bluuebunny/crossref_metadata_2025 huggingface dataset:
Living cationic polymerization of isobutylene coinitiated by FeCl3 in the presence of isopropanol
Authors: Yan Peng‐Fei , Guo An‐Ru , Liu Qiang , Wu Yi‐Xian
Published: May 2012

A simple but effective FeCl3‐based initiating system has been developed to achieve living cationic polymerization of isobutylene (IB) using di(2‐chloro‐2‐propyl) benzene (DCC) or 1‐chlorine‐2,4,4‐trimethylpentane (TMPCl) as initiators in the presence of isopropanol (iPrOH) at −80 °C for the first time. The polymerization with near 100% of initiation efficiency proceeded rapidly and completed quantitatively within 10 min. Polyisobutylenes (PIBs) with designed number‐average molecular weights (Mn) from 3500 to 21,000 g mol−1, narrow molecular weight distributions (MWD, Mw/Mn ≤ 1.2) and near 100% of tert‐Cl terminal groups could be obtained at appropriate concentrations of iPrOH. Livingness of cationic polymerization of IB was further confirmed by all monomer in technique and incremental monomer addition technique. The kinetic investigation on living cationic polymerization was conducted by real‐time attenuated total reflectance Fourier transform infrared spectroscopy. The apparent constant of rate for propagation (kpA) increased with increasing polymerization temperature and the apparent activation energy (ΔEa) for propagation was determined to be 14.4 kJ mol−1. Furthermore, the triblock copolymers of PS‐b‐PIB‐b‐PS with different chain length of polystyrene (PS) segments could be successfully synthesized via living cationic polymerization with DCC/FeCl3/iPrOH initiating system by sequential monomer addition of IB and styrene at −80 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Tuning h‐bond capability of hydroxylated‐poly(2,3,4,5,6‐pentafluorostyrene) grafted copolymers prepared by chemoselective and versatile thiol‐para‐fluoro “click‐type” coupling with mercaptoalcohols
Authors: Chen Jing , Dumas Ludovic , Duchet‐Rumeau Jannick , Fleury Etienne , Charlot Aurélia , Portinha Daniel
Published: May 2012

Novel H‐bond donor copolymers were designed by a versatile “click type” grafting reaction of unprotected mercaptoalcohols onto poly(2,3,4,5,6‐pentafluorostyrene) (PPFS). As demonstrated by 19F NMR and Fourier transform infrared spectroscopy (FTIR) analyses, the reaction appears to be chemoselective as the SH groups solely react onto the para‐fluoro position of the PFS units. The nucleophilic substitution was successfully performed with two mercaptoalcohols bearing either one or two hydroxyl groups. By carefully selecting the experimental conditions, a library of copolymers with various degree of substitution up to 95% was obtained in a reasonable timescale through kinetic control. By turbidity analysis, the ability of these functional polymers to form in solution interpolymer complexes with poly(4‐vinyl pyridine) was shown to be tunable by adjusting the molecular characteristics. FTIR, X‐ray photoelectron spectroscopy, and Differential scanning calorimetry evidence that different types of blends (immiscible, partially or totally miscible, and complex) can be achieved, and that the driving force of the interaction originates from H‐bond. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Effect of initiation site location on morphology of polymer microspheres via pickering polymerization
Authors: Zhou Yiliang , Zhao Yongliang , Wang Haitao , Du Qiangguo
Published: May 2012

A novel way is introduced to control polymerization routes and morphology of final polymer microspheres during the Pickering polymerization. Cetyltrimethylammonium bromide (CTAB)‐modified silica and different initiators are used simultaneously to determine the initiation location, nucleation step, and morphology of final particles. As Pickering stabilizer, the CTAB‐modified silica is characterized by dynamic light scattering. The size and distribution of the oil droplets stabilized by the silica nanoparticles is observed by optical microscopy. The resulted silica/polymer composite microspheres are characterized by scanning electron microscopy and transmission electron microscopy. The silica content is measured by thermogravimetric analysis. It is proven that both surface property of inorganic particles and type of initiators can greatly affect the polymerization routes and the morphology of the obtained polymer microspheres. Detailed formation mechanisms of several kinds of polymer particles are also proposed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis and properties of novel functional polymers from tetrachlorinated perylene bisimide
Authors: Cui Yi , Yao Dongdong , Chen Yongming , Wang Zhaohui
Published: May 2012

Asymmetric tetrachlorinated perylene‐3,4,9,10‐tetracarboxylic acid bisimides (4Cl‐PBI) were prepared in one‐pot by a reaction of tetrachlorinated perylene‐3,4,9,10‐tetracarboxylic acid dianhydride with a mixture of 2‐aminoethanol and dodecanamine or 2‐decyltetradecan‐1‐amine. Then, two 4Cl‐PBI methacrylates bearing one (M1) and two (M2) long alkyl tails were prepared, and a series of functional homopolymers were obtained by subjecting conventional radical polymerization and atom transfer radical polymerization. Furthermore, amphiphilic block copolymers pendent with 4Cl‐PBI units, PEO‐PM1 and PEO‐PM2, were prepared using monomethoxyl PEO bromoisobutyrate as a macroinitiator. Size exclusion chromatography, UV–vis spectroscopy, fluorescence spectroscopy, and cyclic voltammetry have been applied to characterize the polymers obtained. Moreover, the Ullmann reactions between the grafted 4Cl‐PBI units were conducted to form large π units, and the PEO‐PM2 block copolymers gave di‐ or tri‐PBI units in about 30%. Also, self‐assembly of the amphiphilic block copolymers PEO‐PM1 and PEO‐PM2 in water was applied to generate spherical nanoparticles of 4Cl‐PBI. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Three‐arm star block copolymers of aromatic polyether and polystyrene from chain‐growth condensation polymerization, atom transfer radical polymerization, and click reaction
Authors: Yamazaki Yuka , Yokoyama Akihiro , Yokozawa Tsutomu
Published: May 2012

Well‐defined (AB)3 type star block copolymer consisting of aromatic polyether arms as the A segment and polystyrene (PSt) arms as the B segment was prepared using atom transfer radical polymerization (ATRP), chain‐growth condensation polymerization (CGCP), and click reaction. ATRP of styrene was carried out in the presence of 2,4,6‐tris(bromomethyl)mesitylene as a trifunctional initiator, and then the terminal bromines of the polymer were transformed to azide groups with NaN3. The azide groups were converted to 4‐fluorobenzophenone moieties as CGCP initiator units by click reaction. However, when CGCP was attempted, a small amount of unreacted initiator units remained. Therefore, the azide‐terminated PSt was then used for click reaction with alkyne‐terminated aromatic polyether, obtained by CGCP with an initiator bearing an acetylene unit. Excess alkyne‐terminated aromatic polyether was removed from the crude product by means of preparative high performance liquid chromatography (HPLC) to yield the (AB)3 type star block copolymer (Mn = 9910, Mw/Mn = 1.10). This star block copolymer, which contains aromatic polyether segments with low solubility in the shell unit, exhibited lower solubility than A2B or AB2 type miktoarm star copolymers. In addition, the obtained star block copolymer self‐assembled to form spherical aggregates in solution and plate‐like structures in film. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Influence of multiwall carbon nanotubes on morphological and structural changes during UV irradiation of syndiotactic polypropylene films
Authors: Guadagno L. , Raimondo M. , Naddeo C. , Di Bartolomeo A. , Lafdi K.
Published: May 2012

The effect of UV irradiation on the morphology and structure of syndiotactic polypropylene (sPP) is investigated both for pure films and those filled with multiwall carbon nanotubes (MWCNTs). UV treatment causes a structural reorganization of pure sPP films. It seems that the incorporation of MWCNTs has a strong stabilizing effect, with nanotubes acting as a limiter of the UV‐induced chain breakage, especially when a good dispersion of carbon nanotubes in the polymer is achieved. The incorporation of MWCNTs introduces a high concentration of defects in the crystal structure of sPP, which limits the UV‐induced growth of crystallites, and prevents the development and propagation of cracks caused by UV irradiation. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Fabrication of Ca, Zr doped BaTiO3 ferroelectric nanofibers by electrospinning
Authors: Jalalian Abolfazl , Grishin Alexander M. , Wang Xiaolin , Dou Shi Xue
Published: May 2012

As first time, (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanofibers are synthesized by sol‐gel assisted electrospining technique. Non‐woven and bead‐free BCTZ nanofibers mat was formed and a single chemical phase was achieved after calcination of the nanofibers at 700 °C in air. XRD and Raman spectroscopy show that BCTZ nanofibers crystallized in the morphotropic phase boundary (MPB) region (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In Vitro and In Vivo Aldose Reductase Inhibitory Activity of Standardized Extracts and the Major Constituent of Andrographis paniculata
Authors: Veeresham Ciddi , Swetha Ettireddy , Rao Ajmeera Rama , Asres Kaleab
Published: May 2012

Aldose reductase is the first enzyme in the polyol pathway and catalyzes the reduction of glucose to sorbitol by coupling with the oxidation of NADPH to NADP+. This sorbitol accumulation leads to various diabetic complications, including neuropathy, nephropathy, cataracts, and retinopathy. In the present study, aldose reductase inhibitory (ARI) activity of the methanolic as well as standardized extracts of Andrographis paniculata (Burm. f.) Wall. ex Nees (Acanthaceae) and its chief constituent, andrographolide, were studied using in vitro and in vivo methods. In the in vitro method, rat lens as well as kidney homogenates were used for the preparation of enzyme, whereas the effect of these test samples on the galactitol level in the eye lens was studied in a galactosemic rat model in vivo. The results of the study revealed that both extracts of the plant and its major compound, andrographolide, possess ARI activity in vitro. They were also found to significantly decrease galactitol accumulation in vivo. Copyright © 2012 John Wiley & Sons, Ltd.
Hepatoprotection of Berberine Against Hydrogen Peroxide‐induced Apoptosis by Upregulation of Sirtuin 1
Authors: Zhu Xiaofei , Guo Xiaofang , Mao Genxiang , Gao Zhitao , Wang Hui , He Qiyang , Li Diandong
Published: May 2012

Berberine (BBR) has been suggested to be a hepatoprotective agent for oxidative‐stress‐related liver diseases because of its antioxidant activity. However, the antioxidant mechanisms of BBR are still not fully understood. In the present study, the protective effect of BBR was evaluated, and the underlying molecular mechanisms were investigated in hepatic cell line L02. Results from cell viability and apoptosis assay showed that in cells exposed to hydrogen peroxide (H2O2), the pretreatment of 12 μM BBR could increase cell viability by 19.10 ± 7.40% and reduce apoptotic cells by 7.91 ± 0.78%. A significant change in the expression levels of sirtuin 1 (SIRT1) and apoptosis‐related proteins was also observed in the BBR‐pretreated hepatocytes under exposure to H2O2. Furthermore, BBR exhibited a time‐dependent effect on upregulation of SIRT1 in L02 cells. This study demonstrated that the protective effect of BBR against H2O2‐induced apoptosis was associated with regulation of SIRT1 in hepatic cell line L02, which provided a possible explanation for its antioxidant activity, and implied an application of BBR for the therapeutic relevance in oxidative‐stress‐related liver diseases. Copyright © 2012 John Wiley & Sons, Ltd.
Cytotoxic Activity and Antioxidant Capacity of Purified Lichen Metabolites: An In Vitro Study
Authors: Brisdelli Fabrizia , Perilli Mariagrazia , Sellitri Doriana , Piovano Marisa , Garbarino Juan A. , Nicoletti Marcello , Bozzi Argante , Amicosante Gianfranco , Celenza Giuseppe
Published: May 2012

The purpose of this study was to investigate the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on proliferation, viability and reactive oxygen species (ROS) level towards three human cancer cell lines, MCF‐7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT‐116 (colon carcinoma). Cells were treated with different concentrations (2.5–100 μM) of these compounds for 48 h. In this comparative study, our lichen metabolites showed various cytotoxic effects in a concentration‐dependent manner, and usnic acid was the most potent cytotoxic agent, while variolaric acid did not inhibit the proliferation of any of the three cell lines used. All tested lichen compounds did not exhibit free radical scavenging activity using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assay. The lichen metabolites did not significantly increase the intracellular ROS level and did not prevent oxidative injury induced by t‐butylhydroperoxide in HeLa cells. To better clarify the mechanism(s) of cytotoxic effect induced by protolichesterinic acid in HeLa cells, we investigated apoptotic markers such as condensation and fragmentation of nuclear chromatin and activation of caspase‐3, 8 and 9. Our results revealed that the antiproliferative activity of 40 μM protolichesterinic acid in HeLa cells is related to its ability to induce programmed cell death involving caspase‐3, 8 and 9 activation. Copyright © 2012 John Wiley & Sons, Ltd.
Ethanol Extract of Magnolia officinalis Prevents Lipopolysaccharide‐Induced Memory Deficiency via Its Antineuroinflammatory and Antiamyloidogenic Effects
Authors: Lee Young‐Jung , Choi Dong‐Young , Yun Yeo‐Pyo , Han Sang Bae , Kim Hwan Mook , Lee Kiho , Choi Seok Hwa , Yang Mhan‐Pyo , Jeon Hyun Soo , Jeong Jea‐Hwang , Oh Ki‐Wan , Hong Jin Tae
Published: May 2012

Magnolia bark contains several compounds such as magnolol, honokiol, 4‐O‐methylhonokiol, obovatol, and other neolignan compounds. These compounds have been reported to have various beneficial effects in various diseases. There is sufficient possibility that ethanol extract of Magnolia officinalis is more effective in amyloidogenesis via synergism of these ingredients. Neuroinflammation has been known to play a critical role in the pathogenesis of Alzheimer's disease (AD). We investigated whether the ethanol extract of M. officinalis (10 mg/ kg in 0.05% ethanol) prevents memory dysfunction and amyloidogenesis in AD mouse model by intraperitoneal lipopolysaccharide (LPS, 250 µg/ kg/day for seven times) injection. We found that ethanol extract of M. officinalis prevented LPS‐induced memory deficiency as well as inhibited the LPS‐induced elevation of inflammatory proteins, such as inducible nitric oxide synthase and cyclooxygenase 2, and activation of astrocytes and microglia. In particular, administration of M. officinalis ethanol extract inhibited LPS‐induced amyloidogenesis, which resulted in the inhibition of amyloid precursor protein, beta‐site amyloid‐precursor‐protein‐cleaving enzyme 1 and C99. Thus, this study shows that ethanol extract of M. officinalis prevents LPS‐induced memory impairment as well as amyloidogenesis via inhibition of neuroinflammation and suggests that ethanol extract of M. officinalis might be a useful intervention for neuroinflammation‐associated diseases such as AD. Copyright © 2012 John Wiley & Sons, Ltd.
Stabilization of linear systems with time‐varying delays
Authors: Wang Guoliang , Zhang Qingling
Published: May 2012

This paper is concerned with the stability and stabilization problems for a class of time‐delayed systems, whose time‐varying delays are studied via Markovian approach. By separating the delay interval into several subintervals and by considering the inherent distribution of time‐varying delay, a new model is firstly developed. On the basis of the established model, a novel Lyapunov functional, which makes full use of each subinterval's delay bounds and the randomicity of time‐varying delay, is constructed to drive less conservative stability criteria. Especially sufficient conditions for the existence of stabilizing controllers are obtained as linear matrix inequalities, which are further used to deal with networked control systems. Finally, numerical examples are used to demonstrate the effectiveness of the proposed methods. Copyright © 2012 John Wiley & Sons, Ltd.
NATURAL FLOW REGIME CLASSIFICATIONS ARE SENSITIVE TO DEFINITION PROCEDURES
Authors: Snelder T. H. , J. Booker D.
Published: May 2012

The correspondence and performance of six classifications of flow regimes of New Zealand rivers that were all mapped onto the same digital river network were assessed. Classification 1 was defined deductively, based on expert‐defined rules. Classifications 2 to 6 were defined inductively using hydrological indices calculated from 321 natural daily flow records. Classifications 2 to 4 were defined by first clustering the gauges based on the hydrological indices and then predicting the class of each segment of the network using a Random Forest classifier. Classifications 5 and 6 were defined by first predicting the indices for each segment of the network using Random Forest regression models. Cluster analysis was then used to group the network segments into classes. Further differences between classifications were due to differences in the standardisation of the hydrological indices and clustering algorithms. Correspondence (extent to which the patterns defined by the classifications were similar) was assessed formally using the adjusted Rand index and visually. The performance of the classifications was assessed using classification strength calculated using the hydrological indices and ANOVA calculated for individual indices. Correspondence between the classifications was low (adjusted Rand index range, 0.1–0.5). Classification strength and ANOVA statistics assessed using cross validation indicated that the inductive classifications performed better than the deductively defined classification and that there were some significant differences in performance between the inductive classifications. However, these differences were not large from a practical point of view. Our results indicate that there are many credible classifications of the flow regimes of a study region. When considering methods for defining flow regime classifications, aspects other than the predictive performance, such as flow data requirements and how easily the final classification can be explained, should be considered. Copyright © 2012 John Wiley & Sons, Ltd.
Gekrümmte Isoliergläser
Authors: Neugebauer Jürgen
Published: May 2012

In der Architektur ist eine Tendenz zu erkennen, die zeigt, dass immer mehr gekrümmte Isoliergläser geplant sowie eingebaut werden. Im Vergleich zu flachen Gläsern treten hier Unterschiede in der Lastabtragung bzw. in der Bemessung auf. Die Krümmungen solcher Gläser haben einen direkten Einfluss auf den effektiven Innendruck sowie auf den so genannten Koppeleffekt für externe Lasten wie z.B. den Wind. Des Weiteren sollten Einflüsse wie z.B. der des Randverbundes nicht mehr wie bei den flachen Isoliergläsern vernachlässigt werden. Mit der Definition eines isochoren und isobaren Limits für die Druckverhältnisse im Scheibenzwischenraum können solche Bemessungen von Isoliergläsern mit den unterschiedlichsten Formen durchgeführt werden.
Kalt‐Bemessung von Brandschutzverglasungen und Klassifizierung des Brandverhaltens
Authors: Hoegner Hermann
Published: May 2012

Wer sich als Planer mit einer Brandschutzverglasung befasst, legt seiner Arbeit üblicherweise eine Allgemeine Bauaufsichtliche Zulassung zugrunde, wovon es auch eine große Anzahl gibt. Glasarten, Scheibenaufbauten, Scheibengrößen und die zu verwendenden Profile, Leisten, Schrauben, Dichtungsmittel, usw. werden der Zulassung unmittelbar entnommen. Weitergehende Betrachtungen zur statisch‐konstruktiven Bemessung werden normalerweise nicht angestellt. In der Vergangenheit war es üblich, auch die Kalt‐Bemessung von Brandschutzverglasungen in den Allgemeinen Bauaufsichtlichen Zulassungen abschließend mit zu regeln. Wegen der Ausweitung des Anwendungsbereiches solcher Feuerschutzabschlüsse wird das zukünftig jedoch nicht mehr so sein. Genau genommen ist es schon jetzt nicht mehr so. Worauf in Abhängigkeit von der jeweiligen Situation bei der Bemessung feuerwiderstandsfähiger Verglasungen nunmehr besonders zu achten ist, wird nachfolgend erläutert. Daneben wird auch das problematische Thema Brandverhaltensklassifizierung von Verbundglas als Baustoff angesprochen.
VSG‐Glasstützen unter kombinierter Langzeit‐ und Kurzzeitbelastung
Authors: Langosch Katharina , Feldmann Markus
Published: May 2012

Zur Erhöhung der Gebäudetransparenz werden tragende Elemente aus Glas, wie z.B. Stützen, mit Verbundquerschnitten eingesetzt. Die Ausführungen solcher stabilitätsgefährdeter Ganzglaskonstruktionen verlangt nach geeigneten Bemessungsregeln, welche sowohl das Werkstoffverhalten von Glas als auch die Materialeigenschaften der Zwischenschicht berücksichtigen. Basierend auf den bereits in früheren Ausgaben der Stahlbau‐Spezial‐Reihe “Glasbau“ vorgestellten Grundlagen, werden in dem vorliegenden Artikel Knickkurven für VSG‐Stützen nach dem europäischem Format vorgestellt, welche die Verbundwirkung der Zwischenschicht erfassen. Weiter wird beschrieben, wie die Effekte aus kombinierter Lang‐ und Kurzzeitbelastung berücksichtigt werden können.
Glashäuser – warum nicht mehr ausführbar wie vor 150 Jahren?
Authors: Techen Holger , Michel Matthias
Published: May 2012

Regeln der Technik und Normen dienen heute als Bemessungsgrundlage für den Einsatz von Glas als Konstruktionswerkstoff und gewährleisten damit, dass der spröde Werkstoff Glas mit einem für andere Baustoffe vergleichbaren Sicherheitsniveau bemessen werden kann. Ergänzt durch aktuelle Forschungsergebnisse, wie auch hier veröffentlicht, sind Anwendungen von Glas als Konstruktionswerkstoff umsetzbar, die an die Leichtigkeit der Konstruktion, für die z.B. die Gewächshäuser des 19. Jahrhunderts berühmt waren, wieder anknüpft. Über den Ansatz der Detaillierung bei Fügung und Profil werden zwei Projekte vorgestellt, die in engster Zusammenarbeit zwischen Architekt, Ingenieur und ausführender Firma entstanden. Dabei wurde der Einsatz von Glas als Konstruktionswerkstoff nicht nur im Hinblick auf seine statische Beanspruchbarkeit, sondern auch glasspezifische Fügetechniken weiter entwickelt.
Die Zukunft energieaktiver und adaptiver Gebäudehüllen
Authors: Fuchs Andreas
Published: May 2012

Das 2° System und das nach DGNB vorzertifizierte und mit Gold bewertete Energy3 Building sind die aktuellen Ergebnisse einer langjährigen Zusammenarbeit in Forschung und Entwicklung mit der Firma SCHÜCO, der führende Hersteller für Fassadensysteme und Gebäudehüllkomponenten. Der realisierte Prototyp für die BAU 2011 belegt sowohl das energetische, als auch das formale Potential integrierter und energieaktiver Funktionsschichten in der Gebäudehülle. Darüber hinaus reagieren diese Funktionsschichten adaptiv auf wechselnde klimatische und nutzungsbedingte Einflüsse. Energetische Werte, bisher als statische Größen definiert, passen sich nun den Anforderungen der Umwelt an und stellen damit optimierte Lösungen für die jeweilige Aufgabe dar.
Tragfähigkeit von Dünnschicht‐Photovoltaik‐Modulen
Authors: Schneider Jens , Kleuderlein Jonas , Kuntsche Johannes
Published: May 2012

Die steigende Verwendung von Dünnschicht‐PV‐Modulen und das Aufkommen von Schäden wirft die Frage nach einem ausreichenden Sicherheitsniveau für die Tragfähigkeit der derzeit eingesetzten Glas‐Glas‐Module auf. Der Beitrag vergleicht die in der Solarbranche übliche experimentelle Ermittlung der Tragfähigkeit nach DIN EN 61646 und die rechnerischen Nachweisen nach den im Glasbau aktuellen Bemessungsregelwerken (TRLV, DIN 18008). Es werden erhebliche Unterschiede im Sicherheitsniveau aufgezeigt.
Structural‐Glazing‐Fassade für die Zeppelin‐University Friedrichshafen
Authors: Burmeister Albrecht , Eitel Lutz
Published: May 2012

Um für die Zeppelin‐University in Friedrichshafen die gestalterischen Anforderungen einer hochtransparenten und innovativen Fassadenlösung zu erfüllen, wurde eine Structural‐Glazing‐Fassade in Verbindung mit extrem leichten Aluminium‐Strangpress‐Profilen entwickelt. Dadurch kommt es zu einem gekoppelten Verhalten von Tragprofilen, Glas und Verklebung, welche mit adäquaten finite Element‐basierten Analysen berücksichtigt wurden. Die Realisierung der Absturzsicherungsfunktion über die Verglasung und deren Verklebung zusammen mit dem Verzicht auf mechanische Halteelemente und der Ansatz von Schubverbund über die PVB‐Folie unterstreichen den innovativen Ansatz.
Shuter Street Bridge, Toronto – Fußgängerbrücke mit gebogenen Isoliergläsern
Authors: Schmitt Felix , Sendelbach Michael , Elbert Harald , Benning Matthias , Wellershoff Frank
Published: May 2012

Eine über 30 Meter lange gläserne Fußgängerbrücke mit einer Tragstruktur aus gebogenen Stahlrohren erstreckt sich über die Shuter Street im kanadischen Toronto. Ovale Stahlringe sind jeweils verdreht zueinander angeordnet und mit gebogenen Isoliergläsern verglast. Mit der neuen Brücke hat das Architekturbüro Diamond and Schmitt Architects Inc. aus Toronto eine witterungsunabhängige Verbindung zwischen dem St. Michael´s Hospital und dem neuen Forschungszentrum Li Ka Shing Knowledge Institute geschaffen. Die optisch ansprechende Fußgängerbrücke hat eine Höhe von 4,60m und eine Breite von 3,80m. Da in Toronto das unterirdische Fußgängerwegesystem PATH vorrangig genutzt wird, konnte die Stadt nur durch die architektonische Originalität der Brücke zur Genehmigung bewegt werden. Gebogene, thermisch vorgespannte Isolierglasscheiben geben der Tragstruktur aus sich kreuzenden gebogenen Rohren seine Leichtigkeit und bieten aus jeder Ansicht heraus ein anderes Erscheinungsbild.
DIN 18008 Teile 1‐5: Neuerungen gegenüber eingeführten Regelungen
Authors: Siebert Geralt
Published: May 2012

Nach Veröffentlichung der Endfassung für DIN 18008 Teil 1und 2 im Dezember 2010 wurde mit Datum Oktober 2011 die Entwurfsfassung für Teile 3, 4 und 5 veröffentlicht. Damit sind für die Mehrzahl der Anwendungen nunmehr Regelungen nach dem Konzept der Teilsicherheitsbeiwerte vorhanden. Diese gehen sowohl hinsichtlich Regelungsumfang wie ‐tiefe über die aktuell eingeführten TRXV hinaus.
Low entanglement wavefunctions
Authors: Chan Garnet Kin‐Lic
Published: May 2012

We review a class of efficient wavefunction approximations that are based around the limit of low entanglement. These wavefunctions, which go by such names as matrix product states and tensor network states, occupy a different region of Hilbert space from wavefunctions built around the Hartree–Fock limit. The best known class of low entanglement wavefunctions, the matrix product states, forms the variational space of the density matrix renormalization group algorithm. Because of their different structure to many other quantum chemistry wavefunctions, low entanglement approximations hold promise for problems conventionally considered hard in quantum chemistry, and in particular problems which have a multireference or strong correlation nature. In this review, we describe low entanglement wavefunctions at an introductory level, focusing on the main theoretical ideas. Topics covered include the theory of efficient wavefunction approximations, entanglement, matrix product states, and tensor network states including the tree tensor network, projected entangled pair states, and the multiscale entanglement renormalization ansatz. © 2012 John Wiley & Sons, Ltd.

This article is categorized under:

Electronic Structure Theory > Ab Initio Electronic Structure Methods
The Sonic hedgehog gradient in the developing limb
Authors: Tickle Cheryll , Barker Heather
Published: May 2012

A gradient of Sonic hedgehog (Shh) plays a major role in specifying the antero‐posterior pattern of structures that develop in the distal part of the vertebrate limb, in particular, the antero‐posterior pattern of the digits. Classical embryological experiments identified the polarizing region (or zone of polarizing activity, ZPA), a signaling region at the posterior margin of the early chick wing bud and, consistent with a model in which production of a diffusible morphogen specifies antero‐posterior positional information, polarizing region signaling was shown to be dose dependent and long range. It is now well established that the vertebrate hedgehog gene, Sonic hedgehog (Shh), which encodes a secreted protein, is expressed in the polarizing region of the chick wing and that Shh signaling has the same characteristics as polarizing region signaling. Shh expression at the posterior of the early limb bud and the mechanism of Shh signal transduction are conserved among vertebrates including mammals. However, it is unlikely that a simple Shh gradient is responsible for digit pattern formation in mammalian limbs and there is still little understanding of how positional information specified by Shh signaling is encoded and translated into digit anatomy. Alterations in Shh signaling underlie some congenital limb abnormalities and also changes in timing and extent of Shh signaling appear to be related to the evolution of morphological diversity of vertebrate limbs. WIREs Dev Biol 2013, 2:275–290. doi: 10.1002/wdev.70

This article is categorized under:

Establishment of Spatial and Temporal Patterns > Gradients

Vertebrate Organogenesis > Musculoskeletal and Vascular
Module‐based complexity formation: periodic patterning in feathers and hairs
Authors: Chuong Cheng‐Ming , Yeh Chao‐Yuan , Ting‐Xin Jiang , Widelitz Randall
Published: May 2012

Patterns describe order which emerges from homogeneity. Complex patterns on the integument are striking because of their visibility throughout an organism's lifespan. Periodic patterning is an effective design because the ensemble of hair or feather follicles (modules) allows the generation of complexity, including regional variations and cyclic regeneration, giving the skin appendages a new lease on life. Spatial patterns include the arrangements of feathers and hairs in specific number, size, and spacing. We explore how a field of equivalent progenitor cells can generate periodically arranged modules based on genetic information, physical–chemical rules and developmental timing. Reconstitution experiments suggest a competitive equilibrium regulated by activators/inhibitors involving Turing reaction‐diffusion. Temporal patterns result from oscillating stem cell activities within each module (microenvironment regulation), reflected as growth (anagen) and resting (telogen) phases during the cycling of feather and hair follicles. Stimulating modules with activators initiates the spread of regenerative hair waves, while global inhibitors outside each module (macroenvironment) prevent this. Different wave patterns can be simulated by cellular automata principles. Hormonal status and seasonal changes can modulate appendage phenotypes, leading to ‘organ metamorphosis’, with multiple ectodermal organ phenotypes generated from the same precursors. We discuss potential novel evolutionary steps using this module‐based complexity in several amniote integument organs, exemplified by the spectacular peacock feather pattern. We thus explore the application of the acquired knowledge of patterning in tissue engineering. New hair follicles can be generated after wounding. Hairs and feathers can be reconstituted through self‐organization of dissociated progenitor cells. WIREs Dev Biol 2013, 2:97–112. doi: 10.1002/wdev.74

This article is categorized under:

Establishment of Spatial and Temporal Patterns > Repeating Patterns and Lateral Inhibition

Establishment of Spatial and Temporal Patterns > Cell Sorting and Boundary Formation

Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing
Inhalation studies for the safety assessment of nanomaterials: status quo and the way forward
Authors: Landsiedel Robert , Ma‐Hock Lan , Haussmann Hans‐Juergen , van Ravenzwaay Ben , Kayser Martin , Wiench Karin
Published: May 2012

While technical and medical potential offered by nanotechnologies increase, the safety assessment of engineered nanomaterials (NMs) needs to follow this pace. Inhalation is a major route of occupational and environmental exposure, and is most relevant for most of the respective safety assessment studies. Control and generation of aerosol from the test materials for this route of administration are technically demanding, and not surprisingly, there are relatively few NMs tested in toxicokinetic, short‐term, and subchronic inhalation studies. These studies were in part adapted to the peculiarities of inhaled NMs, but few were also conducted according to organization for economic co‐operation and development (OECD) test guidelines. Inhalation studies on the potential to develop chronic diseases, or studies to check the potential analogy to cardiovascular diseases associated with adverse health effects from ambient air pollution, are largely missing. On the way forward, appropriate inhalation studies need to be performed on a number of NMs to assess their hazards and to provide a sound database for correlation and validation of alternative in vitro methods. Moreover, these studies can potentially aid in the grouping of different NMs based on their biokinetics or biological effects. For carcinogenic and cardiovascular effects, research studies are needed to verify—or disprove—the relevance and the mechanisms by which NMs contribute to these effects. WIREs Nanomed Nanobiotechnol 2012, 4:399–413. doi: 10.1002/wnan.1173

This article is categorized under:

Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials
Tissue Banking in a Regional Hospital: A Promising Future Concept? First Report on Fresh Frozen Tissue Banking in a Hospital Without an Integrated Institute of Pathology
Authors: von Strauss und Torney Marco , Güller Ulrich , Rezaeian Farid , Brosi Philippe , Terracciano Luigi , Zuber Markus
Published: May 2012

Background

Vital tissue provided by fresh frozen tissue banking is often required for genetic tumor profiling and tailored therapies. However, the potential patient benefits of fresh frozen tissue banking are currently limited to university hospitals. The objective of the present pilot study—the first one in the literature—was to evaluate whether fresh frozen tissue banking is feasible in a regional hospital without an integrated institute of pathology.

Methods

Patients with resectable breast and colon cancer were included in this prospective study. Both malignant and healthy tissue were sampled using isopentan‐based snap‐freezing 1 h after tumor resection and stored at −80 °C before transfer to the main tissue bank of a University institute of pathology.

Results

The initial costs to set up tissue banking were 35,662 US$. Furthermore, the running costs are 1,250 US$ yearly. During the first 13 months, 43 samples (nine samples of breast cancer and 34 samples of colon cancer) were collected from 41 patients. Based on the pathology reports, there was no interference with standard histopathologic analyses due to the sample collection.

Conclusions

This is the first report in the literature providing evidence that tissue banking in a regional hospital without an integrated institute of pathology is feasible. The interesting findings of the present pilot study must be confirmed by larger investigations.
Evaluating New York City's Smoke‐Free Parks and Beaches Law: A Critical Multiplist Approach to Assessing Behavioral Impact
Authors: Johns Michael , Coady Micaela H. , Chan Christina A. , Farley Shannon M. , Kansagra Susan M.
Published: May 2012

This article describes the evaluation of the law banning smoking in New York City's parks and beaches that went into effect in 2011. We discuss the practical and methodological challenges that emerged in evaluating this law, and describe how we applied the principles of critical multiplism to address these issues. The evaluation uses data from three complementary studies, each with a unique set of strengths and weaknesses that can provide converging evidence for the effectiveness of the law. Results from a litter audit and an observational study suggest the ban reduced smoking in parks and beaches. The purpose, methodology and baseline results from an ongoing survey that measures how frequently adults in NYC and across New York State notice people smoking in parks and on beaches are presented and discussed. Limitations are considered and suggestions are offered for future evaluations of similar policies.
CYP2D6 genotyping and use of antidepressants in breast cancer patients: test development for clinical application
Authors: van der Merwe Nicole , Bouwens Christianne S. H. , Pienaar Rika , van der Merwe Lize , Yako Yandiswa Y. , Geiger Dieter H. , Kotze Maritha J.
Published: May 2012

Approximately 25 % of clinically important drugs and numerous environmental carcinogens are metabolised by CYP2D6. Variation in the CYP2D6 gene and concomitant use of tamoxifen (TAM) with certain antidepressants may increase recurrence risk in breast cancer patients due to reduced enzyme activity. In this study we determined the appropriateness of adding CYP2D6 genotyping to the breast cancer genetic testing options already available in South Africa, which include BRCA mutation screening and transcriptional profiling to assess estrogen receptor (ER) status. A total of 114 South African breast cancer patients, including 52 Caucasian and 62 Coloured (Mixed ancestry), and 63 Caucasian control individuals were genotyped for the most common inactivating allele (CYP2D6*4, rs3892097) previously identified in the CYP2D6 gene. In the initial validation data set consisting of 25 Caucasian and 62 Coloured patients, the CYP2D6*4 allele frequency was significantly higher in Caucasian compared to Coloured patients (24 % vs. 3 %, p < 0.001), similar to previous findings in the general South African population. Extended CYP2D6 genotyping was subsequently performed in an implementation data set of 27 Caucasian breast cancer patients, to determine the prevalence of depression and use of antidepressants in a clinical setting. A medical history of depression and/or use of antidepressants was reported in 37 % (10/27) of these breast cancer patients genotyped for CYP2D6*4. This translational research study has led to increased awareness among clinicians of the potential benefits of CYP2D6 genotyping to facilitate prevention of cumulative risk in a high-risk genetic subgroup of breast cancer patients considered for concomitant treatment of TAM and antidepressants that may reduce enzyme function.
Functional Extended Redundancy Analysis
Authors: Hwang Heungsun , Suk Hye Won , Lee Jang-Han , Moskowitz D. S. , Lim Jooseop
Published: May 2012

We propose a functional version of extended redundancy analysis that examines directional relationships among several sets of multivariate variables. As in extended redundancy analysis, the proposed method posits that a weighed composite of each set of exogenous variables influences a set of endogenous variables. It further considers endogenous and/or exogenous variables functional, varying over time, space, or other continua. Computationally, the method reduces to minimizing a penalized least-squares criterion through the adoption of a basis function expansion approach to approximating functions. We develop an alternating regularized least-squares algorithm to minimize this criterion. We apply the proposed method to real datasets to illustrate the empirical feasibility of the proposed method.
Tissue Plasminogen Activator Induced Delayed Edema in Experimental Porcine Intracranial Hemorrhage: Reduction with Plasminogen Activator Inhibitor-1 Administration
Authors: Keric Naureen , Maier Gerrit Steffen , Samadani Uzma , Kallenberg Kai , Dechent Peter , Brueck Wolfgang , Heuer Jan , Rohde Veit
Published: May 2012

Hematoma puncture and subsequent clot lysis with recombinant tissue plasminogen activator (rtPA) emerged as an alternative therapy for spontaneous intracerebral hemorrhage (ICH) and is associated with delayed edema possibly counteracting the beneficial effects of hematoma volume reduction. We hypothesized that immediate reversal of rtPA activity after clot lysis and hematoma drainage diminishes edema formation. To test this hypothesis, we administered plasminogen activator inhibitor (PAI)-1 after rtPA lysis of experimentally induced ICH. A right frontal ICH was placed through a twist drill burr hole and autologous blood injection. Following creation of the frontal ICH, pigs received no further treatment (n = 5), lysis with rtPA (n = 7), or lysis with rtPA followed by administration of PAI-1 (n = 6). Hematoma and edema volumes were assessed with magnetic resonance imaging on days 0, 4, and 10. The rtPA significantly reduced hematoma volume and contributed to edema on day 10 after experimentally induced ICH. Administration of PAI-1 attenuated the rtPA-induced edema volume on day 10, but the hematoma volume reduction was less pronounced. In conclusion, PAI-1 attenuated delayed cerebral edema after rtPA lysis of experimental ICH but also reduced the lytic activity of rtPA. The combination of rtPA clot lysis with PAI-1 might have the potential to further improve the effect of the lytic therapy of ICH, but additional studies to define the optimum time point for PAI-1 administration are required.
Informed Consent: A Study of the OR Consenting Process in New Zealand
Authors: Agnew Joanne , Jorgensen Diane
Published: May 2012

The outcome of the informed consenting process should be that patients are knowledgeable about their future procedure, but there is no guarantee that signing the informed consent form means that patients have understood the information that their health care providers have given to them. To evaluate the informed consenting process in an OR direct admissions department of a city hospital in New Zealand, we interviewed 18 surgical patients. We transcribed the audiotaped interviews and analyzed the data using a general inductive approach derived from Grounded Theory. Our analysis indicated that educational information was not always based on patients' previous knowledge or understanding, although most patients understood the surgical consenting process to be complete after they met with the physician and signed the form. Our study highlights that although patients spoke with their physicians and nurses, there was still a lack of understanding. Perioperative nurses are in a prime position to reinforce informed consent. They should actively support the consenting process and be proactive in collaborating with patients and physicians to ultimately ensure that the patient has every opportunity to make an informed decision.
Impact of epistasis and QTL×environmental interaction on the mass filling rate during seed development of soybean
Authors: JIANG ZHENFENG , HAN YINGPENG , TENG WEILI , LI YONGGUANG , ZHAO XUE , ZHANG ZHONGCHEN , MAN WEIQUN , LI WENBIN
Published: May 2012

Seed filling rate of soybean has been shown to be a dynamic process in different developmental stages affected by both genotype and environment. The objective of the present study was to determine additive, epistatic and quantitative trait loci (QTLs)×environment interaction (QE) effects of the QTL underlying a seed filling rate of soybean. One hundred and forty-three recombinant inbred lines (RILs) derived from the cross of Charleston and Dongnong 594 were used with 2 years of field data (2004 and 2005). Eleven QTLs with significantly unconditional and conditional additive (a) effect and/or additive×environment interaction (ae) effect at different filling stages were identified. Of them six QTLs showed positiveaeffects and four QTLs had negativeaeffects on the seed filling rate during seed development.aaandaaeeffects of 12 pairs of QTLs were identified by unconditional mapping from the initial stage to the final stage. Thirteen pairs of QTLs underlying the seed filling rate withaaandaaeeffects were identified by conditional mapping. QTLs withaaandaae(additive×additive×environment) effects appeared to vary at different filling stages. Our results demonstrated that the mass filling rate in soybean seed were under genetic and environmental control.
Struma ovarii and the thyroid surgeon
Authors: Gunasekaran S , Kopecka E , Maung K H , England R J
Published: May 2012

Introduction:

Struma ovarii is a rare, monodermal, ovarian teratoma. The common presentation is abdominal, with pelvic mass and pain, traditionally managed by gynaecologists. The malignant form is extremely rare and consists of differentiated thyroid cancer. It is rare for struma ovarii to present with features of hyperthyroidism. We present two unusual cases of struma ovarii and discuss the role of the thyroid surgeon in their management.

Methods and results:

The first case involved a 40-year-old woman with a two-month history of swelling in the lower abdomen. Investigations revealed a mass arising from the left ovary. Surgery revealed a follicular carcinoma arising in a struma ovarii. She underwent a total thyroidectomy prior to radio-iodine therapy. The second case involved a 60-year-old woman who underwent thyroidectomy for thyrotoxicosis. Three months post-operatively, she remained thyrotoxic despite stopping thyroxine. A whole body radio-iodine scan revealed high uptake in the left ovary. Histological analysis of the resected ovary showed benign struma ovarii.

Conclusion:

These two cases highlight the diagnostic and therapeutic role of thyroid surgeons in the management of benign and malignant forms of struma ovarii.
Submucosal neoplasms of the laryngeal introitus
Authors: Friedman A D , Burns J A , Lutch M J , Zeitels S M
Published: May 2012

Background:

The differential diagnosis of endolaryngeal mesenchymal neoplasms includes a wide spectrum of benign and malignant pathologies, which have been rarely photo-documented and assessed as a group.

Methods:

Non-epithelial neoplasms of the endolarynx seen at our centre from 2002 to 2011 (n = 38; 36 treated at our institution) were retrospectively reviewed, with attention to clinical presentation, radiographic imaging, operative management, histology, and pre- and post-operative endoscopy. Submucosal squamous cell carcinomas, mucosal cysts, amyloid and Teflon granulomas were excluded.

Results:

Twenty-three of a total of 36 patients underwent definitive endoscopic surgical treatment. Supraglottic pathologies included lymphoma, lipoma, neuroendocrine carcinoma, lymphangioma, oncocytoma, haemangioma, synovial cell sarcoma and benign spindle cell neoplasm. Transglottic pathologies included synovial cell sarcoma and granular cell tumour. Glottic pathologies included granular cell tumour, osteoma, rhabdomyoma, rhabdomycosarcoma and myofibroblastic sarcoma. Subglottic pathologies included chondrosarcoma, neurofibroma, adenoid cystic carcinoma and vascular malformation.

Conclusion:

The site of origin, degree of malignant behaviour and sensitivity to adjuvant treatment determined the course of surgical management, i.e. endolaryngeal versus transcervical, and limited removal versus wider resection.