bluuebunny/crossref_metadata_2025 huggingface dataset:
Tension pneumocephalus - a rare but treatable cause of rapid neurological deterioration in traumatic brain injury. A case report
Authors: Komolafe EO , Faniran E
Published: March 2012

Pneumocephalus is a frequent complication following head injury and craniotomies. It can become an acute neurosurgical emergency when associated with raised intracranial pressure and neurological deterioration. Early diagnosis and timely appropriate intervention will reduce morbidity and unnecessary mortality from a case as this.
A model study of the Eastern Mediterranean ozone levels during the hot summer of 2007
Authors: Hodnebrog Ø. , Solberg S. , Stordal F. , Svendby T. M. , Simpson D. , Gauss M. , Hilboll A. , Pfister G. G. , Turquety S. , Richter A. , Burrows J. P. , Denier van der Gon H. A. C.
Published: March 2012

Abstract. The hot summer of 2007 in Southeast Europe has been studied using two regional atmospheric chemistry models; WRF-Chem and EMEP MSC-W. The region was struck by three heat waves and a number of forest fire episodes, greatly affecting air pollution levels. We have focused on ozone and its precursors using state-of-the-art inventories for anthropogenic, biogenic and forest fire emissions. The models have been evaluated against measurement data, and processes leading to ozone formation have been quantified. Heat wave episodes are projected to occur more frequently in a future climate, and therefore this study also makes a contribution to climate change research. The plume from the Greek forest fires in August 2007 is clearly seen in satellite observations of CO and NO2 columns, showing extreme levels of CO in and downwind of the fires. Model simulations reflect the location and influence of the fires relatively well, but the modelled magnitude of CO in the plume core is too low. Most likely, this is caused by underestimation of CO in the emission inventories, suggesting that the CO/NOx ratios of fire emissions should be re-assessed. Moreover, higher maximum values are seen in WRF-Chem than in EMEP MSC-W, presumably due to differences in plume rise altitudes as the first model emits a larger fraction of the fire emissions in the lowermost model layer. The model results are also in fairly good agreement with surface ozone measurements. Biogenic VOC emissions reacting with anthropogenic NOx emissions are calculated to contribute significantly to the levels of ozone in the region, but the magnitude and geographical distribution depend strongly on the model and biogenic emission module used. During the July and August heat waves, ozone levels increased substantially due to a combination of forest fire emissions and the effect of high temperatures. We found that the largest temperature impact on ozone was through the temperature dependence of the biogenic emissions, closely followed by the effect of decreased dry deposition. The impact of high temperatures on the ozone chemistry was much lower. The results suggest that forest fire emissions, and the temperature effect on biogenic emissions and dry deposition, will potentially lead to substantial ozone increases in a warmer climate.
Integrative analysis of Geobacter spp. and sulfate-reducing bacteria during uranium bioremediation
Authors: Barlett M. , Zhuang K. , Mahadevan R. , Lovley D.
Published: March 2012

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.
A process-based fire parameterization of intermediate complexity in a Dynamic Global Vegetation Model
Authors: Li F. , Zeng X. D. , Levis S.
Published: March 2012

Abstract. A process-based fire parameterization of intermediate complexity has been developed for global simulations in the framework of a Dynamic Global Vegetation Model (DGVM) in an Earth System Model (ESM). Burned area in a grid cell is estimated by the product of fire counts and average burned area per fire. The scheme comprises three parts: fire occurrence, fire spread, and fire impact. In the fire occurrence part, fire counts rather than fire occurrence probability is calculated in order to capture the observed high burned area fraction in regions where fire occurs frequently. In the fire spread part, post-fire region of a fire is assumed to be elliptical in shape. Mathematical properties of ellipses and mathematical derivation are applied to remove redundant and unreasonable equation and assumptions in existing fire spread parameterization. In the fire impact part, trace gas and aerosol emissions due to biomass burning are estimated, which offers an interface with atmospheric chemistry and aerosol models in ESMs. In addition, flexible time-step length makes the new fire parameterization easily applied to various DGVMs. Global performance of the new fire parameterization is assessed by using an improved version of the Community Land Model version 3 with the Dynamic Global Vegetation Model (CLM-DGVM). Simulations are compared against the latest satellite-based Global Fire Emission Database version 3 (GFED3) for 1997–2004. Results show that simulated global totals and spatial patterns of burned area and fire carbon emissions, global annual burned area fractions for various vegetation types and interannual variability of burned area are in close agreement with the GFED3, and more accurate than CLM-DGVM simulations with the commonly used Glob-FIRM fire parameterization and the old fire module of CLM-DGVM. Furthermore, the average relative error of simulated trace gas and aerosol emissions due to biomass burning is 7 %. Results suggest that the new fire parameterization may improve the global performance of ESMs and help to quantify fire-vegetation-climate interactions on a global scale and from an earth system perspective.
New insights on the role of organic speciation in the biogeochemical cycle of dissolved cobalt in the southeastern Atlantic and the Southern Ocean
Authors: Bown J. , Boye M. , Nelson D. M.
Published: March 2012

Abstract. The organic speciation of dissolved cobalt was investigated in the subtropical region of the southeastern Atlantic, and in the Antarctic Circumpolar Current (ACC) and the northern Weddell Gyre in the Southern Ocean between 33°58′S and 57°33′S along the Greenwich Meridian during the austral summer of 2008. The organic speciation of cobalt was determined by Competing Ligand Exchange Adsorptive Cathodic Stripping Voltammetry (CLE-AdCSV) using nioxime as a competing ligand. The conditional stability constants (log K'CoL) of the organic complexes of Co ranged between 17.9 and 20.1, and the concentrations of the organic ligands (L) between 26 and 73 pM. Most dissolved cobalt (DCo) was organically complexed in the water-column (60 to ≥99.9 %). There were clear vertical and meridional patterns in the distribution of L and the organic speciation of DCo along the section. These patterns suggested a biological source of the organic ligands in the surface waters of the subtropical domain and northern subantarctic region, potentially driven by the cyanobacteria, and a removal of the organic Co by direct or indirect biological uptake. The highest L:DCo ratio (e.g. 5.81 ± 1.07 pM pM–1) observed in these surface waters reflected the combined effects of ligand production and consumption of DCo. As a result of these combined effects, the calculated concentrations of free, unbound Co ([Co′]) in subtropical and subantarctic surface waters were very low, generally between 10–19 and 10–17 M. In intermediate and deep waters, the South African margins can be a source of organic ligands, as it was suggested to be for DCo (Bown et al., 2011), although a significant portion of DCo (up to 15 %) can be stabilized and transported as inorganic species in those DCo-enriched water-masses. Contrastingly, the distribution of L did not suggest an intense biological production of L around the Antarctic Polar Front where a diatom bloom had recently occurred. Here [Co′] can be several orders of magnitude higher than those reported in the subtropical domain, suggesting that cobalt limitation was unlikely in the ACC domain. The almost invariant L:DCo ratio of ~1 recorded in these surface waters also reflected the conservative behaviours of both the organic ligands and DCo. In deeper waters relatively higher ligand concentrations were observed in waters previously identified as DCo sources (Bown et al., 2011). At those depths the eastward increase of DCo could be associated with a large scale transport and remineralisation of DCo as organic complexes; here, the fraction stabilized as inorganic Co was much lower but still significant (up to 25 %) in the low oxygenated Upper Circumpolar Deep Waters. The organic speciation may thus be a central factor in the biogeochemical cycle of DCo in those areas, playing a major role in the bioavailability and the geochemistry of Co.
Quantifying the ocean's role in glacial CO2 reductions
Authors: Chikamoto M. O. , Abe-Ouchi A. , Oka A. , Ohgaito R. , Timmermann A.
Published: March 2012

Abstract. A series of Last Glacial Maximum (LGM) marine carbon cycle sensitivity experiments is conducted to test the effect of different physical processes, as simulated by two atmosphere-ocean general circulation model (AOGCM) experiments, on atmospheric pCO2. One AOGCM solution exhibits an increase in North Atlantic Deep Water (NADW) formation under glacial conditions, whereas the other mimics an increase in Antarctic Bottom Water (AABW) associated with a weaker NADW. None of these sensitivity experiments reproduces the observed magnitude of glacial/interglacial pCO2 changes. However, to explain the reconstructed vertical gradient of dissolved inorganic carbon (DIC) of 40 mmol m−3 a marked enhancement in AABW formation is required. Furthermore, for the enhanced AABW sensitivity experiment the simulated stable carbon isotope ratio (δ13C) decreases by 0.4‰ at intermediate depths in the South Atlantic in accordance with sedimentary evidence. The shift of deep and bottom water formation sites from the North Atlantic to the Southern Ocean increases the total preformed nutrient inventory, so that the lowered efficiency of Southern Ocean nutrient utilization in turn increases atmospheric pCO2. This change eventually offsets the effect of an increased abyssal carbon pool due to stronger AABW formation. The effects of interhemispheric glacial sea-ice changes on atmospheric pCO2 oppose each other. Whereas, extended sea-ice coverage in the Southern Hemisphere reduces the air-sea gas exchange of CO2 in agreement with previous theoretical considerations, glacial advances of sea-ice in the Northern Hemisphere lead to a weakening of the oceanic carbon uptake through the physical pump. Due to enhanced gas solubility associated with lower sea surface temperature, both glacial experiments generate a reduction of atmospheric pCO2 by about 20–23 ppmv. The sensitivity experiments presented here demonstrate the presence of compensating effects of different physical processes in the ocean on glacial CO2 and the difficulty of finding a simple explanation of the glacial CO2 problem by invoking ocean dynamical changes.
Vegetation-climate interactions in the warm mid-Cretaceous
Authors: Zhou J. , Poulsen C. J. , Rosenbloom N. , Shields C. , Briegleb B.
Published: March 2012

Abstract. Vegetation-climate interactions are thought to have amplified polar warmth during past warm periods. Here, we explore the vegetation-climate interactions in the mid-Cretaceous using a fully coupled ocean-atmosphere general circulation model with a dynamic vegetation component. We run simulations with 1x, 10x and 16x pre-industrial atmospheric CO2. Results show that forests expand from mid-latitudes to high latitudes as CO2 increases from 1x to 10x and 16x, mainly due to the CO2-induced warming. This expansion of mid-to-high latitude forests are largely supported by the distribution of mid-Cretaceous fossil woods and coal deposits. Globally, the presence of vegetation increases mean annual temperature and precipitation by 0.9 °C and 0.11 mm day−1 relative to bare ground. High-latitude warming induced by the presence of vegetation (∼1.9 °C) is less than half of that reported in previous studies. The weaker warming here is mainly due to less pronounced albedo feedbacks, and to a less extent, reduced poleward heat transport via weakening of the meridional overturning circulation. Our results suggest that other mechanisms in addition to high atmospheric CO2 and high-latitude vegetation are required to maintain the polar warmth.
Why a regional approach to postgraduate water education makes sense – the WaterNet experience in Southern Africa
Authors: Jonker L. , Van der Zaag P. , Gumbo B. , Rockström J. , Love D. , Savenije H. H. G.
Published: March 2012

Abstract. This paper reports the experience of a regional network of academic departments involved in water education that started as a project and evolved, over a period of 12 yr, into an independent network organisation. The paper pursues three objectives. First, it argues that it makes good sense to organise postgraduate education and research on water resources on a regional scale. This is because water has a transboundary dimension that poses delicate sharing questions, an approach that promotes a common understanding of what the real water-related issues are, results in future water specialists speaking a common (water) language, enhances mutual respect, and can thus be considered an investment in future peace. Second, it presents the WaterNet experience as an example that a regional approach can work and has an impact. Third, it draws three generalised lessons from the WaterNet experience. Lesson 1: For a regional capacity building network to be effective, it must have a legitimate ownership structure and a clear mandate. Lesson 2: Organising water-related training opportunities at a regional and transboundary scale makes sense – not only because knowledge resources are scattered, but also because the topic – water – has a regional and transboundary scope. Lesson 3: Jointly developing educational programmes by sharing expertise and resources requires intense intellectual management and sufficient financial means.
Green Certificates and Market Power on the Nordic Power Market
Authors: Amundsen Eirik S. , Bergman Lars
Published: March 2012

The purpose of this study is to elucidate under which circumstances, how, and to what extent market power on a Tradable Green Certificates (TGC) market can be used to affect an entire electricity market. There are basically two reasons for being concerned with this. One is that a small number of companies may have exclusive access to first rate sites for wind power generation. The other is that withdrawal of a small number of TGCs implies a multiple reduction of electricity consumption, with corresponding increases of end user prices. Wefor-mulate both an analytical model to investigate economic principles and a numerical model based on that to investigate the Swedish TGC market operating in a setting of a common Nordic electricity market. The analysis shows that Swedish producers may exercise market power using the TGC-market but that this problem will be eliminated by opening the TGC-market for other Nordic countries.
Spatial Risk Premium on Weather Derivatives and Hedging Weather Exposure in Electricity
Authors: Hrdle Wolfgang Karl , Osipenko Maria
Published: March 2012

Due to the dependency of the energy demand on temperature, weather derivatives enable the effective hedging of temperature related fluctuations. However, temperature varies in space and time and therefore the contingent weather derivatives also vary. The spatial derivative price distribution involves a risk premium. We employ a pricing model for temperature derivatives based on dynamics modeled via a vectorial Ornstein-Uhlenbeck process with seasonal variation. We use an analytical expression for the risk premia depending on variation curves of temperature in the measurement period. The dependence is exploited by a functional principal component analysis of the curves. We compute risk premia on cumulative average temperature futures for locations traded on CME and fit to it a geographically weighted regression on functional principal component scores. It allows us to predict risk premia for nontraded locations and to adopt, on this basis, a hedging strategy, which we illustrate in the example of Leipzig.
Inside the Black Box: the Price Linkage and Transmission between Energy and Agricultural Markets
Authors: Du Xiaodong , McPhail Lihong Lu
Published: March 2012

Motivated by strong comovement and increasing volatility of energy and agricultural prices, we examine dynamic evolutions of ethanol, gasoline, and corn prices over the period of March 2005-March 2011. A structural change is found around March 2008 in the pairwise dynamic correlations between the prices in a multivariate GARCH model. A structural VAR (SVAR) model is then estimated on two subsamples, one before and one after the identified change point. Using the novel method of identification through heteroscedasticity, we exploit the time-varying price volatilities to fully identify the SVAR model. In the more recent period, ethanol, gasoline, and corn prices are found to be more closely linked with a strengthened corn-ethanol relation, which can be explained by the new developments of the biofuel industry and related policy instruments. Variance decomposition shows that for each market a significant and relatively large share of the price variation could be explained by the price changes in the other two markets. The results are robust to the inclusion of seasonal dummies and various representative macroeconomic and financial indicators.
Emissions Trading in Forward and Spot Markets for Electricity
Authors: Tanaka Makoto , Chen Yihsu
Published: March 2012

Tradable allowances have received considerable attention in recent years. One emerging issue is their interaction with electricity markets. This paper extends the model of Allaz and Vila (1993) by incorporating emissions trading with forward and spot markets for electricity. We focus on the effects of strategic forward position and initial allowances allocation on the equilibrium outcomes. We find that firms with a dirty portfolio would have stronger incentives to take a long position in the forward market to raise the electricity price. Increasing the amount of allowances assigned to clean firms leads to a reduction in electricity and allowance prices.
Magnetic Electrospun Fibers for Cancer Therapy
Authors: Huang Chaobo , Soenen Stefaan J. , Rejman Joanna , Trekker Jesse , Chengxun Liu , Lagae Liesbet , Ceelen Wim , Wilhelm Claire , Demeester Jo , De Smedt Stefaan C.
Published: March 2012

Iron oxide nanoparticles (IONPs) for magnetic hyperthermia in cancer treatment have recently gained substantial interest. Unfortunately, the use of free IONPs still faces major challenges such as poor tumor targetability, high variability in the amount of IONPs taken up by the tumor and the IONP leakage from dead cancer cells into the surrounding healthy tissues. The present work reports on electrospun fiber webs, heavily loaded with 50 nm sized IONPs. The high loading capacity of the fibers enables significant heating of the environment upon applying an alternating magnetic field. Furthermore, magnetic fibers can be repeatedly heated without loss of heating capacity or release of IONPs. Upon functionalization of the fiber surface with collagen, human SKOV‐3 ovarian cancer cells attached well to the fibers. Applying an alternating magnetic field during 10 minutes to the fiber webs killed all fiber‐associated cancer cells. Killing the cells using this method seemed more efficient compared to the use of a warm water bath. As the fiber webs can be i) loaded with a well‐controlled amount of IONPs and ii) localized in the body by Magnetic Resonance Imaging, magnetic electrospun fibers may become promising materials for a highly reproducible (repeated) heating of cancer tissues in vivo.
A Self‐Doping, O2‐Stable, n‐Type Interfacial Layer for Organic Electronics
Authors: Reilly Thomas H. , Hains Alexander W. , Chen Hsiang‐Yu , Gregg Brian A.
Published: March 2012

Solid films of a water‐soluble dicationic perylene diimide salt, perylene bis(2‐ethyltrimethylammonium hydroxide imide), Petma+OH−, are strongly doped n‐type by dehydration and reversibly de‐doped by hydration. The hydrated films consist almost entirely of the neutral perylene diimide, PDI, while the dehydrated films contain ∼50% PDI anions. The conductivity increases by five orders of magnitude upon dehydration, probably limited by film roughness, while the work function decreases by 0.74 V, consistent with an n‐type doping density increase of ∼12 orders of magnitude. Remarkably, the PDI anions are stable in dry air up to 120 °C. The work function of the doped film, ϕ (3.96 V vs. vacuum), is unusually negative for an O2‐stable contact. Petma+OH− is also characterized as an interfacial layer, IFL, in two different types of organic photovoltaic cells. Results are comparable to state of the art cesium carbonate IFLs, but may improve if film morphology can be better controlled. The films are stable and reversible over many months in air and light. The mechanism of this unusual self‐doping process may involve the change in relative potentials of the ions in the film caused by their deshielding and compaction as water is removed, leading to charge transfer when dry.
Elaboration of controlled structure foams with the SMX static mixer
Authors: Talansier Emeline , Dellavalle Dominique , Loisel Catherine , Desrumaux Anne , Legrand Jack
Published: March 2012

A better control of the foaming process is important for food industry, as the structure of the liquid/gas mixture is a key parameter for the end‐used properties of foams. The main concern of this study is to present a methodology applicable to the parametric study of the foaming process that can help either to optimize the operating conditions or to adapt the formulation. We focused on the valorization of egg white proteins (EWPs). The method allows studying the effect of the process parameters on the foam structure and the effect of the thermal pretreatment of the EWP in the dry state on the rheology and the stability of foams. The foaming is achieved with a SMX10 static mixer, which allows the production of controlled structure foams. It is, therefore, possible to investigate the dependence of foam properties by comparing foams with the same alveolar structure in relation with their formulation. © 2012 American Institute of Chemical Engineers AIChE J, 59: 132–145, 2013
A novel nearly plug‐flow membrane bioreactor for enhanced biological nutrient removal
Authors: Meng Fangang , Zhou Zhongbo , Li Lei , Li Ruiyun , Jia Xiaoshan , Li Shiyu
Published: March 2012

The feasibility of enhanced biological nutrient removal by a new process called nearly plug‐flow membrane bioreactor (NPFMBR) is studied. Results of long‐term observations showed that average removal degrees of (1) chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) reached 95%, 85%, and 89%, respectively, at the steady operation period. Process success was further corroborated by batch experiments. Data of specific oxygen uptake rates demonstrated the abundance and/or high activities of ammonium oxidation bacteria and nitrite oxidation bacteria in the sludge. Observed specific rates of nitrification, denitrification, phosphorous release/uptake of the sludge were higher than those reported in previous research. Because of the unique flow pattern of sludge and alternant aerobic–anoxic operating conditions in the bioreactor, mass transfer and biotransformation of nutrients were expected to be improved. The NPFMBR could offer a new option for the wider application of MBRs. © 2012 American Institute of Chemical Engineers AIChE J, 59: 46–54, 2013
Thermische Wasserstoffabstraktion aus Methan – zur Rolle von Radikalen und Spinzuständen in der Chemie von Oxoclustern
Authors: Dietl Nicolas , Schlangen Maria , Schwarz Helmut
Published: March 2012

Die Übertragung eines Wasserstoffatoms (hydrogen‐atom transfer, HAT) ist als Prototyp einer chemischen Reaktion mit modernsten Methoden der Massenspektrometrie und der Computerchemie oft untersucht worden. Im Mittelpunkt dieses Kurzaufsatzes stehen die intrinsischen Eigenschaften von Oxoclustern in der Gasphase, durch die die Abstraktion eines Wasserstoffatoms aus gesättigten Kohlenwasserstoffen unter thermischen Bedingungen ermöglicht wird. Darüber hinaus werden mechanistische Erkenntnisse diskutiert, die für die heterogene Katalyse von Bedeutung sind. Aus experimentellen und rechnergestützter Studien folgt eindeutig, dass für HAT‐Prozesse in der Gasphase die am abstrahierenden Atom lokalisierte, ungepaarte Spindichte eine entscheidende Rolle spielt; diese Ergebnisse werden den Schlussfolgerungen für analoge Reaktionen in Lösung gegenübergestellt.
The effects of moderate‐intensity gradient static magnetic fields on nerve conduction
Authors: Okano Hideyuki , Ino Hiroyuki , Osawa Yu , Osuga Toshiaki , Tatsuoka Hozumi
Published: March 2012

Whether exposure to static magnetic fields (SMF) for medical applications poses a therapeutic benefit or a health hazard is at the focus of current debate. As a peripheral nerve model for studies of the SMF effects, we have investigated whether exposure of in vitro frog sciatic nerve fibers to moderate‐intensity gradient SMF up to 0.7 T modulates membrane excitation and refractory processes. We measured the changes in the amplitudes of the electrically evoked compound action potentials for three groups: a control group without SMF exposure and two exposed groups with continuous inhomogeneous exposure to maximum flux densities (Bmax) of 0.21 and 0.7 T SMF for 6 h. The values of the nerve conduction velocity of C fibers were significantly reduced by Bmax of 0.7 T SMF during the 4‐ to 6‐h exposure period but not by Bmax of 0.21 T SMF during the entire exposure period of 6 h, relative to the unexposed control. From these findings, we speculate that exposure to moderate‐intensity gradient SMF may attenuate pain perception because the C fibers are responsible for pain transmission. Although the mechanistic reasons for this decrease have yet to be clarified, SMF could affect the behavior of some types of ion channels associated with C fibers. Bioelectromagnetics 33:518–526, 2012. © 2012 Wiley Periodicals, Inc.
Vitamin E in aging, dementia, and Alzheimer's disease
Authors: Joshi Yash B. , Praticò Domenico
Published: March 2012

Since its discovery, vitamin E has been extensively researched by a large number of investigators in an attempt to fully understand its role in a variety of pathophysiological contexts. The vast majority of published work has focused on vitamin E's antioxidant properties, which is why it is well known as a lipophilic antioxidant that protects membranes from being oxidatively damaged by free radicals. However, several lines of investigation have recently revealed that vitamin E has biological roles unrelated to its antioxidant properties. Among these roles, vitamin E has been described as: a regulator of signal transduction, gene expression, and redox sensor. In parallel with the discovery of novels cellular functions of vitamin E, the introduction of the free radical theory of brain aging has propelled a renewed interest in this vitamin. Most of the resulting work has been based on the postulate that, by preventing and/or minimizing the oxidative stress‐dependent brain damage, vitamin E could be used as therapeutic approach. In this article, we will consider the existing literature regarding the biological properties of vitamin E and the potential therapeutic and/or preventative roles that this natural dietary factor plays in brain aging, cognition, and Alzheimer's dementia. © 2012 International Union of Biochemistry and Molecular Biology, Inc.
Rapid determination of yunaconitine and related alkaloids in aconites and aconite‐containing drugs by ultra high‐performance liquid chromatography–tandem mass spectrometry
Authors: Song Long , Zhang Hong , Liu Xin , Zhao Zhi‐Li , Chen Shi‐Lin , Wang Zheng‐Tao , Xu Hong‐Xi
Published: March 2012

Yunaconitine (YAC) is a toxic aconite alkaloid that is considered to be a hidden aconite poison since it is frequently found in body fluids from aconite poisoning patients, but has not been well studied in commonly used herbal drugs. In this paper, a rapid and sensitive ultra high‐performance liquid chromatography–tandem mass spectrometry (UHPLC‐MS/MS) detection combined with microwave‐assisted extraction (MAE) was developed for high throughput simultaneous determination of YAC and six other toxic aconite alkaloids in 31 samples of crude, processed aconites and aconite‐containing drugs. The optimized method showed excellent linearity, precision, accuracy and recovery for all target compounds with short run time. YAC was detected in some samples with contents from 0.015 to 10.41 mg/g. This is the first report on the determination of YAC in Radix Aconiti, Radix Aconiti Kusnezoffii and aconite‐containing drugs. This newly developed method facilitates the rapid screening of YAC and related toxic aconite alkaloids and allows YAC to be used as a chemical marker for the quality control of aconites and aconite‐containing drugs. Copyright © 2012 John Wiley & Sons, Ltd.
Teaching and learning computer science sorting algorithms with mobile devices: A case study
Authors: Boticki Ivica , Barisic Ante , Martin Sergio , Drljevic Neven
Published: March 2012

In this article, we present a semester‐long study on using smartphone devices in computing engineering education. We developed Sortko, an Android‐based smartphone application for learning sorting algorithms, an important undergraduate computer science topic. The application consists of four main components—the module for interactive sorting, the scaffolding module, the motivational module, and the graphical user interface module, each with a distinct role of helping students in learning sorting algorithms. Our research methodology included data collection with administered two surveys, collected exam results and recorded application usage data. Analysis of the collected data shows our approach is an effective way of learning sorting algorithms. © 2012 Wiley Periodicals, Inc. Comput Appl Eng Educ 21:E41–E50, 2013
Antifungal Activity of the Essential Oils of Callitris neocaledonica and C. sulcata Heartwood (Cupressaceae)
Authors: Waikedre Jean , Vitturo Carmen I. , Molina Ana , Theodoro Phellipe Norato Estrela Terra , do Rosário Rodrigues Silva Maria , Espindola Laila Salmen , Maciuk Alexandre , Fournet Alain
Published: March 2012

Mortality due to fungal infections has increased substantially, becoming a worldwide problem in public health. As a contribution to the discovery of new antifungal agents, the properties of the heartwood essential oils of two trees growing in New Caledonia, Callitris neocaledonica and C. sulcata (Cupressaceae) were investigated. The essential oils extracted by hydrodistillation were characterized by GC‐FID and GC/MS analyses. From C. neocaledonica oil, 31 constituents were identified, representing 97.0% of the total oil composition, which was mainly constituted by oxygenated sesquiterpenes (88%). Among them, guaiol (1; 30.2%), bulnesol (2; 12.5%), α‐eudesmol (3; 10.5%), β‐eudesmol (4; 10.5%), γ‐eudesmol (10.2%), and elemol (4.9%) predominated. The chemical composition of C. sulcata oil, from which 39 constituents were identified (96.8% of the total oil composition), showed some similarities with that of C. neocaledonica oil. The major constituents were also oxygenated sesquiterpenes, accounting for 78.5% of the oil, amongst them, mainly compounds 1 (16.1%), 3 and 4 (9.7% each), as well as 2 (7.4%). The antifungal activity of the oils against clinical isolates of four dermatophytic fungi (Trichophyton mentagrophytes, T. rubrum, Microsporum canis, and M. gypseum) and six yeasts (Candida albicans, C. parapsilosis, C. glabrata, C. krusei, Cryptococcus neoformans, and Cryptococcus gattii) was tested by determining minimum inhibitory concentrations (MICs) using the microdilution method. The best antifungal activities of the C. neocaledonica and C. sulcata oils were obtained against C. krusei (MICs of 3.9 and 0.975 μg/ml, resp.). These MIC values were similar to those of the reference drugs itraconazole and fluconazole (1.0 and 0.5 mg/ml, resp.). The oils were also subjected to a screening for their possible DPPH. (2,2‐diphenyl‐1‐picrylhydrazyl) radical‐scavenging activity. C. neocaledonica essential oil was more active than C. sulcata oil (93.3 vs. 32.2% DPPH. scavenged at 250 μg/ml).
Synthesis and Evaluation of 6‐Aza‐2′‐deoxyuridine Monophosphate Analogs as Inhibitors of Thymidylate Synthases, and as Substrates or Inhibitors of Thymidine Monophosphate Kinase in Mycobacterium tuberculosis
Authors: Kögler Martin , Busson Roger , De Jonghe Steven , Rozenski Jef , Van Belle Kristien , Louat Thierry , Munier‐Lehmann Hélène , Herdewijn Piet
Published: March 2012

A series of 5‐substituted analogs of 6‐aza‐2′‐deoxyuridine 5′‐monophosphate, 6‐aza‐dUMP, has been synthesized and evaluated as potential inhibitors of the two mycobacterial thymidylate synthases (i.e., a flavin‐dependent thymidylate synthase, ThyX, and a classical thymidylate synthase, ThyA). Replacement of C(6) of the natural substrate dUMP by a N‐atom in 6‐aza‐dUMP 1a led to a derivative with weak ThyX inhibitory activity (33% inhibition at 50 μM). Introduction of alkyl and aryl groups at C(5) of 1a resulted in complete loss of inhibitory activity, whereas the attachment of a 3‐(octanamido)prop‐1‐ynyl side chain in derivative 3 retained the weak level of mycobacterial ThyX inhibition (40% inhibition at 50 μM). None of the synthesized derivatives displayed any significant inhibitory activity against mycobacterial ThyA. The compounds have also been evaluated as potential inhibitors of mycobacterial thymidine monophosphate kinase (TMPKmt). None of the derivatives showed any significant TMPKmt inhibition. However, replacement of C(6) of the natural substrate (dTMP) by a N‐atom furnished 6‐aza‐dTMP (1b), which still was recognized as a substrate by TMPKmt.
Methods in Molecular Biology, Vol. 789: Neuropeptides: Methods and Protocols. Edited by Adalberto Merighi.
Authors: Saghatelian Alan
Published: March 2012

Humana Press, Totowa 2011, XI+416 pp., hardcover $ 139.00.—ISBN 978‐1‐61779‐309‐7
Enhanced stent imaging improves the diagnosis of stent underexpansion and optimizes stent deployment
Authors: Sanidas Elias A. , Maehara Akiko , Barkama Ravit , Mintz Gary S. , Singh Varinder , Hidalgo Ariel , Hakim Diaa , Leon Martin B. , Moses Jeffrey W. , Weisz Giora
Published: March 2012

Objectives

To investigate the clinical value and diagnostic accuracy of enhanced stent imaging (ESI) as compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).

Background

ESI is an image acquisition and processing angiography‐based software that improves visualization and provides measurements of deployed stents.

Methods

A total of 40 consecutive patients (42 stents) were studied. Stent deployment was evaluated sequentially and independently by angiography, ESI, and IVUS. Following each imaging modality, the operator determined the necessity of postdilation unrelated to the other modalities. Stent diameters were measured off‐line by QCA, ESI, and IVUS at several sites along the deployed stent and compared.

Results

Following stent deployment and based solely on angiography, the operator decided to postdilate seven of the 42 stents (16.7%). This decision was not changed after reviewing the ESI images of these seven stents. Of the 35 stents not requiring postdilation based on angiography alone, ESI influenced the operator to change the decision and postdilate 10 of 35 stents (28.6%). The ESI‐based measurements had better correlation with IVUS (r = 0.721, P < 0.0001) than did QCA with IVUS (r = 0.563, P < 0.0001). Bland‐Altman analysis showed a trend towards better agreement between ESI and IVUS than between QCA and IVUS (mean differences = 0.038 vs. 0.121; P = 0.19, respectively).

Conclusions

ESI is an easy to use modality that enhances stent visualization, helps in the decision making process whether to postdilate the stent, and provides estimation of stent expansion with better correlations than QCA when compared to IVUS. © 2012 Wiley Periodicals, Inc.
Current operator volumes of invasive coronary procedures in medicare patients: Implications for future manpower needs in the catheterization laboratory
Authors: Maroney Justin , Khan Saba , Powell Wayne , Klein Lloyd W.
Published: March 2012

Objectives

We seek to assess the per‐operator volume of diagnostic catheterizations and percutaneous coronary interventions (PCI) among US cardiologists, and its implication for future manpower needs in the catheterization laboratory.

Background

The number of annual Medicare PCIs peaked in 2004 and has trended downward since, however the total number of catheterization laboratories nationwide has increased. It is unknown whether these trends have resulted in a dilution of per‐operator volumes, and whether the current supply of interventional cardiologists is appropriate to meet future needs.

Methods

We analyzed the Centers for Medicare and Medicaid Services 2008 Medicare 5% sample file, and extracted the total number of Medicare fee‐for‐service (Medicare FFS) diagnostic catheterizations and PCIs performed in 2008. We then determined per‐physician procedure volumes using National Provider Identifier numbers.

Results

There were 1,198,610 Medicare FFS diagnostic catheterizations performed by 11,029 diagnostic cardiologists, and there were 378,372 Medicare FFS PCIs performed by 6,443 interventional cardiologists in 2008. The data reveal a marked difference in the 2008 distribution of diagnostic catheterizations and PCIs among operators. Just over 10% of diagnostic catheterizations were performed by operators performing 40 or fewer Medicare FFS diagnostic catheterizations, contrasted with almost 30% of PCIs performed by operators with 40 of fewer Medicare FFS PCIs. A significant majority of interventional cardiologists (61%) performed 40 or fewer Medicare FFS PCIs in 2008.

Conclusions

There is a high percentage of low‐volume operators performing PCI, raising questions regarding annual volume recommendations for procedural skill maintenance, and the future manpower requirements in the catheterization laboratory. © 2012 Wiley Periodicals, Inc.
Palliative stenting of patent ductus arteriosus in older children and young adults With congenital cyanotic heart disease
Authors: Francis Edwin , Kumar Shine , Kumar Raman Krishna
Published: March 2012

Objective

To describe the indications, technique and results (early and short‐term follow‐up) of palliative patent ductus arteriosus (PDA) stenting in selected patients (2 years and older) with congenital cyanotic heart disease with reduced pulmonary blood flow who were not candidates for definitive surgery in the immediate future.

Background

Stenting of PDA as a palliation has been advocated as safe and effective procedure in neonates, but this modality is underutilized for children and adults.

Methods

Hospital records of patients (≥2 years) undergoing PDA stenting between January 2007 and September 2009 were reviewed. The access and approach was dictated by the anatomy of the PDA. A coronary guiding catheter or a long sheath was used to access the PDA. Coronary or peripheral stents were used for stenting.

Results

Fifteen patients with median age 14 years (range: 2–18 years); median weight 17.5 kg (range: 7–57 Kg) were included. Indication for intervention was hypoxia (mean saturation 69% ± 8.9%, hemoglobin 19.8 ± 2.69 g/dl), unsuitable anatomy or economic considerations. Successful stenting was accomplished in all (mean fluoroscopy time of 24.6 ± 16.7 min) with no complications and the saturations improved to mean of 88% ± 2.3 %. The most recent oxygen saturations on follow‐up (median: 13 months; range: 1–21 months) were 82% ± 2.8%. One patient underwent corrective repair.

Conclusion

PDA stenting can provide effective palliation in selected older patients with cyanotic congenital heart disease. © 2013 Wiley Periodicals, Inc.
Charge‐Site‐Dependent Dissociation of Hydrogen‐Rich Radical Peptide Cations upon Vacuum UV Photoexcitation
Authors: Madsen James A. , Cheng Ryan R. , Kaoud Tamer S. , Dalby Kevin N. , Makarov Dmitrii E. , Brodbelt Jennifer S.
Published: March 2012

Here, 193 nm vacuum ultraviolet photodissociation (VUVPD) was used to investigate the fragmentation of hydrogen‐rich radical peptide cations generated by electron transfer reactions. VUVPD offers new insight into the factors that drive radical‐ and photon‐directed processes. The location of a basic Arg site influences photon‐activated CαC(O) bond cleavages of singly charged peptide radical cations, an outcome attributed to the initial conformation of the peptide as supported by molecular dynamics simulated annealing and the population of excited states upon UV excitation. This hybrid ETD/VUVPD method was employed to identify phosphorylation sites of the kinase domain of human TRPM7/ChaK1.
The General Phase Behavior of Mixtures of 1‐Alkyl‐3‐Methylimidazolium Bis[(trifluoromethyl)sulfonyl]amide Ionic Liquids with n‐Alkyl Alcohols
Authors: Vale Vlad R. , Will Stefan , Schröer Wolffram , Rathke Bernd
Published: March 2012

The liquid–liquid equilibrium (LLE) phase behavior of mixtures of 1‐ethyl‐3‐methylimidazolium bis[(trifluoromethyl)sulfonyl]amide (C2mimNTf2) with the n‐alkyl alcohols (CnOH; 3≤n≤8) is described. By applying the cloud‐point method, the LLEs were determined over a temperature range of 275–423 K at ambient pressure. Partial miscibility with upper critical solution temperatures (UCST) was observed. The UCST increase with increasing chain length of the alcohols. The phase diagrams were analyzed numerically by presuming Ising criticality. Concepts for the description of the asymmetry of the phase diagram by presuming the validity of the rectilinear diameter rule or a nonlinear diameter requested by the theory of complete scaling were applied. The results (UCST, critical composition, width and diameter of the phase diagrams) are compared with similar systems and discussed in terms of the corresponding state behavior; they map on a single curve. From at least 45 individual phase diagrams, general aspects of the behavior of this ionic liquid–alcohol mixture type were extracted. A simple empirical relationship was formulated to allow the description of the UCST with an accuracy of about 10 K when taking the ratio of the molar volumes of the alcohol and the 1‐alkyl‐3‐methylimidazolium cation of the ionic liquid into account.
Transgenic Xenopus laevis with the ef1‐α promoter as an experimental tool for amphibian retinal regeneration study
Authors: Ueda Yoko , Mizuno Nobuhiko , Araki Masasuke
Published: March 2012

Complete retinal regeneration occurs after the removal of the whole tissue in mature Xenopus laevis, as well as in the newt. Here, we produced F1 and F2 lines of transgenic X. laevis containing an EGFP gene under a translation elongation factor 1‐α (ef1‐α) promoter and investigated how the gene is reactivated in retinal pigmented epithelial (RPE) cells when the neural retina (NR) is removed. The results showed that EGFP expression is reduced in the adult ocular tissues of nonmanipulated transgenic animals, and EGFP‐expressing cells are occasionally found heterogeneously in the lens, NR and RPE tissues. During retinal regeneration, the EGFP gene is reactivated in the RPE and ciliary marginal cells. Transgenic animals were also used for a transplant study because of the genetic marker of the donor tissue. Transplanted RPE clearly transdifferentiated to regenerate the retina in the ocular chamber. This study is, to our knowledge, the first report of a transgenic study of amphibian retinal regeneration, and the approach is promising for future molecular analyses. genesis 50:642–650, 2012. © 2012 Wiley Periodicals, Inc.
Simple Tuning of the Optoelectronic Properties of IrIII and PtII Electrophosphors Based on Linkage Isomer Formation with a Naphthylthiazolyl Moiety
Authors: Xu Xianbin , Zhao Yongbiao , Dang Jingshuang , Yang Xiaolong , Zhou Guijiang , Ma Dongge , Wang Lixiang , Wong Wai‐Yeung , Wu Zhaoxin , Zhao Xiang
Published: March 2012

By tuning the substitution position of a thiazolyl group on the naphthalene system (α or β site), the distinctive electronic structures associated with these functional ligands have a substantial influence on both the photophysical behavior and electroluminescent (EL) performance of the resulting linkage isomers for two series of IrIII and PtII phosphorescent emitters. The photoluminescence wavelength can be redshifted by ca. 23 nm for the linkage isomers upon replacing the β‐substituted thiazolyl‐based ligand with its α‐substituted counterpart in the homoleptic series of IrIII phosphors. Furthermore, the bathochromic effect can be as much as ca. 42 nm for the heteroleptic IrIII phosphors and ca. 59 nm for the PtII compounds. Similarly, metallophosphors that bear β‐substituted ligands exhibit a different EL performance with respect to that of their linkage isomers with α‐substituted ligands. The best EL results associated with the triplet emitters chelated with β‐substituted ligands show a maximum brightness (Lmax) of 22563 cd m–2, an external quantum efficiency (ηext) of 12.88 %, a luminance efficiency (ηL) of 30.84 cd A–1, and a power efficiency (ηp) of 26.17 lm W–1, whereas the EL performance of their α‐counterparts was characterized by a peak Lmax of 8653 cd m–2, ηext of 6.18 %, ηL of 8.55 cd A–1, and ηp of 6.54 lm W–1. Owing to its unique electronic structure, the thiazolyl group is a good alternative to the pyridyl moiety to improve the EL performance of the metallophosphor. We have also demonstrated a simple and useful route to tune the functional properties of cyclometalated triplet emitters for EL applications.