One Example (one + example)

Distribution by Scientific Domains


Selected Abstracts


Meetings Across the Paradigmatic Divide

EDUCATIONAL PHILOSOPHY AND THEORY, Issue 3 2007
Peter Moss
Abstract The problematique addressed by the article is the growth of a dominant discourse in early childhood education and care, which has a strong effect on policy and practice, paralleled by an increasing number of other discourses which problematise most of the values, assumptions and understandings of the former. Yet there is very little engagement between these discourses, in large part because they are situated within different paradigms,modernity in the former case, postfoundationalism in the latter. The author argues that the absence of dialogue and debate impoverishes early childhood and weakens democratic practice. The article considers whether and in what conditions the concept of agonistic pluralism might provide a framework for political engagement among at least some on either side of the paradigmatic divide, and takes evaluation as one example of a subject for an agonistic politics of early childhood. [source]


Directly Heated Bismuth Film Electrodes Based on Gold Microwires

ELECTROANALYSIS, Issue 13 2010
Martin Jacobsen
Abstract As a nontoxic substitute for mercury electrodes, bismuth electrodes attained a lot of attention during the last years. In this report we describe for the first time the preparation of two different directly heatable bismuth-modified microwire electrodes. We characterized the electrochemical behaviour using cyclic voltammetry in acetate buffer and alkaline tartrate solution. The bismuth electrodes show a significantly wider potential window compared with bare gold wires. In the presence of picric acid as one example for the detection of explosives, the bismuth electrodes deliver higher signals. By applying heat during the measurements, the signals can be enhanced further. We used the temperature pulse amperometry (TPA) technique to improve the electrochemical response at the different types of electrodes. In this preliminary study, we were able to detect 3,ppm traces of picric acid. [source]


The Intramolecular Aromatic Electrophilic Substitution of Aminocyclopropanes Prepared by the Kulinkovich,de Meijere Reaction,

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2005
Laurent Larquetoux
Abstract This article describes new examples of intramolecular Kulinkovich,de Meijere reactions applied to carboxylic amides bearing an olefin moiety and an aromatic ring at a suitable position. Upon heating, the aminocyclopropanes thus obtained undergo intramolecular aromatic electrophilic substitution to afford polycyclic systems. Among the various starting materials prepared, best results are obtained from indole and phenol derivatives. In each case, a benzylic quaternary centre is introduced at the newly-formed ring junction. On one example, the efficiency of the cyclisation has been dramatically improved using a catalytic amount of para -toluenesulfonic acid. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]


Large-Scale Synthesis of Long Crystalline Cu2-xSe Nanowire Bundles by Water-Evaporation-Induced Self-Assembly and Their Application in Gas Sensing

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2009
Jun Xu
Abstract By a facile water evaporation process without adding any directing agent, Cu2-xSe nanowire bundles with diameters of 100,300,nm and lengths up to hundreds of micrometers, which comprise crystalline nanowires with diameters of 5,8,nm, are obtained. Experiments reveal the initial formation/stacking of CuSe nanoplates and the subsequent transformation to the Cu2-xSe nanowire bundles. A water-evaporation-induced self-assembly (WEISA) mechanism is proposed, which highlights the driving force of evaporation in promoting the nanoplate stacking, CuSe-to-Cu2-xSe transformation and the growth/bundling of the Cu2-xSe nanowires. The simplicity, benignancy, scalability, and high-yield of the synthesis of this important nanowire material herald its numerous applications. As one example, the use of the Cu2-xSe nanowire bundles as a photoluminescence-type sensor of humidity is demonstrated, which shows good sensitivity, ideal linearity, quick response/recovery and long lifetime in a very wide humidity range at room temperature. [source]


A practical grid-based method for tracking multiple refraction and reflection phases in three-dimensional heterogeneous media

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2006
M. De Kool
SUMMARY We present a practical grid-based method in 3-D spherical coordinates for computing multiple phases comprising any number of reflection and transmission branches in heterogeneous layered media. The new scheme is based on a multistage approach which treats each layer that the wave front enters as a separate computational domain. A finite-difference eikonal solver known as the fast-marching method (FMM) is reinitialized at each interface to track the evolving wave front as either a reflection back into the incident layer or a transmission through to the adjacent layer. Unlike the standard FMM, which only finds first arrivals, this multistage approach can track those later arriving phases explicitly caused by the presence of discontinuities. Notably, the method does not require an irregular mesh to be constructed in order to connect interface nodes to neighbouring velocity nodes which lie on a regular grid. To improve accuracy, local grid refinement is used in the neighbourhood of a source point where wave front curvature is high. The method also provides a way to trace reflections from an interface that are not the first arrival (e.g. the global PP phase). These are computed by initializing the multistage FMM from both the source and receiver, propagating the two wave fronts to the reflecting interface, and finding stationary points of the sum of the two traveltime fields on the reflecting interface. A series of examples are presented to test the efficiency, accuracy and robustness of the new scheme. As well as efficiently computing various global phases to an acceptable accuracy through the ak135 model, we also demonstrate the ability of the scheme to track complex crustal phases that may be encountered in coincident reflection, wide-angle reflection/refraction or local earthquake surveys. In one example, a variety of phases are computed in the presence of a realistic subduction zone, which includes several layer pinch-outs and a subducting slab. Our numerical tests show that the new scheme is a practical and robust alternative to conventional ray tracing for finding various phases in layered media at a variety of scales. [source]


Reactions of 2-Unsubstituted 1H -Imidazole 3-Oxides with 2,2-Bis(trifluoromethyl)ethene-1,1-dicarbonitrile: A Stepwise 1,3-Dipolar Cycloaddition

HELVETICA CHIMICA ACTA, Issue 7 2006
Grzegorz Mlosto
Abstract The reaction of 1,4,5-trisubstituted 1H -imidazole-3-oxides 1 with 2,2-bis(trifluoromethyl)ethene-1,1-dicarbonitrile (7, BTF) yielded the corresponding 1,3-dihydro-2H -imidazol-2-ones 10 and 2-(1,3-dihydro-2H -imidazol-2-ylidene)malononitriles 11, respectively, depending on the solvent used. In one example, a 1,:,1 complex, 12, of the 1H -imidazole 3-oxide and hexafluoroacetone hydrate was isolated as a second product. The formation of the products is explained by a stepwise 1,3-dipolar cycloaddition and subsequent fragmentation. The structures of 11d and 12 were established by X-ray crystallography. [source]


Organizational entrepreneurship: Theoretical background, some empirical tests, and directions for future research

HUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2005
Mariusz Bratnicki
The widely held contemporary perspective on entrepreneurship is dangerously premature. Currently existing theories are insufficient to understand the dynamic interplay among entrepreneurship, the state, and external environment forces, as well as the organization's capacity to facilitate entrepreneurship and resulting effectiveness. In this exploratory paper I identify organizational architecture variables that help to shape a firm's entrepreneurship. The topic of organizational enablers is introduced. The primary purpose of the investigation falls under a category of exploration of dialectics' potential for entrepreneurship theory and development concept that refers to strategic contradictions, organizational enablers, and entrepreneurial behaviors. In particular, it focuses on understanding the organizational context of entrepreneurship and understanding the entrepreneurial reconciliation made by managers who seek to increase their company's growth. I investigate empirically how reconciliation of primary and secondary contradictions is related to entrepreneurial behaviors. The in-depth examination of organizational enablers and entrepreneurial behavior is only one example of how a dialectical approach can reshape our understanding of the complex, multilevel entrepreneurship process, which may have less to do with the behavior of individual members than with impersonal and seemingly insignificant forces. Finally, implications for future research are discussed. © 2005 Wiley Periodicals, Inc. Hum Factors Man 15: 15,33, 2005. [source]


Cutting through the statistical fog: understanding and evaluating non-inferiority trials

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 10 2010
W. S. Weintraub
Summary Every year, results from many important randomised, controlled trials are published. Knowing the elements of trial design and having the skills to critically read and incorporate results are important to medical practitioners. The goal of this article is to help physicians determine the validity of trial conclusions to improve patient care through more informed medical decision making. This article includes a review of 162 randomised, controlled non-inferiority (n = 116) and equivalence (n = 46) hypothesis studies as well as the larger Stroke Prevention using Oral Thrombin Inhibitor in atrial Fibrillation V study and the Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial. Evaluation of data from small and large trials uncovers significant flaws in design and models employed and uncertainty about calculations of statistical measures. As one example of questionable study design, discussion includes a large (n = 3922), double-blind, randomised, multicentre trial comparing the efficacy of ximelagatran with warfarin for prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation and additional stroke risk factors. Investigators concluded that ximelagatran was effective compared with well-controlled warfarin for prevention of thromboembolism. However, deficiencies in design, as well as concerns about liver toxicity, resulted in the rejection of the drug by the US Food and Drug Administration. Many trials fail to follow good design principles, resulting in conclusions of questionable validity. Well-designed non-inferiority trials can provide valuable data and demonstrate efficacy for beneficial new therapies. Objectives and primary end-points must be clearly stated and rigorous standards met for sample size, establishing the margin, patient characteristics and adherence to protocol. [source]


The Venturesome Economy: How Innovation Sustains Prosperity in a More Connected World,

JOURNAL OF APPLIED CORPORATE FINANCE, Issue 1 2009
Amar Bhidé
Many observers have warned that the next stage of globalization,the offshoring of research and development to China and India,threatens the foundations of Western prosperity. But in this article, the author explains why the doomsayers are likely to be wrong. Using extensive field studies on venture capital-backed businesses to examine how technology is really used to create value in modern economies, this article explains how and why scientific advances abroad generally contribute to prosperity at home, and why trying to maintain the U.S. lead by subsidizing more research or training more scientists is likely to do more harm than good. When breakthrough ideas have no borders, a nation's capacity to exploit cutting-edge research regardless of where it originates is the key to its economic competitiveness. "Venturesome consumption",that is, the willingness and ability of businesses and consumers to use products and technologies derived from scientific research in the most effective ways,is far more important than having a share of the research. And for this reason, well-developed and "venturesome" economies like the U.S. benefit disproportionately from scientific innovations abroad. To cite just one example discussed at length in this article, the success of Apple's iPod owes much to technologies that were developed largely in Asia and Europe. The proven ability of the United States to remain at the forefront of the global "innovation game" reflects the contributions of many players,not just a few brilliant scientists and engineers, but literally millions of U.S. entrepreneurs, managers, financiers, salespersons, and, to a very large degree, U.S. consumers. As long as their venturesome spirit remains alive and well, advances abroad should not be feared but welcomed. [source]


Ambiguous Loss Research, Theory, and Practice: Reflections After 9/11

JOURNAL OF MARRIAGE AND FAMILY, Issue 3 2004
Pauline Boss
This article contains an overview of three decades of research, theory development, and clinical application about ambiguous loss. Although the work includes both physical and psychological types of ambiguous loss, the focus is the aftermath of 9/11 (September 11, 2001), when the World Trade Center collapsed following terrorist attacks. On the basis of her previous work, the author was asked to design an intervention for families of the missing. She reflects on what she learned from this unexpected test and presents new propositions and hypotheses to stimulate further research and theory that is more inclusive of diversity. She suggests that scholars should focus more on universal family experience. Ambiguous loss is just one example. Encouraging researchers and practitioners to collaborate in theory development, she concludes that research-based theory is essential to inform interventions in unexpected times of terror, and in everyday life. [source]


Efficient recognition of protein fold at low sequence identity by conservative application of Psi-BLAST: application,

JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2005
F. J. Stevens
Abstract Based on a study involving structural comparisons of proteins sharing 25% or less sequence identity, three rounds of Psi-BLAST appear capable of identifying remote evolutionary homologs with greater than 95% confidence provided that more than 50% of the query sequence can be aligned with the target sequence. Since it seems that more than 80% of all homologous protein pairs may be characterized by a lack of significant sequence similarity, the experimental biologist is often confronted with a lack of guidance from conventional homology searches involving pair-wise sequence comparisons. The ability to disregard levels of sequence identity and expect value in Psi-BLAST if at least 50% of the query sequence has been aligned allows for generation of new hypotheses by consideration of matches that are conventionally disregarded. In one example, we suggest a possible evolutionary linkage between the cupredoxin and immunoglobulin fold families. A thermostable hypothetical protein of unknown function may be a circularly permuted homolog to phosphotriesterase, an enzyme capable of detoxifying organophosphate nerve agents. In a third example, the amino acid sequence of another hypothetical protein of unknown function reveals the ATP binding-site, metal binding site, and catalytic sidechain consistent with kinase activity of unknown specificity. This approach significantly expands the utility of existing sequence data to define the primary structure degeneracy of binding sites for substrates, cofactors and other proteins. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Chloroquine resistance in the malarial parasite, Plasmodium falciparum

MEDICINAL RESEARCH REVIEWS, Issue 5 2002
Lyann M.B. Ursos
Abstract Malarial parasites remain a health problem of staggering proportions. Worldwide, they infect about 500 million, incapacitate tens of millions, and kill approximately 2.5 million (mostly children) annually. Four species infect humans, but most deaths are caused by one particular species, Plasmodium falciparum. The rising number of malarial deaths is due in part to increased drug resistance in P. falciparum. There are many varieties of antimalarial drug resistance, and there may very well be several molecular level contributions to each variety. This is because there are a number of different drugs with different mechanisms of action in use, and more than one molecular event may sometimes be relevant for resistance to any one class of drugs. Thus, "multidrug" resistance in a clinical setting likely entails complex combinations of overlapping resistance pathways, each specific for one class of drug, that then add together to confer the particular multidrug resistance phenotype. Nonetheless, rapid progress has been made in recent years in elucidating mechanisms of resistance to specific classes of antimalarial drugs. As one example, resistance to the antimalarial drug chloroquine, which has been the mainstay therapy for decades, is becoming well understood. This article focuses on recent advances in determining the molecular mechanism of chloroquine resistance, with particular attention to the biochemistry and biophysics of the P. falciparum digestive vacuole, wherein changes in pH have recently been found to be associated with chloroquine resistance. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 5, 465,491, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10016 [source]


THE SON MORE VISIBLE: IMMATERIALISM AND THE INCARNATION

MODERN THEOLOGY, Issue 1 2010
MARC A. HIGHT
In this article we argue that an immaterialist ontology,a metaphysic that denies the existence of material substance,is more consonant with Christian dogma than any ontology that includes the existence of material substance. We use the philosophy of the famous eighteenth-century Irish immaterialist George Berkeley as a guide while engaging one particularly difficult Christian mystery: the doctrine of the Incarnation of Christ. The goal is to make plausible the claim that, from the analysis of this one example, there are strong reasons for thinking that if one wants to be a Christian one ought to be an immaterialist. [source]


High-performance liquid chromatographic separation of natural and synthetic desulphoglucosinolates and their chemical validation by UV, NMR and chemical ionisation-MS methods

PHYTOCHEMICAL ANALYSIS, Issue 4 2001
Guy Kiddle
Abstract Methods are described for the optimised extraction, desulphation and HPLC separation of desulphoglucosinolates. These methods provide rapid separation, identification and quantitative measurements of glucosinolates extracted from Brassica napus L and related crops, of unusual glucosinolates found in crucifer weed species, and also of synthetic alkylglucosinolates. The desulphoglucosinolates used in these studies were either chemically synthesised (at least one example from each major structural class), or purified from various plant sources. Validation of the identities of the desulphoglucosinolates was by comparison of retention times with standards, and by UV, 1H- and 13C-NMR and chemical ionisation MS analysis. A list of useful species, and the specific tissues, from which high concentrations of standards can be extracted is included. Copyright © 2001 John Wiley & Sons, Ltd. [source]


Migrant women in male-dominated sectors of the labour market: a research agenda

POPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 1 2008
Parvati Raghuram
Abstract There is a growing literature on female labour migration, but much of this focuses on women who move to work in labour-market sectors where a large proportion of workers are women. This paper argues that there has been much less study of women who migrate to work in male-dominated sectors of the labour market, and explores the nature of this lacuna within research on female migration. It then highlights the increasing presence of women migrants in the ICT sector as one example of an area that has received little study. Finally, the paper explores some reasons why a study of female migrant's experiences in male-dominated sectors of the labour market is important, and what it can add to existing research on female migration more generally. In particular, it urges us to view gender as it intersects and overlaps with other social divisions to produce complex landscapes of female mobility. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Seeking red herrings in the wood: tending the shared spaces of environmental and feminist geographies

THE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 1 2007
MAUREEN G. REED
In this article I argue the need for feminist and environmental geographers to work more diligently to find, mind and tend the intersections of their research agendas to enrich scholarship and deepen impacts on public policy. Such a project requires us to move beyond an obvious call to acknowledge one another's work and towards the boundaries of our respective fields in order to co-create ,boundary objects' that provide opportunities for mutual exchange, collaboration and learning. Rather than being ,red herrings' or diversions from our main research foci, boundary objects bring new insights to taken-for-granted concepts. I focus on one example to argue that social sustainability of rural places is better understood by an integrated understanding of what constitutes a ,worker' in a forestry community. A redefinition of the worker that draws on insights and interests from both environmental and feminist geographers reveals an underlying gender bias in environmental decision-making processes and illustrates how the concept of social sustainability has been artificially restricted in practice. Nevertheless, collaborations are never easy. I draw attention to potential challenges of such collaborations that include the need to establish mutually agreeable protocols, joint commitment to constructive, respectful debate and strategies to ensure that research provides meaningful contributions to theory and public policy. Dans cet article, je vais tenter de montrer que les géographes féministes et les géographes de l'environnement auront à travailler avec plus d'acharnement pour reconnaître, étudier et entretenir les points communs de leurs agendas de recherche en vue d'augmenter la valeur scientifique des études et d'accroître les retombées sur les politiques publiques. Un tel projet exige que nous puissions dépasser le stade de la reconnaissance de nos travaux et se tourner ainsi vers les frontières de nos disciplines afin de co-créer des ,objets frontaliers' qui offrent des possibilités d'échanges d'idées, de collaboration et d'apprentissage. Plutôt qu'être des ,fausses pistes' ou des déviations de nos principaux thèmes de recherche, ces objets frontaliers pourraient apporter un éclairage nouveau sur des concepts tenus pour acquis. À l'aide d'un exemple, j'avance que pour mieux comprendre la durabilité sociale en milieux ruraux, il faut acquérir une compréhension intégrée de l'ensemble des dimensions d'un ,ouvrier' membre d'une communauté forestière. L'ouvrier est redéfini en mettant à contribution les connaissances et intérêts des géographes environnementaux et féministes. Cette définition met au jour un parti pris fondé sur le sexe dans les processus décisionnels en matière d'environnement et démontre de quelle façon le concept de la durabilité sociale s'en trouve artificiellement restreint dans la pratique. Les collaborations ne sont cependant jamais faciles àétablir. J'attire l'attention sur les difficultés potentielles de ces collaborations concernant notamment la mise en place de protocoles acceptables pour les deux parties, la promesse de tenir des débats constructifs et respectueux, et les stratégies visant à garantir que la recherche participe de manière vitale autant au développement de la théorie que des politiques publiques. [source]


Treasonous Conduct: Assessing the Wartime Activities, Post-War Trials and Tribulations of Australian Collaborators in the Second World War,

AUSTRALIAN JOURNAL OF POLITICS AND HISTORY, Issue 1 2009
Robert Loeffel
There has been very little written about the activities of Australian citizens collaborating with the Germans during the Second World War. There are, however, a few instances where Australian citizens were involved in activities in Germany which could be considered treasonous. A number of these were individuals involved in an ill-conceived military unit created by the Germans from British prisoners of war while there is at least one example of an Australian who allegedly carried out propaganda broadcasts for the Germans. The activities of these individuals and the way the authorities dealt with these cases after the war will be the focus of this article. [source]


Fold evolution and drainage development in the Zagros mountains of Fars province, SE Iran

BASIN RESEARCH, Issue 1 2008
Lucy A. Ramsey
ABSTRACT A central question in structural geology is whether, and by what mechanism, active faults (and the folds often associated with them) grow in length as they accumulate displacement. An obstacle in our understanding of these processes is the lack of examples in which the lateral growth of active structures can be demonstrated definitively, as geomorphic indicators of lateral propagation are often difficult, or even impossible to distinguish from the effects of varying lithology or non-uniform displacement and slip histories. In this paper we examine, using the Zagros mountains of southern Iran as our example, the extent to which qualitative analysis of satellite imagery and digital topography can yield insight into the growth, lateral propagation, and interaction of individual fold segments in regions of active continental shortening. The Zagros fold-and-thrust belt contains spectacular whaleback anticlines that are well exposed in resistant Tertiary and Mesozoic limestone, are often >100 km in length, and which contain a large proportion of the global hydrocarbon reserves. In one example, Kuh-e Handun, where an anticline is mantled by soft Miocene sediments, direct evidence of lateral fold propagation is recorded in remnants of consequent drainage patterns on the fold flanks that do not correspond to the present-day topography. We suggest that in most other cases, the soft Miocene and Pliocene sediments that originally mantled the folds, and which would have recorded early stages in the growth histories, have been completely stripped away, thus removing any direct geomorphic evidence of lateral propagation. However, many of the long fold chains of the Zagros do appear to be formed from numerous segments that have coalesced. If our interpretations are correct, the merger of individual fold segments that have grown in length is a major control on the development of through-going drainage and sedimentation patterns in the Zagros, and may be an important process in other regions of crustal shortening as well. Abundant earthquakes in the Zagros show that large seismogenic thrust faults must be present at depth, but these faults rarely reach the Earth's surface, and their relationship to the surface folding is not well constrained. The individual fold segments that we identify are typically 20,40 km in length, which correlates well with the maximum length of the seismogenic basement faults suggested from the largest observed thrusting earthquakes. This correlation between the lengths of individual fold segments and the lengths of seismogenic faults at depth suggest that it is possible, at least in some cases, that there may be a direct relationship between folding and faulting in the Zagros, with individual fold segments underlain by discrete thrusts. [source]


When is profiling possible?

BEHAVIORAL SCIENCES & THE LAW, Issue 6 2007
Offense planning, aggression as moderators in predicting offender age from victim age in stranger rape
Debate continues with regard to the possibility of inferring an offender's characteristic features from crime scene details (the process of so-called "offender profiling"). We argue that psychology generally has benefited from appreciating context in predicting behavior. In the same way, profiling would benefit from an appreciation of context in predicting characteristics. This "reverse" process is contingent on various "if,then" relationships. As one example, this paper demonstrates how profiling offender age from victim age is contingent on (i) the level of planning and (ii) the level of aggression displayed during the offense. Eighty-five stranger rape case records formed the data set. Moderated regression analysis revealed that victim age is a significant predictor of offender age only in cases where the offender has (i) shown evidence of planning the attack and/or (ii) acts in a gratuitously aggressive manner. The theoretical bases for these findings may lie in the extent to which offenders disparately plan and target victims and how extreme aggressiveness in stranger rapes may relate to a near-peer proxy for an offender's anger. The implications of the results for the processes and methods involved in offender profiling suggest that certain crime scene factors can have differential moderating effects on predictive outcomes. Copyright © 2007 John Wiley & Sons, Ltd. [source]


No effect of extremely low-frequency magnetic field observed on cell growth or initial response of cell proliferation in human cancer cell lines

BIOELECTROMAGNETICS, Issue 5 2002
Hiroaki Yoshizawa
Abstract An effect on the tumor promotion process, as represented by accelerated cell growth, has been indicated as one example of areas that demonstrate the possibility of biological effects of extremely-low frequency magnetic fields. We, therefore, exposed the five cell lines (HL-60, K-562, MCF-7, A-375, and H4) derived from human tumors to a magnetic field for 3 days to investigate the effects on cell growth. Prior to exposure or sham exposure, the cells were precultured for 2 days in low serum conditions. The number of growing cells was counted in a blind manner. To investigate the effect on the initial response of cell proliferation, two cell lines were synchronized in G1 phase by serum starvation and then exposed to a magnetic field for 18 h (H4 cells) or 24 h (MCF-7 cells), both with and without serum stimulation. The rate of DNA synthesis, taken as a measure of the cell proliferation, was determined by following the incorporation of [3H]-thymidine into the DNA. Three different magnetic field polarizations at both 50 and 60 Hz were used: linearly polarized (vertical); circularly polarized; and an elliptically polarized field. Magnetic field flux densities were set at 500, 100, 20 and 2 ,T (rms) for the vertical field and at 500 ,T (rms) for the rotating fields. No effect of magnetic field exposure was observed on either cell growth or the initial response of cell proliferation. Bioelectromagnetics 23:355,368, 2002. © 2002 Wiley-Liss, Inc. [source]


Regional Cultural Differences and Ethical Perspectives within the United States: Avoiding Pseudo-emic Ethics Research

BUSINESS AND SOCIETY REVIEW, Issue 1 2010
BRENT MACNAB
ABSTRACT National cultures are often described as if they were homogeneous in spite of notable regional differences. As one example, there are significant differences between two distinct regions of the United States, Hawaii and Florida. This study provides a platform to exemplify a more regionally aware position for cultural and ethics research. Using select Hofstede cultural dimensions, regional differences were found in relation to both collectivism/individualism and uncertainty avoidance. The Hawaii sample had higher levels of collectivism and uncertainty avoidance, demonstrating unique regional-cultural patterns within the United States. Regional samples were examined for potential differences in their general perception of what constitutes ethical business practice. While honesty appeared as a key trait across samples, significant differences emerged in the magnitude of importance between samples for integrity (which was more significant for the Hawaii sample) and loyalty (which was more significant for the Florida sample). [source]


Cobalt-Mediated Linear 2:1 Co-oligomerization of Alkynes with Enol Ethers to Give 1-Alkoxy-1,3,5-Trienes: A Missing Mode of Reactivity

CHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2010
David Leb, uf Dr.
Abstract A variety of 1,6-heptadiynes and certain borylalkynes co-oligomerize with enol ethers in the presence of [CpCo(C2H4)2] (Cp=cyclopentadienyl) to furnish the hitherto elusive acyclic 2:1 products, 1,3,5-trien-1-ol ethers, in preference to or in competition with the alternative pathway that leads to the standard [2+2+2] cycloadducts, 5-alkoxy-1,3-cyclohexadienes. Minor variations, such as lengthening the diyne tether, cause reversion to the standard mechanism. The trienes, including synthetically potent borylated derivatives, are generated with excellent levels of chemo-, regio-, and diastereoselectivity, and are obtained directly by decomplexation of the crude mixtures during chromatography. The cyclohexadienes are isolated as the corresponding dehydroalkoxylated arenes. In one example, even ethene functions as a linear cotrimerization partner. The alkoxytrienes are thermally labile with respect to 6,-electrocyclization,elimination to give the same arenes that are the products of cycloaddition. The latter, regardless of the mechanism of their formation, can be viewed as the result of a formal [2+2+2] cyclization of the starting alkynes with acetylene. One-pot conditions for the exclusive formation of arenes are developed. DFT computations indicate that cyclohexadiene and triene formation share a common intermediate, a cobaltacycloheptadiene, from which reductive elimination and ,-hydride elimination compete. [source]


Molecules with New Topologies Derived from Hydrogen-Bonded Dimers of Tetraurea Calix[4]arenes

CHEMISTRY - A EUROPEAN JOURNAL, Issue 28 2008
Anca Bogdan Dr.
Abstract Tetraurea calix[4]arenes 2 have been synthesized in which two adjacent aryl urea residues are connected to a loop by an aliphatic chain -O-(CH2)n -O-. The remaining urea residues have a bulky 3,5-di- tert -butylphenyl residue and an , -alkenyloxyphenyl residue. Since this bulky residue cannot pass through the loop, only one homodimer (2,2) is formed in apolar solvents, for steric reasons, in which the two alkenyl residues penetrate the two macrocyclic loops. Covalent connection of these alkenyl groups by olefin metathesis followed by hydrogenation creates compounds 3, which consist of molecules with hitherto unknown topology. Their molecular structure was confirmed by 1H,NMR spectroscopy and ESIMS, and for one example by single-crystal X-ray analysis. [source]


Uniform Metal (Hydr)Oxide Particles from Water/Ionic Liquid Precursor (ILP) Mixtures

CHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2008
Zhonghao Li Dr.
Abstract We have recently shown that the hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of ZnO/carbohydrate materials (D. Mumalo-Djokic, W.,B. Stern, A. Taubert, Cryst. Growth Des.2008, 8, 330). The current paper shows that ZnO is just one example out of the large group of technologically important metal (hydr)oxides that can be made using TBAH. Simply by using different metal acetates as precursors in TBAH, it is possible to make a wide variety of metal (hydr)oxides with well-defined size, morphology, and chemical composition. It is also possible to dope metal oxide particles or to synthesize mixed metal oxide particles, and therefore to control properties like magnetism. [source]


Calix[4]arene-Based Bis[2]catenanes: Synthesis and Chiral Resolution

CHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007
Olena Molokanova
Abstract The exclusive formation of hydrogen-bonded dimers between tetraaryl and tetratosylurea calix[4]arenes has been used to prepare a series of ten "bisloop" tetraurea calix[4]arenes 3, in which adjacent phenylurea groups are covalently linked through ,,,-dioxyalkane chains. This dimerization with tetratosylurea 2 as template preorganizes the alkenyl residues of tetra(m -alkenyloxyphenyl) ureas 1 and enables their selective connection in high yield (up to 95,%) by olefin metathesis followed by hydrogenation. The "bisloop" calixarenes 3 also exclusively form heterodimers with 1. Thus, in a separated metathesis/hydrogenation sequence, a series of 14 cyclic bis[2]catenanes 4, in which two calix[4]arenes are connected through their wide rims by two pairs of interlocked rings (total size 29 to 41 atoms), were prepared in yields of up to 97,%. Optical resolution of these chiral bis[2]catenanes was studied by HPLC on chiral stationary phases. The single-crystal X-ray structure of one example (4(P,10)) confirmed the interlocking rings and revealed that the hydrogen-bonded dimeric capsule of the calix[4]arene can be "completely" opened. [source]


Germanates of 1D Chains, 2D Layers, and 3D Frameworks Built from Ge,O Clusters by Using Metal-Complex Templates: Host,Guest Symmetry and Chirality Transfer

CHEMISTRY - AN ASIAN JOURNAL, Issue 10 2007
Guang-Zhen Liu
Abstract The self-assembly of Ge,O polyhedra by metal-complex templates leads to initial examples of open germanate structures under mild solvothermal conditions. These materials are constructed from Ge,O cluster building bocks (Ge7X19 (X=O, OH, or F) or Ni@Ge14O24(OH)3) and span the full range of dimensionalities from 1D chains of Ge7O13(OH)2F3,Cl,2[Ni(dien)2] (FJ- 6) to 2D layers of Ge7O14F3,0.5[In(dien)2],0.5H3dien, 2H2O (1) and 3D frameworks of Ni@ Ge14O24(OH)3,2[Ni(L)3] (FJ- 1,a/FJ- 1,b) (dien=diethylenetriamine, L=ethylenediamine (en) or 1,2-diaminopropane (enMe)). The Ge7X19 cluster in FJ- 6 and 1 is formed by condensation of four GeX4 tetrahedra, two GeX5 trigonal bipyramids, and one GeX6 octahedron with a ,3 -O atom at the center of the cluster, whereas the Ni@ Ge14O24(OH)3 cluster in FJ- 1,a/FJ- 1,b is formed by condensation of nine peripheral GeO4 tetrahedra and five interior GeO3Ni units with one ,5 -Ni atom at the center of the cluster. FJ- 6 is characterized by a pair of racemic Ge7O14(OH)2F3 cluster chains and represents only one example of 1D germanates; 1 exhibits unique germanate layers with uniform 10-membered-ring apertures encapsulating an unknown indium complex, and the framework structure of FJ- 1,a/FJ- 1,b with large 24-membered-ring channels is the first example of porous materials that contain metal,metal bonds (Ge2+Ni+). These initial examples of germanates from metal-complex templates provide a useful model system for understanding the mechanisms of host,guest interactions, which may further facilitate the design and development of new porous materials "on demand". It is shown that the symmetry and configuration of the guest metal complex can be imprinted onto the host inorganic framework through hydrogen bonding between host and guest. [source]