bluuebunny/crossref_metadata_2025 huggingface dataset:
Dosing and Timing Effects of Anti‐CD40L Therapy
Authors: GADKAR KAPIL G. , SHODA LISL K. M. , KREUWEL HUUB T. C. , RAMANUJAN SAROJA , ZHENG YANAN , WHITING CHAN C. , YOUNG DANIEL L.
Published: May 2007

Abstract:  Several publications describing the use of anti‐CD40L monoclonal antibodies (anti‐CD40L) for the treatment of type 1 diabetes in non‐obese diabetic (NOD) mice have reported different treatment responses to similar protocols. The Entelos® Type 1 Diabetes PhysioLab® platform, a dynamic large‐scale mathematical model of the pathogenesis of type 1 diabetes, was used to study the effects of anti‐CD40L therapy in silico. An examination of the impact of pharmacokinetic variability and the heterogeneity of disease progression rate on therapeutic outcome provided insights that could reconcile the apparently conflicting data. Optimal treatment protocols were identified by exploring the dynamics of key pathophysiological pathways.
Are Insights Gained from NOD Mice Sufficient to Guide Clinical Translation?
Authors: ROEP BART O.
Published: May 2007

Abstract:  Despite decades of research using various animal models for type 1 diabetes, we are still struggling to define the initiating autoantigens, the precise mechanisms of β cell destruction, and suitable immune‐based interventions to prevent or treat human diabetes. Animal models, such as the non‐obese diabetic (NOD) mouse and the biobreeding (BB) rat, develop immune‐mediated diseases with features resembling type 1 diabetes in humans. Although these animal models of autoimmune diabetes have proved to be valuable tools to study certain aspects of the disease process, they have also led to misconceptions and erroneous extrapolations, as well as false expectations with regard to the efficacy of immunotherapy. It is therefore time to ask ourselves whether we are making major strategic mistakes when employing rodent models for the study of type 1 diabetes. This review will describe where rodent models have provided us with proper guidance and where they have misled us, concluding that each model only offers partial information with undefined clinical value. Therefore, a more critical attitude and repetition of crucial observations in different model settings will be necessary in the future. I will argue that animal models have limited but evident value when it comes to teaching us about type 1 diabetes in humans, and we can take advantage of this value more efficiently.
Refinement of the Iddm4 Diabetes Susceptibility Locus Reveals TCRVβ4 as a Candidate Gene
Authors: BLANKENHORN ELIZABETH P. , DESCIPIO CHERYL , RODEMICH LUCY , CORT LAURA , LEIF JEAN H. , GREINER DALE L. , MORDES JOHN P.
Published: May 2007

Abstract: 
Iddm4 is a dominant non‐major histocompatibility complex (MHC) determinant of diabetes susceptibility in BBDR rats treated with poly I:C, plus depletion of regulatory T cells. In congenic MHC‐identical normal WF rats, Iddm4d sensitively and specifically predicts induced diabetes. We report a new diabetes‐susceptible subcongenic line that carries Iddm4 in a < 2.6 megabase interval. Candidate genes include the T cell receptor β chain variable (TCRVβ) family. We found that TCRVβ4 in WF rats contains a stop codon, whereas 5/5 diabetes‐susceptible rat strains express TCRVβ4. We conclude that Iddm4‐mediated diabetes resistance in rats may be due to a recessive protective mutation in TCRVβ4.
Antigen Presentation in the CNS by Myeloid Dendritic Cells Drives Progression of Relapsing Experimental Autoimmune Encephalomyelitis
Authors: MILLER STEPHEN D. , McMAHON EILEEN J. , SCHREINER BETTINA , BAILEY SAMANTHA L.
Published: May 2007

Abstract:  Chronic progression of relapsing experimental autoimmune encephalomyelitis (R‐EAE), a mouse model of multiple sclerosis (MS), is dependent on the activation of T cells to endogenous myelin epitopes, that is, epitope spreading. This review focuses on the cellular and molecular mechanisms underlying the process of epitope spreading. Surprisingly, activation of naïve T cells to endogenous myelin epitopes in SJL mice undergoing R‐EAE occurs directly in the central nervous system (CNS), a site generally perceived to be immunologically privileged. Determination of the antigen presentation capacity of antigen‐presenting cell (APC) populations purified from the CNS of mice with established R‐EAE shows that peripherally derived CD11b+CD11c+CD45hi myeloid dendritic cells (mDCs) most efficiently present endogenous myelin antigens to activate both preactivated effector myelin‐specific T cells and naïve T cells. The mDCs, which drive epitope spreading, preferentially polarize pathogenic Th17 responses correlating with their enhanced expression of TGF‐β1, IL‐6, and IL‐23. Both B220+CD11c+ plasmacytoid (pDCs) and CD8α+CD11c+ (CD8 DCs) were superior to CD11b+CD11c–CD45hi macrophages, but less efficient than mDCs at presenting endogenous peptide to induce Th17 cells. In contrast, CNS‐resident CD11b+CD11c–CD45low microglia purified from the inflamed CNS were found to be largely incapable of activating either naïve or effector T cells.
Addressing the Security Issue in the Middle East: The Importance of Interrelationship and Inclusion
Authors: Bakoyannis Dora
Published: May 2007

Dora Bakoyannis is foreign minister of Greece. This essay is adapted from a speech at the international conference “Solving the Security Puzzle in the Mediterranean and the Broader Middle East,” held in Athens on 24 November 2006.
Italy and the Greater Middle East: A Need for Resolute Patience
Authors: D'Alema Massimo
Published: May 2007

Massimo D'Alema is deputy prime minister and foreign minister of Italy. This article draws on a speech Minister D'Alema gave at the Aspen Institute Italia, Rome, 1 October 2006.
Sudan and the National Congress Party
Authors: Winter Roger P.
Published: May 2007

Roger P. Winter is former assistant administrator for the Bureau for Democracy, Conflict, and Humanitarian Assistance of the US Agency for International Development and former special representative of the US deputy secretary of state for Sudan.
Motion-curve synthesis and geometric design of globoidal cam mechanism with intermittent variable speed
Authors: Lin B J , Lin C C , Jywe W Y , Lin S Y , Lin J C
Published: May 2007

A design procedure for increasing the performance of an intermittent globoidal cam mechanism is presented. The proposed procedure is based on the synthesis of roller-follower turret motions at two different speeds to lower the inertia effect caused by the start/stop behaviour of the intermittent mechanism. The motion curves in a globoidal cam mechanism with an intermittent variable speed are defined by non-parametric rational B-splines to increase the transport capability. There are four key techniques to design a cam mechanism: the first is to construct the cam profile by using the volume swept method, the second is to synthesize the motion curve of a turret by using a rational B-spline curve on velocity control, the third is to analyse the mechanical properties of cam by using the geometrical vector method, and the last is to plan an NC programme and to estimate the performance of five-axial precision machining. Four types of motion curves with similar geometric properties are used and the rational B-spline has better dynamic properties than the other three curves. The systematic design approach proposed for a globoidal cam mechanism with an intermittent variable speed is to improve its performance, to upgrade effectively the function of the indexing device, and to increase the production speed of industrial automatic conveyance.
Optimal design of a compliant mechanism with circular notch flexure hinges
Authors: Choi K-B , Han C S
Published: May 2007

This paper presents an optimal design of a compliant mechanism with circular notch flexure hinges as well as a performance evaluation of a two-axes ultra-precision stage using the compliant mechanism. The compliant mechanism consists of two double-symmetric four-link mechanisms for two translational motions. As the circular notch flexure hinge can produce rotation as well as axial translation via its deformation, the double symmetric four-link mechanism can translate along one direction in a small range. In the optimal design, a composite global design index based on Min-Max principle is applied for the design of the compliant mechanism with circular notch flexure hinges owing to its simplicity and compactness. The designed compliant mechanism, piezoelectric elements for actuation, and capacitance-type displacement sensors for position measurement are assembled into an ultra-precision stage. The experimental results show that the stage implemented by the compliant mechanism will be applicable to two-axes ultra-precision positioning systems such as the fine positioning table of coarse-fine positioning systems, ultra-precision machining centres, wafer stages, and scanners for atomic force microscopy (AFM).
Numerical study for the impact of liquid droplets on solid surfaces
Authors: Yang A-S , Yang M-T , Hong M-C
Published: May 2007

The impinging behaviour of liquid droplets on solid surfaces is studied using a computational approach. The analysis comprises the unsteady three-dimensional conservation equations of mass and momentum, with the surface tension effect treated by the continuous surface force model. Gas-liquid interfacial motions are simulated by the volume-of-fluid method in conjunction with the piecewise linear interface construction technique. In the computer code validation for a water droplet impacting on a polished stainless steel surface, computer-generated images of the time evolution of the droplet impingement dispersal shape are compared with magnified photographs by Pasandideh-Fard et al. The flow and transport phenomena in the impingement flowfield are further examined in detail. In order to respond to the need for its use in practical applications, the study is extended to explore the spreading progression to achieve a better understanding of the interaction of a 30 μm diameter polyethylenedioxy thiophene liquid droplet with a 50 × 50 μm indium tin oxide-coating square cavity at an impact velocity of 6 m/s.
Human tactile perception of screen-printed surfaces: Self-report and contact mechanics experiments
Authors: Childs T. H. C. , Henson B
Published: May 2007

Polyester sheets were screen-printed with 16 different patterns formed from one of two different types of polymer-based ink. The patterns were arrays of bumps or pockets with different pitch and per cent coverage of ink. People stroked their fingers over the sheets and reported their resulting feelings in terms of 15 prechosen word pairs, ranging from the psycho-physical smooth-coarse to the more impressionable or affective artificial-natural and happy-sad. It has been possible partially to relate feelings to the printed surfaces' roughnesses and sliding friction coefficients against a fingertip. But the measure of roughness is resolvability of the bumps or pockets by a fingertip and that of friction coefficient is maximum value of the coefficient, on surfaces of mixed materials that showed different coefficients for each material. However, because not all aspects of the results have been explained, these conclusions are tentative. Apparent and real contact areas were observed between both static and sliding fingertips and smooth and printed surfaces. Simple contact and sliding friction models were introduced to explain observed friction coefficients between a sliding fingertip and the printed surfaces and, from comparison with experiments, to derive fingertip skin elastic moduli for future contact mechanics simulations. These moduli are so highly dependent on assumed skin thickness that it is argued that calibration of simulations against experiment will always be essential. A simple test is proposed.
Elastohydrodynamic modelling of heat partition in rolling-sliding point contacts
Authors: Clarke A , Sharif K. J. , Evans H. P. , Snidle R. W.
Published: May 2007

This article presents the results of a series of thermal elastohydrodynamic lubrication (EHL) analyses of a set of disc experiments carried out by Patching et al. The authors have previously calculated the heat partition at each load stage fromthe experimental data, and the present work seeks to compare the heat partition developed in a thermal EHL analysis of the lubricant film with that calculated from the experiments. These EHL analyses show that the heat partition depends on the non-Newtonian formulation used. Only when the dissipation takes place by wall slip occurring at the faster moving surface do the heat partition results approach those determined from the experimental results. It is concluded that this combination of experimental heat partition results with associated EHL analysis can prove to be a much more discerning test of rheological behaviour in EHL contacts than is provided by measurement of traction.
Variable lubricant supply of a starved hydrodynamic linear contact: Lubricant lateral flow for smooth and laser textured surfaces
Authors: Organisciak M , Cavallaro G , Lubrecht A. A.
Published: May 2007

This article presents the study of a starved hydrodynamic linear contact with a variable lubricant inlet layer. Variable lubricant films are likely to occur in piston rings-cylinder liner contacts. The lubricant layer is assumed to have a sinusoidal shape with a defined wavelength in the direction perpendicular to the direction of movement. The contact is modelled in pure rolling. Two equally large zones can be defined: a severely starved central zone, around the minimum of the sine function, and a lightly starved zone, around the maxima of the sine function. This kind of inlet lubricant distribution affects the pressure and the lubricant distribution: after a passage, a part of the lubricant present in the lightly starved zone is transferred to the severely starved zone. An efficiency parameter ER of the lubricant reflow is defined. First, the results show the evolution of the lubricant reflow as a function of the operating conditions, i.e. speed, load and lubricant film thickness, and the wavelength of the lubricant distribution. Second, the number of passages necessary to reach complete lubricant redistribution is determined. Finally, a textured surface with a cross-hatched pattern is introduced. Such a surface reduces the number of passages necessary to reach the complete redistribution. The choice of an optimized surface pattern can reduce the risk of local contact failure because of local lack of lubricant.
A study on starved micro-thermal elastohydrodynamic lubrication in simple sliding circular contacts
Authors: Wang J , Kaneta M
Published: May 2007

Numerical analyses based on Newtonian and Eyring fluid models are carried out to simulate the effects of inlet oil starvation in thermal elastohydrodynamic lubrication (TEHL) point contacts. It is assumed that the surface with transverse roughness is stationary and smooth surface is moving. Results of smooth TEHL contacts based on Newtonian fluid model are also presented as a reference. It is found that the temperature in the oil film increases suddenly at the inlet meniscus like the pressure build-up because of the discontinuous oil film at that boundary. The increasing degree of the inlet starvation raises the average temperature in the oil film for both smooth and rough contacts. The Newtonian maximum pressure and temperature for the rough contact occur at the macroscopic horseshoe-shaped constriction. Those of the Eyring fluid model still locate at the contact centre. As the degree of oil starvation increases, the differences in the pressure and film thickness distributions in rough elastohydrodynamic lubrication contacts between the Newtonian and Eyring fluid flow models decrease.
Biotribological behaviour of ultra-high molecular weight polyethylene composites containing Ti in a hip joint simulator
Authors: Wang Q , Zhang D , Ge S
Published: May 2007

The wear of ultra high-molecular weight polyethylene (UHMWPE) has been implicated as the major cause of osteolysis, implant loosening, and late aseptic failure in total hip arthroplasties in vivo, so increasing its wear resistance will be beneficial to obtain high-quality artificial joints. In this paper, the artificial joint acetabular materials of UHMWPE composites reinforced with titanium powders were prepared by the hot pressing formation method. A hip joint wear simulator was run to investigate the biotribological behaviours of these composites against 316L stainless steel in simulated body fluids (SBF-9) lubrication at 35 ± 1°C. The experimental results indicate that the addition of titanium particles in UHMWPE is beneficial for increasing wear resistance of UHMWPE. Under SBF-9 lubrication, the addition of titanium particles into UHMWPE has effect to decrease the wear rates of UHMWPE/Ti composites cups against 316L steel ball heads. The Maximum reduction in wear rates is 50 per cent for the UHMWPE/Ti composite cups with 20 (W) content of titanium particles. Abrasive wear and fatigue wear are found to be the main wear mechanisms of UHMWPE or UHMWPE/Ti composites in hip joint simulator wear under SBF-9 lubrication. The addition of titanium particles in UHMWPE will increase the wear debris size when the content of titanium particles is over 12 wt%.
Friction and wear performance of newly developed automotive bearing materials under boundary and mixed lubrication regimes
Authors: Kerr I , Priest M , Okamoto Y , Fujita M
Published: May 2007

Global legislation on emissions and on recyclability of vehicles makes it necessary to run main and connecting rod bearing systems in automobile internal combustion (IC) engines with lower friction using lower oil flows and less viscous oils leading to more contact between bearing and shaft. At the same time lead must be removed from the system. In order to design suitable bearing materials for these new applications it is important to understand the frictional behaviour of candidate materials in a range of conditions covering the boundary and mixed regimes.

Three plated plain bearing materials with overlays; a conventional lead based material, a newly developed bismuth based material, and a newly developed tin based system were tested on a tribometer specifically designed and built for this task to compare their performance in the boundary and mixed lubrication regimes under conditions that would be expected in an automobile engine. The resulting data was plotted as a series of Stribeck curves. The bismuth based material had slightly improved performance over the lead based material. The tin based material gave significantly higher friction, when compared with the other two materials.

The wear properties of the materials were also tested and the variation of wear factor with testing time was plotted for each of the material at two different operating conditions. All materials experienced more severe wear in the initial stages of operation. The tin based material had the most severe wear, and showed signs of incipient melting of the overlay. The bismuth and lead based materials showed similar wear with the bismuth based material being superior under the most severe conditions, whereas the lead based material was superior under the other conditions tested.

The bismuth material showed that it may be used as a suitable lead-free alternative material in IC engine applications under the conditions tested. The tin based material could not be used under such extreme conditions and failed because of thermal effects.
Micro- and nanoscopic biotribological behaviours in natural synovial joints and artificial joints
Authors: Murakami T , Sawae Y , Nakashima K , Yarimitsu S , Sato T
Published: May 2007

To maintain low friction and low wear in natural synovial joints and joint prostheses with artificial cartilage, adsorbed film formation at micro- and nanoscopic levels appears to play an important role in mixed or boundary lubrication regime where local direct contact occurs. In natural synovial joints, the lubricating gel film is likely to preserve low friction and to protect the bulk cartilage even after the removal of the adsorbed film. For poly (vinyl alcohol) (PVA) hydrogel as artificial cartilage without lubricating gel layer, the adsorbed film is a single protective barrier. In the previous researches on the rubbing pair of PVA against itself or glass plate, the coexistence of albumin ( A) and γ-globulin ( G) as A:G = 1: 2 at total protein concentration of 2.1 wt% in hyaluronate solution showed the lowest wear. In this study, in situ observation of adsorption of proteins was conducted to clarify the dynamic changes in adsorptional behaviours in lubricants containing different protein constituents. In the mixed lubrication regime, the coexistence of albumin and γ-globulin as A:G = 1:2 showed the lowest friction. The role of appropriate constituents of proteins is discussed on low friction and low wear at micro- and nanoscopic levels on the basis of previous and present results.
Effect of non-spherical bearing geometry on transient elastohydrodynamic lubrication in metal-on-metal hip joint implants
Authors: Wang F. C. , Jin Z. M.
Published: May 2007

A transient elastohydrodynamic lubrication model for non-spherical bearing surfaces of artificial hip joint implants under walking conditions has been developed. A nominal ball-in-socket configuration was employed to represent the articulation between a spherical femoral head and a non-spherical acetabular cup in this study. The non-sphericity of the bearing geometry was described by an ellipsoid with the variation of three ellipsoidal semi-axis lengths relative to the nominal spherical surface. An appropriate spherical coordinate system and mesh grids were selected to facilitate the numerical simulation. Both the equivalent discrete spherical convolution model and the corresponding spherical fast Fourier transform technique were used to evaluate the elastic deformation of both the spherical head and non-spherical cup surfaces. The transient lubrication model was subsequently adopted to investigate the effect of nonsphericity of an ellipsoidal cup on the transient elastohydrodynamic lubrication in a typical metal-on-metal hip joint implant. It was found that the non-sphericity could have a large effect on the predicted film thickness and the maximum pressure by as much as ∼43 and 17 per cent respectively, for the conditions considered in this study, depending on the orientation of the non-spherical cup relative to the flexion-extension direction. Furthermore, the non-sphericity of the cup bearing surface, which can be caused by shape tolerance in manufacturing or wear in clinical application, was discussed, in relation to the lubrication.
Abnormal film shapes in sliding elastohydrodynamic contacts lubricated by fatty alcohols
Authors: Yagi K , Vergne P
Published: May 2007

This paper describes abnormal film shapes in point sliding contacts lubricated by fatty alcohols. The original film thickness features have appeared under moderate film thickness conditions using lauric alcohol and 1-dodecanol, which have a low viscosity and pressure-viscosity coefficient as lubricants. The film thickness is measured by white-light interferometry applied to glass disc-steel ball contacts. When the slide to roll ratio increases, the film thickness distribution changes. The thickness increase can lead to values several times higher than those measured under pure rolling conditions. Keeping the mean entrainment speed constant, despite the same absolute values of the slide to roll ratios, the film thickness distributions when the ball speed is higher differ from those when the disc speed is higher.

The mechanisms that can explain such a new and unexpected EHL film behaviour are discussed using literature results and a simple thermal model that estimates the temperature increase at the solid surfaces and oil film. According to the results of the model, it is concluded that neither the temperature increase nor the temperature difference between the solid surfaces can explain the appearance of the abnormal film thickness features. However, the differences between the fluid responses suggest that the lubricant rheological behaviour contributes towards the observed phenomena.
Investigation of fundamental wear mechanisms at the piston ring and cylinder wall interface in internal combustion engines
Authors: Papadopoulos P , Priest M , Rainforth W. M.
Published: May 2007

This research examined the cylinder liner-piston ring system simultaneously from the metallurgical and metrological standpoints, using specimens cut from real engine components (rings and liners), in order to identify the mild and severe wear mechanisms.

Work has been conducted using a Plint TE77 high frequency friction machine. Metrological analysis was performed using stylus contacting profilometer. Metallurgical analysis of the samples was carried out using a JOEL JSM-6400 scanning electron microscope.

In addition to wear, the coefficient of friction (μ) was recorded for every piston ring - cylinder liner pair so as to observe the transitions between mixed and boundary lubrication. This paper presents the results obtained using flame sprayed Mo-coated spheroidal graphite cast iron, which is an old piston ring coating and is not available anymore, and relatively new Federal Mogul CKS-36™ top compression rings tested against a grey cast iron cylinder liner tested at two different bulk oil temperatures (90 °C and 140 °C), two different pressures (3.9 MPa and 6.5 MPa) and with two different lubricants (SAE 0W20 with a Friction Modifier and SAE 15W40).
Coefficient of friction in mixed film lubrication: Gears versus twin-discs
Authors: Castro J , Seabra J
Published: May 2007

This work compares the friction between two contacting discs with the friction between gear teeth, using a mixed film lubrication model developed for the evaluation of contact pressure and shear stress fields [5]. Such model is used to analyse twin-disc contacts with smooth surfaces and gear teeth contacts with rough surfaces, both lubricated with an additive-free ISO VG 150 mineral oil.

Experimental lubricant traction curves [4], measured in a twin-disc machine under full film elastohydrodynamic (EHD) lubrication (Λ > 2), were used to evaluate the lubricant rheological parameters, taking into account the surface roughness of the contacting discs. Experimental power loss measurements, made during gear efficiency tests performed in a Forschungsstelle für Zahnräder und Getriebebau (FZG) test rig [4], were used to evaluate the average friction coefficient between gear teeth along the meshing line, considering the surface roughness of the tooth flanks.

The experimental friction coefficients between gear teeth were compared with predictions obtained using three different approaches: (a) values directly extrapolated from the experimental lubricant traction curves, (b) values calculated using a full film EHD lubrication model, considering surface roughness, and (c) values from a mixed film lubrication model. These analysis were performed at three different scales, from the roughness peaks (inside contact) to the entire gear meshing line, passing through the contact dimension.

The results obtained show that the mixed film lubrication model is able to evaluate accurately the friction between gear teeth in power transmission equipment whatever the lubrication regime, boundary, mixed or full film.
Working memory as a predictor of written arithmetical skills in children: The importance of central executive functions
Authors: Andersson Ulf.
Published: May 2007

Background. The study was conducted in an attempt to further our understanding of how working memory contributes to written arithmetical skills in children.

Aim. The aim was to pinpoint the contribution of different central executive functions and to examine the contribution of the two subcomponents of children's written arithmetical skills.

Sample and method. A total of 141 third‐ and fourth‐graders were administered arithmetical tasks and measures of working memory, fluid IQ and reading. Regression analysis was used to examine the relationship between working memory and written arithmetical skills.

Results. Three central executive measures (counting span, trail making and verbal fluency) and one phonological loop measure (Digit Span) were significant and predictors of arithmetical performance when the influence of reading, age and IQ was controlled for in the analysis.

Conclusions. The present findings demonstrate that working memory, in general, and the central executive, in particular, contribute to children's arithmetical skills. It was hypothesized that monitoring and coordinating multiple processes, and accessing arithmetical knowledge from long‐term memory, are important central executive functions during arithmetical performance. The contribution of the phonological loop and the central executive (concurrent processing and storage of numerical information) indicates that children aged 9–10 years primarily utilize verbal coding strategies during written arithmetical performance.
Micromechanical modeling of solid-type and plate-type deformation patterns within softwood materials. A review and an improved approach
Authors: Hofstetter Karin , Hellmich Christian , Eberhardsteiner Josef
Published: May 2007

Wood exhibits a highly diverse microstructure. It appears as a solid-type composite material at a length scale of some micrometers, while it resembles an assembly of plate-like elements arranged in a honeycomb fashion at the length scale of some hundreds of micrometers. These structural features result in different load-carrying mechanisms at different observation scales and under different loading conditions. In this paper, we elucidate the main load-carrying mechanisms by means of a micromechanical model for softwood materials. Representing remarkable progress with respect to earlier models reported in the literature, this model is valid across various species. The model is based on tissue-independent stiffness properties of cellulose, lignin, hemicellulose, and water obtained from direct testing and lattice-dynamics analyses. Sample-specific characteristics are considered in terms of porosity and the contents of cellulose, lignin, hemicelluloses and water, which are obtained from mass density measurements, environmental scanning micrographs, analytical chemistry, and NMR spectroscopy. The model comprises three homogenization steps, two based on continuum micromechanics and one on the unit cell method. The latter represents plate-like bending and shear of the cell walls due to transverse shear loading and axial straining in the tangential stem direction. Accurate representation of these deformation modes results in accurate (orthotropic) stiffness estimates across a variety of softwood species. These stiffness predictions deviate, on average, by less than 10% from corresponding experimental results obtained from ultrasonic or quasi-static testing. Thus, the proposed model can reliably predict microscopic and macroscopic mechanical properties from internal structure and composition, and is therefore expected to significantly support wood production technology (such as drying techniques) and mechanical analyses of timber structures.
Field assessment of wood stake decomposition in forest soil
Authors: Wang Xiping , Page-Dumroese Deborah , Jurgensen Martin F. , Ross Robert J.
Published: May 2007

A pulse-echo acoustic method was investigated for evaluating wood stake decomposition in the field. A total of 58 wood stakes (29 loblolly pine, Pinus taeda, and 29 aspen, Populus tremuloides) that were vertically installed (full length) in forest soils were non-destructively tested by means of a laboratory-type acoustic measurement system. The same acoustic measurements were also conducted on the wood stakes after they were removed from the soil. Compression (parallel to grain) tests were then performed on the stakes in the laboratory to obtain residual elastic and strength properties. The results indicate that the pulse-echo acoustic method is a good approach to characterize wood stakes that are fully inserted into mineral soils. Statistical analysis showed good relationships between acoustic parameters (number of pulse echoes and in-ground acoustic velocity) and percentage weight loss, modulus of elasticity in compression, and residual compressive strength. The pulse-echo acoustic method could be used as a monitoring tool to assess progressive levels of wood stake decomposition in forest soil.
Derivatives of generalized Fourier expansions on the sphere
Authors: Gonzalez Vieli Francisco Javier
Published: May 2007

We show that the term by term derivative of the Fourier expansion in spherical
On the continuity of pseudo-differential operators on Besov spaces
Authors: Moussai Madani
Published: May 2007

We study the continuity of pseudo-differential operators on Besov space

for some positive real
Stability of disk-like galaxies – Part I: Stability via reduction
Authors: Fiřt Roman , Rein Gerhard
Published: May 2007

We prove the existence and stability of flat steady states of the Vlasov–Poisson system, which in astrophysics are used as models of disk-like galaxies. We follow the variational approach developed by GUO and REIN [5, 6, 7] for this type of problems and extend previous results of REIN [11]. In particular, we employ a reduction procedure which relates the stability problem for the Vlasov–Poisson system to the analogous question for the Euler–Poisson system.
Positive eigenfunctions for the p-Laplace operator revisited
Authors: Kawohl Bernd , Lindqvist Peter
Published: May 2007

We give a short proof that positive eigenfunctions for the
Protein kinase C activity mediates LH-induced ErbB/Erk signaling in differentiated hen granulosa cells
Authors: Woods Dori C , Johnson A L
Published: May 2007

While there is accumulating evidence that mitogen-activated protein kinase/Erk and protein kinase C (PKC) signaling inhibits premature differentiation of granulosa cells in hen prehierarchal follicles, it has only recently been established that these signaling pathways play an important facilitory role in promoting steroidogenesis in differentiated granulosa cells from preovulatory follicles. The present studies were conducted with differentiated granulosa cells to establish the ability of LH to initiate PKC activity, and the subsequent requirement for PKC activity in promoting the ErbB/Erk signaling cascade that ultimately facilitates LH-induced progesterone production. Incubation of differentiated granulosa cells with LH increases PKC activity within 15 min, and latently promotes Erk phosphorylation (P-Erk) by 180 min. Inhibition of PKC activity with GF109203X attenuates LH- and 8-bromo-cAMP (8-br-cAMP)-induced P-Erk, but not P-Erk promoted by an epidermal growth factor (EGF) family ligand (e.g., transforming growth factor α). Importantly, inhibition of PKC activity also blocks the LH-induced increase in the autocrine expression of mRNA encoding the EGF family ligands, such as EGF, amphiregulin, and betacellulin. Furthermore, inhibition of EGF ligand shedding at the level of the cell membrane using the matrix metalloprotease activity inhibitor, GM6001, prevents both LH- and 8-br-cAMP-induced P-Erk and progesterone production. These findings provide evidence for a facilitory role of PKC and ErbB/Erk signaling in LH-induced progesterone production, place the requirement for PKC activation upstream of ErbB/Erk activity, and demonstrate for the first time in a non-mammalian vertebrate the requirement for PKC activity in LH-induced expression of EGF family ligands in granulosa cells.
The expression of ovine placental lactogen, StAR and progesterone-associated steroidogenic enzymes in placentae of overnourished growing adolescent ewes
Authors: Lea Richard G , Wooding Peter , Stewart Ian , Hannah Lisa T , Morton Stephen , Wallace Karen , Aitken Raymond P , Milne John S , Regnault Timothy R , Anthony Russell V , Wallace Jacqueline M
Published: May 2007

Overnourishing pregnant adolescent sheep promotes maternal growth but reduces placental mass, lamb birth weight and circulating progesterone. This study aimed to determine whether altered progesterone reflected transcript abundance for StAR (cholesterol transporter) and the steroidogenic enzymes (Cyp11A1, Hsd3b and Cyp17). Circulating and placental expression of ovine placental lactogen (oPL) was also investigated. Adolescent ewes with singleton pregnancies were fed high (H) or moderate (M) nutrient intake diets to restrict or support placental growth. Experiment 1: peripheral progesterone and oPL concentrations were measured in H (n=7) and M (n=6) animals across gestation (days 7–140). Experiment 2: progesterone was measured to mid- (day 81; M: n=11, H: n=13) or late gestation (day 130; M: n=21, H: n=22), placental oPL, StAR and steroidogenic enzymes were measured by qPCR and oPL protein by immunohistochemistry. Experiment 1: in H vs M animals, term placental (P<0.05), total cotyledon (P<0.01) and foetal size (P<0.05) were reduced. Circulating oPL and progesterone were reduced at mid- (P<0.001, P<0.01) and late gestation (P<0.01, P<0.05) and oPL detection was delayed (P<0.01). Experiment 2: placental oPL was not altered by nutrition. In day 81 H animals, progesterone levels were reduced (P<0.001) but not related to placental or foetal size. Moreover, placental steroidogenic enzymes were unaffected. Day 130 progesterone (P<0.001) and Cyp11A1 (P<0.05) were reduced in H animals with intrauterine growth restriction (H+IUGR). Reduced mid-gestation peripheral oPL and progesterone may reflect altered placental differentiation and/or increased hepatic clearance respectively. Restricted placental growth and reduced biosynthesis may account for reduced progesterone in day 130 H+IUGR ewes.
Counting sperm does not add up any more: time for a new equation?
Authors: Lefièvre Linda , Bedu-Addo Kweku , Conner Sarah J , Machado-Oliveira Gisela S M , Chen Yongjian , Kirkman-Brown Jackson C , Afnan Masoud A , Publicover Stephen J , Ford W Christopher L , Barratt Christopher L R
Published: May 2007

Although sperm dysfunction is the single most common cause of infertility, we have poor methods of diagnosis and surprisingly no effective treatment (excluding assisted reproductive technology). In this review, we challenge the usefulness of a basic semen analysis and argue that a new paradigm is required immediately. We discuss the use of at-home screening to potentially improve the diagnosis of the male and to streamline the management of the sub-fertile couple. Additionally, we outline the recent progress in the field, for example, in proteomics, which will allow the development of new biomarkers of sperm function. This new knowledge will transform our understanding of the spermatozoon as a machine and is likely to lead to non-ART treatments for men with sperm dysfunction.
Perinatal Circulating Visfatin Levels in Intrauterine Growth Restriction
Authors: Malamitsi-Puchner Ariadne , Briana Despina D. , Boutsikou Maria , Kouskouni Evangelia , Hassiakos Demetrios , Gourgiotis Demetrios
Published: May 2007

OBJECTIVE. The objective of this study was to investigate possible alterations in circulating levels of the adipocytokine visfatin in intrauterine growth-restricted and normal pregnancies, given that these groups differ considerably in fetal nutrition, body fat mass, and metabolic/endocrine mechanisms.

METHODS. Serum visfatin levels were prospectively measured by enzyme immunoassay in 40 mothers and their 40 singleton term fetuses and neonates on postnatal days 1 and 4. Twenty neonates had intrauterine growth restriction (birth weight ≤3rd customized centile, adjusted for parameters that influence growth potential), and 20 were appropriate for gestational age.

RESULTS. Circulating maternal visfatin levels were significantly elevated in pregnancies with intrauterine growth restriction compared with control pregnancies with appropriate-for-gestational-age infants and negatively correlated with customized centiles in the group with intrauterine growth restriction. Postnatal day-1 and -4 visfatin levels were significantly higher in neonates with intrauterine growth restriction compared with neonates who were appropriate for gestational age. Postnatal-day-1 prefeeding insulin levels were significantly lower in neonates with intrauterine growth restriction.

CONCLUSIONS. Pathologic conditions in pregnancy that lead to intrauterine growth restriction could be responsible for elevated maternal visfatin levels. Higher visfatin levels in neonates with intrauterine growth restriction may serve as an early marker with prognostic value for later development of insulin resistance or type 2 diabetes, whereas lower insulin levels may indicate reduced β-cell mass and/or impaired β-cell function.
Strengthening of Platinum-5 wt.% Copper by Heat Treatment
Authors: Mshumi By Chumani , Lang Candy
Published: May 2007

Heat treatment of platinum-5 wt.% copper (Pt-5% Cu) below 500°C is known to result in an ordering transformation which can significantly increase the hardness of the alloy. Microsample tensile testing of Pt-5% Cu shows that low-temperature heat treatment of previously cold-worked specimens results in an increase in yield strength and tensile strength, with a maximum in strength occurring after heat treatment at 300°C; but ductility is unchanged.
The Electronic Structure of Platinum-Gold Alloy Particles
Authors: Bond By Geoffrey C.
Published: May 2007

Although the platinum-gold (Pt-Au) phase diagram shows a wide miscibility gap due to limited mutual solubility of the components, small particles (< 3 nm) form homogeneous alloys because all atoms retain their atomic electronic structure, and rehybridisation due to band formation does not take place. Supported Pt-Au catalysts are often superior to those containing Pt alone for low-temperature selective oxidations.
Osteochondral fragments involving the dorsomedial aspect of the proximal interphalangeal joint in young horses: 6 cases (1997–2006)
Authors: Fjordbakk Cathrine T. , Strand Eric , Milde Anne K. , Ihler Carl F. , Rorvik A. Magnus
Published: May 2007

Objective—To determine clinical and diagnostic imaging findings in young horses with osteochondral fragments involving the dorsomedial aspect of the proximal interphalangeal (PIP) joint.

Design—Retrospective case series.

Animals—6 horses.

Procedures—Medical records were reviewed. Follow-up information was obtained through telephone conversations with owners or trainers or by examining race records.

Results—Horses were between 1 and 4 years old. Three had bilateral osteochondral fragments in the forelimbs (n = 2 horses) or hind limbs (1). Radiographically, all but 1 fragment seemed to originate from the dorsomedial aspect of the distal end of the first phalanx. Fragment size ranged from 6 × 9mm to 11 × 21 mm. Three horses had lameness referable to the region of the affected joint; the other 3 horses did not have clinical signs referable to affected PIP joints. Two horses were euthanized shortly after diagnosis at the owners' request because of concerns that the horses would be unsuited for their intended athletic use. Two of the 3 horses in which fragments were incidental findings were able to race successfully, although 1 received intra-articular corticosteroid treatments; the third was retired because of unrelated orthopedic problems.

Conclusions and Clinical Relevance—Results suggested that osteochondral fragments involving the dorsomedial aspect of the PIP joint may be an incidental finding in young horses. Given the absence of clinical signs in 5 of 9 affected joints and the fact that 3 of 6 horses were affected bilaterally, a developmental origin of the fragments was suspected.
Prevalence of Mycoplasma bovis in backgrounding and stocker cattle operations
Authors: Wiggins Monique C. , Woolums Amelia R. , Sanchez Susan , Hurley David J. , Cole Dana J. , Ensley Douglas T. , Pence Mel E.
Published: May 2007

Objective—To characterize the prevalence of Mycoplasma bovis infection in backgrounding and stocker cattle operations and compare bacteriologic culture with PCR assay for detection of M bovis.

Design—Prospective descriptive study.

Animals—432 calves, 3 to 9 months old, from 9 operations.

Procedures—2 nasal swab specimens were collected from each calf. Swab specimens were evaluated via bacteriologic culture and PCR assay for organisms of the class Mollicutes and M bovis. Culture results were considered negative if no growth occurred within 21 days. Positive results were indicated by characteristic colony formation with PCR assay confirmation. Deoxyribonucleic acid was extracted from 1 swab specimen for direct PCR assay for Mollicutes and M bovis.

Results—Of 432 calves, 374 (87%) had positive results for Mollicutes via PCR assay and 63 (15%) via culture. Seven (2%) calves had positive results for M bovis via PCR assay and 10 (2%) via culture. Prevalence of Mollicutes at the farm level ranged from 54% to 100% via PCR assay and from 0% to 59% via culture. Prevalence of M bovis at the farm level ranged from 0% to 4% via PCR assay and from 0% to 6% via culture. Calves that shed M bovis were significantly more likely to have a fever than were calves that did not shed M bovis.

Conclusions and Clinical Relevance—M bovis was detected at a low level in recently purchased backgrounded and stocker calves in Georgia. Although slightly more infected calves were detected via culture and PCR assay together, PCR assay appeared to accurately identify M bovis at the farm level.
On Modeling Choice and Frequency of Home-Based Telecommuting
Authors: Pouri Yasasvi D. , Bhat Chandra R.
Published: May 2007

A joint model of home-based telecommuting choice and weekly telecommuting frequency is proposed. The model is applied to an empirical analysis by using data from a household survey conducted by the New York Metropolitan Transportation Council. The empirical results underscore the importance of socioeconomic and occupational characteristics of employees in explaining telecommuting behavior. Further, the analysis indicates that failure to accommodate common unobserved factors affecting telecommuting choice and frequency can lead to inconsistent estimation of the effects of exogenous variables and misleading projections of the magnitude of telecommuting.
Promotion of Healthy Eating:Among New Immigrant Women in Ontario
Authors: Hyman Ilene , Guruge Sepali , Makarchuk Mary-Jo , Cameron Jill , Micevski Vaska
Published: May 2007

Little attention has been given to the dietary patterns of new immigrant women in Canada. Research suggests that before migration, many immigrants, especially those from non-Western countries, consume a healthy diet, but this changes on migration. This paper presents information from a recently completed literature review conducted for the Women's Health Council of the Ontario Ministry of Health and Long-Term Care. The paper includes a review of the major determinants of food choice and health promotion strategies appropriate to new immigrant women. Our findings suggest that nutrition intervention for new immigrant women must consider the social context of these women's lives, address cultural, linguistic, economic and informational barriers and consider how these change over time. Recommendations are also made on how to best promote healthy eating in this group.