bluuebunny/crossref_metadata_2025 huggingface dataset:
Gq-coupled Purinergic Receptors Inhibit Insulin-like Growth Factor-I/Phosphoinositide 3-Kinase Pathway-dependent Keratinocyte Migration
Authors: Taboubi Salma , Garrouste Françoise , Parat Fabrice , Pommier Gilbert , Faure Emilie , Monferran Sylvie , Kovacic Hervé , Lehmann Maxime
Published: January 2010

Insulin-like growth factor-I (IGF-I) activation of phosphoinositol 3-kinase (PI3K) is an essential pathway for keratinocyte migration that is required for epidermis wound healing. We have previously reported that activation of Gα(q/11)-coupled-P2Y2purinergic receptors by extracellular nucleotides delays keratinocyte wound closure. Here, we report that activation of P2Y2receptors by extracellular UTP inhibits the IGF-I–induced p110α-PI3K activation. Using siRNA and pharmacological inhibitors, we demonstrate that the UTP antagonistic effects on PI3K pathway are mediated by Gα(q/11)—and not G(i/o)—independently of phospholipase Cβ. Purinergic signaling does not affect the formation of the IGF-I receptor/insulin receptor substrate-I/p85 complex, but blocks the activity of a membrane-targeted active p110α mutant, indicating that UTP acts downstream of PI3K membrane recruitment. UTP was also found to efficiently attenuate, within few minutes, the IGF-I–induced PI3K-controlled translocation of the actin-nucleating protein cortactin to the plasma membrane. This supports the UTP ability to alter later migratory events. Indeed, UTP inhibits keratinocyte spreading and migration promoted by either IGF-I or a membrane-targeted active p110α mutant, in a Gα(q/11)-dependent manner both. These findings provide new insight into the signaling cross-talk between receptor tyrosine kinase and Gα(q/11)-coupled receptors, which mediate opposite effects on p110α-PI3K activity and keratinocyte migration.
The RhoA Activator GEF-H1/Lfc Is a Transforming Growth Factor-β Target Gene and Effector That Regulates α-Smooth Muscle Actin Expression and Cell Migration
Authors: Tsapara Anna , Luthert Phillip , Greenwood John , Hill Caroline S. , Matter Karl , Balda Maria S.
Published: January 2010

Maintenance of the epithelial phenotype is crucial for tissue homeostasis. In the retina, dedifferentiation and loss of integrity of the retinal pigment epithelium (RPE) leads to retinal dysfunction and fibrosis. Transforming growth factor (TGF)-β critically contributes to RPE dedifferentiation and induces various responses, including increased Rho signaling, up-regulation of α-smooth muscle actin (SMA), and cell migration and dedifferentiation. Cellular TGF-β responses are stimulated by different signal transduction pathways: some are Smad dependent and others Smad independent. Alterations in Rho signaling are crucial to both types of TGF-β signaling, but how TGF-β-stimulates Rho signaling is poorly understood. Here, we show that primary RPE cells up-regulated GEF-H1 in response to TGF-β. GEF-H1 was the only detectable Rho exchange factor increased by TGF-β1 in a genome-wide expression analysis. GEF-H1 induction was Smad4-dependant and led to Rho activation. GEF-H1 inhibition counteracted α-SMA up-regulation and cell migration. In patients with retinal detachments and fibrosis, migratory RPE cells exhibited increased GEF-H1 expression, indicating that induction occurs in diseased RPE in vivo. Our data indicate that GEF-H1 is a target and functional effector of TGF-β by orchestrating Rho signaling to regulate gene expression and cell migration, suggesting that it represents a new marker and possible therapeutic target for degenerative and fibrotic diseases.
Requirements and Reasons for Effective Inhibition of the Anaphase Promoting Complex Activator Cdh1
Authors: Robbins Jonathan A. , Cross Frederick R.
Published: January 2010

Anaphase promoting complex (APC)-Cdh1 targets multiple mitotic proteins for degradation upon exit from mitosis into G1; inhibitory phosphorylation of Cdh1 by cyclin-dependent kinase (CDK) and Polo kinase has been proposed to prevent the premature degradation of substrates in the ensuing cell cycle. Here, we demonstrate essentiality of CDK phosphorylation of Cdh1 in Saccharomyces cerevisiae by exact endogenous gene replacement of CDH1 with CDK-unphosphorylatable CDH1-m11; in contrast, neither Cdh1 polo kinase sites nor polo interaction motifs are required. CDH1-m11 cells arrest in the first cycle with replicated DNA and sustained polarized growth; most cells have monopolar spindles. Blocking proteolysis of the Cin8 kinesin in CDH1-m11 cells does not promote spindle pole body (SPB) separation. In contrast, expression of undegradable mitotic cyclin results in both SPB separation and the restoration of isotropic growth. A minority of CDH1-m11 cells arrest with short bipolar spindles that fail to progress to anaphase; this can be accounted for by a failure to accumulate Cdc20 and consequent failure to cleave cohesin. Bipolar spindle assembly in CDH1-m11 cells is strikingly sensitive to gene dosage of the stoichiometric Cdh1 inhibitor ACM1. Thus, different spindle-regulatory pathways have distinct sensitivities to Cdh1, and ACM1 may buffer essential CDK phosphorylation of Cdh1.
Emi2 Inhibition of the Anaphase-promoting Complex/Cyclosome Absolutely Requires Emi2 Binding via the C-Terminal RL Tail
Authors: Ohe Munemichi , Kawamura Yoshiko , Ueno Hiroyuki , Inoue Daigo , Kanemori Yoshinori , Senoo Chiharu , Isoda Michitaka , Nakajo Nobushige , Sagata Noriyuki
Published: January 2010

Emi2 (also called Erp1) inhibits the anaphase-promoting complex/cyclosome (APC/C) and thereby causes metaphase II arrest in unfertilized vertebrate eggs. Both the D-box and the zinc-binding region (ZBR) of Emi2 have been implicated in APC/C inhibition. However, it is not well known how Emi2 interacts with and hence inhibits the APC/C. Here we show that Emi2 binds the APC/C via the C-terminal tail, termed here the RL tail. When expressed in Xenopus oocytes and egg extracts, Emi2 lacking the RL tail fails to interact with and inhibit the APC/C. The RL tail itself can directly bind to the APC/C, and, when added to egg extracts, either an excess of RL tail peptides or anti-RL tail peptide antibody can dissociate endogenous Emi2 from the APC/C, thus allowing APC/C activation. Furthermore, and importantly, the RL tail–mediated binding apparently promotes the inhibitory interactions of the D-box and the ZBR (of Emi2) with the APC/C. Finally, Emi1, a somatic paralog of Emi2, also has a functionally similar RL tail. We propose that the RL tail of Emi1/Emi2 serves as a docking site for the APC/C, thereby promoting the interaction and inhibition of the APC/C by the D-box and the ZBR.
Morphogenesis in Kyoto: A Confluence of Cell and Developmental Biology
Authors: Zallen Jennifer A. , Yap Alpha S.
Published: January 2010

Understanding morphogenesis is the ultimate multidisciplinary (ad)venture. Three-dimensional tissues are generated from the actions of genes, biochemical pathways, and cells that form multicellular networks and interact with their biomechanical environment. A comprehensive explanation of morphogenetic processes must encompass these different levels of analysis. A recent meeting in Kyoto on “Building the Body Plan: How Cell Adhesion, Signaling, and Cytoskeletal Regulation Shape Morphogenesis” highlighted recent advances in tackling this challenging problem.
Allocating Conservation Resources Under The Endangered Species Act
Authors: Langpap Christian , Kerkvliet Joe
Published: January 2010

We explore the allocation of recovery funds to species listed under the Endangered Species Act. We simulate outcomes from allocations based on the U.S. Fish and Wildlife Service's priority rankings and on rankings used in U.S. states' Wildlife Action Plans developed under the Congressional Wildlife Conservation and Restoration Program. We find that these criteria yield modest improvements over the FWS's current allocations and that documented inconsistencies in these allocations do not have a detrimental impact on the effectiveness of conservation spending. We also find that alternative policy goals—promoting recovery or preventing extinction—imply a tradeoff between increasing the number of Improving species and reducing the number of Extinct species of roughly 2:1.
Developing Variable Unit‐Structure Premium Rate Differentials in Crop Insurance
Authors: Knight Thomas O. , Coble Keith H. , Goodwin Barry K. , Rejesus Roderick M. , Seo Sangtaek
Published: January 2010

Federal crop insurance programs offer producers the option of insuring farm units individually or as an aggregate unit. Existing programs offer a fixed 10% discount for most growers taking coverage at the aggregate level. This article describes an analysis of risk changes when units are aggregated. The methods described here, which base unit aggregation discounts on observable farm characteristics, are approved for implementation into the Federal Crop Insurance Program.
Are Intraday Volume and Volatility U‐Shaped After Accounting for Public Information?
Authors: Eaves James , Williams Jeffrey
Published: January 2010

No matter how pronounced intraday patterns may appear, it is difficult to account for cross‐correlations among related assets when those assets trade continuously and simultaneously. Futures contracts are auctioned periodically and sequentially on the Tokyo Grain Exchange (TGE). Even though intraday TGE volume is U‐shaped, intraday volatility is closer to L‐shaped. After accounting for the public information in immediately preceding auctions for the same commodity, for earlier trading in other commodities, and for trading on overseas markets open overnight in Tokyo, the intraday patterns are effectively flat. Thus, the timing of privately informed traders cannot be the source of intraday patterns.
Meat Meets Meta: A Quantitative Review of the Price Elasticity of Meat
Authors: Gallet Craig A.
Published: January 2010

The price elasticity of meat has been estimated in numerous studies that utilize a variety of disparate modeling procedures. In light of differences in the literature, a meta‐analysis is performed to assess the sensitivity of the meat price elasticity to a number of characteristics, including the type of meat, specification of demand, nature of data, estimation method, characteristics of the publication outlet, and location of demand. The results from estimating linear and Box‐Cox meta‐regressions, coupled with different panel data treatments, reveal that these characteristics have differing influence on the reported price elasticity.
Technology Adoption and Technical Efficiency: Organic and Conventional Dairy Farms in the United States
Authors: Mayen Carlos D. , Balagtas Joseph V. , Alexander Corinne E.
Published: January 2010

We compare productivity and technical efficiency of organic and conventional dairy farms in the United States. We address self‐selection into organic farming by using propensity score matching and explicitly test the hypothesis that organic and conventional farms employ a single, homogeneous technology. Utilizing the 2005 Agricultural Resource Management Survey on Dairy Costs and Returns Report (ARMS) data, we reject the homogeneous technology hypothesis and find that the organic dairy technology is approximately 13% less productive. However, we find little difference in technical efficiency between organic and conventional farms when technical efficiency is measured against the appropriate technology.
Revisiting the Evaluation of Robust Regression Techniques for Crop Yield Data Detrending
Authors: Finger Robert
Published: January 2010

Using a Monte Carlo experiment, the performance of the ordinary least squares (OLS) and the MM‐estimator, a robust regression technique, is compared in an application of crop yield detrending. Assuming symmetric as well as skewed crop yield distributions, we show that the MM‐estimator performs similarly to OLS for uncontaminated time series of crop yield data, and clearly outperforms OLS for outlier‐contaminated samples. In contrast to earlier studies, our analysis suggests that robust regression techniques, such as the MM‐estimator, should be reconsidered for detrending crop yield data.
The Effect of Strict Agricultural Zoning on Agricultural Land Values: The Case of Ontario's Greenbelt
Authors: Deaton B. James , Vyn Richard J.
Published: January 2010

In 2004, the provincial government of Ontario passed legislation that imposed a moratorium on urban development of agricultural land within a “Greenbelt” boundary.  This legislation, which became known as the Greenbelt legislation, has a direct effect on over 1.8 million acres of land located near one of the larger metropolitan areas in North America: the Greater Toronto Area.  We use a hedonic model to examine 7760 farmland sales and we find evidence that the Greenbelt legislation influenced farmland property prices; the effect depends on the proximity of the farmland to the Greater Toronto Area.
The Role of Theoretical Restrictions in Forecasting with Inverse Demand Models
Authors: Klaiber H. Allen , Holt Matthew T.
Published: January 2010

In recent years, the theoretical restrictions of consumer demand have been examined in post‐sample forecasting exercises. However, this work has uniformly ignored associated curvature restrictions. In this paper we evaluate a series of Normalized Quadratic Inverse Demand System (NQIDS) specifications by using rolling windows and generating one‐ to four‐step ahead forecasts. Data for eleven categories of South Atlantic fish spanning 1980 through 2001 are used in estimation. In addition to the NQIDS, we also examine the forecasting performance of a Cobb–Douglas model with autoregressive errors. We find that the best predictions are achieved using a composite forecast.
Medical Student Attitudes toward Complementary, Alternative and Integrative Medicine
Authors: Abbott Ryan B. , Hui Ka-Kit , Hays Ron D. , Mandel Jess , Goldstein Michael , Winegarden Babbi , Glaser Dale , Brunton Laurence
Published: January 2010

While the use of complementary, alternative and integrative medicine (CAIM) is substantial, it continues to exist at the periphery of allopathic medicine. Understanding the attitudes of medical students toward CAIM will be useful in understanding future integration of CAIM and allopathic medicine. This study was conducted to develop and evaluate an instrument and assess medical students′ attitudes toward CAIM. The Complementary, Alternative and Integrative Medicine Attitudes Questionnaire (CAIMAQ) was developed by a panel of experts in CAIM, allopathic medicine, medical education and survey development. A total of 1770 CAIMAQ surveys (51% of US medical schools participated) were obtained in a national sample of medical students in 2007. Factor analysis of the CAIMAQ revealed five distinct attitudinal domains: desirability of CAIM therapies, progressive patient/physician health care roles, mind‐body‐spirit connection, principles of allostasis and a holistic understanding of disease. The students held the most positive attitude for the “mind‐body‐spirit connection” and the least positive for the “desirability of CAIM therapies”. This study provided initial support for the reliability of the CAIMAQ. The survey results indicated that in general students responded more positively to the principles of CAIM than to CAIM treatment. A higher quality of CAIM‐related medical education and expanded research into CAIM therapies would facilitate appropriate integration of CAIM into medical curricula. The most significant limitation of this study is a low response rate, and further work is required to assess more representative populations in order to determine whether the relationships found in this study are generalizable.
Apolipoproteins in the discrimination of atherosclerotic burden and cardiac function in patients with stable coronary artery disease
Authors: Patel Jeetesh V. , Abraheem Abraheem , Creamer John , Gunning Mark , Hughes Elizabeth A. , Lip Gregory Y.H.
Published: January 2010

Aims

To compare the performance of apolipoproteins (Apo) and oxidized LDL against routine clinical lipid profiles in the discrimination of atherosclerotic burden and cardiac function in stable coronary artery disease (CAD) patients.

Methods and results

Using a cross‐sectional approach, we measured oxidized LDL, Apo AI and B in 199 patients (34–81 years) with stable symptomatic CAD. The discrimination of (i) atherosclerotic burden (coronary atheroma scores, the number of diseased coronary vessels), and (ii) cardiac function [NYHA classification, left‐ventricular systolic dysfunction (LVSD)] were judged using receiver operating characteristic (ROC) curves. The ratio of Apo AI to B was correlated to oxidized LDL (Spearman, r = 0.37, P < 0.001); however, oxidized LDL was unrelated to measures of cardiac function or CAD severity. Concentrations of Apo AI decreased from 1.38 to 1.20 g/L with increasing atheroma scores (P = 0.02), while triglyceride levels increased from 1.50 to 2.23 mmol/L (P = 0.016). High‐density lipoprotein (HDL) cholesterol and Apo AI levels were higher among those with heart failure (P = 0.002), and increased ordinally with NYHA class (P = 0.005). On ROC analysis, reduced levels of Apo AI and HDL cholesterol were discriminators for patients in the upper quartile for atheroma score (P < 0.004). Raised indices of HDL were associated with heart failure (P < 0.002).

Conclusion

Apo AI levels are a consistent discriminator of atherosclerotic burden among patients with stable CAD. However, heart failure presents an element of confounding in the diagnostic and prognostic utility of Apo monitoring among these patients.
Sutureless Aortic Valve Replacement via Partial Sternotomy
Authors: Martens Sven , Zierer Andreas , Ploss Anja , Sirat Sami , Miskovic Aleksandra , Moritz Anton , Doss Mirko
Published: January 2010

Objective

For elderly patients with symptomatic aortic valve stenosis, aortic valve replacement with tissue valves is still the treatment of choice. Stentless valves were introduced to clinical practice for better hemodynamic features as compared with stented tissue valves. However, the implantation is more complex and time demanding, especially in minimal invasive aortic valve replacement. We present our clinical data on 22 patients having received a sutureless ATS 3f Enable aortic bioprosthesis via partial upper sternotomy.

Methods

The procedure was performed using CPB with cardioplegic arrest. After resection of the stenotic aortic valve and debridement of the annulus, the valve was inserted and released. Mean age was 79 years, and mean logistic Euroscore was 13. Subvalvular myectomy was performed in two patients. Prosthetic valve sizes were 19 mm (n = 1), 21 mm (n = 7), 23 mm (n = 6), 25 mm (n = 6), and 27 mm (n = 2).

Results

Implantation of the valve required 10 ± 6 minutes. Cardiopulmonary bypass and aortic crossclamp time were 87 ± 16 and 55 ± 11 minutes, respectively. Early mortality (<90 days) was 9% (2 patients). No paravalvular leakage was detected intraoperatively or in follow-up echocardiography. The mean transvalvular gradients were 9 ± 6 mm Hg at discharge and 8 ± 2 mm Hg at 1-year follow-up.

Conclusions

Sutureless valve implantation via partial sternotomy is feasible and safe with the ATS 3f Enable bioprosthesis. Reduction of cardiopulmonary bypass and aortic crossclamp time seems possible with increasing experience. Hemodynamic data are very promising with low gradients at discharge and after 12 month. Sutureless valve implantation via minimal invasive access may be an alternative treatment option for elderly patients with high comorbidity.
Acute Feasibility Study of a Novel Device for the Treatment of Mitral Regurgitation in a Normal Canine Model
Authors: Takaseya Tohru , Fumoto Hideyuki , Saraiva Roberto M. , Shiose Akira , Arakawa Yoko , Park Margaret , Rao Santosh , Dessoffy Raymond , Kramer Larry D. , Juravic Mark , Lombardi Pierluca , Fukamachi Kiyotaka
Published: January 2010

Objective

The purpose of this study was to evaluate the implantability of a novel epicardial mitral annuloplasty device and its ability to reduce the septal-lateral (S-L) dimension of the mitral annulus.

Methods

The devices were implanted on the beating heart in 2 healthy dogs (the 24-mm long device in dog A and the 27-mm and 24-mm standard devices in dog B) by sliding the anterior arm onto the floor of the transverse sinus and positioning the posterior arm just apical to the atrioventricular groove on the left ventricular posterolateral wall. The devices were secured with titanium helical tacks driven through the device into the ventricular wall. Two-dimensional epicardial echocardiograms were performed before and after device implantation to evaluate the degree of mitral regurgitation (MR) and the S-L dimension.

Results

Device implantation was uneventful, taking only ~30 seconds to deploy. MR (1 +) in both dogs at baseline was reduced to zero after implant. The reductions in S-L dimension in systole for the 24-mm device were 7.5% in dog A and 30.5% in dog B. For the 27-mm device in dog B, S-L reduction in systole was 29.9%. The leaflet coaptation length was increased in both cases.

Conclusions

The new device was effective in reducing S-L dimension and 1 + MR without requiring the use of cardiopulmonary bypass. We are currently evaluating this device for the treatment of MR in a rapid-pacing canine heart failure model.
Comparison of Minithoracotomy versus Sternotomy in 304 Consecutive Tricuspid Valve Operations
Authors: Lee Teng C. , Desai Bhargavi S. , Milano Carmelo , Jaggers James , Glower Donald D.
Published: January 2010

Objective

The relative outcomes of sternotomy versus thoracotomy for tricuspid valve operation were examined over a 22-year period.

Methods

Three hundred four consecutive patients undergoing tricuspid valve operation using right minithoracotomy (THORC group; n = 124) versus median sternotomy (STERN group; n = 180) between 1985 and 2007 were retrospectively analyzed. Minithoracotomy used a 6-cm incision with femoral venous cannulation and augmented venous return. Sternotomy patients undergoing aortic valve, coronary bypass, or other procedure not feasible through a right minithoracotomy were excluded.

Results

Both groups were similar except that STERN patients had an earlier operative year. Combined mitral and tricuspid valve operation was performed in 70% (214/304) of patients. The tricuspid valve was repaired in 59% (180/304) of patients. Previous sternotomy was present in 56% (171/304) of patients. The mean cardiopulmonary bypass times were longer in the THORC group (216 vs. 167 minutes, <P < 0.0001). THORC was associated with a lower 30-day mortality (2% vs. 11%, P = 0.007), less atrial fibrillation (18% vs. 34%, P = 0.0025), less renal failure (3% vs. 11%, P = 0.016), and shorter length of stay (11 vs. 15 days, P = 0.012), although these differences were less apparent in more recent years. Stroke (3% vs. 2%, P = 0.72), respiratory failure (7% vs. 31%, P = 0.06), and infection rates (11% vs. 16%, P = 0.25) were similar. Five-year survival was also similar (63% vs. 64%, P = 0.84).

Conclusions

Given the limitations of a large, retrospective experience, minithoracotomy versus sternotomy is associated with low short-term morbidity and mortality, with advantages of avoiding sternotomy and minimizing mediastinal dissection in an otherwise high-risk group of patients.
Behavioural asymmetry affects escape performance in a teleost fish
Authors: Dadda Marco , Koolhaas Wouter H. , Domenici Paolo
Published: January 2010

Escape performance is fundamental for survival in fish and most other animals. While previous work has shown that both intrinsic (e.g. size, shape) and extrinsic (e.g. temperature, hypoxia) factors can affect escape performance, the possibility that behavioural asymmetry may affect timing and locomotor performance in startled fish is largely unexplored. Numerous studies have found a relationship between brain lateralization and performance in several cognitive tasks. Here, we tested the hypothesis that behavioural lateralization may affect escape performance in a teleost, the shiner perch
Cymatogaster aggregata
. Escape responses were elicited by mechanical stimulation and recorded using high-speed video (250 Hz). A number of performance variables were analysed, including directionality, escape latency, turning rate and distance travelled within a fixed time. A lateralization index was obtained by testing the turning preference of each subject in a detour test. While lateralization had no effect on escape directionality, strongly lateralized fish showed higher escape reactivity, i.e. shorter latencies, which were associated with higher turning rates and longer distances travelled. Therefore, lateralization is likely to result in superior ability to escape from predator attacks, since previous work has shown that escape timing, turning rate and distance travelled are among the main determinants of escape success.
Diet effects on honeybee immunocompetence
Authors: Alaux Cédric , Ducloz François , Crauser Didier , Le Conte Yves
Published: January 2010

The maintenance of the immune system can be costly, and a lack of dietary protein can increase the susceptibility of organisms to disease. However, few studies have investigated the relationship between protein nutrition and immunity in insects. Here, we tested in honeybees (
Apis mellifera
) whether dietary protein quantity (monofloral pollen) and diet diversity (polyfloral pollen) can shape baseline immunocompetence (IC) by measuring parameters of individual immunity (haemocyte concentration, fat body content and phenoloxidase activity) and glucose oxidase (GOX) activity, which enables bees to sterilize colony and brood food, as a parameter of social immunity. Protein feeding modified both individual and social IC but increases in dietary protein quantity did not enhance IC. However, diet diversity increased IC levels. In particular, polyfloral diets induced higher GOX activity compared with monofloral diets, including protein-richer diets. These results suggest a link between protein nutrition and immunity in honeybees and underscore the critical role of resource availability on pollinator health.
On some remarkable properties of an extended thermodynamic model for dense gases and macromolecular fluids
Authors: Carrisi M. C. , Mele M. A. , Pennisi S.
Published: January 2010

Recently, the 14 moments model of extended thermodynamics for dense gases and macromolecular fluids has been considered and an exact solution, of the restrictions imposed by the entropy principle and that of Galilean relativity, has been obtained without using Taylor's expansions. Here, we prove the uniqueness of the above solution and exploit other pertinent conditions such as the convexity of the function
h
′ related to the entropy density, the problem of subsystems and the fact that the flux in the conservation law of mass must be the moment of order 1 in the conservation law of momentum. The results present interesting aspects which were not suspected when only approximated solutions of this problem were known.
On the stability and control of unicycles
Authors: Sharp Robin S.
Published: January 2010

A mathematical model of a unicycle and rider, with a uniquely realistic tyre force and moment representation, is set up with the aid of multibody modelling software. The rider’s upper body is joined to the lower body through a spherical joint, so that wheel, yaw, pitch and roll torques are available for control. The rider’s bandwidth is restricted by low-pass filters. The linear equations describing small perturbations from a straight-running state are shown, which equations derive from a parallel derivation yielding the same eigenvalues as obtained from the first method. A nonlinear simulation model and the linear model for small perturbations from a general trim (or dynamic equilibrium) state are constructed. The linear model is used to reveal the stability properties for the uncontrolled machine and rider near to straight running, and for the derivation of optimal controls. These controls minimize a cost function made up of tracking errors and control efforts. Optimal controls for near-straight-running conditions, with left/right symmetry, and more complex ones for cornering trims are included. Frequency responses of some closed-loop systems, from the former class, demonstrate excellent path-tracking qualities within bandwidth and amplitude limits. Controls are installed for path-following trials. Lane-change and clothoid manoeuvres are simulated, demonstrating good-quality tracking of longitudinal and lateral demands. Pitch torque control is little used by the rider, while yaw and roll torques are complementary, with the former being more useful in transients, while the latter has value also in steady states. Wheel torque is influential on lateral control in turning. Adaptive control by gain switching is used to enable clothoid tracking up to lateral accelerations greater than 1 m s
−2
. General control of the motions of a virtual or robotic unicycle will be possible through the addition of more comprehensive adaptation to the control scheme described.
Acoustic energy radiated by nonlinear spherical oscillations of strongly driven bubbles
Authors: Holzfuss Joachim
Published: January 2010

Based on the theory of F. Gilmore (Gilmore 1952The growth or collapse of a spherical bubble in a viscous compressible liquid) for radial oscillations of a bubble in a compressible medium, the sound emission of bubbles in water driven by high-amplitude ultrasound is calculated. The model is augmented to include expressions for a variable polytropic exponent, hardcore and water vapour. Radiated acoustic energies are calculated within a quasi-acoustic approximation and also a shock wave model. Isoenergy lines are shown for driving frequencies of 23.5 kHz and 1 MHz. Together with calculations of stability against surface wave oscillations leading to fragmentation, the physically relevant parameter space for the bubble radii is found. Its upper limit is around 6 μm for the lower frequency driving and 1–3 μm for the higher. The radiated acoustic energy of a single bubble driven in the kilohertz range is calculated to be of the order of 100 nJ per driving period; a bubble driven in the megahertz range reaches two orders of magnitude less. The results for the first have applications in sonoluminescence research. Megahertz frequencies are widely used in wafer cleaning, where radiated sound may be implicated as responsible for the damage of nanometre-sized structures.
Potential role for lipopolysaccharide in congenital sensorineural hearingloss
Authors: Smit A. L. , Stokroos R. J. , Litjens S. G. H. , Kremer B. , Kramer B. W.
Published: January 2010

Congenital sensorineural hearing loss (SNHL) is common. In theWestern world, the incidence is 1–3 per 1000 live births. The aetiologyencompasses genetic and non-genetic factors accounting for 55 %and 45 % of cases, respectively. Reports that describe the contributionof intrauterine infection to the occurrence of congenital SNHL are limited,and comparative analysis of the different pathogens is lacking. Lipopolysaccharide (LPS),a product of bacteriolysis, has been demonstrated to be associated with innerear damage in experimental studies. To elucidate the potential role of thistoxin in congenital SNHL and to identify the pathogenesis and transmissionroutes, we reviewed the literature. We speculate that different routes ofexposure to LPSin uteromay result in congenital inner ear damage.
Characterization of multidrug-resistant Escherichia coli isolated from extraintestinal clinical infections in animals
Authors: Gibson Justine S. , Cobbold Rowland N. , Trott Darren J.
Published: January 2010

Multidrug-resistant (MDR)Escherichia colicauses extraintestinal infections in both humans and animals. This study aimed to determine whether MDRE. coliisolates cultured from extraintestinal infections in several animal species were clonal and crossed host-species boundaries, as suggested by initial characterization of a subset of canine and human isolates, or whether they represented a diverse group of host-specific strains. Isolates were obtained either from The University of Queensland Veterinary Diagnostic Laboratory or from an independent diagnostic laboratory between October 1999 and December 2007. Ninety-six MDRE. coliisolates cultured from extraintestinal clinical infections in 55 animals comprising dogs (n=45), cats (n=5), horses (n=4) and a koala (n=1) were analysed by phylogenetic grouping, antimicrobial susceptibility testing and PFGE. The isolates were cultured from the urinary tract (n=61), reproductive tract (n=11), wounds (n=11), surgical site infections (n=4) and other sites (n=9). Isolates from the sameE. coliphylogenetic group with 100 % PFGE similarity and the same antimicrobial susceptibility pattern were considered to be repeat clones and excluded from further analysis. Three of the fourE. coliphylogenetic groups (A,n=19; B1,n=8; and D,n=49) were represented. Analysis of PFGE similarity identified clusters of related phylogenetic group A isolates [clonal group (CG) 1] and group D isolates (CG2 and CG3), with the remainder of the isolates demonstrating diversity. The majority of CG2 isolates contained a plasmid-borne AmpCβ-lactamase, imparting resistance to cefoxitin and third-generation cephalosporins, and were obtained between 2000 and 2003. CG3 isolates were sensitive to these antimicrobial agents and appeared to replace CG2 isolates as the dominant clones from 2003 to 2007. Apart from several canine and feline isolates that demonstrated clonality, PFGE profiles tended to be divergent across species. Whilst MDRE. coliisolates from extraintestinal infections in different animal species are diverse, some dominant CGs may persist over several years.
A complex regulatory network controls aerobic ethanol oxidation in Pseudomonas aeruginosa: indication of four levels of sensor kinases and response regulators
Authors: Mern Demissew S. , Ha Seung-Wook , Khodaverdi Viola , Gliese Nicole , Görisch Helmut
Published: January 2010

In addition to the known response regulator ErbR (former AgmR) and the two-component regulatory system EraSR (former ExaDE), three additional regulatory proteins have been identified as being involved in controlling transcription of the aerobic ethanol oxidation system in Pseudomonas aeruginosa. Two putative sensor kinases, ErcS and ErcS′, and a response regulator, ErdR, were found, all of which show significant similarity to the two-component flhSR system that controls methanol and formaldehyde metabolism in Paracoccus denitrificans. All three identified response regulators, EraR (formerly ExaE), ErbR (formerly AgmR) and ErdR, are members of the luxR family. The three sensor kinases EraS (formerly ExaD), ErcS and ErcS′ do not contain a membrane domain. Apparently, they are localized in the cytoplasm and recognize cytoplasmic signals. Inactivation of gene ercS caused an extended lag phase on ethanol. Inactivation of both genes, ercS and ercS′, resulted in no growth at all on ethanol, as did inactivation of erdR. Of the three sensor kinases and three response regulators identified thus far, only the EraSR (formerly ExaDE) system forms a corresponding kinase/regulator pair. Using reporter gene constructs of all identified regulatory genes in different mutants allowed the hierarchy of a hypothetical complex regulatory network to be established. Probably, two additional sensor kinases and two additional response regulators, which are hidden among the numerous regulatory genes annotated in the genome of P. aeruginosa, remain to be identified.
The Stromal Chloroplast Deg7 Protease Participates in the Repair of Photosystem II after Photoinhibition in Arabidopsis
Authors: Sun Xuwu , Fu Tingjiao , Chen Ning , Guo Jinkui , Ma Jinfang , Zou Meijuan , Lu Congming , Zhang Lixin
Published: January 2010

Light is the ultimate source of energy for photosynthesis; however, excessive light leads to photooxidative damage and hence reduced photosynthetic efficiency, especially when combined with other abiotic stresses. Although the photosystem II (PSII) reaction center D1 protein is the primary target of photooxidative damage, other PSII core proteins are also damaged and degraded. However, it is still largely unknown whether degradation of D1 and other PSII proteins involves previously uncharacterized proteases. Here, we show that Deg7 is peripherally associated with the stromal side of the thylakoid membranes and that Deg7 interacts directly with PSII. Our results show that Deg7 is involved in the primary cleavage of photodamaged D1, D2, CP47, and CP43 and that this activity is essential for its function in PSII repair. The double mutants deg5 deg7 and deg8 deg7 showed no obvious phenotypic differences under normal growth conditions, but additive effects were observed under high light. These results suggest that Deg proteases on both the stromal and luminal sides of the thylakoid membranes are important for the efficient PSII repair in Arabidopsis (Arabidopsis thaliana).
Structure analysis of endosialidase NF at 0.98 Å resolution
Authors: Schulz Eike C. , Neumann Piotr , Gerardy-Schahn Rita , Sheldrick George M. , Ficner Ralf
Published: January 2010

Endosialidase NF (endoNF) is a bacteriophage-derived endosialidase that specifically degrades α-2,8-linked polysialic acid. The structure of a new crystal form of endoNF in complex with sialic acid has been refined at 0.98 Å resolution. The 210 kDa homotrimeric multi-domain enzyme displays outstanding stability and resistance to SDS. Even at atomic resolution, only a minor fraction of side chains possess alternative conformations. However, multiple conformations of an active-site residue imply that it has an important catalytic function in the cleavage mechanism of polysialic acid.
Studies on a Tyr residue critical for the binding of coenzyme and substrate in mouse 3(17)α-hydroxysteroid dehydrogenase (AKR1C21): structure of the Y224D mutant enzyme
Authors: Dhagat Urmi , Endo Satoshi , Mamiya Hiroaki , Hara Akira , El-Kabbani Ossama
Published: January 2010

Mouse 3(17)α-hydroxysteroid dehydrogenase (AKR1C21) is the only aldo–keto reductase that catalyzes the stereospecific reduction of 3- and 17-ketosteroids to the corresponding 3(17)α-hydroxysteroids. The Y224D mutation of AKR1C21 reduced theKmvalue for NADP(H) by up to 80-fold and completely reversed the 17α stereospecificity of the enzyme. The crystal structure of the Y224D mutant at 2.3 Å resolution revealed that the mutation resulted in a change in the conformation of the flexible loop B, including the V-shaped groove, which is a unique feature of the active-site architecture of wild-type AKR1C21 and is formed by the side chains of Tyr224 and Trp227. Furthermore, mutations (Y224F and Q222N) of residues involved in forming the safety belt for binding of the coenzyme showed similar alterations in kinetic constants for 3α-hydroxy/3-ketosteroids and 17-hydroxy/ketosteroids compared with the wild type.
Managing construction waste on‐site through system dynamics modelling: the case of Hong Kong
Authors: Li Hao Jian , Hill Martyn James , Yin Shen Li
Published: January 2010

Purpose

The purpose of this paper is to provide a decision support tool for construction waste on‐site to achieve better construction and demolition waste management.

Design/methodology/approach

System dynamics methodology is adopted for developing the model.

Findings

The model of managing construction waste on‐site is established. The interconnections of the main activities are included into the model with focus on planning and management where information about the future trend is for better decision making.

Practical implications

Construction waste generation is dynamic and interactive. Therefore, the model developed can be used as a flexible tool to help practitioners to understand the causes and effects.

Originality/value

Since the model allows the users to fine‐tune the input parameters, it is flexible to adjust the model to better reflect the reality according to different conditions. This is an advantage over other static models.
Lessons learned from a case study in deploying blended learning continuing professional development
Authors: Wall John , Ahmed Vian
Published: January 2010

Purpose

This paper seeks to propose a framework for higher education institutions facing the challenge of developing and deploying continuing professional development in the construction industry using a blended learning approach. The focus in on institutions that have not previously engaged in delivery of programmes using a combination of both traditional and distance learning formats.

Design/methodology/approach

Drawing on literature on the use of technology in the delivery of lifelong learning, a case analysis of a newly deployed blended learning programme is presented.

Findings

This paper illustrates that construction professionals undertaking blended learning programmes can engage with a range of ICT technologies and the integration of these technologies can make for an effective programme.

Research limitations/implications

The case study is limited by its small and potentially non‐representative sample and should be viewed as a first step in the formulation of a framework for deploying continuing professional development.

Originality/value

Professionals in the construction industry who wish to access lifelong learning opportunities face many challenges in trying to access programmes while continuing to meet work and personal commitments. A framework for educational providers to deliver blended lifelong learning in the construction industry based on the analysis of this initiative is put forward.
Strategic safety management information system for building projects in Singapore
Authors: Kamardeen Imriyas
Published: January 2010

Purpose

The construction industry in Singapore has been recording higher accident rates compared with other industries. As an initiative to reduce occupational accidents, the Building and Construction Authority of Singapore proposed to clients to adopt quality‐fee method (QFM) for tender evaluation, departing from the traditional lowest price method. Assessing tenderers' safety proposals is a crucial task for clients' project managers to implement QFM, but it is a difficult and challenging task. This study aims to provide a tool to facilitate this.

Design/methodology/approach

A triple‐index model was developed for estimating potential accident risks in building projects, given that a contractor's proposed safety system is in place to combat the accident hazards inherent in the project. The model was then automated as a decision support system (DSS). Case studies were conducted to test the reliability and accuracy of the DSS.

Findings

The DSS produces project accident indices, and it was found in the case studies that values for this index are positively correlated with the number of accidents in building projects. The findings proved that the DSS makes a significant contribution to the state‐of‐the‐art of risk assessment.

Practical implications

The proposed model and its DSS would facilitate the implementation of QFM for tender evaluation and thereby reduce accidents.

Originality/value

The paper presents a novel tool to combat accidents in construction at the early stage of tender evaluation.
Measuring knowledge retention: a case study of a construction consultancy in the UAE
Authors: Arif Mohammed , Egbu Charles , Alom Ola , Khalfan Malik M.A.
Published: January 2010

Purpose

The purpose of this paper is to develop a model that can be used to assess the knowledge retention capabilities of an organisation, and suggest opportunities for improvement. A model to fulfil this aim is developed and validated on a construction engineering consultancy.

Design/methodology/approach

A knowledge retention model was developed drawing on a thorough review of the literature. The developed retention model was validated through a case of a construction engineering consultancy. Semi‐structured interviews were used to elicit relevant information during the case study.

Findings

A four‐stage knowledge retention process has been presented. These four steps are socialisation, codification, knowledge construction, and knowledge retrieval. The paper also describes four levels of maturity for the knowledge retention model. The first level demonstrated the extent of knowledge sharing in the organisation, the second level measured the extent of knowledge shared being documented, the third level measured the effectiveness of storage of documented knowledge, and the last level was a measure of ease of accessibility and retrieval of the knowledge. A four‐level indicator of maturity of the knowledge retention process has been documented. For the case study analysed in this research, the maturity of knowledge retention was noted as being between two and three.

Research limitations/implications

The model developed only captures knowledge that can be converted into an explicit form. The authors accept that there would be some tacit knowledge that cannot be effectively codified in explicit form, and such knowledge might not be captured using the model.

Originality/value

The paper has developed a model that can be used to measure the knowledge retention in an organisation. Although the model has been applied to a construction industry, it can easily be modified vis‐à‐vis other sectors.
A survey on communications in large‐scale construction projects in China
Authors: Tai S. , Wang Y. , Anumba C.J.
Published: January 2010

Purpose

The purpose of this paper is to show how effective project team communications is one of the major challenges to a construction project's success. The success of large‐scale construction projects is critical to Chinese economy. The purposes of the research are to grasp the current status of communications in large‐scale construction projects in China and lay a basis for further research on project communications.

Design/methodology/approach

A survey was conducted by postal questionnaire and telephone.

Findings

Through analyzing the data obtained from the survey, the communication problems in large‐scale construction projects in China are exposed. The roots of the problems are summarized as lack of good communication mechanism, weak organizational structures of construction teams, lack of uniform standards for construction information, and lack of support for advanced communication technologies.

Originality/value

The paper presents the directions for further research to improve communications in large‐scale construction projects in China.