bluuebunny/crossref_metadata_2025 huggingface dataset:
Life in extreme environments: single molecule force spectroscopy as a tool to explore proteins from extremophilic organisms
Authors: Tych Katarzyna M. , Hoffmann Toni , Batchelor Matthew , Hughes Megan L. , Kendrick Katherine E. , Walsh Danielle L. , Wilson Michael , Brockwell David J. , Dougan Lorna
Published: August 2015

Extremophiles are organisms which survive and thrive in extreme environments. The proteins from extremophilic single-celled organisms have received considerable attention as they are structurally stable and functionally active under extreme physical and chemical conditions. In this short article, we provide an introduction to extremophiles, the structural adaptations of proteins from extremophilic organisms and the exploitation of these proteins in industrial applications. We provide a review of recent developments which have utilized single molecule force spectroscopy to mechanically manipulate proteins from extremophilic organisms and the information which has been gained about their stability, flexibility and underlying energy landscapes.
Fatty acyl donor selectivity in membrane bound O-acyltransferases and communal cell fate decision-making
Authors: Tuladhar Rubina , Lum Lawrence
Published: August 2015

The post-translational modification of proteins with lipid moieties confers spatial and temporal control of protein function by restricting their subcellular distribution or movement in the extracellular milieu. Yet, little is known about the significance of lipid selectivity to the activity of proteins targeted for such modifications. Membrane bound O-acyl transferases (MBOATs) are a superfamily of multipass enzymes that transfer fatty acids on to lipid or protein substrates. Three MBOATs constitute a subfamily with secreted signalling molecules for substrates, the Wnt, Hedgehog (Hh) and Ghrelin proteins. Given their important roles in adult tissue homoeostasis, all three molecules and their respective associated acyltransferases provide a framework for interrogating the role of extracellular acylation events in cell-to-cell communication. Here, we discuss how the preference for a fatty acyl donor in the Wnt acyltransferase porcupine (Porcn) and possibly in other protein lipidation enzymes may provide a means for coupling metabolic health at the single cell level to communal cell fate decision-making in complex multicellular organisms.
NRF2 and microRNAs: new but awaited relations
Authors: Kurinna Svitlana , Werner Sabine
Published: August 2015

The nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor is a key player in the cellular antioxidant response and it also controls various other functions in a cell-type specific manner. Due to these key functions, a tight control of NRF2 expression and activity is essential. This regulation is exerted at multiple levels, including transcriptional regulation and proteasomal degradation. Recent studies revealed important roles of miRNAs (miRs) in the control of NRF2 activity through direct targeting of the NRF2 mRNA and of mRNAs encoding proteins that control the level and activity of NRF2. In addition, NRF2 itself has been identified as a regulator of miRs, which exert some of the functions of NRF2 in metabolic regulation and also novel functions in the regulation of cell adhesion. Here, we summarize the roles and mechanisms of action of miRs in the regulation of NRF2 activity and as downstream effectors of this transcription factor.
The blood–brain barrier endothelium: a target for pro-inflammatory cytokines
Authors: Rochfort Keith D. , Cummins Philip M.
Published: August 2015

An intact functioning blood–brain barrier (BBB) is fundamental to proper homoeostatic maintenance and perfusion of the central nervous system (CNS). Inflammatory damage to the unique microvascular endothelial cell monolayer that constitutes the luminal BBB surface, leading to elevated capillary permeability, has been linked to various neurological disorders ranging from ischaemic stroke and traumatic brain injury, to neurodegenerative disease and CNS infections. Moreover, the neuroinflammatory cascade that typically accompanies BBB failure in these circumstances has been strongly linked to elevated levels of pro-inflammatory cytokines such as tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). This mini review will examine our current knowledge of how cytokines may dysregulate the interendothelial paracellular pathway leading to elevated BBB permeability. The mechanistic role of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase)-induced oxidative stress in these events will also be addressed.
Chemical reporters for exploring protein acylation
Authors: Thinon Emmanuelle , Hang Howard C.
Published: August 2015

Proteins are acylated by a variety of metabolites that regulates many important cellular pathways in all kingdoms of life. Acyl groups in cells can vary in structure from the smallest unit, acetate, to modified long-chain fatty acids, all of which can be activated and covalently attached to diverse amino acid side chains and consequently modulate protein function. For example, acetylation of Lys residues can alter the charge state of proteins and generate new recognition elements for protein–protein interactions. Alternatively, long-chain fatty-acylation targets proteins to membranes and enables spatial control of cell signalling. To facilitate the analysis of protein acylation in biology, acyl analogues bearing alkyne or azide tags have been developed that enable fluorescent imaging and proteomic profiling of modified proteins using bioorthogonal ligation methods. Herein, we summarize the currently available acylation chemical reporters and highlight their utility to discover and quantify the roles of protein acylation in biology.
Keap1/Nrf2 pathway in the frontiers of cancer and non-cancer cell metabolism
Authors: Chartoumpekis Dionysios V. , Wakabayashi Nobunao , Kensler Thomas W.
Published: August 2015

Cancer cells adapt their metabolism to their increased needs for energy and substrates for protein, lipid and nucleic acid synthesis. Nuclear erythroid factor 2-like 2 (Nrf2) pathway is usually activated in cancers and has been suggested to promote cancer cell survival mainly by inducing a large battery of cytoprotective genes. This mini review focuses on metabolic pathways, beyond cytoprotection, which can be directly or indirectly regulated by Nrf2 in cancer cells to affect their survival. The pentose phosphate pathway (PPP) is enhanced by Nrf2 in cancers and aids their growth. PPP has also been found to be up-regulated in non-cancer tissues and other pathways, such as de novo lipogenesis, have been found to be repressed after activation of the Nrf2 pathway. The importance of these Nrf2-regulated metabolic pathways in cancer compared with non-cancer state remains to be determined. Last but not least, the importance of context about Nrf2 and cancer is highlighted as the Nrf2 pathway may be activated in cancers but its pharmacological activators are useful in chemoprevention.
The methodology of TSPO imaging with positron emission tomography
Authors: Turkheimer Federico E. , Rizzo Gaia , Bloomfield Peter S. , Howes Oliver , Zanotti-Fregonara Paolo , Bertoldo Alessandra , Veronese Mattia
Published: August 2015

The 18-kDA translocator protein (TSPO) is consistently elevated in activated microglia of the central nervous system (CNS) in response to a variety of insults as well as neurodegenerative and psychiatric conditions. It is therefore a target of interest for molecular strategies aimed at imaging neuroinflammation in vivo. For more than 20 years, positron emission tomography (PET) has allowed the imaging of TSPO density in brain using [11C]-(R)-PK11195, a radiolabelled-specific antagonist of the TSPO that has demonstrated microglial activation in a large number pathological cohorts. The significant clinical interest in brain immunity as a primary or comorbid factor in illness has sparked great interest in the TSPO as a biomarker and a surprising number of second generation TSPO radiotracers have been developed aimed at improving the quality of TSPO imaging through novel radioligands with higher affinity. However, such major investment has not yet resulted in the expected improvement in image quality. We here review the main methodological aspects of TSPO PET imaging with particular attention to TSPO genetics, cellular heterogeneity of TSPO in brain tissue and TSPO distribution in blood and plasma that need to be considered in the quantification of PET data to avoid spurious results as well as ineffective development and use of these radiotracers.
Communication Development in Early-Identified Children With Mild Bilateral and Unilateral Hearing Loss
Authors: Fitzpatrick Elizabeth M. , Durieux-Smith Andrée , Gaboury Isabelle , Coyle Douglas , Whittingham JoAnne
Published: August 2015

Purpose

This clinical focus article provides preliminary findings from a multicenter longitudinal study investigating auditory and communication development in children with mild bilateral or unilateral hearing loss of any degree.

Method

A total of 100 children (55 with mild bilateral or unilateral hearing loss and 45 with normal hearing) underwent 1 or more assessments from a battery of auditory and language measures.

Results

Children up to age 4 years demonstrated auditory and language skills similar to those of children with normal hearing.

Conclusions

Factors that affect outcomes in communication development will be explored as additional data are collected in this ongoing study.
Is Early Intervention Effective in Improving Spoken Language Outcomes of Children With Congenital Hearing Loss?
Authors: Ching Teresa Y. C.
Published: August 2015

Purpose

The purpose of this research forum article was to present research findings on the effectiveness of early intervention for improving outcomes of children with congenital hearing loss.

Method

The method involved a narrative overview of recent findings from the Longitudinal Outcomes of Children with Hearing Impairment study.

Results

Early intervention, either in the form of amplification or cochlear implantation, was associated with higher language scores. Maternal education and communication mode used during early intervention were also significant contributors to child outcomes. Early performance predicted later language development.

Conclusion

Early intervention is effective in improving early language outcomes, at a population level.
Developing a Phonological Awareness Curriculum: Reflections on an Implementation Science Framework
Authors: Goldstein Howard , Olszewski Arnold
Published: August 2015

Purpose

This article describes the process of developing and implementing a supplemental early literacy curriculum designed for preschoolers demonstrating delays in literacy development.

Method

Intervention research and implementation research have traditionally been viewed as sequential processes. This article illustrates a process of intervention development that was paralleled by a focus on implementation in early childhood settings. The exploration, preparation, implementation, sustainment framework is used to describe factors that need to be considered during a progression through these 4 phases of implementation. A post hoc analysis provides insight into a rather nonlinear progression of intervention development and highlights considerations and activities that have facilitated implementation.

Conclusions

The guiding principles of the exploration, preparation, implementation, sustainment implementation science framework highlight the important considerations in developing effective and practical interventions. Considering implementation and sustainment during the intervention development process and using data-based decision making has the potential to expand the availability of user-friendly evidence-based practices in communication sciences and disorders and encourage a bridging of the researcher–clinician gap.
Improved signal‐to‐noise ratio estimation algorithm for asymmetric pulse‐shaped signals
Authors: Shao Huaizong , Wu Di , Li Yang , Liu Wuling , Chu Xiaoli
Published: August 2015

The split‐symbol moment estimation (SSME) algorithm is a conventional method to estimate the signal‐to‐noise ratio (SNR) in communication systems for M‐ary phase shift keying signals. However, the conventional SSME is based on the assumption of symmetric pulse‐shaping waveforms, and becomes no longer proper when the shaping pulse is asymmetric. In this study, the authors propose a modified SSME algorithm for asymmetric pulse‐shaped signals, based on an odd‐even symbol splitting approach. Simulation results show that the modified SSME outperforms the conventional SSME for both symmetric and asymmetric pulse‐shaped signals in terms of SNR estimation accuracy.
Comprehensive design of disturbance observer and non‐singular terminal sliding mode control for reusable launch vehicles
Authors: Su Rui , Zong Qun , Tian Bailing , You Ming
Published: August 2015

A multivariable non‐singular terminal sliding mode control (NTSMC) strategy is developed combining disturbance observer (DO) technique for the six‐degree‐of‐freedom reusable launch vehicles. First of all, the control‐oriented model is established, followed by a design of finite‐time DO, which is to estimate the model uncertainties and external disturbances. Second, based on the disturbance estimation, a composite controller combining multivariable NTSMC is developed to make the attitude tracking errors converge to zero in finite time. And then the stability of the closed‐loop system is guaranteed through Lyapunov theory. Finally, the simulation results illustrate that the comprehensive control strategy performs well in tracking the guidance commands in spite of model uncertainties and external disturbances.
Performance recovery of intelligent digital redesign for observer‐based output feedback under immeasurable premise variables
Authors: Moon Ji Hyun , Lee Ho Jae
Published: August 2015

This study discusses an intelligent digital redesign (IDR) for observer‐based output‐feedback controllers in Takagi–Sugeno form under immeasurable premise variables. A delta operator that asymptotically connects an analogue control system with its discrete‐time model is adopted. The condition for the IDR problem with stability is proposed in terms of matrix inequality. The authors show that the proposed IDRed sampled‐data controller recovers the analogue control performance from the perspective of the closed‐loop trajectory under the fast sampling limit.
Robust output synchronisation of non‐identical linear agents via internal model principle
Authors: Wu Yuanqing , Wu Zhengguang , Su Hongye
Published: August 2015

This study investigates the output synchronisation of a heterogeneous network of agents affected by parameter perturbations. The authors use the output regulation theory to solve this problem. The main result is the construction of the reference generators and the robust regulators, which can guarantee the outputs of the non‐identical agents track the output of the leader. The designed method includes two steps, which can be seen as a kind of separation principle. Firstly, the outputs of a network of local identical reference generators are forced to asymptotically follow the output of the leader. Secondly, under the control of an individual regulator, the output of each agent is forced to track the output of the corresponding local reference generator, via robust output regulation theory.
Fuel–air ratio control for a spark ignition engine using gain‐scheduled delay‐dependent approach
Authors: Yin Hai , Liu Zhiyuan
Published: August 2015

A novel approach to fuel–air ratio (FAR) control for spark ignition (SI) engines is presented in this study. The FAR dynamics are modelled as a first‐order plus time‐varying delay system. Time delay in the control plant is not approximated using the Pade formula. For controller design purposes, it is described as a time‐varying delay in the measurement output. A gain‐scheduled delay‐dependent controller, regarding the time delay as a time‐varying parameter, is then designed to track FAR reference and minimise the effects of disturbances on FAR regulation. The proposed controller guarantees the stability of closed‐loop system and induced L2 norm performance using Lyapunov–Krasovskii functional. The design method is then formulated in terms of linear matrix inequalities that leads to a convex optimisation problem and can be solved by parameter gridding technique. Simulation results validate the FAR regulation of proposed controller over the large range of time delay, which covers most engine operating conditions in practice.
Control of virtual power plant in microgrids: a coordinated approach based on photovoltaic systems and controllable loads
Authors: Liu Yun , Xin Huanhai , Wang Zhen , Gan Deqiang
Published: August 2015

Renewable energy sources (RESs) such as solar energy are cost‐effective to meet part of the energy needs. However, the inherent fluctuation and intermittence of RESs may deteriorate the stability and security of power grids. Energy storage systems can mitigate the problem, but they are very expensive. For this reason, a coordinated control method of virtual power plant (VPP), which includes photovoltaic systems (PVs) and controllable loads, is proposed in this study so that the aggregated power output of the VPP can be flexibly adjusted in a wide range. To achieve this, power output of the PVs and operational modes of controllable loads are coordinated by solving a mixed integer programming (MIP) problem. Meanwhile, with a quadratic interpolation based active power control strategy, each PV can operate in a power dispatch mode and simultaneously estimate its maximum available power, which is an input to the MIP problem. Externally, the VPP can quickly adjust the aggregated power and achieve functions important to power systems with high penetration of distributed energy resources, such as primary frequency regulation. Simulation results validate the effectiveness of VPP in providing frequency support to an island microgrid.
High‐gain dual‐band dual‐polarised electromagnetic band gap resonator antenna with an all‐dielectric superstructure
Authors: Zeb Basit Ali , Esselle Karu P.
Published: August 2015

Two identical unprinted dielectric slabs are placed above a dual‐polarised (DP) stacked‐patch feed antenna to transform its less‐directive radiation into almost equal and high‐gain DP beams in two frequency bands. The dual‐band operation is achieved by engineering the reflection characteristics of a classical all‐dielectric superstructure such that cavity resonance condition is satisfied in two frequency bands. A prototype of this dual‐polarised electromagnetic band gap resonator antenna with a frequency ratio of 1.245 has been fabricated and measured peak gains of 17 and 16.6 dBi at 10.6 and 13.15 GHz, respectively, and cross‐polarisation levels of less than –18 dB, have been achieved. The proposed antenna has a simple configuration and is easy to manufacture, making it a good candidate for DP point‐to‐point wireless links.
Response of wind power park modules in distribution systems to transmission network faults during reverse power flows
Authors: Boemer Jens C. , Rawn Barry G. , Gibescu Madeleine , van der Meijden Mart A.M.M. , Kling Wil L.
Published: August 2015

Penetration levels of distributed wind power park modules (WPPMs) reach such high levels in parts of the world, for example, Germany, that reverse power flows (RPFs) from distribution to transmission level occur regularly in certain areas of the power system. This study compares the impact of normal and RPFs on the network fault response of WPPMs in distribution systems that are prone to fault‐induced delayed voltage recovery issues for a fault in the transmission system. The study contributes to the ongoing discussion on grid connection requirements for WPPMs and raises awareness of a prolonged low‐voltage ride‐through (LVRT) operation of WPPMs when these are set to ride‐through faults in ‘blocking mode’, during which the set‐points for the active and reactive currents are set to zero. For RPFs such LVRT operation causes a substantial sustained active power deficit in power system areas with high penetration of distributed WPPMs and potentially leads to a stability risk.
Electroless deposition method for silver‐coated carbon fibres
Authors: Liu Guilin , Xu Chunju , Chen Huiyu , Hou Xin , Liu Yaqing
Published: August 2015

Silver (Ag)‐coated carbon fibres (CFs) have been successfully fabricated at 30°C via a simple electroless deposition method, and glucose was used as a green reducing agent. The phase purity and microstructures of the Ag coatings were characterised by X‐ray diffraction and a scanning electron microscope equipped with energy‐dispersive spectroscopy. It was found that the dosage of sodium hydroxide and the reaction time played important roles in Ag deposition. The CFs with a compact and continuous Ag layer possessed excellent conductivity, and the volume resistivity could reach 5.59 × 10−4 Ω cm. Such composites with high electrical conductivity have potential applications in fibre–matrix composites, shielding materials and so on.
Control of one‐dimensional hydroxyapatite nanocrystals at mild conditions: organic additive effects
Authors: Kong Deyan , Xiao Xinli , Yang Yulin
Published: August 2015

One‐dimensional hydroxyapatite (HAp, Ca10 (PO4)6 (OH)2) nanocrystals have been successfully synthesised via the simple precipitation‐hydrolysis process on mild solution conditions. At the first precipitation step, the precursor samples of monetite phase CaHPO4 were prepared with three kinds of organic additives. The results of X‐ray diffraction (XRD) patterns show that the structure and crystallinity of CaHPO4 prepared with the different organic additives are different, which indicates that the organic additives exert influence on the crystal growth of CaHPO4. During the second process, the HAp nanocrystals with high aspect ratio grew up under a high pH condition. The XRD patterns show that the preference of every nanocrystal growth is the (002) plane. Transmission electron microscopy micrographs indicate that the HAp nanocrystals were affected by the reaction temperature and the pH values of the solution. The organic additives influenced the aspect ratio of HAp nanocrystals, and Fourier transform infrared spectra show that the organic additives were completely dissolved in the aqueous system. This indicates that the organic additives affected the formation of nucleation and growth of HAp nanocrystals, and the influence gradually decreased with the extension of the hydrolysis time, until the organic additives were detached from the HAp crystals.
Gender studies and interdisciplinarity
Authors: Woodward Kath , Woodward Sophie
Published: August 2015

In this article we consider the example of gender studies as an interdisciplinary field, and argue that gender studies, and women’s studies, from which gender studies developed, has a distinctive engagement with interdisciplinarity. By thinking about the trajectory of women’s studies, feminist thinking and gender studies, we suggest that this has always been an interdisciplinary field of study. We trace both the shifts and continuities in thinking between different iterations of feminist thinking to consider the three core fields of: gender, sex and sexuality; intersectionality and activism; theory and methods. The article aims to open up debate over what the constructive possibilities are of a focus upon gender, and what the relationship is between theory and activism. This article is published as part of an ongoing collection dedicated to interdisciplinary research.
Note: Electrochemical cell for in operando X-ray diffraction measurements on a conventional X-ray diffractometer
Authors: Hartung Steffen , Bucher Nicolas , Bucher Ramona , Srinivasan Madhavi
Published: August 2015

Electrochemical in operando X-ray diffraction (XRD) is a powerful method to analyze structural changes of energy storage materials while inserting/de-inserting charge carriers, such as Li- or Na-ions, into/from a host structure. The design of an XRD in operando cell is presented, which enables the use of thin (6 μm) aluminum foil as X-ray window as a non-toxic alternative to conventional beryllium windows. Owing to the reduced thickness, diffraction patterns and their changes during cycling can be observed with excellent quality, which was demonstrated for two cathode materials for sodium-ion batteries in a half-cell set-up, P2-Na0.7MnO2 and Na2.55V6O16 ⋅ 0.6H2O.
Simulations of in situ x-ray diffraction from uniaxially compressed highly textured polycrystalline targets
Authors: McGonegle David , Milathianaki Despina , Remington Bruce A. , Wark Justin S. , Higginbotham Andrew
Published: August 2015

A growing number of shock compression experiments, especially those involving laser compression, are taking advantage of in situ x-ray diffraction as a tool to interrogate structure and microstructure evolution. Although these experiments are becoming increasingly sophisticated, there has been little work on exploiting the textured nature of polycrystalline targets to gain information on sample response. Here, we describe how to generate simulated x-ray diffraction patterns from materials with an arbitrary texture function subject to a general deformation gradient. We will present simulations of Debye-Scherrer x-ray diffraction from highly textured polycrystalline targets that have been subjected to uniaxial compression, as may occur under planar shock conditions. In particular, we study samples with a fibre texture, and find that the azimuthal dependence of the diffraction patterns contains information that, in principle, affords discrimination between a number of similar shock-deformation mechanisms. For certain cases, we compare our method with results obtained by taking the Fourier transform of the atomic positions calculated by classical molecular dynamics simulations. Illustrative results are presented for the shock-induced α–ϵ phase transition in iron, the α–ω transition in titanium and deformation due to twinning in tantalum that is initially preferentially textured along [001] and [011]. The simulations are relevant to experiments that can now be performed using 4th generation light sources, where single-shot x-ray diffraction patterns from crystals compressed via laser-ablation can be obtained on timescales shorter than a phonon period.
Magnetisation reversal in anisotropy graded Co/Pd multilayers
Authors: Barton C. W. , Thomson T.
Published: August 2015

We demonstrate high precision controllability of the magnetization reversal nucleation process in [Co/Pd]8 multilayer films consisting of two sets of bilayers with high and low perpendicular anisotropy, respectively. The anisotropy of the entire film is set by the degree of Co/Pd interfacial mixing during deposition which provides fine control of the anisotropy of an individual bilayer in the multilayer stack. The relative number of each type of bilayer is used to select the magnetisation reversal behavior such that changing one bilayer changes the properties of the entire multilayer through anisotropy averaging. A simple extension to the sputtering protocol would provide multilayer films with fully graded anisotropy, while maintaining a constant saturation magnetization opening new possibilities for the creation of highly engineered multilayer structures for spin torque devices and future magnetic recording media.
Measurement of the transmission phase of an electron in a quantum two-path interferometer
Authors: Takada S. , Yamamoto M. , Bäuerle C. , Watanabe K. , Ludwig A. , Wieck A. D. , Tarucha S.
Published: August 2015

A quantum two-path interferometer allows for direct measurement of the transmission phase shift of an electron, providing useful information on coherent scattering problems. In mesoscopic systems, however, the two-path interference is easily smeared by contributions from other paths, and this makes it difficult to observe the true transmission phase shift. To eliminate this problem, multi-terminal Aharonov-Bohm (AB) interferometers have been used to derive the phase shift by assuming that the relative phase shift of the electrons between the two paths is simply obtained when a smooth shift of the AB oscillations is observed. Nevertheless, the phase shifts using such a criterion have sometimes been inconsistent with theory. On the other hand, we have used an AB ring contacted to tunnel-coupled wires and acquired the phase shift consistent with theory when the two output currents through the coupled wires oscillate with well-defined anti-phase. Here, we investigate thoroughly these two criteria used to ensure a reliable phase measurement, the anti-phase relation of the two output currents, and the smooth phase shift in the AB oscillation. We confirm that the well-defined anti-phase relation ensures a correct phase measurement with a quantum two-path interference. In contrast, we find that even in a situation where the anti-phase relation is less well-defined, the smooth phase shift in the AB oscillation can still occur but does not give the correct transmission phase due to contributions from multiple paths. This indicates that the phase relation of the two output currents in our interferometer gives a good criterion for the measurement of the true transmission phase, while the smooth phase shift in the AB oscillation itself does not.
Influence of weak vibrational-electronic couplings on 2D electronic spectra and inter-site coherence in weakly coupled photosynthetic complexes
Authors: Monahan Daniele M. , Whaley-Mayda Lukas , Ishizaki Akihito , Fleming Graham R.
Published: August 2015

Coherence oscillations measured in two-dimensional (2D) electronic spectra of pigment-protein complexes may have electronic, vibrational, or mixed-character vibronic origins, which depend on the degree of electronic-vibrational mixing. Oscillations from intrapigment vibrations can obscure the inter-site coherence lifetime of interest in elucidating the mechanisms of energy transfer in photosynthetic light-harvesting. Huang-Rhys factors (S) for low-frequency vibrations in Chlorophyll and Bacteriochlorophyll are quite small (S ≤ 0.05), so it is often assumed that these vibrations influence neither 2D spectra nor inter-site coherence dynamics. In this work, we explore the influence of S within this range on the oscillatory signatures in simulated 2D spectra of a pigment heterodimer. To visualize the inter-site coherence dynamics underlying the 2D spectra, we introduce a formalism which we call the “site-probe response.” By comparing the calculated 2D spectra with the site-probe response, we show that an on-resonance vibration with Huang-Rhys factor as small as S = 0.005 and the most strongly coupled off-resonance vibrations (S = 0.05) give rise to long-lived, purely vibrational coherences at 77 K. We moreover calculate the correlation between optical pump interactions and subsequent entanglement between sites, as measured by the concurrence. At 77 K, greater long-lived inter-site coherence and entanglement appear with increasing S. This dependence all but vanishes at physiological temperature, as environmentally induced fluctuations destroy the vibronic mixing.
Thermochemical and kinetic aspects of Cu2ZnSn(S,Se)4 thin film growth by reacting Cu-Zn-Sn precursors in H2S and H2Se
Authors: Mangan Thomas C. , McCandless Brian E. , Dobson Kevin D. , Birkmire Robert W.
Published: August 2015

Electrodeposited thin-film Cu-Zn-Sn samples were reacted in varying ratios of mixed Ar/H2S/H2Se to form Cu2ZnSn(S,Se)4 (CZTSSe). Reactions were carried out at atmospheric pressure, reaching a temperature of 550 °C. Sulfur/selenium ratios in reacted films were determined as a function of [H2S]/[H2Se] in the reaction atmosphere. Relative S/Se incorporation into the CZTSSe films was used to estimate the Gibbs free energy of quaternary Cu2ZnSnSe4 to be ΔGCZTSe823K≈−675 kJ·mol−1. When chalcogen species are supplied from hydride gas sources, formation of the selenide quaternary is favored over the sulfide.
A semiclassical treatment of the
ℓ
–
j
correlation in atom-diatom collisions
Authors: Aldegunde J. , González–Sánchez L. , Jambrina P. G. , Sáez-Rábanos V. , Aoiz F. J.
Published: August 2015

The explicit consideration of the vector correlations is an essential step when it comes to determining the mechanism of chemical reactions. Usual vector correlations involve initial and final relative velocity vectors and rotational angular momenta. However, the correlation between the orbital, ℓ, and rotational, j, angular momenta has seldom received any attention. In this article, we present a semiclassical methodology capable of describing the ℓ–j correlation that may serve as a connection between the quantum and quasiclassical treatments. Using the scattering matrix in the orbital angular momentum representation, the ℓ–j correlation is expressed as a probability density function of the angle formed by both vectors. This technique is exemplified through the H + D2 reaction and its accuracy is appraised by comparing with results derived from calculations based on quasiclassical trajectories.
Temperature effect on exchange coupling and magnetization reversal in antiferromagnetically coupled (Co/Pd) multilayers
Authors: Sbiaa R. , Al-Omari I. A. , Kharel P. R. , Ranjbar M. , Sellmyer D. J. , Åkerman J. , Piramanayagam S. N.
Published: August 2015

Magnetization reversal of antiferromagnetically coupled (AFC) soft and hard (Co/Pd) multilayers was studied as a function of temperature. While the hard [Co(0.3 nm)/Pd(0.8 nm)]×10 was kept unchanged, the softness of the [Co(t)/Pd(0.8 nm)]×3 was controlled by varying the thickness t of the Co sublayer. Clear two-step hysteresis loops were observed for all the investigated multilayers with t ranging between 0.4 and 1 nm. The spin reorientation of the soft layer magnetization from in-plane direction to out-of-plane direction was investigated from 50 to 300 K. The antiferromagnetic field HAFC measured from the shift of the minor hysteresis loop reveals a good agreement to the quantum-well model. From the out-of-plane hysteresis loop of the uncoupled soft layer, its magnetization shows an in-plane orientation for t ≥ 0.6 nm. The strong HAFC helps to induce an out-of plane orientation of the soft layer with a linear decrease of its coercivity with temperature. These investigated structures show the possibility to reduce the unwanted stray field and improving the out-of-plane anisotropy even for relatively thicker soft layer.
Investigation of the Fe3+ centers in perovskite KMgF3 through a combination of ab initio (density functional theory) and semi-empirical (superposition model) calculations
Authors: Emül Y. , Erbahar D. , Açıkgöz M.
Published: August 2015

Analyses of the local crystal and electronic structure in the vicinity of Fe3+ centers in perovskite KMgF3 crystal have been carried out in a comprehensive manner. A combination of density functional theory (DFT) and a semi-empirical superposition model (SPM) is used for a complete analysis of all Fe3+ centers in this study for the first time. Some quantitative information has been derived from the DFT calculations on both the electronic structure and the local geometry around Fe3+ centers. All of the trigonal (K-vacancy case, K-Li substitution case, and normal trigonal Fe3+ center case), FeF5O cluster, and tetragonal (Mg-vacancy and Mg-Li substitution cases) centers have been taken into account based on the previously suggested experimental and theoretical inferences. The collaboration between the experimental data and the results of both DFT and SPM calculations provides us to understand most probable structural model for Fe3+ centers in KMgF3.
Gyrokinetic and kinetic particle-in-cell simulations of guide-field reconnection. I. Macroscopic effects of the electron flows
Authors: Muñoz P. A. , Told D. , Kilian P. , Büchner J. , Jenko F.
Published: August 2015

In this work, we compare gyrokinetic (GK) with fully kinetic Particle-in-Cell (PIC) simulations of magnetic reconnection in the limit of strong guide field. In particular, we analyze the limits of applicability of the GK plasma model compared to a fully kinetic description of force free current sheets for finite guide fields (bg). Here, we report the first part of an extended comparison, focusing on the macroscopic effects of the electron flows. For a low beta plasma (βi = 0.01), it is shown that both plasma models develop magnetic reconnection with similar features in the secondary magnetic islands if a sufficiently high guide field (bg ≳ 30) is imposed in the kinetic PIC simulations. Outside of these regions, in the separatrices close to the X points, the convergence between both plasma descriptions is less restrictive (bg ≳ 5). Kinetic PIC simulations using guide fields bg ≲ 30 reveal secondary magnetic islands with a core magnetic field and less energetic flows inside of them in comparison to the GK or kinetic PIC runs with stronger guide fields. We find that these processes are mostly due to an initial shear flow absent in the GK initialization and negligible in the kinetic PIC high guide field regime, in addition to fast outflows on the order of the ion thermal speed that violate the GK ordering. Since secondary magnetic islands appear after the reconnection peak time, a kinetic PIC/GK comparison is more accurate in the linear phase of magnetic reconnection. For a high beta plasma (βi = 1.0) where reconnection rates and fluctuations levels are reduced, similar processes happen in the secondary magnetic islands in the fully kinetic description, but requiring much lower guide fields (bg ≲ 3).
Early evolution of the angiosperm clade Asteraceae in the Cretaceous of Antarctica
Authors: Barreda Viviana D. , Palazzesi Luis , Tellería Maria C. , Olivero Eduardo B. , Raine J. Ian , Forest Félix
Published: August 2015

Significance

The flowering plant family Asteraceae (e.g. sunflowers, daisies, chrysanthemums), with about 23,000 species, is found almost everywhere in the world except in Antarctica. Asteraceae (or Compositae) are regarded as one of the most influential families in the diversification and evolution of a large number of animals that heavily depends on their inflorescences to survive (e.g. bees, hummingbirds, wasps). Here we report the discovery of pollen grains unambiguously assigned to Asteraceae that remained buried in Antarctic deposits for more than 65 million years along with other extinct groups (e.g. Dinosaurs, Ammonites). Our discovery drastically pushes back the assumed origin of Asteraceae, because these pollen grains are the oldest fossils ever found for the family.
Computational dissection of human episodic memory reveals mental process-specific genetic profiles
Authors: Luksys Gediminas , Fastenrath Matthias , Coynel David , Freytag Virginie , Gschwind Leo , Heck Angela , Jessen Frank , Maier Wolfgang , Milnik Annette , Riedel-Heller Steffi G. , Scherer Martin , Spalek Klara , Vogler Christian , Wagner Michael , Wolfsgruber Steffen , Papassotiropoulos Andreas , de Quervain Dominique J.-F.
Published: August 2015

Significance

Human memory is a highly heritable and complex trait that is the outcome of several neurobiologically distinct mental processes, such as learning, memory maintenance, and emotional modulation of memory strength. Such processes, which are not always amenable to direct observation, can be dissociated using computational models. Here we provide converging evidence linking computational model parameters and related behavioral and neuroimaging phenotypes to sets of biologically related genes in several populations of healthy young and elderly adults. Our findings suggest that distinct genetic profiles underlie specific mental processes of human episodic memory. Understanding the genetic and neural bases of such processes is essential for the development of novel therapeutic approaches that could lead to a better treatment of neuropsychiatric disorders.
CBP30, a selective CBP/p300 bromodomain inhibitor, suppresses human Th17 responses
Authors: Hammitzsch Ariane , Tallant Cynthia , Fedorov Oleg , O’Mahony Alison , Brennan Paul E. , Hay Duncan A. , Martinez Fernando O. , Al-Mossawi M. Hussein , de Wit Jelle , Vecellio Matteo , Wells Christopher , Wordsworth Paul , Müller Susanne , Knapp Stefan , Bowness Paul
Published: August 2015

Significance

Epigenetic inhibitors have shown considerable promise for the treatment of malignant and inflammatory diseases. We present here the detailed characterization of a potent and highly selective inhibitor of the bromodomains of CBP (CREB binding protein)/p300. Functional preclinical data studying cells derived from patients with ankylosing spondylitis and psoriatic arthritis (two human Th17-driven diseases) show that selective inhibition of the CBP/p300 bromodomain with CBP30 strongly reduces secretion of IL-17A, without having the broader and potentially deleterious effects on cytokine production and gene transcription of the pan-BET (bromo and extraterminal domain protein family) inhibitor JQ1. CBP/p300 play a significant role in IL-17A production, and CBP/p300 inhibition is a promising therapeutic strategy in human type-17–mediated diseases such as ankylosing spondylitis and psoriatic arthritis.
Microfluidic screening and whole-genome sequencing identifies mutations associated with improved protein secretion by yeast
Authors: Huang Mingtao , Bai Yunpeng , Sjostrom Staffan L. , Hallström Björn M. , Liu Zihe , Petranovic Dina , Uhlén Mathias , Joensson Haakan N. , Andersson-Svahn Helene , Nielsen Jens
Published: August 2015

Significance

Increasing demand for recombinant proteins leads to continuous attempts for improving the protein secretion capacity of host cells. In this study, we show that by combining high-throughput microfluidic screening with whole-genome sequencing of the selected clones from yeast libraries we can identify and map the mutations associated with significantly improved protein production. These identified mutations can be used as reverse metabolic engineering target genes in design of efficient cell factories for protein secretion. The mutations that we identified will also help in improving our understanding of the protein secretory mechanisms in yeast.
Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network
Authors: Shui Jianglan , Chen Chen , Grabstanowicz Lauren , Zhao Dan , Liu Di-Jia
Published: August 2015

Significance

The performance of conventional carbon-supported catalysts is strongly influenced by the support morphology, which contains micropores, mesopores, and macropores. Whereas micropores host the majority of the active sites and macropores promote effective reagent/product mass transfer, mesopores contribute a limited role in both but occupy a significant fraction of the total pore volume. For catalytic applications where maximizing active site number and mass/charge transports with the highest possible catalyst density is essential, conventional carbon supports are no longer suitable. In this paper, we introduce a previously unidentified catalyst’s morphology with a high catalytic active surface concentrated nearly exclusively in micropores while transferring reactant/product via a macroporous nanofiber framework. The nonprecious metal catalyst with such architecture demonstrated unprecedented activity in fuel cell tests.
Giving behavior of millionaires
Authors: Smeets Paul , Bauer Rob , Gneezy Uri
Published: August 2015

Significance

Wealthy individuals play an important role in charitable giving. We present evidence that millionaires give more than any other group studied in the literature. This holds particularly in a clear giving situation. In our study, millionaires either participated in a dictator game or an ultimatum game and they either interacted with another millionaire or with a low-income individual. In the dictator game, the millionaire decides how to split an amount between herself and a recipient who has no power. In the ultimatum game, the receiver needs to approve the proposer’s proposal; otherwise, both players are paid zero. Millionaires give more to a low-income participant in the dictator game than in the more strategic ultimatum game.
Genome-wide identification of CCA1 targets uncovers an expanded clock network inArabidopsis
Authors: Nagel Dawn H. , Doherty Colleen J. , Pruneda-Paz Jose L. , Schmitz Robert J. , Ecker Joseph R. , Kay Steve A.
Published: August 2015

Significance

The circadian clock, an endogenous time-keeping mechanism common to most species, allows organisms to coordinate biological processes with specific times of day. In plants, the role of the clock extends to almost every aspect of growth and development, including responses to biotic and abiotic stresses. The core molecular components and circuits of the clock have been well studied in the model organismArabidopsis thaliana; however, how this mechanism connects to clock-controlled outputs remains poorly understood. Here, we performed a genome-wide characterization of the direct targets of a key clock component inArabidopsis. Our results emphasize the broad role of the plant clock in regulating multiple biological functions and provide direct links between the oscillator and clock-regulated outputs.
T cell metabolism drives immunity
Authors: Buck Michael D. , O’Sullivan David , Pearce Erika L.
Published: August 2015

Lymphocytes must adapt to a wide array of environmental stressors as part of their normal development, during which they undergo a dramatic metabolic remodeling process. Research in this area has yielded surprising findings on the roles of diverse metabolic pathways and metabolites, which have been found to regulate lymphocyte signaling and influence differentiation, function and fate. In this review, we integrate the latest findings in the field to provide an up-to-date resource on lymphocyte metabolism.
Symmetry Reduction of the (2+1)-Dimensional Modified Dispersive Water-Wave System*
Authors: Ma Zheng-Yi , Fei Jin-Xi , Du Xiao-Yang
Published: August 2015

Using the standard truncated Painlevé expansion, the residual symmetry of the (2+1)-dimensional modified dispersive water-wave system is localized in the properly prolonged system with the Lie point symmetry vector. Some different transformation invariances are derived by utilizing the obtained symmetries. The symmetries of the system are also derived through the Clarkson–Kruskal direct method, and several types of explicit reduction solutions relate to the trigonometric or the hyperbolic functions are obtained. Finally, some special solitons are depicted from one of the solutions.
Colored Noises-Induced Regime Shifts in a Vegetation Ecological System*
Authors: Han Qing-Lin , Zeng Jia-Kui , Yang Tao , Zhang Chun , Long Fei , Fu Yun-Chang , Zeng Chun-Hua
Published: August 2015

In this paper, we investigate the stationary probability distribution and mean first passage time in a vegetation ecological system, which is driven by cross-correlation between intrinsic and extrinsic colored noises as well as the nonzero cross-correlation in between. The impacts of the self-correlation time τ1 and τ2, the cross-correlation time τ3 and intensity k on the stationary probability distribution and mean first passage time are discussed, respectively. Our main results show that: (i) the self-correlation time τ1 can induce regime shifts from the desert state to the sustainable vegetation state, while the self-correlation time τ2, cross-correlation time τ3 and intensity k can induce regime shifts from the sustainable vegetation state to the desert state; and (ii) the self-correlation time τ1 or τ2 can enhance the stability of the sustainable vegetation biomass, while the cross-correlation time τ3 or strength k weakens the stability of the sustainable vegetation biomass.