bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mars Initial Reference Ionosphere (MIRI) Model: Updates and Validations Using MAVEN, MEX, and MRO Data Sets
Authors: Mendillo Michael , Narvaez Clara , Trovato Jeffrey , Withers Paul , Mayyasi Majd , Morgan David , Kopf Andrew , Gurnett Donald , Němec Frantisek , Campbell Bruce 
Published: June 2018

AbstractThe Mars Initial Reference Ionosphere (MIRI) model is a semiempirical formulation designed to provide climatological estimates of key parameters of the Martian ionosphere. For the new MIRI‐2018 version, an expanded database is used from the Mars Express/Mars Advanced Radar for Subsurface and Ionosphere Sounding/Active Ionospheric Sounding (MEX/MARSIS/AIS) instrument, consisting of 215,818 values of maximum electron density of the M2‐layer (NmM2) from the years 2005–2015. These data are organized by photochemical‐equilibrium equations to obtain a functional dependence of NmM2 upon solar drivers (flux and solar zenith angle). The resulting peak density is used to calibrate normalized electron density profiles [Ne (h)] derived from theory and an empirical model. The MIRI‐2018 thus provides estimates of NmM2, Ne (h), and total electron content (TEC) for any date past or future. Validation using Mars Atmosphere and Volatile EvolutioN (MAVEN)'s new radio occultation science experiment (ROSE) was successful for NmM2 values, but MIRI was found to overestimate TEC values. The validation failure for TEC was traced to overestimates of plasma at low altitudes (M1 layer). A separate module for TEC was derived using 126,055 values from the Mars Reconnaissance Orbiter/SHAllow RADar (MRO/SHARAD) TEC database from 2006 to 2014. Validation of this new TEC module with ROSE data was successful. Future improvements to MIRI‐2018 require new ways to characterize the bottomside ionosphere's contribution to the TEC integral for midday (low solar zenith angle) conditions. This requires new simulation studies of secondary ionization rates by photoelectrons produced via the primary X‐ray ionization process for the M1 layer.
Periodic Oscillations in the D Region Ionosphere After the 2011 Tohoku Earthquake Using LF Standard Radio Waves
Authors: Ohya Hiroyo , Tsuchiya Fuminori , Takishita Yuta , Shinagawa Hiroyuki , Nozaki Kenro , Shiokawa Kazuo 
Published: June 2018

AbstractWe report the first observations of ~100‐s periodic oscillations of intensity in low‐frequency (LF) standard radio waves over Japan at 05:51–05:56 UT, which was about 4 min and 42 s after mainshock onset of “the 2011 off the Pacific coast of Tohoku earthquake” on 11 March 2011 (Mw 9.0). The LF radio wave propagation paths used in this study were JJY (Japan, 60 kHz)‐Rikubetsu (RKB, Japan), and BPC (China, 68.5 kHz)‐RKB, where the minimum distances between the epicenter and the LF propagation paths were 413.6 and 561.5 km, respectively. The observed modulations in intensity and phase were about 0.1 dB and 0.5°, respectively. Based on a numerical simulation of the neutral atmosphere and the wave‐hop method, the occurrence time of the ~100‐s periodic oscillations was in good agreement with the total propagation time of the Rayleigh wave that spread concentrically from the epicenter to the LF propagation paths and acoustic waves propagating vertically from the Earth's surface to the bottom of the ionosphere. Variations in synthesized electric field intensity of ground waves and sky waves, calculated by the wave hop method up to 10 hops, reproduced similar ~100‐s periodic oscillations that were caused by the difference in arrival time of the acoustic waves excited by the Rayleigh waves at each hop point. The amplitude of the D region electron density variations at 70 km altitude during the ~100‐s periodic oscillation was estimated to be about 1% compared to the background electron density, based on the numerical simulation.
Mapping of Geologic Structures in the Niobe‐Aphrodite Map Area of Venus: Unraveling the History of Tectonic Regime Change
Authors: Hansen V. L. , López I. 
Published: June 2018

AbstractRecent construction of 1:10 M IMaps of Niobe Planitia and Aphrodite Terra paints a rich picture of Venus evolution. Using the Niobe‐Aphrodite map area (>25% of Venus) as an example, we illustrate the methodology and importance of detailed structural mapping at large regional scales in order to identify tectonic domains that lead to the discovery of global‐scale geodynamic evolution and operative processes. We highlight differences between lithodemic and lithostratigraphic units in geologic mapping. We step through a series of structural element maps that reveal the character of at least three different tectonic domains and evolving tectonic regimes that reflect changing geodynamic processes, here divided into three eras. The ancient era encompasses formation of tessera terrain and represents a time of unique global and environmental conditions marked by globally thin lithosphere. The second era resulted in formation of the Artemis superstructure. The ~13,000‐km‐diameter footprint of the Artemis superstructure is huge but not global, although associated mantle flow patterns could have had a global reach. As formation of the Artemis superstructure waned, tectonic activity became more focused leading to formation of the fracture zone complex. This complex extends beyond the map area connecting with Atla, Beta, and Themis regiones and associated fracture zones, marking the youngest era. Structural mapping of the Niobe‐Aphrodite map area indicates that Venus exhibits a complex, multistage history like other terrestrial planets, which probably extends to several billion years. Given that Venus never developed plate tectonics, Venus' preserved surface record is likely significantly richer than that of Earth.
Temporal dynamics of eukaryotic microbial diversity at a coastal Pacific site
Authors: Nagarkar Maitreyi , Countway Peter D , Du Yoo Yeong , Daniels Emy , Poulton Nicole J , Palenik Brian 
Published: June 2018

Abstract
High-throughput sequencing of ocean biomes has revealed vast eukaryotic microbial diversity, a significant proportion of which remains uncharacterized. Here we use a temporal approach to understanding eukaryotic diversity at the Scripps Pier, La Jolla, California, USA, via high-throughput amplicon sequencing of the 18S rRNA gene, the abundances of both Synechococcus and Synechococcus grazers, and traditional oceanographic parameters. We also exploit our ability to track operational taxonomic units (OTUs) temporally to evaluate the ability of 18S sequence-based OTU assignments to meaningfully reflect ecological dynamics. The eukaryotic community is highly dynamic in terms of both species richness and composition, although proportional representation of higher-order taxa remains fairly consistent over time. Synechococcus abundance fluctuates throughout the year. OTUs unique to dates of Synechococcus blooms and crashes or enriched in Synechococcus addition incubation experiments suggest that the prasinophyte Tetraselmis sp. and Gymnodinium-like dinoflagellates are likely Synechococcus grazers under certain conditions, and may play an important role in their population fluctuations.
Nutrient transport suggests an evolutionary basis for charged archaeal surface layer proteins
Authors: Li Po-Nan , Herrmann Jonathan , Tolar Bradley B , Poitevin Frédéric , Ramdasi Rasika , Bargar John R , Stahl David A , Jensen Grant J , Francis Christopher A , Wakatsuki Soichi , van den Bedem Henry 
Published: June 2018

Abstract
Surface layers (S-layers) are two-dimensional, proteinaceous, porous lattices that form the outermost cell envelope component of virtually all archaea and many bacteria. Despite exceptional sequence diversity, S-layer proteins (SLPs) share important characteristics such as their ability to form crystalline sheets punctuated with nano-scale pores, and their propensity for charged amino acids, leading to acidic or basic isoelectric points. However, the precise function of S-layers, or the role of charged SLPs and how they relate to cellular metabolism is unknown. Nano-scale lattices affect the diffusion behavior of low-concentration solutes, even if they are significantly smaller than the pore size. Here, we offer a rationale for charged S-layer proteins in the context of the structural evolution of S-layers. Using the ammonia-oxidizing archaea (AOA) as a model for S-layer geometry, and a 2D electrodiffusion reaction computational framework to simulate diffusion and consumption of the charged solute ammonium (NH4+), we find that the characteristic length scales of nanoporous S-layers elevate the concentration of NH4+ in the pseudo-periplasmic space. Our simulations suggest an evolutionary, mechanistic basis for S-layer charge and shed light on the unique ability of some AOA to oxidize ammonia in environments with nanomolar NH4+ availability, with broad implications for comparisons of ecologically distinct populations.
Linc00462 promotes pancreatic cancer invasiveness through the miR-665/TGFBR1-TGFBR2/SMAD2/3 pathway
Authors: Zhou Bin , Guo Weidong , Sun Chuandong , Zhang Bingyuan , Zheng Fang 
Published: June 2018

AbstractEmerging evidence has identified that long non-coding RNAs (lncRNAs) may play an important role in the pathogenesis of many cancers, pancreatic cancer (PC) included. However, the role of linc00462 in PC remains unclear. The aim of our present study was to investigate the potential functions of linc00462 in PC and to identify the underlying mechanisms of action. CCK8 assay, transwell assay, cell cycle assay, cell apoptosis assay, EdU assay, western blot assay, cell adhesion assay, HE staining, IF staining, ELISA assay, vivo growth and metastasis assay, and colony formation assay were performed. We demonstrated that OSM mediated up-regulation of linc00462 promoted cell proliferation by accelerating cell cycle process and inhibiting cell apoptosis and adhesion in vitro, enhanced cell migration and invasion by accelerating EMT process, promoted tumor growth and matastasis in vivo and was associated with large tumor size, poor tumor differentiation, TNM stage and distant metastasis in patients of PC. In addition, we demonstrated that linc00462 was a target of miR-665. Linc00462 overexpression enhanced the expression levels of TGFBR1 and TGFBR2, and thus activated the SMAD2/3 pathway in PC cells. In conclusion, linc00462/miR-665/TGFBR1/2 regulatory network may shed light on tumorigenesis in PC.
Proscillaridin A induces apoptosis and suppresses non-small-cell lung cancer tumor growth via calcium-induced DR4 upregulation
Authors: Li Run-Ze , Fan Xing-Xing , Duan Fu-Gang , Jiang Ze-Bo , Pan Hu-Dan , Luo Lian-Xiang , Zhou Yan-Ling , Li Ying , Yao Ying-Jia , Yao Xiao-Jun , Leung Elaine Lai-Han , Liu Liang 
Published: June 2018

AbstractNon-small-cell lung cancer (NSCLC) is the predominant histological type of lung cancer and is characterized by the highest mortality and incidence rates among these types of malignancies. Cardiac glycosides, a class of natural products, have been identified as a potential type of chemotherapeutic agent. This study aims to investigate the anti-cancer effects and the mechanisms of action of Proscillaridin A (P.A) in NSCLC cells. In vitro sodium–potassium pump (Na+/K+ ATPase) enzyme assays indicated that P.A is a direct Na+/K+ ATPase inhibitor. P.A showed potent cytotoxic effects in NSCLC cells at nanomolar levels. Treatment mechanism studies indicated that P.A elevated Ca2+ levels, activated the AMPK pathway and downregulated phosphorylation of ACC and mTOR. Subsequently, P.A increased death receptor 4 (DR4) expression and downregulated NF–κB. Interestingly, P.A selectively suppressed EGFR activation in EGFR mutant cells but not in EGFR wild-type cells. In vivo, P.A significantly suppressed tumor growth in nude mice compared to vehicle-treated mice. Compared with the Afatinib treatment group, P.A displayed less pharmaceutical toxicity, as the body weight of mice treated with P.A did not decrease as much as those treated with Afatinib. Consistent changes in protein levels were obtained from western blotting analysis of tumors and cell lines. Immunohistochemistry analysis of the tumors from P.A-treated mice showed a significant suppression of EGFR phosphorylation (Tyr 1173) and reduction of the cell proliferation marker Ki-67. Taken together, our results suggest that P.A is a promising anti-cancer therapeutic candidate for NSCLC.
Nuclear PTEN safeguards pre-mRNA splicing to link Golgi apparatus for its tumor suppressive role
Authors: Shen Shao-Ming , Ji Yan , Zhang Cheng , Dong Shuang-Shu , Yang Shuo , Xiong Zhong , Ge Meng-Kai , Yu Yun , Xia Li , Guo Meng , Cheng Jin-Ke , Liu Jun-Ling , Yu Jian-Xiu , Chen Guo-Qiang 
Published: June 2018

AbstractDysregulation of pre-mRNA alternative splicing (AS) is closely associated with cancers. However, the relationships between the AS and classic oncogenes/tumor suppressors are largely unknown. Here we show that the deletion of tumor suppressor PTEN alters pre-mRNA splicing in a phosphatase-independent manner, and identify 262 PTEN-regulated AS events in 293T cells by RNA sequencing, which are associated with significant worse outcome of cancer patients. Based on these findings, we report that nuclear PTEN interacts with the splicing machinery, spliceosome, to regulate its assembly and pre-mRNA splicing. We also identify a new exon 2b in GOLGA2 transcript and the exon exclusion contributes to PTEN knockdown-induced tumorigenesis by promoting dramatic Golgi extension and secretion, and PTEN depletion significantly sensitizes cancer cells to secretion inhibitors brefeldin A and golgicide A. Our results suggest that Golgi secretion inhibitors alone or in combination with PI3K/Akt kinase inhibitors may be therapeutically useful for PTEN-deficient cancers.
18β-Glycyrrhetinic-acid-mediated unfolded protein response induces autophagy and apoptosis in hepatocellular carcinoma
Authors: Chen Jin , Zhang Zhao-qi , Song Jia , Liu Qiu-meng , Wang Chao , Huang Zhao , Chu Liang , Liang Hui-fang , Zhang Bi-xiang , Chen Xiao-ping 
Published: June 2018

Abstract18β-Glycyrrhetinic acid (GA) is the active ingredient of the traditional Chinese medicine, Glycyrrhrzae Radix et Rhizoma. Here, we explored the effects of GA on hepatocellular carcinoma (HCC) in vitro and in vivo and the underlying molecular mechanisms. We confirmed that GA suppressed proliferation of various HCC cell lines. Treatment of GA caused G0/G1 arrest, apoptosis and autophagy in HCC cells. GA-induced apoptosis and autophagy were mainly due to the unfolded protein response. We compared the roles of the ATF4/CHOP and IRE1α/XBP1s UPR pathways, which were both induced by GA. The ATF4/CHOP cascade induced autophagy and was indispensable for the induction of apoptosis in GA-treated HCC cells. In contrast, the IRE1α/XBP1s cascade protected HCC cells from apoptosis in vitro and in vivo induced by GA. Despite this, activation of autophagy protected HCC cells from apoptosis induced by GA. We concluded that pharmacological inhibition of autophagy or IRE1α may be of benefit to enhance the antitumor activity of GA.
Light-microgel interaction in resonant nanostructures
Authors: Giaquinto M. , Ricciardi A. , Aliberti A. , Micco A. , Bobeico E. , Ruvo M. , Cusano A. 
Published: June 2018

AbstractCombination of responsive microgels and photonic resonant nanostructures represents an intriguing technological tool for realizing tunable and reconfigurable platforms, especially useful for biochemical sensing applications. Interaction of light with microgel particles during their swelling/shrinking dynamics is not trivial because of the inverse relationships between their size and refractive index. In this work, we propose a reliable analytical model describing the optical properties of closed-packed assembly of surface-attached microgels, as a function of the external stimulus applied. The relationships between the refractive index and thickness of the equivalent microgel slab are derived from experimental observations based on conventional morphological analysis. The model is first validated in the case of temperature responsive microgels integrated on a plasmonic lab-on-fiber optrode, and also implemented in the same case study for an optical responsivity optimization problem. Overall, our model can be extended to other photonic platforms and different kind of microgels, independently from the nature of the stimulus inducing their swelling.
Straight motion of half-integer topological defects in thin Fe-N magnetic films with stripe domains
Authors: Fin S. , Silvani R. , Tacchi S. , Marangolo M. , Garnier L.-C. , Eddrief M. , Hepburn C. , Fortuna F. , Rettori A. , Pini M. G. , Bisero D. 
Published: June 2018

AbstractIn thin magnetic films with perpendicular magnetic anisotropy, a periodic “up-down” stripe-domain structure can be originated at remanence, on a mesoscopic scale (~100 nm) comparable with film thickness, by the competition between short-range exchange coupling and long-range dipolar interaction. However, translational order is perturbed because magnetic edge dislocations are spontaneously nucleated. Such topological defects play an important role in magnetic films since they promote the in-plane magnetization reversal of stripes and, in superconductor/ferromagnet hybrids, the creation of superconducting vortex clusters. Combining magnetic force microscopy experiments and micromagnetic simulations, we investigated the motion of two classes of magnetic edge dislocations, randomly distributed in an $${{\rm{N}}}_{2}^{+}$$

N

2

+

-implanted Fe film. They were found to move in opposite directions along straight trajectories parallel to the stripes axis, when driven by a moderate dc magnetic field. Using the approximate Thiele equation, analytical expressions for the forces acting on such magnetic defects and a microscopic explanation for the direction of their motion could be obtained. Straight trajectories are related to the presence of a periodic stripe domain pattern, which imposes the gyrotropic force to vanish even if a nonzero, half-integer topological charge is carried by the defects in some layers across the film thickness.
Tannin-rich extracts from Lannea stuhlmannii and Lannea humilis (Anacardiaceae) exhibit hepatoprotective activities in vivo via enhancement of the anti-apoptotic protein Bcl-2
Authors: Sobeh Mansour , Mahmoud Mona F. , Hasan Rehab A. , Abdelfattah Mohamed A. O. , Sabry Omar M. , Ghareeb Mosad A. , El-Shazly Assem M. , Wink Michael 
Published: June 2018

AbstractThe potential hepatoprotective activities of two Lannea species were explored in vivo. Furthermore, the binding activities of their main polyphenols to the antiapoptotic protein Bcl-2 were investigated. Based on HPLC-MS/MS results, 22 secondary metabolites were characterized in L. stuhlmannii (mainly tannins), while 20 secondary metabolites (mainly sulphated tannins) were identified in L. humilis. Both extracts exhibited substantial antioxidant activities in vitro and counteracted D-galactosamine induced intoxication in rats in vivo and increased the total antioxidant capacity (TAC) of liver tissues. In addition to reducing the elevated levels of AST and total bilirubin, both extracts significantly attenuated the deleterious histopathologic changes in liver after D-galactosamine-intoxication. Also, both extracts protected hepatocytes from apoptotic cell death and increased the expression of the anti-apoptotic protein Bcl-2. The identified compounds from both extracts can bind to the Bcl-2: Bim (BH3) interface with an appreciable binding free energy. Hydrogen and ionic bonds and hydrophobic interactions with amino acid residues in the hydrophobic face of Bim (BH3) domain were discovered. To sum up, L. humilis and L. stuhlmanni exhibited promising hepatoprotective activities in vivo against D-GalN-induced liver injury and their hepatoprotection is due to the antioxidant and anti-apoptotic effects of tannins and proanthocyanidins.
Buffalo nasal odorant-binding protein (bunOBP) and its structural evaluation with putative pheromones
Authors: Muthukumar Subramanian , Rajesh Durairaj , Selvam Ramu Muthu , Saibaba Ganesan , Suvaithenamudhan Suvaiyarasan , Akbarsha Mohammad Abdulkader , Padmanabhan Parasuraman , Gulyas Balazs , Archunan Govindaraju 
Published: June 2018

AbstractPheromones are odoriferous volatile chemical cues produced by animals for communication among conspecifics so as to regulate their social behaviors. In general, the odor compounds are recognized by receptors in the nasal cavity. Odorant-binding protein (OBP), a lipocalin family protein, mediates the air-borne odor cues to nasal receptors through nasal mucus. The presence of OBP in several mammalian species is well documented but to-date there is no report of a nasal OBP in buffalo. Hence, the present study was undertaken to investigate if OBP is present in buffalo nasal mucus. Uni- and two-dimensional gel electrophoresis of the nasal mucus suggested the presence of OBP, which was confirmed using mass spectrometry. In silico homology model of the OBP was generated and its structural similarity with other mammalian OBPs was assessed. Finally, molecular-docking and -dynamics simulations analysis revealed the efficiency of buffalo nasal OBP (bunOBP) to bind with buffalo pheromones as well as other reported chemical cues. Taken together, the occurrence of nasal OBP in buffalo and its putative role in odor binding are reported for the first time. The potential association of this protein with estrus-specific volatiles could be taken to advantage for non-invasive detection of estrus in buffaloes.
Mapping the resilience of chemosynthetic communities in hydrothermal vent fields
Authors: Suzuki Kenta , Yoshida Katsuhiko , Watanabe Hiromi , Yamamoto Hiroyuki 
Published: June 2018

AbstractHydrothermal vent fields are vulnerable to natural disturbances, such as volcanic activity, and are currently being considered as targets for mineral mining. Local vent communities are linked by pelagic larval dispersal and form regional metacommunities, nested within a number of biogeographic provinces. Larval supply depends on the connectivity of the dispersal networks, and affects recoverability of communities from disturbances. However, it is unclear how the dispersal networks contribute to recoverability of local communities. Here, we integrated a population dynamics model and estimation of large scale dispersal networks. By simulating disturbances to vent fields, we mapped recoverability of communities in 131 hydrothermal vent fields in the western Pacific Ocean. Our analysis showed substantial variation in recovery time due to variation in regional connectivity between known vent fields, and was not qualitatively affected by potential larval recruitment from unknown vent fields. In certain cases, simultaneous disturbance of a series of vent fields either delayed or wholly prevented recovery. Our approach is applicable to a dispersal network estimated from genetic diversity. Our method not only reveals distribution of recoverability of chemosynthetic communities in hydrothermal vent fields, but is also a practical tool for planning conservation strategies.