bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Autonomic Nerve Preservation and Lateral Node Dissection on Male Urogenital Function after Total Mesorectal Excision for Lower Rectal Cancer
Authors: Kyo Kennoki , Sameshima Shinichi , Takahashi Minoru , Furugori Taiki , Sawada Toshio
Published: May 2006

Introduction

Urogenital dysfunction is a well recognized complication of rectal cancer surgery. The aim of this study was to assess the impact of autonomic nerve preservation (ANP) and lateral node dissection (LND) on male urogenital function after total mesorectal excision for lower rectal cancer.

Methods

We studied, using a questionnaire, preoperative and current urogenital function in 47 male patients who underwent total mesorectal excision with the ANP technique for lower rectal cancer. Patients with and without LND were analyzed separately.

Results

A total of 37 patients (78.7%) (22 patients without LND, 15 with LND) returned the questionnaire. Among the 15 patients with LND, 2 underwent unilateral ANP. One patient without LND had urinary dysfunction preoperatively, and among the other 21 patients only 2 (9.5%) reported minor urinary complications postoperatively. After LND, 5 patients (33%) reported minor complications; there were no severe complications. Among patients who were sexually active prior to the operation, 90% and 70% of patients without LND and 50% and 10% of those with LND maintained sexual activity and ejaculation, respectively. However, 50% of patients who underwent low anterior resection or Hartmann resection without LND and all patients with abdominoperineal resection or LND reported reduced overall sexual satisfaction.

Conclusions

The ANP technique offers the great advantage of maintaining urogenital function after rectal cancer surgery. After LND, although the ANP technique minimized urinary dysfunction, sexual function, particularly ejaculation, was often damaged. Careful follow‐up is important even after ANP to improve postoperative sexual satisfaction.
Grain-scale deformation in the Palaeoproterozoic Dongargarh Supergroup, central India: implications for shallow crustal deformation mechanisms from microstructural analysis
Authors: GHOSH GAUTAM , CHAKRABORTY SUKANYA , MUKHOPADHYAY JOYDIP , RAY ARIJIT
Published: May 2006

Analysis of the grain-scale deformation mechanisms in folded rocks of the Dongargarh Supergroup, central India, reveals that deformation was accomplished by a combination of pressure solution, microfracturing and dislocation creep processes. The finite strain was assessed using the Rf/ϕ method (X/Z ≈ 2). Partitioning of strain into various deformation mechanisms revealed that dislocation creep and pressure solution were the major contributors to the finite strain, followed by microfracturing. Analyses of microstructures suggest a sequence of dislocation creep followed by pressure solution and microfracturing, that ultimately gave way to microfracturing and limited crystallization or recrystallization. Overall constancy in volume during deformation is suggested from the balance between fracture-related grain-scale dilatancy and solution-related volume loss. Observations on cleavage spacing within various lithologies in a specific structural setting suggest that lithology played a vital role in cleavage development. Cleavage development in sandstones of the Dongargarh Supergroup required thin shale interbeds (for competency contrast) and grain size <0.036 mm (4.75 ϕ).
Differentiating Pleistocene tectonically driven and climate-related fluvial incision: the Sanggan River, Datong Basin, North China
Authors: SHAO-PING CHENG , CHUAN-YOU LI , GUI-ZHI YANG , SHI-WEI ZHOU
Published: May 2006

The Sanggan River is an alluvial river flowing through a graben basin system of the northern Shanxi Rift Zone, North China. During Pleistocene times, the river reach in the Datong Basin was affected successively by various external variables, such as invasion by basaltic flow, along-valley faulting and climatic change. Therefore, it provides excellent constraints for differentiating tectonically driven and climate-related fluvial incision in the context of tectonic subsidence. Based on equilibrium profile analysis, K–Ar dating of basalts (0.74–0.41 Ma), studies of the river terrace and of stream action history, we present a conceptual model for differentiating fault-driven and climate-related fluvial incision by the river. The results show that fluvial incision induced by tectonic lowering of the base-level due to along-valley movement on the Sanggan River fault is equal to fault displacement. The amount of post-basalt fluvial incision of the reach upstream from the lava dam is 23 to 25 m, of which the fault-driven and climate-related incisions are 15 m and 8 to 10 m, respectively, the former predominating over the latter. The total amount of incision in the lava dam reach is 40 to 47 m, of which the fault-driven and climate-related incisions are 10 m and 30–37 m, respectively; here the latter is predominant over the former. Since 0.41 ± 0.10 Ma, the rate of fluvial incision of the lava dam reach of the river has reached 98–115 m/Ma, which is 1.5–2 times as great as those of the reaches upstream and downstream from the lava dam. The higher rate of fluvial incision can be attributed to high water levels supplied by the onset and maintenance of backwater conditions in the reach upstream from the lava dam, due to the long period of warm and humid climate in this region. Plucking, abrasion and knickpoint migration appear to be the primary erosional processes in the lava dam reach.
Gravitational spreading controls rift zones and flank instability on El Hierro, Canary Islands
Authors: MÜNN SEBASTIAN , WALTER THOMAS R. , KLÜGEL ANDREAS
Published: May 2006

Ocean island volcanoes frequently develop local rift zones associated with flank movement and flank collapses. The ocean island El Hierro grew by coalescence and collapse of three volcanic edifices, which are an elongated topographic ridge (the Southern Ridge) and two semi-circular volcanic cones (Tiñor volcano, El Golfo volcano). During edifice growth and volcano coalescence, eruption fissures nucleated into rift zones that developed a complex triangle pattern. In scaled analogue experiments we could successfully reproduce the geometry of rift zones and unstable flanks as observed on El Hierro. The experimental results suggest that the rift configuration on El Hierro is the result of gravitational volcano spreading over deformable basal substrata, rather than of deep-seated magma updoming as thought previously. This paper elucidates the importance of the basal substratum and gravitational spreading, and the relationship to rifting and flank instability on El Hierro Island, and may help in understanding similar volcano architectures elsewhere.
Outbreaks of waterborne infectious intestinal disease in England and Wales, 1992–2003
Authors: SMITH A. , REACHER M. , SMERDON W. , ADAK G. K. , NICHOLS G. , CHALMERS R. M.
Published: May 2006

We reviewed the epidemiological and microbiological characteristics of 89 reported outbreaks of waterborne infectious intestinal disease affecting 4321 people in England and Wales over the period 1992–2003. Public water supplies were implicated in 24 outbreaks (27%), private water supplies in 25 (28%), swimming pools in 35 (39%) and other sources in five outbreaks (6%). Cryptosporidium was implicated in 69% of outbreaks, Campylobacter sp. in 14%, Giardia in 2%, E. coli O157 in 3% and Astrovirus in 1%. From 2000, there was a consistent decline in the number of outbreaks of waterborne disease associated with public water supplies. The incidence rate of outbreaks in recipients of private water supplies may be as high as 35 times the rate in those receiving public water supplies (1830 vs. 53 per million population). Private water suppliers need to be aware of the importance of adequate treatment and the prevention of faecal contamination of storage water. Swimming-pool operators need to ensure chlorination and in particular adequate filtration measures are in place.
Equivalence-checking on infinite-state systems: Techniques and results
Authors: KUČERA ANTONÍN , JANČAR PETR
Published: May 2006

The paper presents a selection of recently developed and/or used techniques for equivalence-checking on infinite-state systems, and an up-to-date overview of existing results (as of September 2004).
Demand for life annuities from married couples with a bequest motive
Authors: VIDAL-MELIÁ CARLOS , LEJÁRRAGA-GARCÍA ANA
Published: May 2006

The aim of this paper is to explain the ‘annuities puzzle’ in greater depth by introducing the bequest motive. It will try to determine whether this motive really is a relevant feature influencing the demand for life annuities from married couples. With this aim in mind, we develop an optimization model of the utility provided by purchasing a life annuity with contingent survivor benefit or a joint survivor life annuity. Our model is based on that first put forward by Brown and Poterba (2000), to which we have added elements from other models, such as Friedman and Warshawsky's (1990) and Vidal and Lejárraga's (2004), which include the bequest motive. This will enable us to calculate the annuity equivalent wealth and the optimal percentage of wealth to annuitize in various contexts: the possibility of access to actuarially fair annuity markets, the inclusion of so-called market imperfections, and the assumption that couples already have part of their wealth in pre-existing life annuities. Numerical results are presented for the case of Spain. The bequest motive is found not to be a significant factor influencing the demand for annuities from couples. Indeed very few couples would be willing to purchase them once we take into account the combined effects of market imperfections, the possibility of pre-existing annuities and the bequest motive. These findings have repercussions for policy makers regulating defined contribution capitalization systems, which are complementary to defined benefit systems.
Dorfin prevents cell death by reducing mitochondrial localizing mutant superoxide dismutase 1 in a neuronal cell model of familial amyotrophic lateral sclerosis
Authors: Takeuchi Hideyuki , Niwa Jun‐ichi , Hishikawa Nozomi , Ishigaki Shinsuke , Tanaka Fumiaki , Doyu Manabu , Sobue Gen
Published: May 2006

Dorfin is a RING‐finger type ubiquitin ligase for mutant superoxide dismutase 1 (SOD1) that enhances its degradation. Mutant SOD1s cause familial amyotrophic lateral sclerosis (FALS) through the gain of unelucidated toxic properties. We previously showed that the accumulation of mutant SOD1 in the mitochondria triggered the release of cytochrome c, followed by the activation of the caspase cascade and induction of neuronal cell death. In the present study, therefore, we investigated whether Dorfin can modulate the level of mutant SOD1 in the mitochondria and subsequent caspase activation. We showed that Dorfin significantly reduced the amount of mutant SOD1 in the mitochondria, the release of cytochrome c and the activation of the following caspase cascade, thereby preventing eventual neuronal cell death in a neuronal cell model of FALS. These results suggest that reducing the accumulation of mutant SOD1 in the mitochondria may be a new therapeutic strategy for mutant SOD1‐associated FALS, and that Dorfin may play a significant role in this.
Co‐expressed presenilin 1 NTF and CTF form functional γ‐secretase complexes in cells devoid of full‐length protein
Authors: Laudon Hanna , Mathews Paul M. , Karlström Helena , Bergman Anna , Farmery Mark R. , Nixon Ralph A. , Winblad Bengt , Gandy Samuel E. , Lendahl Urban , Lundkvist Johan , Näslund Jan
Published: May 2006

The enzyme γ‐secretase catalyzes the intramembrane proteolytic cleavage that generates the amyloid β‐peptide from the β‐amyloid precursor protein. The presenilin (PS) protein is one of the four integral membrane protein components of the mature γ‐secretase complex. The PS protein is itself subjected to endoproteolytic processing, generating stable N‐ and C‐terminal fragment (NTF and CTF, respectively) heterodimers. Here we demonstrate that coexpression of PS1 NTF and CTF functionally mimics expression of the full‐length PS1 protein and restores γ‐secretase activity in PS‐deficient mammalian cells. The coexpressed fragments re‐associate with each other inside the cell, where they also interact with nicastrin, another γ‐secretase complex component. Analysis of γ‐secretase activity following the expression of mutant forms of NTF and CTF, under conditions bypassing endoproteolysis, indicated that the putatively catalytic Asp257 and Asp385 residues have a direct effect on γ‐secretase activity. Moreover, we demonstrate that expression of the wild‐type CTF rescues endoproteolytic cleavage of C‐terminally truncated PS1 molecules that are otherwise uncleaved and inactive. Recovery of cleavage is critically dependent on the integrity of Asp385. Taken together, our findings indicate that ectopically expressed NTF and CTF restore functional γ‐secretase complexes and that the presence of full‐length PS1 is not a requirement for proper complex assembly.
Applications of stereoscopic particle image velocimetry: Dust acoustic waves and velocity space distribution functions
Authors: Thomas Edward , Williams Jeremiah
Published: May 2006

Two-dimensional particle image velocimetry (2D-PIV) techniques have been applied to dusty plasmas for the past 5 years. During that time, 2D-PIV has been used to provide detailed measurements of microparticle transport in dusty plasmas. However, a measurement of the third velocity vector direction is necessary to fully understand the microparticle transport. In this paper, stereoscopic particle image velocimetry (stereo-PIV) is used as a technique for obtaining all three-velocity vector components. This paper discusses the application of stereo-PIV techniques to measurements of dust acoustic waves and velocity space distribution functions in dusty plasmas.
Investigation of the dynamics of two coupled oscillators with mixed quantum-classical methods
Authors: Li Jingrui , Woywod Clemens , Vallet Valérie , Meier Christoph
Published: May 2006

The dynamics of two coupled oscillators can become quite complex if anharmonic potential energy functions are employed. This type of system therefore represents a good model for an investigation of the performance of mixed quantum-classical methods. In this work, the motion of two coupled particles with a mass ratio of one to ten is studied with three different mixed quantum-classical methods in the presence of anharmonic potential terms for a comparison with exact quantum mechanical calculations. The mixed quantum-classical approaches include the multitrajectory Ehrenfest, the mixed quantum-classical Bohmian (MQCB), and the so-called coupled Schrödinger equations (CSE) formalisms. The analysis shows that while the description of a weakly anharmonic system by the Ehrenfest and MQCB schemes is accurate if proper sampling techniques are applied, both approximations break down rapidly if the anharmonic terms are increased. The performance of the simple CSE prescription, which corresponds to a reduction of the full two-dimensional wave function to two one-dimensional wave functions representing two quantum oscillators coupled via the potential energy in a classical fashion, decreases if the width of the initial wave packet is enlarged. The dependence of the CSE method on the diffuseness of the initial wave packet is therefore opposite to that of the MQCB method, which is more accurate for wide wave packets. Overall, the multitrajectory Ehrenfest ansatz is found to be most successful in reproducing the exact quantum results.
Effect of self-gravitation on the energy loss of pair of projectiles in dusty plasma
Authors: Mirza Arshad M. , Sarwar M. Adnan , Qaisar M. S.
Published: May 2006

The effect of self-gravitation of massive dust grains is investigated on the shielded potential and the energy loss of pair of charged projectiles passing through a dust-contaminated plasma. Analytical general expressions are derived for the shielded potential and for the energy loss by incorporating two-body correlation effects. An interference contribution of these projectiles to the shielded potential and energy loss is observed that depends upon their orientation and separation distance. It is found that for two collinear projectiles the potential is enhanced by increasing dust Jeans frequency for separation less than Debye length and the energy loss versus projectile velocity decreases with the increase of Jeans frequency for arbitrary separation. The effect of inclination of two noncollinear projectiles on energy loss is also investigated for a fixed value of Jeans frequency ωjd=4×10−4ωpd. The contribution to the energy loss due to the interference term has been separately calculated for a typical Jeans frequency. The present investigation would be useful to explain the coagulation of dust particles in the molecular clouds and in the ion-beam-driven inertial confinement fusion approach.
Jacobi identity for vertex algebras in higher dimensions
Authors: Bakalov Bojko , Nikolov Nikolay M.
Published: May 2006

Vertex algebras in higher dimensions, introduced previously by Nikolov, provide an algebraic framework for investigating axiomatic quantum field theory with global conformal invariance. We develop further the theory of such vertex algebras by introducing formal calculus techniques and investigating the notion of polylocal fields. We derive a Jacobi identity which together with the vacuum axiom can be taken as an equivalent definition of vertex algebra.
Magnetohydrodynamics of fractal media
Authors: Tarasov Vasily E.
Published: May 2006

The fractal distribution of charged particles is considered. An example of this distribution is the charged particles that are distributed over the fractal. The fractional integrals are used to describe fractal distribution. These integrals are considered as approximations of integrals on fractals. Typical turbulent media could be of a fractal structure and the corresponding equations should be changed to include the fractal features of the media. The magnetohydrodynamics equations for fractal media are derived from the fractional generalization of integral Maxwell equations and integral hydrodynamics (balance) equations. Possible equilibrium states for these equations are considered.
Relaxor ferroelectricity in strained epitaxial SrTiO3 thin films on DyScO3 substrates
Authors: Biegalski M. D. , Jia Y. , Schlom D. G. , Trolier-McKinstry S. , Streiffer S. K. , Sherman V. , Uecker R. , Reiche P.
Published: May 2006

The ferroelectric properties of 500Å thick strained, epitaxial SrTiO3 films grown on DyScO3 substrates by reactive molecular-beam epitaxy are reported. Despite the near 1% biaxial tensile strain, the x-ray rocking curve full widths at half maximum in ω are as narrow as 7arcsec (0.002°). The films show a frequency-dependent permittivity maximum near 250K that is well fit by the Vogel-Fulcher equation. A clear polarization hysteresis is observed below the permittivity maximum, with an in-plane remanent polarization of 10μC∕cm2 at 77K. The high Tmax is consistent with the biaxial tensile strain state, while the superimposed relaxor behavior is likely due to defects.
Instability and dynamics of two nonlinearly coupled laser beams in a plasma
Authors: Shukla P. K. , Eliasson B. , Marklund M. , Stenflo L. , Kourakis I. , Parviainen M. , Dieckmann M. E.
Published: May 2006

The nonlinear interaction between two laser beams in a plasma is investigated in the weakly nonlinear and relativistic regime. The evolution of the laser beams is governed by two nonlinear Schrödinger equations that are coupled with the slow plasma density response. A nonlinear dispersion relation is derived and used to study the growth rates of the Raman forward and backward scattering instabilities as well of the Brillouin and self-focusing/modulational instabilities. The nonlinear evolution of the instabilities is investigated by means of direct simulations of the time-dependent system of nonlinear equations.
Full spectrum enhancement of the light harvesting efficiency of dye sensitized solar cells by including colloidal photonic crystal multilayers
Authors: Mihi A. , López-Alcaraz F. J. , Míguez H.
Published: May 2006

Herein we report a theoretical analysis of the efficiency of dye sensitized solar cells in which colloidal crystals are introduced in different configurations. We find that piling up different lattice constant crystals leads to light harvesting enhancement in the whole dye absorption range. We provide the optimum structural features of such photonic crystal multilayer needed to achieve a photocurrent efficiency enhancement of around 60% with respect to standard dye sensitized solar cells. We demonstrate that this improvement is the result of the optical absorption amplification effect of slow photon resonant modes partially confined within the absorbing part of the cell by the mirror behavior of the colloidal superlattice.
Self-assembled Fe nanodots on Ge(001)
Authors: Jordan K. , Shvets I. V.
Published: May 2006

The initial nucleation of Fe onto the (2×1) reconstructed Ge(001) surface is studied. Uniformly sized two-dimensional Fe dots are shown to nucleate. They have an apparent corrugation height ∼1.1Å and lateral dimensions ∼12×8Å2. Further to their uniform size, due to their registry with respect to the substrate, they are shown to nucleate on a single equivalent surface site. It is suggested that their stability is due to either a “magic” number effect or adsorbate-substrate interactions. Tunneling I(V) spectra show the dot/Ge(001) contact to exhibit marked current rectifying behavior, which is extremely well confined to the contact area.
Si
∕
Si
Ge
-based edge-coupled photodiode with partially p-doped photoabsorption layer for high responsivity and high-power performance
Authors: Shi J.-W. , Chiu P.-H. , Huang F.-H. , Wu Y.-S. , Lu Ja-Yu , Sun C.-K. , Liu C.-W. , Chen P.-S.
Published: May 2006

We demonstrate a Si∕SiG-based edge-coupled photodiode that can achieve high-speed, high output power, and high responsivity performance at a wavelength of 830nm for application to short-reach fiber communication. We incorporate a p-type-doped Si∕Si0.5Ge0.5-based superlattice with a Si-based depletion layer to enhance the photoabsorption process and minimize the hole-trapping problem of the Si∕SiGe multiple quantum well. An extremely high bandwidth-efficiency product performance (10GHz, 276%, 27.6GHz) and high peak output voltage (1.5V) have been achieved simultaneously by operating this device in the avalanche regime.
Monodispersed and highly ordered L10 FePt nanoparticles prepared in the gas phase
Authors: Qiu Jiao-Ming , Wang Jian-Ping
Published: May 2006

We report the direct preparation of monodispersed L10 phase FePt nanoparticles by controlled nucleation and growth using a gas phase aggregation source. These FePt nanoparticles became ordered during their growth in an argon gas flow. They are octahedron faceted with an average size of 5.8nm and a standard size distribution of 11%, as illustrated by transmission electron microscope. Magnetic measurements show that these FePt nanoparticles have coercivities of 8.25kOe at room temperature and 26.5kOe at 50K. This technique provides a novel approach for fabricating nanomaterials with controllable phase and shape in general.
Parametric resonance based scanning probe microscopy
Authors: Moreno-Moreno M. , Raman A. , Gomez-Herrero J. , Reifenberger R.
Published: May 2006

We propose a mode of dynamic scanning probe microscopy based on parametric resonance for highly sensitive nanoscale imaging and force spectroscopy. In this mode the microcantilever probe is excited by means of a closed-loop electronic circuit that modulates the microcantilever stiffness at a frequency close to twice its natural resonance frequency. Under ambient conditions this parametric pumping leads to self-sustained oscillations in a narrow frequency bandwidth thereby resulting in exquisitely sharp, controllable, and non-Lorentzian resonance peaks. We discuss and demonstrate the potential of imaging and force spectroscopy using this mode.
Relaxor ferroelectric behavior of poly(vinylidene fluoride-trifluorethylene) copolymer modified by low energy irradiation
Authors: Faria Luiz O. , Welter Cezar , Moreira Roberto L.
Published: May 2006

We report a relaxorlike modification in the ferroelectric poly(vinylidene fluoride-trifluorethylene) copolymer using ultraviolet (UV) irradiation. This behavior is clearly demonstrated by dielectric measurements. Besides the relaxor feature, the ferroelectric character of the material is retained, also exhibiting Curie transition at barely diminished temperatures. UV-Vis absorption measurements suggests that the UV radiation induces conjugated CC bonds in the copolymer chains. The coexistence of both relaxor and ferroelectric behavior, the lack of chain cross-linking, and a weak reducing in the crystallinity suggest that the UV-induced defects are not sufficient to completely break up the polarization domains.
Detection of subsurface defects using a hybrid heating and cooling imaging technique
Authors: Wang C. , Tang G. C. , Wang W. B. , Zevallos M. , Alfano R. R. , Kassir M. K.
Published: May 2006

A middle infrared imaging technique combining sequential heating and cooling of the material is shown to detect internal defects in composite materials. A low power flash lamp is used as the heat source to raise the temperature of the material above the ambient temperature. Alcohol is spread on the front surface of the heated sample to cause rapid cooling and removal of the thermal wall. This technique induces thermal waves in the composite material, reduces the diffusive photons, and enables recording better images of internal defects by a mid-infrared camera. The technique provides substantial improvement over existing methodologies currently in use for nondestructive evaluation of subsurface defects and cracks in materials.
Surface electronic structure in transition-metal (Cr and Mn) doped GaAs (001) studied by in situ photoemission spectroscopy
Authors: Kanai K. , Okabayashi J. , Toyoda S. , Oshima M. , Ono K.
Published: May 2006

As 3d and Ga 3d photoemission spectra were probed in order to investigate the surface states in transition-metal doped GaAs (001) as spintronics materials. The growth mechanism and chemical bonding states at the surface of III–V-based diluted magnetic semiconductors, Ga1−xMnxAs and Ga1−xCrxAs, have been investigated by angular-dependent in situ photoemission spectroscopy. On low-temperature GaAs grown at 200°C, the difference in core-level photoemission spectra of Ga1−xMnxAs and Ga1−xCrxAs is well related to that in the reflection high-energy electron-diffraction patterns, suggesting that not only As ions but also Ga ions are modulated in Ga1−xMnxAs.
Plasticity of multiscale nanofilamentary Cu∕Nb composite wires during in situ neutron diffraction: Codeformation and size effect
Authors: Thilly L. , Renault P. O. , Vidal V. , Lecouturier F. , Van Petegem S. , Stuhr U. , Van Swygenhoven H.
Published: May 2006

In situ neutron diffraction was performed on Cu∕Nb nanocomposite wires composed of a multiscale Cu matrix embedding Nb nanofilaments with a diameter of 267nm and spacing of 45nm. The evolution of elastic strains and peak profiles versus applied stress evidenced the codeformation behavior with different elastic-plastic regimes: the Cu matrix exhibit size effect in the finest channels while the Nb nanowhiskers remain elastic up to the macroscopic failure, with a strong load transfer from the Cu matrix onto the Nb filaments. The measured yield stress in the finest Cu channels is in agreement with calculations based on a single dislocation regime.
Giant tunneling magnetoresistance in Co2MnSi∕Al–O∕Co2MnSi magnetic tunnel junctions
Authors: Sakuraba Y. , Hattori M. , Oogane M. , Ando Y. , Kato H. , Sakuma A. , Miyazaki T. , Kubota H.
Published: May 2006

Magnetic tunnel junctions (MTJs) with a stacking structure of Co2MnSi∕Al–O∕Co2MnSi were fabricated using magnetron sputtering system. Fabricated MTJ exhibited an extremely large tunneling magnetoresistance (TMR) ratio of 570% at low temperature, which is the highest TMR ratio reported to date for an amorphous Al–O tunneling barrier. The observed dependence of tunneling conductance on bias voltage clearly reveals the half-metallic energy gap of Co2MnSi. The origins of large temperature dependence of TMR ratio were discussed on the basis of the present results.
Temperature dependence of electron-spin coherence in intrinsic bulk GaAs
Authors: Lai Tianshu , Liu Xiaodong , Xu Haihong , Jiao Zhongxing , Wen Jinhui , Lin Weizhu
Published: May 2006

Temperature dependence of electron-spin coherence dynamics is investigated for an intrinsic bulk GaAs in the Voigt geometry using the elliptically polarized absorption quantum-beat spectroscopy. Temperature dependences of spin coherence and recombination lifetimes as well as g factor of electrons are reported over a temperature range from 8.1to260K. The temperature dependence of spin coherence lifetime (T2*) agrees well with a reported theoretical calculation and can be fitted well by a relationship T2*∼T−1∕2, which provides an evidence to support electron-spin decoherence dominated by the Bir-Aronov-Pikus mechanism. The temperature dependence of g factor also agrees well with reported results.
Mesoscopic terahertz photoelectric switch
Authors: Dai Zhenhong , Ni Jun
Published: May 2006

We study the effect of a high-frequency radiation field on the time-dependent dynamical behavior of electron transport in a symmetrical AlGaAs∕GaAs double-barrier structure. The results show that the external radiation field leads to the switching in advance between different current states in current hysteresis region, whose switching time is shorter than 1ps. This property provides the potential to use double-barrier structure as a terahertz high-speed photoelectric switch.
Selective wavelength tuning of self-assembled InAs quantum dots grown on InP
Authors: Barik S. , Tan H. H. , Jagadish C. , Vukmirović N. , Harrison P.
Published: May 2006

We report the experimental results of tuning the emission wavelength of InAs∕InP quantum dots (QDs) by varying either the GaAs interlayer thickness or the indium composition of the InxGa1−xAs interlayer. The InAs QDs are grown on lattice-matched GaInAsP or InP buffers and are capped with an InP layer. As∕P exchange is prominent when the QDs are grown on an InP buffer. A model is developed which considers the As∕P exchange, gallium interdiffusion, strain, and barrier height. Our theoretical and experimental results show that gallium interdiffusion and the As∕P exchange reaction are mainly responsible for the observed shifts in the QD emission wavelength. The model shows that gallium interdiffusion from the interlayer to the InAs QDs grown on a GaInAsP buffer can be utilized to selectively tune the InAs QD emission wavelength over a wide range.
Fabrication of long microchannels with circular cross section using astigmatically shaped femtosecond laser pulses and chemical etching
Authors: Maselli Valeria , Osellame Roberto , Cerullo Giulio , Ramponi Roberta , Laporta Paolo , Magagnin Luca , Cavallotti Pietro Luigi
Published: May 2006

We report on the fabrication of microfluidic channels in fused silica using femtosecond laser irradiation followed by chemical etching. Using an astigmatically shaped beam, we achieve microchannels with circular cross section and length up to 1.5mm. We use the same femtosecond laser, with different irradiation parameters, to fabricate high quality optical waveguides on the same substrate. The integration of microchannels and waveguides will enable a forthcoming class of biophotonic sensors.
Photoluminescence properties of self-assembled InN dots embedded in GaN grown by metal organic vapor phase epitaxy
Authors: Ke W. C. , Fu C. P. , Chen C. Y. , Lee L. , Ku C. S. , Chou W. C. , Chang W.-H. , Lee M. C. , Chen W. K. , Lin W. J. , Cheng Y. C.
Published: May 2006

Photoluminescence (PL) properties of InN dots embedded in GaN were investigated. We observed a systematic blueshift in the emission energy as the average dot height was reduced. The widely size-tunable emission energy can be ascribed to the size quantization effect. Temperature-dependent PL measurements show that the emission peak energies of the dots are insensitive to temperature, as compared with that of bulk film, indicating the localization of carriers in the dots. A reduced quenching of the PL from the InN dots was also observed, implying superior emission properties for the embedded InN dot structures.
Variation in population structure across the ecological range of the Queensland fruit fly, Bactrocera tryoni
Authors: Gilchrist A. S. , Dominiak B. , Gillespie P. S. , Sved J. A.
Published: May 2006

We sampled a pest fruit fly species, the Queensland fruit fly, Bactrocera tryoni, across its entire ecological range in eastern Australia, from ancestral high-density populations in tropical regions through to isolated outbreak populations in marginal arid areas. Using DNA microsatellite markers, we found that in ancestral areas, population differentiation was low and populations were genetically homogeneous over large distances. In more temperate areas, populations were far more genetically differentiated but there was no pattern of isolation-by-distance (no drift/migration equilibrium). Genetic drift appeared to be the major influence on population differentiation. The transition between these extremes was abrupt and unexpectedly far from the species border. Limited geographic structuring among the non-equilibrium populations was apparent from patterns of genetic differentiation, patterns of allelic richness and an ordination analysis. Our results also suggested that there might be recurring migration of flies into a neighbouring quarantine area.
Genetic adaptation by
Pseudomonas aeruginosa
to the airways of cystic fibrosis patients
Authors: Smith Eric E. , Buckley Danielle G. , Wu Zaining , Saenphimmachak Channakhone , Hoffman Lucas R. , D’Argenio David A. , Miller Samuel I. , Ramsey Bonnie W. , Speert David P. , Moskowitz Samuel M. , Burns Jane L. , Kaul Rajinder , Olson Maynard V.
Published: May 2006

In many human infections, hosts and pathogens coexist for years or decades. Important examples include HIV, herpes viruses, tuberculosis, leprosy, and malaria. With the exception of intensively studied viral infections such as HIV/AIDs, little is known about the extent to which the clonal expansion that occurs during long-term infection by pathogens involves important genetic adaptations. We report here a detailed, whole-genome analysis of one such infection, that of a cystic fibrosis (CF) patient by the opportunistic bacterial pathogen
Pseudomonas aeruginosa
. The bacteria underwent numerous genetic adaptations during 8 years of infection, as evidenced by a positive-selection signal across the genome and an overwhelming signal in specific genes, several of which are mutated during the course of most CF infections. Of particular interest is our finding that virulence factors that are required for the initiation of acute infections are often selected against during chronic infections. It is apparent that the genotypes of the
P. aeruginosa
strains present in advanced CF infections differ systematically from those of “wild-type”
P. aeruginosa
and that these differences may offer new opportunities for treatment of this chronic disease.
Cell Cycle-dependent Roles for the FCH-Domain Protein Cdc15p in Formation of the Actomyosin Ring inSchizosaccharomyces pombe
Authors: Wachtler Volker , Huang Yinyi , Karagiannis Jim , Balasubramanian Mohan K.
Published: May 2006

Cell division in the fission yeast Schizosaccharomyces pombe requires the formation and constriction of an actomyosin ring at the division site. The actomyosin ring is assembled in metaphase and anaphase A, is maintained throughout mitosis, and constricts after completion of anaphase. Maintenance of the actomyosin ring during late stages of mitosis depends on the septation initiation network (SIN), a signaling cascade that also regulates the deposition of the division septum. However, SIN is not active in metaphase and is not required for the initial assembly of the actomyosin ring early in mitosis. The FER/CIP4-homology (FCH) domain protein Cdc15p is a component of the actomyosin ring. Mutations in cdc15 lead to failure in cytokinesis and result in the formation of elongated, multinucleate cells without a division septum. Here we present evidence that the requirement of Cdc15p for actomyosin ring formation is dependent on the stage of mitosis. Although cdc15 mutants are competent to assemble actomyosin rings in metaphase, they are unable to maintain actomyosin rings late in mitosis when SIN is active. In the absence of functional Cdc15p, ring formation upon metaphase arrest depends on the anillin-like Mid1p. Interestingly, when cytokinesis is delayed due to perturbations to the division machinery, Cdc15p is maintained in a hypophosphorylated form. The dephosphorylation of Cdc15p, which occurs transiently in unperturbed cytokinesis, is partially dependent on the phosphatase Clp1p/Flp1p. This suggests a mechanism where both SIN and Clp1p/Flp1p contribute to maintenance of the actomyosin ring in late mitosis through Cdc15p, possibly by regulating its phosphorylation status.
Annexin A4 Self-Association Modulates General Membrane Protein Mobility in Living Cells
Authors: Piljić Alen , Schultz Carsten
Published: May 2006

Annexins are Ca2+-regulated phospholipid-binding proteins whose function is only partially understood. Annexin A4 is a member of this family that is believed to be involved in exocytosis and regulation of epithelial Cl−secretion. In this work, fluorescent protein fusions of annexin A4 were used to investigate Ca2+-induced annexin A4 translocation and self-association on membrane surfaces in living cells. We designed a novel, genetically encoded, FRET sensor (CYNEX4) that allowed for easy quantification of translocation and self-association. Mobility of annexin A4 on membrane surfaces was investigated by FRAP. The experiments revealed the immobile nature of annexin A4 aggregates on membrane surfaces, which in turn strongly reduced the mobility of transmembrane and plasma membrane associated proteins. Our work provides mechanistic insight into how annexin A4 may regulate plasma membrane protein function.
Evolutionary turnover of mammalian transcription start sites
Authors: Frith Martin C. , Ponjavic Jasmina , Fredman David , Kai Chikatoshi , Kawai Jun , Carninci Piero , Hayshizaki Yoshihide , Sandelin Albin
Published: May 2006

Alignments of homologous genomic sequences are widely used to identify functional genetic elements and study their evolution. Most studies tacitly equate homology of functional elements with sequence homology. This assumption is violated by the phenomenon of turnover, in which functionally equivalent elements reside at locations that are nonorthologous at the sequence level. Turnover has been demonstrated previously for transcriptionfactor-binding sites. Here, we show that transcription start sites of equivalent genes do not always reside at equivalent locations in the human and mouse genomes. We also identify two types of partial turnover, illustrating evolutionary pathways that could lead to complete turnover. These findings suggest that the signals encoding transcription start sites are highly flexible and evolvable, and have cautionary implications for the use of sequence-level conservation to detect gene regulatory elements.
Absence of contact sensitization to Aloe vera (L.) Burm. f.
Authors: Reider N. , Issa A. , Hawranek T. , Schuster C. , Aberer W. , Kofler H. , Fritsch P. , Hausen B. M.
Published: May 2006

Aloe vera has been used as a cosmetic and medical remedy since ancient times and has gained increasing popularity in recent years. Despite its widespread use, reports of allergic reactions are rare. We patch tested 702 consecutive patients with an oily extract from the leaves, Aloe pulvis from the entire plant and concentrated Aloe vera gel. A specially designed questionnaire was used for the use of Aloe vera, reasons and location of application, adverse reactions, occupation, hobbies and atopy. None of the subjects showed any reaction to one of the preparations. 2 components of the plant have to be distinguished: the bark of the leaves contains anthrachinones with pro‐peristaltic and potential antibiotic and anticancer properties. Constraints have been imposed due to their considerable toxic potential. Today, mostly the Aloe gel from the center of the leaves is processed. It almost exclusively consists of carbohydrates to which also many medical effects have been attributed. Carbohydrates are not likely to induce contact sensitization, which might explain the outcome of our study. However, this does not justify unrestrained promotion of Aloe products, as scientific studies investigating the claims on its constitutional effects are few in number, and the majority of them have been unable to diminish the intuitive scepticism against miracle cures, like Aloe seems to be.
Cosmetic dermatitis in Chinese eczema patients patch tested with a modified European standard series of allergens
Authors: Wang Wen‐Hui , Li Lin‐Feng , Lu Xue‐Yan , Wang Jing
Published: May 2006

The prevalence of cosmetic allergic contact dermatitis (CACD) in Chinese eczema patients (CEP) has not been reported. The purpose of our study was to analyse CACD in CEP and examine the frequency of patch test (PT) reactions to common cosmetic‐related allergens (CRA). 378 consecutive CEP patch tested with a modified European standard series of allergens during a 2‐year period in our clinic were analysed. 73 patients (19.3%) were considered as suspected CACD and 37 patients (9.8%) were confirmed. The frequencies of the positive PT reactions in suspected CACD and confirmed CACD to at least 1 CRA were 64.4% and 89.2%, to para‐phenylenediamine (PPD) were 31.5% and 59.5%, to fragrance mix (FM) were 27.4% and 32.4% and to imidazolidinylurea were 5.5% and 8.1%, respectively. These results were much higher than those of CEP without cosmetic reactions (26.3% for at least 1 CRA, 5.8% for PPD, 8.8% for FM, and 0 for imidazolidinylurea) (P < 0.01 for all, Chi‐square test and Fisher's exact test). These results suggested that CACD is very common in CEP patch tested. PPD and FM are the leading allergens identified. CACD should be strongly considered in CEP with positive PT reactions to PPD, FM and imidazolidinylurea.
Skin capacitance imaging and corneosurfametry. A comparative assessment of the impact of surfactants on stratum corneum
Authors: Xhauflaire‐Uhoda Emmanuelle , Loussouarn Geneviève , Haubrechts Christelle , Léger Didier Saint , Piérard Gérald E
Published: May 2006

Silicon image sensor (SIS) technology was recently introduced as an innovative tool (SkinChip®, L'Oréal) providing sensitive imaging of the skin capacitance. This method can detect discrete focal variations in skin surface hydration, and thus early discrete manifestations of skin irritation induced by surfactants. In the present in vivo study, 2 neat and diluted shampoos, and 5% and 10% sodium laurylsulfate solutions were tested on human skin. Each surfactant solution was gently rubbed on the skin using wet hair wicks mimicking the casual use of a shampoo on the scalp. Clinical and SIS evaluations were carried out. In addition, the same products were tested using the ex vivo corneosurfametry bioassay performed on human stratum corneum (SC) harvested by cyanoacrylate skin surface strippings. The colourimetric index of mildness (CIM) was measured on these samples. The product reactivity with the SC was recognized by darker skin capacitance images, and by both lowered SkinChip®‐generated values and lowered CIM values. The extent in changes varied according to the nature of the test products and their concentrations. The SkinChip® image changes likely corresponded to the acute surfactant‐induced water swelling of the corneocytes. Skin capacitance imaging and corneosurfametry allow to disclose discrete surfactant‐induced alterations of corneocytes.
Cr(III) and Cr(VI) in leather and elicitation of eczema
Authors: Hansen Malene Barre , Menne Torkil , Johansen Jeanne Duus
Published: May 2006

The aim of the present study was to investigate the relation between the content of Cr(VI) and soluble Cr(III) in leather and the ability of the leather to elicit eczema in chromium allergic patients. An array of chromium‐tanned leather samples was analysed for the content of total Cr(VI) and soluble Cr(III) using the DIN 53314 and the DS/EN 420 methods. Subsequently, a group of 15 patients with a history of foot eczema and leather exposure was exposed to a selection of 14 chromium‐ and 1 vegetable‐tanned leather sample on the upper back for 48 hr. In addition, one leather sample was used for a prolonged 14‐day exposure study. In total, 4 of the 15 patients reacted to at least one leather sample, and 5 of the 14 leather samples elicited a reaction in at least 1 patient. The prolonged exposure study demonstrated that an extended exposure period may reveal allergenic potential of a leather sample not otherwise identified using an ordinary 48‐hr exposure period. No relation was observed between the measured content of Cr(VI) and soluble Cr(III) in the leather and the elicitation of eczema. Thus, in order to evaluate the quality of chromium‐tanned leather in relation to preventing allergic skin reactions, other more clinical relevant methods reflecting the actual bioavailable Cr(III) and Cr(VI) fractions should be developed.
The role of T lymphocytes in bone metabolism
Authors: Weitzmann M. Neale , Pacifici Roberto
Published: May 2006

Summary:  Recent findings from animal models suggest that the bone loss induced by estrogen deficiency may stem in large measure from a pathological upregulation of the adaptive immune response. While the role of activated T cells in the osteoporosis driven by inflammatory conditions and infection has been well documented, only recently has the role of T cells in the bone destruction associated with estrogen deficiency begun to be appreciated. In vivo and in vitro models of postmenopausal osteoporosis demonstrate that estrogen deficiency leads to an increase in the adaptive immune function that culminates in an increased production of tumor necrosis factor α (TNF) by activated T cells. TNF increases osteoclast (OC) formation and bone resorption both directly and by augmenting the sensitivity of maturing OCs to the essential osteoclastogenic factor receptor activator of nuclear factor κB ligand. The activation and expansion of TNF‐producing T cells are key steps in estrogen deficiency‐driven bone loss and are regulated by multiple interacting cytokines including transforming growth factor‐β, interleukin‐7, and interferon‐γ, as well as by the process of antigen presentation. Herein, we review the experimental evidence that suggests estrogen prevents bone loss by regulating T‐cell function and immune cell bone interactions.
The role of the immune system in the pathophysiology of osteoporosis
Authors: Clowes Jackie A. , Riggs B. Lawrence , Khosla Sundeep
Published: May 2006

Summary:  The role of the immune system in the development of senile osteoporosis, which arises primarily through the effects of estrogen deficiency and secondary hyperparathyroidism, is slowly being unraveled. This review focuses on our current understanding of how the components of this complex‐interlinked system are regulated and how these fit with previous models of senile and postmenopausal osteoporosis. There is certainly substantial evidence that bone remodeling is a tightly regulated, finely balanced process influenced by subtle changes in proinflammatory and inhibitory cytokines as well as hormones and cellular components that act primarily but not exclusively through the receptor activator of nuclear factor‐κB (RANK)/RANK ligand/osteoprotegerin system. In addition, an acute or chronic imbalance in the system due to infection or inflammation could contribute to systemic (or local) bone loss and increase the risk of fracture. Although significant progress has been made, there remains much to be done in unraveling this complex interaction between the immune system and bone.