bluuebunny/crossref_metadata_2025 huggingface dataset:
Discussion1‐“Stream Temperature Relationships to Forest Harvest in Western Washington” by Michael M. Pollock, Timothy J. Beechie, Martin Liermann, and Richard E. Bigley2
Authors: Ice George G. , Brown George W. , Gravelle John A. , Rhett Jackson C. , Light Jeffrey T. , Link Timothy E. , Martin Douglas J. , McGreer Dale J. , Skaugset Arne E.
Published: April 2010

Ice, George G., George W. Brown, John A. Gravelle, C. Rhett Jackson, Jeffrey T. Light, Timothy E. Link, Douglas J. Martin, Dale J. McGreer, and Arne E. Skaugset, 2010. Discussion –“Stream Temperature Relationships to Forest Harvest in Western Washington” by Michael M. Pollock, Timothy J. Beechie, Martin Liermann, and Richard E. Bigley.Journal of the American Water Resources Association(JAWRA) 46(4): 838‐842. DOI: 10.1111/j.1752‐1688.2010.00441.x
Effects of reforestation age on moth assemblages in plantations and naturally regenerated forests
Authors: TAKI HISATOMO , YAMAURA YUICHI , OKOCHI ISAMU , INOUE TAKENARI , OKABE KIMIKO , MAKINO SHUN’ICHI
Published: April 2010

Abstract.  1. Tree harvesting, an anthropogenic disturbance, and natural disturbances, such as avalanches, windstorms, fires, and floods, drive forest reestablishment. Chrono‐sequential changes in plant communities as well as reforestation caused by harvesting and natural disturbances can affect forest faunal assemblages.

2. The effects of reforestation age, from recently harvested to old growth between 1 and 178 years old, on moth assemblages were examined for two types of reforestation: plantations and natural regeneration.

3. In total, 7848 individuals representing 579 species of moths were collected using black lights and then identified. In plantation forests, species richness and abundance responded unimodally to succession age, whereas in naturally regenerated forests, species richness and abundance did not significantly respond to succession age. In addition, the community structure of moth assemblages varied greatly in relation to succession age in both reforestation types.

4. These findings suggest that if the diversity of moth assemblages changes within and among forest stands of different successional stages, forest stands can provide habitat for unique moth assemblages. Thus, intentional forest management may enable the maintenance of greater moth diversity within a heterogeneous landscape or region. Various land‐use practices, such as old growth forest conservation and short‐length harvests, associated with forest types at the level of the forest stand could result in forest mosaics at the landscape or regional scale.
Improve your image ‐ 6: films and processing
Authors: DAVIES J. V.
Published: April 2010

The photograph is created by the deposition of metallic silver in a pattern on film. This is caused by the ionisation of silver halide grains on the film and their subsequent development.

Chemical processing converts the latent image into a visible image and fixes it for viewing purposes.

Processing is an exact laboratory reaction that should be performed with precision in an appropriate environment. It is temperature and time dependent and relies on the use of fresh chemical solutions that have been accurately prepared.

Most radiographic faults in veterinary practice happen in the darkroom and many relate to the processing reaction itself. The most common problem is underdevelopment and this may be the result of inadequate temperature, too short a reaction time or old chemicals.

Film and chemistry should be compatible and the manufacturer's instructions followed precisely.

Automatic processors may seem expensive, but they produce a consistent result in a fraction of the time. They are cost effective in all but the smallest of practices. Efficient production will facilitate greater radiographic volume, which adds to its cost effectiveness.
Ultrasonography of the equine stifle
Authors: Dik K. J.
Published: April 2010

Seven horses with stifle injury are reported with emphasis on the use of ultrasonography vs. radiography in diagnosis. Two had medial meniscal damage associated with collateral ligamentous sprain, fracture or with haemarthrosis. Two had a periarticular abscess, In 1 horse communicating with the lateral femorotibial joint. One foal had haematogenous focal subchondral epiphyseal osteomyelitis extending in the overlying articular cartilage. One horse had osteochondrosis dissecans, the detached fragments migrated and attached to the capsule of the lateral femorotibial joint. One foal had periarticular muscle injury associated with peroneal nerve paralysis. Only in the foal ultrasonography was considered the imaging modality of choice. In all other cases ultrasonography and radiography represented valuable and complementary diagnostic procedures.
Isolation of infectious equine cases
Authors: Brazil T. J.
Published: April 2010

• When in doubt isolate sick horses

• Healthy in contact horses must be treated as incubators of the disease

• Attempt to confirm diagnosis rapidly

• Movement of in contact horses almost always spreads the disease

• Stop all horse traffic on and off premises

• Minimise horse and human traffic on premises

• Seek advice on epizootiology of disease if unsure

• Minimise contamination by aggressive cleansing and appropriate disinfection

• Strictly enforce and monitor isolation protocois

• Isolation procedures can be costly but spread of the disease costs much more.
Equine hypothyroidism: the difficulties of diagnosis
Authors: Mooney Carmel T. , Murphy D.
Published: April 2010

In summary, there is substantial evidence suggesting that hypothyroidism exists in the foal and may be occasionally encountered in practice. However, there is limited evidence suggesting that hypothyroidism exists in the adult horse and the selection of cases for further investigation will be exceptionally rare. In the evaluation of such cases, nonthyroidal illnesses should be excluded and if possible drug therapy stopped for at least 10 days prior to testing (Beech 1987). If serum total T4 and T3 concentrations are abnormal, confirmation of the diagnosis should be attempted by a TSH/TRH stimulation test. If a normal response is elicited, primary hypothyroidism does not exist and an alternative diagnosis should be considered. In the exceptional case of the diagnosis being confirmed, treatment can be instituted using L‐thyroxine at a daily dose of 20 μg/kg with dosage adjustments depending on serum thyroid hormone concentrations (Chenet al.1984).

On hearsay evidence, thyroid hormone supplementation of horses has been advocated as a means of increasing performance but such a response does not confirm a diagnosis of hypothyroidism. On current and more scientific evidence, poor performance is unlikely to relate to thyroid dysfunction.
Recognition and management of fluid and electrolyte changes in performance horses
Authors: King A.
Published: April 2010

In summary, the treatment of metabolic disorders under field conditions at equestrian events requires a basic understanding of the effects of the fluid, electrolyte and energy losses that contribute to the development of the disorders.

Early recognition and treatment with oral or i.v. fluids, even in the absence of clinical dehydration, in the quantities outlined above, often alleviate the disorders without the need to administer any other drugs. Furthermore, drugs that may be indicated for treatment of these disorders are often contraindicated in dehydrated horses.
Subchondral bone cysts in the horse: aetiology, diagnosis and treatment options
Authors: McIlwraith C. W.
Published: April 2010

In summary, there is still controversy with regard to subchondral bone cysts in the horse but in the last 10 years we have gathered much useful information, both on pathogenesis and treatment. It is clear that osteochondrosis is not the only means of acquiring a subchondral bone cyst. We also have good data on the response to surgical treatment in the femorotibial joint and fetlock joint. We have less extensive data on the treatment in the pastern, coffin and elbow joint. Whether cancellous bone graft augments healing is still controversial. At the moment the author feels that the most important principles are enucleation of the cyst and suppression of any ongoing inflammatory reaction that can cause progressive lysis after surgical curettage.
A gap principle for dynamics
Authors: Benedetto Robert L. , Ghioca Dragos , Kurlberg Pär , Tucker Thomas J.
Published: April 2010

Let f1,…,fg∈ℂ(z) be rational functions, let Φ=(f1,…,fg) denote their coordinate-wise action on (ℙ1)g, let V ⊂(ℙ1)g be a proper subvariety, and let P be a point in (ℙ1)g(ℂ). We show that if 𝒮={n≥0:Φn(P)∈V (ℂ)} does not contain any infinite arithmetic progressions, then 𝒮 must be a very sparse set of integers. In particular, for any k and any sufficiently large N, the number of n≤N such that Φn(P)∈V (ℂ) is less than log kN, where log k denotes the kth iterate of the log function. This result can be interpreted as an analogue of the gap principle of Davenport–Roth and Mumford.
The Biomechanical Consequence of Insufficient Femoral Component Lateralization and Exposed Cancellous Bone in Hip Resurfacing Arthroplasty
Authors: Olsen Michael , Davis Edward T. , Whyne Cari M. , Zdero Rad , Schemitsch Emil H.
Published: April 2010

Insufficient lateralization of the femoral component coupled with exposed reamed cancellous bone has been speculated to predispose to femoral neck fracture. The current study examined the effect of mediolateral implant position and exposed cancellous bone on the strength of the resurfaced proximal femur. Composite femurs were prepared in three configurations: (1) partial, with the implant placed at the native femoral head offset of the femur, partially exposing reamed cancellous bone; (2) proud, with a medialized implant exposing a circumferential ring of cancellous bone; and (3) complete, with a lateralized implant covering all reamed cancellous bone. Specimens were loaded to failure in axial compression. A finite element model was used to further explore the effect of exposed cancellous bone, cement mantle thickness, and relative valgus orientation on the strain distributions in the resurfaced femur. The proud group (2063 N) was significantly weaker than both the partial (2974 N, p=0.004) and complete groups (5899 N, p=0.001) when tested to failure. The partial group was also significantly weaker than the complete group when tested to failure (p=0.001). The finite element model demonstrated increasing levels of strain in the superior reamed cortical-cancellous bone interface with increasing degree of exposed cancellous bone. The condition of the femoral component medialized as the result of a thick cement mantle had the greatest detrimental impact on strain level in the superior reamed cancellous bone while a valgus oriented implant provided a protective effect. This study provides biomechanical evidence that exposed reamed cancellous bone significantly reduces the load-to-failure and increases maximum strains in the resurfaced proximal femur. The perceived benefit of reconstructing the femur to its native geometry may inherently weaken the proximal femur and increase femoral neck fracture risk if the femoral component is not sufficiently lateralized to cover all unsupported reamed cancellous bone. Relative valgus orientation of the implant may help to minimize the risk of neck fracture if reamed cancellous bone remains exposed following implant impaction.
The Response of Human Aortic Endothelial Cells in a Stenotic Hemodynamic Environment: Effect of Duration, Magnitude, and Spatial Gradients in Wall Shear Stress
Authors: Rouleau Leonie , Rossi Joanna , Leask Richard L.
Published: April 2010

Inflammation plays a key role in the development and stability of coronary plaques. Endothelial cells alter their expression in response to wall shear stress (WSS). Straight/tubular and asymmetric stenosis models were designed to study the localized expression of atheroprone molecules and inflammatory markers due to the presence of the spatial wall shear stress gradients created by an eccentric plaque. The effects of steady wall shear stress duration (0–24 h) and magnitude (4.5–18 dynes/cm2) were analyzed in human abdominal aortic endothelial cells through quantitative real-time polymerase chain reaction (PCR) and immunofluorescence analysis in straight/tubular models. Regional expression was assessed by immunofluorescence and confocal microscopy in stenosis models. Under steady fully developed flow, endothelial cells exhibited a sustained increase in levels of atheroprotective genes with WSS duration and magnitude. The local response in the stenosis model showed that expression of endothelial nitric oxide synthase and Kruppel-like factor 2 is magnitude rather than gradient dependent. A WSS magnitude dependent transient increase in translocation of transcription factor nuclear factor κB was observed. Intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin exhibited a sustained increase in protein expression with time. The mRNA levels of these molecules were transiently upregulated and this was followed by a decrease in expression to levels lower than static controls. Regionally, increased inflammatory marker expression was observed in regions of WSS gradients both proximal and distal to the stenosis when compared with the uniform flow regions, whereas the atheroprotective markers were expressed to a greater extent in regions of elevated WSS magnitudes. The results from the straight/tubular model cannot explain the regional variation seen in the stenosis models. This may help explain the localization of inflammatory cells at the shoulders of plaques in vivo.
Trans-Thrombus Blood Pressure Effects in Abdominal Aortic Aneurysms
Authors: Meyer Clark A. , Guivier-Curien Carine , Moore James E.
Published: April 2010

How much and how the thrombus supports the wall of an abdominal aortic aneurysm (AAA) is unclear. While some previous studies have indicated that thrombus lacks the mechanical integrity to support much load compared with the aneurysm wall, others have shown that removing thrombus in computational AAA models drastically changes aneurysm wall stress. Histopathological studies have shown that thrombus properties vary through the thickness and it can be porous. The goal of this study is to explore the variations in thrombus properties, including the ability to isolate pressure from the aneurysm wall, incomplete attachment, and their effects on aneurysm wall stress, an important parameter in determining risk for rupture. An analytical model comprised of cylinders and two patient specific models were constructed with pressurization boundary conditions applied at the lumen or the thrombus/aneurysm wall interface (to simulate complete transmission of pressure through porous thrombus). Aneurysm wall stress was also calculated in the absence of thrombus. The potential importance of partial thrombus attachment was also analyzed. Pressurizing at either surface (lumen versus interface) made little difference to mean von Mises aneurysm wall stress values with thrombus completely attached (3.1% analytic, 1.2% patient specific) while thrombus presence reduced mean von Mises stress considerably (79% analytic, 40–46% patient specific) in comparison to models without it. Peak von Mises stresses were similarly influenced with pressurization surface differing slightly (3.1% analytic, 1.4% patient specific) and reductions in stress by thrombus presence (80% analytic, 28–37% patient specific). The case of partial thrombus attachment was investigated using a cylindrical model in which there was no attachment between the thrombus and aneurysm wall in a small area (10 deg). Applying pressure at the lumen resulted in a similar stress field to fully attached thrombus, whereas applying pressure at the interface resulted in a 42% increase in peak aneurysm wall stress. Taken together, these results show that the thrombus can have a wall stress reducing role even if it does not shield the aneurysm wall from direct pressurization—as long as the thrombus is fully attached to the aneurysm wall. Furthermore, the potential for porous thrombus to transmit pressure to the interface can result in a considerable increase in aneurysm wall stress in cases of partial attachment. In the search for models capable of accurately assessing the risk for rupture, the nature of the thrombus and its attachment to the aneurysm wall must be carefully assessed.
Generalized Anisotropic Inverse Mechanics for Soft Tissues
Authors: Raghupathy Ramesh , Barocas Victor H.
Published: April 2010

Elastography, which is the imaging of soft tissues on the basis of elastic modulus (or, more generally, stiffness) has become increasingly popular in the last decades and holds promise for application in many medical areas. Most of the attention has focused on inhomogeneous materials that are locally isotropic, the intent being to detect a (stiff) tumor within a (compliant) tissue. Many tissues of mechanical interest, however, are anisotropic, so a method capable of determining material anisotropy would be attractive. We present here an approach to determine the mechanical anisotropy of inhomogeneous, anisotropic tissues, by directly solving the finite element representation of the Cauchy stress balance in the tissue. The method divides the sample domain into subdomains assumed to have uniform properties and solves for the material constants in each subdomain. Two-dimensional simulated experiments on linear anisotropic inhomogeneous systems demonstrate the ability of the method, and simulated experiments on a nonlinear model demonstrate the ability of the method to capture anisotropy qualitatively even though only a linear model is used in the inverse problem. As with any inverse problem, ill-posedness is a serious concern, and multiple tests may need to be done on the same sample to determine the properties with confidence.
Reduction of Procoagulant Potential of b-Datum Leakage Jet Flow in Bileaflet Mechanical Heart Valves via Application of Vortex Generator Arrays
Authors: Murphy David W. , Dasi Lakshmi P. , Vukasinovic Jelena , Glezer Ari , Yoganathan Ajit P.
Published: April 2010

Current designs of bileaflet mechanical heart valves put patients at an increased risk of thromboembolism. In particular, regurgitant flow through the b-datum line is associated with nonphysiologic flow characteristics such as elevated shear stresses, regions of recirculation, and increased mixing, all of which may promote thrombus formation. We have previously shown that passive flow control in the form of vortex generators mounted on the downstream leaflet surfaces can effectively diminish turbulent stresses. The objective of the current work is thus to determine the effect of vortex generators on the thromboembolic potential of the b-datum line leakage jet and to correlate that effect with the vortex generator-induced changes to the flow structure. Flow experiments were performed using a steady model of the transient b-datum line jet. These experiments encompassed flow visualization to gain an overall picture of the flow system, particle image velocimetry to quantify the flow field in detail, and in vitro experiments with human blood to quantify thrombus formation in response to the applied passive flow control. Thrombus formation was quantified over time by an assay for thrombin-antithrombin III (TAT III). In comparing results with and without vortex generators, significantly lower mean TAT III levels were observed at one time point for the case with vortex generators. Also, the TAT III growth rate of the case with vortex generators was significantly lower. While no differences in jet spreading were found with and without vortex generators, lower peak turbulent stresses were observed for the case with vortex generators. The results thus demonstrate the potential of applying passive flow control to cardiovascular hardware in order to mitigate the hemodynamic factors leading to thrombus formation.
Carotid Bifurcation Hemodynamics in Older Adults: Effect of Measured Versus Assumed Flow Waveform
Authors: Hoi Yiemeng , Wasserman Bruce A. , Lakatta Edward G. , Steinman David A.
Published: April 2010

Recent work has illuminated differences in carotid artery blood flow rate dynamics of older versus young adults. To what degree flow waveform shape, and indeed the use of measured versus assumed flow rates, affects the simulated hemodynamics of older adult carotid bifurcations has not been elucidated. Image-based computational fluid dynamics models of N=9 normal, older adult carotid bifurcations were reconstructed from magnetic resonance angiography. Subject-specific hemodynamics were computed by imposing each individual’s inlet and outlet flow rates measured by cine phase-contrast magnetic resonance imaging or by imposing characteristic young and older adult flow waveform shapes adjusted to cycle-averaged flow rates measured or allometrically scaled to the inlet and outlet areas. Despite appreciable differences in the measured versus assumed flow conditions, the locations and extents of low wall shear stress and elevated relative residence time were broadly consistent; however, the extent of elevated oscillatory shear index was substantially underestimated, more by the use of assumed cycle-averaged flow rates than the assumed flow waveform shape. For studies of individual vessels, use of a characteristic flow waveform shape is likely sufficient, with some benefit offered by scaling to measured cycle-averaged flow rates. For larger-scale studies of many vessels, ranking of cases according to presumed hemodynamic or geometric risk is robust to the assumed flow conditions.
Sensitivity of CFD Based Hemodynamic Results in Rabbit Aneurysm Models to Idealizations in Surrounding Vasculature
Authors: Zeng Zijing , Kallmes David F. , Durka Michael J. , Ding Yonghong , Lewis Debra , Kadirvel Ramanathan , Robertson Anne M.
Published: April 2010

Computational fluid dynamics (CFD) studies provide a valuable tool for evaluating the role of hemodynamics in vascular diseases such as cerebral aneurysms and atherosclerosis. However, such models necessarily only include isolated segments of the vasculature. In this work, we evaluate the influence of geometric approximations in vascular anatomy on hemodynamics in elastase induced saccular aneurysms in rabbits. One representative high aspect ratio (AR—height/neck width) aneurysm and one low AR aneurysm were created at the origin of the right common carotid artery in two New Zealand white rabbits. Three-dimensional (3D) reconstructions of the aneurysm and surrounding arteries were created using 3D rotational angiographic data. Five models with varying extents of neighboring vasculature were created for both the high and low AR cases. A reference model included the aneurysm sac, left common carotid artery (LCCA), aortic arch, and downstream trifurcation/quadrification. Three-dimensional, pulsatile CFD studies were performed and streamlines, wall shear stress (WSS), oscillatory shear index, and cross sectional velocity were compared between the models. The influence of the vascular domain on intra-aneurysmal hemodynamics varied between the low and high AR cases. For the high AR case, even a simple model including only the aneurysm, a small section of neighboring vasculature, and simple extensions captured the main features of the steamline and WSS distribution predicted by the reference model. However, the WSS distribution in the low AR case was more strongly influenced by the extent of vasculature. In particular, it was necessary to include the downstream quadrification and upstream LCCA to obtain good predictions of WSS. The findings in this work demonstrate the accuracy of CFD results can be compromised if insufficient neighboring vessels are included in studies of hemodynamics in elastase induced rabbit aneurysms. Consideration of aspect ratio, hemodynamic parameters of interest, and acceptable magnitude of error when selecting the vascular domain will increase reliability of the results while decreasing computational time.
A Large Strain Material Model for Soft Tissues With Functionally Graded Properties
Authors: Görke Uwe-Jens , Günther Hubert , Nagel Thomas , Wimmer Markus A.
Published: April 2010

The reaction of articular cartilage and other soft tissues to mechanical loads has been characterized by coupled hydraulic (H) and mechanical (M) processes. An enhanced biphasic material model is presented, which may be used to describe the load response of soft tissue. A large-strain numerical approach of HM coupled processes has been applied. Physical and geometrical nonlinearities, as well as anisotropy and intrinsic rate-dependency of the solid skeleton have been realized using a thermodynamically consistent approach. The presented material model has been implemented into the commercially available finite element code MSC MARC. Initial verification of the model has been conducted analytically in tendonlike structures. The poroelastic and intrinsic viscoelastic features of the model were compared with the experimental data of an unconfined compression test of agarose hydrogel. A recent example from the area of cartilage research has been modeled, and the mechanical response was compared with cell viability. All examples showed good agreement between numerical and analytical/experimental results.
Numerical Modeling of Stress in Stenotic Arteries With Microcalcifications: A Micromechanical Approximation
Authors: Wenk Jonathan F. , Papadopoulos Panayiotis , Zohdi Tarek I.
Published: April 2010

Most finite element models of atherosclerotic arteries do not account for the heterogeneity of the plaque constituents at the microscale. Failure of plaque lesions has been shown to be a local event, linked to stress concentrations caused by cap thinning, inflammation, macroscopic heterogeneity, and recently, the presence of microcalcifications. There is growing evidence that microcalcifications exist in the fibrous cap of plaque lesions. However, their role is not yet fully understood. The goal of the present work is to investigate the effects of localized regions of microcalcifications on the stress field of atherosclerotic plaque caps in a section of carotid artery. This is achieved by performing finite element simulations of three-dimensional fluid-structure interaction models. The material response in the region of microcalcification is modeled using a combination of finite elements, homogenization theory, and a stress concentration function that approximates the average local stresses in the fibrous tissue and microcalcification phases. The results indicate that the circumferential stress in the fibrous tissue phase increases as the volume fraction of microcalcifications is increased, and that the stress exceeds a critical threshold when the fibrous cap thickness is decreased. Furthermore, the presence of the microcalcifications significantly influences the distribution of stress by shifting the maximum circumferential stress away from the cap shoulders, where failure is most common when the effective region of microcalcification is located at the center of the cap. This is a possible explanation of why 40% of plaque ruptures occur away from the shoulder region of the cap.
A Finite Element Model for Direction-Dependent Mechanical Response to Nanoindentation of Cortical Bone Allowing for Anisotropic Post-Yield Behavior of the Tissue
Authors: Carnelli D. , Gastaldi D. , Sassi V. , Contro R. , Ortiz C. , Vena P.
Published: April 2010

A finite element model was developed for numerical simulations of nanoindentation tests on cortical bone. The model allows for anisotropic elastic and post-yield behavior of the tissue. The material model for the post-yield behavior was obtained through a suitable linear transformation of the stress tensor components to define the properties of the real anisotropic material in terms of a fictitious isotropic solid. A tension-compression yield stress mismatch and a direction-dependent yield stress are allowed for. The constitutive parameters are determined on the basis of literature experimental data. Indentation experiments along the axial (the longitudinal direction of long bones) and transverse directions have been simulated with the purpose to calculate the indentation moduli and the tissue hardness in both the indentation directions. The results have shown that the transverse to axial mismatch of indentation moduli was correctly simulated regardless of the constitutive parameters used to describe the post-yield behavior. The axial to transverse hardness mismatch observed in experimental studies (see, for example, Rho et al. [1999, “Elastic Properties of Microstructural Components of Human Bone Tissue as Measured by Nanoindentation,” J. Biomed. Mater. Res., 45, pp. 48–54] for results on human tibial cortical bone) can be correctly simulated through an anisotropic yield constitutive model. Furthermore, previous experimental results have shown that cortical bone tissue subject to nanoindentation does not exhibit piling-up. The numerical model presented in this paper shows that the probe tip-tissue friction and the post-yield deformation modes play a relevant role in this respect; in particular, a small dilatation angle, ruling the volumetric inelastic strain, is required to approach the experimental findings.
Modeling of Laser Coagulation of Tissue With MRI Temperature Monitoring
Authors: Chen Xin , Saidel Gerald M.
Published: April 2010

Light energy from a laser source that is delivered into body tissue via a fiber-optic probe with minimal invasiveness has been used to ablate solid tumors. This thermal coagulation process can be guided and monitored accurately by continuous magnetic resonance imaging (MRI) since the laser energy delivery system does not interfere with MRI. This report deals with mathematical modeling and analysis of laser coagulation of tissue. This model is intended for “real-time” analysis of magnetic resonance images obtained during the coagulation process to guide clinical treatment. A mathematical model is developed to simulate the thermal response of tissue to a laser light heating source. For fast simulation, an approximate solution of the thermal model is used to predict the dynamics of temperature distribution and tissue damage induced by a laser energy line source. The validity of these simulations is tested by comparison with MRI-based temperature data acquired from in vivo experiments in rabbits. The model-simulated temperature distribution and predicted lesion dynamics correspond closely with MRI-based data. These results demonstrate the potential for using this combination of fast modeling and MRI technologies during laser heating of tissue for online prediction of tumor lesion size during laser heating.
Determination of Passive Moment-Angle Relationships at the Trapeziometacarpal Joint
Authors: Domalain Mathieu , Vigouroux Laurent , Berton Eric
Published: April 2010

While modeling the trapeziometacarpal (TMC) joint for determination of tendon forces, the TMC has been considered frictionless and passive moments created by soft tissues neglected. This, however, becomes inaccurate when reaching the joint end range of motion and considering that the TMC is entirely crossed by a complex network of skin, ligaments, soft tissues, and tendons. The objective of this study was to evaluate the passive moments with respect to joint posture in order to further include this relationship in biomechanical modeling. An experimental method was proposed to estimate in vivo a global passive moment including the sum of the actions of each passive anatomical structure. An external force was applied at the level of the metacarpophalangeal joint in various directions ranging from neutral position to full extension and full adduction to full abduction. The passive moment was computed and expressed as a function of the adopted joint angles. An exponential regression was then developed to fit the experimental data and to propose a generic passive moment model. Results showed a good agreement between the proposed exponential regression model and the experimental measures. Moreover, it was shown that joint stiffness could represent more than 60% of the net joint moment during a typical pulp grip task. These results showed the necessity to include the data in biomechanical modeling. The results may help predict more realistic tendons force especially in abduction/adduction muscles.
Gait Modification via Verbal Instruction and an Active Feedback System to Reduce Peak Knee Adduction Moment
Authors: Dowling Ariel V. , Fisher David S. , Andriacchi Thomas P.
Published: April 2010

The purpose of this study was to introduce a simple gait training method using real-time gait modification to reduce the peak knee adduction moment during walking by producing a subtle weight bearing shift to the medial side of the foot. The hypothesis of this study was that this weight shift could be achieved via either verbal instruction or an active feedback system, and that the weight shift would result in a reduction in the first peak knee adduction moment compared with the control tests. Nine individuals were tested during walking using two intervention methods: verbal instruction and an active feedback system placed on the right shoe. The first peak of the knee adduction moment for each condition was assessed using a motion capture system and force plate. The active feedback system significantly reduced (14.2%) the peak knee adduction moment relative to the control. This study demonstrated that a subtle weight bearing shift to the medial side of the foot produced with an active feedback system during walking reduced the first peak of the knee adduction moment and suggests the potential application of this method to slow the rate of progression of medial compartment knee osteoarthritis.
A Generalized Continuum Formulation for Composite Microcracked Materials and Wave Propagation in a Bar
Authors: Trovalusci Patrizia , Varano Valerio , Rega Giuseppe
Published: April 2010

A multifield continuum is adopted to grossly describe the dynamical behavior of composite microcracked solids. The constitutive relations for the internal and external (inertial) actions are obtained using a multiscale modeling based on the hypotheses of the classical molecular theory of elasticity and the ensuing overall elastodynamic properties allow us to take properly into account the microscopic features of these materials. Referring to a one-dimensional microcracked bar, the ability of such a continuum to reveal the presence of internal heterogeneities is investigated by analyzing the relevant dispersive wave propagation properties. Scattering of traveling waves is shown to be associated with the microcrack density in the bar.
Comparative Transcriptomic and Proteomic Profiling of Industrial Wine Yeast Strains
Authors: Rossouw Debra , van den Dool Adri H. , Jacobson Dan , Bauer Florian F.
Published: April 2010

The geno- and phenotypic diversity of commercial
Saccharomyces cerevisiae
wine yeast strains provides an opportunity to apply the system-wide approaches that are reasonably well established for laboratory strains to generate insight into the functioning of complex cellular networks in industrial environments. We have previously analyzed the transcriptomes of five industrial wine yeast strains at three time points during alcoholic fermentation. Here, we extend the comparative approach to include an isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomic analysis of two of the previously analyzed wine yeast strains at the same three time points during fermentation in synthetic wine must. The data show that differences in the transcriptomes of the two strains at a given time point rather accurately reflect differences in the corresponding proteomes independently of the gene ontology (GO) category, providing strong support for the biological relevance of comparative transcriptomic data sets in yeast. In line with previous observations, the alignment proves to be less accurate when assessing intrastrain changes at different time points. In this case, differences between the transcriptome and proteome appear to be strongly dependent on the GO category of the corresponding genes. The data in particular suggest that metabolic enzymes and the corresponding genes appear to be strongly correlated over time and between strains, suggesting a strong transcriptional control of such enzymes. The data also allow the generation of hypotheses regarding the molecular origin of significant differences in phenotypic traits between the two strains.
Calflagin Inhibition Prolongs Host Survival and Suppresses Parasitemia in Trypanosoma brucei Infection
Authors: Emmer Brian T. , Daniels Melvin D. , Taylor Joann M. , Epting Conrad L. , Engman David M.
Published: April 2010

African trypanosomes express a family of dually acylated, EF-hand calcium-binding proteins called the calflagins. These proteins associate with lipid raft microdomains in the flagellar membrane, where they putatively function as calcium signaling proteins. Here we show that these proteins bind calcium with high affinity and that their expression is regulated during the life cycle stage of the parasite, with protein levels approximately 10-fold higher in the mammalian bloodstream form than in the insect vector procyclic stage. We also demonstrate a role for the calflagins in mammalian infection, as inhibition of the entire calflagin family by RNA interference dramatically increased host survival and attenuated parasitemia in a mouse model of sleeping sickness. In contrast to infection with parental wild-type parasites, which demonstrated an unremitting parasitemia and death within 6 to 10 days, infection with calflagin-depleted parasites demonstrated prolonged survival associated with a sudden decrease in parasitemia at approximately 8 days postinfection. Subsequent relapsing and remitting waves of parasitemia thereafter were associated with alternate expression of the variant surface glycoprotein, suggesting that initial clearance was antigen specific. Interestingly, despite the notable
in vivo
phenotype and flagellar localization of the calflagins,
in vitro
analysis of the calflagin-deficient parasites demonstrated normal proliferation, flagellar motility, and morphology. Further analysis of the kinetics of surface antibody clearance also did not demonstrate a deficit in the calflagin-deficient parasites; thus, the molecular basis for the altered course of infection is independent of an effect on parasite cell cycle progression, motility, or degradation of surface-bound antibodies.
NlpI Contributes to
Escherichia coli
K1 Strain RS218 Interaction with Human Brain Microvascular Endothelial Cells
Authors: Teng Ching-Hao , Tseng Yu-Ting , Maruvada Ravi , Pearce Donna , Xie Yi , Paul-Satyaseela Maneesh , Kim Kwang Sik
Published: April 2010

Escherichia coli
K1 is the most common Gram-negative bacillary organism causing neonatal meningitis.
E. coli
K1 binding to and invasion of human brain microvascular endothelial cells (HBMECs) is a prerequisite for its traversal of the blood-brain barrier (BBB) and penetration into the brain. In the present study, we identified NlpI as a novel bacterial determinant contributing to
E. coli
K1 interaction with HBMECs. The deletion of
nlpI
did not affect the expression of the known bacterial determinants involved in
E. coli
K1-HBMEC interaction, such as type 1 fimbriae, flagella, and OmpA, and the contribution of NlpI to HBMECs binding and invasion was independent of those bacterial determinants. Previous reports have shown that the
nlpI
mutant of
E. coli
K-12 exhibits growth defect at 42°C at low osmolarity, and its thermosensitive phenotype can be suppressed by a mutation on the
spr
gene. The
nlpI
mutant of strain RS218 exhibited similar thermosensitive phenotype, but additional
spr
mutation did not restore the ability of the
nlpI
mutant to interact with HBMECs. These findings suggest the decreased ability of the
nlpI
mutant to interact with HBMECs is not associated with the thermosensitive phenotype. NlpI was determined as an outer membrane-anchored protein in
E. coli
, and the
nlpI
mutant was defective in cytosolic phospholipase A
2
α (cPLA
2
α) phosphorylation compared to the parent strain. These findings illustrate the first demonstration of NlpI's contribution to
E. coli
K1 binding to and invasion of HBMECs, and its contribution is likely to involve cPLA
2
α.
The BatR/BatS Two-Component Regulatory System Controls the Adaptive Response ofBartonella henselaeduring Human Endothelial Cell Infection
Authors: Quebatte Maxime , Dehio Michaela , Tropel David , Basler Andrea , Toller Isabella , Raddatz Guenter , Engel Philipp , Huser Sonja , Schein Hermine , Lindroos Hillevi L. , Andersson Siv G. E. , Dehio Christoph
Published: April 2010

Here, we report the first comprehensive study ofBartonella henselaegene expression during infection of human endothelial cells. Expression of the main cluster of upregulated genes, comprising the VirB type IV secretion system and its secreted protein substrates, is shown to be under the positive control of the transcriptional regulator BatR. We demonstrate binding of BatR to the promoters of thevirBoperon and a substrate-encoding gene and provide biochemical evidence that BatR and BatS constitute a functional two-component regulatory system. Moreover, in contrast to the acid-inducible (pH 5.5) homologs ChvG/ChvI ofAgrobacterium tumefaciens, BatR/BatS are optimally activated at the physiological pH of blood (pH 7.4). By conservation analysis of the BatR regulon, we show that BatR/BatS are uniquely adapted to upregulate a genus-specific virulence regulon during hemotropic infection in mammals. Thus, we propose that BatR/BatS two-component system homologs represent vertically inherited pH sensors that control the expression of horizontally transmitted gene sets critical for the diverse host-associated life styles of the alphaproteobacteria.
Niphotrichum muticum (Musci, Grimmiaceae), an addition to the moss flora of the Aleutian Islands
Authors: Bednarek-Ochyra Halina , Seppelt Rodney D. , Ochyra Ryszard
Published: April 2010

Niphotrichum muticum (Kindb.) Frisvoll is recorded for the first time from the Aleutian Islands where it was collected on three islands, namely Kiska Island in the Rat Islands group, Adak Island in the Andreanof Islands group, and Unalaska Island in the Fox Islands group. The Aleutian plants are briefly described and illustrated and ecological requirements of the species are discussed. The North American and global ranges of N. muticum are reviewed and mapped.
Ecological facets of plant species rarity in rock outcrop ecosystems of the Gulf Islands, British ColumbiaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Sadler Kella D. , Bradfield Gary E.
Published: April 2010

Rare plants and their habitats are integral to the conservation of biodiversity in many areas. With increasing habitat destruction and fragmentation, there is an urgent need to identify elements of diversity that are at risk, to adequately address conservation priorities, and successfully implement management strategies. In this research project, plant species rarity in rock outcrop ecosystems occurring on the Gulf Islands in southwestern British Columbia was examined at 13 study sites (3000 m2area examined per site). Bryophytes comprised the largest portion of rare taxa; 18 of the 20 provincially rare taxa were mosses, including two species new to Canada. Challenges facing rare plant species conservation were considered from a landscape management perspective. Rock outcrops represent non-equilibrial, primary successional systems; some form of perpetual large-scale disturbance (e.g., climate and (or) grazing) may be integral to maintaining these ecosystems, their constituent habitats, and the occurrence of many rare moss species. In contrast with vascular plants, which are of focal concern in relatively deeper-soiled Garry oak meadows (i.e., native herbs and grasses), bryophytes have limited competitive ability. As such, the rare bryophytes of rock outcrop ecosystems are likely to be highly sensitive to successional development within sites (i.e., factors reducing the availability of early successional habitats) that may arise through land use modifications and (or) changes in local climatic conditions related to global warming.
The lichens and lichenicolous fungi of Haida Gwaii (Queen Charlotte Islands), British Columbia, Canada. 5. A new species of Lecanora from shoreline rocksThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Brodo Irwin M.
Published: April 2010

A species of Lecanora in the L. dispersa group, with a well-developed pale thallus and a granular epihymenium, resembling L. albescens , is found exclusively on shoreline rocks and appears to be new. It is described as Lecanora schofieldii  sp. nov., found mainly in the Pacific Northwest, but also rarely on the northeast coast. Its distinctions from similar species on shoreline rocks are given, together with a key for their identification. The first western record of L. xylophila from rocks is given.
Hypogymnia recurvaandHypogymnia wilfianaspp. nov., two new lichens from western North AmericaThis paper is one of a selection of papers published as part of the special Schofield Gedenkschrift.
Authors: Goward Trevor , Ahti Teuvo , Elix John A. , Spribille Toby
Published: April 2010

Hypogymnia metaphysodes was first described from Japan and Sakhalin, and later reported from western North America. Here we show that the North American material currently referred to H. metaphysodes differs from that species not only morphologically and chemically, but also in ascospore size and shape. We also show that the North American material is in fact heterogeneous, and can be assigned to two well-defined species here described as new: Hypogymnia recurva sp. nov. and H. wilfiana sp. nov. Both of these lichens contain distinctive secondary metabolites: vittatolic acid in the case of H. recurva, and 2-methylene-3-carboxy-18-hydroxynonadecanoic acid (“apinnatic acid”), reported here for the first time from Hypogymnia , in H. wilfiana. Both of our new species are so far known only from western North America, where they occur primarily as epiphytes on the branches of conifers. Hypogymnia metaphysodes s. str. has not yet been reliably reported from this region and should be excluded from the North American lichen flora.
ON NON-SELF-ADJOINT OPERATORS FOR OBSERVABLES IN QUANTUM MECHANICS AND QUANTUM FIELD THEORY
Authors: RECAMI ERASMO , OLKHOVSKY VLADISLAV S. , MAYDANYUK SERGEI P.
Published: April 2010

The aim of this paper is to show the possible significance, and usefulness, of various non-self-adjoint operators for suitable Observables in nonrelativistic and relativistic quantum mechanics, and in quantum electrodynamics. More specifically, this work deals with: (i) the maximal Hermitian (but not self-adjoint) time operator in nonrelativistic quantum mechanics and in quantum electrodynamics; (ii) the problem of the four-position and four-momentum operators, each one with its Hermitian and anti-Hermitian parts, for relativistic spin-zero particles. Afterwards, other physically important applications of non-self-adjoint (and even non-Hermitian) operators are discussed: in particular, (iii) we reanalyze in detail the interesting possibility of associating quasi-Hermitian Hamiltonians with (decaying) unstable states in nuclear physics. Finally, we briefly mention the cases of quantum dissipation, as well as of the nuclear optical potential.
DUAL KAPPA POINCAŔE ALGEBRA
Authors: MAGPANTAY JOSE A.
Published: April 2010

We show a different modification of Poincaré algebra that also preserves Lorentz algebra. The change begins with how boosts affect space–time in a way similar to how they affect the momenta in kappa Poincaré algebra; hence the term "dual kappa Poincaré algebra." Since by construction the new space–time commutes, it follows that the momenta cocommute. Proposing a space–time coalgebra that is similar to the momentum coproduct in the bicrossproduct basis of kappa Poincaré algebra, we derive the phase space algebra using the Heisenberg double construction. The phase space variables of the dual kappa Poincaré algebra are then related to SR phase space variables. From these relations, we complete the dual kappa Poincaré algebra by deriving the action of rotations and boosts on the momenta.