bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shock wave synthesis of amino acids from solutions of ammonium formate and ammonium bicarbonate
Authors: Suzuki Chizuka , Furukawa Yoshihiro , Kobayashi Takamichi , Sekine Toshimori , Nakazawa Hiromoto , Kakegawa Takeshi 
Published: July 2015

AbstractThe emergence of life's building blocks, such as amino acids and nucleobases, on the prebiotic Earth was a critical step for the beginning of life. Reduced species with low mass, such as ammonia, amines, or carboxylic acids, are potential precursors for these building blocks of life. These precursors may have been provided to the prebiotic ocean by carbonaceous chondrites and chemical reactions related to meteorite impacts on the early Earth. The impact of extraterrestrial objects on Earth occurred more frequently during this period than at present. Such impacts generated shock waves in the ocean, which have the potential to progress chemical reactions to form the building blocks of life from reduced species. To simulate shock‐induced reactions in the prebiotic ocean, we conducted shock‐recovery experiments on ammonium bicarbonate solution and ammonium formate solution at impact velocities ranging from 0.51 to 0.92 km/s. In the products from the ammonium formate solution, several amino acids (glycine, alanine, ß‐alanine, and sarcosine) and aliphatic amines (methylamine, ethylamine, propylamine, and butylamine) were detected, although yields were less than 0.1 mol % of the formic acid reactant. From the ammonium bicarbonate solution, smaller amounts of glycine, methylamine, ethylamine, and propylamine were formed. The impact velocities used in this study represent minimum cases because natural meteorite impacts typically have higher velocities and longer durations. Our results therefore suggest that shock waves could have been involved in forming life's building blocks in the ocean of prebiotic Earth, and potentially in aquifers of other planets, satellites, and asteroids.
Effects of inherited cores and magmatic overgrowths on zircon (U‐Th)/He ages and age‐eU trends from Greater Himalayan sequence rocks, Mount Everest region, Tibet
Authors: Orme Devon A. , Reiners Peter W. , Hourigan Jeremy K. , Carrapa Barbara 
Published: July 2015

AbstractPrevious constraints on the timing and rate of exhumation of the footwall of the South Tibetan detachment system (STDS) north of Mount Everest suggest rapid Miocene cooling from ∼ 700°C to 120°C between ∼14–17 Ma. However, 25 new single grain zircon He ages from leucogranites intruding Greater Himalayan Sequence rocks in the footwall of the STDS are between 9.9 and 15 Ma, with weighted mean ages between 10 and 12 Ma. Zircon grains exhibit a positive correlation between age and effective uranium (eU). Laser ablation zircon U‐Pb geochronology, detailed SEM observations, and laser ablation depth‐profiling of these zircons reveal low‐eU 0.5–2.5 Ga inherited cores overgrown by high‐eU 17–22 Ma rims. This intragranular zonation produces ages as much as 32% too young when a standard alpha‐ejection correction assuming uniform eU distribution is applied. Modeling of the effects of varying rim thickness and rim eU concentration on the bulk grain eU and alpha‐ejection correction suggests that zonation also exerts the primary control on the form of the age‐eU correlation observed. Application of grain‐specific zonation‐dependent age corrections to our data yields zircon He ages between 14 and 17 Ma, in agreement with AFT and 40Ar/39Ar ages. Growth of magmatic rims followed by cooling to < 120°C within 1–6 million years supports rapid tectonic exhumation associated with slip along the STDS in the Miocene. This study highlights the importance of characterizing parent nuclide zonation in zircon He studies which seek to understand the timing of exhumation along exhumed crustal blocks.
Anomalously strong observations of PKiKP/PcP amplitude ratios on a global scale
Authors: Waszek Lauren , Deuss Arwen 
Published: July 2015

AbstractThe inner core boundary marks the phase transition between the solid inner core and the fluid outer core. As the site of inner core solidification, the boundary provides insight into the processes generating the seismic structures of the inner core. In particular, it may hold the key to understanding the previously observed hemispherical asymmetry in inner core seismic velocity, anisotropy, and attenuation. Here we use a large PKiKP‐PcP amplitude ratio and travel time residual data set to investigate velocity and density contrast properties near the inner core boundary. Although hemispherical structure at the boundary has been proposed by previous inner core studies, we find no evidence for hemispheres in the amplitude ratios or travel time residuals. In addition, we find that the amplitude ratios are much larger than can be explained by variations in density contrast at the inner core boundary or core‐mantle boundary. This indicates that PKiKP is primarily observed when it is anomalously large, due to focusing along its raypath. Using data in which PKiKP is not detected above the noise level, we calculate an upper estimate for the inner core boundary (ICB) density contrast of 1.2 kg m−3. The travel time residuals display large regional variations, which differ on long and short length scales. These regions may be explained by large‐scale velocity variations in the F layer just above the inner core boundary, and/or small‐scale topography of varying magnitude on the ICB, which also causes the large amplitudes. Such differences could arise from localized freezing and melting of the inner core.
Investigating flow properties of partially cemented fractures in Travis Peak Formation using image‐based pore‐scale modeling
Authors: Tokan‐Lawal Adenike , Prodanović Maša , Eichhubl Peter 
Published: July 2015

AbstractNatural fractures can provide preferred flow pathways in otherwise low‐permeability reservoirs. In deep subsurface reservoirs including tight oil and gas reservoirs, as well as in hydrothermal systems, fractures are frequently lined or completely filled with mineral cement that reduces or occludes fracture porosity and permeability. Fracture cement linings potentially reduce flow connectivity between the fracture and host rock and increase fracture wall roughness, which constricts flow. We combined image‐based fracture space characterization, mercury injection capillary pressure and permeability experiments, and numerical simulations to evaluate the influence of fracture‐lining cement on single‐phase and multiphase flows along a natural fracture from the Travis Peak Formation, a tight gas reservoir sandstone in East Texas. Using X‐ray computed microtomographic image analysis, we characterized fracture geometry and the connectivity and geometric tortuosity of the fracture pore space. Combining level set method‐based progressive quasistatic and lattice Boltzmann simulations, we assessed the capillary‐dominated displacement properties and the (relative) permeability of a cement‐lined fracture. Published empirical correlations between aperture and permeability for barren fractures provide permeability estimates that vary among each other, and differ from our results, vary by several orders of magnitude. Compared to barren fractures, cement increases the geometric tortuosity, aperture variation of the pore space, and capillary pressure while reducing the single‐phase permeability by up to 2 orders of magnitude. For multiphase displacement, relative permeability and fluid entrapment geometry resemble those of porous media and differ from those characteristic of barren fractures.
Seasonal advection of Pacific Equatorial Water alters oxygen and pH in the Southern California Bight
Authors: Nam SungHyun , Takeshita Yuichiro , Frieder Christina A. , Martz Todd , Ballard John 
Published: July 2015

AbstractChemical properties of the California Undercurrent (CU) have been changing over the past several decades, yet the mechanisms responsible for the trend are still not fully understood. We present a survey of temperature, salinity, O2, pH, and currents at intermediate depths (defined here as 50–500 m) in the summer (30 June to 10 July) and winter (8–15 December) of 2012 in the southern region of the Southern California Bight. Observations of temperature, salinity, and currents reveal that local bathymetry and small gyres play an important role in the flow path of the California Undercurrent (CU). Using spiciness (π) as a tracer, we observe a 10% increase of Pacific Equatorial Water (PEW) in the core of the CU during the summer versus the winter. This is associated with an increase in π of 0.2, and a decrease in O2 and pH of 30 μmol kg−1 and 0.022, respectively; the change in pH is driven by increased CO2, while total alkalinity remains unchanged. The high‐π, low‐O2, and low‐pH waters during the summer are not distributed uniformly in the study region. Moreover, mooring observations at the edge of the continental shelf reveal intermittent intrusions of PEW onto the shelf with concomitant decreases in O2 and pH. We estimate that increased advection of PEW in the CU could account for approximately 50% of the observed decrease in O2, and between 49 and 73% of the decrease in pH, over the past three decades.
Transport properties of silicate melts
Authors: Ni Huaiwei , Hui Hejiu , Steinle‐Neumann Gerd 
Published: July 2015

AbstractA quantitative description of the transport properties,diffusivity,viscosity,electrical, andthermal conductivity, of silicate melts is essential for understanding melting‐related petrologic and geodynamic processes. We here provide a systematic overview on the current knowledge of these properties from experiments and molecular dynamics simulations, their dependence on pressure, temperature, and composition, atomistic processes underlying them, and physical models to describe their variations. We further establish phenomenological and physical links between diffusivity, viscosity, and electrical conductivity that are based on structural rearrangement in the melt. Neutral molecules and network‐modifying cations with low electric field strength displayintrinsic diffusivity, which is controlled by the intrinsic properties (size and valence) of the species. By contrast, oxygen and network formers with high field strength showextrinsic diffusivity, which is more sensitive to extrinsic parameters including temperature (T), pressure (P), and melt composition (X). SimilarT‐P‐Xdependence of diffusivity and electrical conductivity and their quantitative relation reveal the role of intrinsically diffusing species in electrical transport, while viscosity is tied to the extrinsically diffusing species in a similar way. However, the differences in the structural role and mobility of various atomic species diminish with increasing temperature and/or pressure: all transport processes are increasingly coupled, eventually converging to a uniform rate and mechanism. Accurate comprehension of interatomic interactions and melt structure is vital to fully accounting for the compositional dependence of transport properties, and simple polymerization parameters such as nonbridging oxygen per tetrahedrally coordinated cation are inadequate.
The morphology of streams restored for market and nonmarket purposes: Insights from a mixed natural‐social science approach
Authors: Doyle Martin W. , Singh Jai , Lave Rebecca , Robertson Morgan M. 
Published: July 2015

AbstractWe use geomorphic surveys to quantify the differences between restored and nonrestored streams, and the difference between streams restored for market purposes (compensatory mitigation) from those restored for nonmarket programs. We also analyze the social and political‐economic drivers of the stream restoration and mitigation industry using analysis of policy documents and interviews with key personnel including regulators, mitigation bankers, stream designers, and scientists. Restored streams are typically wider and geomorphically more homogenous than nonrestored streams. Streams restored for the mitigation market are typically headwater streams and part of a large, complex of long restored main channels, and many restored tributaries; streams restored for nonmarket purposes are typically shorter and consist of the main channel only. Interviews reveal that designers integrate many influences including economic and regulatory constraints, but traditions of practice have a large influence as well. Thus, social forces shape the morphology of restored streams.
A Universal Approach to Ultrasmall Magneto‐Fluorescent Nanohybrids
Authors: Feld Artur , Merkl Jan‐Philip , Kloust Hauke , Flessau Sandra , Schmidtke Christian , Wolter Christopher , Ostermann Johannes , Kampferbeck Michael , Eggers Robin , Mews Alf , Schotten Theo , Weller Horst 
Published: July 2015

AbstractSeeded emulsion polymerization is a powerful universal method to produce ultrasmall multifunctional magnetic nanohybrids. In a two‐step procedure, iron oxide nanocrystals were initially encapsulated in a polystyrene (PS) shell and subsequently used as beads for a controlled assembly of elongated quantum dots/quantum rods (QDQRs). The synthesis of a continuous PS shell allows the whole construct to be fixed and the composition of the nanohybrid to be tuned. The fluorescence of the QDQRs and magnetism of iron oxide were perfectly preserved, as confirmed by single‐particle investigation, fluorescence decay measurements, and relaxometry. Bio‐functionalization of the hybrids was straightforward, involving copolymerization of appropriate affinity ligands as shown by immunoblot analysis. Additionally, the universality of this method was shown by the embedment of a broad scale of NPs.
Ruthenium‐Catalyzed Monoalkenylation of Aromatic Ketones by Cleavage of Carbon–Heteroatom Bonds with Unconventional Chemoselectivity
Authors: Kondo Hikaru , Akiba Nana , Kochi Takuya , Kakiuchi Fumitoshi 
Published: July 2015

AbstractRuthenium‐catalyzed selective monoalkenylation of ortho CO or CN bonds of aromatic ketones was achieved. The reaction allowed the direct comparison of the relative reactivities of the cleavage of different carbon‐heteroatom bonds, thus suggesting an unconventional chemoselectivity, where smaller, more‐electron‐donating groups are more easily cleaved. Selective monofunctionalization of CO bonds in the presence of ortho CH bonds was also achieved.
The Efficacy and Safety of Subcutaneous Clazakizumab in Patients With Moderate‐to‐Severe Rheumatoid Arthritis and an Inadequate Response to Methotrexate: Results From a Multinational, Phase IIb, Randomized, Double‐Blind, Placebo/Active‐Controlled, Dose‐Ranging Study
Authors: Weinblatt Michael E. , Mease Philip , Mysler Eduardo , Takeuchi Tsutomu , Drescher Edit , Berman Alberto , Xing Jun , Zilberstein Moshe , Banerjee Subhashis , Emery Paul 
Published: July 2015

ObjectiveClazakizumab is a humanized monoclonal antibody that binds to the interleukin‐6 (IL‐6) cytokine. This study was undertaken to evaluate the efficacy and safety of clazakizumab in combination with methotrexate (MTX) or clazakizumab monotherapy versus MTX alone in patients with rheumatoid arthritis (RA) and an inadequate response to MTX.MethodsIn this multinational, phase IIb, randomized, double‐blind, placebo‐controlled, dose‐ranging study, patients were randomized to receive 1) once‐monthly subcutaneous (SC) clazakizumab at 25, 100, or 200 mg plus MTX, 2) once‐monthly SC clazakizumab at 100 mg or 200 mg as monotherapy, or 3) MTX plus placebo (i.e., MTX alone). Adalimumab (40 mg) plus MTX was included as an active reference. The primary end point was the American College of Rheumatology 20% (ACR20) improvement response rate at week 12. Secondary end points included ACR20, ACR50, and ACR70 response rates as well as protocol‐defined remission rates and Health Assessment Questionnaire disability index scores at weeks 12 and 24.ResultsIn total, 418 patients were randomized, and baseline characteristics were balanced across the treatment groups. Patients receving clazakizumab had significantly greater ACR20 response rates at week 12 compared with patients receiving MTX alone (76.3%, 73.3%, and 60.0% of patients in the clazakizumab 25, 100, and 200 mg plus MTX groups, respectively, and 55.0% and 61.0% of patients in the clazakizumab 100 and 200 mg monotherapy groups, respectively, versus 39.3% of patients receiving MTX alone; P < 0.05 for all comparisons). At week 24, all clazakizumab groups had higher ACR20, ACR50, and ACR70 response rates and higher remission rates compared with MTX alone. Rates of serious adverse events ranged from 8.3% to 13.6% in the clazakizumab treatment groups, compared with 3.3% in the MTX alone group. Changes in laboratory data were consistent with the pharmacologic effects of IL‐6 blockade.ConclusionIn patients with RA and an inadequate response to MTX, treatment with clazakizumab in combination with MTX or clazakizumab monotherapy was well tolerated, and patients achieved significant improvements in disease activity, including higher rates of remission, as compared with patients receiving MTX alone.
Role of the Neutrophil Chemorepellent Soluble Dipeptidyl Peptidase IV in Decreasing Inflammation in a Murine Model of Arthritis
Authors: Herlihy Sarah E. , Brown Monica L. , Pilling Darrell , Weeks Brad R. , Myers Linda K. , Gomer Richard H. 
Published: July 2015

ObjectiveTo determine whether an intraarticular injection of the neutrophil chemorepellent dipeptidyl peptidase IV (DPPIV; CD26) can attenuate inflammation and decrease the severity of arthritis in a murine model.MethodsDBA/1 mice were immunized with type II collagen/Freund's complete adjuvant to produce collagen‐induced arthritis (CIA). On day 25 postimmunization, recombinant human DPPIV (rhDPPIV) or phosphate buffered saline was injected intraarticularly, and arthritis severity scores were recorded 3 times per week. The hind legs of mice in both groups were fixed, decalcified, paraffin embedded, and sectioned. Pathologic scores for inflammation and neutrophil infiltration were recorded on a scale of 1–8, and the number of neutrophils was determined by morphometric cell counts. In addition, Mac‐2–positive macrophages and articular damage were assessed using anti–Mac‐2 antibodies and histologic staining, respectively.ResultsInjection of rhDPPIV reduced the mean score of arthritis severity in mice with CIA. DPPIV treatment reduced the overall extent of inflammation and articular damage around the arthritic joint and periarticular tissue, and also decreased neutrophil and macrophage infiltration.ConclusionA localized injection of the neutrophil chemorepellent DPPIV reduces inflammation and the severity of the disease in a murine model of arthritis.
Protein Tyrosine Phosphatase Nonreceptor Type 2: An Important Regulator of lnterleukin‐6 Production in Rheumatoid Arthritis Synovial Fibroblasts
Authors: Aradi Borbala , Kato Masaru , Filkova Maria , Karouzakis Emmanuel , Klein Kerstin , Scharl Michael , Kolling Christoph , Michel Beat A. , Gay Renate E. , Buzas Edit I. , Gay Steffen , Jüngel Astrid 
Published: July 2015

ObjectiveTo investigate the role of protein tyrosine phosphatase nonreceptor type 2 (PTPN2) in the pathogenesis of rheumatoid arthritis (RA).MethodsSynovial tissue samples from patients with RA and patients with osteoarthritis (OA) were stained for PTPN2. Synovial fibroblasts were stimulated with tumor necrosis factor (TNF) and interleukin‐1β (IL‐1β), lipopolysaccharide (LPS), TRAIL, or thapsigargin. The expression of PTPN2 in synovial fibroblasts and peripheral blood mononuclear cells (PBMCs) was analyzed by real‐time polymerase chain reaction and Western blotting. Cell death, the release of IL‐6 and IL‐8, and the induction of autophagy were analyzed after PTPN2 silencing. Methylated DNA immunoprecipitation analysis was used to evaluate DNA methylation–regulated gene expression of PTPN2.ResultsPTPN2 was significantly overexpressed in synovial tissue samples from RA patients compared to OA patients. Patients receiving anti‐TNF therapy showed significantly reduced staining for PTPN2 compared with patients treated with nonbiologic agents. PTPN2 expression was higher in RA synovial fibroblasts (RASFs) than in OASFs. This differential expression was not regulated by DNA methylation. PTPN2 was further up‐regulated after stimulation with TNF, TNF combined with IL‐1β, or LPS. There was no significant difference in basal PTPN2 expression in PBMCs from patients with RA, ankylosing spondylitis, or systemic lupus erythematosus or healthy controls. Most interestingly, PTPN2 silencing in RASFs significantly increased the production of the inflammatory cytokine IL‐6 but did not affect levels of IL‐8. Moreover, functional analysis showed that high PTPN2 levels contributed to the increased apoptosis resistance of RASFs and increased autophagy.ConclusionThis is the first study of PTPN2 in RASFs showing that PTPN2 regulates IL‐6 production, cell death, and autophagy. Our findings indicate that PTPN2 is linked to the pathogenesis of RA via synovial fibroblasts.
Brief Report: Enrichment of Activated Group 3 Innate Lymphoid Cells in Psoriatic Arthritis Synovial Fluid
Authors: Leijten Emmerik F. A. , van Kempen Tessa S. , Boes Marianne , Michels‐van Amelsfort Jocea M. R. , Hijnen Dirkjan , Hartgring Sarita A. Y. , van Roon Joel A. G. , Wenink Mark H. , Radstake Timothy R. D. J. 
Published: July 2015

ObjectiveInnate lymphoid cells (ILCs) are a recently discovered group of cells that are essential to epithelial homeostasis and are implicated in psoriasis pathogenesis, yet they have never been reported in psoriatic arthritis (PsA).MethodsILC classes and subsets were characterized in the peripheral blood (PB) of healthy controls, patients with psoriasis, and patients with PsA and in the synovial fluid (SF) of patients with PsA and patients with rheumatoid arthritis (RA). Cell surface marker expression and intracellular cytokine production following stimulation were analyzed using flow cytometry.ResultsILCs were identified in the SF and were 4‐fold more abundant in PsA SF than in PsA PB. Fewer CCR6+ ILCs were found in PsA PB than in healthy control PB, while PsA SF was enriched for CCR6+ ILCs compared to PsA PB and RA SF. Natural cytotoxicity receptor NKp44+ group 3 ILCs were rare in PB and RA SF, but abundant in PsA SF. Increased numbers of interleukin‐17A (IL‐17A)–producing ILCs were present in PsA SF compared to RA SF. CCR6, NKp44, and melanoma cell adhesion molecule (MCAM) were expressed on the cell surface of SF ILCs that produced IL‐17A. The number of circulating NKp44+, CCR6+, and MCAM+ ILCs in blood was inversely correlated with PsA disease activity.ConclusionOur findings indicate that PsA SF is enriched for group 3 ILCs that express CCR6 and NKp44, which distinguishes the synovial compartment from RA. The increased IL‐17A production by SF ILCs indicates a novel role for ILCs in PsA.