bluuebunny/crossref_metadata_2025 huggingface dataset:
Programmed Degradation of DNA Multilayer Films
Authors: Lee Lillian , Johnston Angus P. R. , Caruso Frank
Published: March 2014

The design and assembly of DNA multilayer films with programmable degradation properties are reported. The nanostructured DNA films are assembled through the layer‐by‐layer (LbL) assembly technique and can be programmed to degrade by subsequently introducing DNA strands of specific sequences. The strands preferentially hybridize to the building blocks that stabilize the film structure, causing the film to rearrange and degrade. The rate of degradation is influenced by both the availability and accessibility of the complementary DNA binding sites within the film, as well as the degree of crosslinking within the film. Similar results are obtained for DNA multilayer films assembled on planar and particle supports. This approach offers an avenue to tailor degradability features into DNA‐based materials that may find application in the biosciences, in areas such as biosensing and drug delivery.
High Responsivity and Gate Tunable Graphene‐MoS2 Hybrid Phototransistor
Authors: Xu Hua , Wu Juanxia , Feng Qingliang , Mao Nannan , Wang Chunming , Zhang Jin
Published: March 2014

A 2D atomic‐layer‐thickness phototransistor based on a graphene‐MoS2 bybrid device is constructed with a photoresponse much larger than that of individual graphene or MoS2 based phototransistors. Strong and selective light absorption in the MoS2 layer creates electric charges that are transferred to graphene layers derived by a build‐in electrical field, where they recirculate many times due to the high carrier mobility of graphene. Gate tunable Fermi level in graphene layer allows the responsivity of this hybrid phototransistor to be continuously tuned from 0 to about 104 mA/W by the gate voltage. Furthermore, large scale, flexible, and transparent 2D phototransistors with high responsivity are constructed from the CVD‐grown graphene and MoS2 flakes. The high responsivity, gate‐tunable sensitivity, wavelength selectivity, and compatibility with current circuit technologies of this type device give it great potential for future application in integrated nano‐optoelectronic systems.
Adaptive Projection‐Based Interpolation as a Pre‐Processing Tool in the Finite Element Workflow for Elasticity Simulations of the Dual Phase Microstructures
Authors: Sieniek Marcin , Paszyński Maciej , Madej Łukasz , Goik Damian
Published: March 2014

An improvement to the workflow used in modeling boundary‐value problems in complex materials, which allows for reducing computational time by the factor of 5 while maintaining comparable quality of the solution is proposed in this paper. After formulating the main goals of the paper, a review of the state‐of‐the‐art techniques used for generating a digital material representation is presented. This is followed by a description of the procedure for solving boundary‐value problems and finding a representation of a given microstructure in a desired functional base. Finally, we showcase how to combine these techniques to obtain mentioned significant calculation speedup. Developed approach is validated during investigation of a selected case study, which is modeling of a linear elastic deformation of a dual phase ferritic–martensitic steel under thermal loading conditions.
Development of a phenotypic assay for characterisation of ethanologenic yeast strain sensitivity to inhibitors released from lignocellulosic feedstocks
Authors: Greetham D , Wimalasena T , Kerruish D W M , Brindley S , Ibbett R N , Linforth R L , Tucker G , Phister T G , Smart K A
Published: March 2014

Inhibitors released by the breakdown of plant cell walls prevent efficient conversion of sugar into ethanol. The aim of this study was to develop a fast and reliable inhibitor sensitivity assay for ethanologenic yeast strains. The assay comprised bespoke 96-well plates containing inhibitors in isolation or combination in a format that was compatible with the Phenotypic Microarray Omnilog reader (Biolog, hayward, CA, USA). A redox reporter within the assay permits analysis of inhibitor sensitivity in aerobic and/or anaerobic conditions. Results from the assay were verified using growth on spot plates and tolerance assays in which maintenance of viability was assessed. The assay allows for individual and synergistic effects of inhibitors to be determined. It was observed that the presence of both acetic and formic acid significantly inhibited the yeast strains assessed, although this impact could be partially mitigated by buffering to neutral pH. Scheffersomyces stipitis, Candida spp., and Pichia guilliermondii demonstrated increased sensitivity to short chain weak acids at concentrations typically present in lignocellulosic hydrolysates. S. cerevisiae exhibited robustness to short chain weak acids at these concentrations. However, S. stipitis, Candida spp., and P. guilliermondii displayed increased tolerance to HMF when compared to that observed for S. cerevisiae. The results demonstrate that the phenotypic microarray assay developed in the current study is a valuable tool that can be used to identify yeast strains with desirable resistance to inhibitory compounds found in lignocellulosic hydrolysates.
Definition of culture conditions for Arxula adeninivorans, a rational basis for studying heterologous gene expression in this dimorphic yeast
Authors: Stöckmann Christoph , Palmen Thomas G , Schroer Kirsten , Kunze Gotthard , Gellissen Gerd , Büchs Jochen
Published: March 2014

The yeast Arxula adeninivorans is considered to be a promising producer of recombinant proteins. However, growth characteristics are poorly investigated and no industrial process has been established yet. Though of vital interest for strain screening and production processes, rationally defined culture conditions remain to be developed. A cultivation system was evolved based on targeted sampling and mathematical analysis of rationally designed small-scale cultivations in shake flasks. The oxygen and carbon dioxide transfer rates were analyzed as conclusive online parameters. Oxygen limitation extended cultivation and led to ethanol formation in cultures supplied with glucose. Cultures were inhibited at pH-values below 2.8. The phosphorus demand was determined as 1.55 g phosphorus per 100 g cell dry weight. Synthetic SYN6 medium with 20 g glucose l−1 was optimized for cultivation in shake flasks by buffering at pH 6.4 with 140 mmol MES l−1. Optimized SYN6 medium and operating conditions provided non-limited cultivations without by-product formation. A maximal specific growth rate of 0.32 h−1 and short fermentations of 15 h were achieved. A pH optimum curve was derived from the oxygen transfer rates of differently buffered cultures, showing maximal growth between pH 2.8 and 6.5. Furthermore, it was shown that the applied medium and cultivation conditions were also suitable for non-limiting growth and product formation of a genetically modified A. adeninivorans strain expressing a heterologous phytase.
A conceptual framework for tackling knowable unknown unknowns in project management
Authors: Ramasesh Ranga V. , Browning Tyson R.
Published: March 2014

Understanding and dealing with the unknown is a major challenge in project management. An extensive body of knowledge—theory and technique—exists on the “known unknowns,” i.e., uncertainties which can be described probabilistically and addressed through the conventional techniques of risk management. Although some recent studies have addressed projects where the existence of unknown unknowns (unk unks) is readily apparent or may be assumed given the type of project—e.g., new product development or new process implementation—very little work has been reported with respect to projects in general on how a project manager might assess its vulnerability to unk unks. In this paper, we present a conceptual framework to deal with (i.e., recognize and reduce) knowable unk unks in project management. The framework is supported by insights from a variety of theories, case analyses, and experiences. In this framework, we first present a model of the key factors—relating to both project design and behavioral issues—that increase the likelihood of unk unks and a set of propositions linking these factors to unk unks. We then present a set of design and behavioral approaches that project managers could adopt to reduce knowable unk unks. Our framework fills a gap in the project management literature and makes a significant practical contribution: it helps project managers diagnose a project to recognize and reduce the likelihood of unk unks and thus deal more effectively with the otherwise unrecognized risks and opportunities.
Multi-oscillations of a bubble in a compressible liquid near a rigid boundary
Authors: Wang Qianxi
Published: March 2014

Bubble dynamics near a rigid boundary are associated with wide and important applications in cavitation erosion in many industrial systems and medical ultrasonics. This classical problem is revisited with the following two developments. Firstly, computational studies on the problem have commonly been based on an incompressible fluid model, but the compressible effects are essential in this phenomenon. Consequently, a bubble usually undergoes significantly damped oscillation in practice. In this paper this phenomenon will be modelled using weakly compressible theory and a modified boundary integral method for an axisymmetric configuration, which predicts the damped oscillation. Secondly, the computational studies so far have largely been concerned with the first cycle of oscillation. However, a bubble usually oscillates for a few cycles before it breaks into much smaller ones. Cavitation erosion may be associated with the recollapse phase when the bubble is initiated more than the maximum bubble radius away from the boundary. Both the first and second cycles of oscillation will be modelled. The toroidal bubble formed towards the end of the collapse phase is modelled using a vortex ring model. The repeated topological changes of the bubble are traced from a singly connected to a doubly connected form, and vice versa. This model considers the energy loss due to shock waves emitted at minimum bubble volumes during the beginning of the expansion phase and around the end of the collapse phase. It predicts damped oscillations, where both the maximum bubble radius and the oscillation period reduce significantly from the first to second cycles of oscillation. The damping of the bubble oscillation is alleviated by the existence of the rigid boundary and reduces with the standoff distance between them. Our computations correlate well with the experimental data (Philipp & Lauterborn,J. Fluid Mech., vol. 361, 1998, pp. 75–116) for both the first and second cycles of oscillation. We have successively reproduced the bubble ring in direct contact with the rigid boundary at the end of the second collapse phase, a phenomenon that was suggested to be one of the major causes of cavitation erosion by experimental studies.
The Captured Garden: The Political Ecology of Subsistence under Capitalism
Authors: Stoll Steven
Published: March 2014

Household subsistence food production did not disappear under capitalism; instead, it functioned within the circulation of capital. British lords and American mining company managers realized that the same practices that once resulted in autonomy for peasants and mountain-dwelling households could be absorbed, “captured,” to subsidize wages. This article considers the captured garden in two forms. The first resulted in capital accumulation, while the second sustained the unemployed without public assistance. Both appeared in West Virginia between the 1880s and the 1930s. Gardens moved into the coal camps, encouraged and compelled by the companies. During the Great Depression the Roosevelt administration established the Division of Subsistence Homesteads, combining gardens and factory wages as a relief program. Both forms illustrate the paradox of subsistence production under capitalism: A practice that for centuries created no surplus value could be made to do just that; an institution once the stronghold of the household could cause dependency and immiseration.
Who are the poor? Measuring wealth inequality to aid understanding of socioeconomic contexts for conservation: a case-study from the Solomon Islands
Authors: DAVIES TAMMY E. , PETTORELLI NATHALIE , CRESSWELL WILL , FAZEY IOAN R. A.
Published: March 2014

Understanding the local socioeconomic context is important for the design of appropriate conservation initiatives and associated monitoring strategies, especially in areas with high degrees of inequality, to ensure conservation interventions do not inadvertently further disadvantage vulnerable people. Typical assessments of wealth inequality in remote rural areas are constrained by limited engagement with a cash economy, complex family and tribal ties, and an absence of basic infrastructure. This paper presents a simple participatory approach to measure wealth inequality that does not predefine indicators, such as income or assets, but allows the local people choose the most appropriate indicators. A case study from the Solomon Islands revealed poor households in Kahua were characterized by fewer members, fewer members of working age, and fewer male members than wealthier households. The poor also owned fewer of the locally defined indicators of wealth that were collectively correlated with limited land tenure, and, consequently, conservation or development initiatives that are tied to land in Kahua will be less likely to assist the poorest. Adopting this participatory approach could improve the effectiveness of community-based conservation, through facilitating opportunities to explore local poverty and routes for alleviation.
Principal component analysis
Authors: Bro Rasmus , Smilde Age K.
Published: March 2014

Principal component analysis is one of the most important and powerful methods in chemometrics as well as in a wealth of other areas.
The microfluidic puzzle: chip-oriented rapid prototyping
Authors: Lim Jiseok , Maes Florine , Taly Valérie , Baret Jean-Christophe
Published: March 2014

We demonstrate a new concept for reconfigurable microfluidic devices from elementary functional units.
A facile and efficient synthesis of functionalized 4-oxo-2-(phenylimino)thiazolidin-5-ylideneacetate derivatives via a CuFe2O4 magnetic nanoparticles catalyzed regioselective pathway
Authors: Pal Gargi , Paul Sanjay , Das Asish R.
Published: March 2014

Nano-CuFe2O4 spinel has been found to exhibit strong catalytic activity in the cascade reaction involving 1,4-addition and intramolecular electrophilic cyclization in a perfectly regiocontrolled manner and a series of functionalized 4-oxo-2-(phenylimino)thiazolidin-5-ylideneacetate derivatives were generated successfully.
Spectroscopy of discrete vertically oriented single-crystals of n-type tetraazaterrylene: understanding the role of defects in molecular semiconductor photovoltaics
Authors: Wise A. J. , Zhang Y. , Fan J. , Wudl F. , Briseno A. L. , Barnes M. D.
Published: March 2014

Oriented single crystals of tetra-aza-terrylene (TAT), and photoluminescence of pristine and defect structures.
Urchin-like TiO2@C core–shell microspheres: coupled synthesis and lithium-ion battery applications
Authors: Liu Zhenyu , Liu Jing , Liu Junfeng , Wang Li , Zhang Guoxin , Sun Xiaoming
Published: March 2014

Carbon coated urchin-like TiO2 microspheres were prepared through coupled hydrolysis of titanium tetrachloride and catalyzed carbonization of glucose.
Warm white light generation from a single phase Dy3+ doped Mg2Al4Si5O18 phosphor for white UV-LEDs
Authors: Ci Zhipeng , Sun Qisheng , Qin Shengchun , Sun Mengxing , Jiang Xiaojing , Zhang Xudong , Wang Yuhua
Published: March 2014

A single phase white-emitting Mg2Al4Si5O18:Dy3+ phosphor was synthesized and the photoluminescence, energy-transfer mechanism and thermal properties are carefully investigated.
FRET-reporter nanoparticles to monitor redox-induced intracellular delivery of active compounds
Authors: Gulin-Sarfraz Tina , Sarfraz Jawad , Didem Şen Karaman Didem Şen Karaman , Zhang Jixi , Oetken-Lindholm Christina , Duchanoy Alain , Rosenholm Jessica M. , Abankwa Daniel
Published: March 2014

FRET-reporter particles for redox-induced release of active compounds in cells were developed. This particle system allowed following the intracellular cleavage of delivered compounds after particle internalization.
Detection of salient regions in crowded scenes
Authors: Lim M.K. , Chan C.S. , Monekosso D. , Remagnino P.
Published: March 2014

The increasing number of cameras and a handful of human operators to monitor the video inputs from hundreds of cameras leave the system ill equipped to fulfil the task of detecting anomalies. Thus, there is a dire need to automatically detect the regions that require immediate attention for more effective and proactive surveillance. A framework that utilises the temporal variations in the flow field of a crowd scene to automatically detect salient regions is proposed, while eliminating the need to have prior knowledge of the scene or training. The flow fields are deemed to be a dynamic system and adopt the stability theory of dynamic systems, to determine the motion dynamics within a given area. In this context, the salient regions refer to the areas with high motion dynamics, where the points in a particular region are unstable. The experimental results on public, crowd scenes have shown the effectiveness of the proposed method in detecting salient regions which correspond to an unstable flow, occlusions, bottlenecks, and entries and exits.
Compact helical antenna with small ground fed by spiral‐shaped microstrip line
Authors: Liu Longsheng , Li Yue , Zhang Zhijun , Feng Zhenghe
Published: March 2014

A compact helical antenna with a small ground is proposed for 5.2/5.8 GHz WLAN applications. The proposed antenna can be easily mounted in the space‐limited systems. Good impedance matching is achieved by a spiral‐shaped microstrip line feed structure. Relatively uniform current along the helix is observed owing to the travelling‐wave current on the feed structure, which contributes to high‐gain performance even with a small ground. The measured 3 dB axial ratio bandwidth and impedance bandwidth for S11 ≤ −10 dB overlap over 5–6 GHz, whereas the realised gain of about 13–14 dBic is achieved over the 5.2/5.8 GHz WLAN band.
Group delay measurement method based on narrow‐band spread spectrum signals
Authors: Xiao Zhi Bin , Liu Yingxiang , Tang Xiaomei , Zhu Xiang Wei , Wang Feixue
Published: March 2014

The group delay fluctuation of navigation equipment will cause signal distortion, thus bringing on ranging bias, and therfore needs to be measured and compensated. The vector network analyser method commonly adopted cannot satisfy high measuring accuracy and high frequency resolution at the same time; the higher the frequency resolution, the bigger the measuring error. To resolve this problem, a new group delay measurement method based on narrow‐band spread spectrum signals is proposed. Theoretical analysis and simulation results indicate that this method can implement high measuring accuracy with any frequency resolution, and the system bias of the method is much less than 0.1 ns.
Highly sensitive seesaw capacitive pressure sensor based on SOI wafer
Authors: Yang C.C. , Zhao Q. , Gao C.C. , Liu G.D. , Zhang Y.X. , Cui W.P. , Hao Y.L.
Published: March 2014

A novel microelectromechanical system capacitive pressure sensor with two wings, which amplify the mechanical deformation of the pressure sensing diaphragm and increase the sensor's sensitivity, is presented. This seesaw structure is available for both single and differential capacitive pressure sensors. To verify this design, a single capacitive pressure sensor is manufactured based on silicon on a insulator (SOI) wafer. The test result shows that this pressure sensor has a sensitivity of 7.75 fF/kPa.
Reconstruction method for pulse position modulation‐ultra wideband communication signal based on compressed sensing
Authors: Weidong Wang , Jun‐an Yang , Haibo Yin , Shehui Wang
Published: March 2014

Pulse position modulation‐ultra wideband (PPM‐UWB) communication adopts ultra narrow pulse as the transmitted signal. Owing to the low‐power spectral density and ultra wide bandwidth, it is difficult to detect and sample PPM‐UWB signal directly. There are already some researches on using compressed sensing (CS) theory for UWB communication with lower sampling speed. However, these methods take the sparseness of pulse position or transmission channel into account separately and they are unfit for practical communication. To solve these problems, a dual‐sparse reconstruction method is proposed in this paper to process PPM‐UWB communication signal based on CS theory. Proposed method designs the target signal which needed to be reconstructed as a dual‐sparse vector. This vector combines the sparseness of PPM pulse position and UWB channel multi‐paths simultaneously, hence it has dual sparseness. The information code can be demodulated from reconstructed dual‐sparse vector directly by using energy detection method. Extensive numerical simulations demonstrate the validity and applicability of proposed method.
Peak‐to‐average power ratio reduction in Alamouti multi‐input–multi‐output orthogonal frequency division multiplexing systems without side information using phase offset based‐partial transmit sequence scheme
Authors: Jiang Tao , Ni Chunxing , Guan Lili , Qi Qi
Published: March 2014

In this study, a novel phase offset‐based partial transmit sequence (PTS) scheme is proposed to reduce the peak‐to‐average power ratio (PAPR) in Alamouti coded multi‐input–multi‐output orthogonal frequency division multiplexing systems, and its key idea is that different phase rotation sequences are multiplied by their corresponding phase offsets at the transmitter. Moreover, a minimum Euclidean distance decoder is proposed to recover the phase rotation sequences at the receiver. The theoretical analysis and simulation results show that the proposed PTS scheme could offer good performances of both the bit error rate and the PAPR reduction without transmitting the side information, resulting in the increase of the data rate.
Cooperation in wireless networks: a game‐theoretic framework with reinforcement learning
Authors: Baidas Mohammed Wael
Published: March 2014

A game‐theoretic framework based on the iterated prisoner's dilemma (IPD) is proposed to model the repeated dynamic interactions of multiple source nodes when communicating with multiple destinations in an ad hoc wireless network. In such networks where nodes are autonomous, selfish and not familiar with other nodes’ strategies, fully cooperative behaviours cannot be assumed. Therefore reinforcement learning is studied to relate the utility function of each source node to actions previously taken in order to learn a strategy that maximises their expected future reward. Particularly, a Q‐learning algorithm is proposed to allow network nodes to adapt to and play the IPD game against opponents with a variety of known and unknown strategies. Simulation results illustrate that the proposed Q‐learning algorithm allows network nodes to play optimally and achieve their maximum expected return values.
Simplified space vector modulation technique for seven‐level cascaded H‐bridge inverter
Authors: Ahmed Irfan , Borghate Vijay B.
Published: March 2014

A simplified space vector modulation (SVM) technique is proposed for the seven‐level cascaded H‐bridge (CHB) inverter. It is based on decomposing the seven‐level space vector hexagon into a number of two‐level space vector hexagons. The presented technique significantly reduces the calculation time and efforts involved in the SVM of a seven‐level inverter; without any loss in the output voltage magnitude or increase in the total harmonic distortion content. A further simplified technique is also presented in this study, which significantly reduces the complexity and effort involved in the seven‐level SVM. Simulation results for the seven‐level CHB inverter using the proposed techniques are presented. The results are compared with results using sinusoidal pulse‐width modulation (PWM) and third harmonic injection PWM to prove the validity of the proposed techniques. The proposed technique is perfectly general and can be applied to all types of multilevel inverters and extended to higher level inverters.
Electrical conductive Cu/glass fibre composites prepared by electroless plating
Authors: Zhang Zhiyi
Published: March 2014

A simple and efficient method has been developed to create an electrical conductive copper shell on glass fibres. Instead of regular formaldehyde, the preferable reducing capacity of hydrazine hydrate served as the reducing agent for copper plating. On this basic condition, the effect of the bath temperature, the Na3C6H5O7 ·2H2O and the NH3 ·H2O concentrations on the morphology and the conductivity of the Cu/glass fibre were explored. The morphology and the microstructure of the Cu/glass fibre particles were characterised by scanning electron microscopy, X‐ray diffractometer techniques and the electrical conductivity was detected with the four‐point probe method. The results showed that a compact and uniform copper layer was successfully deposited on the activated glass fibre, and the as‐synthesised Cu/glass fibre composites exhibited a face centred cubic crystal structure and presented excellent electrical conductivity where the volume resistivity was 8.62 × 10–4 Ω cm.
Tunneling magnetoresistance of perpendicular magnetic tunnel junction using L1 FePt electrodes on MgO/CrRu/TiN under-layers
Authors: Soo Kim Chang , Jung Jin-Won , Choi Dooho , Sahashi Masashi , Kryder Mark H.
Published: March 2014

A perpendicular magnetic tunnel junction (pMTJ) device was fabricated using L10 ordered FePt electrodes, which were deposited on MgO(8 nm)/CrRu(10 nm)/TiN(4 nm) under-layers. It was found that the MgO/CrRu/TiN under-layer helps lower the required FePt deposition temperature to below 400 °C, and provides a well-ordered bottom L10 FePt electrode with root-mean-square (RMS) surface roughness close to 0.4 nm. Magnetoresistance (MR) ratio and resistance-area (RA) were measured at room temperature by the current-in-plane tunneling (CIPT) method from a lithographically unpatterned PMTJ sample and 138% and 6.4 kΩ μm2 were obtained, respectively. A PMTJ test pattern, with a junction size of 80 × 40 μm2, was also fabricated and showed a MR ratio and RA product of 108% and 4 ∼ 6 kΩ μm2, respectively, in good agreement with the CIPT measurements.
Proton-bound dimers of nitrogen heterocyclic molecules: Substituent effects on the structures and binding energies of homodimers of diazine, triazine, and fluoropyridine
Authors: Attah Isaac K. , Platt Sean P. , Meot-Ner (Mautner) Michael , El-Shall M. S. , Aziz Saadullah G. , Alyoubi Abdulrahman O.
Published: March 2014

The bonding energies of proton-bound homodimers BH+B were measured by ion mobility equilibrium studies and calculated at the DFT B3LYP/6-311++G** level, for a series of nitrogen heterocyclic molecules (B) with electron-withdrawing in-ring N and on-ring F substituents. The binding energies (ΔH°dissoc) of the proton-bound dimers (BH+B) vary significantly, from 29.7 to 18.1 kcal/mol, decreasing linearly with decreasing the proton affinity of the monomer (B). This trend differs significantly from the constant binding energies of most homodimers of other organic nitrogen and oxygen bases. The experimentally measured ΔH°dissoc for (1,3-diazine)2H+, i.e., (pyrimidine)2H+ and (3-F-pyridine)2H+ are 22.7 and 23.0 kcal/mol, respectively. The measured ΔH°dissoc for the pyrimidine·+(3-F-pyridine) radical cation dimer (19.2 kcal/mol) is signifcantly lower than that of the proton-bound homodimers of pyrimidine and 3-F-pyridine, reflecting the stronger interaction in the ionic H-bond of the protonated dimers. The calculated binding energies for (1,2-diazine)2H+, (pyridine)2H+, (2-F-pyridine)2H+, (3-F-pyridine)2H+, (2,6-di-F-pyridine)2H+, (4-F-pyridine)2H+, (1,3-diazine)2H+, (1,4-diazine)2H+, (1,3,5-triazine)2H+, and (pentafluoropyridine)2H+ are 29.7, 24.9, 24.8, 23.3, 23.2, 23.0, 22.4, 21.9, 19.3, and 18.1 kcal/mol, respectively. The electron-withdrawing substituents form internal dipoles whose electrostatic interactions contribute to both the decreased proton affinities of (B) and the decreased binding energies of the protonated dimers BH+B. The bonding energies also vary with rotation about the hydrogen bond, and they decrease in rotamers where the internal dipoles of the components are aligned efficiently for inter-ring repulsion. For compounds substituted at the 3 or 4 (meta or para) positions, the lowest energy rotamers are T-shaped with the planes of the two rings rotated by 90° about the hydrogen bond, while the planar rotamers are weakened by repulsion between the ortho hydrogen atoms of the two rings. Conversely, in ortho-substituted (1,2-diazine)2H+ and (2-F-pyridine)2H+, attractive interactions between the ortho (C–H) hydrogen atoms of one ring and the electronegative ortho atoms (N or F) of the other ring are stabilizing, and increase the protonated dimer binding energies by up to 4 kcal/mol. In all of the dimers, rotation about the hydrogen bond can involve a 2–4 kcal/mol barrier due to the relative energies of the rotamers.
The area reactivity model of geminate recombination
Authors: Prüstel Thorsten , Meier-Schellersheim Martin
Published: March 2014

We investigate the reversible diffusion-influenced reaction of an isolated pair in the context of the area reactivity model that describes the reversible binding of a single molecule in the presence of a binding site in terms of a generalized version of the Feynman-Kac equation in two dimensions. We compute the corresponding exact Green's function in the Laplace domain for both the initially unbound and bound molecule. We discuss convolution relations that facilitate the calculation of the binding and survival probabilities. Furthermore, we calculate an exact analytical expression for the Green's function in the time domain by inverting the Laplace transform via the Bromwich contour integral and derive expressions for the binding and survival probability in the time domain as well. We numerically confirm the accuracy of the obtained expressions by propagating the generalized Feynman-Kac equation in the time domain. Our results should be useful for comparing the area reactivity model with the contact reactivity model.
Effect of ethanol-water mixture on the structure and dynamics of lysozyme: A fluorescence correlation spectroscopy study
Authors: Chattoraj Shyamtanu , Mandal Amit Kumar , Bhattacharyya Kankan
Published: March 2014

Effect of ethanol-water mixture on the hydrodynamic radius (rH) and conformational dynamics of lysozyme has been studied by circular dichroism, emission spectra, and fluorescence correlation spectroscopy. For this purpose, the protein lysozyme is covalently labeled near the active site with a fluorescent probe, alexa 488. The ethanol molecules are sequestered near the hydrophobic tryptophan residues as indicated by the blue shift of the emission maximum of tryptophan. It is observed that both size (rH) and time constant of conformational relaxation (τR) of lysozyme oscillate with increase in ethanol concentration. The rH of the protein fluctuates from 19 Å in the native state, to a minimum of 13 Å, and a maximum of 29 Å. It is proposed that the oscillating behavior arises from competition between mutual interaction among protein, ethanol, and water. The fluorescence intensity fluctuates because of quenching of the fluorescence of the probe (alexa) by the free amino group of certain residues (e.g., tryptophan). Rate of inter-conversion (folding dynamics) between the open (fluorescent) and closed (non-fluorescent) form has been determined and is found to exhibit similar oscillation with variation in ethanol content.
A multi-axis confocal rheoscope for studying shear flow of structured fluids
Authors: Lin Neil Y. C. , McCoy Jonathan H. , Cheng Xiang , Leahy Brian , Israelachvili Jacob N. , Cohen Itai
Published: March 2014

We present a new design for a confocal rheoscope that enables uniform uniaxial or biaxial shear. The design consists of two precisely positioned parallel plates with a gap that can be adjusted down to 2 ±0.1 μm, allowing for the exploration of confinement effects. By using our shear cell in conjunction with a biaxial force measurement device and a high-speed confocal microscope, we are able to measure the real-time biaxial stress while simultaneously imaging the material three-dimensional structure. We illustrate the importance of the instrument capabilities by discussing the applications of this instrument in current and future research topics in colloidal suspensions.
Controlling temperature in magnetic hyperthermia with low Curie temperature particles
Authors: Astefanoaei Iordana , Dumitru Ioan , Chiriac Horia , Stancu Alexandru
Published: March 2014

Hyperthermia induced by the heating of magnetic particles (MPs) in alternating magnetic field receives a considerable attention in cancer therapy. An interesting development in the studies dedicated to magnetically based hyperthermia is the possibility to control the temperature using MPs with selective magnetic absorption properties. This paper analyzes the temperature field determined by the heating of MPs having low Curie temperature (a FeCrNbB particulate system) injected within a malignant tissue, subjected to an ac magnetic field. The temperature evolution within healthy and tumor tissues was analyzed by finite element method simulations in a thermo-fluid model. The cooling effect produced by blood flowing in blood vessels was considered. This effect is intensified at the increase of blood velocity. The FeCrNbB particles, having the Curie temperature close to the therapeutic range, transfer the heat more homogeneous in the tumor keeping the temperature within the therapeutic range in whole tumor volume. Having the possibility to automatically control the temperature within a tumor, these particle type opens new research horizons in the magnetic hyperthermia.
A hybrid model for coupling kinetic corrections of fusion reactivity to hydrodynamic implosion simulations
Authors: Tang Xian-Zhu , McDevitt C. J. , Guo Zehua , Berk H. L.
Published: March 2014

Inertial confinement fusion requires an imploded target in which a central hot spot is surrounded by a cold and dense pusher. The hot spot/pusher interface can take complicated shape in three dimensions due to hydrodynamic mix. It is also a transition region where the Knudsen and inverse Knudsen layer effect can significantly modify the fusion reactivity in comparison with the commonly used value evaluated with background Maxwellians. Here, we describe a hybrid model that couples the kinetic correction of fusion reactivity to global hydrodynamic implosion simulations. The key ingredient is a non-perturbative treatment of the tail ions in the interface region where the Gamow ion Knudsen number approaches or surpasses order unity. The accuracy of the coupling scheme is controlled by the precise criteria for matching the non-perturbative kinetic model to perturbative solutions in both configuration space and velocity space.
The temporal evolution of the kinetic drift-Alfven instability of plasma shear flow
Authors: Mikhailenko V. V. , Mikhailenko V. S. , June Lee Hae , Koepke M. E.
Published: March 2014

The linear non-modal kinetic theory of the kinetic drift-Alfven instability, in the presence of shearing plasma flow, exhibits temporal non-modal amplitude growth with time-increasing growth rate. The drift-Alfven instability develops when the evolving frequencies of the density-gradient-driven drift wave and the kinetic Alfven wave become comparable and mode coupling increases significantly. Because the development of the instability depends on the plasma density gradient, drift-Alfven turbulence may be invoked as a possible turbulence driver in the edge pedestal, limiting the pedestal density gradients during the edge localized modes crash. In contrast to the case of shear-modified electrostatic drift-wave turbulence, the scattering of plasma ions by the shear-modified electromagnetic drift-Alven turbulence does not only suppress the turbulence, but can be responsible for transient increase in the instability's growth rate. The instability, i.e., turbulence, stabilizes when the drift and Alfven wave frequencies eventually become different enough that effective coupling between the two modes ends. So, perpendicular-flow shear can cause the growth rate to increase, decrease, become zero, and become negative as a result of shear's time-changing modification to the frequencies of the drift and Alfven waves.
Investigation of the depolarisation transition in Bi-based relaxor ferroelectrics
Authors: Woodward David I. , Dittmer Robert , Jo Wook , Walker David , Keeble Dean S. , Dale Matthew W. , Rödel Jürgen , Thomas Pam A.
Published: March 2014

The loss of macroscopic polarisation in relaxor ferroelectric (Na0.8K0.2)½Bi½TiO3 ceramics doped with BiZn½Ti½O3 has been studied by electrical and structural methods. These indicate that the phenomena that are coupled in a displacive phase transition are not necessarily coupled in the depolarisation of Na½Bi½TiO3-based relaxors and a concept of correlated and uncorrelated switching of dipoles within adjacent unit cells is used to explain this. Second harmonic generation performed on poled ceramics during heating yields values of the freezing temperature and shows a broad temperature range of ∼100 °C across which the structure changes from field-induced ferroelectric to an equilibrium-state ergodic relaxor. Electrical poling at room temperature causes poled regions to increase in size by ∼2 orders of magnitude. A model illustrating the main steps in thermal depolarisation is described that does not require a phase transition to take place on a unit cell level.
Achievement of high coercivity in sintered R-Fe-B magnets based on misch-metal by dual alloy method
Authors: Niu E , Chen Zhi-An , Chen Guo-An , Zhao Yu-Gang , Zhang Jin , Rao Xiao-Lei , Hu Bo-Ping , Wang Zhen-Xi
Published: March 2014

The R-Fe-B (R, rare earth) sintered magnets prepared with different ratio of alloys of MM-Fe-B (MM, misch-metal) and Nd-Fe-B by dual alloy method were investigated. As expected, the high ratio of MM-Fe-B alloy degrades the hard magnetic properties heavily with intrinsic coercivity lower than 5 kOe. When the atomic ratio MM/R ≤ 21.5% the magnetic properties can reach a practical level of Br ≥ 12.1 kGs, Hcj ≥ 10.7 kOe, and (BH)max ≥ 34.0 MGOe. And the effect of Hcj enhancement by the grain boundary diffusion process is obvious when MM/R ≤ 21.5%. It is revealed that the decrement of intrinsic magnetic properties of R2Fe14B matrix phase is not the main reason of the degradation of the magnets with high MM ratio. The change of deteriorated microstructure together with phase component plays fundamental roles in low Hcj. In high MM ratio magnets, (a) after annealing, Ce atoms inside main phase are inclined to be segregated in the outer layer of the main phase grains; (b) there is no thin layer of Ce-rich phase as an analogue of Nd-rich phase to separate main phase grains; (c) excessive Ce tends to form CeFe2 grains.
Analytical up-down asymmetric equilibria with non-parallel flows
Authors: Kuiroukidis Ap , Throumoulopoulos G. N.
Published: March 2014

Generic linear axisymmetric equilibria with plasma flow nonparallel to the magnetic field are obtained on the basis of a generalized Grad-Shafranov equation by employing an ansatz reducing the problem to a set of ordinary differential equations which can be solved recursively. In particular, an ITER like equilibrium with reversed magnetic shear and peaked current density is constructed and its characteristics are studied in connection with the flow. Also for parallel flows, the linear stability is examined by means of a sufficient condition. The results indicate that the flow may have a stabilizing effect.
The electronic transport behavior of hybridized zigzag graphene and boron nitride nanoribbons
Authors: Zhou Yuhong , Zhang Jianbing , Ye Cong , Miao Xiangshui , Zhang Daoli
Published: March 2014

In this present work, we have investigated the electronic transport properties of the hybridized structure constructed by the zigzag graphene and boron-nitride (BN) nanoribbons (Z-BnNmCp, n + m + p = 16) through employing nonequilibrium Green's functions in combination with the density-functional theory. The results demonstrate that the electronic transport properties of the hybridized Z-BnNmCp nanoribbons are strongly dependent on the width of boron-nitride or graphene nanoribbons. When the numbers of n and m are not equal, the negative differential resistance behavior is observed, which can be modulated by varying the width of BN nanoribbons. The conductance of the hybridized Z-BnNmCp nanoribbons with odd numbers of zigzag carbon chains also increases by the width of BN nanoribbons.
Transition threshold in GexSb10Se90−x glasses
Authors: Wei Wen-Hou , Fang Liang , Shen Xiang , Wang Rong-Ping
Published: March 2014

GexSb10Se90−x glasses with Ge content from 7.5 to 32.5 at. % have been prepared by melt-quench technique, and the physical parameters including glass transition temperature (Tg), density (ρ), compactness (C), shear elastic moduli (Cs), compression elastic moduli (Cc), refractive index (n), and optical bandgap (Eg) have been investigated. While all these physical parameters show threshold behavior in the glass with a chemically stoichiometric composition. Raman spectra analysis also indicates that, with increasing Ge content, Se-chains or rings gradually disappear until all Se-atoms are consumed in the glass with a chemically stoichiometric composition. With further increasing Ge content, homopolar Ge-Ge and Sb-Sb bonds are formed and the chemical order in the glasses is violated. The threshold behavior of the physical properties in the GexSb10Se90−x glasses can be traced to demixing of networks above the chemically stoichiometric composition.
Direct evaluation of ballistic phonon transport in a multi-walled carbon nanotube
Authors: Hayashi Hiroyuki , Takahashi Koji , Ikuta Tatsuya , Nishiyama Takashi , Takata Yasuyuki , Zhang Xing
Published: March 2014

Phonon confinement and in situ thermal conductance measurements in an individual multi-walled carbon nanotube (MWNT) are reported. Focused ion beam (FIB) irradiation was used to successively shorten a 4.8 μm long MWNT, eventually yielding a 0.3 μm long MWNT. After the first FIB irradiation, a 41% reduction in conductance was achieved, compared with that of the pristine MWNT. This was because the contributions from phonons with long free paths were excluded by scattering at FIB-induced defects. Phonon transport in linked multiple-length nanotubes was also investigated.
Strong ferromagnetic-dielectric coupling in multiferroic Lu2CoMnO6 single crystals
Authors: Lee N. , Choi H. Y. , Jo Y. J. , Seo M. S. , Park S. Y. , Choi Y. J.
Published: March 2014

We have grown single crystals of multiferroic double-perovskite Lu2CoMnO6 and studied the directional dependence of their magnetic and dielectric properties. The ferromagnetic order emerges below TC ≈ 48 K along the crystallographic c axis. Dielectric anomaly arises along the b axis at TC, contrary to the polycrystalline work suggesting ferroelectricity along the c axis. Through the strongly coupled ferromagnetic and dielectric states, the highly non-linear variation of both dielectric constant and magnetization was achieved in application of magnetic fields. This concurrent tunability provides an efficient route to manipulation of multiple order parameters in multiferroics.
Roles learners believe they have in the development of their language learning – autonomy included?
Authors: Nicolaides Christine Siqueira
Published: March 2014

Through data generated in an ethnographic research project, which studies language learners (future English teachers), it was possible to observe that learners voice the importance of being in control of their own learning. Nevertheless, in the academic context, it seems they have an imaginary territory, where they can or cannot exercise autonomy. In the classroom, they agree that the one who owns the knowledge (teacher) should be in charge of class management, which includes the determination of content, duration of the activities etc. From the learners’ perspective, besides being the one who knowsthe content, the teacher is the one that knows the best way to learn too. Outside the classroom, though, the situation changes: they feel freer to act according to their own learning beliefs and empowered to make their own decisions. All these data have been collected during a whole school year, at Catholic University of Pelotas – Brazil, when the researcher tried to construct an emic view with her participants using a range of research methods.
Policespeak
Authors: Hall Phil
Published: March 2014

This chapter focuses on the spoken language of police communication or “policespeak”. It examines a number of the readily recognisable clichés and formulaic expressions that are widely regarded as characteristic of policespeak. It also looks at some facets of police work which promote specific behaviours which are less overtly characteristic of policespeak but are nonetheless strongly motivated by the demands of their contexts of use. The final portion of the chapter shows how policespeak is used as means of accommodation by interactants who are not police officers. In addressing policespeak from these various angles, the chapter attempts where possible and practical to address the contextual factors motivating the observed behaviours.
Questioning in common law criminal courts
Authors: Gibbons John
Published: March 2014

Questions in everyday discourse consist of a situated exchange in which the questioner and answerer are in a roughly symmetrical relationship in which each is entitled to request information from the other. Questioners typically do not have the information that they are requesting. The answerer is not obliged to answer, but there is a normal Gricean expectation that the answer will provide the information requested. Courtroom questioning differs markedly, in that lawyers usually have a particular version of events in mind that they are attempting to confirm with the witness. Usually witnesses are compelled to answer, and do not have the right to ask questions. Therefore courtroom questions differ from everyday questions in both their social and their information characteristics.

These differences mean that courtroom questions are different from everyday questions along a range of linguistic parameters. At the overall narrative or spoken text level, the lawyer is constructing a version of events element by element – neither he nor the witness normally provides a full narrative during the interaction. At the exchange level, normally only the lawyer asks questions, and only the witness answers questions – an asymmetrical pattern – and evaluative lawyer third parts are common. At the level of question structure, coercive grammatical forms are strongly over-represented when compared to everyday conversation.
Bilingual courtrooms: In the interests of justice?
Authors: Powell Richard
Published: March 2014

Bilingual courtrooms are generally associated with the use of interpreted oral testimony to support monolingual judicial proceedings. Yet several postcolonial jurisdictions accord de jure or de facto standing to more than one language in court. The most studied is Malaysia, but the literature is far from exhaustive. Further research is to be encouraged because the way different legal systems accommodate bilingualism throws light on many questions central to forensic linguistics, including language rights, language planning in legal domains, cultural disadvantage before the law, genre-based communication strategies, and transparency of legal processes. This chapter reviews current evidence of and research into bilingual courtrooms and discusses the problems and potential benefits of including data on bilingual discourse in debates about language and justice.