bluuebunny/crossref_metadata_2025 huggingface dataset:
Covalent immobilization of α‐amylase onto UV‐curable coating
Authors: Yarar Ümran , Kahraman Memet Vezir
Published: August 2009

A UV‐curable N‐(4‐sodiumsulfophenyl)‐maleimide monomer was synthesized, and its potential for enzyme binding was investigated. The bromine, which is used to activate the synthesized monomer for covalent attachments, has the advantage of giving reaction with the surface groups of enzyme under very mild conditions (0°C, 30 min). In this procedure, sulfonyl bromide pendant monomer reacted with amino groups of the protein to form sulfonamide bonds. Polymeric support was prepaped by UV‐curing technique. The water adsorption value was found to be less than 1%. The enzyme‐bounding yield was found to be 68.18 ± 4.20 mg/g monomer. The maximum activity was observed at pH 6.5. Immobilization did not change the pH‐dependency of the enzyme activity. It was found that the optimum temperature for the free enzyme was ∼ 30°C, whereas it shifted to nearly 50°C for the immobilized enzyme. Free enzyme lost its activity completely within 15 days. Immobilized enzyme lost only 30% of its activity in 30 days. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study on morphology and viscoelastic properties of PP/PET/SEBS ternary blend and their fibers
Authors: Mostofi N. , Nazockdast H. , Mohammadigoushki H.
Published: August 2009

The morphology development of polypropylene (PP)/polyethylene terephthalate (PET)/styrene‐ethylene‐butylene‐styrene (SEBS) ternary blends and their fibers were studied by means of scanning electron microscopy (SEM) in conjunction with the melt linear viscoelastic measurements. The morphology of the blends was also predicted by using Harkin's spreading coefficient approach. The samples varying in composition with PP as the major phase and PET and SEBS as the minor phases were considered. Although SEM of the binary blends showed matrix‐dispersed type morphology, the ternary blend samples exhibited a morphological feature in which the dispersed phase formed aggregates consisting of both PET and SEBS particles distributed in the PP matrix. The SEM of the blend samples containing 30 and 40 wt % of total dispersed phase showed an agglomerated structure formed between the aggregates. The SEM of the PP/PET binary fiber blends showed long well‐oriented microfibrils of PET whereas in the ternary blends, the microfibrils were found to have lower aspect ratio with a fraction of the SEBS stuck on the microfibril fracture surfaces. These results were attributed to a core‐shell type morphology in which the PET and SEBS formed the core‐shells distributed in the matrix. The melt viscoelastic behavior of the ternary blends containing less than 30 wt % of the total dispersed phase was found to be similar to the matrix and binary blend samples whereas the samples containing 30 and 40 wt % of dispersed phases exhibited a pronounced viscosity upturn and nonterminal storage modulus in low frequency range. These results were found to be in good agreement with the morphological results. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A novel nonviral gene delivery vector: Low‐molecular‐weight polyethylenimine‐graft‐ovalbumin
Authors: Chen Dan , Liu Yang , Lehtinen Anna , Jiang Qiying , Liu Jun , Zhou Jun , Huang Hongliang , Wang Qingqing , Tang Guping , Shi Pei Hua
Published: August 2009

A novel vector for gene delivery was synthesized. Here the ovalbumin (OVA) acts as a core and low‐molecular‐weight PEI600 was grafted to its surface. The finally product was characterized (1H‐NMR, UV, and TGA) and its biophysical properties such as DNA condensing, particle size, and zeta potential were determined. The agarose gel assay indicated that OVA‐PEI600 could efficiently condense plasmid DNA. Its particle size was about 150 nm and zeta potential was around +20 mV. The MTT assay showed that the cytotoxicity of OVA‐PEI600 was less than PEI25 kDa. Its transfection efficiency in SKOV‐3 and HepG2 cell lines was higher than that of PEI600 and comparable to PEI25 kDa. In vivo, luciferase activity could be tested in liver, spleen, kidney, lung, and blood serum, respectively, in mice. The core‐shell structure of OVA‐PEI600 provided a novel strategy for nonviral gene delivery. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Properties of isocyanate‐reactive waterborne polyurethane adhesives: Effect of cure reaction with various polyol and chain extender content
Authors: Rahman Mohammad Mizanur , Lee Won‐Ki
Published: August 2009

Three series of isocyanate‐reactive waterborne polyurethane adhesives were prepared with various contents of chain extender (4.25/8.25/12.50 mol %) and polyol (20.75/16.75/12.50 mol %). Each series had a fixed amount of excess (residual) NCO group (0.50–2.00 mol %). FTIR and 1H‐NMR spectroscopy identified the formation of urea crosslink structure mainly above 80°C of various cure temperatures (20–120°C) with excess diisocyanate. The molecular weight, tensile strength, Young's modulus, and adhesive strength depend on excess NCO content and cure temperature and also varied with polyol and chain extender content. The optimum cure temperature was 100°C for all the samples. The tensile strength, Young's modulus, and adhesive strength increased with increasing cure temperature above 60°C up to the optimum temperature) (100°C) and then almost leveled off. Among all the samples, the maximum values of tensile strength, Young's modulus, and adhesive strength were found with 63.22 wt % polyol, 0.93 wt % chain extender, and 1.50 mol % excess (residual) NCO content at 100°C optimum cure temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Evaluating fouling‐resistance and fouling‐release performance of smart polyurethane surfaces: An outlook for efficient and environmentally benign marine coatings
Authors: Joshi Ravi G. , Goel Achin , Mannari Vijay M. , Finlay John A. , Callow Maureen E. , Callow James A.
Published: August 2009

Various environmentally friendly approaches have been studied in recent years for effectively controlling biofouling on marine structures. Among these, two distinct and successful approaches are (1) the use of hydrophilic surfaces that control biofouling by resisting the adhesion of fouling organisms and (2) the use of hydrophobic elastomeric surfaces that function by facilitating their easy removal. In this study, we attempted to investigate amphiphilic surfaces for their effectiveness in controlling marine biofouling. Polyurethane surfaces containing tethered hydrophilic, hydrophobic, and amphiphilic moieties were designed and synthesized. The wetting behaviors of these surfaces, as a function of the external environment, were studied by dynamic contact angle (DCA) measurements and their morphologies by atomic force microscopy (AFM). The results from DCA measurements and AFM postulate interesting characteristics of the amphiphilic surfaces. Bioassays with the green fouling alga Ulva showed that the amphiphilic surfaces had fouling‐resistance and fouling‐release potential and provide an insight into the scope of the development of smart marine coatings. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Empirical models for end‐use properties prediction: Application to injection molding of some polyethylene resins
Authors: Costa M. C. B. , Jardini A. L. , Lima N. M. N. , Embiruçu M. , Maciel M. R. Wolf , Filho R. Maciel
Published: August 2009

A great challenge related to polymers research has been the development of reliable models enabling prediction of polymer end‐use properties according to the initial operational conditions—either during the polymerization process or the transformation process phases. These models can be utilized to produce final devices with specified properties in a more economic and faster way. The first step for building up such kind of model is the information about the relationship between the intrinsic properties, which is a convenient way to develop the models. The intention is to optimize the operational conditions of transformation systems, resulting in better products with lower costs. Empirical models are suitable workable solutions to represent complex systems in which it is difficult and expensive or too time‐consuming to develop a detailed deterministic model. Bearing this in mind, this article aims to build‐up empirical models relating intrinsic and end‐use properties of polymers, which can be applied in the injection plastic molding. The development was carried out through resins characterizations together with the impact quantification of process operating variables including their interactions. Polyethylene resins produced in a second generation petrochemical industry were used as a case study. The first generation industries include the production of basic products from naphtha, whereas the second generation involves the transformation of basic petrochemicals, such as ethane and propane, into thermoplastic resins, polyethylene, and polypropylene. The developed models were compared to experimental data and good predictions were obtained. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Carbohydrate‐based poly(ester‐urethane)s: A comparative study regarding cyclic alditols extenders and polymerization procedures
Authors: Marín Romina , Muñoz‐Guerra Sebastián
Published: August 2009

A set of segmented poly(ester‐urethane)s were prepared from diisocyanates HDI or MDI and using 1,4‐butanediol and D‐glucose‐derived cyclic diols (1,4 : 3,6‐dianhydro‐D‐glucitol (isosorbide) or 2,4;3,5‐di‐O‐methylidene‐D‐glucitol (gludioxol) or mixtures of them) as extenders. Hydroxyl end‐capped polycaprolactone with a molecular weight of 3000 g·mol−1 was used as soft segment. Two polymerization methods, in solution and in bulk, were applied for the synthesis of these poly(ester‐urethane)s. The influence of the preparation procedure and composition in cyclic extender on synthesis results, structure, and properties of the novel poly(ester‐urethane)s was comparatively evaluated and discussed. The effect of replacement of 1,4‐butanediol by isosorbide or gludioxol on hydrodegradability was also assessed; the hydrolysis rate increased noticeably with the presence of glucitol derived units, although degradation of the polymers took place essentially by hydrolysis of the polyester soft segment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Tensile testing of individual ultrathin electrospun poly(L‐lactic acid) fibers
Authors: Jaeger Dominik , Schischka Jan , Bagdahn Jörg , Jaeger Raimund
Published: August 2009

The mechanical properties of ultrathin electrospun poly(L‐lactic acid) (PLLA) fibers were studied by performing tensile tests on individual fibers. The tests were carried out on microelectronic mechanical systems (MEMSs) which were developed for characterizing the mechanical properties of thin polymer fibers. Force–displacement curves were obtained from video recordings of the experiments which were carried out in a scanning electron microscope. Each video was processed with an image processing routine to determine the elongation of the fiber and the elastic deformation of a component of the MEMS which yielded the force acting on the specimen. PLLA fibers with diameters ranging from 150 nm to 2 μm were tested. The elastic modulus and the ultimate tensile strength of the fibers increased significantly for fiber diameters below 1 μm. This indicates a higher degree of orientation of the polymer chains in ultrathin fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A thermal and rheological investigation during the complex cure of a two‐component thermoset polyurethane
Authors: Papadopoulos Eleni , Ginic‐Markovic Milena , Clarke Stephen
Published: August 2009

The complex cure kinetics of the reaction between oligomeric diphenylmethane diisocyanate (PMDI) and glycerol was characterized through thermal and rheological techniques. Isoconversional analysis of Differential scanning calorimetry (DSC) data resulted in the activation energy varying with conversion. Isothermal analysis gave activation energies ranging from 5 kJ/mol to 33.7 kJ/ mol, whereas nonisothermal data gave values for the activation energy ranging from 49.5 to 55 kJ/mol. Incomplete cure was evident in isothermal DSC, becoming diffusion controlled in the final stages of cure. DMA analysis on the cured material gave a glass transition temperature of 104 ± 3°C, which was evidence for vitrification of the curing system. The primary and secondary hydroxyl group reactivity was dependant on the isothermal cure temperature. Rheological studies of viscosity increase and tan δ changes with time revealed a complex cure process, with primary and secondary hydroxyl reactivity also showing dependence on isothermal cure temperatures, reflecting similar results obtained from isothermal DSC studies. The independence of tan δ on frequency was used to determine the point where the polymer formed an infinite network and was no longer able to flow, providing an overall activation energy attained at the gel point of 77.4 ± 4.4 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Stress–strain curve modeling and length effect of polymer concrete subjected to flexural compressive stress
Authors: Yeon Kyu‐Seok
Published: August 2009

Stress–strain relation, stress‐block parameters, and length effect of polymer concrete flexural compression members were experimentally investigated. For these purposes, a series of C‐shaped polymer concrete specimens subjected to a flexural compressive load were tested. On the basis of the test results, we proposed an equation to predict stress–strain relation of polymer concrete. In this model, we took account of the slope of descending branch beyond the peak stress point of a single curve. The proposed equation was numerically integrated to compute the rectangular stress‐block parameters. Computed β1 was greater than the values prescribed in ACI 318 Code for cement concrete, and α1 was about 0.85 that is similar to the value regulated in ACI. A series of C‐shaped specimens were also tested to study the length effect. The test results were curve fitted to obtain parameters for the existing length effect equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
A new methodology in the study of PVAc‐based adhesive formulations
Authors: Salvini A. , Saija L. M. , Finocchiaro S. , Gianni G. , Giannelli C. , Tondi G.
Published: August 2009

The role of the main components of a PVAc‐based wood adhesive formulation in the formation and performance of the adhesive joint was investigated. A new analytical methodology was applied to carry out the chemical separation and characterization of the adhesive components present in the bond line. By using extraction techniques on the wet and dry glues it was possible to observe the variation in the solubility of the adhesive components, for different glue formulations. The swollen‐state NMR technique proved to be a very useful tool to characterize the insoluble parts present in the adhesive films. These findings, when put into relation to some specific properties of the adhesive joints, contribute to the understanding of the mechanisms involved in the adhesion process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of colloidal carbon sphere/rigid polyurethane foam composites
Authors: Zhuang Zhe‐Hui , Yang Zhen‐Guo
Published: August 2009

Sucrose decomposed under hydrothermal conditions, generating colloidal carbon spheres (CCSs) with a perfectly spherical morphology. X‐ray diffraction indicated that the main component of the CCSs was disordered carbon, and massive hydroxyl groups existed on the surface, as confirmed by Fourier transform infrared spectroscopy. CCSs were first introduced into polyurethane foams (PUFs), and CCS‐reinforced PUF (PUF/CCS) composites were synthesized. The introduction of CCSs did not increase the viscosity of polyol/CCS blends significantly. The good dispersion of CCSs and the compatibility between CCSs and polyurethane were confirmed by transmission electron microscopy measurements. The results of mechanical testing showed that PUF/CCS composites exhibited greatly improved mechanical properties in comparison with neat PUFs, and this could be ascribed to the finer cell structure of the PUF/CCS composites, which was inspected with scanning electron microscopy. Thermogravimetric analysis indicated that the effects of CCSs on the thermal stability of the foams were slight. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Perspectives on social tagging
Authors: Ding Ying , Jacob Elin K. , Zhang Zhixiong , Foo Schubert , Yan Erjia , George Nicolas L. , Guo Lijiang
Published: August 2009

Social tagging is one of the major phenomena transforming the World Wide Web from a static platform into an actively shared information space. This paper addresses various aspects of social tagging, including different views on the nature of social tagging, how to make use of social tags, and how to bridge social tagging with other Web functionalities; it discusses the use of facets to facilitate browsing and searching of tagging data; and it presents an analogy between bibliometrics and tagometrics, arguing that established bibliometric methodologies can be applied to analyze tagging behavior on the Web. Based on the Upper Tag Ontology (UTO), a Web crawler was built to harvest tag data from Delicious, Flickr, and YouTube in September 2007. In total, 1.8 million objects, including bookmarks, photos, and videos, 3.1 million taggers, and 12.1 million tags were collected and analyzed. Some tagging patterns and variations are identified and discussed.
Supramolecular Surface Modification and Solubilization of Single‐Walled Carbon Nanotubes with Cyclodextrin Complexation
Authors: Zu Sheng‐Zhen , Sun Xu‐Xia , Liu Yuanqin , Han Bao‐Hang
Published: August 2009

A novel approach to solubilize single‐walled carbon nanotubes (SWCNTs) in the aqueous phase is described by employing supramolecular surface modification. We use cyclodextrin complexes of synthetic molecules that contain a planar pyrene moiety or a bent, shape‐fitted triptycene moiety as a binding group connected through a spacer to an adamantane moiety that is accommodated in the cyclodextrin cavity. The binding groups attach to the sidewalls of SWCNTs through a π–π stacking interaction to yield a supramolecular system that allows the SWCNTs to dissolve in the aqueous phase through the formed hydrophilic cyclodextrin shell. The black aqueous SWCNT solutions obtained are stable over a period of months. They are characterized through absorbance, static, and time‐resolved fluorescence spectroscopy as well as Raman spectroscopy, TEM, and fluorescence‐decay measurements. Furthermore, the shape‐fitted triptycene‐based system shows a pronounced selectivity for SWCNTs with a diameter of 1.0 nm.
Lewis Acid‐Assisted Ene Cyclization of 2‐Azetidinone‐Tethered Enals: Synthesis of Enantiopure Carbacepham Derivatives
Authors: Alcaide Benito , Almendros Pedro , Pardo Carmen , Rodríguez‐Ranera Carolina , Rodríguez‐Vicente Alberto
Published: August 2009

Diastereocontrolled Lewis acid‐catalyzed preparation of enantiopure carbacepham derivatives have been developed starting from 2‐azetidinone‐tethered enals. The BF3⋅Et2O‐promoted reaction of alkenylaldehydes 1 and 16 is effective as carbocyclization protocol to afford 4‐substituted 5‐hydroxycarbacephams or 3‐substituted 4,5‐dihydroxycarbacephams, respectively, by a type I carbonyl‐ene reaction, while the BF3⋅Et2O or SnCl4‐mediated type II carbonyl‐ene cyclization of alkenylaldehydes 2 furnishes 3‐methylene 5‐hydroxycarbacephams along with the corresponding 3‐halo 5‐hydroxycarbacepham. The stereochemical outcome of these carbonyl‐ene cyclizations leading to carbacepham derivatives can be explained in terms of six‐membered, cyclic chair‐like transition‐state models. The formation of halocarbacepham derivatives is proposed to proceed by a stepwise mechanism.
Untersuchungen zum vertikalen Tragverhalten von Spundwänden
Authors: Grabe Jürgen , Schallück Christoph , Kinzler Steffen
Published: August 2009

Spundwände werden im Wesentlichen auf Biegung infolge einer Belastung durch Erd‐ und Wasserdrücke beansprucht. Sie können aber auch zum Abtrag von Vertikallasten dienen. Das Tragverhalten von Spundwänden ist bei genauer Betrachtung äußerst komplex, da diesem eine räumlich und zeitlich gekoppelte Boden‐Bauwerk‐Interaktion zugrunde liegt. Für die praktische Bemessung muss das Tragverhalten daher stark idealisiert werden. Die Rechtfertigung der dafür notwendigen Modellvorstellungen sowie deren Vereinfachungen und Annnahmen sind, wie häufig in der Geotechnik, hauptsächlich durch Erfahrung begründet.

Researching the vertical load bearing behaviour of sheet piles.

Sheet pile walls are mainly used to carry loads caused by earth and water pressure via bending. In special cases these walls can be used to transfer vertical loads to the subsoil. The complex load bearing behaviour of sheet pile walls is caused by the sterical and temporal coupled soil structure interaction. For practical design the load bearing behaviour needs to be idealised. The apologies used to explain the model conceptions as well as their simplifications are, as usual in geotechnics, mainly motivated by operating experience.
Hochwasserschutz im Land Bremen – Anpassung an prognostizierte Klimaänderungen
Authors: Bleck Matthias , Krebs Hauke , Scholz Anne , Spekker Heiko
Published: August 2009

Im Beitrag wird auf Besonderheiten bei der Umsetzung des Generalplans Küstenschutz Niedersachsen/Bremen im Land Bremen eingegangen.

Im ersten Teil werden die Grundlagen und Ergebnisse des Generalplans sowie die administrative Aufstellung des Landes Bremen zur Anpassung des Hochwasserschutzes beschrieben. Das Instrument der Kostenvergleichsrechnung wird vorgestellt, welches in Bremen bereits im frühen Projektstadium zur Bewertung der Vorzugslösungen eingesetzt wird.

Ein wichtiger Aspekt bei der Umsetzung des Generalplans sind die technischen Anforderungen, die sich aus den bestehenden Hochwasserschutzanlagen ergeben. Weiterhin müssen im Land Bremen die Maßnahmen zum Hochwasserschutz im Wesentlichen unter Berücksichtigung der bestehenden konstruktiv geprägten Ufer (Spundwände und Kaianlagen) umgesetzt werden. Dabei sind spezielle Anforderungen hinsichtlich der aktuellen und zukünftigen Nutzung insbesondere in den Hafenrevieren zu berücksichtigen. Beispielhaft werden begleitende Projekte der INROS LACKNER AG vorgestellt.

Flood protection in the Federal State and the city of Bremen by adjustment of climate changes.

The present article describes how the Federal State and the Free Hanseatic City of Bremen adapts its flood protection with respect to climate changes and global sea level rise.

Design basics are compiled in the “Generalplan Küstenschutz Niedersachsen/Bremen” (General Plan for Coastal Protection – Lower Saxony/Bremen). Main results of the general plan will be described and administrative aspects of the adaptation of the flood protection elements in Bremen will be lined out. Special technical requirements as the consideration of existing walls and dikes will be described. Also requirements from harbour operation, recreational use and urban architecture have to be considered as the Bremen port partly undergoes a rapid change in this regard.

The instrument of cost analysis will be introduced which is utilised in Bremen at an early stage of planning in order to develop cost effective measures of public founded projects.

Mentioned topics will be described based on projects carried out by INROS LACKNER AG.
Erdbebenertüchtigung des Feuerwehrgebäudes in Basel durch schwimmende Lagerung
Authors: Bachmann Hugo
Published: August 2009

Kürzlich wurde das Hauptgebäude der Berufsfeuerwehr Basel‐Stadt aus dem Jahre 1943 auf spezielle Erdbebenlager aus Gummi und auf Gleitlager gestellt. Es handelt sich um die erste derartige Erdbebenertüchtigung eines bestehenden Gebäudes nördlich der Alpen. Im Vergleich zu einer konventionellen Verstärkung waren die Baukosten bedeutend geringer, und es war keine temporäre Ausquartierung des Betriebes in ein teures Provisorium erforderlich. Zudem ist die resultierende Erdbebensicherheit erheblich größer und die Schadensanfälligkeit bei schweren Erdbeben wesentlich geringer als es bei einer konventionellen Verstärkung der Fall wäre.

Seismic upgrading of the fire brigade building in Basel by base isolation.

Recently, the main building of the professional fire brigade of the city and canton Basel‐Stadt built in the year 1943 was placed on special seismic elastomeric bearings and on sliding bearings. This is the first such seismic upgrading of an existing building in the north of the Alps. Compared to a conventional strengthening the buildingcosts were significantly smaller, and no temporary transfer of the operation into an expensive provisional building was necessary. Moreover, the resulting seismic safety is considerably higher and the vulnerability to a severe earthquake essentially smaller than in case of a conventional strengthening.
DIN 1052:2008‐12 Neue Grundlagen für Entwurf, Berechnung und Bemessung von Holzbauwerken – Teil 5 (2): Aussteifungen von Holztragwerken (Fortsetzung aus Heft 7/09 und Schluss)
Authors: Lißner Karin , Rug Wolfgang , Steinmetz Dieter
Published: August 2009

Es werden die Grundlagen zur Aussteifung von Holztragwerken dargelegt und an Beispielen erläutert.

DIN 1052:2008‐12 – New basics for design, calculation and dimensioning of timber structures, Part 5 (2): Construction of bracing in wooden structures.

Basics of bracing in wooden structures are given and amplified by several examples. (Continuation of part 5 (1), number 7/09)
Softwaregestützte Kostenermittlung für die Gebäudeinstandsetzung
Authors: Beecken Christoph A. , Levchenko Taras
Published: August 2009

In diesem Beitrag werden Möglichkeiten der softwaregestützten Kostenermittlung für die Instandsetzung vorgestellt, die in den vergangenen Jahren im Rahmen mehrerer Instandsetzungsprojekte entwickelt wurden und für unterschiedlichste Gebäudetypen anwendbar sind. Schwerpunkte sind die zügige und präzise Schadenserfassung und ‐bewertung als Schlüsselfaktoren für die Ermittlung der zu erwartenden Baukosten.

Am konkreten Beispiel werden die Vorteile der softwaregestützten Schadenserfassung und ‐bewertung beschrieben, und es wird der Bezug zur Praxis hergestellt.

Computer aided cost calculation for building repair.

This paper shows ways of software aided cost calculation for rehabilitation of buildings, which have been developed in recent years in several repair projects and which are applicable for various building types.

The advantages of automated damage assessment and evaluation are described at an example of a parking garage and are related to the practice.
Stability of cucurbitacin E in human plasma: chemical hydrolysis and role of plasma esterases
Authors: Saade Myriam , Magdalou Jacques , Ouaini Naim , Greige‐Gerges Helene
Published: August 2009

It was shown previously that the anticancerous cytotoxic oxygenated triterpenes, cucurbitacin E (Cuc E) and its deacetylated form, cucurbitacin I (Cuc I), interacted differently with human serum albumin.

In this study, the biochemical stability of Cuc E was investigated in vitro by reverse‐phase high performance liquid chromatography. The hydrolysis rate in acidic and alkaline solutions, and in enzymatic conditions in human plasma and in purified plasma esterase solutions of butyrylcholinesterase and albumin, was compared with that measured in phosphate buffer saline (pH 7.4).

Cuc E hydrolysis was detected in all the in vitro tests, but the extent of hydrolysis varied according to the different enzymatic and non‐enzymatic conditions. A remarkable rapid hydrolysis of Cuc E was detected in acidic and alkaline solutions. A significant rate of hydrolysis of Cuc E was monitored in human plasma and was associated with the detection of Cuc I.

The stability of Cuc E was greatly enhanced in the presence of albumin. However, purified butyrylcholinesterase had no effect on Cuc E stability. Among specific inhibitors of plasma esterases, only EDTA increased Cuc E stability, suggesting that paraoxonase is the human plasma esterase involved in the hydrolysis of Cuc E. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of Coptis Chinensis on pharmacokinetics of flavonoids after oral administration of Radix Scutellariae in rats
Authors: Shi Rong , Zhou Hui , Liu Zhaoming , Ma Yueming , Wang Tianming , Liu Yingying , Wang Changhong
Published: August 2009

Radix Scutellariae (RS) and Coptis Chinensis (CC) are the most popular components in traditional Chinese medicine prescriptions. Flavonoids are the main effective ingredients in RS and berberine is the main effective ingredient in CC. The aim of this study was to determine the influence of CC on the pharmacokinetics of flavonoids following the administration of RS in rats and to investigate the effects of CC on the pharmacokinetic mechanism. Rats were administered RS or RS+CC by intragastric gavage (ig). Plasma concentrations of baicalin (baicalein 7‐glucuronide) and wogonoside (wogonin 7‐glucuronide) were measured by HPLC. Pharmacokinetic parameters were calculated from the plasma concentration time curve. The effect of CC on the metabolism of flavonoids in RS by rat intestinal flora was studied using rat fecal suspensions after ig administration of CC. The effect of berberine on the bi‐directional transport of baicalein and baicalin was studied in Caco‐2 monolayer models. The effect of CC on the metabolism of baicalein and baicalin by the liver was studied using rat liver microsomes after ig administration of CC. Compared to RS alone, RS+CC decreased AUC and Cmax of baicalin and wogonoside. CC decreased the hydrolyzation of baicalin and wogonoside by intestinal flora. Berberine decreased the amount of baicalein transported to the basolateral side and the amount of baicalin which appeared at the basolateral side. The results showed that CC may decrease the bioavailability of baicalin and wogonoside in RS and the mechanism was related to CC decreasing the transport of flavonoid aglycones from the mucosa side to the serosal side and the hydrolyzation of flavonoids by inhibiting intestinal flora. Copyright © 2009 John Wiley & Sons, Ltd.
Classification of Therapy Resistance Based on Longitudinal Biomarker Profiles
Authors: Kohlmann Mareike , Held Leonhard , Grunert Veit Peter
Published: August 2009

To classify patients either as resistant or non‐resistant to HIV therapy based on longitudinal viral load profiles, we applied longitudinal quadratic discriminant analysis and examined various measures, mainly derived from the Brier Score, to assess the biomarker performance in terms of discrimination and calibration. The analysis of the application data revealed an increase in performance by using longer profiles instead of single biomarker measurements. Simulations showed that the selection of mixed models for the estimation of the group‐specific discriminant rule parameters should be based on BIC, rather than on the best performance measure. An incorrect model selection can lead to spuriously better or worse performance as misclassification and classification certainty regards, especially with increasing length of the profiles and for more complex models with random slopes.
ILPR repeats adopt diverse G‐quadruplex conformations that determine insulin binding
Authors: Schonhoft Joseph D. , Das Arijit , Achamyeleh Firehiwot , Samdani Sheema , Sewell Abby , Mao Hanbin , Basu Soumitra
Published: August 2009

The insulin‐linked polymorphic region (ILPR) is a VNTR region located upstream of the insulin (INS) gene consisting of the repeat 5′‐ACAGGGGTGTGGGG (repeat a) and several less abundant sequence repeats (b–n). Here, we have investigated the structural polymorphism of G‐quadruplexes formed from the most common repeat sequences (a–c) and their effect on insulin protein binding. We first established that the ILPR repeats “b” and “c” can form quadruplex structures. Insulin has previously been shown to bind a G‐quadruplex formed by a dimer of the repeat “a”. Our findings show that insulin binds preferentially to the repeat “a” G‐quadruplex (Kd = 0.17 ± 0.03 μM) over G‐quadruplexes formed from other ILPR repeats that were tested (Kds from 0.71 ± 0.15 to 1.07 ± 0.09 μM). Additionally, the Watson‐Crick complementary relationship between the loop regions of repeat “a” (ACA and TGT) seemingly play an important role in favoring a specific G‐quadruplex conformation, which based on our data is critical for insulin binding. Affinity for insulin is reduced in sequences lacking the putative WC complementarity, however upon engineered restoration of complementarity, insulin binding is recovered. A DMS footprinting assay on the repeat “a” G‐quadruplex in the presence of insulin, combined with binding affinities for ILPR mutants led to identification of a loop nucleotide critical for binding. Uniquely, insulin shows clear preference for binding to the G‐quadruplexes with the more antiparallel feature. Collectively, our results illustrate the specific nature of insulin binding to the ILPR G‐quadruplexes and begin to provide molecular details on such interactions. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 21–31, 2010.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Modeling changes in biomass composition during microwave‐based alkali pretreatment of switchgrass
Authors: Keshwani Deepak R. , Cheng Jay J.
Published: August 2009

This study used two different approaches to model changes in biomass composition during microwave‐based pretreatment of switchgrass: kinetic modeling using a time‐dependent rate coefficient, and a Mamdani‐type fuzzy inference system. In both modeling approaches, the dielectric loss tangent of the alkali reagent and pretreatment time were used as predictors for changes in amounts of lignin, cellulose, and xylan during the pretreatment. Training and testing data sets for development and validation of the models were obtained from pretreatment experiments conducted using 1–3% w/v NaOH (sodium hydroxide) and pretreatment times ranging from 5 to 20 min. The kinetic modeling approach for lignin and xylan gave comparable results for training and testing data sets, and the differences between the predictions and experimental values were within 2%. The kinetic modeling approach for cellulose was not as effective, and the differences were within 5–7%. The time‐dependent rate coefficients of the kinetic models estimated from experimental data were consistent with the heterogeneity of individual biomass components. The Mamdani‐type fuzzy inference was shown to be an effective approach to model the pretreatment process and yielded predictions with less than 2% deviation from the experimental values for lignin and with less than 3% deviation from the experimental values for cellulose and xylan. The entropies of the fuzzy outputs from the Mamdani‐type fuzzy inference system were calculated to quantify the uncertainty associated with the predictions. Results indicate that there is no significant difference between the entropies associated with the predictions for lignin, cellulose, and xylan. It is anticipated that these models could be used in process simulations of bioethanol production from lignocellulosic materials. Biotechnol. Bioeng. 2010;105: 88–97. © 2009 Wiley Periodicals, Inc.
Perturbation‐independent community development in low‐temperature anaerobic biological wastewater treatment bioreactors
Authors: Madden Pádhraig , Chinalia Fabio A. , Enright Anne‐Marie , Collins Gavin , O'Flaherty Vincent
Published: August 2009

The reproducibility and stability of low‐ temperature anaerobic wastewater treatment systems undergoing transient perturbations was investigated. Three identical anaerobic expanded granular sludge bed‐based bioreactors were used to degrade a volatile fatty acid and glucose‐based wastewater under sub‐ambient (15°C) conditions. The effect of a variety of environmental perturbations on bioreactor performance was assessed by chemical oxygen demand removal. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes extracted from sludge granules. Methanogenic activity was monitored using specific methanogenic activity assays. Bioreactor performance and microbial population dynamics were each well replicated between both experimental bioreactors and the control bioreactor prior to, and after the implementation of most of the applied perturbations. Gene fingerprinting data indicated that Methanosaeta sp. were the persistent, keystone members of the archaeal community, and likely were pivotal for the physical stability and maintenance of the granular biofilms. Cluster analyses of DGGE data suggested that temporal shifts in microbial community structure were predominantly independent of the applied perturbations. Biotechnol. Bioeng. 2010;105: 79–87. © 2009 Wiley Periodicals, Inc.
Microbial community structure in a biofilm anode fed with a fermentable substrate: The significance of hydrogen scavengers
Authors: Parameswaran Prathap , Zhang Husen , Torres César I. , Rittmann Bruce E. , Krajmalnik‐Brown Rosa
Published: August 2009

We compared the microbial community structures that developed in the biofilm anode of two microbial electrolysis cells fed with ethanol, a fermentable substrate—one where methanogenesis was allowed and another in which it was completely inhibited with 2‐bromoethane sulfonate. We observed a three‐way syntrophy among ethanol fermenters, acetate‐oxidizing anode‐respiring bacteria (ARB), and a H2 scavenger. When methanogenesis was allowed, H2‐oxidizing methanogens were the H2 scavengers, but when methanogenesis was inhibited, homo‐acetogens became a channel for electron flow from H2 to current through acetate. We established the presence of homo‐acetogens by two independent molecular techniques: 16S rRNA gene based pyrosequencing and a clone library from a highly conserved region in the functional gene encoding formyltetrahydrofolate synthetase in homo‐acetogens. Both methods documented the presence of the homo‐acetogenic genus, Acetobacterium, only with methanogenic inhibition. Pyrosequencing also showed a predominance of ethanol‐fermenting bacteria, primarily represented by the genus Pelobacter. The next most abundant group was a diverse community of ARB, and they were followed by H2‐scavenging syntrophic partners that were either H2‐oxidizing methanogens or homo‐acetogens when methanogenesis was suppressed. Thus, the community structure in the biofilm anode and suspension reflected the electron‐flow distribution and H2‐scavenging mechanism. Biotechnol. Bioeng. 2010;105: 69–78. © 2009 Wiley Periodicals, Inc.
PASCAL: physics augmented space canvases for animating locomotion
Authors: Fei Guangzheng , Lee Won‐Sook , Xin Zijun , Dong Huikai , Joslin Chris
Published: August 2009

We describe an animation creation system called PASCAL that supports sketch‐based modeling and physics augmented locomotion simultaneously. The system uses sketches and reconfigurable space canvases as basic modeling primitives and uses physics to improve the expressiveness and efficiency of several animation techniques to obtain controllable and plausible locomotion animation. The usability evaluation of the system was conducted both with professional and novice animators. Copyright © 2009 John Wiley & Sons, Ltd.
Activity‐Based Probes for Monitoring Postproline Protease Activity
Authors: Sabidó Eduard , Tarragó Teresa , Niessen Sherry , Cravatt Benjamin F. , Giralt Ernest
Published: August 2009

Postproline proteases constitute a subset of serine proteases involved in the regulation of many signaling events and are emerging as promising therapeutic targets for prevalent diseases, such as diabetes and cancer. Therefore, monitoring their activity in different tissues and diverse physiological states would certainly facilitate the elucidation of their physiological role and the establishment of new therapeutic targets. Here, we have synthesized a dipeptidyl phosphonate activity‐based probe that has proved to be highly selective for a specific postproline protease, prolyl oligopeptidase (POP). Its high sensitivity allows the detection of the endogenous activity of POP both by in‐gel analysis and mass spectrometry. The evidence provided by mass spectrometry for the high selectivity of the synthesized probe opens the possibility of using dipeptidyl phosphonates not only for activity‐based profiling (ABP), but also for other ABP applications like substrate‐based protease identification.
Potent Inhibition of Acid Sphingomyelinase by Phosphoinositide Analogues
Authors: Roth Anke Gundula , Redmer Susanne , Arenz Christoph
Published: August 2009

The different mammalian sphingomyelinases are involved in cell regulation, apoptosis and inflammatory events. Recent reports suggest pharmacological potential especially for inhibitors of the acid sphingomyelinase. Phosphatidyl inositol‐3,5bisphosphate (PtdIns3,5P2) is the most potent selective acid sphingomyelinase inhibitor known to date. In the present study, we synthesized analogues of PtdIns3,5P2 for initial structure–activity‐relationship (SAR) studies. We identified an inhibitor that is easy to synthesize, that has superior chemical and biophysical properties when compared to PtdIns3,5P2 and that should be stable against virtually all phospholipases. Last but not least, the new inhibitor partially protected cells from dexamethasone‐induced cell death.
Quantitative Use of Paramagnetic Relaxation Enhancements for Determining Orientations and Insertion Depths of Peptides in Micelles
Authors: Franzmann Magnus , Otzen Daniel , Wimmer Reinhard
Published: August 2009

We describe the background and implementation of a method to determine, at atomic resolution, the insertion depths and orientations of peptides embedded in micelles. A nonperturbing paramagnetic agent—Gd(DTPA–BMA)—was used to induce paramagnetic relaxation enhancements (PREs) of peptide atoms inside the micelle. By calibrating these PREs it was possible to translate them into distance restraints that could be used for structure calculation. We demonstrate this here on the antimicrobial peptides novicidin and novispirin. Characterization of the interactions between antimicrobial peptides and membranes is important for understanding of their biological activities and functions, and a further development of tools to study these interactions is described.
The Brain First or the Heart: The Approach to Revascularizing Severe Co‐Existing Carotid and Coronary Artery Disease
Authors: Aqel Raed , Dorfman Todd A.
Published: August 2009

Combined symptomatic severe cerebralvascular disease and significant obstructive coronary artery disease frequently exist.1,2 For the past few decades, clinicians have debated the various treatment strategies for these high‐risk patients including staged procedures and hybrid revascularization. While some recommend addressing the more unstable vascular territory first, others prefer to intervene on the carotids prior to performing coronary revascularization. Both surgical and percutaneous options have been explored in various clinical settings, but there are no treatment guidelines to date. Given the frequency and magnitude of this problem, we performed an extensive review of the literature in an attempt to add some much needed clarity. An illustrative case and recommendations are provided. Copyright © 2009 Wiley Periodicals, Inc.
Extrinsic Compression of Left Main Coronary Artery by the Pulmonary Trunk Secondary to Pulmonary Hypertension Documented Using 64‐Slice Multidetector Computed Tomography Coronary Angiography
Authors: Safi Morteza , Eslami Vahid , Shabestari Abbas Arjmand , Saadat Habib , Namazi Mohammad Hasan , Vakili Hosein , Movahed Mohammad Reza
Published: August 2009

Compression of left main coronary artery (LMCA) secondary to pulmonary trunk dilatation is a newly recognized entity that has been associated with severe pulmonary hypertension. In this paper we present a case of extrinsic compression of LMCA caused by dilated pulmonary trunk secondary to pulmonary hypertension documented using 64‐slice multidetector computed tomography (MDCT) coronary angiography. This case is followed by a review of the literature. Copyright © 2009 Wiley Periodicals, Inc.
Echocardiography for Determining the Optimal Atrioventricular Interval in Patients with Dual Chamber Pacemakers
Authors: Sun Pin , Zhao Qing , Wang Zhi‐Bin , Li Jian‐Sheng , Wo Jin‐Shan , Cai Shang‐Lang
Published: August 2009

Background

We investigated the clinical value of Doppler echocardiography for determining the optimal setting of atrioventricular interval in patients with dual chamber pacemakers (DDD). In 38 patients with complete atrioventricular block and DDD pacemakers, the atrioventricular interval was prolonged in a stepwise fashion by 20 ms, from 90 to 250 ms, and cardiac stroke volume and transmitral flow were measured by pulsed Doppler echocardiography.

Methods

The optimal atrioventricular interval at which the cardiac stroke volume was maximal was 168.9 ± 15.6 ms. The atrioventricular interval was 178.4 ± 23.4 ms when the end of the A wave coincided with complete closure of the mitral valve.

Results

There was a significant linear relationship between the optimal atrioventricular interval and the predicted optimal atrioventricular interval (Y = 86.2 ± 0.5X, r = 0.70, standard error of the estimate [SEE] = 11.5, P < 0.01).

Conclusion

The optimal atrioventricular interval setting for DDD pacing can be successfully determined using Doppler echocardiography, which is a noninvasive, repeatable, and simple approach. Copyright © 2009 Wiley Periodicals, Inc.
N‐Terminal Pro‐B‐Type Natriuretic Peptide and Inducible Ischemia in the Heart and Soul Study
Authors: Singh Harsimran S. , Bibbins‐Domingo Kirsten , Ali Sadia , Wu Alan H. B. , Schiller Nelson B. , Whooley Mary A.
Published: August 2009

Background

B‐type natriuretic peptide (BNP) is predictive of inducible ischemia in patients with coronary heart disease (CHD). Whether N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) has a comparable strength of association with ischemia is uncertain.

Hypothesis

Resting NT‐proBNP levels are associated with inducible ischemia in patients with stable CHD.

Methods

We performed a cross‐sectional study of 901 outpatients with stable CHD. NT‐proBNP was measured in all patients prior to exercise treadmill testing and stress echocardiography. In addition, plasma BNP was measured in a subset of 355 participants. Logistic regression was used to examine the association of NT‐proBNP and BNP quartiles with inducible ischemia.

Results

Inducible ischemia was found in 216 (24%) patients. The proportion with inducible ischemia ranged from 42% (95/225) in the highest quartile of NT‐proBNP levels (>410 pg/ml) to 9% (21/226) in the lowest quartile (0–72 pg/ml). The highest quartile had a 7‐fold greater odds of inducible ischemia than the lowest quartile (odds ratio [OR]: 7.1, 95% confidence interval [CI]: 4.2–12; P < 0.0001). This association remained robust after adjustment for traditional cardiovascular risk factors, left ventricular ejection fraction, and diastolic dysfunction (OR: 3.6, 95% CI: 1.4–9.1; P = 0.009). In the subgroup with measurements of both NT‐proBNP and BNP, both natriuretic peptides were predictive of ischemia. The multivariable‐adjusted c‐statistics for inducible ischemia were 0.71 for NT‐proBNP and 0.62 for BNP (entered as continuous variables).

Conclusions

Resting NT‐proBNP levels are independently associated with inducible ischemia in outpatients with stable CHD. Baseline elevations of natriuretic peptide may indicate subclinical inducible ischemia in high risk patients with CHD. Copyright © 2009 Wiley Periodicals, Inc.