bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of residual stress on photoluminescence in multi-crystalline silicon wafers
Authors: Pogue Vanessa , Melkote Shreyes N. , Rounsaville Brian , Danyluk Steven
Published: February 2017

This paper presents the results of an experiment designed to understand the effect of manufacturing-induced residual stress on photoluminescence (PL) in multi-crystalline silicon (mc-Si) wafers used for photovoltaic applications. The experiment relies on the use of near-infrared birefringence polariscopy and polarized micro-Raman spectroscopy to measure casting-induced residual stress present in mc-Si wafers. High temperature annealing was used to relieve the residual stress in the mc-Si wafers, and photoluminescence was used to evaluate the electrical performance to provide a correlation of residual stress to electrical activity. High temperature annealing produced a drastic improvement in photoluminescence. A decrease in the number of points of highest maximum shear stress correlated with an increase in photoluminescence. Additionally, a direct correlation was found between higher tensile residual stress and increased PL.
Antiferromagnetic interlayer exchange coupling in all-perovskite La0.7Sr0.3MnO3/SrRu1-xTixO3 superlattices
Authors: Xu Haoran , Wan Siyuan , Chen Binbin , Ma Chao , Jin Feng , Guo Zhuang , Lan Da , Chen Feng , Wu Wenbin
Published: February 2017

An unambiguous antiferromagnetic interlayer exchange coupling (IEC) is realized in all-perovskite oxide La0.7Sr0.3MnO3(LSMO)/SrRu1-xTixO3(SR1-xTxO) (x < 0.3) superlattices above the Curie temperature of the SR1-xTxO spacer layer, which is different from the traditional interfacial antiferromagnetic coupling. For 0.3 ≤ x ≤ 0.5, the superlattices behave as a ferromagnetic coupling. Meanwhile, this antiferromagnetic IEC between the ferromagnetic LSMO layers across the SR1-xTxO spacer can be further modulated by changing the thickness of SR1-xTxO spacer. Combining the high Curie temperature of LSMO, these findings may have potential applications in future spintronic devices.
Hopf bifurcation in a nonlocal nonlinear transport equation stemming from stochastic neural dynamics
Authors: Drogoul Audric , Veltz Romain
Published: February 2017

In this work, we provide three different numerical evidences for the occurrence of a Hopf bifurcation in a recently derived [De Masi et al., J. Stat. Phys. 158, 866–902 (2015) and Fournier and löcherbach, Ann. Inst. H. Poincaré Probab. Stat. 52, 1844–1876 (2016)] mean field limit of a stochastic network of excitatory spiking neurons. The mean field limit is a challenging nonlocal nonlinear transport equation with boundary conditions. The first evidence relies on the computation of the spectrum of the linearized equation. The second stems from the simulation of the full mean field. Finally, the last evidence comes from the simulation of the network for a large number of neurons. We provide a “recipe” to find such bifurcation which nicely complements the works in De Masi et al. [J. Stat. Phys. 158, 866–902 (2015)] and Fournier and löcherbach [Ann. Inst. H. Poincaré Probab. Stat. 52, 1844–1876 (2016)]. This suggests in return to revisit theoretically these mean field equations from a dynamical point of view. Finally, this work shows how the noise level impacts the transition from asynchronous activity to partial synchronization in excitatory globally pulse-coupled networks.
Dynamics of vector dark solitons propagation and tunneling effect in the variable coefficient coupled nonlinear Schrödinger equation
Authors: Musammil N. M. , Porsezian K. , Subha P. A. , Nithyanandan K.
Published: February 2017

We investigate the dynamics of vector dark solitons propagation using variable coefficient coupled nonlinear Schrödinger (Vc-CNLS) equation. The dark soliton propagation and evolution dynamics in the inhomogeneous system are studied analytically by employing the Hirota bilinear method. It is apparent from our asymptotic analysis that the collision between the dark solitons is elastic in nature. The various inhomogeneous effects on the evolution and interaction between dark solitons are explored, with a particular emphasis on nonlinear tunneling. It is found that the tunneling of the soliton depends on a condition related to the height of the barrier and the amplitude of the soliton. The intensity of the tunneling soliton either forms a peak or a valley, thus retaining its shape after tunneling. For the case of exponential background, the soliton tends to compress after tunneling through the barrier/well. Thus, a comprehensive study of dark soliton pulse evolution and propagation dynamics in Vc-CNLS equation is presented in the paper.
Time-resolved photoelectron imaging with a femtosecond vacuum-ultraviolet light source: Dynamics in the A∼/B∼- and F∼-bands of SO2
Authors: Svoboda Vít , Ram Niraghatam Bhargava , Rajeev Rajendran , Wörner Hans Jakob
Published: February 2017

Time-resolved photoelectron imaging is demonstrated using the third harmonic of a 400-nm femtosecond laser pulse as the ionization source. The resulting 133-nm pulses are combined with 266-nm pulses to study the excited-state dynamics in the A∼/B∼- and F∼-band regions of SO2. The photoelectron signal from the molecules excited to the A∼/B∼-band does not decay for at least several picoseconds, reflecting the population of bound states. The temporal variation of the photoelectron angular distribution (PAD) reflects the creation of a rotational wave packet in the excited state. In contrast, the photoelectron signal from molecules excited to the F∼-band decays with a time constant of 80 fs. This time constant is attributed to the motion of the excited-state wave packet out of the ionization window. The observed time-dependent PADs are consistent with the F∼ band corresponding to a Rydberg state of dominant s character. These results establish low-order harmonic generation as a promising tool for time-resolved photoelectron imaging of the excited-state dynamics of molecules, simultaneously giving access to low-lying electronic states, as well as Rydberg states, and avoiding the ionization of unexcited molecules.
Optimization of numerical orbitals using the Helmholtz kernel
Authors: Solala Eelis , Losilla Sergio A. , Sundholm Dage , Xu Wenhua , Parkkinen Pauli
Published: February 2017

We present an integration scheme for optimizing the orbitals in numerical electronic structure calculations on general molecules. The orbital optimization is performed by integrating the Helmholtz kernel in the double bubble and cube basis, where bubbles represent the steep part of the functions in the vicinity of the nuclei, whereas the remaining cube part is expanded on an equidistant three-dimensional grid. The bubbles’ part is treated by using one-center expansions of the Helmholtz kernel in spherical harmonics multiplied with modified spherical Bessel functions of the first and second kinds. The angular part of the bubble functions can be integrated analytically, whereas the radial part is integrated numerically. The cube part is integrated using a similar method as we previously implemented for numerically integrating two-electron potentials. The behavior of the integrand of the auxiliary dimension introduced by the integral transformation of the Helmholtz kernel has also been investigated. The correctness of the implementation has been checked by performing Hartree-Fock self-consistent-field calculations on H2, H2O, and CO. The obtained energies are compared with reference values in the literature showing that an accuracy of 10−4 to 10−7 Eh can be obtained with our approach.
Resonant magnetization switching conditions of an exchange-coupled bilayer under spin wave excitation
Authors: Zhou W. , Yamaji T. , Seki T. , Imamura H. , Takanashi K.
Published: February 2017

We systematically investigated spin wave-assisted magnetization switching (SWAS) of a L10-FePt/Ni81Fe19 (permalloy; Py) exchange-coupled bilayer by using a pulse-like rf field (hrf) and mapped the switching events in the magnetic field (H)–hrf frequency (f) plane in order to reveal the switching conditions. Switching occurred only in a limited region followed by the dispersion relationship of the perpendicular standing spin wave modes in the Py. The results indicate that SWAS is a resonant magnetization switching process, which is different from the conventional microwave assisted switching and has the potential to be used for selective switching in multilevel recording media.
Electromigration failure mode concerning negative resistance shift of Cu interconnects buried in porous low-k dielectric
Authors: Zheng Hui , Yin Binfeng , Yu Hewei , Chen Leigang , Gao Lin , Zhou Ke , Kuo Chinte
Published: February 2017

Electromigration failure mode concerning a negative resistance shift of 4%–11% and cathode burnout was reported for Cu interconnects buried in porous low-k in this paper. Evidence for oxidation and debonding of Ta/TaN liner at high temperature was revealed, which was demonstrated to have been enabled by the unsealed porous low-k due to moisture uptake. The cathode burnout was thus attributed to severe Joule heating induced in the insulated liner after oxidation. The resistance decay of Cu also exhibited to be mainly consistent with the calculation from specularity recovery of electron scattering at the Cu/Ta interface after oxidation and debonding of the liner, although other factors like strain relaxation may also have some contribution.
Comprehensive biocompatibility of nontoxic and high-output flexible energy
harvester using lead-free piezoceramic thin film
Authors: Jeong Chang Kyu , Han Jae Hyun , Palneedi Haribabu , Park Hyewon , Hwang Geon-Tae , Joung Boyoung , Kim Seong-Gon , Shin Hong Ju , Kang Il-Suk , Ryu Jungho , Lee Keon Jae
Published: February 2017

Flexible piezoelectric energy harvesters have been regarded as an overarching candidate for achieving self-powered electronic systems for environmental sensors and biomedical devices using the self-sufficient electrical energy. In this research, we realize a flexible high-output and lead-free piezoelectric energy harvester by using the aerosol deposition method and the laser lift-off process. We also investigated the comprehensive biocompatibility of the lead-free piezoceramic device using ex-vivo ionic elusion and in vivo bioimplantation, as well as in vitro cell proliferation and histologic inspection. The fabricated LiNbO3-doped (K,Na)NbO3 (KNN) thin film-based flexible energy harvester exhibited an outstanding piezoresponse, and average output performance of an open-circuit voltage of ∼130 V and a short-circuit current of ∼1.3 μA under normal bending and release deformation, which is the best record among previously reported flexible lead-free piezoelectric energy harvesters. Although both the KNN and Pb(Zr,Ti)O3 (PZT) devices showed short-term biocompatibility in cellular and histological studies, excessive Pb toxic ions were eluted from the PZT in human serum and tap water. Moreover, the KNN-based flexible energy harvester was implanted into a porcine chest and generated up to ∼5 V and 700 nA from the heartbeat motion, comparable to the output of previously reported lead-based flexible energy harvesters. This work can compellingly serve to advance the development of piezoelectric energy harvesting for actual and practical biocompatible self-powered biomedical applications beyond restrictions of lead-based materials in long-term physiological and clinical aspects.
Collective effect of personal behavior induced preventive measures and differential rate of transmission on spread of epidemics
Authors: Sagar Vikram , Zhao Yi
Published: February 2017

In the present work, the effect of personal behavior induced preventive measures is studied on the spread of epidemics over scale free networks that are characterized by the differential rate of disease transmission. The role of personal behavior induced preventive measures is parameterized in terms of variable λ, which modulates the number of concurrent contacts a node makes with the fraction of its neighboring nodes. The dynamics of the disease is described by a non-linear Susceptible Infected Susceptible model based upon the discrete time Markov Chain method. The network mean field approach is generalized to account for the effect of non-linear coupling between the aforementioned factors on the collective dynamics of nodes. The upper bound estimates of the disease outbreak threshold obtained from the mean field theory are found to be in good agreement with the corresponding non-linear stochastic model. From the results of parametric study, it is shown that the epidemic size has inverse dependence on the preventive measures (λ). It has also been shown that the increase in the average degree of the nodes lowers the time of spread and enhances the size of epidemics.
Offshore wind power atlas of the Black Sea Region
Authors: Aydoğan Burak
Published: February 2017

This study presents an offshore wind power density atlas of the Black Sea Region, including the Black Sea, the Sea of Azov, and the Sea of Marmara, by taking variable air density into account as a function of temperature, pressure, and water content. ECMWF ERA-Interim Reanalysis data spanned over 37 years have been analyzed and monthly average wind speeds, wind speed Weibull scale, and shape parameters, air density, wind power, and operational percentages were presented in the form of maps for 50 m of altitude. Cumulative wind power density frequency maps were generated for 6 percentiles. It is found out that the monthly mean air density has an annual variation of about 9%, which directly affects the available wind power. Results show that the wind power density in the region increases in the West and the North directions, having the maximum potential at the North-West part of the Black Sea and the Sea of Azov. The power density at these locations can be classified as class 4 wind power according to the classification defined by the U.S. Department of Energy.
Communication: Low-energy free-electron driven molecular engineering: In situ preparation of intrinsically short-lived carbon-carbon covalent dimer of CO
Authors: Davis Daly , Sajeev Y.
Published: February 2017

Molecular modification induced through the resonant attachment of a low energy electron (LEE) is a novel approach for molecular engineering. In this communication, we explore the possibility to use the LEE as a quantum tool for the in situ preparation of short lived molecules. Using ab initio quantum chemical methods, this possibility is best illustrated for the in situ preparation of the intrinsically short-lived carbon-carbon covalent dimer of CO from a glyoxal molecule. The chemical conversion of glyoxal to the covalent dimer of CO is initiated and driven by the resonant capture of a near 11 eV electron by the glyoxal molecule. The resulting two-particle one-hole (2p-1h) negative ion resonant state (NIRS) of the glyoxal molecule undergoes a barrierless radical dehydrogenation reaction and produces the covalent dimer of CO. The autoionization electron spectra from the 2p-1h NIRS at the dissociation limit of the dehydrogenation reaction provides access to the electronic states of the CO dimer. The overall process is an example of a catalytic electron reaction channel.
Observation of convection phenomenon by high-performance transparent heater based on Pt-decorated Ni micromesh
Authors: Kim Han-Jung , Kim Dong-Ik , Kim Sam-Soo , Kim Young-You , Park Sung-Eun , Choi Gyuseok , Lee Dong Wook , Kim Yoonkap
Published: February 2017

In this study, we report for the first time on the convection phenomenon for the consistent and sensitive detection of target materials (particulate matter (PM) or gases) with a high-performance transparent heater. The high-performance transparent heater, based on Pt-decorated Ni micromesh, was fabricated by a combination of transfer printing process and Pt sputtering. The resulting transparent heater exhibited excellent mechanical durability, adhesion with substrates, flexibility, and heat-generating performance. We monitored the changes in the PM concentration and temperature in an airtight chamber while operating the heater. The temperature in the chamber was increased slightly, and the PM2.5 concentration was increased by approximately 50 times relative to the initial state which PM is deposed in the chamber. We anticipate that our experimental findings will aid in the development and application of heaters for sensors and actuators as well as transparent electrodes and heating devices.
Influence of the artificial surface dielectric layer on domain patterning by ion beam in MgO-doped lithium niobate single crystals
Authors: Chezganov D. S. , Shur V. Ya. , Vlasov E. O. , Gimadeeva L. V. , Alikin D. O. , Akhmatkhanov A. R. , Chuvakova M. A. , Mikhailovskii V. Yu.
Published: February 2017

We experimentally compared the shapes and sizes of isolated domains created by the focused ion beam irradiation in the lithium niobate crystals doped by MgO with polar surface covered by dielectric (resist) layer and those with free surface. We attributed the larger sizes of isolated domains in the samples covered by the resist layer to ion localization in the resist. We revealed a change in the domain shape as a function of increasing dose and explained it in terms of kinetic approach taking into account the modification of the surface layers by ion irradiation. We applied the obtained knowledge for 1D and 2D periodical poling using ion beam. Finally, we created the 2D square 1-μm-period array of isolated domains with radius about 300 nm and maximal depth of all domains in the array up to 100 μm as well as the 1D pattern of through stripe domains with 2-μm-period in 1-mm-thick wafer.
Developing general acoustic model for noise sources and parameters estimation
Authors: Madoliat Reza , Nouri Nowrouz Mohammad , Rahrovi Ali
Published: February 2017

Noise measured at various points around the environment can be evaluated by a series of acoustic sources. Acoustic sources with wide surface can be broken down in fluid environment using some smaller acoustic sources. The aim of this study is to make a model to indicate the type, number, direction, position and strength of these sources in a way that the main sound and the sound of equivalent sources match together in an acceptable way. When position and direction of the source is given, the strength of the source can be found using inverse method. On the other hand, considering the non-uniqueness of solution in inverse method, a different acoustic strength is obtained for the sources if different positions are selected. Selecting an arrangement of general source and using the optimization algorithm, the least possible mismatch between the main sound and the sound of equivalent sources can be achieved.
Improving ruminal fermentation and nutrient digestibility in dairy steers by banana flower powder-pellet supplementation
Authors: Kang Sungchhang , Wanapat Metha
Published: February 2017

The present study aimed to investigate the effect of banana flower powder pellet (BAFLOP pellet) on nutrient digestibility, rumen ecology and microorganism population. Four rumen-fistulated dairy steers of 200 ± 20 kg bodyweight were randomly assigned to receive four dietary treatments according to a 4 × 4 Latin square design. The treatments were as follows: control (T1), NaHCO3 supplementation at 20 g/kg of total dry-matter feed intake (DMI; T2), BAFLOP-pellet supplementation at 20 g/kg of DMI (T3) and BAFLOP-pellet supplementation at 40 g/kg of DMI (T4). All cattle were fed roughage–concentrate mix (30 : 70 ratio) at 25 g/kg bodyweight. Standard management protocols were employed during the experimental periods. The results showed that nutrient digestibility was increased in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI (P < 0.05). Although ruminal temperature and blood urea nitrogen were not influenced by dietary supplementation, ruminal pH was increased (P < 0.05) in steers supplemented with NaHCO3 and BAFLOP pellets at 40 g/kg DMI. In addition, NaHCO3 supplementation increased bacterial and protozoal populations, whereas populations of fungal zoospores were similar among treatments. Supplementation with BAFLOP pellets at 40 g/kg DMI increased the bacterial count, whereas protozoal numbers were similar to those in the control group (P < 0.05). On the basis of the present findings, BAFLOP-pellet supplementation improved nutrient digestibility, ruminal pH and microbial population, without having any adverse effects on voluntary feed intake. The present study showed promising results for BAFLOP pellets (40 g/kg DMI) as a rumen dietary buffering agent, suggesting that these pellets could be used a replacement for sodium bicarbonate in ruminants fed high-concentrate diets.
Consequences of phloem pathway unloading/reloading on equilibrium flows between source and sink: a modelling approach
Authors: Minchin Peter E. H. , Lacointe André
Published: February 2017

It is now accepted that the transport phloem, linking major sources and sinks, is leaky, and this leakage can be considerable. Hence for phloem transport to function over the long distances observed, a large fraction of this unloaded photosynthate must be reloaded. A fraction of this unloaded solute is used to maintain tissues surrounding the phloem, as well as being stored. Also, pathway unloading/reloading acts as a short-term buffer to source and sink changes. In this work we present the first attempt to include both pathway unloading and reloading of carbohydrate in the modelling of pressure driven flow to determine if this has any significant effect upon source–sink dynamics. Our results indicated that the flow does not follow Poiseuille dynamics, and that pathway unloading alters the solute concentration and hydrostatic pressure profiles. Hence, measurement of either of these without considerable other detail tells us very little about the flow mechanisms. With adequate reloading along the pathway, the effects of pathway unloading can completely compensate for, making the entire system look like one with no pathway unloading.
Social–ecological network analysis of scale mismatches in estuary watershed restoration
Authors: Sayles Jesse S. , Baggio Jacopo A.
Published: February 2017

Significance

Spatial misalignments between governance and environmental systems, often called spatial scale mismatch, are a key sustainability challenge. Collaboration and coordination networks can help overcome scale mismatch problems and should align with the environmental system. Using an approach based on network science, this paper advances scale mismatch analysis by explicitly considering collaborations among local and regional organizations doing estuary watershed restoration (i.e., multilevel governance) and how these collaborations align with environmental patterns. Collaboration quality is considered to inform network-based theories for natural resource governance. Integrating network analysis results with ecological habitat data further provides a social–environmental restoration planning perspective. This research can help policymakers allocate resources and is a fundamental step toward addressing scale mismatch while considering multilevel governance.
A network perspective reveals decreasing material diversity in studies on nanoparticle interactions with dissolved organic matter
Authors: Sani-Kast Nicole , Labille Jérôme , Ollivier Patrick , Slomberg Danielle , Hungerbühler Konrad , Scheringer Martin
Published: February 2017

Significance

Understanding the environmental fate of engineered nanoparticles (ENPs) is essential to the risk assessment of nanotechnology. Dissolved organic matter (DOM) strongly influences the behavior of ENPs in aqueous systems. This influence depends on many factors and, in particular, the types of ENPs and DOM. Accordingly, recent reviews have called repeatedly to expand the range of DOM and ENPs studied. Here, we use a network perspective to assess, in terms of the material types studied, the current state of research into DOM–ENP interactions. We identify global tendencies in the choice of materials and experimental approaches that have contributed to an undesirable discrepancy between the ever-increasing number of published experiments and the persisting call for investigation of more material types.
Structural basis of jasmonate-amido synthetase FIN219 in complex with glutathione S-transferase FIP1 during the JA signal regulation
Authors: Chen Chun-Yen , Ho Sih-Syun , Kuo Tzu-Yen , Hsieh Hsu-Liang , Cheng Yi-Sheng
Published: February 2017

Significance

Far-red (FR) insensitive 219 (FIN219) is the main jasmonate (JA)-amido synthetase that activates the systemic synthesis of bioactive JAs in
Arabidopsis
. FIN219 is involved in FR light signaling and interacts with another signaling component, FIN219-interacting protein 1 (FIP1). To extend our understanding of the regulatory mechanism between FR light signaling and the JA response, we determine the crystal structures of the FIN219–FIP1 complex with substrates and show that interaction with FIP1 triggers enhanced activity of FIN219. FIN219 conformational changes driven by FIP1 are observed in the C-terminal domain and show a relatively occluded form of the active site. By measuring the FIN219–FIP1 interaction and adenylation function, this study reveals that FIP1 may regulate FIN219 activity and further alters the level of JA signaling.
Seasonal prediction of US summertime ozone using statistical analysis of large scale climate patterns
Authors: Shen Lu , Mickley Loretta J.
Published: February 2017

Significance

This study identifies the relationship between summertime ozone air quality in the eastern United States and large-scale meteorological patterns, including sea surface temperature (SST) patterns and teleconnections, evolving over the preceding months. We show that this relationship can be used in spring to predict ozone for the following summer. Our work implies that large-scale phenomena such as the Atlantic Multidecadal Oscillation may drive multidecadal variability in US ozone air quality. We find in particular that springtime tropical Atlantic SSTs have a significant influence on summertime meteorology and ozone air quality in the eastern United States, but the free-running, atmosphere-only climate models with prescribed SSTs fail to capture these seasonally evolving teleconnections.
Selenium deficiency risk predicted to increase under future climate change
Authors: Jones Gerrad D. , Droz Boris , Greve Peter , Gottschalk Pia , Poffet Deyan , McGrath Steve P. , Seneviratne Sonia I. , Smith Pete , Winkel Lenny H. E.
Published: February 2017

Significance

The trace element selenium is essential for human health and is required in a narrow dietary concentration range. Insufficient selenium intake has been estimated to affect up to 1 billion people worldwide. Dietary selenium availability is controlled by soil–plant interactions, but the mechanisms governing its broad-scale soil distributions are largely unknown. Using data-mining techniques, we modeled recent (1980–1999) distributions and identified climate–soil interactions as main controlling factors. Furthermore, using moderate climate change projections, we predicted future (2080–2099) soil selenium losses from 58% of modeled areas (mean loss = 8.4%). Predicted losses from croplands were even higher, with 66% of croplands predicted to lose 8.7% selenium. These losses could increase the worldwide prevalence of selenium deficiency.
Sustained disruption of narwhal habitat use and behavior in the presence of Arctic killer whales
Authors: Breed Greg A. , Matthews Cory J. D. , Marcoux Marianne , Higdon Jeff W. , LeBlanc Bernard , Petersen Stephen D. , Orr Jack , Reinhart Natalie R. , Ferguson Steven H.
Published: February 2017

Significance

Predators are widely understood to impact the structure and stability of ecosystems. In the Arctic, summer sea ice is rapidly declining, degrading habitat for Arctic species, such as polar bears and ringed seals, but also providing more access to important predators, such as killer whales. Using data from concurrently tracked predator (killer whales) and prey (narwhal), we show that the presence of killer whales significantly changes the behavior and distribution of narwhal. Because killer whales are effective predators of many marine mammals, similar predator-induced changes would be expected in the behavior of tracked animals in marine ecosystems worldwide. However, these effects are rarely considered and may frequently go unrecognized.
Designing allostery-inspired response in mechanical networks
Authors: Rocks Jason W. , Pashine Nidhi , Bischofberger Irmgard , Goodrich Carl P. , Liu Andrea J. , Nagel Sidney R.
Published: February 2017

Significance

We show that removal of a small number of bonds in a random elastic network can dramatically change its mechanical response. Our theoretical approach precisely and efficiently controls the local strain at one point in such a network in response to a strain applied elsewhere in the system. The responses we create are inspired by the long-range-correlated deformations that often characterize allostery in proteins. The ubiquity of allostery in biological molecules suggests that it is relatively easy to develop through evolution. Our nearly 100% success rate in designing these responses by removing a very small fraction of bonds shows that it is similarly easy to create these types of elastic responses in disordered mechanical networks.
Giant ripples on comet 67P/Churyumov–Gerasimenko sculpted by sunset thermal wind
Authors: Jia Pan , Andreotti Bruno , Claudin Philippe
Published: February 2017

Significance

The recent approach to comet 67P/Churyumov–Gerasimenko by the spacecraft Rosetta has revealed the presence of astonishing dune-like patterns. How can the radial outgassing, caused by heating when passing close to the sun, produce a vapor flow along the surface of the comet dense enough to transport grains? Drawing on the physical mechanisms at work for the formation of dunes on Earth and planetary bodies, we quantitatively explain the emergence and size of these bedforms, which are due to thermal winds. This work involves the understanding of the comet surface processes, especially regarding grain cohesion and grain–fluid interaction. It thus provides more keys to address the timely open question on the growth of planetesimals above the meter scale to form planets.
Biosynthetic pathway of aliphatic formates via a Baeyer–Villiger oxidation in mechanism present in astigmatid mites
Authors: Shimizu Nobuhiro , Sakata Daisuke , Schmelz Eric A. , Mori Naoki , Kuwahara Yasumasa
Published: February 2017

Significance

Aliphatic formates are commonly detected in astigmatid mite secretions and have been considered for roles in pheromone communication. Despite the natural occurrence of aliphatic formates, details surrounding the biosynthetic pathways remain unclear. To probe the biosynthetic mechanism, we performed
13
C-incorporation experiments targeting two different chain-like aliphatic formates by feeding with suitable labeled precursors. Results support a mechanism whereby formates are generated via the Baeyer–Villiger oxidation of aldehydes as direct precursors. The enzyme that catalyzes this reaction has yet to be identified in animals, microbes, and plants. Results from the labeling studies inform approaches to identify the specific gene and encoded enzyme responsible for aliphatic formate biosynthesis, which will enable a facile dehomologation method in the field of organic synthesis.
Real space renormalization group theory of disordered models of glasses
Authors: Angelini Maria Chiara , Biroli Giulio
Published: February 2017

Significance

The hallmark of the glass transition is the very fast increase of the relaxation time

τ
α

. Experimental results have rationalized this fact in terms of a growing effective activation energy scale,

Δ

=

T

log
⁡

τ
α

, characterizing the height of the barriers in the rough energy landscape of glass-forming liquids. By applying the renormalization group method to disordered models of glasses, we show that barriers related to degrees of freedom correlated on the scale

ℓ

as

ℓ
θ

, where

θ

is a critical exponent. The growth of the static length-scale

ξ

, which is the typical size of the statically correlated regions, thus leads to

Δ

∼

ξ
θ

and provides a general explanation for glassy behavior.
In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures
Authors: Cain Stuart M. , Bohnet Barry , LeDue Jeffrey , Yung Andrew C. , Garcia Esperanza , Tyson John R. , Alles Sascha R. A. , Han Huili , van den Maagdenberg Arn M. J. M. , Kozlowski Piotr , MacVicar Brian A. , Snutch Terrance P.
Published: February 2017

Significance

Spreading depression is proposed to underlie migraine with aura, a type of debilitating headache for which few pharmacological treatments are available. The pain drug pregabalin has demonstrated initial promising results for the treatment of migraine in the clinic. Utilizing animal models of congenital migraine and live brain imaging, we describe the cortical and subcortical migration of the spreading depression wave. Further, pregabalin is shown to be effective at suppressing spreading depression initiation, wave speed, and subcortical propagation, and also to affect nerve cell signalling directly. Overall, the study supports the therapeutic potential of pregabalin in both noncongenital migraineurs and patients with mild congenital migraine.
Light-driven growth in Amazon evergreen forests explained by seasonal variations of vertical canopy structure
Authors: Tang Hao , Dubayah Ralph
Published: February 2017

Significance

Observations of field experiments and satellite imagery have led to a significant debate about light-driven growth of Amazon forests during the dry season. We help resolve these conflicts using observations from spaceborne lidar, and show that both canopy and understory have an opportunistic ecological response to the radiation and moisture regimes. Our research is placed within a consistent ecological framework that links gap theory, field-based studies, and the remote-sensing data record, and which illuminates mechanistic responses of the understory and canopy forming trees to changes in light and water.
Crystal structure of
Aquifex aeolicus
σ
N
bound to promoter DNA and the structure of σ
N
-holoenzyme
Authors: Campbell Elizabeth A. , Kamath Shreya , Rajashankar Kanagalaghatta R. , Wu Mengyu , Darst Seth A.
Published: February 2017

Significance

The bacterial σ factors confer promoter specificity to the RNA polymerase (RNAP). One σ factor, σ
N
, is unique in its structure and functional mechanism, forming transcriptionally inactive promoter complexes with RNAP that require activation by specialized ATPases. The structural basis for σ
N
function is of great interest but poorly understood. Here, we determined an X-ray crystal structure of a σ
N
fragment bound to promoter DNA, revealing the molecular details of promoter recognition by σ
N
. Moreover, the new structure allowed us to build and refine a corrected σ
N
-holoenzyme (σ
N
/RNAP complex) model using previously published X-ray data. This work overall provides a solid structural framework with which to address further the poorly understood mechanism of activator function in ATP hydrolysis-dependent promoter opening.
Secretagogin-dependent matrix metalloprotease-2 release from neurons regulates neuroblast migration
Authors: Hanics János , Szodorai Edit , Tortoriello Giuseppe , Malenczyk Katarzyna , Keimpema Erik , Lubec Gert , Hevesi Zsófia , Lutz Mirjam I. , Kozsurek Márk , Puskár Zita , Tóth Zsuzsanna E. , Wagner Ludwig , Kovács Gábor G. , Hökfelt Tomas G. M. , Harkany Tibor , Alpár Alán
Published: February 2017

Significance

Persisting proliferative capacity and regeneration in the adult brain are confined to a minority of regions. In the murine brain, the olfactory system is supplied by thousands of newly born neuroblasts daily to support sensory plasticity. Here, we reveal a neuronal scaffold that resides within and alongside this migratory route [termed the “rostral migratory stream” (RMS)] to guide forward migration of newly born neuroblasts. These neurons can externalize the enzyme matrix metalloprotease-2 to loosen the extracellular matrix, thus producing permissive corridors for migrating neuroblasts. This mechanism is likely phylogenetically conserved because it exists in the RMS equivalent in human fetal brains. This inducible mechanism might be pharmacologically targeted for therapeutic benefit.
Effects of Common Angler Handling Techniques on Florida Largemouth Bass Behavior, Feeding, and Survival
Authors: Skaggs Jordan , Quintana Yasmín , Shaw Stephanie L. , Allen Micheal S. , Trippel Nicholas A. , Matthews Michael
Published: February 2017

Black bass Micropterus spp. support popular freshwater sport fisheries in North America. Bass anglers commonly adopt catch and release as a conservation practice, and frequently over 75% of angled black bass are released back into the water. If fish survive the angling event, the practice of catch and release as an alternative to harvest reduces direct mortality, but it has the potential to affect the postrelease feeding behavior and survival of the fish. The act of lifting black bass for handling, hook removal, and photograph opportunities may cause stress and injury, and the degree of injury sustained could be influenced by fish size. Holding fish in a tilted grip by the jaw has raised concern among anglers about potential damage to jaw musculature and tendons, as they may not support the fish's body weight out of water, particularly for trophy bass. We conducted an experiment with Florida Largemouth Bass M. salmoides floridanus to evaluate the relative differences in survival, jaw mechanics, and feeding success after the use of three common handling treatments: (1) a vertical hold using a lip-grip device (vertical treatment); (2) a tilted, one-handed grip using only the lower jaw (horizontal treatment); and (3) two-handed support to the lower jaw and body (support treatment). The time taken by fish to regain equilibrium and resume normal swimming behavior after handling differed among the three treatments; the recovery period was shortest for fish in the support treatment (mean ± SD = 7 ± 10 s; vertical treatment: 33 ± 74 s; horizontal treatment: 12 ± 16 s). Minor injuries (e.g., abrasions and sores) and diseases (e.g., tumors and fungus) tended to increase after handling across the entire sample. Results suggested no evidence of handling-specific differences in fish feeding behavior, jaw adjustments, and mortality after release. However, based on our results, we recommend that anglers use two-handed support to handle Florida Largemouth Bass, thus minimizing the mean amount of time for an individual fish to regain equilibrium after an angling event.

Received February 22, 2016; accepted October 7, 2016 Published online February 22, 2017
TOPBP1Dpb11 plays a conserved role in homologous recombination DNA repair through the coordinated recruitment of 53BP1Rad9
Authors: Liu Yi , Cussiol José Renato , Dibitetto Diego , Sims Jennie Rae , Twayana Shyam , Weiss Robert Samuel , Freire Raimundo , Marini Federica , Pellicioli Achille , Smolka Marcus Bustamante
Published: February 2017

Genome maintenance and cancer suppression require homologous recombination (HR) DNA repair. In yeast and mammals, the scaffold protein TOPBP1Dpb11 has been implicated in HR, although its precise function and mechanism of action remain elusive. In this study, we show that yeast Dpb11 plays an antagonistic role in recombination control through regulated protein interactions. Dpb11 mediates opposing roles in DNA end resection by coordinating both the stabilization and exclusion of Rad9 from DNA lesions. The Mec1 kinase promotes the pro-resection function of Dpb11 by mediating its interaction with the Slx4 scaffold. Human TOPBP1Dpb11 engages in interactions with the anti-resection factor 53BP1 and the pro-resection factor BRCA1, suggesting that TOPBP1 also mediates opposing functions in HR control. Hyperstabilization of the 53BP1–TOPBP1 interaction enhances the recruitment of 53BP1 to nuclear foci in the S phase, resulting in impaired HR and the accumulation of chromosomal aberrations. Our results support a model in which TOPBP1Dpb11 plays a conserved role in mediating a phosphoregulated circuitry for the control of recombinational DNA repair.
Improving mechanical properties of carbon nanotube fibers through simultaneous solid-state cycloaddition and crosslinking
Authors: Lu Xinyi , Hiremath Nitilaksha , Hong Kunlun , Evora Maria C , Ranson Victoria H , Naskar Amit K , Bhat Gajanan S , Kang Nam-Goo , Mays Jimmy W
Published: February 2017

Individual carbon nanotubes (CNTs) exhibit exceptional mechanical properties. However, difficulties remain in fully realizing these properties in CNT macro-assemblies, because the weak inter-tube forces result in the CNTs sliding past one another. Herein, a simple solid-state reaction is presented that enhances the mechanical properties of carbon nanotube fibers (CNTFs) through simultaneous covalent functionalization and crosslinking. This is the first chemical crosslinking proposed without the involvement of a catalyst or byproducts. The specific tensile strength of CNTFs obtained from the treatment employing a benzocyclobutene-based polymer is improved by 40%. Such improvement can be attributed to a reduced number of voids, impregnation of the polymer, and the formation of covalent crosslinks. This methodology is confirmed using both multiwalled nanotube (MWNT) powders and CNTFs. Thermogravimetric analysis, differential scanning calorimetry, x-ray photoelectron spectroscopy, and transmission electron microscopy of the treated MWNT powders confirm the covalent functionalization and formation of inter-tube crosslinks. This simple one-step reaction can be applied to industrial-scale production of high-strength CNTFs.
Role of scavenger receptors as damage-associated molecular pattern receptors in Toll-like receptor activation
Authors: Komai Kyoko , Shichita Takashi , Ito Minako , Kanamori Mitsuhiro , Chikuma Shunsuke , Yoshimura Akihiko
Published: February 2017

Damage-associated molecular patterns (DAMPs) have been implicated in sterile inflammation in various tissue injuries. High-mobility group box 1 (HMGB1) is a representative DAMP, and has been shown to transmit signals through receptors for advanced glycation end products (RAGEs) and TLRs, including TLR2 and TLR4. HMGB1 does not, however, bind to TLRs with high affinity; therefore, the mechanism of HMGB1-mediated TLR activation remains unclear. In this study, we found that fluorescently labeled HMGB1 was efficiently internalized into macrophages through class A scavenger receptors. Although both M1- and M2-type macrophages internalized HMGB1, only M1-type macrophages secreted cytokines in response to HMGB1. The pan-class A scavenger receptor competitive inhibitor, maleylated bovine serum albumin (M-BSA), inhibited HMGB1 internalization and reduced cytokine production from macrophages in response to HMGB1 but not to LPS. The C-terminal acidic domain of HMGB1 is responsible for scavenger receptor-mediated internalization and cytokine production. HMGB1 and TLR4 co-localized in macrophages, and this interaction was disrupted by M-BSA, suggesting that class A scavenger receptors function as co-receptors of HMGB1 for TLR activation. M-BSA ameliorated LPS-induced sepsis and dextran sulfate sodium (DSS)-induced colitis models in which HMGB1 has been shown to play progressive roles. These data suggest that scavenger receptors function as co-receptors along with TLRs for HMGB1 in M1-type inflammatory macrophages.
Catering to Investors Through Security Design: Headline Rate and Complexity*
Authors: Célérier Claire , Vallée Boris
Published: February 2017

This study investigates how banks design financial products to cater to yield-seeking investors. We focus on a large market of investment products targeted exclusively at households: retail structured products. These products typically offer a high return under their best-case scenario—the headline rate—that is nested in a complex payoff formula. Using a text analysis of the payoff formulas of the 55,000 products issued in Europe from 2002 to 2010, we measure product headline rates, complexity, and risk. Over this period, product headline rates depart from the prevailing interest rates as the latter decrease, complexity increases, and risky products become more common. In the cross section, the headline rate of a product is positively correlated with its level of complexity and risk. Higher headline rate, more complex, and riskier products appear more profitable to the banks distributing them. Our results suggest that financial complexity is a by-product of banks catering to yield-seeking investors.
Recognizing age-related macular degeneration in primary care
Authors: Cunningham Jill
Published: February 2017

Age-related macular degeneration (AMD) is a disabling condition that results in central vision loss and significantly affects the quality of life for the growing population of older adults. Primary care providers play a vital role in early recognition of disease. This article reviews the risk factors, symptoms, physical examination findings, and management of AMD. Although there is no cure at this time, early referral and treatment may prevent some patients from progressing to complete vision loss.
Update on asthma and cleaning agents
Authors: Folletti Ilenia , Siracusa Andrea , Paolocci Giulia
Published: February 2017

Purpose of review

Asthma due to cleaning products has been known for 20 years, and the interest in this topic is still large because of the number of cleaning workers with respiratory problems. In this review, we sought to highlight the most recent findings on the relationship between exposure to cleaning products and asthma and to summarize the specific literature published between 2013 and 2016.

Recent findings

Women are confirmed as most of workers exposed to cleaning products and have a higher frequency than men of work-related respiratory symptoms and diseases. Many cases of asthma due to cleaning products occur in healthcare occupations. The increased risk of asthma has been shown to be related to the number of years in the job and to early life disadvantage. Recent evidence suggests that predisposition to adult-onset asthma may be related to interaction between genes and occupational exposure to low-molecular weight agents/irritants. There is some evidence that an irritant mechanism is more common, although several case reports showed animmunologic mechanism (e.g. disinfectants, amine compounds, aldehydes and fragrances).

The review updated recent findings on epidemiology, cleaning agents and their mechanism, and prevention of asthma due to cleaning agents. This article provides new information on the level of exposure, which is still high in professional cleaners and even more in domestic cleaners, and on the frequency of asthma in professional and domestic cleaners. An irritant mechanism is more common, although an immunological mechanism is possible, especially in healthcare workers exposed to disinfectants.
Neuroanesthesiology Update
Authors: Pasternak Jeffrey J. , Lanier William L.
Published: February 2017

We reviewed manuscripts published in 2016 that are related to the care of neurosurgical patients or the perioperative care of patients with neurological diseases. We address the broad categories of general neurosurgery and neuroanesthesiology, anesthetic neurotoxicity and neuroprotection, stroke, traumatic brain injury, and nervous system monitoring.