bluuebunny/crossref_metadata_2025 huggingface dataset:
Ag and Au nanoparticles for SERS substrates produced by pulsed laser ablation
Authors: Agarwal N. R. , Fazio E. , Neri F. , Trusso S. , Castiglioni C. , Lucotti A. , Santo N. , Ossi P. M.
Published: May 2011

A method for the growth of films consisting of Nanoparticles (NP) of Ag and Au is presented. Nanostructured films were obtained by means of nanosecond pulsed laser ablation of a metallic target in presence of a controlled Ar atmosphere. The morphology of these films from island structures to isolated nanoparticles, measured by SEM, depends on the varying gas pressure (10‐100 Pa) and on the number of laser pulses (500‐30000), keeping other deposition parameters such as the target to substrate distance, incidence angle, laser wavelength, laser fluence constant. Fast imaging of the plasma, performed using a intensified and gateable CCD camera at different time delays with respect to the arrival of the laser pulse, allows revelation of the propagation regime of the ablation plume and inference of plasma initial velocity. This data along with the measured average ablated mass per pulse were taken as inputs to a model to estimate the average size of NPs grown in the expanding plume. The theoretical NP sizes were compared with sizes measured from TEM images. These images indicate narrow gradients of NP sizes. Hence strict control of growth parameters aids fine tuning of NP size that is essential for many applications, including Surface Enhanced Raman Spectroscopy (SERS) active substrates. UV‐Visible Spectroscopy helped in determination of appropriate laser wavelength for resonant excitation of the localized surface plasmon. SERS Spectra obtained with increasingly lower concentrations of reference dye Rhodamin 6G (Rh6G) and medical drug Apomorphine, are discussed as a perspective of application to biomedical sensors. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Morphology of gypsum: a case study
Authors: Rubbo M. , Massaro F. R. , Aquilano D. , Vanzetti W.
Published: May 2011

In this paper we present an approach to the determination of the equilibrium and growth morphologies of the gypsum (CaSO4.2H2O). This is based on the generation of crystal surface using different methods in such a way to span a great number of initially unrelaxed surface configurations. The resulting equilibrium and growth morphologies are compared with the morphology of minerals from Naica, whose genetic conditions are fairly well known. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spectroscopic study of β‐SiC prepared via PLD at 1064 nm
Authors: Monaco G. , Garoli D. , Natali M. , Romanato F. , Nicolosi P.
Published: May 2011

The physical properties of the wide band‐gap β‐SiC make it a promising material for future applications in high‐power, high‐temperature and high‐frequency devices. Up to now, SiC has been successfully employed in field effect transistors, bipolar storage capacitors and ultraviolet detectors. In this work, we present new attempts to prepare crystalline β‐SiC at 650 °C by means of Pulsed Laser Deposition (PLD). X‐Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) have been used to determine the crystalline and morphological properties of the deposited β‐SiC thin films grown on different substrates: sapphire and silicon. The optical constants in the visible range and the band gap energy have been determined by Spectroscopic Ellipsometry (SE) which is a powerful non‐destructive technique for high accuracy measurements. SiC thin films deposited on sapphire give rise to hetero‐epitaxial growth resulting in an organized structure while the sample deposited on silicon grows polycrystalline. The correlation between the band‐gap energy and the crystalline phases and growth conditions will be discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of precursor concentration on structural, morphological and electrical properties of spray deposited ZnO thin films
Authors: Sivalingam D. , Gopalakrishnan J. B. , Balaguru Rayappan J. B.
Published: May 2011

Nanostructured ZnO thin films were coated on glass substrate by spray pyrolysis using Zinc acetate dihydrate as precursor. Effect of precursor concentration on structural, morphological, optical and electrical properties of the films was investigated. The crystal structure and orientation of the ZnO thin films prepared with four different precursor solution concentrations were studied and it was observed that, the prepared films are polycrystalline in nature with hexagonal wurzite structure. The peaks are indexed to (100), (002), (101), (102) and (110) planes. Grain size and texture coefficient (TC) were calculated and the grain size found to increase with an increase in precursor concentration. Presence of Zn and O elements was confirmed with EDAX spectra. Optical absorption measurements were carried out in the wavelength region of 380 to 800 nm and the band gap decreases as precursor concentration increases. The current‐voltage characteristics were observed at room temperature and in dark. It was found that for the films deposited at four different precursor concentrations, the conductivity improves as precursor concentration increases. As trimethyl amine TMA is a good marker for food quality discrimination, sensing behavior of the films at an optimized operating temperature of 373 K, towards various concentrations of (TMA) was observed and reported. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of vertically‐aligned GaAs nanowires on GaAs/(111)Si hetero‐substrates by metalorganic vapour phase epitaxy
Authors: Miccoli I. , Prete P. , Marzo F. , Cannoletta D. , Lovergine N.
Published: May 2011

We report on the Au‐catalysed synthesis of GaAs nanowires on hetero‐structured GaAs/(111)Si substrates by metalorganic vapour phase epitaxy. It is demonstrated that the deposition of a 40‐50 nm thin GaAs epilayer onto Si guarantees a high percentage of straight and vertically‐aligned GaAs nanowires. GaAs epilayers were grown at 400 °C and subsequently annealed at 700 °C. Growth experiments performed on 4°‐miscut and exactly‐oriented (111)Si substrates show that a higher yield (close to 90%) of vertical nanowires is obtained using miscut substrates, an effect ascribed to the smoother surface morphology of GaAs epilayers on these substrates. Comparison between the cross‐sectional shape of nanowires grown on GaAs/(111)Si hetero‐substrates and those on (111)A‐GaAs and (111)B‐GaAs substrates demonstrates that both GaAs epilayers and over‐grown nanowires are (111)B‐oriented. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of ZnO buffer layer on structural and optical properties of ZnO nanorods
Authors: Lang Jihui , Li Xue , Yang Jinghai , Han Qiang , Yan Yongsheng , Gao Ming , Wang Dan , Yang Lili , Liu Xiaoyan , Wang Rui , Yang Suyang
Published: May 2011

A low‐temperature synthetic route was used to prepare oriented arrays of ZnO nanorods on ITO conducting glass substrate coated with buffer layer of ZnO seeds in an aqueous solution. The corresponding growth behavior and optical properties of ZnO nanorod arrays were studied. It was found that the nature of the buffer layer had effect on the microstructures and optical properties of the resultant ZnO nanorod arrays. X‐ray diffraction (XRD) results showed the nanorods were preferentially grown along (002) direction, but the diameter of the nanorods prepared with the buffer layer was much smaller than the without one, which can be clearly seen from the scanning electron microscopy (SEM) results. And it also found that the buffer layer was not only enhanced the density of overall coverage but also beneficial to grown the oriented arrays. Photoluminescence spectroscopy (PL) results indicated that the all the samples had the better optical behaviors. By computation, the relative PL intensity ratio of ultraviolet emission (IUV) to deep level emission (IDLE) of ZnO nanorods grown with the pure substrate was much higher than that of the sample with the buffer layer. The defects on the surface increased with the size reduction of nanorods caused by the buffer layer may be the main reason for it. And the small shift in the UV emission was caused by the rapid reduction in crystal size and compressive stress from Raman spectra results. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Xenopus laevis insulin receptor substrate IRS‐1 is important for eye development
Authors: Bugner Verena , Aurhammer Thomas , Kühl Michael
Published: May 2011

Extracellular signal transduction into cells through ligand‐activated receptor tyrosine kinases, such as insulin‐like growth factor‐1 (IGF‐1) receptor (IGF‐1R) and insulin receptor (IR) is required for normal embryonic growth and development. The major mediators of IR and IGF‐1R are adaptor proteins of the insulin receptor substrate family, the best characterized member of which is IRS‐1. Insulin receptor substrate IRS‐1 has been shown to influence cell and body size and to interfere with differentiation. We have isolated IRS‐1 from Xenopus laevis embryos and analyzed for the first time its spatial and temporal expression pattern during embryogenesis. We found that Xenopus IRS‐1 is expressed maternally and constantly during embryogenesis. It is predominantly found in neural tissue at different stages. Furthermore, knock down of IRS‐1 in neural tissue by specific antisense morpholino oligonucleotides (MO) resulted in abnormal eye formation accompanied by reduction of the eye‐specific marker genes Rx1 and Pax6 and a decreased cell proliferation. Developmental Dynamics 240:1705–1715, 2011. © 2011 Wiley‐Liss, Inc.
Mucocutaneous candidiasis and autoimmunity against cytokines in APECED and thymoma patients: Clinical and pathogenetic implications
Authors: Kisand Kai , Lilic Desa , Casanova Jean‐Laurent , Peterson Pärt , Meager Anthony , Willcox Nick
Published: May 2011

Much has been learnt about the mechanisms of thymic self‐tolerance induction from work on both the rare autosomal recessive disease autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) and the autoimmune regulator (AIRE) protein mutated in this disease. Normally, AIRE drives low‐level expression of huge numbers of peripheral tissue‐specific antigens (TSAgs) in medullary thymic epithelial cells (mTECs), leading to the deletion of TSAg‐reactive thymocytes maturing nearby. The very recently discovered neutralizing autoantibodies (autoAbs) against Th17‐related cells and cytokines in two autoimmunity‐related syndromes associated with AIRE‐mutant thymi or AIRE‐deficient thymomas help to explain the chronic mucocutaneous candidiasis (CMC) seen in both syndromes. The surprising parallels between these syndromes also demand new hypotheses and research into the consequences of AIRE deficiency and the ensuing autoimmunizing pathways, and suggest more appropriate treatment regimens as discussed in this review.
Electron and Spin Density Topology of the H‐Cluster and Its Biomimetic Complexes
Authors: Giles Logan J. , Grigoropoulos Alexios , Szilagyi Robert K.
Published: May 2011

The catalytically active cluster of [FeFe]‐hydrogenase (H‐cluster) is unique due to its chemical composition and electronic and geometric structures. Protein crystallography revealed the presence of biologically unique diatomic ligands coordinating to the Fe centers and three light atoms bridging the sulfur atoms of its [2Fe]‐subcluster. The identity of the light atoms remains uncertain, even at close to atomic resolution (1.39 Å), as well as due to the lack of understanding at the molecular level of the cluster's biosynthetic pathway. By using all of the proposed ligand compositions, we carried out a comprehensive electronic structure analysis by evaluating the topology of the electron density and, particularly, the atomic spin density distribution derived from various population analysis methods for the free dithiolate ligands, the biomimetic [2Fe] complexes, and the entire H‐cluster embedded in its approximately 3.5 Å protein environment. In the biomimetic model complexes we found substantial spin density delocalization at the bridgehead of the dithiolate ligands. We attributed the presence of spin density to the through‐space spin polarization interaction between the paramagnetic iron centers and the bridgehead group, as represented by the ring critical points for the [Fe–(S–R–S)–Fe] metallacycles. However, this spin polarization of the bridgehead group vanishes for some of the biomimetic models, as well as for the 208‐atom computational model of the H‐cluster, due to a network of weak interactions. When the bridgehead group becomes part of a conduit for transmitting the spin polarization towards the terminal ends of each interaction network, such as the distal water or H‐bonded residues, the spin density vanishes. The variations of the Fe atomic spin densities were compared and contrasted for the proximal and distal iron sites in the crystallographic and the rotated conformations, respectively.
Dynamic viscosity of olive oil as a function of composition and temperature: A first approach
Authors: Bonnet Jean‐Philippe , Devesvre Laurie , Artaud Jacques , Moulin Philippe
Published: May 2011

Knowledge of the viscosity of virgin olive oils (VOOs) is of great importance for the design of pilot plants, to determine the time required for the settling of particles at the end of the production chain and from a sensory view point. The dynamic viscosities of French VOOs from four different cultivars (‘Aglandau’, ‘Bouteillan’, ‘Salonenque’ and ‘Tanche’) were studied as a function of their fatty acid and TAG compositions and of the temperature [10–50°C]. These four VOOs had different TAG and fatty acid compositions representative of the range of compositional variations in the main French oils. Their viscosities were similar, although small but measurable differences that depended on their compositions were apparent. All the VOO samples exhibited the same dynamic viscosity pattern over temperature. For a given temperature, the viscosity difference was the greatest between Aglandau and Salonenque oils, Aglandau being the oil with the highest viscosity. The correlation between temperature and viscosity was highlighted by an Arrhenius model for this Newtonian fluid. The Arrhenius activation energy was correlated (R2 = 0.993) with the percentage of triolein, the main TAG in olive oil.
Strategies Based on Aryllithium and N‐Acyliminium Ion Cyclizations for the Stereocontrolled Synthesis of Alkaloids and Related Systems
Authors: Martínez‐Estibalez Unai , Gómez‐SanJuan Asier , García‐Calvo Oihane , Aranzamendi Eider , Lete Esther , Sotomayor Nuria
Published: May 2011

The intramolecular α‐amidoalkylation reactions of aromatic and heteroaromatic ring systems constitute a versatile approach for the synthesis of nitrogen heterocyles in a diastereoselective or enantioselective fashion. On the other hand, the intramolecular reactions of aryllithium compounds have also been extensively used in the synthesis of carbocycles and heterocycles. The use of imides as internal electrophiles is particularly attractive because of the potential to introduce diverse functionality into the cyclized products by subjecting the resulting α‐hydroxylactams to intermolecular reactions with nucleophiles through intermediate N‐acyliminium cations. This metalation/cyclization/α‐amidoalkylation sequence can be diastereocomplementary with intramolecular α‐amidoalkylation reactions via N‐acyliminium ions derived from the corresponding imides. This review focuses on recent developments of synthetic methods for heterocyclic systems (alkaloids and related systems) based on aryllithium compouns and N‐acyliminium ion cyclizations, with special attention to the stereocontrolled formation of carbon–carbon bonds.
C–H Bond Functionalization of Arylpyrimidines Catalyzed by an in situ Generated Ruthenium(II) Carboxylate System and the Construction of Tris(heteroaryl)‐Substituted Benzenes
Authors: Štefane Bogdan , Fabris Jan , Požgan Franc
Published: May 2011

A ruthenium(II) carboxylate catalyst, generated in situ from [RuCl2(p‐cymene)]2 and 1‐phenyl‐1‐cyclopentanecarboxylic acid (PCCA) in the presence of K2CO3, allowed activation of the C–H bond in phenyl‐substituted pyrimidines and their direct functionalization with both electron‐deficient and electron‐rich aryl halides. The scope of this process can be extended to the use of heteroaryl bromides and less reactive aryl chlorides. This RuII‐PCCA complex constitutes a better catalytic system in comparison to other carboxylates.
Effects of near‐fault ground motions on the nonlinear dynamic response of base‐isolated r.c. framed buildings
Authors: Mazza Fabio , Vulcano Alfonso
Published: May 2011

Near‐fault ground motions are characterized by long‐period horizontal pulses and high values of the ratio between the peak value of the vertical acceleration, PGAV, and the analogous value of the horizontal acceleration, PGAH, which can become critical for base‐isolated (BI) structures. The objective of the present work is to check the effectiveness of the base isolation of framed buildings when using High‐Damping‐Rubber Bearings (HDRBs), taking into consideration the combined effects of the horizontal and vertical components of near‐fault ground motions. To this end, a numerical investigation is carried out with reference to BI reinforced concrete buildings designed according to the European seismic code (Eurocode 8). The design of the test structures is carried out in a high‐risk region considering (besides the gravity loads) the horizontal seismic loads acting alone or in combination with the vertical ones and assuming different values of the ratio between the vertical and horizontal stiffnesses of the HDRBs. The nonlinear seismic analysis is performed using a step‐by‐step procedure based on a two‐parameter implicit integration scheme and an initial‐stress‐like iterative procedure. At each step of the analysis, plastic conditions are checked at the potential critical sections of the girders (i.e. end sections of the sub‐elements in which a girder is discretized) and columns (i.e. end sections), where a bilinear moment–curvature law is adopted; the effect of the axial load on the ultimate bending moment (M‐N interaction) of the columns is also taken into account. The response of an HDRB is simulated by a model with variable stiffness properties in the horizontal and vertical directions, depending on the axial force and lateral deformation, and linear viscous damping. Copyright © 2011 John Wiley & Sons, Ltd.
Short‐term versus medium‐term monitoring for detecting gully‐erosion variability in a Mediterranean environment
Authors: Marzolff Irene , Ries Johannes B. , Poesen Jean
Published: May 2011

This study investigates how medium‐term gully‐development data differ from short‐term data, and which factors influence their spatial and temporal variability at nine selected actively retreating bank gullies situated in four Spanish basin landscapes. Small‐format aerial photographs using unmanned, remote‐controlled platforms were taken at the gully sites in short‐term intervals of one to two years over medium‐term periods of seven to 13 years and gully change during each period was determined using stereophotogrammetry and a geographic information system. Results show a high variability of annual gully retreat rates both between gullies and between observation periods. The mean linear headcut retreat rates range between 0·02 and 0·26 m a–1. Gully area loss was between 0·8 and 22 m² a–1 and gully volume loss between 0·5 to 100 m³ a–1, of which sidewall erosion may play a considerable part. A non‐linear relationship between catchment area and medium‐term gully headcut volume change was found for these gullies. The short‐term changes observed at the individual gullies show very high variability: on average, the maximum headcut volume change observed in 7–13 years was 14·3 times larger than the minimum change. Dependency on precipitation varies but is clearly higher for headcuts than sidewalls, especially in smaller and less disturbed catchments. The varying influences of land use and human activities with their positive or negative effects on runoff production and connectivity play a dominant role in these study areas, both for short‐term variability and medium‐term difference in gully development. The study proves the value of capturing spatially continuous, high‐resolution three‐dimensional data using small‐format aerial photography for detailed gully monitoring. Results confirm that short‐term data are not representative of longer‐term gully development and demonstrate the necessity for medium‐ to long‐term monitoring. However, short‐term data are still required to understand the processes – particularly human activity at varying time scales – causing fluctuations in gully erosion rates. Copyright © 2011 John Wiley & Sons, Ltd.
Carbon fluxes from eroding peatlands – the carbon benefit of revegetation following wildfire
Authors: Worrall F. , Rowson J. G. , Evans M. G. , Pawson R. , Daniels S. , Bonn A.
Published: May 2011

Peatlands are among the largest long‐term soil carbon stores, but their degradation can lead to significant carbon losses. This study considers the carbon budget of peat‐covered sites after restoration, following degradation by past wildfires. The study measured the carbon budget of eight sites: four restored‐revegetated sites, two unrestored bare soil control sites, and two intact vegetated controls over two years (2006–2008). The study considered the following flux pathways: dissolved organic carbon (DOC); particulate organic carbon (POC); dissolved carbon dioxide (CO2); primary productivity; net ecosystem respiration, and methane (CH4). The study shows that unrestored, bare peat sites can have significant carbon losses as high as 522 ± 3 tonnes C/km2/yr. Most sites showed improved carbon budgets (decreased source and/or increased sink of carbon) after restoration; this improvement was mainly in the form of a reduction in the size of the net carbon source, but for one restored site the measured carbon budget after four years of restoration was greater than observed for vegetated controls. The carbon sequestration benefit of peatland restoration would range between 122 and 833 tonnes C/km2/yr. Copyright © 2011 John Wiley & Sons, Ltd.
Effect of ion‐slip current on the thermal instability of mixed connection in a boundary layer flow
Authors: Lin Ming‐Han
Published: May 2011

Effect of ion‐slip current on the thermal instability in a boundary layer is studied. The criterion on the position marking the onset of longitudinal vortices is defined in the present paper. The results show that the onset position characterized by the Grashof number depends on the Prandtl number, the Reynolds number, the wave number, the Hall parameter, the ion‐slip parameter, and the Hartmann number. The flow becomes more stable as the magnetic field increases. However, the destabilizing effects are found on the flow when the Hall and ion‐slip currents are presented. The results of the present numerical prediction show reasonable agreement with the experimental data in the case of zero Hartmann number, ion‐slip parameter, and Hall parameter in the open literature. Copyright © 2011 John Wiley & Sons, Ltd.
Character and origin of variably deformed granitoids in central southern Sweden: implications from geochemistry and Nd isotopes
Authors: Appelquist Karin , Brander Linus , Johansson Åke , Andersson Ulf Bertil , Cornell David
Published: May 2011

We present major and trace element data for eighteen 1.71–1.66 Ga granitoid samples, and Sm–Nd whole‐rock isotope data for eleven of these samples, in a transect across the border between the Transscandinavian Igneous Belt (TIB) and the Eastern Segment in central southern Sweden. The geochemistry of the granitoids varies from alkalic to alkali‐calcic and peraluminous in the east to predominantly calc‐alkaline and metaluminous in the west. Rocks in the west also have lower SiO2contents. Trace element signatures favour formation in an active continental margin setting. Nd isotope data are completely overlapping along the transect and initialεNdvalues are mildly depleted in the range +0.3 to +2.6. The combined data suggest that the magmas were derived mainly from juvenile, pre‐existing crust, increasingly mafic and less alkaline towards the west. Copyright © 2011 John Wiley & Sons, Ltd.
How tight an embrace? Choosing the optimal degree of partner interaction in alliances based on risk, technology characteristics, and agreement provisions
Authors: Contractor Farok J. , Woodley James A. , Piepenbrink Anke
Published: May 2011

This study examines a key question one asks when negotiating an alliance: ‘how tight or loose a relationship do we wish to have with our partner?’ Interaction with one's partner is necessary in order to coordinate operations, effectively transfer tacit knowledge, monitor for opportunism, maximize joint synergistic value, and make sure that an appropriate share of the net benefit created by the alliance is appropriated by the technology provider. However, too tight an ‘embrace’ or too high a degree of interaction between the allies can increase coordination costs and increase the chance of unintended technology leakage. The sample, comprising 95 international alliances involving technology transfers, is grouped into four clusters with rising levels of interaction between allies. The optimal degree of interaction between the partners is explained by variables drawn from (1) technology characteristics and future technology policy, (2) coordination costs and risks, (3) agreement provisions, and (4) firm and sector characteristics that existed during the negotiation of the alliance. Using a proportional odds model, variables in the ‘coordination costs and risks’ and ‘agreement provisions’ categories found the most support in the results.
Form follows function? Interorganizational networks as a strategic imperative for global strategies
Authors: Parkhe Arvind
Published: May 2011

P&G's global networks are the platform for the activities that, together, constitute the connect‐and‐develop strategy. (Huston and Sakkab,2006: 62).

The main goal of any global strategy must be to manage the large differences that arise at borders, whether those borders are defined geographically or otherwise . . . Not all integration that is required to add value across borders needs to occur within a single organization. IBM and other firms illustrate that some externalization is a key part of most ambitious global strategies. (Ghemawat,2007: 67).
The strategic assembly of global firms: A microstructural analysis of local learning and global adaptation
Authors: Koza Mitchell P. , Tallman Stephen , Ataay Aylin
Published: May 2011

Strategic assembly—the comprehensive and coordinated use of internal development, mergers, acquisitions, joint ventures, and alliances—is a novel approach to the construction and management of global firms. This article describes the role and characteristics of strategic assembly in the construction and management of the global multibusiness firm, an emerging form of global organization. We present a study of Group Renault and its relationship with two key players in the lucrative and emerging market for autos in Turkey, emphasizing the coevolutionary processes through which local players enter and dominate a local market and the global parent, utilizing local learning and organization, adapts to the global environment. We conclude with a call to action for research on the relationship between the strategic logic of global assemblers and the strategies of the firms at multiple levels of analysis.
The relationship between international diversification and firm performance: Why it remains a puzzle
Authors: Wiersema Margarethe F. , Bowen Harry P.
Published: May 2011

Despite a wealth of empirical research, whether and how international diversification impacts firm performance remains one of the major unresolved research questions in the fields of strategy and international business. We propose that the lack of consensus about the nature of the international diversification–firm performance relationship results from a failure to fully grasp this complex phenomenon. Using data on trade flows of U.S. companies and their foreign subsidiaries, we provide a more focused and comprehensive perspective on the activities that define the geographic scope of U.S. companies that we hope will motivate a conceptualization of international diversification that encompasses the full range of activities that determine the geographic scope of a firm.
A theoretical assessment of the empirical literature on the impact of multinationality on performance
Authors: Hennart Jean‐François
Published: May 2011

I assess the theoretical basis for the existence of a relationship between the size of a firm's foreign footprint (its multinationality) and its performance. I argue that multinationality results from a firm's choice between coordinating internally the stages of its value chain and letting them be organized on the market and hence that there are no reasons to expect net gains from an increase or a decrease in multinationality, the only profitability impact coming from a firm having made the wrong choice and being over‐ or under‐integrated compared to the optimum. I then show that the way the literature has operationalized multinationality does not match the theoretical arguments it has advanced. I conclude that a reassessment of the literature is overdue and point to some new directions.
Confocal laser endomicroscopy in gastrointestinal diseases
Authors: Goetz Martin , Watson Alastair , Kiesslich Ralf
Published: May 2011

Confocal laser endomicroscopy (CLE) is a novel endoscopic technique permitting in vivo microscopy (optical biopsies) of the gastrointestinal mucosa. CLE has been studied in a multitude of diseases of the upper and lower gastrointestinal tract, including Barrett's esophagus, gastric inflammation and cancer, celiac disease, colorectal adenoma and carcinoma, and inflammatory bowel diseases. CLE has recently evolved and been studied for bile duct and liver imaging. CLE has shown overall high accuracy and enabled smart, targeted biopsies rather than untargeted sampling. Furthermore, the availability of real time microscopic information during endoscopy has immediate impact on therapeutic decisions and guides endoscopic interventions. CLE is also a unique tool for observation of (patho‐)physiologic events in their natural environment (functional imaging) and has been linked to molecular imaging of gastrointestinal neoplasia in vivo, thereby broadening our understanding of mucosal pathology in clinical and basic science. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Therapeutic leukapheresis in patients with leukostasis secondary to acute myelogenous leukemia
Authors: De Santis Gil Cunha , de Oliveira Luciana Correa Oliveira , Romano Lucas Gabriel Maltoni , Almeida Prado Benedito de Pina , Simoes Belinda Pinto , Rego Eduardo Magalhaes , Covas Dimas Tadeu , Falcao Roberto Passetto
Published: May 2011

Leukostasis is a relatively uncommon but potentially catastrophic complication of acute myelogenous leukemia (AML). Prompt leukoreduction is considered imperative to reduce the high mortality rate in this condition. Leukapheresis, usually associated with chemotherapy, is an established approach to diminish blast cell counts. We report a single center experience in managing leukostasis with leukapheresis. Fifteen patients with leukostasis of 187 patients with AML (8.02%) followed at our institution were treated with leukapheresis associated with chemotherapy. The procedures were scheduled to be performed on a daily basis until clinical improvement was achieved and WBC counts were significantly reduced. Overall and early mortalities, defined as that occurred in the first 7 days from diagnosis, were reported. A high proportion of our patients with leukostasis (46.66%) had a monocytic subtype AML (M4/M5, according to French‐American‐British classification). The median overall survival was 10 days, despite a significant WBC reduction after the first apheresis procedure (from 200.7 × 109/L to 150.3 × 109/L). Almost half of patients (7/15) had an early death. Therapeutic leukapheresis, associated or not to chemotherapy, is an effective approach to reduce WBC counts in patients with AML and leukostasis; however, this therapeutic procedure does not appear to change significantly the sombre prognosis observed in the majority of patients with this complication. Other forms of treatment must be found to reduce the high mortality rate related to leukostasis. J. Clin. Apheresis, 2011. © 2011 Wiley‐Liss, Inc.
(Bromodimethylsulfonium) bromide–catalyzed one‐pot three‐component synthesis of imidazo[1,2‐a]pyridines
Authors: Venkatesham R. , Manjula A. , Rao B. Vittal
Published: May 2011

(Bromodimethylsulfonium) bromide–catalyzed one‐pot multicomponent reaction of 2‐aminopyridine with aromatic aldehyde(s) and TMSCN yielding N‐benzylidene‐2‐phenylimidazo[1,2‐a]pyridines exclusively has been described. The reaction is solvent free, versatile, and takes significantly short time. J. Heterocyclic Chem., (2011).
Synthesis and reactions of pyrido[3,2,1‐jk]carbazole‐4,6‐diones
Authors: Stadlbauer Wolfgang , Dang Hoai Van , Knobloch Bernd
Published: May 2011

Pyrido[3,2,1‐jk]carbazoles 1, synthesized from carbazoles and alkyl‐ or arylmalonates, gave regioselective electrophilic substitution reactions at position 5 such as chlorination to 5‐chloro derivatives 2, nitration to 5‐nitro compounds 3, or hydroxylation to 5‐hydroxy derivatives 4. 5‐Hydroxy compounds 4 gave on treatment with strong bases ring contraction to 5, 6 or the ring opening product 7. Exchange of the chloro group in 2 with azide or amines gave the corresponding azides 8 and the 5‐amino derivatives 9 and 10. Alkylation of 1 with benzyl chloride or allyl bromide resulted in the formation of 5‐C‐alkylated products 11 together with 4‐alkyloxy derivatives 12. J. Heterocyclic Chem., 48, 1039 (2011).
Synthesis of novel spiro(indolone‐3,2′‐[1,3,4]thiadiazol)‐2‐ones and evaluation of their antidepressant and anticonvulsant activities
Authors: Hassan Alaa A. , Abdel‐Latif Fathy F. , El‐Din Ahmed M. Nour , Abdel‐Aziz Mohamed , Mostafa Sara M. , Bräse Stefan
Published: May 2011

The reaction of 3‐(dicyanomethylene)‐2‐indolone in a solution of ethanol/piperidine with 4‐substituted thiosemicarbazides forms the derivatives of 5′‐(substituted amino)‐3′H–spiro(indoline‐3,2′‐[1,3,4]thiadiazol‐2‐one. Rationales for these conversions involving the nucleophilic addition on the dicyanomethylene carbon atom are presented. The prepared compounds were evaluated each for antidepressant activity using tail suspension behavioral despair test and anticonvulsant activity against pentylenetetrazol induced seizures in mice. J. Heterocyclic Chem., (2011).
Chronological framework for the deglaciation of the Lake Michigan lobe of the Laurentide Ice Sheet from ice‐walled lake deposits
Authors: Curry Brandon , Petras Justine
Published: May 2011

A revised chronological framework for the deglaciation of the Lake Michigan lobe of the south‐central Laurentide Ice Sheet is presented based on radiocarbon ages of plant macrofossils archived in the sediments of low‐relief ice‐walled lakes. We analyze the precision and accuracy of 15 AMS 14C ages of plant macrofossils obtained from a single ice‐walled lake deposit. The semi‐circular basin is about 0.72 km wide and formed of a 4‐ to 16‐m‐thick succession of loess and lacustrine sediment inset into till. The assayed material was leaves, buds and stems of Salix herbacea (snowbed willow). The pooled mean of three ages from the basal lag facies was 18 270 ± 50 14C a BP (21 810 cal. a BP), an age that approximates the switch from active ice to stagnating conditions. The pooled mean of four ages for the youngest fossil‐bearing horizon was 17 770 ± 40 14C a BP (21 180 cal. a BP). Material yielding the oldest and youngest ages may be obtained from sediment cores located at any place within the landform. Based on the estimated settling times of overlying barren, rhythmically bedded sand and silt, the lacustrine environment persisted for about 50 more years. At a 67% confidence level, the dated part of the ice‐walled lake succession persisted for between 210 and 860 cal. a (modal value: 610 cal. a). The deglacial age of five moraines or morainal complexes formed by the fluctuating margin of the Lake Michigan lobe have been assessed using this method. There is no overlap of time intervals documenting when ice‐walled lakes persisted on these landforms. The rapid readvances of the lobe during deglaciation after the last glacial maximum probably occurred at some point between the periods of ice‐walled lake sedimentation. Copyright © 2011 John Wiley & Sons, Ltd.
Relationships between primary productivity and bottom‐water oxygenation off northwest Africa during the last deglaciation
Authors: Filipsson Helena L. , Romero Oscar E. , Stuut Jan‐Berend W. , Donner Barbara
Published: May 2011

The upwelling region off northwest Africa is one of the most productive regions in the world ocean. This study details the response of surface‐ and deep‐water environments off Mauritania, northwest Africa, to the rapid climate events of the last deglaciation, especially the Bølling–Allerød (15.5–13.5 ka BP) and Younger Dryas (13.5–11.5 ka BP). A high accumulation rate gravity core GeoB7926‐2, recovered at ∼20° N, 18° W, was analysed for the grain size distribution of the terrigenous sediment fraction, the organic carbon content, diatom and benthic foraminifera communities. Humid conditions were observed during the Bølling–Allerød with a high contribution of fluvial sediment input. During the Younger Dryas intensified trade winds caused a larger sediment input of aeolian dust from the Sahara and more intense upwelling with higher primary productivity, as indicated by high diatom concentrations. The abrupt and large increase of organic matter caused low oxygen conditions at the sea floor, reflected by the poor benthic foraminiferal fauna and the dominance of the low‐oxygen‐tolerant foraminiferal species Bulimina exilis. This is surprising since low‐oxygen conditions have not been recorded during modern times at the sea floor in this region, despite present‐day intensive upwelling and high primary productivity. After the Younger Dryas, more humid conditions returned, diatom abundance decreased and B. exilis was replaced by typical deep‐sea species as found in the region today, indicating the return of more oxygenated conditions at the sea floor. Copyright © 2011 John Wiley & Sons, Ltd.
Microwave‐accelerated derivatization prior to GC‐MS determination of sex hormones
Authors: Xu Xu , Zhao Xin , Zhang Yupu , Li Dan , Su Rui , Yang Qiuling , Li Xueyuan , Zhang Huihui , Zhang Hanqi , Wang Ziming
Published: May 2011

A new microwave‐accelerated derivatization method was developed for rapid determination of 13 natural sex hormones in feeds. Sex hormones were isolated from the sample matrix by ultrasonic extraction, followed by solid‐phase extraction, derivatized under microwave irradiation, and then analyzed directly by gas chromatography‐mass spectrometry (GC‐MS) in selective ion monitoring (SIM) mode. The key parameters affecting derivatization efficiency, including microwave irradiation time, microwave power, and reaction solvent were studied. Under microwave power of 360 W and microwave irradiation for 3 min, 13 natural sex hormones were simultaneously derivatized using heptafluorobutyric acid anhydride (HFBA) as derivatization reagent. This method was applied to the determination of 13 natural sex hormones in different feed samples, and the obtained results were compared with those obtained by the traditional thermal derivatization. The recoveries from 58.1 to 111% were obtained at sex hormone concentrations of 10–300 μg/kg with RSDs ≤12.0%. The results showed that the proposed method was fast, simple, efficient and can be applied to the determination of 13 natural sex hormones in different feed samples.
Automated pre‐column derivatization of thiolic fruit‐antibrowning agents by sequential injection coupled to high‐performance liquid chromatography using a monolithic stationary phase and an in‐loop stopped‐flow approach
Authors: Karakosta Theano D. , Tzanavaras Paraskevas D. , Themelis Demetrius G.
Published: May 2011

The present study reports the very first application of ethyl propiolate (EP) as an advantageous pre‐column derivatization reagent for the determination of thiols by liquid chromatography (LC). Cysteine (CYS), glutathione (GSH) and N‐acetylcysteine (NAC) were derivatized online under stopped‐flow conditions in a sequential injection (SI) system coupled to HPLC. The formed derivatives were separated isocratically with a monolithic stationary phase (100×4.6 mm id) and UV detected at 285 nm. Critical parameters that affected the online pre‐column derivatization reaction (e.g. the reaction time and the amount concentration of EP) and the separation (e.g. pH and the composition of the mobile phase) were investigated. The developed analytical scheme offers a total analysis time of less than 10 min, limits of detection in the range of 0.24–0.35 μmol/L and satisfactory linearity up to 200 μmol/L for all analytes. The proposed method was applied to the analysis of the selected thiols – that are often employed as antibrowning agents – in fresh fruit samples.
Optimization of the synthesis of a hyper‐crosslinked stationary phases: A new generation of highly efficient, acid‐stable hyper‐crosslinked materials for HPLC
Authors: Zhang Yu , Huang Yuming , Carr Peter W.
Published: May 2011

A new family of hyper‐crosslinked (HC) phases was recently developed for use under very aggressive conditions including those encountered in ultra‐fast, high‐temperature two‐dimensional liquid chromatography (2‐DLC). This type of stationary phase has improved acid stability compared with the most acid‐stable, commercial RPLC phases. Kinetic studies are here reported that allow optimization of reaction time and crosslinking reagent concentrations used to prepare such HC phases. We have determined that the Friedel‐Crafts chemistry used to prepare HC phases is nearly complete within about 15 min. Thus, reaction time for each step of the synthesis was greatly reduced from the multihour reactions used previously without sacrificing the stationary phases' acid stability and separation performance. Results from elemental analysis of the finished particles were combined with LC data to provide insights regarding the properties of these HC phases. This new generation of acid stable HC phases, with their attractive chromatographic properties, should be very useful in the separations of bases or biological analytes in acidic media, especially at elevated temperatures.
Multiple‐point hit distribution functions and vague convergence of related measures
Authors: Ballani Felix
Published: May 2011

For a stationary and isotropic random closed set Z in \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbb {R}^d$\end{document} it is a well‐known fact that its covariance C(t) and its spherical contact distribution function \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\widetilde{H}_s(t)$\end{document} admit at t = 0 a derivative which is a multiple of the surface intensity of Z. Within the quite general setting of gentle sets, Kiderlen and Rataj 10 show a more general result (covering both previous cases) for the derivative of a hit distribution function of Z with respect to a structuring element which only needs to be compact and contains the origin. Using this general setting the present paper introduces m‐point hit distribution functions of Z, m ⩾ 2, and shows how they are related to the mth‐order surface product density of Z. This also generalizes a result of Ballani 1 for the two‐point spherical contact distribution function of a germ‐grain model. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Large deviations for discontinuous additive functionals of symmetric stable processes
Authors: Takeda Masayoshi , Tsuchida Kaneharu
Published: May 2011

Let Xt be a symmetric stable process on d‐dimensional Euclidean space \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\mathbb {R}}^d$\end{document}. Let F(x, y) be a symmetric positive bounded function on \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}${\mathbb {R}}^d\times {\mathbb {R}}^d$\end{document} vanishing on the diagonal set and define a discontinuous additive functional by At(F) = ∑0 < s ⩽ tF(Xs −, Xs). We establish the large deviation principle of At(F)/t by employing the Gärtner‐Ellis theorem. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Rational cuspidal curve with a Galois point
Authors: Yoshihara Hisao
Published: May 2011

For a rational cuspidal curve C we study if it has a Galois point. The result is as follows: if C has an outer Galois point, then C is projectively equivalent to the curve defined by xe = yn where (e, n) = 1. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
Amphiphilic Diblock Copolymer with Dithienylethene Pendants: Synthesis and Photo‐Modulated Self‐Assembly
Authors: Chen Zhen , He Yaning , Wang Yang , Wang Xiaogong
Published: May 2011

In this work, an amphiphilic diblock copolymer (PEG43‐b‐PSDTE29) bearing photochromic dithienylethene (DTE) pendants is synthesized by reversible addition fragmentation chain transfer radical polymerization. The diblock copolymer was characterized by spectroscopic methods and gel permeation chromatography. The analyses proved the well‐defined structure and narrow molecular weight distribution of the diblock copolymer. The DTE pendants could undergo reversible photoisomerization between their open and closed forms in solution when irradiated with UV and visible light as indicated by 1H NMR and UV‐vis spectroscopy. Hollow vesicle‐like structures were formed by gradually adding deionized water to the colorless PEG43‐b‐PSDTE29open (DTE in open form) tetrahydrofuran solution. Under the same conditions, the aggregates formed in the blue PEG43‐b‐PSDTE29close (DTE in closed form) solution were colloidal spheres with solid interiors. The isomerization of DTE pendants could cause the deformation of the vesicle‐like structures. The above results demonstrate a kind of novel photo‐modulated self‐assembly behavior of the amphiphilic diblock copolymer, which could be used for drug‐delivery and other applications.

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Influence of the metabolic syndrome on leptin and leptin receptor in breast cancer
Authors: Carroll Paul A. , Healy Laura , Lysaght Joanne , Boyle Terry , Reynolds John V. , Kennedy M. John , Pidgeon Graham , Connolly Elizabeth M.
Published: May 2011

Obesity and its associated metabolic syndrome (MetS) are recognized risk factors for breast cancer. The molecular basis for this association remains largely unknown. Adipokines, in particular leptin and adiponectin, are thought to form part of the mechanism linking obesity with cancer through their altered expression/production either systemically (endocrine pathway) or locally (paracrine/autocrine pathway). Using quantitative PCR, mRNA expression of adiponectin (AdipoQ) and leptin (Ob) in mammary adipose tissue (MAT), intratumoral leptin and associated ligand receptors (ObR, AdipoR1, and AdipoR2) was examined in 77 patients with complete anthropomorphic and serological data. Expression of Ob in MAT, and ObR in matched tumor tissue was significantly higher in patients with MetS compared to obese only or normal weight cancer patients (P < 0.005). There was no difference in intratumoral leptin adiponectin or its ligand receptors in the same groups. Individual features of MetS correlated with Ob and ObR expression, but not obesity markers (BMI, waist circumference). mRNA expression of leptin (Ob) and ObR, in adipose tissue and matched tumor samples, respectively, appear to be associated with obesity status in breast cancer. Increasing insulin resistance is a predominant feature of this higher Ob/ObR expression observed. These novel data indicate that the MetS may be an amenable risk factor for breast cancer. © 2011 Wiley‐Liss, Inc.