bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Example of Hydrogen Bonding to Platinum Hydride
Authors: Filippov Oleg A. , Kirkina Vladislava A. , Belkova Natalia V. , Stoccoro Sergio , Zucca Antonio , Babakhina Galina M. , Epstein Lina M. , Shubina Elena S. 
Published: June 2013

Abstract
The interaction between various proton donors (indole, CF3CH2OH, (CF3)2CHOH, (CF3)3COH) and (NNC)PtH hydrido complex (NNC-H=6-(1,1'-dimethylbenzyl)-2,2'-bipyridine) was investigated through low-temperature IR and NMR spectroscopy in combination with density functional theory calculations at the M06 level of theory. The experiment shows formation of very weak hydrogen bonded complexes (Δ HºHB
ca. -1.0 kcal mol-1), which undergo subsequent proton transfer surprisingly easy. Computational analysis of the hydrogen bonded complexes geometry, electronic parameters (obtained by NBO and AIM analysis), and orbital interaction energies shows that all the complexes are better described as bonded to the metal atom. At that in case of weak alcohols (CH3OH, TFE) there is also the additional interaction with the hydride ligand. These computational results allow explaining the observed experimental trends and give the first example of hydrogen bonding to a metal atom in the presence of hydride ligand.
Identity by Descent: Variation in Meiosis, Across Genomes, and in Populations
Authors: Thompson Elizabeth A 
Published: June 2013

AbstractGene identity by descent (IBD) is a fundamental concept that underlies genetically mediated similarities among relatives. Gene IBD is traced through ancestral meioses and is defined relative to founders of a pedigree, or to some time point or mutational origin in the coalescent of a set of extant genes in a population. The random process underlying changes in the patterns of IBD across the genome is recombination, so the natural context for defining IBD is the ancestral recombination graph (ARG), which specifies the complete ancestry of a collection of chromosomes. The ARG determines both the sequence of coalescent ancestries across the chromosome and the extant segments of DNA descending unbroken by recombination from their most recent common ancestor (MRCA). DNA segments IBD from a recent common ancestor have high probability of being of the same allelic type. Non-IBD DNA is modeled as of independent allelic type, but the population frame of reference for defining allelic independence can vary. Whether of IBD, allelic similarity, or phenotypic covariance, comparisons may be made to other genomic regions of the same gametes, or to the same genomic regions in other sets of gametes or diploid individuals. In this review, I present IBD as the framework connecting evolutionary and coalescent theory with the analysis of genetic data observed on individuals. I focus on the high variance of the processes that determine IBD, its changes across the genome, and its impact on observable data.
Autophagic Processes in Yeast: Mechanism, Machinery and Regulation
Authors: Reggiori Fulvio , Klionsky Daniel J 
Published: June 2013

Abstract
Autophagy refers to a group of processes that involve degradation of cytoplasmic components including cytosol, macromolecular complexes, and organelles, within the vacuole or the lysosome of higher eukaryotes. The various types of autophagy have attracted increasing attention for at least two reasons. First, autophagy provides a compelling example of dynamic rearrangements of subcellular membranes involving issues of protein trafficking and organelle identity, and thus it is fascinating for researchers interested in questions pertinent to basic cell biology. Second, autophagy plays a central role in normal development and cell homeostasis, and, as a result, autophagic dysfunctions are associated with a range of illnesses including cancer, diabetes, myopathies, some types of neurodegeneration, and liver and heart diseases. That said, this review focuses on autophagy in yeast. Many aspects of autophagy are conserved from yeast to human; in particular, this applies to the gene products mediating these pathways as well as some of the signaling cascades regulating it, so that the information we relate is relevant to higher eukaryotes. Indeed, as with many cellular pathways, the initial molecular insights were made possible due to genetic studies in Saccharomyces cerevisiae and other fungi.
Meiotic and Mitotic Recombination in Meiosis
Authors: Kohl Kathryn P , Sekelsky Jeff 
Published: June 2013

Abstract
Meiotic crossovers facilitate the segregation of homologous chromosomes and increase genetic diversity. The formation of meiotic crossovers was previously posited to occur via two pathways, with the relative use of each pathway varying between organisms; however, this paradigm could not explain all crossovers, and many of the key proteins involved were unidentified. Recent studies that identify some of these proteins reinforce and expand the model of two meiotic crossover pathways. The results provide novel insights into the evolutionary origins of the pathways, suggesting that one is similar to a mitotic DNA repair pathway and the other evolved to incorporate special features unique to meiosis.
Surface Chemical Analysis of Nanoparticles for Commercial Products and Devices
Authors: Baraton Marie-Isabelle 
Published: June 2013

ABSTRACTAmongst the list of the measurands specific to nanoparticles, size and shape definitely matter but surface chemistry is also often cited. While it is now largely recognized that surface composition, structure and reactivity are perhaps the dominant parameters controlling properties of nanoparticles, surface chemistry is one of the key characteristics of nanoparticles which is seldom or inappropriately evaluated, as it has been identified by international organizations (such as ISO, BIPM or CEN). The usual techniques for surface analysis of materials often require ultra-high vacuum (UHV) conditions and are hardly applicable to nanoparticles. Moreover, because the surface chemical composition and reactivity are dependent on the environmental conditions, the results obtained under UHV cannot be extrapolated to nanoparticles in ambient atmosphere or dispersed in liquids.After an analysis of the stakes and challenges in the surface characterization of nanoparticles and a very brief overview of the usual techniques for surface studies, this paper presents the performance of Fourier transform infrared (FTIR) spectroscopy to investigate surface chemical composition, surface reactivity and surface functionalization of nanoparticles. As illustrating examples, the results of the FTIR surface analysis of different kinds of ceramic nanoparticles are discussed with regard to several fields of applications.
Glass ceramic materials of the SiO2-CaO-MgO-Al2O3 system: Structural characterization and fluorine effect
Authors: Garza-García Mitzué , López-Cuevas Jorge , Hernández-Ibarra Oscar 
Published: June 2013

ABSTRACTGlass-Ceramic monoliths of the SiO2-CaO-MgO-Al2O3 system are obtained in this research. Due to its potential dual role as a flux and as a nucleating agent, two CaF2 levels (X = 3 and X = 6 mol.%) are investigated in the parent glass composition. Due to its good mechanical properties, we intend to obtain Diopside-type pyroxene [(Ca)(Mg,Al)(Al,Si)2O6] as the main crystalline phase in the synthesized glass-ceramics. Vickers microhardness (HV), density and type of crystallization are determined in the latter materials. The morphology and size of the Diopside crystals, as well as the crystallized fraction, are determined with the help of Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Both materials exhibit surface crystallization with Diopside-type pyroxene phase with acicular morphology homogeneously distributed in the glassy matrix. The specimen with the least amount of added fluorine shows the highest microhardness value, as well as the largest and thickest acicular crystals of Diopside-type pyroxene, the lowest apparent density and the largest crystallized fraction. Our results indicate that CaF2 added in the amounts used by us does not act as nucleating agent, but it does affect the growth of the acicular crystals of the Diopside-type pyroxene phase. This is attributed mainly to the effect of fluorine on the glass structure and properties. The materials developed in this study may be considered as viable alternatives for applications in abrasive and corrosive environments, as well as for substrates for metallic coatings, and for abrasion-resistant floor tiles and other structural applications.
Microtubular Teardrop Patterning and the Growing Process
Authors: Okeyoshi Kosuke , Ryuzo Kawamura , Osada Yoshihito 
Published: June 2013

ABSTRACTHere we show that microtubular bundles bend flexibly under a hydrodynamic flow to form teardrop patterns. In a highly concentrated microtubular solution, patterns of same-sized teardrops form according to the maximum critical curvature, which is determined by the specific rigidity of the microtubules. Our understanding is that these micropatterns grow when microtubular bundles with hydrodynamic flow energy are converted into stable teardrop patterns as a higher structure. This conversion is generated by the combined effect of multiple kinds of energy, including heat and hydrodynamic flow, as well as life systems. These self-generating patterns in a spatio-temporal stream are reminiscent of what the artist Edward Munch calleda scream of nature. We also envision that microtubular pattering with hierarchical structure will broaden the potential application of these geometrical structures and guide biomimetic material engineering towards areas such as integrated energy conversion, soft material patterning, and living signal transduction.
Use of Halloysite Nanotubes for the Production of Poly (lactic acid) Nanocomposites
Authors: Yeniova Canan E. , Ozkoc Guralp , Yilmazer Ulku 
Published: June 2013

ABSTRACTEnvironmental concerns emphasize the urgent need for the development of biodegradable polymers. In this study, poly (lactic acid) (PLA), being a biodegradable polymer matrix, was used together with poly (ethylene glycol) (PEG) to enhance its low toughness. In addition, the deterioration in mechanical properties owing to plasticization was tried to be overcome by addition of nanofiller. As nanofiller, two nanotubular halloysite (HNT) types, one local (ESAN HNT) and an imported one (Nanoclay HNT) supplied by Aldrich, were used. As the first step, characterization and purification of local HNT was performed. In the second step, plasticized and unplasticized PLA matrix composites containing 3, 5 and 10 wt % were prepared and their morphological and mechanical analysis were performed. Upon the addition of both ESAN HNT (local HNT) and Nanoclay HNT (imported HNT) no improvement was observed in the basal spacing of the clay layers owing to poor interaction between the matrix and the surface of the nanotubes which should be modified for better dispersion.
Indium plated carbon nanotubes pattern on flexible substrate defined by ink-jet printing
Authors: Xu Pingye , Hamilton Michael C. 
Published: June 2013

ABSTRACTCarbon nanotubes patterns of micron-level resolution have been achieved using inkjet printing of DNA and SDS assisted CNT dispersions. DNA/CNT film has a significantly higher resistance compared to SDS/CNT film. Taking advantage of the porous nature of printed SDS/CNT film after SDS removal, indium can be electroplated to fill the CNT network and form a CNT/In composite. The CNT/In composite was used as interconnect material. Reworkability and RF performance of In-plated CNT bump structures are studied and the results are presented.
The Role of Contact Adhesion in Friction and Wear of Graphene under Sliding Conditions
Authors: Sandoz-Rosado Emil J. , Terrell Elon J. 
Published: June 2013

ABSTRACTIn this study, the failure mechanisms of graphene under sliding are examined using atomistic simulations. A 6nm diameter diamond tip is slid (at a controlled normal load) over a graphene monolayer that is adhered to a semi-infinite silicon substrate. The impact of tip adhesion on the wear and frictional behavior of graphene is studied by comparing two diamond tips, one of which has been hydrogen-passivated and the other which is bare carbon. By contrasting the passivated and unpassivated tips, the interplay of adhesive and abrasive wear on the graphene membrane can also be compared. The results of this work indicate that chemical bonding between the tip and the graphene greatly exacerbates tearing in the graphene monolayer by plowing ahead of the indenter, causing material build-up and increasing effective contact area.
HIDDEN MINERAL DEPOSITS IN Cu-DOMINATED PORPHYRY-SKARN SYSTEMS: HOW RESOURCE REPORTING CAN OCCLUDE IMPORTANT MINERALIZATION TYPES WITHIN MINING CAMPS
Authors: Jowitt Simon M. , Mudd Gavin M. , Weng Zhehan 
Published: June 2013

Abstract
A single mining camp or ore deposit can contain multiple mineral deposit types but may have mineral reserves or resources classified by what a mining or mineral exploration company considers to be the dominant mineralization type in the area. In this paper, we summarize recent work on the challenges of reporting mineral deposits by geologic processes rather than by grades, tonnages, and mineral processing approaches. For example, the Ertsberg-Grasberg district of Indonesia contains several large skarn Cu-Au-Ag deposits, with the discovery outcrop as well as early production entirely in skarn. All early publications and resource descriptions refer to it as the Ertsberg district. Subsequent discovery of the giant Grasberg porphyry Cu-Au-Ag deposit led to the entire district being renamed Grasberg and classified as a porphyry deposit, despite the skarn-focused discovery and early production history of the deposit, as well as the presence of several large skarn deposits within the district. The Ok Tedi Cu-Au-Ag deposit of western Papua New Guinea also is generally thought of as a major porphyry Cu deposit, yet hosts both porphyry and skarn mineralization. Current reserve estimates indicate that the majority of the contained metal within the deposit is hosted by skarns rather than porphyry bodies. Thus, following the Grasberg example in terms of contained metal, Ok Tedi could be classified as a skarn rather than a porphyry deposit. In addition, comparatively minor mineral deposits can prove useful during exploration; this is exemplified by the large Au-Cu-Ag porphyry deposits at Cadia in Australia that were discovered by exploring modest skarn deposits using the Ertsberg-Grasberg skarn-porphyry model. Here, we extend a recent global compilation of economic Cu mineral resources by analyzing cumulative production and reserve-resource data for Ertsberg-Grasberg, Ok Tedi, and Cadia, and provide a brief review of a number of other Cu projects that contain multiple mineralization types. Overall, in order to help inform exploration strategies as well as facilitate the development of more comprehensive and accurate mineral deposit models, there is clearly positive value for the mineral exploration and mining industry in reporting ore reserves and mineral resources by mineralization type.
Spatial Variation in Platinum Group Element Concentrations in Ore-Bearing Komatiite at the Long-Victor Deposit, Kambalda Dome, Western Australia: Enlarging the Footprint of Nickel Sulfide Orebodies
Authors: Barnes Stephen J. , Heggie Geoffrey J. , Fiorentini Marco L. 
Published: June 2013

Abstract
The detectable footprints of komatiite-hosted nickel sulfide deposits are typically very small, but can potentially be enlarged by identifying subtle geochemical variations related to ore-forming processes in the host rocks. This study examines the spatial variability of whole-rock concentrations of platinum group elements (PGEs) within the host flow to massive nickel sulfide mineralization at the Long-Victor deposit, Kambalda dome (Western Australia), where a series of ore shoots occupy two subparallel channels, over a strike length of approximately 3,000 m. The basal komatiite flow unit at Long-Victor contains a wide range of platinum group element concentrations and PGE/Ti ratios in S-poor rocks outside the ore shoots. About a third of the samples analyzed show evidence for either enrichment or depletion in PGEs, as estimated from mantle-normalized ratios of Pt/Ti, Pd/Ti, and Rh/Ti, relative to background values typical of those found in Neoarchean Munro-type komatiites worldwide. The very strong correlations observed between Pt/Ti, Pd/Ti, and Rh/Ti testify to a primary magmatic origin of this signal. Depletion signatures are largely restricted to samples in the flanking environment within the basal flow, and are found both in spinifex-textured A-zone and cumulate B-zone samples. The strongest depletion signatures are preserved in the uppermost portions of the A-zone and decrease in magnitude with increasing depth from the stratigraphic top of the spinifex horizon downward. This is interpreted as the result of progressive flushing of the flow channel by PGE-undepleted lava subsequent to ore formation. Enriched signatures are largely restricted to cumulate rock types, and are found within both channels and flanks. The halo of anomalous PGE/Ti ratios, both depleted and enriched, extends more than 400 m from the cutoff of 0.4% Ni that defines the limit of disseminated ores, and is much more extensive and marked than anomalies defined by Ni concentrations, Ni/Cr ratios, or Ni/Ti ratios, which extend no more than 20 m beyond the disseminated ores themselves. The PGE enrichment halo is recognizable in rocks having no visible sulfide and having Ni values falling within the silicate background, and is attributed to the accumulation of small proportions of PGE-rich disseminated sulfide liquid formed at high R factors, with subsequent loss of S during hydrothermal alteration. Mapping of PGE/Ti ratios provides an effective and sensitive method for vectoring toward ore during mine-scale and prospect-scale exploration, and is potentially applicable to mafic systems as well as to komatiites.
The Metal Content of Silicate Melts and Aqueous Fluids in Subeconomically Mo Mineralized Granites: Implications for Porphyry Mo Genesis
Authors: Lerchbaumer Linda , Audétat Andreas 
Published: June 2013

Abstract
To better understand the factors leading to porphyry Mo mineralization, we studied melt and fluid inclusions in three subeconomically Mo mineralized granites in well-known Mo provinces: the Treasure Mountain dome in the Colorado mineral belt (USA), and the Drammen and Glitrevann granites in the Oslo rift (Norway). Melt and fluid inclusions were investigated in samples ranging from coarsely crystallized whole rocks to euhedral quartz crystals within miarolitic cavities. The major and trace element chemistry of individual inclusions was determined by laser ablation-inductively coupled plasma-mass spectrometry. Melt inclusions are rhyolitic in composition and record a clear trend of increasing Mo concentrations with increasing degree of melt differentiation as monitored by Cs, extending from ~5 to 10 ppm Mo at 5 ppm Cs to ~17 to 40 ppm Mo at 100 ppm Cs. Coexisting magmatic fluids were single phase, had a salinity of 4 to 6 wt % NaCl equiv and a density of 0.6 to 0.7 g/cm3, and contained ~0.5 wt % S and up to 6 mol % CO2. Molybdenum concentrations in these fluids ranged from ~20 to ~200 ppm Mo, except for some highly evolved fluids that had lower Mo contents.
Comparison of our data with published fluid and melt inclusion data from porphyry Mo deposits, porphyry Cu (Mo, Au) deposits, and barren intrusions reveals that most subduction-related magmas have lower Mo/Cs ratios than within-plate magmas, but that within these two groups there are no systematic differences between barren and productive intrusions. This suggests that the mineralization potential was not primarily controlled by the metal content of the melts and fluids, but rather by other factors such as size of the magma chamber and the efficiency of residual melt and fluid extraction from the magma chamber and their focusing into a small apophysis at its top. Based on our data, it can be calculated that at least several tens of km3 of magma were necessary to form intermediate-sized Mo deposits, and at least several hundred km3 to form giant (≥1 Mt Mo) deposits. All three granites investigated in this study would have been large enough to produce at least an intermediate-sized Mo deposit, but they nevertheless are only subeconomically mineralized. Their low productivity thus appears to be the result of poor fluid focusing. Factors promoting a high degree of fluid focusing include (1) accumulation of major volumes of fractionated, crystal-poor melts at the top of the magma chamber, (2) formation of an apophysis, and (3) development of convection cells, leading to an efficient circulation of these fractionated melts through the apophysis.
Book-to-Market Ratio and Skewness of Stock Returns
Authors: Zhang Xiao-Jun 
Published: June 2013

ABSTRACT:
This study demonstrates that stocks with low book-to-market ratios, also known as glamour stocks, have significantly more positive skewness in their return distributions compared to the return distributions of value stocks with high book-to-market ratios. The premium (discount) investors apply to these glamour (value) stocks also correlates significantly with the difference in return skewness. These findings suggest that the value/glamour-stock puzzle is partially explained by investor preference for positive skewness in stock returns. Such preference for skewness, which is consistent with investors having inverse S-shaped utility functions, is observed in such consumer behaviors as lottery purchases and gambling. This paper further documents significant predictive power of accounting-based measures, such as the book rate of return, with respect to the skewness of stock returns.
Data Availability: Data are available from sources identified in the paper.
When are Enhanced Relationship Tax Compliance Programs Mutually Beneficial?
Authors: De Simone Lisa , Sansing Richard C. , Seidman Jeri K. 
Published: June 2013

ABSTRACT:
This study investigates the circumstances under which “enhanced relationship” tax-compliance programs are mutually beneficial to taxpayers and tax authorities, as well as how these benefits are shared. We develop a model of taxpayer and tax authority behavior inside and outside of an enhanced relationship program. Our model suggests that, despite the adversarial nature of the relationship, an enhanced relationship program is mutually beneficial in many settings. The benefits are due to lower combined government audit and taxpayer compliance costs. These costs are lower because taxpayers are less likely to claim positions with weak support and the government is less likely to challenge positions with strong support inside the program. Further, we show that an increase in the ability of the tax authority to identify uncertain tax positions makes an enhanced relationship tax-compliance program more attractive to both the taxpayer and the tax authority.
JEL Classifications: H26