bluuebunny/crossref_metadata_2025 huggingface dataset:
Enamel matrix derivative versus guided tissue regeneration in the presence of nicotine: a histomorphometric study in dogs
Authors: Pimentel Suzana Peres , Sallum Antonio Wilson , Saldanha Juliana Bezerra , Casati Márcio Zaffalon , Nociti Francisco H. , Sallum Enilson A.
Published: September 2006

Aim: The goal of this histometric study was to compare the healing process of dehiscence‐type defects treated by enamel matrix derivative (EMD) or guided tissue regeneration (GTR) under the effect of nicotine in the dog model.

Materials and Methods: Eight mongrel dogs were used. Buccal osseous dehiscences were surgically created on the mesial roots of the mandibular third and fourth pre‐molars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: open flap debridement (OFD), EMD or GTR with a resorbable membrane. During 4 months, the dogs received subcutaneous administration of nicotine (2 mg/kg twice a day with a 12 h interval between the applications). After this period, the animals were killed and the blocks were processed. The histometric parameters evaluated included gingival recession, epithelial length, connective tissue adaptation, new cementum and new bone.

Results: A superior length of new cementum was observed in the sites treated by EMD in comparison with OFD (p0.05). No statistically significant differences were observed between GTR and the other groups.

Conclusions: In the presence of nicotine, EMD may promote more new cementum formation than OFD while GTR failed to provide a significant difference.
Extinction of a weakly armoured threespine stickleback (Gasterosteus aculeatus) population in Prator Lake, Alaska
Authors: Patankar R. , Von Hippel F. A. , Bell M. A.
Published: September 2006

Abstract – Threespine stickleback (Gasterosteus aculeatus) samples from Prator Lake in southcentral Alaska consist of the relatively rare form of weakly armoured individuals with few lateral plates and no pelvic spines. Prator Lake has been sampled for threespine stickleback since 1983. Exotic northern pike (Esox lucius) were first observed in this lake in 1996. The appearance of pike corresponds with a dramatic decrease in stickleback numbers and apparent local extinction. The stickleback population may have been vulnerable to an exotic predator because Prator Lake lacks native piscivorous fishes, and this population had extreme armour reduction.
La métamorphose d'un cercle dans A la recherche du temps perdu
Authors: Ramsden Maureen A.
Published: September 2006

A la recherche du temps perdu contient de nombreux leitmotiv dont le cercle apparaît dans plusieurs contextes. Par exemple, toute heure qu'on a vécue, tout être qu'on a connu sont disposés à différents points du cercle que le temps forme autour de nous. C'est par l'intermédiaire de la mémoire involontaire que toute expérience est susceptible d’être rappelée dans sa plénitude. Le mot « cercle » lui‐même renforce le leitmotiv. Il y a le cercle social des Verdurin décrit comme « le dernier cercle de Dante » (Proust 1987–1989, I, 283)1. Combray lui‐même est aussi décrit en termes d'un cercle (I, 47). Des termes analogues apparaissent aussi. Le héros voit les deux côtés de Guermantes et de Méséglise comme deux vases tellement séparés qu'on ne peut pas les visiter le même après‐midi. Les allusions aux cercles et à des termes semblables sont nombreuses au niveau génétique, surtout au début du roman, où le héros est dans un état de demi‐sommeil. Par exemple, dans le cahier 3, 2e partie (I, 635) on lit « ma chambre fait un quart de cercle ». Le leitmotiv se retrouve surtout au niveau structurel. Le héros traverse une série de cercles dans sa vie dont le premier est le monde idéal de Combray, d'où il passe par le cercle de l'amour et du beau monde qui sont de plus en plus décevants. Ce sera seulement dans le cercle de l'art, et par l'aide de la mémoire involontaire, qu'il découvrira son salut. La dernière découverte, après que le héros est repassé par les autres cercles, sera le cercle intérieur qui lui fournira une nouvelle perspective sur le monde.
Nucleocytoplasmic Shuttling and the Biological Activity of Mouse Survivin are Regulated by an Active Nuclear Export Signal
Authors: Stauber Roland H. , Rabenhorst Uta , Rekik Alexander , Engels Knut , Bier Carolin , Knauer Shirley K.
Published: September 2006

Survivin appears to function as a regulator of cell division and as an apoptosis inhibitor in many species. Here, we characterized the nucleocytoplasmic transport of mouse survivin140, and its splice variants survivin121 and survivin40. We show that the dynamic intracellular localization of survivin140 is mediated by a Crm1‐dependent nuclear export signal (NES) present also in survivin121, but absent in survivin40. In contrast, neither survivin nor survivin splice variants contain an active nuclear import signal and seem to enter the nucleus by passive diffusion. The activity of the NES is required for survivin‐mediated protection against cell death inducing stimuli and influences protein degradation. During mitosis, NES‐deficient survivin variants fail to correctly localize to the mitotic machinery and promote proper cell division. In vivo and in vitro protein interaction assays show that survivin140 and survivin121 as well as their export‐deficient mutants are able to form homo‐ as well as heterodimers. The trans‐dominant negative phenotype observed upon expression of export‐deficient survivin appears, therefore, to be mediated by the formation of inactive survivin heterodimers. The survivin–Crm1 axis is essential for the biological activities of murine survivin, and mouse models will allow investigating its functional implications during development and tumorigenesis.
EGF‐Induced Activation of the EGF Receptor Does Not Trigger Mobilization of Caveolae
Authors: Kazazic Maja , Roepstorff Kirstine , Johannessen Lene E. , Pedersen Nina M. , van Deurs Bo , Stang Espen , Madshus Inger H.
Published: September 2006

Caveolae‐dependent endocytosis has recently been proposed in the uptake of EGF receptor (EGFR) at high concentrations of ligand. Consistently, upon incubation of HEp2 and HeLa cells with methyl‐β‐cyclodextrin, we observed a small inhibitory effect on endocytosis of ligated EGFR in HEp2 cells. However, immunoelectron microscopy showed the same relative amount of bound EGF localizing to caveolae on incubation with high and low concentrations of EGF, not supporting rapid recruitment of EGFR to caveolae. Live‐cell microscopy furthermore demonstrated that incubating HEp2 cells with high concentrations of EGF did not increase the mobility of caveolae. By RNA‐interference‐mediated knockdown of clathrin heavy chain in HEp2 and HeLa cells, we found that endocytosis of EGFR was efficiently inhibited both at high and low concentrations of EGF. Our results show that caveolae are not involved in endocytosis of EGF‐bound EGFR to any significant degree and that high concentrations of EGF do not further mobilize caveolae.
Rac upregulates tissue inhibitor of metalloproteinase‐1 expression by redox‐dependent activation of extracellular signal‐regulated kinase signaling
Authors: Engers Rainer , Springer Erik , Kehren Verena , Simic Tatjana , Young David A. , Beier Juliane , Klotz Lars‐O. , Clark Ian M. , Sies Helmut , Gabbert Helmut E.
Published: September 2006

The Rho‐like GTPase Rac regulates distinct actin cytoskeleton changes required for adhesion, migration and invasion of cells. Tiam1 specifically activates Rac, and Rac has been shown to affect several signaling pathways in a partly cell‐type‐specific manner. Recently, we demonstrated that Rac activation inhibits Matrigel invasion of human carcinoma cells by transcriptional upregulation of tissue inhibitor of metalloproteinase‐1. The purpose of the present study was to identify key mediators of Tiam1/Rac‐induced tissue inhibitor of metalloproteinase‐1 expression. Mutational analysis of the human tissue inhibitor of metalloproteinase‐1 promoter revealed a major role for a distinct activating protein‐1 site at −92/−86 and a minor role for an adjacent polyoma enhancer A3 site. Moreover, Rac activation induced the generation of reactive oxygen species and subsequent reactive oxygen species‐dependent activation of extracellular signal‐regulated kinase 1,2. In contrast, c‐Jun N‐terminal kinase and p38 mitogen‐activated protein kinase activities were not affected. In line with this, Tiam1/Rac‐induced tissue inhibitor of metalloproteinase‐1 expression as well as Tiam1/Rac‐induced binding of nuclear extracts to the activating protein‐1 site at −92/−86 were inhibited by catalase and by specific inhibitors of the extracellular signal‐related kinase‐1,2 activators, mitogen‐activated protein kinase kinase‐1 and mitogen‐activated protein kinase kinase‐2 (PD098059, U0126). In conclusion, Rac‐induced transcriptional upregulation of tissue inhibitor of metalloproteinase‐1 is mediated by reactive oxygen species‐dependent activation of extracellular signal‐related kinase‐1,2 and by transcription factors of the activating protein‐1 family.
Application of a fluorescent cobalamin analogue for analysis of the binding kinetics
Authors: Fedosov Sergey N. , Grissom Charles B. , Fedosova Natalya U. , Moestrup Søren K. , Nexø Ebba , Petersen Torben E.
Published: September 2006

Fluorescent probe rhodamine was appended to 5′ OH‐ribose of cobalamin (Cbl). The prepared conjugate, CBC, bound to the transporting proteins, intrinsic factor (IF) and transcobalamin (TC), responsible for the uptake of Cbl in an organism. Pronounced increase in fluorescence upon CBC attachment facilitated detailed kinetic analysis of Cbl binding. We found that TC had the same affinity for CBC and Cbl (Kd = 5 × 10−15 m), whereas interaction of CBC with the highly specific protein IF was more complex. For instance, CBC behaved normally in the partial reactions CBC + IF30 and CBC + IF20 when binding to the isolated IF fragments (domains). The ligand could also assemble them into a stable complex IF30–CBC–IF20 with higher fluorescent signal. However, dissociation of IF30–CBC–IF20 and IF–CBC was accelerated by factors of 3 and 20, respectively, when compared to the corresponding Cbl complexes. We suggest that the correct domain–domain interactions are the most important factor during recognition and fixation of the ligands by IF. Dissociation of IF–CBC was biphasic, and existence of multiple protein–analogue complexes with normal and partially corrupted structure may explain this behaviour. The most stable component had Kd = 1.5 × 10−13 m, which guarantees the binding of CBC to IF under physiological conditions. The specific intestinal receptor cubilin bound both IF–CBC and IF–Cbl with equal affinity. In conclusion, the fluorescent analogue CBC can be used as a reporting agent in the kinetic studies, moreover, it seems to be applicable for imaging purposes in vivo.
Multiple bacterial species reside in chronic wounds: a longitudinal study
Authors: Gjødsbøl Kristine , Christensen Jens Jørgen , Karlsmark Tonny , Jørgensen Bo , Klein Bjarke M , Krogfelt Karen A
Published: September 2006

The aim of the study was to investigate the bacterial profile of chronic venous leg ulcers and the importance of the profile to ulcer development. Patients with persisting venous leg ulcers were included and followed for 8 weeks. Every second week, ulcer samples were collected and the bacterial species present were identified. More than one bacterial species were detected in all the ulcers. The most common bacteria found were Staphylococcus aureus (found in 93·5% of the ulcers), Enterococcus faecalis (71·7%), Pseudomonas aeruginosa (52·2%), coagulase‐negative staphylococci (45·7%), Proteus species (41·3%) and anaerobic bacteria (39·1%). Resident bacterial species were present in all the ulcers. In 76% of the ulcers, two or more (up to five) resident bacterial species were found. The most common resident bacterial species were S. aureus and P. aeruginosa. Furthermore, ulcers with P. aeruginosa were found to be significantly larger than ulcers without the presence of P. aeruginosa (P < 0·005). Our study demonstrated that the chronic wound is colonised by multiple bacterial species and that once they are established many of them persist in the wound. Our results suggest that the presence of P. aeruginosa in venous leg ulcers can induce ulcer enlargement and/or cause delayed healing.
Epidermal growth factor intralesional infiltrations can prevent amputation in patients with advanced diabetic foot wounds
Authors: Acosta Jorge Berlanga , Savigne William , Valdez Calixto , Franco Neobalis , Alba Jose S , Rio Amaurys del , López‐Saura Pedro , Guillén Gerardo , Lopez Ernesto , Herrera Luís , Férnandez‐Montequín José
Published: September 2006

This study examined if a series of epidermal growth factor (EGF) local infiltrations can enhance the healing process of complicated diabetic wounds. Twenty‐nine in‐hospital patients with diabetic neuropathic or ischaemic lesions with high risk of amputation were treated in a non controlled pilot study conducted at the National Institute of Angiology, Havana. Lesions, classified as Wagner’s grade 3 or 4, included ulcers ≥20 cm2 for ≥25 days or amputation residual bases ≥30 cm2 for ≥15 days, healing refractory despite comprehensive wound care. EGF (25 μg) intralesional infiltrations (≈250 μl of a 25 μg/ml solution/injection point) were performed thrice weekly up to the eighth week. Wound closure was monitored during the treatment and recurrence examined for a year following discharge from hospital. Eighty‐six per cent of the patients treated showed a productive granulation at infiltration session 8. Histological examination at this point indicated a substantial wound matrix transformation, granulation tissue cell repopulation and angiogenesis. Of the 29 patients treated, amputation was prevented in 17 (58·6%) of them who completed 24 infiltration sessions. They averaged 71·1 ± 18·3% of reepithelisation during a mean in‐hospital period of 66·5 ± 4·9 days. Wound recurrence after 1 year of follow‐up appeared in only one patient. Preliminary evidences suggest that EGF intralesional infiltrations may be effective in reducing diabetic lower limb amputation.
Altered skin blood perfusion in areas with non blanchable erythema: an explorative study
Authors: Lindgren Margareta , Malmqvist Lars‐Åke , Sjöberg Folke , Ek Anna‐Christina
Published: September 2006

Non blanchable erythema, i.e. stage I pressure ulcer, is common in patients in acute and geriatric care and in nursing homes. Research has shown that this type of lesions is prone to develop into more severe pressure ulcers. The peripheral skin blood perfusion is of major importance for the development of pressure ulcers. The aim of this study was to explore the peripheral skin blood perfusion over time, in areas with non blanchable erythema and in corresponding undamaged areas on the opposite side of the body. A total of 19 measurements were performed, over time, using a laser Doppler perfusion imager. The blood flow distribution profiles over areas with non blanchable erythema and undamaged skin were found to be different. As the area of the non blanchable erythema decreased, the blood perfusion distribution profiles gradually became more heterogeneous; an area of high blood perfusion in the centre of the lesions was seen and the perfusion successively decreased closer to the edge. These results indicate that there are differences in blood perfusion between skin areas of non blanchable erythema and undamaged skin. The results also indicate that the visible redness in areas with non blanchable erythema is related to altered blood perfusion. The skin blood perfusion also seems to increase in relation to the size of the non blanchable erythema.
Comparing Vardenafil and Sildenafil in the Treatment of Men with Erectile Dysfunction and Risk Factors for Cardiovascular Disease: A Randomized, Double-Blind, Pooled Crossover Study
Authors: Rubio-Aurioles Eusebio , Porst Hartmut , Eardley Ian , Goldstein Irwin
Published: September 2006

Introduction

Data from head-to-head clinical trials of phosphodiesterase type 5 (PDE5) inhibitors are scarce, making it difficult for clinicians to differentiate among these agents to select the most appropriate treatment for their patients with erectile dysfunction (ED).

Aim

This randomized, double-blind, crossover head-to-head clinical trial compared patient preference, efficacy, and safety of vardenafil and sildenafil in men with ED and diabetes, hypertension, and/or hyperlipidemia.

Methods

Prospective analysis was performed on two studies in which 1,057 men were randomized to vardenafil 20 mg (N = 530) or sildenafil 100 mg (2 × 50 mg encapsulated tablets) (N = 527) for 4 weeks. Following a 1-week washout, patients switched treatment for 4 weeks.

Main Outcome Measures

Patients were asked about overall preference: “Overall, which medication do you prefer?”, plus 11 other preference questions relating to their ED treatment. Efficacy assessments after each treatment period included the erectile function (EF) domain score of the International Index of Erectile Function (IIEF); Sexual Encounter Profile (SEP) diary questions SEP2 and SEP3; Global Assessment Question (GAQ); and Treatment Satisfaction Scale (TSS). Data regarding adverse events were collected throughout the study.

Results

A total of 931 men (mean age 57.9 years) were included in the intent-to-treat (ITT) population. Non-inferiority of vardenafil over sildenafil was achieved for overall preference (vardenafil 38.9%; sildenafil 34.5%; and no preference 26.6%). Additionally, the change from baseline in the EF domain score of the IIEF achieved nominal significance for vardenafil over sildenafil (10.00 vs. 9.40; P = 0.0052). Patients also had a higher percentage of positive responses for vardenafil for SEP2, SEP3, GAQ, and 12 of 19 questions on the TSS. Both drugs were well tolerated.

Conclusions

This randomized, double-blind, head-to-head trial in ED patients with cardiovascular risk factors demonstrated noninferiority of vardenafil for overall preference. Vardenafil achieved nominal statistical superiority over sildenafil for several frequently used efficacy measures. Both drugs were well tolerated.
Temporal Dynamics of Rich Moth Ensembles in the Montane Forest Zone in Southern Ecuador1
Authors: Hilt Nadine , Brehm Gunnar , Fiedler Konrad
Published: September 2006

We studied temporal dynamics of diverse moth ensembles (Arctiidae and Geometridae) in early and late succession stages of forest recovery in the montane zone of southern Ecuador. Moths were sampled using weak light sources (2 × 15 W tubes per trap) during three sampling periods (March–April 2002, wet season; October–November 2002, and August–October 2003, both “dry” seasons). Arctiid moth abundance hardly varied between sampling periods. Estimates of local diversity were lower in 2002 (wet and dry season) than in the dry season 2003, and ensemble composition was more strongly affected by sampling period rather than habitat differences. Geometridae ensembles revealed stronger temporal patterns. Geometrid abundance increased about twofold from the wet to the dry season, and temporal effects on species composition were far more pronounced that in arctiids. These differences might hint to variation in the dependence of geometrid versus arctiid larvae on ephemeral plant resources. Despite these significant temporal dynamics, in both families only a few of the more common species analyzed individually showed strong temporal changes in abundance. Almost all common species occurred as adults during all sampling periods. Therefore, even though temporal dynamics of moth ensembles are not negligible, both moth families are suitable “indicators” of community diversity and change along the succession gradient. Samples must be large enough, however, and preferably should be collated over various times of the year and in parallel, to allow for valid statements about moth diversity and species compositions in relation to habitat differences. These recommendations undermine the validity of the concept of “rapid biodiversity inventories” for speciose tropical insect communities.
Seasonality of Reproduction in Amazon River Dolphins (Inia geoffrensis) in Three Major River Basins of South America1
Authors: McGuire T. L. , Aliaga‐Rossel E. R.
Published: September 2006

Reproduction of Amazon River Dolphins, Inia geoffrensis, is generally reported to be highly seasonal; however, this conclusion is based on studies from only one area of Inia distribution from throughout the Amazon and Orinoco river basins. Our observations of live dolphins from the Orinoco, Amazon, and Mamoré river basins (in Venezuela, Peru and Bolivia, respectively) indicate that reproduction in Inia often occurs year‐round, with seasonal peaks varying according to geographic location. Inia neonates in Peru and Bolivia were seen in all seasons, and were observed most often in falling water (season was defined by relative water level). Conversely, neonates in Venezuela were seen at the end of low water and in rising water, yet were never observed during falling water. Inia mating behavior in Peru was observed in all seasons, while mating was observed only during falling and low water in Bolivia. Our review of the literature from throughout the range of Inia indicates variation in reproductive seasonality, with year‐round reproduction in some areas. Seasonality of peaks in births varied according to study area, and may be more closely associated with local environmental and prey conditions than with taxonomic relatedness, relative seasonal differences in water levels, or broad geographic distribution.
AN EXPLORATION INTO PARTICIPATION IN A FAITH‐BASED PRISON PROGRAM*
Authors: CAMP SCOTT D. , KLEIN‐SAFFRAN JODY , KWON OKYUN (KARL) , DAGGETT DAWN M. , JOSEPH VICTORIA
Published: September 2006

Research Summary:

The current research investigates the faith, sociodemographic, psychological, and criminal history factors associated with the decision to volunteer for a faith‐based program. Operational records were combined with data collected from self‐administered surveys. The results of the logistic regression model were successful in identifying factors related to program participation, including factors not included in previous studies. The findings suggest that program participants are motivated to make changes in their lives and are seeking their way in a religious sense. For example, program participants scored higher on average on the motivation for change scale used here, had higher rates of attendance in religious services since incarceration, and were more active in reading sacred scripture. Conversely, inmates who claimed higher levels of knowledge about their faith were less likely to participate in the Life Connections Program examined here.

Policy Implications:

The results of the analysis suggest that certain religious characteristics are associated with participation in a faith‐based program. The implication is that religious program providers need to pay attention to the match between the program content and the charactertistics of their potential program participants. The results also demonstrate the need to capture differences between participants and comparison subjects on dimensions not usually included in evaluations of faith‐based programs. Without knowledge of the selection process, there is no way to determine whether observed differences between program participants and “comparisons” are due to actual program effects or are an artifact of preexisting differences between the groups.
Immigration, Multiculturalism, and the Welfare State
Authors: Kymlicka Will , Banting Keith
Published: September 2006

Popular opposition to immigration is rooted in many factors. In this essay, we focus on one specific issue that has become prominent in recent debates—namely, the fear that the welfare state is being undermined by the impact of increasing ethnic and racial diversity. There are actually two concerns here: first, that ethnic and racial diversity as such makes it more difficult to sustain redistributive social policies because it is difficult to generate feelings of national solidarity and trust across ethnic and racial lines, and second, that the “multiculturalism” policies adopted to recognize or accommodate immigrant groups tend to further undermine national solidarity and trust. If either of these hypotheses were true, the very idea of a “multicultural welfare state,” a welfare state that respects and accommodates diversity, would be almost a contradiction in terms. We review the existing evidence and suggest that both hypotheses are overstated. The evidence to date suggests that there is no inherent tendency for either immigrant ethnic diversity or multiculturalism policies to erode the welfare state. We conclude with some speculation about the implications of this evidence for debates about the rights of noncitizens.
Lyapunov Based Performance Guarantees for the Potential Field Lane-keeping Assistance System
Authors: Rossetter Eric J. , Gerdes J. Christian
Published: September 2006

Active lane-keeping assistance systems hold the potential to save thousands of lives every year, but require an approach that can simultaneously work cooperatively with the driver and provide a guaranteed level of safety. One approach that meets these dual demands is to passively couple the vehicle to the environment using the paradigm of “artificial” potential fields. This paper develops such a controller and demonstrates that with appropriate choice of a preview or look-ahead distance, the lateral and yaw dynamics effectively decouple, enabling a tight energy-based bound on lateral error. Since this control scheme does not attempt to track a desired trajectory, disturbances encountered during normal driving (such as road curvature) will alter the path of the vehicle. However, the energy theoretic framework can be used to develop a Lyapunov-based bound that handles general time-varying disturbances. This technique provides bounds on the lateral motion of the vehicle that are sufficiently tight to use as a design tool. Experimental results verify that this bound, and the system structure itself, work well in practice, providing guaranteed assistance in a cooperative manner.
Onset of Vortex Shedding in a Periodic Array of Circular Cylinders
Authors: Zhang L. , Balachandar S.
Published: September 2006

Hopf bifurcation of steady base flow and onset of vortex shedding over a transverse periodic array of circular cylinders is considered. The influence of transverse spacing on critical Reynolds number is investigated by systematically varying the gap between the cylinders from a small value to large separations. The critical Reynolds number behavior for the periodic array of circular cylinders is compared with the corresponding result for a periodic array of long rectangular cylinders considered in [Balanchandar, S., and Parker, S. J., 2002, “Onset of Vortex Shedding in an Inline and Staggered Array of Rectangular Cylinders,” Phys. Fluids, 14, pp. 3714–3732]. The differences between the two cases are interpreted in terms of differences between their wake profiles.
Nonlinear Manipulation Control of a Compliant Object by Dual Fingers
Authors: Doulgeri Z. , Golfakis A.
Published: September 2006

This paper refers to the control of the position and contact forces of a compliant rectangular object grasped by a pair of robot fingers for the planar case, using input-output feedback linearization techniques. Point contact with friction is assumed and the linearizing control is designed for the case of controlling the object position and grasping force and then extended to include the constraint forces and the object orientation. In the last case, an appropriate output transformation is proposed to avoid the singularity of the decoupling matrix and apply the method successfully. This work considers the planar case and provides simulation results that confirm the theoretical findings.
Hybrid Genetic Algorithm: A Robust Parameter Estimation Technique and its Application to Heavy Duty Vehicles
Authors: Xiao Jie , Kulakowski Bohdan
Published: September 2006

In this paper, hybrid parameter estimation technique is developed to improve computational efficiency and accuracy of pure GA-based estimation. The proposed strategy integrates a GA and the Maximum Likelihood Estimation. Choices of input signals and estimation criterion are discussed involving an extensive sensitivity analysis. Experiment-related aspects, such as the imperfection of data acquisition, are also considered. Computer simulation results reveal that the hybrid parameter estimation method proposed in this study is very efficient and clearly outperforms conventional techniques and pure GAs in accuracy, efficiency, as well as robustness with respect to the initial guesses and measurement uncertainty. Primary experimental validation is also implemented, including the interpretation of field test data, as well as analysis of errors associated with aspects of experiment design.
Dynamics of a Quasiperiodically Forced Rayleigh Oscillator
Authors: Chedjou J. C. , Kana L. K. , Moussa I. , Kyamakya K. , Laurent A.
Published: September 2006

This paper studies the dynamics of a self-excited oscillator with two external periodic forces. Both the nonresonant and resonant states of the oscillator are considered. The hysteresis boundaries are derived in terms of the system’s parameters. The stability conditions of periodic oscillations are derived. Routes to chaos are investigated both from direct numerical simulation and from analog simulation of the model describing the forced oscillator. One of the most important contributions of this work is to provide a set of reliable analytical expressions (formulas) describing the system’s behavior. These are of great importance to design engineers. The reliability of the analytical formulas is demonstrated by a very good agreement with the results obtained by both the numeric and experimental analyses.
Robust H∞ Output Feedback Control Design for Takagi-Sugeno Systems with Markovian Jumps: A Linear Matrix Inequality Approach
Authors: Nguang Sing Kiong , Shi Peng
Published: September 2006

This paper investigates the H∞ output feedback control design for a class of uncertain nonlinear systems with Markovian jumps which can be described by Takagi-Sugeno models. Based on a linear matrix inequality (LMI), LMI-based sufficient conditions for the existence of a robust output feedback controller, such that the L2-gain from an exogenous input to a regulated output is less than or equal to a prescribed value, are derived. An illustrative example is used to demonstrate the effectiveness of the proposed design techniques.
Experimental Characterization and Gray-Box Modeling of Spool-Type Automotive Variable-Force-Solenoid Valves With Circular Flow Ports and Notches
Authors: Cao M. , Wang K. W. , DeVries L. , Fujii Y. , Tobler W. E. , Pietron G. M.
Published: September 2006

In automatic transmission design, electronic control techniques have been adopted through proportional variable-force-solenoid valves, which typically consist of spool-type valves (Christenson, W. A., 2000, SAE Technical Paper Series, 2000-01-0116). This paper presents an experimental investigation and neural network modeling of the fluid force and flow rate for a spool-type hydraulic valve with symmetrically distributed circular ports. Through extensive data analysis, general trends of fluid force and flow rate are derived as functions of pressure drop and valve opening. To further reveal the insights of the spool valve fluid field, equivalent jet angle and discharge coefficient are calculated from the measurements, based on the lumped parameter models. By incorporating physical knowledge with nondimensional artificial neural networks (NDANN), gray-box NDANN-based hydraulic valve system models are also developed through the use of equivalent jet angle and discharge coefficient. The gray-box NDANN models calculate fluid force and flow rate as well as the intermediate variables with useful design implications. The network training and testing demonstrate that the gray-box NDANN fluid field estimators can accurately capture the relationship between the key geometry parameters and discharge coefficient/jet angle. The gray-box NDANN maintains the nondimensional network configuration, and thus possesses good scalability with respect to the geometry parameters and key operating conditions. All of these features make the gray-box NDANN fluid field estimator a valuable tool for hydraulic system design.
Networked Real-Time Control Strategy Dealing With Stochastic Time Delays and Packet Losses
Authors: Kim Won-jong , Ji Kun , Ambike Ajit
Published: September 2006

A novel model-predictive-control strategy with a timeout scheme and p-step-ahead state estimation is presented in this paper to overcome the adverse influences of stochastic time delays and packet losses encountered in network-based distributed real-time control. An open-loop unstable magnetic-levitation (maglev) test bed was constructed and employed for its experimental verification. The compensation algorithms developed in this paper deal with the network-induced stochastic time delays and packet losses in both the forward path and the feedback path simultaneously. With the p-sampling-period delay upper bound, the networked control system (NCS) can also accommodate up to p−1 successive packet losses. Experimental results demonstrate the feasibility and effectiveness of this networked real-time control strategy.
An Upper Bound on the Maximum Stability Radius Achievable by State Feedback
Authors: Rajamani R. , Cho Y. M.
Published: September 2006

In this paper we relate the stability radius that can be achieved for the closed-loop matrix (A−BK) to the distance to unstabilizability of the pair (A,B). In the paper we show that the closed-loop matrix (A−BK) can achieve a stability radius of γ with a real feedback matrix K only if the distance to unstabilizability of (A,B) is greater than γ. Thus the distance to the unstabilizability of (A,B) provides an upper bound on the maximum stability radius that can be achieved by state feedback.
Surfactant Effects on the Free Surface Thermal Structure and Subsurface Flow in a Wind-Wave Tunnel
Authors: Phongikaroon Supathorn , Judd K. Peter
Published: September 2006

In this study, the dynamic effects of surfactant (oleyl alcohol) on the surface temperature and the near surface velocity field of a wind driven free surface are investigated. Different surfactant concentrations and wind speeds were examined to elucidate the flow physics. The water surface was imaged with an infrared (IR) detector and the subsurface flow was interrogated utilizing digital particle image velocimetry (DPIV). The IR imagery reveals the presence of a Reynolds ridge that demarcates the boundary between clean (hot) fluid and contaminated (cold) fluid. The clean region was found to be composed of laminae structures known as fishscales. A “wake region” which is an intermediate temperature region resulting from mixing of the near surface fluid layers develops behind the ridge. Experimental results from infrared imagery indicate that the fishscales in the clean region become elongated and narrowed as the wind speed increases. In addition, the results reveal that higher wind speed is required to form a Reynolds ridge in the presence of higher surfactant concentration. The plots of the surface temperature probability density functions reveal that these thermal structures undergo the same evaporative process while the increase in wind speed enhances this process. DPIV results reveal that the growth of a subsurface boundary layer for the contaminated case is more pronounced than that for the clean case.
Transpiration Induced Shock Boundary-Layer Interactions
Authors: Wasistho B.
Published: September 2006

Steady and unsteady shock boundary-layer interactions are studied numerically by solving the two-dimensional time-dependent Navier-Stokes equations. To validate the numerical method, the steady interaction is compared with measurements and other numerical results reported in the literature. The numerical study of the steady interaction leads to a suitable method for transpiration boundary conditions. The method applies to unsteady flows as well. Using the validated numerical method, we show that an unsteady shock boundary-layer interaction can occur in a supersonic flow over a flat plate subjected to suction and blowing from the opposite side of the plate, even though the imposed transpiration is steady. Depending on the Mach number, the Reynolds number, the distance of the transpiration boundary to the lower wall, and the transpiration profile, the unsteadiness can be inviscid or viscous dominated. The viscous effect is characterized by the occurrence of self-excited vortex shedding. A criterion for the onset of vortex shedding for internal compressible flows is also proposed.
Design of a Low-Turbulence, Low-Pressure Wind-Tunnel for Micro-Aerodynamics
Authors: Martin Michael J. , Scavazze Kevin J. , Boyd Iain D. , Bernal Luis P.
Published: September 2006

A novel wind-tunnel facility has been designed for measurement of lift and drag on micromachined airfoils. The tunnel is designed to operate with pressures ranging from 0.15 to 1.0 atmosphere, over a velocity range of 30 to 100m∕s, allowing for independent control of Reynolds and Knudsen number. The tunnel is designed for testing of airfoils with chords of 10 to 100 microns, giving a range of Reynolds numbers from 10 to 600, with Knudsen numbers reaching 0.01. Due to the structural constraints of the airfoils being tested, the wind tunnel has a 1cm cross-section. This small size allows the use of a 100-1 contraction area, and extremely fine turbulence screens, creating a low turbulence facility. Computational fluid dynamics is used to show that an ultra-short 100-1 contraction provides uniform flow without separation, or corner vortices. Velocity data obtained with impact and hot-wire probes indicate uniform flow and turbulence intensities below 0.5%.
Canine Distemper Virus Uses both the Anterograde and the Hematogenous Pathway for Neuroinvasion
Authors: Rudd Penny A. , Cattaneo Roberto , von Messling Veronika
Published: September 2006

Canine distemper virus (CDV), a member of the
Morbillivirus
genus that also includes measles virus, frequently causes neurologic complications, but the routes and timing of CDV invasion of the central nervous system (CNS) are poorly understood. To characterize these events, we cloned and sequenced the genome of a neurovirulent CDV (strain A75/17) and produced an infectious cDNA that expresses the green fluorescent protein. This virus fully retained its virulence in ferrets: the course and signs of disease were equivalent to those of the parental isolate. We observed CNS invasion through two distinct pathways: anterogradely via the olfactory nerve and hematogenously through the choroid plexus and cerebral blood vessels. CNS invasion only occurred after massive infection of the lymphatic system and spread to the epithelial cells throughout the body. While at early time points, mostly immune and endothelial cells were infected, the virus later spread to glial cells and neurons. Together, the results suggest similarities in the timing, target cells, and CNS invasion routes of CDV, members of the
Morbillivirus
genus, and even other neurovirulent paramyxoviruses like Nipah and mumps viruses.
von Hippel-Lindau Disease
Authors: Kaelin William G.
Published: September 2006

von Hippel-Lindau disease, which is characterized by an increased risk of hemangioblastomas, clear cell renal carcinomas, and pheochromocytomas, is caused by inactivating mutations of the VHL tumor suppressor gene. The VHL gene product, pVHL, has multiple functions, but the best documented, and the one most clearly linked to tumor development, relates to its role as the substrate recognition module of a ubiquitin ligase complex that targets hypoxia-inducible factor (HIF) for destruction. pVHL function is often compromised in sporadic kidney cancers, and inhibitors of the HIF-responsive growth factor (vascular endothelial growth factor) are active against this disease. pVHL, by inhibiting atypical protein kinase C and hence JunB, also affects neuronal survival, as do the products of the other genes linked to familial pheochromocytoma or paraganglioma (NF1, RET, SDHB, SDHC, and SDHD). It is hypothesized that tumor-associated alleles of these genes allow primitive sympathoadrenal precursors to escape developmental culling, and that such cells are at increased risk of forming tumors.
Identification of depot-specific human fat cell progenitors through distinct expression profiles and developmental gene patterns
Authors: Tchkonia Tamara , Lenburg Marc , Thomou Thomas , Giorgadze Nino , Frampton Garrett , Pirtskhalava Tamar , Cartwright Andrew , Cartwright Mark , Flanagan John , Karagiannides Iordanes , Gerry Norman , Forse R. Armour , Tchoukalova Yourka , Jensen Michael D. , Pothoulakis Charalabos , Kirkland James L.
Published: September 2006

Anatomically separate fat depots differ in size, function, and contribution to pathological states, such as the metabolic syndrome. We isolated preadipocytes from different human fat depots to determine whether the basis for this variation is partly attributable to differences in inherent properties of fat cell progenitors. We found that genome-wide expression profiles of primary preadipocytes cultured in parallel from abdominal subcutaneous, mesenteric, and omental fat depots were distinct. Interestingly, visceral fat was not homogeneous. Preadipocytes from one of the two main visceral depots, mesenteric fat, had an expression profile closer to that of subcutaneous than omental preadipocytes, the other main visceral depot. Expression of genes that regulate early development, including homeotic genes, differed extensively among undifferentiated preadipocytes isolated from different fat depots. These profiles were confirmed by real-time PCR analysis of preadipocytes from additional lean and obese male and female subjects. We made preadipocyte strains from single abdominal subcutaneous and omental preadipocytes by expressing telomerase. Depot-specific developmental gene expression profiles persisted for 40 population doublings in these strains. Thus, human fat cell progenitors from different regions are effectively distinct, consistent with different fat depots being separate mini-organs.
Fetuin-A uptake in bovine vascular smooth muscle cells is calcium dependent and mediated by annexins
Authors: Chen Neal X. , O'Neill Kalisha D. , Chen Xianming , Duan Danxia , Wang Exing , Sturek Michael S. , Edwards Jason M. , Moe Sharon M.
Published: September 2006

Fetuin-A is a known inhibitor of vascular calcification in vitro. In arteries with calcification, there is increased immunostaining for fetuin-A. However, vascular smooth muscle cells (VSMC) do not synthesize fetuin-A, suggesting fetuin-A may be endocytosed to exert its inhibitory effects. To examine the mechanism by which fetuin-A is taken up in bovine VSMC (BVSMC), we examined living cells by confocal microscopy and determined the uptake of Cy5-labeled fetuin-A. The results demonstrated that fetuin-A was taken up in BVSMC only in the presence of extracellular calcium, whereas phosphorus had no effect. Additional studies demonstrated the calcium-dependent uptake was specific for fetuin-A and only observed in BVSMC and osteoblasts, but not epithelial, endothelial, or adipose cells. The uptake was dose dependent, but could not be inhibited by excess unlabeled fetuin-A, suggesting a fluid phase rather than a receptor-mediated process. Fetuin-A also induced a sustained increase in intracellular calcium in BVSMC in the presence of extracellular calcium, whereas there was no increase in the absence of extracellular calcium. To further characterize the uptake, we utilized an inhibitor of annexin calcium channel activity, demonstrating inhibition of both fetuin-A uptake and intracellular calcium increase. Finally, we demonstrate that fetuin-A binds to annexin II at the cell membrane of BVSMC. In summary, our study demonstrates calcium- and annexin-dependent uptake of fetuin-A that leads to a sustained rise in intracellular calcium. This regulated uptake may be a mechanism by which fetuin-A inhibits VSMC calcification in the presence of excess calcium.
Novel method for high-throughput phenotyping of sleep in mice
Authors: Pack Allan I. , Galante Raymond J. , Maislin Greg , Cater Jacqueline , Metaxas Dimitris , Lu Shan , Zhang Lin , Smith Randy Von , Kay Timothy , Lian Jie , Svenson Karen , Peters Luanne L.
Published: September 2006

Assessment of sleep in mice currently requires initial implantation of chronic electrodes for assessment of electroencephalogram (EEG) and electromyogram (EMG) followed by time to recover from surgery. Hence, it is not ideal for high-throughput screening. To address this deficiency, a method of assessment of sleep and wakefulness in mice has been developed based on assessment of activity/inactivity either by digital video analysis or by breaking infrared beams in the mouse cage. It is based on the algorithm that any episode of continuous inactivity of ≥40 s is predicted to be sleep. The method gives excellent agreement in C57BL/6J male mice with simultaneous assessment of sleep by EEG/EMG recording. The average agreement over 8,640 10-s epochs in 24 h is 92% ( n = 7 mice) with agreement in individual mice being 88–94%. Average EEG/EMG determined sleep per 2-h interval across the day was 59.4 min. The estimated mean difference (bias) per 2-h interval between inactivity-defined sleep and EEG/EMG-defined sleep was only 1.0 min (95% confidence interval for mean bias −0.06 to +2.6 min). The standard deviation of differences (precision) was 7.5 min per 2-h interval with 95% limits of agreement ranging from −13.7 to +15.7 min. Although bias significantly varied by time of day ( P = 0.0007), the magnitude of time-of-day differences was not large (average bias during lights on and lights off was +5.0 and −3.0 min per 2-h interval, respectively). This method has applications in chemical mutagenesis and for studies of molecular changes in brain with sleep/wakefulness.
On the global behavior of the nonlinear difference equation xn+1 = f(pn, xn−m, xn−t(k+1)+1)
Authors: Sun Taixiang , Xi Hongjian
Published: September 2006

We consider the following nonlinear difference equation:
xn+1 = f(pn, xn−m, xn−t(k+1)+1), n = 0, 1, 2, …, where m ∈ {0, 1, 2, …} and
k, t ∈ {1, 2, …} with 0 ≤ m < t(k + 1) − 1, the initial
values x−t(k+1)+1, x−t(k+1)+2, …, x0 ∈ (0, +∞),
and is a positive sequence of the period
k + 1. We give sufficient conditions under which every positive
solution of this equation tends to the period k + 1 solution.
Nonrigid Medical Image Registration by Finite‐Element Deformable Sheet‐Curve Models
Authors: Xuan Jianhua , Wang Yue , Freedman Matthew T. , Adali Tulay , Shields Peter
Published: September 2006

Image‐based change quantitation has been recognized as a promising
tool for accurate assessment of tumor′s early response to
chemoprevention in cancer research. For example, various changes
on breast density and vascularity in glandular tissue are the
indicators of early response to treatment. Accurate extraction of
glandular tissue from pre‐ and postcontrast magnetic resonance
(MR) images requires a nonrigid registration of sequential MR
images embedded with local deformations. This paper reports a
newly developed registration method that aligns MR breast images
using finite‐element deformable sheet‐curve models. Specifically,
deformable curves are constructed to match the boundaries
dynamically, while a deformable sheet of thin‐plate splines is
designed to model complex local deformations. The experimental
results on both digital phantoms and real MR breast images using
the new method have been compared to point‐based thin‐plate‐spline
(TPS) approach, and have demonstrated a significant and robust
improvement in both boundary alignment and local deformation
recovery.
Classical solutions of linear regulator for degenerate diffusions
Authors: Baten Md. Azizul
Published: September 2006

We study a stochastic control problem for linear degenerate systems.
We establish the existence of a classical solution of the degenerate Bellman
equation by the technique of viscosity solutions, and the optimal policy is shown
to exist from the optimality conditions.