bluuebunny/crossref_metadata_2025 huggingface dataset:
Separation of triacylglycerols in a complex lipidic matrix by using comprehensive two‐dimensional liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometric detection
Authors: Dugo Paola , Kumm Tiina , Chiofalo Biagina , Cotroneo Antonella , Mondello Luigi
Published: April 2006

The present investigation describes the employment of a comprehensive 2‐D HPLC system, based on the combination of a silver ion and an RP column, for the characterization of the triacylglycerol (TAG) fraction of a very complex lipidic sample: donkey milk fat. The TAGs were grouped on the resulting bidimensional contour plot according to their double bond numbers (aligned along vertical bands) and according to their partition numbers (aligned along horizontal bands). Peak assignment was supported by using atmospheric pressure chemical ionization mass spectrometric (APCI‐MS) detection. The combination of the enhanced resolving power of comprehensive multidimensional LC, the formation of ordered 2‐D patterns, and APCI‐MS detection proved to be an effective tool for the characterization of the complex matrix, enabling the separation and identification of nearly 60 TAGs.
A Model for Efficient Assay Development and Screening at a Small Research Site
Authors: Simpson Peter B.
Published: April 2006

Creating an automated assay team with multiple skills that can support diverse screening responsibilities is a key challenge for drug discovery research sites. Development of ultra high throughput screening (uHTS) screens, development of lead identification and lead optimization assays within medicinal chemistry supported projects, and automation and miniaturization of assays are best performed by a dedicated team of varying backgrounds, experience, and skill sets. This article discusses how integration with therapeutic franchises, regular communication processes, and formal and informal cross-training facilitate the establishment of a streamlined and efficient model at our site for supporting multiple projects at relatively modest financial outlay and recruitment levels.
On the nature of unsteady three-dimensional laminar boundary-layer separation
Authors: Williams James C.
Published: April 2006

Solutions have been obtained for a family of unsteady three-dimensional boundary-layer flows which approach separation as a result of the imposed pressure gradient. These solutions have been obtained in a co-ordinate system which is moving with a constant velocity relative to the body-fixed co-ordinate system. The flows studied are those which are steady in the moving co-ordinate system. The boundary-layer solutions have been obtained in the moving co-ordinate system using the technique of semi-similar solutions. The behaviour of the solutions as separation is approached has been used to infer the physical characteristics of unsteady three-dimensional separation.

In the numerical solutions of the three-dimensional unsteady laminar boundary-layer equations, subject to an imposed pressure distribution, the approach to separation is characterized by a rapid increase in the number of iterations required to obtain converged solutions at each station and a corresponding rapid increase in the component of velocity normal to the body surface. The solutions obtained indicate that separation is best observed in a co-ordinate system moving with separation where streamlines turn to form an envelope which is the separation line, as in steady three-dimensional flow, and that this process occurs within the boundary layer (away from the wall) as in the unsteady two-dimensional case. This description of three-dimensional unsteady separation is a generalization of the two-dimensional (Moore-Rott-Sears) model for unsteady separation.
Experiments on convective layer formation and merging in a differentially heated slot
Authors: Wirtz R. A. , Reddy C. S.
Published: April 2006

This work describes experiments in which a stably stratified salt solution is subjected to steady lateral temperature gradients. The criteria for the onset of layered convection are observed to agree with previously published stability analysis. Convective layers formed in this way are found to be statically unstable; they always merge two into one to form a new system. This process continues until the density jump at the solute interface between layers is larger than the density deficit produced by the side wall heating/cooling. The eventual stable system develops into well-mixed convective layers separated by sharp solute interfaces. The conditions for any subsequent layer intermixing and its effect on the lateral heat transfer across the slot, are also described.
Turbulent buoyant convection from a source in a confined region
Authors: Manins P. C.
Published: April 2006

An extension of the model first proposed by Baines & Turner (1969) is derived with careful attention to the conditions required for its application. The most important of these are that the Prandtl number ν/kis of order unity or greater, the ratio of the lengthLto depthHof the region is greater than about 1·2 for the two-dimensional region considered andRis so large thatR[gsim ]L/HandR[Gt ] 1/α. The characteristic group\[ R\equiv \alpha^{\frac{2}{3}}F_0^{\frac{1}{3}}H/\nu. \]R2is a Grashof number based on the source strengthF0of the buoyant convection which is modelled using turbulent plume theory and the entrainment constant α, the ratio of inflow velocity across the edge of the plume to mean local plume velocity. The conditions onRensure that the source of buoyant convection is the dominant transportive mechanism in the region and the restrictions on the aspect ratio ensure that there is clear separation between the passive motions in the bulk of the region and the intense highly confined buoyant convection.

The manner in which the convective fluid recirculates to become part of the passive interior is studied and shown to be controlled by the same dynamics as fluid intrusion into a stably stratified environment.

Several new solutions are obtained, including cases of steady conditions involving only one source.
The distortion of turbulence by a circular cylinder
Authors: Britter R. E. , Hunt J. C. R. , Mumford J. C.
Published: April 2006

The flow of grid-generated turbulence past a circular cylinder is investigated using hot-wire anemometry over a Reynolds number range from 4·25 × 103 to 2·74 × 104 and a range of intensities from 0·025 to 0·062. Measurements of the mean velocity distribution, and r.m.s. intensities and spectral energy densities of the turbulent velocity fluctuations are presented for various radial and circumferential positions relative to the cylinder, and for ratios of the cylinder radius a to the scale of the incident turbulence Lx ranging from 0·05 to 1·42. The influence of upstream conditions on the flow in the cylinder wake and its associated induced velocity fluctuations is discussed.

For all measurements, detailed comparison is made with the theoretical predictions of Hunt (1973). We conclude the following.

The amplification and reduction of the three components of turbulence (which occur in different senses for the different components) can be explained qualitatively in terms of the distortion by the mean flow of the turbulent vorticity and the ‘blocking’ or ‘source’ effect caused by turbulence impinging on the cylinder surface. The relative importance of the first effect over the second increases as a/Lx increases or the distance from the cylinder surface increases.

Over certain ranges of the variables involved, the measurements are in quantitative agreement with the predictions of the asymptotic theory when a/Lx [Lt ] 1, a/Lx [Gt ] 1 or |k| a [Gt ] 1 (where k is the wavenumber).

The incident turbulence affects the gross properties of the flow in the cylinder wake, but the associated velocity fluctuations are probably statistically independent of those in the incident flow.

The dissipation of turbulent energy is greater in the straining flow near the cylinder than in the approach flow. Some estimates for this effect are proposed.
The low-shear limit of the effective viscosity of a solution of charged macromolecules
Authors: Russel William B.
Published: April 2006

The effect of pair interactions between charged macromolecules on the bulk stress is calculated for the Newtonian low-shear limit. Electrostatic force laws are derived for molecular conformations corresponding to the limits of weak and strong intramolecular repulsions and used to determine the equilibrium pair distribution function and the perturbation due to the flow. Intramolecular and near-field intermolecular hydrodynamic interactions are neglected as appropriate for so-called free draining macromolecules. The resulting bulk stress contains separate contributions from the far-field hydrodynamic interactions and the electrostatic forces. The coefficient of the O(c2) term in the viscosity which equals 0.4 in the purely hydrodynamic limit is predicted to increase dramatically with decreasing ionic strength for charged macromolecules in agreement with experimental data in the literature.
Higher-order theory of the Weissenberg effect
Authors: Yoo J. , Joseph D. D. , Beavers G. S.
Published: April 2006

The higher-order theory of the Weissenberg effect is developed as a perturbation of the state of rest. The perturbation is given in powers of the angular frequency Ω of the rod and the solution is carried out to O(Ω4). The perturbation induces a slow-motion expansion of the stress into Rivlin-Ericksen tensors in combinations which are completely characterized by five viscoelastic parameters. The effects of each of the material parameters may be computed separately and their overall effect by superposition. The values of the parameters may be determined by measurement of the torque, surface angular velocity and height of climb. Such measurements are reported here for several different sample fluids. Good agreement between the third-order theory and measured values of the velocity is reported. Secondary motions which appear at are computed using biorthogonal series. The analysis predicts the surprising fact that secondary motions run up the climbing bubble against gravity and intuition.
Experiments on an aerofoil at high angle of incidence in longitudinal oscillations
Authors: Maresca C. , Favier D. , Rebont J.
Published: April 2006

Details of flow visualization, aerodynamic forces and pitching moment, static pressure and skin friction measurements have been carried out on a symmetrical aerofoil at fixed angle of incidence in longitudinal oscillations parallel to the uniform airstream of a wind-tunnel.

This investigation shows weak unsteady effects at incidences below that of static stall. For higher incidences, strong unsteady effects appear and depend on the frequency and amplitude of the oscillations. The measurements indicate an overshoot of the instantaneous lift and drag which is explained by a strong vortex shedding process occurring during the dynamic stall encountered by the aerofoil in decelerated motion, as observed for profiles oscillating in pitch through stall. When the aerofoil is going forward in accelerated motion dynamic reattachment may be observed at very high incidence over a short part of the period of oscillation.

Dynamic stall and dynamic reattachment contribute to a favourable effect of unsteadiness on the mean lift coefficient, which increases as compared to the steady state one, and which is expressed through an empirical formula involving incidence, frequency and amplitude of oscillations. At given incidence, optimization of this feature is achieved by matching the frequency and the amplitude of oscillation, respectively with the frequency linked with the highest peak of energy in the wake, and with the distance between two consecutive vortices in the mean wake when modelled as a von Kármán's vortex street.
A high-order cnoidal wave theory
Authors: Fenton J. D.
Published: April 2006

A method is outlined by which high-order solutions are obtained for steadily progressing shallow water waves. It is shown that a suitable expansion parameter for these cnoidal wave solutions is the dimensionless wave height divided by the parameter m of the cn functions: this explicitly shows the limitation of the theory to waves in relatively shallow water. The corresponding deep water limitation for Stokes waves is analysed and a modified expansion parameter suggested.

Cnoidal wave solutions to fifth order are given so that a steady wave problem with known water depth, wave height and wave period or length may be solved to give expressions for the wave profile and fluid velocities, as well as integral quantities such as wave power and radiation stress. These series solutions seem to exhibit asymptotic behaviour such that there is no gain in including terms beyond fifth order. Results from the present theory are compared with exact numerical results and with experiment. It is concluded that the fifth-order cnoidal theory should be used in preference to fifth-order Stokes wave theory for wavelengths greater than eight times the water depth, when it gives quite accurate results.
On averaged equations for finite-amplitude water waves
Authors: Stiassnie M. , Peregrine D. H.
Published: April 2006

The wave-action conservation equation for water waves is always derived from a Lagrangian for irrotational flow. This is quite satisfactory if the whole flow-field (i.e. waves and background current) is irrotational, but is inadequate for a background current with a large-scale (vertical) vorticity, even if the flow has negligible vorticity on the local scale of a few wavelengths. A wave-action conservation equation is derived for this case and equations governing the flow and the waves are given in a simple form closely parallel to the irrotational flow equations.
Measurements of turbulence in a zero-mean-shear mixed layer
Authors: Mcdougall Trevor J.
Published: April 2006

This paper is concerned with laboratory measurements of turbulence in a mixed layer and through a density interface, in the absence of a mean flow. The present results confirm the conclusion of Hopfinger & Toly (1976) that the turbulence in a mixed layer is not significantly affected by the slow entrainment of fluid across the bounding density interface. In a homogeneous fluid the turbulence intensity is found to be surprisingly non-uniform, even two grid mesh distances away from the grid. Velocity measurements have also been taken through a density interface (at the entraining boundary of a mixed layer) and the turbulence here varies in a manner that bears some resemblance to the theory of Hunt & Graham (1978). These velocity measurements were taken with a laser-Doppler anemometer and they were made possible by a novel experimental technique which eliminates the refractive index variations which normally occur in a turbulent, density-stratified liquid flow.
The effect of temperature-induced variations in charge carrier mobility on a stationary electrohydrodynamic instability
Authors: Worraker W. J. , Richardson A. T.
Published: April 2006

An externally applied d.c. electric field is known to produce instability in a plane layer of dielectric liquid heated from above. The stationary linear instability of a unipolar charge injection equilibrium for which carrier mobility depends linearly on temperature is investigated. It is found that the sign of the temperature gradient in relation to the emitting electrode determines whether or not such instability can occur, and that two types of instability can be distinguished: (i) a space charge modified Bénard mode; and (ii) a thermally modified space charge mode. It is shown that the critical voltage is highly dependent upon the absolute value of mobility and its variation across the layer.
Experiments on the Weis-Fogh mechanism of lift generation by insects in hovering flight. Part 1. Dynamics of the ‘fling’
Authors: Maxworthy T.
Published: April 2006

From a series of experiments using simplified mechanical models we suggest certain minor modifications to the Weis-Fogh (1973)–Lighthill (1973) explanation of the so-called ‘clap and fling’ mechanism for the generation of large lift coefficients by insects in hovering flight. Of particular importance is the production and motion of a leading edge, separation vortex that accounts for virtually all of the circulation generated during the initial phase of the ‘fling’ process. The magnitude of this circulation is substantially larger than that calculated using inviscid theory. During the motion that subsequently separates the wings, the vorticity over each of them is convected and combined to become a tip vortex of uniform circulation spanning the space between them. This combined vortex moves downwards as a part of a ring, of large impulse, that is then continuously fed from quasi-steady separation bubbles that move with the wings as they continue to open at a large angle of attack. Such effects are able to account for the large lift forces generated by the insect.
Model studies of the closing behaviour of the aortic valve
Authors: Van Steenhoven A. A. , Van Dongen M. E. H.
Published: April 2006

The closing mechanism of the natural aortic valve is investigated experimentally in a two-dimensional analogue. The interaction between the sinus content and the aortic flow when the latter is decelerating is studied for different Strouhal numbers: for high Strouhal numbers the sinus content rotates virtually as a rigid mass around the centreline whereas for low Strouhal numbers, corresponding to the human situation, the cusp remains straight and slowly rotates around its point of attachment. Simple theoretical models based on the phenomena observed are proposed. Acceptable agreement between theory and experiment is found.
Peristaltic transport due to finite amplitude bending and contraction waves
Authors: Wilson Dennis E. , Panton Ronald L.
Published: April 2006

This analysis demonstrates theoretically that a lateral bending wave propagating along the walls of a two-dimensional channel filled with a viscous incompressible fluid will induce a mean flow. In addition to this ‘pure’ bending wave, another possible condition is investigated: that of the superposition of an area contraction wave propagating with the same speed as the lateral bending wave. This second condition, called complex wave motion, takes into account the slight occlusion which occurs naturally at the amplitude peaks when a finite amplitude bending wave propagates along the walls of a container. A perturbation solution is found which satisfies Navier—Stokes equations for the case in which wave amplitude/wavelength is ‘small’. However the wave amplitude is finite, in the sense that it is of the same order as the channel width. Under these conditions, the occlusion at the amplitude peaks is allowed to be of the same order as the channel width. For the case of a pure bending wave the motion induced by the peristaltis is found to be of second order in the perturbation parameter, whereas in the more realistic case a first-order pumping effect is obtained.
Third-order approximation to short-crested waves
Authors: Hsu J. R. C. , Tsuchiya Y. , Silvester R.
Published: April 2006

Short-crested wave systems, as produced by two progressive waves propagating at an oblique angle to each other, have an extremely important effect on a sedimentary bed. The complex water-particle motions are conducive to lifting material into suspension and sustaining it in motion. In order to study this phenomenon rigorously, the variables of this wave system are derived to a third-order approximation by a perturbation method. The case of waves reflecting obliquely from a vertical wall is examined under the assumptions of full reflexion, uniform finite depth and an inviscid incompressible fluid. The new formulation reduces to standing or Stokes waves at the limiting angles of approach. Expressions for kinematic quantities are also presented.
Laminar boundary-layer reattachment in supersonic flow
Authors: Daniels P. G.
Published: April 2006

A rational theory is developed to describe the reattachment of a laminar shear layer in supersonic flow. In the neighbourhood of reattachment the flow develops a threetiered or ‘triple-deck’ structure analogous to that which occurs at a point of separation (Stewartson & Williams 1969) and, as in the separation problem, the local flow pattern may be found independently of the flow in the surrounding regions. The fundamental problem of the reattachment triple deck reduces to the solution of the incompressible boundary-layer equations in the lower deck, which is of streamwise and lateral dimensions O(R−⅜) and O(R−⅝), where R [Gt ] 1 is a representative Reynolds number for the flow. Pressure variations in this region are O(R−¼). Asymptotic solutions in terms of x, the scaled streamwise lower-deck variable, are derived to confirm the transition from a reverse flow profile at x = 0+, through reattachment, to a forward flow as x → ∞, the attainment of the required asymptotic form downstream (as x → ∞) being shown to depend crucially upon the correct choice of the finite part of the pressure in the lower deck at x = 0+. The lower-deck solution is singular at x = 0+ and assumes a complicated multi-structured form which is shown to match upstream with the solution in a largely inviscid region of dimension O(R−½) where the pressure is O(1) and the major part of the flow reversal takes place. Solutions are presented for reattachment at a wall and for symmetric reattachment behind a wedge or bluff body. In the former case the results also explain the apparent ignorance of upstream conditions in the expansive triple-deck solution formulated by Stewartson (1970) in the context of supersonic flow around a convex corner.
A note on the rate of heat or mass transfer from a small particle freely suspended in a linear shear field
Authors: Acrivos Andreas
Published: April 2006

It is shown that for a small sphere freely suspended in a linear shear flow at small Reynolds numbers, the Nusselt number N is given by $N = \{1 - \alpha P^{\frac{1}{2}} + o(P^{\frac{3}{2}})\}^{-1}$, where P is the Péclet number. For any given type of shear flow, the numerical value of the constant α can be obtained from a general expression derived by Batchelor (1979). The corresponding result for a particle of arbitrary shape is N/N0 = {1 − αN0P½ + O(P3/2)}−1, where N0 is the Nusselt number for pure conduction.
Shelves and the Korteweg-de Vries equation
Authors: Knickerbocker C. J. , Newell Alan C.
Published: April 2006

An extension of the analytical results of Kaup & Newell (1978) concerning the effect of a perturbation on a solitary wave of the Korteweg–de Vries equation is given and numerical studies are conducted to verify the conclusions. In all cases, the numerical results agree with the results predicted by the theory. The most striking feature of the perturbed flow is the presence of a shelf in the lee of the solitary wave whose role is to absorb (provide) the extra mass which is created (depleted) by the perturbation.
Velocity measurements inside a rotating cylindrical cavity with a radial outflow of fluid
Authors: Owen J. M. , Pincombe J. R.
Published: April 2006

Flow visualization and laser-doppler anemometry have been used to determine the flow structure and measure the velocity distribution inside a rotating cylindrical cavity with an outer to inner radius ratio of 10, and an axial spacing to inner radius ratio of 2·67. A flow structure comprising an inner layer, Ekman layers, an outer layer and an interior potential core has been confirmed for the cases where the inlet air enters the cavity either axially, through a central hole, or radially, through a central gauze tube, and leaves radially through a series of holes in the peripheral shroud. Velocity measurements in the laminar Ekman layers agree well with the ‘modified linear theory’, and long-and short-wavelength disturbances (which have been reported by other experimenters) have been observed on the Ekman layers when the radial Reynolds number exceeds a critical value. The phenomenon of reverse flow in the Ekman layers and the possibility of ingress of external fluid through the holes in the shroud have also been observed.
Techniques of sizing and tracking of particles: A report on Euromech 120
Authors: Larsen P. S. , Engelund F. , Sumer B. M. , Lading L.
Published: April 2006

The 120th Euromech Colloquium on experimental techniques pertaining to sizing and tracking of submicron- to millimetre-sized particles suspended in fluids was held at Lyngby on 20–22 August 1979 with forty-one participants from ten countries. Twenty-seven papers were presented during the two-and-a-half day meeting. Techniques included optical and acoustical sizing and velocity measurements, tracking, sedimentation and deposition of particles in various gas and liquid flows.
On the behaviour of the laminar boundary-layer equations of mixed convection near a point of zero skin friction
Authors: Hunt Roland , Wilks Graham
Published: April 2006

The boundary-layer equations of mixed convection are examined in the vicinity of separation. The correlation between the uniform wall temperature case and that of compressible boundary layer flow is outlined. Goldstein–Stewartson–Buckmaster theory is thus appropriate and associated indeterminacies in the theory are evaluated from a numerical integration. The case of uniform heat flux at the wall is then examined theoretically. Significantly it is concluded that the original Goldstein–Stewartson theory is sufficient to describe the structure of the singularity at separation in this case. Indeterminacies associated with the theory are determined via a reconciliation between analytical and numerical representation of skin friction and heat transfer coefficients near separation.
Vortex pairing in a circular jet under controlled excitation. Part 1. General jet response
Authors: Zaman K. B. M. Q. , Hussain A. K. M. F.
Published: April 2006

Hot-wire and flow-visualization studies have been carried out in three air jets subjected to pure-tone acoustic excitation, and the instability, vortex roll-up and transition as well as jet response to the controlled excitation have been investigated. The centreline fluctuation intensity can be enhanced by inducing stable vortex pairing to a level much higher than even that at the ‘preferred mode’, but can also be suppressed below the unexcited level under certain conditions of excitation. The conditions most favourable to vortex pairing were determined as a function of the excitation Strouhal number, the Reynolds number (ReD), and the initial shear-layer state, i.e. laminar or turbulent. It is shown that the rolled-up vortex rings undergo pairing under two distinct conditions of excitation: ‘the shear layer mode’ when the Strouhal number based on the initial shear-layer momentum thickness (Stθ) is about 0·012, and ‘the jet column mode’ when the Strouhal number based on the jet diameter (StD) is about 0·85. The former involves pairing of the near-exit thin vortex rings when the initial boundary layer is laminar, irrespective of the value of StD. The latter involves pairing of the thick vortex rings at x/D ≅ 1·75, irrespective of Stθ or whether the initial boundary layer is laminar or turbulent. For laminar exit boundary layer, pairing is found to be stable, i.e., occurring regularly in space and time, for ReD < 5 × 104, but becomes intermittent with increasing ReD or fluctuation intensity in the initial boundary layer.

The trajectories of the vortex centres and their convection velocities during a pairing event have been recorded through phase-locked measurements. In the presence of stable vortex pairing, the time average profiles of fluctuation intensities and Reynolds stress show noticeable deviations from those in the unexcited jet. The vortex pairing phenomenon produce considerably larger excursions of the $\widetilde{uv}(t)$ signal than the time-average Reynolds stress reveals, suggesting that only certain phases of the pairing process may be important in entrainment, and production of Reynolds stress and jet noise.
Visualization of actin cytoskeletal dynamics during the cell cycle in tobacco (Nicotiana tabacum L. cv Bright Yellow) cells
Authors: Yu Miaomiao , Yuan Ming , Ren Haiyun
Published: April 2006

Background information. The actin cytoskeleton forms distinct actin arrays which fulfil their functions during cell cycle progression. Reorganization of the actin cytoskeleton occurs during transition from one actin array to another. Although actin arrays have been well described during cell cycle progression, the dynamic organization of the actin cytoskeleton during actin array transition remains to be dissected.

Results. In the present study, a GFP (green fluorescent protein)‐mTalin (mouse talin) fusion gene was introduced into suspension‐cultured tobacco BY‐2 (Nicotiana tabacum L. cv Bright Yellow) cells by a calli‐cocultivation transformation method to visualize the reorganization of the actin cytoskeleton in vivo during the progression of the cell cycle. Typical actin structures were indicated by GFP—mTalin, such as the pre‐prophase actin band, mitotic spindle actin filament cage and phragmoplast actin arrays. In addition, dynamic organization of actin filaments was observed during the progression of the cell from metaphase to anaphase. In late metaphase, spindle actin filaments gradually shrank to the equatorial plane along both the long and short axes. Soon after the separation of sister chromosomes, actin filaments aligned in parallel at the cell division plane, forming a cylinder‐like structure. During the formation of the cell plate, one cylinder‐like structure changed into two cylinder‐like structures: the typical actin arrays of the phragmoplast. However, the two actin arrays remained overlapping at the margin of the centrally growing cell plate, forming an actin wreath. When the cell plate matured further, an actin filament network attached to the cell plate was formed.

Conclusions. Our results clearly describe the dynamic organization of the actin cytoskeleton during mitosis and cytokinesis of a plant cell. This demonstrates that GFP—mTalin‐transformed tobacco BY‐2 cells are a valuable tool to study actin cytoskeleton functions in the plant cell cycle.
Intracellular degradation of insulin and crinophagy are maintained by nitric oxide and cyclo‐oxygenase 2 activity in isolated pancreatic islets
Authors: Sandberg Monica , Borg L.A. Håkan
Published: April 2006

Background information. Pancreatic β‐cells require an optimal insulin content to allow instantaneous secretion of insulin. This is maintained by insulin biosynthesis and intracellular degradation of insulin. Degradation may be effected by crinophagy, i.e. the fusion of secretory granules with lysosomes. IL‐1β (interleukin 1β) induces distinct changes of β‐cell lysosomes. To study the mechanisms for intracellular insulin degradation and crinophagy, isolated mouse pancreatic islets were exposed to IL‐1β and known pathways for IL‐1β actions were blocked. Intracellular insulin degradation was determined by following the fate of radioactively labelled insulin. Crinophagy was studied by ultrastructural analysis. The effects of blocking pathways for IL‐1β were monitored by measurements of nitrite and PGE2 (prostaglandin E2).

Results. IL‐1β caused an enhancement of islet intracellular insulin degradation and an increase in the lysosomal incorporation of β‐cell secretory granules. The effects of IL‐1β were abolished by aminoguanidine, a selective inhibitor of inducible NOS (nitric oxide synthase), or by rofecoxib, a specific inhibitor of COX‐2 (cyclo‐oxygenase 2). In the absence of IL‐1β, nitroarginine, which is a selective inhibitor of constitutive NOS, caused a decrease in intracellular degradation of insulin in parallel with a decreased production of NO and PGE2 by the islets.

Conclusions. The correlation between the enhanced intracellular insulin degradation and lysosomal changes caused by IL‐1β suggests that insulin degradation may be effected by crinophagy. Under physiological conditions, significant β‐cell degradation of insulin may depend on the activity of COX‐2, possibly stimulated by endogenous NO.
Possible performance improvement in [2]catenane molecular electronic switches
Authors: Kim Yong-Hoon , Jang Seung Soon , Goddard William A.
Published: April 2006

Mechanically interlocked bistable supramolecular complexes are promising candidates of molecular electronics. Applying a multiscale computational approach, here we study the coherent charge transport properties of catenane monolayers sandwiched between Cu(111) electrodes. We demonstrate the robust nature of electrical switching behavior with respect to the variations in the monolayer packing density and the type of electrodes, as well as the thermal fluctuations of the molecules. We propose that the asymmetry of molecule-electrode barriers can be utilized to improve the switching ratio.
Angioma serpiginosum: Dermoscopy for diagnosis, pulsed dye laser for treatment
Authors: İLKNUR Turna , FETIL Emel , AKARSU Sevgi , ALTINER Didem Didar , ULUKUŞ Çağnur , GÜNEŞ Ali Tahsin
Published: April 2006

Angioma serpiginosum is a rare benign vascular disorder, characterized clinically by multiple minute, red to purple, grouped macules in serpiginous and gyrate patterns and histopathologically by ectatic dilatation of capillaries. Patients can undergo unnecessary hematological tests, because the condition can be confused with chronic purpuric dermatoses. An 18‐year‐old man with angioma serpiginosum of his left arm was evaluated by dermoscopy and treated with pulsed dye laser. Numerous small, relatively well‐demarcated, round to oval red lagoons were determined with dermoscopy, and approximately 75% of the area of his lesion disappeared after four sessions of pulsed dye laser. Our case supports the hypothesis that dermoscopy is beneficial in the diagnosis of angioma serpiginosum and that pulsed dye laser is effective in the treatment of this disorder.
Effect of Bacillus licheniformis and Bacillus subtilis Supplementation of Ewe's Feed on Sheep Milk Production and Young Lamb Mortality
Authors: Kritas S. K. , Govaris A. , Christodoulopoulos G. , Burriel A. R.
Published: April 2006

The purpose of this pilot study was to evaluate under field conditions the effect of a probiotic containing Bacillus licheniformis and Bacillus subtilis on young lamb mortality and sheep milk production when administered in the late pregnancy and lactation feed of ewes. In a sheep farm, two groups of milking ewes with identical genetic material, management, nutrition, health status and similar production characteristics were formed. One group (46 ewes) served as control, while the other one (48 ewes) served as a probiotic‐treated group. Both groups of ewes received a similar feeding regiment, but the ewes of the second group were additionally offered a probiotic product containing B. licheniformis and B. subtilis (BioPlus 2B, Chr. Hansen, Denmark) at the approximate dose of 2.56 × 109 viable spores per ewe per day. Lamb mortality during the 1.5 months suckling period, and milk yield during the 2 months of milk collection for commercial purposes have been recorded. In the non‐treated control group, 13.1% mortality was observed versus 7.8% in the probiotic‐treated group (P = 0.33), with mortality being mainly due to diarrhoea. Microbiological examination of diarrhoeic faeces from some of the dead lambs in both groups revealed the presence of Escherichia coli. The average daily milk yield per ewe was significantly lower in the control group (0.80 l) than that in the probiotic‐treated group (0.93 l) (P < 0.05). Fat and protein content of milk in ewes that received probiotics was significantly (P < 0.05) increased compared with untreated ewes. It was concluded that supplementing ewe's feed with probiotics may have beneficial effect on subsequent milk yields, fat and protein content.
On paternalism, autonomy and best interests: Telling the (competent) aged‐care resident what they want to know
Authors: Tuckett Anthony G
Published: April 2006

This paper has been derived from a review of literature from a recent qualitative study that explored the meaning of truth‐telling within the care provider–aged resident dyad in high‐level (nursing home) care of elderly people. In the literature reviewed here, paternalism (as benevolent decision‐making in another's best interests) is critically analysed. Autonomy is then described and its function in promoting health is underscored. Furthermore, this paper specifically challenges nurses to consider their capacity to really know another's best interests—particularly in the nursing home. Finally, a very simple recommendation is proposed for determining and managing the (competent) aged‐care resident's informational disclosure preferences: ask them.
Chlorophyll fluorescence technique as a rapid diagnostic test of the effects of the photosynthetic inhibitor chlorotoluron on two winter wheat cultivars
Authors: KORRES N E , FROUD‐WILLIAMS R J , MOSS S R
Published: April 2006

A modified chlorophyll fluorescence technique was evaluated as a rapid diagnostic test of the susceptibility of wheat cultivars to chlorotoluron. Two winter wheat cultivars (Maris Huntsman and Mercia) exhibited differential response to the herbicide. All of the parameters of chlorophyll fluorescence examined were strongly influenced by herbicide concentration. Additionally, the procedure adopted here for the examination of winter wheat cultivar sensitivity to herbicide indicated that the area above the fluorescence induction curve and the ratio FV/FM are appropriate chlorophyll fluorescence parameters for detection of differential herbicide response between wheat cultivars. The potential use of this technique as an alternative to traditional methods of screening new winter wheat cultivars for their response to photosynthetic inhibitor herbicide is demonstrated here.
STABILITY OF ABELIAN COMPLEX STRUCTURES
Authors: CONSOLE S. , FINO A. , POON Y. S.
Published: April 2006

Let M = Γ\G be a nilmanifold endowed with an invariant complex structure. We prove that Kuranishi deformations of abelian complex structures are all invariant complex structures, generalizing a result in [7] for 2-step nilmanifolds. We characterize small deformations that remain abelian. As an application, we observe that at real dimension six, the deformation process of abelian complex structures is stable within the class of nilpotent complex structures. We give an example to show that this property does not hold in higher dimension.
ANALYSIS OF PARABOLIC PROBLEMS ON PARTITIONED DOMAINS WITH NONLINEAR CONDITIONS AT THE INTERFACE: APPLICATION TO MASS TRANSFER THROUGH SEMI-PERMEABLE MEMBRANES
Authors: CALABRÒ FRANCESCO , ZUNINO PAOLO
Published: April 2006

In this work we address a problem governed by linear parabolic partial differential equations set in two adjoining domains, coupled by nonlinear interface conditions of Neumann type. In particular, we address the existence and uniqueness of strong solutions by applying the strong maximum principle, the Schauder fixed point theorem and the fundamental solutions of linear parabolic partial differential equations.

In the first part of this work, we consider the properties of a linear parabolic partial differential equation set on a single domain with a nonlinear boundary condition. After having addressed the well-posedness and some comparison results for the problem on one domain, in the second part of this work we address the case of coupled problems on adjoining domains. In both cases, we complete the understanding of the behavior of the solution of the problems at hand by means of numerical simulations.

The theoretical results obtained here are applied to study the behavior of a biological model for the transfer of chemicals through thin biological membranes. This model represents the dynamics of the concentration u of a chemical solution separated from the exterior by a semi-permeable membrane.

The analysis of the two-domain problem that we carry out could also be used to investigate the convergence property of iterative substructuring methods applied to the approximation of multidomain problems with nonlinear coupling of Neumann type.
QUASINEUTRAL LIMIT OF THE MULTI-DIMENSIONAL DRIFT-DIFFUSION-POISSON MODELS FOR SEMICONDUCTORS WITH PN-JUNCTIONS
Authors: WANG SHU
Published: April 2006

In this paper the vanishing Debye length limit (space charge neutral limit) of bipolar time-dependent drift-diffusion models for semiconductors with p-n-junctions (i.e. with a fixed bipolar background charge) is studied in the multi-dimensional case. For generally smooth sign-changing doping profiles with good boundary conditions, the quasineutral limit (zero-Debye-length limit) is justified rigorously in the Sobolev's norm uniformly in time. The proof is based on the elaborate energy method and the relative entropy functional method which yields the uniform estimates with respect to the scaled Debye length.
WELL-POSEDNESS OF A PHASE TRANSITION MODEL WITH THE POSSIBILITY OF VOIDS
Authors: FRÉMOND MICHEL , ROCCA ELISABETTA
Published: April 2006

The paper deals with a phase transition model applied to a two-phase system. There is a wide literature on the study of phase transition processes in case that no voids nor overlapping can occur between the two phases. The main novelty of our approach is the possibility of having voids during the phase change. This aspect is described in the model by the mass balance equation whose effects are included by means of the pressure of the system in the dynamical relations. The state variables are the absolute temperature (whose evolution is ruled by the entropy balance equation), the strain tensor (satisfying a quasi-static macroscopic equation of motion), and the volume fractions of the two phases (whose evolutions are described by a vectorial equation coming from the principle of virtual power and related to the microscopic motions). Well-posedness of the initial-boundary value problem associated to the PDEs system resulting from this model is proved.
Cortisol stimulates system A amino acid transport and SNAT2 expression in a human placental cell line (BeWo)
Authors: Jones Helen N. , Ashworth Cheryl J. , Page Ken R. , McArdle Harry J.
Published: April 2006

Both placental system A activity and fetal plasma cortisol concentrations are associated with intrauterine growth retardation, but it is not known if these factors are mechanistically related. Previous functional studies using hepatoma cells and fibroblasts produced conflicting results regarding the regulation of system A by cortisol. Using the b30 BeWo choriocarcinoma cell line, we investigated the regulation of system A by cortisol. System A function was analyzed using methyl amino isobutyric acid (MeAIB) transcellular transport studies. Transporter expression [system A transporter (SNAT)1/2] was studied at the mRNA and protein levels using Northern and Western blotting, respectively. Localization was carried out using immunocytochemistry. The [14C]MeAIB transfer rate across BeWo monolayers after preincubation with cortisol for 24 h was significantly increased compared with control. This was associated with a relocalization of the SNAT2 transporter at lower cortisol levels and significant upregulation of mRNA and protein expression levels at cortisol levels >1 μM. This is the first study to show functional and molecular regulation of system A by cortisol in BeWo cells. It is also the first study to identify which system A isoform is regulated. These results suggest that cortisol may be involved in upregulation of system A in the placenta to ensure sufficient amino acid supply to the developing fetus.
Nursing in Hong Kong: Issues and Challenges
Authors: Thompson David R.
Published: April 2006

This column provides a discussion of the issues and challenges facing nurses and nursing in Hong Kong. The author introduces the role of nurses in the special administrative region and focuses on workforce, educational and practice issues, as well as on leadership in nursing. He concludes that Hong Kong needs to have a strategic plan to determine sufficient numbers of properly educated nurses.
Personal Web Home Pages of Adolescents With Cancer: Self-Presentation, Information Dissemination, and Interpersonal Connection
Authors: Suzuki Lalita K. , Beale Ivan L.
Published: April 2006

The content of personal Web home pages created by adolescents with cancer is a new source of information about this population of potential benefit to oncology nurses and psychologists. Individual Internet elements found on 21 home pages created by youths with cancer (14-22 years old) were rated for cancer-related selfpresentation, information dissemination, and interpersonal connection. Examples of adolescents' online narratives were also recorded. Adolescents with cancer used various Internet elements on their home pages for cancer-related self-presentation (eg, welcome messages, essays, personal history and diary pages, news articles, and poetry), information dissemination (e.g., through personal interest pages, multimedia presentations, lists, charts, and hyperlinks), and interpersonal connection (eg, guestbook entries). Results suggest that various elements found on personal home pages are being used by a limited number of young patients with cancer for self-expression, information access, and contact with peers.
In-tandem insight from basic science combined with clinical research: CD38 as both marker and key component of the pathogenetic network underlying chronic lymphocytic leukemia
Authors: Deaglio Silvia , Vaisitti Tiziana , Aydin Semra , Ferrero Enza , Malavasi Fabio
Published: April 2006

The absence of mutations in the IgV genes, together with the presence of ZAP-70 and CD38, are the most reliable negative prognostic markers for chronic lymphocytic leukemia (CLL) patients. Several lines of evidence indicate that CD38 may be not only a diagnostic marker but also a key element in the pathogenetic network in CLL. First, CD38 is a receptor that induces proliferation and increases survival of CLL cells. Second, CD38 signals start upon interaction with the CD31 ligand expressed by stromal and nurse-like cells. Third, CD38/CD31 contacts up-regulate CD100, a semaphorin involved in sustaining CLL growth. Fourth, evidence that nurselike cells express high levels of CD31 and plexin-B1, the high-affinity ligand for CD100, offers indirect confirmation for this model of receptor cross-talk. Elements of variation in the clinical course of CD38+ CLL patients include (1) potential intersection with ZAP-70, a kinase involved in the CD38 signaling pathway in T and natural killer (NK) cells, and (2) the effects of genetic polymorphisms of the receptors involved, at least of CD38 and CD31. Consequently, CD38 together with ZAP-70 appear to be the key elements of a coreceptor pathway that may sustain the signals mediated by the B-cell receptor and potentially by chemokines and their receptors. This would result in acquisition of increased survival potential, providing clues to the poorer prognosis of CD38+ patients.