bluuebunny/crossref_metadata_2025 huggingface dataset:
On‐line adaptive trend extraction of multiple physiological signals for alarm filtering in intensive care units
Authors: Charbonnier S. , Gentil S.
Published: June 2009

This paper presents an alarm validation system dedicated to patient monitoring in intensive care units (ICU). Several physiological signals are continuously acquired and an on‐line trend extraction method is implemented for each one. A trend is a succession of contiguous semi‐quantitative episodes, expressing the time evolution of a signal with several symbols. The difference between the trend and the signal is considered as a residual. In this paper, trend extraction is based on several thresholds that are adapted on‐line, following the signal variations. Multivariate change indices are further deduced from the trends and the residuals. They provide an indication of changes to patient hemodynamic and respiratory state. An alarm validation system based on these indices is then proposed, which uses fuzzy decision making. Whenever a monitoring system sets off an alarm, the system proposed carries out a backward analysis of the physiological variables monitored. The system enables various policies to be implemented: filtering of false alarms due to artifacts, confirmation of true alarms due to a patient state change. The system was tested on more than 50 h of data recorded on adult patients in an ICU unit, when 105SpO2alarms were set off by a fixed threshold alarm system. The comparison between the decision made on‐line by the validation system and the decision made by a medical expert for each of these alarms showed that the system is able to recognize 100% of true alarms and filter 50–80% of false alarms. Copyright © 2009 John Wiley & Sons, Ltd.
Discrete‐time Lyapunov stable‐staggered estimator MIMO adaptive interference cancelation with experimental verification
Authors: Arif Jawad , Akhtar Suhail
Published: June 2009

Adaptive interference cancelation is of vital importance in a broad array of scientific and engineering disciplines. In this paper we develop a closed‐loop discrete‐time interference cancelation algorithm. The novel features of this algorithm are its ability to deal with multiple channels being affected by interferences with different frequency spectrums. Also we provide a proof of Lyapunov stability of closed‐loop system and asymptotically perfect interference cancelation for a class of interference signals. Furthermore, we introduce a new approach for updating the estimator through the use of staggered estimate. The goal of staggered estimation is to minimize the total number of estimates/calculations done within a time period while ensuring that there is no estimator aliasing. Finally, the proposed algorithm is implemented on an TMS320C6713 DSP Kit and an experimental verification is obtained. Copyright © 2009 John Wiley & Sons, Ltd.
Recyclable Polymer‐ and Silica‐Supported Ruthenium(II)‐Salen Bis‐pyridine Catalysts for the Asymmetric Cyclopropanation of Olefins
Authors: Gill Christopher S. , Venkatasubbaiah Krishnan , Jones Christopher W.
Published: June 2009

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Homogeneous ruthenium(II)‐salen bis‐pyridine complexes are known to be highly active and selective catalysts for the asymmetric cyclopropanation of terminal olefins. Here, new methods of heterogenization of these Ru‐salen catalysts on polymer and porous silica supports are demonstrated for the facile recovery and recycle of these expensive catalysts. Activities, selectivities, and recyclabilities are investigated and compared to the analogous homogeneous and other supported catalysts for asymmetric cyclopropanation reactions. The catalysts are characterized with a variety of methods including solid state cross‐polarization magic‐angle spinning (CP MAS) 13C and 29Si NMR, FT‐IR, elemental analysis, and thermogravimetric analysis. Initial investigations produced catalysts possessing high selectivities but decreasing activities upon reuse. Addition of excess pyridine during the washing steps between cycles was observed to maintain high catalytic activities over multiple cycles with no impact on selectivity. Polymer‐supported catalysts showed superior activity and selectivity compared to the porous silica‐supported catalyst. Additionally, a longer, flexible linker between the Ru‐salen catalyst and support was observed to increase enantioselectivity and diastereoselectivity, but had no effect on activity of the resin catalysts. Furthermore, the polymer‐supported Ru‐salen‐Py2 catalysts were found to generate superior selectivities and yields compared to other leading heterogeneous asymmetric cyclopropanation catalysts.
A Three‐Dimensional Quanititative Structure‐Activity Relationship (3D‐QSAR) Model for Predicting the Enantioselectivity of Candida antarctica Lipase B
Authors: Braiuca Paolo , Lorena Knapic , Ferrario Valerio , Ebert Cynthia , Gardossi Lucia
Published: June 2009

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Computational techniques involving molecular modeling coupled with multivariate statistical analysis were used to evaluate and predict quantitatively the enantioselectivity of lipase B from Candida antarctica (CALB). In order to allow the mathematical and statistical processing of the experimental data largely available in the literature (namely enantiomeric ratio E), a novel class of GRID‐based molecular descriptors was developed (differential molecular interaction fields or DMIFs). These descriptors proved to be efficient in providing the structural information needed for computing the regression model. Multivariate statistical methods based on PLS (partial least square – projection to latent structures), were used for the analysis of data available from the literature and for the construction of the first three‐dimensional quanititative structure‐activity relationship (3D‐QSAR) model able to predict the enantioselectivity of CALB. Our results indicate that the model is statistically robust and predictive.
Effective Chiral Ferrocenyl Phosphine‐Thioether Ligands in Enantioselective Palladium‐Catalyzed Allylic Alkylations
Authors: Cheung Hong Yee , Yu Wing‐Yiu , Au‐Yeung Terry T. L. , Zhou Zhongyuan , Chan Albert S. C.
Published: June 2009

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Chiral ferrocene‐derived phosphine‐thioether mixed donor ligands supported by heterocycles effected the palladium‐catalyzed enantioselective allylic alkylations with excellent yields and enantioselectivities (up to 96% ee). With cyclic and unsymmetrical allylic acetates as substrate, the corresponding alkylated products with enantioselectivities up to 87% ee were obtained. Based on X‐ray crystallographic and NMR studies, the origin of the observed enantioselectivities is discussed.
Improved Protocols for Molybdenum‐ und Tungsten‐Catalyzed Hydrostannations
Authors: Wesquet Alexander O. , Kazmaier Uli
Published: June 2009

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A series of (isonitrile)tungsten carbonyl complexes of type W(CO)m(CNR)n has been synthesized and evaluated as hydrostannation catalysts. The results are compared with those obtained by the previously reported tri(tert‐butylisonitrile)molybdenum tricarbonyl catalyst, Mo(CO)3(CN‐t‐Bu)3 (=MoBI3). The yields and selectivities strongly depend on the isonitriles used, and with certain substrates better results are obtained compared to the molybdenum catalyst. No side products are observed in hydrostannations under microwave irradiation or when the reactions are carried out under an atmosphere of carbon monoxide. Based on these findings, a mechanistic rational is given, explaining the different pathways responsible for the formation of hydrostannation or distannation products.
Catalytic Asymmetric Cycloaddition of Carbon Dioxide and Propylene Oxide Using Novel Chiral Polymers of BINOL‐Salen‐ Cobalt(III) Salts
Authors: Yan Peng , Jing Huanwang
Published: June 2009

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Four new chiral polymers of BINOL‐Salen‐cobalt(III) salt complexes have been designed, synthesized and applied to the direct fabrication of chiral propylene carbonate from racemic propylene oxide. The (R/S)‐polymer catalyst 2 and (S/R)‐polymer catalyst 4 exhibit better enantioselectivity than the (R/R)‐polymer catalyst 1 and the (S/S)‐polymer catalyst 3 and have been recovered and reused more than ten times without loss of activity and enantioselectivity.
Grooming in mandrills and the time frame of reciprocal partner choice
Authors: Schino Gabriele , Pellegrini Barbara
Published: June 2009

In this study, we examined the time frame of reciprocal partner choice in the grooming interactions of captive mandrills (Mandrillus sphinx) in order to test the hypothesis that the cognitive limitations of primates constrain the occurrence of reciprocation to short time intervals. In contrast to this hypothesis, mandrills groomed preferentially those individuals that groomed them more even when cases of immediate reciprocation were excluded from the analysis. These results show that mandrills were not limited to reciprocating grooming over short time intervals. It is proposed that a system of emotional bookkeeping may support the ability of primates to reciprocate over long time frames. Am. J. Primatol. 71:884–888, 2009. © 2009 Wiley‐Liss, Inc.
What corporations need to know about how to install an integrated conflict management system
Authors: Katz Deborah A. , Cohen Judith
Published: June 2009

In the second of two parts, Deborah A. Katz, of the U.S. Transportation Security Administration, discusses how the agency's recent conflict management system development encourages better communication and operations. The focus this month is on adapting the system to other business settings. She is interviewed by New York conflict resolution consultant Judith Cohen.
Strukturbasis und Enzymmechanismus der Biosynthese von C9‐ aus C10‐monoterpenoiden Indol‐Alkaloiden
Authors: Yang Liuqing , Hill Marco , Wang Meitian , Panjikar Santosh , Stöckigt Joachim
Published: June 2009

Alle Neune: Die dreidimensionale Struktur der Polyneuridinaldehyd‐Esterase (PNAE) gibt einen Einblick in den Enzymmechanismus der Biosynthese von C9‐ aus C10‐monoterpenoiden Indol‐Alkaloiden (siehe Schema). PNAE ist eine sehr substratspezifische Serin‐Esterase. Sie enthält die katalytische Triade S87‐D216‐H244 und ist ein neues Mitglied der Superfamilie der α/β‐Hydrolasen, allerdings mit einer neuartigen Funktion: der Diversifizierung von Alkaloidstrukturen.

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An [(NHC)(NHCEWG)RuCl2(CHPh)] Complex for the Efficient Formation of Sterically Hindered Olefins by Ring‐Closing Metathesis
Authors: Vorfalt Tim , Leuthäußer Steffen , Plenio Herbert
Published: June 2009

Ein NHC mit EWGs für die RCM: Ein Rutheniumkomplex mit zwei unterschiedlichen N‐heterocyclischen Carbenliganden (NHCs), von denen einer mit elektronenziehenden Gruppen (EWGs) substituiert ist, ist ein hoch effizienter (Prä‐)Katalysator für die Synthese tri‐ und tetrasubstituierter Olefine durch Ringschlussmetathese (RCM; siehe Schema).

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Liquid‐Crystalline Phases Made of Gold Nanoparticles
Authors: Wojcik Michal , Lewandowski Wiktor , Matraszek Joanna , Mieczkowski Jozef , Borysiuk Jolanta , Pociecha Damian , Gorecka Ewa
Published: June 2009

Die spontane Bildung von smektischen und kolumnaren Strukturen wurde beobachtet, wenn sphärische Goldnanopartikel mit mesogenen Thiolen funktionalisiert wurden (siehe Schichtstruktur und Röntgenbeugungsmuster einer Probe mit smektischer Phase). Die Verringerung des Interpartikelpotentials und die Flexibilität der Pfropfschicht sind für die strukturierte Anordnung der Partikel entscheidend.

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Microemulsions.Background, New Concepts, Applications, Perspectives. Herausgegeben von Cosima Stubenrauch.
Authors: Walsh Dominic
Published: June 2009

John Wiley & Sons, Hoboken 2008. 400 S., geb., 129.00 €.—ISBN 978‐1405167826

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A Synthesis of an Ionomycin Calcium Complex
Authors: Gao Zhanghua , Li Yingfa , Cooksey John P. , Snaddon Thomas N. , Schunk Stefan , Viseux Eddy M. E. , McAteer Stephen M. , Kocienski Philip J.
Published: June 2009

Mit Kupfer, Gold und Rhodium zum Calciumkomplex von Ionomycin (siehe Struktur; O rot, Ca grün): Dafür wurde die effiziente Synthese eines Allens durch eine CuI‐vermittelte anti‐selektive SN2′‐Reaktion mit einer hoch stereoselektiven AuIII‐katalysierten Cycloisomerisierung eines α‐Hydroxyallens und einer Rh‐katalysierten Umlagerung eines α‐Diazo‐β‐hydroxyketons kombiniert.

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Titelbild: Toroidal Micelles of Uniform Size from Diblock Copolymers (Angew. Chem. 25/2009)
Authors: Huang Haiying , Chung Bonghoon , Jung Jueun , Park Hae‐Woong , Chang Taihyun
Published: June 2009

Rein toroidale Micellen mit sehr einheitlicher Form und Größe stellen T. Chang et al. in der Zuschrift auf S. 4664 ff. vor. Die Donut‐förmigen Micellen entstehen durch spontane Selbstorganisation eines Polyisopren‐block‐poly(2‐vinylpyridin)‐Copolymers und sind stabil genug, um als Templat für das Wachsen von Goldnanopartikeln entlang der Ringoberfläche zu dienen.

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Innentitelbild: Multicompartmental Microcylinders (Angew. Chem. 25/2009)
Authors: Bhaskar Srijanani , Hitt Jonathon , Chang Sei‐Won Laura , Lahann Joerg
Published: June 2009

Mikrozylinder mit mehreren Kompartimenten lassen sich mit einer Kombination aus elektrohydrodynamischem Spinnen und Mikroabtrennen herstellen, wie J. Lahann et al. in der Zuschrift auf S. 4659 ff. beschreiben. Die Zahl der einzelnen Kompartimente, ihre relative Orientierung, chemische Zusammensetzung und Funktionalität sowie das Seitenverhältnis können maßgeschneidert eingestellt werden. Jede Farbe in den Längs‐ und Querschnitt‐Mikrographen entspricht einem individuellen Kompartiment.

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Liquid‐Crystalline Phases Made of Gold Nanoparticles
Authors: Wojcik Michal , Lewandowski Wiktor , Matraszek Joanna , Mieczkowski Jozef , Borysiuk Jolanta , Pociecha Damian , Gorecka Ewa
Published: June 2009

Spontaneous formation of smectic and columnar structures was observed when spherical gold nanoparticles were functionalized with mesogenic thiols (see layered structure and X‐ray pattern of a sample in smectic phase). The particle ordering is stimulated by softening of the interparticle potential and flexibility for deformation of the grafting layer.

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A Synthesis of an Ionomycin Calcium Complex
Authors: Gao Zhanghua , Li Yingfa , Cooksey John P. , Snaddon Thomas N. , Schunk Stefan , Viseux Eddy M. E. , McAteer Stephen M. , Kocienski Philip J.
Published: June 2009

Caught in the middle: The ionomycin calcium complex (see structure; O red, Ca green) was the target of an approach featuring the efficient asymmetric synthesis of an allene by a copper(I)‐mediated anti‐selective SN2′ reaction, a highly stereoselective gold(III)‐catalyzed cycloisomerization of an α‐hydroxyallene, and a Rh‐catalyzed rearrangement of an α‐diazo‐β‐hydroxyketone.

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Hydrogen Evolution at Liquid–Liquid Interfaces
Authors: Hatay Imren , Su Bin , Li Fei , Partovi‐Nia Raheleh , Vrubel Heron , Hu Xile , Ersoz Mustafa , Girault Hubert H.
Published: June 2009

Blowing bubbles: Hydrogen evolution by proton reduction with [(C5Me5)2Fe] occurs at a soft interface between water and 1,2‐dichloroethane (DCE). The reaction proceeds by proton transfer assisted by [(C5Me5)2Fe] across the water–DCE interface with subsequent proton reduction in DCE. The interface essentially acts as a proton pump, allowing hydrogen evolution by directly using the aqueous proton.

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Impact of impregnation with boron compounds on the surface hardness and abrasion resistance of some varnished woods
Authors: Atar Musa , Uysal Burhanettin , Saríca Mutlu
Published: June 2009

This study was performed to determine the impact of impregnation with boron compounds on the surface hardness and abrasion resistance of some varnished woods. For this purpose, test specimens prepared from Oriental beech, White oak, Scotch pine, and Uludag fir, which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413‐99 with boric acid (Ba), borax (Bx), and boric acid + borax (Ba+Bx) by the vacuum technique. After impregnation, the surfaces are coated with synthetic (Sn), water‐borne (Wb) and acid hardening (Ah) varnishes in accordance with ASTM D 3023. the surface hardness of specimens after the varnishing process was determined in accordance with ASTM D 4366. The abrasion resistance of specimens after the varnishing process was determined in accordance with TS 4755. According to the wood type, impregnation material and varnish type, the surface hardness was the highest for Oriental beech impregnated with borax + boric acid and acid hardening varnish and the lowest for Uludag fir impregnated with borax + boric acid and synthetic varnish. According to the wood type, impregnation material and varnish type, the abrasion resistance was the highest for Oriental beech impregnated with borax + boric acid and acid hardening varnish and the lowest for Scotch pine impregnated with borax + boric acid and synthetic varnish. Those results should be taken into account for applications like parquet, flooring etc., where the surface hardness and abrasion resistance values are very important. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Investigation of electrical conduction mechanism in double‐layered polymeric system
Authors: Shukla Prashant , Gaur M. S.
Published: June 2009

The electrical conduction in solution‐grown polymethylmethacrylate (PMMA), polyvinylidenefluoride (PVDF) and PMMA‐PVDF double‐layered samples in the sandwich configuration (metal‐polymer‐metal) was investigated at different fields in the range 100–120 kV/cm as a function of temperature in the range 293–423 K for samples of constant thickness of about 50 μm. Certain effects which lead to a large burst of current immediately after the application of field were observed in double‐layered samples. An attempt was made to identify the nature of the current by comparing the observed dependence on electric field, electrode material and temperature with the respective characteristic features of the existing theories on electrical conduction. The observed linear I‐V characteristics show that the electrical conduction follows Pool‐Frenkel mechanism in PMMA and PVDF samples. Whereas, the non‐linear behavior of current‐voltage measurements in PMMA‐PVDF double‐layered samples have been interpreted on the basis of space charge limited conduction (SCLC) mechanism. The conductivity of the polymer films increased on formation of their double‐layer laminates. The polymer‐polymer interface act as charge carrier trapping centres and provides links between the polymer molecules in the amorphous region. The interfacial phenomenon in polymer‐polymer heterogeneous system has been interpreted in terms of Maxwell‐Wagner model. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cellulose–chitosan interpenetrating polymer network for electro‐active paper actuator
Authors: Cai Zhijiang , Kim Jaehwan
Published: June 2009

In this article, the cellulose‐chitosan interpenetrating polymer network (IPN) films were prepared and fabricated as the electro‐active paper actuator. The characteristics of the cellulose–chitosan IPN films were examined by SEM, FT‐IR, XRD, DSC, and tensile test. The performance of the IPNs based actuator was evaluated in terms of bending displacement with respect to the actuation frequency, voltages, humidity levels, chitosan content, and time variation. It was observed that with chitosan content increasing in the IPNs, the crystallinity decreased and the network became denser, which caused the Young's modulus to increase. Chitosan content in IPNs also significantly affected the bending performance. The optimum IPN weight ratio of cellulose and chitosan was 60 : 40. The maximum bending displacement of 7.2 mm was found at 80% relative humidity level. In terms of durability, the bending lifetime at 70% humidity level was about 10 h with 17% performance degradation. More issues on the actuator performance and durability are addressed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of higher soluble nanostructured polyaniline by vapor‐phase polymerization and determination of its crystal structure
Authors: Bhadra Sambhu , Lee Joong Hee
Published: June 2009

Higher soluble nanostructured polyaniline was prepared by vapor‐phase polymerization after passing aniline vapor through an aqueous acidic solution of ammonium persulfate (PANI‐V). Polyaniline was also synthesized by the conventional oxidative polymerization method (PANI‐C) in an aqueous medium for the comparison of its properties with PANI‐V. PANI‐V exhibited lower conductivity but higher hydrophilicity and higher solubility (2–3 times) in different solvents, such as tetrahydrofuran, N‐methyl‐2‐pyrrolidone, dimethylsulfoxide, N,N‐dimethyl formamide, and m‐cresol at room temperature compared with that of PANI‐C. The thermal stability of PANI‐V was higher than that of PANI‐C. In‐depth investigations of the crystal structures of PANI‐C and PANI‐V were performed through powder X‐ray diffraction analysis. The PANI‐V showed a less ordered structure with a lower crystallinity and crystallite size and with a higher d‐spacing and interchain separation compared with PANI‐C. The unit cell volume of PANI‐V was significantly higher with a greater number of atoms in the unit cell than that of PANI‐C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and properties of biocomposites based on jute fibers and blend of plasticized starch and poly(β‐hydroxybutyrate)
Authors: Belhassen Ramzi , Méndez José Alberto , Boufi Sami , López Joan Pere , Puig Josep , Pèlach Angels , Mutjé Pere
Published: June 2009

In this work, preparation and properties of biocomposites based on jute fibers and blend of plasticized starch and poly(β‐hydroxybutyrate) (PHB) have been investigated. Different amounts of glycerol and aliphatic polyesters (PHB) have been added to native starch to obtain a processable biodegradable matrix. In the same way natural jute fibers up to 30 wt % loading were added to improve the mechanical and thermal stability of the material. Tensile mechanical, thermal, and thermomecahnical analyses have been performed to characterize the ensuing materials. Significant enhancement in the mechanical properties and water sensitivity were noted by the addition of 8 wt % PHB. The fibers incorporation into the biopolymer matrix brings about an increase in both the mechanical strength and modulus as much higher as the fibers loading is important. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Cloning and expression of the gene for an insect haemocyte anti‐aggregation protein (VPr3), from the venom of the endoparasitic wasp, Pimpla hypochondriaca
Authors: Dani M. Paulina , Richards Elaine H.
Published: June 2009

A venom protein from the endoparasitic wasp, Pimpla hypochondriaca, was recently biochemically isolated. This protein possessed haemocyte anti‐aggregation activity in vitro and shares the same N‐terminal amino acid sequence as that deduced from a gene termed vpr3. The vpr3 gene was identified by sequence analysis of randomly isolated cDNAs from a P. hypochondriaca venom gland library. Presently, the gene for the full‐length sequence of mature VPr3 protein was amplified from the P. hypochondriaca venom gland cDNA library by PCR. The amplicon was directionally cloned into a pET expression vector so that recombinant VPr3 (rVPr3) would have an N‐terminal polyhistidine (His) tag. High levels of target protein expression were obtained following addition of IPTG (1 mM) and growth of the bacteria at 37°C for 5 h, or at 24°C for 20 h. Following lysis of bacteria grown at 37°C, the target protein partitioned into the insoluble fraction. However, at 24°C, a small amount of soluble protein was consistently detected. The amount of soluble rVPr3 was subsequently increased when the transformed bacteria were grown in Overnight Express Instant TB medium at 24°C. Soluble rVPr3 was purified utilizing the MagneHis Protein Purification System. Recombinant VPr3 was determined to have adverse effects on the cytoskeleton of Lacanobia oleracea haemocytes and to inhibit the ability of these cells to form aggregates in vitro. © 2009 Wiley Periodicals, Inc.
Managing polysemy and synonymy in science mapping using the mixtures of factor analyzers model
Authors: Kwakkel Jan H. , Cunningham Scott W.
Published: June 2009

A new method for mapping the semantic structure of science is described. We assume that different researchers, working on the same set of research problems, will use the same words for concepts central to their research problems. Therefore, different research fields and disciplines should be identifiable by different words and the pattern of co‐occurring words. In natural language, however, there is quite some diversity because many words have multiple meaning. In addition, the same meaning can be expressed by using different words. We argue that traditional factor analytic and cluster analytic techniques are inadequate for mapping the semantic structure if such polysemous and synonymous words are present. Instead, an alternative model, the mixtures of factor analyzers (MFA) model, is utilized. This model extends the traditional factor analytic model by allowing multiple centroids of the dataset. We argue that this model is structurally better suited to map the semantic structure of science. The model is illustrated by a case study of the uncertainty literature sampled from data from the ISI Web of Science. The MFA model is applied with the goal of discovering multiple, potentially incommensurate, conceptualizations of uncertainty in the literature. In this way, the MFA model can help in creating understanding of the use of language in science, which can benefit multidisciplinary research and interdisciplinary understanding, and assist in the development of multidisciplinary taxonomies of science.
Measuring consistency for multiple taggers using vector space modeling
Authors: Wolfram Dietmar , Olson Hope A. , Bloom Raina
Published: June 2009

A longstanding area of study in indexing is the identification of factors affecting vocabulary usage and consistency. This topic has seen a recent resurgence with a focus on social tagging. Tagging data for scholarly articles made available by the social bookmarking Website CiteULike (www.citeulike.org) were used to test the use of inter‐indexer/tagger consistency density values, based on a method developed by the authors by comparing calculations for highly tagged documents representing three subject areas (Science, Social Science, Social Software). The analysis revealed that the developed method is viable for a large dataset. The findings also indicated that there were no significant differences in tagging consistency among the three topic areas, demonstrating that vocabulary usage in a relatively new subject area like social software is no more inconsistent than the more established subject areas investigated. The implications of the method used and the findings are discussed.
Topological entropy and data rate for practical stability: a scalar case
Authors: Xie Li
Published: June 2009

A special class of nonlinear systems,i.e.expanding piecewise affine discrete‐time scalar systems with limited data rate, is used to investigate the role of topological entropy and date rate in a practical stability problem. This special class of nonlinear system as an abstract model is an extension of discrete‐time unstable scalar systems, a well‐known model for quantized feedback design. For such systems with finite quantization levels, how to design a quantized feedback controller to achieve practical stability is considered as a boundability problem. Unlike the existing results about topological entropy for nonlinear stabilization and optimal control for linear systems, for the boundability problem under consideration, the feedback topological entropy defined in this paper is not equal to the minimum number of the quantization interval (i.e.the minimal information rate) and only provides a necessary condition for the boundability of our system under some condition. A necessary and sufficient condition for the boundability is also presented in terms of an inequality related to data rate and the minimum number of quantization intervals. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A new delay‐dependent stability criterion for time‐delay systems
Authors: Sun Jian , Liu G. P.
Published: June 2009

This paper is concerned with the problem of stability of time‐delay systems. A new type of augmented Lyapunov functional is proposed. By introducing some free‐weighting matrices and using the parameterized model transformation method, a new delay‐dependent stability condition is obtained in terms of a linear matrix inequality (LMI). Numerical examples are given to illustrate the effectiveness of the proposed methods. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Global sliding‐mode control with generalized sliding dynamics
Authors: Lu Yu‐Sheng , Chiu Chien‐Wei
Published: June 2009

A global sliding‐mode control (GSMC) scheme is proposed to provide a framework for ensuring the existence of a sliding mode throughout an entire response. Based on this framework, robust eigenvalue‐assignment GSMC (REA‐GSMC) is proposed to robustly assign closed‐loop eigenvalues that must be real. The eigenvalues being all real, however, leads to sluggish responses. According to most error criteria such as IAE, ISE, and ITAE, the optimum system should have complex eigenvalues. This paper proposes a GSMC scheme with generalized sliding dynamics, referred to as Generalized GSMC, in order to release the previous constraint on the REA‐GSMC. Thus, the Generalized GSMC can be designed to achieve a system that is both robust and optimum in the sense that it minimizes certain error performance indices in spite of the presence of system uncertainties. Experiments were conducted on a two‐link direct‐drive manipulator to demonstrate the effectiveness of the proposed scheme. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
The impact of human superoxide dismutase 1 expression in a mouse model on the embryotoxicity of hydroxyurea
Authors: Larouche Geneviève , Hales Barbara F.
Published: June 2009

BACKGROUND:

Oxidative stress is hypothesized to mediate embryotoxicity during organogenesis, yet the reactive oxygen species involved are not defined. The superoxide oxygen radical is converted to hydrogen peroxide, a less reactive species, by superoxide dismutases (SODs). If superoxide is important in mediating embryotoxicity, increased SOD expression should protect embryos against insult. Exposure to hydroxyurea during organogenesis causes brain defects, cleft palate, tail anomalies, and limb defects; administration of D‐mannitol, a free radical scavenger, ameliorates hydroxyurea embryotoxicity, suggesting that oxidative stress is important. To elucidate the role of superoxide in mediating hydroxyurea embryotoxicity, we assessed the impact of human SOD1 expression in a murine model.

METHODS:

hSOD1 hemizygous male mice, carrying the human SOD1 gene, were mated to wild‐type or hSOD1 hemizygous females. Dams were treated on gestation day (GD) 9 with saline (control) or 400 (low) or 600 (high) mg/kg hydroxyurea (n = 8–13/group). Mice were euthanized on GD 18 and developmental toxicity was assessed.

RESULTS:

Exposure to hydroxyurea caused a dose‐dependent increase in fetal deaths that was not affected by hSOD1 expression; hydroxyurea decreased fetal weights in litters from wild‐type but not hemizygous dams. Hydroxyurea increased the incidence of external and skeletal malformations; fetuses from hemizygous dams treated with high‐dose hydroxyurea had fewer malformations compared to wild‐type dams. There was no correlation between embryonic phenotype and genotype or SOD activity.

CONCLUSION:

Maternal hSOD1 expression protected fetuses against malformations induced by hydroxyurea, providing evidence that superoxide plays a role in mediating the response of organogenesis stage embryos to this teratogen. Birth Defects Research (Part A) 2009. © 2009 Wiley‐Liss, Inc.
Lack of chick embryotoxicity after 20 kHz, 1.1 mT magnetic field exposure
Authors: Nishimura Izumi , Imai Setsuo , Negishi Tadashi
Published: June 2009

This investigation was undertaken because biological studies to evaluate the effects of intermediate frequency magnetic fields are insufficient. White Leghorn fertile eggs (60/group) were either exposed to a 20 kHz, 1.1 mT(rms) sinusoidal magnetic field or sham‐exposed during the first 2, 7, or 11 days of embryogenesis. Lower dose exposures at 0.011 and 0.11 mT(rms) for 2 days were also conducted to elucidate possible dose–response relationships. Additional eggs given all‐trans‐retinoic acid, a teratogen, were exposed to the 1.1 mT(rms) magnetic field for the same periods to investigate the modification of embryotoxicity. After exposure, embryos were examined for mortality and developmental abnormalities. Developmental stage, number of somite pairs, and other developmental endpoints were also evaluated. Experiments were triplicated and conducted in a blind fashion. No exposure‐related changes were found in any of the endpoints in intact embryos exposed to1.1 mT(rms) or to the lower doses of 0.11 and 0.011 mT(rms) magnetic fields. Retinoic acid administration produced embryotoxic responses, which were embryonic death and developmental abnormalities, in 40–60% of embryos in the sham‐exposed groups. The magnitude of these responses was not changed significantly by the magnetic field exposures. Under the present experimental conditions, exposure to 20 kHz magnetic field up to 1.1 mT(rms) was not embryotoxic in the chick and did not potentiate the embryotoxic action of retinoic acid. Bioelectromagnetics 30:573–582, 2009. © 2009 Wiley‐Liss, Inc.
A comprehensive kinetic model of laccase‐catalyzed oxidation of aqueous phenol
Authors: Kurniawati Selvia , Nicell James A.
Published: June 2009

A comprehensive model was developed to describe the kinetics of the laccase‐catalyzed oxidation of phenol that incorporates enzyme kinetics, enzyme inactivation, variable reaction stoichiometry between substrate and oxygen, and oxygen mass‐transfer. The model was calibrated and validated against data obtained from experiments conducted in an open system, which allowed oxygen to transfer from air to the reacting mixture and phenol conversion to approach completion. Inactivation of laccase was observed over the course of the reaction and was found to be dependent on the rate of substrate transformation. A single kinetic expression was sufficient to describe laccase inactivation arising from interaction with reacting species over time. Excellent agreement was found between model predictions of phenol and oxygen concentrations and experimental data over time for a wide range of initial substrate concentrations and enzyme activities. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Assessment of physiological conditions in E. coli fermentations by epifluorescent microscopy and image analysis
Authors: Carneiro Sónia , Amaral António L. , Veloso Ana C. A. , Dias Teresa , Peres António M. , Ferreira Eugénio C. , Rocha Isabel
Published: June 2009

The development of monitoring methods for assessing the physiological state of microorganisms during recombinant fermentation processes has been encouraged by the need to evaluate the influence of processing conditions in recombinant protein production. In this work, a technique based on microscopy and image analysis was developed that allows the simultaneous quantification of parameters associated with viability and fluorescent protein production in recombinant Escherichia coli fermentations. Images obtained from light microscopy with phase contrast are used to assess the total number of cells in a given sample and, from epifluorescence microscopy, both protein producing and injured cells are evaluated using two different fluorochromes: propidium iodide and enhanced yellow fluorescent protein. This technique revealed the existence of different cell populations in the recombinant E. coli fermentation broth that were evaluated along four batch fermentations, complementing information obtained with standard techniques to study the effects of the temperature and induction time in recombinant protein production processes. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Reduced modeling and state observation of an activated sludge process
Authors: Queinnec Isabelle , Gómez‐Quintero Claudia‐Sophya
Published: June 2009

This article first proposes a reduction strategy of the activated sludge process model with alternated aeration. Initiated with the standard activated sludge model (ASM1), the reduction is based on some biochemical considerations followed by linear approximations of nonlinear terms. Two submodels are then obtained, one for the aerobic phase and one for the anoxic phase, using four state variables related to the organic substrate concentration, the ammonium and nitrate‐nitrite nitrogen, and the oxygen concentration. Then, a two‐step robust estimation strategy is used to estimate both the unmeasured state variables and the unknown inflow ammonium nitrogen concentration. Parameter uncertainty is considered in the dynamics and input matrices of the system. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Resolution of (±)‐β‐methylphenylethylamine by a novel chiral stationary phase for Pirkle‐type column chromatography
Authors: Yilmaz Hayrullah , Topal Giray , Cakmak Resit , Hosgoren Halil
Published: June 2009

In this study, a new Pirkle‐type chiral column stationary phase for resolution of β‐methylphenylethyl amine was described by using activated Sepharose 4B as a matrix, L‐tyrosine as a spacer arm, and an aromatic amine derivative of L‐glutamic acid as a ligand. The binding capacities of the stationary phase were determined at different pH values (pH = 6, 7, and 8) using buffer solutions as mobile phase, and enantiomeric excess (ee) was determined by HPLC equipped with chiral column. The ee was found to be 47%. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Stereoselective effect of kynurenine enantiomers on the excretion of serotonin and its metabolite in rat urine
Authors: Sasaki Tsukasa , Fukushima Takeshi , Yamashita Kazuhide , Toyo'oka Toshimasa
Published: June 2009

A solution of optically pure kynurenine (KYN), i.e., D‐KYN or L‐KYN, was administered intravenously to male Sprague‐Dawley rats (10 mg kg−1 ml−1). The time‐course of changes in the concentrations of urinary monoamines and their metabolites such as 5‐hydroxytryptamine (5‐HT), 5‐hydroxyindole acetic acid (5‐HIAA), dopamine, and 3‐methoxytyramine were investigated by reversed‐phase high‐performance liquid chromatography with electrochemical detection after precolumn derivatization with (2R)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (NPCA). We observed a stereoselective difference in the effects of the KYN enantiomers. Only D‐KYN, not L‐KYN, caused a significant increase in urinary 5‐HT levels within 30 min after its administration. With regard to the metabolites, urinary 3‐MT level was increased by D‐KYN administration. On the other hand, no significant change in the DA level was observed after administration of either D‐KYN or L‐KYN. These results suggest that D‐KYN could affect the activity of neuroactive amines, especially 5‐HT, in vivo. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Stereoselective plasma protein binding of amlodipine
Authors: Maddi Srinivas , Yamsani Madhusudan Rao , Seeling Andreas , Scriba Gerhard K. E.
Published: June 2009

The binding of the (R)‐ and (S)‐enantiomers of amlodipine to bovine serum albumin (BSA), human serum albumin (HSA), α1‐acid glycoprotein (AGP), and human plasma (HP) was studied by equilibrium dialysis over the concentration range of 75–200 μM at a protein concentration of 150 μM. Unbound drug concentrations were determined by enantioselective capillary electrophoresis using 50 mM phosphate buffer, pH 2.5, containing 18 mM α‐cyclodextrin as background electrolyte. Saturation of the protein binding sites was not observed over the concentration range tested. Upon application of racemic amlodipine besylate, (S)‐amlodipine was bound to a higher extend by HSA and HP compared with (R)‐amlodipine, whereas the opposite binding of the enantiomers was observed for BSA and AGP. Scatchard analysis was used to illustrate the different binding affinities of amlodipine besylate enantiomers to BSA, HSA and AGP. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Effect of bile and lipids on the stereoselective metabolism of halofantrine by rat everted‐intestinal sacs
Authors: Patel Jigar P. , Korashy Hesham M. , El‐Kadi Ayman O.S. , Brocks Dion R.
Published: June 2009

The everted rat intestinal‐sac model was utilized to assess the effect of post‐prandial conditions on the stereoselective intestinal metabolism of halofantrine to its active metabolite desbutylhalofantrine. Everted intestinal sacs were incubated with (±)‐halofantrine HCl in the presence of simulated bile solution (containing lecithin, lipase and cholesterol) and lipids to mimic post‐prandial conditions in the small intestine. The halofantrine enantiomer concentrations in intestinal sacs were relatively constant in the presence of bile, but decreased significantly on addition of lipids to the incubation media. Formation of desbutylhalofantrine enantiomers was inversely proportional to bile concentration whereas addition of lipids in the presence of bile caused a significant decrease in desbutylhalofantrine:halofantrine ratio of (−) enantiomers. Pre‐treatment of rats with peanut oil had no significant effect on desbutylhalofantrine formation in the incubated sacs or microsomal preparations, nor did it affect the expression of intestinal cytochrome P450. Addition of extra cholesterol to the bile incubations caused a significant increase in tissue halofantrine and desbutylhalofantrine concentrations, which as for lower cholesterol, were diminished on addition of other lipids. The results were consistent with previous in vivo evaluations showing that the desbutylhalofantrine to halofantrine ratio was decreased by the ingestion of a high fat meal. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Produktdesign disperser Stoffe: Industrielle Sprühtrocknung
Authors: Rähse W. , Dicoi O.
Published: June 2009

Die in Sprühtürmen durchgeführte Zerstäubungstrocknung stellt das Standardverfahren zur Herstellung von Pulvern aus Flüssigkeiten (Lösungen, Suspensionen, Emulsionen) dar. Dieser an sich einfache Prozess bietet viele Parameter zur Optimierung. So werden in der Industrie auch bei etablierten Verfahren Leistungssteigerungen, Energieverbräuche, Produktqualitäten, Anlagensicherheit und Abluft regelmäßig diskutiert. Leistungssteigerungen lassen sich über den Einsatz von deutlich mehr Düsen, die entsprechend kleiner sind, erreichen. Die dann mögliche, erhöhte Menge an gesprühter Flüssigkeit pro m3 Gas/h senkt den spezifischen Energieverbrauch. Das Partikeldesign (Form, Schüttgewicht, Rieselfähigkeit) wird über die stoffabhängige Strukturbildung während des Trocknungsvorganges bestimmt. In Abhängigkeit von den Stoffeigenschaften und vom Feststoffgehalt ist die getrocknete Partikel größer oder kleiner als der gesprühte Tropfen. Im Vergleich zu den Tropfengrößen weisen die am Turmkonus ausgetragenen Produkte infolge von Agglomerationen deutlich höhere Werte für die Partikeldurchmesser auf. Zum sicheren Betreiben des Zerstäubungsturms müssen Zündquellen vermieden werden. Viele organisch basierte Rezepturen erfordern das Arbeiten unter Stickstoff. Eine interessante Alternative stellt die Trocknung mit überhitztem Wasserdampf dar, weil kein Abgas entsteht und sich die Energie weitgehend zurückgewinnen lässt. Das übliche Scale‐up vom Labor über das Technikum in die Produktion ist nicht möglich. Die Vorgehensweise über die Auswahl der Düsen wird beschrieben.
Adsorption and flotation studies with quartz: Part I. Adsorption of calcium, hydrogen and hydroxyl ions on quartz
Authors: Ahmed S. M. , Van Cleave A. B.
Published: June 2009

The adsorption of calcium ions from aqueous solutions on − 65 + 200 mesh quartz has been measured using Ca45 as a tracer. Results are given for initial Ca++ ion concentrations of (4.2 to 11.5) × 10−4 gm. ions/liter over the pH range 4 to 12. Changes in pH occurring during the adsorption have also been determined. The mechanisms of cationic adsorption on quartz in aqueous media, and the activation of quartz surfaces for flotation with anionic collectors are critically discussed.
Adsorption and flotation studies with quartz: Part II. The adsorption of laurate and myristate on quartz
Authors: Ahmed S. M. , Van Cleave A. B.
Published: June 2009

The adsorption of laurate and myristate ions on quartz from solutions containing (1 to 25) × 10−5 gm. ions/liter of adsorbate at different pH values, both in the absence and in the presence of Ca++ ions, has been measured using C14‐labelled compounds as tracers. The results have been correlated with the flotation behavior of quartz as determined by Hallimond tube and bubble pick up techniques.
Chemical and physical limits on vapor‐phase diffusion flames of droplets
Authors: Brzustowski T. A.
Published: June 2009

The combustion of a fuel droplet can be described by a quasi‐steady theory at pressures up to about 1/10 of the critical pressure of the fuel. Finite rates of chemical reaction and evaporation impose lower bounds on the product of pressure and droplet size for which the theory is valid. An unsteady droplet theory becomes necessary for pressures between the highest pressure for a quasi‐steady theory and the critical pressure.

Unsteady heat transfer and diffusion of dense gas are the significant processes in the combustion of a liquid fuel above its critical pressure. The burning rates above the critical pressure are likely of the same order as at lower pressures.
The influence of surfactants on mass transfer around spheres
Authors: Lochiel A. C.
Published: June 2009

Equations are derived to predict the effect of trace surface‐active impurities on mass transfer across a spherical interface.

Transfer in the bulk phase surrounding spheres with both rapid and slow internal circulation, and moving in creeping flow, is shown to decrease on increasing the surfactant concentration.

Drag and transfer equations for contaminated rapidly‐circulating spheres moving at high Reynolds numbers are in semi‐quantitative agreement with published data.

The influence of surface‐active contaminants on drag and transfer decreases as the viscosity of the bulk phase is increased.
Some further observations on tubular reactor stability
Authors: Amundson Neal R.
Published: June 2009

A necessary and sufficient condition for stability of the empty adiabatic tubular reactor with axial mixing is derived which depends upon steady state information alone. The stability conditions require the solution of a linear ordinary differential equation and the character of this solution determines the stability or instability of the system without the use of transient calculation. The lumped constant reactor is always stable. The method of computation requires a minimum amount of memory capacity in a digital computer and could be carried out on an analogue computer with ease.
A kinetic study of the regeneration of a dehydrogenation catalyst
Authors: Mickley Harold S. , Nestor John W. , Gould Leonard A.
Published: June 2009

Experimental measurements were made of the rate at which coke, deposited in situ, was burned off a porous chromia‐alumina dehydrogenation catalyst by hot air. Over the range of variables examined, the regeneration rate passed from complete dependence on chemical kinetics to complete dependence on the rate of oxygen diffusion through the catalyst pores. A model of the regeneration process which accounts for simultaneous pore diffusion and chemical kinetics was successfully fitted to the experimental data.