bluuebunny/crossref_metadata_2025_split huggingface dataset:
Valleytronics in thermoelectric materials
Authors: Xin Jiazhan , Tang Yinglu , Liu Yintu , Zhao Xinbing , Pan Hongge , Zhu Tiejun 
Published: February 2018

AbstractThe central theme of valleytronics lies in the manipulation of valley degree of freedom for certain materials to fulfill specific application needs. While thermoelectric (TE) materials rely on carriers as working medium to absorb heat and generate power, their performance is intrinsically constrained by the energy valleys to which the carriers reside. Therefore, valleytronics can be extended to the TE field to include strategies for enhancing TE performance by engineering band structures. This review focuses on the recent progress in TE materials from the perspective of valleytronics, which includes three valley parameters (valley degeneracy, valley distortion, and valley anisotropy) and their influencing factors. The underlying physical mechanisms are discussed and related strategies that enable effective tuning of valley structures for better TE performance are presented and highlighted. It is shown that valleytronics could be a powerful tool in searching for promising TE materials, understanding complex mechanisms of carrier transport, and optimizing TE performance.
Interaction of Glide Dislocations with Extended Precipitates in Mg-Nd alloys
Authors: Huang Zhihua , Allison John E. , Misra Amit 
Published: February 2018

AbstractThe unit processes of precipitate-dislocation interaction in dilute Mg-Nd alloys are elucidated through in situ indentation experiments in TEM. Results suggest that pinned dislocations can glide along the broad facets of extended β1 precipitates, a common strengthening phase in Mg- rare earth (RE) alloys. A dislocation-theory based analysis suggests that the shape, spacing and orientation (with respect to the glide plane) of β1 precipitates may favor glide of pinned dislocations along interfaces as opposed to the classical mechanism of bowing and looping around the precipitate.
Hypoglycemic and hypolipidemic effect of S-allyl-cysteine sulfoxide (alliin) in DIO mice
Authors: Zhai Baiqiang , Zhang Chuanhai , Sheng Yao , Zhao Changhui , He Xiaoyun , Xu Wentao , Huang Kunlun , Luo Yunbo 
Published: February 2018

AbstractAlliin (S-allyl cysteine sulfoxide) is a bioactive sulfoxide compound derived from garlic. To evaluate the preventive effect of alliin against metabolic risk factors in diet induced obese (DIO) mice, we treated the C57BL/6J DIO mice with drinking water with or without alliin (0.1 mg/ml) for 8 weeks. Results showed that alliin had no significant effect on the body weight, adiposity or energy balance. However, alliin treatment enhanced glucose homeostasis, increased insulin sensitivity and improved the lipid profile in the DIO mice. This was, at least partly, attributable to alliin induced modulation of the intestinal microbiota composition, typically decreasedLachnospiraceaeand increasedRuminococcaceae. From above, we conclude that alliin has nutraceutical or even medicinal potential in prevention of diabetes and lipid metabolic disorders.
mTOR-dependent alterations of Kv1.1 subunit expression in the neuronal subset-specific Pten knockout mouse model of cortical dysplasia with epilepsy
Authors: Nguyen Lena H. , Anderson Anne E. 
Published: February 2018

AbstractCortical dysplasia (CD) is a common cause for intractable epilepsy. Hyperactivation of the mechanistic target of rapamycin (mTOR) pathway has been implicated in CD; however, the mechanisms by which mTOR hyperactivation contribute to the epilepsy phenotype remain elusive. Here, we investigated whether constitutive mTOR hyperactivation in the hippocampus is associated with altered voltage-gated ion channel expression in the neuronal subset-specific Pten knockout (NS-Pten KO) mouse model of CD with epilepsy. We found that the protein levels of Kv1.1, but not Kv1.2, Kv1.4, or Kvβ2, potassium channel subunits were increased, along with altered Kv1.1 distribution, within the hippocampus of NS-Pten KO mice. The aberrant Kv1.1 protein levels were present in young adult (≥postnatal week 6) but not juvenile (≤postnatal week 4) NS-Pten KO mice. No changes in hippocampal Kv1.1 mRNA levels were found between NS-Pten KO and WT mice. Interestingly, mTOR inhibition with rapamycin treatment at early and late stages of the pathology normalized Kv1.1 protein levels in NS-Pten KO mice to WT levels. Together, these studies demonstrate altered Kv1.1 protein expression in association with mTOR hyperactivation in NS-Pten KO mice and suggest a role for mTOR signaling in the modulation of voltage-gated ion channel expression in this model.
Quantitative 3-D morphometric analysis of individual dendritic spines
Authors: Basu Subhadip , Saha Punam Kumar , Roszkowska Matylda , Magnowska Marta , Baczynska Ewa , Das Nirmal , Plewczynski Dariusz , Wlodarczyk Jakub 
Published: February 2018

AbstractThe observation and analysis of dendritic spines morphological changes poses a major challenge in neuroscience studies. The alterations of their density and/or morphology are indicators of the cellular processes involved in neural plasticity underlying learning and memory, and are symptomatic in neuropsychiatric disorders. Despite ongoing intense investigations in imaging approaches, the relationship between changes in spine morphology and synaptic function is still unknown. The existing quantitative analyses are difficult to perform and require extensive user intervention. Here, we propose a new method for (1) the three-dimensional (3-D) segmentation of dendritic spines using a multi-scale opening approach and (2) define 3-D morphological attributes of individual spines for the effective assessment of their structural plasticity. The method was validated using confocal light microscopy images of dendritic spines from dissociated hippocampal cultures and brain slices (1) to evaluate accuracy relative to manually labeled ground-truth annotations and relative to the state-of-the-art Imaris tool, (2) to analyze reproducibility of user-independence of the segmentation method, and (3) to quantitatively analyze morphological changes in individual spines before and after chemically induced long-term potentiation. The method was monitored and used to precisely describe the morphology of individual spines in real-time using consecutive images of the same dendritic fragment.
Shuang-Huang-Lian injection induces an immediate hypersensitivity reaction via C5a but not IgE
Authors: Gao Yuan , Hou Rui , Han Yixin , Fei Qiaoling , Cai Runlan , Qi Yun 
Published: February 2018

AbstractAmong traditional Chinese medicine injections, intravenous Shuang-Huang-Lian (IV-SHL) has the highest incidence of injection-induced immediate hypersensitivity reactions (IHRs). The precise mechanisms of IV-SHL-induced IHRs remain ambiguous. In this study, we investigated the mechanisms of SHL injection (SHLI)-induced IHRs. Our data showed that serum total IgE and mouse mast cell protease 1 (MMCP1) levels were higher in the SHLI antiserum; however, these effects of SHLI disappeared in the antibiotic-treated mice. SHLI caused intraplantar vasopermeability and shock during the first local or systemic injection. SHLI-induced nonallergic IHRs were attributed to its intermediate fraction F2 (the extract of Lonicerae Japonicae Flos and Fructus forsythiae), and could be blocked by antagonists for histamine or C5a, rather than PAF or C3a. Eight constituents of F2 were able to directly activate C5 to promote local vasopermeability at the mg/mL level. In conclusion, SHLI-induced IHRs are not mediated by IgE. SHLI or its F2 can directly activate blood C5. Subsequently, C5a is likely to provoke histamine release from its effector cells (e.g., mast cells and basophils), indicating that histamine is a principal effector of IHRs induced by SHLI.
Foxm1 controls a pro-stemness microRNA network in neural stem cells
Authors: Besharat Zein Mersini , Abballe Luana , Cicconardi Francesco , Bhutkar Arjun , Grassi Luigi , Le Pera Loredana , Moretti Marta , Chinappi Mauro , D’Andrea Daniel , Mastronuzzi Angela , Ianari Alessandra , Vacca Alessandra , De Smaele Enrico , Locatelli Franco , Po Agnese , Miele Evelina , Ferretti Elisabetta 
Published: February 2018

AbstractCerebellar neural stem cells (NSCs) require Hedgehog-Gli (Hh-Gli) signalling for their maintenance and Nanog expression for their self-renewal. To identify novel molecular features of this regulatory pathway, we used next-generation sequencing technology to profile mRNA and microRNA expression in cerebellar NSCs, before and after induced differentiation (Diff-NSCs). Genes with higher transcript levels in NSCs (vs. Diff-NSCs) included Foxm1, which proved to be directly regulated by Gli and Nanog. Foxm1 in turn regulated several microRNAs that were overexpressed in NSCs: miR-130b, miR-301a, and members of the miR-15~16 and miR-17~92 clusters and whose knockdown significantly impaired the neurosphere formation ability. Our results reveal a novel Hh-Gli-Nanog-driven Foxm1-microRNA network that controls the self-renewal capacity of NSCs.
Diversity and evolution of four-domain voltage-gated cation channels of eukaryotes and their ancestral functional determinants
Authors: Pozdnyakov Ilya , Matantseva Olga , Skarlato Sergei 
Published: February 2018

AbstractFour-domain voltage-gated cation channels (FVCCs) represent a large family of pseudo-tetrameric ion channels which includes voltage-gated calcium (Cav) and sodium (Nav) channels, as well as their homologues. These transmembrane proteins are involved in a wide range of physiological processes, such as membrane excitability, rhythmical activity, intracellular signalling, etc. Information about actual diversity and phylogenetic relationships of FVCCs across the eukaryotic tree of life is scarce. We for the first time performed a taxonomically broad phylogenetic analysis of 277 FVCC sequences from a variety of eukaryotes and showed that many groups of eukaryotic organisms have their own clades of FVCCs. Moreover, the number of FVCC lineages in several groups of unicellular eukaryotes is comparable to that in animals. Based on the primary structure of FVCC sequences, we characterised their functional determinants (selectivity filter, voltage sensor, Nav-like inactivation gates, Cavβ-interaction motif, and calmodulin-binding region) and mapped them on the obtained phylogeny. This allowed uncovering of lineage-specific structural gains and losses in the course of FVCC evolution and identification of ancient structural features of these channels. Our results indicate that the ancestral FVCC was voltage-sensitive, possessed a Cav-like selectivity filter, Nav-like inactivation gates, calmodulin-binding motifs and did not bear the structure for Cavβ-binding.
“Betting on nature” or “betting on others”: anti-coordination induces uniquely high levels of entropy
Authors: Chierchia Gabriele , Nagel Rosemarie , Coricelli Giorgio 
Published: February 2018

AbstractUncertainty in the form of risk or ambiguity can arise from the interaction with nature and other players, while strategic uncertainty arises only in interactions with others. Here, we systematically compare binary decisions between a safe option and a potentially higher paying but uncertain option in four experimental conditions with the same potential monetary outcomes: coordination vs. anti coordination games, as well as risky and ambiguous lotteries. In each condition, we progressively increase the value of the safe option and measure subjects’ certainty equivalents (i.e., the specific safe payoff-threshold that makes a subject indifferent between the two options). We find that anti-coordination games and ambiguous lotteries elicit equally high aversion to uncertainty, relative to the other domains. In spite of this similarity, we find that subjects alternate between the safe and uncertain options much more frequently, thus displaying higher entropy, under anti-coordination relative to any of the other environments. These differences are predicted by theories of recursive reasoning in strategic games (e.g., thinking what others think we think etc.). Indeed, this can occur when interacting with intentional counterparts, but not with nature.
The transcriptomic signature of different sexes in two protogynous hermaphrodites: Insights into the molecular network underlying sex phenotype in fish
Authors: Tsakogiannis A. , Manousaki T. , Lagnel J. , Sterioti A. , Pavlidis M. , Papandroulakis N. , Mylonas C. C. , Tsigenopoulos C. S. 
Published: February 2018

AbstractSex differentiation is a puzzling problem in fish due to the variety of reproductive systems and the flexibility of their sex determination mechanisms. The Sparidae, a teleost family, reflects this remarkable diversity of sexual mechanisms found in fish. Our aim was to capture the transcriptomic signature of different sexes in two protogynous hermaphrodite sparids, the common pandora Pagellus erythrinus and the red porgy Pagrus pagrus in order to shed light on the molecular network contributing to either the female or the male phenotype in these organisms. Through RNA sequencing, we investigated sex-specific differences in gene expression in both species’ brains and gonads. The analysis revealed common male and female specific genes/pathways between these protogynous fish. Whereas limited sex differences found in the brain indicate a sexually plastic tissue, in contrast, the great amount of sex-biased genes observed in gonads reflects the functional divergence of the transformed tissue to either its male or female character. Α common “crew” of well-known molecular players is acting to preserve either sex identity of the gonad in these fish. Lastly, this study lays the ground for a deeper understanding of the complex process of sex differentiation in two species with an evolutionary significant reproductive system.
Reconstruction of the two-dimensional gravitational potential of galaxy clusters from X-ray and Sunyaev-Zel’dovich measurements
Authors: Tchernin C. , Bartelmann M. , Huber K. , Dekel A. , Hurier G. , Majer C. L. , Meyer S. , Zinger E. , Eckert D. , Meneghetti M. , Merten J. 
Published: February 2018

Context. The mass of galaxy clusters is not a direct observable, nonetheless it is commonly used to probe cosmological models. Based on the combination of all main cluster observables, that is, the X-ray emission, the thermal Sunyaev–Zel’dovich (SZ) signal, the velocity dispersion of the cluster galaxies, and gravitational lensing, the gravitational potential of galaxy clusters can be jointly reconstructed.
Aims. We derive the two main ingredients required for this joint reconstruction: the potentials individually reconstructed from the observables and their covariance matrices, which act as a weight in the joint reconstruction. We show here the method to derive these quantities. The result of the joint reconstruction applied to a real cluster will be discussed in a forthcoming paper.
Methods. We apply the Richardson-Lucy deprojection algorithm to data on a two-dimensional (2D) grid. We first test the 2D deprojection algorithm on a β-profile. Assuming hydrostatic equilibrium, we further reconstruct the gravitational potential of a simulated galaxy cluster based on synthetic SZ and X-ray data. We then reconstruct the projected gravitational potential of the massive and dynamically active cluster Abell 2142, based on the X-ray observations collected with XMM-Newton and the SZ observations from the Planck satellite. Finally, we compute the covariance matrix of the projected reconstructed potential of the cluster Abell 2142 based on the X-ray measurements collected with XMM-Newton.
Results. The gravitational potentials of the simulated cluster recovered from synthetic X-ray and SZ data are consistent, even though the potential reconstructed from X-rays shows larger deviations from the true potential. Regarding Abell 2142, the projected gravitational cluster potentials recovered from SZ and X-ray data reproduce well the projected potential inferred from gravitational-lensing observations. We also observe that the covariance matrix of the potential for Abell 2142 reconstructed from XMM-Newton data sensitively depends on the resolution of the deprojected grid and on the smoothing scale used in the deprojection.
Conclusions. We show that the Richardson-Lucy deprojection method can be effectively applied on a grid and that the projected potential is well recovered from real and simulated data based on X-ray and SZ signal. The comparison between the reconstructed potentials from the different observables provides additional information on the validity of the assumptions as function of the projected radius.
The long-period massive binary HD 54662 revisited
Authors: Mossoux E. , Mahy L. , Rauw G. 
Published: February 2018

Context.HD 54662is an O-type binary star belonging to the CMa OB1 association. Because of its long-period orbit, this system is an interesting target to test the adiabatic wind shock model.Aims. The goal of this study is to improve our knowledge of the orbital and stellar parameters ofHD 54662and to analyze its X-ray emission to test the theoretical scaling of X-ray emission with orbital separation for adiabatic wind shocks.Methods. We applied a spectral disentangling code to a set of optical spectra to determine the radial velocities and the individual spectra of the primary and secondary stars. The orbital solution of the system was established and the reconstructed individual spectra were analyzed by means of the CMFGEN model atmosphere code. We fitted two X-ray spectra using a Markov chain Monte Carlo algorithm and compared these spectra to the emission expected from adiabatic shocks.Results. We determine an orbital period of 2103.4 days, a surprisingly low orbital eccentricity of 0.11, and a mass ratiom2/m1of 0.84. Combined with the orbital inclination inferred in a previous astrometric study, we obtain surprisingly low masses of 9.7 and 8.2M⊙. From the disentangled primary and secondary spectra, we infer O6.5 spectral types for both stars, of which the primary is about two times brighter than the secondary. The softness of the X-ray spectra for the two observations, the very small variation of best-fitting spectral parameters, and the comparison of the X-ray-to-bolometric luminosity ratio with the canonical value for O-type stars allow us to conclude that X-ray emission from the wind interaction region is quite low and that the observed emission is rather dominated by the intrinsic emission from the stars. We cannot confirm the runaway status previously attributed toHD 54662by computing the peculiar radial and tangential velocities. We find no X-ray emission associated with the bow shock detected in the infrared.Conclusions. The lack of hard X-ray emission from the wind-shock region suggests that the mass-loss rates are lower than expected and/or that the pre-shock wind velocities are much lower than the terminal wind velocities. The bow shock associated withHD 54662possibly corresponds to a wind-blown arc created by the interaction of the stellar winds with the ionized gas of the CMa OB1 association rather than by a large differential velocity between the binary and the surrounding interstellar medium.
The contribution of faint AGNs to the ionizing background at z ~ 4
Authors: Grazian A. , Giallongo E. , Boutsia K. , Cristiani S. , Vanzella E. , Scarlata C. , Santini P. , Pentericci L. , Merlin E. , Menci N. , Fontanot F. , Fontana A. , Fiore F. , Civano F. , Castellano M. , Brusa M. , Bonchi A. , Carini R. , Cusano F. , Faccini M. , Garilli B. , Marchetti A. , Rossi A. , Speziali R. 
Published: February 2018

Context. Finding the sources responsible for the hydrogen reionization is one of the most pressing issues in observational cosmology. Bright quasi-stellar objects (QSOs) are known to ionize their surrounding neighborhood, but they are too few to ensure the required HI ionizing background. A significant contribution by faint active galactic nuclei (AGNs), however, could solve the problem, as recently advocated on the basis of a relatively large space density of faint active nuclei at z > 4.
Aims. This work is part of a long-term project aimed at measuring the Lyman Continuum escape fraction for a large sample of AGNs at z ~ 4 down to an absolute magnitude of M1450 ~ −23. We have carried out an exploratory spectroscopic program to measure the HI ionizing emission of 16 faint AGNs spanning a broad U − I color interval, with I ~ 21–23, and 3.6 < z < 4.2. These AGNs are three magnitudes fainter than the typical SDSS QSOs (M1450 ≲−26) which are known to ionize their surrounding IGM at z ≳ 4.
Methods. We acquired deep spectra of these faint AGNs with spectrographs available at the VLT, LBT, and Magellan telescopes, that is, FORS2, MODS1-2, and LDSS3, respectively. The emission in the Lyman Continuum region, close to 900 Å rest frame, has been detected with a signal to noise ratio of ~10–120 for all 16 AGNs. The flux ratio between the 900 Å rest-frame region and 930 Å provides a robust estimate of the escape fraction of HI ionizing photons.
Results. We have found that the Lyman Continuum escape fraction is between 44 and 100% for all the observed faint AGNs, with a mean value of 74% at 3.6 < z < 4.2 and − 25.1 ≲ M1450 ≲−23.3, in agreement with the value found in the literature for much brighter QSOs (M1450 ≲−26) at the same redshifts. The Lyman Continuum escape fraction of our faint AGNs does not show any dependence on the absolute luminosities or on the observed U − I colors of the objects. Assuming that the Lyman Continuum escape fraction remains close to ~75% down to M1450 ~ − 18, we find that the AGN population can provide between 16 and 73% (depending on the adopted luminosity function) of the whole ionizing UV background at z ~ 4, measured through the Lyman forest. This contribution increases to 25–100% if other determinations of the ionizing UV background are adopted from the recent literature.
Conclusions. Extrapolating these results to z ~ 5–7, there are possible indications that bright QSOs and faint AGNs can provide a significant contribution to the reionization of the Universe, if their space density is high at M1450 ~ −23.
Discovery of X-ray pulsations in the Be/X-ray binary IGR J06074+2205
Authors: Reig P. , Zezas A. 
Published: February 2018

Context. IGR J06074+2205 is a poorly studied X-ray source with a Be star companion. It has been proposed to belong to the group of Be/X-ray binaries (BeXBs). In BeXBs, accretion onto the neutron star occurs via the transfer of material from the Be star’s circumstellar disk. Thus, in the absence of the disk, no X-ray should be detected.
Aims. The main goal of this work is to study the quiescent X-ray emission of IGR J06074+2205 during a disk-loss episode.
Methods. We obtained light curves at different energy bands and a spectrum covering the energy range 0.4–12 keV. We used Fourier analysis to study the aperiodic variability and epoch folding methods to study the periodic variability. Model fitting to the energy spectrum allowed us to identify the possible physical processes that generated the X-rays.
Results. We show that at the time of the XMM-Newton observation, the decretion disk around the Be star had vanished. Still, accretion appears as the source of energy that powers the high-energy radiation in IGR J06074+2205. We report the discovery of X-ray pulsations with a pulse period of 373.2 s and a pulse fraction of ~50%. The 0.4–12 keV spectrum is well described by an absorbed power law and blackbody components with the best fitting parameters: NH = (6.2 ± 0.5) × 1021 cm−2, kTbb = 1.16 ± 0.03 keV, and Γ = 1.5 ± 0.1. The absorbed X-ray luminosity is LX = 1.4 × 1034 erg s−1 assuming a distance of 4.5 kpc.
Conclusions. The detection of X-ray pulsations confirms the nature of IGR J06074+2205 as a BeXB. We discuss various scenarios to explain the quiescent X-ray emission of this pulsar. We rule out cooling of the neutron star surface and magnetospheric emission and conclude that accretion is the most likely scenario. The origin of the accreted material remains an open question.