bluuebunny/crossref_metadata_2025 huggingface dataset:
Luminescent Method for Pressure Measurement
Authors: Khalil Gamal E. , Crafton Jim W. , Fonov Sergey D. , Sellers Marvin , Dabiri Dana
Published: January 2013

Pressure‐sensitive paint (PSP) is an image‐based technology that provides a convenient method for continuous and nonintrusive global mapping of pressure distributions on aerodynamic surfaces. Its development offers a feasible alternative to pressure measurements obtained from point‐to‐point instruments such as pressure taps or pressure transducers, which were often costly to utilize and intrusive to the flow being studied. The paints are composed of pressure‐sensitive dye, which is made of an oxygen‐sensitive luminescent dye, that is incorporated into an oxygen‐permeable polymer binder and dissolved in a volatile solvent to form a paint that can be easily applied to surfaces using a spray can or airbrush. The emitted intensity of the pressure‐sensitive paint is quenched by collisions with oxygen molecules; the intensity of the emitted light is inversely proportional to the pressure at the surface. The measurement is accomplished by applying the paint to the surface of interest and illuminating the surface with blue or UV light to excite the dye. The surface is imaged through a filter that isolates the excitation light from the pressure‐sensitive luminescence of the paint. Each pixel on the camera then acts as a nonintrusive pressure tap, and therefore, continuous distributions of the pressure on the painted surface are acquired. Standard pressure paints can be used for mean measurements with response times of about 1 Hz, and fast response systems can be used for high frequency measurements, with a bandwidth of over 100 kHz.

The use of PSP is becoming more common in large transonic tunnels, with production systems in use in several facilities such as AEDC, ARA, DLR, ADD, JAXA, and AVIC. These measurements have been conducted using both binary and lifetime‐based systems. While PSP has proven effective in transonic tunnels, PSP measurements in large low‐speed tunnels have proven particularly challenging. A significant reason for this difficulty is that in low‐speed tunnels the dynamic pressures are small (∼1 kPa at 40 m/s), and therefore, the dynamic range of the signal to be detected in a low‐speed tunnel is often 1% or less. Recent advances in cameras, illumination sources, and paint technology have extended the operating range of PSP systems to as low as 40 m/s. This chapter will cover in detail the following: principles and theoretical treatment of pressure‐sensitive paints, pressure‐sensitive dyes, polymers, measurement methods, and practical implementations of PSP to a wide series of wind tunnel applications.
Flow Measurement
Authors: Fontaine Arnold A. , Manning Keefe B. , Deutsch Steven
Published: January 2013

Interest in understanding fluid flows, and attempts to measure flow‐related phenomenon has had a long history in the scientific and medical communities. The name “flow measurement” is a broad term that can encompass the measurement of many different flow‐related parameters. It has been noticed that flow measurement techniques have advanced significantly in capability, versatility, and in many ways, complexity. The study characterizes measurement techniques as invasive or noninvasive, and direct or indirect. This Chapter primarily focuses on the measurement of those parameters that are most often desired in a biomedical/bioengineering application, volume flow rate, and velocity. It has been found that in both the clinical environment and the laboratory environment, the measurements of the volume flow rate of a fluid as a function of time can be an important parameter and can be measured by electromagnetic flow meters and ultrasound techniques. Various techniques such as thermal anemometry, Doppler ultrasound and MR flow mapping particle image velocimetry and particle tracking velocimetry have been discussed comprehensively to measure fluid velocity or wall shear.
Industrial Energy Efficiency
Authors: Gopalakrishnan B. , Gupta D. P. , Mardikar, Y. , Chaudhari S.
Published: January 2013

The present Chapter focuses on industrial energy efficiency and how it is helpful in protecting our environment in terms of reduction in emissions. Environmentally conscious manufacturing has made significant gains on account of improvements in energy efficiency. The study finds that industrial energy efficiency is necessary for several reasons. The energy efficiency reduce operating costs and hence lead to manufacturing industry becoming globally competitive and contribute to increase profitability and growth. Nonetheless, energy efficiency reduces the consumption of fossil fuels, hence playing a role in controlling the cost of energy to have a positive impact on every facet of the society. It has been found that the programs of the U.S. DOE' EERE and Industrial Technologies Program have gone a long way in helping industry and hence the nation to become energy efficient through a myriad of programs.
Plastics Testing
Authors: Shah Vishu
Published: January 2013

The present chapter reviews plastic material. Plastics, unlike metals, ceramics, and other traditional materials, do not exhibit a linear stress‐strain relationship and are sensitive to change in temperature, rate of loading environment, and so on. Over the years ASTM has done an excellent job in developing and providing the plastic industry with standard testing procedures. These standards have and continue to play a preeminent role in all aspects important to the effective utilization of plastics. The study finds that mechanical properties, among all the properties of plastic materials, are often the most important properties because virtually all service conditions and the majority of end‐use applications involve some degree of mechanical loading. Several tests have been presented to study the fatigue behavior, hardness, and thermal, optical, and electrical properties of plastic materials. The study also notes that environmental factors have significant detrimental effects on appearance and properties. Therefore, any attempt to design plastic parts without a clear understanding of the degradation mechanisms induced by the environment would result in a premature failure of the product.
Data Acquisition and Display Systems
Authors: Milliman Philip C.
Published: January 2013

Data acquisition includes acquiring raw data from the process being measured and converting data into usable units. A digital‐to‐analog (D/A) and analog‐to‐digital (A/D) converter performs the actual processing required to bring analog information from or to the process. This chapter attempts to cover aspects of data acquisition and manipulation that may help the engineer better understand issues and give a foundation for using and even constructing tools. A discussion of pros and cons of different strategies helps the reader to understand the trade‐offs in system selection and construction. Often the data obtained from a process are not in the form or units desired and several methods of transforming data to produce proper units, reduce storage quantity, and reduce noise have been described. The current values can be inspected and stored for inspection later, values can be trended, alarm conditions can be detected and reported, or some output back to the process can be performed. Finally, all relevant aspects regarding data analysis and data communications have been displayed comprehensively. Other data acquisition and display topics have also been covered such as data chain, web programs and interfaces, configuration versus implementation and store and forward.
Enzymatic Fragment Condensation of Side Chain‐Protected Peptides using Subtilisin A in Anhydrous Organic Solvents: A General Strategy for Industrial Peptide Synthesis
Authors: Nuijens Timo , Schepers Annette H. M. , Cusan Claudia , Kruijtzer John A. W. , Rijkers Dirk T. S. , Liskamp Rob M. J. , Quaedflieg Peter J. L. M.
Published: January 2013

Herein, the enzymatic condensation of side chain‐protected peptide fragments using subtilisin A in anhydrous organic solvents is described. A screening with dipeptide Cbz‐Val‐Xxx carboxamidomethyl esters with H‐Xxx‐Val‐NH2 nucleophiles was performed, wherein Xxx stands for every (side chain‐protected) amino acid residue. Finally, it was demonstrated that it is feasible to enzymatically condense larger peptide fragments (up to the 10‐mer level) bearing multiple side chain‐protecting groups with very high conversion.
Preactivation: An Alternative Strategy in Stereoselective Glycosylation and Oligosaccharide Synthesis
Authors: Yang Lin , Qin Qi , Ye Xin‐Shan
Published: January 2013

The multifaceted biological importance of carbohydrates has made them very popular targets in modern synthetic chemistry. Great progress has been made in stereoselective glycosylation methods and the construction of complex oligosaccharides. This Focus Review highlights the versatile applications of preactivation strategies in stereoselective glycosylation and oligosaccharide synthesis. Recent advances in synthetic methods, such as 4,6‐O‐benzylidene‐acetal‐directed β‐mannosylation, the 1,2‐cis‐glycosylation mediated by a chiral auxiliary, the use of an oxazolidinone or carbonate protecting group, and glycosylation with participating additives, are described. Various examples of sequential glycosylation based on preactivation protocols for efficient oligosaccharide assembly are also summarized.
A comparison of techniques for measuring sensemaking and learning within participant‐generated summaries
Authors: Wilson Mathew J. , Wilson Max L.
Published: January 2013

While it is easy to identify whether someone has found a piece of information during a search task, it is much harder to measure how much someone has learned during the search process. Searchers who are learning often exhibit exploratory behaviors, and so current research is often focused on improving support for exploratory search. Consequently, we need effective measures of learning to demonstrate better support for exploratory search. Some approaches, such as quizzes, measure recall when learning from a fixed source of information. This research, however, focuses on techniques for measuring open‐ended learning, which often involve analyzing handwritten summaries produced by participants after a task. There are two common techniques for analyzing such summaries: (a) counting facts and statements and (b) judging topic coverage. Both of these techniques, however, can be easily confounded by simple variables such as summary length. This article presents a new technique that measures depth of learning within written summaries based on Bloom's taxonomy (B.S. Bloom & M.D. Engelhart, 1956). This technique was generated using grounded theory and is designed to be less susceptible to such confounding variables. Together, these three categories of measure were compared by applying them to a large collection of written summaries produced in a task‐based study, and our results provide insights into each of their strengths and weaknesses. Both fact‐to‐statement ratio and our own measure of depth of learning were effective while being less affected by confounding variables. Recommendations and clear areas of future work are provided to help continued research into supporting sensemaking and learning.
Iron‐Functionalized Silica Nanoparticles as a Highly Efficient Adsorbent and Catalyst for Toluene Oxidation in the Gas Phase
Authors: Popova Margarita , Ristić Alenka , Lazar Karoly , Maučec Darja , Vassileva Mihaela , Novak Tušar Nataša
Published: January 2013

Catalytic oxidation is one of the most important industrially applicable processes for the decomposition of volatile organic compounds (VOCs) in polluted air. The advanced VOC removal process is composed of an adsorption unit and a catalytic incinerator. Many efforts have been made to design a combined adsorption–catalytic unit with optimal activity and selectivity. We demonstrate that iron‐functionalized silica nanoparticles with interparticle mesoporosity (FeKIL‐2) act as highly efficient adsorbents and catalysts with optimal Fe/Si molar ratios of 0.01 in toluene oxidation as model VOCs in the gas phase. By using UV/Vis, FTIR, and Mössbauer spectroscopic techniques, we prove that the enhanced activity of the catalyst is attributed to iron incorporated into the silica matrix, which depends on the iron content. The iron content with Fe/Si≤0.01 leads to the formation of stable Fe3+ ions in the silica matrix, which ensures easier oxygen release from the catalyst (Fe3+/Fe2+ redox cycles). The increase in the iron content with Fe/Si>0.01 leads to the formation of oligonuclear iron complexes. The material thus introduces a promising, environmentally friendly, cost‐effective, and highly efficient catalyst with combined adsorption and catalytic properties for the removal of low‐concentration VOC from polluted air.
TetrathiafulvaleneBenzothiadiazoles as Redox‐Tunable Donor–Acceptor Systems: Synthesis and Photophysical Study
Authors: Pop Flavia , Amacher Anneliese , Avarvari Narcis , Ding Jie , Daku Latevi Max Lawson , Hauser Andreas , Koch Marius , Hauser Jürg , Liu Shi‐Xia , Decurtins Silvio
Published: January 2013

Electrochemical and photophysical analysis of new donor–acceptor systems 2 and 3, in which a benzothiadiazole (BTD) unit is covalently linked to a tetrathiafulvalene (TTF) core, have verified that the lowest excited state can be ascribed to an intramolecular‐charge‐transfer (ICT) π(TTF)→π*(benzothiadiazole) transition. Owing to better overlap of the HOMO and LUMO in the fused scaffold of compound 3, the intensity of the 1ICT band is substantially higher compared to that in compound 2. The corresponding CT fluorescence is also observed in both cases. The radical cation TTF+. is easily observed through chemical and electrochemical oxidation by performing steady‐state absorption experiments. Interestingly, compound 2 is photo‐oxidized under aerobic conditions.
Synchronizing Steric and Electronic Effects in {RuII(NNNN,P)} Complexes: The Catalytic Dehydrative Alkylation of Anilines by Using Alcohols as a Case Study
Authors: Weickmann Daniel , Frey Wolfgang , Plietker Bernd
Published: January 2013

A series of new hexacoordinated {RuII(NNNN,P)} complexes was prepared from [RuCl2(R3P)3]. Their structure was determined by X‐ray crystallography. The catalytic potential of this new class of complexes was tested in the alkylation of aniline with benzyl alcohol. In this test reaction, the influence of the counteranion plus electronic influences at the tetradentate ligand and the phosphine ligand were examined. The electrochemistry of all complexes was studied by cyclic voltammetry. Depending on the substituent at the ligand backbone, the complexes showed a different behavior. For all N‐benzyl substituted complexes, reversible RuII/III redox potentials were observed, whereas the N‐methyl substituted complex possessed an irreversible oxidation event at small scan rates. Furthermore, the electronic influence of different substituents at the ligand scaffold and at the phosphine on the RuII/III redox potential was investigated. The measured E0 values were correlated to the theoretically determined HOMO energies of the complexes. In addition, these HOMO energies correlated well with the reactivity of the single complexes in the alkylation of aniline with benzyl alcohol. The exact balance of redox potential and reactivity appears to be crucial for synchronizing the multiple hydrogen‐transfer events. The optimized catalyst structure was applied in a screening on scope and limitation in the catalytic dehydrative alkylation of anilines by using alcohols.
Inner Workings of a Cinchona Alkaloid Catalyzed Oxa‐Michael Cyclization: Evidence for a Concerted Hydrogen‐Bond‐Network Mechanism
Authors: Hintermann Lukas , Ackerstaff Jens , Boeck Florian
Published: January 2013

Cinchona alkaloids catalyze the oxa‐Michael cyclization of 4‐(2‐hydroxyphenyl)‐2‐butenoates to benzo‐2,3‐dihydrofuran‐2‐yl acetates and related substrates in up to 99 % yield and 91 % ee(ee=enantiomeric excess). Catalyst and substrate variation studies reveal an important role of the alkaloid hydroxy group in the reaction mechanism, but not in the sense of a hydrogen‐bonding activation of the carbonyl group of the substrate as assumed by the Hiemstra–Wynberg mechanism of bifunctional catalysis. Deuterium labeling at C‐2 of the substrate shows that addition of ROH to the alkenoate occurs withsyndiastereoselectivity of ≥99:1, suggesting a mechanism‐based specificity. A concerted hydrogen‐bond network mechanism is proposed, in which the alkaloid hydroxy group acts as a general acid in the protonation of the α‐carbanionic center of the product enolate. The importance of concerted hydrogen‐bond network mechanisms in organocatalytic reactions is discussed. The relative stereochemistry of protonation is proposed as analytical tool for detecting concerted addition mechanisms, as opposed to ionic 1,4‐additions.
Microenvironment Effects in Electrocatalysis: Ionic‐Liquid‐Like Coating on Carbon Nanotubes Enhances the Pd‐Electrocatalytic Alcohol Oxidation
Authors: Li Shuwen , Dong Zhengping , Yang Honglei , Guo Shujing , Gou Galian , Ren Ren , Zhu Zhejun , Jin Jun , Ma Jiantai
Published: January 2013

A new catalyst consisting of ionic liquid (IL)‐functionalized carbon nanotubes (CNTs) obtained through 1,3‐dipolar cycloaddition support‐enhanced electrocatalytic Pd nanoparticles (Pd@IL(Cl−)‐CNTs) was successfully fabricated and applied in direct ethanol alkaline fuel cells. The morphology, structure, component and stability of Pd@IL(Cl−)‐CNTs were systematic characterized by transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM), Raman spectra, thermogravimetric analysis (TGA) and X‐ray diffraction (XRD). The new catalyst exhibited higher electrocatalytic activity, better tolerance and electrochemical stability than the Pd nanoparticles (NPs) immobilized on CNTs (Pd@CNTs), which was ascribed to the effects of the IL, larger electrochemically active surface area (ECSA), and greater processing performance. Cyclic voltammograms (CVs) at various scan rates illustrated that the oxidation behaviors of ethanol at all electrodes were controlled by diffusion processes. The investigation of the different counteranions demonstrated that the performance of the IL‐CNTs hybrid material was profoundly influenced by the subtly varied structures of the IL moiety. All the results indicated that the Pd@IL(Cl−)‐CNTs catalyst is an efficient anode catalyst, which has potential applications in direct ethanol fuel cells and the strategy of IL functionalization of CNTs could be available to prepare other carbonaceous carrier supports to enhance the dispersivity, stability, and catalytic performance of metal NPs as well.
Molecular and phylogenetic characterization of honey bee viruses, Nosema microsporidia, protozoan parasites, and parasitic mites in China
Authors: Yang Bu , Peng Guangda , Li Tianbang , Kadowaki Tatsuhiko
Published: January 2013

China has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana‐infecting SBV, and relatively homogenous populations of IAPV and A. meliifera‐infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast‐encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees.
Linking spatial earthworm distribution to macropore numbers and hydrological effectiveness
Authors: van Schaik Loes , Palm Juliane , Klaus Julian , Zehe Erwin , Schröder Boris
Published: January 2013

Due to its high spatial and temporal variability, preferential flow is difficult to measure and quantify. Earthworms create macropores that provide common pathways for preferential flow. Therefore in this article, we link earthworm abundance to macropore numbers and hydrological effectiveness, with the future aim to use species distribution models of earthworms for the spatial parameterization of preferential flow.

Earthworms are generally categorized into three ecological types with varying burrowing behaviour, resulting in a different impact on soil hydrological processes. Therefore, we studied the relationships between the abundance of the earthworm ecological types and macropores of different size classes and in different soil depths. The abundance and biomass of earthworms were well correlated to different sizes of macropores in different soil depths. This is mainly the case for the larger, vertically oriented macropores (>6 mm diameter), which are generally connected to the soil surface and hydrologically most effective. The correlation of total earthworm biomass and macropores ranges from 0·72 to 0·89 for different soil depths.

Although there is quite some variation in infiltration patterns, infiltration from macropores into the matrix is profile‐specific, as it varies strongly between profiles, but not within one profile. Macropore coating seems to have a larger effect on this macropore matrix interaction than the soil physical properties of the matrix. Although the amount of macropores and their effectiveness are clearly related to the earthworm distribution, the variation in infiltration from macropores to soil matrix should be further studied. Copyright © 2013 John Wiley & Sons, Ltd.
Response surface optimization of ultrasonic‐assisted extraction of carotenoids from oil palm (Elaeis guineensisJacq.) fronds
Authors: Ofori‐Boateng C. , Lee K. T.
Published: January 2013

Oil palm (Elaeis guineensisJacq.) fronds (OPF) are the most abundant oil palm solid wastes that are generated during oil palm agriculture and harvest. Palm oil and some other palm wastes have been reported to contain high concentrations of carotenoids with vital bioactive properties. However, the extraction and quantification of carotenoids fromOPFhave not been reported. In this study, ultrasonic‐assisted extraction,HPLC–FLDfor quantification, and response surface methodology (RSM) for optimization of β‐carotene, lutein, and zeaxanthin fromOPFextracts were investigated. The effects of extraction temperature (X1: 30–70°C), extraction time (X2: 10–50 min), and solvent–sample ratio (X3: 10–50 mL/g) on the recovery of β‐carotene (Y1), lutein (Y2), and zeaxanthin (Y3) were investigated using three‐levelBox–Behnken design (BBD) experiment. At a desirability of 1, the optimum extraction conditions for β‐carotene (30.14°C, 37.11 min, and 23.18 mL/g), lutein (30.00°C, 39.09 min, and 19.24 mL/g), and zeaxanthin (30.09°C, 36.76 min, and 22.38 mL/g) yielded carotenoid concentrations of 17.95 μg/g dry weight (DW), 261.99 μg/gDW, and 29.99 μg/gDW, respectively.
Hepatitis B virus hepatotropism is mediated by specific receptor recognition in the liver and not restricted to susceptible hosts
Authors: Schieck Alexa , Schulze Andreas , Gähler Caroline , Müller Thomas , Haberkorn Uwe , Alexandrov Alexander , Urban Stephan , Mier Walter
Published: January 2013

The human hepatitis B virus (HBV) causes acute and chronic infections in humans and chimpanzees. HBV infects its hosts at minimal inoculation doses and replicates exclusively in hepatocytes. The viral determinants for the pronounced species specificity and the high efficacy to address hepatocytes in vivo are unknown. Previous findings showed that N-terminally myristoylated peptides constituting a receptor binding domain of the HBV large envelope (L)-protein block HBV entry in vitro and in vivo. Here we investigate the ability of such peptidic receptor ligands to target the liver. Injection of radioactively labeled HBVpreS-lipopeptides resulted in rapid accumulation in livers of mice, rats, and dogs but not cynomolgus monkeys. Without lipid moiety the peptide was excreted by renal filtration, indicating its possible retention through the lipid by serum factors. Organ distribution studies of 26 HBVpreS peptide variants revealed a correlation of HBV infection inhibition activity and the ability to target mouse livers. Together with complementary studies using primary hepatocytes of different species, we hypothesize that HBV hepatotropism is mediated through specific binding of the myristoylated N-terminal preS1-domain of the HBV L-protein to a hepatocyte specific receptor. Moreover, the restricted infectivity of HBV to human primates is not generally determined by the absence of this binding receptor in nonsusceptible hosts (e.g., mice) but related to postbinding step(s) (e.g., membrane fusion).
Conclusion
: HBVpreS-lipopeptides target to the liver. This observation has important clinical implications regarding the pharmacokinetic properties of Myrcludex B, the first entry inhibitor for HBV/HDV. In addition, this provides the basis for the application of the peptides as vehicles for hepatocyte-specific drug targeting. (HEPATOLOGY 2013)
Coupled heat and mass transfer by MHD free convection flow along a vertical plate with streamwise temperature and species concentration variations
Authors: Chamkha Ali J. , EL‐Kabeir S.M.M. , Rashad A.M.
Published: December 2012

The problem of steady, laminar, coupled heat and mass transfer by MHD free convective boundary‐layer flow along a vertical flat plate with the combined effects of streamwise sinusoidal variations of both the surface temperature and the species concentration in the presence of Soret and Dufour effects is considered. A suitable set of dimensionless variables is used to transform the governing equations of the problem into a non‐similar form. The resulting non‐similar equations have the property that they reduce to various special cases previously considered in the literature. An adequate and efficient implicit, tri‐diagonal finite difference scheme is employed for the numerical solution of the obtained equations. Various comparisons with previously published work are performed and the results are found to be in excellent agreement. A representative set of numerical results for the velocity, temperature, and concentration profiles as well as the surface shear stress, rate of heat transfer, and the rate of mass transfer is presented graphically for various parametric conditions and is discussed. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21033
Stem Cell Models for Drug Discovery and Toxicology Studies
Authors: Liu Wenwei , Deng Yaguang , Liu Ying , Gong Wenrong , Deng Wenbin
Published: January 2013

Human stem cells and their derivatives could provide virtually unlimited sources of tissue for a wide range of toxicity models that could complement conventional animal models with more relevant, humanized versions. Human embryonic stem cells (hESCs) have already been proven valuable for drug/toxicity screens and mechanistic studies including analysis of disease pathway and developmental toxicity. Human‐induced pluripotent stem cells (iPSCs), which are generated by reprogramming somatic cells back to become hESC‐like cells, allow assays to be designed where the contribution of an individual's genetic background or environmental exposure history to toxicity response can be determined. Comprehensive profiling of hESC/iPSCs via genomics, proteomics, transcriptomics, and metabolomics could be used to elucidate pathway perturbations that underlie toxicity and disease, enabling the development of predictive assays for toxicity. While technological hurdles still exist for widespread use and implementation, incorporation of human stem cell based assays into drug discovery and toxicity testing offers the potential for safer, more customized medicines and more accurate risk assessment for environmental toxicants, as well as reduced costs and decreased use of animal models. We examine limitations and deficiencies of current toxicology approaches and how human stem cell based in vitro assays may overcome them. We describe how human stem cells are used for predictive toxicology. We also identify technological limitations that prevent stem cells from being integrated into standard practice, as well as new tools and technologies that may overcome them. We discuss research priorities that are most useful for transforming cell‐based toxicology models into reality, and research areas in which stem cell technology could make substantial contributions to the development and implementation of stem cell based models for toxicity testing. Increased use of human in vitro models of toxicity could reduce the use of animals in safety and risk assessment studies and offers the potential to dramatically enhance our understanding of the molecular basis of toxicity, leading to improved human models and assays for predicting biological response to drugs and environmental hazards. © 2012 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:17‐27, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21470
Importance of Detecting Multidrug Resistance Proteins in Acute Leukemia Prognosis and Therapy
Authors: de Moraes Ana Carolina Rabello , Maranho Caroline Klein , Rauber Gabriela Schneider , Santos‐Silva Maria Cláudia
Published: January 2013

Multidrug resistance (MDR) is a multifactorial phenomenon and the role of these proteins in generating the MDR phenotype is controversial. With this in mind, this review compiled the current data on the role of ABCB1, ABCC1, and LRP proteins in the prognosis of hematologic neoplasms and their influence on the choice of therapy. Literature showed that the detection of these proteins, mainly ABCB1, is important in the AL prognosis. However, there is controversy regarding the methodology used for their detection. In summary, the expression and activity profiles of ABCB1, ABCC1, and LRP, proteins capable of promoting the efflux of a variety of chemotherapeutic agents from the cell cytoplasm represent one of the greatest causes of failure in AL treatment. J. Clin. Lab. Anal. 27:62–71, 2013. © 2012 Wiley Periodicals, Inc.
Quantifying image distortion of orthopedic materials in magnetic resonance imaging
Authors: Koff Matthew F. , Shah Parina , Koch Kevin M. , Potter Hollis G.
Published: January 2013

Purpose:

To determine the magnitude of image distortion between two‐dimensional (2D) fast‐spin‐echo (FSE) images and 3D‐MAVRIC by using a phantom with samples of common materials used in total joint arthroplasty.

Materials and Methods:

A phantom was constructed to hold samples of 316 stainless steel, cobalt chrome, titanium, and ultra‐high molecular weight polyethylene (UHMWPE), and to permit tracking of points between 2D‐FSE and 3D‐MAVRIC sequences. Imaging was performed with a 1.5 Tesla scanner. The displacement of points between the two acquisitions in regions of varying distance from the material sample was calculated. Measured displacements were compared with theoretical displacements calculated from MAVRIC frequency field maps, and to the known phantom dimensions.

Results:

Bulk in‐plane artifacts increased from the control scan (0.20 ± 0.07 mm), to UHMWPE (0.23 ± 0.04 mm), titanium (0.40 ± 0.34 mm), cobalt chrome (1.35 ± 0.57 mm), and to stainless steel (2.56 ± 0.62 mm). A similar pattern was found for bulk through‐plane measurements: control scan (0.36 ± 0.08 mm), UHMWPE (0.38 ± 0.05 mm), titanium (1.11 ± 0.51 mm), and cobalt chrome (2.08 ± 1.83 mm). Large distortions were observed near the metal samples, and reduced with distance from the samples. The differences between the measured displacement and theoretical displacement was typically less than one pixel or one slice dimension for in‐plane and through‐plane measurements, respectively. The difference between the 3D‐MAVRIC and known dimensions of the phantom was less than two pixels, whereas the results for the 2D‐FSE were less consistent.

Conclusion:

Distortion was reduced in 3D‐MAVRIC scans. Measured distortions corresponded well to theoretical calculations from frequency field map data. J. Magn. Reson. Imaging 2013;38:610–618. © 2013 Wiley Periodicals, Inc.
Comparison of dixon and T1‐weighted MR methods to assess the degree of fat infiltration in duchenne muscular dystrophy patients
Authors: Wokke Beatrijs H. , Bos Clemens , Reijnierse Monique , van Rijswijk Carla S. , Eggers Holger , Webb Andrew , Verschuuren Jan J. , Kan Hermien E.
Published: January 2013

Purpose:

To compare different lipid multipeak spectral models to the single‐peak model in Dixon‐based fat‐water separation and to evaluate differences between visually scored magnetic resonance (MR) images and quantitatively assessed fat fractions in muscle of Duchenne muscular dystrophy patients.

Materials and Methods:

T1‐weighted and 3‐point Dixon imaging of the upper and lower leg was performed in 13 Duchenne patients and six healthy controls. Three‐, four‐, and five‐peak lipid spectrum models were compared to a single‐peak model and to each other. T1‐weighted images were visually scored by two radiologists and quantitative fat fractions were obtained from Dixon images.

Results:

Differences between the multipeak spectral models were minimal. The three‐peak model was used for subsequent comparisons. Although there was high correlation between quantitative and visual scores, visual scores were consistently higher than quantitative values of the same muscles.

Conclusion:

There are minor differences between the various lipid spectral models in terms of quantifying fat fraction in a large number of skeletal muscles in the legs of Duchenne patients and healthy controls. Quantitative 3‐point Dixon MRI is more precise and reliable than visual radiological methods for evaluation of fat fractions for potential longitudinal follow‐up or therapy evaluation of Duchenne patients. J. Magn. Reson. Imaging 2013;38:619–624. © 2013 Wiley Periodicals, Inc.
Estimating abundance and population trends when detection is low and highly variable: A comparison of three methods for the Hermann's tortoise
Authors: Couturier Thibaut , Cheylan Marc , Bertolero Albert , Astruc Guillelme , Besnard Aurelien
Published: January 2013

Assessing population trends is a basic prerequisite to carrying out adequate conservation strategies. Selecting an appropriate method to monitor animal populations can be challenging, particularly for low‐detection species such as reptiles. This study compares 3 detection‐corrected abundance methods (capture–recapture, distance sampling, and N‐mixture) used to assess population size of the threatened Hermann's tortoise. We used a single dataset of 432 adult tortoise observations collected at 118 sampling sites in the Plaine des Maures, southeastern France. We also used a dataset of 520 tortoise observations based on radiotelemetry data collected from 10 adult females to estimate and model the availability (g0) needed for distance sampling. We evaluated bias for N‐mixture and capture–recapture, by using simulations based on different values of detection probabilities. Finally, we conducted a power analysis to estimate the ability of the 3 methods to detect changes in Hermann's tortoise abundances. The abundance estimations we obtained using distance sampling and N‐mixture models were respectively 1.75 and 2.19 times less than those obtained using the capture–recapture method. Our results indicated thatg0was influenced by temperature variations and can differ for the same temperature on different days. Simulations showed that the N‐mixture models provide unstable estimations for species with detection probabilities <0.5, whereas capture–recapture estimations were unbiased. Power analysis showed that none of the 3 methods were precise enough to detect slow population changes. We recommend that great care should be taken when implementing monitoring designs for species with large variation in activity rates and low detection probabilities. Although N‐mixture models are easy to implement, we would not recommend using them in situations where the detection probability is very low at the risk of providing biased estimates. Among the 3 methods allowing estimation of tortoise abundances, capture–recapture should be preferred to assess population trends. © 2013 The Wildlife Society.
False negatives in thyroid cytology: Impact of large nodule size and follicular variant of papillary carcinoma
Authors: Mehanna Rania , Murphy Michael , McCarthy Julie , O'Leary Gerard , Tuthill Antoinette , Murphy Matthew S. , Sheahan Patrick
Published: January 2013

Objectives/Hypothesis

Fine‐needle aspiration (FNA) cytology is well established in the diagnosis of thyroid nodules. However, false‐negative rates for malignancy of 3% to 10% are reported. The purpose of the present study was to investigate the impact of nodule size and follicular variant of papillary carcinoma (FVPTC) on false‐negative FNA rates in thyroid nodules and on malignancy rates in nodules with indeterminate cytology.

Study Design

Retrospective study.

Methods

A total of 765 consecutive ultrasound‐guided FNAs were reviewed. Histological correlation was available in 262 cases.

Results

The overall sensitivity of FNA for malignancy was 84%, and the false‐negative rate 9.1%. Nodules ≥3 cm were significantly more likely to ultimately be diagnosed as cancer by histology than nodules <3 cm (14% vs. 6.8%, P = .006); however, they were also significantly more likely to undergo surgery than smaller nodules (P < .0001). Among the surgical series, the false‐negative rate was 10.9% in nodules ≥3 cm and 6.1% in nodules <3 cm (P = .71). Most false negatives were due to FVPTC. FVPTC was significantly more likely to be missed by preoperative cytology than conventional or other variants of papillary carcinoma (P < .001). Among cases with indeterminate cytology, nodule size and Thy‐3f versus Thy‐3a subclassification did not have any significant impact on likelihood of malignancy.

Conclusions

The sensitivity of FNA for detection of FVPTC is reduced compared to conventional papillary carcinoma. The impact of nodule size is not significant.

Level of Evidence

4.
A test method to study the change in surface topography due to running‐in of a rolling contact
Authors: Jamari J. , Schipper D.J.
Published: January 2013

A method is proposed to determine the change in surface topography during running‐in of rolling contacts. Two types of experiments have been conducted in the present work to study the running‐in of the pure rolling contact situation: repeated moving and general free rolling using a high accuracy measurement setup. The results show that the surfaces run‐in with the proposed repeated moving contact method gives a fast running‐in when compared with the general free rolling contact method. The proposed repeated moving contact method appears to be a good method to study the ideal or pure rolling contact situation because wear, as present in the general free rolling contact method, is avoided. Copyright © 2013 John Wiley & Sons, Ltd.
Unusual evolution of the magnetism on oxygen in La1−χSrχCoO3
Authors: Medling Scott , Lee Y. , Zheng H. , Mitchell J. F. , Freeland J. W. , Harmon B. N. , Bridges F.
Published: January 2013

We present X‐ray absorption spectroscopy (XAS) and X‐ray magnetic circular dichroism (XMCD) data of La1−χSrχCoO3, for χ= 0.10‐0.30, at the O K edge and then compare the results to local density approximation (LDA) and generalized gradient approximation (GGA) calculations using a 2x2x2 supercell. Increases in the XAS and XMCD are nonlinear with χ, instead appearing correlated with the overall system magnetism, which changes from glass‐like to metallic ferromagnetism around χ=0.18. The magnetic states observed in XMCD only occur at the beginning of the pre‐edge; higher energy states show no orbital moment, suggesting two distinct types of holes exist. This is consistent with the formation of ferromagnetic clusters growing with χ and eventually overlapping for χ>0.18.

Subsequent LDA and GGA calculations find a significant spin magnetic moment on O atoms (which are spinpolarized) and indicate that the doping‐induced holes are nearly equally distributed over the Co and O atoms. Calculations of the magnetization for individual O sites indicate that they are not all equivalent, but actually have different moments, depending on the proximity to Sr. This variation in the small fraction of oxygen state with angular momentum may explain in part the unusual magnetic behavior of these materials. Further, the orbitally decomposed density of states reveals that the bands from the traditional picture (localized eg and t2g states) overlap considerably and extend from ‐6 to 4 eV around E F, suggesting that the local picture is not the best for La1−χSrχCoO3 (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Missing data in clinical trials: from clinical assumptions to statistical analysis using pattern mixture models
Authors: Ratitch Bohdana , O'Kelly Michael , Tosiello Robert
Published: January 2013

The need to use rigorous, transparent, clearly interpretable, and scientifically justified methodology for preventing and dealing with missing data in clinical trials has been a focus of much attention from regulators, practitioners, and academicians over the past years. New guidelines and recommendations emphasize the importance of minimizing the amount of missing data and carefully selecting primary analysis methods on the basis of assumptions regarding the missingness mechanism suitable for the study at hand, as well as the need to stress‐test the results of the primary analysis under different sets of assumptions through a range of sensitivity analyses. Some methods that could be effectively used for dealing with missing data have not yet gained widespread usage, partly because of their underlying complexity and partly because of lack of relatively easy approaches to their implementation. In this paper, we explore several strategies for missing data on the basis of pattern mixture models that embody clear and realistic clinical assumptions. Pattern mixture models provide a statistically reasonable yet transparent framework for translating clinical assumptions into statistical analyses. Implementation details for some specific strategies are provided in an Appendix (available online as Supporting Information), whereas the general principles of the approach discussed in this paper can be used to implement various other analyses with different sets of assumptions regarding missing data. Copyright © 2013 John Wiley & Sons, Ltd.
Assessing students' understanding of inquiry: What do prospective science teachers notice?
Authors: Talanquer Vicente , Tomanek Debra , Novodvorsky Ingrid
Published: January 2013

The theoretical construct of teacher noticing has allowed mathematics teacher educators to examine teacher thinking and practice by looking at the range of activities that teachers notice in the classroom. Guided by this approach to the study of teacher thinking, the central goal of this exploratory study was to identify what prospective science teachers notice when evaluating evidence of student understanding in another teacher's inquiry‐based unit. Our results are based on the qualitative analysis of 43 prospective teachers' evaluations of assessment evidence presented to them in the form of a video case and associated written artifacts. Analysis of our data revealed two major categories of elements, Task‐General and Task‐Specific, noticed by our study participants. Task‐General elements included attention to learning objectives, independent student work, and presentation issues and they often served to guide or qualify the specific inquiry skills that were evaluated. Task‐Specific elements included the noticing of students' abilities to perform different components of an investigation. In general, study participants paid attention to important general and specific aspects of student work in the context of inquiry. However, they showed preferential attention to those process skills associated with designing an investigation versus those practices related to the analysis of data and generation of conclusions. Additionally, their interpretations of assessment outcomes were largely focused on the demonstration of general science process skills; much less attention was paid to the analysis of the epistemological validity or scientific plausibility of students' ideas. Our results provide insights into the design of meaningful learning experiences for prospective teachers that elicit, challenge, and enrich their conceptions of student understanding in the context of inquiry. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50:189–208, 2013
First language attrition
Authors: Schmid Monika S.
Published: January 2013

Speakers who live in an L2 environment for an extended period of time often experience change in the way in which they use their L1, a process referred to as L1 attrition. This article provides an overview of language attrition phenomena at various linguistic levels. However, attrition cannot be trivially or linearly related to factors such as the frequency of use of the L1. It is argued here that attrition phenomena are not the outcome of a change to the underlying linguistic system nor of access problems due to an increase in activation thresholds, but of cross‐linguistic influence in online speech production. WIREs Cogn Sci 2013, 4:117–123. doi: 10.1002/wcs.1218

This article is categorized under:

Linguistics > Language in Mind and Brain
Model‐based design of experiments for cellular processes
Authors: Chakrabarty Ankush , Buzzard Gregery T. , Rundell Ann E.
Published: January 2013

Model‐based design of experiments (MBDOE) assists in the planning of highly effective and efficient experiments. Although the foundations of this field are well‐established, the application of these techniques to understand cellular processes is a fertile and rapidly advancing area as the community seeks to understand ever more complex cellular processes and systems. This review discusses the MBDOE paradigm along with applications and challenges within the context of cellular processes and systems. It also provides a brief tutorial on Fisher information matrix (FIM)‐based and Bayesian experiment design methods along with an overview of existing software packages and computational advances that support MBDOE application and adoption within the Systems Biology community. As cell‐based products and biologics progress into the commercial sector, it is anticipated that MBDOE will become an essential practice for design, quality control, and production. WIREs Syst Biol Med 2013, 5:181–203. doi: 10.1002/wsbm.1204

This article is categorized under:

Models of Systems Properties and Processes > Cellular Models

Biological Mechanisms > Cell Signaling

Analytical and Computational Methods > Computational Methods