bluuebunny/crossref_metadata_2025 huggingface dataset:
The Development and Maintenance of an "Evergreen" Spill Response Capability in the Gulf of Mexico
Authors: Hurzeler Kurt Lee , Scheuermann Roger
Published: April 2012

During the Macondo incident in 2011, over the course of 135 days BPmobilized the largest number of boats, planes, ROVs, specialized vessels, equipment and personnel ever used in a Gulf of Mexico emergency response. Therequirements to capture as much discharge as possible while minimizing theeffect of oil and other chemicals in the environment, in deep water withouttraditional well control options had stretched the technologies andcapabilities of the global industry. The methods applied, the equipment andpersonnel required, the procedures to be followed and the contingencies to bekept on hand were developed, applied and refined over the course of the Macondoresponse. In late June 2010 an industry task force was formed to begin activelyreviewing response options. As the Macondo well came under control in August2010, discussions of future response requirements were taking place within theindustry.

Two very different responses to the Macondo experience arose in the aftermath. On one hand, four large multinational companies committed substantial financialand personnel resources to a clear response based on Macondo. The proposedresponse system was defined, delivery dates were given and $1 billion USD wascommitted to the effort. The announcement was intended to reassure both thepublic and regulatory bodies that there would be a fix for any similar futureDeepwater Horizon Disaster. This group of four companies funded the formationof an LLC called the Marine Well Containment Company (MWCC).
UK Atlantic Margin Exploration: Its Petroleum Geology and Associated Technological Challenges
Authors: Quinn Martyn , Ritchie Derek , Gatliff Robert , Johnson Howard , Kimbell Geoff
Published: April 2012

The petroleum geology of UK Atlantic Margin presents a variety of technologicalchallenges for exploration of both established and new plays, developing newdiscoveries and maximising production in existing fields. The first explorationwell was drilled in the area in 1972 and over the next 40 years new plays havebeen developed and established plays re-visited. Exploration and developmenthas required new technological advances in order to push boundaries both interms of engineering in harsh environments and also geophysical tools to enablean understanding of the geology and fluids held within the rocks.

This paper focuses on the petroleum geology of the region and highlightstechnical challenges generated as a result of the geology and examples of howthese have been overcome by application of innovative techniques.

Under-explored areas in the Rockall region present opportunities, but withrisks and uncertainties related to hydrocarbon source, the presence ofreservoir and traps, which could be mitigated by a better geologicalunderstanding aided by improved seismic imaging, in particular sub-basaltimaging, and remote sensing technology. Further challenges exist related towater depth, the extreme weather conditions and the great distance to onshoreinstallations.

INTRODUCTION

The UK Atlantic Margin extends for nearly 2000 km from the Møre Basin in thenorth to the Rockall Basin in the south and forms part of a passive marginbounded to the west and north-west by oceanic crust of Cenozoic age (Figure 1). Oil exploration has taken place in the region for over 40 years but only asmall percentage of the UKCS blocks have been drilled. Exploration has focusedin the Faroe-Shetland Basin area with only a few wells drilled to the south inthe Rockall Basin. The area has three producing oil and natural gas fieldswhich, in terms of annual oil production, are in the ‘Top ten’ of UKhydrocarbon fields (Table 1). In addition, a large field development isunderway which is hoped will provide the infrastructure necessary to makeseveral undeveloped accumulations economically viable. Government estimates forundiscovered recoverable reserves west of Shetland range from a lower value ofaround 400 million barrels to a median of about 1 billion barrels and uppervalue of nearly 2 billion barrels of oil (DECC 2011(a)).

Water depth in the region varies from around 2400 m to less than 100 m onintra-basinal highs. Distances are great, with some prospective areas over 1000km from shore-based facilities. The harsh environment with strong currents andoften severe weather is an immense challenge to conducting safe and efficientoperations. Exploration and development has stimulated technological innovationand success in the latter has enabled exploration and development toprogress.
Geohazards and Ocean Hazards in Deepwater: Overview and Methods of Assessment
Authors: Stow Dorrik , Brackenridge Rachel , Patel Urval , Toulmin Suzannah
Published: April 2012

Drilling for hydrocarbons in the deep marine environment provides a unique setof challenges for industry. Amongst these are the distinct hazards caused bynatural geological and oceanic processes such as:semi-permanent bottomcurrents,episodic turbidity currents, slope instability and mass transportevents (slides, slumps, debris flows), andgas hydrate escape. We presentdata on the nature, effects and assessment of these deepwater hazards, including current velocities, transport/erosion capacities, recurrenceintervals, and hydrate distribution. It is of upmost importance that theoceanographic conditions are carefully considered prior to deepwater operationsto ensure the work can be carried out safely. Thorough risk assessment requiresknowledge of existing bottom currents, an assessment of potential masstransport events and turbidity currents, and understanding of conditions likelyto induce the formation and destabilisation of gas hydrates. Pipelines, cables, subsea installations, key connections such as the riser and any other seabedinfrastructure are all susceptible to damage. Correct assessment of hazard willallow for the right equipment to be used for the operations including blowoutpreventers, riser size, vibration suppressors, and for the safest siting ofcables and pipelines. It will also aid the subsea architecture design andplanning operations with minimal downtime. All these considerations lead to asafer exploration and production while eliminating unnecessary cost.

Introduction

Deepwater is defined by different communities in slightly different ways. Forthe marine geologist and oceanographer, it is often taken as that area of theocean beyond the shelf break, i.e. deeper than about 100–200 m water depth. Forthe sedimentologist, it is below storm wave base, which is also around 100–200m. For the industry, deepwater exploration is considered to be that in waterdepths in excess of 500 m. For the purposes of this paper, we consider theshelf-slope transition (i.e. shelf break) as the key boundary between shallowand deep water.

This deepwater environment is far from tranquil. It is subject to a range ofprocesses that will significantly affect drilling operations for hydrocarbonexploration and recovery. Bottom currents are everywhere present and in someareas they are especially active and with considerably elevated velocities. Here we first focus on deepwater bottom currents and the hazards they present. Their occurrence and distribution, nature and variability, and damage potentialare discussed, followed by consideration of the methods of hazard assessment. We present a new method using the bedform-velocity matrix.
High-resolution FWI: Changing the Way we Image and Interpret Seismic
Authors: Lazaratos Spyros , McAdow David Douglas , Routh Partha S. , Chikichev Ivan
Published: April 2012

The emergence of Full Wavefield Inversion (FWI) methods represents a paradigmshift with the potential to revolutionize the way we image and interpretseismic. Advances in algorithms and computing technology are now making FWIpractical, making it possible to construct detailed subsurface property modelsthat adequately explain the full bandwidth of the seismic data. We recentlydeveloped new concepts and algorithms that allow us to run 3D FWI using muchhigher frequencies - up to 45 Hz for one of the examples we will be discussing- than what has been shown in most published FWI studies to-date (usually lessthan 8–10 Hz). High-resolution FWI products can be viewed as 3D volumes of welllogs, and their availability creates new opportunities in the way we interpretand use seismic data. We expect FWI to impact applications at all businessstages, ranging from improved structural imaging during exploration to detailedreservoir description and characterization for development andproduction.

Introduction

Seismic imaging has been advancing rapidly over the last two decades, transitioning from post-stack time migration to pre-stack depth migration andfrom ray-theoretic algorithms (Kirchoff migration) to one-way wave-equationsolvers (wave-equation migration), and finally to more accurate reverse-timemigration (RTM) methods. This progression has been motivated by the businessclimate, with exploration moving to more and more challenging environments(e.g. Gulf of Mexico sub-salt) and the demand for more and more accuratereservoir characterization to maximize and maintain production from discoveredfields. The most recent, and perhaps ultimate, step in this evolving sequenceis Full Wavefield Inversion (FWI), which has rapidly become a focal area forresearch and development within the geophysical community and industry. Onecould argue that the FWI approach represents the dream of every geoscientist:generate detailed subsurface property models of the earth that can accuratelyreproduce, through simulation, the seismic data used to construct them. Unlikeevolution in the migration algorithms, which has been continuous andincremental, FWI represents a change in philosophy, both in the way we imagethe seismic data, and also in how we interpret the resulting products.

Although much more research and development will be necessary to capitalize onthe full potential of FWI, we feel that several of the main difficulties(primarily overcoming the computational requirements necessary to implement andapply the method) have been overcome. We are already using FWI to generatesubsurface models with the resolution and quality to impact business decisions. This presentation will provide an overview of the method, some of the advancesthat are making it feasible, and real data examples to illustrate itspotential.
A Case of Retropharyngeal Abscess with Spondylitis Causing Tetraplegia
Authors: Kusunoki Takeshi , Ito Shin , Iizuka Takashi , Ono Noritsugu , Ikeda Katsuhisa
Published: April 2012

We report a case of retropharyngeal abscess with spondylitis causing tetraplegia. At a previous hospital, administration of antibiotics improved the inflammation findings. However, magnetic resonace imaging showed a remaining retropharyngeal abscess. This patient showed a disturbance of consciousness under this therapy. Therefore, he was admitted to our hospital and underwent a drainage operation. At 1 day after this operation, he recovered from the disturbance of consciousness.
Efficient Feature Selection and Multiclass Classification with Integrated Instance and Model Based Learning
Authors: Liu Zhenqiu , Bensmail Halima , Tan Ming
Published: April 2012

Multiclass classification and feature (variable) selections are commonly encountered in many biological and medical applications. However, extending binary classification approaches to multiclass problems is not trivial. Instance-based methods such as the K nearest neighbor (KNN) can naturally extend to multiclass problems and usually perform well with unbalanced data, but suffer from the curse of dimensionality. Their performance is degraded when applied to high dimensional data. On the other hand, model-based methods such as logistic regression require the decomposition of the multiclass problem into several binary problems with one-vs.-one or one-vs.-rest schemes. Even though they can be applied to high dimensional data with L1 or L p penalized methods, such approaches can only select independent features and the features selected with different binary problems are usually different. They also produce unbalanced classification problems with one vs. the rest scheme even if the original multiclass problem is balanced.

By combining instance-based and model-based learning, we propose an efficient learning method with integrated KNN and constrained logistic regression (KNNLog) for simultaneous multiclass classification and feature selection. Our proposed method simultaneously minimizes the intra-class distance and maximizes the interclass distance with fewer estimated parameters. It is very efficient for problems with small sample size and unbalanced classes, a case common in many real applications. In addition, our model-based feature selection methods can identify highly correlated features simultaneously avoiding the multiplicity problem due to multiple tests. The proposed method is evaluated with simulation and real data including one unbalanced microRNA dataset for leukemia and one multi-class metagenomic dataset from the Human Microbiome Project (HMP). It performs well with limited computational experiments.
Mobile Phone Electromagnetic Waves and Its Effect on Human Ejaculated Semen: An in vitro Study
Authors: Vasan SS , Veerachari Srinivas Belur
Published: April 2012

Mobile phones usage has seen an exponential growth recently. With this increasing demand, the amount of electromagnetic radiation (EMR) exposed is also increasing. Hence, we studied the effect of these radiations on ejaculated human semen and speculate the contribution of these harmful radiations in male infertility. Samples exposed to EMR showed a significant decrease in sperm motility and viability, increase in reactive oxygen species (ROS) and DNA fragmentation index (DFI) compared to unexposed group. We concluded that mobile phones emit electromagnetic waves which lead to oxidative stress in human semen and also cause changes in DNA fragmentation. We extrapolate these findings to speculate that these radiations may negatively affect spermatozoa and impair male fertility.

How to cite this article

Veerachari SB, Vasan SS. Mobile Phone Electromagnetic Waves and Its Effect on Human Ejaculated Semen: An in vitro Study. Int J Infertility Fetal Med 2012;3(1):15-21.
Enhancing user involvement with digital cultural heritage: The usage of social tagging and storytelling
Authors: Vliet Harry van , Hekman Erik
Published: April 2012

This paper focuses on the use of online social tagging and storytelling to enrich digital collections of cultural heritage. Together with several Dutch museums, we examined the question of whether and how social tagging could benefit these museums in disclosing specific digital collections. This led to the development of a social tagging tool (www.ikweetwatditis.nl) as a means of researching behaviour when tagging cultural objects. The results show that tagging and storytelling can help museums enrich their collections and involve their audiences.
Tourism Yield of Different Market Segments: A Case Study of Hawaii
Authors: Pratt Stephen
Published: April 2012

This paper estimates the economy-wide economic impacts of tourism for various market segments. Moving beyond volume (arrivals) versus value (direct tourism expenditure), the author examines various economy-wide measures of economic impact. Different visitor spending has different flow-on effects, depending on each sector's taxation rate, import quotient and capital–labour ratio. It is important for destination marketing organizations and tourism policy makers to factor in these characteristics when considering the full economic impact of tourism expenditure.
Investments in Ski Areas: Effects of Compensation Payments in a Complementary Value Network
Authors: Lohmann Christian , Crasselt Nils
Published: April 2012

This study focuses on a complementary value network consisting of a snow sports company operating in a ski resort and accommodation businesses located in that resort. If the snow sports company increases the resort's attractiveness by investing in new infrastructure, such as ski lifts or snowmaking facilities, its investment has positive external effects on the revenue of local accommodation businesses. If the cost of these external effects is not compensated by the accommodation businesses, this situation typically creates an underinvestment problem at the expense of the snow sports company. In this context, the authors analyse the extent to which revenue-based and quantity-based compensation payments can mitigate the problem. First, they identify conditions under which such payments increase the profits of both the snow sports company and the accommodation businesses. They further show that a revenue-based compensation payment dominates a quantity-based compensation payment with respect to company profit maximization, because it distorts neither the price nor the quantity decisions of the accommodation businesses.
The Autoimmune Model of Schizophrenia
Authors: Adams D. D. , Knight J. G. , Ebringer A.
Published: April 2012

Schizophrenia is of mysterious causation. It is not infectious, not congenital, but shows familial aggregation, the Mendelian genetics indicating involvement of multiple codominant genes with incomplete penetrance. This is the pattern for autoimmune diseases, such as Graves’ disease of the thyroid, where forbidden clones of B lymphocytes develop, and cause thyrotoxicosis by secreting autoantibodies that react with the thyroid gland’s receptor for thyroid-stimulating hormone from the pituitary gland. In 1982, Knight postulated that autoantibodies affecting the function of neurons in the limbic region of the brain are a possible cause of schizophrenia. Today, this is even more probable, with genes predisposing to schizophrenia having being found to be immune response genes, one in the MHC and two for antibody light chain V genes. Immune response genes govern the immune repertoire, dictating the genetic risk of autoimmune diseases. The simplest test for an autoimmune basis of schizophrenia would be trial of immunosuppression with prednisone in acute cases. The urgent research need is to find the microbial trigger, as done by Ebringer for rheumatoid arthritis and for ankylosing spondylitis. This could lead to prophylaxis of schizophrenia by vaccination against the triggering microbe.
Obstacles to Addressing Race and Ethnicity in the Mathematics Education Literature
Authors: Parks Amy Noelle , Schmeichel Mardi
Published: April 2012

This Research Commentary builds on a 2-stage literature review to argue that there are 4 obstacles to making a sociopolitical turn in mathematics education that would allow researchers to talk about race and ethnicity in ways that take both identity and power seriously: (a) the marginalization of discussions of race and ethnicity; (b) the reiteration of race and ethnicity as independent variables; (c) absence of race and ethnicity from mathematics education research; and (d) the minimizing of discussions of race and ethnicity, even within equity-oriented work.
Conjugated Polymer Based Nanoparticles as Dual‐Modal Probes for Targeted In Vivo Fluorescence and Magnetic Resonance Imaging
Authors: Li Kai , Ding Dan , Huo Da , Pu Kan‐Yi , Thao Ngo Nguyen Phuong , Hu Yong , Li Zhi , Liu Bin
Published: April 2012

A facile strategy is developed to synthesize dual‐modal fluorescent‐magnetic nanoparticles (NPs) with surface folic acid by co‐encapsulation of a far‐red/near‐infrared (FR/NIR)‐emissive conjugated polymer (PFVBT) and lipid‐coated iron oxides (IOs) into a mixture of poly(lactic‐co‐glycolic‐acid)‐poly(ethylene glycol)‐folate (PLGA‐PEG‐FOL) and PLGA. The obtained NPs exhibit superparamagnetic properties and high fluorescence, which indicates that the lipid coated on IOs is effective at separating the conjugated polymer from IOs to minimize fluorescence quenching. These NPs are spherical in shape with an average diameter of ≈180 nm in water, as determined by laser light scattering. In vitro studies reveal that these dual‐modal NPs can serve as an effective fluorescent probe to achieve targeted imaging of MCF‐7 breast cancer cells without obvious cytotoxicity. In vivo fluorescence and magnetic resonance imaging results suggest that the NPs are able to preferentially accumulate in tumor tissues to allow dual‐modal detection of tumors in a living body. This demonstrates the potential of conjugated polymer based dual‐modal nanoprobes for versatile in vitro and in vivo applications in future.
Highly Concentrated and Conductive Reduced Graphene Oxide Nanosheets by Monovalent Cation–π Interaction: Toward Printed Electronics
Authors: Jeong Seung Yol , Kim Sung Hun , Han Joong Tark , Jeong Hee Jin , Jeong Soo Yeon , Lee Geon‐Woong
Published: April 2012

A novel route to preparing highly concentrated and conductive reduced graphene oxide (RGO) in various solvents by monovalent cation–π interaction. Previously, the hydrophobic properties of high‐quality RGO containing few defects and oxygen moieties have precluded the formation of stable dispersion in various solvents. Cation–π interaction between monovalent cations, such as Na+ or K+, and six‐membered sp2 carbons on graphene were achieved by simple aging process of graphene oxide (GO) nanosheets dispersed in alkali solvent. The noncovalent binding forces introduced by the cation–π interactions were evident from the chemical shift of the sp2 peak in the solid 13C NMR spectra. Raman spectra and the I‐V characteristics demonstrated the interactions in terms of the presence of n‐type doping effect due to the adsorption of cations with high electron mobility (39 cm2/Vs). The RGO film prepared without a post‐annealing process displayed superior electrical conductivity of 97,500 S/m at a thickness of 1.7 μm. Moreover, mass production of GO paste with a concentration as high as 20 g/L was achieved by accelerating the cation–π interactions with densification process. This strategy can facilitate the development of large scalable production methods for preparing printed electronics made from high‐quality RGO nanosheets.
Online conductivity and stability in the emulsion polymerization of N‐butyl methacrylate: Nonreactive versus reactive systems
Authors: Zhao Funian , Sudol E. David , Daniels Eric S. , Klein Andrew , El‐Aasser Mohamed S.
Published: April 2012

Two different types of conductivity probes, that is, a torroidal probe and a resistance probe, were used as online sensors to monitor conductivity during the course of emulsion polymerizations of n‐butyl methacrylate (BMA). These measurements were first applied to a nonreactive system, but the results showed that this method cannot be used to monitor latex stability in this system. Batch emulsion polymerizations of BMA were then carried out using different concentrations (0.6, 1.2, 2.4, and 7.8 mM) of sodium lauryl sulfate (SLS) as surfactant. The profiles of the two conductivity curves changed with the variation of the SLS concentration. Because deposition of polymers on the surfaces of the electrodes of the resistance probe can reduce the measured conductivity values obtained from this probe (R) such that they are lower than the true values, as measured by the torroidal probe (T), the final conductivity ratio (R/T) between the two conductivity curves was chosen as a parameter to correlate the conductivity measurements to latex stability, which was estimated using blender tests and turbidity measurements. A linear relationship between them was found, indicating that the online conductivity measurements could be used to predict latex stability in the BMA emulsion polymerization system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of core–shell nanoparticle‐based hindered amine stabilizer and its application in polyoxymethylene
Authors: You Bin , Zhou Daojun , Zhang Shiling , Yang Fan , Ren Xiancheng
Published: April 2012

Core–shell nanoparticles chemically functionalized by hindered amine stabilizer (HAS), poly(BA‐MMA‐co‐PMPA) (PBMP), were prepared by two‐stage emulsion polymerization from butyl acrylate, methyl methacrylate, and 1,2,2,6,6‐pentamethylpiperidin‐4‐yl acrylate. The incorporation of HAS into the particles was confirmed by nuclear magnetic resonance (1H‐NMR) and the core–shell microstructure of PBMP particles was revealed by transmission electron microscopy. Furthermore, PBMP capable of one‐step toughening and photostabilizing, was melt‐blended with polyoxymethylene (POM), and its dispersion in POM was investigated by scanning electron microscope. The results showed that the core–shell nanoparticles could be well dispersed in POM matrix, indicating its good compatibility with POM. The UV resistance and impact resistance of POM were obviously improved by the HAS‐functional core–shell nanoparticles simultaneously. In addition, the core–shell nanoparticles could confer excellent protection to the surface of POM from UV‐light damage, regardless of the adverse effects on the thermal‐oxidative stability of POM, as investigated by thermogravimetry analysis under aerobic condition. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A nonenzymatic hydrogen peroxide sensor based on Pt/PPy hollow hybrid microspheres
Authors: Li Yulin , Chang Yunzhen , Jin Ming , Liu Yanyun , Han Gaoyi
Published: April 2012

The surface of silica particles was NH2 functionalized by 3‐aminopropyltrimethoxysilane, then the platinum/polypyrrole hybrid hollow microspheres were prepared by treating the SiO2 template decorated by the H2PtCl6 via the NH2 group with pyrrole vapor and developed as hydrogen peroxide (H2O2) sensor. The platinum/polypyrrole hybrid hollow sphere materials were characterized by transmission electron microscopy and infrared spectroscopy, and the catalytic electrodes were investigated by electrochemical method. The results showed that the nonenzymatic sensor displayed a good electro‐catalytic response and high sensitivity to the oxidation of H2O2, and the resulting sensor showed a wide linear range from 1.9 to 9.7 mM H2O2. The obvious response could be still observed in i–t curve when the concentration of H2O2 was as low as 1.0 μM. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis, cure and pyrolysis behavior of heat‐resistant boron‐silicon hybrid polymer containing acetylene
Authors: Chen MingFeng , Zhou Quan , Ni LiZhong , Wang GengChao
Published: April 2012

The synthesis and characterization of a novel heat‐resistant boron‐silicon hybrid polymer containing acetylene (PBSA) and its conversion to a highly crosslinked thermoset were discussed. The polymer was synthesized from phenylboron dichloride using Grignard reagent method. The structure of PBSA was characterized by using Fourier transform infrared spectra, 1H‐NMR, 13C‐NMR, and gel permeation chromatography. PBSA was thermosetting, highly heat‐resistant, high‐viscous, orange liquid at room temperature and good solubility in common organic solvents. Differential scanning calorimetry and thermogravimetric analysis analyses showed that the PBSA had excellent thermal and oxidative stability and the temperature of 5% weight loss (Td5) were 650 and 638°C under nitrogen and air, respectively, and the residue at 1000°C were 93.3 and 91.3%, respectively, which indicated that the incorporation of boron and silicon into polymeric backbone was found to improve thermal and oxidative properties. X‐ray diffraction and scanning electron microscope were also used to analyze the formation of pyrolytic products. The results showed that the pyrolysis of PBSA resin was made up of β‐SiC and graphite. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synergistic effect of ammonium polyphosphate and expandable graphite on flame‐retardant properties of acrylonitrile‐butadiene‐styrene
Authors: Ge Lan‐Lan , Duan Hong‐Ji , Zhang Xiao‐Guang , Chen Chen , Tang Jian‐Hua , Li Zhong‐Ming
Published: April 2012

A new intumescent flame‐retardant (IFR) system consisting of expandable graphite (EG) and ammonium polyphosphate (APP) was applied in acrylonitrile–butadiene–styrene (ABS) resin. A synergistic effect between EG and APP on the flame retardancy of ABS was observed. Fixing the total loading of flame retardant at 15 wt %, the limited oxygen index (LOI) could reach 31 vol % at a weight ratio of 3 : 1 for EG and APP. While LOI values of EG‐ and APP‐filled ABS were only 26.0 and 21.5 vol % at the same loading, respectively. The UL‐94 vertical burning test suggested that samples with different ratios of EG and APP could all pass V‐0 rating while the samples containing EG and APP alone only passed V‐1 rating. Thermogravimetric analysis indicated that the addition of EG and APP (3 : 1 by weight) to ABS led to an increase in the amount of high‐temperature residue by 11.8 wt %, and a decrease of mass loss rate by 0.7%/°C compared with pure ABS. Scanning electronic microscopy revealed a homogeneous compact intumescent char layer of ABS/EG/APP samples. Based on our experiment and combined with others' previous studies, the synergistic mechanism is inferred. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Fluorescence quenching method for the determination of carbazochrome sodium sulfonate with aromatic amino acids
Authors: Gan Xiao‐Juan , Liu Shao‐Pu , Liu Zhong‐Fang , Hu Xiao‐Li , Tian Jing , Xue Jia‐Xing
Published: April 2012

In Britton‐Robinson (BR) buffer medium (pH 3.3), carbazochrome sodium sulfonate (CSS) can react with some aromatic amino acids such as tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe) to form a 1:1 complex by electrostatic attraction, aromatic stacking interaction and Van der Waals' force, resulting in fluorescence quenching of these amino acids. Maximum quenching wavelengths were located at 352 nm (CSS‐Trp system), 303 nm (CSS‐Tyr system) and 284 nm (CSS‐Phe system), respectively. The fluorescence quenching value (ΔF) was proportional to the concentration of CSS in a certain range. The fluorescence quenching method for the determination of CSS showed high sensitivity, with detection limits of 31.3 ng/mL (CSS‐Trp system), 44.6 ng/mL (CSS‐Tyr system) and 315.0 ng/mL (CSS‐Phe system), respectively. The optimum conditions of the reaction conditions and the effect of coexisting substances were investigated and results showed that the method had good selectivity. The method was successfully applied for the rapid determination of CSS in blood and urine samples. Based on the bimolecular quenching constant Kq, the effect of temperature and Stern‐Volmer plots, this study showed that quenching of fluorescence of amino acids by CSS was a static quenching process. Copyright © 2012 John Wiley & Sons, Ltd.
Enantioselective toxicological response of the green alga Scenedesmus obliquus to isocarbophos
Authors: Lu Dahai , Huang Ledan , Diao Jinling , Zhou Zhiqiang
Published: April 2012

Chiral compounds usually behave enantioselectively in phyto‐biochemical processes. Isocarbophos (ICP) is a chiral pesticide that is widely used. To evaluate the toxicological response of ICP and its enantiomers to Scenedesmus obliquus, algal growth, total chlorophyll, total soluble protein, and the superoxide anion radicals (O2•‐) were investigated. The microalgae were treated with ICP and its enantiomers at 0.01–10 mg/l for 96 h. The growth of S. obliquus was stimulated at low levels of ICP and its enantiomers (0.01–1 mg/l), but all were inhibited at high concentrations (10 mg/l). The total soluble protein content and total chlorophyll content of the tested green alga S. obliquus gradually increased, depending on the growth of algal cells in the medium. Meanwhile, the content of O2•‐ was decreased. Interestingly, the cell number and content of the chlorophylls and protein decreased with increasing levels of concentration, whereas O2•‐ increased. Our results indicated that enantioselectivity was observed in the dose–response of ICP and its enantiomers in S. obliquus. The high O2•‐ level might lead to the death of S. obliquus. The stimulation of growth suggests a regulatory mechanism that is related to the capability of the algae to adapt to the O2•‐. Chirality 24:481–485, 2012. © 2012 Wiley Periodicals, Inc.
Analysis of Chirality by Femtosecond Laser Ionization Mass Spectrometry
Authors: Horsch Philipp , Urbasch Gunter , Weitzel Karl‐Michael
Published: April 2012

Recent progress in the field of chirality analysis employing laser ionization mass spectrometry is reviewed. Emphasis is given to femtosecond (fs) laser ionization work from the author's group. We begin by reviewing fundamental aspects of determining circular dichroism (CD) in fs‐laser ionization mass spectrometry (fs‐LIMS) discussing an example from the literature (resonant fs‐LIMS of 3‐methylcyclopentanone). Second, we present new data indicating CD in non‐resonant fs‐LIMS of propylene oxide.Chirality 24:684–690, 2012. © 2012 Wiley Periodicals, Inc.
Conformational Flexibility and Absolute Stereochemistry of (3R)‐3‐hydroxy‐4‐aryl‐β‐lactams Investigated by Chiroptical Properties and TD‐DFT Calculations
Authors: Tedesco Daniele , Zanasi Riccardo , Guerrini Andrea , Bertucci Carlo
Published: April 2012

The effect of conformational flexibility on the chiroptical properties of a series of synthetic (3R)‐3‐hydroxy‐4‐aryl‐β‐lactams of known stereochemistry (1–6) was investigated by means of electronic circular dichroism (ECD) measurements and time‐dependent density functional theory (TD‐DFT) calculations. The application of the β‐lactam sector rules allowed a correct stereochemical characterization of these compounds, with the exception of a thienyl‐substituted derivative (cis‐6). TD‐DFT calculations yielded accurate predictions of experimental ECD spectra and [α]D values, allowing us to assign the correct absolute configuration to all the investigated compounds. A detailed analysis of the β‐lactam ring equilibrium geometry on optimized conformers identified regular patterns for the arrangement of atoms around the amide chromophore, confirming the validity of the β‐lactam sector rules. However, relevant variations in theoretical chiroptical properties were found for compounds bearing a heterocyclic substituent at C4 or a phenyl substituent at C3, whose conformers deviate from these regular geometric patterns. This behavior explains the failure of the β‐lactam sector rules in cis‐6. This study showed the importance of conformational flexibility for the determination of chiroptical properties and highlighted the strengths and weaknesses of the different methods for the stereochemical characterization of chiral molecules in solution. Chirality 24:741‐750, 2012. © 2012 Wiley Periodicals, Inc.
Fine‐scale parallel patterns in diversity of small benthic Arctic charr (Salvelinus alpinus) in relation to the ecology of lava/groundwater habitats
Authors: Kristjánsson Bjarni K. , Skúlason Skúli , Snorrason Sigurður S. , Noakes David L.G.
Published: April 2012

It is critical to study factors that are important for origin and maintenance of biological diversity. A comparative approach involving a large number of populations is particularly useful. We use this approach to study the relationship between ecological factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus). Numerous populations of small benthic charr have evolved in lava springs in Iceland. These charr appear morphologically similar, but differ in important morphological features related to feeding. We found a clear relationship between diversity in morphology, diet, and ecological factors among populations. In particular, there were clear differences in morphology and diet between fish coming from habitats where the lava spring flowed on as a stream compared to habitats where the lava spring flowed into a pond. Our study shows that ecological factors are important for the origin and maintenance of biological diversity. The relationship between phenotype and ecological factors are observed on a fine scale, when comparing numerous populations that are phenotypically similar. This strongly suggests that for understanding, managing, and conserving biological diversity important ecological variables have to be taken into the account.
HOW MANY INFANTS LIKELY DIED IN AFRICA AS A RESULT OF THE 2008–2009 GLOBAL FINANCIAL CRISIS?
Authors: Friedman Jed , Schady Norbert
Published: April 2012

The human consequences of the recent global financial crisis for the developing world are presumed to be severe, but few studies have quantified them. This letter estimates the human cost of the 2008–2009 global financial crisis in one critical dimension—infant mortality—for countries in sub‐Saharan Africa. The analysis pools birth‐level data, as reported in female adult retrospective birth histories from all Demographic and Health Surveys collected in sub‐Saharan Africa. This results in a data set of 639,000 births to 264,000 women in 30 countries. We use regression models with flexible controls for temporal trends to assess an infant's likelihood of death as a function of fluctuations in national income. We then calculate the expected number of excess deaths by combining these estimates with growth shortfalls as a result of the crisis. The results suggest 28,000–50,000 excess infant deaths in sub‐Saharan Africa in the crisis‐affected year of 2009. Notably, most of these additional deaths were concentrated among girls. Policies that protect the income of poor households and that maintain critical health services during times of economic contraction may reduce the expected increase in mortality. Interventions targeted at female infants and young girls can be particularly beneficial. Copyright © 2012 John Wiley & Sons, Ltd.
ON THE ROLE OF THE TROPICS IN THE GENERAL CIRCULATION OF THE ATMOSPHERE
Authors: Riehl Herbert
Published: April 2012

Present knowledge on the role of the tropics in the general circulation is reviewed in comparison with our knowledge twenty years ago. Increasing amounts of upper‐air data in the tropics since that time plus the advent of rawin measurements have placed many calculations of the mean seasonal exchange of heat, moisture and angular momentum between the tropics and the extratropical regions on a fairly firm basis. The large troughs seen extending from higher latitudes to the heart of the tropics even with late World War II observations have been confirmed in their role as the principal exchange mechanism. On the other hand, the mean meridional circulation can account for the upward transport of angular momentum which is generated with easterlies within the tropics and also for the net generation of kinetic energy south of 30°N. About 50 per cent of the kinetic energy required north of 30°N in winter to maintain the circulation against frictional dissipation, is imported from the tropics by means of the standing waves of the subtropical jet‐stream. Hence it is clear that the tropics help to sustain the kinetic energy of the westerlies and that the tropical circulation is not driven from higher latitudes as often claimed.

The sense of total energy transport by the mean meridional circulation inside the tropics is not easily calculated and may even reverse sign. Complications on total energy export also have arisen through the nimbus ii albedo observations which have shown lower albedo (less cloudiness), hence also a larger energy source, for the tropics than previously estimated. It appears certain, merely, that the equatorial trough migrates seasonally so that energy very likely does not pass through it, hence that it constitutes a true “meteorological equator”. No evidence concerning important coupling between the hemispheres across the equator has come to light; however, the new data systems of the next decade may well alter this conclusion.

Because of the sensitive computational situation concerning energy transport by the mean meridional circulation, it may be that successful operational application of cloud seeding techniques, such as demonstrated in Project Stormfury in the Caribbean, could exert a subtle influence on the general circulation. This apart, the present status of observational networks is judged to be so far advanced that fluctuations of quantities such as the mean meridional circulation within a season, and in the same month from year to year, can shortly be calculated, possibly shedding light on the variability of the general circulation and precipitation excesses and deficits in tropical regions.
Direct Electrochemistry of Glucose Oxidase Immobilized on Titanium Carbide‐Au Nanoparticles‐Fullerene C60 Composite Film and Its Biosensing for Glucose
Authors: Wang Minzhi , Zheng Jianbin , Wang Lu , Dong Sheying
Published: April 2012

The direct electrochemistry of glucose oxidase (GOD) immobilized on the designed titanium carbide‐Au nanoparticles‐fullerene C60 composite film modified glassy carbon electrode (TiC‐AuNPs‐C60/GCE) and its biosensing for glucose were investigated. UV‐visible and Fourier‐transform infrared spectra of the resulting GOD/TiC‐AuNPs‐C60 composite film suggested that the immobilized GOD retained its original structure. The direct electron transfer behaviors of immobilized GOD at the GOD/TiC‐AuNPs‐C60/GCE were investigated by cyclic voltammetry in which a pair of well‐defined, quasi‐reversible redox peaks with the formal potential (E0′) of ‐0.484 V (vs. SCE) in phosphate buffer solution (0.05 M, pH 7.0) at the scan rate of 100 mV·s−1 were obtained. The proposed GOD modified electrode exhibited an excellent electrocatalytic activity to the reduction of glucose, and the currents of glucose reduction peak were linearly related to glucose concentration in a wider linearity range from 5.0 × 10−6 to 1.6 × 10−4 M with a correlation coefficient of 0.9965 and a detection limit of 2.0 × 10−6 M (S/N = 3). The sensitivity and the apparent Michaelis‐Menten constant (KMapp) were determined to be 149.3 μA·mM−1·cm−2 and 6.2 × 10−5 M, respectively. Thus, the protocol will have potential application in studying the electron transfer of enzyme and the design of novel electrochemical biosensors.
Direct Nanopatterning Into Conjugated Polymers Using Interference Crosslinking
Authors: Zhang Xinping , Liu Hongmei , Li Hongwei , Zhai Tianrui
Published: April 2012

Nanoscale photonic structures are patterned directly by exposing a thin film of conjugated polymer to the interference pattern of UV laser beams, thus inducing crosslinking between the polymer molecules in the bright fringes. The crosslinked polymer molecules become indissolvable in organic solvent due to the localized photochemical modification, enabling successful lift‐off of the soft grating structures. The resultant nanodevice exhibits excellent chemical and physical stability. This demonstrates the high spatial resolution of the crosslinking process and introduces a direct nanofabrication technique, which may be utilized in the design of optoelectronic and laser devices.
Temperature dependency of human muscle velocity recovery cycles
Authors: Bostock Hugh , Baumann Corina , Humm Andrea M. , Z'Graggen Werner J.
Published: April 2012

Introduction: Velocity recovery cycles (VRCs) of human muscle action potentials have been proposed as a new technique for studying muscle membrane function. This study was undertaken to determine the temperature dependency of VRC parameters. Methods: VRCs with 1 conditioning stimulus were recorded repeatedly from brachioradialis muscle during cooling, and intramuscular temperature was recorded. VRCs in 6 normal volunteers were measured at 1°C intervals from 34°C to 28°C. The effects of temperature on relative refractory period and early and late supernormality were quantified. Results: Muscle VRC curves shift progressively upward and to the right with cooler temperatures. The most sensitive parameter to temperature changes was relative refractory period, whereas early supernormality was rather insensitive. Late supernormality was unaffected by temperature changes. Conclusions: Knowledge of temperature‐induced changes of muscle VRC parameters is essential for future studies. Thus, the results of this study provide a firm basis for clinical studies with this technique. Muscle Nerve 46: 264–266, 2012
Validation of an adjustment equation for the burst superimposition technique in subjects post‐stroke
Authors: Knarr Brian A. , Higginson Jill S. , Binder‐MacLeod Stuart A.
Published: April 2012

Introduction: Deficits in voluntary force generation may be due to incomplete activation or decreased maximum force‐generating ability (MFGA) of the targeted muscle. The validity of techniques used to measure MFGA in individuals post‐stroke has not been assessed. The objective of this study was to determine the reliability of the MFGA predicted using an adjusted burst superimposition method within a post‐stroke population. Methods: Differences in paretic‐side plantar flexor muscle MFGA between 2 trials was calculated using the standard and adjusted burst superimposition technique for 17 individuals post‐stroke (15 men, 58.7 ± 10 years of age, ≥6 months post‐stroke) to assess reliability of the techniques. Results: The adjusted measurement was shown to be more reliable (P = 0.03), especially when volitional effort differed by >40 N. Conclusions: Reliable measurement of the MFGA in individuals who have sustained a stroke is of clinical importance. These results suggest that the adjusted burst superimposition method may be useful when performing multiple measurements of muscle performance. Muscle Nerve 46: 267–269, 2012
Outcome of prenatally detected bilateral higher urinary tract obstruction or megacystis: sex‐related study on a series of 709 cases
Authors: Al‐Hazmi Hamdan , Dreux Sophie , Delezoide Anne‐Lise , Dommergues Marc , Lortat‐Jacob Stephen , Oury Jean‐François , El‐Ghoneimi Alaa , Muller Françoise
Published: April 2012

Objective

To compare the sex specific outcome of fetuses with prenatally detected urinary tract dilatation, with the exclusion of pyelectasia.

Method

Included in the study were 709 cases of major dilatation of the fetal urinary tract, diagnosed at routine ultrasound scan. For each sex group, cases were divided into two subgroups depending on the level of dilatation. Final diagnosis was based on postnatal evaluation or on fetal autopsy. Postnatal renal function was evaluated using serum creatinine at two years of age.

Results

Bilateral higher urinary tract dilatation was prenatally observed in 148 (20.8%) and lower urinary tract obstruction or bladder dilatation in 561 (79.1%) of the 709 cases (121 female and 588 male fetuses) (P <0.001). Bladder dilatation was less frequent in female fetuses (62%) than in males (82.6%) (P <0.001). At final diagnosis, associated malformations were observed in 53.7% of female fetuses versus 11% in males (P <0.001). The survival rate was 42.7%. Postnatal renal function, evaluated in 289/303 live infants, was impaired in 29.7% of cases and depended on the level of obstruction, but not on the sex.

Conclusion

Prenatally detected urinary tract dilatation has a poor prognosis both in male and female fetuses. Associated malformations are observed more frequently in female than in male fetuses. © 2012 John Wiley & Sons, Ltd.