General Applicability (general + applicability)

Distribution by Scientific Domains

Selected Abstracts

Overview of Multiphase Flow Phenomena in Moving Time-Averaged Space

K. Ueyama
Abstract An overview of multiphase flow phenomena is described on the basis of three relations; a relation between an interaction force and time-averaged physical quantities, a relation between an interaction force and the surrounding flow field, and a relation between time-averaged physical quantities and multiphase flow. The three relations used to theoretically derive the parabolic radial distribution of gas holdup for recirculating turbulent flow in a bubble column are in good agreement with experimental data. General applicability of the three relations for a variety of multiphase flows is also discussed. [source]

Complicating Discontinuity: What About Poverty?

ABSTRACT In this article, two white science teachers at tribal schools in the Upper Midwest of the United States, who were identified by community members and school administrators as "successful" teachers, describe experiences of how they wrestle with the daily effects of generations of oppression. Most vividly, they talk about poverty. This article provides a description of some of the beliefs and attitudes, described by the teachers, that help them to be effective allies and teachers for Native American students. Their interviews offer a glimpse into the internal struggle with the contradictions of oppression. This article broadens the discussion of Native American culture-based education and raises questions for the general applicability of cultural discontinuity as an all-encompassing explanation for Native American school failure. [source]

Customer Behavior in an Online Ordering Application: A Decision Scoring Model,

Kenneth K. Boyer
ABSTRACT This research presents the development of behavioral scoring models to predict future customer purchases in an online ordering application. Internet retailing lowers many barriers for customers switching between retailers for repeat purchases; thus, retaining existing customers is a key challenge for achieving profitability. Survey data were collected from 1,089 online customers of two companies. The subjective survey data were then used to predict purchases over the ensuing 12 months based on data from the company databases. The analysis illustrates the general applicability of predictive models of future customer purchases while also demonstrating the need to develop specific models tailored for an individual company's operating and marketing environment. The models provide insight on how companies can target marketing dollars more effectively and allocate investment across multiple operational areas for maximum return. The research answers a call for rigorous research in the area of predictive marketing, an area in which many companies are excelling but where there is a scarcity of detailed knowledge regarding application of such models. [source]

Evaluating a general sediment transport model for linear incisions under field conditions

T. Vanwalleghem
Abstract Prediction of sediment transport in concentrated overland flow remains a fundamental challenge in soil erosion assessment. Sediment transport is often modelled as a non-linear function of shear stress. These relations are mostly derived from river channels or flume experiments. Here, new data of active incisions that occurred as a response to a single runoff event is presented. This allowed to complement and revisit a field-based sediment transport-shear stress equation. The results demonstrate the general applicability of the proposed relation for predicting sediment transport in linear incisions, ranging from rills to gullies, in field conditions. These findings have important implications for erosion modelling. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The intermediate effect and the diagnostic accuracy in clinical case recall of students and experts in dental medicine

J. Eberhard
Abstract Introduction:, The extensive knowledge of experts facilitates the solving of domain-specific problems. In general, this is due to the fact that experts recall more detailed information than do novices or even advanced students. However, if physicians of different expertise levels are asked to write down the details of a given case, advanced medical students recall more information than experts. This phenomenon was called the ,intermediate effect' and is considered to be a specific feature of medical expertise. The aim of the here presented study was to examine this observation in the domain of dental medicine. Materials and methods:, Sixty-one students and 20 specialised dentists participated in this study. Three clinical case descriptions were presented and afterwards the participants were told to write down all concrete information they remembered. Finally, they had to come up with a diagnosis. Interrater agreement, diagnostic accuracy and the recall explanation protocols were analysed statistically in comparison to state-of-the-art (canonical) explanations of the clinical cases. Results:, The mean interrater agreement was 96.2 ± 3.37%. It was shown statistically that the more experienced the participants, the more accurate their diagnoses were (P < 0.001). The statistical analysis using the Games-Howell test demonstrated significant more written recall of the 5th-year students compared with 3rd- and 4th-year students and experts (P < 0.05). Conclusion:, The results of this study suggest the existence of the intermediate effect in clinical case recall in dental medicine and thereby corroborate its importance and general applicability for different medical domains. [source]

Checking the Route to Cluster Helicates

Manuel R. Bermejo
Abstract The aim of the work described here was to test the general applicability of our recently reported route to cluster helicates and to carry out a systematic study to relate the structural and coordinative properties of the organic strands with the microarchitectures of the resulting cluster helicates. Nine new ZnII, CuI and AgI complexes were prepared from three Schiff base ligands [H2La: bis(4-methyl-3-thiosemicarbazone)-2,6-diacetylpyridine; H2Lb: bis(4-methyl-3-thiosemicarbazone)-2,6-diacetylbenzene; H2Lc: bis(4-ethyl-3-thiosemicarbazone)-2,6-diacetylbenzene]. The experimental data confirm that AgI and CuI tetranuclear cluster helicates were obtained with a [M4(Lx)2] stoichiometry, and this finding demonstrates the general applicability of the synthetic route. The cluster helicates presented in this work were characterized for the first time in solution by NMR spectroscopy. In addition, six of the nine complexes were characterized by X-ray diffraction studies, and three of them were found to be tetranuclear cluster helicates. A detailed study of these three crystal structures leads us to state that the changes introduced in the organic strands do not prevent the assembly of the tetranuclear cluster dihelicates, but they do affect the microarchitectures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

One size does not fit all: Managing IT employees' employment arrangements

Jayesh Prasad
As alternative employment arrangements proliferate within the information technology (IT) function, it becomes increasingly important to understand the impact of these arrangements on IT employees. A prevalent notion in the IT literature is that these employees are homogeneous in their work values and that they prefer similar employment arrangements. Given the inefficiency of designing individual employment programs, we advocate a middle ground between the two extremes of individualized employment arrangements and "one size fits all." We conducted two studies. The first study developed an individual's work values profile as a psychological construct. It used a national sample of IT employees to validate a simple, heuristic procedure that was successful in classifying about 80% of the sample into three work values profiles. The second study demonstrated the use of work values profiles for understanding how employment arrangements differentially influence employee satisfaction. It applied the validated procedure to a single organization in order to demonstrate the general applicability of the procedure and to show that it provides researchers and HR professionals with better insights than the assumption that all IT employees are alike. © 2007 Wiley Periodicals, Inc. [source]

Implications of ideas on super-hydrophobicity for water repellent soil

G. McHale
Abstract Water repellence is an important factor in soil erosion due to its role in inhibiting the re-establishment of vegetation after fire and due to its enhancement of run-off. Water repellence is studied across a range of diverse disciplines, such as chemistry, materials, textiles and soil and reclamation science. In recent years many basic studies of water repellence of materials have focused on the role of the sub-mm surface topography of a material in modifying the intrinsic hydrophobicity imparted by the surface chemistry to create super-hydrophobicity. In this report, we first illustrate the types of hydrophobic effects created by a suitable coupling of small scale surface topography with surface chemistry using three materials: an etched metal, a foam and a micro-fabricated pillar structure. These experiments demonstrate the general applicability of the ideas and suggest that they could apply to a granular material such as, a fine sandy soil, particularly when the grains have become coated with a hydrophobic layer. This applicability is confirmed by contact angle measurements of droplets of water on hydrophobic sand. A theoretical model describing the application of these ideas in a loose-packed, but regular, array of uniform spherical grains is then presented and discussed. When the grains are in a dry state initially, the effect of the surface is to increase the apparent water repellence as observed through the contact angle. However, when the spaces between the grains are filled with water, the effect is to provide greater wetting. To qualitatively confirm the enhancement of contact angle caused by the granular structure, model surfaces using 600 and 250 µm hydrophobic glass beads were created. On these surfaces, the contact angle of droplets of water was increased from 108° to 126° and 140° , respectively. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Validation of the current prognostic models for nonmetastatic renal cell carcinoma after nephrectomy in Chinese population: A 15-year single center experience

Zheng Liu
Objectives: To explore the applicability of the current prognostic models for nonmetastatic renal cell carcinoma in the Chinese population based on a single center experience. Methods: Clinical and pathological variables of 653 nonmetastatic renal cell carcinoma patients were retrospectively reviewed. Seven models were used to predict the prognosis, including the Yaycioglu model, the Cindolo model, the University of California Los Angeles Integrated Staging System model, the stage, size, grade, and necrosis model, the Kattan nomogram, the Sorbellini nomogram and the Karakiewicz nomogram. Three different end-points were used for validation, including overall survival, cancer-specific survival, and recurrence-free survival. Survival was estimated using the Kaplan,Meier method. Discriminating ability was assessed using the Harrell's concordance-index. Results: At the last follow up, 159 patients had died due to various causes, and disease recurrence occurred in 156 patients. The discriminating ability of all models was confirmed in the Chinese population. Nomograms discriminate better than algorithms, regardless of end-points. The Kattan nomogram was the most accurate, with the highest concordance-indexes of 0.752, 0.793 and 0.841 for overall survival, cancer-specific survival, and recurrence-free survival, respectively. Conclusions: The current prognostic models were developed and validated entirely based on Caucasian populations. This study defines the general applicability of the models for Chinese patients with nonmetastatic renal cell carcinoma treated with nephrectomy. The Kattan model was found to be the most accurate. The Cindolo model performed well in some situations, although only including clinical presentation and size of tumor. Therefore, models should be chosen according to different environments and purposes. [source]

One-pot synthesis of surface-functionalized molecularly imprinted polymer microspheres by iniferter-induced "living" radical precipitation polymerization

Junyi Li
Abstract This article describes for the first time the development of a new polymerization technique by introducing iniferter-induced "living" radical polymerization mechanism into precipitation polymerization and its application in the molecular imprinting field. The resulting iniferter-induced "living" radical precipitation polymerization (ILRPP) has proven to be an effective approach for generating not only narrow disperse poly(ethylene glycol dimethacrylate) microspheres but also molecularly imprinted polymer (MIP) microspheres with obvious molecular imprinting effects towards the template (a herbicide 2,4-dichlorophenoxyacetic acid (2,4-D)), rather fast template rebinding kinetics, and appreciable selectivity over structurally related compounds. The binding association constant Ka and apparent maximum number Nmax for the high-affinity sites of the 2,4-D imprinted polymer were determined by Scatchard analysis and found to be 1.18 × 104 M,1 and 4.37 ,mol/g, respectively. In addition, the general applicability of ILRPP in molecular imprinting was also confirmed by the successful preparation of MIP microspheres with another template (2-chloromandelic acid). In particular, the living nature of ILRPP makes it highly useful for the facile one-pot synthesis of functional polymer/MIP microspheres with surface-bound iniferter groups, which allows their direct controlled surface modification via surface-initiated iniferter polymerization and is thus of great potential in preparing advanced polymer/MIP materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3217,3228, 2010 [source]

Copper-coated microsprayer interface for on-line sheathless capillary electrophoresis electrospray mass spectrometry of carbohydrates

Alina D. Zamfir
Abstract A sturdy home-built sheathless CE/ESI-QTOF-MS system was developed and optimized for carbohydrate analysis. The interface and employed methodology provided a simple analytical solution to laborious CE/MS interfacing methods and to problems in characterization of complex carbohydrate mixtures that require high-resolution separation of the components. The CE/ESI interface, feasible in any MS laboratory, consists of a one-piece CE column having the CE terminus in-laboratory shaped as a microsprayer and coated with copper. The CE microsprayer was inserted into an in-house made stainless steel clenching device and the whole assembly was mounted onto a quadrupole TOF mass spectrometer. The analytical potential of the interface in terms of suitability, microsprayer performance, copper coat durability, ionization efficiency, spray stability, and sensitivity was tested first on a simple mixture of standard saccharides, which were separated, resolved, and detected with high separation efficiency. The approach was next assessed for the screening of a biological sample, a complex mixture of O -glycosylated sialylated amino acids from urine of a patient suffering from Schindler disease. Preliminary data allow this method to be considered as one of general applicability in structural glycobiology and glycomics and easy to be implemented for proteomic surveys as well. [source]

A new method for analyzing scientific productivity

John C. Huber
Previously, a new method for measuring scientific productivity was demonstrated for authors in mathematical logic and some subareas of 19th-century physics. The purpose of this article is to apply this new method to other fields to support its general applicability. We show that the method yields the same results for modern physicists, biologists, psychologists, inventors, and composers. That is, each individual's production is constant over time, and the time-period fluctuations follow the Poisson distribution. However, the productivity (e.g., papers per year) varies widely across individuals. We show that the distribution of productivity does not follow the normal (i.e., bell curve) distribution, but rather follows the exponential distribution. Thus, most authors produce at the lowest rate and very few authors produce at the higher rates. We also show that the career duration of individuals follows the exponential distribution. Thus, most authors have a very short career and very few have a long career. The principal advantage of the new method is that the detail structure of author productivity can be examined, such as trends, etc. Another advantage is that information science studies have guidance for the length of time interval being examined and estimating when an author's entire body of work has been recorded. [source]

Grain mineral concentrations and yield of wheat grown under organic and conventional management

MH Ryan
Abstract On the low-P soils in southeastern Australia, organic crops differ from conventional ones primarily in the use of relatively insoluble, as opposed to soluble, P fertilisers and in the non-use of herbicides. As organic management, particularly elimination of soluble fertilisers, is often claimed to enhance grain mineral concentrations, we examined grain from wheat on paired organic and conventional farms in two sets of experiments: (1) four pairs of commercial crops (1991,1993); and (2) fertiliser experiments on one farm pair where nil fertiliser was compared with 40 kg ha,1 of P as either relatively insoluble reactive phosphate rock or more soluble superphosphate (1991 and 1992). All wheat was grown following a 2,6 year legume-based pasture phase. Both conventional management and the superphosphate treatment greatly increased yields but reduced colonisation by mycorrhizal fungi. While only minor variations occurred in grain N, K, Mg, Ca, S and Fe concentrations, conventional grain had lower Zn and Cu but higher Mn and P than organic grain. These differences were ascribed to: soluble P fertilisers increasing P uptake but reducing mycorrhizal colonisation and thereby reducing Zn uptake and enhancing Mn uptake; dilution of Cu in heavier crops; and past lime applications on the organic farm decreasing Mn availability. These variations in grain minerals had nutritional implications primarily favouring the organic grain; however, organic management and, specifically, elimination of soluble fertilisers did not induce dramatic increases in grain mineral concentrations. In addition, organic management was coupled with yield reductions of 17,84 per cent due to P limitation and weeds. The impact of large regional variations in the characteristics of organic and conventional systems on the general applicability of the results from this study and other similar studies is discussed. Copyright © 2004 Society of Chemical Industry [source]

Supply, Factor Shares and Inflation Persistence: Re-examining Euro-area New-Keynesian Phillips Curves,

Peter McAdam
Abstract Using euro-area data, we re-examine the empirical success of New-Keynesian Phillips curves (NKPCs). We re-estimate with a suitably specified optimizing supply side (which attempts to treat non-stationarity in factor income shares and mark-ups) that allows us to derive estimates of technology parameters, marginal costs and ,price gaps'. Our resulting estimates of the euro-area NKPCs are robust, provide reasonable estimates for fixed-price durations and discount rates and embody plausible dynamic properties. Our method for identifying the underlying determinants of NKPCs has general applicability to a wide set of countries as well as of use for sectoral studies. [source]

Statistical modelling of insect behavioural responses in relation to the chemical composition of test extracts

Alan Hern
Abstract. The use of generalized linear models (GLM) for relating changes in insect behaviour to changes in the chemical composition of a plant extract is presented and applied to data from an experimental study of the olfactory response of Cydia pomonella L. (Lepidoptera: Tortricidae) to apple volatiles. The volatiles were collected from healthy apples, artificially damaged apples or apples infested with C. pomonella larvae (either instar I, IV or V). These treatments produced a blend of 23 major components and the chemical composition of the blends differed substantially amongst the treatments. A statistically significant relationship was found between the concentration of hexyl hexanoate and 2-methylbutyl acetate in each extract and the number of moths moving upwind. Statistically significant models were developed which suggested that a relationship exists between the concentration of Z,E -,-farnesene, hexyl hexanoate and 2-methylbutyl acetate and the number and duration of movements made by the moths. Subsequently Y-tube assays were carried out to validate the predictions made with respect to the orientation of mated female C. pomonella. The results of these assays confirm hexyl hexanoate as an attractant. There were indications that 2-methylbutyl acetate acted as a repellent although differences were not statistically significant. Previous bioassays have shown that C. pomonella displays a statistically significant negative linear dose,response to ,-farnesene (Hern & Dorn, 1999). The statistical methods employed are very flexible and fairly easy to implement, offering the potential to screen plant extracts for bioactive compounds with a minimum of biological constraints. Their general applicability has yet to be demonstrated and as such these analyses only offer evidence of statistical relationships; the results must be validated by additional bioassays before conclusions can be drawn. [source]

Ceric Ammonium Nitrate Initiated Grafting of PEG to Plasma Polymers for Cell-Resistant Surfaces

Naomi J. Vickers
Abstract The development of a facile method with general applicability and mild reaction conditions for grafting PEG onto surfaces to reduce bio-adhesion is described. The approach taken was to use CAN to graft PEG to plasma polymers coatings selected to give a high concentration of alcohol groups. The study showed that grafting required functional groups on surfaces, a minimum concentration of CAN initiator (0.05 M) and was time and initiator concentration dependent. Adhesion of fibroblasts and endothelial cells was reduced to negligible levels compared to the adhesion to tissue culture polystyrene and untreated plasma polymers of allyl alcohol following CAN induced PEG grafting. [source]

Protein labeling by iTRAQ: A new tool for quantitative mass spectrometry in proteome research

Sebastian Wiese
Abstract A novel, MS-based approach for the relative quantification of proteins, relying on the derivatization of primary amino groups in intact proteins using isobaric tag for relative and absolute quantitation (iTRAQ) is presented. Due to the isobaric mass design of the iTRAQ reagents, differentially labeled proteins do not differ in mass; accordingly, their corresponding proteolytic peptides appear as single peaks in MS scans. Because quantitative information is provided by isotope-encoded reporter ions that can only be observed in MS/MS spectra, we analyzed the fragmentation behavior of ESI and MALDI ions of peptides generated from iTRAQ-labeled proteins using a TOF/TOF and/or a QTOF instrument. We observed efficient liberation of reporter ions for singly protonated peptides at low-energy collision conditions. In contrast, increased collision energies were required to liberate the iTRAQ label from lysine side chains of doubly charged peptides and, thus, to observe reporter ions suitable for relative quantification of proteins with high accuracy. We then developed a quantitative strategy that comprises labeling of intact proteins by iTRAQ followed by gel electrophoresis and peptide MS/MS analyses. As proof of principle, mixtures of five different proteins in various concentration ratios were quantified, demonstrating the general applicability of the approach presented here to quantitative MS-based proteomics. [source]

Robust Design of Fault Detection and Isolation Systems

Daniele Romano
Abstract Inspired by the rationale of Robust Design, a novel methodology is presented for the design of diagnostic systems for fault detection and isolation (FDI). Detection/isolation capability and robustness, i.e. sensitivity to faults and insensitivity to noise, are addressed in an integrated way within a fully stochastic framework. Although FDI is a classical problem in control engineering, this new approach improves the current state of the art both in terms of general applicability and optimality of the design solution. It demonstrates the potential of robust design in fostering innovation in a variety of technical sectors. For illustrative purposes, the methodology is applied to the design of a FDI system for a fluid mixer. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The invariom model and its application: refinement of d,l -serine at different temperatures and resolution

B. Dittrich
Three X-ray data sets of the same d,l -serine crystal were measured at temperatures of 298, 100 and 20,K. These data were then evaluated using invarioms and the Hansen & Coppens aspherical-atom model. Multipole populations for invarioms, which are pseudoatoms that remain approximately invariant in an intermolecular transfer, were theoretically predicted using different density functional theorem (DFT) basis sets. The invariom parameters were kept fixed and positional and thermal parameters were refined to compare the fitting against the multi-temperature data at different resolutions. The deconvolution of thermal motion and electron density with respect to data resolution was studied by application of the Hirshfeld test. Above a resolution of sin,/,,,,0.55,Å,1, or d,,,0.9,Å, this test was fulfilled. When the Hirshfeld test is fulfilled, a successful modeling of the aspherical electron density with invarioms is achieved, which was proven by Fourier methods. Molecular geometry improves, especially for H atoms, when using the invariom method compared to the independent-atom model, as a comparison with neutron data shows. Based on this example, the general applicability of the invariom concept to organic molecules is proven and the aspherical density modeling of a larger biomacromolecule is within reach. [source]

The Fallacy of Generalizing from Egg Salad in False-Belief Research

Kathy Pezdek
Geraerts et al. (2008),reported that misleading individuals with false beliefs about having gotten sick on egg salad in childhood can reduce the probability of subsequently consuming egg salad. They concluded that their results ", have important implications for people's food and dieting choices," (p. 752). We argue that their conclusion represents a fundamental generalization problem. We report new findings that, together with other recent studies, data on disgust and the fact that hard boiled eggs produce a chemical associated with rotten food, suggest that Geraerts et al.'s success in reducing individuals' interest in eating egg salad is likely restricted to less appealing foods that are less frequently consumed. Because of potential applicability of their results to public health and well-being, and the more general applicability of the false-feedback paradigm to legal cases, it is important to accurately limit these conclusions and generalizations. [source]

Online identification of nonlinear multivariable processes using self-generating RBF neural networks

Karim Salahshoor
Abstract This paper addresses the problem of online model identification for multivariable processes with nonlinear and time-varying dynamic characteristics. For this purpose, two online multivariable identification approaches with self-organizing neural network model structures will be presented. The two adaptive radial basis function (RBF) neural networks are called as the growing and pruning radial basis function (GAP-RBF) and minimal resource allocation network (MRAN). The resulting identification algorithms start without a predefined model structure and the dynamic model is generated autonomously using the sequential input-output data pairs in real-time applications. The extended Kalman filter (EKF) learning algorithm has been extended for both of the adaptive RBF-based neural network approaches to estimate the free parameters of the identified multivariable model. The unscented Kalman filter (UKF) has been proposed as an alternative learning algorithm to enhance the accuracy and robustness of nonlinear multivariable processes in both the GAP-RBF and MRAN based approaches. In addition, this paper intends to study comparatively the general applicability of the particle filter (PF)-based approaches for the case of non-Gaussian noisy environments. For this purpose, the Unscented Particle Filter (UPF) is employed to be used as alternative to the EKF and UKF for online parameter estimation of self-generating RBF neural networks. The performance of the proposed online identification approaches is evaluated on a highly nonlinear time-varying multivariable non-isothermal continuous stirred tank reactor (CSTR) benchmark problem. Simulation results demonstrate the good performances of all identification approaches, especially the GAP-RBF approach incorporated with the UKF and UPF learning algorithms. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

Peripheral nerve field stimulation for pruritus relief in a patient with notalgia paraesthetica

Bernadette Ricciardo
ABSTRACT This case study is presented to exemplify the application of peripheral nerve field stimulation in the treatment of recalcitrant notalgia paraesthetica. The patient was a 60-year-old woman with severe and disabling notalgia paraesthetica. The itch persisted despite the use of several medications , topical and oral. Following a successful trial of peripheral nerve field stimulation with a temporary electrode, two subcutaneous electrodes were inserted into the affected area with a battery implanted subcutaneously in her right buttock. The patient was reviewed at 5 months post implantation. She reported a greater than 85% improvement in her itch. She also reported a major improvement in her quality of life, with particular improvement in her ability to sleep through the night. This case illustrates the possible utilization of peripheral nerve field stimulation in the treatment of notalgia paraesthetica, which is a common yet poorly understood and treated condition. Replication and controlled studies are required to determine the general applicability of this approach. [source]

Evidence from panel unit root and cointegration tests that the Environmental Kuznets Curve does not exist

Roger Perman
The Environmental Kuznets Curve (EKC) hypothesis , an inverted U-shape relation between various indicators of environmental degradation and income per capita , has become one of the ,stylised facts' of environmental and resource economics. This is despite considerable criticism on both theoretical and empirical grounds. Cointegration analysis can be used to test the validity of such stylised facts when the data involved contain stochastic trends. In the present paper, we use cointegration analysis to test the EKC hypothesis using a panel dataset of sulfur emissions and GDP data for 74 countries over a span of 31 years. We find that the data is stochastically trending in the time-series dimension. Given this, and interpreting the EKC as a long run equilibrium relationship, support for the hypothesis requires that an appropriate model cointegrates and that sulfur emissions are a concave function of income. Individual and panel cointegration tests cast doubt on the general applicability of the hypothesised relationship. Even when we find cointegration, many of the relationships for individual countries are not concave. The results show that the EKC is a problematic concept, at least in the case of sulfur emissions. [source]

Sulfated membrane adsorbers for economic pseudo-affinity capture of influenza virus particles

Lars Opitz
Abstract Strategies to control outbreaks of influenza, a contagious respiratory tract disease, are focused mainly on prophylactic vaccinations in conjunction with antiviral medications. Currently, several mammalian cell culture-based influenza vaccine production processes are being established, such as the technologies introduced by Novartis Behring (Optaflu®) or Baxter International Inc. (Celvapan). Downstream processing of influenza virus vaccines from cell culture supernatant can be performed by adsorbing virions onto sulfated column chromatography beads, such as Cellufine® sulfate. This study focused on the development of a sulfated cellulose membrane (SCM) chromatography unit operation to capture cell culture-derived influenza viruses. The advantages of the novel method were demonstrated for the Madin Darby canine kidney (MDCK) cell-derived influenza virus A/Puerto Rico/8/34 (H1N1). Furthermore, the SCM-adsorbers were compared directly to column-based Cellufine® sulfate and commercially available cation-exchange membrane adsorbers. Sulfated cellulose membrane adsorbers showed high viral product recoveries. In addition, the SCM-capture step resulted in a higher reduction of dsDNA compared to the tested cation-exchange membrane adsorbers. The productivity of the SCM-based unit operation could be significantly improved by a 30-fold increase in volumetric flow rate during adsorption compared to the bead-based capture method. The higher flow rate even further reduced the level of contaminating dsDNA by about twofold. The reproducibility and general applicability of the developed unit operation were demonstrated for two further MDCK cell-derived influenza virus strains: A/Wisconsin/67/2005 (H3N2) and B/Malaysia/2506/2004. Overall, SCM-adsorbers represent a powerful and economically favorable alternative for influenza virus capture over conventional methods using Cellufine® sulfate. Biotechnol. Bioeng. 2009;103: 1144,1154. © 2009 Wiley Periodicals, Inc. [source]

Corporate Financial Distress and Turnaround Strategies: An Empirical Analysis

Sudi Sudarsanam
Extant research on corporate turnaround from financial distress has prescribed a range of strategies to effect corporate recovery. However, no large sample study has examined the general applicability and effectiveness of these strategies. We set out to test the effectiveness of strategies and identify the underlying factors of effectiveness , the impact of timing, intensity and implementation of strategies on corporate recovery. We examine a sample of 166 potentially bankrupt UK firms drawn from 1985 to 1993 and track their turnaround strategies for a period of three years from distress. These strategies include operational, asset, managerial and financial restructuring. Our results show recovery and non-recovery firms adopt very similar sets of strategies, and managers of non-recovery firms restructure more intensively than recovery firms Nevertheless, non-recovery firms seem far less effective in strategy implementation than their recovery counterparts. Whereas recovery firms adopt growth-oriented and external-market focused strategies, non-recovery firms engage in fire-fighting strategies. [source]

Modeling of Droplet Separation Kinetics in Granular Bed Filters Based on MRI Measurements

V. van Buren
Abstract In droplet separation by granular bed filters, the transient loading regime plays an important role because, for gases with low droplet concentrations, steady state will be reached only after a long time. A mathematical model describing this transient loading regime as well as steady state was developed. It is based on differential balances for the dispersed droplets and for the separated liquid. The time-dependent and spatially resolved liquid loading is calculated and compared with data obtained by magnetic resonance imaging (MRI), a noninvasive measuring technique. The good agreement between simulated and measured loading curves proves the general applicability of the model. [source]

A Designed Well-Folded Monomeric Four-Helix Bundle Protein Prepared by Fmoc Solid-Phase Peptide Synthesis and Native Chemical Ligation,

Gunnar T. Dolphin Dr.
Abstract The design and total chemical synthesis of a monomeric native-like four-helix bundle protein is presented. The designed protein, GTD-Lig, consists of 90 amino acids and is based on the dimeric structure of the de novo designed helix-loop-helix GTD-43. GTD-Lig was prepared by the native chemical ligation strategy and the fragments (45 residues long) were synthesized by applying standard fluorenylmethoxycarbonyl (Fmoc) chemistry. The required peptide,thioester fragment was prepared by anchoring the free ,-carboxy group of Fmoc-Glu-allyl to the solid phase. After chain elongation the allyl moiety was orthogonally removed and the resulting carboxy group was functionalized with a glycine,thioester followed by standard trifluoroacetic acid (TFA) cleavage to produce the unprotected peptide,thioester. The structure of the synthetic protein was examined by far- and near-UV circular dichroism (CD), sedimentation equilibrium ultracentrifugation, and NMR and fluorescence spectroscopy. The spectroscopic methods show a highly helical and native-like monomeric protein consistent with the design. Heat-induced unfolding was studied by tryptophan absorbance and far-UV CD. The thermal unfolding of GTD-Lig occurs in two steps; a cooperative transition from the native state to an intermediate state and thereafter by noncooperative melting to the unfolded state. The intermediate exhibits the properties of a molten globule such as a retained native secondary structure and a compact hydrophobic core. The thermodynamics of GuHCl-induced unfolding were evaluated by far-UV CD monitoring and the unfolding exhibited a cooperative transition that is well-fitted by a two-state mechanism from the native to the unfolded state. GTD-Lig clearly shows the characteristics of a native protein with a well-defined structure and typical unfolding transitions. The design and synthesis presented herein is of general applicability for the construction of large monomeric proteins. [source]

A Close Look at Fluorescence Quenching of Organic Dyes by Tryptophan

CHEMPHYSCHEM, Issue 11 2005
Sören Doose Dr.
Abstract Understanding fluorescence quenching processes of organic dyes by biomolecular compounds is of fundamental importance for in-vitro and in-vivo fluorescence studies. It has been reported that the excited singlet state of some oxazine and rhodamine derivatives is efficiently and almost exclusively quenched by the amino acid tryptophan (Trp) and the DNA base guanine via photoinduced electron transfer (PET). We present a detailed analysis of the quenching interactions between the oxazine dye MR121 and Trp in aqueous buffer. Steady-state and time-resolved fluorescence spectroscopy, together with fluorescence correlation spectroscopy (FCS), reveal three contributing quenching mechanisms: 1) diffusion-limited dynamic quenching with a bimolecular quenching rate constant kdof 4.0×109s,1,M,1, 2) static quenching with a bimolecular association constant Ksof 61,M,1, and 3) a sphere-of-action contribution to static quenching described by an exponential factor with a quenching constant , of 22,M,1. The latter two are characterized as nonfluorescent complexes, formed with ,30,% efficiency upon encounter, that are stable for tens of nanoseconds. The measured binding energy of 20,30 kJmol,1is consistent with previous estimates from molecular dynamics simulations that proposed stacked complexes due to hydrophobic forces. We further evaluate the influence of glycerol and denaturant (guanidine hydrochloride) on the formation and stability of quenched complexes. Comparative measurements performed with two other dyes, ATTO 655 and Rhodamine 6G show similar results and thus demonstrate the general applicability of utilizing PET between organic dyes and Trp for the study of conformational dynamics of biopolymers on sub-nanometer length and nanosecond time-scales. [source]

Recovery and Reuse of Nanoparticles by Tuning Solvent Quality

Olesya Myakonkaya
Nanoparticles Are Forever: An isothermal low-energy approach permits recovery of nanoparticles for reuse by tuning solvent quality. The recovered and redispersed nanoparticles retain their morphology and chemical reactivity for recycle and reuse. The method, shown here to be effective in the application of nanoparticles as catalysts, will have a wide and general applicability. [source]