bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly(ionic liquid) Janus nanosheets towards dye degradation
Authors: Ji Xuyang , Zhang Qian , Qu Xiaozhong , Wang Qian , Song Xi-Ming , Liang Fuxin , Yang Zhenzhong
Published: February 2015

PW12O403− based PIL-Janus nanosheets are synthesised and employed as solid surfactants to stabilize emulsions and catalytically degrade water soluble dyes efficiently.
Enhancing the CO2 separation performance of composite membranes by the incorporation of amino acid-functionalized graphene oxide
Authors: Xin Qingping , Li Zhao , Li Congdi , Wang Shaofei , Jiang Zhongyi , Wu Hong , Zhang Yuan , Yang Jing , Cao Xingzhong
Published: February 2015

Amino acid-functionalized graphene oxide nanosheet-incorporated composite membranes significantly enhanced the CO2/CH4(N2) diffusivity, reactivity and solubility selectivities.
DFT study of Fe-Ni core-shell nanoparticles: Stability, catalytic activity, and interaction with carbon atom for single-walled carbon nanotube growth
Authors: Yang Zhimin , Wang Qiang , Shan Xiaoye , Li Wei-qi , Chen Guang-hui , Zhu Hongjun
Published: February 2015

Metal catalysts play an important role in the nucleation and growth of single-walled carbon nanotubes (SWCNTs). It is essential for probing the nucleation and growth mechanism of SWCNTs to fundamentally understand the properties of the metal catalysts and their interaction with carbon species. In this study, we systematically studied the stability of 13- and 55-atom Fe and Fe-Ni core-shell particles as well as these particles interaction with the carbon atoms using the density functional theory calculations. Icosahedral 13- and 55-atom Fe-Ni core-shell bimetallic particles have higher stability than the corresponding monometallic Fe and Ni particles. Opposite charge transfer (or distribution) in these particles leads to the Fe surface-shell displays a positive charge, while the Ni surface-shell exhibits a negative charge. The opposite charge transfer would induce different chemical activities. Compared with the monometallic Fe and Ni particles, the core-shell bimetallic particles have weaker interaction with C atoms. More importantly, C atoms only prefer staying on the surface of the bimetallic particles. In contrast, C atoms prefer locating into the subsurface of the monometallic particles, which is more likely to form stable metal carbides. The difference of the mono- and bimetallic particles on this issue may result in different nucleation and growth mechanism of SWCNTs. Our findings provide useful insights for the design of bimetallic catalysts and a better understanding nucleation and growth mechanism of SWCNTs.
Perturbations in vibrational diatomic spectra: Factorization of the molecular wave function
Authors: Lefebvre R.
Published: February 2015

The coupling between two electronic states of a diatomic molecule may lead to an erratic behaviour of the associated vibrational energies. An example is the homogeneous coupling between the valence b′ state and the Rydberg c′ state of the N2 molecule, both of symmetry 1Σu+. The standard treatment of such a situation is to write the wave function as a sum of two Born-Oppenheimer products. It has recently been argued [L. S. Cederbaum, J. Chem. Phys. 138, 224110 (2013); N. I. Gidopoulos and E. K. U. Gross, Philos. Trans. R. Soc., A 372, 20130059 (2014)] that even in such a case the wave function should be representable as a single product, with an electronic factor depending parametrically on nuclear positions and a nuclear factor. We setup such a representation in the case of the perturbations in the N2 molecule.
Chain rules for quantum Rényi entropies
Authors: Dupuis Frédéric
Published: February 2015

We present chain rules for a new definition of the quantum Rényi conditional entropy sometimes called the “sandwiched” Rényi conditional entropy. More precisely, we prove analogues of the equation H(AB|C) = H(A|BC) + H(B|C), which holds as an identity for the von Neumann conditional entropy. In the case of the Rényi entropy, this relation no longer holds as an equality but survives as an inequality of the form Hα(AB|C) ⩾ Hβ(A|BC) + Hγ(B|C), where the parameters α, β, γ obey the relation αα−1=ββ−1+γγ−1 and (α − 1)(β − 1)(γ − 1) > 1; if (α − 1)(β − 1)(γ − 1) < 1, the direction of the inequality is reversed.
Noether’s theorem for dissipative quantum dynamical semi-groups
Authors: Gough John E. , Ratiu Tudor S. , Smolyanov Oleg G.
Published: February 2015

Noether’s theorem on constants of the motion of dynamical systems has recently been extended to classical dissipative systems (Markovian semi-groups) by Baez and Fong [J. Math. Phys. 54, 013301 (2013)]. We show how to extend these results to the fully quantum setting of quantum Markov dynamics. For finite-dimensional Hilbert spaces, we construct a mapping from observables to completely positive maps that leads to the natural analogue of their criterion of commutativity with the infinitesimal generator of the Markov dynamics. Using standard results on the relaxation of states to equilibrium under quantum dynamical semi-groups, we are able to characterise the constants of the motion under quantum Markov evolutions in the infinite-dimensional setting under the usual assumption of existence of a stationary strictly positive density matrix. In particular, the Noether constants are identified with the fixed point of the Heisenberg picture semi-group.
Instability and associated roll structure of Marangoni convection in high Prandtl number liquid bridge with large aspect ratio
Authors: Yano T. , Nishino K. , Kawamura H. , Ueno I. , Matsumoto S.
Published: February 2015

This paper reports the experimental results on the instability and associated roll structures (RSs) of Marangoni convection in liquid bridges formed under the microgravity environment on the International Space Station. The geometry of interest is high aspect ratio (AR = height/diameter ≥ 1.0) liquid bridges of high Prandtl number fluids (Pr = 67 and 207) suspended between coaxial disks heated differentially. The unsteady flow field and associated RSs were revealed with the three-dimensional particle tracking velocimetry. It is found that the flow field after the onset of instability exhibits oscillations with azimuthal mode number m = 1 and associated RSs traveling in the axial direction. The RSs travel in the same direction as the surface flow (co-flow direction) for 1.00 ≤ AR ≤ 1.25 while they travel in the opposite direction (counter-flow direction) for AR ≥ 1.50, thus showing the change of traveling directions with AR. This traveling direction for AR ≥ 1.50 is reversed to the co-flow direction when the temperature difference between the disks is increased to the condition far beyond the critical one. This change of traveling directions is accompanied by the increase of the oscillation frequency. The characteristics of the RSs for AR ≥ 1.50, such as the azimuthal mode of oscillation, the dimensionless oscillation frequency, and the traveling direction, are in reasonable agreement with those of the previous sounding rocket experiment for AR = 2.50 and those of the linear stability analysis of an infinite liquid bridge.
Thermodynamics of fluid conduction through hydrophobic channel of carbon nanotubes: The exciting force for filling of nanotubes with polar and nonpolar fluids
Authors: Sahu Pooja , Ali Sk. M. , Shenoy K. T.
Published: February 2015

Thermodynamic properties of the fluid in the hydrophobic pores of nanotubes are known to be different not only from the bulk phase but also from other conventional confinements. Here, we use a recently developed theoretical scheme of “two phase thermodynamic (2PT)” model to understand the driving forces inclined to spontaneous filling of carbon nanotubes (CNTs) with polar (water) and nonpolar (methane) fluids. The CNT confinement is found to be energetically favorable for both water and methane, leading to their spontaneous filling inside CNT(6,6). For both the systems, the free energy of transfer from bulk to CNT confinement is favored by the increased entropy (TΔS), i.e., increased translational entropy and increased rotational entropy, which were found to be sufficiently high to conquer the unfavorable increase in enthalpy (ΔE) when they are transferred inside CNT. To the best of our knowledge, this is the first time when it has been established that the increase in translational entropy during confinement in CNT(6,6) is not unique to water-like H bonding fluid but is also observed in case of nonpolar fluids such as methane. The thermodynamic results are explained in terms of density, structural rigidity, and transport of fluid molecules inside CNT. The faster diffusion of methane over water in bulk phase is found to be reversed during the confinement in CNT(6,6). Studies reveal that though hydrogen bonding plays an important role in transport of water through CNT, but it is not the solitary driving factor, as the nonpolar fluids, which do not have any hydrogen bond formation capacity can go inside CNT and also can flow through it. The associated driving force for filling and transport of water and methane is enhanced translational and rotational entropies, which are attributed mainly by the strong correlation between confined fluid molecules and availability of more free space for rotation of molecule, i.e., lower density of fluid inside CNT due to their single file-like arrangement. To the best of our information, this is perhaps the first study of nonpolar fluid within CNT using 2PT method. Furthermore, the fast flow of polar fluid (water) over nonpolar fluid (methane) has been captured for the first time using molecular dynamic simulations.
Influence of the van der Waals interaction in the dissociation dynamics of N2 on W(110) from first principles
Authors: Martin-Gondre L. , Juaristi J. I. , Blanco-Rey M. , Díez Muiño R. , Alducin M.
Published: February 2015

Using ab initio molecular dynamics (AIMD) calculations, we investigate the role of the van der Waals (vdW) interaction in the dissociative adsorption of N2 on W(110). Hitherto, existing classical dynamics calculations performed on six-dimensional potential energy surfaces based on density functional theory (DFT), and the semi-local PW91 and RPBE [Hammer et al. Phys. Rev. B 59, 7413 (1999)] exchange-correlation functionals were unable to fully describe the dependence of the initial sticking coefficient on the molecular beam incidence conditions as found in experiments. N2 dissociation on W(110) was shown to be very sensitive not only to short molecule-surface distances but also to large distances where the vdW interaction, not included in semilocal-DFT, should dominate. In this work, we perform a systematic study on the dissociative adsorption using a selection of existing non-local functionals that include the vdW interaction (vdW-functionals). Clearly, the inclusion of the non-local correlation term contributes in all cases to correct the unrealistic energy barriers that were identified in the RPBE at large molecule-surface distances. Among the tested vdW-functionals, the original vdW-DF by Dion et al. [Phys. Rev. Lett. 92, 246401 (2004)] and the ulterior vdW-DF2 give also an adequate description of the N2 adsorption energy and energy barrier at the transition state, i.e., of the properties that are commonly used to verify the quality of any exchange-correlation functional. However, the results of our AIMD calculations, which are performed at different incidence conditions and hence extensively probe the multi-configurational potential energy surface of the system, do not seem as satisfactory as the preliminary static analysis suggested. When comparing the obtained dissociation probabilities with existing experimental data, none of the used vdW-functionals seems to provide altogether an adequate description of the N2/W(110) interaction at short and large distances.
On the Łojasiewicz exponent of Kuramoto model
Authors: Li Zhuchun , Xue Xiaoping , Yu Daren
Published: February 2015

The Łojasiewicz inequality and Łojasiewicz exponent reveal a fundamental relation between a potential function and its gradient. In this paper, we explore the Łojasiewicz exponent of Kuramoto model and prove that the exponent is exactly 12 for equilibria located inside a quarter of circle. This implies that the convergence towards such a phase-locked state must be exponentially fast. In contrast, we give an example to see the exponent can be less than 12 for other equilibriums. More precisely, we prove that the exponent for the bi-cluster equilibrium, which is located on the boundary of a quarter of circle, is 13. This gives an insight for the occurrence of exponential and algebraic convergence of Kuramoto model. We also present a general theorem for exponential convergence of second-order gradient-like system, by which a criterion for the Kuramoto model with inertia is established.
Integrability criterion in terms of coprime property for the discrete Toda equation
Authors: Kanki Masataka , Mada Jun , Tokihiro Tetsuji
Published: February 2015

We reformulate the singularity confinement, which is one of the most famous integrability criteria for discrete equations, in terms of the algebraic properties of the general terms of the discrete Toda equation. We show that the coprime property, which has been introduced in our previous paper as one of the integrability criteria, is appropriately formulated and proved for the discrete Toda equation. We study three types of boundary conditions (semi-infinite, molecule, periodic) for the discrete Toda equation, and prove that the same coprime property holds for all the types of boundaries.
Ground state energy of large polaron systems
Authors: Benguria Rafael D. , Frank Rupert L. , Lieb Elliott H.
Published: February 2015

The last unsolved problem about the many-polaron system, in the Pekar–Tomasevich approximation, is the case of bosons with the electron-electron Coulomb repulsion of strength exactly 1 (the “neutral case”). We prove that the ground state energy, for large N, goes exactly as −N7/5, and we give upper and lower bounds on the asymptotic coefficient that agree to within a factor of 22/5.
Emission mechanisms in Al-rich AlGaN/AlN quantum wells assessed by excitation power dependent photoluminescence spectroscopy
Authors: Iwata Yoshiya , Banal Ryan G. , Ichikawa Shuhei , Funato Mitsuru , Kawakami Yoichi
Published: February 2015

The optical properties of Al-rich AlGaN/AlN quantum wells are assessed by excitation-power-dependent time-integrated (TI) and time-resolved (TR) photoluminescence (PL) measurements. Two excitation sources, an optical parametric oscillator and the 4th harmonics of a Ti:sapphire laser, realize a wide range of excited carrier densities between 1012 and 1021 cm−3. The emission mechanisms change from an exciton to an electron-hole plasma as the excitation power increases. Accordingly, the PL decay time is drastically reduced, and the integrated PL intensities increase in the following order: linearly, super-linearly, linearly again, and sub-linearly. The observed results are well accounted for by rate equations that consider the saturation effect of non-radiative recombination processes. Using both TIPL and TRPL measurements allows the density of non-radiative recombination centers, the internal quantum efficiency, and the radiative recombination coefficient to be reliably extracted.
The role of the hole-extraction layer in determining the operational stability of a polycarbazole:fullerene bulk-heterojunction photovoltaic device
Authors: Bovill E. , Scarratt N. , Griffin J. , Yi H. , Iraqi A. , Buckley A. R. , Kingsley J. W. , Lidzey D. G.
Published: February 2015

We have made a comparative study of the relative operational stability of bulk-heterojunction organic photovoltaic (OPV) devices utilising different hole transport layers (HTLs). OPV devices were fabricated based on a blend of the polymer PCDTBT with the fullerene PC70BM, and incorporated the different HTL materials PEDOT:PSS, MoOx and V2O5. Following 620 h of irradiation by light from a solar simulator, we find that devices using the PEDOT:PSS HTL retained the highest efficiency, having a projected T80 lifetime of 14 500 h.
Triple-band perfect metamaterial absorption, based on single cut-wire bar
Authors: Yoo Y. J. , Kim Y. J. , Hwang J. S. , Rhee J. Y. , Kim K. W. , Kim Y. H. , Cheong H. , Chen L. Y. , Lee Y. P.
Published: February 2015

In general metamaterial perfect absorber, the single meta-pattern makes the single absorption band. Therefore, the multi-absorption bands need the corresponding kinds of meta-patterns. Here, we introduce the triple-band metamaterial perfect absorber utilizing only single kind of pattern. We also demonstrate the absorption mechanism of the triple perfect absorption. The first and the second absorption bands were induced by the fundamental magnetic resonance of the major and the minor axes, respectively, of cut-wire bar. The third peak was caused by the third-harmonic magnetic resonance of the major axis. Additionally, the unexpected third band was formed, which was the overlapping of the third absorption peak with another absorption peak, which was made by pairs of antiparallel currents parallel or antiparallel to the incident electromagnetic wave.
Nanotag-enabled photonic crystal fiber as quantitative surface-enhanced Raman scattering optofluidic platform
Authors: Pinkhasova Polina , Chen Hui , Kanka Jiri , Mergo Pawel , Du Henry
Published: February 2015

Core-shell nanotags that are active in surface-enhanced Raman scattering (SERS) and entrapped with thiocyanate (SCN) label molecules were immobilized in the air channels of suspended-core photonic crystal fiber (PCF) to impart quantitative capacity to SERS-based PCF optofluidic sensing platform. The Raman intensity of Rhodamine 6G increases with concentration, whereas the intensity of SCN remains constant when measured using this platform. The signal from the SCN label can be used as an internal reference to establish calibration for quantitative measurements of analytes of unknown concentrations. The long optical path-length PCF optofluidic platform integrated with SERS-active core-shell nanotags holds significant promise for sensitive quantitative chem/bio measurements with the added benefit of small sampling volume. The dependence of SERS intensity on the nanotag coverage density and PCF length was interpreted based on numerical-analytical simulations.
Laser ablation dynamics in liquid phase: The effects of magnetic field and electrolyte
Authors: Kim Kuk Ki , Roy Madhusudan , Kwon Hyejin , Song Jae Kyu , Park Seung Min
Published: February 2015

We examined the laser ablation dynamics of silver target in aqueous phase to explore the effects of laser power, ambient electrolytes, and magnetic field on the formation and expansion of laser-induced plasma plume, bubbles, and nanoparticles. The lifetime of the plasma emission increased with magnetic field and electrolytes, while they had no influence on the conversion of laser energy to the energy of laser-induced bubbles formed thereafter. The size of the bubbles was dependent only on the laser power.
Modeling study of mesh conductors and their electroluminescent devices
Authors: Hu Bin , Li Dapeng , Manandhar Prakash , Fan Qinguo , Kasilingam Dayalan , Calvert Paul
Published: February 2015

Numerical models were established to correlate with the experimentally measured properties of mesh conductors previously developed through a combined process of dip coating carbon nanotubes and inkjet printing poly 3,4-ethylenedioxythiophene: poly styrene sulfonate. The electroluminescent (EL) devices assembled with such mesh conductors as front electrodes were modeled by commercially available finite element method software COMSOL Multiphysics. The modeling results are in agreement with those from the experiments and suggest that an optimized fiber arrangement is the key for further improving the performance of EL devices based on mesh conductors.
Effect of creatine monohydrate supplementation on carcass traits, meat quality and postmortem energy metabolism of finishing pigs
Authors: Li J. L. , Guo Z. Y. , Li Y. J. , Zhang L. , Gao F. , Zhou G. H.
Published: February 2015

The objective of this study was to evaluate the effects of creatine monohydrate (CMH) supplementation on meat quality and postmortem energy metabolism of finishing pigs. In total, 48 healthy Duroc–Large White cross castrated male pigs were randomly allocated into two treatments, and fed either a CHM-free basal diet or a basal diet with CMH supplementation (0.8%) for 14 days. At the end of the experiment, six pigs from each treatment were weighed individually and slaughtered. The muscle from longissimus dorsi was collected to evaluate the meat quality and energy metabolism-related parameters. The results showed that CMH supplementation did not affect the loin eye area, back fat depth or dressing percentage (P > 0.05). The muscle pH45 min was higher, whereas drip loss and cooking loss were lower in the CMH supplementation group (P < 0.05). CMH supplementation increased the concentrations of creatine (P < 0.05), adenosine triphosphate (P < 0.05), adenosine diphosphate (P < 0.01) and creatine kinase activity (P < 0.05), and decreased the concentration of lactic acid (P < 0.05), and the activities of lactate dehydrogenase (P < 0.05) and pyruvate kinase (P < 0.05) in muscle postmortem. However, no differences were observed between groups for chemical composition, textural characteristics and glycolytic potential of longissimus dorsi muscle (P > 0.05). These findings suggest that dietary supplementation with CMH during the finishing period in pigs could delay early pH decline and decrease the rate of glycolysis in postmortem longissimus dorsi muscle resulting in a decreased drip loss.
Ancient dynamin segments capture early stages of host–mitochondrial integration
Authors: Purkanti Ramya , Thattai Mukund
Published: February 2015

Significance

Mitochondria were originally free-living bacteria with their own division machinery, which took up residence within another cell 2 billion y ago. The host cell subsequently tamed mitochondrial division using dynamin, a membrane-pinching protein. We have found that a single ancient dynamin at the root of extant eukaryotes, capable of pinching both mitochondria and vesicles, duplicated independently in plants and animals into specialized mitochondrial and vesicle variants. A “living fossil” of this ancient bifunctional dynamin still survives in scattered eukaryotic species, along with the original bacterial FtsZ division protein. The mitochondria of these organisms, preserved as if in amber, might teach us how the fateful partnership between host and endosymbiont was first established.
The fingerprint of climate trends on European crop yields
Authors: Moore Frances C. , Lobell David B.
Published: February 2015

Significance

Agriculture is one of the economic sectors most exposed to climate change impacts, but few studies have statistically connected long-term changes in temperature and rainfall with yields. Doing so in Europe is particularly important because yields of wheat and barley have plateaued since the early 1990s and climate change has been suggested as a cause of this stagnation. Here, we show that the impact of climate trends can be detected in the pattern of long-term yield trends in Europe. Although impacts have been large in some areas, the aggregate effect across the continent has been modest. Climate trends can explain 10% of the slowdown in wheat and barley yields, with changes in agriculture and environmental policies possibly responsible for the remainder.
Stress and telomere shortening among central Indian conservation refugees
Authors: Zahran Sammy , Snodgrass Jeffrey G. , Maranon David G. , Upadhyay Chakrapani , Granger Douglas A. , Bailey Susan M.
Published: February 2015

Significance

Recent research links life stress to premature telomere shortening and human aging. However, this association has only been demonstrated in Western contexts, where stress is typically lower and life expectancies longer. Using innovative approaches, we show significant associations between stress and telomere shortening in a non-Western setting among a highly stressed population with lower life expectancies: poor indigenous people—the Sahariya—who were displaced between 1998 and 2002 from their central Indian wildlife sanctuary homes. Our research strengthens the case for stress-induced telomere shortening as a pancultural biomarker of compromised health and aging.
Joint control of terrestrial gross primary productivity by plant phenology and physiology
Authors: Xia Jianyang , Niu Shuli , Ciais Philippe , Janssens Ivan A. , Chen Jiquan , Ammann Christof , Arain Altaf , Blanken Peter D. , Cescatti Alessandro , Bonal Damien , Buchmann Nina , Curtis Peter S. , Chen Shiping , Dong Jinwei , Flanagan Lawrence B. , Frankenberg Christian , Georgiadis Teodoro , Gough Christopher M. , Hui Dafeng , Kiely Gerard , Li Jianwei , Lund Magnus , Magliulo Vincenzo , Marcolla Barbara , Merbold Lutz , Montagnani Leonardo , Moors Eddy J. , Olesen Jørgen E. , Piao Shilong , Raschi Antonio , Roupsard Olivier , Suyker Andrew E. , Urbaniak Marek , Vaccari Francesco P. , Varlagin Andrej , Vesala Timo , Wilkinson Matthew , Weng Ensheng , Wohlfahrt Georg , Yan Liming , Luo Yiqi
Published: February 2015

Significance

Terrestrial gross primary productivity (GPP), the total photosynthetic CO
2
fixation at ecosystem level, fuels all life on land. However, its spatiotemporal variability is poorly understood, because GPP is determined by many processes related to plant phenology and physiological activities. In this study, we find that plant phenological and physiological properties can be integrated in a robust index—the product of the length of CO
2
uptake period and the seasonal maximal photosynthesis—to explain the GPP variability over space and time in response to climate extremes and during recovery after disturbance.
SK3 channel and mitochondrial ROS mediate NADPH oxidase-independent NETosis induced by calcium influx
Authors: Douda David Nobuhiro , Khan Meraj A. , Grasemann Hartmut , Palaniyar Nades
Published: February 2015

Significance

Formation of neutrophil extracellular traps (NETs) is a recently described process by which neutrophils combat microbial pathogens. Recent studies demonstrate causative relationships between NETs and debilitating disorders such as rheumatoid arthritis, vasculitis, thrombosis, cystic fibrosis, and acute respiratory distress syndrome. However, the understanding of signaling pathways governing the process termed “NETosis” remains elusive. Two major types of NETosis have been reported; however, the mechanistic differences between these two types are not clearly established. Here we describe that NETosis induced by calcium ionophores is fast, NADPH-oxidase independent, and is mediated by mitochondrial reactive oxygen species (ROS) and a calcium-activated small conductance potassium channel. Thus, drugs that target mitochondrial ROS production or the potassium channels may provide previously unidentified therapeutic approaches for combating disorders with unregulated NETosis.
β-Catenin in dendritic cells exerts opposite functions in cross-priming and maintenance of CD8+T cells through regulation of IL-10
Authors: Fu Chunmei , Liang Xinjun , Cui Weiguo , Ober-Blöbaum Julia L. , Vazzana Joseph , Shrikant Protul A. , Lee Kelvin P. , Clausen Björn E. , Mellman Ira , Jiang Aimin
Published: February 2015

Significance

While CD8+T cells are essential for antitumor immunity, tumors often evade CD8+T cell surveillance by immunosuppression. Recent study has shown that tumor-induced β-catenin activation in DCs suppresses CD8+T cell immunity by inhibiting cross-priming, suggesting that activation of β-catenin in DCs might be a key mechanism tumors use to achieve immunosuppression. This report identified mTOR/IL-10 signaling as a previously unidentified mechanism for β-catenin–dependent inhibition of cross-priming. Surprisingly, our study also revealed that β-catenin in DCs was required for CD8+T cell maintenance post-clonal expansion, suggesting that β-catenin exerts opposite functions during different stages of CD8+T cell responses. Based on these findings, we have demonstrated selectively manipulating β-catenin signaling as a feasible strategy to improve DC vaccine efficacy.
Redefining the role of Broca’s area in speech
Authors: Flinker Adeen , Korzeniewska Anna , Shestyuk Avgusta Y. , Franaszczuk Piotr J. , Dronkers Nina F. , Knight Robert T. , Crone Nathan E.
Published: February 2015

Significance

Broca’s area is widely recognized to be important for speech production, but its specific role in the dynamics of cortical language networks is largely unknown. Using direct cortical recordings of these dynamics during vocal repetition of written and spoken words, we found that Broca’s area mediates a cascade of activation from sensory representations of words in temporal cortex to their corresponding articulatory gestures in motor cortex, but it is surprisingly quiescent during articulation. Contrary to classic notions of this area’s role in speech, our results indicate that Broca’s area does not participate in production of individual words, but coordinates the transformation of information processing across large-scale cortical networks involved in spoken word production, prior to articulation.
Cells as liquid motors: Mechanosensitivity emerges from collective dynamics of actomyosin cortex
Authors: Étienne Jocelyn , Fouchard Jonathan , Mitrossilis Démosthène , Bufi Nathalie , Durand-Smet Pauline , Asnacios Atef
Published: February 2015

Significance

Animals have muscles to act on their environment. The molecules endowing them with this faculty are actin and myosin and are also present in nonmuscle cells. Our modelling breaks down the motor-like properties of the actomyosin network in single nonmuscle cells, which show striking similarity to the properties of muscles. In particular, an internal friction sets the maximum speed of contraction of both cells and muscles when myosins do not have time to detach after pulling, just as rowers lifting their oars too slowly after their stroke. The same modelling explains cell-scale mechanosensing: the combination of myosin-driven contraction and actin polymerization-driven protrusivity regulates cell length in a force-dependent manner, making response to rigidity a property of the very material of the cell cortex.
Late Pleistocene age and archaeological context for the hominin calvaria from GvJm-22 (Lukenya Hill, Kenya)
Authors: Tryon Christian A. , Crevecoeur Isabelle , Faith J. Tyler , Ekshtain Ravid , Nivens Joelle , Patterson David , Mbua Emma N. , Spoor Fred
Published: February 2015

Significance

Modern human (
Homo sapiens
) fossils from eastern African archaeological contexts from ∼70,000–20,000 years ago are rare, limiting our ability to understand the relationship between biological and behavioral change during a time and place characterized by major human demographic shifts, including dispersals. Our chronological, archaeological, and human paleontological analyses of the GvJm-22 rock shelter and Kenya National Museums Lukenya Hill Hominid 1 partial calvaria constrain the age of major behavioral changes among African foragers (the shift to Later Stone Age technologies) and demonstrate the morphological distinctness of Late Pleistocene African hominins from African Holocene or Late Pleistocene Eurasian hominins, complicating the history of modern human diversity.
In vivo NAD assay reveals the intracellular NAD contents and redox state in healthy human brain and their age dependences
Authors: Zhu Xiao-Hong , Lu Ming , Lee Byeong-Yeul , Ugurbil Kamil , Chen Wei
Published: February 2015

Significance

Decline in NAD
+
availability and abnormal NAD
+
/NADH redox state are tightly linked to age-related metabolic diseases and neurodegenerative disorders. To better understand the roles of NAD metabolism and redox state in health and disease, it is important to assess the intracellular NAD and redox state in situ. We report herein the first in vivo NAD assay, to our knowledge, that is capable of noninvasively and simultaneously measuring intracellular NAD
+
and NADH concentrations and NAD
+
/NADH ratio in the human brain and detecting the age-dependent changes in NAD contents and redox state associated with the normal aging. This method can potentially be applied to study various metabolic and neurodegenerative disorders by monitoring the NAD and redox state changes associated with disease progression or treatment in human patients.
Single-step fermentative production of the cholesterol-lowering drug pravastatin via reprogramming of
Penicillium chrysogenum
Authors: McLean Kirsty J. , Hans Marcus , Meijrink Ben , van Scheppingen Wibo B. , Vollebregt Aad , Tee Kang Lan , van der Laan Jan-Metske , Leys David , Munro Andrew W. , van den Berg Marco A.
Published: February 2015

Significance

Statins are successful widely used drugs that decrease the risk of coronary heart disease and strokes by lowering cholesterol levels. They selectively inhibit the key regulatory enzyme of the cholesterol synthesis pathway, thus lowering levels of plasma LDL (bad) cholesterol. Pravastatin is one of the leading and most effective statins, derived from the natural product compactin. However, pravastatin production involves a costly dual-step fermentation and biotransformation process. Here we present a single-step fermentative method for production of the active drug pravastatin. Reprogramming of the antibiotics-producing fungus
Penicillium chrysogenum
, with discovery and engineering of an enzyme involved in the hydroxylation of compactin, enables high level fermentation of the correct form of pravastatin to facilitate efficient industrial-scale statin drug production.
In vitro reconstitution of indolmycin biosynthesis reveals the molecular basis of oxazolinone assembly
Authors: Du Yi-Ling , Alkhalaf Lona M. , Ryan Katherine S.
Published: February 2015

Significance

Resistance to current antibiotics is rising worldwide, and replacement molecules are urgently needed. The tryptophanyl–tRNA synthetase inhibitor indolmycin, containing a unique oxazolinone core, was first isolated in 1960, but the molecular basis for its construction is still unknown. Here we report the complete pathway to indolmycin, using a combination of genetic and biochemical approaches. Our work reveals how the oxazolinone core is assembled by the dual action of the ATP-dependent enzyme Ind3, and Ind6, an unusual gatekeeper protein. Our work sets the stage for generating improved microbial production systems for indolmycin and for development of indolmycin-like antibiotics.
Increasing propensity to mind-wander with transcranial direct current stimulation
Authors: Axelrod Vadim , Rees Geraint , Lavidor Michal , Bar Moshe
Published: February 2015

Significance

Mind wandering is a spontaneous and self-generated behavior believed to be important for many mental functions, including creativity and future planning. Can the propensity to mind-wander be modulated externally? If so, this observation would mean that directly modifying spontaneous neural activity can change internally directed thought. To answer this question, we used noninvasive transcranial direct current stimulation (tDCS) to stimulate the prefrontal cortex. Our results showed, for the first time to our knowledge, that mind wandering, probably the most omnipresent internal cognitive function, can be enhanced by external stimulation. In addition, we showed that the frontal lobes play a causal role in mind wandering. We furthermore suggest that the executive control system, and specifically the dorsolateral prefrontal cortex, might play an important role in mind-wandering behavior.
Replicative fitness of transmitted HIV-1 drives acute immune activation, proviral load in memory CD4
+
T cells, and disease progression
Authors: Claiborne Daniel T. , Prince Jessica L. , Scully Eileen , Macharia Gladys , Micci Luca , Lawson Benton , Kopycinski Jakub , Deymier Martin J. , Vanderford Thomas H. , Nganou-Makamdop Krystelle , Ende Zachary , Brooks Kelsie , Tang Jianming , Yu Tianwei , Lakhi Shabir , Kilembe William , Silvestri Guido , Douek Daniel , Goepfert Paul A. , Price Matthew A. , Allen Susan A. , Paiardini Mirko , Altfeld Marcus , Gilmour Jill , Hunter Eric
Published: February 2015

Significance

HIV infection is associated with elevated inflammation and aberrant cellular immune activation. Indeed, the activation status of an HIV-infected individual is often more predictive of disease trajectory than viral load. Here, we highlight the importance of the replicative fitness of the transmitted viral variant in driving an early inflammatory state, characterized by T-cell activation and immune dysfunction. This impact on T-cell homeostasis is independent of protective host immune response genes and viral load. Highly replicating transmitted variants were also significantly more efficient at infecting memory CD4
+
T cells, a population important for maintaining the latent viral reservoir. Together, these data provide a mechanism whereby viral replicative fitness acts as a major determinant of disease progression and persistence.
Moth tails divert bat attack: Evolution of acoustic deflection
Authors: Barber Jesse R. , Leavell Brian C. , Keener Adam L. , Breinholt Jesse W. , Chadwell Brad A. , McClure Christopher J. W. , Hill Geena M. , Kawahara Akito Y.
Published: February 2015

Significance

Bats and moths have been engaged in acoustic warfare for more than 60 million y. Yet almost half of moth species lack bat-detecting ears and still face intense bat predation. We hypothesized that the long tails of one group of seemingly defenseless moths, saturniids, are an anti-bat strategy designed to divert bat attacks. Using high-speed infrared videography, we show that the spinning hindwing tails of luna moths lure echolocating bat attacks to these nonessential appendages in over half of bat–moth interactions. Further we show that long hindwing tails have independently evolved multiple times in saturniid moths. This finding expands our knowledge of antipredator deflection strategies, the limitations of bat sonar, and the extent of a long-standing evolutionary arms race.
Human trypanolytic factor APOL1 forms pH-gated cation-selective channels in planar lipid bilayers: Relevance to trypanosome lysis
Authors: Thomson Russell , Finkelstein Alan
Published: February 2015

Significance

African trypanosomes are parasites that can cause African sleeping sickness in humans. Host defense against some of these is provided by the human serum factor apolipoprotein L-1 (APOL1), which causes swelling and lysis of susceptible trypanosomes. Lysis follows uptake of APOL1 into acidic parasite endosomes and is thought to involve ion influx across the plasma membrane. In this paper we show that, after interaction of APOL1 with lipid bilayers at acidic pH, subsequent pH neutralization triggers the opening of pH-gated channels that selectively conduct cations across the bilayer. Based on these results, we propose a mechanism of trypanosome lysis that involves endocytic recycling of APOL1 and the opening of APOL1-induced cation-selective channels, at neutral pH, in the parasite plasma membrane.
Floral organ abscission is regulated by a positive feedback loop
Authors: Patharkar O. Rahul , Walker John C.
Published: February 2015

Significance

Dramatic changes in gene expression occur in abscission zones immediately prior to abscission. This study helps explain the mechanisms and emergent properties of a regulatory network that controls abscission. Two important connections are made that help explain the observed dynamic range of abscission gene expression. First, it connects a MAP kinase cascade that positively regulates abscission to a MADS-domain transcription factor, AGAMOUS-like 15 (AGL15). Second, it connects AGL15 to the expression of a receptor kinase known to control abscission. All together, the findings define a positive feedback loop that provides exponential signal amplification that starts with a receptor, goes through a MAP kinase cascade and a transcription factor, and then returns to the receptor.
Capillary-bridge–derived particles with negative Gaussian curvature
Authors: Wang Liming , McCarthy Thomas J.
Published: February 2015

Significance

Particles find use in a plethora of applications that range from cosmetics to electrically conducting adhesives. They can be composed of different substances, vary in size, and have different shapes such as spheres and rods. The surfaces of particles are almost universally convex (positive Gaussian curvature) for the same reason that liquid forms a sphere in air. A drop of liquid spanning two surfaces, however, forms an hourglass-shaped capillary bridge with concave curvature in the dimension that spans the two surfaces. In this article, we show that capillary bridges of monomers can be polymerized to prepare hourglass-shaped particles with negative Gaussian curvature. Particles with this shape have not yet been studied.
Mutant
IDH
is sufficient to initiate enchondromatosis in mice
Authors: Hirata Makoto , Sasaki Masato , Cairns Rob A. , Inoue Satoshi , Puviindran Vijitha , Li Wanda Y. , Snow Bryan E. , Jones Lisa D. , Wei Qingxia , Sato Shingo , Tang Yuning J. , Nadesan Puviindran , Rockel Jason , Whetstone Heather , Poon Raymond , Weng Angela , Gross Stefan , Straley Kimberly , Gliser Camelia , Xu Yingxia , Wunder Jay , Mak Tak W. , Alman Benjamin A.
Published: February 2015

Significance

Current genomic and biochemical analysis revealed mutations in
isocitrate dehydrogenase
(
IDH
) genes associated with several neoplasms and a novel enzymatic activity of IDH mutations to catalyze α-ketoglutarate to
d
-2-hydroxyglutarate, contributing to tumorigenesis. We identified a broad range of
IDH1
mutations, including a previously unidentified
IDH1
-R132Q mutation, in cartilage tumors. Cartilage-specific Col2a1-Cre/ERT2;Idh1-R132 mutant knock-in mice developed multiple enchondroma-like lesions. These data show that mutant Idh in growth-plate cells causes persistence of chondrocytes, giving rise to enchondromas adjacent to the growth cartilage in bone.
Insect capa neuropeptides impact desiccation and cold tolerance
Authors: Terhzaz Selim , Teets Nicholas M. , Cabrero Pablo , Henderson Louise , Ritchie Michael G. , Nachman Ronald J. , Dow Julian A. T. , Denlinger David L. , Davies Shireen-A.
Published: February 2015

Significance

Insects are among the most robust organisms on the planet, surviving in virtually all environments and capable of surmounting a range of environmental stresses including desiccation and cold. Although desiccation and cold tolerance share many common traits, potential mechanisms for such linked responses remain unclear. Here we show that an insect neuropeptide gene is associated with tolerance of both desiccation and cold in
Drosophila melanogaster
, suggesting a novel mechanism in renal tubule epithelia that enhances survival of both desiccation and cold. Also, we can reverse RNAi-induced stress tolerance phenotypes in intact flies using rationally designed peptide mimetic analogs. We thus demonstrate the power of intervention in physiological processes controlled by neuropeptides, with potential for insect pest control.
On assigning pragmatic functions in English
Authors: Mackenzie J. Lachlan , Keizer Evelien
Published: February 2015

This paper presents a discussion of the treatment of the pragmatic functions Topic and Focus in Functional Grammar (Dik: 1989, ch. 13). Two questions will be addressed: (a) the theoretical question of how the interface between the static grammar (dealing with a discourse as the product of text-creating activity) and the dynamic theory of verbal interaction (dealing with discourse as the ongoing text-creating process itself) is handled with regard to pragmatic functions; and (b) the practical question whether the reader of Dik (1989) finds a set of proposals that can be operationalized in the analysis of linguistic material. With regard to the former question we conclude that in the present FG treatment of Topic and Focus, the static and the dynamic approaches do not connect and that, as a result, the speaker’s selection of constituents for Topic or Focus function is left unaccounted for. As for the second question, we show that Dik’s proposal can be put into practice, but that the resultant analysis suffers from a number of inconsistencies and unclarities. Finally, we argue that most of these inconsistencies and unclarities can be solved if (1) we accept a different classification of Focus, and (2) assume that Topic assignment is irrelevant in English, as there is no consistent way in which Topic constituents are given special treatment, and Pl-placement can be accounted for without having to resort to Topic function.
Social/interactional functions of code switching among Dominican Americans
Authors: Bailey Benjamin
Published: February 2015

Linguistic assumptions of an individual speaker-hearer are subtly reflected in analyses of code switching that assign switches to “conversational strategies,” categories that are treated as if they existed prior to, and independent of, actual interactions. While such categories provide convenient rubrics for many common and significant social functions of code switching, they fail to capture the interactionally emergent functions of many switches. In this article I highlight such locally emergent functions of code switching among Dominican American high school students by examining several transcripts of intra-group, peer interaction from a conversation analytic perspective. Many switches in such peer interaction are better explained in terms of the sequential, conversational management activities achieved by interlocutors than by pre-defined categories of switches.
The tabloid talkshow as a quasi-conversational type of face-to-face interaction
Authors: Gregori-Signes Carmen
Published: February 2015

Media discourse, and in particular programmes such as talkshows, are certainly practices that have extended, enriched, and often taken to the limits, conversation as a speech event. The number of possibilities arising from conversational practice have certainly found a new dimension in the context of the mass media, and on TV in particular (cf. Vande Berg et al. 1991 and 1998). In this article I describe tabloid talkshows as one type of speech event. I focus on the description of the turn-taking organisation in tabloid talkshows by comparing their characteristics to those outlined by Sacks et al. (1974) for conversation. In order to carry out such comparison, I first propose a review and, consequently, a reform of the 14 features listed by Sacks et al. in their article ‘A simplest systematics for the organization of turn-taking in conversation’. The results show that there are differences between both types of interaction.
On the Spanish inferential construction ser que
Authors: Delahunty Gerald P. , Gatzkiewicz Laura
Published: February 2015

Spanish (along with English and many other languages) has inferential sentences such as No es que no quiera: Es que no sabe querer, ‘It’s not that she doesn’t love; it’s that she doesn’t know how to love.’ We describe the grammar and pragmatics of these sentences and show how their pragmatic characteristics follow from their grammar and the principles of relevance theory. Inferentials consist of a finite clause embedded as the complement of an expletive copular matrix clause, which may be modified by a focusing particle and/or a negator. Inferentials function as metalinguistic devices which characterize the relevance of the proposition represented by their clause to the processing of an utterance. Negative inferentials characterize that proposition as likely to be considered in the processing but they deny its relevance; positive inferentials characterize the proposition as unlikely to be considered but they assert its relevance. The inferential proposition may be interpreted as an implicated premise or conclusion. If it is taken as an implicated premise then it may be further interpreted as an explanation, reason, or cause; if it is taken as an implicated conclusion then it may be further interpreted as a result, consequence, or conclusion. It may also be taken as a (re)interpretation or reformulation of the target utterance.