bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenges of AGB modelling with dust
Authors: Ventura Paolo , Dell’Agli Flavia , Di Criscienzo Marcella , García–Hernández D. A. , Stanghellini Letizia , Schneider Raffaella 
Published: May 2017

AbstractWe report on the most recent progresses on the modelling of the asymptotic giant branch (AGB) phase. We show that dust formation in the wind of AGBs is sensitive to the mass of the precursor, low–mass AGB with mass below ~ 3 M⊙ producing mainly carbonaceous dust, whereas their counterparts of higher mass produce silicates and alumina dust. We discuss the uncertainty of the results, due to the poor knowledge of physical mechanisms highly important for AGB evolution, primarily convection and mass loss. We show how the chemical composition of planetary nebulae can be used to draw information on the main features of AGB evolution.
Dust and molecules in extra-galactic planetary nebulae
Authors: García-Hernández D. A. 
Published: May 2017

AbstractExtra-galactic planetary nebulae (PNe) permit the study of dust and molecules in metallicity environments other than the Galaxy. Their known distances lower the number of free parameters in the observations vs. models comparison, providing strong constraints on the gas-phase and solid-state astrochemistry models. Observations of PNe in the Galaxy and other Local Group galaxies such as the Magellanic Clouds (MC) provide evidence that metallicity affects the production of dust as well as the formation of complex organic molecules and inorganic solid-state compounds in their circumstellar envelopes. In particular, the lower metallicity MC environments seem to be less favorable to dust production and the frequency of carbonaceous dust features and complex fullerene molecules is generally higher with decreasing metallicity. Here, I present an observational review of the dust and molecular content in extra-galactic PNe as compared to their higher metallicity Galactic counterparts. A special attention is given to the level of dust processing and the formation of complex organic molecules (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene precursors) depending on metallicity.
The Large Magellanic Cloud PN population
Authors: Reid Warren A. 
Published: May 2017

AbstractThe Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) allow us to study late stellar evolution in environments that are respectively about a half and a quarter the metallicity of the Milky Way. With a known distance and low reddening, the LMC is an excellent environment to study PNe and conduct multiple studies. Over the past twelve months we have used the UKST Hα survey to complete our search for faint PNe in the outer most LMC beyond the 64 deg2area previously covered. Follow-up spectroscopy using AAOmega on the AAT and the 2.3-m telescope at Siding Spring Observatory have yielded a further 22 new LMC PNe while confirming the 8 previously known in the outer LMC. Medium- and high-resolution spectra have been used to measure fluxes and derive densities, mass and central star temperatures. A strong correlation is found between PNe and stellar density. This is visually displayed and given an empirical value of α = 1 PN / 2.5 × 106L⊙. The current [Oiii]-based PNLF, apart from providing an excellent standard candle, contains information about the parent population. The new PNLF, which extends down nine magnitudes, permits investigation of the faint end, the overall effects of internal extinction and provides clues to explain the insensitivity of the PNLF cutoff. When compared to the ionised density and mass of LMC PNe, the PNLF reveals it’s bimodal characteristics. Two separate evolutionary paths are evident for young, evolving PNe.
Untangling the History of M31 with Planetary Nebulae
Authors: Balick Bruce 
Published: May 2017

AbstractRecent studies of planetary nebulae and deep color-magnitude diagrams in M 31 have unveiled some unusual star-formation events beyond its spiral arms into its outer regions extending to 100 kpc in projected distance. In this paper I summarize these observations. I shall also highlight some special interpretive surprises suggested by observations of PNe related to their O/H abundances, ages, and the luminosities on PNe well beyond the inner disk.
Extended halos and intracluster light using Planetary Nebulae as tracers in nearby clusters
Authors: Arnaboldi Magda 
Published: May 2017

AbstractSince the first detection of intracluster planetary nebulae in 1996, imaging and spectroscopic surveys identified such stars to trace the radial extent and the kinematics of diffuse light in clusters. This topic of research is tightly linked with the studies of galaxy formation and evolution in dense environment, as the spatial distribution and kinematics of planetary nebulae in the outermost regions of galaxies and in the cluster cores is relevant for setting constraints on cosmological simulations. In this sense, extragalactic planetary nebulae play a very important role in the near-field cosmology, in order to measure the integrated mass as function of radius and the orbital distribution of stars in structures placed in the densest regions of the nearby universe.
Non-junctional Cx32 mediates anti-apoptotic and pro-tumor effects via epidermal growth factor receptor in human cervical cancer cells
Authors: Zhao Yifan , Lai Yongchang , Ge Hui , Guo Yunquan , Feng Xue , Song Jia , Wang Qin , Fan Lixia , Peng Yuexia , Cao Minghui , Harris Andrew L , Wang Xiyan , Tao Liang 
Published: May 2017

AbstractThe role of connexin proteins (Cx), which form gap junctions (GJ), in progression and chemotherapeutic sensitivity of cervical cancer (CaCx), is unclear. Using cervix specimens (313 CaCx, 78 controls) and CaCx cell lines, we explored relationships among Cx expression, prognostic variables and mechanisms that may link them. In CaCx specimens, Cx32 was upregulated and cytoplasmically localized, and three other Cx downregulated, relative to controls. Cx32 expression correlated with advanced FIGO staging, differentiation and increased tumor size. In CaCx cell lines, Cx32 expression suppressed streptonigrin/cisplatin-induced apoptosis in the absence of functional GJ. In CaCx specimens and cell lines, expression of Cx32 upregulated epidermal growth factor receptor (EGFR) expression. Inhibition of EGFR signaling abrogated the anti-apoptotic effect of Cx32 expression. In conclusion, upregulated Cx32 in CaCx cells produces anti-apoptotic, pro-tumorigenic effects in vivo and vitro. Abnormal Cx32 expression/localization in CaCx appears to be both a mechanism and biomarker of chemotherapeutic resistance.
MK2206 enhances the cytocidal effects of bufalin in multiple myeloma by inhibiting the AKT/mTOR pathway
Authors: Xiang Ru-Fang , Wang Yan , Zhang Nan , Xu Wen-Bin , Cao Yang , Tong Jia , Li Jun-min , Wu Ying-Li , Yan Hua 
Published: May 2017

AbstractDespite the development of promising cancer therapeutic drugs, multiple myeloma (MM) remains an incurable disease. Bufalin is a bufanolide steroid compound of the traditional Chinese medicine Chan Su that was previously shown to exert growth suppression effects on myeloma cell lines. Previous studies conducted by our group demonstrated that bufalin activated the AKT/mTOR pathway in myeloma cells, which is considered an essential pathway to disease progression and is related to drug resistance in MM. In view of the significant role of AKT in MM, the allosteric AKT inhibitor MK2206 was selected in order to enhance the antitumor effects of bufalin in different MM cell lines (NCI-H929, U266, LP-1 and RPMI8226). The data indicated that MK2206 enhanced the cytotoxicity of bufalin in MM cells, via the suppression of cellular proliferation and the induction of apoptosis, as demonstrated by cleavage of apoptosis-related proteins. This effect was further noted in the presence of exogenous interleukin-6 and/or following the co-culture of MM cells with bone marrow stromal cells (BMSC). This process was associated with the inhibition of the AKT/mTOR pathway. The combination of bufalin with MK2206 reduced the secretion of IL-6 in U266 cells. The combined treatment exhibited similar anti-MM effects in bortezomib-resistant cell lines (NCI-H929R, U266R). In addition to thein vitrocell line models, the synergistic effect was noted in primary MM cells and in MM xenografts of BALB-c and NOD-SCID mice. In conclusion, the data suggested that MK2206 significantly enhanced the cytocidal effects of bufalin in MM cells, regardless of the sensitivity to bortezomib, via the inhibition of the AKT/mTOR pathway. The study provided the basis of a promising treatment approach for MM.
Tuning the effective spin-orbit coupling in molecular semiconductors
Authors: Schott Sam , McNellis Erik R. , Nielsen Christian B. , Chen Hung-Yang , Watanabe Shun , Tanaka Hisaaki , McCulloch Iain , Takimiya Kazuo , Sinova Jairo , Sirringhaus Henning 
Published: May 2017

AbstractThe control of spins and spin to charge conversion in organics requires understanding the molecular spin-orbit coupling (SOC), and a means to tune its strength. However, quantifying SOC strengths indirectly through spin relaxation effects has proven difficult due to competing relaxation mechanisms. Here we present a systematic study of the g-tensor shift in molecular semiconductors and link it directly to the SOC strength in a series of high-mobility molecular semiconductors with strong potential for future devices. The results demonstrate a rich variability of the molecular g-shifts with the effective SOC, depending on subtle aspects of molecular composition and structure. We correlate the above g-shifts to spin-lattice relaxation times over four orders of magnitude, from 200 to 0.15 μs, for isolated molecules in solution and relate our findings for isolated molecules in solution to the spin relaxation mechanisms that are likely to be relevant in solid state systems.
Targeting the deubiquitinase STAMBP inhibits NALP7 inflammasome activity
Authors: Bednash Joseph S. , Weathington Nathaniel , Londino James , Rojas Mauricio , Gulick Dexter L. , Fort Robert , Han SeungHye , McKelvey Alison C. , Chen Bill B. , Mallampalli Rama K. 
Published: May 2017

AbstractInflammasomes regulate innate immune responses by facilitating maturation of inflammatory cytokines, interleukin (IL)-1β and IL-18. NACHT, LRR and PYD domains-containing protein 7 (NALP7) is one inflammasome constituent, but little is known about its cellular handling. Here we show a mechanism for NALP7 protein stabilization and activation of the inflammasome by Toll-like receptor (TLR) agonism with bacterial lipopolysaccharide (LPS) and the synthetic acylated lipopeptide Pam3CSK4. NALP7 is constitutively ubiquitinated and recruited to the endolysosome for degradation. With TLR ligation, the deubiquitinase enzyme, STAM-binding protein (STAMBP) impedes NALP7 trafficking to lysosomes to increase NALP7 abundance. STAMBP deubiquitinates NALP7 and STAMBP knockdown abrogates LPS or Pam3CSK4-induced increases in NALP7 protein. A small-molecule inhibitor of STAMBP deubiquitinase activity, BC-1471, decreases NALP7 protein levels and suppresses IL-1β release after TLR agonism. These findings describe a unique pathway of inflammasome regulation with the identification of STAMBP as a potential therapeutic target to reduce pro-inflammatory stress.
Kondo blockade due to quantum interference in single-molecule junctions
Authors: Mitchell Andrew K. , Pedersen Kim G. L. , Hedegård Per , Paaske Jens 
Published: May 2017

AbstractMolecular electronics offers unique scientific and technological possibilities, resulting from both the nanometre scale of the devices and their reproducible chemical complexity. Two fundamental yet different effects, with no classical analogue, have been demonstrated experimentally in single-molecule junctions: quantum interference due to competing electron transport pathways, and the Kondo effect due to entanglement from strong electronic interactions. Here we unify these phenomena, showing that transport through a spin-degenerate molecule can be either enhanced or blocked by Kondo correlations, depending on molecular structure, contacting geometry and applied gate voltages. An exact framework is developed, in terms of which the quantum interference properties of interacting molecular junctions can be systematically studied and understood. We prove that an exact Kondo-mediated conductance node results from destructive interference in exchange-cotunneling. Nonstandard temperature dependences and gate-tunable conductance peaks/nodes are demonstrated for prototypical molecular junctions, illustrating the intricate interplay of quantum effects beyond the single-orbital paradigm.
PPKs mediate direct signal transfer from phytochrome photoreceptors to transcription factor PIF3
Authors: Ni Weimin , Xu Shou-Ling , González-Grandío Eduardo , Chalkley Robert J. , Huhmer Andreas F. R. , Burlingame Alma L. , Wang Zhi-Yong , Quail Peter H. 
Published: May 2017

AbstractUpon light-induced nuclear translocation, phytochrome (phy) sensory photoreceptors interact with, and induce rapid phosphorylation and consequent ubiquitin-mediated degradation of, transcription factors, called PIFs, thereby regulating target gene expression and plant development. Nevertheless, the biochemical mechanism of phy-induced PIF phosphorylation has remained ill-defined. Here we identify a family of nuclear protein kinases, designated Photoregulatory Protein Kinases (PPK1–4; formerly called MUT9-Like Kinases (MLKs)), that interact with PIF3 and phyB in a light-induced manner in vivo. Genetic analyses demonstrate that the PPKs are collectively necessary for the normal light-induced phosphorylation and degradation of PIF3. PPK1 directly phosphorylates PIF3 in vitro, with a phosphosite pattern that strongly mimics the light-induced pattern in vivo. These data establish that the PPKs are directly involved in catalysing the photoactivated-phy-induced phosphorylation of PIF3 in vivo, and thereby are critical components of a transcriptionally centred signalling hub that pleiotropically regulates plant growth and development in response to multiple signalling pathways.
Accumulation of heme biosynthetic intermediates contributes to the antibacterial action of the metalloid tellurite
Authors: Morales Eduardo H. , Pinto Camilo A. , Luraschi Roberto , Muñoz-Villagrán Claudia M. , Cornejo Fabián A. , Simpkins Scott W. , Nelson Justin , Arenas Felipe A. , Piotrowski Jeff S. , Myers Chad L. , Mori Hirotada , Vásquez Claudio C. 
Published: May 2017

AbstractThe metalloid tellurite is highly toxic to microorganisms. Several mechanisms of action have been proposed, including thiol depletion and generation of hydrogen peroxide and superoxide, but none of them can fully explain its toxicity. Here we use a combination of directed evolution and chemical and biochemical approaches to demonstrate that tellurite inhibits heme biosynthesis, leading to the accumulation of intermediates of this pathway and hydroxyl radical. Unexpectedly, the development of tellurite resistance is accompanied by increased susceptibility to hydrogen peroxide. Furthermore, we show that the heme precursor 5-aminolevulinic acid, which is used as an antimicrobial agent in photodynamic therapy, potentiates tellurite toxicity. Our results define a mechanism of tellurite toxicity and warrant further research on the potential use of the combination of tellurite and 5-aminolevulinic acid in antimicrobial therapy.
Cross-species gene modules emerge from a systems biology approach to osteoarthritis
Authors: Mueller Alan James , Canty-Laird Elizabeth G. , Clegg Peter D. , Tew Simon R. 
Published: May 2017

AbstractComplexities in degenerative disorders, such as osteoarthritis, arise from multiscale biological, environmental, and temporal perturbations. Animal models serve to provide controlled representations of the natural history of degenerative disorders, but in themselves represent an additional layer of complexity. Comparing transcriptomic networks arising from gene co-expression data across species can facilitate an understanding of the preservation of functional gene modules and establish associations with disease phenotypes. This study demonstrates the preservation of osteoarthritis-associated gene modules, described by immune system and system development processes, across human and rat studies. Class prediction analysis establishes a minimal gene signature, including the expression of the Rho GDP dissociation inhibitor ARHGDIB, which consistently defined healthy human cartilage from osteoarthritic cartilage in an independent data set. The age of human clinical samples remains a strong confounder in defining the underlying gene regulatory mechanisms in osteoarthritis; however, defining preserved gene models across species may facilitate standardization of animal models of osteoarthritis to better represent human disease and control for ageing phenomena.
Placental O-GlcNAc-transferase expression and interactions with the glucocorticoid receptor are sex specific and regulated by maternal corticosterone exposure in mice
Authors: Pantaleon Marie , Steane Sarah E. , McMahon Kathryn , Cuffe James S. M. , Moritz Karen M. 
Published: May 2017

AbstractMaternal stress programs offspring disease in a sexually dimorphic manner with males often more adversely affected. Previous studies of maternal glucocorticoid exposure suggest male vulnerability may derive from placental alterations. The hexosamine signalling pathway and O-linked glycosylation (O-GlcNAcylation) are part of an essential adaptive survival response in healthy cells. The key enzyme involved is O-linked-N-acetylglucosamine transferase (OGT), a gene recently identified as a sex-specific placental biomarker of maternal stress. Using a mouse model of maternal corticosterone (Cort) exposure, we examined components of hexosamine biosynthesis/signalling and O-GlcNAcylation in whole placentae at E14.5. Our results demonstrate sex-specific differences in OGT levels and O-GlcNAcylation during Cort exposure which impacts on key mediators of cell survival, in particular AKT as well as the stress responsive OGT/GR transrepression complex. In male placentae only, Cort exposure increased Akt O-GlcNacylation which correlated with decreased phosphorylation. Female placentae had higher basal OGT and OGT/GR complex compared with male placentae. Cort exposure did not alter these levels in female placentae but increased global O-GlcNacylation. In male placentae Cort increased OGT and OGT/GR complex with no change in global O-GlcNacylation. These findings suggest that sex-specific differences in placental OGT play a key role in the sexually dimorphic responses to stress.
Precise and diffraction-limited waveguide-to-free-space focusing gratings
Authors: Mehta Karan K. , Ram Rajeev J. 
Published: May 2017

AbstractWe present the design and characterization of waveguide grating devices that couple visible-wavelength light at λ = 674 nm from single-mode, high index-contrast dielectric waveguides to free-space beams forming micron-scale diffraction-limited spots a designed distance and angle from the grating. With a view to application in spatially-selective optical addressing, and in contrast to previous work on similar devices, deviations from the main Gaussian lobe up to 25 microns from the focus and down to the 5 × 10−6 level in relative intensity are characterized as well; we show that along one dimension the intensity of these weak sidelobes approaches the limit imposed by diffraction from the finite field extent in the grating region. Additionally, we characterize the polarization purity in the focal region, observing at the center of the focus a low impurity <3 × 10−4 in relative intensity. Our approach allows quick, intuitive design of devices with such performance, which may be applied in trapped-ion quantum information processing and generally in any systems requiring optical routing to or from objects 10 s–100 s of microns from a chip surface, but benefitting from the parallelism and density of planar-fabricated dielectric integrated optics.
Comparative genomic analysis reveals the environmental impacts on two Arcticibacter strains including sixteen Sphingobacteriaceae species
Authors: Shen Liang , Liu Yongqin , Xu Baiqing , Wang Ninglian , Zhao Huabiao , Liu Xiaobo , Liu Fei 
Published: May 2017

AbstractHow the genomic diversity of species is driven by geographical isolation and environmental factors are not well understood for cold environments. Here, the environmental stress responses of two phylogenetically close Arcticibacter strains, A. eurypsychrophilus MJ9-5 and A. svalbardensis MN12-7, isolated from a Tibetan Plateau glacier and Svalbard soil, were analyzed. The comparative genomic analysis was performed with sixteen other related Sphingobacteriaceae species. Analyses of the relationships between growth temperature and genome composition, cold and heat shock genes showed that genomic adaption characteristics were more obvious when the strains were grouped by their upper limit in growth temperature, rather than by their minimal or optimal growth temperatures for Sphingobacteriaceae species. The very divergent genetic distance of genome fractions assigned to the functions of ‘secondary metabolism’, ‘dormancy and sporulation’ and ‘metabolism of aromatic compounds’ indicated the heterogeneous evolution of genes under different environmental pressures of the Sphingobacteriaceae species. The greatest differences between strains MJ9-5 and MN12-7 occurred in the genes devoted to the CRISPRs, osmotic adaption and metabolism of monosaccharides, nitrogen and aromatic compounds. These distinctions corresponded to two different environmental pressures, salinity and nutritional level, in the glacier ice and Svalbard soil environments.
Multitrophic Effects of Belowground Parasitoid Learning
Authors: Willett Denis S. , Alborn Hans T. , Stelinski Lukasz L. 
Published: May 2017

AbstractThe ability to learn allows organisms to take advantage of dynamic and ephemeral opportunities in their environment. Here we show that learning in belowground entomopathogenic nematodes has cascading multitrophic effects on their hosts, other nematodes, and nematophagous fungal predators. In addition to quantifying these effects, we show that social behavioral plasticity in these belowground parasitoids can amplify signaling by plant defense pathways and results in an almost doubling of insect herbivore infection by entomopathogenic nematodes. Cumulatively, these effects point to the critical role of plant signaling in regulating community structure while suggesting an equally important role for behavioral plasticity in shaping community dynamics.