bluuebunny/crossref_metadata_2025 huggingface dataset:
Researching European ‘alternative’ food networks: some methodological considerations
Authors: Venn Laura , Kneafsey Moya , Holloway Lewis , Cox Rosie , Dowler Elizabeth , Tuomainen Helena
Published: September 2006

Recent European literature on ‘alternative’ food networks (AFNs) draws heavily upon an apparently accessible and diverse body of non‐conventional food networks in the agro‐food sector and whilst researchers frequently refer to individual examples of farmers markets, box schemes, producer cooperatives and community‐supported agriculture projects, less attention is given to the methodological processes that facilitate the identification and examination of these networks. From the preliminary stages of a research project focusing on examples of AFNs,

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this paper examines the process of operationalizing AFNs research and reviews the difficulties associated with identifying, comparing and characterizing AFNs.
The politics of toponyms in the Pamir mountains
Authors: Horsman Stuart
Published: September 2006

This paper is an original study of the relationship between landscape and ideology through an examination of Pamir mountain toponyms. The research analyses traditional, Tsarist, Soviet and post‐Soviet Pamiri toponyms. It is the first study to compare mountain toponyms with existing research on the naming processes of urban Soviet and post‐Soviet places. It also compares the Soviet political use of landscape with that by other political systems and ideologies, in particular Nazism. The paper finds that over time there are commonalities in the types of names selected for urban places and mountains and the rationale behind these choices. However, it also notes significant differences. These differences suggest that the concept of ‘the mountain’ did not carry the same political significance as the urban or other landscapes (the steppe and forest) in Russian, Soviet and post‐Soviet ideological and nation‐building constructions.
Clustering of Ventricular Tachyarrhythmias in Heart Failure Patients Implanted with a Biventricular Cardioverter Defibrillator
Authors: LUNATI MAURIZIO , GASPARINI MAURIZIO , BOCCHIARDO MARIO , CURNIS ANTONIO , LANDOLINA MAURIZIO , CARBONI ANGELO , LUZZI GIANNI , ZANOTTO GABRIELE , RAVAZZI PIERANTONIO , MAGENTA GIOVANNI , DENARO ALESSANDRA , DISTEFANO PAOLA , GRAMMATICO ANDREA ,   on behalf of the InSync ICD Italian Registry Investigators
Published: September 2006

Background: Temporal patterns of ventricular tachyarrhythmia (VT/VF) have been studied only in patients who have received implantable cardioverter defibrillators (ICD) for secondary prevention of sudden death, and mainly in ischemic patients. The aim of this study was to evaluate VT/VF recurrence patterns in heart failure (HF) patients with biventricular ICD and to stratify results according to HF etiology and ICD indication.

Methods and Results: We studied 421 patients (91% male, 66 ± 9 years). HF etiology was ischemic in 292 patients and nonischemic in 129. ICD indication was for primary prevention in 227 patients and secondary prevention in 194. Baseline left ventricular ejection fraction (LVEF) was 26 ± 7%, QRS duration 168 ± 32 msec, and NYHA class 2.9 ± 0.6. In a follow‐up of 19 ± 11 months, 1,838 VT/VF in 110 patients were appropriately detected. In 59 patients who had ≥4 episodes, we tried to determine whether VT/VF occurred randomly or rather tended to cluster by fitting the frequency distribution of tachycardia interdetection intervals with exponential functions: VT/VF clusters were observed in 46 patients (78% of the subgroup of patients with ≥4 episodes and 11% of the overall population). On multivariate logistic analysis, VT/VF clusters were significantly (P < 0.01) associated with ICD indication for secondary prevention (odds ratio [OR]= 3.12; confidence interval [CI]= 1.56–6.92), nonischemic HF etiology (OR = 4.34; CI = 2.02–9.32), monomorphic VT (OR = 4.96; CI = 2.28–10.8), and LVEF < 25% (OR = 3.34; CI = 1.54–7.23). Cardiovascular hospitalizations and deaths occurred more frequently in cluster (21/46 [46%]) than in noncluster patients (63/375 (17%), P < 0.0001).

Conclusions: In HF patients with biventricular ICDs, VT/VF clusters may be regarded as the epiphenomenon of HF deterioration or as a marker of suboptimal response to cardiac resynchronization therapy.
Quantification of Tricuspid Regurgitation by Live Three‐Dimensional Transthoracic Echocardiographic Measurements of Vena Contracta Area
Authors: Velayudhan Dasan E. , Brown Todd M. , Nanda Navin C. , Patel Vinod , Miller Andrew P. , Mehmood Farhat , Rajdev Sanjay , Fang Ligang , Frans Ebenezer E. , Vengala Srinivas , Madadi Pavan , Yelamanchili Pridhvi , Baysan Oben
Published: September 2006

We evaluated tricuspid regurgitation (TR) by multiple echocardiographic techniques in 93 consecutive patients who underwent standard two‐dimensional (2D) and live three‐dimensional (3D) transthoracic echocardiography (TTE). TR vena contracta (VC) area was obtained by 3D TTE by systematic and sequential cropping of the acquired 3D TTE dataset. Assessment of VC area by 3D TTE was compared to 2D TTE measurements of the ratio of TR regurgitant jet area to right atrial area (RJA/RAA), RJA alone, VC width, and calculated VC area. VC area from 3D TTE closely correlated with RJA/RAA and RJA alone as determined from 2D TTE measurements. Live 3D TTE color Doppler measurements of VC area can be used for quantitative assessment of TR and offer incremental value for quantification of particularly severe regurgitant lesions.
Two New Species of Symbiotic Ciliates from the Respiratory Tract of Cetaceans with Establishment of the New Genus Planilamina n. gen. (Dysteriida, Kyaroikeidae)
Authors: MA HONGWEI , OVERSTREET ROBIN M. , SNIEZEK JAMES H. , SOLANGI MOBASHIR , WAYNE COATS D.
Published: September 2006

ABSTRACT. Examination of mucus discharged from the blowhole of Atlantic bottlenose dolphin (Tursiops truncatus) at Marine Life Oceanarium, Gulfport, Mississippi, and false killer whale (Pseudorca crassidens) and Atlantic bottlenose dolphin at SeaWorld Orlando, Orlando, Florida, using live observations and protargol impregnation revealed mixed infections of Kyaroikeus cetarius and two new species. Planilamina n. gen. is characterized by a C‐shaped argentophilic band located along the laterally flattened margin of cell and extending from the cell apex to subposterior cone‐shaped podite; a deep oral cavity containing one short preoral kinety, two circumoral kineties, seven to 13 infundibular kineties, and a cytostome; a broadly funnel‐shaped cytopharynx reinforced by argentophilic fibers but without nematodesmata; closely packed postoral kinetofragments set in a pocket located anterior left of the podite; and somatic kineties as a right field closely situated at the right surface and a left field bordering the anterior left margin of the oral cavity. The type species for the genus, Planilamina ovata n. sp., is distinguished from its sister species Planilamina magna n. sp. by the following characteristics: body size (28–65 × 20–43 μm vs. 57–90 × 40–63 μm), number of right field kineties (38–55 vs. 79–99), and position of the anterior end of the leftmost kinety in the right somatic field (anterior one‐third vs. mid‐body). The morphogenesis of Planilamina ovata is similar to that of K. cetarius. The diagnosis of Kyaroikeidae is emended to accommodate the new genus.
Phylogenetic Distance of Thelohania butleriJohnston, Vernick, and Sprague, 1978 (Microsporidia; Thelohaniidae), a Parasite of the Smooth Pink Shrimp Pandalus jordani, from its Congeners Suggests Need for Major Revision of the Genus Thelohania Henneguy, 1892
Authors: BROWN AMANDA M. V. , ADAMSON MARTIN L.
Published: September 2006

ABSTRACT. Thelohania butleri, a microsporidian that causes mortality and commercial losses in the smooth pink shrimp Pandalus jordani, is of taxonomic interest as a species resembling the poorly studied type species, Thelohania giardi, of the large, polyphyletic genus Thelohania. We examined the ultrastructure of T. butleri to confirm its identity and reconstructed phylogenies using ribosomal DNA to find the relationship of T. butleri with other Thelohania species in crayfish and ants. Light and transmission electron microscopy from specimens collected from the type locality, the Pacific coast of Canada, confirmed the identity and demonstrated a development similar to that of T. giardi, involving a series of binary fissions without formation of a plasmodium. Phylogenetic analyses consistently showed T. butleri to be distantly related to other Thelohania species, and closely related to species from marine decapods within a larger fish‐parasitic clade. Together, features such as host group and habitat, developmental morphology, and phylogeny suggest T. butleri may be a closer relative to T. giardi than any other Thelohania species represented by DNA data so far, and thus imply species from crayfish and ants may not belong in this genus. Results also confirm that genus Thelohania and family Thelohanidae are in need of revision.
Glycodelin: a novel serum anti‐inflammatory marker in type 1 diabetic retinopathy during pregnancy
Authors: Loukovaara Sirpa , Immonen Ilkka R. J. , Loukovaara Mikko J. , Koistinen Riitta , Kaaja Risto J.
Published: September 2006

Purpose:  Inflammation may play a role in the development of diabetic retinopathy during pregnancy. Glycodelin is a glycoprotein whose secretion from the endometrial glands increases during pregnancy. Glycodelin has immunosuppressive properties thought to play a role in the protection of the fetoplacental unit. We studied the role of glycodelin in the development and progression of retinopathy in type 1 diabetes during pregnancy.

Methods:  Retinopathy was graded from fundus photographs in 45 diabetes subjects and nine non‐diabetes subjects prospectively during pregnancy. Serum glycodelin concentration was measured by an immunofluorometric assay.

Results:  In women with diabetes with progression of retinopathy, serum glycodelin concentration was 263 ng/ml (range 116–505 ng/ml) during the first trimester, 61 ng/ml (range 30–106 ng/ml) during the second trimester, and 29 ng/ml (range 13–53 ng/ml) during the third trimester, compared with values of 595 ng/ml (range 376–870 ng/ml), 104 ng/ml (range 75–228 ng/ml) and 45 ng/ml (range 32–74 ng/ml), respectively, in diabetes subjects without progression (p = 0.005 between the groups). Low glycodelin concentration was associated with progression of diabetic retinopathy in multiple regression analysis. Serum glycodelin concentration was similar in women with and without diabetes throughout pregnancy (p = 0.63 by repeated measures anova).

Conclusions:  Low glycodelin concentration is associated with progression of retinopathy in pregnant women with diabetes. A possible causal relationship between low glycodelin levels and progression of retinopathy may be mediated by the immunomodulatory properties of glycodelin.
High glucose‐boosted inflammatory responses to lipopolysaccharide are suppressed by statin
Authors: Nareika A. , Maldonado A. , He L. , Game B. A. , Slate E. H. , Sanders J. J. , London S. D. , Lopes‐Virella M. F. , Huang Y.
Published: September 2006

Background and Objective:  It has been established that periodontal diseases are more prevalent and of greater severity in diabetic patients than in nondiabetic patients. Recent studies have underscored the role of monocytes and macrophages in periodontal tissue inflammation and destruction in diabetic patients. Although it has been shown that monocytes isolated from diabetic patients produce more inflammatory cytokines and that gingival crevicular fluid collected from diabetic patients contains higher levels of inflammatory cytokines than that obtained from nondiabetic patients, the underlying mechanisms are not well understood.

Material and Methods:  U937 histiocytes cultured in medium containing either normal (5 mM) or high (25 mM) glucose were treated with 100 ng/ml of lipopolysaccharide for 24h. After the treatment, cytokines in the medium and cytokine mRNA in the cells were quantified using enzyme‐linked immunosorbet assay and real‐time polymerase chain reaction, respectively.

Results:  In this study, we demonstrated that the pre‐exposure of U937 histiocytes to high glucose concentrations markedly increased the lipopolysaccharide‐induced secretion of pro‐inflammatory cytokines and chemokines and the cellular inducible nitric oxide level compared with pre‐exposure to normal glucose. Our data also showed that the increased secretion of cytokines was a result of increased mRNA expression. Furthermore, the effects of statin and peroxisome proliferators‐activated receptor agonists on high glucose‐enhanced secretion of cytokines were determined. The results showed that simvastatin, but not fenofibrate or pioglitazone, inhibited high glucose‐enhanced cytokine release.

Conclusion:  This study has shown that high glucose concentrations and lipopolysaccharide act synergistically to stimulate the secretion of inflammatory mediators, and that statin is capable of suppressing the high glucose‐boosted proinflammatory response. This study therefore delineates a novel mechanism by which hyperglycemia enhances the inflammatory responses of macrophages and suggests that statin may be useful in the treatment of periodontal disease in diabetic patients.
Estimating a boundary line model for a biological response by maximum likelihood
Authors: Milne A.E. , Ferguson R.B. , Lark R.M.
Published: September 2006

The boundary line model was proposed to interpret biological data sets, where one variable is a biological response (e.g. crop yield) to an independent variable (e.g. available water content of the soil). The upper (or lower) boundary on a plot of the dependent variable (ordinate) against the independent variable (abscissa) represents the limiting response of the dependent variable to the independent variable value. Although the concept has been widely used, the methods proposed to define the boundary line have been subject to criticism. This is because of their ad hoc nature and lack of theoretical basis. In this article, we present a novel method for fitting the boundary line to a set of data. The method uses a censored probability distribution to interpret the data structure. The parameters of the distribution (and hence the boundary line parameters) are fitted using maximum likelihood and related confidence intervals deduced. The method is demonstrated using both simulated and real data sets.
INFLUENCE OF CHEWING AND SWALLOWING BEHAVIOR ON VOLATILE RELEASE IN TWO CONFECTIONERY SYSTEMS
Authors: BLISSETT A. , HORT J. , TAYLOR A.J.
Published: September 2006

Electromyography, electroglottography and turbine airflow technology were used to characterize the chewing, swallowing and breath flow profiles of 35 subjects during the consumption of two different (a gum Arabic‐ and carrageenan‐based) confectionery chews. Simultaneous volatile release measurements were obtained using atmospheric pressure chemical ionization mass spectrometry. Subgroups of subjects displaying different eating characteristics were identified for both products. Parameters accounting for the maximum variance (product 1, 42% and product 2, 52%) between the subgroups were chewing force, chewing rate, proportion of work and total number of chews. Volatile release measurements were significantly different between the subgroups from product 1. The impact of the different eating characteristics on volatile release from product 2 was less defined, and postulated to be a result of the contrasting textural properties. Manipulating in vivo breakdown of chewy confectionery products, by texture modification, may influence consumer's volatile release and subsequent flavor perception.
COLD GELATION OF WHEY PROTEIN EMULSIONS
Authors: ROSA PAULA , SALA GUIDO , VAN VLIET TON , VAN DE VELDE FRED
Published: September 2006

Stable and homogeneous emulsion‐filled gels were prepared by cold gelation of whey protein isolate (WPI) emulsions. A suspension of heat‐denatured WPI (soluble WPI aggregates) was mixed with a 40% (w/w) oil‐in‐water emulsion to obtain gels with varying concentrations of WPI aggregates and oil. For emulsions stabilized with native WPI, creaming was observed upon mixing of the emulsion with a suspension of WPI aggregates, likely as a result of depletion flocculation induced by the differences in size between the droplets and aggregates. For emulsions stabilized with soluble WPI aggregates, the obtained filled suspension was stable against creaming, and homogeneous emulsion‐filled gels with varying protein and oil concentrations were obtained. Large deformation properties of the emulsion‐filled cold‐set WPI gels were determined by uniaxial compression. With increasing oil concentration, the fracture stress increases slightly, whereas the fracture strain decreases slightly. Small deformation properties were determined by oscillatory rheology. The storage modulus after 16 h of acidification was taken as a measure of the gel stiffness. Experimental results were in good agreement with predictions according to van der Poel's theory for the effect of oil concentration on the stiffness of filled gels. Especially, the influence of the modulus of the matrix on the effect of the oil droplets was in good agreement with van der Poel's theory.
DIRECTION REVERSALS IN THE MECHANICAL SIGNATURE OF CELLULAR SNACKS: A MEASURE OF BRITTLENESS?
Authors: CORRADINI MARIA G. , PELEG MICHA
Published: September 2006

ABSTRACTS

The “mechanical signatures” of brittle cellular foods are known to be irregular and irreproducible. Nevertheless, their degree of jaggedness is remarkably similar and can be a measure of such foods' brittleness and perceived crunchiness/crispiness. An irregular curve's “jaggedness” is manifested by frequent direction reversals. Hence, their number can serve as a jaggedness's index. Counting the number of direction reversals in a digitized force‐displacement curve can be done with a simple algorithm, implemented in any general‐purpose software. The number of direction reversals is strongly correlated with the signature's apparent fractal dimension. It is also a reproducible enough parameter to monitor the loss of brittleness in snacks as a result of moisture sorption. This measure of jaggedness, however, is inapplicable to smooth force‐displacement curves because in such records, the small random force fluctuations produced by the digitizing process can create a false impression of “jaggedness.” Although a correction for this artifact can be introduced into the program, its utility is doubtful.
The emerging role of neuronal nitric oxide synthase in the regulation of myocardial function
Authors: Casadei Barbara
Published: September 2006

The recent discovery of a NOS1 gene product (i.e. a neuronal‐like isoform of nitric oxide synthase or nNOS) in the mammalian left ventricular (LV) myocardium has provided a new key for the interpretation of the complex experimental evidence supporting a role for myocardial constitutive nitric oxide (NO) production in the regulation of basal and β‐badrenergic cardiac function. Importantly, nNOS gene deletion has been associated with more severe LV remodelling and functional deterioration in murine models of myocardial infarction, suggesting that nNOS‐derived NO may also be involved in the myocardial response to injury. To date, the mechanisms by which nNOS influences myocardial pathophysiology remain incompletely understood. In particular, it seems over simplistic to assume that all aspects of the myocardial phenotype of nNOS knockout (nNOS−/−) mice are a direct consequence of lack of NO production from this source. Emerging data showing co‐localisation of xanthine oxidoreductase (XOR) and nNOS in the sarcoplasmic reticulum of rodents, and increased XOR activity in the nNOS−/− myocardium, suggest that nNOS gene deletion may have wider implications on the myocardial redox state. Similarly, the mechanisms regulating the targeting of myocardial nNOS to different subcellular compartments and the functional consequences of intracellular nNOS trafficking have not been fully established. Whether this information could be translated into a better understanding and management of human heart failure remains the most important challenge for future investigations.
Vascular endothelial growth factor mRNA and protein do not change in parallel during non‐inflammatory skeletal muscle ischaemia in rat
Authors: Milkiewicz Malgorzata , Hudlicka Olga , Shiner Ruth , Egginton Stuart , Brown Margaret D.
Published: September 2006

Impaired blood flow is thought to induce a pro‐angiogenic environment due to local hypoxia, yet prolonged mild ischaemia induces only modest capillary growth. We compared the expression of vascular endothelial growth factor (VEGF) mRNA and protein with capillary to fibre ratio (C: F) and muscle blood flow in extensor digitorum longus of rats that had undergone unilateral ligation of the common iliac artery. Resting blood flow during the first two weeks after ligation (3, 7 and 14 days) was decreased by ∼60% but recovered partially after 5 weeks (36% reduction). Functional hyperaemia (9‐fold increase in blood flow during contractions) was eliminated in the first week after ligation, with a moderate recovery seen after 14 and 35 days. Muscle histology confirmed the absence of tissue necrosis or inflammation. Both VEGF mRNA (60%, P < 0.05) and protein levels (700%, P < 0.01) increased during the initial phase of ischaemia (at 1 and 3 days), well before any overt angiogenesis, and both declined towards control levels by 7 days. A secondary increase in VEGF protein (by 60% at 14 days, P < 0.05) preceded the 20% increase in C: F seen after 5 weeks, but occurred while VEGF transcript levels continued to decline (to 50% of control at 35 days, P < 0.05). Thus, evaluation of neither VEGF mRNA nor protein is an adequate index of angiogenic potential in response to ischaemia. We conclude that VEGF alone is insufficient to induce angiogenesis in ischaemic conditions, and that effective angiotherapy requires intervention aimed at other cytokines.
Pacemaker phase shift in the absence of neural activity in guinea‐pig stomach: a microelectrode array study
Authors: Nakayama Shinsuke , Shimono Ken , Liu Hong‐Nian , Jiko Hideyasu , Katayama Noburu , Tomita Tadao , Goto Kazunori
Published: September 2006

Gastrointestinal (GI) motility is well organized. GI muscles act as a functional syncytium to achieve physiological functions under the control of neurones and pacemaker cells, which generate basal spontaneous pacemaker electrical activity. To date, it is unclear how spontaneous electrical activities are coupled, especially within a micrometre range. Here, using a microelectrode array, we show a spatio‐temporal analysis of GI spontaneous electrical activity. The muscle preparations were isolated from guinea‐pig stomach, and fixed in a chamber with an array of 8 × 8 planar multielectrodes (with 300 μm in interpolar distance). The electrical activities (field potentials) were simultaneously recorded through a multichannel amplifier system after high‐pass filtering at 0.1 Hz. Dihydropyridine Ca2+ channel antagonists are known to differentiate the electrical pacemaker activity of interstitial cells of Cajal (ICCs) by suppressing smooth muscle activity. In the presence of nifedipine, we observed spontaneous electrical activities that were well synchronized over the array area, but had a clear phase shift depending on the distance. The additional application of tetrodotoxin (TTX) had little effect on the properties of the electrical activity. Furthermore, by constructing field potential images, we visualized the synchronization of pacemaker electrical activities resolving phase shifts that were measurable over several hundred micrometres. The results imply a phase modulation mechanism other than neural activity, and we postulate that this mechanism enables smooth GI motility. In addition, some preparations clearly showed plasticity of the pacemaker phase shift.
Stoichiometry of a pore mutation that abolishes picrotoxin‐mediated antagonism of the GABAA receptor
Authors: Sedelnikova Anna , Erkkila Brian E. , Harris Holly , Zakharkin Stanislav O. , Weiss David S.
Published: September 2006

Picrotoxin, a potent antagonist of the inhibitory central nervous system GABAA and glycine receptors, is believed to interact with residues that line the central ion pore. These pore‐lining residues are in the second transmembrane domain (TM2) of each of the five constituent subunits. One of these amino acids, a threonine at the 6′ location, when mutated to phenylalanine, abolishes picrotoxin sensitivity. It has been suggested that this threonine, via hydrogen bonding, directly interacts with the picrotoxin molecule. We previously demonstrated that this mutation, in the α, β or γ subunit, can impart picrotoxin resistance to the GABA receptor. Since the functional pentameric GABA receptor contains two α subunits, two β subunits and one γ subunit, it is not clear how many α and β subunits must carry this mutation to impart the resistant phenotype. In this study, by coexpression of mutant α or β subunits with their wild‐type counterparts in various defined ratios, we demonstrate that any single subunit carrying the 6′ mutation imparts picrotoxin resistance. Implications of this finding in terms of the mechanism of antagonism are considered.
Dynamic Modeling of Belt Drive Systems: Effects of the Shear Deformations
Authors: Tonoli Andrea , Amati Nicola , Zenerino Enrico
Published: September 2006

Multiribbed serpentine belt drive systems are widely adopted in accessory drive automotive applications due to the better performances relative to the flat or V-belt drives. Nevertheless, they can generate unwanted noise and vibration which may affect the correct functionality and the fatigue life of the belt and of the other components of the transmission. The aim of the paper is to analyze the effect of the shear deflection in the rubber layer between the pulley and the belt fibers on the rotational dynamic behavior of the transmission. To this end the Firbank’s model has been extended to cover the case of small amplitude vibrations about mean rotational speeds. The model evidences that the shear deflection can be accounted for by an elastic term reacting to the torsional oscillations in series with a viscous term that dominates at constant speed. In addition, the axial deformation of the belt spans are taken into account. The numerical model has been validated by the comparison with the experimental results obtained on an accessory drive transmission including two pulleys and an automatic tensioner. The results show that the first rotational modes of the system are dominated by the shear deflection of the belt.
Panel Flutter Model Identification Using the Minimum Model Error Method on the Forced Response Measurements
Authors: Shiryayev Oleg V. , Slater Joseph C.
Published: September 2006

This work illustrates application of the minimum model error system identification method to obtain the nonlinear state space models of a fluttering panel. Identification using position and velocity data from forced response of the panel is presented here. The response was numerically simulated using two different discretization approaches: through finite differences and using the Galerkin’s method. Data from two different parts of response time history were considered. First, data where transients due to initial conditions and the forcing were present were used for identification. Then, data when only transients due to forcing were present were used for identification. The models obtained using the forced response of the panel were able to capture the behavior of the true system relatively accurately. Identification of models of different sizes is also discussed. Reduced size models can be successfully created from the forced response data using the minimum model error method. It is demonstrated that the number of degrees of freedom in the model attempted to be identified should be consistent with the number modes observed in the measurements. The response surface method was successfully applied to generate models for various flow regimes.
Reducing the Impact of Measurement Errors When Reconstructing Spatial Dynamic Forces
Authors: Liu Yi , Shepard W. Steve
Published: September 2006

Inferring external spatially distributed dynamic forces from measured structural responses is necessary when direct measurement of these forces is not possible. The finite difference method and the modal method have been previously developed for reconstructing these forces. However, the accuracy of these methods is often hindered due to the amplification of measurement errors in the computation process. In order to analyze these error amplification effects by using the singular value decomposition approach, the mathematic expressions for these two force reconstruction methods are first transformed into a certain linear system of equations. Then, a regularization method, the Tikhonov method, is applied to increase computational stability. In order to achieve a good regularized result, the L-curve method is used in conjunction with the Tikhonov method. The effectiveness in reducing the influence of the measurement errors when applying the regularization method to the finite difference method and the modal method is investigated analytically and numerically. It is found that when the regularization method is appropriately applied, reliable computational results for the reconstructed force can be achieved.
Dynamic Behavior of an AMB/Supported Rotor Subject to Parametric Excitation
Authors: Amer Y. A. , Eissa M. H. , Hegazy U. H. , Sabbah A. S.
Published: September 2006

The dynamical behavior of a parametrically excited simple rigid disk-rotor supported by active magnetic bearings (AMB) is investigated, without gyroscopic effects. The principal parametric resonance case is considered and studied. The motion of the rotor is modeled by a coupled second-order nonlinear ordinary differential equations. Their approximate solutions are sought applying the method of multiple scales. A reduced system of four first-order ordinary differential equations are determined to describe the time variation of the amplitudes and phases of the vibration in the horizontal and vertical directions. The steady-state response and the stability of the solutions for various parameters are studied numerically, using the frequency response function method. The numerical results show that the system behavior includes multiple solutions, jump phenomenon, and sensitive dependence on initial conditions. It is also shown that the system parameters have different effects on the nonlinear response of the rotor. Results are compared to previously published work.
Numerical Simulation of Noninvasive Blood Pressure Measurement
Authors: Hayashi Satoru , Hayase Toshiyuki , Shirai Atsushi , Maruyama Masaru
Published: September 2006

In this paper, a simulation model based on the partially pressurized collapsible tube model for reproducing noninvasive blood pressure measurement is presented. The model consists of a collapsible tube, which models the pressurized part of the artery, rigid pipes connected to the collapsible tube, which model proximal and distal region far from the pressurized part, and the Windkessel model, which represents the capacitance and the resistance of the distal part of the circulation. The blood flow is simplified to a one-dimensional system. Collapse and expansion of the tube is represented by the change in the cross-sectional area of the tube considering the force balance acting on the tube membrane in the direction normal to the tube axis. They are solved using the Runge-Kutta method. This simple model can easily reproduce the oscillation of inner fluid and corresponding tube collapse typical for the Korotkoff sounds generated by the cuff pressure. The numerical result is compared with the experiment and shows good agreement.
Laminar Airflow and Nanoparticle or Vapor Deposition in a Human Nasal Cavity Model
Authors: Shi H. , Kleinstreuer C. , Zhang Z.
Published: September 2006

The transport and deposition of nanoparticles, i.e., dp=1–2nm, or equivalent vapors, in the human nasal cavities is of interest to engineers, scientists, air-pollution regulators, and healthcare officials alike. Tiny ultrafine particles, i.e., dp≤5nm, are of special interest because they are most rapidly absorbed and hence have an elevated toxic or therapeutic impact when compared to larger particles. Assuming transient laminar 3-D incompressible flow in a representative human nasal cavity, the cyclic airflow pattern as well as local and overall nanoparticle depositions were computationally simulated and analyzed. The focus was on transient effects during inhalation/exhalation as compared to the steady-state assumption typically invoked. Then, an equation for a matching steady-state inhalation flow rate was developed that generates the same deposition results as cyclic inhalation. Of special interest is the olfactory region where the narrow channel surfaces receive only about one-half of a percent of the inhaled nanoparticles because the airflow bypasses these recesses located in the superior-most portions in the geometrically complex nasal cavities.
Effects of Stent Design Parameters on Normal Artery Wall Mechanics
Authors: Bedoya Julian , Meyer Clark A. , Timmins Lucas H. , Moreno Michael R. , Moore James E.
Published: September 2006

A stent is a device designed to restore flow through constricted arteries. These tubular scaffold devices are delivered to the afflicted region and deployed using minimally invasive techniques. Stents must have sufficient radial strength to prop the diseased artery open. The presence of a stent can subject the artery to abnormally high stresses that can trigger adverse biologic responses culminating in restenosis. The primary aim of this investigation was to investigate the effects of varying stent “design parameters” on the stress field induced in the normal artery wall and the radial displacement achieved by the stent. The generic stent models were designed to represent a sample of the attributes incorporated in present commercially available stents. Each stent was deployed in a homogeneous, nonlinear hyperelastic artery model and evaluated using commercially available finite element analysis software. Of the designs investigated herein, those employing large axial strut spacing, blunted corners, and higher amplitudes in the ring segments induced high circumferential stresses over smaller areas of the artery’s inner surface than all other configurations. Axial strut spacing was the dominant parameter in this study, i.e., all designs employing a small stent strut spacing induced higher stresses over larger areas than designs employing the large strut spacing. Increasing either radius of curvature or strut amplitude generally resulted in smaller areas exposed to high stresses. At larger strut spacing, sensitivity to radius of curvature was increased in comparison to the small strut spacing. With the larger strut spacing designs, the effects of varying amplitude could be offset by varying the radius of curvature and vice versa. The range of minimum radial displacements from the unstented diastolic radius observed among all designs was less than 90μm. Evidence presented herein suggests that stent designs incorporating large axial strut spacing, blunted corners at bends, and higher amplitudes exposed smaller regions of the artery to high stresses, while maintaining a radial displacement that should be sufficient to restore adequate flow.
Comparison of Element Technologies for Modeling Stent Expansion
Authors: Hall Garrett J. , Kasper Eric P.
Published: September 2006

Numerical analysis has become a standard, and in fact required, component of the process in which new biomedical stent devices are designed and approved. Despite this, very little work has been performed comparing the efficiency of various numerical techniques currently available to the analyst. The present paper begins this study by comparing the computational efficiency and results achieved using various element technologies in the context of stent deployment simulations. The findings indicate that the methodologies most commonly adopted in the present literature/industrial practice are in many cases less than optimal with regard to computational efficiency.
Wetland Sedimentation from Hurricanes Katrina and Rita
Authors: Turner R. Eugene , Baustian Joseph J. , Swenson Erick M. , Spicer Jennifer S.
Published: September 2006

More than 131 × 10
6
metric tons (MT) of inorganic sediments accumulated in coastal wetlands when Hurricanes Katrina and Rita crossed the Louisiana coast in 2005, plus another 281 × 10
6
MT when accumulation was prorated for open water area. The annualized combined amount of inorganic sediments per hurricane equals (i) 12% of the Mississippi River's suspended load, (ii) 5.5 times the inorganic load delivered by overbank flooding before flood protection levees were constructed, and (iii) 227 times the amount introduced by a river diversion built for wetland restoration. The accumulation from hurricanes is sufficient to account for all the inorganic sediments in healthy saltmarsh wetlands.
Odorant ReceptorDerived cAMP Signals Direct Axonal Targeting
Authors: Imai Takeshi , Suzuki Misao , Sakano Hitoshi
Published: September 2006

In mammals, odorant receptors (ORs) direct the axons of olfactory sensory neurons (OSNs) toward targets in the olfactory bulb. We show that cyclic adenosine monophosphate (cAMP) signals that regulate the expression of axon guidance molecules are essential for the OR-instructed axonal projection. Genetic manipulations of ORs, stimulatory G protein, cAMP-dependent protein kinase, and cAMP response element–binding protein shifted the axonal projection sites along the anteriorposterior axis in the olfactory bulb. Thus, it is the OR-derived cAMP signals, rather than direct action of OR molecules, that determine the target destinations of OSNs.
Control of Peripheral Nerve Myelination by the ß-Secretase BACE1
Authors: Willem Michael , Garratt Alistair N. , Novak Bozidar , Citron Martin , Kaufmann Steve , Rittger Andrea , DeStrooper Bart , Saftig Paul , Birchmeier Carmen , Haass Christian
Published: September 2006

Although BACE1 (beta-site amyloid precursor protein–cleaving enzyme 1) is essential for the generation of amyloid-b peptide in Alzheimer's disease, its physiological function is unclear. We found that very high levels of BACE1 were expressed at time points when peripheral nerves become myelinated. Deficiency of BACE1 resulted in the accumulation of unprocessed neuregulin 1 (NRG1), an axonally expressed factor required for glial cell development and myelination.
BACE1
–/–
mice displayed hypomyelination of peripheral nerves and aberrant axonal segregation of small-diameter afferent fibers, very similar to that seen in mice with mutations in type III NRG1 or Schwann cell–specific ErbB2 knockouts. Thus, BACE1 is required for myelination and correct bundling of axons by Schwann cells, probably through processing of type III NRG1.
Medial epicondylitis: is ultrasound guided autologous blood injection an effective treatment?
Authors: Suresh S P , Ali K E , Jones H , Connell D A
Published: September 2006

Objective:To assess if ultrasound guided autologous blood injection is an effective treatment for medial epicondylitis.

Methods:Twenty patients (13 men, 7 women) with refractory medial epicondylitis with symptom duration of 12 months underwent sonographic evaluation. Tendinosis was confirmed according to three sonographic criteria: echo texture, interstitial tears and neovascularity. The tendon was then dry needled and autologous blood was injected. Patients were reviewed at 4 weeks and at 10 months. VAS scores and modified Nirschl scores were assessed pre-procedure and post-procedure.

Results:There was significant reduction in VAS pain score between pre-procedure and 10 months post-procedure when it had a median (IQR) of 1.00 (1–1.75), range 0–7. The median (IQR) Nirschl score, which at pre-procedure was 6.00 (5–7), range 4–7, had decreased at 4 weeks to 4.00 (2.25–5), range 2–7, and at 10 months to 1.00 (1–1.75), range 0–7, revealing a significant decrease (z = 3.763, p<0.001). The hypo-echoic change in the flexor tendon significantly decreased between pre-procedure, when there was a mean (SD) of 6.45 (1.47), and at 10 months, when it was 3.85 (2.37) (p<0.001). Doppler ultrasound showed that neovascularity decreased between pre-procedure, when there was a mean (SD) of 6.10 (1.62), range 4–9, and at 10 months, when it was 3.60 (2.56), range 0–9 (p<0.001).

Discussion:The combined action of dry needling and autologous blood injection under ultrasound guidance appears to be an effective treatment for refractory medial epicondylitis as demonstrated by a significant decrease in VAS pain and a fall in the modified Nirschl scores.
Polymorphisms in theHBBgene relate to individual cardiorespiratory adaptation in response to endurance training
Authors: He Z , Hu Y , Feng L , Lu Y , Liu G , Xi Y , Wen L , Xu X , Xu K
Published: September 2006

Objective:The crucial role of haemoglobin in endurance performance has been well documented. We examined whether polymorphisms in theHBBgene modified aerobic capacity.

Methods:102 recruits were trained by running 5000 m three times per week for 18 weeks. Exercise intensity progressively increased from an initial heart rate corresponding to 95% of the individual baseline ventilatory threshold during the first 10 weeks to 105% during the last 8 weeks. The phenotypes measured were running economy and VO2max. Running economy was determined by measuring submaximal VO2for 5 min at a constant running speed of 12 km·h−1and VO2max was obtained during an incremental test to exhaustion. Genomic DNA was extracted from white cells of peripheral blood and the −551C/T, intron2,+16C/G and +340 A/T genotypes were examined relative to the TAA site variants by PCR-RFLP.

Results:Genotype distributions were in Hardy-Weinberg equilibrium at three loci. None of the running economy and VO2max-related traits were associated with the three polymorphisms or haplotypes at baseline, while the training response of running economy was associated with −551C/T and intron2,+16C/G polymorphisms. Subjects homozygous for intron2,+16C/C or −551C/C had decreased oxygen cost of running compared to the other individuals.

Discussion:It was concluded that the −551C/C or intron2,+16C/C genotype might explain part of the individual variation in the cardiorespiratory adaptation to endurance training.
Transcriptional regulation by insulin: from the receptor to the geneThis paper is one of a selection of papers published in this Special issue, entitled Second Messengers and Phosphoproteins—12th International Conference.
Authors: Mounier Catherine , Posner Barry I.
Published: September 2006

Insulin, after binding to its receptor, regulates many cellular processes and the expression of several genes. For a subset of genes, insulin exerts a negative effect on transcription; for others, the effect is positive. Insulin controls gene transcription by modifying the binding of transcription factors on insulin-response elements or by regulating their transcriptional activities. Different insulin-signaling cascades have been characterized as mediating the insulin effect on gene transcription. In this review, we analyze recent data on the molecular mechanisms, mostly in the liver, through which insulin exerts its effect. We first focus on the key transcription factors (viz. Foxo, sterol-response-element-binding protein family (SREBP), and Sp1) involved in the regulation of gene transcription by insulin. We then present current information on the way insulin downregulates and upregulates gene transcription, using as examples of downregulation phosphoenolpyruvate carboxykinase (PEPCK) and insulin-like growth factor binding protein 1 (IGFBP-1) genes and of upregulation the fatty acid synthase and malic enzyme genes. The last part of the paper focuses on the signaling cascades activated by insulin in the liver, leading to the modulation of gene transcription.
ETBreceptor dependent alteration in aortic responses to ET-1 in the cardiomyopathic hamsterThis paper is one of a selection of papers published in this Special issue, entitled Second Messengers and Phosphoproteins—12th International Conference.
Authors: Al-Khoury Johny , Bkaily Ghassan , Chahine Mirna , Jacques Danielle , D'Orléans-Juste Pedro
Published: September 2006

The aim of this study was to verify whether an alteration in the aortic endothelin-1 (ET-1) response takes place in UM-X7.1 cardiomyopathic hamsters. Our results showed that ET-1 (10−12– 10−5 mol/L) induces dose-dependent sustained increases in tension in the intact and endothelium denuded aortas from both normal and cardiomyopathic hamsters. The EC50values of ET-1 of both intact and endothelium denuded aortas of normal hamsters were similar (2.2 × 10−9 mol/L and 1.8 × 10−9 mol/L, respectively). However, in cardiomyopathic hamsters, the EC50of ET-1 in intact aortas was higher (1.5 × 10−8 mol/L) than that of the endothelium denuded preparations (2.7 × 10−9 mol/L). The EC50of ET-1 in normal and cardiomyopathic hamster denuded aortas were similar. However, the EC50of ET-1 in intact aortas of cardiomyopathic hamster was higher (1.5 × 10−8 mol/L) than that of normal hamsters (2.2 × 10−9 mol/L). Pre-treatment with the ETAreceptor antagonist ABT-627 (10−5 mol/L) of intact and endothelium denuded aortas from both normal and cardiomyopathic hamsters significantly prevented ET-1 (10−7 mol/L) from inducing an increase in tension. Pre-treatment with the ETBreceptor antagonist A-192621 (10−5 mol/L) had no effect on the ET-1-induced increase in tension in endothelium denuded aortas of both normal and cardiomyopathic hamsters, as well as in intact preparations of normal animals. However, blockade of the ETBreceptors in intact aortas of cardiomyopathic hamsters significantly (p < 0.001) potentiated the ET-1-induced increase in tension. In summary, an attenuation of the contraction response to ET-1 was found in UM-X7.1 cardiomyopathic hamsters when compared with normal age-matched hamsters. This alteration of the ET-1 effect in the aortas of cardiomyopathic hamsters seems to be dependent on the presence of the endothelium and could be due, in part, to an increase in the contribution of endothelial ETBreceptors to relaxation, which in turn acts as a physiological depressor of ET-1 vasoconstriction. Our results suggest that an increase in the endothelium ETBreceptor density may play a role in the development of hypotension in UM-X7.1 cardiomyopathic hamsters.
Roles of nuclear NPY and NPY receptors in the regulation of the endocardial endothelium and heart functionThis paper is one of a selection of papers published in this Special issue, entitled Second Messengers and Phosphoproteins—12th International Conference.
Authors: Jacques Danielle , Sader Sawsan , Perreault Claudine , Abdel-Samad Dima , Provost Chantale
Published: September 2006

It is now well accepted that the heart is a multifunctional organ in which endothelial cells, and more particularly endocardial endothelial cells (EECs), seem to play an important role in regulating and maintaining cardiac excitation–contraction coupling. Even if major differences exist between vascular endothelial cells (VECs) and EECs, all endothelial cells including EECs release a variety of auto- and paracrine factors such as nitric oxide, endothelin-1, angiotensin II, and neuropeptide Y. All these factors were reported to affect cardiomyocyte contractile performance and rhythmicity. In this review, findings on the morphology of EECs, differences between EECs and other types of endothelial cells, interactions between EECs and the adjacent cardiomyocytes, and effects of NPY on the heart will be presented. We will also show evidence on the presence and localization of NPY and the Y1receptor in the endocardial endothelium and discuss their role in the regulation of cytosolic and nuclear free calcium.