bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring the interactions between gold nanoparticles and analytes through surface‐assisted laser desorption/ionization mass spectrometry
Authors: Lin Yang‐Wei , Chen Wen‐Tsen , Chang Huan‐Tsung 
Published: March 2010

AbstractSurface‐assisted laser desorption/ionization mass spectrometry (SALDI‐MS) is applied to provide strong evidence for the chemical reactions of functionalized gold nanoparticles (Au NPs) with analytes – Hg2+ ions induced MPA−Au NPs aggregation in the presence of 2,6‐pyridinedicarboxylic acid (PDCA) and H2O2 induced fluorescence quenching of 11‐MUA−Au NDs. PDCA‐Hg2+‐MPA coordination is responsible for Au NPs aggregation, while the formation of 11‐MUA disulfide compounds that release into the bulk solution is responsible for H2O2‐induced fluorescence quenching. In addition to providing information about the chemical structures, SALDI‐MS is also selective and sensitive for the detection of Hg2+ ions and H2O2. The limits of detection (LODs) for Hg2+ ions and H2O2 by SALDI‐MS were 300 nM and 250 µM, respectively. The spot‐to‐spot variations in the two studies were both less than 18% (50 sample spots). Our results reveal that SALDI‐MS can be used to study analyte‐induced changes in the surface properties of nanoparticles. Copyright © 2010 John Wiley & Sons, Ltd.
A clean‐up technology for the simultaneous determination of lysophosphatidic acid and sphingosine‐1‐phosphate by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry using a phosphate‐capture molecule, Phos‐tag
Authors: Morishige Jun‐ichi , Urikura Mai , Takagi Haruko , Hirano Kaoru , Koike Tohru , Tanaka Tamotsu , Satouchi Kiyoshi 
Published: March 2010

AbstractLysophosphatidic acid (LPA) and sphingosine‐1‐phosphate (S1P) are growth factor‐like lipids having a phosphate group. The concentrations of these mediator lipids in blood are considered to be potential biomarkers for early detection of cancer or vascular diseases. Here, we report a method for simultaneous determination of LPA and S1P using Phos‐tag, a zinc complex that specifically binds to a phosphate‐monoester group. Although both LPA and S1P are hydrophilic compounds, we found that they acquire hydrophobic properties when they form complexes with Phos‐tag. Based on this finding, we developed a method for the enrichment of LPA and S1P from biological samples. The first partition in a two‐phase solvent system consisting of chloroform/methanol/water (1:1:0.9, v/v/v) is conducted for the removal of lipids. LPA and S1P are specifically extracted as Phos‐tag complexes at the second partition by adding Phos‐tag. The Phos‐tag complexes of LPA and S1P are detectable by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and quantifiable based on the relative intensities of ions using 17:0 LPA and C17 S1P as internal standards. The protocol was validated by analyses of these mediator lipids in calf serum, a rat brain and a lung. The clean‐up protocol is rapid, requires neither thin‐layer chromatography (TLC) nor liquid chromatography (LC), and is applicable to both blood and solid tissue samples. We believe that our protocol will be useful for a routine analysis of LPA and S1P in many clinical samples. Copyright © 2010 John Wiley & Sons, Ltd.
Hydrogen/deuterium exchange on aromatic rings during atmospheric pressure chemical ionization mass spectrometry
Authors: Davies Noel W. , Smith Jason A. , Molesworth Peter P. , Ross John J. 
Published: March 2010

AbstractIt has been demonstrated that substituted indoles fully labelled with deuterium on the aromatic ring can undergo substantial exchange back to partial and even fully protonated forms during atmospheric pressure chemical ionisation (APCI) liquid chromatography/mass spectrometry (LC/MS). The degree of this exchange was strongly dependent on the absolute quantity of analyte, the APCI desolvation temperature, the nature of the mobile phase, the mobile phase flow rate and the instrument used. Hydrogen/deuterium (H/D) exchange on several other aromatic ring systems during APCI LC/MS was either undetectable (nitrobenzene, aniline) or extremely small (acetanilide) compared to the effect observed for substituted indoles. This observation has major implications for quantitative assays using deuterium‐labelled internal standards and for the detection of deuterium‐labelled products from isotopically labelled feeding experiments where there is a risk of back exchange to the protonated form during the analysis. Copyright © 2010 John Wiley & Sons, Ltd.
The production of entrepreneurial opportunity: a constructivist perspective
Authors: Wood Matthew S. , McKinley William 
Published: March 2010

AbstractThis article presents a conceptual model of entrepreneurial opportunity production from a constructivist perspective. The model assumes that opportunity production proceeds through several stages, including conceptualization of an opportunity idea by an entrepreneur, objectification of that idea, and enactment of the opportunity into a new venture. However, not all opportunity ideas survive this full process. Between the conceptualization stage and the objectification stage, some ideas are abandoned due to inadequate objectification. Also, between the objectification stage and the enactment stage, some objectified opportunities are abandoned due to insufficient resource support. We identify variables that influence the likelihood that opportunity ideas will be objectified and other variables that influence the likelihood that objectified opportunities will be enacted, and these variables are incorporated into empirically testable propositions. In the discussion section, we describe several boundary conditions for our theory, contrast the theory with objectivist (discovery) theory, and derive implications for future research. Copyright © 2010 Strategic Management Society.
Estimating the crude probability of death due to cancer and other causes using relative survival models
Authors: Lambert P. C. , Dickman P. W. , Nelson C. P. , Royston P. 
Published: March 2010

AbstractRelative survival is used extensively in population‐based cancer studies to measure patient survival correcting for causes of death not related to the disease of interest. An advantage of relative survival is that it provides a measure of mortality associated with a particular disease, without the need for information on cause of death. Relative survival provides a measure of net mortality, i.e. the probability of death due to cancer in the absence of other causes. This is a useful measure, but it is also of interest to measure crude mortality, i.e. the probability of death due to cancer in the presence of other causes. A previous approach to estimate the crude probability of death in population‐based cancer studies used life table methods, but we show how the estimates can be obtained after fitting a relative survival model. We adopt flexible parametric models for relative survival, which use restricted cubic splines for the baseline cumulative excess hazard and for any time‐dependent effects. We illustrate the approach using an example of men diagnosed with prostate cancer in England and Wales showing the differences in net and crude survival for different ages. Copyright © 2010 John Wiley & Sons, Ltd.
Checking consistency in mixed treatment comparison meta‐analysis
Authors: Dias S. , Welton N. J. , Caldwell D. M. , Ades A. E. 
Published: March 2010

AbstractPooling of direct and indirect evidence from randomized trials, known as mixed treatment comparisons (MTC), is becoming increasingly common in the clinical literature. MTC allows coherent judgements on which of the several treatments is the most effective and produces estimates of the relative effects of each treatment compared with every other treatment in a network.We introduce two methods for checking consistency of direct and indirect evidence. The first method (back‐calculation) infers the contribution of indirect evidence from the direct evidence and the output of an MTC analysis and is useful when the only available data consist of pooled summaries of the pairwise contrasts. The second more general, but computationally intensive, method is based on ‘node‐splitting’ which separates evidence on a particular comparison (node) into ‘direct’ and ‘indirect’ and can be applied to networks where trial‐level data are available. Methods are illustrated with examples from the literature. We take a hierarchical Bayesian approach to MTC implemented using WinBUGS and R.We show that both methods are useful in identifying potential inconsistencies in different types of network and that they illustrate how the direct and indirect evidence combine to produce the posterior MTC estimates of relative treatment effects. This allows users to understand how MTC synthesis is pooling the data, and what is ‘driving’ the final estimates.We end with some considerations on the modelling assumptions being made, the problems with the extension of the back‐calculation method to trial‐level data and discuss our methods in the context of the existing literature. Copyright © 2010 John Wiley & Sons, Ltd.
On the prognostic value of survival models with application to gene expression signatures
Authors: Hielscher T. , Zucknick M. , Werft W. , Benner A. 
Published: March 2010

AbstractAs part of the validation of any statistical model, it is a good statistical practice to quantify the prediction accuracy and the amount of prognostic information represented by the model; this includes gene expression signatures derived from high‐dimensional microarray data. Several approaches exist for right‐censored survival data measuring the gain in prognostic information compared with established clinical parameters or biomarkers in terms of explained variation or explained randomness. They are either model‐based or use estimates of prediction accuracy.As these measures differ in their underlying mechanisms, they vary in their interpretation, assumptions and properties, in particular in how they deal with the presence of censoring. It remains unclear, under what conditions and to what extent they are comparable. We present a comparison of several common measures and illustrate their behaviour in high‐dimensional situations in simulation examples as well as in applications to real gene expression microarray data sets. An overview of available software implementations in R is given. Copyright © 2010 John Wiley & Sons, Ltd.
Statistical models for heart rate correction of the QT interval
Authors: Ring Arne 
Published: March 2010

AbstractThe analysis of QT interval data is now an essential part of the assessment of drug safety. As the QT interval is inversely associated with heart rate, an appropriate correction must be applied in order to evaluate QT data in clinical trials. The aim is to characterize changes in QT interval at a standard heart rate, taking into account the correlation between these two variables to adjust for heart rate changes during the course of the trial. It has been shown that the relationship between the RR interval (=1/heart rate) and the QT interval is highly variable between individuals but stable over time within each individual.Many mathematical models have been developed to describe the QT–RR relationship. However, there has been less emphasis on the derivation of suitable statistical models that account for the multilevel structure of the ECG data.An important example is the interpretation of the so‐called population‐specific heart rate corrections, which are based on data pooled from different subjects. Often, simple regression techniques are used to quantify the population correction, disregarding the subject level and leading to biased parameter estimates. Instead, population‐based corrections that account for individual intercepts should be used, in order to distinguish within‐subject‐effects from between‐subject effects. Therefore, population‐specific corrections cannot be derived solely from the cross‐sectional data. The impact of the different statistical models is illustrated by data from the baseline periods of six clinical QT studies. Copyright © 2010 John Wiley & Sons, Ltd.
Burnout as an important factor in the psychophysiological responses to a work day in Teachers
Authors: Moya‐Albiol Luis , Serrano Miguel Ángel , Salvador Alicia 
Published: March 2010

AbstractBurnout syndrome is an important psychosocial risk in the job context, especially in professions with a strong social interaction, as in the case of teaching. This study analyses the role of burnout in the psychophysiological responses to a work day in teachers. High burnout was related to worse mood, and higher perceived stress throughout the work day. Moreover, burnout is positively related to systolic blood pressure and negatively related to salivary cortisol levels at the beginning of the work day. Higher scores of burnout in teachers are also related to lower heart rate in the middle of the work day. The psychophysiological responses to a work day are specifically associated with the different burnout subscales (emotional exhaustion, depersonalization and personal accomplishment). Men presented higher diastolic blood pressure than women at the beginning and the middle of the work day. Burnout could induce an alteration in mood together with a dysregulation of the cardiovascular activity and the hypothalamo‐pituitary‐adrenocortical axis functioning in response to a work day in teachers. Moreover, our results offer different burnout‐dependent patterns of relationships between psychological, cardiovascular and cortisol responses, and they suggest that gender plays a moderator role in the cardiovascular response to a work day. Copyright © 2010 John Wiley & Sons, Ltd.
Entrepreneurial finance meets organizational reality: comparing investment practices and performance of corporate and independent venture capitalists
Authors: Dushnitsky Gary , Shapira Zur 
Published: March 2010

AbstractThis paper investigates the effect of compensation of corporate personnel on their investment in new technologies. We focus on a specific corporate activity, namely corporate venture capital (CVC), describing minority equity investment by established‐firms in entrepreneurial ventures. The setting offers an opportunity to compare corporate investors to investment experts, the independent venture capitalists (IVCs). On average, we observe a performance gap between corporate investors and their independent counterparts. Interestingly, the performance gap is sensitive to CVCs' compensation scheme: it is the largest when CVC personnel are awarded performance pay. Not only do we study the association between incentives and performance but we also document a direct relationship between incentives and the actions managers undertake. For example, we observe disparity between the number of participants in venture capital syndicates that involve a corporate investor, and those that consist solely of IVCs. The disparity shrinks substantially, however, for a subset of CVCs that compensate their personnel using performance pay. We find a parallel pattern when analyzing the relationship between compensation and another investment practice, staging of investment. To conclude, the paper investigates the three elements of the principal‐agent framework, thus providing direct evidence that compensation schemes (incentives) shape investment practices (managerial action), and ultimately investors' outcome (performance). Copyright © 2010 John Wiley & Sons, Ltd.
‘Keep out’ signs: the role of deterrence in the competition for resources
Authors: Clarkson Gavin , Toh Puay Khoon 
Published: March 2010

AbstractTo explain resource heterogeneity, past research focuses on how rivals' resources are hidden from firms and firms accordingly have difficulties accessing them. We argue that resource heterogeneity may also arise when firms are deterred from a technological space upon being shown what resources rivals already possess within that space. To illustrate this deterrence effect, we use patent reexamination certificates, which indicate strategic stakes within a technological space without materially disclosing additional details of the underlying technologies and hence avoid the confounding effect of attracting competition through disclosure. We demonstrate how rivals' reexamination certificates within a technological space induce a firm to subsequently allocate less inventive effort in that space, based on two mechanisms—indications of rivals' developmental speed and exclusionary ability. We further develop these two mechanisms by arguing that the deterrence effect is stronger when rivals' speed is enhanced by their downstream capabilities, or when rivals' exclusion is enhanced by their litigation experiences. Findings suggest that a firm's path of resource accumulation evolves through avoidance of rivals' paths, and deterrence may constitute a viable alternative theory of resource heterogeneity. Copyright © 2010 John Wiley & Sons, Ltd.
Label‐Free Attomolar Detection of Proteins Using Integrated Nanoelectronic and Electrokinetic Devices
Authors: Gong Jian‐Ru 
Published: March 2010

AbstractHigh‐sensitivity screening of biomarkers is critical to areas ranging from early disease detection and diagnosis to bioterrorism surveillance. Here the development of integrated nanoelectronic and electrokinetic devices for label‐free attomolar detection of proteins is reported. Electrically addressable silicon nanowire field‐effect transistors and electrodes for electrokinetic transport are integrated onto a common sensor chip platform, and the nanowire devices are subsequently functionalized with receptors for selective biomarker detection. Nanowire devices modified with monoclonal antibody for prostate specific antigen exhibit close to a 104 increase in sensitivity due to streaming dielectrophoresis and corresponding electrostatic contribution to the binding affinity after application of an AC electric field. The devices are also modified with receptors for cholera toxin subunit B and achieve a similar enhancement. These results show general applicability of this method, and could open up opportunities in early stage disease detection and the analysis of proteins from single cells.
Eine Integrierte Methode für die Sicherheitsbewertung von Glasbauteilen
Authors: Bos Freek Paul 
Published: March 2010

AbstractDie bestehenden Methoden zur Sicherheitsbewertung von Glaskonstruktionen sind unzureichend. Es fehlen identifizierbare Bauteil‐Sicherheits‐Eigenschaften. Die Folge sind Diskussionen und Unsicherheiten in der Ingenieurpraxis. Ziel der Integrierten Methode für die Sicherheitsbewertung von Glasbauteilen ist die Schaffung objektiver Kriterien für den Vergleich von Glaskonstruktionen hinsichtlich ihrer Sicherheit. Dafür werden vier Eigenschaften von Glaskonstruktionen definiert: Widerstand, Schadensanfälligkeit, Redundanz und Bruchart. Diese sind graphisch im Bauteilsicherheitsdiagramm zusammengefasst. Es werden ebenso unterschiedliche, zugrunde liegende Konzepte, vorgestellt, die es erlauben, das Leistungsvermögen so zu definieren, dass jede einzelne Bauteil‐Sicherheits‐Eigenschaft geprüft werden kann.An Integrated Approach to Structural Glass Safety. Existing methods to asses the safety of structural glass elements are insufficient. There is a lack of identifiable element safety properties. As a result, there is much confusion and discussion in professional practice. In an attempt to obtain objective criteria to compare structural glass designs with regard to safety, the Integrated Approach to Structural Glass Safety is proposed. Four properties of the glass elements are defined: resistance, damage sensitivity, redundancy and fracture mode. They are graphically combined in the element safety diagram. Several underlying concepts are also introduced, so that performance requirements can be formulated to which each element safety property can be checked.
Interaktion Gleis/Brücke – Stand der Technik und Beispiele
Authors: Freystein Hartmut 
Published: March 2010

AbstractDie Wahl einer geeigneten Brücke sowie die Konstruktion und die Bemessung von Eisenbahnbrücken werden maßgeblich beeinflusst von der Interaktion zwischen dem Oberbau und der Brücke aufgrund der Einwirkungen aus dem Eisenbahnverkehr (Anfahren, Bremsen und LM 71) sowie Temperaturschwankungen. Wesentliche Parameter auf Bauwerksseite sind die Oberbauart, die Ausgleichs‐ und Dehnlängen des Überbaus, die Unterbausteifigkeit, die Übergangskonstruktion sowie die Bauweise. Während in den meisten Fällen vereinfachte Bemessungsverfahren zum Einsatz kommen, müssen in schwierigen Fällen aufwändige Berechnungsverfahren durchgeführt werden. In diesem Beitrag werden die technischen Hintergründe und der Stand der Technik mit einem Ausblick auf Weiterentwicklungen aufgezeigt.Track/Bridge‐Interaction – State of the art and examples. Track/Bridge‐Interaction significantly influences the choice of bridge‐systems, the construction and calculation because of the actions due to rail traffic (braking and acceleration, LM 71) and changes of temperature. Main parameters with regard to the construction are the track superstructure, expansion length of bridge superstructure, support stiffness, transitions structures for bridges and the bridge design. Whereas in the majority of cases simplified calculation methods are sufficient, in certain difficult cases special and complex calculation methods are necessary. This article demonstrates the technical background and the state of the art with a perspective to further developments.
Geklebte Ganzglaskonstruktion für das Leibniz‐Institut für Festkörper‐ und Werkstoffforschung in Dresden
Authors: Weller Bernhard , Döbbel Florian , Nicklisch Felix , Prautzsch Volker , Rücker Sebastian 
Published: March 2010

AbstractDie historischen Drucktanks der neuen Heliumverflüssigungsanlage des Leibniz‐Instituts für Festkörper‐ und Werkstoffforschung in Dresden präsentieren sich der Öffentlichkeit in einer in Deutschland bisher einmaligen Ganzglaskonstruktion. Die Vision einer gläsernen Hülle ohne störende metallische Verbindungsmittel konnte von der Idee bis hin zum fertigen Bauwerk verwirklicht werden. Vier gläserne Rahmen, in den Ecken durch transparente Klebungen gefügt, tragen die äußere Hülle der Glasbox. Der Ausführung gingen umfangreiche theoretische und experimentelle Untersuchungen zum Tragverhalten und zur Herstellungstechnologie voraus und bildeten die Grundlage für die notwendige Zustimmung im Einzelfall.All Glass Enclosure for the Leibniz Institute for Solid State and Material Research in Dresden. The pressure tanks – components of historic value – for the recently installed helium liquefaction unit at the Leibniz Institute for Solid State and Materials Research in Dresden are displayed in an all glass enclosure which has been produced for the first time in Germany. The idea of a transparent structure with no distracting bolts or clamps was developed from vision to final solution. Four glass frames joined by transparent adhesives at their corners support the outer walls and ceiling of the glass box. Substantial theoretical and experimental studies of the structural behaviour and the manufacturing technology were required for the approval by the building authorities.