bluuebunny/crossref_metadata_2025 huggingface dataset:
World's Deepest Through-Tubing Electrical Submersible Pumps
Authors: Julian J.Y.. Y. , Patterson J.C.. C. , Yingst B.E.. E. , Dinkins W.R.. R.
Published: December 2011

This paper describes the development, history, and successful deployment of the world's two deepest through-tubing-conveyed electrical submersible pumps (TTCESPs). These are the first TTCESPs deployed inside of 7-in. casing. Electrical submersible pumps (ESPs) are a form of artificial lift that consists of a pump, motor, and electric cable, typically deployed by a rig and connected to electric power at surface. Their advantage is that they create greater drawdown than other forms of artificial lift, thus achieving higher production rates. However, conventional ESPs require expensive workover rigs to replace pumps, the component that fails most frequently. ConocoPhillips Alaska developed TTCESP technology to replace failed pumps rapidly and economically. In this system, a rig conventionally deploys the electric cable, motor, and seal sections with a special latching device for the pump. The pump is pulled and replaced with slickline (wireline) or coiled tubing, eliminating the requirement of a rig.

The original through-tubing-conveyed (TTC) systems were developed for 7⅝-in.-cased wells. During approximately the past 10 years, it was common belief that they could not be deployed at the Milne Point field in Alaska because of the limitations of its smaller wells (7-in., 26-lbm/ft casing). This paper discusses the enabling technologies that were developed to allow running TTCESPs in 7-in. casing, including a wellhead spoolpiece and low-clearance ESP clamps.

West Sak TTCESP run-time data indicate that the time between rig workovers (RWOs) will increase from 3.5 to 6 years. Pumps can be replaced for 5–10% of rig costs without the safety and environmental impacts associated with rigs. Additionally, production impacts while waiting for a rig are eliminated because slickline and coiled-tubing units are readily available on the North Slope of Alaska. TTC pumps can easily be upsized or downsized to optimize pump flow rate because of changes in production rates. This technology is of interest in areas where rig costs are high, including Arctic, remote, and offshore locations. It is also beneficial where rig availability is low.
A New Proprietary Hybrid-Solvent Process for Improved Mercaptan Removal
Authors: Cadours Renaud , Shah Virenkumar , Weiss Claire
Published: December 2011

Removing mercaptans from sour natural gas has always been considered a challenge. This is becoming an even more important issue with the global trend toward more-stringent specifications for commercial gases.

Amines have been used extensively because of their ability to meet the most severe H2S and CO2 specifications and their very high acid-gas selectivity over hydrocarbons, but they present very limited mercaptans-removal performances. They require an additional treatment step to achieve the total sulfur-content specification in the exported gas. Hybrid solvents are more efficient in removing mercaptans but have the disadvantage of poor acid-gas selectivity over hydrocarbons, resulting in hydrocarbon losses with the separated acid gases.

Total, taking advantage of its extensive knowledge and experience in acid-gas removal with amine mixtures, has developed a new proprietary hybrid-solvent formulation allowing simultaneous absorption of acid gases and of mercaptans, with limited coabsorption of hydrocarbons. (The new hybrid solvent process is Total's proprietary process known as the HySWEET® process, which is a registered trademark.) The solvent was selected at the laboratory scale, with a particular attention given to operation-related constraints (e.g., cost, corrosion, foaming, degradation). The new solvent's acid-gas- and mercaptans-removal performances were then validated on a pilot rig.

The performance of the process has been assessed for several field applications and compared with the performances of conventional amine processes. This allowed evaluating the potential gain achievable by the implementation of the new hybrid solvent. The study identifies the application cases for which the new hybrid solvent will allow an economic and complete mercaptan removal without any additional treatment and identifies the perspective reduction of these additional treatments for the other cases. Besides an economical mercaptan removal, the new hybrid solvent allows a significant reduction in the energy consumption.

The results of the technoeconomic evaluation of the process have been confirmed during the first successful industrial application at the Lacq sour-gas plant in 2008. Half of the gas production is now treated with the hybrid solvent, allowing the plant to achieve high global mercaptans removal.

These results are fully documented in the paper, demonstrating that the newly developed process is a good contender for the development of new sour-gas fields to achieve the increasingly stringent commercial gas specifications.
The Impact of the Movement of Labour: Results from a Model of Bilateral Migration Flows
Authors: Walmsley Terrie L. , Winters Alan , Ahmed Amer
Published: December 2011

The economics literature increasingly recognizes the importance of migration. In this paper, a bilateral global migration model is developed to investigate the impact of lifting restrictions on the movement of labour. Quotas on skilled and unskilled labour in the developed economies are increased by 3% of their labour forces, with the additional labour supplied by developing economies.

This paper improves upon the previous work of Walmsley and Winters (2005). A critical weakness of the previous work was that it was unable to capture the impacts of specific bilateral migration flows or liberalizations between countries. This paper uses a bilateral global migration model that exploits migration data obtained from Parsons, Skeldon, Winters, and Walmsley (2007) that allow the model to account for bilateral migration flows.

The results confirm that restrictions on migration impose significant costs on nearly all countries, with the modest liberalization increasing global GDP by US$ 288 billion. All of the developed (labour importing) economies gain in terms of real incomes. While results differ across the developing (labour exporting) economies, most gain as a result of the higher remittances sent home.
Implementing Teaching Portfolios and Peer Reviews in Tax Courses
Authors: Calegari Michael J. , Geisler Gregory G. , Larkins Ernest R.
Published: December 2011

Extant literature suggests that the process of constructing a teaching portfolio can identify areas to improve, motivate positive changes, and elevate the importance of teaching in academe. This study describes the experience of the tax faculty at a public university in using teaching portfolios and peer reviews to improve the quality of the first two tax courses. The type of teaching portfolio used in this project consists of a course syllabus and a reflective statement that documents the rationale for all components of a course (i.e., lectures, projects, exams, writing assignments, presentations, etc.). The peer review aspect involves written feedback from a colleague on this teaching portfolio. Though research publications are usually subject to extensive peer review, teaching generally is not. Like research, however, teaching can be evaluated and ultimately improved through peer review. Thus, this study can provide valuable guidance to tax professors attempting to improve their courses.
Using Technology to Examine the Entity-Choice Decision
Authors: Nichols Nancy B. , Bryant Stephanie M.
Published: December 2011

The AICPA Model Tax Curriculum (AICPA 1996a) stresses the importance of entity taxation throughout the first two undergraduate tax courses and a master's of accounting program. This paper provides instructors with a case that uses a simplified example of the Boston Celtics, a publicly traded partnership, to highlight the tax and nontax considerations that must be evaluated when making a choice of entity decision. The case also incorporates technological tools including CD-ROM or Internet-based tax research, Excel spreadsheets for preparing tax and cash flow projections, word-processing software, and an optional PowerPoint presentation. The case is designed to be completed in stages throughout the semester.
An Application of the Scholes and Wolfson Model to Examine the Relation between Implicit and Explicit Taxes and Firm Market Structure: An Analysis
Authors: Wright Brian
Published: December 2011

Callihan and White (1999) present a methodology for applying Scholes and Wolfson's (1992) model of implicit tax rates to financial statement data. This methodology is aimed at addressing two issues: (1) measurement of implicit tax rates and (2) determination of the extent to which firms possessing market power can shift implicit tax burdens away from the firm. This paper examines Callihan and White's empirically driven definition of implicit tax rates and points to the pitfalls of using this definition for firms that might possess market power. In particular, I show that, since the Callihan and White measure assumes that firms do, in fact, operate in perfectly competitive markets, it cannot be used validly to measure the magnitude of implicit taxes in the presence of firm market power. Additionally, my analysis casts doubt over the validity of Callihan and White's finding that implicit taxes are lower for firms possessing market power.
Do Firms Use the Deferred Tax Asset Valuation Allowance to Manage Earnings?
Authors: Bauman Christine C. , Bauman Mark P. , Halsey Robert F.
Published: December 2011

This study utilizes a sample comprised of Fortune 500 firms to examine earnings management via changes in the deferred tax asset valuation allowance. The study extends existing research in three ways. First, we document that the earnings effect of a valuation allowance change often cannot be determined from financial statement disclosures. Based on an analysis of sample firms' income tax footnotes, we offer suggestions to improve disclosure policy.

Second, prior research uses the net change in the valuation allowance account as a proxy for the earnings effect of valuation allowance changes. We argue that the amount reported in the effective tax rate reconciliation is a better measure of the income statement effect and document certain significant differences between the measures.

Third, prior research employs cross-sectional regression models in an effort to make generalizations about earnings management behavior. In contrast, we use a contextual approach to assess whether observed valuation allowance changes are consistent with different motivations for earnings manipulation. The contextual analyses are based on identifying firms in the position to engage in various forms of earnings management and examining the earnings effect of valuation allowance changes made by firm managers. Cross-sectional tests find virtually no evidence in support of earnings management. Of particular note, we find that the incidence of “big bath” behavior may be exaggerated. In contrast, a contextual approach identifies specific instances in which earnings management may exist. Thus, the analysis of valuation allowance changes is contextual and requires careful consideration of activity in the allowance account. This point underscores the deficiency in income tax reporting and the need for increased disclosure in this area.
Relationships Between Vertical Jump and Full Squat Power Outputs With Sprint Times in U21 Soccer Players
Authors: López-Segovia Manuel , Marques Mário , van den Tillaar Roland , González-Badillo Juan
Published: December 2011

Relationships Between Vertical Jump and Full Squat Power Outputs With Sprint Times in U21 Soccer Players

The aim of this study was to assess the relationship between power variables in the vertical jump and full squat with the sprint performance in soccer players. Fourteen under-21 soccer players were evaluated in two testing sessions separated by 7 days. In the first testing session, vertical jump height in countermovement was assessed, and power output for both loaded countermovement jump (CMJL) and full squat (FS) exercises in two progressive load tests. The second testing session included sprinting at 10, 20, and 30m (T10, T20, T30, T10-20, T10-30, T20-30). Power variables obtained in the loaded vertical jump with 20kg and full squat exercise with 70kg showed significant relationships with all split times (r=-0.56/-0.79; p≤ 0.01/0.01). The results suggest that power produced either with vertical jump or full squat exercises is an important factor to explain short sprint performance in soccer players. These findings might suggest that certain levels of neuromuscular activation are more related with sprint performance reflecting the greater suitability of loads against others for the improvement of short sprint ability in under-21 soccer players.
Influence of Industrial Environments on the Development of Respiratory Systems and Morphofunctional Features in Preadolescent Boys
Authors: Dziubek Wioletta , Ignasiak Zofia , Rozek Krystyna
Published: December 2011

Influence of Industrial Environments on the Development of Respiratory Systems and Morphofunctional Features in Preadolescent Boys

The present study examines the differences between levels of selected structural and functional features of boys 11-13 years in age from regions with varying levels of air pollution, including an industrial and rural region. The sample consisted of 213 boys from the industrial region and 98 from the rural region. Somatic, respiratory parameters and motor abilities were evaluated in both groups. The analysis of respiratory parameters revealed significantly better development of respiratory systems in boys from the rural region. Additionally, motor abilities were also better developed in boys from the rural region.
Diversity of the Mesostigmata (Acari) in tree-hollows of selected deciduous tree species
Authors: Kaczmarek Sławomir , Marquardt Tomasz , Faleńczyk-Koziróg Katarzyna
Published: December 2011

Diversity of the Mesostigmata (Acari) in tree-hollows of selected deciduous tree species

Rich gamasid communities were found in tree-hollows of horse chestnut (Aesculus hippocastanum), small-leaved lime (Tilia cordata), and white willow (Salix alba) in urban and rural areas in northern Poland (Bydgoszcz and its environs). We recorded there 93 gamasid species of 21 families in a total of 18 tree-hollows. Differences in the dominance structure of gamasid communities at the levels of family and species indicated dissimilarities in the mite communities, depending on tree species and intensity of human impact. The chestnut tree-hollows in both areas were dominated by mites of the family Urodinychidae (with the dominant Uroobovella pyriformis in both cases). The lime tree-hollows were colonized mostly by the Trematuridae (Trichuropoda ovalis) and the Digamasellidae (Dendrolaelaps tenuipilus) in the rural area, whereas by the Ascidae (Iphidozercon gibbus) in the city. The gamasid communities of willow hollows were dominated by the Trematuridae (Trichouropoda ovalis) in the urban area, and by the Digamasellidae (Dendrolaelaps longifallax, D. zwoelferi) in the rural area. Some rare species (e.g. Microgynium rectangulatum or Microsejus truncicola) were also recorded, mostly in the rural area.
Selection of native isolates of Beauveria bassiana (Ascomycota, Hypocreales) for the control of the coffee borer beetle Hypothenemus hampei (Scolytinae) in Brazil
Authors: Dalvi Leandro , Pratissoli Dirceu , Polanczyk Ricardo , Andrade Gilberto
Published: December 2011

Selection of native isolates of Beauveria bassiana (Ascomycota, Hypocreales) for the control of the coffee borer beetle Hypothenemus hampei (Scolytinae) in Brazil

Hypothenemus hampei (coffee borer beetle or coffee berry borer) is the main pest of coffee Coffea spp. in the world. The aim of this study was to select native isolates of the ascomycete Beauveria bassiana for biological control of this pest. We collected 27 isolates on H. hampei from the state of Espírito Santo in Brazil. Isolates CCA-UFES/Bb-15, Bb-11, Bb-4 and Bb-18 were selected, with confirmed beetle mortality of > 60% after spraying with a suspension of 105 conidia/mL. The median lethal concentration (LC50) of these isolates varied from 4.0 × 104 to 7.9 × 104 conidia/mL. The standard isolate (ESALQ-447) showed the highest conidiogenesis, with 8.5 × 106 conidia, followed by CCA-UFES/Bb-18, Bb-11, Bb-15 and Bb-4, all exceeding 4 × 106. Isolates CCA-UFES/Bb-4, Bb-11, Bb-15, and Bb-18 have a potential to control H. hampei.
A New Method of Line Feature Generalization Based on Shape Characteristic Analysis
Authors: Nie Hongshan , Huang Zhijian
Published: December 2011

A New Method of Line Feature Generalization Based on Shape Characteristic Analysis

This paper presents a piecewise line generalization algorithm (PG) based on shape characteristic analysis. An adaptive threshold algorithm is used to detect all corners, from which key points are selected. The line is divided into some segments by the key points and generalized piecewise with the Li-Openshaw algorithm. To analyze the performance, line features with different complexity are used. The experimental results compared with the DP algorithm and the Li-Openshaw algorithm show that the PG has better performance in keeping the shape characteristic with higher position accuracy.
Experimental Study on Permeability and Mechanical Properties of Nanomodified Porous Concrete
Authors: Shirgir Behrooz , Hassani Abolfazl , Khodadadi Ahmad
Published: December 2011

Porosity of porous concrete is an important parameter used for both mechanical properties of pavement and environmental design. Nano-particles have received increasing attention and have been used in various fields such as concrete to develop novel materials with interesting functions, all because of dedicated physical and chemical properties of nanoparticles. The authors describe new findings of an experimental work on mechanical properties and permeability of porous concrete containing nano-silicon dioxide. Plain porous concrete and porous concrete containing micro-silicon dioxide have been studied as control materials. Twenty-eight-day results showed higher compressive and flexural strengths for porous concrete containing nano-silicon dioxide compared with those of plain porous concrete with the same water–cement ratio. It was demonstrated that nano-silicon dioxide was more effective than micro-silicon dioxide in enhancing porous concrete flexural strength. Samples with 5% nano-silicon dioxide by weight of binder presented the highest mechanical properties, in which the flexural and compressive strength of porous concrete were enhanced by 56% and 48%, respectively. From experimental study of the permeability behavior of porous concrete containing nano- and micro-silicon dioxide, it appeared that nano-silicon dioxide and micro-silicon dioxide could both reduce water penetration through porous concrete; however, micro-silicon dioxide was found more effective for equal nanoparticles and material voids.
Bikeability and the 20-min Neighborhood
Authors: McNeil Nathan
Published: December 2011

This study explored a methodology for assessing a neighborhood's bicycle accessibility or “bikeability” on the basis of its mix of infrastructure and destinations, essentially the 20-min neighborhood for bicycles. Prior approaches to assessing bikeability were examined. A new method to measure bikeability that incorporates extensive bicycle infrastructure and land use destination location data is described. The assessment method compared neighborhoods in Portland, Oregon, that had significant differences in bicycle usage. On the basis of the new method, the findings confirmed that, taking into account route infrastructure and destination accessibility, East Portland locations were considerably less bikeable than Inner Portland locations. The assessment method was then rerun to incorporate potential investment and development scenarios to understand how they might affect neighborhood bikeability. The methodology provided steps toward making an objective bikeability assessment—asking if a place could be considered a 20-min neighborhood by bike—and pushed the effort to integrate transportation infrastructure and land-use factors. In its application, the process could be used to explore where planned (or hypothetical) infrastructure or development could be most helpful and which neighborhoods might not receive much added value from the planned improvements.
Estimating Potential Effect of Speed Limits, Built Environment, and Other Factors on Severity of Pedestrian and Cyclist Injuries in Crashes
Authors: Zahabi Seyed Amir H. , Strauss Jillian , Manaugh Kevin , Miranda-Moreno Luis F.
Published: December 2011

Road facilities in urban areas are a major source of injury for nonmotorized road users despite the benefits of nonmotorized transportation. In particular, large Canadian cities such as Montreal face serious problems with pedestrian and cyclist safety. To address these problems, funds are continually allocated through different safety improvement programs such as reduction of speed limits, improvement of intersections, and increased traffic enforcement. However, few analytical tools help to identify and quantify the benefits of countermeasures (e.g., roadway design, speed management strategies, or land use policies) in reducing accident frequency and severity. Injury severity models were developed to determine the effects of road design, built environment, speed limits, and other factors (e.g., vehicle characteristics and movement type) on injury severity levels of pedestrians and cyclists involved in collisions with motor vehicles. Sources of data included police reports describing vehicle–pedestrian and vehicle–cyclist collisions, as well as information on land use, transit network, and road design attributes from the city of Montreal. The impacts of road design, land use, built environment, and other strategies on the injury severity levels of vulnerable road users were investigated. Factors such as darkness, vehicle movement, whether an accident occurred at an intersection, vehicle type, and land use mix affected the severity of pedestrian injuries from collisions. For cyclists, however, only vehicle movement and whether the accident occurred at a signalized intersection had significant effects on the severity of the injury.
Resistance of Wood Wool Cement Board to the Attack of Philippine Termites
Authors: Garcia Carlos M. , Eusebio Dwight A. , San Pablo Marciana R. , Villena Edgar M.
Published: December 2011

The resistance of yemane (Gmelina arborea Roxb.)-based wood wool cement board (WWCB) against Philippine termites was evaluated under laboratory and field conditions. Tests were conducted following the FPRDI standard procedures in determining the resistance of WWCB against subterranean and drywood termites. Results of the laboratory tests showed that WWCB was resistant to both Microcerotermes losbañosensis Oshima and Cryptotermes dudleyi Banks. Under field conditions, WWCB was highly resistant to subterranean termites. There was no remarkable termite damage except for the normal nibbling or initial termite feeding on the board during the 8-year exposure period.
The role of structural and relational governance in creating stable innovation networks: Insights from sustainability-oriented Dutch innovation networks
Authors: Tepic Mersiha , Omta Onno , Trienekens Jacques , Fortuin Frances
Published: December 2011

The aim of the present paper is to explore the role of structural and relational governance in conditions of innovation uncertainty and network heterogeneity in sustainability-oriented innovation networks. The explorative analysis of eighteen innovation networks leads to two important findings. It demonstrates the importance of internalization of stakeholders in the network to create stability in the newly established coalitions and to assure continuation of sustainability-oriented innovation. Also, it demonstrates that even in conditions of innovation, complementarity of structural and relational governance is important. Structural governance (formalization) increases clarity and understanding about partners' differences, reduces uncertainty and increases rational commitment in uncertain and heterogeneous conditions. Relational governance (trust) has a complementary role in this, because it requires time to develop trust in newly established innovation networks with limited previous cooperation. In addition to structural governance (rational commitment), relational governance (trust) is important to prevent attrition in the highly uncertain conditions.
La aristocracia ibérica ante la romanización. Ideología y espacios funerarios en Marroquíes Bajos (Jaén)
Authors: Serrano Peña José Luis , Molinos Molinos Manuel
Published: December 2011

Presentamos el estudio de las necrópolis de un asentamiento periurbano de la ciudad romana de Aurgi (Jaén), en el que, a través del estudio formal e ideológico de los espacios funerarios, planteamos una situación concreta de perduración de las tradiciones ibéricas en el contexto de la romanización en el Alto Guadalquivir.
A Proactive Defense Strategy to Enhance Situational Awareness in Computer Network Security
Authors: Luo Yi , Szidarovszky Ferenc
Published: December 2011

With the development of situational awareness in intrusion defense, a proactive response is a realistic and effective approach against the attackers. It is assumed that each player can update knowledge of the opponent and assess possible future scenarios of the dynamic game based on their previous interactions. Therefore, finding the best current move of the defender is modeled as a discrete-time stochastic control problem. An on-line, convergent, scenario based proactive defense (SPD) algorithm considering adaptive learning is developed based on differential dynamic programming (DDP) to solve the associated optimal control problem. Numerical experiment shows that the new algorithm can help the defender in finding the best dynamic strategies quickly and efficiently. Moreover, the SPD algorithm can provide optimal defensive efforts against possible future attacks within an appropriate time window, so the success of the attack in the possible future interactions can be assessed, improving situational awareness in computer network security.
Unlocking the Locker problem
Authors: Seshaiyer Padmanabhan , Suh Jennifer M. , Freeman Patricia
Published: December 2011

Using technology was not the learning goal in solving this classic benchmark problem, but a way to amplify important mathematics and solidify number characteristic.
Optimal amidoximation conditions of acrylonitrile grafted onto polypropylene by photoirradiation‐induced graft polymerization
Authors: Na Choon‐Ki , Park Hyun‐Ju , Kim Byoung‐Gyu
Published: December 2011

To prepare amidoxime (AO) adsorbents for uranium recovery from seawater, the optimum conditions for graft polymerization and amidoximation of acrylonitrile (AN) group and alkaline treatment of the AO group have been investigated in terms of the uranium adsorption capacity. AN has been grafted onto polypropylene (PP) fabric by photoirradiation‐induced graft polymerization with benzophenone as the photoinitiator. A concentration of AN ≤1.0M, a photoirradiation time of 2 h, and a reaction temperature of 60°C proved to be optimal for the grafting of AN onto PP. The grafted AN groups were effectively converted into AO groups upon reaction with ≥5.0% (w/v) hydroxylamine solution at pH 7.0−9.0 for ≥16 h at 60−80°C. Although widely used for this purpose, we have shown that methanol is not an essential solvent for the amidoximation reaction. Conditioning of the AO group with KOH solution (alkaline treatment) proved to be effective for enhancing the uranium adsorption capacity of amidoximated PP‐g‐AN‐AO fabric, which increased logarithmically with the conditioning time. The AO group density in the PP‐g‐AN‐AO fabric increased linearly with the degree of AN grafting, whereas the uranium adsorption capacity of PP‐g‐AN‐AO fabric conditioned with KOH reached a maximum at a degree of AN grafting of approximately 60%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Direct nanolayer preparation of molecularly imprinted polymers immobilized on multiwalled carbon nanotubes as a surface‐recognition sites and their characterization
Authors: Rezaei B. , Rahmanian O.
Published: December 2011

Molecular imprinting is a method for making artificial receptor sites in a polymer. This article reports the direct nanolayer immobilization of molecularly imprinted polymers (MIPs) on hydroxyl‐functionalized multiwalled carbon nanotubes (MWCNTs) without any binder to improve their characteristics. MIPs were formed for hydrochlorothiazide (HCT) as a template on the surface of the MWCNTs with methacrylic acid (functional monomer) and ethylene glycol dimethacrylate (crosslinking agent) with a thermal polymerization technique. The morphology and stability of the immobilized molecularly imprinted polymers on the surface of multiwalled carbon nanotubes (MIPCNTs) was characterized with scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The resulting MIPCNTs demonstrated favorable selectivity, good stability, and a higher adsorption capacity for the template molecule (93.0 μg/mg) compared to products created by bulk polymerization. The adsorption kinetics of HCT at the surface of the MIPCNTs was in agreement with the second‐order rate equation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A high‐sensitivity LC‐MS/MS method for the determination of 4‐methyl‐piperazine‐1‐carbodithioc acid 3‐cyano‐3, 3‐diphenylpropyl ester hydrochloride in rat plasma and its application to a pharmacokinetics study
Authors: Ji Xiwei , Chen Ye , Li Runtao , Zhou Tianyan , Lu Wei
Published: December 2011

4‐Methyl‐piperazine‐1‐carbodithioc acid 3‐cyano‐3, 3‐diphenylpropyl ester hydrochloride (TM208), a newly synthesized anticancer compound, was quantified using liquid chromatography–tandem mass spectrometry (LC‐MS/MS) for the first time. A simple, rapid and sensitive assay method using propranolol as internal standard (IS) after one‐step precipitation with acetonitrile was developed and validated to determine TM208 in rat plasma. Separation was achieved on a reverse‐phase C18 column with a mobile phase composed of methanol–water (pH4.0) containing 5 m m ammonium acetate in gradient elution mode. A triple quadrupole tandem mass spectrometer with electrospray ionization source was used as detector and operated by multiple reaction monitoring in the positive ion mode. Calibration curves were linear (r > 0.99) between 0.2 and 500 ng/mL. The quantitative limit was 0.2 ng/mL; reliable precision and accuracy were validated by relative standard deviation values in the range 3.44–13.15% and relative error values between −0.58 and −9.78%. The method was successfully applied to preclinical pharmacokinetic studies of TM208. Copyright © 2011 John Wiley & Sons, Ltd.
Fixed bed catalytic reactor modelling—the radial heat transfer problem
Authors: Dixon Anthony G.
Published: December 2011

An interpretation of the state‐of‐the‐art in modelling radial heat transfer in fixed bed catalytic reactors is presented. The persistence of the classical kr–hw model is discussed, problems with typical approaches to obtaining and analysing experimental heat transfer data to get kr and hw are explained, current correlations for kr are evaluated and the contentious history of hw is elaborated. A brief discussion of alternatives to the kr–hw approach and their pros and cons is attempted, and the review is concluded by a look at computational fluid dynamics (CFD) in fixed bed radial heat transfer modelling. © 2011 Canadian Society for Chemical Engineering
Isolation of synaptic terminals from Alzheimer's disease cortex
Authors: Sokolow Sophie , Henkins Kristen M. , Williams Iris A. , Vinters Harry V. , Schmid Ingrid , Cole Gregory M. , Gylys Karen H.
Published: December 2011

Amyloid beta (Aβ) oligomers and phosphorylated tau (p‐tau) aggregates are increasingly identified as potential toxic intermediates in Alzheimer's disease (AD). In cortical AD synapses, p‐tau co‐localizes with Aβ, but the Aβ and p‐tau peptide species responsible for synaptic dysfunction and demise remains unclear. The present experiments were designed to use high‐speed cell sorting techniques to purify synaptosome population based on size, and then extend the method to physically isolate Aβ‐positive synaptosomes with the goal of understanding the nature of Aβ and tau pathology in AD synapses. To examine the purity of size‐gated synaptosomes, samples were first gated on size; particles with sizes between 0.5 and 1.5 microns were collected. Electron microscopy documented a homogenous population of spherical particles with internal vesicles and synaptic densities. Next, size‐gated synaptosomes positive for Aβ were collected by fluorescence activated sorting and then analyzed by immunoblotting techniques. Sorted Aβ‐positive synaptosomes were enriched for amyloid precursor protein (APP) and for Aβ oligomers and aggregates; immunolabeling for p‐tau showed a striking accumulation of p‐tau aggregates compared to the original homogenate and purified synaptosomes. These results confirm co‐localization of Aβ and p‐tau within individual synaptic terminals and provide proof of concept for the utility of flow sorting synaptosomes. © 2011 International Society for Advancement of Cytometry
A Synthetic Overview of Radiolabeled Compounds for β‐Amyloid Targeting
Authors: Ribeiro Morais Goreti , Paulo António , Santos Isabel
Published: December 2011

The formation of β‐amyloid plaques is considered a histopathological hallmark of Alzheimer's disease (AD), a neurodegenerative disorder that affects millions of people worldwide. For effective treatment of AD, diagnosis at an earlier stage of the degenerative process is essential. Therefore, in the last few years significant efforts to find probes for in vitro and/or in vivo imaging of β‐amyloid deposits have been made. This work presents an overview of different small molecules explored as fluorescent or radioactive probes for targeting β‐amyloid deposits. It focuses mainly on the different synthetic approaches used for their synthesis or radiosynthesis but their biological behaviour is also briefly discussed when appropriate.
Silibinin suppresses the maintenance of colorectal cancer stem‐like cells by inhibiting PP2A/AKT/mTOR pathways
Authors: Wang Jir‐You , Chang Chia‐Chi , Chiang Chao‐Ching , Chen Wei‐Ming , Hung Shih‐Chieh
Published: December 2011

Silibinin, an effective chemo‐preventive agent in various cancer types, suppresses cancer cell growth, but its effects on cancer stem‐like cells (CSLCs) remain unclear. This study aimed to examine whether silibinin inhibited the development of CSLCs and disclose the underlying signaling. The colorectal cancer spheroid culture system was used for enriching CSLCs. The effects of silibinin on CSLCs were evaluated by counting sphere numbers, and calculating the percentage of CD133+ cells by flow cytometry and immunofluorescence both in the absence and presence of different concentrations of silibinin. The results showed the sphere number of CCS was 36 ± 9.6 after 15 days of CSLC enrichment in spheroid culture, and the percentage of CD133+ cells increased to 18 ± 6.4% compared to 3 ± 0.8% before enrichment. Treatment with silibinin reduced the sphere formation to 5 ± 3.3 and decreased the CD133+ percentage to 8 ± 2.3%. Interestingly, treatment of silibinin suppressed the activation of the AKT Ser473/mTOR pathway in spheroid culture through suppressing the activity of protein phosphatase 2Ac subunit (PP2Ac). In a xenograft tumor model, treatment with silibinin also inhibited tumor formation rate and tumor growth. Silibinin, which inhibits colon CSLCs self‐renewal and sphere formation by suppressing the PP2Ac/AKT Ser473/mTOR pathway, may be a compound for developing new strategies in modulating CSLCs in cancer therapy. J. Cell. Biochem. 113: 1733–1743, 2012. © 2012 Wiley Periodicals, Inc.
Odontogenic ameloblasts‐associated protein (ODAM), via phosphorylation by bone morphogenetic protein receptor type IB (BMPR–IB), is implicated in ameloblast differentiation
Authors: Lee Hye‐Kyung , Park Jong‐Tae , Cho Young‐Sik , Bae Hyun‐Sook , Cho Moon‐Il , Park Joo‐Cheol
Published: December 2011

To elucidate the function of the odontogenic ameloblast‐associated protein (ODAM) in ameloblasts, we identified more than 74 proteins that interact with ODAM using protoarray. Of the identified proteins, bone morphogenetic protein receptor type‐IB (BMPR‐IB) was physiologically relevant in differentiating ameloblasts. ODAM and BMPR‐IB exhibited similar patterns of expression in vitro, during ameloblast differentiation. ODAM and BMPR‐IB interacted through the C‐terminus of ODAM, which resulted in increased ODAM phosphorylation in the presence of bone morphogenetic protein 2 (BMP‐2). Immunoprecipitation assays using Ser‐Xaa‐Glu (SXE) mutants of ODAM demonstrated that the phosphorylation of ODAM by BMPR‐IB occurs at this motif, and this phosphorylation is required for the activation of MAPKs. ODAM phosphorylation was detected in ameloblasts during ameloblast differentiation and enamel mineralization in vitro and involved in the activation of downstream factors of MAPKs. Therefore, the BMP‐2‐BMPR‐IB‐ODAM‐MAPK signaling cascade has important roles in ameloblast differentiation and enamel mineralization. Our data suggest that ODAM facilitates the progression of tooth development in cooperation with BMPR‐IB through distinct domains of ODAM. J. Cell. Biochem. 113: 1754–1765, 2012. © 2011 Wiley Periodicals, Inc.
Multiple‐exchange‐time xenon polarization transfer contrast (MXTC) MRI: Initial results in animals and healthy volunteers
Authors: Dregely Isabel , Ruset Iulian C. , Mata Jaime F. , Ketel Jeffrey , Ketel Steve , Distelbrink Jan , Altes Talissa A. , Mugler John P. , Wilson Miller G. , William Hersman F. , Ruppert Kai
Published: December 2011

Hyperpolarized xenon‐129 is a noninvasive contrast agent for lung MRI, which upon inhalation dissolves in parenchymal structures, thus mirroring the gas‐exchange process for oxygen in the lung. Multiple‐exchange‐time xenon polarization transfer contrast (MXTC) MRI is an implementation of the XTC MRI technique in four dimensions (three spatial dimensions plus exchange time). The aim of this study was to evaluate the sensitivity of MXTC MRI for the detection of microstructural deformations of the healthy lung in response to gravity‐induced tissue compression and the degree of lung inflation. MXTC MRI was performed in four rabbits and in three healthy human volunteers. Two lung function parameters, one related to tissue‐ to alveolar‐volume ratio and the other to average septal‐wall thickness, were determined regionally. A significant gradient in MXTC MRI parameters, consistent with gravity‐induced lung tissue deformation in the supine imaging position, was found at low lung volumes. At high lung volumes, parameters were generally lower and the gradient in parameter values was less pronounced. Results show that MXTC MRI permits the quantification of subtle changes in healthy lung microstructure. Further, only structures participating in gas exchange are represented in MXTC MRI data, which potentially makes the technique especially sensitive to pathological changes in lung microstructure affecting gas exchange. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Differential effect of isoflurane, medetomidine, and urethane on BOLD responses to acute levo‐tetrahydropalmatine in the rat
Authors: Liu Xiping , Li Rupeng , Yang Zheng , Hudetz Anthony G. , Li Shi‐Jiang
Published: December 2011

Levo‐tetrahydropalmatine (l‐THP) has shown significant promise in preclinical and clinical studies to treat drug addiction. Pharmacological MRI methods can elucidate the regional cerebral effects of l‐THP, but there are potential confounds from the use of general anesthesia. To investigate the possible anesthetic–drug interactions for the pharmacological MRI result of acute l‐THP, we examined acute blood oxygen level‐dependent responses of both 5 and 20 mg/kg l‐THP in naïve rats during general anesthesia achieved with three agents: isoflurane, medetomidine, and urethane. We found that with acute l‐THP administration, isoflurane revealed the smallest blood oxygen level‐dependent activation areas. In addition, urethane had the most activation areas; however, they were all negative. Medetomidine showed mixed positive and negative activations. Region‐specific interactions were found between the l‐THP‐induced blood oxygen level‐dependent responses and the anesthetic agents. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Statistical approaches for conducting network meta‐analysis in drug development
Authors: Jones Byron , Roger James , Lane Peter W. , Lawton Andy , Fletcher Chrissie , Cappelleri Joseph C. , Tate Helen , Moneuse Patrick ,   on behalf of PSI Health Technology Special Interest Group, Evidence Synthesis sub‐team
Published: December 2011

We introduce health technology assessment and evidence synthesis briefly, and then concentrate on the statistical approaches used for conducting network meta‐analysis (NMA) in the development and approval of new health technologies. NMA is an extension of standard meta‐analysis where indirect as well as direct information is combined and can be seen as similar to the analysis of incomplete‐block designs. We illustrate it with an example involving three treatments, using fixed‐effects and random‐effects models, and using frequentist and Bayesian approaches. As most statisticians in the pharmaceutical industry are familiar with SAS® software for analyzing clinical trials, we provide example code for each of the methods we illustrate. One issue that has been overlooked in the literature is the choice of constraints applied to random effects, and we show how this affects the estimates and standard errors and propose a symmetric set of constraints that is equivalent to most current practice. Finally, we discuss the role of statisticians in planning and carrying out NMAs and the strategy for dealing with important issues such as heterogeneity. Copyright © 2011 John Wiley & Sons, Ltd.
An accurate and simple universal curve for the energy‐dependent electron inelastic mean free path
Authors: Seah M. P.
Published: December 2011

The values of inelastic mean free paths (IMFPs) calculated from optical data for the three material categories of elements, inorganic compounds and organic compounds are re‐assessed to provide a simple equation giving an estimate of the IMFP, knowing only the identities of the elements in an analysed layer and the atomic density of that layer. This simple equation is required for quantification of the thicknesses for layers of mixed elements in which the required parameters for use of the popular equation, TPP‐2M, are insufficiently known. It describes the published values, calculated from optical data for energies above 100 eV, to a similar root mean square (RMS) deviation as that for TPP‐2M in the three material categories. The RMS deviation for all three categories averages 8.4%, provided the inorganic data are ‘corrected’ for the published sum rule errors. If, in an analysed layer, only elements are identified and the atomic density is unknown, i.e. only the average Z value of the layer is known, a simpler relation is provided for the IMFP in monolayers with only one unknown parameter Z that exhibits an RMS deviation from the IMFPs calculated from optical data of 11.5%. Copyright © 2011 Crown copyright.
Nitrogen‐Rich Energetic Dianionic Salts of 3, 4‐Bis(1H‐5‐­tetrazolyl)furoxan with Excellent Thermal Stability
Authors: Huang Haifeng , Zhou Zhiming , Liang Lixuan , Song Jinhong , Wang Kai , Cao Dan , Bian Chengming , Sun Wenwen , Xue Min
Published: December 2011

Nitrogen‐rich 3, 4‐bis(1H‐tetrazol‐5‐yl)furoxan (H2BTF, 2) and its energetic salts with excellent thermal stability were successfully synthesized and fully characterized by 1H, and 13C NMR, and IR spectroscopy, differential scanning calorimetry (DSC), and elemental analyses. Additionally, the structures of barium (3) and 1‐methyl‐3, 4, 5‐triamino‐triazolium (10) salts were confirmed by single‐crystal X‐ray diffraction. The densities of the energetic salts paired with organic cations range between 1.56 and 1.85 g·cm–3 as measured by a gas pycnometer. Based on the measured densities and calculated heats of formation, the detonation pressures and velocities are calculated to be in the range 23.4–32.0 GPa and 7939–8915 m·s–1, which make them competitive energetic materials.
Diel changes in resource use and diet overlap in temperate stream fishes
Authors: Nakagawa Hikaru , Yamane Hideyuki , Yasugi Masaki , Fujita Tomohiko , Yokoi Kenichi , Ashiwa Hiroshi , Kitada Naoki , Takano Hiroki , Suzuki Noriyasu , Kishimoto Junpei , Maeda Hajime , Yamano Hitomi , Ito Takehiko , Maruyama Hiroaki , Tominaga Koji , Hatakeyama Emi , Goto Motoyasu , Takahashi Daisuke
Published: December 2011

Interspecific variation in diel‐scale temporal niches is common in natural communities. Such variation changes population dynamics via effects on the growth and reproduction of individuals. Also at the community level, theory predicts that animals can reduce competition for shared resources by changing diel activity in certain situations. However, the role of diel activity at the community‐level has not been examined sufficiently. In this study, to examine whether the diel‐scale temporal niche act as a competition‐mitigating mechanism for stream fishes at the community level, we surveyed diel changes in microhabitat use and foraging, and the pattern of interspecific diet overlap in the middle reaches of a temperate stream where various fish species that seemed to be either nocturnal or diurnal coexisted. Our results suggest that the fishes forage during both daytime and night, but change their foraging mode at different times of the day, so that the foraging habits of these fish species cannot be divided simply into nocturnal and diurnal. Furthermore, fishes appeared to aggregate in the vicinity of common food resources during time zones with high availability of the resources, and therefore, inter‐guild diet overlap was high during certain time zones. On the other hand, when inter‐guild diet overlap was low, each fish species used foods or microhabitats that did not any have the potential to be used by species of another guild. Therefore, we conclude that variation in diel niche use is influenced by variation in the fundamental niche and food supply or availability rather than by competitive interaction between fishes in the stream fish community.
Chinese hamster AP endonuclease operates by a two‐metal ion assisted catalytic mechanism
Authors: Borjigin Mandula , Arenaz Pablo , Stec Boguslaw
Published: December 2011

The APE1, an important mammalian AP endonuclease, is an essential enzyme in the base excision DNA repair pathway (BER). The number of metal ions involved directly in the catalysis remains controversial. Here we describe the metal ion titration experiments that demonstrate the requirement for two metal ions for the endonuclease activity of the Chinese hamster APE1. The titration with the non‐activating metal ion La3+ showed a biphasic behavior with activating and inhibitory effects of La3+ in the range of 0–100 μM in the presence of 5 mM Mg2+. Modeling of the enzyme‐substrate/product complexes provided insight into the endonuclease activity and elucidated the nature of the crystal structures. Accordingly, we proposed a reaction scheme for the two‐metal ion assisted catalysis of chAPE1 endonuclease activity.