4Pam2Cys. The precise mechanisms and effectiveness of the cytotoxic T‐lymphocyte (CTL)‐mediated response facilitated by this agonist, however, have not been studied. Here we show that priming by dendritic cells (DCs) in the draining lymph nodes of animals vaccinated with antigen delivered using R4Pam2Cys results in significantly improved T‐cell proliferation and induces their differentiation into polyfunctional effector CTLs characterised by granzyme B expression and the ability to secrete interferon‐γ, interleukin‐2 and tumor necrosis factor‐α 7 days after vaccination. After 30 days, frequencies of antigen‐specific CD62lowCD127high (effector memory), CD62highCD127high (central memory) and CD43lowCD27high CD8+ T cells, a phenotype associated with strong recall responses against respiratory infections, are also increased compared with responses obtained with antigens formulated in the adjuvants Alum (alhydrogel) and CFA (complete Freund's adjuvant). The phenotypic changes observed in these mice vaccinated using R4Pam2Cys further correlated with their ability to recall specific T cells into the lung to mediate the reduction of pulmonary viral titres following challenge with a chimeric influenza virus containing the KbOVA257–264 epitope compared with animals vaccinated using Alum or CFA. The findings from this study not only demonstrate that better T‐cell responses can be elicited using R4Pam2Cys compared with classically utilised adjuvants but also highlight the potential effectiveness of this lipopeptide‐based adjuvant particularly against viral infections that require resolution through cell‐mediated immunity.
The temporospatial control of Tfh cells
Authors: Yu Di , Linterman Michelle
Published: January 2014

The January 2014 issue contains a Special Feature on The Temporospatial Control of Tfh Cells. The reviews featured bring together an enormous amount of insight into Tfh biology: they demonstrate that we have a good understanding of Tfh differentiation and function, but that there is still more to be learned about the intriguing population of helper T cells specialised to help B cells. Furthermore, they outline how important this subset is in both health and disease, and demonstrate that furthering our knowledge of this subset will have implications for improving the efficacy of vaccination, the control of infection, the treatment of both autoimmunity and immunodeficiency and even understanding the outcome of a number of different types of cancer. Immunology and Cell Biology would like to thank the coordinators of this Special Feature – Di Yu and Michelle Linterman – for their planning and input. Further background information on this important topic is available through the accompanying web focus which links to related articles from across Nature Publishing Group.
CCR6 and CCL20: emerging players in the pathogenesis of rheumatoid arthritis
Authors: Lee Adrian YS , Körner Heinrich
Published: January 2014

The therapeutic targeting of pro‐inflammatory TNF with neutralising biological anti‐TNF agents, often in combination with other disease‐modifying anti‐rheumatic drugs, such as the purine synthesis inhibitor methotrexate has been the first major break‐through in the treatment of chronic inflammatory diseases in decades. There are however, side effects and disadvantages of these treatments, such as general immunosuppression as well as therapy resistance in a large proportion of patients. This evokes the wish for other, more specialised forms of treatments. The targeting of chemokines and their receptors to disrupt cell movement specifically has been seen as a promising avenue of therapy for a considerable time. We will discuss one particular chemokine and its receptor, the C‐C chemokine ligand CCL20 and the C‐C chemokine receptor CCR6, and summarise its genetic and biological role in rheumatoid arthritis (RA). CCR6 has been associated with RA in genome‐wide association studies and has been shown to be an interesting candidate for a therapeutic approach, considering its and CCL20's expression patterns within the tissue as well as the immune system.
Orthogonally modulated molecular transport junctions for resettable electronic logic gates
Authors: Meng Fanben , Hervault Yves-Marie , Shao Qi , Hu Benhui , Norel Lucie , Rigaut Stéphane , Chen Xiaodong
Published: January 2014

Individual molecules have been demonstrated to exhibit promising applications as functional components in the fabrication of computing nanocircuits. Based on their advantage in chemical tailorability, many molecular devices with advanced electronic functions have been developed, which can be further modulated by the introduction of external stimuli. Here, orthogonally modulated molecular transport junctions are achieved via chemically fabricated nanogaps functionalized with dithienylethene units bearing organometallic ruthenium fragments. The addressable and stepwise control of molecular isomerization can be repeatedly and reversibly completed with a judicious use of the orthogonal optical and electrochemical stimuli to reach the controllable switching of conductivity between two distinct states. These photo-/electro-cooperative nanodevices can be applied as resettable electronic logic gates for Boolean computing, such as a two-input OR and a three-input AND-OR. The proof-of-concept of such logic gates demonstrates the possibility to develop multifunctional molecular devices by rational chemical design.
Innexin gap junctions in nerve cells coordinate spontaneous contractile behavior in Hydra polyps
Authors: Takaku Yasuharu , Hwang Jung Shan , Wolf Alexander , Böttger Angelika , Shimizu Hiroshi , David Charles N. , Gojobori Takashi
Published: January 2014

Nerve cells and spontaneous coordinated behavior first appeared near the base of animal evolution in the common ancestor of cnidarians and bilaterians. Experiments on the cnidarian Hydra have demonstrated that nerve cells are essential for this behavior, although nerve cells in Hydra are organized in a diffuse network and do not form ganglia. Here we show that the gap junction protein innexin-2 is expressed in a small group of nerve cells in the lower body column of Hydra and that an anti-innexin-2 antibody binds to gap junctions in the same region. Treatment of live animals with innexin-2 antibody eliminates gap junction staining and reduces spontaneous body column contractions. We conclude that a small subset of nerve cells, connected by gap junctions and capable of synchronous firing, act as a pacemaker to coordinate the contraction of the body column in the absence of ganglia.
Dispersal-induced destabilization of metapopulations and oscillatory Turing patterns in ecological networks
Authors: Hata Shigefumi , Nakao Hiroya , Mikhailov Alexander S.
Published: January 2014

As shown by Alan Turing in 1952, differential diffusion may destabilize uniform distributions of reacting species and lead to emergence of patterns. While stationary Turing patterns are broadly known, the oscillatory instability, leading to traveling waves in continuous media and sometimes called the wave bifurcation, remains less investigated. Here, we extend the original analysis by Turing to networks and apply it to ecological metapopulations with dispersal connections between habitats. Remarkably, the oscillatory Turing instability does not lead to wave patterns in networks, but to spontaneous development of heterogeneous oscillations and possible extinction of species. We find such oscillatory instabilities for all possible food webs with three predator or prey species, under various assumptions about the mobility of individual species and nonlinear interactions between them. Hence, the oscillatory Turing instability should be generic and must play a fundamental role in metapopulation dynamics, providing a common mechanism for dispersal-induced destabilization of ecosystems.
Rapid profiling of enteric coated drug delivery spheres via Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS)
Authors: Fitzpatrick D. , Evans-Hurson R. , Fu Y. , Burke T. , Krüse J. , Vos B. , McSweeney S. G. , Casaubieilh P. , Keating J. J.
Published: January 2014

There is an increased trend towards the use of drug and enteric coated sugar spheres for controlled oral delivery of active pharmaceutical ingredients (API).
Development of a bio-analytical strategy for characterization of vaccine particles combining SEC and nanoES GEMMA
Authors: Havlik Marlene , Marchetti-Deschmann Martina , Friedbacher Gernot , Messner Paul , Winkler Wolfgang , Perez-Burgos Laura , Tauer Christa , Allmaier Günter
Published: January 2014

In order to characterize vaccine-nanoparticles during production and in the final formulation we developed a strategy combining SEC and nano-electrospray GEMMA (nanoparticle number concentration-based ion mobility device).
Human plasma stability during handling and storage: impact on NMR metabolomics
Authors: Pinto Joana , Domingues M. Rosário M. , Galhano Eulália , Pita Cristina , Almeida Maria do Céu , Carreira Isabel M. , Gil Ana M.
Published: January 2014

The stability of human plasma composition was investigated by NMR, considering different collection tubes, time at room temperature (RT), short- and long-term storage conditions and up to 5 consecutive freeze–thaw cycles.
Application of near-infrared spectroscopy for monitoring the formulation process of low-dose tablets
Authors: Peng Feng , Wang Wan , Luo Wei , Liu Yanxin , Li Hui
Published: January 2014

NIR spectroscopy was used to monitor multiple parameters simultaneously and satisfactory validation results were obtained.
Induction of an electrochemiluminescence sensor for DNA detection of Clostridium perfringens based on rolling circle amplification
Authors: Jiang Dongneng , Liu Fei , Liu Chang , Liu Linlin , Li Yi , Pu Xiaoyun
Published: January 2014

Induction of an electrochemiluminescence sensor for DNA detection ofClostridium perfringensbased on rolling circle amplification (RCA).
Template-free multicomponent coordination-driven self-assembly of Pd(ii)/Pt(ii) molecular cages
Authors: Mukherjee Sandip , Mukherjee Partha Sarathi
Published: January 2014

This article summarizes the recent developments in the construction of multicomponent molecular hollowed-out cages through the metal–ligand coordination-driven self-assembly process, with a focus on the decreasing relevance of the use of templates.
Ruthenium-catalyzed ortho-arylation of acetanilides with aromatic boronic acids: an easy route to prepare phenanthridines and carbazoles
Authors: Chinnagolla Ravi Kiran , Jeganmohan Masilamani
Published: January 2014

A regioselective ruthenium-catalyzed ortho-arylation of acetanilides with aromatic boronic acids is described. Later, ortho-arylated acetanilides were converted into phenanthridine and carbazole derivatives.
Zn-doped In2O3 hollow spheres: mild solution reaction synthesis and enhanced Cl2 sensing performance
Authors: Li Pei , Fan Huiqing , Cai Yu , Xu Mengmeng
Published: January 2014

Microstructures and Cl2-sensing performances of Zn-doped In2O3 hollow spheres.
The substituent effect on benzene dications
Authors: Palusiak Marcin , Domagała Małgorzata , Dominikowska Justyna , Bickelhaupt F. Matthias
Published: January 2014

It was shown that the substituent effect in the dicationic benzene ring, which is a 4nπ-electron system, can be numerically quantified and then further interpreted.
Synthesis of cyclic carbonates from CO2 and epoxides using ionic liquids and related catalysts including choline chloride–metal halide mixtures
Authors: He Qing , O'Brien Jeremy W. , Kitselman Kayla A. , Tompkins Lindsay E. , Curtis Gregory C. T. , Kerton Francesca M.
Published: January 2014

In this mini-review, progress made in the use of ionic liquid catalysts and related systems for cycloaddition reactions of carbon dioxide with epoxides is described with the primary focus on results from the past eight years.
DFT study on the reaction mechanism of the ring closing enyne metathesis (RCEYM) catalyzed by molybdenum alkylidene complexes
Authors: Solans-Monfort Xavier
Published: January 2014

DFT calculations show that the RCEYM reaction catalyzed by Mo-based catalysts proceeds preferentially through an yne-then-ene mechanism and that the endo-/exo- selectivity mainly depends on sterics.
Highly efficient separation of rare earths from nickel and cobalt by solvent extraction with the ionic liquid trihexyl(tetradecyl)phosphonium nitrate: a process relevant to the recycling of rare earths from permanent magnets and nickel metal hydride batteries
Authors: Vander Hoogerstraete Tom , Binnemans Koen
Published: January 2014

The undiluted ionic liquid trihexyl(tetradecyl)phosphonium nitrate was used for cobalt–samarium and nickel–lanthanum separations by solvent extraction.
Effect of preparation methods on the performance of Co/Al2O3 catalysts for dry reforming of methane
Authors: Ewbank Jessica L. , Kovarik Libor , Kenvin Christian C. , Sievers Carsten
Published: January 2014

Co/Al2O3 catalysts were synthesized by dry impregnation and controlled adsorption. The effect of catalyst preparation methods on their performance in methane dry reforming was studied.
Matrices from vegetable oils, cashew nut shell liquid, and other relevant systems for biocomposite applications
Authors: Quirino Rafael L. , Garrison Thomas F. , Kessler Michael R.
Published: January 2014

This review focuses on the progress made over the last decade, in the development of bio-based matrices for biocomposite applications.
A sustainable biotechnological process for the efficient synthesis of kojibiose
Authors: Díez-Municio Marina , Montilla Antonia , Moreno F. Javier , Herrero Miguel
Published: January 2014

This work reports the optimization of a cost-effective and scalable process for the enzymatic synthesis of kojibiose (2-O-α-d-glucopyranosyl-α-d-glucose) from readily available and low-cost substrates such as sucrose and lactose.
tert-Butyl hydroperoxide (TBHP)-mediated oxidative self-coupling of amines to imines over a α-MnO2 catalyst
Authors: Zhang Zhe , Wang Feng , Wang Min , Xu Shutao , Chen Haijun , Zhang Chaofeng , Xu Jie
Published: January 2014

A methodology for the direct synthesis of imines from amines via a facile α-MnO2 catalyzed-procedure at room temperature with TBHP as an oxidant was described. The catalysis is suitability for 13 aromatic and aliphatic amines, and it is heterogeneous, recyclable and reusable.
Direct conversion of chitin into a N-containing furan derivative
Authors: Chen Xi , Chew Shu Ling , Kerton Francesca M. , Yan Ning
Published: January 2014

One pot conversion of chitin into 3A5AF opens up a new avenue for renewable, value added N-containing chemicals.
Non-chromatographic speciation of inorganic arsenic by atomic fluorescence spectrometry with flow injection hydride generation with a tetrahydroborate-form anion-exchanger
Authors: Wang Nan , Tyson Julian
Published: January 2014

Two reaction conditions, with different HCl andl-cysteine concentrations, allow determination of both species in real tap, well, pond, and seawater samples down to 15 ng L−1.
Synthesis and characterization of a new aluminophosphate with a Al3P6O249− three-dimensional framework
Authors: Wang Ying , Pan Shilie , Han Shujuan , Dong Lingyun , Zhang Min , Wu Kui
Published: January 2014

A novel metal aluminophosphate, K6Na3Al3P6O24, exhibits a unique Al3P6O249− three-dimensional framework with an Al/P ratio of 1/2.
Transition from direct to Fowler–Nordheim tunneling in chemically reduced graphene oxide film
Authors: Pandey Srikrishna , Biswas Chandan , Ghosh Titisa , Bae Jung Jun , Rai Padmnabh , Kim Gil-Ho , Thomas K. J. , Lee Young Hee , Nikolaev Pavel , Arepalli Sivaram
Published: January 2014

Transition from direct to F–N tunnelling is observed in a reduced graphene oxide film under a wide range of applied potentials.
Controllable synthesis of SnO2@C yolk–shell nanospheres as a high-performance anode material for lithium ion batteries
Authors: Wang Jinxiu , Li Wei , Wang Fei , Xia Yongyao , Asiri Abdullah M. , Zhao Dongyuan
Published: January 2014

Uniform SnO2@C yolk–shell nanospheres as high-performance anode materials for lithium ion batteries.
Copper-catalyzed oxidative cascade coupling of N-alkyl-N-phenylacrylamides with aryl aldehydes
Authors: Gong Weiwei , Xu Lei , Ji Tao , Xie Ping , Qi Xueyong , Pittman Charles U. , Zhou Aihua
Published: January 2014

An oxidative cascade coupling reaction between N-alkyl-N-phenylacrylamides and aryl aldehydes using CuCl2/TBHP (tert-butyl hydroperoxide) as a catalyst and oxidant was developed.
Supramolecular analyte recognition: experiment and theory interplay
Authors: Kaur Paramjit , Singh Kamaljit
Published: January 2014

Synergy of experimental and theoretical tools has made significant impact in the assessment of supramolecular recognition of analytes of relevance to biology and the environment.
Engineered fluorescence tags for in vivo protein labelling
Authors: Wang Zhipeng , Ding Xiaozhe , Li Sijian , Shi Jing , Li Yiming
Published: January 2014

In vivoprotein labelling with a peptide tag–fluorescent probe system is an important chemical biology strategy for studying protein distribution, interaction and function.
Metal catalyst free one-pot synthesis of 2-arylbenzimidazoles from α-aroylketene dithioacetals
Authors: Dhanalakshmi Pandi , Thimmarayaperumal Solaimalai , Shanmugam Sivakumar
Published: January 2014

An efficient green synthetic approach has been developed towards the synthesis of 2-aryl substituted benzimidazoles4from α-aroylketene dithioacetals (AKDTAs)1and phenylenediamine (OPD)2.
Facile and economical mass production of graphene dispersions and flakes
Authors: Mao Min , Chen Shuzhen , He Ping , Zhang Hailin , Liu Hongtao
Published: January 2014

A facile and economical strategy for the bulk production of aqueous graphene dispersions and high-quality few-layer graphene flakes via a simple ball milling process assisted with non-ionic industrial surfactant.
Ultrathin Cu7S4nanosheets-constructed hierarchical hollow cubic cages: one-step synthesis based on Kirkendall effect and catalysis property
Authors: Jiang Yingchang , Zhang Shudong , Ji Qi , Zhang Jian , Zhang Zhongping , Wang Zhenyang
Published: January 2014

Ultrathin Cu7S4nanosheets-constructed nanocages were synthesized in one step based on the Kirkendall effect, which could effectively catalyze the “clock reaction” of methylene blue.
Versatile superhydrophobic and photocatalytic films generated from TiO2–SiO2@PDMS and their applications on fabrics
Authors: Deng Zheng-Yan , Wang Wei , Mao Li-Hua , Wang Cai-Feng , Chen Su
Published: January 2014

We report a facile and practical approach to fabricate versatile superhydrophobic and photocatalytic films from TiO2–SiO2@PDMS hybrids. The as-prepared hybrids can be applied to functional superhydrophobic textiles, treatment of dye waste water and water-repellent coatings.
Electrochemical nucleation and growth of Pd/PdCo core–shell nanoparticles with enhanced activity and durability as fuel cell catalyst
Authors: Rezaei Milad , Tabaian Seyed Hadi , Haghshenas Davoud Fatmehsari
Published: January 2014

Cyclic voltammetry curves of Pd NPs and Pd/PdCo core–shell NPs in 0.5 M HCOOH + 0.5 M H2SO4.
Dual endogenous stimuli-responsive polyplex micelles as smart two-step delivery nanocarriers for deep tumor tissue penetration and combating drug resistance of cisplatin
Authors: Li Junjie , Han Yu , Chen Qixian , Shi Hongdong , ur Rehman Saif , Siddiq Mohammad , Ge Zhishen , Liu Shiyong
Published: January 2014

Polyplex micelles were constructed for deep tumor tissue penetration and combating drug resistance via endogenous stimuli-responsive two-step release profiles.
Hemocompatibility comparison of biomedical grade polymers using rabbit thrombogenicity model for preparing nonthrombogenic nitric oxide releasing surfaces
Authors: Handa Hitesh , Major Terry C. , Brisbois Elizabeth J. , Amoako Kagya A. , Meyerhoff Mark E. , Bartlett Robert H.
Published: January 2014

In a polymer comparison, E2As was found to have superior hemocompatibility and then was used to prepare nitric oxide (NOrel) surfaces and tested in a 4 h rabbit model.
Cross-linking of protein scaffolds for therapeutic applications: PCL nanofibers delivering riboflavin for protein cross-linking
Authors: Sridhar Radhakrishnan , Madhaiyan Kalaipriya , Sundarrajan Subramanian , Góra Aleksander , Venugopal Jayarama Reddy , Ramakrishna Seeram
Published: January 2014

We propose a new concept of cross-linking natural protein nanofibers using riboflavin following UV treatment, and demonstrate it with gelatin cross-linking in nanofibers, film and solution.
Oxadiazole based bipolar host materials employing planarized triarylamine donors for RGB PHOLEDs with low efficiency roll-off
Authors: Kautny Paul , Lumpi Daniel , Wang Yanping , Tissot Antoine , Bintinger Johannes , Horkel Ernst , Stöger Berthold , Hametner Christian , Hagemann Hans , Ma Dongge , Fröhlich Johannes
Published: January 2014

The impact of planarization of triarylamine donors on thermal, photo-physical and electro-chemical properties of novel materials is examined with regard to PHOLED applications.
Phosphorescent O2sensors based on polyolefin fabric materials
Authors: Kelly Caroline A. , Toncelli Claudio , Kerry Joe P. , Papkovsky Dmitri B.
Published: January 2014

New oxygen sensors based on non-woven polypropylene membranes with grafted and ungrafted monofibres impregnated with a phosphorescent dye were created and evaluated.
The ability of TRIM3 to induce growth arrest depends on RING-dependent E3 ligase activity
Authors: Raheja Radhika , Liu Yuhui , Hukkelhoven Ellen , Yeh Nancy , Koff Andrew
Published: January 2014

Mutation of the TRIM (tripartite motif)-NHL family members brat and mei-P26 perturb the differentiation of transit-amplifying progenitor cells resulting in tumour-like phenotypes. The NHL (named after the NCL1, HT2A and LIN41 repeat) domain is essential for their growth suppressive activity, and they can induce cell-cycle exit in a RING-independent manner. TRIM3 is the only bona fide tumour suppressor in the mammalian TRIM-NHL subfamily and similar to the other members of this family, its ability to inhibit cell proliferation depends on the NHL domain. However, whether the RING domain was required for TRIM3-dependent cell-cycle exit had not been investigated. In the present study, we establish that the RING domain is required for TRIM3-induced growth suppression. Furthermore, we show that this domain is necessary to promote ubiquitination of p21 in a reconstituted in vitro system where UbcH5a is the preferred E2. Thus the ability of TRIM3 to suppress growth is associated with its ability to ubiquitinate proteins.
Strategic analysis of stakeholder preferences regarding the design of ITS‐based road safety measures
Authors: De Brucker Klaas , Macharis Cathy , Wiethoff Marion , Marchau Vincent
Published: January 2014

In this study, a multi‐stakeholder/multi‐actor multi‐criteria analysis (MAMCA) is applied to obtain a selection and preliminary ranking for a number of alternative ways to design innovative ITS‐based tools that have the potential to improve road safety by creating a more forgiving road (FOR) and a more self‐explaining road (SER) environment. The aim of this MCA is to allow various stakeholders with an interest in improving road safety (in particular public policymakers, but also users and manufacturers), to assess alternative designs for future FOR and SER environments. For each of these stakeholders a separate MCA is carried out taking into account their specific objectives. By analysing the differences in preferences among stakeholders and using the highest expected ‘value‐added’ from the community of stakeholders in its entirety on various FOR and SER environments, it has been possible to uncover information on the chances of successful implementation.
Implementation of a stepped down frequency eight switches matrix converter suitable for microturbine generation
Authors: Khoun Jahan Hossein , Banaei Mohamad Reza
Published: January 2014

In this study, a three‐phase to three‐phase matrix converter with eight switches in each phase is presented. In addition, a simple switching strategy is used to control switches based on the comparison of a reference output voltage value with 12 voltage values obtained from input voltage. One advantage of the simple switching approach is that it is suitable to step down input voltage frequency. So, it is applicable to interface microturbine generation and load. This converter can boost input voltage amplitude with variable reduced frequency with respect to conventional matrix converter using a simple switching technique. Other advantages of the suggested converter is that it is possible to obtain a voltage with low total harmonic distortion by applying the stated switching method as compared to conventional matrix converter. Simulation and experimental results are shown to validate the capability of the suggested converter in the boosting of input voltage at a variable frequency.
Wideband‐scaled Radon‐Fourier transform for high‐speed radar target detection
Authors: Qian Li‐Chang , Xu Jia , Xia Xiang‐Gen , Sun Wen‐Feng , Long Teng , Peng Ying‐Ning
Published: January 2014

High target speed, long pulse duration or wide signal bandwidth may cause noticeable scale effect on radar echoes, for which the conventional narrowband matched filter may introduce an obvious signal‐to‐noise ratio (SNR) loss for target detection. To obtain the ideal SNR gain in the above scenarios, a novel long‐time coherent integration method has been proposed, namely wideband‐scaled Radon‐Fourier transform (WSRFT). The proposed WSRFT can compensate the scale effect not only on the single pulse but also among the multiple pulses in a long coherent integration time. Furthermore, the performance comparison between the proposed WSRFT and the existing Radon‐Fourier transform method is given. Finally, some numerical experimental results are also provided to demonstrate the effectiveness of the proposed WSRFT method.
Mechanical properties investigation of monolayer h-BN sheet under in-plane shear displacement using molecular dynamics simulations
Authors: Tian Y. , Li Z. , Gao W. , Cai K. , Wang F. , Zhang D. , Shirinzadeh B. , Fatikow S.
Published: January 2014

The mechanical properties, including wrinkling patterns and fracture behavior, of monolayer h-BN sheets have been investigated using classic molecular dynamics simulations and continuum model. The wrinkling pattern formation and evolution have been first explored. The dependences of the wrinkling shape, amplitude, and wavelength, as well as wrinkling number on shear displacement are extensively elucidated. The influences of geometry and shear load direction, as well as temperature, on the fracture behavior have also been studied to obtain further insights into the properties of the monolayer h-BN sheets.
Absolute radiant power measurement for the Au M lines of laser-plasma using a calibrated broadband soft X-ray spectrometer with flat-spectral response
Authors: Troussel Ph. , Villette B. , Emprin B. , Oudot G. , Tassin V. , Bridou F. , Delmotte F. , Krumrey M.
Published: January 2014

CEA implemented an absolutely calibrated broadband soft X-ray spectrometer called DMX on the Omega laser facility at the Laboratory for Laser Energetics (LLE) in 1999 to measure radiant power and spectral distribution of the radiation of the Au plasma. The DMX spectrometer is composed of 20 channels covering the spectral range from 50 eV to 20 keV. The channels for energies below 1.5 keV combine a mirror and a filter with a coaxial photo-emissive detector. For the channels above 5 keV the photoemissive detector is replaced by a conductive detector. The intermediate energy channels (1.5 keV < photon energy < 5 keV) use only a filter and a coaxial detector. A further improvement of DMX consists in flat-response X-ray channels for a precise absolute measurement of the photon flux in the photon energy range from 0.1 keV to 6 keV. Such channels are equipped with a filter, a Multilayer Mirror (MLM), and a coaxial detector. We present as an example the development of channel for the gold M emission lines in the photon energy range from 2 keV to 4 keV which has been successfully used on the OMEGA laser facility. The results of the radiant power measurements with the new MLM channel and with the usual channel composed of a thin titanium filter and a coaxial detector (without mirror) are compared. All elements of the channel have been calibrated in the laboratory of the Physikalisch-Technische Bundesanstalt, Germany's National Metrology Institute, at the synchrotron radiation facility BESSY II in Berlin using dedicated well established and validated methods.
Optical properties of titanium dioxide nanotube arrays
Authors: Abdelmoula Mohamed , Sokoloff Jeffrey , Lu Wen-Tao , Close Thomas , Menon Latika , Richter Christiaan
Published: January 2014

We present experimental measurements and a theoretical analysis of the near UV to NIR optical properties of free standing titania nanotube arrays. An improved understanding of the optical physics of this type of nanostructure is important to several next generation solar energy conversion technologies. We measured the transmission, reflection, and absorption of the electromagnetic spectrum from 300 nm to 1000 nm (UV to NIR) of titania nanotube arrays. We measured the total, specular, and diffuse reflection and transmission using both single point detection and an integrating sphere spectrometer. We find that the transmission, but not the reflection, of light (UV to NIR) through the nanotube array is well-explained by classic geometric optics using an effective medium model taking into account the conical geometry of the nanotubes. For wavelengths shorter than ∼500 nm, we find the surprising result that the reflection coefficient for light incident on the open side of the nanotube array is greater than the reflection coefficient for light incident on the closed “floor” of the nanotube array. We consider theoretical models based on the eikonal approximation, photonic crystal band theory, and a statistical treatment of scattering to explain the observed data. We attribute the fact that light with wavelengths shorter than 500 nm is more highly reflected from the open than the closed tube side as being due to disorder scattering inside the nanotube array.
Design of two dimensional silicon nanowire arrays for antireflection and light trapping in silicon solar cells
Authors: Ding Wuchang , Jia Rui , Li Haofeng , Chen Chen , Sun Yun , Jin Zhi , Liu Xinyu
Published: January 2014

Silicon nitride coated nanowire arrays have been investigated as an efficient antireflection structure for silicon solar cells. The minimum average reflectance could reach 1.62% under AM1.5 spectrum. Scattering effects of silicon nanowire arrays also result in enhanced absorption in the substrate, and analytical results show that the scattered light can be well trapped in silicon substrate when the back surface is passivated by silicon dioxide. This ultra-low surface reflection property combined with light trapping effect may have potential applications in silicon solar cells with thin substrate.
Nanoparticles at liquid interfaces: Rotational dynamics and angular locking
Authors: Razavi Sepideh , Kretzschmar Ilona , Koplik Joel , Colosqui Carlos E.
Published: January 2014

Nanoparticles with different surface morphologies that straddle the interface between two immiscible liquids are studied via molecular dynamics simulations. The methodology employed allows us to compute the interfacial free energy at different angular orientations of the nanoparticle. Due to their atomistic nature, the studied nanoparticles present both microscale and macroscale geometrical features and cannot be accurately modeled as a perfectly smooth body (e.g., spheres and cylinders). Under certain physical conditions, microscale features can produce free energy barriers that are much larger than the thermal energy of the surrounding media. The presence of these energy barriers can effectively “lock” the particle at specific angular orientations with respect to the liquid-liquid interface. This work provides new insights on the rotational dynamics of Brownian particles at liquid interfaces and suggests possible strategies to exploit the effects of microscale features with given geometric characteristics.
Absolute instability in viscoelastic mixing layers
Authors: Ray Prasun K. , Zaki Tamer A.
Published: January 2014

The spatiotemporal linear stability of viscoelastic planar mixing layers is investigated. A one-parameter family of velocity profiles is used as the base state with the parameter, S, controlling the amount of shear and backflow. The influence of viscoelasticity in dilute polymer solutions is modeled with the Oldroyd-B and FENE-P constitutive equations. Both models require the specification of the ratio of the polymer-relaxation and convective time scales (the Weissenberg number, We) and the ratio of solvent and solution viscosities (β). The maximum polymer extensibility, L, must also be specified for the FENE-P model. We examine how the variation of these parameters along with the Reynolds number, Re, affects the minimum value of S at which the flow becomes locally absolutely unstable. With the Oldroyd-B model, the influence of viscoelasticity is shown to be almost fully captured by the elasticity, \documentclass[12pt]{minimal}\begin{document}$E^* \equiv \frac{(1-\beta ) We}{Re}$\end{document}E*≡(1−β)WeRe, and Scrit decreases as elasticity is increased, i.e., elasticity is destabilizing. A simple approximate dispersion relation obtained via long-wave asymptotic analysis is shown to accurately capture this destabilizing influence. Results obtained with the FENE-P model exhibit a rich variety of behavior. At large values of the extensibility, L, results are similar to those for the Oldroyd-B fluid as expected. However, when the extensibility is reduced to more realistic values (L ≈ 100), one must consider the scaled shear rate, \documentclass[12pt]{minimal}\begin{document}$\eta _c \equiv \frac{We S}{2L}$\end{document}ηc≡WeS2L, in addition to the elasticity. When ηc is large, the base-state polymer stress obtained by the FENE-P model is reduced, and there is a corresponding reduction in the overall influence of viscoelasticity on stability. Additionally, elasticity exhibits a stabilizing effect which is driven by the streamwise-normal perturbation polymer stress. As ηc is reduced, the base-state and perturbation normal polymer stresses predicted by the FENE-P model move towards the Oldroyd-B values, and the destabilizing influence of elasticity observed with the Oldroyd-B model is again present.
Spin reorientation via antiferromagnetic coupling
Authors: Ranjbar M. , Sbiaa R. , Dumas R. K. , Åkerman J. , Piramanayagam S. N.
Published: January 2014

Spin reorientation in antiferromagnetically coupled (AFC) Co/Pd multilayers, wherein the thickness of the constituent Co layers was varied, was studied. AFC-Co/Pd multilayers were observed to have perpendicular magnetic anisotropy even for a Co sublayer thickness of 1 nm, much larger than what is usually observed in systems without antiferromagnetic coupling. When similar multilayer structures were prepared without antiferromagnetic coupling, this effect was not observed. The results indicate that the additional anisotropy energy contribution arising from the antiferromagnetic coupling, which is estimated to be around 6 × 106 ergs/cm3, induces the spin-reorientation.
Wideband ferrite substrate integrated waveguide isolator using shape anisotropy
Authors: Beguhn S. , Yang X. , Sun N. X.
Published: January 2014

A new variable bandwidth isolator implemented in a substrate integrated waveguide is presented. This design utilizes the shape anisotropy of ferrite multiple slabs to increase the demonstrated isolation bandwidth from ∼100 MHz to ∼1.2 GHz, over 10× increase, using commercially available polycrystalline ferrites. Over 10 dB of isolation with 2–3 dB of insertion loss is demonstrated. This device is also featured as a prototype fabrication with bulk substrates rather than a printed circuit board approach resulting in significant cost and time savings.
Effect of the spin-twist structure on the spin-wave dynamics in Fe55Pt45/Ni80Fe20 exchange coupled bi-layers with varying Ni80Fe20 thickness
Authors: Pal Semanti , Barman Saswati , Hellwig Olav , Barman Anjan
Published: January 2014

We have investigated optically induced ultrafast magnetization dynamics of a series of Fe55Pt45/Ni80Fe20 exchange spring bi-layers with varying Ni80Fe20 thickness. Rich spin-wave spectra are observed; whose frequency shows a strong dependence on the Ni80Fe20 layer thickness. Micromagnetic simulations based on a simplified magnetic microstructure were able to reproduce the experimental data qualitatively. The spin twist structure introduced in the Ni80Fe20 layer gives rise to new modes in the composite system as opposed to the bare Ni80Fe20 films.
Cubic-scaling algorithm and self-consistent field for the random-phase approximation with second-order screened exchange
Authors: Moussa Jonathan E.
Published: January 2014

The random-phase approximation with second-order screened exchange (RPA+SOSEX) is a model of electron correlation energy with two caveats: its accuracy depends on an arbitrary choice of mean field, and it scales as $\mathcal {O}(n^5)$O(n5) operations and $\mathcal {O}(n^3)$O(n3) memory for n electrons. We derive a new algorithm that reduces its scaling to $\mathcal {O}(n^3)$O(n3) operations and $\mathcal {O}(n^2)$O(n2) memory using controlled approximations and a new self-consistent field that approximates Brueckner coupled-cluster doubles theory with RPA+SOSEX, referred to as Brueckner RPA theory. The algorithm comparably reduces the scaling of second-order Møller-Plesset perturbation theory with smaller cost prefactors than RPA+SOSEX. Within a semiempirical model, we study H2 dissociation to test accuracy and Hn rings to verify scaling.
Effects of roughness and temperature on low-energy hydrogen positive and negative ion reflection from silicon and carbon surfaces
Authors: Tanaka N. , Kato S. , Miyamoto T. , Nishiura M. , Tsumori K. , Matsumoto Y. , Kenmotsu T. , Okamoto A. , Kitajima S. , Sasao M. , Wada M. , Yamaoka H.
Published: January 2014

Angle-resolved energy distribution functions of positive and negative hydrogen ions produced from a rough-finished Si surface under 1 keV proton irradiation have been measured. The corresponding distribution from a crystalline surface and a carbon surface are also measured for comparison. Intensities of positive and negative ions from the rough-finished Si are substantially smaller than those from crystalline Si. The angular distributions of these species are broader for rough surface than the crystalline surface. No significant temperature dependence for positive and negative ion intensities is observed for all samples in the temperature range from 300 to 400 K.
A study of the bending motion in tetratomic molecules by the algebraic operator expansion method
Authors: Larese Danielle , Caprio Mark A. , Pérez-Bernal Francisco , Iachello Francesco
Published: January 2014

We study the bending motion in the tetratomic molecules C2H2 (\documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ \documentclass[12pt]{minimal}\begin{document}$^1 \Sigma _g^+$\end{document}Σg+1), C2H2 (\documentclass[12pt]{minimal}\begin{document}$\tilde{A}$\end{document}Ã 1Au) trans-S1, C2H2 (\documentclass[12pt]{minimal}\begin{document}$\tilde{A}$\end{document}Ã 1A2) cis-S1, and \documentclass[12pt]{minimal}\begin{document}$\tilde{X}$\end{document}X̃ 1A1 H2CO. We show that the algebraic operator expansion method with only linear terms comprised of the basic operators is able to describe the main features of the level energies in these molecules in terms of two (linear) or three (trans-bent, cis-bent, and branched) parameters. By including quadratic terms, the rms deviation in comparison with experiment goes down to typically ∼10 cm−1 over the entire range of energy 0–6000 cm−1. We determine the parameters by fitting the available data, and from these parameters we construct the algebraic potential functions. Our results are of particular interest in high-energy regions where spectra are very congested and conventional methods, force-field expansions or Dunham-expansions plus perturbations, are difficult to apply.
Surface-resistance measurements using superconducting stripline resonators
Authors: Hafner Daniel , Dressel Martin , Scheffler Marc
Published: January 2014

We present a method to measure the absolute surface resistance of conductive samples at a set of GHz frequencies with superconducting lead stripline resonators at temperatures 1–6 K. The stripline structure can easily be applied for bulk samples and allows direct calculation of the surface resistance without the requirement of additional calibration measurements or sample reference points. We further describe a correction method to reduce experimental background on high-Q resonance modes by exploiting TEM-properties of the external cabling. We then show applications of this method to the reference materials gold, tantalum, and tin, which include the anomalous skin effect and conventional superconductivity. Furthermore, we extract the complex optical conductivity for an all-lead stripline resonator to find a coherence peak and the superconducting gap of lead.
Coaxial cable Bragg grating assisted microwave coupler
Authors: Huang Jie , Wei Tao , Fan Jun , Xiao Hai
Published: January 2014

This paper reports a microwave coupler based on two parallel coaxial cable Bragg gratings fabricated by drilling U-grooves across the cables at periodic distance along the cable direction. Electromagnetic field couplings between two cables were observed at discrete frequencies through both near and far ends detections. The coupling frequency and strength can be precisely controlled by varying the grating period and length. The coupling bandwidth may also be controlled through specific grating design. The device physics was also described through transfer matrix which matched well with the experimental results.
Physics design of the injector source for ITER neutral beam injector (invited)
Authors: Antoni V. , Agostinetti P. , Aprile D. , Cavenago M. , Chitarin G. , Fonnesu N. , Marconato N. , Pilan N. , Sartori E. , Serianni G. , Veltri P.
Published: January 2014

Two Neutral Beam Injectors (NBI) are foreseen to provide a substantial fraction of the heating power necessary to ignite thermonuclear fusion reactions in ITER. The development of the NBI system at unprecedented parameters (40 A of negative ion current accelerated up to 1 MV) requires the realization of a full scale prototype, to be tested and optimized at the Test Facility under construction in Padova (Italy). The beam source is the key component of the system and the design of the multi-grid accelerator is the goal of a multi-national collaborative effort. In particular, beam steering is a challenging aspect, being a tradeoff between requirements of the optics and real grids with finite thickness and thermo-mechanical constraints due to the cooling needs and the presence of permanent magnets. In the paper, a review of the accelerator physics and an overview of the whole R&D physics program aimed to the development of the injector source are presented.
Compact modeling of perpendicular nanomagnetic logic based on threshold gates
Authors: Breitkreutz Stephan , Eichwald Irina , Kiermaier Josef , Csaba Gyorgy , Schmitt-Landsiedel Doris , Becherer Markus
Published: January 2014

In this work, we show that physical-based compact modeling of perpendicular Nanomagnetic Logic is crucial for the design and simulation of complex circuitry. A compact model for field-coupled nanomagnets based on an Arrhenius switching model and finite element calculations is introduced. As physical parameters have an enormous influence on the behavior of the circuit, their modeling is of great importance. Exemplarily, a 1-bit full adder based on threshold logic gates is analyzed due to its reliability. The obtained findings are used to design a pure magnetic arithmetic logic unit, which can be used for basic Boolean and logic operations.
A non-contact fiber Bragg grating vibration sensor
Authors: Li Tianliang , Tan Yuegang , Wei Li , Zhou Zude , Zheng Kai , Guo Yongxing
Published: January 2014

A non-contact vibration sensor based on fiber Bragg grating (FBG) sensing has been proposed and studied in this paper. The principle of the sensor as well as simulation and experimental analyses are introduced. When the distance between the movable head and the measured shaft changed, the diaphragm deformed under magnetic coupling of the permanent magnet on the measured magnetic shaft. As a result, the center wavelength of the FBG connected to the diaphragm changed, based on which the vibration displacement of the rotating shaft could be obtained. Experimental results show that the resonant frequency of the sensor is about 1500 Hz and the working band ranges within 0–1300 Hz, which is consistent with the simulation analysis result; the sensitivity is −1.694 pm/μm and the linearity is 2.92% within a range of 2–2.4 mm. It can be used to conduct non-contact measurement on the vibration of the rotating shaft system.
Exchange bias induced by the fully strained La2/3Ca1/3MnO3 dead layers
Authors: Xie Q. Y. , Wu X. S. , Gao J. , Jia Q. J.
Published: January 2014

A pure compressively strained La2/3Ca1/3MnO3 (LCMO) dead layer grown on (001)-oriented LaAlO3 substrate can show all the rich phenomenon of large bias field shift, coercive field enhancement, and high blocking temperature. The obtained exchange bias field (∼350 Oe) and the enhanced coercivity of about 1160 Oe at 5 K under 500 Oe cooling field are superior to that have been reported in LCMO-based ferromagnetic/antiferromagnetic superlattices or nanoscale systems. Our results clearly demonstrate that the inhomogeneous magnetic dead layer of LCMO can induce a strong exchange bias effect, which may be exploited as a very simple structure for spin-valve device application.
Research Update: Progress in synthesis of nanoparticle dimers by self-assembly
Authors: Fernandez Yuri Diaz , Sun Lanlan , Gschneidtner Tina , Moth-Poulsen Kasper
Published: January 2014

This article highlights recent advances in the controlled self-assembly of nanoparticles to produce dimeric nanoparticle structures. The relevance of this emergent field is discussed in terms of recent applications in plasmonics and chemical catalysis. The concept of bond-valence applied to nanoparticles will be discussed, emphasizing some general approaches that have been successfully used to build these structures. Further, the asymmetric functionalization of nanoparticles surfaces as a path to drive selective aggregation, the use of biomolecules to self-assemble nanoparticles into dimers in solution, and the confinement of aggregates in small cavities are discussed.