bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian pollution
Authors: Vernier J.‐P. , Fairlie T. D. , Natarajan M. , Wienhold F. G. , Bian J. , Martinsson B. G. , Crumeyrolle S. , Thomason L. W. , Bedka K. M. 
Published: January 2015

AbstractSatellite observations have shown that the Asian Summer Monsoon strongly influences the upper troposphere and lower stratosphere (UTLS) aerosol morphology through its role in the formation of the Asian Tropopause Aerosol Layer (ATAL). Stratospheric Aerosol and Gas Experiment II solar occultation and Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar observations show that summertime UTLS Aerosol Optical Depth (AOD) between 13 and 18 km over Asia has increased by three times since the late 1990s. Here we present the first in situ balloon measurements of aerosol backscatter in the UTLS from Western China, which confirm high aerosol levels observed by CALIPSO since 2006. Aircraft in situ measurements suggest that aerosols at lower altitudes of the ATAL are largely composed of carbonaceous and sulfate materials (carbon/sulfur elemental ratio ranging from 2 to 10). Back trajectory analysis from Cloud‐Aerosol Lidar with Orthogonal Polarization observations indicates that deep convection over the Indian subcontinent supplies the ATAL through the transport of pollution into the UTLS. Time series of deep convection occurrence, carbon monoxide, aerosol, temperature, and relative humidity suggest that secondary aerosol formation and growth in a cold, moist convective environment could play an important role in the formation of ATAL. Finally, radiative calculations show that the ATAL layer has exerted a short‐term regional forcing at the top of the atmosphere of −0.1 W/m2 in the past 18 years.
Predictability of dune activity in real dune fields under unidirectional wind regimes
Authors: Barchyn Thomas E. , Hugenholtz Chris H. 
Published: January 2015

AbstractWe present an analysis of 10 dune fields to test a model‐derived hypothesis of dune field activity. The hypothesis suggests that a quantifiable threshold exists for stabilization in unidirectional wind regimes: active dunes have slipface deposition rates that exceed the vegetation deposition tolerance, and stabilizing dunes have the opposite. We quantified aeolian sand flux, slipface geometry, and vegetation deposition tolerance to directly test the hypothesis at four dune fields (Bigstick, White Sands Stable, White Sands Active, and Cape Cod). We indirectly tested the hypothesis at six additional dune fields with limited vegetation data (Hanford, Año Nuevo, Skagen Odde, Salton Sea, Oceano Stable, and Oceano Active, “inverse calculation sites”). We used digital topographic data and estimates of aeolian sand flux to approximate the slipface deposition rates prior to stabilization. Results revealed a distinct, quantifiable, and consistent pattern despite diverse environmental conditions: the modal peak of prestabilization slipface deposition rates was 80% of the vegetation deposition tolerance at stabilized or stabilizing dune fields. Results from inverse calculation sites indicate deposition rates at stabilized sites were near a hypothesized maximum vegetation deposition tolerance (1 m a−1), and active sites had slipface deposition rates much higher. Overall, these results confirm the hypothesis and provide evidence of a globally applicable, simple, and previously unidentified predictor for the dynamics of vegetation cover in dune fields under unidirectional wind regimes.
Generation of hydrothermal Fe‐Si oxyhydroxide deposit on the Southwest Indian Ridge and its implication for the origin of ancient banded iron formations
Authors: Sun Zhilei , Li Jun , Huang Wei , Dong Hailiang , Little Crispin T. S. , Li Jiwei 
Published: January 2015

AbstractModern hydrothermal Fe‐Si oxyhydroxide deposits are now known to be analogues to ancient siliceous iron formations. In this study, samples of Fe‐Si oxyhydroxide deposits were collected from hydrothermal field on the Southwest Indian Ridge. An investigation of mineralization in these deposits was carried out based on a series of mineralogical and morphological methods. X‐ray diffraction and selected area electron diffraction analysis show that amorphous opal and poorly crystalline ferrihydrite are the major minerals. Furthermore, some typical filament structures detected by scanning electronic microscopy examinations, probably indicating the presence of Fe‐oxidizing bacteria (FeOB), are pervasive with the main constituents being Fe, Si, P, and C. We thus believe that chemolithoautotrophic FeOB play a significant role in the formation of Fe oxyhydroxide which can effectively oxidize reduced Fe(II) sourced from hydrothermal fluids. Precipitation of amorphous silica, in contrast, is only a passive process with the Fe oxyhydroxide acting as a template. The distinct microlaminae structure alternating between the Fe‐rich and Si‐rich bands was observed in our samples for the first time in modern seafloor hydrothermal systems. We propose that its formation was due to the episodic temperature variation of the hydrothermal fluid which controls the biogenic Fe oxyhydroxide formation and passive precipitation of silica in this system. Our results might provide a clue for the formation mechanism of ancient banded iron formations.
Physical associations to spring phytoplankton biomass interannual variability in the U.S. Northeast Continental Shelf
Authors: Saba Vincent S. , Hyde Kimberly J. W. , Rebuck Nathan D. , Friedland Kevin D. , Hare Jonathan A. , Kahru Mati , Fogarty Michael J. 
Published: January 2015

AbstractThe continental shelf of the Northeast United States and Nova Scotia is a productive marine ecosystem that supports a robust biomass of living marine resources. Understanding marine ecosystem sensitivity to changes in the physical environment can start with the first‐order response of phytoplankton (i.e., chlorophyll a), the base of the marine food web. However, the primary physical associations to the interannual variability of chlorophyll a in these waters are unclear. Here we used ocean color satellite measurements and identified the local and remote physical associations to interannual variability of spring surface chlorophyll a from 1998 to 2013. The highest interannual variability of chlorophyll a occurred in March and April on the northern flank of Georges Bank, the western Gulf of Maine, and Nantucket Shoals. Complex interactions between winter wind speed over the Shelf, local winter water levels, and the relative proportions of Atlantic versus Labrador Sea source waters entering the Gulf of Maine from the previous summer/fall were associated with the variability of March/April chlorophyll a in Georges Bank and the Gulf of Maine. Sea surface temperature and sea surface salinity were not robust correlates to spring chlorophyll a. Surface nitrate in the winter was not a robust correlate to chlorophyll a or the physical variables in every case suggesting that nitrate limitation may not be the primary constraint on the interannual variability of the spring bloom throughout all regions. Generalized linear models suggest that we can resolve 88% of March chlorophyll a interannual variability in Georges Bank using lagged physical data.
A practical approach for uncertainty quantification of high‐frequency soil respiration using Forced Diffusion chambers
Authors: Lavoie Martin , Phillips C. L. , Risk David 
Published: January 2015

AbstractThis paper examines the sources of uncertainty for the Forced Diffusion (FD) chamber soil respiration (Rs) measurement technique and demonstrates a protocol for uncertainty quantification that could be appropriate with any soil flux technique. Here we sought to quantify and compare the three primary sources of uncertainty in Rs: (1) instrumentation error; (2) scaling error, which stems from the spatial variability of Rs; and (3) random error, which arises from stochastic or unpredictable variation in environmental drivers and was quantified from repeated observations under a narrow temperature, moisture, and time range. In laboratory studies, we found that FD instrumentation error remained constant as Rs increased. In field studies from five North American ecosystems, we found that as Rs increased from winter to peak growing season, random error increased linearly with average flux by about 40% of average Rs. Random error not only scales with soil flux but scales in a consistent way (same slope) across ecosystems. Scaling error, measured at one site, similarly increased linearly with average Rs, by about 50% of average Rs. Our findings are consistent with previous findings for both soil fluxes and eddy covariance fluxes across other northern temperate ecosystems that showed random error scales linearly with flux magnitude with a slope of ~0.2. Although the mechanistic basis for this scaling of random error is unknown, it is suggestive of a broadly applicable rule for predicting flux random error. Also consistent with previous studies, we found the random error of FD follows a Laplace (double‐exponential) rather than a normal (Gaussian) distribution.
Impact of Concurrent Foot Pain on Health and Functional Status in People with Knee Osteoarthritis: Data From the Osteoarthritis Initiative
Authors: Paterson Kade L. , Hinman Rana S. , Hunter David J. , Wrigley Tim V. , Bennell Kim L. 
Published: January 2015

ObjectiveTo document the prevalence of foot pain and foot pain laterality in people with knee osteoarthritis (OA) and to examine its impact on health and function.MethodsParticipants from the Progression subcohort (n = 1,255, ages 45–79 years) of the Osteoarthritis Initiative with symptomatic tibiofemoral knee OA were included. Prevalence of foot pain, defined as pain in the foot/ankle, and foot pain laterality were determined. Health status was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index, the Short Form‐12 Health Survey, and the Center for Epidemiological Studies Depression Scale. Function was assessed using the 20‐meter walk test (WT) and a repeated chair stand test. Differences in health and functional measures were compared between groups with and without foot pain using multivariate analysis of covariance.ResultsOne‐fourth (n = 317 [25%]) of people with knee OA experienced concurrent foot pain, with the majority (n = 174 [55%]) reporting pain in both feet. After adjusting for covariates, people with foot pain scored worse on all health measures and on the 20‐meter WT, compared to those without (P < 0.05). Differences in health and function were found between the bilateral and ipsilateral foot pain groups compared to those without foot pain (P < 0.05), but no differences were found with the contralateral group.ConclusionFoot pain is common in people with knee OA, and bilateral and ipsilateral foot pain adversely affect health and function, suggesting laterality is important. Further research is needed to establish the mechanism and interaction of pathology at these sites and to evaluate foot pain treatment in this population.
Development of Multinational Definitions of Minimal Clinically Important Improvement and Patient Acceptable Symptomatic State in Osteoarthritis
Authors: Bellamy Nicholas , Hochberg Marc , Tubach Florence , Martin‐Mola Emilio , Awada Hassane , Bombardier Claire , Hajjaj‐Hassouni Najia , Logeart Isabelle , Matucci‐Cerinic Marco , van de Laar Mart , van der Heijde Désirée , Dougados Maxime 
Published: January 2015

ObjectiveThe ability to interpret scores from patient‐reported outcome measures at the individual patient level depends on the availability of valid, clinically meaningful benchmarks of response and state attainment. The goal was to develop multinational estimates for minimal clinically important improvement (MCII) and patient acceptable symptomatic state (PASS).MethodsA multinational sample of patients with osteoarthritis (OA) was evaluated before and 4 weeks after treatment with nonsteroidal antiinflammatory drugs. Patients completed either the Western Ontario and McMaster Osteoarthritis Index (WOMAC) numerical rating scale 3.1 (hip and knee OA) or the Australian/Canadian Index (AUSCAN) numerical rating scale 3.1 (hand OA) before and after treatment. Patients rated the clinical importance of their response to treatment and their satisfaction with the health state achieved, from which multinational MCII and PASS estimates were calculated for both the WOMAC and AUSCAN indices.ResultsA total of 609 patients from 7 countries participated in the study. MCII and PASS estimates varied slightly by instrument and subscale. Absolute (percentage) change for MCII ranged 6–9 (10% to 17%) for WOMAC and 4–9 (8% to 15%) for AUSCAN. PASS estimates ranged 39–48 for WOMAC and 38–45 for AUSCAN. Some between‐country variation was observed in MCII and PASS.ConclusionPreliminary multinational estimates for MCII and PASS have been developed for several countries. Further research is required to evaluate the robustness, temporal consistency, and age‐ and sex‐dependency of the preliminary estimates as well as their generalizability to other countries, languages, cultures, regions, and other condition‐specific outcome measures.
Modification Induced in Makrofol BL 2‐4 Polycarbonate due to Electron Beam Irradiation
Authors: Nouh S. A. , Al‐Shekify L. S. , Benthami K. , Bashter I. I. 
Published: January 2015

ABSTRACTMakrofol BL 2‐4 is an extrusion film based on Makrolon polycarbonate. It is different from Makrofol DE as it comprises excellent die‐cutting performance combined with high light transmission and moderate light scattering properties. It is a polymeric solid‐state nuclear track detector, which has many applications in various radiation detection fields. Samples from Makrofol BL sheets were irradiated using different electron beam doses ranging from 20 to 300 kGy. It is worth mentioning that this report is almost the first one dealing with this topic of material changes using Makrofol BL 2‐4. The resultant effect of electron beam irradiation on the properties of Makrofol has been investigated using X‐ray diffraction, intrinsic viscosity, Fourier transform infrared spectroscopy, thermogravimetric analysis, refractive index, and color difference studies. The results indicate that the electron beam irradiation in the dose range 50–200 kGy led to the dominance of cross‐linking, enhancing the properties of Makrofol.
Divergent Mechanistic Routes for the Formation of gem‐Dimethyl Groups in the Biosynthesis of Complex Polyketides
Authors: Poust Sean , Phelan Ryan M. , Deng Kai , Katz Leonard , Petzold Christopher J. , Keasling Jay D. 
Published: January 2015

AbstractThe gem‐dimethyl groups in polyketide‐derived natural products add steric bulk and, accordingly, lend increased stability to medicinal compounds, however, our ability to rationally incorporate this functional group in modified natural products is limited. In order to characterize the mechanism of gem‐dimethyl group formation, with a goal toward engineering of novel compounds containing this moiety, the gem‐dimethyl group producing polyketide synthase (PKS) modules of yersiniabactin and epothilone were characterized using mass spectrometry. The work demonstrated, contrary to the canonical understanding of reaction order in PKSs, that methylation can precede condensation in gem‐dimethyl group producing PKS modules. Experiments showed that both PKSs are able to use dimethylmalonyl acyl carrier protein (ACP) as an extender unit. Interestingly, for epothilone module 8, use of dimethylmalonyl‐ACP appeared to be the sole route to form a gem‐dimethylated product, while the yersiniabactin PKS could methylate before or after ketosynthase condensation.
Indolo‐Phakellins as β5‐Specific Noncovalent Proteasome Inhibitors
Authors: Beck Philipp , Lansdell Theresa A. , Hewlett Nicole M. , Tepe Jetze J. , Groll Michael 
Published: January 2015

AbstractThe proteasome represents an invaluable target for the treatment of cancer and autoimmune disorders. The application of proteasome inhibitors, however, remains limited to blood cancers because their reactive headgroups and peptidic scaffolds convey unfavorable pharmacodynamic properties. Thus, the discovery of more drug‐like lead structures is indispensable. In this study, we present the first structure of the proteasome in complex with an indolo‐phakellin that exhibits a unique noncovalent binding mode unparalleled by all hitherto reported inhibitors. The natural product inspired pentacyclic alkaloid binds solely and specificially into the spacious S3 subpocket of the proteasomal β5 substrate binding channel, gaining major stabilization through halogen bonding with the protein backbone. The presented compound provides an ideal scaffold for the structure‐based design of subunit‐specific nonpeptidic proteasome‐blockers.
Double Heteroatom Functionalization of Arenes Using Benzyne Three‐Component Coupling
Authors: García‐López José‐Antonio , Çetin Meliha , Greaney Michael F. 
Published: January 2015

AbstractArynes participate in three‐component coupling reactions with N, S, P, and Se functionalities to yield 1,2‐heteroatom‐difunctionalized arenes. Using 2‐iodophenyl arylsulfonates as benzyne precursors, we could effectively add magnesiated S‐, Se‐, and N‐nucleophilic components to the strained triple bond. In the same pot, addition of electrophilic N, S, or P reagents and a copper(I) catalyst trapped the intermediate aryl Grignard to produce a variety of 1,2‐difunctionalized arenes.
The organic electrochemical transistor for biological applications
Authors: Strakosas Xenofon , Bongo Manuelle , Owens Róisín M. 
Published: January 2015

ABSTRACTThe rising field of bioelectronics, which couples the realms of electronics and biology, holds huge potential for the development of novel biomedical devices for therapeutics and diagnostics. Organic electronic devices are particularly promising; the use of robust organic electronic materials provides an ideal biointerface due to their reported biocompatibility, and mechanical matching between the sensor element and the biological environment, are amongst the advantages unique to this class of materials. One promising device emerging from this field is the organic electrochemical transistor (OECT). Arguably, the most important feature of an OECT is that it provides local amplification and as such can be used as a high fidelity transducer of biological events. Additionally, the OECT combines properties and characteristics that can be tuned for a wide spectrum of biological applications. Here, we frame the development of the OECT with respect to its underlying optimization for a variety of different applications, including ion sensing, enzymatic sensing, and electrophysiology. These applications have allowed the development of OECTs to sense local ionic/biomolecular and single cell activity, as well characterization of tissue and even monitoring of function of whole organs. The body of work reviewed here demonstrates that the OECT is an extremely versatile device that emerges as an important player for therapeutics and diagnostics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41735.
Flame‐retardancy properties of tris(2‐hydroxyethyl) isocyanurate based charring agents on polypropylene
Authors: Chen Wenyan , Liu Gousheng 
Published: January 2015

ABSTRACTTris(2‐hydroxyethyl) isocyanurate based charring agent (TBCA) was synthesized by melt polycondensation with tris(2‐hydroxyethyl) isocyanurate (THEIC) and terephthalic acid as raw materials. It was characterized by Fourier transform infrared spectroscopy, elemental analysis, 1H‐NMR, and thermogravimetric analysis (TGA). TBCA was blended with ammonium polyphosphate (APP) to form an intumescent flame retardant (IFR) for polypropylene (PP). The charring properties of TBCA was tested by flame retardancy in the PP/APP/TBCA (PP/IFR2) composite and compared with that of the PP/APP/THEIC (PP/IFR1) composite. The results show that PP/IFR2 had lower flame‐retardant properties but better water resistance than that of the PP/IFR1 composite because PP/IFR2 could still obtain a V‐0 rating after it had been soaked in water at 70°C for 96 h, whereas PP/IFR1 could not achieve any rating after 36 h. Their combustion performance was further evaluated by a cone calorimeter test, their thermal degradation processes were studied by TGA, and the morphology of the char residue was observed by scanning electron microscopy. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41810.
Ultrathin and nanofibers via room temperature electrospinning from trifluoroacetic acid solutions of untreated lignocellulosic sisal fiber or sisal pulp
Authors: Rodrigues Bruno V. M. , Ramires Elaine C. , Santos Rachel P. O. , Frollini Elisabete 
Published: January 2015

ABSTRACTLignocellulosic sisal fiber (LSF) and sisal pulp (SP) were electrospun at room temperature from solutions in trifluoroacetic acid (TFA) prepared at concentrations of 2 × 10−2g mL−1and 3 × 10−2g mL−1, respectively. Scanning electron microscopy images of the electrospun LSF showed fibers with diameters ranging from 120 to 510 nm. The presence of defects decreased along with increasing the flow rate of the SP solution, which generated nanofibers and ultrathin fibers with diameters in the range of 40–60 (at 5.5 µL min−1) up to 90–200 nm (at 65.5 µL min−1). Despite the known ability of TFA to esterify the hydroxyl groups present in the starting materials, the Fourier transform infrared spectra indicated the absence of trifluoroacetyl groups in the electrospun samples. The thermal stability of the final materials proved suitable for many applications even though some differences were observed relative to the starting materials. This study demonstrated a feasible novel approach for producing nano/ultrathin fibers from lignocellulosic biomass or its main component, which allows for a wide range of applications for these materials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41826.
Effects of substitution for carbon black with graphene oxide or graphene on the morphology and performance of natural rubber/carbon black composites
Authors: Yang Ganwei , Liao Zhenfei , Yang Zhijun , Tang Zhenghai , Guo Baochun 
Published: January 2015

ABSTRACTIn this study, nanosheets including graphene oxide (GO) and reduced graphene oxide (rGO), were incorporated into natural rubber (NR), to study the effects of substituting GO or rGO for carbon black (CB) on the structure and performance of NR/CB composites. The morphological observations revealed the dispersion of CB was improved by partially substituting nanosheets for CB. The improvements in static and dynamic mechanical properties were achieved at small substitution content of GO or rGO nanosheets. With substitution of rGO nanosheets, significant improvement in flex cracking resistance was achieved. NR/CB/rGO (NRG) composites has a much lower heat build‐up value compared with NR/CB/GO (NG) composites at a high load of nanosheets. However, both GO and rGO tended to aggregate at a high concentration, which led to the poor efficiency on enhancing the dynamic properties, or even deteriorate the performance of rubber composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41832.
Direct N‐Methylation Reaction Using DMSO as One‐Carbon Bridge: Convenient Access to Heterocycle‐Containing β‐Amino Ketones
Authors: Sun Kai , Wang Xin , Jiang Yongqing , Lv Yunhe , Zhang Liping , Xiao Beibei , Li Donghui , Zhu Zhonghong , Liu Lin 
Published: January 2015

AbstractA novel oxidative CS bond cleavage reaction of DMSO for dual CC and CN bond formation is described. A series of acetyl heteroarenes could be selectively converted into the corresponding β‐amino ketones, which are frequently found in biologically active compounds and pharmaceuticals. DMSO acted in this reaction not only as the solvent but also as a one‐carbon bridge.