bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction to Food Biosensors
Authors: Lim Syazana Abdullah , Ahmed Minhaz Uddin
Published: October 2016

This chapter is divided into sections introducing the principal concept of a biosensor and describing the different key elements in its construction. A discussion of various natural and synthetic receptors used in molecular biorecognition, their interactions with analytes and limitations are included. This chapter is also devoted in providing readers an overview of different configurations of transducer, advantages and drawbacks of each method. As a conclusion, an emerging trend of biosensors as a useful analytical tool will be evaluated.
Innovative Tools with Miniaturized Devices for Food Biosensing
Authors: Witkowska Nery Emilia K. , da Silva Everson T. S. G. , Kubota Lauro T.
Published: October 2016

Screening for biological and chemical contaminants and monitoring of nutrients are some of the crucial challenges for quality assessment of food and consumer safety. Although conventional techniques provide high specificity and selectivity, these methods are normally time consuming, expensive, need trained staff to carry out the tests in a centralized laboratory, and are not always compatible with all the stages of food production and the distribution chain. To overcome those limitations, a lot of effort has been made recently to develop simple, low-cost, and sensitive miniaturized devices. Thus, in this chapter we present some of the aspects of miniaturized systems used in food biosensing, from the construction of these platforms to application in food analysis, as well as the perspective and future directions of these technologies.
Glucose, Glutamate, and Lactate Sensors for Measuring Food Components
Authors: Koide S.
Published: October 2016

We have developed a variety of microplanar amperometric biosensors for measuring glucose, glutamate, and lactate concentrations in food. The microplanar electrodes of the sensor chip were manufactured by sputtering Pt and Ag onto the substrate surface. The reference electrode was a AgCl electrode pretreated by electrolysing Ag on the substrate in FeCl3 solution. Four membrane layers were fabricated on the electrode surface of the sensor chip by spin-coating a γ-aminopropyl triethoxy silane solution, a Nafion dispersion, an enzyme (glucose oxidase, glutamate oxidase, or lactate oxidase) and glutaraldehyde solution, and a fluorocarbon resin dispersion. The membrane layers provided a fast response time, low interference from other substances in the samples, and a wide dynamic range. These biosensors enable accurate measurements of the target substances.
Biosensor Platforms for Detecting Target Species in Milk Samples
Authors: Booth Marsilea A. , Karaosmanoglu Hande , Wu Yinqiu , Partridge Ashton
Published: October 2016

Milk testing is able to provide a valuable, non-invasive resource for monitoring the biometrics of an animal, in particular for the agricultural monitoring of cows. Information of interest includes the presence and concentrations of such compounds as lactose, antibiotics and hormones. The former two can give an indication of animal health as well as the suitability for human consumption, while the latter provides information on animal fertility. Within the milk matrix exists a range of compounds including proteins, fats, and sugars that can serve to complicate the detection of target species, or may indeed be the target compounds of the sensors. Biosensor platforms can combine the selectivity and sensitivity of biological systems together with the potential for straightforward sensor read-out, rapidity, portability and automation for online analysis. However, there are hurdles to overcome to provide stable, sensitive, reproducible sensors able to perform measurements in the real-sample milk matrix. This chapter describes milk components, specific compounds that may be detected in milk, biosensing methodologies for milk sample analysis, and a review of selected literature, focusing specifically on the milk matrix and real sample testing.
Bionanotechnology-Based Colorimetric Sensors for Food Analysis
Authors: Ying Jean Liew Zhi , Lim Lee Hoon , Mirza Aminul Huq , Ahmad Norhayati , Rahman Ibrahim Abd , Ahmed Minhaz Uddin
Published: October 2016

Colorimetric biosensing is widely used in clinical diagnosis and environmental evaluation due to its simplicity and practicality. It has also recently become popular in food analysis. Nanotechnology is being integrated into the development of colorimetric biosensors to overcome the bottleneck of conventional colorimetric biosensing approaches. Innovative bionanotechnology-based colorimetric sensors have recently been developed. This chapter focuses on the progress of bionanotechnology-based colorimetric biosensors in food safety assessment. We also describe how nanomaterials can be integrated and tailored to meet the requirements of colorimetric biosensing systems for the detection of heavy metal cations, antibiotics, nucleic acids, and toxins/toxicants. Approaches described include functionalization of nanomaterials to act as colorimetric probes, carriers and enzyme mimetics. Selected examples of the most recent preliminary applications of bionanotechnology-based colorimetric biosensors in food safety assessment are given to illustrate the novel concepts and promising future applications. Future prospects for the application of bionanotechnology-based colorimetric biosensors in food safety assessment are also briefly discussed.
Nanomaterial-Based Electrochemical Sensors for Highly Sensitive Detection of Foodborne Pathogens
Authors: Oaew Sukunya , Lertanantawong Benchaporn , Rijiravanich Patsamon , Somasundrum Mithran , Surareungchai Werasak
Published: October 2016

In this chapter we briefly survey the main foodborne pathogens in terms of their causes, symptoms and impact on human health. We have described the principles of detection for some important analytes by conventional means and by electrochemical biosensors using either immunoassay or nucleic acid assay. We provide a survey of the use of nanomaterials in such biosensors, both in terms of the possible electrode modifications that are available to increase the sensor response, and in terms of how nanomaterials can be used to construct labels for electrochemical biosensors.
Food Biosensors Based on Molecularly Imprinted Polymers
Authors: Koirala Kisan , Santos Jose H. , Sevilla III Fortunato B.
Published: October 2016

This chapter provides an overview of recent progress towards the design, synthesis, and application of molecularly imprinted polymers (MIPs) as food biosensors. Molecular imprinting is an innovative approach for mimicking natural molecular recognition processes through the preparation of synthetic recognition systems. MIPs are rapidly becoming viable alternatives to natural antibodies for sensor technology. The use of MIPs as sensors for determining the presence of contaminants in food has attracted considerable interest from numerous researchers and earned these materials a special niche as analytical devices for assessing food safety. Research on MIPs is an evolving field with a wide range of applications in manufacturing, processing, analysis, and quality control of foodstuffs. MIPs have several advantages for these uses, including high sensitivity, selectivity and portability, as well as their requirement for small samples. A variety of different transducers have been developed for food sensing, including optical, electrochemical, and mass-based sensors, which are discussed in detail in this chapter.
Rapid Detection of Food Pathogens by Portable and On-Site Electrochemical DNA Sensors
Authors: Yamanaka Keiichiro , Saito Masato
Published: October 2016

DNA analysis such as PCR has become a powerful tool for food sanitation control due to its rapid detection capability with high sensitivity and selectivity. In this chapter, electrochemical DNA detection for E. coli and Salmonella via PCR and LAMP is introduced. We describe electrochemical measurements using electroactive DNA intercalating dye, bisbenzimidazole trihydrochloride for PCR, and methylene blue for LAMP. The peak current decreases when DNA is amplified, because the diffusion of dye-amplified DNA complex becomes slower on the electrode surface. Therefore, decreased peak current of indicator indicates DNA amplification, and the degree of reduction is related to the quantity of amplified DNA. The electrochemical-based DNA detection method presented here is a simple technique, using a screen-printed electrode and hand-held potentiostat. The screen-printed electrode is easy and inexpensive to produce in bulk, thereby offering disposable usage. This is advantageous for PCR and LAMP, because it can avoid contamination, which can be a major problem in these highly sensitive DNA amplification methods. The use of a hand-held potentiostat also makes this method suitable for the development of an on-site food testing system.
Isothermal DNA Amplification Strategies for Food Biosensors
Authors: Roy Sharmili , Hossain Mohammad Mosharraf , Safavieh Mohammadali , Lubis Hamadah Nur , Zourob Mohammed , Ahmed Minhaz Uddin
Published: October 2016

Rapid, sensitive, and selective pathogen detection in food industry is of paramount importance for global health. Currently available diagnostic assays based on polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), which are time-consuming, complex, and relatively expensive, are ill suited to meet the current requirements for pathogen detection in the food industry. Different isothermal amplification techniques are faster, more sensitive, and more robust compared to other standard pathogen detection methods. Modern techniques are based on molecular diagnostics integrated with various detection modalities such as bioanalytical, electrochemical, and luminescence techniques to ensure more sensitive and specific detection processes. Here, we review conventional and non-conventional techniques for pathogen detection on food industry. We focus mainly on nucleic acid detection integrated with electrochemical biosensors. In addition, the applications of nanoparticle biosensors and colorimetric sensors are reviewed. Lab-on-a-chip (LOC) devices based on design strategies utilizing isothermal amplification for pathogen detection are also discussed.
Rapid visualization of macromolecular orientation by discrete frequency mid-infrared spectroscopic imaging
Authors: Wrobel Tomasz P. , Mukherjee Prabuddha , Bhargava Rohit
Published: October 2016

Large samples of semi-crystalline polymer can be rapidly visualized by polarization sensitive discrete frequency infrared (DFIR) spectroscopic imaging using a quantum cascade laser (QCL).
Alkaline-earth phosphonate MOFs with reversible hydration-dependent fluorescence
Authors: Fard Z. H. , Kalinovskyy Y. , Spasyuk D. M. , Blight B. A. , Shimizu G. K. H.
Published: October 2016

A new rigid tritopic phosphonic ligand, 2,4,6-tris(4-phosphonophenyl)pyridine (H6L), was synthesized and used to assemble isostructural barium (1) and strontium (2) phosphonate metal organic frameworks that exhibit fully reversible and selective water-dependent fluorescence red-shift at room temperature.
Highly efficient blue solid emitters and tautomerization-induced ON/OFF fluorescence switching based on structurally simple 3(5)-phenol-1H-pyrazoles
Authors: Tang Baolei , Zhang Houyu , Ye Kaiqi , Zhang Hongyu , Wang Yue
Published: October 2016

3(5)-Phenyl-1H-pyrazoles are employed in this study to develop highly efficient organic crystalline solids with deep-blue ESIPT fluorescence as well as intriguing fluorescence “ON/OFF” switching.
Composition variation in Al-based dilute nitride alloys using apertureless scanning near-field optical microscopy
Authors: Kolhatkar G. , Boucherif A. , Dab C. , Fafard S. , Aimez V. , Arès R. , Ruediger A.
Published: October 2016

Using apertureless scanning near-field optical microscopy to map refractive index variations, we study the phase separation in AlGaNAs alloys.
The synergistic effects of carbon coating and micropore structure on the microwave absorption properties of Co/CoO nanoparticles
Authors: Xie Xiubo , Pang Yu , Kikuchi Hiroaki , Liu Tong
Published: October 2016

Microporous Co/CoO/C nanoparticles prepared by combining chemical dealloying and chemical vapor deposition methods exhibited high microwave absorption properties due to the synergistic effects of the carbon coating and the micropore structure on the impedance matching of the absorber.
A graphene-like Mg3N2monolayer: high stability, desirable direct band gap and promising carrier mobility
Authors: Liu Peng-Fei , Zhou Liujiang , Frauenheim Thomas , Wu Li-Ming
Published: October 2016

A novel two-dimensional material, g-Mg3N2, exhibits an intrinsic direct band gap of 1.86 eV, outstanding stability (2000 K) and a high carrier mobility of up to 103cm2V−1s−1which is larger than that of MoS2and close to that of few-layer phosphorene.
The selective activation of a C–F bond with an auxiliary strong Lewis acid: a method to change the activation preference of C–F and C–H bonds
Authors: Wang Lin , Sun Hongjian , Li Xiaoyan , Fuhr Olaf , Fenske Dieter
Published: October 2016

Selective activations of C–F bond in substituted (2,6-difluorophenyl)phenylimines by Fe(PMe3)4 with an auxiliary strong Lewis acid were explored.
AXII4XIII5Te12 (A = Rb, Cs; XII = Mn, Zn, Cd; XIII = Ga, In): quaternary semiconducting tellurides with very low thermal conductivities
Authors: Lin Hua , Chen Hong , Zheng Yu-Jun , Yu Ju-Song , Wu Li-Ming
Published: October 2016

Three-dimensional diamond-like framework tellurides AXII4XIII5Te12 with very low thermal conductivities are reported for the first time.
DNA biosensor combining single-wavelength colorimetry and a digital lock-in amplifier within a smartphone
Authors: Wu Tzu-Heng , Chang Chia-Chen , Vaillant Julien , Bruyant Aurélien , Lin Chii-Wann
Published: October 2016

Smartphone camera based gold nanoparticle colorimetry (SCB-AuNP colorimetry) has shown good potential for point-of-care applications.
Synthesis, luminescence, and electrochemical studies of tetra- and octanuclear ruthenium(ii) complexes of tolylterpyridine appended calixarenes
Authors: Senthan Selvam Amudhan , Alexander Vedamanickam
Published: October 2016

Tetra- and octanuclear ruthenium(ii) complexes of tolylterpyridine appended calixarenes are synthesized and their luminescence and electrochemical properties are investigated.
Highly regioselective synthesis of 4-tosylthiomorpholine via intramolecular cyclization of N-tethered thioalkenols
Authors: Saikia Anil K. , Deka Manash J. , Borthakur Upasana
Published: October 2016

A one-pot, metal-free procedure has been developed for the synthesis of 4-tosylthiomorpholine from N-tethered thioalkenols via bromination, cyclization and subsequent elimination reaction in good yields. The reaction is highly regioselective.
An unexpected route to aldehyde-decorated single-chain nanoparticles from azides
Authors: González-Burgos Marina , Alegría Angel , Arbe Arantxa , Colmenero Juan , Pomposo José A.
Published: October 2016

A new route towards the straightforward synthesis of aldehyde-decorated ultrafine single-chain nanoparticles from azides is described.
Multiple polymerization – formation of hybrid materials consisting of two or more polymers from one monomer
Authors: Ebert T. , Wollbrink A. , Seifert A. , John R. , Spange S.
Published: October 2016

The synthesis of hybrid materials consisting of three different components from only one monomer is reported for the first time.
Fluorescent gold nanoparticles with chain-end grafted RAFT copolymers: influence of the polymer molecular weight and type of chromophore
Authors: Cepraga Cristina , Favier Arnaud , Lerouge Frédéric , Alcouffe Pierre , Chamignon Cécile , Lanoë Pierre-Henri , Monnereau Cyrille , Marotte Sophie , Ben Daoud Edna , Marvel Jacqueline , Leverrier Yann , Andraud Chantal , Parola Stéphane , Charreyre Marie-Thérèse
Published: October 2016

Fluorescence of gold nanoparticles functionalized with chain-end grafted RAFT copolymers increases with polymer corona thickness.
Preparation and electrical properties of a copper-conductive polymer hybrid nanostructure
Authors: Hassanien Reda , Almaky Mahdi M. , Houlton Andrew , Horrocks Benjamin R.
Published: October 2016

Conductive copper–polymer hybrid nanowires prepared by templating on DNA.
Probing thermal expansion coefficients of monolayers using surface enhanced Raman scattering
Authors: Zhang Duan , Wu Ye-Cun , Yang Mei , Liu Xiao , Coileáin Cormac Ó , Xu Hongjun , Abid Mourad , Abid Mohamed , Wang Jing-Jing , Shvets Igor V. , Liu Haonan , Wang Zhi , Yin Hongxing , Liu Huajun , Chun Byong Sun , Zhang Xiangdong , Wu Han-Chun
Published: October 2016

A non-destructive method has been proposed to probe thermal expansion coefficients of the monolayer materials using surface-enhanced Raman spectroscopy.
Cellulose nanofibril reinforced silica aerogels: optimization of the preparation process evaluated by a response surface methodology
Authors: Fu Jingjing , He Chunxia , Huang Jingda , Chen Zhilin , Wang Siqun
Published: October 2016

CNF–silica composite aerogels with reinforced mechanical properties were prepared under an ambient pressure drying method and optimized by a response surface methodology.
Facile synthesis of flower-like hierarchical NiCo2O4 microspheres as high-performance cathode materials for Li–O2 batteries
Authors: Wang Liangjun , Zhu Ting , Lyu Zhiyang , Zhang Jian , Gong Lili , Xiao Shuning , Liu Jia , Dong Wenhao , Cui Xinhang , Ho Ghim Wei , Chen Wei
Published: October 2016

The Li–O2 battery with flower-like hierarchical NiCo2O4 microspheres cathode exhibits a low discharge/charge voltage gap of 0.86 V, much lower than previously reported results for NiCo2O4.
Ultraviolet-induced polymerization of superabsorbent composites based on sodium humate and its urea release behavior
Authors: Liu Lan , Sawut Amatjan , Abliz Shawket , Nurulla Ismayil , Dolat Banugul , Yimit Mamatjan
Published: October 2016

This study was carried out to develop a superabsorbent composite for agriculture application, which is based on acrylic acid and sodium humate and prepared by ultraviolet-induced polymerization in the presence of crosslinker and composite initiator.
Na9Sb(Ge2Q6)2(Q = S, Se): two new antimony(iii) quaternary chalcogenides with ethane-like [Ge2Q6]6−ligands
Authors: Wu Xiaowen , Hu Yi , Pan Hui , Su Zhi
Published: October 2016

The changing character from different orientations of M–M bonds (M = Si, Ge) in quaternary chalcogenides was systematically studied.
Hollow mesoporous Gd2O3:Eu3+ spheres with enhanced luminescence and their drug releasing behavior
Authors: Liu Houqi , Liu Jingjing
Published: October 2016

Hollow mesoporous nanospheres Gd2O3:Eu3+ could be well fabricated by CCPS templates, which exhibited a durable drug release property.
A silver coordination cage assembled from [Ag2(bis(isoxazolyl))3]: DFT approach to the binding forces within the host–guest interactions
Authors: Guajardo-Maturana Raúl , Zarate Ximena , Claveria-Cadiz Francisca , Schott Eduardo
Published: October 2016

The storage and detection of different types of molecules using porous materials such as metal–organic frameworks (MOFs) have currently become an area of interest in chemistry.
Acetals from primary alcohols with the use of tridentate proton responsive phosphinepyridonate iridium catalysts
Authors: Sahoo A. R. , Jiang F. , Bruneau C. , Sharma G. V. M. , Suresh S. , Achard M.
Published: October 2016

The association of the new phosphinepyridonate ligands along with an iridium metallic precursor resulted in the selective acetalization of various primary alcohols via a formal dehydrogenative coupling reaction.
Fabrication of sponge-like α-Ni(OH)2on styrene–acrylonitrile copolymer (SAN)-derived carbon spheres as electrode materials for supercapacitor application
Authors: Mao Zemin , Zhou Yingjie , Wang Zhoulu , Yang Zhengkai , Liu Xiang
Published: October 2016

Styrene–acrylonitrile copolymer particles (SANPs) were synthesized through dispersion polymerization.
Fault detection filter design for switched systems with quantisation effects and packet dropout
Authors: Li Jian , H. Park Ju , Ye Dan
Published: October 2016

The problem of fault detection for switched systems with quantisation effects and packet dropout is presented in this study. A dynamic quantiser is introduced, which is composed of a dynamic scaling and a static quantiser. Since a novel switched system is modelled according to packet dropout, a switching strategy which combines average dwell time switching with event‐driven switching is proposed. The systems performance and the relationship between the switching signal and the packet dropout rate are simultaneously developed. Furthermore, sufficient conditions for the existence of fault detection filters are given in the framework of linear matrix inequality, and the filter gains and the quantiser range are derived by a convex optimised method. Finally, two illustrative examples demonstrate the effectiveness of the proposed method.
Fault‐tolerant control with control allocation for linear time varying systems: an output integral sliding mode approach
Authors: Galván‐Guerra Rosalba , Liu Xinyi , Laghrouche Salah , Fridman Leonid , Wack Maxime
Published: October 2016

A fault‐tolerant control scheme with a fixed control allocation strategy for linear time varying systems is proposed. The effects of the faults in the critical control channels are compensated theoretically exactly and the remaining effects are minimised by using an output integral sliding mode technique. Both aspects are achieved right after the initial time by using only output information. This approach allows dealing with total failures in some actuators under the assumption of redundancy. The effectiveness of the proposed scheme considering time varying faults is validated by computer simulations.
Distributed state estimation, fault detection and isolation filter design for heterogeneous multi‐agent linear parameter‐varying systems
Authors: Chadli Mohammed , Davoodi Mohammadreza , Meskin Nader
Published: October 2016

In this study, the authors present a new approach for the design of distributed state estimation and fault detection and isolation (FDI) filters for a class of linear parameter‐varying multi‐agent systems, where the state‐space representations of the agents are not identical. The developed formulation for the FDI offers a distributed filter design method, in which each agent uses sensor measurements both locally and from the neighbouring agents. Each FDI filter is in the ‘unknown input observer’ form which are designed so that their outputs, i.e. residual signals, are: (i) robust with respect to the external disturbance inputs and (ii) sensitive with respect to the fault signals. Moreover, it is shown that using the proposed methodology each agent is able to estimate not only its own states, but also states of its nearest neighbours in the presence of external disturbances and faults. Finally, a numerical example is given to illustrate the efficacy of the main results of the paper.
Stabilisation for a class of switched nonlinear systems and its application to aero‐engines
Authors: Lou Zhi‐E. , Zhao Jun
Published: October 2016

The stabilisation problem of a more general switched non‐linear system originated from the aero‐engine control systems is investigated under an average dwell‐time approach. First, a procedure of choosing coordinates transformations for individual subsystems is presented. Through these coordinates transformations, the original subsystems are transformed into their non‐linear normal forms, respectively, based on which the state feedback controllers and the Lyapunov functions for subsystems are obtained through a constructive design method. However, each subsystem and its own Lyapunov function are expressed in individual coordinates and a common coordinates transformation cannot be obtained, which makes the design of a switching law extremely difficult. The authors overcome this difficulty to construct a switching law with average dwell time which can guarantee asymptotic stability of the closed‐loop switched system. Finally, the proposed switched controller is applied to a switched model of turbofan engine, and simulation results show the feasibility and validity of the developed controller.
Structural difference histogram representation for texture image classification
Authors: Feng Jinwang , Liu Xinliang , Dong Yongsheng , Liang Lingfei , Pu Jiexin
Published: October 2016

Local binary pattern (LBP) is a frequently‐used texture descriptor. Lots of LBP‐variants have been proposed to improve its performance of representing textures. However, most of them ignore the global and neighbour‐difference information of an image texture. In this study, the authors propose a structural difference histogram representation by fusing the segmented structure pattern (SSP), the refined LBP (RLBP) and the neighbour‐difference pattern (NDP) for texture classification. Particularly, the segmented structure, which contains the global contour information of an image texture, is first constructed to compute its SSP histogram feature. Simultaneously, the RLBP is defined to represent the local texture information. Furthermore, the NDP is presented to describe differences between neighbours of a centre pixel in the local patch of texture images. Experimental results on Brodatz and Columbia‐Utrecht reflectance databases indicate that the proposed method can achieve the satisfactory classification accuracy compared with several representative methods.
Conductance quantization in an AgInSbTe-based memristor at nanosecond scale
Authors: Jiang L. , Xu L. , Chen J. W. , Yan P. , Xue K. H. , Sun H. J. , Miao X. S.
Published: October 2016

Quantized conductance was observed in a cation-migration-based memristor with the structure of Ag/AgInSbTe(AIST)/Ta. The conductance of the memristor exhibits stepwise increases in units of single quantum conductance (77.5 μS), which is attributed to the formation of a metal filament with an atomic contact of different integer multiples. We designed a high speed circuit to conduct the pulse measurement. The quantized conductance can be obtained by applying voltage pulses in intervals as fast as 3 ns with constant amplitude. Considering that the quantized conductance can be modulated by different pulse widths, our results suggest that the AIST-based memristor is a robust candidate for multi-level data storage and neuromorphic computing systems.
The microscopic structure of cold aqueous methanol mixtures
Authors: Požar Martina , Kerasidou Ariadni , Lovrinčević Bernarda , Zoranić Larisa , Mijaković Marijana , Primorac Tomislav , Sokolić Franjo , Teboul Victor , Perera Aurélien
Published: October 2016

The evolution of the micro-segregated structure of aqueous methanol mixtures, in the temperature range 300 K-120 K, is studied with computer simulations, from the static structural point of view. The structural heterogeneity of water is reinforced at lower temperatures, as witnessed by a pre-peak in the oxygen-oxygen structure factor. Water tends to form predominantly chain-like clusters at lower temperatures and smaller concentrations. Methanol domains have essentially the same chain-like cluster structure as the pure liquid at high concentrations and becomes monomeric at smaller ones. Concentration fluctuations decrease with temperature, leading to quasi-ideal Kirkwood-Buff integrals, despite the enhanced molecular interactions, which we interpret as the signature of non-interacting segregated water and methanol clusters. This study throws a new light on the nature of the micro-heterogeneous structure of this mixture: the domain segregation is essentially based on the appearance of linear water clusters, unlike other alcohol aqueous mixtures, such as with propanol or butanol, where the water domains are more bulky.
Accurate and efficient calculation of excitation energies with the active-space particle-particle random phase approximation
Authors: Zhang Du , Yang Weitao
Published: October 2016

An efficient method for calculating excitation energies based on the particle-particle random phase approximation (ppRPA) is presented. Neglecting the contributions from the high-lying virtual states and the low-lying core states leads to the significantly smaller active-space ppRPA matrix while keeping the error to within 0.05 eV from the corresponding full ppRPA excitation energies. The resulting computational cost is significantly reduced and becomes less than the construction of the non-local Fock exchange potential matrix in the self-consistent-field (SCF) procedure. With only a modest number of active orbitals, the original ppRPA singlet-triplet (ST) gaps as well as the low-lying single and double excitation energies can be accurately reproduced at much reduced computational costs, up to 100 times faster than the iterative Davidson diagonalization of the original full ppRPA matrix. For high-lying Rydberg excitations where the Davidson algorithm fails, the computational savings of active-space ppRPA with respect to the direct diagonalization is even more dramatic. The virtues of the underlying full ppRPA combined with the significantly lower computational cost of the active-space approach will significantly expand the applicability of the ppRPA method to calculate excitation energies at a cost of O(K4), with a prefactor much smaller than a single SCF Hartree-Fock (HF)/hybrid functional calculation, thus opening up new possibilities for the quantum mechanical study of excited state electronic structure of large systems.
Radiative heat transfer between nanoparticles: Shape dependence and three-body effect
Authors: Ramezan Choubdar Omid , Nikbakht Moladad
Published: October 2016

We study the effect of particles' shape on the radiative heat transfer in a three-body system. It is found that the radiative heat flux between two nanoparticles in a three-body system can be tuned by the shape of the third particle. In particular, we show that the heat flux is very sensitive to the particle shapes, and slight mismatches of shapes result in either enhanced or suppressed heat flux.
Nonlinear dielectric and discharge properties of Pb0.94La0.04[(Zr0.56Sn0.44)0.84Ti0.16]O3 antiferroelectric ceramics
Authors: Xu Ran , Xu Zhuo , Feng Yujun , Wei Xiaoyong , Tian Jingjing
Published: October 2016

Pb0.94La0.04[(Zr0.56Sn0.44)0.84Ti0.16]O3 antiferroelectric (AFE) ceramics were prepared by solid-state reaction and their nonlinear dielectric and discharge properties were studied. The releasable energy density and dielectric constant will increase sharply near 30 kV/cm due to the phase transition from antiferroelectric (AFE) to ferroelectric. The releasable energy density reaches maximum (0.50 J/cm3 under 40 kV/cm) at 30 °C and then decreases with temperature rise. The declination rate is less than 13% below 60 °C and will be remarkable at 160 °C due to the phase transition from AFE to paraelectric. The unique dielectric properties of AFE materials would result in special discharge properties. The discharge current density could be as high as 447 A/cm2, and the process finishes in sub-microsecond. The discharge current and hysteresis loop change very slightly after 10 000 charge–discharge cycles. The high energy density, fast discharge speed, and good fatigue resistance show the potential of obtained AFE ceramics for pulse power applications.
Bistable liquid crystal device fabricated via microscale liquid crystal alignment
Authors: Honma Michinori , Toyoshima Wataru , Nose Toshiaki
Published: October 2016

Bistable liquid crystal (LC) molecular orientation properties in micropatterned LC cells were investigated experimentally and theoretically. When an LC cell was heated to the phase-transition temperature and then cooled, an LC orientation with ±π/2-twist domains (±π/2-twist mode) was obtained. Furthermore, a different LC orientation with ±π-twist domains (±π-twist mode) was observed when a 10-V potential was applied across a sample LC cell. Both orientation states were stably retained over a long period. Herein, cross-sectional LC orientation models in the ±π/2- and ±π-twist modes are proposed to explain the generation and behavior of two different disclination lines. The total energies within one period in the ±π/2- and ±π-twist modes (F±π/2 and F±π, respectively) were estimated theoretically. These energies were found to depend on the LC layer thickness and to cross over at a certain thickness; this indicates that F±π is equal to F±π/2 at this equilibrium thickness. The best temporal stability is likely attained at this equilibrium thickness. We demonstrated a bistable color-switching device by combining a full-wave plate and crossed polarizers. When these optical components were configured properly, stable bistable switching between two colors was achieved.
Experimental evidence of harmful exciton dissociation at MoO3/CuPc interface in OPV
Authors: Yu A. R. , Yi R. C. , Zhang J. W. , Qin J. J. , Yu H. M. , Tang Y. J. , Shi R. C. , Hou X. Y.
Published: October 2016

Organic photovoltaics (OPVs) with three types of double anode buffer layers (DABLs), i.e., 4.5 nm hole-transport material 4,4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl layer, 1 nm electron-transport material Bphen, and 1 nm typical insulator LiF layer, respectively, deposited onto 10 nm MoO3 layer, were fabricated. All these three DABLs can improve the efficiency of CuPc/C60 based planar heterojunction OPV, especially with about 10% enhancement of short-circuit current (ISC). Based on the external quantum efficiency (EQE) and transient photovoltage (TPV) measurements, a mechanism of depressing harmful exciton dissociation at the MoO3/CuPc interface has been proposed. This harmful dissociation results in exciton loss within the CuPc layer, while a proper ultrathin layer inserted at MoO3/CuPc interface can effectively depress the dissociation and thus improve the total photocurrent.
Flexible bottom-gate graphene transistors on Parylene C substrate and the effect of current annealing
Authors: Park Dong-Wook , Kim Hyungsoo , Bong Jihye , Mikael Solomon , Kim Tong June , Williams Justin C. , Ma Zhenqiang
Published: October 2016

Flexible graphene transistors built on a biocompatible Parylene C substrate would enable active circuitry to be integrated into flexible implantable biomedical devices. An annealing method to improve the performance of a flexible transistor without damaging the flexible substrate is also desirable. Here, we present a fabrication method of a flexible graphene transistor with a bottom-gate coplanar structure on a Parylene C substrate. Also, a current annealing method and its effect on the device performance have been studied. The localized heat generated by the current annealing method improves the drain current, which is attributed to the decreased contact resistance between graphene and S/D electrodes. A maximum current annealing power in the Parylene C-based graphene transistor has been extracted to provide a guideline for an appropriate current annealing. The fabricated flexible graphene transistor shows a field-effect mobility, maximum transconductance, and a Ion/Ioff ratio of 533.5 cm2/V s, 58.1 μS, and 1.76, respectively. The low temperature process and the current annealing method presented here would be useful to fabricate two-dimensional materials-based flexible electronics.
Enhanced indistinguishability of in-plane single photons by resonance fluorescence on an integrated quantum dot
Authors: Kalliakos Sokratis , Brody Yarden , Bennett Anthony J. , Ellis David J. P. , Skiba-Szymanska Joanna , Farrer Ian , Griffiths Jonathan P. , Ritchie David A. , Shields Andrew J.
Published: October 2016

Integrated quantum light sources in photonic circuits are envisaged as the building blocks of future on-chip architectures for quantum logic operations. While semiconductor quantum dots have been proven to be the highly efficient emitters of quantum light, their interaction with the host material induces spectral decoherence, which decreases the indistinguishability of the emitted photons and limits their functionality. Here, we show that the indistinguishability of in-plane photons can be greatly enhanced by performing resonance fluorescence on a quantum dot coupled to a photonic crystal waveguide. We find that the resonant optical excitation of an exciton state induces an increase in the emitted single-photon coherence by a factor of 15. Two-photon interference experiments reveal a visibility of 0.80 ± 0.03, which is in good agreement with our theoretical model. Combined with the high in-plane light-injection efficiency of photonic crystal waveguides, our results pave the way for the use of this system for the on-chip generation and transmission of highly indistinguishable photons.
Diet of two fossorial herbivores in a seasonally snow-covered environment
Authors: Green K. , Davis N. E. , Robinson W. A.
Published: October 2016

To understand the recent elevational range expansion of European rabbits (Oryctolagus cuniculus) with declining snow cover and earlier snow thaw we examined their diet in relation to that of long-term residents, common wombats (Vombatus ursinus). The colonisation of eastern Australia by rabbits was effectively completed by 1910 when they reached an elevation of 1500 m (the winter snowline). Rabbits began to penetrate higher elevations only from the 1970s in association with anthropogenic habitat modification. Since 2011, rabbits have occupied elevations to the alpine treeline (~1850 m) throughout the year without the ameliorating presence of infrastructure or anthropogenically modified vegetation. Rabbits and wombats are both grazers preferring grasses (largely inaccessible beneath winter snow) and are spatially restricted in their foraging by their need to return to their burrows. Wombats used a much wider foraging range, enabling them to select preferred food. Rabbits, with a much smaller range, were constrained in their choice of forage mainly to plants that projected above the snow. Unexpectedly, rabbits fed intensively on leaves of eucalypts, food not typically consumed in substantial quantities by this species. These leaves, on stems regenerating after fire, will diminish in availability as stems mature, possibly halting the range expansion of rabbits.
Genetic analysis of docility score of Australian Angus and Limousin cattle
Authors: Walkom S. F. , Jeyaruban M. G. , Tier B. , Johnston D. J.
Published: October 2016

The temperament of cattle is believed to affect the profitability of the herd through impacting production costs, meat quality, reproduction, maternal behaviour and the welfare of the animals and their handlers. As part of the national beef cattle genetic evaluation in Australia by BREEDPLAN, 50 935 Angus and 50 930 Limousin calves were scored by seedstock producers for temperament using docility score. Docility score is a subjective score of the animal’s response to being restrained and isolated within a crush, at weaning, and is scored on a scale from 1 to 5 with 1 representing the quiet and 5 the extremely nervous or anxious calves. Genetic parameters for docility score were estimated using a threshold animal model with four thresholds (five categories) from a Bayesian analysis carried out using Gibbs sampling in THRGIBBS1F90 with post-Gibbs analysis in POSTGIBBSF90. The heritability of docility score on the observed scale was 0.21 and 0.39 in Angus and Limousin, respectively. Since the release of the docility breeding value to the Australian Limousin population there has been a favourable trend within the national herd towards more docile cattle. Weak but favourable genetic correlations between docility score and the production traits indicates that docility score is largely independent of these traits and that selection to improve temperament can occur without having an adverse effect on growth, fat, muscle and reproduction.
Floristics, dominance and diversity within the threatened Themeda grassy headlands of the North Coast Bioregion of New South Wales
Authors: Hunter John T. , Hunter Vanessa H.
Published: October 2016

We surveyed subtropical closed tussock grasslands on headlands within the North Coast Bioregion of New South Wales. The aims of the investigation were to provide baseline data on this listed threatened community. Additionally, we tested the effects of macropod grazing and biomass changes on assemblages. In total, 117 full floristic survey plots were placed within extant natural grassland occurrences on 16 headlands. Data collected included the percentage cover and frequency of each species. In addition, we ranked the three species contributing most to overall biomass. Analysis of the full floristic cover data (percentage cover) was performed using the Kulzynski association measure and Unweighted Pair Group Arithmetic Averaging fusion strategy. Further analysis was performed using constrained and unconstrained ordinations and Generalised Additive Modelling using species frequency data and explanatory variables including overall, and proportional species biomass, and macropod grazing impact. Seven distinct grassland assemblages were derived, of which three were Themeda dominated. Concentrating on the Themeda-dominated assemblages, it was found that increasing biomass depth and a reduction in macropod grazing impact were associated with a reduction in plot species richness and diversity and trait richness and diversity. These changes were associated with a shift in floristic assemblage identity. All three Themeda assemblages are likely to provide a unique combination of functional resources and all should be maintained in order to promote landscape diversity. We predict that use of frequent fire is likely to cause homogenisation (reduced landscape richness) and loss of important components including listed threatened taxa.
Directional amorphization of boron carbide subjected to laser shock compression
Authors: Zhao Shiteng , Kad Bimal , Remington Bruce A. , LaSalvia Jerry C. , Wehrenberg Christopher E. , Behler Kristopher D. , Meyers Marc A.
Published: October 2016

Significance

When crystalline solids are stressed quasi-statically, dislocation slip, twinning, and phase transformations are the predominant mechanisms to dissipate the imparted elastic energy. Under shock, high hydrostatic and shear stresses promptly build up at the shock front, favoring fast energy dissipation mechanisms. Amorphization, which may only involve localized atomic arrangements, is therefore an additional potential candidate. Shock-induced amorphization has now been reported in various materials and hence should be incorporated as a deformation/damage mechanism of crystals subjected to high-strain-rate loading.
Recognition of enzymes lacking bound cofactor by protein quality control
Authors: Martínez-Limón Adrián , Alriquet Marion , Lang Wei-Han , Calloni Giulia , Wittig Ilka , Vabulas R. Martin
Published: October 2016

Significance

Newly synthetized enzymes must fold correctly and associate with cofactors to reach their functional state. Mutations often interfere with the structural and functional maturation and lead to unstable proteins. Here we demonstrate that cofactor deprivation caused by vitamin B2 deficiency results in the destabilization of a significant fraction of flavin-containing enzymes, even if they have wild-type sequences. The accumulation of conditionally unstable proteins would overload cellular protein degradation systems; consequently, these proteins would contribute to amyloidogenesis and protein aggregation disorders. Because nutritional deficits often develop in aging organisms, this study provides an additional, protein stability-based explanation of the connection between vitamin supplies and healthy aging.
Listeners learn phonotactic patterns conditioned on suprasegmental cues
Authors: White Katherine S. , Chambers Kyle E. , Miller Zachary , Jethava Vibhuti
Published: October 2016

Language learners are sensitive to phonotactic patterns from an early age, and can acquire both simple and 2nd-order positional restrictions contingent on segment identity (e.g., /f/ is an onset with /æ/but a coda with /ɪ/). The present study explored the learning of phonototactic patterns conditioned on a suprasegmental cue: lexical stress. Adults first heard non-words in which trochaic and iambic items had different consonant restrictions. In Experiment 1, participants trained with phonotactic patterns involving natural classes of consonants later falsely recognized novel items that were consistent with the training patterns (legal items), demonstrating that they had learned the stress-conditioned phonotactic patterns. However, this was only true for iambic items. In Experiment 2, participants completed a forced-choice test between novel legal and novel illegal items and were again successful only for the iambic items. Experiment 3 demonstrated learning for trochaic items when they were presented alone. Finally, in Experiment 4, in which the training phase was lengthened, participants successfully learned both sets of phonotactic patterns. These experiments provide evidence that learners consider more global phonological properties in the computation of phonotactic patterns, and that learners can acquire multiple sets of patterns simultaneously, even contradictory ones.
Own-age biases in adults’ and children’s joint attention: Biased face prioritization, but not gaze following!
Authors: Freebody Susannah , Kuhn Gustav
Published: October 2016

Previous studies have reported own-age biases in younger and older adults in gaze following. We investigated own-age biases in social attentional processes between adults and children by focusing on two aspects of the joint attention process; the extent to which people attend towards an individual’s face, and the extent to which they fixate objects that are looked at by this person (i.e., gaze following). Participants viewed images that always contained a child and an adult who either looked towards each other or each looked at objects located to their side. Observers consistently, and rapidly fixated the actor’s faces, though the children were faster to fixate the child’s face than the adult’s faces, whilst the adults were faster to fixate on the adult’s face than the child’s face. The children also spent significantly more time fixating the child’s face than the adult’s face, and the opposite pattern of results was found for the adults. Whilst both adults and children prioritized objects when they were looked at by the actor, both groups showed equivalent levels of gaze following, and there was no own-age bias for gaze following. Our results show an own-age bias for prioritizing faces, but not gaze following.
Neutrophil mechanotransduction: A GEF to sense fluid shear stress
Authors: Niethammer Philipp
Published: October 2016

Forces deriving from blood flow shear modulate vascular adherence and transendothelial migration of leukocytes into inflamed tissues, but the mechanisms by which shear is sensed are unclear. In this issue, Fine et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201603109) identify the guanosine nucleotide exchange factor GEF-H1 as critical for shear stress–induced transendothelial neutrophil migration.