bluuebunny/crossref_metadata_2025 huggingface dataset:
High‐temperature 2D Fermi surface of SrTiO3 studied by energy‐filtered PEEM
Authors: Mathieu Claire , Gonzalez Sara , Lubin Christophe , Copie Olivier , Feyer Vitaliy , Schneider Claus M. , Barrett Nick
Published: September 2018

Functional oxides displaying phenomena such as 2D electron gas (2DEG) at oxide interfaces represent potential technological breakthroughs for post‐CMOS (Complementary Metal Oxide Semiconductor) electronics. Noninvasive techniques are required to study the surface chemistry and electronic structure underlying their often unique electrical properties. The sensitivity of photoemission electron microscopy (PEEM) to local potential, chemistry, and electronic structure makes it an invaluable tool for probing the near surface region of microscopic regions and domains of functional materials. In particular, PEEM allows single shot acquisition of the 2D Fermi surface and full angular probing of the symmetry‐induced intensity modulations. We present results demonstrating a 2DEG at the surface of SrTiO3(001) at 140 K. The 2DEG is created by soft X‐ray irradiation and can be reversibly controlled by a combination of soft X‐rays and oxygen partial pressure.
Modeling time‐varying effects of multilevel risk factors of hospitalizations in patients on dialysis
Authors: Li Yihao , Nguyen Danh V. , Chen Yanjun , Rhee Connie M. , Kalantar‐Zadeh Kamyar , Şentürk Damla
Published: September 2018

For chronic dialysis patients, a unique population requiring continuous medical care, methodologies to monitor patient outcomes, such as hospitalizations, over time, after initiation of dialysis, are of particular interest. Contributing to patient hospitalizations is a number of multilevel covariates such as demographics and comorbidities at the patient level and staffing composition at the dialysis facility level. We propose a varying coefficient model for multilevel risk factors (VCM‐MR) to study the time‐varying effects of covariates on patient hospitalization risk as a function of time on dialysis. The proposed VCM‐MR also includes subject‐specific random effects to account for within‐subject correlation and dialysis facility‐specific fixed effect varying coefficient functions to allow for the modeling of flexible time‐varying facility‐specific risk trajectories. An approximate EM algorithm and an iterative Newton‐Raphson approach are proposed to address the challenge of estimation of high‐dimensional parameters (varying coefficient functions) for thousands of dialysis facilities in the United States. The proposed modeling allows for comparisons between time‐varying effects of multilevel risk factors as well as testing of facility‐specific fixed effects. The method is applied to model hospitalization risk using the rich hierarchical data available on dialysis patients initiating dialysis between January 1, 2006 and December 31, 2008 from the United States Renal Data System, a large national database, where 331 443 hospitalizations over time are nested within patients, and 89 889 patients are nested within 2201 dialysis facilities. Patients are followed‐up until December 31, 2013, where the follow‐up time is truncated five years after the initiation of dialysis. Finite sample properties are studied through extensive simulations.
How government oversight adds time to contractor engineering work
Authors: Brainard Samantha M. , Szajnfarber Zoe
Published: September 2018

Oversight is necessary for evaluating the performance of contractors building complex systems for the U.S. government, but it can also result in additional program costs. In order to accurately measure the extent of these additional costs, stakeholders need to understand how oversight‐required activities add time to work. To that end, this paper presents the data from a qualitative research study to investigate how oversight adds time to contractor engineering work at a major U.S. aerospace company. We observed that oversight activities require many tasks to complete, which can add cascades of new activities that are performed in multiple iterations. Oversight activities cannot be accounted for in a binary way—oversight adds time to parts of all activities that the contractor performs. We describe the mechanisms through which oversight impacts work by extending the time spent on all activities. Understanding how added time occurs could help both contractors and government program managers determine ways to reduce unnecessary costs. Implications of these findings for systems engineers interested in conducting studies to measure the impact of oversight are discussed.
Charge generation and electrical degradation of cross‐linked polyethylene
Authors: Sekii Yasuo
Published: September 2018

Cross‐linked polyethylene is a chemically stable polymeric dielectric material with high dielectric strength, low dielectric constant and a small dissipation factor. Because of these excellent dielectric properties, cross‐linked polyethylene is used as an insulating material for electric power cables. Based on the results of much research working as an engineer of a cable manufacturer and in academia, this article describes the outline of charge generation under DC voltage stress and electrical degradation occurring in the material under AC voltage stress. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Wavelet entropy and its application for flicker contribution evaluation
Authors: Silsüpür Murat , Türkay Belgin Emre
Published: September 2018

As a result of the integration of various new load types and generation units into electric power systems, power quality disturbances such as sag–swell, harmonics, inter‐harmonics, and flicker have come into focus in the last decades. Among these disturbances, flicker is one of the serious power quality issues for both power system operators and users. In addition to having direct effects on human life such as the discomfort caused by visual disturbance, flicker may cause incorrect operations of electrical devices. Furthermore, finding a dominant flicker source in order to mitigate it and supply high‐quality power to users are the main tasks of network operators. The measurement of the flicker level is defined in the IEC 61000‐4‐15 standard as measured by a flicker meter; however, it deals only with voltage signals and is not sufficient to understand the contribution of the load and background power systems separately. Therefore, this paper proposes new approaches to the evaluation of flicker characteristics using simulated and real signals. The novelty of this paper is that it investigates the flicker characteristics in the light of multi‐resolution wavelet analysis and information‐theory‐based wavelet energy entropy analysis together and proposes a new index to interpret flickers' responsibility in load and flicker source detection. The proposed method uses only voltage and current signals and does not require additional calculation of any network parameter such as the system impedance. The proposed method is validated by simulations as well as site measurements, and the results show the accuracy and suitability of the proposed method. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Evolution of holographic Fermi arcs from a Mott insulator
Authors: Vanacore Garrett , Ramamurthy Srinidhi T. , Phillips Philip W.
Published: September 2018

Abstract

We study fermions in asymptotically anti-de Sitter black hole spacetimes which interact via novel chiral symmetry-preserving interactions. Computing the dual fermion two-point correlator, we show that these bulk interactions anisotropically gap Fermi surfaces of the boundary spectrum. Consequently, the interactions we devise provide holographic models for Fermi arcs seen ubiquitously in the pseudogap regime of the cuprates. Our interactions are modifications of the chiral symmetry-breaking Pauli coupling, which has previously been proposed as the holographic realization of Mott physics. The onset of Mott insulation and pseudogap physics are respectively discussed in the context of bulk chiral and boundary parity symmetry breaking, and the Mott transition is interpreted as a deconfinement transition of non-Fermi liquid excitations.
On the Limits of Officials’ Ability to Change Citizens’ Priorities: A Field Experiment in Local Politics
Authors: BUTLER DANIEL M. , HASSELL HANS J.G.
Published: September 2018

We test whether politicians’ communications shape their supporters’ policy priorities by conducting a field experiment in collaboration with several local elected officials. In the experiment, the officials sent out email messages to the constituents on their distribution lists. Half the constituents received messages where the official advocated for the priority of a given issue, while the other half received a placebo email. We surveyed the constituents one to two months before the message went out and again the week after the official sent the message. The experiment shows that politicians did not change citizens’ priorities in the desired direction. Moreover, citizens who received a message where the official indicated the issue was a priority were not more likely to act when invited to sign a petition on the issue. Elected officials’ ability to shape the priorities of the politically active citizens with whom they regularly communicate is limited and can even be self-defeating.
Irrigated farming systems: using the water footprint as an indicator of environmental, social and economic sustainability
Authors: Altobelli F. , Cimino O. , Natali F. , Orlandini S. , Gitz V. , Meybeck A. , Dalla Marta A.
Published: September 2018

In the current study, for the main crops cultivated in the Campania region (South of Italy), three indicators were proposed and analysed. The blue water footprint (WFb), which gives an indication of the impact of irrigation on the water resource; the gross margin WFb (GMWFb), describing the economic productivity of irrigation; and the job WFb (JWFb) that expresses the social value of blue water in terms of job opportunities. Results confirmed that water applied through irrigation is much higher compared with crop requirements. In terms of GMWFb, silage maize, maize and alfalfa had the highest values, while olive, potato and tomato had the lowest. Concerning JWFb, silage maize was the crop with the highest value. Even though a deeper analysis should be done in terms of added value in the entire supply chain, the results indicated a clear difference between the crops related to animal feeding (alfalfa, maize) and the other crops taken into consideration. In fact, for the former, both the GMWFb and the JWFb achieved their highest values. Results showed that for certain irrigation volumes and for certain crops, the economic and social impacts are very different and the choice of an irrigated crop rather than another has different repercussions in terms of environmental and socio-economic sustainability. The proposed indicators would allow water managers and farmers to assess and compare production systems in terms of the different benefits that their use of water can provide.
Sustainable wildlife extraction and the impacts of socio-economic change among the Kukama-Kukamilla people of the Pacaya-Samiria National Reserve, Peru
Authors: Kirkland Maire , Eisenberg Cristina , Bicerra Andy , Bodmer Richard E. , Mayor Pedro , Axmacher Jan C.
Published: September 2018

Throughout the tropics, hunting and fishing are critical livelihood activities for many Indigenous peoples. However, these practices may not be sustainable following recent socio-economic changes in Indigenous populations. To understand how human population growth and increased market integration affect hunting and fishing patterns, we conducted semi-structured interviews in five Kukama-Kukamilla communities living along the boundary of the Pacaya-Samiria National Reserve, in the Peruvian Amazon. Extrapolated annual harvest rates of fish and game species by these communities amounted to 1,740 t and 4,275 individuals (67 t), respectively. At least 23 fish and 27 game species were harvested. We found a positive correlation between village size and annual community-level harvest rates of fish and a negative relationship between market exposure and mean per-capita harvest rates of fish. Catch-per-unit-effort (CPUE) analyses indicated local depletion of fish populations around larger, more commercial communities. Catch-per-unit-effort of fish was lower in more commercial communities and fishers from the largest village travelled further into the Reserve, where CPUE was higher. We found no effect of village size or market exposure on harvest rates or CPUE of game species. However, larger, more commercial communities targeted larger, economically valuable species. This study provides evidence that human population growth and market-driven hunting and fishing pose a growing threat to wildlife and Indigenous livelihoods through increased harvest rates and selective harvesting of species vulnerable to exploitation.
High susceptibility of the laboratory-reared biting midges Culicoides nubeculosus to Haemoproteus infections, with review on Culicoides species that transmit avian haemoproteids
Authors: Bukauskaitė Dovilė , Iezhova Tatjana A. , Ilgūnas Mikas , Valkiūnas Gediminas
Published: September 2018

Haemosporidian parasites belonging to Haemoproteus cause avian diseases, however, vectors remain unidentified for the majority of described species. We used the laboratory-reared biting midges Culicoides nubeculosus to determine if the sporogonic development of three widespread Haemoproteus parasites completes in this insect. The midges were reared and fed on one common blackbird, white wagtail and thrush nightingale naturally infected with Haemoproteus minutus, Haemoproteus motacillae and Haemoproteus attenuatus, respectively. The engorged females were dissected in order to follow their sporogonic development. Microscopic examination was used to identify sporogonic stages. Bayesian phylogeny based on partial cytochrome b gene was constructed in order to determine phylogenetic relationships among Culicoides species-transmitted haemoproteids. All three parasites completed sporogony. Phylogenetic analysis placed Culicoides species transmitted haemoproteids in one well-supported clade, proving that such analysis readily indicates groups of dipteran insects transmitting avian haemoproteids. Available data show that 11 species of Culicoides have been proved to support complete sporogony of 18 species of avian haemoproteids. The majority of Culicoides species can act as vectors for many Haemoproteus parasites, indicating the low specificity of these parasites to biting midges, whose are globally distributed. This calls for control of haemoproteid infections during geographical translocation of infected birds.
Ethnic minority position and migrant status as risk factors for psychotic symptoms in the general population: a meta-analysis
Authors: Leaune Edouard , Dealberto Marie-Jose , Luck David , Grot Stéphanie , Zeroug-Vial Halima , Poulet Emmanuel , Brunelin Jerome
Published: September 2018

Psychotic symptoms (PS) are experienced by a substantial proportion of the general population. When not reaching a threshold of clinical relevance, these symptoms are defined as psychotic experiences (PEs) and may exist on a continuum with psychotic disorders. Unfavorable socio-environmental conditions, such as ethnic minority position (EMP) and migrant status (MS), may increase the risk of developing PS and PEs. We conducted an electronic systematic review and a meta-analysis assessing the role of EMP and MS for the development and persistence of PS in the general population. Sub-group analyses were performed investigating the influence of ethnic groups, host countries, age, types of PS, and scales. Twenty-four studies met our inclusion criteria. EMP was a relevant risk factor for reporting PS [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.22–1.70) and PEs (OR 1.36, 95% CI 1.16–1.60). The greatest risk was observed in people from the Maghreb and the Middle East ethnic groups in Europe (OR 3.30, 95% CI 2.09–5.21), in Hispanic in the USA (OR 1.98, 95% CI 1.43–2.73), and in the Black populations (OR 1.85, 95% CI 1.39–2.47). We found a significant association between MS and delusional symptoms (OR 1.47, 95% CI 1.33–1.62). We found no association between EMP and persistence of PEs.

EMP was associated with increased risk of reporting PS and PEs, and the risk was higher in ethnic groups facing deprivation and discrimination. We found an association between MS and delusional symptoms. These results raise questions about the precise role of socio-environmental factors along the psychosis continuum.
Can brief alcohol interventions in general hospital inpatients improve mental and general health over 2 years? Results from a randomized controlled trial
Authors: Freyer-Adam Jennis , Baumann Sophie , Haberecht Katja , Bischof Gallus , Meyer Christian , Rumpf Hans-Jürgen , John Ulrich , Gaertner Beate
Published: September 2018

Background

Little is known about the impact of brief alcohol interventions on mental and general health. The aim was to investigate whether brief interventions for general hospital inpatients with at-risk drinking can improve mental and general health over 2 years; and whether effects are dependent on how they are delivered: in-person or through computer-generated feedback letters (CO).

Methods

Three-arm randomized controlled trial with 6-, 12-, 18-, and 24-month follow-ups. Data were collected on 13 general hospital wards from four medical departments (internal medicine, surgical medicine, trauma surgery, and ear-nose-throat) of one university hospital in northeastern rural Germany. A consecutive sample of 961 18- to 64-year-old general hospital inpatients with at-risk alcohol use was recruited through systematic screening. Inpatients with particularly severe alcohol problems were excluded. Participants were allocated to: in-person counseling (PE), CO, and assessment only (AO). PE and CO included three contacts: on the ward, 1, and 3 months later. Mental and general health were assessed using the five-item mental health inventory (0–100) and a one-item general health measure (0, poor – 4, excellent).

Results

Latent growth models including all participants revealed: after 24 months and in contrast to AO, mental and general health were improved in PE (change in mean difference, ΔMmental = 5.13, p = 0.002, Cohen's d = 0.51; ΔMgeneral = 0.20, p = 0.005, d = 0.71) and CO (ΔMmental = 6.98, p < 0.001, d = 0.69; ΔMgeneral = 0.24, p = 0.001, d = 0.86). PE and CO did not differ significantly.

Conclusions

Beyond drinking reduction, PE and CO can improve general hospital inpatients’ self-reported mental and general health over 2 years.
THE AVANT GARDE AS EXFORM
Authors: Redhead Lauren
Published: September 2018

Peter Bürger's critique of the historical avant garde (in Theory of the Avant Garde) accounts for its ineffectual nature as a political movement because of its relationship with institutions. He argues for hermeneutics to be employed as a critique of ideology, and as a facet of the understanding of the ‘historicity of aesthetic categories’. The influence of institutions on music since 1968 has served as a central part of its critique: the work concept itself seems to enshrine political ineffectiveness and the bourgeois nature of art practice that ought to be critiqued by an avant garde. In contrast, Nicolas Bourriaud's concept of the ‘exform’ re-conceives the avant garde as outside of institutions and an idea of ‘progress’ that is aligned with a dominant capitalist ideology. He frames the task of the avant-garde artist as giving energy to ‘waste’, outside of political and ideological institutions. This type of avant-garde practice functions to ‘bring precarity to mind: to keep the notion alive that intervention in the world is possible’. This article explores the exform with respect to the work of the British composer Chris Newman and the Swiss composer Annette Schmucki, and considers how Bourriaud's approach to re-thinking the avant garde might apply specifically to contemporary and experimental music in the present.
INFERENCE AFTER MODEL AVERAGING IN LINEAR REGRESSION MODELS
Authors: Zhang Xinyu , Liu Chu-An
Published: September 2018

This article considers the problem of inference for nested least squares averaging estimators. We study the asymptotic behavior of the Mallows model averaging estimator (MMA; Hansen, 2007) and the jackknife model averaging estimator (JMA; Hansen and Racine, 2012) under the standard asymptotics with fixed parameters setup. We find that both MMA and JMA estimators asymptotically assign zero weight to the under-fitted models, and MMA and JMA weights of just-fitted and over-fitted models are asymptotically random. Building on the asymptotic behavior of model weights, we derive the asymptotic distributions of MMA and JMA estimators and propose a simulation-based confidence interval for the least squares averaging estimator. Monte Carlo simulations show that the coverage probabilities of proposed confidence intervals achieve the nominal level.
Modeling the chemistry in the icy mantles of interstellar grains
Authors: Kalvāns Juris
Published: September 2018

The diffusion and photoprocessing of molecules within interstellar ices has been verified experimentally but often not fully included in astrochemical models. With models that consider photodissociation, binary reactions, and diffusion for molecules on the surface and in bulk ice, we explored the chemistry of interstellar and circumstellar ices in gravitationally contracting low-mass starless and prestellar cores, and a protostellar envelope.

Results. Photoprocessing gradually converts mixed H2O and CO ices into CO2 and allows for a late synthesis of icy organic species. Different layers within a single icy mantle favor the synthesis different species. Deuterium-rich molecules are concentrated on the outer surface of ice. Formation of organic molecules in bulk ice lowers their average deuterium content. The abundances of major icy species can be changed by about 25-50 % because of ice photoprocessing. Inter-layer diffusion of icy species allows sequential evaporation in protostellar envelopes, which occurs over a prolonged period.
High-Temperature Chemistry in External Galaxies
Authors: Harada Nanase
Published: September 2018

In external galaxies, some galaxies have higher activities of star formation and central supermassive black holes. The interstellar medium in those galaxies can be heated by different mechanisms such as UV-heating, X-ray heating, cosmic-ray heating, and shock/mechanical heating. Chemical compositions can also be affected by those heating mechanisms. Observations of many molecular species in those nearby galaxies are now possible with the high sensitivity of Atacama Large Millimeter/sub-millimeter Array (ALMA). Here I cover different chemical models for those heating mechanisms. In addition, I present recent ALMA results of extragalactic astrochemistry including our results of a face-on galaxy M83 and an infrared-luminous merger NGC 3256.
Imaging the water snowline in protostellar envelopes
Authors: van ’t Hoff Merel L. R.
Published: September 2018

Determining the locations of the major snowlines in protostellar environments is crucial to fully understand the planet formation process and its outcome. Despite being located far enough from the central star to be spatially resolved with ALMA, the CO snowline remains difficult to detect directly in protoplanetary disks. Instead, its location can be derived from N2H+emission, when chemical effects like photodissociation of CO and N2are taken into account. The water snowline is even harder to observe than that for CO, because in disks it is located only a few AU from the protostar, and from the ground only the less abundant isotopologue H218O can be observed. Therefore, using an indirect chemical tracer, as done for CO, may be the best way to locate the water snowline. A good candidate tracer is HCO+, which is expected to be particularly abundant when its main destructor, H2O, is frozen out. Comparison of H218O and H13CO+emission toward the envelope of the Class 0 protostar IRAS2A shows that the emission from both molecules is spatially anticorrelated, providing a proof of concept that H13CO+can indeed be used to trace the water snowline in systems where it cannot be imaged directly.
Unveiling the mid-plane temperature and mass distribution in the giant-planet formation zone
Authors: Zhang Ke , Bergin Edwin A. , Blake Geoffrey A. , Cleeves L. Ilsedore , Schwarz Kamber R.
Published: September 2018

Core-accretion theory predicts that the formation of giant planets predominantly occurs at the dense mid-plane of the inner ∼50 AU of protoplanetary disks. However, due to observational limitation, this critical region remains to be the least charted area in protoplanetary disks. With its great sensitivity, ALMA recently started to image optically thin line emissions arisen from the mid-plane of the inner 50AU in nearby disks, which unlocks an exciting new path to directly constrain the physical properties of the giant planet formation zone through gas tracers. Here we present the first spatially resolved observations of the 13C18O J=3-2 line emission in the TW Hya disk. We show that this emission is optically thin even inside the CO mid-plane snowline. Combining it with the C18O J=3-2 images and the previously detected HD J=1-0 flux, we directly constrain the mid-plane temperature and optical depths of the CO gas and dust. We report a mid-plane CO snowline at 20.5 ± 1.3 AU, a mid-plane temperature distribution of 27+4−3×(R/20.5AU)-0.47+0.06−0.07 K, and a gas mass distribution of 13+8−5×(R/20.5AU)-0.9+0.4−0.3 g cm−2 between 5-20.5 AU in the TW Hya protoplanetary disk. We find a total gas/mm-sized dust mass ratio of 140 ± 40 in this region, suggesting that ∼2.4 earth mass of dust aggregates have grown to > cm sizes (and perhaps much larger).
Detection of submillimeter-wave [C I]emission in gaseous debris disks of 49 Ceti and β Pictoris
Authors: Higuchi Aya E. , Sato Aki , Tsukagoshi Takashi , Sakai Nami , Iwasaki Kazunari , Momose Munetake , Kobayashi Hiroshi , Ishihara Daisuke , Kaneda Hidehiro , Yamamoto Satoshi
Published: September 2018

We have detected [C I] 3P1–3P0 emissions in the gaseous debris disks of 49 Ceti and β Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C I] are found to resemble those of CO(J=3–2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks, and is likely formed by the photodissociation of CO. Assuming an optically thin [C I] emission with the excitation temperature ranging from 30 to 100 K, the column density of C is evaluated to be (2.2 ± 0.2) × 1017 and (2.5 ± 0.7) × 1016 cm−2 for 49 Ceti and β Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 ± 19 and 69 ± 42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H2 molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H2 molecules in the gas disk; i.e., there is an appreciable contribution of secondary gas from dust grains.
Kinetic Monte Carlo simulations of the grain-surface back-diffusion effect
Authors: Willis Eric R. , Garrod Robin T.
Published: September 2018

Back-diffusion is the phenomenon by which random walkers revisit binding sites on a lattice. This phenomenon must occur on interstellar dust particles, slowing down dust-grain reactions, but it is not accounted for by standard rate-equation models. Microscopic kinetic Monte Carlo models have been used to investigate the effect of back-diffusion on reaction rates on interstellar dust grains. Grain morphology, size, and grain-surface coverage were varied and the effects of these variations on the magnitude of the back-diffusion effect were studied for the simple H+H reaction system. This back-diffusion effect is seen to reduce reaction rates by a maximum factor of ∼5 for the canonical grain of 106 binding sites. The resulting data were fit to logarithmic functions that can be used to reproduce the effects of back-diffusion in rate-equation models.
Multiline observations of S255IR with ALMA
Authors: Zinchenko Igor , Liu Sheng-Yuan , Su Yu-Nung , Zemlyanukha Petr
Published: September 2018

We present preliminary results of the high resolution (0.10″ × 0.15″) observations of the high mass star forming region S255IR with ALMA in several spectral windows from ∼335 GHz to ∼350 GHz. The main target lines were C34S(7–6), CH3CN(19K − 18K), CO(3–2) and SiO(8–7), however many other lines of various molecules have been detected, too. We present sample spectra and maps, discuss briefly the source structure and kinematics. A new, never predicted methanol maser line has been discovered.
Chemical highlights from the Rosetta mission
Authors: Altwegg Kathrin ,   the ROSINA Team
Published: September 2018

The overall goal of the ESARosettamission was to help decipher the origin and evolution of our solar system. Looking at the chemical composition of comet 67P/Churyumov-Gerasimenko is one way of doing this. The amount of very volatile species found and the insight into their isotopic abundances show that at least some presolar ice has survived the formation of the solar system. It shows that the solar nebula was not homogenized in the region where comets formed. The D/H ratio in water furthermore indicates that Jupiter family comets and Oort cloud comets probably formed in the same regions and their difference is then purely due to their different dynamical history. The organics found in 67P are very diverse, with abundant CH- and CHO- bearing species. Sulphur bearing species like S3and S4and others show evidence of dust grain chemistry in molecular clouds.
Solid-state production of complex organic molecules: H-atom addition versus UV irradiation
Authors: Chuang K.-J.
Published: September 2018

Complex organic molecules (COMs) have been observed in comets, hot cores and cold dense regions of the interstellar medium. It is generally accepted that these COMs form on icy dust grain through the recombination reaction of radicals triggered by either energetic UV-photon or non-energetic H-atom addition processing. In this work, we present for the first time laboratory studies that allow for quantitative comparison of hydrogenation and UV-induced reactions as well as their cumulative effect in astronomically relevant CO:CH3OH=4:1 ice analogues. The formation of glycolaldehyde (GA) and ethylene glycol (EG) is confirmed in pure hydrogenation experiments at 14 K, except methyl formate (MF), which is only clearly observed in photolysis. The fractions for MF:GA:EG are 0 : (0.2-0.4) : (0.8-0.6) for pure hydrogenation, and 0.2 : 0.3 : 0.5 for UV involving experiments and can offer a diagnostic tool to derive the chemical origin of these species. The GA/EG ratios in the laboratory (0.3-1.5) compare well with observations toward different objects.
Chemical evolution in planet-forming regions. Impact on volatile abundances and C/O ratios of planet-building material
Authors: Eistrup Christian , Walsh Catherine , van Dishoeck Ewine F.
Published: September 2018

Connecting the observed composition of exoplanets to their formation sites often involves comparing the atmospheric C/O ratio to a disk midplane model with a fixed chemical composition. In this scenario chemistry during the planet formation era is not considered. However, kinetic chemical evolution during the lifetime of the gaseous disk can change the relative abundances of volatile species, thus altering the C/O ratios of planetary building blocks. In our chemical evolition models we utilize a large network of gas-phase, grain-surface and gas-grain interaction reactions, thus providing a comprehensive treatment of chemistry. The results show that, if sufficient ionisation is present, then chemistry does alter the C/O ratios of gas and ice during the epoch of planet(esimal) formation. This modifies the picture of C/O ratios in disk midplanes defined simply by volatile ice lines in a midplane of fixed chemical composition. Chemical evolution thus needs to be addressed when predicting the makeup of planets and their atmospheres.
Water Abundance of Dunes in Gale Crater, Mars From Active Neutron Experiments and Implications for Amorphous Phases
Authors: Gabriel T. S. J. , Hardgrove C. , Czarnecki S. , Rampe E. B. , Rapin W. , Achilles C. N. , Sullivan D. , Nowicki S. , Thompson L. , Litvak M. , Mitrofanov I. , Downs R. T.
Published: September 2018

We report the water abundance of Bagnold Dune sand in Gale crater, Mars by analyzing active neutron experiments using the Dynamic Albedo of Neutrons instrument. We report a bulk water‐equivalent‐hydrogen abundance of 0.68 ± 0.15 wt%, which is similar to measurements several kilometers away and from those taken of the dune surface. Thus, the dune is likely dehydrated throughout. Furthermore, we use geochemical constraints, including bulk water content, to develop compositional models of the amorphous fraction for which little information is known. We find the amorphous fraction contains ∼26‐ to 64‐wt% basaltic glass and up to ∼24‐wt% rhyolitic glass, suggesting at least one volcanic source for the dune material. We also find a range of hydrated phases may be present in appreciable abundances, either from the incorporation of eroded aqueously altered sediments or the direct alteration of the dune sand.
Influence of a Salt Plume Parameterization in a Coupled Climate Model
Authors: Sidorenko D. , Koldunov N. V. , Wang Q. , Danilov S. , Goessling H. F. , Gurses O. , Scholz P. , Sein D. V. , Volodin E. , Wekerle C. , Jung T.
Published: September 2018

Sea ice formation is accompanied by the rejection of salt which in nature tends to be mixed vertically by the formation of convective plumes. Here we analyze the influence of a salt plume parameterization in an atmosphere‐sea ice‐ocean model. Two 330‐yearlong simulations have been conducted with the AWI Climate Model. In the reference simulation, the rejected salt in the Arctic Ocean is added to the uppermost ocean layer. This approach is commonly used in climate modeling. In another experiment, employing salt plume parameterization, the rejected salt is vertically redistributed within the mixed layer based on a power law profile that mimics the penetration of salt plumes. We discuss the effects of this redistribution on the simulated mean state and on atmosphere–ocean linkages associated with the intensity of deepwater formation. We find that the salt plume parameterization leads to simultaneous increase of sea ice (volume and concentration) and decrease of sea surface salinity in the Arctic. The salt plume parameterization considerably alters the interplay between the atmosphere and the ocean in the Nordic Seas. The parameterization modifies the ocean ventilation; however, resulting changes in temperature and salinity largely compensate each other in terms of density so that the overturning circulation is not significantly affected.
Gamma oscillations as a biomarker for major depression: an emerging topic
Authors: Fitzgerald Paul J. , Watson Brendon O.
Published: September 2018

Identifying biomarkers for major depression is of high importance for improving diagnosis and treatment of this common and debilitating neuropsychiatric disorder, as the field seeks to move toward both personalized and more effective treatments. Here we focus on electroencephalography (EEG) or direct scalp voltage recordings as such a biomarker, with an emphasis on gamma and high gamma oscillations (or “rhythms”). In the last several decades, alpha and theta band rhythms have been found to provide information on depressive state as well as recovery, but the gamma band is less well characterized with respect to depression. We summarize some key findings on gamma rhythms (especially their amplitude) as a biomarker or endophenotype for major depression. These studies suggest: (1) under certain conditions gamma rhythms can distinguish subjects with major depression from healthy controls, (2) gamma may distinguish bipolar disorder from unipolar depression, (3) various pharmacological and non-pharmacological treatments that counteract depression also alter gamma, (4) animal models of depression-like behavior show gamma abnormalities, with changes in gamma associated with therapeutic recovery. The most informative approaches in the future may combine profiles of gamma band power across the brain to assess ratios of activity across regions. Overall we have good evidence to suggest that gamma rhythms may provide objective information on major depressive disease status, but we will need further work to better define the precise measures to follow.
The biological basis and clinical symptoms of CAR-T therapy-associated toxicites
Authors: Titov Aleksei , Petukhov Alexey , Staliarova Alena , Motorin Dmitriy , Bulatov Emil , Shuvalov Oleg , Soond Surinder M. , Piacentini Mauro , Melino Gerry , Zaritskey Andrey , Barlev Nickolai A.
Published: September 2018

Currently, immunotherapy is attracting a lot of attention and may potentially become a leading approach in the treatment of cancer. One emerging therapeutic, the chimeric-antigen receptor T-cell adoptive immunotherapy (CAR-T) is showing remarkable efficacy in the treatment of several B-cell malignancies. The popularity of CAR-T has been founded on two CAR T-cell products recently approved by FDA (during 2017) in the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia and B-cell lymphoma. However, their toxicities observed in clinical trials were extremely significant and in some cases even fatal with no approved algorithms for toxicity prediction being available to date. A deeper understanding of the biological basis of such complications is the key to prompt and comprehensive clinical management. Here we review the wide spectrum of effects associated with CAR T cell therapy with a major focus on the pathogenesis of cytokine release syndrome and neurotoxicity as the most common, potentially life-threatening effects of this treatment. We discuss the basis of clinical management and the existing models that predict the severity of toxicity, as well as the key factors that modulate this event. Finally, we will summarize the literature detailing universal allogenic CAR T-cells and their toxicity profile.
The genomic landscape of cutaneous SCC reveals drivers and a novel azathioprine associated mutational signature
Authors: Inman Gareth J. , Wang Jun , Nagano Ai , Alexandrov Ludmil B. , Purdie Karin J. , Taylor Richard G. , Sherwood Victoria , Thomson Jason , Hogan Sarah , Spender Lindsay C. , South Andrew P. , Stratton Michael , Chelala Claude , Harwood Catherine A. , Proby Charlotte M. , Leigh Irene M.
Published: September 2018

Cutaneous squamous cell carcinoma (cSCC) has a high tumour mutational burden (50 mutations per megabase DNA pair). Here, we combine whole-exome analyses from 40 primary cSCC tumours, comprising 20 well-differentiated and 20 moderately/poorly differentiated tumours, with accompanying clinical data from a longitudinal study of immunosuppressed and immunocompetent patients and integrate this analysis with independent gene expression studies. We identify commonly mutated genes, copy number changes and altered pathways and processes. Comparisons with tumour differentiation status suggest events which may drive disease progression. Mutational signature analysis reveals the presence of a novel signature (signature 32), whose incidence correlates with chronic exposure to the immunosuppressive drug azathioprine. Characterisation of a panel of 15 cSCC tumour-derived cell lines reveals that they accurately reflect the mutational signatures and genomic alterations of primary tumours and provide a valuable resource for the validation of tumour drivers and therapeutic targets.
Microbial metabolite sensor GPR43 controls severity of experimental GVHD
Authors: Fujiwara Hideaki , Docampo Melissa D. , Riwes Mary , Peltier Daniel , Toubai Tomomi , Henig Israel , Wu S. Julia , Kim Stephanie , Taylor Austin , Brabbs Stuart , Liu Chen , Zajac Cynthia , Oravecz-Wilson Katherine , Sun Yaping , Núñez Gabriel , Levine John E. , van den Brink Marcel R.M. , Ferrara James L. M. , Reddy Pavan
Published: September 2018

Microbiome-derived metabolites influence intestinal homeostasis and regulate graft-versus-host disease (GVHD), but the molecular mechanisms remain unknown. Here we show the metabolite sensor G-protein-coupled receptor 43 (GPR43) is important for attenuation of gastrointestinal GVHD in multiple clinically relevant murine models. GPR43 is critical for the protective effects of short-chain fatty acids (SCFAs), butyrate and propionate. Increased severity of GVHD in the absence of GPR43 is not due to baseline differences in the endogenous microbiota of the hosts. We confirm the ability of microbiome-derived metabolites to reduce GVHD by several methods, including co-housing, antibiotic treatment, and administration of exogenous SCFAs. The GVHD protective effect of SCFAs requires GPR43-mediated ERK phosphorylation and activation of the NLRP3 inflammasome in non-hematopoietic target tissues of the host. These data provide insight into mechanisms of microbial metabolite-mediated protection of target tissues from the damage caused allogeneic T cells.
PoreDesigner for tuning solute selectivity in a robust and highly permeable outer membrane pore
Authors: Chowdhury Ratul , Ren Tingwei , Shankla Manish , Decker Karl , Grisewood Matthew , Prabhakar Jeevan , Baker Carol , Golbeck John H. , Aksimentiev Aleksei , Kumar Manish , Maranas Costas D.
Published: September 2018

Monodispersed angstrom-size pores embedded in a suitable matrix are promising for highly selective membrane-based separations. They can provide substantial energy savings in water treatment and small molecule bioseparations. Such pores present as membrane proteins (chiefly aquaporin-based) are commonplace in biological membranes but difficult to implement in synthetic industrial membranes and have modest selectivity without tunable selectivity. Here we present PoreDesigner, a design workflow to redesign the robust beta-barrel Outer Membrane Protein F as a scaffold to access three specific pore designs that exclude solutes larger than sucrose (>360 Da), glucose (>180 Da), and salt (>58 Da) respectively. PoreDesigner also enables us to design any specified pore size (spanning 3–10 Å), engineer its pore profile, and chemistry. These redesigned pores may be ideal for conducting sub-nm aqueous separations with permeabilities exceeding those of classical biological water channels, aquaporins, by more than an order of magnitude at over 10 billion water molecules per channel per second.
Different patterns of clonal evolution among different sarcoma subtypes followed for up to 25 years
Authors: Hofvander Jakob , Viklund Björn , Isaksson Anders , Brosjö Otte , Vult von Steyern Fredrik , Rissler Pehr , Mandahl Nils , Mertens Fredrik
Published: September 2018

To compare clonal evolution in tumors arising through different mechanisms, we selected three types of sarcoma—amplicon-driven well-differentiated liposarcoma (WDLS), gene fusion-driven myxoid liposarcoma (MLS), and sarcomas with complex genomes (CXS)—and assessed the dynamics of chromosome and nucleotide level mutations by cytogenetics, SNP array analysis and whole-exome sequencing. Here we show that the extensive single-cell variation in WDLS has minor impact on clonal key amplicons in chromosome 12. In addition, only a few of the single nucleotide variants in WDLS were present in more than one lesion, suggesting that such mutations are of little significance in tumor development. MLS displays few mutations other than the FUS-DDIT3 fusion, and the primary tumor is genetically sometimes much more complex than its relapses, whereas CXS in general shows a gradual increase of both nucleotide- and chromosome–level mutations, similar to what has been described in carcinomas.
Molecular basis for disassembly of an importin:ribosomal protein complex by the escortin Tsr2
Authors: Schütz Sabina , Michel Erich , Damberger Fred F. , Oplová Michaela , Peña Cohue , Leitner Alexander , Aebersold Ruedi , Allain Frederic H.-T. , Panse Vikram Govind
Published: September 2018

Disordered extensions at the termini and short internal insertions distinguish eukaryotic ribosomal proteins (r-proteins) from their anucleated archaeal counterparts. Here, we report an NMR structure of such a eukaryotic-specific segment (ESS) in the r-protein eS26 in complex with the escortin Tsr2. The structure reveals how ESS attracts Tsr2 specifically to importin:eS26 complexes entering the nucleus in order to trigger non-canonical RanGTP-independent disassembly. Tsr2 then sequesters the released eS26 and prevents rebinding to the importin, providing an alternative allosteric mechanism to terminate the process of nuclear import. Notably, a Diamond–Blackfan anemia-associated Tsr2 mutant protein is impaired in binding to ESS, unveiling a critical role for this interaction in human hematopoiesis. We propose that eS26-ESS and Tsr2 are components of a nuclear sorting system that co-evolved with the emergence of the nucleocytoplasmic barrier and transport carriers.
PD-1 has a unique capacity to inhibit allergen-specific human CD4+ T cell responses
Authors: Rosskopf Sandra , Jahn-Schmid Beatrice , Schmetterer Klaus Georg , Zlabinger Gerhard J. , Steinberger Peter
Published: September 2018

T lymphocytes have a crucial role in initiating and promoting type I allergies. Their responses are tightly regulated by numerous activating and inhibitory signals provided by APCs. Here we have addressed the role of the major coinhibitory receptors PD-1, CTLA-4, BTLA and LAG-3 in allergen-specific CD4+T cell responses. PBMCs of healthy individuals and 41 patients allergic to house dust mites, birch, grass or mugwort pollen were stimulated with allergenic extracts and expression of coinhibitory receptors on responding CD4+T cells was assessed. Blocking antibodies to PD-1, CTLA-4, BTLA and LAG-3 were used to evaluate the role of coinhibitory pathways. Allergen-specific CD4+T cells showed strong upregulation of PD-1, LAG-3 and CTLA-4 upon stimulation, whereas BTLA was downregulated. Blockade of PD-1 strongly enhanced proliferation and cytokine production (IL-10; TH1 cytokines IFN-γ, TNF-α; TH2 cytokines IL-5, IL-13) of allergen-specific CD4+T cells derived from allergic as well as non-allergic individuals. BTLA blockade enhanced proliferation but not cytokine production in response to house dust mite extract. Blocking LAG-3 was ineffective and surprisingly, we observed reduced proliferation and cytokine production in presence of a CTLA-4 antibody. Our results point to a unique potency of PD-1 pathways to dampen allergen-specific human T cells.
Urate transporter inhibitor lesinurad is a selective peroxisome proliferator-activated receptor gamma modulator (sPPARγM) in vitro
Authors: Heitel Pascal , Gellrich Leonie , Heering Jan , Goebel Tamara , Kahnt Astrid , Proschak Ewgenij , Schubert-Zsilavecz Manfred , Merk Daniel
Published: September 2018

Gout is the most common arthritic disease in human but was long neglected and therapeutic options are not satisfying. However, with the recent approval of the urate transporter inhibitor lesinurad, gout treatment has experienced a major innovation. Here we show that lesinurad possesses considerable modulatory potency on peroxisome proliferator-activated receptor γ (PPARγ). Since gout has a strong association with metabolic diseases such as type 2 diabetes, this side-activity appears as very valuable contributing factor to the clinical efficacy profile of lesinurad. Importantly, despite robustly activating PPARγin vitro, lesinurad lacked adipogenic activity, which seems due to differential coactivator recruitment and is characterized as selective PPARγ modulator (sPPARγM).