bluuebunny/crossref_metadata_2025 huggingface dataset:
Echocardiographic assessment of the aortic valve and left ventricular outflow tract
Authors: Asante-Korang Alfred , Anderson Robert H.
Published: September 2005

The previous reviews in this section of our Supplement1,2 have summarized the anatomic components of the ventriculo-arterial junctions, and then assessed the echocardiographic approach to the ventriculo-arterial junction or junctions as seen in the morphologically right ventricle. In this complementary review, we discuss the echocardiographic assessment of the comparable components found in the morphologically left ventricle, specifically the outflow tract and the arterial root. We will address the echocardiographic anatomy of the aortic valvar complex, and we will review the causes of congenital arterial valvar stenosis, using the aortic valve as our example. We will also review the various lesions that, in the outflow of the morphologically left ventricle, can produce subvalvar and supravalvar stenosis. We will then consider the salient features of the left ventricular outflow tract in patients with discordant ventriculo-arterial connections, and double outlet ventricles. To conclude the review, we will briefly address some rarer anomalies that involve the left ventricular outflow tract, showing how the transesophageal echocardiogram is used to assist the surgeon preparing for repair. The essence of the approach will be to consider the malformations as seen at valvar, subvalvar, or supravalvar levels,1 but we should not lose sight of the fact that aortic coarctation or interruption, hypoplasia of the left heart, and malformations of the mitral valve are all part of the spectrum of lesions associated with obstruction to the left ventricular outflow tract. These additional malformations, however, are beyond the scope of this review.
Outcomes regarding the central nervous system in children with complex congenital cardiac malformations
Authors: Wernovsky Gil
Published: September 2005

The number of children now surviving surgical interventions because of congenital cardiac disease continues to increase. Indeed, it is estimated that, by the end of 2005, there will be more adults than children with congenital cardiac malformations. The complex challenges facing this growing population are only now becoming apparent, including the continued hazard for mortality, the risk of reoperation, and newly-emerging late sequels of surgery. In particular, children with severe lesions requiring intervention in the neonatal period are surviving at levels thought to be highly improbable no more than two decades ago. Heralded by the availability of prostaglandin E1 in the late 1970s, improvements in technology, such as echocardiography, and color Doppler in particular, intensive care and intraoperative support, have recently allowed surgeons to reconstruct the hearts of many children with otherwise lethal defects. Much of the published literature has focused on the cardiac sequels in this population. Increasing attention has recently been given, nonetheless, to the neurodevelopmental outcomes in this population of patients.
Assessing the brain using near-infrared spectroscopy during postoperative ventricular circulatory support
Authors: Giacomuzzi Carmen , Heller Eileen , Mejak Brian , You Jamie , Ungerleider Ross , Silberbach Michael
Published: September 2005

Due to many innovative techniques and technologies, the overall rate of survival for infants undergoing surgical repair of congenital cardiac malformations is excellent. Despite these excellent outcomes, neonates with hypoplasia of the left heart represent a very unique population, and pose difficult challenges for the entire team involved in care. Despite some centers reporting outstanding outcomes, overall rate of survival rate is reported at only 53 percent,1 and survivors often show neurodevelopmental deficits. Many attempts have been made to identify predictors of neurologic outcomes, with heavy concentration around the pre- and peri-operative periods. Little attention has been paid, however, to assessing how attempts at balancing the systemic and pulmonary circulation affect neurodevelopmental outcomes. In the past, we have reported excellent rates of survival with use of routine postoperative circulatory support to augment cardiac output.2,3 This strategy, nonetheless, is still widely debated. It seems plausible that, by augmenting cardiac output in the immediate postoperative period, cerebral perfusion and oxygenation can be optimized, thereby improving neurologic outcomes. In this review, we describe our experience to date in assessing neurological outcomes, and discuss whether outcomes are associated with cerebral saturation and extraction of oxygen during the period of postoperative circulatory assist.
Creating a database with cardioscopy and intra-operative imaging
Authors: Jacobs Jeffrey P. , Elliott Martin J. , Anderson Robert H. , Quintessenza James A. , Chai Paul J. , Morell Victor O. , Botero Luis M. , van Gelder Hugh M. , Badhwar Vinay , Kanani Mazzy , Cohen Gordon A. , Burke Redmond P.
Published: September 2005

The abilities for both computer technology, and intra-operative video-imaging, are evolving rapidly. The merger of these two sciences can be very beneficial, both to congenital cardiac surgeons in general, and in facilitating the creation of a cardioscopic database in particular.
adsonore
Authors: barrett natasha
Published: September 2005

this paper explains the concept, technology and reality of the sound installation adsonore. the important aspects of adsonore are that it is interactive, continuously changing, permanent and located in a public space. the functioning of the human immune system lies behind its interactive design, the real-time sound processes and the physical construction. adsonore is therefore directly related to the building in which it is housed – a new building for biological basic research.
new communications technology in the context of interactive sound art: an empirical analysis
Authors: frisk henrik , yoshida miya
Published: September 2005

in this article we discuss the notion of ‘interaction’, ‘participation’ and ‘the public’ in artistic work, specifically within the context of the exhibition the invisible landscapes (curated by miya yoshida, malmö konstmuseum, 2003) and ethersound (created by henrik frisk), a sound installation displayed in that exhibition. in this work the audience is invited to participate in the creation of new sound events by sending text messages from their mobile phones. thus, our discussion is focused on the space and the mode of participation opened up by new communication technology. based on our experiences of that project, we introduce and explain what we believe are relations of creative production and a different kind of creativity that may emerge from active interaction. we also attempt to describe what we believe an implementation of active public participation can lead to.

we are combining two modes of thinking in this article; one is inspired by a discourse of cultural theories and the other by reflection on our experience of the event. the latter is, by definition, rather subject centred and expansive based on individual observation. we examine and analyse the phenomenon of ‘participation’ whilst playing ethersound as a process of creative production, and seek to reflect upon the power of the co-operative practice and its relation to participation and creativity.
Origin of homochirality in biological systems
Authors: Toxvaerd S.
Published: September 2005

Models for segregation of racemic mixtures of chiral amphiphiles and lipophiles in aqueous solutions show that the amphiphiles with active isomerization kinetics can perform a spontaneous symmetry break during the segregation and self-assemble to homochiral matter. Based on physico-chemical facts, it is argued that D-glyceraldehyde, which was synthesized from the volatiles at the hydrothermal reactors at the origin of life, could be the origin of homochirality in biological systems.
Relicts and models of the RNA world
Authors: Lehto Kirsi , Karetnikov Alexey
Published: September 2005

It is widely believed that the current DNA–RNA–protein-based life forms have evolved from preceding RNA–protein-based life forms, and these again, from mere RNA replicons. By rationale, it can be assumed that the early RNA replicons were fully heterotrophic in terms of obtaining all their building blocks from their environment. In the absence of protein catalysts, their essential life functions had to be mediated by simple functional structures and mechanisms, such as RNA secondary structures, RNA–RNA interactions and RNA-mediated catalysis, and possibly by catalytic minerals or clays. The central role of RNA catalysts in early life forms is supported by the fact that several catalytic RNAs still perform central biological functions in current life forms, and at least some of these may be derived as molecular relicts from the early RNA-based life. The RNA-catalysed metabolic reactions and molecular fossils are more conserved in the eukaryotic life forms than in the prokaryotes, suggesting that the linear eukaryote genomes may more closely resemble the structure and function of the early RNA replicons, than what do the circular prokaryote genomes. Present-day RNA viruses and viroids utilize ultimately simple life strategies, which may be similar to those used by the early RNA replicons. Thus, molecular and functional properties of viruses and viroids may be considered as examples or models of the structures and replication mechanisms, which might have been used for the replication of the early biopolymers.
Venus cloud formation in the meridional circulation
Authors: Imamura Takeshi , Hashimoto George L.
Published: September 2005

A two‐dimensional model study revealed that the meridional circulation can have a large influence on the distributions of the cloud and condensable gases on Venus. In our model, the generally observed depression of near‐infrared optical thickness at midlatitude is reproduced as a result of the enhancement of cloud thickness at low and high latitudes. At high latitudes, the modeled poleward transport of H2SO4‐H2O droplets in the upper atmosphere makes a thick cloud, since most of the H2SO4‐H2O droplets photochemically produced are transported poleward by the meridional circulation. At low latitudes, the modeled large‐scale ascent of the concentrated H2SO4 vapor forms a dense lower cloud in accord with observations by entry probes. The equatorward transport of H2SO4 vapor below the cloud by the modeled meridional circulation and the sedimentation of droplets in the lower cloud leads to the accumulation of H2SO4 vapor around the cloud base at low latitudes. The calculated H2SO4 vapor distribution agrees with radio occultation observations. The middle cloud appears to be caused by the condensation of H2SO4 vapor transported upward from below by convective mixing.
Photochemistry of Pluto's atmosphere and ionosphere near perihelion
Authors: Krasnopolsky Vladimir A. , Cruikshank Dale P.
Published: September 2005

We consider Pluto's photochemistry using a background model for a hydrodynamically escaping atmosphere byKrasnopolsky[1999]. Some adjustments are made in the basic continuity equation and in the boundary conditions to account for hydrodynamic flow in the atmosphere. We model the photochemistry for 44 neutral and 23 ion species. Because of the high methane mixing ratio, Pluto's photochemistry is more similar to that of Titan than that of Triton. Charge exchange between N2+and CH4significantly reduces the production of atomic nitrogen. The most abundant photochemical products are C2H2(3×1017), C4H2(1017), HCN (6×1016), H2(4×1016), C2H4(4×1016), HC3N (3.4×1016), C2H6(2×1016), C3H2(9×1015), and C3H4(8×1015, all in cm−2). In addition to the parent N2, CH4, and CO molecules which absorb photons with λ<145 nm, these products absorb almost completely photons with λ<185 nm, therefore significantly increasing the number of dissociation events. Photochemical losses of the parent species are much smaller than their escape. Precipitation rates are the highest for C2H2, C4H2, HC3N, HCN, C2H6, and C2H4(65, 58, 23, 14, 9, and 6 g cm−2Byr−1, respectively, reduced by a factor of 3 to account for seasonal variations). Escape of photochemical products is highest for H2, H, C2H2, C2H4, HCN, and N (2×1026, 1.4×1026, 6×1024, 3.6×1024, 2.3×1024, and 1.8×1024s−1, respectively). The electron density reaches a maximum of 800 cm−3at 2250 km. The most abundant ions are HCNH+, C3H3+, and C3H5+. Some of the photochemical products might be detected using the technique of UV solar occultation spectroscopy from a spacecraft flyby.
Contributions of diffusion, dissolution, ion exchange, and leakage from low‐permeability layers to confined aquifers
Authors: Atteia O. , Andre L. , Dupuy A. , Franceschi M.
Published: September 2005

In this paper the evolution of the groundwater chemical composition in aquifers from large sedimentary basins over geological timescale is investigated. The solutes upon which we focus are sulfate, chloride, and sodium because they often display concentration gradients at the regional scale and they are largely undersaturated with respect to any mineral. To explain these gradients, several phenomena are studied: leakage, dissolution of minerals or ion exchange within an aquifer, and dissolution of minerals or ion exchange from an overlying aquitard. Assuming local equilibrium, the study of dissolution within the aquifer shows that the minerals containing sulfate and chloride must have been leached out rapidly after aquifer flushing and should not exist after one million years of water flow. In addition, a simplified model of leakage shows that dissolution of minerals embedded in an aquitard could deliver a flux of ions able to explain significant gradients within the aquifer. Without water transfer from aquitard to aquifer, diffusion from the aquitard can also lead to significant concentration gradient along the aquifer. A detailed study of ion exchange shows that the clays existing in the aquifer are rapidly (thousands of years) saturated with calcium and will not release sodium later. On the other hand, exchange from the aquitard clays, followed by diffusion, is able to change sodium and calcium concentrations significantly over geological time intervals in the aquifer. The intensities of each process studied are compared. It is shown that given the assumptions made, the influence of each process can be differentiated where the aquifer‐aquitard system is well enough characterized. Analysis of aquifers with clay beds, detailed in the discussion, suggests that these layers may play a secondary role over geological timescales. However, they can lead to disconnected parts of the aquifer that can show different water chemistry. Our work suggests that the composition of major aquitards may have a significant effect on the chemistry of the aquifer water.
Outflow of energetic ions from the magnetosphere and its contribution to the decay of the storm time ring current
Authors: Keika K. , Nosé M. , Ohtani S. , Takahashi K. , Christon S. P. , McEntire R. W.
Published: September 2005

We statistically and quantitatively examine the outflow of energetic ions from the magnetosphere during magnetic storms. We also evaluate the contribution of the outflow to the decay of the ring current. We use energetic ion (9–210 keV) data obtained by the energetic particle and ion composition (EPIC) instrument and magnetic field data obtained by the magnetic field measurements (MGF) system, both on board the Geotail spacecraft. The outflowing energy flux, that is, the energy flux lost by ring current ions flowing through the magnetopause, is defined as the energy flux normal to the magnetopause and is calculated based on measurements made adjacent to the earthward side of the low‐latitude boundary layer. Our statistics show that the outflowing energy flux is about 105–108 keV/(cm2s) during both the main phase and the recovery phase. It is higher on the afternoonside than on the morningside. It is better correlated with the square root of the dynamic pressure of the solar wind than the electric field of the solar wind, which is a proxy for the strength of the convection electric field. The contribution of the outflow to the rapid decay of the ring current is estimated to be at least 23% and could be much higher than 23% for the 23 September 2001 storm, based on an underestimated leakage area which is determined from magnetic field measurements. We suggest that the drift governing the ion outflow mainly is the ∇B drift which has a radial component that arises from a day‐night gradient of the magnetic field in the magnetosphere caused by the solar wind compression. We conclude that the ion outflow contributes significantly to the rapid decay of the ring current, even in the case of a sudden northward turning of the interplanetary magnetic field which causes a sudden decrease in the convection electric field.
Similarity analysis of subsurface flow response of hillslopes with complex geometry
Authors: Berne A. , Uijlenhoet R. , Troch P. A.
Published: September 2005

The matter of the efficient and parsimonious parameterization of hillslope subsurface flow remains an important issue in catchment hydrological studies (Brutsaert, 1995). Insights into the influence of the shape and hydraulic characteristics of hillslopes is required to further our understanding and our ability to model catchment hydrological processes. Recently, Troch et al. (2003) introduced the hillslope‐storage Boussinesq (HSB) equation to describe subsurface flow and saturation along geometrically complex hillslopes. The HSB equation can be linearized and further reduced to an advection‐diffusion equation for subsurface flow in hillslopes with constant bedrock slopes and exponential width functions. This paper presents a dimensional analysis of the latter equation in order to study the moments of the characteristic response function (CRF), corresponding to the free drainage of this type of hillslope. These moments, in a dimensionless form, can be expressed as functions of a similarity parameter, hereafter called the hillslope Péclet number, and a group of dimensionless numbers accounting for the effects of the boundary and initial conditions. The analytical expressions for the first four central CRF moments are derived for two types of initial conditions. The analysis of their respective influences shows that the hillslope Péclet number is an efficient similarity parameter to describe the hillslope subsurface flow response. Moreover, comparison between the CRF moments predicted by means of our similarity analysis and empirical moments derived from outflow measurements for different types of laboratory hillslopes shows good agreement.
One more step toward a warmer Arctic
Authors: Polyakov Igor V. , Beszczynska Agnieszka , Carmack Eddy C. , Dmitrenko Igor A. , Fahrbach Eberhard , Frolov Ivan E. , Gerdes Rüdiger , Hansen Edmond , Holfort Jürgen , Ivanov Vladimir V. , Johnson Mark A. , Karcher Michael , Kauker Frank , Morison James , Orvik Kjell A. , Schauer Ursula , Simmons Harper L. , Skagseth Øystein , Sokolov Vladimir T. , Steele Michael , Timokhov Leonid A. , Walsh David , Walsh John E.
Published: September 2005

This study was motivated by a strong warming signal seen in mooring‐based and oceanographic survey data collected in 2004 in the Eurasian Basin of the Arctic Ocean. The source of this and earlier Arctic Ocean changes lies in interactions between polar and sub‐polar basins. Evidence suggests such changes are abrupt, or pulse‐like, taking the form of propagating anomalies that can be traced to higher‐latitudes. For example, an anomaly found in 2004 in the eastern Eurasian Basin took ∼1.5 years to propagate from the Norwegian Sea to the Fram Strait region, and additional ∼4.5–5 years to reach the Laptev Sea slope. While the causes of the observed changes will require further investigation, our conclusions are consistent with prevailing ideas suggesting the Arctic Ocean is in transition towards a new, warmer state.
Pi2 pulsations observed from the Polar satellite outside the plasmapause
Authors: Kim K.‐H. , Lee D.‐H. , Takahashi K. , Russell C. T. , Moon Y.‐J. , Yumoto K.
Published: September 2005

Recently, Lee and Lysak (1999) suggested that Pi2 pulsations in the inner magnetosphere originate from plasmaspheric virtual resonances (PVR). The PVR model predicts that Pi2 pulsations are not strictly localized to the plasmasphere. Until now there have been no spacecraft observations of the PVR mode outside the plasmasphere. Motivated by the theoretical work, we examine Pi2 pulsations simultaneously observed by the Polar satellite outside the plasmapause and at the low‐latitude Kakioka (L = 1.3) station. We identify 14 events to have high coherence (> 0.7) between the compressional component (bz) in space and the horizontal component (H) at Kakioka during a 2‐month period in 1997. The H‐bz cross phase is ∼180° regardless of the satellite's distance from the plasmapause. The amplitude of the Pi2 pulsations tends to decrease with the distance. On the basis of these observations, we conclude that the PVR mode is an appropriate model for our Pi2 events observed outside the plasmasphere.
Static, transient, and dynamic phase coexistence in metal nanoclusters
Authors: Schebarchov D. , Hendy S. C.
Published: September 2005

Molecular dynamics simulations are used to examine static and dynamic coexistence between solid and liquid phases in nanoscale silver, copper, and nickel clusters. We find static coexistence in the 561-atom copper icosahedron, the 561-atom silver icosahedron, and the 923-atom nickel icosahedron, and in cluster sizes above these thresholds, but not in smaller clusters. Nonetheless, in smaller clusters we typically observe either dynamic coexistence between fully solid and liquid states or transient coexistence which is essentially dynamic coexistence between a fully solid state and a solid-liquid state.
On the orientational relaxation of HDO in liquid water
Authors: Rezus Y. L. A. , Bakker H. J.
Published: September 2005

We use femtosecond mid-infrared pump-probe spectroscopy to study the orientational relaxation of HDO molecules dissolved in H2O. In order to obtain a reliable anisotropy decay we model the effects of heating and correct for these effects. We have measured the reorientation time constant of the OD vibration from 2430to2600cm−1, and observe a value of 2.5ps that shows no variation over this frequency interval. Our results are discussed in the context of previous experiments that have been performed on the complementary system of HDO dissolved in D2O.
Variational approach to nonlinear evolution of modulational instability using one-dimensional Zakharov equations
Authors: Sharma R. P. , Batra K. , Das S. S.
Published: September 2005

The Ritz variational method has been applied to the Zakharov equations to construct a model for the nonlinear evolution of modulational instability. Spatiotemporal chaos and nonlinear evolution patterns of the modulational instability are investigated theoretically by choosing an appropriate trial function for the field for periodic field and density perturbations. The spatially periodic field trial function was chosen in the form of a combination of Jacobian elliptic functions with the dependence of its parameters subject to optimization. It is found that these evolutions are quite sensitive to the initial conditions, recurrence is broken up and a chaotic state develops. Theoretical predictions with the chosen trial function compare well with numerical solutions to the Zakharov equations through spectral methods, the extent of comparison being dependent on a suitable choice of the trail function.
Conducting Ni nanoparticles in an ion-modified polymer
Authors: Sze J. Y. , Tay B. K. , Pakes C. I. , Jamieson D. N. , Prawer S.
Published: September 2005

Conductive-atomic force microscopy has been used to perform nanoscale current imaging of Ni-ion-implanted polythylene terephthlate films. A reduction in bulk sheet resistivity, as the Ni dose is increased, is found to be accompanied by an evolution in local conductivity from a spatially homogeneous insulator to an interconnected network of conducting Ni crystallites. The crystallites have a mean dimension of 12.3nm, confirmed by x-ray-diffraction analysis.
Nanostructural and electrical properties of functionally terminated self-assembled monolayers on silicon surfaces
Authors: Rittner M. , Martin-Gonzalez M. S. , Flores A. , Schweizer H. , Effenberger F. , Pilkuhn M. H.
Published: September 2005

Self-assembled monolayers (SAMs) having alkyl chains with typically 18 CH2 units and with different functional end groups (methyl, thiol, thiophene, phenoxy, and biphenyl) have been attached to hydroxylated (100) silicon surfaces. Their layer structure has been studied using grazing incidence x-ray reflectometry. An excellent data analysis is possible on the basis of a two layer model. One layer with constant thickness (about 10.8Å) for all the SAMs investigated is associated with the alkyl chain/silicon interface, whereas the second layer is associated with the functional end group. Its dimension changes with the size and nature of the end group. The layer dimension increases from about 22Å for the smallest end group (methyl) to about 32Å for the largest one (biphenyl). The experimental layer thickness values are in good agreement with those expected from molecular modeling. The electrical properties of the SAM layers have been studied using Au∕Al contacts deposited on the functional end groups. Of particular interest are the insulating properties of the alkyl chain and the breakdown voltages which exhibit very high values of typically 16MV∕cm. A lateral in-plane conductance along the end groups has been measured in the case of an I2-doped biphenyl end group. Iodine doping can increase the conductivity by a factor of 12–14. This suggests the possibility of a nanomolecular transistor with the functional end group as an active layer without any additional deposition of an organic conducting layer on the SAM dielectric layer.
Three-dimensional distribution of the spin-polarized current inside nanostructures
Authors: Hamrle J. , Kimura T. , Yang T. , Otani Y.
Published: September 2005

We present a formalism to determine the three-dimensional (3D) distribution of the spin-polarized current and electrochemical potential inside arbitrary nanostructures such as magnetic/nonmagnetic layered pillars, etc. The model is based on dividing the nanostructure into a 3D electric circuit of spin-dependent-resistor elements, inside each of which the propagation is treated as a one-dimensional problem. The solutions presented here are calculated in the diffusive transport regime for the parallel/antiparallel magnetic states.
Effective thermal conductivity of two-phase functionally graded particulate composites
Authors: Yin H. M. , Paulino G. H. , Buttlar W. G. , Sun L. Z.
Published: September 2005

A multiscale modeling method is proposed to derive effective thermal conductivity in two-phase graded particulate composites. In the particle-matrix zone, a graded representative volume element is constructed to represent the random microstructure at the neighborhood of a material point. At the steady state, the particle’s averaged heat flux is solved by integrating the pairwise thermal interactions from all other particles. The homogenized heat flux and temperature gradient are further derived, through which the effective thermal conductivity of the graded medium is calculated. In the transition zone, a transition function is introduced to make the homogenized thermal fields continuous and differentiable. By means of temperature boundary conditions, the temperature profile in the gradation direction is solved. When the material gradient is zero, the proposed model can also predict the effective thermal conductivity of uniform composites with the particle interactions. Parametric analyses and comparisons with other models and available experimental data are presented to demonstrate the capability of the proposed method.
Effects of Al doping on the thermoelectric performance of CoSi single crystal
Authors: Li C. C. , Ren W. L. , Zhang L. T. , Ito K. , Wu J. S.
Published: September 2005

Thermoelectric transport properties of CoSi1−xAlx single crystals have been measured over the temperature range from 300to973K to investigate the effects of Al substitution on the electrical resistivity, Seebeck coefficient, and thermal conductivity. The solubility limit of Al substitution for Si in CoSi is found to be in the range of 0.2⩽x<0.3. The electrical resistivity increases with increasing Al substitution x and reaches a maximum at x=0.08. When x is further increased, there is a drop in the electrical reisitivity between 300 and 550K and there is almost no change at higher temperatures. The Seebeck coefficients of CoSi1−xAlx single crystals shift towards the positive direction compared to that of the binary crystal over the entire measured temperature range. The Seebeck coefficient decreases as a function of temperature. The thermal conductivity and the figure of merit decrease significantly with increasing Al content. The decrease in thermal conductivity is mainly attributed to the additional scattering from Al atoms.
Nonlinear dynamics of piezoelectric high displacement actuators in cantilever mode
Authors: Usher Tim , Sim Alec
Published: September 2005

Experimental results of the nonlinear dynamic response of a piezoelectric high displacement actuator known as thin-layer composite unimorph ferroelectric driver and sensor were compared to a theoretical model, which utilizes the multiple scales method to connect the effective spring constant to higher-order stiffness constants c4 of the piezoelectric layer. This type of actuator has prestress gradients resulting from the manufacturing process that have been reported to play an important role in enhanced actuation. A value of c4=−4.7×1020N∕m2 was obtained for the higher-order lead zirconate titanate (PZT) stiffness coefficient, which is higher than other published results for PZT without prestress gradients. Peak resonance displacements over 1mm were obtained for even small (100Vpp) applied fields. The analysis showed a slight voltage dependence that was not specifically accounted for in the theory. This was confirmed by recasting data from other published results and further confirmed by dc offset studies reported here.
Theory of strain states in InAs quantum dots and dependence on their capping layers
Authors: Nabetani Y. , Matsumoto T. , Sasikala G. , Suemune I.
Published: September 2005

The dependence of strain states in InAs self-assembled quantum dots (QDs) on their capping layers was investigated by valence-force field model calculations. An InAs QD on (001) GaAs and embedded in a GaNAs capping layer and the one with its dot surface terminated with nitrogen (N) and embedded in a GaAs capping layer show reduced compressive strain within the QDs in the (001) growth plane due to the lateral expansion of the QDs, while the one embedded in an InGaAs capping layer shows enhanced tensile strain along the [001] growth direction. The strain energies around the center of the InAs QDs with the GaNAs capping layer and with the N-surface termination are lowered compared with those for conventional GaAs capping layers. The burying conditions of InAs QDs also modify the sizes of QDs. The stress distributions obtained by strain energy mapping showed that In atoms around the top of QDs undergo inward stress. This inward stress prevents In segregation and explains the experimentally observed improved optical properties of GaNAs-embedded and N-terminated QDs.
Interface alloy mixing effect in the growth of self-assembled InP quantum dots on InAlGaP matrices by metalorganic chemical-vapor deposition
Authors: Zhang X. B. , Ryou J. H. , Dupuis R. D. , Walter G. , Holonyak N.
Published: September 2005

We report on the growth of InP self-assembled quantum dots (SAQDs or simply QDs) on In0.5(AlxGa1−x)0.5P matrices grown on (001) GaAs substrates by metalorganic chemical-vapor deposition. We find that the size of InP QDs grown on the In0.5Al0.5P matrix decreases and the density increases when the QD growth temperature decreases. However, cathodoluminescence (CL) studies of the capped InP QDs show that the CL peak of InP QDs redshifts when the QD growth temperature decreases. These results suggest that there is a strong interface mixing during the growth of InP∕In0.5Al0.5P QDs, in which some InAlP materials in the lower and upper barriers mix with the InP QDs and form InAlP alloy QDs. Postgrowth thermal annealing of these QDs in N2 shows that our QDs are quite stable after annealing at the growth temperature for a time equal to the upper In0.5Al0.5P barrier growth time. Combined with the thermal annealing study, we think the interface mixing between the InP QDs and In0.5Al0.5P layers happens mainly during the initial growth of InP and the initial capping of InP QDs with In0.5Al0.5P.
Reducing the critical current for short-pulse spin-transfer switching of nanomagnets
Authors: Braganca P. M. , Krivorotov I. N. , Ozatay O. , Garcia A. G. F. , Emley N. C. , Sankey J. C. , Ralph D. C. , Buhrman R. A.
Published: September 2005

We have fabricated permalloy∕copper∕permalloy nanopillar spin valves designed to reduce the critical current for spin-transfer switching while maintaining thermal stability of the free layer. Pulsed current amplitudes necessary for switching a 4.5-nm-thick permalloy free layer range from 0.4mA for a 100ns pulse to 2mA for a 1ns pulse, showing that the magnetization must be overdriven to achieve switching on short time scales. Comparisons to Landau–Lifshitz–Gilbert simulations indicate an effective damping parameter ≈0.03 and spin-torque efficiencies for parallel-to-antiparallel and antiparallel-to-parallel switching that are more symmetric than predicted by recent theoretical models.
Ti
O
2
single-crystalline nanorod electrode for quasi-solid-state dye-sensitized solar cells
Authors: Song Mi Yeon , Ahn Young Rack , Jo Seong Mu , Kim Dong Young , Ahn Jae-Pyoung
Published: September 2005

Ti O 2 single-crystalline nanorods are prepared from electrospun fibers which are composed of nanofibrils with an islands-in-a-sea morphology. The mechanical pressure produces each fibril into nanorods which are converted to anatase single crystals after calcination. High-resolution transmission electron microscopy shows that the (001) plane is growing along the longitudinal direction of the rod. In this work, the nanorod electrode provides the efficient photocurrent generation in a quasi-solid-state dye-sensitized solar cell using highly viscous poly(vinylidenefluoride-co-hexafluoropropylene)-based gel electrolytes. The overall conversion efficiency of the TiO2 nanorods shows 6.2% under 100mW∕cm2 (AM 1.5G) illumination.
On the normalized turbulent energy dissipation rate
Authors: Burattini P. , Lavoie P. , Antonia R. A.
Published: September 2005

This paper revisits values of the normalized energy dissipation rate (Cϵ) in different flows (two-dimensional wakes, grid turbulence, and homogeneous shear flow). Previously published as well as new data are considered over a relatively wide range of the Taylor-microscale Reynolds number Rλ. Cϵ exhibits wide scatter (in the range 0.5–2.5 for Rλ>50) although, for a given flow and initial conditions, it is independent of Rλ when the latter is sufficiently large. An alternative definition [B. R. Pearson, P.-Å. Krogstad, and W. van de Water, “Measurements of the turbulent energy dissipation rate,” Phys. Fluids 14, 1288 (2002)] of Cϵ has been checked in the same flows but has failed to yield a universal value for the coefficient.
Analytical bond orbital model: Heterobond effect on optical properties of InAs∕GaSb superlattices
Authors: Chen Chun-Nan
Published: September 2005

This paper develops an efficient bond orbital model with analytical expressions to investigate the optical properties of InAs∕GaSb superlattices. In contrast to the conventional bond orbital model, the proposed method expresses the momentum matrix elements entirely in terms of Hamiltonian matrix elements without introducing any additional optical parameters. The existence of In–Sb and Ga–As heterobonds across the InAs∕GaSb superlattice interfaces causes giant optical variations to be manifested in the momentum matrix element, absorption coefficient, and refractive index.
Intrathymic administration of hematopoietic progenitor cells enhances T cell reconstitution in ZAP-70 severe combined immunodeficiency
Authors: Adjali Oumeya , Vicente Rita R. , Ferrand Christophe , Jacquet Chantal , Mongellaz Cédric , Tiberghien Pierre , Chebli Karim , Zimmermann Valérie S. , Taylor Naomi
Published: September 2005

Patients with severe combined immunodeficiency (SCID) present with opportunistic infections that are almost universally fatal in infancy. The mainstay treatment for these patients is allogeneic hematopoietic stem cell (HSC) transplantation, but sustained polyclonal T cell reconstitution is too often unsatisfactory. Although transplantation is conventionally performed by i.v. administration of HSC, we hypothesized that an intrathymic strategy would be superior. Indeed, several progenitor cell populations are incapable of homing to the thymus, the major site of T cell differentiation, and it appears that there are extensive time periods during which the thymus is refractory to progenitor cell import. To test this hypothesis, nonconditioned infant ZAP-70-deficient SCID mice were intrathymically injected with WT bone marrow progenitor cells, a procedure accomplished without surgical intervention. Upon intrathymic HSC injection, there was a more rapid T cell differentiation, with mature thymocytes detected by 4 weeks after transplantation. Intrathymic injection of HSC also resulted in significantly higher numbers of peripheral T cells, increased percentages of naïve T cells, and more diverse T cell receptor repertoires. Moreover, T cell reconstitution after intrathymic transplantation was obtained after injection of 10-fold fewer donor HSC. Thus, this intrathymic transplantation approach may improve the outcome of SCID patients by enhancing T cell reconstitution.
Iron fortification of infant formula
Authors: Moy R. J. D
Published: September 2005

The purpose of this review is to examine the need for and appropriate level of Fe fortification of infant formula, and to assess any adverse effects of Fe fortification. The appropriate level of Fe fortification of infant formula has been established through studies of Fe absorption or erythrocyte incorporation of Fe, and through clinical trials of formulas with varying levels of Fe that were aimed at preventing the development of Fe deficiency in participating infants. In addition, the effects of varying levels of Fe fortification on the absorption of other minerals and trace elements, and on the incidence of infection and immune function have been studied, as has the effect of adding bovine lactoferrin to formula. Studies of Fe absorption have shown that increasing the level of Fe fortification in formula does not significantly increase the amount absorbed, and that the addition of bovine lactoferrin is unlikely to further increase absorption of Fe. Quite different recommendations for the level of Fe fortification of formula are made in the USA and in Europe. The higher level (12 mg/l) commonly used in the USA is not well supported by the evidence from clinical trials that suggest that lower levels (4 mg/l or less) may be adequate to prevent the development of Fe deficiency. Higher levels of Fe fortification may also interfere with the absorption of other minerals such as Cu and Se. Concerns about potential adverse effects of Fe fortification on immune function and susceptibility to infections have been disproved as have concerns about associated gastrointestinal symptomatology. There are no clearly demonstrated advantages in using ‘follow-on’ formula with high Fe content (up to 13 mg/l) instead of the standard UK formulas with Fe fortification in the range 4–7 mg/l after the age of 6 months, although they may provide an important ‘safety net’ for the prevention of Fe deficiency in communities with weaning diets low in Fe.
Bioavailability of energy, nitrogen, fat, zinc, iron and calcium from rural and urban mexican diets
Authors: Rosado Jorge L. , Lopez Patricia , Morales Maria , Munoz Elsa , Allen Lindsay H.
Published: September 2005

The availabilities of nutrients from a representative rural Mexican diet (RMD) and a representative urban Mexican diet (UMD) were evaluated by balance experiments in sixteen Mexican women. Compared with UMD, the plant-based RMD led to a higher number of defaecations and higher faecal excretion of dry matter, fat, nitrogen and energy. Apparent digestibility of N from RMD was only 67% compared with 90% from UMD. N balance was 0.4 and 2.6 g/d with RMD and UMD respectively (P < 0.001). Apparent digestibility of energy was 89 and 95% from RMD and UMD respectively (P < 0.001). Calculation of the metabolizable energy (ME) using Atwater's (Atwater & Bryant, 1900) general factors overestimates the determined ME in RMD by 8%. The Food and Agriculture Organization/World Health Organization/United Nations University (World Health Organization, 1985) recommended factors for correction of digestibility of fibre intake overestimate energy and protein absorption from RMD. The diets provided similar amounts of zinc, and its apparent absorption from RMD was 0.5 mg/d (4.6%) and its balance was 0.1 mg/d. This compared with values for UMD of 1.6 mg/d (16%) and 1.2 mg/d respectively. Iron intake was higher from RMD (17.4 v. 11.6 mg/d; P < 0.01), but apparent absorption was 17 v. 35% and balance was 2.7 and 3.8 mg/d (P < 0.001) for RMD and UMD respectively. RMD also contained more calcium (745 v. 410 mg/d) but apparent absorption from RMD was negative (−136 v. 15 mg/d) and balance was more negative (−197 v.−77 mg/d; P < 0.05). Thus, the content of these minerals is not low in the rural diet but their bioavailabilities are poor.
Effect of ileo-rectal anastomosis and post-valve T-caecum cannulation on growing pigs
Authors: Köhler T. , Verstegen M. W. A. , Mosenthin R. , Wensing T. , Den Hartog L. A. , Huisman J.
Published: September 2005

In a long-term study nine ileo-rectally anastomosed (IRA) and seven post-valve T-caecum (PVTC)-cannulated pigs were compared with six intact pigs with regard to different blood variables, sodium and potassium retention and weights of selected organs. After surgery, apart from urea and K measured 13 weeks post-surgery, there were no differences in the blood variables between the PVTC-pigs and intact pigs. In IRA-pigs concentrations of creatinine (P < 0.01), Na (P < 0.001), base excess (P < 0.001), pH (P < 0.01) and bicarbonate (P < 0.001) in blood were lower than those in intact pigs. At 13 weeks after surgery the blood K concentration in IRA-pigs was higher (P < 0.001) than that in PVTC-pigs or intact pigs. At 6 weeks after surgery the blood urea concentration in IRA-pigs was higher (P < 0.001) than that in intact and PVTC-pigs. At 13 weeks after surgery the urea concentration in PVTC-pigs was higher (P < 0.001) than those in IRA-pigs or intact pigs. The Na (P < 0.01 11 weeks after surgery) and (P < 0.05 and P < 0.01 5 and 11 weeks after surgery respectively) balances in IRA-pigs were lower than those in intact animals. Na retention was negative for IRA-animals 11 weeks after surgery. Na and K retentions were similar in PVTC-pigs and in intact pigs. The urinary: faecal excretion of Na differed slightly between PVTC-animals and intact animals. At 13 weeks after surgery there were no differences in organ weights between the PVTC-pigs and intact animals. In the IRA-pigs the weights of the liver (P > 0.05), the kidneys (P > 0.05) and the adrenal glands were higher (P < 0.001) than those in the intact animals.
Evaluation of the nutritive value of yellow rice in rats and broiler chicks
Authors: Panigrahi S. , Phillips S. , Plumb V. E. , Watson A. J.
Published: September 2005

Yellow discoloration often develops in rice kernels during post-harvest storage, due possibly to fungal activity. The present study examined the changes in nutrient composition taking place during yellowing of rice, and the effects of feeding rats and broiler chicks on a moderately yellow rice at 600 g/kg diet. Nitrogen content was found to be higher in rice grains that had become more yellow, only part of the increase being in non-protein-N; however, relative to crude protein (N x 6.25) the concentrations of lysine, methionine, cystine and arginine were lower. There were no significant differences between white and yellow rice in the food intake, weight gain and efficiency of food utilization (EFU) of rats and chicks when diets were formulated to contain similar nutrient concentrations, or the same basal ingredient composition. Diet pelleting increased food intake and weight gain in both animal species, but reduced dry matter and energy digestibility in rats; effects on nutrient retention in chicks were largely non-significant. Liver weights of rats and chicks and pancreas weights of chicks were unaffected by yellow rice; however, chicks fed on mash had a larger pancreas on average than those fed on pellets. Thus, whilst the nutrient composition of rice is altered during yellowing, a moderately yellow rice is unlikely to produce major adverse effects when fed to rats and broiler chicks.
Changes in insulin-receptor mRNA levels in skeletal muscle and brown adipose tissue of weanling rats during fasting and refeeding
Authors: Knott Rachel M. , Trayhurn Paul , Hesketh John E.
Published: September 2005

Tissue-specific alterations in insulin sensitivity occur in response to fasting and refeeding, as part of the integrated adaptive mechanisms employed to adjust to major changes in nutritional status. In the present study the effects of fasting and refeeding on insulin-receptor, actin and myosin mRNA levels in skeletal muscle, and insulin-receptor and uncoupling-protein mRNA in brown adipose tissue of rats have been examined. Insulin-receptor mRNA levels increased markedly in both skeletal muscle and brown adipose tissue after a 40 h fast, the increase being greater in brown fat (8-fold) than in muscle (2-fold). On refeeding for 4 h, the insulin-receptor mRNA level in both tissues declined rapidly to control levels. An increase in insulin-receptor mRNA level was also observed in brown adipose tissue after a 16 h fast, although not in skeletal muscle. In contrast to the insulin-receptor mRNA, the level of the mRNA for the mitochondrial uncoupling protein declined markedly in brown adipose tissue during a 40 h fast. These results indicate that insulin-receptor mRNA levels are modulated in response to the alterations in nutritional status that occur during fasting and refeeding; this may reflect a nutritional influence on transcription of the receptor-protein gene