bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast electron transfer in the nanocomposite of the graphene oxide–Au nanocluster with graphene oxide as a donor
Authors: Wen Xiaoming , Yu Pyng , Toh Yon-Rui , Lee Yu-Chieh , Huang Kuo-Yen , Huang Shujuan , Shrestha Santosh , Conibeer Gavin , Tang Jau
Published: March 2014

Novel electron transfer results in PL quenching in both graphene oxide–Au25 and graphene oxide–Au10 nanocomposites.
Synthesis, cytotoxicity and bioimaging of a novel Hg2+ selective fluorogenic chemosensor
Authors: Saleem Muhammad , Abdullah Razack , Ali Anser , Park Bong Joo , Choi Eun Ha , Hong In Seok , Lee Ki Hwan
Published: March 2014

A rhodamine B derivative 2 with terminal mercapto thiadiazole moiety was successfully synthesized and applied for selective recognition of Hg2+ in aqueous–acetonitrile (1 : 1, v/v, pH 7) solution by employing its photophysical properties.
Energy propagation throughout chemical networks
Authors: Le Saux Thomas , Plasson Raphaël , Jullien Ludovic
Published: March 2014

Fluxes of energy through cascades of reaction–diffusion cycles can sustain matter fluxes between spatially and chemically segregated zones.
Efficient syntheses of pillar[6]arene-based hetero[4]rotaxanes using a cooperative capture strategy
Authors: Hou Xisen , Ke Chenfeng , Cheng Chuyang , Song Nan , Blackburn Anthea K. , Sarjeant Amy A. , Botros Youssry Y. , Yang Ying-Wei , Stoddart J. Fraser
Published: March 2014

While one pillar[6]arene, nestling between two cucurbit[6]urils in a hetero[4]rotaxane, is conformationally mobile in solution, it adopts the energetically most favourable conformation with local C3V symmetry in the solid state.
Tungsten doped titanium dioxide nanowires for high efficiency dye-sensitized solar cells
Authors: Archana P. S. , Gupta Arunava , Yusoff Mashitah M. , Jose Rajan
Published: March 2014

Tungsten doping in TiO2 nanowires led to increased photocurrent density resulting from increased lifetime and dye-loading compared to niobium doping.
Theoretical study of core–shell composite structure made of carbon nanoring and aluminum nanowire
Authors: Chen Wei , Li Hui , He Yezeng
Published: March 2014

The super-short carbon nanoring can spontaneously wrap around the Al NW to form a double-deck helix
Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition
Authors: Toukabri Rim , Shi Yujun
Published: March 2014

At low filament temperatures and short reaction time, silylene chemistry dominates. The free-radical reactions become more important with increasing temperature and time.
TiO2(B) nanoparticle-functionalized WO3nanorods with enhanced gas sensing properties
Authors: Zhang Hongxin , Wang Shurong , Wang Yanshuang , Yang Jiedi , Gao Xueling , Wang Liwei
Published: March 2014

TiO2(B)–WO3nanorods exhibited fast response–recovery speeds, good reproducibility and good stability to several organic gases, indicating promising applications in gas sensing.
Separating the redox couple for highly efficient solid-state dye-sensitized solar cells
Authors: Li Juan , Zhang Wei , Zhang Lu , Wang Zhong-Sheng
Published: March 2014

The power conversion efficiency of a solid-state dye-sensitized solar cell was improved by >2.5-fold when the redox-couple was separated.
Understanding the growth and photoelectrochemical properties of mesocrystals and single crystals: a case of anatase TiO2
Authors: Hong Zhensheng , Dai Hong , Huang Zhigao , Wei Mingdeng
Published: March 2014

Anatase TiO2 mesocrystals demonstrate much enhanced photocurrent compared with that of TiO2 single crystals and P25.
Improved O2 evolution from a water splitting reaction over Er3+ and Y3+ co-doped tetragonal BiVO4
Authors: Obregón S. , Colón G.
Published: March 2014

Erbium–yttrium co-doped BiVO4 with a tetragonal structure is synthesized by means of a surfactant free hydrothermal method.
Preparation of layered double hydroxide/chlorophyll a hybrid nano-antennae: a key step
Authors: Sommer Márquez Alicia E. , Lerner Dan A. , Fetter Geolar , Bosch Pedro , Tichit Didier , Palomares Eduardo
Published: March 2014

From spinach to photonic nano-antennae: new chlorophylla/layered double hydroxide hybrids.
Long range charge transfer in trimetallic mixed-valence iron complexes mediated by redox non-innocent cyanoacetylide ligands
Authors: Gluyas Josef B. G. , Boden Andrew J. , Eaves Samantha G. , Yu Herrick , Low Paul J.
Published: March 2014

A redox active 9-atom, 10-bond –CC–CN{Fe(dppx)2}NC–CC– bridge is shown to be effective at promoting electron transfer between metal centres separated by some 15 Å.
Reactivity of food phenols with iron and copper ions: binding, dioxygen activation and oxidation mechanisms
Authors: Nkhili Ezzohra , Loonis Michèle , Mihai Simona , El Hajji Hakima , Dangles Olivier
Published: March 2014

In neutral phosphate buffer, common dietary phenols form stable complexes with iron ions. By contrast, the corresponding copper complexes are labile intermediates leading to phenol autoxidation.
Edible applications of shellac oleogels: spreads, chocolate paste and cakes
Authors: Patel Ashok R. , Rajarethinem Pravin S. , Grędowska Agnieszka , Turhan Ozge , Lesaffer Ans , De Vos Winnok H. , Van de Walle Davy , Dewettinck Koen
Published: March 2014

We demonstrate three potential edible applications of shellac oleogels as (i) a continuous oil phase for preparation of emulsifier-free, structured w/o emulsions (spreads), (ii) a replacer for oil-binders in chocolate paste formulations and (iii) a shortening alternative for cake preparation.
A handy liquid metal based electroosmotic flow pump
Authors: Gao Meng , Gui Lin
Published: March 2014

Pumping is as simple as drawing in this handy liquid metal based electroosmotic flow pump.
Binder free three-dimensional sulphur/few-layer graphene foam cathode with enhanced high-rate capability for rechargeable lithium sulphur batteries
Authors: Xi Kai , Kidambi Piran R. , Chen Renjie , Gao Chenlong , Peng Xiaoyu , Ducati Caterina , Hofmann Stephan , Kumar R. Vasant
Published: March 2014

A novel ultra-lightweight 3-D Li-S battery cathode has been synthesised by loading sulphur on to an interconnected 3-D network of few-layered graphene. The battery shows high rate discharge capacity retention for up to 400 cycles.
Homogeneous coating of photonic macroporous oxides with inorganic nanocrystals
Authors: Mitchell Robert , Brydson Rik , Douthwaite R. E.
Published: March 2014

A very simple method is described to achieve quantitative sub-monolayer nanoparticle (TiO2, Fe3O4 or CdS) coverage of photonic macroporous oxides.
Polypeptide micelles with dual pH activatable dyes for sensing cells and cancer imaging
Authors: Gong Ping , Yang Yueting , Yi Huqiang , Fang Shengtao , Zhang Pengfei , Sheng Zonghai , Gao Guanhui , Gao Duyang , Cai Lintao
Published: March 2014

We developed dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes. DPNs have good pH responses for solution and cells. Single acid activatable fluorescent dye doped nanoparticles can distinguish tumor tissue from normal tissue by monitoring the acidic extracellular environment.
Facile synthesis of Au–SnO2 hybrid nanospheres with enhanced photoelectrochemical biosensing performance
Authors: Shen Qingming , Jiang Jingyi , Liu Shilei , Han Li , Fan Xiaohui , Fan Mengxing , Fan Quli , Wang Lianhui , Huang Wei
Published: March 2014

Au–SnO2 hybrid nanospheres with enhanced photoelectrochemical biosensing performance were synthesized via a facile, one-step method.
van der Waals trilayers and superlattices: modification of electronic structures of MoS2 by intercalation
Authors: Lu Ning , Guo Hongyan , Wang Lu , Wu Xiaojun , Zeng Xiao Cheng
Published: March 2014

We perform a comprehensive first-principles study of the electronic properties of van der Waals (vdW) trilayers via intercalating a two-dimensional (2D) monolayer (ML = BN, MoSe2, WS2, or WSe2) between a MoS2 bilayer to form various MoS2/ML/MoS2 sandwich trilayers.
Thioanisole induced size-selective fragmentation of gold nanoparticles
Authors: Riaz Sara , Qu LuLu , Fodjo Essy Kouadio , Ma Wei , Long Yi-Tao
Published: March 2014

The size-selective fragmentation of gold nanoparticles (AuNPs) by thioanisole showed that large particles are more susceptible to fragmentation than the smaller ones.
A luminescent terbium coordination polymer for sensing methanol
Authors: Wang Hong-Ming , Liu Hui-Ping , Chu Tian-Shu , Yang Yang-Yi , Hu Yun-Song , Liu Wen-Ting , Ng Seik Weng
Published: March 2014

A new promising sensor for detecting methanol has been prepared, which exhibits highly sensitive and selective luminescence quenching to methanol.
SnO2 nanorod@TiO2 hybrid material for dye-sensitized solar cells
Authors: Huo Junchao , Hu Yanjie , Jiang Hao , Huang Wenjuan , Li Chunzhong
Published: March 2014

We have developed a novel SnO2 nanorod@TiO2 hybrid material by coating a layer of TiO2 on the surface of SnO2 nanorods. The power conversion efficiency (η) of the SnO2 nanorod@TiO2 hybrid material electrode is 6.98%, much higher than that of the SnO2 nanorods electrode (3.95%) and P25 electrode (5.27%).
A work-function tunable polyelectrolyte complex (PEI:PSS) as a cathode interfacial layer for inverted organic solar cells
Authors: Lin Zhenhua , Chang Jingjing , Zhang Jie , Jiang Changyun , Wu Jishan , Zhu Chunxiang
Published: March 2014

Incorporation of PSS into a PEI interfacial-layer improves the inverted-OPV, and it is further enhanced by using a robust TiOx–PEI:PSS combination.
Development of superoxide dismutase mimetic surfaces to reduce accumulation of reactive oxygen species for neural interfacing applications
Authors: Potter-Baker Kelsey A. , Nguyen Jessica K. , Kovach Kyle M. , Gitomer Martin M. , Srail Tyler W. , Stewart Wade G. , Skousen John L. , Capadona Jeffrey R.
Published: March 2014

In order to reduce inflammatory-mediated reactive oxygen species accumulation, we have developed an anti-oxidative surface modification consisting of a composite coating of adsorbed and immobilized superoxide dismutase mimetic.
Cyclometalated Ir(iii) complexes with styryl-BODIPY ligands showing near IR absorption/emission: preparation, study of photophysical properties and application as photodynamic/luminescence imaging materials
Authors: Majumdar Poulomi , Yuan Xiaolin , Li Shengfu , Le Guennic Boris , Ma Jie , Zhang Caishun , Jacquemin Denis , Zhao Jianzhang
Published: March 2014

Heteroleptic C^N cyclometalated iridium(iii) complexes showing strong NIR absorption were prepared.
RBR E3 ubiquitin ligases: new structures, new insights, new questions
Authors: Spratt Donald E. , Walden Helen , Shaw Gary S.
Published: March 2014

The RBR (RING-BetweenRING-RING) or TRIAD [two RING fingers and a DRIL (double RING finger linked)] E3 ubiquitin ligases comprise a group of 12 complex multidomain enzymes. This unique family of E3 ligases includes parkin, whose dysfunction is linked to the pathogenesis of early-onset Parkinson's disease, and HOIP (HOIL-1-interacting protein) and HOIL-1 (haem-oxidized IRP2 ubiquitin ligase 1), members of the LUBAC (linear ubiquitin chain assembly complex). The RBR E3 ligases share common features with both the larger RING and HECT (homologous with E6-associated protein C-terminus) E3 ligase families, directly catalysing ubiquitin transfer from an intrinsic catalytic cysteine housed in the C-terminal domain, as well as recruiting thioester-bound E2 enzymes via a RING domain. Recent three-dimensional structures and biochemical findings of the RBRs have revealed novel protein domain folds not previously envisioned and some surprising modes of regulation that have raised many questions. This has required renaming two of the domains in the RBR E3 ligases to more accurately reflect their structures and functions: the C-terminal Rcat (required-for-catalysis) domain, essential for catalytic activity, and a central BRcat (benign-catalytic) domain that adopts the same fold as the Rcat, but lacks a catalytic cysteine residue and ubiquitination activity. The present review discusses how three-dimensional structures of RBR (RING1-BRcat-Rcat) E3 ligases have provided new insights into our understanding of the biochemical mechanisms of these important enzymes in ubiquitin biology.
Human P450-like oxidation of diverse proton pump inhibitor drugs by ‘gatekeeper’ mutants of flavocytochrome P450 BM3
Authors: Butler Christopher F. , Peet Caroline , McLean Kirsty J. , Baynham Michael T. , Blankley Richard T. , Fisher Karl , Rigby Stephen E. J. , Leys David , Voice Michael W. , Munro Andrew W.
Published: March 2014

Production of drug metabolites is one area where enzymatic conversion has significant advantages over synthetic chemistry. These high value products are complex to synthesize, but are increasingly important in drug safety testing. The vast majority of drugs are metabolized by cytochromes P450 (P450s), with oxidative transformations usually being highly regio- and stereo-selective. The PPIs (proton pump inhibitors) are drugs that are extensively metabolized by human P450s, producing diverse metabolites dependent on the specific substrate. In the present paper we show that single mutations (A82F and F87V) in the biotechnologically important Bacillus megaterium P450 BM3 enzyme cause major alterations in its substrate selectivity such that a set of PPI molecules become good substrates in these point mutants and in the F87V/A82F double mutant. The substrate specificity switch is analysed by drug binding, enzyme kinetics and organic product analysis to confirm new activities, and X-ray crystallography provides a structural basis for the binding of esomeprazole to the F87V/A82F enzyme. These studies confirm that such ‘gatekeeper’ mutations in P450 BM3 produce major perturbations to its conformation and substrate selectivity, enabling novel P450 BM3 reactions typical of those performed by human P450s. Efficient transformation of several PPI drugs to human-like products by BM3 variants provides new routes to production of these metabolites.
Assessing Plural Morphology in Children Acquiring /S/-Leniting Dialects of Spanish
Authors: Miller Karen
Published: March 2014

Purpose

To examine the production of plural morphology in children acquiring a dialect of Spanish with syllable-final /s/ lenition with the goal of comparing how plural marker omissions in the speech of these children compare with plural marker omissions in children with language impairment acquiring other varieties of Spanish.

Method

Three production tasks were administered to children. A repetition task was used to examine children's production of the plural marker in plural noun phrases, and 2 Berko-style tasks evaluated children's production of the plural marker in bare nouns. Behavior on these tasks was compared with plural marker comprehension for each individual child.

Results

There was a correlation between children's comprehension of the plural marker and their production of the plural marker on plural noun phrases in the repetition task but not between comprehension and production of the plural marker on bare nouns in the Berko-style tasks.

Conclusions

Assessments of plural morphology as a clinical marker of language impairment in Spanish-speaking children may be problematic, especially in children acquiring dialects of Spanish with /s/ lenition, such as those originating in Chile, the Dominican Republic, Cuba, Puerto Rico, and Central America. Instead, for children acquiring /s/-leniting dialects of Spanish, assessments of the plural marker in noun phrases produced within a sentence frame may be a better indicator of acquisition than traditional Berko-style tasks that elicit bare nouns.
Robust fault detection and isolation for a class of uncertain single output non‐linear systems
Authors: Li Xiao‐Jian , Yang Guang‐Hong
Published: March 2014

The problem of robust fault detection and isolation (FDI) is studied for a class of uncertain single output non‐linear systems with q faults. By designing a switching law, a robust state observer is developed such that its state responses can asymptotically converge to the true system states for both fault‐free and faulty cases. Based on this robust state observer and other q  + 1 FDI observers, an efficient scheme is presented such that the FDI can be achieved for the considered single output non‐linear systems. The theoretical results are illustrated through an example of a single‐link flexible joint robot.
Effects of variable message sign on driver detours and identification of influencing factors
Authors: Kim Sangyoup , Choi Jaisung , Jeong Seungwon , Tay Richard
Published: March 2014

This study presents the results of an investigation made to determine the dominant influencing factors and their specific impacts on motorist detour making for variable message sign (VMS) placements on a freeway. This was necessary to provide engineers with a tool for evaluating VMS cost‐effectiveness and feasibility. The research found that additional travel time delay is the most influential variable in determining motorist detour making. In addition, more than 70% of freeway motorists recognise adjacent national roads as detour routes and both average annual daily traffic and the distance to the entering point of the detour path are found to be dominating factors. A motorist detour ratio model as a function of VMS placement on a freeway was developed based on these observations. In the model validation, actual detour making behaviours observed by revealed preference values showed some discrepancies, but these were minimal. These research findings should be useful for cost‐effective placement of VMS on freeways and it is recommended that the results be tested by practicing engineers in the intelligent transportation system sector.
One-Stage Biopsy, Debridement, Reconstruction, and Stabilization of Pyogenic Vertebral Osteomyelitis
Authors: Menon Venugopal K. , Kumar Kishore M. , Al Ghafri Khalifa
Published: March 2014

Study Design

Retrospective cohort study.

Objective

To evaluate whether the proposed one-stage biopsy, culture, debridement, and reconstruction with stabilization strategy is a viable option for pyogenic vertebral osteomyelitis (PVO). PVO is increasing in frequency globally, particularly in immunologically compromised individuals. Typically, biopsy and culture sensitivity followed by staged surgery and long-term antibiotic therapy is the mainstay of therapy.

Methods

This is a study of a group of 32 consecutive cases of PVO (spondylodiskitis) treated in our institution from 2010 to 2012. All cases had one-stage biopsy, culture sensitivity, debridement, reconstruction with iliac bone graft, and stabilization with titanium implants. The mean age in this series was 51 years, and the male-to-female ratio was 2.2:1. Approximately 50% of the patients had impaired immunity status. The commonest organism isolated was Pseudomonas aeruginosa. Culture-specific antibiotics were given for a minimum of 6 weeks to all patients. The follow-up period ranged from 6 months to a maximum of 2 years. All patients were assessed for wound healing, recurrence of infection, deformity progression, pain, and healing by radiologic and biochemical parameters. No generic or disease-specific outcome tools were used for this study.

Results

All patients had good wound healing, although there was one case of superficial infection that was resolved with debridement. There were two implant failures with pseudarthrosis and one localized kyphosis in this series.

Conclusions

The one-stage technique of biopsy, debridement, bone grafting, and stabilization can be recommended for most cases of PVO.
A Diagnosis of Maxillary Sinus Fracture with Cone-Beam CT: Case Report and Literature Review
Authors: Yilmaz Selmi Yardimci , Misirlioglu Melda , Adisen Mehmet Zahit
Published: March 2014

The purpose of this article is to present the case of maxillofacial trauma patient with maxillary sinus fracture diagnosed with cone-beam computed tomography (CBCT) and to explore the applications of this technique in evaluating the maxillofacial region. A 23-year-old male patient attempted to our clinic who had an injury at midface with complaints of swelling, numbness. The patient was examined before in emergency center but any diagnosis was made about the maxillofacial trauma. The patient re-examined clinically and radiographically. A fracture on the frontal wall of maxillary sinus is determined with the aid of CBCT. The patient consulted with the department of maxillofacial surgery and it is decided that any surgical treatment was not necessary. The emerging technique CBCT would not be the primary choice of imaging maxillofacial trauma. Nevertheless, when advantages considered this imaging procedure could be the modality of choice according to the case.
From products to product-service systems: IT-driven transformation of a medical equipment manufacturer
Authors: Fähling Jens , Köbler Felix , Leimeister Jan Marco , Krcmar Helmut
Published: March 2014

Meditec is a German manufacturer of instruments for surgeries. The company is quality leader in this sector and supplies many German and international hospitals. However, the opportunities for differentiation against competitors decrease continuously. New competitors from emerging markets are challenging the market position of established companies in this industry. Meditec is therefore forced to change its strategy and business model in order to survive in this novel competitive environment. The management of Meditec has decided to traverse from a pure product manufacturer to a customer-centric solution provider. This transformation requires the development of new processes, competencies and capabilities – especially with respect to IT and IT services. This teaching case helps in understanding the role of IT in product-service systems (PSS) and PSS-based business models. Therefore the case illustrates why IT is necessary to establish a PSS-based business model and why a customer-centric view is important for this kind of business model.
Magneto-optical spectroscopy of Co2FeSi Heusler compound
Authors: Veis M. , Beran L. , Antos R. , Legut D. , Hamrle J. , Pistora J. , Sterwerf Ch. , Meinert M. , Schmalhorst J.-M. , Kuschel T. , Reiss G.
Published: March 2014

Magneto-optical and electronic properties of the Co2FeSi Heusler compound were studied by polar Kerr magneto-optical spectroscopy and ab-initio calculations. The thin-film samples were grown by dc/rf magnetron co-sputtering on MgO(100) substrates. A Cr seed layer was deposited prior to the Co2FeSi layer to achieve its epitaxial growth. The magneto-optical spectroscopy was carried out using generalized magneto-optical ellipsometry with rotating analyzer in the photon energy range from 1.4 to 5.5 eV with an applied magnetic field of up to 1.2 T. The polar Kerr spectra showed a smooth spectral behavior up to 5.5 eV indicating nearly free charge carriers. Experimental data were compared with ab-initio calculations based on density functional theory employing the full-potential linearized augmented plane wave method.
Small-angle neutron scattering and magnetization study of HoNi2B2C
Authors: Ramazanoglu M. , Laver M. , Yagmurcu A. , Choi E.-M. , Lee S.-I. , Knigavko A. , Gaulin B. D.
Published: March 2014

The superconducting and magnetic properties of HoNi2B2C single crystals are investigated through transport, magnetometry and small-angle neutron scattering (SANS) measurements. In the magnetic phases that enter below the superconducting critical temperature, the small-angle neutron scattering data uncover networks of magnetic surfaces. These likely originate from uncompensated moments, e.g., at domain walls pinned to crystallo-graphic grain boundaries. The field and temperature dependent behavior of SANS appears consistent with the metamagnetic transitions reported in earlier works.
Interactions of aqueous amino acids and proteins with the (110) surface of ZnS in molecular dynamics simulations
Authors: Nawrocki Grzegorz , Cieplak Marek
Published: March 2014

The growing usage of nanoparticles of zinc sulfide as quantum dots and biosensors calls for a theoretical assessment of interactions of ZnS with biomolecules. We employ the molecular-dynamics-based umbrella sampling method to determine potentials of mean force for 20 single amino acids near the ZnS (110) surface in aqueous solutions. We find that five amino acids do not bind at all and the binding energy of the remaining amino acids does not exceed 4.3 kJ/mol. Such energies are comparable to those found for ZnO (and to hydrogen bonds in proteins) but the nature of the specificity is different. Cysteine can bind with ZnS in a covalent way, e.g., by forming the disulfide bond with S in the solid. If this effect is included within a model incorporating the Morse potential, then the potential well becomes much deeper—the binding energy is close to 98 kJ/mol. We then consider tryptophan cage, a protein of 20 residues, and characterize its events of adsorption to ZnS. We demonstrate the relevance of interactions between the amino acids in the selection of optimal adsorbed conformations and recognize the key role of cysteine in generation of lasting adsorption. We show that ZnS is more hydrophobic than ZnO and that the density profile of water is quite different than that forming near ZnO—it has only a minor articulation into layers. Furthermore, the first layer of water is disordered and mobile.
Insulator-based dielectrophoresis of mitochondria
Authors: Luo Jinghui , Abdallah Bahige G. , Wolken Gregory G. , Arriaga Edgar A. , Ros Alexandra
Published: March 2014

Isolated mitochondria display a wide range of sizes plausibly resulting from the coexistence of subpopulations, some of which may be associated with disease or aging. Strategies to separate subpopulations are needed to study the importance of these organelles in cellular functions. Here, insulator-based dielectrophoresis (iDEP) was exploited to provide a new dimension of organelle separation. The dielectrophoretic properties of isolated Fischer 344 (F344) rat semimembranosus muscle mitochondria and C57BL/6 mouse hepatic mitochondria in low conductivity buffer (0.025–0.030 S/m) at physiological pH (7.2–7.4) were studied using polydimethylsiloxane (PDMS) microfluidic devices. First, direct current (DC) and alternating current (AC) of 0–50 kHz with potentials of 0–3000 V applied over a channel length of 1 cm were separately employed to generate inhomogeneous electric fields and establish that mitochondria exhibit negative DEP (nDEP). DEP trapping potential thresholds at 0–50 kHz were also determined to be weakly dependent on applied frequency and were generally above 200 V. Second, we demonstrated a separation scheme using DC potentials <100 V to perform the first size-based iDEP sorting of mitochondria. Samples of isolated mitochondria with heterogeneous sizes (150 nm–2 μm diameters) were successfully separated into sub-micron fractions, indicating the ability to isolate mitochondria into populations based on their size.
Optically controlled excitonic transistor
Authors: Andreakou P. , Poltavtsev S. V. , Leonard J. R. , Calman E. V. , Remeika M. , Kuznetsova Y. Y. , Butov L. V. , Wilkes J. , Hanson M. , Gossard A. C.
Published: March 2014

Optical control of exciton fluxes is realized for indirect excitons in a crossed-ramp excitonic device. The device demonstrates experimental proof of principle for all-optical excitonic transistors with a high ratio between the excitonic signal at the optical drain and the excitonic signal due to the optical gate. The device also demonstrates experimental proof of principle for all-optical excitonic routers.
Insight into instabilities in burning droplets
Authors: Miglani Ankur , Basu Saptarshi , Kumar Ranganathan
Published: March 2014

The complex multiscale physics of nano-particle laden functional droplets in a reacting environment is of fundamental and applied significance for a wide variety of applications ranging from thermal sprays to pharmaceutics to modern day combustors using new brands of bio-fuels. Formation of homogenous nucleated bubbles at the superheat limit inside vaporizing droplets (with or without nanoparticles) represents an unstable system. Here we show that self-induced boiling in burning functional pendant droplets can produce severe volumetric shape oscillations. Internal pressure build-up due to ebullition activity ejects bubbles from the droplet domain causing undulations on the droplet surface and oscillations in bulk. Through experiments, we establish that the degree of droplet deformation depends on the frequency and intensity of these bubble expulsion events. In a distinct regime of single isolated bubble residing in the droplet, however, pre-ejection transient time is identified by Darrieus-Landau evaporative instability, where bubble-droplet system behaves as a synchronized driver-driven system with bulk bubble-shape oscillations being imposed on the droplet. The agglomeration of nanophase additives modulates the flow structures within the droplet and also influences the bubble inception and growth leading to different levels of instabilities.
Shape and area fluctuation effects on nucleation theory
Authors: Prestipino Santi , Laio Alessandro , Tosatti Erio
Published: March 2014

In standard nucleation theory, the nucleation process is characterized by computing ΔΩ(V), the reversible work required to form a cluster of volume V of the stable phase inside the metastable mother phase. However, other quantities besides the volume could play a role in the free energy of cluster formation, and this will in turn affect the nucleation barrier and the shape of the nucleus. Here we exploit our recently introduced mesoscopic theory of nucleation to compute the free energy cost of a nearly spherical cluster of volume V and a fluctuating surface area A, whereby the maximum of ΔΩ(V) is replaced by a saddle point in ΔΩ(V, A). Compared to the simpler theory based on volume only, the barrier height of ΔΩ(V, A) at the transition state is systematically larger by a few kBT. More importantly, we show that, depending on the physical situation, the most probable shape of the nucleus may be highly non-spherical, even when the surface tension and stiffness of the model are isotropic. Interestingly, these shape fluctuations do not influence or modify the standard Classical Nucleation Theory manner of extracting the interface tension from the logarithm of the nucleation rate near coexistence.
Crystallization properties of materials along the pseudo-binary line between GeTe and Sb
Authors: Cheng Huai-Yu , Raoux Simone , Jordan-Sweet Jean L.
Published: March 2014

GeTe is a well-know prototypical phase change material, while pure Sb is described as a material with strong resonant bonding properties which are indicative of a fast switching phase change material. We have studied the crystallization times and crystallization temperatures of phase-change materials along the GeTe-Sb pseudobinary line with compositions Ge1SbxTe1. It was observed that alloys with x ≈ 1–2 show the highest crystallization temperature and resistance in the crystalline phase (indicative of low reset current) but also the slowest crystallization speed. As many phase change materials, Ge1SbxTe1 materials also suffer from conflicting requirements between speed, thermal stability of the amorphous phase, and low reset current. The Ge-Sb-Te phase-change material compositions must be carefully designed to optimize device performance for a specific application. Ge1Sb6Te1 material is a promising candidate for storage-class memory with fast speed and a crystallization temperature that is substantially higher than Ge2Sb2Te5 thus promises good data retention.
Selective formation of large-grained, (100)- or (111)-oriented Si on glass by Al-induced layer exchange
Authors: Toko K. , Numata R. , Saitoh N. , Yoshizawa N. , Usami N. , Suemasu T.
Published: March 2014

By controlling the Si thickness and the annealing temperature used for Al-induced crystallization, we controlled the fraction of (100) and (111) orientations of polycrystalline Si (poly-Si) grains grown on glass. Changing the proportions of crystal orientation strongly influenced the average grain size of the poly-Si layer. By growing a 99% (111)-oriented poly-Si layer, formed with a 50-nm-thick Si layer at 375 °C, we produced a Si layer with grains nearly 40 μm in size. We discuss the growth mechanism from the perspective of competition between (100)- and (111)-oriented nuclei. This achievement holds promise for fabricating high-efficiency thin-film solar cells on inexpensive glass substrates.
Thin films of the spin ice compound Ho2Ti2O7
Authors: Leusink D. P. , Coneri F. , Hoek M. , Turner S. , Idrissi H. , Van Tendeloo G. , Hilgenkamp H.
Published: March 2014

The pyrochlore compounds Ho2Ti2O7 and Dy2Ti2O7 show an exotic form of magnetism called the spin ice state, resulting from the interplay between geometrical frustration and ferromagnetic coupling. A fascinating feature of this state is the appearance of magnetic monopoles as emergent excitations above the degenerate ground state. Over the past years, strong effort has been devoted to the investigation of these monopoles and other properties of the spin ice state in bulk crystals. Here, we report the fabrication of Ho2Ti2O7 thin films using pulsed laser deposition on yttria-stabilized ZrO2 substrates. We investigated the structural properties of these films by X-ray diffraction, scanning transmission electron microscopy, and atomic force microscopy, and the magnetic properties by vibrating sample magnetometry at 2 K. The films not only show a high crystalline quality, but also exhibit the hallmarks of a spin ice: a pronounced magnetic anisotropy and an intermediate plateau in the magnetization along the [111] crystal direction.
Accurate spectral response measurements of a complementary absorbing organic tandem cell with fill factor exceeding the subcells
Authors: Cheyns David , Kim Minjae , Verreet Bregt , Rand Barry P.
Published: March 2014

Single heterojunction organic photovoltaic cells based on co-evaporated donor–acceptor layers with power conversion efficiencies (η) above 5.5% are demonstrated, using either high (1.8 eV) or low (1.4 eV) optical gap materials. The high energy absorbing cell utilizes a high fullerene-C70 content, in combination with a high mobility amorphous donor, while the low energy absorbing cell consists of a donor–acceptor molecule paired with C60 as the acceptor. The integration of the two cells in an optimized tandem configuration leads to η =7.2%, verified by external quantum efficiency measurements of the subcells. Notably, the fill-factor of the tandem stack is higher than either one of the sub-cells.
Field emission properties of chemical vapor deposited individual graphene
Authors: Zamri Yusop Mohd , Kalita Golap , Yaakob Yazid , Takahashi Chisato , Tanemura Masaki
Published: March 2014

Here, we report field emission (FE) properties of a chemical vapor deposited individual graphene investigated by in-situ transmission electron microscopy. Free-standing bilayer graphene is mounted on a cathode microprobe and FE processes are investigated varying the vacuum gap of cathode and anode. The threshold field for 10 nA current were found to be 515, 610, and 870 V/μm for vacuum gap of 400, 300, and 200 nm, respectively. It is observed that the structural stability of a high quality bilayer graphene is considerably stable during emission process. By contacting the nanoprobe with graphene and applying a bias voltage, structural deformation and buckling are observed with significant rise in temperature owing to Joule heating effect. The finding can be significant for practical application of graphene related materials in emitter based devices as well as understanding the contact resistance influence and heating effect.
Effects of magnetic electrode on the ferroelectric properties in heteroepitaxial BiFeO3/La0.625Ca0.375MnO3 thin films
Authors: Feng L. , Yang S. W. , Liu Y. K. , Yin Y. W. , Dong S. N. , Jiang T. , Li X. G. , Zeng Z.
Published: March 2014

The ferroelectric properties of the BiFeO3/La0.625Ca0.375MnO3 (BFO/LCMO) heterostructures were investigated using different bottom electrode configurations at different magnetic fields and temperatures. It is found that the apparent coercive voltage (Vac) increases linearly with the increase of LCMO resistances for different electrodes, and the extrinsic relative contribution from different LCMO electrodes to the variation of Vac caused by magnetic field can be quantitatively analyzed based on the scenario of voltage drop model. The magnetic field and temperature dependences of the heterostructure coercive voltage (Vac0) obtained by subtracting the voltage drop on LCMO from Vac are closely related to the interface behaviors. These findings not only further elucidate the physics of magnetoelectric coupling in multiferroic heterostructures but also are helpful for designing artificial prototype device.
Optical-lattice clock sets new standard for timekeeping
Authors: Smart Ashley G.
Published: March 2014

The clock’s strength is in numbers; instead of ticking to the rhythm of a single atom, it synchronizes with thousands of atoms at once.
A nanoscale look at how soil captures carbon
Authors: Miller Johanna L.
Published: March 2014

Organic matter bound to mineral grains can remain there for many decades. But only a fraction of the mineral surface area ever binds any carbon.
Observations of breeding behaviour and possible infanticide in a wild population of Tasmanian echidnas (Tachyglossus aculeatus setosus)
Authors: Harris Rachel L. , Nicol Stewart C.
Published: March 2014

We describe field observations of Tasmanian echidna behaviour, including possible infanticide, where males damaged and entered nursery burrows. We also present the second report of a female producing a second offspring within a single reproductive season after the loss of her first young at an early stage.
Potential gender and age differences in the performance of five condom-related behaviours in the United Kingdom
Authors: Hancock Jude
Published: March 2014

Safer sex is important and comprises of a series of five condom-related behaviours: accessing, carrying, negotiating, using and disposing. This study explored potential gender and age differences in these condom-related behaviours. Data suggests gender differences exist for accessing, carrying and disposing behaviours. An age difference was seen in accessing behaviour. Therefore future safer sex interventions should acknowledge the potential gender and age differences in these condom-related behaviours.
Four-dimensional live imaging of apical biosynthetic trafficking reveals a post-Golgi sorting role of apical endosomal intermediates
Authors: Thuenauer Roland , Hsu Ya-Chu , Carvajal-Gonzalez Jose Maria , Deborde Sylvie , Chuang Jen-Zen , Römer Winfried , Sonnleitner Alois , Rodriguez-Boulan Enrique , Sung Ching-Hwa
Published: March 2014

Significance

The establishment and maintenance of epithelial polarity relies on the tight regulation of vesicular trafficking, which ensures that apical and basolateral membrane proteins reach their designated plasma membrane domains. Here, we report the direct visualization of biosynthetic
trans
-endosomal trafficking of apically targeted rhodopsin in polarized epithelial cells. Our work provides novel insights into the crosstalk between biosynthetic and endocytic pathways. We demonstrate that the small GTPase Rab11a regulates sorting at apical recycling endosomes (AREs) and is also implicated in carrier vesicle docking at the apical plasma membrane. We further unveil a surprising role for dynamin-2 in the release of apical carriers from AREs. Our data indicate that
trans
-endosomal trafficking is indispensable for accurate and high-fidelity apical delivery.
Principles of scientific research team formation and evolution
Authors: Milojević Staša
Published: March 2014

Significance

Science is an activity with far-reaching implications for modern society. Understanding how the social organization of science and its fundamental unit, the research team, forms and evolves is therefore of critical significance. Previous studies uncovered important properties of the internal structure of teams, but little attention has been paid to their most basic property: size. This study fills this gap by presenting a model that successfully explains how team sizes in various fields have evolved over the past half century. This model is based on two principles: (i) smaller (core) teams form according to a Poisson process, and (ii) larger (extended) teams begin as core teams but consequently accumulate new members through the process of cumulative advantage based on productivity.
Tumor suppressor role of phospholipase Cε in Ras-triggered cancers
Authors: Martins Marta , McCarthy Afshan , Baxendale Rhona , Guichard Sabrina , Magno Lorenza , Kessaris Nicoletta , El-Bahrawy Mona , Yu Philipp , Katan Matilda
Published: March 2014

Significance

Ras oncogens have been implicated in high proportion of cancers. However, selective treatment for Ras oncogenes is not yet available and components that could mediate Ras functions are being extensively assessed as alternative targets. For some potential targets, such as phospholipase Cε (PLCε), it is not clear how they contribute to tumor development. Here we provide several lines of experimental evidence that support a tumor suppressor function of PLCε, contrasting a positive role of several other well-defined effectors of Ras. Our results show a tumor suppressor role for this PLC in animal models and describe its impact on cell proliferation. Together with observations of marked down-regulation in several types of tumors, this study suggests its use as a biological marker in cancer.
Activating mutations in
STIM1
and
ORAI1
cause overlapping syndromes of tubular myopathy and congenital miosis
Authors: Nesin Vasyl , Wiley Graham , Kousi Maria , Ong E-Ching , Lehmann Thomas , Nicholl David J. , Suri Mohnish , Shahrizaila Nortina , Katsanis Nicholas , Gaffney Patrick M. , Wierenga Klaas J. , Tsiokas Leonidas
Published: March 2014

Significance

Stormorken syndrome is a rare autosomal-dominant genetic condition characterized by congenital miosis, bleeding diathesis, thrombocytopenia, and proximal muscle weakness. Other manifestations include functional or anatomical asplenia, ichthyosis, headaches, and dyslexia. A milder form of Stormorken syndrome is associated with muscle weakness and congenital miosis, but without hematologic abnormalities. Here we identify the gene mutations responsible for these syndromes and show that both conditions are caused by the hyperactivation of the Ca
2+
release-activated Ca
2+
(CRAC) channel. These findings contrast the pathologies associated with loss or diminished function of the CRAC channel, provide new molecular insights of the function of the CRAC channel, and suggest new approaches to combat these conditions by blocking CRAC channel activity.
Increasing homogeneity in global food supplies and the implications for food security
Authors: Khoury Colin K. , Bjorkman Anne D. , Dempewolf Hannes , Ramirez-Villegas Julian , Guarino Luigi , Jarvis Andy , Rieseberg Loren H. , Struik Paul C.
Published: March 2014

Significance

This study provides evidence of change in the relative importance of different crop plants in national food supplies worldwide over the past 50 years. Within a global trend of increased overall quantities of food calories, protein, fat, and weight, and increased proportions of those quantities sourcing from energy-dense foods, national food supplies diversified in regard to contributing measured crop commodities. As a consequence, national food supplies globally have become increasingly similar in composition, based upon a suite of truly global crop plants. The growth in reliance worldwide on these crops heightens interdependence among countries in their food supplies, plant genetic resources, and nutritional priorities.
Categorical encoding of color in the brain
Authors: Bird Chris M. , Berens Samuel C. , Horner Aidan J. , Franklin Anna
Published: March 2014

Significance

Humans group the millions of discriminable colors into discrete categories, such as “blue” and “green.” There has been much debate about where color categories come from; for example, whether color categories are inbuilt into the visual system. We use functional MRI to identify regions of the brain that categorize color. Color categories are encoded by regions of the frontal lobes, which also categorize other information (e.g., sounds). Interestingly, the visual cortex responds only to the size of color differences, but not color categories. We conclude that color categories occur at the level of attention rather than being inbuilt into the visual system. The findings shed light on how the brain categorizes information and how it processes color.
Myosin lever arm directs collective motion on cellular actin network
Authors: Hariadi Rizal F. , Cale Mario , Sivaramakrishnan Sivaraj
Published: March 2014

Significance

Myosins function as groups of motors anchored to a cellular scaffold that interacts with neighboring actin filaments patterned in complex three-dimensional networks. Although much is known about the function of individual myosin molecules, the contribution of intermotor interactions to collective movement is poorly understood. We used a precisely engineered biomimetic system to investigate how the mechanics of a structural element in the individual myosin influences the collective motion of groups of motors. Stochastic simulations suggest that the interplay between intramolecular strain on the motor lever arm and intermotor tension dictates trajectory shapes in groups of identical and antagonistic motors. Our study provides a general approach to dissecting emergence in cellular processes with applications for the efficient synthetic design of molecular transport systems.
Molecular interferometer to decode attosecond electron–nuclear dynamics
Authors: Palacios Alicia , González-Castrillo Alberto , Martín Fernando
Published: March 2014

Significance

Current attosecond technologies designed to study fast electron and nuclear motion in molecules make use, at some stage, of infrared laser pulses that strongly perturb the molecular potential, thus modifying the dynamics inherent to the system. To access the actual dynamics of the molecule, gentler laser sources must be used. Very recently, extreme UV pulses have been successfully combined to provide a picture of the intrinsic electron dynamics in atoms with subfemtosecond time resolution. Here we show that by using two identical extreme UV pulses, one can also obtain a complete description of the coupled electronic and nuclear dynamics in molecules. Visualization of such dynamics is possible by varying the wavelength and/or the time delay between the two pulses.
Anisotropic two-dimensional electron gas at SrTiO
3
(110)
Authors: Wang Zhiming , Zhong Zhicheng , Hao Xianfeng , Gerhold Stefan , Stöger Bernhard , Schmid Michael , Sánchez-Barriga Jaime , Varykhalov Andrei , Franchini Cesare , Held Karsten , Diebold Ulrike
Published: March 2014

Significance

Although still in its infancy, electronics based on all-oxide materials is a rapidly developing field, and strontium titanate is its key player. For this area to thrive, an atomic-scale control and understanding of the materials’ surfaces and interfaces needs to be achieved. A SrTiO
3
crystal with (110) orientation automatically forms an overlayer that is more insulating than the bulk and chemically less reactive, akin to the native SiO
2
on conventional wafer. With appropriate doping a two-dimensional electron gas (2DEG) forms underneath the SrTiO
3
(110) surface. This (110) 2DEG is very different from (001): The effective mass here depends on the quantum number, and a completely flat band can be realized. Such a flat band bears good prospects for, among others, magnetism and thermoelectricity.