bluuebunny/crossref_metadata_2025 huggingface dataset:
Microstructure and thermal behavior of polylactide/clay nanocomposites melt compounded under supercritical CO2
Authors: Jiang Guo , Huang Han‐Xiong , Chen Zhao‐Ke
Published: August 2011

Supercritical carbon dioxide (Sc‐CO2) is a good plasticizer to improve the compatibility for nanocomposites or polymer blends. In this work, polylactide (PLA)/clay nanocomposites were compounded using a twin‐screw extruder. Two extrusion methods were used, one with Sc‐CO2 and another without Sc‐CO2. Microstructures of nanocomposites and their mechanical properties were investigated. Their thermal behavior was analyzed using differential scanning calorimeter (DSC) and thermogravimetry analyzer. Results show that the layer spacing of clay in the nanocomposites was improved. Observed from transmission electron microscopy photomicrographs, it was shown that the clay was dispersed more homogeneously in the nanocomposites compounded with Sc‐CO2. DSC traces show that cold crystallization appeared for nanocomposites, indicating that clay could act as a nucleating agent. Sc‐CO2 was helpful in improving the thermal stability of nanocomposites. In addition, there existed a yielding phenomenon for nanocomposites during the tensile property measurement. With the preparation of Sc‐CO2, the elongation at break and tensile strength for nanocomposites were increased. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 174–182, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20214
Properties of natural rubber filled with ultrafine carboxylic acrylonitrile butadiene rubber powder
Authors: Sae‐oui Pongdhorn , Sirisinha Chakrit , Intiya Weenusarin , Thaptong Puchong
Published: August 2011

Influence of ultrafine carboxylic acrylonitrile butadiene rubber powder (XNBRP) on properties of natural rubber (NR) was investigated. Mechanical properties, thermal resistance, and oil resistance of XNBRP‐filled NR were determined after various loadings of XNBRP were added. Results clearly show that the presence of XNBRP not only leads to increased compound viscosity but also causes deterioration of the mechanical properties, e.g., tensile strength, tear strength, abrasion resistance, rebound resilience, as well as compression set at elevated temperature. This is mainly attributed to the reduced cross‐link density and the poor interfacial adhesion between NR and XNBRP. However, both oil and thermal ageing resistances are found to improve continuously with increasing XNBRP loading. Such improvement is obvious when 20 phr of XNBRP is loaded. Although the rubber becomes softer after oil immersion, it is surprisingly found that the modulus at high strain of the swollen rubber is greater than that of the unswollen one. The network tightening effect is proposed to explain the results. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 183–190, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20215
Polymeric foams from high‐performance thermoplastics
Authors: Sorrentino L. , Aurilia M. , Iannace S.
Published: August 2011

The aim of this work was to investigate the foaming process of high‐performance thermoplastic polymers such as polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI), and poly(ethylene‐2,6‐naphthalate) (PEN) expanded by using supercritical carbon dioxide as a blowing agent. All polymers were characterized by differential scanning calorimetry (DSC) and rheological analysis to roughly identify the foaming conditions. Batch and solid‐state foaming methods were employed. In the first case, cell nucleation was promoted by inducing a fast pressure drop rate in a pressurized vessel. In the solid‐state process, foaming was promoted by increasing the temperature of gas‐saturated samples in an oil bath. The effects of foaming methods and process parameters on cellular morphology were analyzed. All polymers were successfully foamed by using the solid‐state technique, showing relative densities ranging from 0.13 to 0.44 for PEN and from 0.27 to 0.57 for PES, PPSU, and PEI. The morphology was microcellular in all cases, and PES exhibited nanocellular cells after some processing conditions. The batch‐foaming process was less effective to prepare foams than the solid‐state one. In fact, higher relative densities and reduced temperature windows for foaming were evidenced for amorphous polymers, whereas PEN crystallized during the heating step and foams with poor morphology and high relative densities were obtained. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 30: 234–243, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20219
Chemical kinetic modeling of i‐butane and n‐butane catalytic cracking reactions over HZSM‐5 zeolite
Authors: Roohollahi Gholamreza , Kazemeini Mohammad , Mohammadrezaee Alireza , Golhosseini Reza
Published: August 2011

A chemical kinetic model for i‐butane and n‐butane catalytic cracking over synthesized HZSM‐5 zeolite, with SiO2/Al2O3 = 484, and in a plug flow reactor under various operating conditions, has been developed. To estimate the kinetic parameters of catalytic cracking reactions of i‐butane and n‐butane, a lump kinetic model consisting of six reaction steps and five lumped components is proposed. This kinetic model is based on mechanistic aspects of catalytic cracking of paraffins into olefins. Furthermore, our model takes into account the effects of both protolytic and bimolecular mechanisms. The Levenberg–Marquardt algorithm was used to estimate kinetic parameters. Results from statistical F‐tests indicate that the kinetic models and the proposed model predictions are in satisfactory agreement with the experimental data obtained for both paraffin reactants. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2456–2465, 2012
Impact of intrasexual selection on sexual dimorphism and testes size in the Mexican howler monkeysAlouatta palliataandA. pigra
Authors: Kelaita Mary , Dias Pedro Américo D. , Aguilar‐Cucurachi Ma. del Socorro , Canales‐Espinosa Domingo , Cortés‐Ortiz Liliana
Published: August 2011

One of the goals of physical anthropology and primatology is to understand how primate social systems influence the evolution of sexually selected traits. Howler monkeys provide a good model for studying sexual selection due to differences in social systems between related species. Here, we examine data from the sister howler monkey speciesAlouatta palliataandA. pigrainhabiting southeastern Mexico and northern Guatemala. We use a resampling approach to analyze differences in sexual dimorphism of body and canine size. In addition, we compare testes size as a way of gauging the intensity of sperm competition in both species. Morphometric data were collected from wild‐caught individuals, including body mass and length, and dental data were obtained from casts from wild individuals and from museum specimens. AlthoughA. pigraindividuals are larger than theirA. palliatacounterparts, we find that both species exhibit similar levels of sexual dimorphism for all of the variables considered. Testicular volume results indicate thatA. palliatamale testes are on average twice as large as those ofA. pigramales, suggesting more intense sperm competition in the former species. Our study shows thatA. pigrais not highly sexually dimorphic as was once thought, and testes size differences suggest the need for a clearer understanding of howler monkey social systems. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Flame‐retarded polystyrene with phosphorus‐ and nitrogen‐containing oligomer: Preparation and thermal properties
Authors: Tai Qilong , Song Lei , Lv Xiaoqi , Lu Hongdian , Hu Yuan , Yuen Richard K.K.
Published: August 2011

A phosphorus‐ and nitrogen‐containing compound (2‐dimethylamino ethyl phenyl hydroxyethyl acrylate phosphate) and its oligomer (poly(2‐dimethylamino ethyl phenyl hydroxyethyl acrylate phosphate), PDPHP) were synthesized and characterized. The polystyrene (PS) composites with various amounts of PDPHP were prepared by melt blending. The thermal stability of the PDPHP and PS composites was investigated by thermogravimetric analysis. The flame retardancy of the composites was evaluated using microscale combustion calorimeter and limiting oxygen index test. A Fourier transform infrared (FTIR) spectroscopy coupled with a thermogravimetric analyzer was also used to study the gas phase from the degradation of PS composites. The char residues of the PS composites containing 30 wt % PDPHP were analyzed by FTIR and scanning electron microscopy. The results suggest that the incorporation of PDPHP into PS can evidently enhance the char formation and improve the flame retardancy of virgin PS. The compact and coherent char formed during degradation was attributed to the enhancement of char quality and flame retardance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and properties of composites of oligoazomethine with char
Authors: Özaytekin İlkay , Kar Yakup
Published: August 2011

Conjugated aromatic oligo(azomethine) derivatives (oligo‐AMs) were prepared by the condensation of terephtaldehyde 4,4′‐diformylbiphenyl bis(4‐formylphenyl) ether and p‐phenylene diacrolein with 1,4‐diaminobenzene at room temperature. The structures of the synthesized oligomers were characterized by FTIR, 1H‐NMR, TGA–DTG, UV–vis absorption spectra, and elemental analyses. Additionally, in this study, the oligomer composites were obtained using the carbon material (char) derived from the 450°C pyrolysis of waste polyethylene terephthalates. The conductivity measurements of the produced composites were determined at 24‐h periods by doping with iodine vapor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical and drug delivery properties of a chitosan–tartaric acid hydrogel suitable for biomedical applications
Authors: Ruiz‐Caro R. , Veiga M. D. , Di Meo C. , Cencetti C. , Coviello T. , Matricardi P. , Alhaique F.
Published: August 2011

The present investigation describes the synthesis and the characterization of a novel highly stable polysaccharidic hydrogel system, designed for modified drug delivery. Gels and films based on the biodegradable and biocompatible chitosan (CS) were prepared by a crosslinking reaction between the polysaccharide amino groups with tartaric acid, using the short‐range crosslinkers 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide (EDC) and N‐hydroxysuccinimide (NHS) as coupling agents. The aim of the study is to characterize the novel CS hydrogel by means of rheological and mechanical measurements; in vitro swelling, release, and degradation studies were also carried out. Obtained results show how the structure of the obtained networks can deeply affect dynamomechanical properties of the hydrogel as well as the delivery rate of loaded model drugs. The mechanical characterization of the hydrogel, in the form of films, indicates that the film elasticity increases as the water content in the hydrogel increases. Rheological studies evidenced that the different network structures can affect the elastic modulus of the system. Release studies of two model molecules, i.e., vitamin B12 and blue dextran, of different steric hindrance were carried out using both the bulk gel and the film. In vitro release of both drugs was evaluated in water and in Hepes to assess the suitability of this novel drug delivery system for pharmaceutical applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Diazotization–azidation of amines in water by using crosslinked poly(4‐vinylpyridine)‐supported azide ion
Authors: Karimi Zarchi Mohammad Ali , Nabaei Rahman , Barani Saeed
Published: August 2011

The use of polymeric reagents simplifies routine azidation of diazonium salts, because it eliminates the traditional purification. An efficient, simple, and effective method for the preparation of aryl azides is described. The synthesis of aromatic azides from the corresponding amines is accomplished under mild conditions with sodium nitrite in the presence of p‐toluenesulfonic acid or concentrated H2SO4 at low temperature (0–5°C to room temperature). The obtained relatively stable diazonium salts, followed by treatment with a polymer‐supported azide ion in water at room temperature to produce the corresponding aryl azides. The spent polymeric reagents can be regenerated and reused for several times without losing their activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Chemical structure and catalytic activity of quaternary onium salt‐type triphase catalysts based on CPS microspheres
Authors: Gao Baojiao , Wang Zhangbin , Wang Lin
Published: August 2011

In this work, diversified quaternary onium salt‐type triphase catalysts (TPC) were prepared based on crosslinked polystyrene (CPS) microspheres, and the relationship between their chemical structures and catalytic activities in liquid‐solid‐liquid reaction system were investigated in depth by using the esterification reaction of benzyl chloride with sodium acetate as a model system. The experimental results indicate that the chemical structures of the TPC affect their catalytic activity greatly and there are four basic points: (1) the quaternary phosphonium‐type TPC have higher activity than quaternary ammonium‐type catalyst; (2) the TPC with more lipophilic substitutes at N atom have higher catalytic activity; (3) the TPC with longer spacer arm, which links quaternary onium salt group to the matrix microsphere, have higher catalytic activity; (4) the bonding density of quaternary onium salt group on the polymeric carrier affects the hydrophilic and hydrophobic property of the TPC, and consequently, influences the catalytic activity significantly. For a given triphase catalysis system, there is an optimal bonding density of quaternary onium salt group on the solid catalysts. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optical resolution of racemic amino acid derivatives with chiral polyamides bearing glutamyl residue as a diacid component
Authors: Nakagawa Maiko , Ikeuchi Yoshimi , Yoshikawa Masakazu , Yoshida Hidekazu , Sakurai Shinichi
Published: August 2011

Novel chiral polyamides with chiral environment in their main chains were obtained from aromatic diamine, 4,4′‐diaminodiphenylmethane (DADPM), and the D‐isomer or the L‐isomer of N‐α‐protected glutamic acid, such as N‐α‐benzyloxycarbonyl‐D‐glutamic acid (Z‐D‐Glu‐OH) or N‐α‐benzyloxycarbonyl‐L‐glutamic acid (Z‐L‐Glu‐OH), in the presence of triphenyl phosphite (TPP). Two types of newly prepared polyamide showed optical rotation, implying that there were asymmetric carbons in their main chains. Circular dichroism studies demonstrated that resulting chiral poly‐ amides took a helical structure. Optical resolution ability of those two types of polyamide was studied by adopting potential difference as a driving force for membrane transport. Membranes showed permselectivity toward racemic mixture of N‐α‐acetyltryptophan (Ac‐Trp). The permselectivity was dependent on the absolute configuration of diacid component. The permselectivity was expressed by diffusivity selectivity, which was determined by the presence of chiral helicity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Hydrogels composite of poly(acrylamide‐co‐acrylate) and rice husk ash. I. Synthesis and characterization
Authors: Cândido Jean de S. , Leitão Renan C. F. , Ricardo Nágila M. P. S. , Feitosa Judith P. A. , Muniz Edvani C. , Rodrigues Francisco H. A.
Published: August 2011

Composite hydrogels of poly(acrylamide‐co‐acrylate) with rice husk ash (RHA) were synthesized and studies of the swelling variables were accomplished comparatively with commercial polyacrylamide gel and PAMACRYL, a poly(acrylamide‐co‐acrylate) hydrogel without RHA. FT‐IR and WAXS were the techniques employed for characterizing a series of hydrogel obtained by varying the percentage of RHA (1, 2, 5, 10, and 20 wt %) and the amount of crosslinking agent (0.05, 0.1, and 0.2 mol %) relative to sum of AAm and AAc. Superabsorbent hydrogel with Weq > 800 g H2O/g gel was obtained with percentage of 10 wt % of RHA and 0.1 of crosslinking agent mol %. The hydrogel showed to be sensitive to the pH variation and to the presence of salts. The hydrogels, even though submitted through cycles of drying and swelling, preserved their superabsorbent characteristics and demonstrated better water absorbance properties when compared with commercial polyacrylamide gel. The composite hydrogels of poly(acrylamide‐co‐acrylate) with RHA presented good characteristics to be applied as soil conditioner for using in agriculture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Einfluss von Wärmedämmverbundsystemen auf das Sommerverhalten von Gebäuden
Authors: Handler Simon , Korjenic Azra , Bednar Thomas
Published: August 2011

Im Rahmen des hier präsentierten Forschungsprojekts wurden Wärmedämmverbundsysteme (WDVS) auf deren Potential zur Beschränkung der sommerlichen Überwärmung von Gebäuden in unterschiedlichen Klimaregionen mit experimentellen und numerischen Methoden untersucht. An einem Institutsgebäude der TU Wien wurden im Rahmen eines Experiments die Wärmetransportprozesse während des Sommers 2010 durch eine Außenwand mit WDVS und durch eine Außenwand ohne WDVS mit einer Messanlage bestehend aus Wärmestrommessfolien sowie Temperatur‐ und Strahlungssensoren erfasst. Im Anschluss wurden dynamische Gebäudesimulationen für zwei verschiedene Klimasituationen durchgeführt. Für eine festgelegte Gebäudegeometrie wurde der Einfluss von WDVS auf die sich einstellenden Innenraumtemperaturen untersucht. Es wurde speziell darauf eingegangen, ob temperatursenkende Maßnahmen (nächtliches Dauerlüften, Verschattung der Fensterflächen) an Außenwänden mit WDVS ähnlich hohe Wirkung zeigen wie an Außenwänden ohne WDVS.

The influence of external thermal insulation composite systems on the summer performance of buildings. In this research the potential of external thermal insulation composite systems (ETICS) to reduce the overheating of buildings during summertime is researched by experimental and numerical methods. An experiment is carried out to explore how the heat transport processes through an exterior wall are affected by the installation of a thermal insulation composite system. As part of the preparation for the experiment, an exterior insulation layer is installed on part of the facade of a building. The heat transport processes through the wall are then detected by a measuring system consisting of heat flow sensors, temperature sensors and radiation sensors. If the obtained knowledge is valid for various outside temperatures, is then verified by performing dynamic, thermal simulations of a defined building located in different climatic situations. The other topic that is investigated by the thermal building simulations is the effect of operations that may reduce indoor temperatures (e. g. constant airing over open windows during night, using shading systems for the windows) and the used wall constructions on the room temperatures that actually occur.
Safety assessment of ultra‐wideband antennas for microwave breast imaging
Authors: De Santis Valerio , Sill Jeff M. , Bourqui Jeremie , Fear Elise C.
Published: August 2011

This article deals with the safety assessment of several ultra‐wideband (UWB) antenna designs for use in prototype microwave breast imaging systems. First, the performances of the antennas are validated by comparison of measured and simulated data collected for a simple test case. An efficient approach to estimating the specific energy absorption (SA) is introduced and validated. Next, SA produced by the UWB antennas inside more realistic breast models is computed. In particular, the power levels and pulse repetition periods adopted for the SA evaluation follow the measurement protocol employed by a tissue sensing adaptive radar (TSAR) prototype system. Results indicate that the SA for the antennas examined is below limits prescribed in standards for exposure of the general population; however, the difficulties inherent in applying such standards to UWB exposures are discussed. The results also suggest that effective tools for the rapid evaluation of new sensors have been developed. Bioelectromagnetics 33:215–225, 2012. © 2011 Wiley Periodicals, Inc.
The Route to a Feasible Hydrogen‐Storage Material: MOFs versus Ammonia Borane
Authors: Hügle Thomas , Hartl Monika , Lentz Dieter
Published: August 2011

The replacement of fossil fuels is one of the greatest challenges that chemistry and material sciences will have to face in the near future. While hydrogen seems to be the most likely candidate for this, a material able to store the hydrogen itself is sorely needed. Intense research in the past decade has narrowed down the field of possible concepts to two materials: ammonia borane with chemically bound hydrogen atoms and metal–organic frameworks with physisorbed hydrogen molecules. Herein we want to give an overview of the strengths and weaknesses of each concept, discuss the challenges that need to be overcome, and try to compare the future capabilities of these two materials.
Bis[3,5‐bis(benzylidene)‐4‐oxo‐1‐piperidinyl]amides: A Novel Class of Potent Cytotoxins
Authors: Das Swagatika , Das Umashankar , Varela‐Ramírez Armando , Lema Carolina , Aguilera Renato J. , Balzarini Jan , De Clercq Erik , Dimmock Stephen G. , Gorecki Dennis K. J. , Dimmock Jonathan R.
Published: August 2011

The principal objective of this study was the examination of the theory of cytotoxic synergism. In this exploratory study, we tested the hypothesis that doubling the number of sites available for thiol alkylation in a series of candidate cytotoxins increases potency more than two‐fold. This concept was verified in one‐third of our comparisons using human Molt 4/C8 and CEM T‐lymphocytes and murine L1210 cells. In addition, the significant potencies of various members of our compound series justified further studies. Molecular modeling revealed that relative locations of the amidic groups correlate with cytotoxicity. A potent cytotoxic compound, 1,2‐bis(3,5‐dibenzylidene‐4‐oxo‐piperidin‐1‐yl)ethane‐1,2‐dione (1 a) inhibited the growth of a large number of human tumor cell lines and displayed greater toxicity toward certain non‐adherent cells than toward adherent neoplasms or fibroblasts. The mode of action of 1 a includes induction of apoptosis and necrosis.
Parallel feedback pathways in visual cortex of cats revealed through a modified rabies virus
Authors: Connolly Jason D. , Hashemi‐Nezhad Maziar , Lyon David C.
Published: August 2011

The visual cortex of cats is highly evolved. Analogously to the brains of primates, large numbers of visual areas are arranged hierarchically and can be parsed into separate dorsal and ventral streams for object recognition and visuospatial representation. Within early primate visual areas, V1 and V2, and to a lesser extent V3, the two streams are relatively segregated and relayed in parallel to higher order cortex, although there is some evidence suggesting an alignment of V2 and V3 to one stream over the other. For cats, there is no evidence of anatomical segregation in areas 18 and 19, the analogs to V2 and V3. However, previous work was only qualitative in nature. Here we re‐examined the feedback connectivity patterns of areas 18/19 in quantitative detail. To accomplish this, we used a genetically modified rabies virus that acts as a retrograde tracer and fills neurons with fluorescent protein. After injections into area 19, many more neurons were labeled in putative ventral stream area 21a than in putative dorsal stream region posterolateral suprasylvian complex of areas (PLS), and the dendrites of neurons in 21a were significantly more complex. Conversely, area 18 injections labeled more neurons in PLS, and these were more complex than neurons in 21a. We infer from our results that area 19 in cat is more aligned to the ventral stream and area 18 to the dorsal stream. Based on the success of our approach, we suggest that this method could be applied to resolve similar issues related to primate V3. J. Comp. Neurol. 520:988–1004, 2012. © 2011 Wiley Periodicals, Inc.
Increasing end‐to‐end fairness over IEEE 802.11e‐based wireless mesh networks
Authors: Abouaissa Abdelhafid , Brahmia Mohamed‐el‐Amine , Lorenz Pascal
Published: August 2011

In this paper, we discuss the issue of fairness in the IEEE802.11e over wireless mesh networks. Fairness is an important factor that we have to achieve before talking about QoS. Inspired by social networks approximations, and to achieve fairness and provide QoS by regulating heterogeneous traffic, we extended the original IEEE802.11e protocol by introducing a new algorithm based on the ‘token bucket’ concept. We also treat the problem of exposed/hidden nodes. Simulation results show that the proposed approach offers better performance than the IEEE802.11e one. Copyright © 2011 John Wiley & Sons, Ltd.
Verankerungen im Mauerwerk – Was ist neu in Europa?
Authors: Becker Rainer , Block Klaus
Published: August 2011

Durch die Einführung der beiden Leitlinien ETAG 020 [1] zur Beurteilung und Bemessung von Kunststoffdübeln in Beton und Mauerwerk sowie ETAG 029 [2] zur Beurteilung und Bemessung von Injektionsverankerungen in Mauerwerk ist die Basis zur Erteilung europäischer technischer Zulassungen gelegt worden. Der Artikel stellt die Unterschiede zwischen dem bisherigen Zulassungscharakter nationaler Zulassungen und den europäischen technischen Zulassungen dar. In diesem Zusammenhang werden die Grundprinzipien der verschiedenen Verankerungen sowie die resultierenden Untersuchungen erläutert. Besonderes Augenmerk wird schließlich auf die Durchführung von Baustellenversuchen gelegt. Aufgrund der bisherigen Erfahrungen und der Erfordernisse der beiden Leitlinien wird die Durchführung dieser Versuche und die Bewertung der Ergebnisse erläutert.

Fastenings in Masonry – News from Europe? Due to the publishment of the guidelines ETAG 020 [1] for evaluation and design of polymeric anchors in concrete and masonry units as well as ETAG 029 [2] for evaluation and design of bonded anchors in masonry the basis is laid for granting European technical approvals. This article describes the differences between the present national approvals and the European technical approvals. Furthermore the principles of anchorage between the different fastenings and the related determinations are shown. Special attention is paid to the job site tests finally. Conducting of these tests and the assessment of the results are explained due to the current experience and the requirements of the two guidelines.
Masonry fastenings for double‐leaf façades – the state of the art
Authors: Modersohn Wilhelm , Hübers Reinhold
Published: August 2011

Zweischalige Mauerwerksfassaden sind aufgrund ihrer hervorragenden Eigenschaften im Bereich der Wärmedämmung, Schallisolierung, Beständigkeit und der Gebäudeklimatisierung stark im Trend (s. Bild 1). Um diese Vorteile dauerhaft und wirksam nutzen zu können und um dem Bauherrn eine hohe Investitionssicherheit zu geben, kommt es besonders auf die richtige Befestigung der Vorsatzschale an. Der folgende Beitrag gibt detaillierte Hinweise und Erläuterungen zu technisch und wirtschaftlich sinnvollen Produktlösungen.
Zweischaliges Ziegelverblendmauerwerk – Stand der Technik
Authors: Altaha Nasser
Published: August 2011

Zweischaliges Ziegelverblendmauerwerk hat sich in den Gebieten mit höchster Schlagregenbeanspruchung über viele Jahrzehnte als besonders widerstandsfähig und wartungsfrei bewährt. In Norddeutschland prägen Ziegelfassaden das Bild vieler Städte und Dörfer und sind integraler Bestandteil der kulturellen Identität.

Die Entscheidung zugunsten von Ziegelfassaden ist keineswegs nur auf traditionelle Werte zurückzuführen, sondern sie unterliegt vielmehr ökologischen und ökonomischen Gesichtspunkten. Ziegelfassaden zeichnen sich insbesondere durch ihre bewährten Eigenschaften wie Dauerhaftigkeit, Wartungsfreiheit, individuelle Gestaltung und Widerstandfähigkeit gegen extreme Witterungseinflüsse aus (Bild 1).

Die zur Zeit in der Mauerwerksnorm DIN 1053‐1 [1] zusammengestellten Anforderungen an die Planung und Ausführung dieser Bauweise entsprechen nicht mehr den heute allgemein anerkannten Regeln der Bautechnik. Der vollständig überarbeitete Abschnitt für die zweischalige Wand wird künftig im nationalen Anhang der Europäischen Mauerwerksnorm DIN EN 1996‐1‐1/NA (EC 6) [2] zu finden sein. Die Europäische Mauerwerksnorm EC 6 soll im Jahre 2012 bauaufsichtlich eingeführt werden.

Die vorliegende Abhandlung zeigt den aktuellen Stand der Ausführungstechnik für zweischaliges Ziegelverblendmauerwerk und geht auf die wichtigsten Fragen zur fachgerechten Umsetzung dieser Bauweise ein.

Double faced brickwork (cavity brick construction) – State of the art. Double faced brickwork has proven itself as particularly resistant and maintenance‐free over many decades in areas with the highest rain strain. In North Germany brick facades dominate the image of many towns and villages and are an integral part of cultural identity.

The decision to go with brick facades is not just due to traditional values, but rather it is subject to environmental and economic perspectives. Brick facades are particularly distinguished by its unique properties, such as durability, maintenance, individual design and resistance to extreme weather conditions (Fig. 1).

The currently in Masonry Standard DIN 1053‐1 [1] compiled requirements for the planning and execution of this construction are no longer comply with today’s generally recognized rules of building constructions. In the future the completely revised section of the cavity wall can be found in the national annex to the European Masonry Standard DIN EN 1996‐1‐1/ NA (EC 6) [2]. The European Masonry Standard EC 6 is supposed to be introduced in 2012.

This paper shows the current state of the design technique for bivalve faced brickwork and focuses the key issues for proper implementation of this design.
Die Fehlermöglichkeits‐ und Einflussanalyse (FMEA) als Werkzeug zur Qualitätssicherung im Mauerwerksbau
Authors: Seim Werner , Vogt Tobias
Published: August 2011

Die Fehlermöglichkeits‐ und Einflussanalyse (FMEA) wurde entwickelt, um die Qualität von Produkten sicherzustellen. Es sollen mögliche Fehler in einem frühen Stadium erkannt werden, um diese bereits im Vorfeld zu vermeiden bzw. deren Folgen durch geeignete Maßnahmen zu minimieren. Sie findet im Bereich des Maschinenbaus, insbesondere in der Luft‐ und Raumfahrt sowie in der Automobilindustrie, bereits seit einigen Jahrzehnten Anwendung.

Im Rahmen eines vom Bundesinstitut für Bau‐, Stadt‐ und Raumforschung (BBSR) geförderten Forschungsprojektes wurde ein Leitfaden “Tragwerk‐FMEA“ mit Regeln zur Durchführung einer FMEA im Bauwesen formuliert. Dabei werden der Schwierigkeitsgrad und die Robustheit eines Tragwerks als diejenigen Parameter definiert, aus denen sich der nötige Umfang ableiten lässt.

Anhand eines Beispiels aus dem Mauerwerksbau wird die “Tragwerk‐FMEA“ vorgestellt.
Diagnostic concordance of the interview and questionnaire versions of the eating disorder examination
Authors: Berg Kelly C. , Stiles‐Shields E. Colleen , Swanson Sonja A. , Peterson Carol B. , Lebow Jocelyn , Le Grange Daniel
Published: August 2011

Objective:

The diagnostic concordance of the interview (EDE) and questionnaire (EDE‐Q) versions of the Eating Disorder Examination was examined.

Method:

Two‐hundred seventeen patients seeking eating disorder treatment completed the EDE and EDE‐Q before beginning treatment. Diagnostic algorithms were generated for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (DSM‐IV‐TR) and proposed Diagnostic and Statistical Manual of Mental Disorders (DSM‐5) criteria using data first from the EDE and then from the EDE‐Q; thus, each participant received four diagnoses.

Results:

The sensitivity of the EDE‐Q for individual diagnoses ranged from 27.8% to 84.3% (DSM‐IV‐TR) and from 36.8% to 80.8% (DSM‐5). The specificity of the EDE‐Q for individual diagnoses ranged from 71.1% to 98.5% (DSM‐IV‐TR) and from 77.3% to 98.0% (DSM‐5). The overall diagnostic concordance was moderate (κ = .57–.60).

Discussion:

The proposed DSM‐5 criteria improved the diagnostic concordance of the two instruments and reduced the prevalence of Eating Disorder Not Otherwise Specified (EDNOS). However, concordance improvement was modest and both instruments still diagnosed most respondents with EDNOS. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2011;45:850–855)
Ecohydrological consequences of drought‐ and infestation‐ triggered tree die‐off: insights and hypotheses
Authors: Adams Henry D. , Luce Charles H. , Breshears David D. , Allen Craig D. , Weiler Markus , Hale V. Cody , Smith Alistair M. S. , Huxman Travis E.
Published: August 2011

Widespread, rapid, drought‐, and infestation‐triggered tree mortality is emerging as a phenomenon affecting forests globally and may be linked to increasing temperatures and drought frequency and severity. The ecohydrological consequences of forest die‐off have been little studied and remain highly uncertain. To explore this knowledge gap, we apply the extensive literature on the ecohydrological effects of tree harvest in combination with the limited existing die‐off ecohydrology research to develop new, relevant hypotheses. Tree mortality results in loss of canopy cover, which directly alters evaporation, transpiration, and canopy interception and indirectly alters other watershed hydrologic processes, including infiltration, runoff, groundwater recharge, and streamflow. Both die‐off and harvest research suggest that for most forests, water yield can be expected to increase following substantial loss of tree cover by die‐off. We hypothesize that where annual precipitation exceeds ∼500 mm or water yield is dominated by snowmelt, watersheds will experience significantly decreased evapotranspiration and increased flows if absolute canopy cover loss from die‐off exceeds 20%. However, recent observations suggest that water yield following die‐off can potentially decrease rather than increase in drier forests. To reliably predict die‐off responses, more research is needed to test these hypotheses, including observations of multiple water budget components and the persistence of ecohydrological effects with the post‐die‐off successional dynamics of tree recruitment, understorey growth, and interactions with additional disturbances. With die‐off, mitigation and restoration options are limited and costly, necessitating societal adaptation; therefore, die‐off ecohydrology should be a high priority for future research. Published in 2011. This article is a US Government work and is in the public domain in the USA.
Chiral 1,1′‐Bi(tetrahydroisoquinoline)‐Type Diamines as Efficient Ligands for Nickel‐Catalysed Enantioselective Michael Addition to Nitroalkenes
Authors: Wilckens Kristina , Duhs Marcel‐Antoine , Lentz Dieter , Czekelius Constantin
Published: August 2011

A chiral C2‐symmetric 1,2‐diamine based on a 1,1′‐bi(tetrahydroisoquinoline) scaffold was found to be an efficient ligand for the enantioselective NiII‐catalysed Michael addition of malonic esters to conjugated nitroalkenes. The reactions proceed with 92–99 % yield and 91–99 % enantioselectivity even at elevated temperatures. The solid‐state structure of the catalyst precursor revealed intramolecular π–π stacking as well as supramolecular halogen···halogen bonding interactions.
Dielectrophoretic capture of E. coli cells at micropatterned nanoelectrode arrays
Authors: Syed Lateef U. , Liu Jianwei , Price Alex K. , Li Yi‐fen , Culbertson Christopher T. , Li Jun
Published: August 2011

This paper reports capture and detection of pathogenic bacteria based on AC dielectrophoresis (DEP) and electrochemical impedance spectroscopy (EIS) employing an embedded vertically aligned carbon nanofiber (VACNF) nanoelectrode array (NEA) versus a macroscopic indium‐tin‐oxide (ITO) transparent electrode in “points‐and‐lid” configuration. The nano‐DEP device was fabricated using photolithography processes to define an exposed active region on a randomly distributed NEA and a microfluidic channel on ITO to guide the flow of labeled Escherichia coli cells, respectively, and then bond them into a fluidic chip. A high‐frequency (100 kHz) AC field was applied to generate positive DEP at the tips of exposed CNFs. Enhanced electric field gradient was achieved due to reduction in electrode size down to nanometer scale which helped to overcome the large hydrodynamic drag force experienced by E. coli cells at high flow velocities (up to 1.6 mm/s). This DEP device was able to effectively capture a significant number of E. coli cells. Significant decrease in the absolute impedance at the NEA was observed in EIS experiments. The results obtained in this study suggest the possibility of integration of a fully functional electronic device for rapid, reversible and label‐free capture and detection of pathogenic bacteria.
Dielectrophoretic mobility determination in DC insulator‐based dielectrophoresis
Authors: Weiss Noah G. , Jones Paul V. , Mahanti Prasun , Chen Kang P. , Taylor Thomas J. , Hayes Mark A.
Published: August 2011

Insulator‐based dielectrophoresis (iDEP) is a powerful tool for separating and characterizing particles, yet it is limited by a lack of quantitative characterizations. Here, this limitation is addressed by employing a method capable of quantifying the DEP mobility of particles. Using streak‐based velocimetry the particle properties are deduced from their motion in a microfluidic channel with a constant electric field gradient. From this approach, the DEP mobility of 1 μm polystyrene particles was found to be −2±0.4 10−8 cm4/(V2 s). In the future, such quantitative treatment will allow for the elucidation of unique insights and rational design of devices.
Dielectrophoretic monitoring of microorganisms in environmental applications
Authors: Jesús‐Pérez Nadia M. , Lapizco‐Encinas Blanca H.
Published: August 2011

Dielectrophoresis (DEP) is the motion of polarizable particles in the presence of nonuniform electric fields. This novel electrokinetic technique has successfully been employed in many miniaturized systems for the manipulation and detection of microbes. This review article depicts the application of dielectrophoresis for the monitoring of microorganisms in microfluidic devices for environmental applications. The research studies described here are mainly conceived for water‐ and air‐monitoring assessments, and are classified considering the target aimed to detect, concentrate, and/or separate, including chemical and toxicant agents, and microorganisms ranging from virus to protozoa. Dielectrophoresis has also played an important role in biofilm formation studies. This review article comprises mainly studies published from 2000 to present. Even in this relatively short time frame, there have been many significant contributions of this powerful and nascent technique related to environmental monitoring; thus, unveiling its great potential for future research directions.
Internalizing and Externalizing Behaviour Problems in Childhood Contribute to the Development of Anorexia and Bulimia Nervosa—A Study Comparing Sister Pairs
Authors: Adambegan Mandana , Wagner Gudrun , Nader Ingo W. , Fernandez‐Aranda Fernando , Treasure Janet , Karwautz Andreas
Published: August 2011

Objective

We wanted to clarify whether there is any clinically relevant behavioural psychopathology in patients before onset of an eating disorder (ED) compared with their healthy sisters and if there are differences in behavioural problems between the ED subtypes anorexia nervosa—restricting type (AN‐R) and EDs with bulimic behaviour.

Method

Behavioural psychopathology was examined by parental report using the Child Behaviour Checklist retrospectively in 83 sister pairs discordant for an ED (37 with AN‐R and 46 with bulimic EDs) by means of conditional logistic regression.

Results

Participants who later developed an ED had significantly higher internalizing and externalizing behavioural abnormality scores before onset of the ED than their unaffected sisters. Conditional logistic regression revealed significantly higher internalizing behaviour scores in AN‐R and significantly higher internalizing and externalizing scores in the bulimic disorders.

Discussion

Internalizing problems (anxiety, depression and somatization) preceded the development of AN, whereas both internalizing and externalizing behaviour problems (aggressive and delinquent behaviour) preceded bulimic disorders. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.
The Accuracy of Non‐traditional versus Traditional Methods of Forecasting Lumpy Demand
Authors: Mukhopadhyay Somnath , Solis Adriano O. , Gutierrez Rafael S.
Published: August 2011

Forecasting for inventory items with lumpy demand is difficult because of infrequent nonzero demands with high variability. This article developed two methods to forecast lumpy demand: an optimally weighted moving average method and an intelligent pattern‐seeking method. We compare them with a number of well‐referenced methods typically applied over the last 30 years in forecasting intermittent or lumpy demand. The comparison is conducted over about 200,000 forecasts (using 1‐day‐ahead and 5‐day‐ahead review periods) for 24 series of actual product demands across four different error measures. One of the most important findings of our study is that the two non‐traditional methods perform better overall than the traditional methods. We summarize results and discuss managerial implications. Copyright © 2011 John Wiley & Sons, Ltd.
Novel GLP‐1 mimetics in diabetes: lixisenatide and albiglutide
Authors: Seewoodhary Jason , Davies John
Published: August 2011

Lixisenatide and albiglutide are glucagon‐like peptide‐1 (GLP‐1) agonists in clinical development that are similar to exenatide and liraglutide. This review critically considers the emerging evidence on the pharmacology, efficacy, safety and potential roles these two agents may have in clinical practice.
Multiple cellular and molecular mechanisms Are involved in human Aβ clearance by transplanted adult astrocytes
Authors: Pihlaja Rea , Koistinaho Jari , Kauppinen Riitta , Sandholm Jouko , Tanila Heikki , Koistinaho Milla
Published: August 2011

Astrocytes and microglia are able to degrade potentially neurotoxic β‐amyloid (Aβ) deposits typical for Alzheimer's disease (AD) pathology. Contrary to microglia, astrocytes degrade human Aβ from tissue sections in vitro without any additional stimulation, but it has remained unclear whether transplanted astrocytes are able to clear deposited human Aβ in vivo. We transplanted adult mouse astrocytes into the hippocampi of transgenic mice mimicking AD and observed their fate, effects on microglial responses, and Aβ clearance. After 2‐months follow‐up time, we discovered a significant reduction in Aβ burden compared with AD mice infused with PBS only. The remaining Aβ deposits were fragmented and most of the Aβ immunoreactivity was seen within the transplanted astrocytes. Concomitant to Aβ reduction, both CD68 and CD45 immunoreactivities were significantly upregulated but phagocytic microglia were often surrounding and engulfing Aβ burdened, TUNEL‐positive astrocytes rather than co‐localizing with Aβ alone. Astrocytes are known to degrade Aβ also by secreting proteases involved in Aβ catabolism. To study the contribution of neprilysin (NEP), angiotensin‐converting enzyme‐1 (ACE‐1), and endothelin‐converting enzyme‐2 (ECE‐2) in human Aβ clearance, we utilized an ex vivo assay to demonstrate that adult astrocytes respond to human Aβ by upregulating NEP expression. Further, incubation of adult astrocytes with known inhibitors of NEP, ACE‐1, or ECE‐2 significantly inhibited the removal of human Aβ from the tissue suggesting an important role for these proteases in Aβ clearance by adult astrocytes ex vivo. © 2011 Wiley‐Liss, Inc.
Decreased frontostriatal microstructural organization in attention deficit/hyperactivity disorder
Authors: de Zeeuw Patrick , Mandl René C.W. , Hulshoff Pol Hilleke E. , van Engeland Herman , Durston Sarah
Published: August 2011

Frontostriatal brain areas have been implicated in the neurobiology of attention deficit/hyperactivity disorder (ADHD), but little work has directly addressed the white matter connections between these regions. The present study investigates the microstructural organization and myelination of frontostriatal white matter in children with ADHD and controls. Diffusion tensor imaging and magnetization transfer imaging scans were acquired in 30 children with ADHD and 34 controls. A study specific volume of interest (VOI) of frontostriatal white matter was created using a tractography based statistical group map. Fractional anisotropy (FA, indexing microstructural organization) and magnetization transfer ratio (MTR, indexing macromolecular content, myelin in particular) were computed for the frontostriatal VOI and for total cerebral white matter. Exploratory analyses were conducted investigating the effect of stimulant use on these measures. Frontostriatal FA but not MTR was decreased in ADHD compared with controls. There were no differences in FA or MTR for total cerebral white matter. Frontostriatal FA correlated negatively with teacher‐rated attention problems in controls but not children with ADHD. The duration of stimulant use did not affect the main results. Changes in frontostriatal connectivity in ADHD appear to be related to changes in microstructural organization rather than myelination per se. A correlation with attention problems for controls suggests that frontostriatal organization is relevant to ADHD‐related behaviors. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc
Event‐related potential activity in the basal ganglia differentiates rewards from nonrewards: Temporospatial principal components analysis and source localization of the feedback negativity: Commentary
Authors: Cohen Michael X , Cavanagh James F. , Slagter Heleen A.
Published: August 2011

Foti et al. propose that a reward‐related brain potential component recorded from scalp EEG is generated by deep brain basal ganglia structures. Previous work, cited in their original article, provides only speculative and theoretical support for this interpretation. Based on empirical and anatomical evidence, we argue that this scalp‐recorded ERP component is highly unlikely to be generated by the basal ganglia. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc.