bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic dispensers for thermoplasmonic control of alkali vapor pressure in quantum optical applications
Authors: Rusimova Kristina R. , Slavov Dimitar , Pradaux-Caggiano Fabienne , Collins Joel T. , Gordeev Sergey N. , Carbery David R. , Wadsworth William J. , Mosley Peter J. , Valev Ventsislav K. 
Published: May 2019

AbstractAlkali metal vapors enable access to single electron systems, suitable for demonstrating fundamental light-matter interactions and promising for quantum logic operations, storage and sensing. However, progress is hampered by the need for robust and repeatable control over the atomic vapor density and over the associated optical depth. Until now, a moderate improvement of the optical depth was attainable through bulk heating or laser desorption – both time-consuming techniques. Here, we use plasmonic nanoparticles to convert light into localized thermal energy and to achieve optical depths in warm vapors, corresponding to a ~16 times increase in vapor pressure in less than 20 ms, with possible reload times much shorter than an hour. Our results enable robust and compact light-matter devices, such as efficient quantum memories and photon-photon logic gates, in which strong optical nonlinearities are crucial.
Atomic resolution cryo-EM structure of a native-like CENP-A nucleosome aided by an antibody fragment
Authors: Zhou Bing-Rui , Yadav K. N. Sathish , Borgnia Mario , Hong Jingjun , Cao Baohua , Olins Ada L. , Olins Donald E. , Bai Yawen , Zhang Ping 
Published: May 2019

AbstractGenomic DNA in eukaryotes is organized into chromatin through association with core histones to form nucleosomes, each distinguished by their DNA sequences and histone variants. Here, we used a single-chain antibody fragment (scFv) derived from the anti-nucleosome antibody mAb PL2-6 to stabilize human CENP-A nucleosome containing a native α-satellite DNA and solved its structure by the cryo-electron microscopy (cryo-EM) to 2.6 Å resolution. In comparison, the corresponding cryo-EM structure of the free CENP-A nucleosome could only reach 3.4 Å resolution. We find that scFv binds to a conserved acidic patch on the histone H2A-H2B dimer without perturbing the nucleosome structure. Our results provide an atomic resolution cryo-EM structure of a nucleosome and insight into the structure and function of the CENP-A nucleosome. The scFv approach is applicable to the structural determination of other native-like nucleosomes with distinct DNA sequences.
Direct dioxygen evolution in collisions of carbon dioxide with surfaces
Authors: Yao Yunxi , Shushkov Philip , Miller Thomas F. , Giapis Konstantinos P. 
Published: May 2019

AbstractThe intramolecular conversion of CO2 to molecular oxygen is an exotic reaction, rarely observed even with extreme optical or electronic excitation means. Here we show that this reaction occurs readily when CO2 ions scatter from solid surfaces in a two-step sequential collision process at hyperthermal incidence energies. The produced O2 is preferentially ionized by charge transfer from the surface over the predominant atomic oxygen product, leading to direct detection of both O2+ and O2−. First-principles simulations of the collisional dynamics reveal that O2 production proceeds via strongly-bent CO2 configurations, without visiting other intermediates. Bent CO2 provides dynamic access to the symmetric dissociation of CO2 to C+O2 with a calculated yield of 1 to 2% depending on molecular orientation. This unexpected collision-induced transformation of individual CO2 molecules provides an accessible pathway for generating O2 in astrophysical environments and may inspire plasma-driven electro- and photo-catalytic strategies for terrestrial CO2 reduction.
The stability of multitrophic communities under habitat loss
Authors: McWilliams Chris , Lurgi Miguel , Montoya Jose M. , Sauve Alix , Montoya Daniel 
Published: May 2019

AbstractHabitat loss (HL) affects species and their interactions, ultimately altering community dynamics. Yet, a challenge for community ecology is to understand how communities with multiple interaction types—hybrid communities—respond to HL prior to species extinctions. To this end, we develop a model to investigate the response of hybrid terrestrial communities to two types of HL: random and contiguous. Our model reveals changes in stability—temporal variability in population abundances—that are dependent on the spatial configuration of HL. Our findings highlight that habitat area determines the variability of populations via changes in the distribution of species interaction strengths. The divergent responses of communities to random and contiguous HL result from different constraints imposed on individuals’ mobility, impacting diversity and network structure in the random case, and destabilising communities by increasing interaction strength in the contiguous case. Analysis of intermediate HL suggests a gradual transition between the two extreme cases.
Hong-Ou-Mandel interferometry on a biphoton beat note
Authors: Chen Yuanyuan , Fink Matthias , Steinlechner Fabian , Torres Juan P. , Ursin Rupert 
Published: May 2019

AbstractHong-Ou-Mandel interference, the fact that identical photons that arrive simultaneously on different input ports of a beam splitter bunch into a common output port, can be used to measure optical delays between different paths. It is generally assumed that great precision in the measurement requires that photons contain many frequencies, i.e., a large bandwidth. Here we challenge this “well-known” assumption and show that the use of two well-separated frequencies embedded in a quantum entangled state (discrete color entanglement) suffices to achieve great precision. We determine optimum working points using a Fisher Information analysis and demonstrate the experimental feasibility of this approach by detecting thermally-induced delays in an optical fiber. These results may significantly facilitate the use of quantum interference for quantum sensing, by avoiding some stringent conditions such as the requirement for large bandwidth signals.
Possible Male Infanticide in Wild Orangutans and a Re-evaluation of Infanticide Risk
Authors: Knott Cheryl D. , Scott Amy M. , O’Connell Caitlin A. , Scott Katherine S. , Laman Timothy G. , Riyandi  , Susanto Tri Wahyu 
Published: May 2019

AbstractInfanticide as a male reproductive tactic is widespread across mammals, and is particularly prevalent in catarrhine primates. While it has never been observed in wild orangutans, infanticide by non-sire males has been predicted to occur due to their extremely long inter-birth intervals, semi-solitary social structure, and the presence of female counter-tactics to infanticide. Here, we report on the disappearance of a healthy four-month-old infant, along with a serious foot injury suffered by the primiparous mother. No other cases of infant mortality have been observed at this site in 30 years of study. Using photographic measurements of the injury, and information on the behavior and bite size of potential predators, we evaluate the possible causes of this injury. The context, including the behavior of the female and the presence of a new male at the time of the injury, lead us to conclude that the most likely cause of the infant loss and maternal injury was male infanticide. We suggest that in orangutans, and other species where nulliparous females are not preferred mates, these females may be less successful at using paternity confusion as an infanticide avoidance tactic, thus increasing the likelihood of infanticide of their first-born infants.
Bifurcation and Pattern Symmetry Selection in Reaction-Diffusion Systems with Kinetic Anisotropy
Authors: Gao Yipeng , Zhang Yongfeng , Schwen Daniel , Jiang Chao , Gan Jian 
Published: May 2019

AbstractOrdering and self-organization are critical in determining the dynamics of reaction-diffusion systems. Here we show a unique pattern formation mechanism, dictated by the coupling of thermodynamic instability and kinetic anisotropy. Intrinsically different from the physical origin of Turing instability and patterning, the ordered patterns we obtained are caused by the interplay of the instability from uphill diffusion, the symmetry breaking from anisotropic diffusion, and the reactions. To understand the formation of the void/gas bubble superlattices in crystals under irradiation, we establish a general theoretical framework to predict the symmetry selection of superlattice structures associated with anisotropic diffusion. Through analytical study and phase field simulations, we found that the symmetry of a superlattice is determined by the coupling of diffusion anisotropy and the reaction rate, which indicates a new type of bifurcation phenomenon. Our discovery suggests a means for designing target experiments to tailor different microstructural patterns.
Highly stretchable graphene nanoribbon springs by programmable nanowire lithography
Authors: Liu Chuan , Yao Bing , Dong Taige , Ma Haiguang , Zhang Shaobo , Wang Junzhuan , Xu Jun , Shi Yi , Chen Kunji , Gao Libo , Yu Linwei 
Published: May 2019

AbstractGraphene nanoribbons are ideal candidates to serve as highly conductive, flexible, and transparent interconnections, or the active channels for nanoelectronics. However, patterning narrow graphene nanoribbons to <100 nm wide usually requires inefficient micro/nano fabrication processes, which are hard to implement for large area or flexible electronic and sensory applications. Here, we develop a precise and scalable nanowire lithography technology that enables reliable batch manufacturing of ultra-long graphene nanoribbon arrays with programmable geometry and narrow width down to ~50 nm. The orderly graphene nanoribbons are patterned out of few-layer graphene sheets by using ultra-long silicon nanowires as masks, which are produced via in-plane solid–liquid–solid guided growth and then transferred reliably onto various stiff or flexible substrates. More importantly, the geometry of the graphene nanoribbons can be predesigned and engineered into elastic two-dimensional springs to achieve outstanding stretchability of >30%, while carrying stable and repeatable electronic transport. We suggest that this convenient scalable nanowire lithography technology has great potential to establish a general and efficient strategy to batch-pattern or integrate various two-dimensional materials as active channels and interconnections for emerging flexible electronic applications.
Lanthanum chloride induces neuron damage by activating the nuclear factor-kappa B signaling pathway in activated microglia
Authors: Yan Licheng , Yang Jinghua , Yu Miao , Lu Yanxin , Huang Liling , Wang Jing , Lu Xiaobo , Jin Cuihong , Wu Shengwen , Cai Yuan 
Published: May 2019

Abstract
Lanthanum is a rare earth element which can have adverse effects on the central nervous system (CNS). However, the mechanisms of these effects are not fully understood. The activated microglia plays an important role in the pathogenesis of neurodegenerative diseases and thus could be involved in mediating the toxic effects of lanthanum on the CNS. Nuclear factor-kappa B (NF-κB) is a critical nuclear factor which regulates the expression of inflammatory mediators in the activated microglia. This study investigated the effects of lanthanum chloride (LaCl3) on the NF-κB signaling pathway and explored the relationship between the microglia activation and neuron damage induced by La in vitro. The results showed that BV2 microglial cells treated with 0, 0.05, 0.1 or 0.2 mM LaCl3 could up-regulate the expression of Iba1 protein, a marker of microglia activation, and of p-IKKαβ and p-IκBα in a dose-dependent manner. La could also increase the translocation of the NF-κB p65 subunit from the cytosol into the nucleus, and then elevate the production of NO, TNF-α, IL-1β, IL-6 and MCP-1 by BV2 microglial cells. In a neuron–microglia co-culture system, BV2 microglia treated with LaCl3 resulted in a significant increase of the rates of neuron apoptosis. Conversely, the pre-treatment with PDTC (an inhibitor of the NF-κB signaling pathway) could inhibit the release of inflammatory cytokines and reduce the number of apoptotic neurons caused by La. These findings suggested that the neuron injury induced by LaCl3 might be related to the abnormal activation of microglia, which could remarkably increase the expression and release of pro-inflammatory cytokines via activating the NF-κB signaling pathway.
ULX contribution to stellar feedback: an intermediate-mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4
Authors: Oskinova L. M. , Bik A. , Mas-Hesse J. M. , Hayes M. , Adamo A. , Östlin G. , Fürst F. , Otí-Floranes H. 
Published: May 2019

Context. X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last <40 Myr and contains some of the most massive super star clusters in the nearby Universe. Given its starburst age and its star-formation rate, ESO 338-4 is one of the most efficient nearby manufactures of neutron stars and black holes, hence providing an excellent laboratory for feedback studies.
Aims. We aim to use X-ray observations with the largest modern X-ray telescopes XMM-Newton and Chandra to unveil the most luminous accreting neutron stars and black holes in ESO 338-4.
Methods. We compared X-ray images and spectra with integral field spectroscopic observations in the optical to constrain the nature of strong X-ray emitters.
Results. X-ray observations uncover three ultraluminous X-ray sources (ULXs) in ESO 338-4. The brightest among them, ESO 338 X-1, has X-ray luminosity in excess of 1040 erg s−1. We speculate that ESO 338-4 X-1 is powered by accretion on an intermediate-mass (≳300 M⊙) black hole. We show that X-ray radiation from ULXs and hot superbubbles strongly contributes to He II ionization and general stellar feedback in this template starburst galaxy.
Genetic profiling in der Diagnostik des hereditären Prostatakarzinoms – wo stehen wir?
Authors: Thomas Christian , Tsaur Igor , Boehm Katharina 
Published: May 2019

ZusammenfassungProstatakrebs weist im Vergleich zu anderen Tumorentitäten ein heterogenes genetisches Profil auf. Dementsprechend sind auch Mutationen, die das Prostatakarzinomrisiko erhöhen, vielfältig. Manche genetische Varianten fallen bei der Risikoerhöhung nur milde ins Gewicht. Andere Genmutationen (BRCA1/2; HOXB13) erhöhen das Risiko jedoch teils erheblich. Insgesamt ist die Wahrscheinlichkeit für einen nicht familiär vorbelasteten Mann, ein Träger von Mutationen zu sein, welche mit einem erhöhten PCa-Risiko assoziiert sind, niedrig. Ist aber die familiäre Belastung durch in jungem Alter erkrankte Verwandte oder eine bereits bekannte Mutation in der Familie vorhanden, so steigt auch diese Wahrscheinlichkeit an. In diesen Fällen sollte die genetische Beratung und Testung in Betracht gezogen werden. Insbesondere soll hier an BRCA1/2-Mutationen und HOXB13-Mutationen gedacht werden. Für die breite Bevölkerungsmasse kann genetic profiling bislang jedoch nicht die PSA-Wert-Bestimmung, mpMRT der Prostata und/oder die Prostatabiopsie im Rahmen der Vorsorge oder des diagnostischen Algorithmus ersetzen. Lediglich können Männer bei Vorliegen der mit PCa assoziierten Mutationen einem engmaschigeren und früheren Screening unterzogen werden und ggf. früher eine definitive Therapie erhalten.
Positron emission tomography reporter gene strategy for use in the central nervous system
Authors: Haywood Tom , Beinat Corinne , Gowrishankar Gayatri , Patel Chirag B. , Alam Israt S. , Murty Surya , Gambhir Sanjiv Sam 
Published: May 2019

Significance
With any new treatment it is imperative the medical community has a way to monitor its effectiveness, tracking its location, monitoring its expression, and observing off-target effects. Gene/cell therapy is no exception. The growing number of studies creates a need to monitor them more accurately. A number of PET reporter gene systems have been reported; however, they have limitations, including regions of high endogenous gene expression in the central nervous system (CNS), low specificity, or endogenous expression of the reporter gene in microglia. One of these systems has been used in the clinical setting; however, its associated imaging agent lacks blood–brain barrier penetration. Our approach aims to overcome these limitations and facilitate monitoring of gene/cell therapy in the CNS.
The Mirascope: an explanation on a conceptual level
Authors: Krumphals Ingrid 
Published: May 2019

Abstract
The main objective of this paper is to provide an explanation on a conceptual level of how the Mirascope and the occurring image formation work. The physics behind a Mirascope—a well-known device consisting of two concave mirrors—is very complex. In literature, only either high level or very simplified and deficient explanations can be found. These explanations often lack a basic but detailed description on a conceptual level of the phenomena observable with the human eye. Therefore, this paper aims to give a physical explanation on a conceptual level to support learning processes in optics. Phenomena such as the diverse direction of the projected real image and the formation of the virtual image are clarified. As the focus lies on providing a basis to foster a conceptual understanding, there is no claim for a full and detailed explanation on the level of an exact ray analysis. In addition to a clarification of the content on a conceptual and educational level, suggestions for further investigations of the Mirascope with everyday items are given. The Mirascope is seen as an appropriate device for creating a learning environment following an inquiry-based approach in physics (teacher) education. This paper focuses on describing and explaining aspects of the Mirascope on a conceptual level.
Prediction of image noise contributions in proton computed tomography and comparison to measurements
Authors: Dickmann J , Wesp P , Rädler M , Rit S , Pankuch M , Johnson R P , Bashkirov V , Schulte R W , Parodi K , Landry G , Dedes G 
Published: May 2019

Abstract
We present a method to accurately predict image noise in proton computed tomography (pCT) using data generated from a Monte Carlo simulation and a patient or object model that may be generated from a prior x-ray CT image. This enables noise prediction for arbitrary beam fluence settings and, therefore, the application of fluence-modulated pCT (FMpCT), which can achieve prescribed noise targets and may significantly reduce the integral patient dose.
We extended an existing Monte Carlo simulation of a prototype pCT scanner to include effects of quenching in the energy detector scintillators and constructed a beam model from experimental tracking data. Simulated noise predictions were compared to experimental data both in the projection domain and in the reconstructed image. Noise prediction agreement between simulated and experimental data in terms of the root-mean-square (RMS) error was better than 7% for a homogeneous water phantom and a sensitometry phantom with tubular inserts. For an anthropomorphic head phantom, modeling the anatomy of a five-year-old child, the RMS error was better than 9% in three evaluated slices. We were able to reproduce subtle noise features near heterogeneities. To demonstrate the feasibility of Monte Carlo simulated noise maps for fluence modulation, we calculated a fluence profile that yields a homogeneous noise level in the image. Unlike for bow-tie filters in x-ray CT this does not require constant fluence at the detector and the shape of the fluence profile is fundamentally different.
Using an improved Monte Carlo simulation, we demonstrated the feasibility of using simulated data for accurate image noise prediction for pCT. We believe that the agreement with experimental data is sufficient to enable the future optimization of FMpCT fluence plans to achieve prescribed noise targets in a fluence-modulated acquisition.
Elliptical generalized Maxwell fish-eye lens using conformal mapping
Authors: Eskandari Hossein , Majedi Mohammad Saeed , Attari Amir Reza , Quevedo-Teruel Oscar 
Published: May 2019

Abstract
A circular graded index lens is conformally transformed to an elliptical shape using a closed-form transformation. The proposed transformation is then employed to compress a Maxwell fish-eye and its generalized version. Since the transformation is conformal, the electromagnetic properties of the device are perfectly preserved after the transformation with fully isotropic and dielectric-only materials. Ray-tracing and full-wave simulations are carried out for several cases to verify the functionality of the optically transformed lenses in geometrical optics and wave optics regimes.
Unoccupied surface and interface states in Pd thin films deposited on Fe/Ir(111) surface
Authors: Bouhassoune Mohammed , Fernandes Imara Lima , Blügel Stefan , Lounis Samir 
Published: May 2019

Abstract
We present a systematic first-principles study of the electronic surface states and resonances occuring in thin films of Pd of various thicknesses deposited on a single ferromagnetic monolayer (ML) of Fe on top of Ir(111) substrate. This system is of interest since one Pd layer deposited on Fe/Ir(111) hosts small magnetic skyrmions. The latter are topological magnetic objects with swirling spin-textures with possible implications in the context of spintronic devices since they have the potential to be used as magnetic bits for information technology. The stabilization, detection and manipulation of such non-collinear magnetic entities require a quantitative investigation and a fundamental understanding of their electronic structure. Here we investigate the nature of the unoccupied electronic states in Pd/Fe/Ir(111), which are essential in the large spin-mixing magnetoresistance signature captured using non spin-polarized scanning tunneling microscopy (Crum et al 2015 Nat. Commun.
6 8541, Hanneken et al 2015 Nat. Nanotechnol.
10 1039). To provide a complete analysis, we investigate bare Fe/Ir(111) and Pd
n = 2,7/Fe/Ir(111) surfaces. Our results demonstrate the emergence of surface and interface states after deposition of Pd MLs, which are strongly impacted by the large spin–orbit coupling of Ir surface.
Nonlinear optical dynamics of a 2D semiconductor quantum dot super-crystal: Emerging multistability, self-oscillations and chaos
Authors: Malyshev V A , Zapatero P Á , Malyshev A V , Malikov R F , Ryzhov I V 
Published: May 2019

Abstract
We conduct a theoretical study of the nonlinear optical dynamics of a 2D super-crystal comprising regularly spaced identical semiconductor quantum dots (SQDs), subjected to a resonant continuous wave excitation. A single SQD is considered as three-level ladder-like systems involving the ground, one-exciton and bi-exction states. We show that the super - crystal reveals a rich nonlinear dynamics, exhibiting multistability, self-oscillations and chaos. The behaviour is driven by the retarded SQD-SQD interactions and bi-exciton binding energy.
Ultrafast photocontrol of proton-mediated organic ferroelectric cocrystal
Authors: Umanodan T , Ishikawa T , Koshihara S , Horiuchi S , Okimoto Y 
Published: May 2019

Abstract
Photoirradiation effect in a ferroelectric cocrystal Hdppz-Hca is investigated in terms of time-resolved second harmonic (SH) generation measurements. By the photoexcitation with a visible pulse (530 nm) causing the intramolecular transition of Hca molecule, the SH intensity was suddenly suppressed by ≈30% on the time scale of picosecond, while the reflectivity scarcely changed. This result is discussed based on reversal of the polarized domain by the photoexcitation.