bluuebunny/crossref_metadata_2025 huggingface dataset:
THE KAONIC ATOMS 'PUZZLE': WHAT NEXT?
Authors: FRIEDMAN ELIAHU
Published: February 2011

The 'kaonic atoms puzzle' is a conflict between phenomenological potentials and potentials constructed from more fundamental approaches. Whereas the former are typically 180 MeV deep, the latter are less than 50 MeV deep. Extrapolating to neutron star densities only the former could sustain kaon condensation. Likewise only the deep potential could support the recently proposed clusters of nucleons strongly bound by an antikaon. Careful re-analyses of the world's data on kaonic atoms could not suggest an explanation to the puzzle. Repeating some of the 30-40 years old experiments seems the only way to proceed. We propose to repeat measurements for a small group of kaonic atom species, namely C , Si , Ni , Sn and Pb . It is found that fits to the data for any four of these five targets reproduce all the features obsereved in fits to the full set of 23 targets.
RECENT RESULTS ON CP-VIOLATION AT THE BABAR AND BELLE B-FACTORIES
Authors:   ON BEHALF OF THE BABAR AND BELLE COLLABORATIONS, NEAL HOMER
Published: February 2011

New results on CP violation measurements performed on [Formula: see text] events collected at the Υ(4S) in upto 432 fb-1 of data at the BABAR experiment and upto 770 fb-1 of data collected at the Belle experiment. The measurements provide new constraints on the unitarity triangle angles γ and β. The measurements presented include: results from BABAR and Belle on CPV using Dalitz plot analyses, measurements of the CKM angle γ using a GLW analysis of B → DK± decays and from using B → D*°K- decays and results on yCP using D° mixing.
TESTS OF SYMMETRIES WITH NUCLEI
Authors: NAVILIAT-CUNCIC OSCAR
Published: February 2011

I review here the status of tests of discrete symmetries in nuclear beta decay, including neutron decay. The focus is given on tests of maximal parity violation, tests of time reversal invariance as well as searches for parity and time reversal invariant exotic interactions. Along with the most sensitive results, I present also some recent achievements of precision beta decay experiments as well as selected ongoing project.
MESON PRODUCTION AND BARYON RESONANCES AT CLAS
Authors: BURKERT VOLKER D.
Published: February 2011

I give a brief overview of the exploration of baryon properties in meson photo- and electroproduction. These processes provide ample information for the study of electromagnetic couplings of baryon resonances and to search for states, yet to be discovered. The CLAS detector, combined with the use of energy-tagged polarized photons and polarized electrons, as well as polarized targets and the measurement of recoil polarization, provide the tools for a comprehensive nucleon resonance program. I briefly present the status of this program, prospects for the next few years, and plans for the Jefferson Lab 12 GeV upgrade.
HADRON PHYSICS AT J-PARC — CURRENT STATUS AND FUTURE PROSPECTS
Authors: NARUKI MEGUMI
Published: February 2011

The J-PARC Hadron Facility is designed as a multipurpose experimental facility for a wide range of particle and nuclear physics programs, aiming to provide the world highest intensity secondary beams. The first primary beam has been successfully extracted and transported to the beam dump on January 2009. Currently three secondary beam lines come into operation, and the new beam line will be completed in the early summer of 2010. Various experimental programs are proposed at each beamline and some of them are preparing to start physics run. Most of the experimental researches concerns the studies of hypernuclei and searches for new hadronic states. As the first experiment at the J-PARC Hadron Facility, search for the Θ+ pentaquark via pion-induced hadronic reaction will be performed in the autumn of 2010. The current status and recent results of the commissioning for the beam line are reported.
STUDY ON THE TWO-PHOTON TRANSITION FROM ψ(2S) TO J/ψ AT BESIII
Authors:   ON BEHALF OF THE BESIII COLLABORATION, LU XIAO-RUI
Published: February 2011

Within the chamonium-threshold QCD theory, the two-photon spectroscopies of charmonia will provide the unique test on the non-perturbative treatment. With the high luminosity and excellent detector in the BESIII experiment, the two-photon transition from ψ(2S) to J/ψ is firstly observed and the preliminary result of the measurement of the branching fraction is given.
CHARMONIUM RESONANCES IN e+e- ANNIHILATION CROSS SECTIONS AROUND THE ψ(4415) REGION
Authors: SEGOVIA J. , ENTEM D. R. , FERNÁNDEZ F.
Published: February 2011

We calculate the exclusive cross section for the processes e+e- → D0D-π+ and e+e- → D0D*-π+ using a constituent quark model which successfully describes the [Formula: see text] sector.
SPIN EFFECTS IN DIFFRACTIVE CHARMONIA PRODUCTION
Authors: PASECHNIK ROMAN , SZCZUREK ANTONI , TERYAEV OLEG
Published: February 2011

We consider exclusive double diffractive production of polarised axial-vector χc(1+) and tensor χc(2+) charmonia in proton-(anti)proton collisions at Tevatron energy. The corresponding amplitudes for these processes are derived within the kt-factorisation approach. Contributions from different polarisation states of axial-vector and tensor charmonia are quantified. Corresponding experimental consequences are discussed.
INVESTIGATION OF THE CHARGE SYMMETRY CONSERVING REACTION dd → 3He nπ0 WITH WASA-at-COSY
Authors:   FOR THE WASA-at-COSY COLLABORATION, PODKOPAŁ PAWEŁ
Published: February 2011

One of the key experiments of the physics program of WASA-at-COSY is the determination of the p- wave contributions to the Charge Symmetry breaking amplitude in the reaction dd → 4 He π0 at 1.2 GeV/c beam momentum. As a first step towards realisation of this goal the Charge Symmetry conserving reaction dd → 3 Hen π0 was measured. For an overall theoretical analysis of CSB reactions in terms of Chiral Perturbation Theory this reaction channel will be used to gain information on the deuteron-deuteron initial state interaction for s- and p- wave pion production.
KAONIC HELIUM MEASUREMENTS IN THE SIDDHARTA EXPERIMENT
Authors:   FOR THE SIDDHARTA COLLABORATION, SIRGHI D. L. , BAZZI M. , BEER G. , BOMBELLI L. , BRAGADIREANU A. M. , CARGNELLI M. , CORRADI G. , CURCEANU (PETRASCU) C. , D'UFFIZI A. , FIORINI C. , FRIZZI T. , GHIO F. , GIROLAMI B. , GUARALDO C. , HAYANO R. S. , ILIESCU M. , ISHIWATARI T. , IWASAKI M. , KIENLE P. , SANDRI P. LEVI , LONGONI A. , LUCHERINI V. , MARTON J. , OKADA S. , PIETREANU D. , PONTA T. , RIZZO A. , VIDAL A. ROMERO , SCORDO A. , SHI H. , SIRGHI F. , TATSUNO H. , TUDORACHE A. , TUDORACHE V. , DOCE O. VAZQUEZ , WIEDMANN E. , ZMESKAL J.
Published: February 2011

The SIDDHARTA experiment (SIlicon Drift Detector for Hadronic Atom Research by Timing Application) had the aim to perform kaonic atoms X-ray transitions measurements, to better understand aspects of the low-energy QCD in the strangeness sector. The experiment combined the excellent low-energy kaon beam generated at DAΦNE, allowing to use gaseous targets, with excellent fast X-rays detectors: Silicon Drift Detectors. SIDDHARTA was installed on DAΦNE in autumn 2008 and took data till late 2009. Apart of the kaonic hydrogen and kaonic deuterium measurements, we have performed the kaonic helium transitions to the 2p level ( L -lines) measurements: for the first time in a gaseous target for helium4 and for the first time ever for kaonic helium3. The interest for such type of measurement was rather high, being it triggered by two reasons: the so-called "kaonic helium puzzle" (even if this was solved by KEK-PS E570 experiment, but a cross-check was useful) and some theoretical predictions of possible high energy shift (at the level of 10 eV). In this paper the preliminary results for the measurements to the 2p level ( L -series) for kaonic helium4 and kaonic helium3 are presented.
ON SCALAR MESONS FROM THE COMBINED ANALYSIS OF MULTI-CHANNEL ππ SCATTERING AND J/ψ DECAYS
Authors: SUROVTSEV YU. S. , BYDŽOVSKÝ P. , GUTSCHE T. , LYUBOVITSKIJ V. E.
Published: February 2011

In the combined analysis data on multi-channel ππ scattering and J/ψ decays, a status and parameters of the scalar mesonic resonances are obtained.
STRUCTURE OF Λ*(1405) AND THE Λ*-MESON-BARYON COUPLING CONSTANTS
Authors: AN C. S. , SAGHAI B.
Published: February 2011

Within an extended chiral constituent quark model, three- and five-quark structure of the S01 resonance Λ(1405) is investigated with respect to the coupling constants [Formula: see text] and [Formula: see text]. Our findings corroborate with about 50% of five-quark admixture in the Λ(1405) needed in reproducing the strong decay width, ΓΛ(1405)→(Σπ)°.
EXCLUSIVE PRODUCTION OF VECTOR MESONS IN pp AND $p\bar p$ COLLISIONS
Authors: CISEK ANNA , SCHÄFER WOLFGANG , SZCZUREK ANTONI
Published: February 2011

Photoproduction process γp → Vp has been mesured recently at HERA. We compare our results with the recent data. The corresponding amplitude is used to predict the cross section for exclusive production in pp and [Formula: see text] collisions. Here we present distribution in rapidity and transverse momentum of vector mesons for Tevatron and LHC energies. The absorption effects are discussed.
BAYESIAN MODEL SELECTION FOR ELECTROMAGNETIC KAON PRODUCTION ON THE NUCLEON
Authors: DE CRUZ L. , IRELAND D. G. , VANCRAEYVELD P. , RYCKEBUSCH J.
Published: February 2011

We present the results of a Bayesian analysis of a Regge model for K+Λ photoproduction. The model is based on the exchange of K+(494) and K*+(892) trajectories in the t-channel. For different prior widths, we find decisive Bayesian evidence (Δ ln Ƶ ≈ 24) for a K+Λ photoproduction Regge model with a positive vector coupling and a negative tensor coupling constant for the K*+(892) trajectory, and a rotating phase factor for both trajectories. Using the χ2 minimization method, one could not draw this conclusion from the same dataset.
THE ETA-MESON PHOTOPRODUCTION ON PROTON
Authors: DONOVAL JAN , BYDŽOVSKÝ PETR
Published: February 2011

We have performed the tree-level calculations of the eta meson photoproduction on proton for photon laboratory energies between 714 and 1500 MeV. The resonances N (1535), N (1710), N (1650), N (1440) and N (1520) were assumed. The form factors were introduced in the hadron vertices to involve the structure of hadrons. The influence of various form factor recipes was investigated. In order to keep gauge invariance, the appropriate contact term was introduced. The parameters of our model (coupling constants, cutoffs) were fitted to recent experimental data of the cross sections and some polarization observables.
DIFFRACTIVE DISSOCIATION OF 190 GeV/c π- INTO π-π+π- FINAL STATES AT COMPASS
Authors:   FOR THE COMPASS COLLABORATION, GRUBE BORIS
Published: February 2011

We present results from a Partial-Wave Analysis (PWA) of diffractive dissociation of 190 GeV /c π- into π-π+π- final states on nuclear targets. A PWA of the data sample taken during a COMPASS pilot run in 2004 on a Pb target showed a significant spin-exotic JPC = 1-+ resonance consistent with the controversial π1(1600), which is considered to be a candidate for a non-[Formula: see text] mesonic state. In 2008 COMPASS collected a large diffractive π-π+π- data sample using a hydrogen target. A first comparison with the 2004 data shows a strong target dependence of the production strength of states with spin projections M = 0 and 1.
ONCE SUBTRACTED DISPERSION RELATIONS IN DESCRIPTION OF THE ππ D- AND F-WAVE AMPLITUDES
Authors: KAMIŃSKI ROBERT
Published: February 2011

Once subtracted dispersion relations with imposed crossing symmetry condition are applied in description of the ππ D- and F-wave amplitudes. We show that these equations impose strong constraints on experimental data and model amplitudes.
DETERMINATION OF THE STRONG COUPLING CONSTANT FROM NLO QCD ANALYSIS OF PROTON STRUCTURE FUNCTION
Authors: KHANPOUR H. , KHORRAMIAN ALI N. , TEHRANI S. ATASHBAR
Published: February 2011

In this article we present a determination of the strong coupling constant and parton distribution functions (PDFs) based on a next-to-leading order (NLO) perturbative QCD analysis of proton structure function. More precisely, we extract [Formula: see text] and PDFs by fitting perturbative QCD predictions to the data from the measurements of the proton structure function [Formula: see text] in deep inelastic scattering, which are based on perturbative QCD calculations up to NLO. We obtain at NLO [Formula: see text] in the variable-flavor number scheme.
Λ-HYPERNUCLEAR PRODUCTION IN $(K_{{\rm{stop}}}^-, \pi)$ REACTIONS
Authors: KREJČIŘÍK VOJTĔCH , CIEPLY ALEŠ
Published: February 2011

In the present contribution, we report on calculation of the Λ-hypernuclear production induced by the stopped kaon K-. We performed the calculation within the framework of the distorted wave impulse approximation and used chirally motivated transition amplitudes for the microscopic description of the elementary kaon-nucleon process. The sensitivity of the model to several effects was tested with a special attention paid to the impact caused by variations of the initial kaon and final state pion wave functions. The calculated production rates are reported for target nuclei from Lithium to Oxygen.
MESON PRODUCTION IN AN EFFECTIVE RELATIVISTIC MEAN FIELD MODEL
Authors: IAZZI F. , LAVAGNO A. , SZYMAńSKA K.
Published: February 2011

We study the meson yield ratios for high energy central nucleus-nucleus collisions by means of an effective relativistic mean-field model with the inclusion of the full octet of baryons, the Δ-isobars degrees of freedom and the lightest pseudoscalar and vector mesons. These last particles are considered in the so-called one-body contribution, taking into account of an effective chemical potential depending on the self-consistent interaction between baryons. The analysis is performed by requiring the global conservation of baryon number, electric charge fraction and zero net strangeness.
D* MESON PRODUCTION AND $F_2^{c\bar c}$ IN DIS AT HERA
Authors: ŁUSZCZAK AGNIESZKA
Published: February 2011

I calculate [Formula: see text] within two dipole models: GBW and CGC. I compare predictions with the last data from HERA. In the GBW and CGC saturation model the heavy quark contribution to F2 was considered in the form of the [Formula: see text] pair production. I calculate inclusive charm production in terms of [Formula: see text] and diffractive charm production in terms of [Formula: see text]. I find good agreement with data both in diffractive and inclusive case. [Formula: see text], measured by HERA, is an important issue in the determination of parton distribution functions (PDFs). Last measurement from H 16 shows that [Formula: see text] is consistent with D* data.
η MESON PRODUCTION IN PROTON-PROTON COLLISIONS AT 40 AND 72 MeV EXCESS ENERGY
Authors:   FOR THE CELSIUS/WASA COLLABORATION, PETRÉN HENRIK
Published: February 2011

Differential cross sections for η production in proton-proton collisions at 40 and 72 MeV above threshold show that higher partial waves are necessary to describe the reaction. A simple model assuming constant production amplitudes and including most partial waves up to two units of angular momentum reproduces the data rather well, and also describes the invariant mass distributions found at 15.5 MeV excess energy.
PERSPECTIVES OF THE NON-MESONIC WEAK DECAY IN DOUBLE HYPERNUCLEI
Authors: IAZZI F. , SZYMAŃSKA K. , LAVAGNO A. , YOUNIS H.
Published: February 2011

The features of the Hyperon Induced Non Mesonic Weak Decay in double hypernuclei are shortly reviewed and a preliminary evaluation of the expected production rate in the future PANDA experiment at FAIR is reported.
THE ABC EFFECT AND ITS ENERGY DEPENDENCE IN THE DOUBLE-PIONIC FUSION TO 4He
Authors:   FOR THE WASA-at-COSY COLLABORATION, PRICKING A. , CLEMENT H.
Published: February 2011

The double-pionic fusion reactions dd → 4 He π0π0 and dd → 4 He π+π- were measured exclusively and kinematically complete with the WASA detector at COSY. The measurements were performed in the energy range Tp = 0.8 - 1.4 GeV covering thus the full energy region, where the so-called ABC effect – a peculiar low-mass enhancement in the ππ-invariant mass spectrum – was observed previously in inclusive measurements. Our findings for the double-pionic fusion to 4 He are in accordance with the observations for the basic pn → dπ0π0 reaction pointing to the same fundamental mechanism. In both cases we observe that the ABC effect is associated with a peak in the energy dependence of the total cross section. In the 4 He case the peak structure in the total cross section is broadened in comparison to the deuteron case. This is consistent with both Fermi motion of the basic pn system within 4 He and with collision broadening as it is known, e.g., from excitations of the Δ resonance in nuclei.
ANALYSIS OF η → π+π-γ MEASURED WITH THE WASA FACILITY AT COSY
Authors:   FOR THE WASA-at-COSY COLLABORATION, REDMER CHRISTOPH F.
Published: February 2011

The decay η → π+π-γ has been measured with the WASA facility at COSY. The largest data set taken so far in an exclusive measurement was acquired, with 13740±140 events after background subtraction. Efficiency corrected Dalitz plot distributions have been extracted, which show the importance of final state interactions for the understanding of the decay.
THE STATUS OF MESONIC EXOTICA
Authors: WEYGAND DENNIS P.
Published: February 2011

Over twenty years ago QCD-inspired models of hadronic states began a rigorous search for meson outside of Naive Quark Model. Here we briefly review the current status of Exotica.
PION PRODUCTION MEASUREMENT IN NA61/SHINE EXPERIMENT
Authors:   ON BEHALF OF THE NA61/SHINE COLLABORATION, PALCZEWSKI TOMASZ JAN
Published: February 2011

This paper presents one of the physics goals of the NA61/SHINE experiment: measurements of hadron production needed for neutrino (T2K) and cosmic-ray (Pierre Auger and KASKADE) experiments. Preliminary results from the proton-Carbon interactions at 31 GeV/c for the T2K experiment at J-PARC are presented. Knowledge of pion and kaon production is important for improving the accuracy of neutrino flux simulations. Three different methods of the pion spectra extractions are presented. Finally, preliminary differential cross section dsigma/ dp in several intervals of emission angles of charged pion in p + C interactions at 31 GeV/c.
WIDEBAND OPERATION OF 2D PHOTONIC CRYSTAL DIRECTIONAL COUPLER WITH TOPOLOGY OPTIMIZED WAVEGUIDE BENDS
Authors: WATANABE YOSHINORI , IKEDA NAOKI , TAKATA YOSHIAKI , KITAGAWA YOSHINORI , OZAKI NOBUHIKO , SUGIMOTO YOSHIMASA , ASAKAWA KIYOSHI
Published: February 2011

A directional coupler in a two-dimensional photonic crystal slab waveguide was optimized to operate in wideband by applying topology optimized bends at input/output ports. We fabricated the sample based on the optimized design and demonstrated that the directional coupler performs properly in the transmittance and the bandwidth comparable to the straight waveguide. We experimentally confirmed the excellent extinction ratio (12 ~ 15dB) of bar and cross port.
SERS-ACTIVE SILVER NANOPARTICLES IN ION-EXCHANGED GLASS
Authors: CHEN YA , JAAKOLA JANNE , SÄYNÄTJOKI ANTTI , TERVONEN ARI , HONKANEN SEPPO
Published: February 2011

We study synthesis and SERS activity of glass-embedded ion-exchanged silver nanoparticles formed by two different methods. Silver-sodium ion-exchange process with heat treatment was utilized on commercial microscope slides, while masked ion-exchange technique was performed on glass Corning 0211. The distribution of particles was studied by absorption spectroscopy and atomic force microscopy. After etching the glass surface to expose the particles, SERS performance of these particles was investigated with micro-Raman spectroscopy using Rhodamine 6G as the analyte.
SURFACE PLASMON ENHANCED PHOTOLUMINESCENCE ON BIHARMONIC GRATING STRUCTURE
Authors: FUJIWARA YASUMASA , MURATA KOJI , OJIMA MASAYOSHI , OGAWA YASUHIRO , KUBO HITOSHI , YOSHIDA HIROYUKI , FUJII AKIHIKO , OZAKI MASANORI
Published: February 2011

We compare the fluorescence enhancement from a conducting polymer film placed on top of a sinusoidal and biharmonic metallic grating. On the biharmonic grating, which possesses a surface plasmon polariton band-gap, the enhancement factor was larger than that on a sinusoidal grating, even though the coupling efficiency of the surface plasmon polariton was lower for the biharmonic grating. We investigate the mechanism of fluorescence enhancement numerically by finite difference time domain analyses and attribute the larger fluorescence enhancement to the electric field of the short wavelength band-edge mode extending longer into the dielectric region where the fluorophore is placed.
COLOR TUNABLE ELECTROLUMINESCENCE FROM ORGANIC LIGHT-EMITTING DEVICES BY MANIPULATING EXCITON AND EXCIPLEX EMISSIONS
Authors: LAI SHIU-LUN , CHAN MEI-YEE , TONG QING-XIAO , LO MING-FAI , NG TSZ-WAI , LEE CHUN-SING , LEE SHUIT-TONG
Published: February 2011

While exciplex formation is considered to have a negative impact on the performance of organic light-emitting devices (OLEDs), it can be utilized as a simple means for manipulating the emission colors. Here, we explore various important factors influencing the exciplex formation in order to provide a simple way for tailoring the emission color of OLEDs involving exciplex emission. In addition to the well-known effects of the energy difference between electron affinity and ionization potential (IP) of organic materials used, we found that electron mobility and IP of electron-transporting layer (ETL) are also critical factors in controlling the intensity of exciplex emission via the influence on charge accumulation intensity at the organic/organic interface. Interestingly, devices with green, blue, and white electroluminescence colors can be attained by simply replacing different ETL materials in contact with the same blue fluorophore underneath. The underlying mechanism for the color change in OLEDs will be discussed.
INVESTIGATION OF TRAPPED LIGHT IN THIN-FILM SILICON SOLAR CELLS
Authors: BECKERS T. , BITTKAU K. , CARIUS R.
Published: February 2011

In thin-film silicon solar cell devices randomly textured interfaces are used to achieve light scattering sufficient for efficient light trapping. We use near-field scanning optical microscopy (NSOM) for visualizing wave guiding mechanisms experimentally by measuring the evanescent modes. Their impact on the light trapping efficiency and the link to topographic structures will be addressed.
RUTILE-ANATASE TiO2 PHOTOANODES FOR DYE-SENSITIZED SOLAR CELLS
Authors: PENG WENQIN , YANAGIDA MASATOSHI , HAN LIYUAN
Published: February 2011

Nanocrystalline rutile-anatase mixing phase TiO2 film was synthesized for dye-sensitized solar cells (DSCs). The mixing-phase nanocrystals, composed of 52 wt% rutile and 48 wt% anatase, contained nanorods with diameter of 20 nm and the length of more than 200 nm ascribed to rutile phase. The short circuit photocurrent of DSCs based on the rutile-anatase TiO2 nanocrystals was enhanced in comparison with that of DSCs based on anatase TiO2 because the light was effectively scattered by rutile nanorods in the mixing-phase TiO2 films.
FABRICATION OF A GaAs/AlGaAs LATTICE-MATCHED QUANTUM DOT SOLAR CELL
Authors: NODA T. , MANO T. , ELBORG M. , MITSUISHI K. , SAKODA K.
Published: February 2011

We report on the fabrication of a lattice-matched GaAs/AlGaAs quantum dot solar cell (QDSC) in which a ten-stacked QD layer is embedded. The GaAs QDs were grown by droplet epitaxy. Photocurrent originating from the QDs was confirmed. Cross-sectional scanning transmission electron microscopy (TEM) revealed no apparent dislocation in the QD layers.
LASER LIGHT CONTROL OF SELF-ORGANIZATION PROCESS
Authors: MATSUMURA YUKIMASA , INAMI WATARU , KAWATA YOSHIMASA
Published: February 2011

We present a controlling technique of microporous structure by laser irradiation during self-organization process. Polymer solution was dropped on the substrate at high humid condition and the honeycomb structure of regularly aligned pores on the film was fabricated by attaching of water droplets on the solution surface. We demonstrated that it was possible to prevent forming of pores at the region of laser irradiation and flat surface was fabricated. The method of our study is microfabrication processing technique that combines the advantages of bottom up and top down techniques. This method is expected that it is applied to photonic crystals, biological cell culturing, surface science and electronics fields.
INVESTIGATION OF HOMOLOGOUS SERIES AS PRECURSORY HYDROCARBONS FOR ALIGNED CARBON NANOTUBE FORMATION BY THE SPRAY PYROLYSIS METHOD
Authors: YANG ZHI , NIE HUAGUI , ZHOU XUEMEI , YAO ZHEN , HUANG SHAOMING , CHEN XIAOHUA
Published: February 2011

The precursory carbon source is one of the key parameters which govern the formation of carbon nanotubes (CNTs). In this work, by selecting four homologous series, namely n-pentane, n-hexane, n-heptane and n-octane, as investigated targets, we comparatively study the relationship between thermodynamic properties of the precursory carbon source and formation of aligned CNTs. We find that all of these alkanes are favored for the growth of aligned CNTs in a suitable growth environment. But only n-heptane can yield the aligned CNTs with relatively high quality, high yield and narrow diameter distribution. Furthermore, after considering the link between thermodynamic properties of the precursory carbon source and the morphology characteristic of the nanotube samples, we find that the Gibbs free energy and formation enthalpy of precursory carbon sources play critical roles in the nanotube formation. In additions some possible explanations are proposed to better understand these phenomena. These rules will be very helpful in making clearer the formation mechanism from the precursory carbon sources to the CNTs, and preparing large-scale aligned CNTs with diameter control at low cost.
PHASE DIFFERENCE BETWEEN LOW-FREQUENCY OSCILLATIONS OF CEREBRAL DEOXY- AND OXY-HEMOGLOBIN CONCENTRATIONS DURING A MENTAL TASK
Authors: SASSAROLI ANGELO , ZHENG FENG , PIERRO MICHELE , BERGETHON PETER R. , FANTINI SERGIO
Published: February 2011

Hemodynamic low-frequency (~0.1 Hz) spontaneous oscillations as detected in the brain by near-infrared spectroscopy have potential applications in the study of brain activation, cerebral autoregulation, and functional connectivity. In this work, we have investigated the phase lag between oscillations of cerebral deoxy- and oxy-hemoglobin concentrations in the frequency range 0.05–0.10 Hz in a human subject during a mental workload task. We have obtained a measure of such phase lag using two different methods: (1) phase synchronization analysis as used in the theory of chaotic oscillators and (2) a novel cross-correlation phasor approach. The two methods yielded comparable initial results of a larger phase lag between low-frequency oscillations of deoxy- and oxy-hemoglobin concentrations during mental workload with respect to a control, rest condition.
REAL-TIME FLUORESCENCE IMAGING OF SIRT1 CYTOSOLIC TRANSLOCATION UNDER THE TREATMENT OF GROWTH FACTOR DEPRIVATION
Authors: MENG CHENGBO , WU SHENGNAN , XING DA
Published: February 2011

Sirtuins comprise a family of enzymes implicated in the determination of organismal lifespan in yeast and the nematode. Human sirtuin SIRT1 has been shown to deacetylate several proteins in a NAD+-dependent manner. It is reported that SIRT1 regulates physiological processes including senescence, fat metabolism, glucose homeostasis, apoptosis, and neurodegeneration. In general, SIRT1 has initially been thought to represent an exclusive nuclear protein. However, depending on the cell lines and organisms examined, a partial or temporary cytoplasmic localization was observed in murine pancreatic beta cells and neonatal rat cardiomyocytes. Since SIRT1 deacetylates both histone and nonhistone-proteins, such as a number of transcription factors, changes in subcellular localization probably play a role in the regulation of its function. In the present studies, we investigated the subcellular localization of SIRT1 in response to growth factor deprivation in African green monkey SV40-transformed kidney fibroblast cells (COS-7). Using SIRT1-EGFP fluorescence reporter, we found that SIRT1 localized to nucleus in physiological conditions. We devised a model enabling cell senescence via growth factor deprivation and found that SIRT1 partially translocated to cytosol under the treatment, suggesting a reduced level of SIRT1 activity. We found PI3K/Akt pathway was involved in the inhibition of SIRT1's cytosolic translocation, because inhibition of these kinases significantly decreased the amount of SIRT1 maintained in nucleus. Taken together, we demonstrate that growth factor deprivation induces cytosolic translocation of SIRT1, which suggests a possible connection between cytoplasm-localized SIRT1 and the aging process and provides a new application of single molecule fluorescence imaging of the molecule events in living cells.
Raloxifene attenuates Gas6 and apoptosis in experimental aortic valve disease in renal failure
Authors: Shuvy Mony , Abedat Suzan , Beeri Ronen , Valitsky Michael , Daher Sameh , Kott-Gutkowski Miriam , Gal-Moscovici Anca , Sosna Jacob , Rajamannan Nalini M. , Lotan Chaim
Published: February 2011

Renal failure is associated with aortic valve calcification. Using our rat model of uremia-induced reversible aortic valve calcification, we assessed the role of apoptosis and survival pathways in that disease. We also explored the effects of raloxifene, an estrogen receptor modulator, on valvular calcification. Gene array analysis was performed in aortic valves obtained from three groups of rats ( n = 7 rats/group): calcified valves obtained from rats fed with uremic diet, valves after calcification resolution following diet cessation, and control. In addition, four groups of rats ( n = 10 rats/group) were used to evaluate the effect of raloxifene in aortic valve calcification: three groups as mentioned above and a fourth group fed with the uremic diet that also received daily raloxifene. Evaluation included imaging, histology, and antigen expression analysis. Gene array results showed that the majority of the altered expressed genes were in diet group valves. Most apoptosis-related genes were changed in a proapoptotic direction in calcified valves. Apoptosis and decreases in several survival pathways were confirmed in calcified valves. Resolution of aortic valve calcification was accompanied by decreased apoptosis and upregulation of survival pathways. Imaging and histology demonstrated that raloxifene significantly decreased aortic valve calcification. In conclusion, downregulation of several survival pathways and apoptosis are involved in the pathogenesis of aortic valve calcification. The beneficial effect of raloxifene in valve calcification is related to apoptosis modulation. This novel observation is important for developing remedies for aortic valve calcification in patients with renal failure.
Angiotensin type I receptor blockade in conjunction with enhanced Akt activation restores coronary collateral growth in the metabolic syndrome
Authors: Jadhav Rashmi , Dodd Tracy , Smith Erika , Bailey Erin , DeLucia Angelo L. , Russell James C. , Madison Rowan , Potter Barry , Walsh Kenneth , Jo Hanjoong , Rocic Petra
Published: February 2011

We have previously demonstrated that Akt was required for repetitive ischemia (RI)-induced coronary collateral growth (CCG) in healthy rats but was not activated by RI in the metabolic syndrome (JCR:LA-cp rats) where CCG was impaired. Here we hypothesized that failure of angiotensin type I receptor (AT1R) blockers to restore Akt activation is a key determinant of their inability to completely restore CCG in the metabolic syndrome. Therefore, we investigated whether adenovirus-mediated delivery of constitutively active Akt (MyrAkt-Adv) in conjunction with AT1R blockade (candesartan) was able to restore RI-induced CCG in JCR:LA-cp rats. Successful myocardial MyrAkt-Adv delivery was confirmed by a >80% transduction efficiency and an approximately fourfold increase in Akt expression and activation. CCG was assessed by myocardial blood flow measurements in the normal and collateral-dependent zones. MyrAkt-Adv alone significantly increased RI-induced CCG in JCR:LA-cp rats (∼30%), but it completely restored CCG in conjunction with administration of candesartan. In contrast, dominant negative Akt (DN-Akt-Adv) reversed the beneficial effect of candesartan on CCG in JCR:LA-cp rats. We conclude that optimal restoration of coronary collateral growth in JCR:LA-cp rats requires a combination of AT1R blockade with constitutive Akt activation. These findings may carry implications for metabolic syndrome patients in need of coronary revascularization.
Single motor unit recordings in human geniohyoid reveal minimal respiratory activity during quiet breathing
Authors: Brown Elizabeth C. , Hudson Anna L. , Butler Jane E. , McKenzie David K. , Bilston Lynne E. , Gandevia Simon C.
Published: February 2011

Maintenance of airway patency during breathing involves complex interactions between pharyngeal dilator muscles. The few previous studies of geniohyoid activity using multiunit electromyography (EMG) have suggested that geniohyoid shows predominantly inspiratory phasic activity. This study aimed to quantify geniohyoid respiration-related activity with single motor unit (SMU) EMG recordings. Six healthy subjects of normal body mass index were studied. Intramuscular EMG recordings of geniohyoid activity were made with a monopolar needle with subjects in supine and seated positions. The depth of the geniohyoid was identified by ultrasound, and the electrode position was confirmed with maneuvers to isolate activity in geniohyoid and genioglossus. Activity was recorded at 85 sites in the geniohyoid during quiet breathing (45 supine and 40 seated). When subjects were supine, 33 sites (73%) showed no activity during breathing and 10 (22%) showed tonic activity. In addition, one site showed a tonic SMU with increased expiratory discharge, and one site in another subject had one unit with expiratory phasic activity. When subjects were seated, 27 sites (68%) in the geniohyoid showed no activity, 12 sites (30%) showed tonic activity that was not respiration related, and one unit at one site showed phasic expiratory activity. The average peak discharge frequency of geniohyoid motor units was 16.2 ± 3.1 impulses/s during the “geniohyoid maneuver,” which was the first part of a swallow. In contrast to previous findings, the geniohyoid shows some tonic activity but minimal respiration-related activity in healthy subjects in quiet breathing. The geniohyoid has little active role in airway stability under these conditions.
Aerosol deposition characteristics in distal acinar airways under cyclic breathing conditions
Authors: Ma Baoshun , Darquenne Chantal
Published: February 2011

Although the major mechanisms of aerosol deposition in the lung are known, detailed quantitative data in anatomically realistic models are still lacking, especially in the acinar airways. In this study, an algorithm was developed to build multigenerational three-dimensional models of alveolated airways with arbitrary bifurcation angles and spherical alveolar shape. Using computational fluid dynamics, the deposition of 1- and 3-μm aerosol particles was predicted in models of human alveolar sac and terminal acinar bifurcation under rhythmic wall motion for two breathing conditions (functional residual capacity = 3 liter, tidal volume = 0.5 and 0.9 liter, breathing period = 4 s). Particles entering the model during one inspiration period were tracked for multiple breathing cycles until all particles deposited or escaped from the model. Flow recirculation inside alveoli occurred only during transition between inspiration and expiration and accounted for no more than 1% of the whole cycle. Weak flow irreversibility and convective transport were observed in both models. The average deposition efficiency was similar for both breathing conditions and for both models. Under normal gravity, total deposition was ∼33 and 75%, of which ∼67 and 96% occurred during the first cycle, for 1- and 3-μm particles, respectively. Under zero gravity, total deposition was ∼2–5% for both particle sizes. These results support previous findings that gravitational sedimentation is the dominant deposition mechanism for micrometer-sized aerosols in acinar airways. The results also showed that moving walls and multiple breathing cycles are needed for accurate estimation of aerosol deposition in acinar airways.
Quantitative analysis of the postcontractile blood-oxygenation-level-dependent (BOLD) effect in skeletal muscle
Authors: Towse Theodore F. , Slade Jill M. , Ambrose Jeffrey A. , DeLano Mark C. , Meyer Ronald A.
Published: February 2011

Previous studies show that transient increases in both blood flow and magnetic resonance image signal intensity (SI) occur in human muscle after brief, single contractions, and that the SI increases are threefold larger in physically active compared with sedentary subjects. This study examined the relationship between these transient changes by measuring anterior tibial artery flow (Doppler ultrasound), anterior muscle SI (3T, one-shot echo-planar images, TR/TE = 1,000/35), and muscle blood volume and hemoglobin saturation [near-infrared spectroscopy (NIRS)] in the same subjects after 1-s-duration maximum isometric ankle dorsiflexion contractions. Arterial flow increased to a peak 5.9 ± 0.7-fold above rest (SE, n = 11, range 2.6–10.2) within 7 s and muscle SI increased to a peak 2.7 ± 0.6% (range 0.0–6.0%) above rest within 12 s after the contractions. The peak postcontractile SI change was significantly correlated with both peak postcontractile flow ( r = 0.61, n = 11) and with subject activity level ( r = 0.63, n = 10) estimated from 7-day accelerometer recordings. In a subset of 7 subjects in which NIRS data acquisition was successful, the peak magnitude of the postcontractile SI change agreed well with SI calculated from the NIRS blood volume and saturation changes ( r = 0.80, slope = 1.02, intercept = 0.16), confirming the blood-oxygenation-level-dependent (BOLD) mechanism underlying the SI change. The magnitudes of postcontractile changes in blood saturation and SI were reproduced by a simple one-compartment muscle vascular model that incorporated the observed pattern of postcontractile flow, and which assumed muscle O2 consumption peaks within 2 s after a brief contraction. The results show that muscle postcontractile BOLD SI changes depend critically on the balance between O2 delivery and O2 consumption, both of which can be altered by chronic physical activity.
Diverse patterns of myocardial fibrosis in lifelong, veteran endurance athletes
Authors: Wilson M. , O'Hanlon R. , Prasad S. , Deighan A. , MacMillan P. , Oxborough D. , Godfrey R. , Smith G. , Maceira A. , Sharma S. , George K. , Whyte G.
Published: February 2011

This study examined the cardiac structure and function of a unique cohort of documented lifelong, competitive endurance veteran athletes (>50 yr). Twelve lifelong veteran male endurance athletes [mean ± SD (range) age: 56 ± 6 yr (50–67)], 20 age-matched veteran controls [60 ± 5 yr; (52–69)], and 17 younger male endurance athletes [31 ± 5 yr (26–40)] without significant comorbidities underwent cardiac magnetic resonance (CMR) imaging to assess cardiac morphology and function, as well as CMR imaging with late gadolinium enhancement (LGE) to assess myocardial fibrosis. Lifelong veteran athletes had smaller left (LV) and right ventricular (RV) end-diastolic and end-systolic volumes ( P < 0.05), but maintained LV and RV systolic function compared with young athletes. However, veteran athletes had a significantly larger absolute and indexed LV and RV end-diastolic and systolic volumes, intraventricular septum thickness during diastole, posterior wall thickness during diastole, and LV and RV stroke volumes ( P < 0.05), together with significantly reduced LV and RV ejection fractions ( P < 0.05), compared with veteran controls. In six (50%) of the veteran athletes, LGE of CMR indicated the presence of myocardial fibrosis (4 veteran athletes with LGE of nonspecific cause, 1 probable previous myocarditis, and 1 probable previous silent myocardial infarction). There was no LGE in the age-matched veteran controls or young athletes. The prevalence of LGE in veteran athletes was not associated with age, height, weight, or body surface area ( P > 0.05), but was significantly associated with the number of years spent training ( P < 0.001), number of competitive marathons ( P < 0.001), and ultraendurance (>50 miles) marathons ( P < 0.007) completed. An unexpectedly high prevalence of myocardial fibrosis (50%) was observed in healthy, asymptomatic, lifelong veteran male athletes, compared with zero cases in age-matched veteran controls and young athletes. These data suggest a link between lifelong endurance exercise and myocardial fibrosis that requires further investigation.
Experimentally tested computer modeling of stress fractures in rats
Authors: Stern-Perry Michal , Gefen Amit , Shabshin Nogah , Epstein Yoram
Published: February 2011

The objective of this study was to develop a finite-element (FE) modeling methodology for studying the etiology of a stress fracture (SF). Several variants of three-dimensional FE models of a rat hindlimb, which differed in length or stiffness of tissues, enabling the analyses of mechanical strains and stress in the tibia, were created. We compared the occurrence of SFs in an animal model to validate locations of peak strains/stresses in the FE models. Four Sprague-Dawley male rats, age ∼7 wk, were subjected to mechanical cyclic loads of 1.2 Hz and ∼6 N, which were delivered to their hindlimb for 30 min, 3 times/wk, up to 12 wk, by using a specially designed apparatus. The results showed that 1) FE modeling predicted the maximal strains/stresses (∼220,0 με and ∼29 MPa, respectively) between the mid- and proximal thirds of the tibia; 2) in a longer shin, greater and more inhomogeneous tensile strains/stresses were evident, at the same location; 3) anatomical variants in shin length influenced the strain/stress distributions to a greater extent with respect to changes in mechanical properties of tissues; and 4) bone stiffness was more dominant than muscle stiffness in affecting the strain/stress distributions. In the animal study, 35,000 loading cycles were associated with the formation of a SF. The location of the identified SF in the rat limb verified the FE model. We find the suggested model a valuable tool in studying various aspects of SFs.
MicroRNA-205 Inhibits Src-Mediated Oncogenic Pathways in Renal Cancer
Authors: Majid Shahana , Saini Sharanjot , Dar Altaf A. , Hirata Hiroshi , Shahryari Varahram , Tanaka Yuichiro , Yamamura Soichiro , Ueno Koji , Zaman Mohd Saif , Singh Kamaldeep , Chang Inik , Deng Guoren , Dahiya Rajvir
Published: February 2011

The Src family of protein kinases (SFK) plays key roles in regulating fundamental cellular processes, including cell growth, differentiation, cell shape, migration, and survival, and specialized cell signals in various malignancies. The pleiotropic functions of SFKs in cancer make them promising targets for intervention. Here, we sought to investigate the role of microRNA-205 (miR-205) in inhibition of Src-mediated oncogenic pathways in renal cancer. We report that expression of miR-205 was significantly suppressed in renal cancer cell lines and tumors when compared with normal tissues and a nonmalignant cell line and is correlated inversely with the expression of SFKs. miR-205 significantly suppressed the luciferase activity of reporter plasmids containing the 3′-UTR (untranslated region) sequences complementary to either Src, Lyn, or Yes, which was abolished by mutations in these 3′-UTR regions. Overexpression of miR-205 in A498 cells reduced Src, Lyn, and Yes expression, both at mRNA and protein levels. Proliferation of renal cancer cells was suppressed by miR-205, mediated by the phospho-Src–regulated ERK1/2 pathway. Cell motility factor FAK (focal adhesion kinase) and STAT3 activation were also inhibited by miR-205. Transient and stable overexpression of miR-205 in A498 cells resulted in induction of G0/G1 cell-cycle arrest and apoptosis, as indicated by decreased levels of cyclin D1 and c-Myc, suppressed cell proliferation, colony formation, migration, and invasion in renal cancer cells. miR-205 also inhibited tumor cell growth in vivo. This is the first study showing that miR-205 inhibits proto-oncogenic SFKs, indicating a therapeutic potential of miR-205 in the treatment of renal cancer. Cancer Res; 71(7); 2611–21. ©2011 AACR.
Frequency Alterations in Key Innate Immune Cell Components in the Peripheral Blood of Dengue Patients Detected by FACS Analysis
Authors: Tsai Jih-Jin , Jen Yen-Hua , Chang Jung-San , Hsiao Hui-Mien , Noisakran Sansanee , Perng Guey Chuen
Published: February 2011

Dengue is a timing disease, and frequently dengue patients do not seek help until 2–3 days after prodrome. Thus, the innate immune parameters in dengue patients remain largely unexplored. A comprehensive FACS profiling of key innate immune cells in the peripheral blood of dengue patients was performed. Twenty-seven dengue patients varying in days of fever onset were enrolled and the majority of them had primary infection based on serological results. FACS panels were used to evaluate NK cells, platelet-leukocyte aggregates (PLA), inflammatory monocytes, and plasmacytoid (pDC) and myeloid dendritic cells (mDC). FACS results showed the following findings: (i) NK cells significantly dropped on day 5 after the onset of fever and gradually returned to normal within 2 weeks of illness; (ii) biphasic PLA were observed, maximum levels were reached on days 6–8 and 11–16, and platelet-monocyte aggregates (PMA) were the most frequent event; (iii) inflammatory monocytes were consistently lower on days 5–8 and gradually returned to the normal level in the second week of illness, and (iv) pDC reached the maximum level on day 5 and gradually declined to the baseline level after 1 week of illness. In contrast, mDC fluctuated somewhat during the first week of illness and returned to the baseline level in the second week of illness. The most interesting finding was the biphasic PLA, in particular the PMA. These innate immunological parameters could be a crucial factor dictating the complicated pathogenesis of dengue disease.
Small-Scale Cannabis Growers in Denmark and Finland
Authors: Hakkarainen Pekka , Frank Vibeke Asmussen , Perälä Jussi , Dahl Helle Vibeke
Published: February 2011

Aims: To compare domestic cannabis cultivation in Denmark and Finland to describe national characteristics in small-scale cannabis growing. Design: A Web survey conducted among small-scale cannabis growers in Denmark (June to November 2008) and Finland (May to June 2009). Participants: Current cannabis growers (Denmark, 401; Finland, 1,054). Measurements: Comparisons in regard to social background, growing history, practices, purposes and motives of growing, and perceptions of risks. Findings: Cannabis was cultivated primarily for own use, but sharing with friends and avoiding criminal circles also were significant motives for growing. Finnish growers prioritized indoor cultivation, whereas the Danes were more in favor of open-air plantations. Risks of getting caught by the police were observed to be greater in Finland. Growing for medical purposes was twice as prevalent in Finland as in Denmark. Conclusions: Cannabis growing is a stronger and more novel phenomenon in Finland than in Denmark, but both countries have been influenced by international trends. Finnish and Danish small-scale cannabis cultivators can be considered to be ideologically oriented lifestyle growers. Differences in the magnitude of the phenomenon may reflect differences in the availability and quality of cannabis in national drug markets. The Internet had promoted the spreading of the trend.