bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Quantitative Approach to Assessing Sovereign Default Risk in Resource‐Rich Emerging Economies
Authors: Nyambuu Unurjargal , Bernard Lucas 
Published: May 2015

AbstractThe problem of sovereign default is a tricky one for bankers, policy makers, politicians and investors alike. Purely financial models are likely to miss nuance and cultural idiosyncrasies. Nonetheless, risk metrics must play a role. Using a stochastic growth model in an open economy, we propose a Kealhofer, McQuown and Vasicek (KMV)‐style approach for assessing sovereign default risk in resource‐rich emerging economies. As is well known, financial effects, specifically external debt, can make a country vulnerable to economic shocks. Excessive external debt is, thus, a prime indicator for financial health in both resource‐poor and resource‐rich countries; yet, safe ratios are difficult to determine. Using a straightforward and easily implementable methodology, we show how optimal debt ratios may be used to define a ‘distance from default’ indicator variable. Further, we demonstrate that this is a plausible risk metric for a number of different developing countries, including representatives from Latin America, Africa and Asia. Copyright © 2015 John Wiley & Sons, Ltd.
An automated perfusion bioreactor for the streamlined production of engineered osteogenic grafts
Authors: Ding Ming , Henriksen Susan S. , Wendt David , Overgaard Søren 
Published: May 2015

AbstractA computer‐controlled perfusion bioreactor was developed for the streamlined production of engineered osteogenic grafts. This system automated the required bioprocesses, from the initial filling of the system through the phases of cell seeding and prolonged cell/tissue culture. Flow through chemo‐optic micro‐sensors allowed to non‐invasively monitor the levels of oxygen and pH in the perfused culture medium throughout the culture period. To validate its performance, freshly isolated ovine bone marrow stromal cells were directly seeded on porous scaffold granules (hydroxyapatite/β‐tricalcium‐phosphate/poly‐lactic acid), bypassing the phase of monolayer cell expansion in flasks. Either 10 or 20 days after culture, engineered cell‐granule grafts were implanted in an ectopic mouse model to quantify new bone formation. After four weeks of implantation, histomorphometry showed more bone in bioreactor‐generated grafts than cell‐free granule controls, while bone formation did not show significant differences between 10 days and 20 days of incubation. The implanted granules without cells had no bone formation. This novel perfusion bioreactor has revealed the capability of activation larger viable bone graft material, even after shorter incubation time of graft material. This study has demonstrated the feasibility of engineering osteogenic grafts in an automated bioreactor system, laying the foundation for a safe, regulatory‐compliant, and cost‐effective manufacturing process. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 532–537, 2016.
Reduced oxidative stress in primary human cells by antioxidant released from nanoporous alumina
Authors: Pujari‐Palmer Shiuli , Pujari‐Palmer Michael , Karlsson Ott Marjam 
Published: May 2015

AbstractNanoporous alumina elicits different inflammatory responses dependent on pore size, such as increased complement activation and reactive oxygen species (ROS) production, on 200 versus 20 nm pores. In this study, we attempt to further modulate inflammatory cell response by loading nanoporous alumina membranes (20, 100, and 200 nm pores), with an antioxidant, Trolox, for controlled drug release. For mononuclear cells (MNC) no difference in cell response, due to pore size, was seen when cultured on nonloaded membranes. However, when exposed to membranes loaded with Trolox, 100 uM was enough to quench ROS by more than 95% for all pore sizes. Polymorphonuclear cells (PMNC) produced significantly more ROS when exposed to 20 versus 100 nm pores. For Trolox loaded membranes, this trend reversed, due to slower release of antioxidant from the 20 nm pores. Furthermore, Trolox exhibited a unique effect on PMNCs that has not previously been reported: It delayed the production of ROS in a manner distinct from antioxidant activity. The present study confirms that nanoporous alumina is a suitable vehicle for drug delivery, and that Trolox can successfully modulate the inflammatory response of both MNC and PMNCs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 568–575, 2016.
Evaluation of a performance appraisal framework for radiation therapists in planning and simulation
Authors: Becker Jillian , Bridge Pete , Brown Elizabeth , Lusk Ryan , Ferrari‐Anderson Janet 
Published: May 2015

AbstractIntroductionConstantly evolving technology and techniques within radiation therapy require practitioners to maintain a continuous approach to professional development and training. Systems of performance appraisal and adoption of regular feedback mechanisms are vital to support this development yet frequently lack structure and rely on informal peer support.MethodsA Radiation Therapy Performance Appraisal Framework (RT‐PAF) for radiation therapists in planning and simulation was developed to define expectations of practice and promote a supportive and objective culture of performance and skills appraisal. Evaluation of the framework was conducted via an anonymous online survey tool. Nine peer reviewers and fourteen recipients provided feedback on its effectiveness and the challenges and limitations of the approach.ResultsFindings from the evaluation were positive and suggested that both groups gained benefit from and expressed a strong interest in embedding the approach more routinely. Respondents identified common challenges related to the limited ability to implement suggested development strategies; this was strongly associated with time and rostering issues.ConclusionsThis framework successfully defined expectations for practice and provided a fair and objective feedback process that focussed on skills development. It empowered staff to maintain their skills and reach their professional potential. Management support, particularly in regard to provision of protected time was highlighted as critical to the framework's ongoing success. The demonstrated benefits arising in terms of staff satisfaction and development highlight the importance of this commitment to the modern radiation therapy workforce.
Optimization of a colorimetric method to determine trace urea in seawater
Authors: Chen Li , Ma Jian , Huang Yang , Dai Minhan , Li Xiaolin 
Published: May 2015

AbstractThis study optimized the experimental conditions for the analysis of dissolved urea in seawater. The kinetics of the colorimetric reaction of urea with diacetyl monoxime were studied under different conditions: reagent stability, pH, and reaction temperature and time, based on which robust procedures were developed for both normal (> 100 nmol L−1, using a five centimeter cuvette) and trace (<100 nmol L−1, using a one meter path length capillary cell) levels of dissolved urea. Our trace level method showed very high sensitivity (detection limit of 1.2 nmol L−1) and high reproducibility (relative standard deviations were 0.29–1.09%), which was a significant improvement as compared to what was reported previously. The current method afforded a more stable colorimetric product, which provided better reproducibility when a large number of samples were analyzed. The normal‐level method was applied to studying the urea distribution in estuarine surface water, and the trace‐level method was applied to studying the vertical distribution of urea in the South China Sea basin (> 4000 m).
Assessment of the radio 3H‐CH4 tracer technique to measure aerobic methane oxidation in the water column
Authors: Bussmann Ingeborg , Matousu Anna , Osudar Roman , Mau Susan 
Published: May 2015

AbstractMicrobial methane oxidation rates in ocean and freshwater systems reveal how much of emitted methane from the sediments is oxidized to CO2 and how much can reach the atmosphere directly. The tracer‐method using 3H‐CH4 provides a way to measure methane oxidation rates even in water with low methane concentrations. We assessed this method by implementing several experiments, collecting data from various environments, and including recent literature concerning the method to identify any uncertainties that should be considered. Our assessment reveals some difficulties of the method but also reassures previous assumptions to be correct. Some of the difficulties are hardly to be avoided, such as incubating all samples at the right in situ temperature or limiting the variability of methane oxidation rate measurements in water of low methanotrophic activity. Other details, for example, quickly measuring the total radioactivity after stopping the incubation, are easy to adapt in each laboratory. And yet other details as shaking during incubation and bottle size seem to be irrelevant. With our study, we hope to improve and to encourage future measurements of methane oxidation rates in different environments and to provide a standard procedure of methane oxidation rate measurements to make the data better comparable.
Alkaline‐extractable silicon from land to ocean: A challenge for biogenic silicon determination
Authors: Barão Lúcia , Vandevenne Floor , Clymans Wim , Frings Patrick , Ragueneau Olivier , Meire Patrick , Conley Daniel J. , Struyf Eric 
Published: May 2015

AbstractThe biogeochemical cycling of silicon (Si) along the land‐to‐ocean continuum is studied by a variety of research fields and for a variety of scientific reasons. However, there is an increasing need to refine the methodology and the underlying assumptions used to determine biogenic silica (BSi) concentrations. Recent evidence suggests that contributions of nonbiogenic sources of Si dissolving during alkaline extractions, not corrected by standard silicate mineral dissolution correction protocols, can be substantial. The ratio between dissolved Si and aluminum (Al) monitored continuously during the alkaline extraction can be used to infer the origin of the Si fractions present. In this study, we applied both a continuous analysis method (0.5 M NaOH) and a traditional 0.1 M Na2CO3 extraction to a wide array of samples: (1) terrestrial vegetation, (2) soils from forest, cropland and pasture, (3) lake sediments, (4) suspended particulate matter and sediments from rivers, (5) sediments from estuaries and salt marshes and (6) ocean sediments. Our results indicate that the 0.1 M Na2CO3 extraction protocol can overestimate the BSi content, by simultaneously dissolving Si fractions of nonbiogenic origin that may represent up to 100% of the Si traditionally considered as biogenic, hampering interpretation especially in some deeper soil horizons, rivers and coastal oceanic sediments. Moreover, although the term amorphous Si was coined to reflect a growing awareness of nonbiogenic phases we show it is actually inappropriate in samples where silicate minerals may account for a large part of the extracted Si even after linear mineral correction.
Physical Continuity and Vertical Alignment of Block Copolymer Domains by Kinetically Controlled Electrospray Deposition
Authors: Hu Hanqiong , Choo Youngwoo , Feng Xunda , Osuji Chinedum O. 
Published: May 2015

The fabrication of block copolymer (BCP) thin films is reported with vertically aligned cylindrical domains using continuous electrospray deposition onto bare wafer surfaces. The out‐of‐plane orientation of hexagonally packed styrene cylinders is achieved in the “fast‐wet” deposition regime in which rapid evaporation of the solvent in deposited droplets of polymer solution drives the vertical alignment of the self‐assembled structure. Thermally activated crosslinking of the polybutadiene matrix provides kinetic control of the morphology, freezing the vertical alignment and preventing relaxation of the system to its preferred parallel orientation on the nontreated substrate. Physically continuous vertically oriented domains can be achieved over several micrometers of film thickness. The ability of electrospray deposition to fabricate well‐ordered and aligned BCP films on nontreated substrates, the low amount of material used relative to spin‐coating, and the continuous nature of the deposition may open up new opportunities for BCP thin films.
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Dual Sulfide–Disulfide Crosslinked Networks with Rapid and Room Temperature Self‐Healability
Authors: An So Young , Noh Seung Man , Nam Joon Hyun , Oh Jung Kwon 
Published: May 2015

Polymer‐based crosslinked networks with intrinsic self‐repairing ability have emerged due to their built‐in ability to repair physical damages. Here, novel dual sulfide–disulfide crosslinked networks (s‐ssPxNs) are reported exhibiting rapid and room temperature self‐healability within seconds to minutes, with no extra healing agents and no change under any environmental conditions. The method to synthesize these self‐healable networks utilizes a combination of well‐known crosslinking chemistry: photoinduced thiol‐ene click‐type radical addition, generating lightly sulfide‐crosslinked polysulfide‐based networks with excess thiols, and their oxidation, creating dynamic disulfide crosslinkages to yield the dual s‐ssPxNs. The resulting s‐ssPxN networks show rapid self‐healing within 30 s to 30 min at room temperature, as well as self‐healing elasticity with reversible viscoelastic properties. These results, combined with tunable self‐healing kinetics, demonstrate the versatility of the method as a new means to synthesize smart multifunctional polymeric materials.
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Longitudinal assessment of spinal cord injuries in nonhuman primates with quantitative magnetization transfer
Authors: Wang Feng , Li Ke , Mishra Arabinda , Gochberg Daniel , Min Chen Li , Gore John C. 
Published: May 2015

PurposeThis study aimed to evaluate the reproducibility and specificity of quantitative magnetization transfer (qMT) imaging for monitoring spinal cord injuries (SCIs).MethodsMRI scans were performed in anesthetized monkeys at 9.4T, before and serially after a unilateral lesion of the cervical spinal cord. A two‐pool fitting model was used to derive qMT parameters.ResultsqMT measures were reproducible across normal subjects, with an average pool size ratio (PSR) of 0.086 ± 0.003 (mean ± SD) for gray matter, and 0.120 ± 0.005 for white matter, respectively. Compared with normal gray matter, the PSR of abnormal tissues rostral and caudal to the injury site decreased by 19.5% (P < 0.05), while the PSR of the cyst‐like volume decreased drastically weeks after SCI. Strong correlations in cyst‐like regions were observed between PSR and other MRI measures including longitudinal relaxation rate (R1), apparent diffusion coefficient and fractional anisotropy (FA). Decreased PSR and FA values correlated well with demyelination in abnormal tissues.ConclusionThe qMT parameters provide robust and specific information about the molecular and cellular changes produced by SCI. PSR detected demyelination and loss of macromolecules in abnormal tissue regions rostral and caudal to the cyst/lesion sites. Magn Reson Med 75:1685–1696, 2016. © 2015 Wiley Periodicals, Inc.
Psychological factors at early stage of treatment as predictors of receiving chemotherapy at the end of life
Authors: Fujisawa Daisuke , Temel Jennifer S. , Traeger Lara , Greer Joseph A. , Lennes Inga T. , Mimura Masaru , Pirl William F. 
Published: May 2015

AbstractIntroductionAdministration of chemotherapy in the last 14 days of life is a widely recognized indicator of poor end‐of‐life (EOL) care. The current study aimed to investigate predictors of this outcome, focusing on patients' self‐reported psychological symptoms.Methods and MaterialsThis is a secondary analysis of a randomized controlled trial that examined the efficacy of early palliative care integrated with standard oncology practice in patients with metastatic non‐small cell lung cancer (NSCLC). We analyzed associations between receipt of chemotherapy within 14 days of death and demographic, clinical, and quality‐of‐life variables in the 125 patients who received chemotherapy in the course of their illness and died during the 50‐month follow‐up.ResultsTwenty‐five patients (20%) received chemotherapy within the last 14 days of their life. Among demographic and clinical variables, only route of chemotherapy was significantly associated with receipt of chemotherapy within 14 days of death (oral 34.1% vs. intravenous (IV) 12.3%, p < 0.05). In the subsample of participants who received IV chemotherapy as their last regimen, greater anxiety and depression and lower quality of life in emotional, social, and existential domains were associated with greater likelihood of receiving chemotherapy at the EOL. These associations were not observed in patients who received oral chemotherapy as their last regimen.ConclusionAnxiety, depression, and worse psychological quality of life at early stage of treatment may be associated with the receipt of IV chemotherapy at the EOL. Further research is needed to examine how these factors might influence decision‐making about the discontinuation of chemotherapy at the EOL. Copyright © 2015 John Wiley & Sons, Ltd.
Understanding constraints to the transformation rate of global energy infrastructure
Authors: Lane Joe L. , Smart Simon , Schmeda‐Lopez Diego , Hoegh‐Guldberg Ove , Garnett Andrew , Greig Chris , McFarland Eric 
Published: May 2015

A massive transformation of the global energy supply system is required if deep reductions in atmospheric carbon dioxide emissions are to be achieved. A top–down review of historical data and energy forecasts provides a perspective on the magnitude of the challenge. Global engineering capability has expanded significantly over the last two decades, accommodating more than 100 GW/year increase in electricity generation infrastructure. However, business‐as‐usual demand forecasts to 2050 will require more than double the global rates of energy project execution. Transforming to a low‐carbon energy supply mix requires 30–70 GW/year of additional infrastructure, due to the increased reliance on intermittent renewables, and the earlier‐than‐expected replacement of existing coal power plants. Although all power systems share many similar subsystems that will need to be delivered regardless of the technology type, meeting the extra demands for engineering design, construction and/or supply chains may not be possible. The discussion focuses only on physical limitations of electricity generation, specifically around the timing and scale of retiring and/or replacing coal‐fired power generation capacity to meet the International Energy Agency's two‐degree scenario. We ignore the economics and politics of the transition scenarios and the transformation of the transportation and industrial sectors. What is clear is that the longer the delay in starting a significant transformation, the greater the challenge will become. Decision makers must understand the constraints to technology transitions to deliver effective policy. A broad international consensus is not required, instead reaching agreements and developing economically sustainable pathways to technology transitions in the United States, China, and India is more likely to be successful and the only means for significantly curbing global emissions. WIREs Energy Environ 2016, 5:33–48. doi: 10.1002/wene.177This article is categorized under:

Energy Systems Economics > Systems and Infrastructure
Energy and Climate > Systems and Infrastructure
Energy Policy and Planning > Systems and Infrastructure
Energy Research & Innovation > Economics and Policy
Persistence of Methanosaeta populations in anaerobic digestion during process instability
Authors: Chen Si , He Qiang 
Published: May 2015

Abstract
Anaerobic digestion is a sustainable technology for the treatment of organic waste and production of biogas. Acetoclastic methanogenesis accounts for the majority of methane production in anaerobic digestion. Therefore, sustaining robust acetoclastic methanogens is important for stable process performance. Due to faster growth kinetics at high acetate concentrations, it has been considered that Methanosarcina would be more prevalent than Methanosaeta in unstable anaerobic digestion processes which frequently experience high acetate levels. Methanogen population dynamics were monitored in multiple continuous anaerobic digesters for 500 days. Results from quantitative polymerase chain reaction analysis show that Methanosaeta dominated over Methanosarcina in anaerobic digestion at high acetate levels up to 44 mM, suggesting the potential of Methanosaeta as a robust and efficient acetoclastic candidate for resilient anaerobic methane conversion. Further efforts are needed to identify mechanisms contributing to the unexpected competitiveness of these methanogens at high acetate levels observed in this study.
Amplitude and frequency modulation of the small scales in a jet
Authors: Fiscaletti D. , Ganapathisubramani B. , Elsinga G. E. 
Published: May 2015

The present study is an experimental investigation of the relationship between the large- and small-scale motions in the far field of an air jet at high Reynolds number. In the first part of our investigation, the analysis is based on time series of hot-wire anemometry (HWA), which are converted into space series after applying the Taylor hypothesis. By using a spectral filter, two signals are constructed, one representative of the large-scale motions ($2{\it\lambda}_{T}-L$, where${\it\lambda}_{T}$is the Taylor length scale, and$L$is the integral length scale) and the other representative of the small-scale motions ($1.5{-}5{\it\eta}$, where${\it\eta}$is the Kolmogorov length scale). The small-scale signal is found to be modulated both in amplitude and in frequency by the energy-containing scales in an analogous way, both at the centreline and around the centreline. In particular, for positive fluctuations of the large-scale signal, the small-scale signal is locally stronger in amplitude (amplitude modulation), and it locally exhibits a higher number of local maxima and minima (frequency modulation). The extent of this modulation is quantified based on the strength of the large-scale fluctuations. The response of the small-scale motions to amplitude modulation can be considered instantaneous, being on the order of one Kolmogorov time scale. In the second part of our investigation we use long-range${\it\mu}$PIV to study the behaviour of the small-scale motions in relation to their position in either high-speed or low-speed regions of the flow. The spatially resolved velocity vector fields allow us to quantify amplitude modulation directly in physical space. From this direct estimation in physical space, amplitude modulation is only 25 % of the value measured from HWA. The remaining 75 % comes from the fixed spectral band filter used to obtain the large- and small-scale signals, which does not consider the local convection velocity. A very similar overestimation of amplitude modulation when quantified in the time-frame is also obtained analytically. Furthermore, the size of the structures of intense vorticity does not change significantly in relation to the large-scale velocity fluctuation, meaning that there is no significant spatial frequency modulation. The remaining amplitude modulation in space can be explained as a statistical coupling between the strength of the structures of vorticity and their preferential location inside large-scale high-velocity regions. Finally, the implications that the present findings have on amplitude and frequency modulation in turbulent boundary layers (TBLs) are discussed.