bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
Authors: Wild Birgit , Schnecker Jörg , Knoltsch Anna , Takriti Mounir , Mooshammer Maria , Gentsch Norman , Mikutta Robert , Alves Ricardo J. Eloy , Gittel Antje , Lashchinskiy Nikolay , Richter Andreas 
Published: April 2015

AbstractSoil N availability is constrained by the breakdown of N‐containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrification. According to stoichiometric theory, N mineralization and nitrification are expected to increase in relation to protein depolymerization with decreasing N limitation, and thus from higher to lower latitudes and from topsoils to subsoils. To test these hypotheses, we compared gross rates of protein depolymerization, N mineralization and nitrification (determined using 15N pool dilution assays) in organic topsoil, mineral topsoil, and mineral subsoil of seven ecosystems along a latitudinal transect in western Siberia, from tundra (67°N) to steppe (54°N). The investigated ecosystems differed strongly in N transformation rates, with highest protein depolymerization and N mineralization rates in middle and southern taiga. All N transformation rates decreased with soil depth following the decrease in organic matter content. Related to protein depolymerization, N mineralization and nitrification were significantly higher in mineral than in organic horizons, supporting a decrease in microbial N limitation with depth. In contrast, we did not find indications for a decrease in microbial N limitation from arctic to temperate ecosystems along the transect. Our findings thus challenge the perception of ubiquitous N limitation at high latitudes, but suggest a transition from N to C limitation of microorganisms with soil depth, even in high‐latitude systems such as tundra and boreal forest.
Estimates of future warming‐induced methane emissions from hydrate offshore west Svalbard for a range of climate models
Authors: Marín‐Moreno Héctor , Minshull Timothy A. , Westbrook Graham K. , Sinha Bablu 
Published: April 2015

AbstractMethane hydrate close to the hydrate stability limit in seafloor sediment could represent an important source of methane to the oceans and atmosphere as the oceans warm. We investigate the extent to which patterns of past and future ocean‐temperature fluctuations influence hydrate stability in a region offshore West Svalbard where active gas venting has been observed. We model the transient behavior of the gas hydrate stability zone at 400–500 m water depth (mwd) in response to past temperature changes inferred from historical measurements and proxy data and we model future changes predicted by seven climate models and two climate‐forcing scenarios (Representative Concentration Pathways RCPs 2.6 and 8.5). We show that over the past 2000 year, a combination of annual and decadal temperature fluctuations could have triggered multiple hydrate‐sourced methane emissions from seabed shallower than 400 mwd during episodes when the multidecadal average temperature was similar to that over the last century (∼2.6°C). These temperature fluctuations can explain current methane emissions at 400 mwd, but decades to centuries of ocean warming are required to generate emissions in water deeper than 420 m. In the venting area, future methane emissions are relatively insensitive to the choice of climate model and RCP scenario until 2050 year, but are more sensitive to the RCP scenario after 2050 year. By 2100 CE, we estimate an ocean uptake of 97–1050 TgC from marine Arctic hydrate‐sourced methane emissions, which is 0.06–0.67% of the ocean uptake from anthropogenic CO2 emissions for the period 1750–2011.
Determining the source characteristics of explosions near the Earth's surface
Authors: Pasyanos Michael E. , Ford Sean R. 
Published: April 2015

AbstractWe present a method to determine source characteristics of explosions near the Earth's surface. The technique accounts for the reduction in amplitudes as the explosion depth approaches the free surface and less energy is coupled into the ground. We apply the method to the Humming Roadrunner series of shallow explosions in New Mexico where the yields and depths are known. Knowledge of the material properties is needed for both source coupling/excitation and the free surface effect. Although there is the expected trade‐off between depth and yield, the estimated yields are close to the known values when the depth is constrained to the free surface. We then apply the method to a regionally recorded explosion in Syria. We estimate an explosive yield less than the 60 t claimed by sources in the open press. The modifications to the method allow us to apply the technique to new classes of events.
Thrust‐type focal mechanisms of tectonic tremors in Taiwan: Evidence of subduction
Authors: Ide Satoshi , Yabe Suguru , Tai Hsin‐Ju , Chen Kate Huihsuan 
Published: April 2015

AbstractUnlike tectonic tremors in subduction zones and along transform faults, the hosting structure for tremors in Taiwan remains debated. Tectonic tremors in Taiwan have been discovered at ~30 km depth beneath the southern Central Range, which is a young and active collisional mountain belt. Here we provide the first evidence for the focal mechanism of tremor using moment tensor inversion in the very low frequency band, employing broadband seismograms stacked relative to the hypocentral time of tremor. The best solution corresponds to low‐angle thrust faulting, suggesting the subduction of the Eurasian plate. This mechanism is consistent with strong tidal modulation of tremor activity but differs from the normal‐type faulting that dominates regional shallow earthquakes. This result suggests vertical variations in the tectonic stress regime. Thrust faulting may be facilitated by a decrease in normal stress due to the buoyant roots of the mountain belt and local high fluid pressure.
Self‐consistent multifluid MHD simulations of Europa's exospheric interaction with Jupiter's magnetosphere
Authors: Rubin M. , Jia X. , Altwegg K. , Combi M. R. , Daldorff L. K. S. , Gombosi T. I. , Khurana K. , Kivelson M. G. , Tenishev V. M. , Tóth G. , van der Holst B. , Wurz P. 
Published: April 2015

AbstractThe Jovian moon, Europa, hosts a thin neutral gas atmosphere, which is tightly coupled to Jupiter's magnetosphere. Magnetospheric ions impacting the surface sputter off neutral atoms, which, upon ionization, carry currents that modify the magnetic field around the moon. The magnetic field in the plasma is also affected by Europa's induced magnetic field. In this paper we investigate the environment of Europa using our multifluid MHD model and focus on the effects introduced by both the magnetospheric and the pickup ion populations. The model self‐consistently derives the electron temperature that governs the electron impact ionization process, which is the major source of ionization in this environment. The resulting magnetic field is compared to measurements performed by the Galileo magnetometer, the bulk properties of the modeled thermal plasma population is compared to the Galileo Plasma Subsystem observations, and the modeled surface precipitation fluxes are compared to Galileo Ultraviolet Spectrometer observations. The model shows good agreement with the measured magnetic field and reproduces the basic features of the plasma interaction observed at the moon for both the E4 and the E26 flybys of the Galileo spacecraft. The simulation also produces perturbations asymmetric about the flow direction that account for observed asymmetries.
Surface roughness and breaking wave properties retrieved from polarimetric microwave radar backscattering
Authors: Hwang Paul A. , Fois Franco 
Published: April 2015

AbstractOcean surface roughness and wave breaking are the two main contributors of radar backscattering from the ocean surface. The relative weightings of the two contributions vary with the microwave polarization: the VV (vertical transmit vertical receive) is dominated by the Bragg resonance scattering mechanism, and the HH (horizontal transmit horizontal receive) and VH (horizontal transmit vertical receive or vertical transmit horizontal receive) contain nontrivial non‐Bragg contributions mainly produced by breaking features. A method is developed to obtain the short‐scale properties of ocean surface roughness and wave breaking from Ku, C, and L band polarimetric sea returns. The results are used for quantitative evaluation of the ocean surface roughness spectral models and for deriving understanding of the breaking contribution important to microwave ocean remote sensing, in particular its dependence on wind speed, microwave frequency, and incidence angle. Implications of the results to air‐sea interaction applications are discussed.
A Catalyst‐Free Approach to Construct 3‐(Cyclopentenone)oxindoles Through a Phosphine‐Ylide‐Initiated Triple Domino Sequence
Authors: Du Yanlong , Liu Yufen , Yu Aimin , Qin Dabin , Zhang Kui , Meng Xiangtai 
Published: April 2015

AbstractA catalyst‐free domino reaction was developed for the synthesis of 3‐(cyclopentenone)oxindoles. This method is the first example of a phosphine‐ylide‐initiated Wittig/Michael addition/Wittig domino sequence. The mild reaction conditions and broad functional groups tolerance make it highly valuable for synthesizing 3‐(cyclopentenone)oxindoles.
Influence of process parameters on sorption capacity of microwave activated biosorbents for urea recovery from human urine: a comparative study
Authors: Ganesapillai M. , Venugopal A. , Ananthkrishna V. , Tapankrishna N. 
Published: April 2015

AbstractThe present investigation elicits a comparative study for recovering urea from human urea via adsorption onto three biosorbents: Microwave Activated Carbonized Bamboo Shoots (MACBS), Walnut Shells (MACWS) and Coconut Shells (MACCS). The rate of sorption was investigated under different process parameters including initial sorbate concentration, amount of sorbent, temperature and agitation speed, and further, sorption capacity of MACBS, MACWS and MACCS was compared. Batch results indicated that urea uptake capacity increased with an increase in sorbate concentration and a decrease in sorbent loading and temperature. The experimental data were tested against the Langmuir, Freundlich, Tempkin, Flory–Huggins and Dubinin–Radushkevich (D‐R) isotherms with the D‐R model being a good fit for MACBS and MACCS and the Freundlich model for MACWS. Kinetic studies were performed to understand the order and rate of the sorption process. While pseudo‐second‐order kinetic model fits best for MACBS and MACWS, pseudo‐first order was followed by MACCS. Based on the urea sorption capacity, the following order of suitability of precursors for activated carbon preparation was established: MACBS > MACCS > MACWS. This study illustrates the suitability of biomass‐based precursors for activated carbon preparation and nutrient recovery from wastewater streams like human urine for subsequent use as fertilizers on agricultural land. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Semiconducting polyurethane/polypyrrole/polyaniline for microorganism immobilization and wastewater treatment in anaerobic/aerobic sequential packed bed reactors
Authors: Antonio‐Carmona Iveth D. , Martínez‐Amador Silvia Y. , Martínez‐Gutiérrez Hugo , Ovando‐Medina Víctor M. , González‐Ortega Omar 
Published: April 2015

ABSTRACTThe development of new materials for microorganism immobilization is very important in wastewater treatment. In this work polyurethane (PU) foams were modified polymerizing pyrrole and aniline onto their surface by chemical oxidization to obtain polyurethane/polypyrrole (PU/PPy), polyurethane/polyaniline (PU/PANI), and PU/(PPy‐co‐PANI) supports which were used to immobilize microorganisms for municipal wastewater treatment in batch mode and continuous flow using two sequential (anaerobic/aerobic) packed bed reactors (PBR) varying the total hydraulic retention time (HRT). The supports were characterized by Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) and tested in chemical oxygen demand (COD) removal during treatment of a municipal wastewater. It was observed from SEM analysis that globular nanostructures of PPy and PPy‐co‐PANI were formed onto the PU surface with average diameters between 100 and 300 nm, which are typical of aqueous polymerization of pyrrole monomer; however irregular nanostructures were observed when PANI was homopolymerized onto the PU foam. Batch wastewater treatment after 14 days showed COD removal efficiencies of 77%, 69%, 78%, and 80% for PU foam, PU/PPy, PU/PANI, and PU/(PPy‐co‐PANI), respectively; which was explained as a function of polymers morphology deposited onto the PU foam surface. Also it was observed from the sequential PBR that for 24 h and 36 h of HRT, 80 and 90% of COD removal can be achieved; respectively.© 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42242.
Preparation and properties of polycarbonate nanocomposites using attapulgite grafted poly(methyl methacrylate) as a potential nanofiller
Authors: Xu Hang , Yang Haicun , Zhang Liu , Ni Qingting , Gong Fanghong 
Published: April 2015

ABSTRACTThe Core‐shell hybrid particles with attapulgite (ATP) as the core and polymethylmethacrylate (PMMA) as the shell (ATP‐g‐PMMA) were prepared via reversible addition‐fragmentation chain transfer (RAFT) polymerization method. The diameter of ATP‐g‐PMMA was increased to 50–60 nm, and the surface hygroscopicity was decreased observably after surface grafting. Then, ATP‐g‐PMMA hybrid particles were filled into the polycarbonate (PC) by melt mixing to afford nanocomposites, and the mechanical properties, microstructures, thermal stability, and rheological behavior of nanocomposites were investigated by varying ATP‐g‐PMMA concentration in the range 1, 3, 5, and 7 wt % in PC. Fourier Transform infrared spectroscopy (FTIR) suggested that there is no esterification reaction between particles and matrix. Slight changes in tensile strength, and noticeable decrease of elongation and impact strength were observed with the increase in ATP‐g‐PMMA particles loading. The morphology evaluated by field‐emission scanning electron microscopy (FESEM) indicated that ATP‐g‐PMMA was dispersed with a diameter range of 80–100 nm, and phase separation was appeared with increasing ATP‐g‐PMMA loadings. Thermogravimetric analysis (TGA) results revealed the thermal stability of composites was strengthened. The disentanglement and interface slip induced by preferred orientation and directional arrangement of ATP‐g‐PMMA resulted in lower complex viscosity (η*) and higher loss factor (tan δ) compared with the pristine PC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42262.
One‐pot Sequential Reactions Featuring a Copper‐catalyzed Amination Leading to Pyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines and Dihydropyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines
Authors: Fan Xue‐Sen , Zhang Ju , Li Bin , Zhang Xin‐Ying 
Published: April 2015

AbstractTetracyclic skeletons combining an imidazo[1,2‐a]pyridine moiety with a quinoline framework such as pyrido[2′,1′:2,3]imidazo[4,5‐b]quinoline are stimulating increasing interests since they are close isosteres of a series of powerful antiproliferative compounds. In this paper, we report a novel methodology for the synthesis of pyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines through one‐pot sequential reactions of commercially available or readily obtainable 2‐aminopyridines, 2‐bromophenacyl bromides, aqueous ammonia, and aldehydes. Moreover, dihydropyrido[2′,1′:2,3]imidazo[4,5‐c]quinolines could also be obtained in a similar manner by using various ketones as the substrates in place of aldehydes. Notably, the whole procedure combines condensation/amination/cyclization reactions in one pot to give complex compounds in a simple and practical manner. Compared with literature methods, the synthetic strategy reported herein has the advantages of readily available starting materials, structural diversity of products, good functional group tolerance, and obviation of step‐by‐step operations.
Highly Chemoselective and Versatile Method for Direct Conversion of Carboxylic Acids to Ketones Utilizing Zinc Ate Complexes
Authors: Murata Ryo , Hirano Keiichi , Uchiyama Masanobu 
Published: April 2015

AbstractVarious carboxylic acids were directly transformed into the corresponding ketones by utilizing organozinc ate complexes, which provide high chemoselectivity without any overreaction to the undesired tertiary carbinol, owing to formation of a stable tetrahedral zincioketal intermediate. This method offers good overall atom/step/pot economy and operational simplicity.
Highly sensitive fluorescence detection of glycoprotein based on energy transfer between CuInS2 QDs and rhodamine B
Authors: Gao Xue , Li Dan , Tong Ying , Ge Dan , Tang Yiwei , Zhang Defu , Li Jianrong 
Published: April 2015

AbstractA highly sensitive fluorescence method for glycoprotein detection has been established based on fluorescence resonance energy transfer (FRET) between CuInS2 quantum dots (QDs) and rhodamine B (RB). Lectins comprise a group of proteins with unique affinities toward carbohydrate structures, so the process of FRET can occur between lectin‐coated QDs (CuInS2 QDs–Con A conjugates, acceptors) and carbohydrate‐coated RB (RB–NH2‐glu conjugates, donors). The fluorescence of lectin‐coated QDs was recovered in the presence of a glycoprotein such as glucose oxidase (GOx) and transferrin (TRF), which significantly reduced the FRET efficiency between the donor and the acceptor. Under optimal conditions, a linear correlation was established between the fluorescence intensity ratio I654/I577 and the TRF concentration over the range of 6.90 × 10‐10 to 3.45 × 10‐8 mol/L, with a detection limit of 2.5 × 10‐10 mol/L. The linear range for GOx is 3.35 × 10‐10 to 6.70 × 10‐8 mol/L, with a detection limit of 1.5 × 10‐10 mol/L. The proposed method was applied to the determination of glycoprotein in human serum and cell‐extract samples with satisfactory results. Furthermore, CuInS2 QDs–Con A conjugates are used as safe and efficient optical nanoprobes in HepG2 cell imaging. Copyright © 2015 John Wiley & Sons, Ltd.
Development of protein mimics for intracellular delivery
Authors: deRonde Brittany M. , Tew Gregory N. 
Published: April 2015

ABSTRACTDesigning delivery agents for therapeutics is an ongoing challenge. As treatments and desired cargoes become more complex, the need for improved delivery vehicles becomes critical. Excellent delivery vehicles must ensure the stability of the cargo, maintain the cargo's solubility, and promote efficient delivery and release. In order to address these issues, many research groups have looked to nature for design inspiration. Proteins, such as HIV‐1 trans‐activator of transcription (TAT) and Antennapedia homeodomain protein, are capable of crossing cellular membranes. However, due to the complexities of their structures, they are synthetically challenging to reproduce in the laboratory setting. Being able to incorporate the key features of these proteins that enable cell entry into simpler scaffolds opens up a wide range of opportunities for the development of new delivery reagents with improved performance. This review charts the development of protein mimics based on cell‐penetrating peptides (CPPs) and how structure‐activity relationships (SARs) with these molecules and their protein counterparts ultimately led to the use of polymeric scaffolds. These scaffolds deviate from the normal peptide backbone, allowing for simpler, synthetic procedures to make carriers and tune chemical compositions for application specific needs. Successful design of polymeric protein mimics would allow researchers to further understand the key features in proteins and peptides necessary for efficient delivery and to design the next generation of more efficient delivery reagents. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 104: 265–280, 2015.
Kartogenin, transforming growth factor‐β1 and bone morphogenetic protein‐7 coordinately enhance lubricin accumulation in bone‐derived mesenchymal stem cells
Authors: Liu Chun , Ma Xueqin , Li Tao , Zhang Qiqing 
Published: April 2015

AbstractOsteoarthritis, a common joint degeneration, can cause breakdown of articular cartilage with the presence of lubricin metabolic abnormalities. Lubricin is a multi‐level chondroprotective mucinous glycoprotein in articular joints. Joint defect and infection is elevated and accompanied by accelerated cartilage lesions involving degradation and loss of lubricin. However, a novel, heterocyclic compound called kartogenin (KGN) was discovered to stimulate chondrogenic differentiation of bone‐derived mesenchymal stem cells (BMSCs). And the synergistic effect of transforming growth factor‐β1 (TGF‐β1) and bone morphogenetic protein‐7 (BMP‐7) could provoke lubricin accumulation. This paper attempted to explore the connection between accumulation of lubricin and the effect of TGF‐β1, BMP‐7 and/or KGN. Hence, we investigated the expression and secretion of lubricin in BMSCs treated with different combinations of TGF‐β1, BMP‐7, and/or KGN. Using an in vitro BMSCs system, we observed the content of lubricin from BMSCs treated with TGF‐β1, BMP‐7, and KGN was the highest at both the protein level and the gene level. The accumulation of lubricin was enhanced coordinately by the increase of synthesis and decrease of degradation possibly via c‐Myc and adamts5 pathway. These results further suggested that supplementation of the defect parts with lubricin by using growth factors and small molecules showed a promising potential on preventing joint deterioration in patients with acquired or genetic deficiency of lubricin in the future of regenerative medicine.
Palmitate exerts opposite effects on proliferation and differentiation of skeletal myoblasts
Authors: Grabiec Kamil , Milewska Marta , Błaszczyk Maciej , Gajewska Małgorzata , Grzelkowska‐Kowalczyk Katarzyna 
Published: April 2015

AbstractThe purpose of the study was to examine mechanisms controlling cell cycle progression/arrest and differentiation of mouse C2C12 myoblasts exposed to long‐chain saturated fatty acid salt, palmitate. Treatment of proliferating myoblasts with palmitate (0.1 mmol/l) markedly decreased myoblast number. Cyclin A and cyclin D1 levels decreased, whereas total p21 and p21 complexed with cyclin‐dependent kinase‐4 (cdk4) increased in myoblasts treated with palmitate. In cells induced to differentiation addition of palmitate augmented the level of cyclin D3, the early (myogenin) and late (α‐actinin, myosin heavy chain) markers of myogenesis, and caused an increase of myotube diameter. In conclusion, exposure to palmitate inhibits proliferation of myoblasts through a decrease in cyclin A and cyclin D1 levels and an increase of p21‐cdk4 complex formation; however, it promotes cell cycle exit, myogenic differentiation and myotube growth.
Moschusduft und Patchouliöl
Authors: Frister Thore , Beutel Sascha 
Published: April 2015

AbstractMoschus und Patchouliöl spielen in der Herstellung von Parfüms, diversen Kosmetik‐ und Haushaltsprodukten eine wichtige Rolle: Es gibt kaum ein Parfüm das ohne Patchouli‐ oder Moschusduft auskommt. Während Patchouliöl bis heute überwiegend aus pflanzlichen Quellen gewonnen wird, sind die verwendeten Moschusduftstoffe schon längst nicht mehr natürlichen Ursprungs. Dank der modernen Synthesechemie existieren für Moschus zahlreiche synthetische Ersatzstoffe. Der Trend zu mehr nachhaltig produzierten Kosmetikprodukten, stellt die konventionellen Produktionsprozesse vor Herausforderungen. Die Biotechnologie steht daher schon in den Startlöchern, um Duft‐ und Aromastoffe in Zukunft wirtschaftlich, umweltfreundlich und qualitativ hochwertig, produzieren zu können.