bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemical escape of oxygen from Mars: First results from MAVEN in situ data
Authors: Lillis Robert J. , Deighan Justin , Fox Jane L. , Bougher Stephen W. , Lee Yuni , Combi Michael R. , Cravens Thomas E. , Rahmati Ali , Mahaffy Paul R. , Benna Mehdi , Elrod Meredith K. , McFadden James P. , Ergun Robert. E. , Andersson Laila , Fowler Christopher M. , Jakosky Bruce M. , Thiemann Ed , Eparvier Frank , Halekas Jasper S. , Leblanc François , Chaufray Jean‐Yves 
Published: February 2017

AbstractPhotochemical escape of atomic oxygen is thought to be one of the dominant channels for Martian atmospheric loss today and played a potentially major role in climate evolution. Mars Atmosphere and Volatile Evolution Mission (MAVEN) is the first mission capable of measuring, in situ, the relevant quantities necessary to calculate photochemical escape fluxes. We utilize 18 months of data from three MAVEN instruments: Langmuir Probe and Waves, Neutral Gas and Ion Mass Spectrometer, and SupraThermal And Thermal Ion Composition. From these data, we calculate altitude profiles of the production rate of hot oxygen atoms from the dissociative recombination of O2+ and the probability that such atoms will escape the Mars atmosphere. From this, we determine escape fluxes for 815 periapsis passes. Derived average dayside hot O escape rates range from 1.2 to 5.5 × 1025 s−1, depending on season and EUV flux, consistent with several pre‐MAVEN predictions and in broad agreement with estimates made with other MAVEN measurements. Hot O escape fluxes do not vary significantly with dayside solar zenith angle or crustal magnetic field strength but depend on CO2 photoionization frequency with a power law whose exponent is 2.6 ± 0.6, an unexpectedly high value which may be partially due to seasonal and geographic sampling. From this dependence and historical EUV measurements over 70 years, we estimate a modern‐era average escape rate of 4.3 × 1025 s−1. Extrapolating this dependence to early solar system, EUV conditions gives total losses of 13, 49, 189, and 483 mbar of oxygen over 1–3 and 3.5 Gyr, respectively, with uncertainties significantly increasing with time in the past.
Early‐Middle Triassic high Sr/Y granitoids in the southern Central Asian Orogenic Belt: Implications for ocean closure in accretionary orogens
Authors: Li Shan , Chung Sun‐Lin , Wilde Simon A. , Jahn Bor‐Ming , Xiao Wen‐Jiao , Wang Tao , Guo Qian‐Qian 
Published: February 2017

AbstractThe key to defining the termination of accretion in an accretionary orogen is to recognize the initial magmatic processes that are generated at the time of ocean closure. We present new age, geochemical, and isotopic data for magmatic rocks related to terminal collision along the Solonker‐Xar Moron suture zone in the southern Central Asian Orogenic Belt (CAOB) that record such processes following closure of the Paleo‐Asian Ocean. These magmatic rocks were emplaced in the Early‐Middle Triassic (251–245 Ma) and show high Sr/Y signatures. Their low MgO, Cr, and Ni contents and variable whole‐rock εNd(t) values (+5.8 to −5.3), together with the range in zircon εHf(t) (+15.6 to −9.8) and δ18O values (5.1 to 7.9‰), indicate an origin from partial melting of juvenile lower crustal rocks with some old components, including supracrustal recycling under garnet amphibolite facies conditions. Our data, along with available geological and geophysical evidence, lead us to propose a model of final oceanic contraction in the southern CAOB, resulting in sublinear distribution of high Sr/Y melts along the resultant collision zone, thus defining the onset of postaccretionary processes in the southern CAOB. The identification of collision‐related high Sr/Y granitoids from the southern CAOB not only reveals the magmatic process in response to the final episode of orogenic evolution in the CAOB accretionary collision zone but also constrains how and when an archipelago‐type accretionary orogen is terminated.
A rover's geologic field campaign: Exploration of the Kimberley by Curiosity
Authors: Minitti Michelle E. 
Published: February 2017

AbstractThe Mars Science Laboratory Curiosity rover undertook comprehensive exploration of the Kimberley waypoint within Gale crater, Mars in order to understand its context within the larger geologic picture of Gale crater and its evidence for past Martian habitability. Coordinated observations from Curiosity's rich science payload revealed important insights into new Martian crustal compositions, the prevalence and diversity of sedimentary processes within Gale crater, and surface erosion rates. Exploration at the Kimberley, in part informed by a decade of orbital observations of Gale crater, underscored the critical synergy between landed and orbital observations and furthered understanding of complex geological processes on Mars.
Selective localization of organic montmorillonite nanoparticles in multilayered high‐density polyethylene/polyamide 6 composites
Authors: Xie Gaoyi , Yu Jie , Qin Shuhao , Sun Jing , Yang Zhao , Wei Liangqiang , Ji Yubi , He Wentao , Xu Guomin 
Published: February 2017

AbstractTo achieve a selective localization of nanoparticles in multilayered two‐component polymer blends, an intentional two‐step process, first pre‐compounding and then co‐extruding, was employed to prepare multilayered high‐density polyethylene (HDPE)/polyethylene‐grafted maleic anhydride (PE‐g‐MAH)/organic montmorillonite (OMMT)‐polyamide 6 (PA6) nanocomposites. The dispersion ofOMMTwas evaluated by transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The results showed that the localization ofOMMTwas tunable with different content ofPE‐g‐MAH. By comparing the localization ofOMMTin a single‐layered nanocomposite with that in the multilayered nanocomposites, as well as by theoretically calculating wetting coefficients of the multilayered nanocomposites, the migration mechanism ofOMMTwas revealed. As demonstrated by differential scanning calorimetry (DSC), transmission rate measurement and tensile test, the selective localization ofOMMTin the multilayered nanocomposites could increase crystallinity degree of the two‐polymer components, enhancing oxygen barrier property and tensile strength of the nanocomposties.
Trends in Volunteer Mentoring in the United States: Analysis of a Decade of Census Survey Data
Authors: Raposa Elizabeth B. , Dietz Nathan , Rhodes Jean E. 
Published: February 2017

AbstractOver the past decade, considerable resources have been devoted to recruiting volunteer mentors and expanding mentoring programs. It is unclear whether these efforts have helped to counter the broader national trends of declining volunteer rates. The current study uses data from the Volunteering Supplement of the Current Population Survey (CPS), sponsored by the U.S. Census Bureau and U.S. Bureau of Labor Statistics, to explore population‐level trends in mentoring over the past decade. Results suggest that mentoring rates have remained relatively stable over the past decade, but that the population of mentors has changed somewhat in terms of age, ethnicity, educational background, and region of the United States. In addition, certain sectors of the mentor population show higher rates of attrition from 1 year to the next. Findings have important implications for the development of recruitment, training, and mentor support practices within mentoring organizations, as well as policies designed to meet the needs of at‐risk youth in the U.S.
A giant among dwarfs: a new species of galago (Primates: Galagidae) from Angola
Authors: Svensson Magdalena S. , Bersacola Elena , Mills Michael S. L. , Munds Rachel A. , Nijman Vincent , Perkin Andrew , Masters Judith C. , Couette Sébastien , Nekaris K. Anne‐Isola , Bearder Simon K. 
Published: February 2017

AbstractObjectivesBased on vocalization recordings of an unknown galago species, our main objectives were to compare morphology and call structure with known closely‐related taxa and describe a new species of galago.Materials and methodsWe conducted field surveys in three forest habitats along the escarpment region in western Angola (Kumbira Forest, Bimbe Area, and Northern Scarp Forest), and examined galago specimens from museums worldwide. We digitized and analyzed calls using Avisoft SASLab Pro software. We also compared museum specimens from Angola with other Galago and Galagoides specimens, and conducted comparative analyses (ANOVA and between group principle component analysis) based on a set of twelve linear measurements of skulls and teeth.ResultsWe describe the new species to which we give the name Angolan dwarf galago, Galagoides kumbirensis sp. nov. The new species has a loud and characteristic crescendo call, used by other Galagoides spp. (sensu stricto) in West Africa to attract companions and repel rivals. However, this call shows species‐typical differences from its closest relatives. Galagoides kumbirensis sp. nov. is also distinguished by differences in the skull morphology, pelage color and facial markings, as well as a larger body size, similar to that of Galago moholi, which is not known to be sympatric.ConclusionThis discovery points to the importance of Angolan forests as refuges for endemic biodiversity. These forests are under severe threat from overexploitation, and there is an urgent need to establish conservation measures and designate protected areas.
Pathogenic role of anti–signal recognition protein and anti–3‐Hydroxy‐3‐methylglutaryl‐CoA reductase antibodies in necrotizing myopathies: Myofiber atrophy and impairment of muscle regeneration in necrotizing autoimmune myopathies
Authors: Arouche‐Delaperche Louiza , Allenbach Yves , Amelin Damien , Preusse Corinna , Mouly Vincent , Mauhin Wladimir , Tchoupou Gaelle Dzangue , Drouot Laurent , Boyer Olivier , Stenzel Werner , Butler‐Browne Gillian , Benveniste Olivier 
Published: February 2017

ObjectiveImmune‐mediated necrotizing myopathies (IMNM) may be associated with either anti–signal recognition protein (SRP) or anti–3‐hydroxy‐3‐methylglutaryl‐CoA reductase (HMGCR) antibodies (Abs), and the titer of these Abs is correlated with disease activity. We investigated whether anti‐SRP and anti‐HMGCR Abs could be involved in muscle damage.MethodsMuscle biopsies of patients were analyzed for atrophy and regeneration by measuring fiber size and by performing immunostaining of neonatal myosin heavy chain. To further understand the role of the Abs in the pathology, we performed muscle cell coculture with the Abs. Atrophy and regeneration were evaluated based on the myotube surface area as well as gene and cytokine profiles.ResultsIn muscle biopsies of patients with anti‐SRP+ and anti‐HMGCR+ Abs, a large number of small fibers corresponding to both atrophic and regenerating fibers were observed. In vitro, anti‐SRP and anti‐HMGCR Abs induced muscle fiber atrophy and increased the transcription of MAFbx and TRIM63. In addition, the muscle fiber atrophy was associated with high levels of inflammatory cytokines: tumor necrosis factor, interleukin (IL)‐6, and reactive oxygen species. In the presence of anti‐SRP or anti‐HMGCR Abs, mechanisms involved in muscle regeneration were also impaired due to a defect of myoblast fusion. This defect was associated with a decreased production of IL‐4 and IL‐13. The addition of IL‐4 and/or IL‐13 totally rescued fusion capacity.InterpretationThese data show that molecular mechanisms of atrophy and regeneration are affected and contribute to loss of muscle function occurring in IMNM. This emphasizes the potential interest of targeted therapies addressing these mechanisms. Ann Neurol 2017;81:538–548
Highly dispersed copper/ppm palladium nanoparticles as novel magnetically recoverable catalyst for Suzuki reaction under aqueous conditions at room temperature
Authors: Lamei Kamran , Eshghi Hossein , Bakavoli Mehdi , Rostamnia Sadegh 
Published: February 2017

An efficient procedure based on arginine‐modified Fe3O4@carbon magnetic nanoparticles (FCA MNPs) with highly dispersed copper nanoparticles (Cu NPs) and 92.8 ppm of Pd is reported for room temperature Suzuki reaction. For enhancing the activity of this Cu‐based heterogeneous catalyst, special arginine amino acid as a ligand with high content of heteroatoms was immobilized onto the Fe3O4@carbon MNPs to increase the electron density. Cu(II) ions were then loaded on the surface of the FCA MNPs and reduced to achieve uniformly dispersed Cu NPs. An aqueous mixture of metal hydroxides such as KOH, Ba(OH)2, Ca(OH)2, Mg(OH)2 as a green, non‐toxic and basic medium was used for the Suzuki reaction at room temperature. This catalyst could also be recovered and reused with no loss of activity over six successful runs.
Miscible blends of biobased poly(lactide) with poly(methyl methacrylate): Effects of chopped glass fiber incorporation
Authors: Cousins Dylan S. , Lowe Corinne , Swan Dana , Barsotti Robert , Zhang Mingfu , Gleich Klaus , Berry Derek , Snowberg David , Dorgan John R. 
Published: February 2017

ABSTRACTPoly(lactide) (PLA) and poly(methyl methacrylate) (PMMA) are melt compounded with chopped glass fiber using laboratory scale twin‐screw extrusion. Physical properties are examined using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA), tensile testing, impact testing, X‐ray computed tomography (CT) scanning, and field emission scanning electron microscopy (FE‐SEM). Molecular weight is determined using gel permeation chromatography (GPC). Miscibility of the blends is implied by the presence of a single glass transition temperature and homogeneous morphology. PLA/PMMA blends tend to show positive deviations from a simple linear mixing rule in their mechanical properties (e.g., tensile toughness, modulus, and stress at break). The addition of 40 wt % glass fiber to the system dramatically increases physical properties. Across all blend compositions, the tensile modulus increases from roughly 3 GPa to roughly 10 GPa. Estimated heat distortion temperatures (HDTs) are also greatly enhanced; the pure PLA sample HDT increases from 75 °C to 135 °C. Fiber filled polymer blends represent a sustainable class of earth abundant materials which should prove useful across a range of applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44868.
Hydroxypropyl cellulose‐based esters for thermal energy storage by grafting with palmitic‐stearic binary acids
Authors: Chen Weiwang , Weng Wenguo , Fu Ming 
Published: February 2017

ABSTRACTFatty acid mixed esters (i.e., HPCMEs) with the onset phase change temperature around 32 °C were successfully synthesized by grafting palmitic‐stearic binary acids (PA‐SA) onto hydroxypropyl cellulose (HPC). The effects of reaction time, reaction temperature, initial ratio of reactants, and stirring speed on grafting ratio (GR) were explored. Characterizations by FTIR, 1H NMR, DSC, and TGA were also performed to investigate their structure, thermal storage, and decomposition behavior. The results reveal that the prepared HPCMEs as thermoplastic copolymers exhibit high enthalpies, good repeatability, and enhanced thermal resistance properties. With the introduction of HPC rigid skeletons, gradual volatilization of fatty acids during use is well solved. The prepared HPCMEs thus are expected to have wide prospects for thermal energy storage owing to their proper phase change temperatures and excellent integrated performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44949.
Structural changes in cartilage and collagen studied by high temperature Raman spectroscopy
Authors: Fields Mark , Spencer Nicholas , Dudhia Jayesh , McMillan Paul F. 
Published: February 2017

AbstractUnderstanding the high temperature behavior of collagen and collagenous tissue is important for surgical procedures and biomaterials processing for the food, pharmaceutical, and cosmetics industries. One primary event for proteins is thermal denaturation that involves unfolding the polypeptide chains while maintaining the primary structure intact. Collagen in the extracellular matrix of cartilage and other connective tissue is a hierarchical material containing bundles of triple‐helical fibers associated with water and proteoglycan components. Thermal analysis of dehydrated collagen indicates irreversible denaturation at high temperature between 135°C and 200°C, with another reversible event at ∼60‐80°C for hydrated samples. We report high temperature Raman spectra for freeze‐dried cartilage samples that show an increase in laser‐excited fluorescence interpreted as conformational changes associated with denaturation above 140°C. Spectra for separated collagen and proteoglycan fractions extracted from cartilage indicate the changes are associated with collagen. The Raman data also show appearance of new features indicating peptide bond hydrolysis at high temperature implying that molecular H2O is retained within the freeze‐dried tissue. This is confirmed by thermogravimetric analysis that show 5‐7 wt% H2O remaining within freeze‐dried cartilage that is released progressively upon heating up to 200°C. Spectra obtained after exposure to high temperature and re‐hydration following recovery indicate that the capacity of the denatured collagen to re‐absorb water is reduced. Our results are important for revealing the presence of bound H2O within the collagen component of connective tissue even after freeze‐drying and its role in denaturation that is accompanied by or perhaps preceded by breakdown of the primary polypeptide structure.
microRNA‐216b inhibits cell proliferation and migration in human melanoma by targeting FOXM1 in vitro and in vivo
Authors: Sun Mengyao , Wang Xiaopeng , Tu Chen , Wang Shuang , Qu Jianqiang , Xiao Shengxiang 
Published: February 2017

AbstractMicroRNAs (miRNAs) play an increasingly important role in cancer growth by coordinately suppressing genes that control cell migration, proliferation, and invasion. The above results can be achieved through the regulation of gene expression by miRNAs by suppressing translation or the direct sequence‐specific degradation of the targeted mRNA. In the present study, we indicate that the expression of miR‐216b could be effectively repressed both in human melanoma tissues through a comparison with primary melanoma and in human melanoma cell lines through a comparison with a normal human keratinocyte line. Moreover, miR‐216b induced a clear decrease in melanoma cell proliferation and migration in vitro. Forkhead box M1 (FOXM1) was confirmed as a target gene of miR‐216b, and the overexpression of miR‐216b markedly repressed the luciferase activity of reporter plasmids containing the FOXM1 3′‐UTR (untranslated region). Furthermore, miR‐216b suppressed melanoma cell growth in nude mice in vivo, with the effects of miR‐216b overexpression on melanoma cell growth and proliferation reversed by FOXM1 overexpression. The results demonstrated that miR‐216b is a tumor suppressor in melanoma, identified the FOXM1 signaling pathway as a target of miR‐216b action, and suggested a potential therapeutic role for miR‐216b in melanoma.
The Influence of Alcohols in Driving the Morphology of Magnesium Chloride Nanocrystals
Authors: Thushara K. S. , D'Amore Maddalena , Piovano Alessandro , Bordiga Silvia , Groppo Elena 
Published: February 2017

AbstractMgCl2 nanocrystals prepared in the presence of methanol and ethanol were characterized by complementing surface‐science tools with a systematic quantum‐mechanical investigation of the stability order (in terms of Gibbs free energy) of different MgCl2 surfaces in the presence of the two alcohols. Both alcohols drastically change the overall stability and the stability order of the exposed surfaces, mainly as a consequence of the entropic contribution to the Gibbs free energy, hence inhibiting or promoting crystal growth in certain directions. The environment‐dependent occurrence of the MgCl2 surfaces may influence the structure and properties of the supported TixCl4−x sites in the MgCl2/TiCl4 precatalyst, which has important implications in the design of morphologically controlled Ziegler–Natta catalysts.
Nb‐Doped Rutile TiO2 Mesocrystals with Enhanced Lithium Storage Properties for Lithium Ion Battery
Authors: Lan Tongbin , Zhang Weifeng , Wu Nae‐Lih , Wei Mingdeng 
Published: February 2017

AbstractA homogeneous Nb‐doped rutile TiO2 mesocrystal material was synthesized successfully through a facile hydrothermal route. The incorporation of Nb5+ not only promotes the crystallization of the building subunits of the rutile TiO2 mesocrystal, but also improves the electrochemical performance at higher current rates. A capacity of 96.3 mAh g−1 at a current density as high as 40 C and an excellent long‐term cycling stability with a capacity loss of approximately 0.006 % per cycle at 5 C could be achieved when an appropriate amount of Nb5+ was doped into rutile TiO2 mesocrystal. The reasons for the improvement of rate capability may be attributed to the enhancement of electronic conductivity, Li‐ion diffusion kinetics, and the surface storage property for the Nb‐doped rutile TiO2 mesocrystal.
Orthogonal Click Postfunctionalization of Alternating Copolymers Prepared by Nitroxide‐Mediated Polymerization
Authors: Tesch Matthias , Kudruk Sergej , Letzel Matthias , Studer Armido 
Published: February 2017

AbstractNitroxide‐mediated polymerization (NMP) was applied to prepare alternating copolymers using 1,1,1,3,3,3‐hexafluoroisopropyl acrylate (HFIPA) 1 and ((6‐trimethylsilyl)‐hex‐5‐yn‐1‐yl)vinyl ether (THVE) 2 as monomers. The alternating sequence of the resulting poly(HFIPA‐alt‐THVE) 3 was proved by using tandem mass spectrometry (MS/MS) and further supported by 1H NMR spectroscopy. Alternating alkyne and activated ester moieties of copolymer 3 were further functionalized with organic azides and amines using sequential Cu‐catalyzed azide–alkyne click (CuAAC) and amidation reactions, providing dually functionalized poly(acrylamide‐alt‐triazole) polymers 5. Water‐soluble alternating poly(acrylic acid‐alt‐triazole) copolymers 9 were obtained by saponification of HFIP esters. 1H and 19F NMR spectroscopy, IR spectroscopy as well as gel permeation chromatography (GPC) were used to characterize the polymers before and after functionalization.
Carbazole‐Linked Near‐Infrared Aza‐BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep‐Tissue Imaging
Authors: Gawale Yogesh , Adarsh Nagappanpillai , Kalva Sandeep Kumar , Joseph Joshy , Pramanik Manojit , Ramaiah Danaboyina , Sekar Nagaiyan 
Published: February 2017

AbstractFour new N‐ethylcarbazole‐linked aza‐boron‐dipyrromethene (aza‐BODIPY) dyes (8 a,b and 9 a,b) were synthesized and characterized. The presence of the N‐ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near‐infrared region, λ≈650–730 nm, of the electromagnetic spectrum. These dyes possess strong molar absorptivity in the range of 3–4×104 m−1 cm−1 with low fluorescence quantum yields. The triplet excited state and singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core‐iodinated dyes 9 a,b showed excellent triplet quantum yields of about 90 and 75 %, with singlet oxygen generation efficiency of about 70 and 60 % relative to that of the parent dyes. Derivatives 8 a,b showed dual absorption profiles, in contrast to dyes 9 a,b, which had the characteristic absorption band of aza‐BODIPY dyes. DFT calculations revealed that the electron density was spread over the iodine and dipyrromethene plane of 9 a,b, whereas in 8 a,b the electron density was distributed on the carbazole group and dipyrromethene plane of aza‐BODIPY. The uniqueness of these aza‐BODIPY systems is that they exhibit efficient triplet‐state quantum yields, high singlet oxygen generation yields, and good photostability. Furthermore, the photoacoustic (PA) characteristics of these aza‐BODIPY dyes was explored, and efficient PA signals for 8 a were observed relative to blood serum with in vitro deep‐tissue imaging, thereby confirming its use as a promising PA contrast agent.