bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthetic transformations of dimethyl perfluoro-4-methyl-2-pentenedioate
Authors: Svoboda Jiří , Paleta Oldřich , Dědek Václav
Published: August 2011

Reaction of the title compound I with methanolic sodium methoxide proceeded with decarboxylation and substitution of the vinylic fluorine atom, the resulting product being methyl 2,4,5,5,5-pentafluoro-3-methoxy-2-pentenoate (II). Compound I reacted with chlorine to give dimethyl 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethylpentanedioate (III) which was selectively hydrolyzed to potassium 1-methyl 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethylpentanedioate (IV). This ester salt was transformed in two steps into methyl 2,3-dichloro-4-fluoroformylhexafluoropentanoate (VIII). Pyrolysis of IV afforded methyl 2-chlorohexafluoro-3-pentanoate (V). Reduction of the diester III with sodium borohydride led to 3-chloro-2,3,4-trifluoro-2-hydroxymethyl-4-trifluoromethyloxolane (IX) and 2,3-dichloro-2,3,4-trifluoro-4-trifluoromethyl-1,5-pentane diol (X).
Conformation of branched polypeptides based on poly(L-lysine). Effect of the ionic strength and of the presence of alcohols
Authors: Votavová Hana , Hudecz Ferenc , Šponar Jaroslav , Bláha Karel , Szekerke Mária
Published: August 2011

CD spectra of branched polypeptides based on poly(L-lysine) containing in the side chains approximately, 3, 5 and 8.5 DL-alanine residues or 3 DL-alanine residues and another terminal L-amino acid were measured at pH 7.4, and in the uncharged state in various ionic strengths, and also in water-methanol and water-trifluoroethanol mixtures. At pH 7.4 and in low ionic strength (0.02M and 0.2M-NaCl) the polypeptides assume an unordered conformation, except for the L-leucine containing polypeptide, which is helical to a considerable extent. Increase of the ionic strength to 2.0M-NaCl leads to the formation of the α-helical structure. In the uncharged state all polypeptides are at least partly helical. The content of the α-helix increases with increasing ionic strength and depends also on the nature of the side chain. Formation of the α-helix is supported by the presence of L-leucine and L-proline, some limitation of the α-helix formation by histidine is manifested mainly in low ionic strength. The presence of methanol and trifluoroethanol has an effect similar to the increase of ionic strength, i.e. increases the α-helix content.
Effects of 17β-estradiol and antioxidant administration on oxidative stress and insulin resistance in ovariectomized rats
Authors: Abbas Amr M. , Elsamanoudy Ayman Z.
Published: August 2011

The prevalence of insulin resistance syndrome increases during menopause with the overproduction of reactive oxygen species and impairment of the free radical scavenger function. Therefore, we investigated the effects of 17β-estradiol (E2) and vitamin E, as an antioxidant, on lipid peroxidation and antioxidant levels in the brain cortex and liver of ovariectomized rats as well as on insulin resistance in those rats. Forty female Sprague–Dawley rats, 3 months of age and weighing 231.5 ± 9.4 g, were divided into 4 groups: sham, ovariectomized (OVX), OVX treated with E2 (40 µg/kg subcutaneously), and OVX treated with E2 and vitamin E (100 mg/kg intraperitoneally). The 4 groups received the appropriate treatment every day for 8 weeks. Levels of glutathione, glutathione peroxidase, superoxide dismutase , catalase, and malondialdehyde in the brain cortex and liver of ovariectomized rats were measured. Also, fasting plasma insulin, glucose, and homeostatis model assessment of insulin resistance (HOMA-IR) were determined. Malondialdehyde increased and antioxidants (glutathione, glutathione peroxidase, catalase, superoxide dismutase) decreased in the brain cortex and liver of OVX rats. Also, fasting glucose, insulin, and HOMA-IR increased in OVX rats. E2 and E2 plus vitamin E decreased malondialdehyde and increased antioxidants in the brain cortex and liver of OVX rats. Moreover, they decreased fasting glucose, insulin, and HOMA-IR in ovariectomized rats. This study demonstrates that E2 and E2 plus vitamin E supplementation to OVX rats may improve insulin resistance, strengthen the antioxidant system, and reduce lipid peroxidation.
SCHWARZSCHILD–DE SITTER BLACK HOLE FROM ENTROPIC VIEWPOINT
Authors: EE CHANG-YOUNG , EUNE MYUNGSEOK , KIMM KYOUNGTAE , LEE DAEHO
Published: August 2011

In a Schwarzschild–de Sitter space, we consider an equipotential surface which consists of two holographic screens. Adapting the Bousso–Hawking's reference point of vanishing force, we divide the space into two regions, which are from the reference point to each holographic screen. These two regions can be treated as independent thermodynamical systems, because the Bousso–Hawking reference point with zero temperature behaves like a thermally insulating wall. The entropy obtained in this way agrees with the conventional results: (i) when the holographic screens lie at the black hole and cosmological horizons, (ii) in the Nariai limit.
LEPTOGENESIS FROM SOFT SUPERSYMMETRY BREAKING: SOFT LEPTOGENESIS
Authors: FONG CHEE SHENG , GONZALEZ-GARCIA M. C. , NARDI ENRICO
Published: August 2011

Soft leptogenesis is a scenario in which the cosmic baryon asymmetry is produced from a lepton asymmetry generated in the decays of heavy sneutrinos (the partners of the singlet neutrinos of the seesaw) and where the relevant sources of CP violation are the complex phases of soft supersymmetry-breaking terms. We explain the motivations for soft leptogenesis, and review its basic ingredients: the different CP-violating contributions, the crucial role played by thermal corrections, and the enhancement of the efficiency from lepton flavor effects. We also discuss the high temperature regime T > 107 GeV in which the cosmic baryon asymmetry originates from an initial asymmetry of an anomalous R-charge, and soft leptogenesis reembodies in R-genesis.
SOME REMARKS ON DARK ENERGY MODELS
Authors: CAI RONG-GEN
Published: August 2011

In this talk I classify dark energy models existing in the literatures into three classes. The first one is to ascribe the cosmic acceleration to modifications of general relativity at cosmological scales. The second one is due to the backreaction of perturbations, or say, the effect of inhomogeneity of the universe. The third one is some exotic component in the universe, which appears in the right hand side of Einstein's field equations. For each class I demonstrate some examples.
PHANTOM CROSSING IN VIABLE f(R) THEORIES
Authors: BAMBA KAZUHARU , GENG CHAO-QIANG , LEE CHUNG-CHI
Published: August 2011

We review the equation of state for dark energy in modified gravity theories. In particular, we summarize the generic feature of the phantom divide crossing in the past and future in viable f(R) gravity models.
f(R) GRAVITY AND ITS COSMOLOGICAL IMPLICATIONS
Authors: MOTOHASHI HAYATO , STAROBINSKY ALEXEI A. , YOKOYAMA JUN'ICHI
Published: August 2011

We have investigated the evolution of a homogeneous isotropic background of the Universe and inhomogeneous subhorizon matter density perturbations in viable f(R) models of present dark energy and cosmic acceleration analytically and numerically. It is found that viable f(R) models generically exhibit recent crossing of the phantom boundary w DE = -1. Furthermore, it is shown that the growth index of perturbations depends both on time and wavenumber. This anomalous growth may explain properties of the observational matter power spectrum from the SDSS data and can also partially counteract the spectrum suppression by massive neutrinos making larger values of the total sum of neutrino rest-masses possible.
COSMOLOGICAL AND SOLAR-SYSTEM TESTS OF f(R) MODIFIED GRAVITY
Authors: GU JE-AN
Published: August 2011

We, the LeCosPA Dark Energy Working Group, are investigating dark energy and modified gravity as possible origins of the accelerating expansion of the present universe. In this paper we report our recent progress in modified gravity, in particular the work in arXiv:1009.3488 on the cosmological and the solar-system tests of the f(R) theory of modified gravity. In this work we found that the solar-system test ruled out the frequently studied w = -1 designer f(R) models which are cosmologically distinct from the ΛCDM model. In addition, under the cosmological test many designer f(R) models suffer a fine-tuning problem about the choice of the initial condition of f(R).
V-PARTICLE AGAIN?
Authors: ZHU SHOU-HUA
Published: August 2011

This talk is mainly based on our previous work.1 We will investigate the possibility of detecting light long-lived particle (LLP) produced by high energy cosmic ray colliding with atmosphere. The LLP may penetrate the atmosphere and decay into a pair of muons near/in the neutrino telescope. Such muons can be treated as the detectable signal for neutrino telescope. The particle with such behavior is very similar with that of the first observed strange particle in cosmic ray events, which was coined historically as "V-particle" in some literature. This study is motivated by recent cosmic electron/positron observations which suggest the existence of O(TeV) dark matter and new light O(GeV) particle. It indicates that dark sector may be complicated, and there may exist more than one light particle, for example the dark gauge boson A′ and associated dark Higgs boson h′. In this work, we discuss the scenario with A′ heavier than h′ and h′ is treated as LLP. Based on our numerical estimation, we find that the large volume neutrino telescope IceCube has the capacity to observe several tens of di-muon events per year for favorable parameters if the decay length of LLP can be comparable with the depth of atmosphere. The challenge here is how to suppress the muon background induced by cosmic rays and atmospheric neutrinos.
SCALAR DARK MATTER AND STANDARD MODEL WITH FOUR GENERATIONS
Authors: HE XIAO-GANG , HO SHU-YU , TANDEAN JUSAK , TSAI HO-CHIN
Published: August 2011

This talk is based on the previous paper [X. G. He et al., Phys. Rev. D82 (2010) 035016]. We consider a scalar dark-matter model, the SM4+D, consisting of the standard model with four generations (SM4) and a real gauge-singlet scalar called darkon, D, as the weakly interacting massive particle (WIMP) dark-matter (DM) candidate. We explore constraints on the darkon sector of the SM4+D from WIMP DM direct-search experiments, and from the decay of a B meson into a kaon plus missing energy. Since the darkon-Higgs interaction may give rise to considerable enhancement of the Higgs invisible decay mode, the existence of the darkon could lead to the weakening or evasion of some of the restrictions on the Higgs mass in the presence of fourth-generation quarks. In addition, it can affect the flavor-changing decays of these new heavy quarks into a lighter quark and the Higgs boson, as the Higgs may subsequently decay invisibly. Therefore, we also study these flavor-changing neutral transitions involving the darkon, as well as the corresponding top-quark decay t → cDD, some of which may be observable at the Tevatron or LHC and thus provide additional tests for the SM4+D.
MODEL-INDEPENDENT STUDIES OF DARK MATTER
Authors: CHEN CHUAN-REN
Published: August 2011

The excess in cosmic-ray positrons and electrons observed by PAMELA, ATIC, PPB-BET and Fermi can be explained by dark matter decay or annihilation. On the other hand, the negative results from CDMS II and XENON direct detections of dark matter put an upper limit on the elastic-scattering cross section between dark matter and nucleon. We adopted model-independent approaches to study dark matter in cosmic-ray electrons, gamma-ray, relic density, direct detection experiments and LHC. We studied the distribution of the cosmic-ray electron flux observed at the Earth and found that it can reflect the initial energy spectrum of electrons generated from dark matter decay or annihilation even after propagation. We also derive constraints on the decay rate of dark matter into various two-body final states using Fermi and HESS gamma-ray data. We found that the μ+μ- or τ+τ- final state is favored in order to simultaneously explain electron excess and meet all gamma-ray constraints. Finally, we examined various tree-level induced operators of dimension six and constrain them using the current experimental data, including the WMAP data of the relic abundance and CDMS II direct detection of the spin-independent scattering. The implication of LHC search is also explored.
INFLATION AFTER WMAP
Authors: NG KIN-WANG
Published: August 2011

Recent measurements of the large-scale cosmic microwave background anisotropy made by the Wilkinson Microwave Anisotropy Probe (WMAP) mission indicate a reflection asymmetry, an axis of evil, a low quadrupole, and a few multipoles deviated from predicted in the cold dark matter model with a cosmological constant. All of these may give us a hint about the physics of inflation during the first few e-folds or during the inflating period. Efforts taken along this direction will be reviewed and our recent work will be discussed.
HILLTOP SUPERNATURAL INFLATION: HOW TO OBTAIN ns = 0.96
Authors: LIN CHIA-MIN
Published: August 2011

In this talk, I will explain how to reduce the spectral index of supernatural inflation to be ns = 0.96 naturally by using the idea of hilltop inflation.
ASPECTS OF HOŘAVA–LIFSHITZ COSMOLOGY
Authors: SARIDAKIS EMMANUEL N.
Published: August 2011

We review some general aspects of Hořava–Lifshitz cosmology. Formulating it in its basic version, we extract the cosmological equations and we use observational data in order to constrain the parameters of the theory. Through a phase–space analysis we extract the late-time stable solutions, and we show that bouncing and cyclic behavior can arise naturally. Concerning the effective dark energy sector we show that it can describe the phantom phase without the use of a phantom field. However, performing a detailed perturbation analysis, we see that Hořava–Lifshitz gravity in its basic version, suffers from instabilities. Therefore, suitable generalizations are required in order for this novel theory to be a candidate for the description of nature.
The Seoul National University Business School: Managing Global Challenge and Cultural Change
Authors: Park Jinsoo , Choi Minjung
Published: August 2011

The Seoul National University Business School (SNUBS) consists of two sub-organizations, the College of Business Administration (CBA) and the Graduate School of Business (GSB). The former, taking control of undergraduate, master, and doctorate programs, has been the main body of the SNU Business School. The latter, newly established at the dawn of Master of Business Administration (MBA) education in the country, is to manage the "Global MBA" program which is aimed at achieving global recognition in World's business school rankings.

As Seoul National University has been administered by the government, faculty and staff were not accustomed to a different type of institution conforming to the North American standard, for example, getting evaluated by the class they taught. A few professors were negative about the new program. However, most of the faculty tried to be positive and proactive about creating new curricula, once they understood the rationale behind the need of MBA education in Seoul National University.

As the Global MBA was about to be included in the rankings list, the global competition will be inevitable and ever challenging. If Seoul National University was aimed at reaching number 10 within ten years, the school had far more way to go despite its unique characteristics and strong advantages. To make matters more demanding, competitors from all over the world, particularly Asian institutes, were exerting themselves and going up the ladders rapidly.

Considering these changes and challenges, what are the strategic issues and constraints faced by the SNUBS? What have they done in the past and what should they do in the future? What should be given strategic priority? The case will help readers to dive deep into these management questions and analysis.
Exploiting Service Usage Information for Optimizing Server Resource Management
Authors: Totok Alexander , Karamcheti Vijay
Published: August 2011

It is often difficult to tune the performance of modern component-based Internet services because: (1) component middleware are complex software systems that expose several independently tuned server resource management mechanisms; (2) session-oriented client behavior with complex data access patterns makes it hard to predict what impact tuning these mechanisms has on application behavior; and (3) component-based Internet services themselves exhibit complex structural organization with requests of different types having widely ranging execution complexity. In this article we show that exposing and using detailed information about how clients use Internet services enables mechanisms that achieve two interconnected goals: (1) providing improved QoS to the service clients, and (2) optimizing server resource utilization. To differentiate among levels of service usage (service access) information, we introduce the notion of the
service access attribute
and identify four related groups of service access attributes, encompassing different aspects of service usage information, ranging from the high-level structure of client web sessions to low-level fine-grained information about utilization of server resources by different requests. To show how the identified service usage information can be collected, we implement a request profiling infrastructure in the JBoss Java application server. In the context of four representative service management problems, we show how collected service usage information is used to improve service performance, optimize server resource utilization, or to achieve other problem-specific service management goals.
Anomaly Detection in Dynamic Systems Using Weak Estimators
Authors: Zhan Justin , Oommen B. John , Crisostomo Johanna
Published: August 2011

Anomaly detection involves identifying observations that deviate from the normal behavior of a system. One of the ways to achieve this is by identifying the phenomena that characterize “normal” observations. Subsequently, based on the characteristics of data learned from the “normal” observations, new observations are classified as being either “normal” or not. Most state-of-the-art approaches, especially those which belong to the family of parameterized statistical schemes, work under the assumption that the underlying distributions of the observations are stationary. That is, they assume that the distributions that are learned during the training (or learning) phase, though unknown, are not time-varying. They further assume that the same distributions are relevant even as new observations are encountered. Although such a “stationarity” assumption is relevant for many applications, there are some anomaly detection problems where stationarity cannot be assumed. For example, in network monitoring, the patterns which are learned to represent normal behavior may change over time due to several factors such as network infrastructure expansion, new services, growth of user population, and so on. Similarly, in meteorology, identifying anomalous temperature patterns involves taking into account seasonal changes of normal observations. Detecting anomalies or outliers under these circumstances introduces several challenges. Indeed, the ability to adapt to changes in nonstationary environments is necessary so that anomalous observations can be identified even with changes in what would otherwise be classified as “normal” behavior. In this article we propose to apply a family of weak estimators for anomaly detection in dynamic environments. In particular, we apply this theory to spam email detection. Our experimental results demonstrate that our proposal is both feasible and effective for the detection of such anomalous emails.
8-Phenylthio-adenines stimulate the expression of steroid hydroxylases, Cav3.2 Ca2+channels, and cortisol synthesis by a cAMP-independent mechanism
Authors: Enyeart Judith A. , Liu Haiyan , Enyeart John J.
Published: August 2011

The regulation of cortisol synthesis and the expression of genes coding for steroidogenic proteins by 8-substituted cAMP and 8-substituted adenine derivatives were studied in bovine adrenal zona fasciculata (AZF) cells. At concentrations of 10–50 μM, 8-(4-chlorophenylthio)-cAMP (8CPT-cAMP), but not the poorly hydrolyzable Sp-8CPT-cAMP, stimulated large increases in cortisol synthesis and CYP17 mRNA expression. Of the three Epac (exchange protein activated by cAMP)-specific cAMP analogs, 8CPT-2′-OMe-cAMP, but not 8HPT-2′-OMe-cAMP or 8MeOPT-2′-OMe-cAMP, induced mRNAs for CYP17 and CYP11a1 steroid hydroxylases and stimulated cortisol synthesis. 8-Substituted adenine derivatives (10–200 μM), including 8PT-adenine, 8MeOPT-adenine, and 8CPT-adenine, stimulated similar large, concentration-dependent, and reversible increases in cortisol synthesis and steroid hydroxylase gene expression, whereas 8Br-adenine was ineffective. The phenylthio-adenine derivatives produced additive effects on cortisol synthesis when applied to AZF cells in combination with 8Br-cAMP. In contrast, no additivity was observed for these three compounds when used in combination with ACTH. 8PT-adenine did not activate PKA or inhibit DNA synthesis by AZF cells. 8PT-adenine-stimulated cortisol secretion and CYP17 steroid hydroxylase mRNA expression were potently inhibited by diphenyl-butylpiperidine T-type Ca2+antagonists. In AZF cells, 8PT-adenine and 8MeOPT-adenine induced the expression of both CACNA1H mRNA and associated Cav3.2 Ca2+current. These results indicate that 8-chloro (but not 8-hydroxy- or 8-methoxy-)-phenylthio-cAMP analogs are converted to an active metabolite, 8CPT-adenine, that induces the expression of genes coding for steroidogenic proteins in bovine AZF cells. Other PT-adenine analogs also potently stimulate cortisol synthesis through the same unidentified signaling pathway that requires the expression of functional Cav3.2 Ca2+channels. These phenylthio-adenine compounds and ACTH may stimulate cortisol synthesis through the same cAMP-independent mechanism.
B-Cell Depletion Therapy in Systemic Sclerosis: Experimental Rationale and Update on Clinical Evidence
Authors: Daoussis Dimitrios , Liossis Stamatis-Nick C. , Yiannopoulos Georgios , Andonopoulos Andrew P.
Published: August 2011

Systemic sclerosis (SSc) is a systemic rheumatic disease with poor prognosis since therapeutic options are limited. Recent evidence from animal models suggests that B-cells may be actively involved in the fibrotic process. B-cells from tight skin mice, an animal model of scleroderma, display a “hyperresponsive” phenotype; treatment with rituximab (RTX) significantly attenuates skin fibrosis in this animal model. In humans, B-cell infiltration is a prominent finding in most lung biopsies obtained from patients with SSc-associated interstitial lung disease. Several open label studies have assessed the clinical efficacy of RTX in SSc. In most patients skin fibrosis improved; lung function either improved or remained stable. Definite conclusions regarding the clinical efficacy of RTX in SSc cannot be drawn but further exploration with a multicenter, randomized study is warranted.
Calcifying Ghost Cell Odontogenic Cyst: Report of a Case and Review of Literature
Authors: Sonone Archana , Sabane V. S. , Desai Rajeev
Published: August 2011

The calcifying ghost cell odontogenic cyst (CGCOC) was first described by Gorlin et al. in 1962. Calcifying ghost cell odontogenic cyst is comparatively rare in occurrence, constituting about 0.37% to 2.1% of all odontogenic tumors. The most notable features of this pathologic entity are histopathological features which include a cystic lining demonstrating characteristic “Ghost” epithelial cells with a propensity to calcify. In addition, the CGCOC may be associated with other recognized odontogenic tumors, most commonly odontomas. There are variants of CGCOC according to clinical, histopathological, and radiological characteristics. Therefore a proper categorization of the cases is needed for better understanding of the pathogenesis of each variant. Here, we report a classical case of calcifying odontogenic cyst along with a brief review of literature.
Moldless PEGDA-Based Optoelectrofluidic Platform for Microparticle Selection
Authors: Yang Shih-Mo , Yu Tung-Ming , Liu Ming-Huei , Hsu Long , Liu Cheng-Hsien
Published: August 2011

This paper reports on an optoelectrofluidic platform which consists of the organic photoconductive material, titanium oxide phthalocyanine (TiOPc), and the photocrosslinkable polymer, poly (ethylene glycol) diacrylate (PEGDA). TiOPc simplifies the fabrication process of the optoelectronic chip due to requiring only a single spin-coating step. PEGDA is applied to embed the moldless PEGDA-based microchannel between the top ITO glass and the bottom TiOPc substrate. A real-time control interface via a touch panel screen is utilized to select the target 15 μm polystyrene particles. When the microparticles flow to an illuminating light bar, which is oblique to the microfluidic flow path, the lateral driving force diverts the microparticles. Two light patterns, the switching oblique light bar and the optoelectronic ladder phenomenon, are designed to demonstrate the features. This work integrating the new material design, TiOPc and PEGDA, and the ability of mobile microparticle manipulation demonstrates the potential of optoelectronic approach.
Low-Temperature Strengths and Ductility of Various Tungsten Sheets
Authors: Hiraoka Yutaka , Kurishita Hiroaki
Published: August 2011

We used three kinds of tungsten sheets in this study. First, we examined microstructure such as grain size distribution using an optical microscope. Secondly, we carried out three-point bend tests at temperatures between about 290 and 500 K. Then, we examined fracture surface of a failed specimen using a scanning electron microscope. Lastly, by analyzing all these results, we evaluated apparent intergranular and transgranular fracture strengths and discussed strengths and ductility of tungsten. Additionally, we compared mechanical properties of tungsten with those of molybdenum.
Synthesis of Plant-Mediated Silver Nanoparticles UsingDioscorea batatasRhizome Extract and Evaluation of Their Antimicrobial Activities
Authors: Nagajyothi P. C. , Lee K. D.
Published: August 2011

The eco-friendly synthesis of nanoparticles through various biological means helps to explore various plants for their ability to synthesize silver nanoparticles (AgNPs). Here we have synthesized AgNPs by using rhizome extract ofDioscorea batatasat as well as room temperature (). AgNPs were characterized under UV-vis spectrophotometer, SEM, FTIR, XRD, and EDX. The antimicrobial activity of AgNPs was evaluated on gram positive (B. substilisandS. aureus), gram negative (E. coli), and fungi (S. cerivisaeandC. albicans). At room temperature,S. cerivisaeandC. albicanswere found to be more susceptible to AgNPs than at .
Experimental Study of Nonequilibrium Electrodeposition of Nanostructures on Copper and Nickel for Photochemical Fuel Cell Application
Authors: Shanmugam Rajesh K. , Gan Bo J. , Zhang Boya , Su Lusheng , Gan Yong X.
Published: August 2011

To increase the performance of photochemical fuel cells, nonequilibrium electrodeposition has been performed on Cu and Ni to make photosensitive anodes. Processing parameters including electrolyte concentration, and electrode potential were studied using cyclic voltammetry. Scanning electron microscopy (SEM) and X-ray Spectroscopy (EDS) were performed to understand the formation of the nanostructures during the nonequilibrium deposition of copper fractals. An increase in the deposition rate was observed with the increase in electrolyte concentration (from 0.05 M to 1.0 M). Similar trend was found when the cathode potential was decreased from −0.5 V to −4.5 V. The effect of substrate material was also examined. Porous fractal structures on copper were achieved, while the deposited material showed high density of surface cracks on nickel. The fractal structures deposited on copper electrode with the increased surface area were converted into copper oxide by oxidation in air. Such oxide samples were made into anodes for photochemical fuel cell application. We demonstrated that an increase in the magnitude of open circuit output voltage is associated with the increase in the fractal surface area under the ultraviolet irradiation test conditions. However, the electrodeposited fractals on nickel showed very limited increase in the magnitude of open circuit voltage.
Application of Quantum Dots in Biological Imaging
Authors: Jin Shan , Hu Yanxi , Gu Zhanjun , Liu Lei , Wu Hai-Chen
Published: August 2011

Quantum dots (QDs) are a group of semiconducting nanomaterials with unique optical and electronic properties. They have distinct advantages over traditional fluorescent organic dyes in chemical and biological studies in terms of tunable emission spectra, signal brightness, photostability, and so forth. Currently, the major type of QDs is the heavy metal-containing II-IV, IV-VI, or III-V QDs. Silicon QDs and conjugated polymer dots have also been developed in order to lower the potential toxicity of the fluorescent probes for biological applications. Aqueous solubility is the common problem for all types of QDs when they are employed in the biological researches, such asin vitroandin vivoimaging. To circumvent this problem, ligand exchange and polymer coating are proven to be effective, besides synthesizing QDs in aqueous solutions directly. However, toxicity is another big concern especially forin vivostudies. Ligand protection and core/shell structure can partly solve this problem. With the rapid development of QDs research, new elements and new morphologies have been introduced to this area to fabricate more safe and efficient QDs for biological applications.
A Semi-Deterministic Channel Model for VANETs Simulations
Authors: Ledy Jonathan , Boeglen Hervé , Poussard Anne-Marie , Hilt Benoît , Vauzelle Rodolphe
Published: August 2011

Today's advanced simulators facilitate thorough studies on Vehicular Ad hoc NETworks (VANETs). However the choice of the physical layer model in such simulators is a crucial issue that impacts the results. A solution to this challenge might be found with a hybrid model. In this paper, we propose a semi-deterministic channel propagation model for VANETs called UM-CRT. It is based on CRT (Communication Ray Tracer) and SCME—UM (Spatial Channel Model Extended—Urban Micro) which are, respectively, a deterministic channel simulator and a statistical channel model. It uses a process which adjusts the statistical model using relevant parameters obtained from the deterministic simulator. To evaluate realistic VANET transmissions, we have integrated our hybrid model in fully compliant 802.11 p and 802.11 n physical layers. This framework is then used with the NS-2 network simulator. Our simulation results show that UM-CRT is adapted for VANETs simulations in urban areas as it gives a good approximation of realistic channel propagation mechanisms while improving significantly simulation time.
Generation of Optical Vortex Arrays Using Single-Element Reversed-Wavefront Folding Interferometer
Authors: Singh Brijesh Kumar , Singh G. , Senthilkumaran P. , Mehta D. S.
Published: August 2011

Optical vortex arrays have been generated using simple, novel, and stable reversed-wavefront folding interferometer. Two new interferometric configurations were used for generating a variety of optical vortex lattices. In the first interferometric configuration one cube beam splitter (CBS) was used in one arm of Mach-Zehnder interferometer for splitting and combining the collimated beam, and one mirror of another arm is replaced by second CBS. At the output of interferometer, three-beam interference gives rise to optical vortex arrays. In second interferometric configuration, a divergent wavefront was made incident on a single CBS which splits and combines wavefronts leading to the generation of vortex arrays due to four-beam interference. It was found that the orientation and structure of the optical vortices can be stably controlled by means of changing the rotation angle of CBS.
Tumor-Derived Autophagosome Vaccine: Induction of Cross-Protective Immune Responses against Short-lived Proteins through a p62-Dependent Mechanism
Authors: Twitty Christopher G. , Jensen Shawn M. , Hu Hong-Ming , Fox Bernard A.
Published: August 2011

Purpose: Tumor-specific antigens of 3-methylcholanthrene (MCA)-induced sarcomas were defined by the narrow immune responses they elicited, which uniquely rejected the homologous tumor, with no cross-reactions between independently derived syngeneic MCA-induced tumors. This study examines whether an autophagosome-enriched vaccine derived from bortezomib-treated sarcomas can elicit an immune response that cross-reacts with other unique sarcomas.

Experimental Design: Mice were vaccinated with either MCA-induced sarcomas or autophagosomes derived from those tumors and later challenged with either homologous or nonhomologous sarcomas. In addition, 293 cells expressing a model antigen were used to understand the necessity of short-lived proteins (SLiP) in this novel vaccine. These findings were then tested in the sarcoma model. Autophagosomes were characterized by Western blotting and fluorescent microscopy, and their ability to generate immune responses was assessed in vitro by carboxyfluorescein succinimidyl ester dilution of antigen-specific T cells and in vivo by monitoring tumor growth.

Results: In contrast to a whole-cell tumor vaccine, autophagosomes isolated from MCA-induced sarcomas treated with a proteasome inhibitor prime T cells that cross-react with different sarcomas and protect a significant proportion of vaccinated hosts from a nonhomologous tumor challenge. Ubiquitinated SLiPs, which are stabilized by proteasome blockade and delivered to autophagosomes in a p62/sequestosome-dependent fashion, are a critical component of the autophagosome vaccine, as their depletion limits vaccine efficacy.

Conclusion: This work suggests that common short-lived tumor-specific antigens, not physiologically available for cross-presentation, can be sequestered in autophagosomes by p62 and used as a vaccine to elicit cross-protection against independently derived sarcomas. Clin Cancer Res; 17(20); 6467–81. ©2011 AACR.
Mammary Gland Density Predicts the Cancer Inhibitory Activity of the N-3 to N-6 Ratio of Dietary Fat
Authors: Zhu Zongjian , Jiang Weiqin , McGinley John N. , Prokopczyk Bogden , Richie John P. , El Bayoumy Karam , Manni Andrea , Thompson Henry J.
Published: August 2011

This study investigated the effect of a broad range of dietary ratios of n-3:n-6 fatty acids on mammary gland density and mammary cancer risk. Cancer was induced in female rats by N-methyl-N-nitrosourea. Purified diet that provided 30% of dietary kilocalories from fat was formulated to contain ratios of n-3:n-6 fatty acids from 25:1 to 1:25. Mammary gland density was determined by digital analysis, fatty acids by gas chromatography/flame ionization detection, and other plasma analytes via ELISA. Mammary gland density was reduced dose dependently at n-3:n-6 ratios from 1:1 to 25:1 (r = −0.477, P = 0.038), with a 20.3% decrease of mammary gland density between n-3:n-6 of 1:1 versus 25:1, P < 0.001. Mammary carcinogenesis was inhibited in the absence or presence of tamoxifen (1 mg/kg diet) in a manner predicted by mammary gland density. Plasma n-3 fatty acid concentrations failed to increase above an n-3:n-6 ratio of 5:1, and changes in specific plasma n-3 or n-6 fatty acids were not predictive of mammary gland density or cancer inhibitory activity. A strong reciprocal effect of the n-3:n-6 ratio on plasma leptin (decreased, P = 0.005) and adiponectin (increased, P < 0.001) was observed indicating adipose tissue function was modulated. However, neither cytokine was predictive of mammary gland density. Plasma insulin-like growth factor I (IGF-I) decreased with increasing dietary n-3:n-6 ratio (P = 0.004) and was predictive of the changes in mammary gland density (r = 0.362, P < 0.005). These findings indicate that (i) mammary gland density predicted the carcinogenic response, (ii) the n-3:n-6 ratio exerts effects in the presence or absence of hormonal regulation of carcinogenesis, and (iii) signaling pathways regulated by IGF-I are potential targets for further mechanistic investigation. Cancer Prev Res; 4(10); 1675–85. ©2011 AACR.
TMS to the Lateral Occipital Cortex Disrupts Object Processing but Facilitates Scene Processing
Authors: Mullin Caitlin R. , Steeves Jennifer K. E.
Published: August 2011

The study of brain-damaged patients and advancements in neuroimaging have lead to the discovery of discrete brain regions that process visual image categories, such as objects and scenes. However, how these visual image categories interact remains unclear. For example, is scene perception simply an extension of object perception, or can global scene “gist” be processed independently of its component objects? Specifically, when recognizing a scene such as an “office,” does one need to first recognize its individual objects, such as the desk, chair, lamp, pens, and paper to build up the representation of an “office” scene? Here, we show that temporary interruption of object processing through repetitive TMS to the left lateral occipital cortex (LO), an area known to selectively process objects, impairs object categorization but surprisingly facilitates scene categorization. This result was replicated in a second experiment, which assessed the temporal dynamics of this disruption and facilitation. We further showed that repetitive TMS to left LO significantly disrupted object processing but facilitated scene processing when stimulation was administered during the first 180 msec of the task. This demonstrates that the visual system retains the ability to process scenes during disruption to object processing. Moreover, the facilitation of scene processing indicates disinhibition of areas involved in global scene processing, likely caused by disrupting inhibitory contributions from the LO. These findings indicate separate but interactive pathways for object and scene processing and further reveal a network of inhibitory connections between these visual brain regions.
The Rapid Extraction of Gist—Early Neural Correlates of High-level Visual Processing
Authors: Oppermann Frank , Hassler Uwe , Jescheniak Jörg D. , Gruber Thomas
Published: August 2011

The human cognitive system is highly efficient in extracting information from our visual environment. This efficiency is based on acquired knowledge that guides our attention toward relevant events and promotes the recognition of individual objects as they appear in visual scenes. The experience-based representation of such knowledge contains not only information about the individual objects but also about relations between them, such as the typical context in which individual objects co-occur. The present EEG study aimed at exploring the availability of such relational knowledge in the time course of visual scene processing, using oscillatory evoked gamma-band responses as a neural correlate for a currently activated cortical stimulus representation. Participants decided whether two simultaneously presented objects were conceptually coherent (e.g., mouse–cheese) or not (e.g., crown–mushroom). We obtained increased evoked gamma-band responses for coherent scenes compared with incoherent scenes beginning as early as 70 msec after stimulus onset within a distributed cortical network, including the right temporal, the right frontal, and the bilateral occipital cortex. This finding provides empirical evidence for the functional importance of evoked oscillatory activity in high-level vision beyond the visual cortex and, thus, gives new insights into the functional relevance of neuronal interactions. It also indicates the very early availability of experience-based knowledge that might be regarded as a fundamental mechanism for the rapid extraction of the gist of a scene.
When “It” Becomes “Mine”: Attentional Biases Triggered by Object Ownership
Authors: Turk David J. , van Bussel Kim , Brebner Joanne L. , Toma Andreea S. , Krigolson Olav , Handy Todd C.
Published: August 2011

Previous research has demonstrated that higher-order cognitive processes associated with the allocation of selective attention are engaged when highly familiar self-relevant items are encountered, such as one's name, face, personal possessions and the like. The goal of our study was to determine whether these effects on attentional processing are triggered on-line at the moment self-relevance is established. In a pair of experiments, we recorded ERPs as participants viewed common objects (e.g., apple, socks, and ketchup) in the context of an “ownership” paradigm, where the presentation of each object was followed by a cue indicating whether the object nominally belonged either to the participant (a “self” cue) or the experimenter (an “other” cue). In Experiment 1, we found that “self” ownership cues were associated with increased attentional processing, as measured via the P300 component. In Experiment 2, we replicated this effect while demonstrating that at a visual–perceptual level, spatial attention became more narrowly focused on objects owned by self, as measured via the lateral occipital P1 ERP component. Taken together, our findings indicate that self-relevant attention effects are triggered by the act of taking ownership of objects associated with both perceptual and postperceptual processing in cortex.
When One Person's Mistake Is Another's Standard Usage: The Effect of Foreign Accent on Syntactic Processing
Authors: Hanulíková Adriana , van Alphen Petra M. , van Goch Merel M. , Weber Andrea
Published: August 2011

How do native listeners process grammatical errors that are frequent in non-native speech? We investigated whether the neural correlates of syntactic processing are modulated by speaker identity. ERPs to gender agreement errors in sentences spoken by a native speaker were compared with the same errors spoken by a non-native speaker. In line with previous research, gender violations in native speech resulted in a P600 effect (larger P600 for violations in comparison with correct sentences), but when the same violations were produced by the non-native speaker with a foreign accent, no P600 effect was observed. Control sentences with semantic violations elicited comparable N400 effects for both the native and the non-native speaker, confirming no general integration problem in foreign-accented speech. The results demonstrate that the P600 is modulated by speaker identity, extending our knowledge about the role of speaker's characteristics on neural correlates of speech processing.
Role of Broca's Area in Implicit Motor Skill Learning: Evidence from Continuous Theta-burst Magnetic Stimulation
Authors: Clerget Emeline , Poncin William , Fadiga Luciano , Olivier Etienne
Published: August 2011

Complex actions can be regarded as a concatenation of simple motor acts, arranged according to specific rules. Because the caudal part of the Broca's region (left Brodmann's area 44, BA 44) is involved in processing hierarchically organized behaviors, we aimed to test the hypothesis that this area may also play a role in learning structured motor sequences. To address this issue, we investigated the inhibitory effects of a continuous theta-burst TMS (cTBS) applied over left BA 44 in healthy subjects, just before they performed a serial RT task (SRTT). SRTT has been widely used to study motor skill learning and is also of interest because, for complex structured sequences, subjects spontaneously organize them into smaller subsequences, referred to as chunks. As a control, cTBS was applied over the vertex in another group, which underwent the same experiment. Control subjects showed both a general practice learning effect, evidenced by a progressive decrease in RT across blocks and a sequence-specific learning effect, demonstrated by a significant RT increase in a pseudorandom sequence. In contrast, when cTBS was applied over left BA 44, subjects lacked both the general practice and sequence-specific learning effects. However, surprisingly, their chunking pattern was preserved and remained indistinguishable from controls. The present study indicates that left BA 44 plays a role in motor sequence learning, but without being involved in elementary chunking. This dissociation between chunking and sequence learning could be explained if we postulate that left BA 44 intervenes in high hierarchical level processing, possibly to integrate elementary chunks together.
The Neurotopography of Written Word Production: An fMRI Investigation of the Distribution of Sensitivity to Length and Frequency
Authors: Rapp Brenda , Dufor Olivier
Published: August 2011

This research is directed at charting the neurotopography of the component processes of the spelling system by using fMRI to identify the neural substrates that are sensitive to the factors of lexical frequency and word length. In spelling, word frequency effects index orthographic long-term memory whereas length effects, as measured by the number of letters, index orthographic working memory (grapheme buffering). Using the task of spelling to dictation in the scanner, we found a highly differentiated neural distribution of sensitivity to the factors of length and lexical frequency, with areas exhibiting sensitivity to length but not frequency and vice versa. In addition, a direct comparison with the results of a previous study [Rapp, B., & Lipka, K. The literate brain: The relationship between spelling and reading. Journal of Cognitive Neuroscience, 23, 1180–1197, 2011] that used a very different spelling task yielded a converging pattern of findings regarding the neural substrates of the central components of spelling. Also, with regard to relationship between reading and spelling, we replicated previous functional neuroimaging studies that have shown overlapping regions of activation in the left posterior inferior frontal gyrus and midfusiform gyrus for word reading and spelling.
Visual Processing of Contour Patterns under Conditions of Inattentional Blindness
Authors: Pitts Michael A. , Martínez Antígona , Hillyard Steven A.
Published: August 2011

An inattentional blindness paradigm was adapted to measure ERPs elicited by visual contour patterns that were or were not consciously perceived. In the first phase of the experiment, subjects performed an attentionally demanding task while task-irrelevant line segments formed square-shaped patterns or random configurations. After the square patterns had been presented 240 times, subjects' awareness of these patterns was assessed. More than half of all subjects, when queried, failed to notice the square patterns and were thus considered inattentionally blind during this first phase. In the second phase of the experiment, the task and stimuli were the same, but following this phase, all of the subjects reported having seen the patterns. ERPs recorded over the occipital pole differed in amplitude from 220 to 260 msec for the pattern stimuli compared with the random arrays regardless of whether subjects were aware of the patterns. At subsequent latencies (300–340 msec) however, ERPs over bilateral occipital-parietal areas differed between patterns and random arrays only when subjects were aware of the patterns. Finally, in a third phase of the experiment, subjects viewed the same stimuli, but the task was altered so that the patterns became task relevant. Here, the same two difference components were evident but were followed by a series of additional components that were absent in the first two phases of the experiment. We hypothesize that the ERP difference at 220–260 msec reflects neural activity associated with automatic contour integration whereas the difference at 300–340 msec reflects visual awareness, both of which are dissociable from task-related postperceptual processing.