bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composite adaptive and input observer‐based approaches to the cylinder flow estimation in spark ignition automotive engines
Authors: Stotsky A. , Kolmanovsky I. , Eriksson S. 
Published: March 2004

AbstractThe performance of air charge estimation algorithms in spark ignition automotive engines can be enhanced using advanced estimation techniques available in the controls literature. This paper illustrates two approaches of this kind that can improve the cylinder flow estimation for gasoline engines without external exhaust gas recirculation (EGR). The first approach is based on an input observer, while the second approach relies on an adaptive estimator. Assuming that the cylinder flow is nominally estimated via aspeed‐densitycalculation, and that the uncertainty is additive to the volumetric efficiency, the straightforward application of an input observer provides an easy to implement algorithm that corrects the nominal air flow estimate. The experimental results that we report in the paper point to a sufficiently good transient behaviour of the estimator. The signal quality may deteriorate, however, for extremely fast transients. This motivates the development of an adaptive estimator that relies mostly on the feedforward speed‐density calculation during transients, while during engine operation close to steady‐state conditions, it relies mostly on the adaptation. In our derivation of the adaptive estimator, the uncertainty is modelled as an unknown parameter multiplying the intake manifold temperature. We use the tracking error between the measured and modelled intake manifold pressure together with an appropriately definedprediction error estimateto develop an adaptation algorithm with improved identifiability and convergence rate. A robustness enhancement, via a σ‐modification with the σ‐factor depending on the prediction error estimate, ensures that in transients the parameter estimate converges to a pre‐determineda priorivalue. In close to steady‐state conditions, the σ‐modification is rendered inactive and the evolution of the parameter estimate is determined by both tracking error and prediction error estimate. Further enhancements are made by incorporating a functional dependence of thea priorivalue on the engine operating conditions such as the intake manifold pressure. The coefficients of this function can belearnedduring engine operation from the values to which the parameter estimate converges in close to steady‐state conditions. This feedforward learning functionality improves transient estimation accuracy and reduces the convergence time of the parameter estimate. Copyright © 2004 John Wiley & Sons, Ltd.
Application of a multivariable adaptive control strategy to automotive air conditioning systems
Authors: Shah Rajat , P. Rasmussen Bryan , Alleyne Andrew G. 
Published: March 2004

AbstractThis paper presents the application of a multivariable adaptive control strategy to a typical automotive air conditioning system. An experimentally validated physical model for the air conditioning (a/c) cycle is first presented and is subsequently used to choose a relevant model structure for indirect adaptive control. Recursive identification of this model structure is carried out using a multi‐input multi‐output (MIMO) parameter estimation algorithm to obtain an equivalent discrete‐time state space model of the a/c system. Linear quadratic regulator (LQR) design is implemented on the estimated model with the objectives of reference tracking and disturbance rejection. Simulation studies are presented to evaluate the advantages of using the electronic expansion valve and the air flow rate over the evaporator to control the efficiency and the capacity of a general automotive a/c unit using this adaptive control approach. The results demonstrate the efficacy of the MIMO controller and motivate further research in this area. Copyright © 2004 John Wiley & Sons, Ltd.
Nanoröhrchen durch Templatbenetzung: ein Baukastensystem
Authors: Steinhart Martin , Wehrspohn Ralf B. , Gösele Ulrich , Wendorff Joachim H. 
Published: March 2004

AbstractDie Benetzung poröser Template mit Polymerschmelzen und ‐lösungen oder polymerhaltigen Mischungen ist eine ebenso einfache wie vielseitige Methode zur Herstellung von röhrchenförmigen Strukturen mit Durchmessern von wenigen zehn Nanometern bis in den Mikrometerbereich. Ihre Wände können dabei aus einer Vielzahl von Materialien bestehen, die bisher zum Teil nicht oder nur mit erheblichen Einschränkungen nanostrukturierbar waren. Beispiele sind Hochleistungspolymere wie Polytetrafluorethylen, Edelmetalle wie Palladium oder ferroelektrische Oxide. Die Methode ermöglicht eine vielfältige Modifizierung der Röhrchen, beispielsweise durch kontrollierte Erzeugung von Poren oder Einbettung von Nanopartikeln in die Röhrchenwände. Die Templatbenetzung bietet einen vielversprechenden Zugang zu funktionalisierten Nanoröhrchen‐Templat‐Hybridsystemen und freistehenden Nanoröhrchen.
Nanotubes by Template Wetting: A Modular Assembly System
Authors: Steinhart Martin , Wehrspohn Ralf B. , Gösele Ulrich , Wendorff Joachim H. 
Published: March 2004

AbstractThe wetting of porous templates with polymer melts and solutions or polymer‐containing mixtures is a simple and versatile method for the preparation of tubular structures with diameters ranging from a few tens of nanometers to micrometers. The tube walls can be made of a multitude of materials, some of which have thus far been altogether impossible to use or very limited in their ability to be incorporated into nanostuctures. Template wetting also makes it possible to modify the nanotubes in a variety of ways, for example through the controlled generation of pores or the embedding of nanoparticles into the walls. This method offers a promising approach to functionalized nanotube–template hybrid systems and free‐standing nanotubes.
Induction of myeloperoxidase and nitrotyrosine formation in a human eosinophilic leukemia cell line, EoL‐1
Authors: Kodama Norio , Kambayashi Yasuhiro , Kubo Masayuki , Nobukuni Yoshitaka , Kimura Shingo , Nakamura Hiroyuki , Ogino Keiki 
Published: March 2004

AbstractThe human eosinophilic leukemia cell line, EoL‐1, differentiated with butyrate as an eosinophilic cellular model was evaluated for peroxidase‐dependent tyrosine nitration. Butyrate suppressed cell growth and induced eosinophilic granules in EoL‐1 cells after 9 days of culture. Peroxidase activity was detected biochemically and histochemically from 3‐day cultures and it increased in a time dependent manner. This peroxidase activity was inhibited by cyanide. Nitrotyrosine formation catalysed by peroxidase using hydrogen peroxide and nitrite was detected at a high level similar to that of mature eosinophils. However, no expression of eosinophil peroxidase (EPO) was detected by RT‐PCR or immunocytochemistry. In contrast, the induction of myeloperoxidase (MPO) by butyrate was clearly detected by RT‐PCR, Northern blot, and immunocytochemical staining. These results suggest that butyrate induces MPO rather than EPO in EoL‐1 cells and that the formation of nitrotyrosine in butyrate‐induced cells is dependent on MPO. Copyright © 2003 John Wiley & Sons, Ltd.
The effects of dietary flaxseed on the Fischer 344 rat: I. Development, behaviour, toxicity and the activity of liver γ‐glutamyltranspeptidase
Authors: Hemmings Susan J. , Barker Lorraine 
Published: March 2004

AbstractThe effect of exposure to, followed by consumption of, 10% flax chow from the 18th day of gestation to the 86th day after birth was examined in male and female Fischer 344 rats. Growth curves of the flax chow‐fed rats were identical to those of regular chow‐fed rats, as were such developmental milestones as pinna development, growth of hair and eye opening. Acoustical startle and the righting reflexes, developmental behavioural indices, were also the same. Blood glucose levels were comparable in flax chow‐fed and regular chow‐fed rats at all stages of development, indicating that flax is without effect on glucose balance. There were no signs of toxicity in the flax chow‐fed rats since their plasma levels of alanine aminotransferase and γ‐glutamyltranspeptidase (γGT) were the same as those of regular chow‐fed rats. The activity of γGT displayed an increase in the livers of flax chow‐fed rats after puberty, more so in the male—four‐fold—than in the female—1.38‐fold. This is suggestive of an estrogenic effect which implicates an effect of an estrogenic flax lignan. An hepatobeneficial effect of the flax‐induced increase in liver γGT is discussed. In summary, dietary 10% flax chow is without long‐term effect on growth, development and behaviour, is non‐toxic and may be hepatoprotective. Copyright © 2003 John Wiley & Sons, Ltd.
The investigation of the ultrastructural neutrophil changes in alloxan‐induced diabetes in rats: response to a chemotactic challenge
Authors: Özsoy Nesrin , Bostancı Hamit , Ayvalı Cevat 
Published: March 2004

AbstractExperimental diabetes is one of the most popular conditions in which to study the relation between neutrophil leukocyte activity and periodontal destruction. The aetiology of neutrophil dysfunction in the gingival tissue associated with diabetes has yet to be clarified. Diabetes in rats decreases neutrophil chemotactic activity in proportion to the severity of this systemic disorder. The present study was carried out to evaluate the relationship between the severity of diabetes and the neutrophil response to two chemotactic agents, and to correlate the observed neutrophil defects with the degree of diabetes. In this study two chemotactic agents, casein (0.2 μl, 2 mg ml−1) or N‐formylmethionylleucylphenylalanine (FMLP; 0.2 μl, 10−4 M), were placed into the gingival crevices of alloxan‐induced diabetic rats. Gingival biopsies were taken 15 min later and then at 5‐min intervals up to 45 min and investigated by electron microscopy. Adherence and migration were observed in the rats with moderate diabetes 30 min after the application of casein. There was chemotaxis after 35 min of administration of the peptide FMLP. By 40 min neutrophils with pyknotic nuclei were observed. At 45 min neutrophils with a decreased number of granules were present. As the severity of the diabetes increased, the neutrophils degenerated and were structurally distorted. In the rats which had alloxan‐induced diabetes there was abnormal periodontal damage. This damage is thought to be related to dysfunctional neutrophils. These findings many contribute to an answer to the following question: why is there an apparent variability in the susceptibilty of periodontal breakdown in diabetics? Copyright © 2003 John Wiley & Sons, Ltd.
Tyrosine aminotransferase and gamma‐glutamyl transferase activity in human fetal hepatocyte primary cultures under proliferative conditions
Authors: Rehman Khaja K. , Ayesha Qamar , Khan Aleem A. , Ahmed Niyaz , Habibullah Chittor M. 
Published: March 2004

AbstractThe ontogeny of gamma‐glutamyl transferase (GGTase; E.C.2.3.2.2) and tyrosine aminotransferase (TAT; E.C.2.6.1.5) activities in 14 to 36 weeks gestational and neonatal hepatocytes during development of human fetal liver was studied. Subsequently, 20–24 weeks gestational hepatocytes were cultured in media supplemented with epidermal growth factor (EGF) and insulin with or without glucagon and dexamethasone to investigate the proliferation and differentiation of fetal hepatocyte in vitro using GGTase and TAT as biochemical markers. During the development of the liver, the activity of GGTase increased continuously from the first trimester through the third trimester and decreased (p < 0.001) in neonates. A low basal level of TAT activity was seen only during the third trimester, which then increased significantly (p < 0.001) in neonates. Fetal hepatocytes, in the presence of EGF and insulin, undergo proliferation from the fourth to 10th day with an increase in cell number (p < 0.001) and concomitant increase (p < 0.001) in GGTase activity. As the cells attain confluence, enzyme activity decreased significantly (p < 0.001) from the 10th to 16th day. Maximal TAT activity (p < 0.001) was observed at 48 h of culture, which decreased, but not significantly, during cell proliferation and the enzyme activity was regained as the cultures attained confluence. Furthermore, TAT activity was induced synergistically (p<0.001) in the presence of glucagon and dexamethasone, while GGTase was inhibited (p<0.001). These results indicate that GGTase increases with proliferation, whereas TAT, once it has been expressed, is not suppressed during cell proliferation. In conclusion, human fetal hepatocytes undergo enzymic differentiation by 48 h of culture, and proliferate with an increase in GGTase in the presence of growth factors with maintenance of differentiated status up to the studied 16 days of culture. Copyright © 2003 John Wiley & Sons, Ltd.
Protective effect of glycine supplementation on the levels of lipid peroxidation and antioxidant enzymes in the erythrocyte of rats with alcohol‐induced liver injury
Authors: Senthilkumar R. , Sengottuvelan M. , Nalini N. 
Published: March 2004

AbstractWe studied the effect of glycine supplementation on lipid peroxidation and antioxidants in the erythrocyte membrane, plasma and hepatocytes of rats with alcohol‐induced hepatotoxicity. Administering ethanol (20%) for 60 days to male Wistar rats resulted in significantly elevated levels of erythrocyte membrane, plasma and hepatocyte thiobarbituric acid reactive substances (TBARS) as compared with those of the experimental control rats. Decreased activities of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx) and glutathione reductase (GR) were also observed on alcohol supplementation as compared with those of the experimental control rats. Glycine was administered at a dose of 0.6 g kg−1 body weight to rats with alcohol‐induced liver injury, which significantly decreased the levels of TBARS and significantly elevated the activities of SOD, CAT, GSH, GPx and GR in the erythrocyte membrane, plasma and hepatocytes as compared to that of untreated alcohol supplemented rats. Thus, our data indicate that supplementation with glycine offers protection against free radical‐mediated oxidative stress in the erythrocyte membrane, plasma and hepatocytes of animals with alcohol‐induced liver injury. Copyright © 2003 John Wiley & Sons, Ltd.
The protective effect of ursodeoxycholic acid in alloxan‐induced diabetes
Authors: Lukivskaya Oxana , Lis Ruslan , Egorov Alexander , Naruta Elena , Tauschel Horst‐Dietmar , Buko Vyacheslav U. 
Published: March 2004

AbstractThe purpose of this work was to study the effect of ursodeoxycholic acid (UDCA) on the morphological and functional alterations in pancreatic islet β‐cells in rats with diabetes induced by alloxan (150 mg kg−1, i.p.). UDCA (40 mg kg−1, i.g.) was administered daily from the fifth to the 35th day after the alloxan treatment. The treatment of diabetic rats with UDCA improved the pancreatic morphology disturbed by the alloxan treatment: UDCA increased the number of pancreatic islets and β‐cells, the β‐/α‐cell ratio and decreased the number of α‐cells. As the morphometric data suggest, the treatment of diabetic animals with UDCA significantly increased the area of β‐cell cytoplasmatic granules stained by paraldehyde–fuchsin. The concentration of blood glucose in diabetic rats was gradually decreased after the UDCA treatment, and at the end of the experiment reached the control value. The treatment with UDCA raised the serum insulin level in diabetic rats about 2.5‐fold, but this concentration was significantly lower as compared to the control group. The content of lipid peroxidation end‐products, hydroxyalkenals and malondialdehyde, was significantly elevated in the alloxan‐treated rats, whereas the treatment with UDCA normalized these parameters. The present data indicate that UDCA acts as an effective antidiabetic agent in alloxan‐induced diabetes and its beneficial effects in diabetic rats can be related to the antioxidant properties of UDCA. Copyright © 2003 John Wiley & Sons, Ltd.
Crystal Refinement and Magnetic Structure of KNi4(PO4)3: A Novel Example of Three Interacting Magnetic Sub‐Lattices
Authors: López María‐Luisa , Durio Cristina , Daidouh Abdelaali , Pico Carlos , Veiga María‐Luisa 
Published: March 2004

AbstractKNi4(PO4)3 has been synthesised following a method previously reported by some of us and studied on the basis of magnetization and neutron powder diffraction (NPD) data. Magnetization measurements suggest the coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) interactions: magnetization versus magnetic field curves present a remanent magnetization of around 2.15 μB at T=2 K. The magnetic structure of the KNi4(PO4)3 has been determined at low temperature from the NPD data. These measurements show that there are three magnetic sub‐lattices of Ni2+ ions, which interact through common oxygen or phosphate groups, giving rise to FM and AFM couplings. The resulting interactions are FM in nature. Such a complex behaviour could provide an interesting model to analyse magnetic interactions in more condensed systems, such in mixed metal oxides.
More Arrows in the Quiver: New Pathways and Old Problems with Heavy Alkaline Earth Metal Diphenylmethanides
Authors: Alexander Jacob S. , Ruhlandt‐Senge Karin 
Published: March 2004

AbstractProgress in the field of σ‐bonded alkaline earth organometallics has been handicapped by numerous complications, such as high reactivity, low solubility, and the limited availability of suitable starting materials. Here we present two synthetic methods, hydrocarbon elimination and desilylation, as alternative routes into this chemistry. A novel barium diphenylmethanide was prepared using these routes delineating that both methods provide a powerful, versatile synthetic access route to an extended library of organometallic alkaline earth derivatives.
A Surface‐Modified Dendrimer Set for Potential Application as Drug Delivery Vehicles: Synthesis, In Vitro Toxicity, and Intracellular Localization
Authors: Fuchs Sabine , Kapp Timo , Otto Henning , Schöneberg Torsten , Franke Peter , Gust Ronald , Schlüter A. Dieter 
Published: March 2004

AbstractThe synthesis, cytotoxicity, and behavior in cell culture of a new set of first‐ (G1) and second‐generation (G2) dendrimers is reported. The surface functionality of these dendrimers has been varied to see whether structure/toxicity relations can be observed. The outermost functional groups are amines that are decorated either with protons, tert‐butoxycarbonyl (Boc) or benzyloxycarbonyl (Cbz) protecting groups, Boc‐protected or unprotected natural amino acid residues, ethylenediamine ligands, and/or dansyl fluorescence labels. The cytotoxicity was determined in vitro in concentration‐dependent assays using the human MCF‐7 breast cancer cell line. Cellular uptake and intracellular distribution was monitored by confocal fluorescence microscopy after internalization of the dansyl‐labeled dendrimers by HeLa cells.
Solid‐Phase Synthesis of DOTA–Peptides
Authors: De León‐Rodriguez Luis M. , Kovacs Zoltan , Dieckmann Gregg R. , Sherry A. Dean 
Published: March 2004

AbstractA general synthetic route to two DOTA‐linked N‐Fmoc amino acids (DOTA‐F and DOTA‐K) is described that allows insertion of DOTA at any endo‐position within a peptide sequence. Three model pentapeptides were prepared to test the general utility of these derivatives in solid‐phase peptide synthesis. Both DOTA derivatives reacted smoothly by means of standard HBTU activation chemistry to the point of insertion of the DOTA amino acid, but extension of the peptide chain beyond the DOTA‐amino acid insertion required the use of pre‐activated C‐pentafluorophenyl ester N‐α‐Fmoc amino acids. Three Gal‐80 binding peptides (12‐mers) were then prepared by using this methodology with DOTA positioned either at the N terminus or at one of two different internal positions;the binding of the resulting GdDOTA‐12‐mers to Gal‐80 were compared. The methodology described here allows versatile, controlled introduction of DOTA into any location within a peptide sequence. This provides a potential method for the screening of libraries of DOTA‐linked peptides for optimal targeting properties.
Steric and Electronic Effects in Cyclic Alkoxyamines—Synthesis and Applications as Regulators for Controlled/Living Radical Polymerization
Authors: Wetter Christian , Gierlich Johannes , Knoop Christoph Alexander , Müller Christoph , Schulte Tobias , Studer Armido 
Published: March 2004

AbstractThe synthesis of new six‐ and seven‐membered cyclic alkoxyamines bearing ethyl groups at the α‐N position of the alkoxyamines is described. The key step in the synthesis of the sterically hindered six‐membered cyclic alkoxyamines is a Wadsworth–Horner–Emmons olefination with bisphosphonate 1. The seven‐membered cyclic alkoxyamines were prepared from the corresponding six‐membered keto alkoxyamines by ring‐enlargement with trimethylsilyl(TMS)‐diazomethane. The use of the new alkoxyamines as regulators/initiators for radical polymerization is discussed. Efficient controlled and living polymerization of styrene and n‐butyl acrylate was obtained with the six‐membered tetraethyl alkoxyamine 13. Controlled polymerizations can be conducted even at 90 °C. In addition, alkoxyamine 13 can be used for the preparation of AB diblock and ABA triblock copolymers with narrow polydispersities. The influence of the replacement of methyl groups in the α‐position of the N atom in cyclic alkoxyamines by larger ethyl groups on the styrene polymerization (reaction time, PDI, kinetics of the CO bond homolysis) is discussed. In addition, thermal decomposition of the new alkoxyamines was studied. Furthermore, the synthesis of N,N‐bissilylated alkoxyamines is described. The silylated alkoxyamines are not suitable as regulators/initiators for the controlled/living radical polymerization. The CO bonds in silylated alkoxyamines are stronger than the CO bonds in analogous N,N‐dialkylated alkoxyamines. The experimental results are verified by calculations with Gaussian 98 (A. 9).
Functionalization of Octavinylsilsesquioxane by Ruthenium‐Catalyzed Silylative Coupling versus Cross‐Metathesis
Authors: Itami Y. , Marciniec B. , Kubicki M. 
Published: March 2004

AbstractFunctionalization of octavinylsilsesquioxane (Vi8T8, 1) by two reactions catalyzed by ruthenium complexes is reported: a silylative coupling reaction catalyzed by [RuHCl(CO)(PCy3)2] (I) and cross‐metathesis catalyzed by first‐ (II) and second‐generation (III) Grubbs’ catalysts. The two reactions of 1 with styrene take place highly regio‐ and stereoselectively (the X‐ray structure of the product 2 has also been obtained); the cross‐metathesis of 1‐hexene and allyltrimethylsilane occurs quite effectively, whereas the silylative coupling with these compounds gives a mixture of isomers. Functionalization of 1 with heteroatom‐substituted vinyl derivatives (Si, O, N) by silylative coupling reaction has been found to be highly efficient, but cross‐metathesis appears to be the more effective method for the synthesis of S‐substituted vinyl‐silsesquioxane.