bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptive backstepping control for a class of time delay systems with nonlinear perturbations
Authors: Hua Chang‐Chun , Wang Qing‐Guo , Guan Xin‐Ping 
Published: June 2007

AbstractThe sliding mode control method has been extensively employed to stabilize time delay systems with nonlinear perturbations. Although the resulting closed‐loop systems have good transient and steady‐state performances, the designed controllers are dependent on the time delays. But one knows that it is difficult to obtain the precise delay time in practical systems, especially when it is time varying. In this paper, we revisit the problem and use the backstepping method to construct the state feedback controller. First, a coordinate transformation is used to obtain a cascade time delay system. Then, a linear virtual control law is designed for the first subsystem. The memoryless controller is further constructed based on adaptive method for the second subsystem with the uncertainties bounded by linear function. By choosing new Lyapunov–Krasovskii functional, we show that the system state converges to zero asymptotically. Via the proposed approach, we also discuss the case that the uncertainties are bounded by nonlinear functions. Finally, simulations are done to verify the effectiveness of the main results obtained. Copyright © 2007 John Wiley & Sons, Ltd.
A kriging method for the solution of nonlinear programs with black‐box functions
Authors: Davis Eddie , Ierapetritou Marianthi 
Published: June 2007

AbstractIn this article, a new methodology is developed for the optimization of black‐box systems lacking a closed‐form mathematical description. To properly balance the computational cost of building the model against the probability of convergence to global optimum, a hybrid methodology is proposed. A kriging approach is first applied to provide information about the global behavior of the system considered, whereas a response surface method is considered close to the optimum to refine the set of candidate local optima and find the global optimum. The kriging predictor is a global model employing normally distributed basis functions, so both an expected sampling value and its variance are obtained for each test point. The presented work extends the capabilities of existing response surface techniques to address the refinement of optima located in regions described by convex asymmetrical feasible regions containing arbitrary linear and nonlinear constraints. The performance of the proposed algorithm is compared to previously developed stand‐alone response surface techniques and its effectiveness is evaluated in terms of the number of function calls required, number of times the global optimum is found, and computational time. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Highly Luminescent, Neutral, Nine‐Coordinate Lanthanide(III) Complexes
Authors: Kottas Gregg S. , Mehlstäubl Marita , Fröhlich Roland , De Cola Luisa 
Published: June 2007

AbstractUsing a simple ligand design, we have prepared neutral, nine‐coordinate lanthanide complexes that exclude water from the inner coordination sphere, thus leading to high emission quantum yields and long excited‐state lifetimes. The complexes form in high synthetic yields (49–87 %) by simply mixing the ligand and the lanthanide. Visible luminescence from EuIII (Φ = 60 %, τ = 2.2 ms) and TbIII (Φ = 7 %, τ = 0.2 ms) and near‐infrared luminescence from YbIII (Φ = 0.7 %), NdIII and ErIII were observed in acetonitrile and CH2Cl2 at room temperature. In addition, the GdIII complex was prepared to gain information about the triplet state of the ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Peptidomimetics, Glycomimetics and Scaffolds from Carbohydrate Building Blocks
Authors: Murphy Paul V. 
Published: June 2007

AbstractSaccharides, due to their high density of functional groups and availability as chiral building blocks are scaffolds for bioactive compound discovery. Pyranosides and iminosugar‐based peptidomimetics have been synthesised as ligands for somatostatin receptors and HIV protease. The synthesis of polyhydroxylated macrolides related to natural products and cyclophanes has been achieved from carbohydrate fragments with a view to investigation of their potential as scaffolds. In addition, the trajectory of aromatic systems grafted to saccharides have been studied and this has led to the synthesis of probes for the study of carbohydrate protein interactions. These compounds include geometrically diverse bivalent glycomimetics derived from scaffolds that are hybrids of sugars and aromatic groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
QM/MM study of catalytic methyl transfer by the N5‐glutamine SAM‐dependent methyltransferase and its inhibition by the nitrogen analogue of coenzyme
Authors: Wu Ruibo , Cao Zexing 
Published: June 2007

AbstractThe combined density functional quantum mechanical/molecular mechanical (QM/MM) approach has been used to investigate methyl‐transfer reactions catalyzed by the N5‐glutamine S‐adenosyl‐L‐methionine (SAM)‐dependent methyltransferase (HemK) and the coenzyme‐modified HemK with the replacement of SAM by a nitrogen analogue. Calculations reveal that the catalytic methyl transfer by HemK is an energy‐favored process with an activation barrier of 15.7 kcal/mol and an exothermicity of 12.0 kcal/mol, while the coenzyme‐modified HemK is unable to catalyze the methyl transfer because of a substantial barrier of 20.6 kcal/mol and instability of the product intermediate. The results lend support to the experimental proposal that the nitrogen analogue of the SAM coenzyme should be a practicable inhibitor for the catalytic methyl transfer by HemK. Comparative QM/MM calculations show that the protein environment, especially the residues Asn197 and Pro198 in the active site, plays a pivotal role in stabilizing the transition state and regulating the positioning of reactive groups. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Selective asymmetry in a conserved forebrain to midbrain projection
Authors: Kuan Yung‐Shu , Gamse Joshua T. , Schreiber Alexander M. , Halpern Marnie E. 
Published: June 2007

AbstractHow the left and right sides of the brain acquire anatomical and functional specializations is not well understood. The zebrafish has proven to be a useful model to explore the genetic basis of neuroanatomical asymmetry in the developing forebrain. The dorsal diencephalon or epithalamus consists of the asymmetric pineal complex and adjacent paired nuclei, the left and right medial habenulae, which in zebrafish larvae, exhibit differences in their size, neuropil density and patterns of gene expression. In all vertebrates, axons from the medial habenular nuclei project within a prominent fiber bundle, the fasciculus retroflexus, to a shared midbrain target, the interpeduncular nucleus of the ventral tegmentum. However, in zebrafish, projections from the left habenula innervate the dorsal and ventral regions of the target nucleus, whereas right habenular efferents project only to the ventral region. A similar dorsoventral difference in habenular connectivity is found in another teleost species, the highly derived southern flounder, Paralichthys lethostima. In this flatfish, directional asymmetry of the habenular projection appears to be independent of the left–right morphology and orientation that an individual adopts post‐metamorphosis. Comparative anterograde labeling of the brains of salamanders, frogs and mice reveals that axons emanating from the left and right medial habenulae do not project to different domains, but rather, they traverse the target nucleus in a complementary mirror image pattern. Thus, although the habenulo‐interpeduncular conduction system is highly conserved in the vertebrate brain, the stereotypic dorsoventral topography of left–right connections appears to be a feature that is specific to teleosts. J. Exp. Zool. (Mol. Dev. Evol.) 308B:669–678, 2007. © 2007 Wiley‐Liss, Inc.
Tools and techniques for transferring know‐how from boomers to gamers
Authors: Kapp Karl M. 
Published: June 2007

AbstractHow well boomers transfer their knowledge to younger employees (gamers∥ may well determine which organizations maintain their competitive edge during the next decade. But boomers' and gamers' preferred learning styles are as different as night and day, and conventional approaches may hinder rather than aid knowledge transfer. Fortunately, companies can learn a lot from gamers about sharing knowledge. Instant messaging, blogs, wikis, RSS feeds, and podcasts—technologies gamers already use extensively outside the work environment to obtain information—are efficient, low‐cost tools for informal learning that companies can incorporate into an enterprise strategy for capturing and distributing business‐ and job‐critical know‐how before it's too late. © 2007 Karl M. Kapp.
Calculation of vibration transmission over bedrock using a waveguide finite element model
Authors: Peplow A. T. , Finnveden S. 
Published: June 2007

AbstractA finite element method is developed for the study of elastic wave propagation in layered ground environments. The formulation is based on a spectral finite‐element approach using a mixture of high‐order element shape functions and wave solutions. The numerical method provides solutions to vibration transmission on and within layered elastic waveguides. Examples of its use include the theoretical analysis of transmission of vibrations in the vicinity of the surface of the ground. The mathematical model is two dimensional, and the interior of the ground is modelled as an elastic layer overlying a rigid foundation. An analysis of the natural modes of free vibration in a single layer and two layers is presented and compared with known results. In addition the forced response of the layers, for which the surface is assumed to be subjected to a harmonic point force load is shown. These results also include an illustration of the attenuation of surface vibration due to ‘wave impedance blocks’ in the ‘near field’ of the source up to a frequency of 200 Hz for two soil types. Copyright © 2007 John Wiley & Sons, Ltd.
Untruthful probabilistic demand forecasts in vendor‐managed revenue‐sharing contracts: Coordinating the chain
Authors: Gerchak Yigal , Khmelnitsky Eugene , Robinson Lawrence W. 
Published: June 2007

AbstractVendor‐managed revenue‐sharing arrangements are common in the newspaper and other industries. Under such arrangements, the supplier decides on the level of inventory while the retailer effectively operates under consignment, sharing the sales revenue with his supplier. We consider the case where the supplier is unable to predict demand, and must base her decisions on the retailer‐supplied probabilistic forecast for demand. We show that the retailer's best choice of a distribution to report to his supplier will not be the true demand distribution, but instead will be a degenerate distribution that surprisingly induces the supplier to provide the system‐optimal inventory quantity. (To maintain credibility, the retailer's reports of daily sales must then be consistent with his supplied forecast.) This result is robust under nonlinear production costs and nonlinear revenue‐sharing. However, if the retailer does not know the supplier's production cost, the forecast “improves” and could even be truthful. That, however, causes the supplier's order quantity to be suboptimal for the overall system. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Numerical verification of solutions for Signorini problems using Newton‐like method
Authors: Ryoo Cheon Seoung 
Published: June 2007

AbstractWe proposed a numerical method to verify the existence of solutions for a simplified Signorini problem (Comput. Math. Appl. 2000; 40:1003–1013). Using sequential iteration method, we numerically constructed a set containing solutions that satisfies the hypothesis of Schauder's fixed point theorem in a certain Sobolev space. It is difficult to apply this method to the problem of which associated operator is not retractive in a neighborhood of the solution. In this paper, in order to overcome such a difficulty, we describe an alternative approach to this problem. Numerical examples are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Slug control in Australian canola: monitoring, molluscicidal baits and economic thresholds
Authors: Nash Michael A , Thomson Linda J , Hoffmann Ary A 
Published: June 2007

AbstractExotic slugs have become serious pests of canola, at establishment, in Southern Australian high‐rainfall cropping zones. Slugs were monitored using relatively inexpensive 300 mm × 300 mm terracotta tiles acting as refuges. An investigation was made of the effects of the time of application of chelated iron baits on the slug species Deroceras reticulatum Müller and Lehmannia nyctelia Bourguignat. Baits reduced the number of surface‐active slug species. A single application at sowing provided greater efficacy than one application before sowing, and efficacy was comparable with that of two applications. Canola seedling densities showed a negative response to D. reticulatum numbers; the presence of even one individual per refuge trap reduced seedling numbers below optimum densities. Thistles and other vegetation were associated with increased numbers of slugs. European guidelines for slug monitoring and damage appear to be at least partly applicable to Australian conditions. Copyright © 2007 Society of Chemical Industry
Patterns of fish diversity in a mainstem Missouri River reservoir and associated delta in South Dakota and Nebraska, USA
Authors: Kaemingk Mark A. , Graeb Brian D. S. , Hoagstrom Christopher W. , Willis David W. 
Published: June 2007

AbstractThere is an expansive and expanding delta at the confluence of the Niobrara and Missouri Rivers in the Lewis and Clark Reservoir. The delta provides diverse aquatic habitat that is somewhat similar to the historic Missouri River and to remnant river habitats. As such, the delta may have relatively high fish species diversity compared to lentic reservoir habitats. To compare patterns of fish diversity between the delta and reservoir habitats, we collected fish in several nursery habitats in both areas using four gear types (seine, gill net, electrofisher and fyke net) on three occasions (July, August and September) in 2005. Species richness was higher in the delta (n = 34) than the reservoir (n = 22). Thirteen species composed more than 1% of delta collections while only four species composed more than 1% of reservoir collections. Species diversity (Fisher's α) was also significantly higher in the delta. Higher species diversity in the delta may be explained by higher habitat diversity. These results suggest that newly forming deltas have the potential to protect and restore fish species diversity, because they retain natural river functions such as sediment transport and habitat formation. Copyright © 2007 John Wiley & Sons, Ltd.
Synthese und Festkörperstruktur des Koordinationspolymers {Zn[Sn(CH2SMe)4]0.5Cl2}n
Authors: Ruth Kai , Müller Manuela , Bolte Michael , Bats Jan W. , Wagner Matthias , Lerner Hans‐Wolfram 
Published: June 2007

AbstractSynthesis and Solid State Structure of the Coordination Polymer {Zn[Sn(CH2SMe)4]0.5Cl2}nThe tin compounds Sn(CH2SMe)4 and Sn(CH2PPh2)4 are accessible from reaction of SnCl4 with LiCH2SMe and LiCH2PPh2, respectively. X‐ray quality crystals of Sn(CH2PPh2)4 (tetragonal, ) are obtained from a benzene solution at 4 °C. The lithium methanide [Li(PMDTA)CH2PPh2], which was a starting material in the synthesis of Sn(CH2PPh2)4 crystallized from a mixture of diethyl ether and pentane at −20 °C in the monoclinic space group P21/c. The coordination polymer {Zn[Sn(CH2SMe)4]0.5Cl2}n was synthesized from Sn(CH2SMe)4 and ZnCl2 in benzene. The solid state structure of this coordination polymer reveals that {Zn[Sn(CH2SMe)4]0.5Cl2}n possesses an infinite [Zn‐SMe‐CH2‐Sn‐CH2‐SMe‐]‐chain as its backbone (monoclinic P21/c).
Intra-operative imaging in paediatric cardiac surgery: the reactions of parents who requested and watched a video of the surgery performed on their child
Authors: Kocyildirim Ergin , Franck Linda S. , Elliott Martin J. 
Published: June 2007

AbstractObjectiveOur previous work demonstrated that digital video recording of operations is the best way to describe the morphological features and complex dynamic physiology of surgical treatment of congenitally malformed hearts. Parental consent is required for video recording, and some parents have requested, and obtained, a copy of the video of the operation performed on their child. Our present aim was to explore their feelings and opinions having viewed the recording of the surgical procedures.Design and participantsThis exploratory study examined the views of 17 parents, comprising 7 couples, 2 mothers, and 1 father, after requesting, and then watching, the recording of the operation performed on their child. The audio-taped, semistructured interviews were analyzed for the thematic content.ResultsAll parents watched the videos at least once, and no parent exhibited distress as a result. Curiosity and desire for learning, and wanting to know what exactly happened to the child during the operation, were the most common reasons for requesting the video. Parents reported that the videos were also useful in sharing the experience with family and friends. The videos had no effect on the attitudes of the parents towards the surgical team. Parents made recommendations to increase the length of the edited videos and add labels and voice-overs.ConclusionParents of children with congenitally malformed hearts want to watch the recording of the operation performed because of their need for information, and to understand the experience of their children when separated from them. Research is needed to assess the potential value of operative videos in facilitating parental knowledge and coping when children undergo major cardiac surgery.
IP3 receptor antagonist, 2‐APB, attenuates cisplatin induced Ca2+‐influx in HeLa‐S3 cells and prevents activation of calpain and induction of apoptosis
Authors: Splettstoesser F , Florea A‐M , Büsselberg D 
Published: June 2007

Background and purpose:Cisplatin drives specific types of tumour cells to apoptosis. In this study we investigate the involvement of intracellular calcium ([Ca2+]i) in triggering apoptosis in two different cell lines. As cisplatin is used for the treatment of several forms of cancer we choose HeLa‐S3 and U2‐OS as two examples of tumour cell lines.Experimental approach:Cisplatin (1nM–10μM) was applied to HeLa‐S3 and U2‐OS cells and [Ca2+]i measured with fluo‐4, using laser scanning microscopy. Inositol‐1,4,5‐trisphosphate (IP3) receptors were visualized with immunostaining. Membrane conductances were measured with patch‐clamp techniques. Levels of calpain and caspases were assessed by western blots and apoptotic cells were stained with Hoechst 33342 and counted.Key results:Cisplatin increases [Ca2+]i concentration‐dependently in HeLa‐S3 but not in U2‐OS cells. This elevation of [Ca2+]i depended on extracellular Ca2+ but was reduced by the IP3 receptor blocker, 2‐APB. This effect was not due to a Ca2+ release triggered by Ca2+ entry. Immunostaining showed IP3‐receptors (type1‐3) at the cellular membrane of HeLa‐S3 cells, but not in U2‐OS cells. Electrophysiological experiments showed an increased membrane conductance with cisplatin only when Ca2+ was present extracellularly. Increase of [Ca2+]i was related to the activation of calpain but not caspase‐8 and triggered apoptosis in HeLa‐S3 but not in U2‐OS cells.Conclusions and implications:Our observations on the activation of IP3‐receptors, calcium entry and apoptotic rate by cisplatin in specific carcinogenic cells might open new possibilities in the treatment of some forms of cancer.British Journal of Pharmacology (2007) 151, 1176–1186; doi:10.1038/sj.bjp.0707335
Interaction of ligands for the peroxisome proliferator‐activated receptor γ with the endocannabinoid system
Authors: Lenman A , Fowler C J 
Published: June 2007

Background and purpose:There is good evidence that agents interacting with the endocannabinoid system in the body can also interact with the peroxisome proliferator‐activated receptorγ. The present study was designed to test whether the reverse is true, namely whether peroxisome proliferator‐activated receptorγligands have direct effects upon the activity of the endocannabinoid metabolizing enzyme fatty acid amide hydrolase.Experimental approach:Fatty acid amide hydrolase activity was measured in rat brain homogenates, C6 glioma and RBL2H3 basophilic leukaemia cells. Cellular uptake of anandamide was also assessed in these cells.Key results:Peroxisome proliferator‐activated receptorγactivators inhibited the metabolism of the endocannabinoid anandamide in rat brain homogenates with an order of potency MCC‐555 > indomethacin ≈ ciglitazone ≈ 15‐deoxy‐Δ12,14‐prostaglandin J2≈ pioglitazone > rosiglitazone > troglitazone. The antagonists BADGE, GW9662 and T0070907 were poor inhibitors of anandamide hydrolysis. The inhibition by ciglitazone was competitive and increased as the pH of the assay buffer was decreased; the Kivalue at pH 6.0 was 17μM. In intact C6 glioma cells assayed at pH 6.2, significant inhibition of anandamide hydrolysis was seen at 3μM ciglitazone, whereas 100μM was required to produce significant inhibition at pH 7.4. Ciglitazone also interacted with monoacylglycerol lipase as well as with cannabinoid CB1and CB2receptors.Conclusions and implications:Ciglitazone may be useful as a template for the design of novel dual action anti‐inflammatory agents which are both inhibitors of fatty acid amide hydrolase and agonists at the peroxisome proliferator‐activated receptorγ.British Journal of Pharmacology(2007)151, 1343–1351; doi:10.1038/sj.bjp.0707352
Thermodynamic analysis of ligands at cholecystokinin CCK2receptors in rat cerebral cortex
Authors: Harper E A , Roberts S P , Kalindjian S B 
Published: June 2007

Background and purpose:Several studies using radioligand binding assays, have shown that measurement of thermodynamic parameters can allow discrimination of agonists and antagonists (Weilandet al., 1979;Boreaet al., 1996a). Here we investigate whether agonists and antagonists can be thermodynamically discriminated at CCK2receptors in rat cerebral cortex.Experimental approach:The pKLof [3H]‐JB93182 in rat cerebral cortex membranes was determined at 4, 12, 21 and 37°C in 50 mMTris‐HCl buffer (buffer B pH 6.96; containing 0.089 mMbacitracin). pKIvalues of ligands of diverse chemical structure and with differing intrinsic activity (α), as defined by the lumen‐perfused rat and mouse stomach bioassays, were determined in buffer B at 4, 12, 21 and 37°C.Key results:[3H]‐JB93182 labelled a homogeneous population of receptors in rat cerebral cortex at 4, 12, 21 and 37°C and the pKLand Bmaxwere not altered by incubation temperature. [3H]‐JB93182 binding reached equilibrium after 10, 50, 90 and 220 min at 37, 21, 12 and 4°C, respectively. pKIvalues forR‐L‐365,260,R‐L‐740,093, YM220, PD134,308 and JB95008 were higher at 4°C than at 37°C. There was no effect of temperature on pKIvalues for pentagastrin, CCK‐8S,S‐L‐365,260, YM022, PD140,376 and JB93242.Conclusions and implications:CCK2receptor agonists and antagonists at rat CCK2receptors cannot be discriminated by thermodynamic analysis using [3H]‐JB93182 as the radioligand.British Journal of Pharmacology(2007)151, 1352–1367; doi:10.1038/sj.bjp.0707355