bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mercury (II) alters mitochondrial activity of monocytes at sublethal doses via oxidative stress mechanisms
Authors: Messer Regina L.W. , Lockwood Petra E. , Tseng Wan Y. , Edwards Kerry , Shaw Melissa , Caughman Gretchen B. , Lewis Jill B. , Wataha John C. 
Published: August 2005

AbstractThe perennial controversy about the safety of mercury in dental amalgams has adversely affected the availability and the quality of dental care. Chronic Hg(II) blood concentrations above 300 nM are known to alter function of the nervous system and the kidney. However, the effects of blood concentrations of 10 to 75 nM, far more common in the general population, are not clear and mechanisms of any effects are not known. The monocyte is an important potential target of Hg(II) because of its critical role in directing inflammatory and immune responses. In the current study we tested the hypothesis that concentrations of Hg(II) of 10 to 300 nM alter monocyte activity via a redox‐dependent mechanism. Mitochondrial activity was used to establish inhibitory concentrations of Hg(II) following 6 to 72 h of exposures to THP1 human monocytic cells. Then subinhibitory concentrations were applied, and total glutathione levels and reactive oxygen species (ROS) were measured. Antioxidants [N‐acetyl cysteine, (NAC); Na2SeO3, (Se)] and a pro‐oxidant (tert‐butylhydroquinone, tBHQ) were used to support the hypothesis that Hg(II) effects were redox‐mediated. After 72 h of exposure, 20 μM of Hg(II) inhibited monocytic mitochondrial activity by 50%. NAC mitigated Hg(II)‐induced mitochondrial suppression only at concentrations of greater than 10 μM, but Se had few effects on Hg‐induced mitochondrial responses. tBHQ significantly enhanced mitochondrial suppression at higher Hg(II) concentrations. Hg(II) concentrations of 75 and 300 nM (0.075 and 0.30 μM, respectively) significantly increased total glutathione levels, and NAC mitigated these increases. Se plus Hg(II) significantly elevated Hg‐induced total cellular glutathione levels. Increased ROS levels were not detected in monocytes exposed to mercury. Hg(II) acts in monocytic cells, at least in part, through redox‐mediated mechanisms at concentrations below those commonly associated with chronic mercury toxicity, but commonly occurring in the blood of some dental patients. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005
Phosphoinositide 3‐kinaseγ (PI3Kγ) controls L‐type calcium current (ICa,L) through its positive modulation of type‐3 phosphodiesterase (PDE3)
Authors: Marcantoni Andrea , Levi Renzo Cesare , Gallo Maria Pia , Hirsch Emilio , Alloatti Giuseppe 
Published: August 2005

AbstractThe modulation of L‐type calcium current (ICa,L) is mainly due to mediators acting through activation of G protein‐coupled receptors (GPCR) and different protein kinases; among them, phosphoinositide 3‐kinaseγ (PI3Kγ) has been recently discovered to play an important role in the regulation of cardiac contractility and β‐adrenergic signal transduction. Recent reports have demonstrated that, in the heart, different subtypes of β‐adrenergic receptors are coupled to both Gi and/or Gs proteins. While β1‐adrenergic receptors (β1‐AR) couple only to Gs and evoke a strong ICa,L, β2‐adrenergic receptors (β2‐AR) can activate both Gs and Gi proteins and trigger only a limited ICa,L. Here we demonstrate that (i) PI3Kγ−/− ventricular myocytes are characterized by an higher basal ICa,L density, even if the responsiveness of adenylyl cyclase to Forskolin is comparable to that observed in PI3Kγ+/+ cardiomyocytes; (ii) both in basal conditions and after β‐AR stimulation, the activity of phosphodiesterase (PDE) type 3 depends on PI3Kγ; (iii) in PI3Kγ−/− cardiac myocytes, specific stimulation of β2‐AR is followed by a increase in ICa,L stronger than in wild‐type controls. Taken together, our results suggest that the higher values of ICa,L observed both in basal conditions and after β‐AR stimulation in PI3Kγ−/− ventricular myocytes are mainly due to a positive modulation of PDE3 activity exerted by PI3Kγ. As observed in PI3Kγ−/− neonatal cardiomyocytes, cells lacking PI3Kγ are more sensitive to stimulation of β2‐adrenergic receptors. J. Cell. Physiol. 206: 329–336, 2006. © 2005 Wiley‐Liss, Inc.
Myostatin auto‐regulates its expression by feedback loop through Smad7 dependent mechanism
Authors: Forbes Davanea , Jackman Mark , Bishop Amy , Thomas Mark , Kambadur Ravi , Sharma Mridula 
Published: August 2005

AbstractMyostatin, a secreted growth factor, is a member of the TGF‐β superfamily and an inhibitor of myogenesis. Previously, we have shown that myostatin gene expression is regulated at the level of transcription and that myostatin is a downstream target gene of MyoD. Here we show that myostatin gene expression is auto‐regulated by a negative feedback mechanism. Northern blot analysis indicated that there are relatively higher levels of myostatin mRNA in the biceps femoris muscle of cattle that express a non‐ functional myostatin allele (Belgian Blue) as compared to normal cattle. In contrast, addition of exogenous myostatin decreases endogenous myostatin mRNA. Consistent with this result, wild type myostatin protein is able to repress myostatin promoter activity via Activin type IIb receptor (ActRIIB) and ALK5 (P < 0.001). However, non‐functional myostatin (Piedmontese) failed to repress the myostatin promoter suggesting that myostatin auto‐regulates its promoter by negative feedback inhibition. Auto‐regulation by myostatin appears to be signaled through Smad7, since the expression of the inhibitory Smad7 is induced by myostatin and the over‐expression of Smad7 in turn inhibits the myostatin promoter activity (P < 0.001). In contrast down regulation of Smad7 by siRNA results in increased myostatin mRNA indicating that Smad7 is a negative regulator of myostatin gene expression. Consistent with these results, a decrease in Smad7 mRNA and concomitant increase in myostatin expression is seen in myotubes that express non functional myostatin. In addition, interference with myostatin signaling prevents the induction of Smad7 promoter activity by myostatin. Based on these results, we propose that myostatin auto‐regulates its gene expression through a Smad7 dependent mechanism in myogenic cells. © 2005 Wiley‐Liss, Inc.
Optical properties of a novel nonlinear chromophore doped polymer and application for two‐photon microfabrication
Authors: Guo Fuquan , Guo Rui , Jiang Zhongwei , Zhang Qijin , Huang Wenhao , Guo Bin 
Published: August 2005

AbstractOne‐photon and two‐photon optical properties of a novel nonlinear chromophore 4,4′‐bis(triphenylamino‐trans‐styryl)‐biphenyl (BTSBP) doped polymethylmethacryate (PMMA) are presented. Two‐photon absorption (TPA) cross section (δ) of BTSBP was determined through the two‐photon‐induced fluorescence method by using Rhodamine B as a standard at the excitation wavelength of 800 nm pumped with a Ti:sapphire femtosecond laser. A three‐dimensional (3D) photonic crystal with a period of 4 µm was fabricated indicating BTSBP is an efficient photoinitiator for two‐photon microfabrication. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laser‐reflectometry monitoring of the GaN growth by MOVPE using SiN treatment: study and simulation
Authors: Fitouri H. , Benzarti Z. , Halidou I. , Boufaden T. , Jani B. El 
Published: August 2005

AbstractThe SiN treatment of the sapphire substrate for GaN growth induces a spectacular effect on the in situ reflectometry monitoring signal. Different growth modes are observed. The evolution of the reflectometry signal is simulated by the scattering theory approximation. The point‐by‐point analysis reveals that the roughness (rms) increases in the first region where the growth mode is dominated by the formation of isolated and three‐dimensional hillocks. The rms attains a maximum value exceeding that authorized by the Rayleigh criteria. Another approach based on the effective medium approximation is used to simulate the entire reflectometry signal evolution. An effective refractive index and a growth rate profile are determined. The results obtained are in accordance with the observations done by the in situ ellipsometry monitoring. We have also studied the evolution of the defined recovery time as a function of the SiH4 flow rate and the SiN duration. Based on the concept of a nano‐epitaxial mask, induced by the SiN treatment of the sapphire surface, we have proposed a schematic model of the GaN growth that explains the recovery‐time behavior. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Behaviour of the 3C–SiC(100) c(2 × 2) (C‐terminated) and 3 × 2 (Si‐rich) surface reconstructions upon initial H2/CH4 microwave plasma exposures
Authors: Portail M. , Saada S. , Delclos S. , Arnault J. C. , Soukiassian P. , Bergonzo Ph. , Chassagne Th. , Leycuras A. 
Published: August 2005

AbstractWe present a comparative study of C‐terminated and Si‐rich 3C–SiC(100) surfaces exposed to a H2/CH4 microwave plasma used in diamond growth. Each surface is characterized before and after short plasma exposures using LEED, XPS and STM techniques. In both cases, a 5 minutes plasma exposure led to a 1 × 1 LEED pattern associated with a slight oxygen contamination as evidenced by XPS. However, upon additional annealings, the two surfaces exhibit very different behaviors. For the Si‐terminated 3 × 2 surface, a 1 × 1 → 2 × 1 transition occurring at 1173 K is observed while the initial c(2 × 2) surface reconstruction is restored at 1323 K for the C‐terminated surface. Furthermore, the XPS measurements show a correlation between oxygen surface release and LEED transitions. An atomic arrangement is observed by STM for the C‐terminated surface (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of phosphorus‐doped diamond using organophosphorus gases
Authors: Kato Hiromitsu , Yamasaki Satoshi , Okushi Hideyo 
Published: August 2005

AbstractPhosphorus‐doped diamond films were grown by plasma‐enhanced chemical vapor deposition using organophosphorus gases, tertiarybutylphosphine (TBP) and trimethylphosphine (TMP). The electronic properties are characterized based on secondary ion mass spectroscopy, Hall‐effect, and cathodoluminescence measurements and compared with data deduced for samples which have been doped using PH3. The technical potential of P‐doping using TBP is discussed and the high potential of TBP and TMP as alternative P precursors for P‐doping of diamond is shown. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA attachment to nanocrystalline diamond films
Authors: Wenmackers S. , Christiaens P. , Daenen M. , Haenen K. , Nesládek M. , van deVen M. , Vermeeren V. , Michiels L. , Ameloot M. , Wagner P. 
Published: August 2005

AbstractA biochemical method to immobilize DNA on synthetic diamond for biosensor applications is developed. Nanocrystalline diamond is grown using microwave plasma‐enhanced chemical vapour deposition. On the hydrogen‐terminated surface 10‐undecenoic acid is tethered photochemically under 254 nm illumination, followed by 1‐ethyl‐3‐[3‐dimethylaminopropyl]carbodiimide crosslinker‐mediated attachment of amino modified DNA. The attachment is functionally confirmed by comparison of supernatant fluorescence and gel electrophoresis. The linking procedure allowed for 35 denaturation and rehybridisation steps. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Inelastic light scattering of hydrogen containing open‐cage fullerene ATOCF
Authors: Rafailov P. M. , Thomsen C. , Bassil A. , Komatsu K. , Bacsa W. 
Published: August 2005

AbstractWe report Raman measurements on Aza‐Thia Open‐Cage Fullerene (ATOCF) containing hydrogen molecules. We analyze the spectral bands of empty and H2‐filled ATOCF and compare them with Raman spectra ofpristine C60. We find a large number of additional bands due to the lower symmetry of ATOCF and detect the hydrogen stretching vibration of the caged H2 molecules. Depending on their environment significant band broadening is observed.magnified imageATOCF molecule containing H2.(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progresses in III‐nitride distributed Bragg reflectors and microcavities using AlInN/GaN materials
Authors: Carlin J.‐F. , Zellweger C. , Dorsaz J. , Nicolay S. , Christmann G. , Feltin E. , Butté R. , Grandjean N. 
Published: August 2005

AbstractWe propose to use lattice‐matched AlInN/GaN to replace the Al(Ga)N/GaN material system for III‐nitride Bragg reflectors, despite the poor material quality of AlInN reported until very recently. We report an improvement of AlInN material that allowed for successful fabrication of a microcavity light emitting diode, a distributed Bragg reflector with 99.4% reflectivity and microcavities with a quality factor over 800. These results establish state‐of‐the‐art values for III‐nitrides, and announce the future importance of AlInN in GaN‐based optoelectronics. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High efficiency planar MCLEDs
Authors: Joray R. , Stanley R. P. , Ilegems M. 
Published: August 2005

AbstractThe physics of microcavities have been a subject of intense study over the past 25 years. This work stimulated a large body of experimental and theoretical work on the optimization of the light extraction properties of light‐emitting diodes. Not only has this led to the current high efficiency microcavity LEDs but also to the high brightness LEDs based on other approaches, which are presently available on the market. An overview of the state of the art of planar semiconductor microcavity LEDs will be presented. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Special issue: Semiconductor Microcavities
Authors: Deveaud Benoit 
Published: August 2005

AbstractThis special issue of physica status solidi (b) honours the work of Marc Ilegems, Director of the Institute for Micro‐ and Optoelectronics at the Swiss Federal Institute of Technology (Ecole Polytechnique Fédérale) in Lausanne. Many colleagues and friends have contributed articles to this issue which presents important developments in the field of microcavity‐polariton physics such as parametric amplification, Bose–Einstein condensation of exciton‐polaritons as well as growth and characterization of microcavity structures.Guest Editor of the present issue is Benoit Deveaud, who is head of a research group for optical studies in condensed matter, especially in the ultrafast time domain. His focus of research is the understanding of the interaction of light with semiconductors in general and with semiconductor nanostructures in particular.The cover picture of the current issue depicts a computed Rayleigh figure showing the letters M. I., the initials of Marc Ilegems. For more details on resonant Rayleigh scattering induced by artificial or natural defects see the article by Ciuti and Carusotto [1].
Recent Developments in Nanofabrication Using Focused Ion Beams
Authors: Tseng Ampere A. 
Published: August 2005

AbstractFocused ion beam (FIB) technology has become increasingly popular in the fabrication of nanoscale structures. In this paper, the recent developments of the FIB technology are examined with emphasis on its ability to fabricate a wide variety of nanostructures. FIB‐based nanofabrication involves four major approaches: milling, implantation, ion‐induced deposition, and ion‐assisted etching of materials; all these approaches are reviewed separately. Following an introduction of the uniqueness and strength of the technology, the ion source and systems used for FIB are presented. The principle and specific techniques underlying each of the four approaches are subsequently studied with emphasis on their abilities of writing structures with nanoscale accuracy. The differences and uniqueness among these techniques are also discussed. Finally, concluding remarks are provided where the strength and weakness of the techniques studied are summarized and the scopes for technological improvement and future research are recommended.
Synthesis of Fullerene‐Like Tantalum Disulfide Nanoparticles by a Gas‐Phase Reaction and Laser Ablation
Authors: Schuffenhauer Christoph , Parkinson Bruce A. , Jin‐Phillipp Neng Yun , Joly‐Pottuz Lucile , Martin Jean‐Michel , Popovitz‐Biro Ronit , Tenne Reshef 
Published: August 2005

AbstractMotivated by the discovery of the C60 molecule (buckminsterfullerene), the search for inorganic counterparts of this closed‐cage nanostructure started in 1992 with the discovery of nested fullerene‐like nanoparticles of WS2. Inorganic fullerene‐like (IF) materials have since been found in numerous two‐dimensional compounds and are available in a variety of shapes that offer major applications such as in lubricants and nanocomposites. Various synthetic methodologies have been employed to achieve the right conditions for the constricted or templated growth needed for the occurrence of this new phase. In this study, IF‐TaS2 is produced from a volatile chloride precursor in the gas phase and in small yield by room temperature laser ablation both in argon and in liquid CS2. For the gas‐phase reaction, a high yield of IF nanoparticles was obtained between 400 and 600 °C with a low concentration of the precursor gas. The average size and the yield of the IF‐TaS2 nanoparticles decrease with temperature. Above 600 °C, IF nanoparticles were found in low yields and at sizes below 20 nm. The stability of the IF nanoparticles produced by the gas‐phase reaction is discussed in the light of two existing theoretical models. Laser ablation in argon leads to IF nanoparticles filled with clusters of TaS2. Agglomeration of the nanoparticles can be avoided by laser ablation in liquid CS2.
Structural determinants of joint venture performance
Authors: Hennart Jean‐François , Zeng Ming 
Published: August 2005

AbstractIn this paper we sketch a theory of the motives of alliances and joint ventures, deduce the reasons for their instability, and discuss the structural factors that affect their performance. We argue that the alliance literature, by focusing on knowledge internalization, has given short shrift to the empirically more important motive of knowledge access, a strategy we call ‘cooperative specialization’. Cooperative specialization allows firms to pool their competencies with those of their partner and to specialize in what they do best, but it also exposes them to opportunism. We discuss how such opportunism can be checked by proper structural design. The main issue is how to reward partners for their contribution to the alliance, and two main contractual forms are possible, ex ante and residual‐sharing contracts, a category which includes equity joint ventures. Focusing on the latter, we investigate how various structural solutions can be used to align the interests of the joint venture partners.
Alliance structure and process: will the two research streams ever meet in alliance research?
Authors: Contractor Farok J 
Published: August 2005

AbstractThe objective of this paper is to offer some reflections on the state of research in the alliance field and to comment on the Hennart and Zeng, and Salk papers, which are part of this issue. The implicit questions addressed are whether structure or process matters more in explaining alliance performance, whether academic research under‐represents processual and behavioral studies on the motivations and mindsets of alliance executives, and whether the two research streams can ever meet. Doing research in the alliance field is a particularly difficult task because of the wide range of structures or organizational forms, a large variety of motivations for alliance formation, and multiplicity of roles played by alliance partners. Since the underlying question is whether structure or process matter more in explaining performance or success, the paper first reviews our current ability to measure alliance performance. It then reviews alliance structure research, as well as process‐oriented, micro‐level studies to date, and suggests areas where our understanding is still to be developed. The paper concludes by outlining research domains which combine the two research streams, (1) In terms of how alliance structure can affect post‐formation partner behaviors and joint managerial processes, and (2) How negotiations processes at the formation stage influence the alliance structure that the parties agree upon.
EDA for HLM: Visualization when Probabilistic Inference Fails
Authors: Bowers Jake , Drake Katherine W. 
Published: August 2005

Nearly all hierarchical linear models presented to political science audiences are estimated using maximum likelihood under a repeated sampling interpretation of the results of hypothesis tests. Maximum likelihood estimators have excellent asymptotic properties but less than ideal small sample properties. Multilevel models common in political science have relatively large samples of units like individuals nested within relatively small samples of units like countries. Often these level-2 samples will be so small as to make inference about level-2 effects uninterpretable in the likelihood framework from which they were estimated. When analysts do not have enough data to make a compelling argument for repeated sampling based probabilistic inference, we show how visualization can be a useful way of allowing scientific progress to continue despite lack of fit between research design and asymptotic properties of maximum likelihood estimators.Somewhere along the line in the teaching of statistics in the social sciences, the importance of good judgment got lost amid the minutiae of null hypothesis testing. It is all right, indeed essential, to argue flexibly and in detail for a particular case when you use statistics. Data analysis should not be pointlessly formal. It should make an interesting claim; it should tell a story that an informed audience will care about, and it should do so by intelligent interpretation of appropriate evidence from empirical measurements or observations.—Abelson, 1995, p. 2With neither prior mathematical theory nor intensive prior investigation of the data, throwing half a dozen or more exogenous variables into a regression, probit, or novel maximum-likelihood estimator is pointless. No one knows how they are interrelated, and the high-dimensional parameter space will generate a shimmering pseudo-fit like a bright coat of paint on a boat's rotting hull.—Achen, 1999, p. 26
Melanocytic nevi are associated with neurofibromas in neurofibromatosis, type I, but not sporadic neurofibromas. A study of 226 cases*
Authors: Ball Nigel J. , Kho Grace T. 
Published: August 2005

Background:  Neurofibromatosis, type 1, is associated with cutaneous melanin pigmentation, but an association with ordinary melanocytic nevi has not been described.Methods:  This retrospective case‐control study was designed to see if neurofibromas in patients with neurofibromatosis, type 1 (NF‐1) differ from sporadic neurofibromas (SN) in their incidence of associated melanocytic nevi and other histologic features. Slides from 114 NF‐1 were compared with 112 SN and 300 intradermal melanocytic nevi (IDN).Results:  Small lentiginous melanocytic nevi were identified over 13 NF‐1 (11%) but no SN (P = 0.0002). Compared with other NF‐1, NF‐1 with nevi were more frequently associated with melanocytic hyperplasia, giant melanosomes and diffuse neurofibroma (P < 0.03). Compared with SN, NF‐1 were also more frequently associated with melanocytic hyperplasia, lentigo simplex‐like changes, diffuse neurofibroma and plexiform neurofibroma (P < 0.001). Sebaceous hyperplasia (14%), dermal elastosis (9%), lipomatous change (8%), epithelial cysts (4%) and keratin granulomas or folliculitis (3%) were not significantly different in prevalence between NF‐1, SN and the control group of IDN.Conclusions:  This study suggests that there is a difference in the potential for melanocytic proliferation in NF‐1 compared with SN. NF‐1, SN and IDN are associated with a similar range of incidental histologic changes.