bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly water‐selective mixed matrix membranes from natural rubber‐blend‐poly(acrylic acid) (NR‐blend‐PAA) incorporated with zeolite 4A for the dehydration of water–ethanol mixtures through pervaporation
Authors: Amnuaypanich S. , Naowanon T. , Wongthep W. , Phinyocheep P.
Published: February 2012

The mixed matrix membranes (MMMs) were developed from a composite of hydrophobic‐hydrophilic NR‐blend‐PAA with zeolite 4A. A separation performance of the MMMs was investigated by performing the pervaporation dehydration of water–ethanol mixtures. The results showed a dramatically greater flux of water than the ethanol flux indicating that the developed membranes were highly water‐selective. Upon incorporating of zeolite 4A, the flux and separation factor were significantly improved. Increasing the water content in the water–ethanol feed mixtures resulted in an increase in both water and ethanol fluxes leading to a decrease in water separation factor. Similarly a flux‐separation factor trade‐off was observed as raising feed temperature. The water permeance, however, declined when either the feed water concentration or the feed temperature increased. This suggests that the driving force, i.e. the partial pressure difference, has a pronounced effect on the water flux enhancement. Conversely, the driving force was less influential on the ethanol permeance. The activation energies of the permeations obtained from the Arrhenius plots, showed the lower activation energies of water permeation than those of ethanol permeation; this is because water molecules experiences less restrictive passage through the membranes compared with ethanol molecules. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of pluronic F127 on the polymorphism and thermoresponsive properties of PVDF blend membranes via immersion precipitation process
Authors: Du Chun‐Hui , Wu Chun‐Jin , Wu Li‐Guang
Published: February 2012

Amphiphilic copolymer Pluronic F127 was used as macromolecular additive to investigate the polymorphism and thermoresponsive properties of poly(vinylidene fluoride) (PVDF) membranes. Fourier transform infrared spectrometer (FTIR), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) were conducted to characterize the polymorphism and morphology of PVDF/F127 blend membranes. FTIR results indicated that F127 existed stably in the blend membranes, and lower F127 concentration in the cast solution was in favor of the formation of α‐crystal phase, but higher F127 concentration could promote the formation of β‐ and γ‐crystal phase in PVDF membranes. The results of XRD also confirmed these phenomena. With the increase of F127 in the cast solutions, a more sponge‐like structure appeared at the bottom surface of the membranes as investigated by SEM. PVDF/F127 blend membranes also exhibited good thermoresponsive properties. The water flux of the membranes increased distinctly with the increase of the experimental temperature, decreased with the decrease of the temperature, and the increasing and decreasing curves were almost overlapped. Contact angle measurement and permeation experiment indicated that the blend membranes had good hydrophilicity and fouling resistance. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterizations of transparent polyimide nanocomposite films with various equibiaxial stretching ratios: Optical transparency, morphology, and oxygen permeability
Authors: Min Ungki , Yoon Choon Sup , Chang Jin‐Hae
Published: February 2012

A series of transparent polyimide (PI) nanocomposite films was synthesized from bicyclo(2,2,2)oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride and 1,3‐bis(3‐aminophenoxy) benzene with various organoclay contents via solution intercalation polymerization to poly(amic acid)s, followed by thermal imidization. Varying the organoclay loading in the range 0–1.5 wt % produced variations in the optical transparency, morphology, and oxygen barrier properties of the hybrids. The optimum oxygen barrier properties were observed for the hybrids containing 1.0 wt % Cloisite 30B; these properties were degraded gradually by further increases in the clay content. The PI hybrid films were found to exhibit excellent optical transparency and to be almost colorless. However, the transparency of the hybrid films decreased slightly with increasing organoclay content. Transparent PI hybrid films containing 1.0 wt % Cloisite 30B were stretched equibiaxially with various stretching ratios in the range 100–140% to investigate their optical transparency and oxygen permeability in detail; the variations with equibiaxial stretching ratio of the clay dispersion and morphology were also determined. PI hybrid films with stretching of 120% or greater were found to contain homogeneously dispersed clay in the polymer matrix and exfoliated nanocomposites. The highest barrier to oxygen permeation was found to arise at an equibiaxial stretching ratio of 130%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rheological study on tetrafluoroethylene/hexafluoropropylene copolymer and its implication for processability
Authors: Chen Xiao‐Yong , Yuan Wang Zhang , Li Hong , Zhang Yongming
Published: February 2012

Tetrafluoroethylene/hexafluoropropylene copolymers (FEPs) are widely used in diverse fields due to their outstanding performances in chemical resistance, thermal stability, and insulation. However, their processsability is poor, exhibiting narrow stable flow region and remarkably early melt fracture. Herein, we tried to explore the origin of such poor processability in a rheological way, because melt rheology behaviors are highly related to their processing processes. The shear rheology results indicate that FEPs exhibit multiple flow regions. The flow curve of FEP608 was obtained, and its η0 value was calculated to be 1.70 kPa s−1 at 360°C. Extensional rheological data suggest that FEPs have much lower e and B values when compared with those of common polymers, suggesting their weaker elasticity during extrusion. Based on such rheological results, the poor processability of FEPs is ascribed to their high viscosity induced by special interchain interaction associating with F atom, which can easily cause accumulated elastic energy. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polycaprolactone/modified bagasse whisker nanocomposites with improved moisture‐barrier and biodegradability properties
Authors: Hassan Mohammad L. , Bras Julien , Hassan Enas A. , Fadel Shaimaa M. , Dufresne Alain
Published: February 2012

Bagasse whiskers isolated from bleached bagasse pulp were chemically modified with n‐octadecyl isocyanate in the presence of dibutyltin dilaurate as a catalyst. The modified cellulose whiskers were used in ratios from 2.5 to 15% with polycaprolactone (PCL) polymer to prepare nanocomposite films by a solution/casting technique. The prepared nanocomposites were characterized with regard to their biodegradability in soil and moisture‐barrier, moisture sorption, mechanical, thermal, and thermomechanical properties. The use of the modified cellulose whiskers resulted in improvements in the moisture‐barrier, biodisintegration, and tensile properties of PCL. The nanocomposites containing different modified whisker loadings had very low moisture absorption (1.88–2.49%) after 4 weeks of exposure to 75% relative humidity, but these values were slightly higher than that of neat PCL (1.79%). Modified whiskers in the PCL matrix did not noticeably affect the glass‐transition and melting temperatures of PCL. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Oxygen‐barrier properties of poly(lactic acid)/poly(vinyl acetate‐co‐vinyl alcohol) blends as biodegradable films
Authors: Razavi S. M. , Dadbin Susan , Frounchi Masoud
Published: February 2012

The oxygen‐barrier properties of poly(lactic acid) (PLA)/poly(vinyl acetate‐co‐vinyl alcohol) [P(VAc‐co‐VA)] were investigated. P(VAc‐co‐VA)s with vinyl alcohol (VA) contents of 5, 10, and 15 mol % were prepared with the acid‐catalyzed hydrolysis of poly(vinyl acetate). The obtained copolymers with various contents of VA were blended with PLA at 5/95, 10/90, and 15/85 compositions. Films of the blends were prepared by a solution‐casting method with chloroform as the cosolvent. Although the blend with 5% VA in the copolymer appeared to be miscible, the blends with 10 and 15% VA content in the copolymer were immiscible, as verified by dynamic mechanical analysis. The oxygen‐barrier properties of the PLA films were enhanced when they were blended with P(VAc‐co‐VA). There was a reduction of about 40% in permeability with the addition of only 5% P(VAc‐co‐VA). The reduction in the permeability was more noticeable at higher VA contents. Also, the incorporation of P(VAc‐co‐VA) into PLA improved the elongation at break of the films significantly. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Ordered mesoporous carbons with various pore sizes: Preparation and naphthalene adsorption performance
Authors: Wang Keliang , Huang Bichun , Liu Dongmei , Ye Daiqi
Published: February 2012

Ordered mesoporous carbons (OMCs) with tunable pores were synthesized by a soft‐template method with F127 as a template and boric acid as a pore regulator agent. The prepared samples were characterized by small‐angle X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and N2 adsorption–desorption. The results show that the OMCs had well ordered, two‐dimensional (2D) hexagonal structures and the pore sizes were finely tunable in the range 3.4–4.7 nm when boric acid was used as the pore regulator agent. The adsorption experiments showed that the OMCs had a strong adsorption affinity to naphthalene and the maximum adsorption amount was shown to reach up to 303.2 mg/g. Furthermore, the mesopore volume between 2 and 3.5 nm of OMCs was crucial to the adsorption capacity, and OMCs with pore sizes of 2–3.5 nm were much more favorable for the naphthalene adsorption process. The adsorption isotherms of naphthalene on OMCs matched well with the Langmuir adsorption isotherm. Theoretical studies showed that the adsorption kinetics of naphthalene on OMCs accounted well for the use of the Langmuir adsorption kinetics equation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study of the dimensional instabilities of laminated polypropylene films during heating treatments
Authors: Ponçot M. , Martin J. , Hiver J. M. , Verchère D. , Dahoun A.
Published: February 2012

Ensuring the geometrical stability of organic coatings is a key challenge for steel/polymer composites produced by the automotive industry to reduce the cars' weight. During the thermal treatment of painting, which exceeds the melting temperature of the organic part of the laminated film, polymer shrinkage may occur. It induces uncovered parts of the steel sheet which would present negative corrosion behavior in use. Two original and innovative experiments were presented. They enable to measure the deformation induced by the shrinkage and then to identify the microstructural mechanisms responsible for its appearance. Main results show strong influences of the macromolecular chains orientation induced by the film extrusion process and of the postheating parameters used to perform the painting curing. Raman spectroscopy and differential scanning calorimetry are used both to perform analysis of the microstructure evolution during heating treatments in terms of crystals melting, crystalline macromolecular chains disorientation, and volume damage healing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
High‐velocity impact behavior of glass fiber‐reinforced polyester filled with nanoclay
Authors: Esfahani Javad Moftakharian , Esfandeh Masoud , Sabet Ali Reza
Published: February 2012

This study investigates the effects of nanoclay particles on impact and flexural properties of glass fiber‐reinforced unsaturated polyester (UP) composites. UP‐reinforced nanocomposite containing 1.5 and 3 wt % nanoclay was used to manufacture laminated composite panels using glass fiber woven roving by hand lay‐up method. X‐ray diffraction and transmission electron microscopy analysis confirmed intercalation and exfoliation of the nanoclay in the UP resin. Flexural test results indicated better performance for the specimens containing 1.5 wt % nanoclay reinforcements. However, Izod impact test results showed a decrease with increase in nanoclay content. High‐velocity impact tests were carried out on a gas gun in velocity range of 90–220 m/s using harden steel hemispherical tip projectile. Highest performance in ballistic limit and energy absorption were obtained for specimens containing 1.5 wt % nanoclay. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of PBAS core‐shell structured polymer by seeded emulsion polymerization and investigation in AS resin toughness
Authors: Zhao Haiyan , Liu Xinran , Fu Nian , Zhang Qingxin , Wang Nongyue , He Lianqi , Qu Xiongwei
Published: February 2012

The preparation of poly(n‐butyl acrylate)/poly(acrylonitrile‐co‐styrene), i.e., poly(BA)/poly(AN‐co‐St) (PBAS) core‐shell structured modifier with controlled particle size was reported, and the mechanical properties of AS/PBAS blends were investigated. The modifier was prepared at a solid content of 50 wt % by a two‐stage sequential emulsion polymerization. Dynamic light scattering (DLS) was used to monitor the particle diameters and showed that the particles grew without significant secondary nucleation occurring. The morphology was confirmed by means of transmission electron microscopy (TEM). According to the research on mechanical properties of the AS/PBAS blends, a remarkable toughening effect of PBAS on AS resin was found. By means of scanning electron microscopy (SEM) observation, the toughening mechanism was proposed to be crazing caused by rubber particles and shear yielding of AS matrix. Uniform dispersion of rubber particles in AS matrix was attributed to the good compatibility between AS and PBAS modifier. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Design, Synthesis, and Biological Evaluation of Bromophenol Derivatives as Protein Tyrosine Phosphatase 1B Inhibitors
Authors: Jiang Bo , Shi Dayong , Cui Yongchao , Guo Shuju
Published: February 2012

3‐Bromo‐4,5‐bis(2,3‐dibromo‐4,5‐dihydroxybenzyl)‐1,2‐benzenediol (BDB) is a bromophenol purified from the marine red alga Rhodomela confervoides and exhibits potent protein tyrosine phosphatase 1B (PTP1B) inhibition (IC50 = 1.7 µmol/L). In an effort to improve the PTP1B inhibitory activity, a series of derivatives were designed, synthesized, and evaluated in vitro. The preliminary structure–activity relationship indicated that the tricyclic scaffold and multi‐bromine atoms (four to five) attached to the aryl rings are important for PTP1B inhibition. Among these, compound 26 exhibited remarkable inhibitory activity against PTP1B with an IC50 of 0.89 µmol/L, which was approximately two‐fold more potent than the initial lead compound BDB.
Pregnancy outcome in women exposed to leflunomide before or during pregnancy
Authors: Cassina M. , Johnson D. L. , Robinson L. K. , Braddock S. R. , Xu R. , Jimenez J. L. , Mirrasoul N. , Salas E. , Luo Y. J. , Jones K. L. , Chambers C. D. ,   for the Organization of Teratology Information Specialists Collaborative Research Group
Published: February 2012

Objective

Findings from animal studies have suggested that leflunomide may be a human teratogen. In the only human cohort study published to date, an increase in adverse outcomes in pregnancies after exposure to leflunomide was not detected. The aim of the present analysis was to expand on the previously published data with a description of birth outcomes among women who did not meet the previous cohort study criteria but who were exposed to leflunomide either during pregnancy or prior to conception.

Methods

Data on pregnancy exposures and outcomes were collected from 45 pregnant women who had contacted counseling services of the Organization of Teratology Information Specialists in the US or Canada between 1999 and 2009. Sixteen women were exposed to leflunomide during the first trimester of pregnancy and 29 women were exposed preconception.

Results

All 16 of the pregnancies with leflunomide exposure during pregnancy and 27 (93%) of the pregnancies with exposure prior to conception resulted in liveborn infants. There were 2 infants with major malformations from mothers who were exposed during pregnancy, and no malformations reported in the preconception group. There was a potential known alternative etiology for at least some of the defects observed.

Conclusion

These data provide additional reassurance to women who inadvertently become pregnant while taking leflunomide and who undergo the washout procedure, as well as women who discontinue the medication prior to conception but have no prepregnancy documentation of drug clearance. However, until more conclusive data become available, women receiving leflunomide should be advised to use contraceptive methods and avoid pregnancy.
Preparation of Organometallic Ruthenium–Arene–Diaminotriazine Complexes as Binding Agents to DNA
Authors: Busto Natalia , Valladolid Jesús , Aliende Cristina , Jalón Félix A. , Manzano Blanca R. , Rodríguez Ana M. , Gaspar Jorge F. , Martins Celia , Biver Tarita , Espino Gustavo , Leal José María , García Begoña
Published: February 2012

The reactions of two diaminotriazine ligands 2,4‐diamino‐6‐(2‐pyridyl)‐1,3,5‐triazine (2‐pydaT) and 6‐phenyl‐2,4‐diamino‐1,3,5‐triazine (PhdaT) with ruthenium–arene precursors led to a new family of ruthenium(II) compounds that were spectroscopically characterized. Four of the complexes were cationic, with the general formula [(η6‐arene)Ru(κ2‐N,N‐2‐pydaT)Cl]X (X=BF4, TsO; arene=p‐cymene: 1.BF4, 1.TsO arene=benzene: 2.BF4, 2.TsO). The neutral cyclometalated complex [(η6‐p‐cymene)Ru(κ2‐C,N‐PhdaT*)Cl] (3) was also isolated. The structures of complexes 2.BF4 and 3.H2O were determined by X‐ray diffraction. Complex 1.BF4 underwent a partial reversible‐aquation process in water. UV/Vis and NMR spectroscopic measurements showed that the reaction was hindered by the addition of NaCl and was pH‐controlled in acidic solution. At pH 7.0 (sodium cacodylate) Ru–Cl complex 1.BF4 was the only species present in solution, even at low ionic strength. However, in alkaline medium (KOH), complex 1.BF4 underwent basic hydrolysis to afford a Ru–OH complex (5). Fluorimetric studies revealed that the interaction of complex 1.BF4 with DNA was not straightforward; instead, its main features were closely linked to ionic strength and to the [DNA]/complex ratio. The bifunctional complex 1.BF4 was capable of interacting concurrently through both its p‐cymene and 2‐pydaT groups. Cytotoxicity and genotoxicity studies showed that, contrary to the expected behavior, the complex species was biologically inactive; the formation of a Ru–OH complex could be responsible for such behavior.
Stability of Impulsive Stochastic Neutral Partial Differential Equations With Infinite Delays
Authors: Jiang Feng , Shen Yi
Published: February 2012

In this paper, we study the existence and asymptotic stability in the pth moment of the mild solutions to impulsive stochastic neutral partial differential equations with infinite delays. Sufficient conditions ensuring the stability of the impulsive stochastic system are established. The results are obtained via the Banach fixed point theorem.
Mechanische und physikalische Eigenschaften von mit dem Vakuumpress‐Trocknungsverfahren thermisch behandeltem Holz
Authors: Wetzig Melanie , Niemz Peter , Sieverts Tom , Bergemann Holger
Published: February 2012

Ziel der Arbeit war es, ausgewählte Eigenschaften von modifiziertem und nativem Holz zu bestimmen. Es wurden mechanische und physikalische Kenngrößen thermisch modifizierter Buchen‐, Eschen‐ und Pappelproben zweier unterschiedlicher Behandlungsintensitäten ermittelt. Zur Referenz wurden unmodifizierte Proben jeder Holzart getestet. Gegenüber anderen thermischen Vergütungsprozessen beeinflusst das Vakuumpress‐Trocknungsverfahren die Eigenschaften des Holzes weniger stark. Es entstehen auch weniger Emissionen wie Essig‐ oder Ameisensäuren. Die thermische Behandlung von Buche erzielt eine Reduzierung der Dichte und Biegefestigkeit, während die thermisch vergütete Pappel einen leichten Anstieg beider Kenngrößen aufweist. Die Eigenschaften der Esche unterscheiden sich in Abhängigkeit der Behandlungsintensität. Die mit geringer Temperatur vergüteten Proben weisen dem Referenzholz gegenüber zum Teil gestiegene Festigkeiten auf, die höher temperierten Proben stets geringere. Die Dimensionsstabilität steigt infolge der verringerten Gleichgewichtsfeuchte. Anhand der Ergebnisse ist zu erkennen, dass die Änderung der physikalischen wie auch mechanischen Eigenschaften sowohl von der Behandlungsintensität und dem angewandten Verfahren selbst als auch von der behandelten Holzart abhängt.

Mechanical and physical properties of wood, heat‐treated with the vacuum press dewatering method. The aim of this work was to analyse selected mechanical and physical behaviours of wood thermally treated with the vacuum press dewatering method, Vacu3. The density, bending and impact bending strength, modulus of elasticity, Brinell hardness and the withdrawal capacity of screws as well as the sorption capacity, change in colour and the thermal conductivity were measured. The investigated beech, ash and poplar samples were thermally treated with the patented vacuum press dewatering method, Vacu3. To test the influence of processing conditions, one type of sample was treated with medium temperatures and the other with high process temperatures. As a reference, the properties of unmodified specimen were determined. Thermal modification of beech affects a decrease in density and bending strength. The opposite is the case for heat‐treated poplar. The properties of heat‐treated ash differ depending on the degree of thermal treatment. The application of medium process temperatures on ash causes an increment in density and bending strength. In contrast, high process temperatures lead to a reduction in density and mechanical properties. As a consequence of the progressive reduction of equilibrium moisture content, the dimensional stability of heat‐treated wood is improved. The test results show that changes in properties are influenced by the treatment intensity as well as by treatment technology.
Wirkstoffauswaschung aus hydrophoben Fassadenbeschichtungen: verkapselte versus unverkapselte Biozidsysteme
Authors: Breuer Klaus , Mayer Florian , Scherer Christian , Schwerd Regina , Sedlbauer Klaus
Published: February 2012

Durch Schlagregen können biozide Wirkstoffe, die zur Verhinderung bzw. Verzögerung des Bewuchses von Fassaden mit Algen und Pilzen eingesetzt werden, aus Fassadenbeschichtungen ausgewaschen werden. Seit ca. zehn Jahren werden die Wirkstoffe zunehmend auch in verkapselter Form eingesetzt. In einem einjährigen Freilandversuch wurde die Auswaschung der Wirkstoffe Terbutryn (2‐Methylthio‐4‐tert‐butylamino‐1,3,5‐triazin), Diuron (DCMU, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea), IPBC (3‐Iodoprop‐2‐ynyl‐N‐butylcarbamat), OIT (2‐n‐Octyl‐isothiazolin‐3‐on) und DCOIT (4, 5‐Di‐chloro‐2‐n‐octyl‐isothiazolin‐3‐on) sowohl in freier als auch in verkapselter Form untersucht. Es zeigte sich, dass, eingesetzt in einem hoch wasserabweisenden Putzsystem, eine in ihrer Stärke an den jeweiligen Wirkstoff angepasste Verkapselung die Auswaschung deutlich – um bis zu 85 % bei Diuron – reduziert.

Release of biocides from hydrophobic façade coatings: encapsulated vs. non‐capsulated biocide systems. Due to driving rain biocidal active substances, which prevent or delay the overgrow of façades with algae and fungi, can be leached out of the facade coatings. For the past 10 years encapsulated active substances are increasingly used. During a one year field trial the leaching of the substances Terbutryn (2‐Methylthio‐4‐tert‐butylamino‐1,3,5‐triazine), Diuron (DCMU, 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea), IPBC (3‐Iodoprop‐2‐ynyl‐N‐butylcarbamate), OIT (2‐n‐Octyl‐isothiazolin‐3‐one) and DCOIT (4, 5‐Di‐chloro‐2‐n‐octyl‐isothiazolin‐3‐one) have been investigated in capsulated and non‐capsulated form. It shows that a well adjusted rate of encapsulation of the active substances could significantly reduce the release (up to 85 % in case of Diuron) from highly hydrophobic façade coatings.
Energieeffizienz und Wirtschaftlichkeit oberflächennaher Geothermie für das Heizen und Kühlen von Nichtwohngebäuden
Authors: Eicker Ursula , Thumm Felix
Published: February 2012

In der Untersuchung wird die Effizienz oberflächennaher Geothermie Anlagen anhand von fünf Bauprojekten analysiert. Die Messergebnisse werden mit Auslegungsdaten der VDI 4640 verglichen, um die verwendeten Dimensionierungsrichtlinien zu überprüfen. Die messtechnischen Auswertungen der Beispielanlagen zeigen, dass die spezifischen Leistungen der Richtlinie nicht erreicht werden und die jährliche Heiz‐ und Kühlenergie pro Meter Sonde relativ niedrig ist. Um einen wirtschaftlichen Kälte‐ bzw. Wärmepreis zu erreichen, spielt die exakte Dimensionierung eine große Rolle. Wie in den Wirtschaftlichkeitsuntersuchungen gezeigt wird, sind aufgrund der geringen spezifischen Leistungen nur die Anlagen rentabel, die sehr geringe Investitionskosten haben. Eine Laufzeiterhöhung mit möglichst hohen spezifischen Leistungen ist daher von großer Bedeutung, um die oberflächennahen Geothermie möglichst ökologisch und ökonomisch sinnvoll zu nutzen.

Energy efficiency and cost effectiveness of low depth geothermal heating and cooling for non‐residential buildings. In the study the performance of low depth geothermal heat exchangers is analyzed for five building projects. The measurement results are compared with the German standard of the VDI 4640. The analysis shows that the specific power given in the standard is not achieved and the annual heating and cooling energy per meter borehole is quite low. In order to achieve an economic cooling or heating price, the exact dimensioning of the geothermal heat exchanger is a major criterion. As it is shown in the economic studies, only the systems with a very low invest are profitable. An increase of operating hours with a preferably high specific power is vitally important for a viable use of low depth geothermal energy in an ecological and economical way.
Der generalisierte COND‐Algorithmus zur hygrothermischen Bewertung von Konstruktionen
Authors: Nicolai Andreas
Published: February 2012

Mittels des COND‐Berechnungsalgorithmus können eindimensionale Konstruktionsaufbauten hinsichtlich des hygrothermischen Verhaltens in der Kondensationsperiode bewertet werden. In Ergänzung zum Standardverfahren (Glaser) nach DIN 4108‐3 berücksichtigt COND den kapillaren Transport von Kondensat. Damit lässt sich der Feuchteschutznachweis auch für moderne praxisbewährte Innendämmsysteme führen, die nach Glaser nicht nachweisfähig sind. Der Berechnungsalgorithmus wird in der überarbeiteten, allgemeingültigen Form detailliert und vollständig dargestellt und beschrieben. Das Materialmodell und eingeführte Vereinfachungen werden diskutiert. Abschließend werden Einsatzbereiche und Grenzen des Verfahrens erläutert.

With the COND algorithm architects and engineers may evaluate one‐dimensional constructions with respect to their hygrothermal behavior within a condensation period. COND considers, in contrast to the standard method (Glaser‐method) according to DIN 4108‐3, the capillary transport of interstitial condensate. The method allows hygrothermal verification of constructions, including modern internal insulation systems. Such systems, proven to be effective in practice but not verifiable with the Glaser method, may be analyzed and certified with the COND method. The article includes a full and detailed description of this computational algorithm. The paper discusses the material model and introduced simplifications, and concludes with a review on application fields and limits of the method.
Einfluss von Hohlräumen auf die Wärmeleitfähigkeit von ausgewählten Holzwerkstoffen für den Baueinsatz
Authors: Joščák Matúš , Sonderegger Walter , Niemz Peter , Schnider Thomas , Oppikofer Reinhard , Lammar Laura
Published: February 2012

An ausgewählten Holzwerkstoffen (Buchenfurnier, MDF‐ und Spanplatten) wurde der Einfluss des Einbringens von Hohlräumen auf die Wärmeleitfähigkeit untersucht. Für die Versuche wurden die Platten in mehreren Lagen geschichtet (Lagendicke je nach Material 2,7 bis 5 mm) und die Aufbauten variiert, wobei Platten mit und ohne Hohlräume verwendet wurden. Um den Einfluss der Wärmestrahlung in den Hohlräumen zu untersuchen, wurden zusätzlich Aluminiumfolien (geringer Emissionsgrad) eingelegt. Es konnte festgestellt werden, dass durch das Einbringen von Hohlräumen (Volumenanteil ca. 46 %) eine Reduzierung der Wärmeleitfähigkeit um bis zu 51 % erreicht wird. Ein zusätzliches Einlegen von Aluminiumfolie quer zur Wärmestromrichtung reduziert die Wärmeleitfähigkeitswerte nochmals wesentlich (bis zu 64 %) aufgrund der stark reduzierten Wärmestrahlung in den Hohlräumen. Dies ist besonders ausgeprägt bei den Aufbauten mit größeren Hohlraumdicken. Um das Potential des Anbringens von Hohlräumen im Holzbauwesen zu nutzen, wurde ein Vorschlag für ein neues Produkt auf Holzbasis präsentiert.

Influence of the air cavities on thermal conductivity of selected wood based materials and their application for building industry. On selected wood‐based materials (beech veneer, MDF and particle board), the influence of inserting air cavities on the thermal conductivity was investigated. For the tests, the particular boards (board thickness: 2.7 to 5 mm according to the material) were layered in multiple layers by varying the assemblies and using boards with and without cavities. Additionally, aluminium foils (low emissivity) were inserted to investigate the influence of heat radiation in the cavities. It can be stated that inserting air cavities (approximately 46 % of core material) results in a reduction of thermal conductivity up to 51 %. An additional insertion of aluminium foils perpendicular to the direction of heat flow reduces the thermal conductivity once more significantly (up to 64 %) due to a strong reduced heat radiation within the cavities. This is particularly pronounced in the constructions with larger air cavity thicknesses. Additionally, a proposal of a new product based on wood has been presented to develop the potential of inserting cavities for timber construction.
A novel and simple method of production and biophysical characterization of a mini‐membrane protein, Ost4p: A Subunit of yeast oligosaccharyl transferase
Authors: Kumar Amit , Ward Priscilla , Katre Uma V. , Mohanty Smita
Published: February 2012

Asparagine‐linked glycosylation is an essential and highly conserved protein modification reaction. In eukaryotes, oligosaccharyl transferase (OT), a multi‐subunit membrane‐associated enzyme complex, catalyzes this reaction in newly synthesized proteins. In Saccharomyces cerevisiae, OT consists of nine nonidentical membrane proteins. Ost4p, the smallest subunit, bridges the catalytic subunit Stt3p with Ost3p. Mutation of transmembrane residues 18–24 in Ost4p has negative effect on OT activity, disrupts the Stt3p–Ost4p–Ost3p complex, results in temperature‐sensitive phenotype, and hypoglycosylation. Heterologous expression and purification of integral membrane proteins are the bottleneck in membrane protein research. The authors report the cloning, successful overexpression and purification of recombinant Ost4p with a novel but simple method producing milligram quantities of pure protein. GB1 protein was found to be the most suitable tag for the large scale production of Ost4p. The cleavage of Ost4p conveniently leaves GB1 protein in solution eliminating further purification. The precipitated pure Ost4p is reconstituted in appropriate membrane mimetic. The recombinant protein is highly helical as indicated by the far‐UV CD spectrum. The well‐dispersed heteronuclear single quantum coherence spectrum indicates that this minimembrane protein is well‐folded. The successful production of pure recombinant Ost4p with a novel yet simple method may have important ramification for the production of other membrane proteins. © 2012 Wiley Periodicals, Inc. Biopolymers 97:499–507, 2012.
Peptide nanotube composed of cyclic tetra‐β‐peptide having polydiacetylene
Authors: Ishihara Yusuke , Kimura Shunsaku
Published: February 2012

A cyclic tetra‐β‐peptide composed of three β‐alanine residues and a L‐β‐homolysine residue having 10,12‐pentacosadiynoic amide at the side chain was synthesized. The cyclic tetra‐β‐peptide formed peptide nanotubes in CDCl3. The diacetylene units along the peptide nanotubes were polymerized by UV irradiation to obtain peptide nanotubes with polydiacetylene along the nanotube. TEM and AFM observations of the polymerized cyclic tetra‐β‐peptides confirmed that the peptide nanotube structure was preserved after polymerization. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 155–160, 2012.
Intraoperative, postoperative and reoperative problems with ileoanal pouches
Authors: Sagar P M , Pemberton J H
Published: February 2012

Background

Proctocolectomy with ileal pouch-anal anastomosis (IPAA) has been developed and refined since its introduction in the late 1970s. Nonetheless, it is a procedure associated with significant morbidity. The aim of this review was to provide a structured approach to the challenges that surgeons and physicians encounter in the management of intraoperative, postoperative and reoperative problems associated with ileoanal pouches.

Methods

The review was based on relevant studies identified from an electronic search of MEDLINE, Embase and PubMed databases from 1975 to April 2011. There were no language or publication year restrictions. Original references in published articles were reviewed.

Results

Although the majority of patients experience long-term success with an ileoanal pouch, significant morbidity surrounds IPAA. Surgical intervention is often critical to achieve optimal control of the situation.

Conclusion

A structured management plan will minimize the adverse consequences of the problems associated with pouches.
A new method of spermatic cord mobilization in herniorrhaphy
Authors: Tan Yi‐Hong , Xiao Yu‐Gen , Du Guo‐Neng , Liu Jian‐Wen , Li Min , Xu Li‐Xiao‐Zi , Qiu Wan‐Shou
Published: February 2012

Spermatic cord mobilization is a routine part of inguinal hernia repair, but the method of cord mobilization varies among surgeons. This study establishes an anatomic plane for spermatic cord mobilization. We studied the anatomy of the superficial cremasteric fascia in 105 male patients during herniorrhaphy for primary inguinal hernias. The mean patient age was 44.8 (18–71) years and mean body mass index was 24.1 kg/m2 (21.5–27.1 kg/m2). The two layers of the superficial cremasteric fascia between the spermatic cord and the inguinal falx were incised to mobilize the cord. We found that spermatic cord mobilization during herniorrhaphy can be easily approached through an anatomic plane between the spermatic cord and the conjoined tendon with subsequent division of the superficial cremasteric fascia. None of the patients experienced any hemorrhage or nerve injury during cord mobilization. We found this method to be both safe and easy to learn. Clin. Anat. 25:1074–1079, 2012. © 2012 Wiley Periodicals, Inc.
Versatile Effects of Aurone Structure on Mushroom Tyrosinase Activity
Authors: Dubois Carole , Haudecoeur Romain , Orio Maylis , Belle Catherine , Bochot Constance , Boumendjel Ahcène , Hardré Renaud , Jamet Hélène , Réglier Marius
Published: February 2012

Elucidation of the binding modes of Ty inhibitors is an important step for in‐depth studies on how to regulate tyrosinase activity. In this paper we highlight the extraordinarily versatile effects of the aurone structure on mushroom Ty activity. Depending on the position of the OH group on the B‐ring, aurones can behave either as substrates or as hyperbolic activators. The synthesis of a hybrid aurone through combination of an aurone moiety with HOPNO (2‐hydroxypyridine N‐oxide), a good metal chelate, led us to a new, efficient, mixed inhibitor for mushroom tyrosinase. Another important feature pointed out by our study is the presence of more than one site for aurone compounds on mushroom tyrosinase. Because study of the binding of the hybrid aurone was difficult to perform with the enzyme, we undertook binding studies with tyrosinase functional models in order to elucidate the binding mode (chelating vs. bridging) on a dicopper(II) center. Use of EPR combined with theoretical DFT calculations allowed us to propose a preferred chelating mode for the interaction of the hybrid aurone with a dicopper(II) center.
Oxygen Electroreduction Activity and X‐Ray Photoelectron Spectroscopy of Platinum and Early Transition Metal Alloys
Authors: Stephens Ifan E. L. , Bondarenko Alexander S. , Bech Lone , Chorkendorff Ib
Published: February 2012

The oxygen reduction reaction (ORR) was studied experimentally on sputter‐cleaned, polycrystalline electrodes of Pt3Y, Pt5Y, Pt2Y, Pt3Sc, Pt3Hf, Pt3Zr and Pt under conditions relevant for low‐temperature fuel cells. The surfaces were characterised in situ by means of electrochemical methods and ex situ under ultrahigh vacuum conditions. The ORR activity was established in an electrochemical cell containing 0.1 M HClO4 by use of a rotating ring disk electrode assembly. The surface composition was characterised before and after the electrochemical measurements by using angle‐resolved X‐ray photoelectron spectroscopy. The ORR activity of the electrodes increased in the following order: Pt2Y≈Pt3Zr≈Pt≈<Pt3Hf<Pt3Sc≪Pt5Y<Pt3Y. At 23 °C, the most active catalyst, Pt3Y, exhibited a six‐ to ninefold improvement in activity over Pt in the potential range 0.9–0.87 V with respect to a reversible hydrogen electrode. Over the same potential range at 60 °C, Pt3Y exhibited a four‐ to fivefold improvement in activity over Pt. The angle‐resolved X‐ray photoelectron spectroscopy analyses show that Pt3Y and Pt5Y formed a Pt overlayer under ORR conditions. In contrast, the surfaces of Pt3Hf and Pt3Zr comprised a mixture of Pt and HfOx or ZrOx, respectively, which explained their poor performance.
Metal–Organic Frameworks Constructed from Versatile [WS4Cux]x−2 Units: Micropores in Highly Interpenetrated Systems
Authors: Lu Zhen‐Zhong , Zhang Rui , Pan Zhao‐Rui , Li Yi‐Zhi , Guo Zi‐Jian , Zheng He‐Gen
Published: February 2012

Five metal–organic frameworks (MOFs) formed by [WS4Cux]x−2 secondary building units (SBUs) and multi‐pyridyl ligands are presented. The [WS4Cux]x−2 SBUs function as network vertexes showing various geometries and connectivities. Compound 1 contains one‐dimensional channels formed in fourfold interpenetrating diamondoid networks with a hexanuclear [WS4Cu5]3+ unit as SBU, which shows square‐pyramidal geometry and acts as a tetrahedral node. Compound 2 contains brick‐wall‐like layer also with a hexanuclear [WS4Cu5]3+ unit as SBU. The [WS4Cu5]3+ unit in 2 is a new type of [WS4Cux]x−2 cluster unit in which the five Cu+ ions are in one plane with the W atom, forming a planar unit. Compound 3 shows a nanotubular structure with a pentanuclear [WS4Cu4]2+ unit as SBU, which is saddle‐shaped and acts as a tetrahedral node. Compound 4 contains large cages formed between two interpenetrated (10,3)‐a networks also with a pentanuclear [WS4Cu4]2+ unit acting as a triangular node. The [WS4Cu4]2+ unit in 4 is isomeric to that in 3 and first observed in a MOF. Compound 5 contains zigzag chains with a tetrahedral [WS4Cu3]+ unit as SBU, which acts as a V‐shaped connector. The influence of synthesis conditions including temperature, ligand, anions of CuI salts, and the ratio of [NH4]2WS4 to CuI salt on the formation of these [WS4Cux]x−2‐based MOFs were also studied. Porous MOF 3 is stable upon removal and exchange of the solvent guests, and when accommodating different solvent molecules, it exhibits specific colors depending on the polarity of incorporated solvent, that is, it shows a rare solvatochromic effect and has interesting prospects in sensing applications.
Total Synthesis of Laulimalide: Assembly of the Fragments and Completion of the Synthesis of the Natural Product and a Potent Analogue
Authors: Trost Barry M. , Amans Dominique , Seganish W. Michael , Chung Cheol K.
Published: February 2012

Herein, we present a full account of our efforts to couple the northern and the southern building blocks, the synthesis of which were described in the preceding paper, along with the modifications required to ultimately lead to a successful synthesis of laulimalide. Key highlights include an exceptionally efficient and atom‐economical intramolecular ruthenium‐catalyzed alkene–alkyne coupling to build the macrocycle, followed by a highly stereoselective 1,3‐allylic isomerization promoted by a rhenium complex. Interestingly, the designed synthetic route also allowed us to prepare an analogue of the natural product that possesses significant cytotoxic activity. We also report a second generation route that provides a more concise synthesis of the natural product.
Dipeptidyl Peptidase IV (DPPIV/CD26)‐Based Prodrugs of Hydroxy‐Containing Drugs
Authors: Diez‐Torrubia Alberto , Cabrera Silvia , Lambeir Anne‐Marie , Balzarini Jan , Camarasa María‐José , Velázquez Sonsoles
Published: February 2012

We previously described a novel prodrug approach in which a di‐ or tetrapeptide moiety is linked to a wide variety of amine‐containing drugs through an amide bond, which is specifically cleaved by dipeptidyl peptidase IV (DPPIV/CD26) activity. Herein we report the application of this prodrug approach to a variety of hydroxy‐containing drugs (primary, secondary, tertiary, or aromatic hydroxy groups). We designed and studied tripartite prodrugs containing a dipeptide moiety (cleavable by DPPIV/CD26) and a valine as a hetero‐bifunctional connector to link the dipeptide to the hydroxy group of the drug through a metabolically labile ester bond. The hydroxy‐containing prodrugs showed various susceptibilities to hydrolysis by DPPIV/CD26 and serum, depending on the nature of the compound. Prodrugs of compounds containing a primary hydroxy group (as in didanosine) or a hydroxy moiety on an aromatic entity (as in acetaminophen) were most efficiently converted. In contrast, a tertiary hydroxy group was much less susceptible to conversion into its parent drug by DPPIV/CD26 or serum. A number of the prodrugs showed remarkable increases in water solubility relative to their parent drugs.
Discovery of [(2R,5R)‐5‐{[(5‐Fluoropyridin‐2‐yl)oxy]methyl}‐2‐methylpiperidin‐1‐yl][5‐methyl‐2‐(pyrimidin‐2‐yl)phenyl]methanone (MK‐6096): A Dual Orexin Receptor Antagonist with Potent Sleep‐Promoting Properties
Authors: Coleman Paul J. , Schreier John D. , Cox Christopher D. , Breslin Michael J. , Whitman David B. , Bogusky Michael J. , McGaughey Georgia B. , Bednar Rodney A. , Lemaire Wei , Doran Scott M. , Fox Steven V. , Garson Susan L. , Gotter Anthony L. , Harrell C. Meacham , Reiss Duane R. , Cabalu Tamara D. , Cui Donghui , Prueksaritanont Thomayant , Stevens Joanne , Tannenbaum Pamela L. , Ball Richard G. , Stellabott Joyce , Young Steven D. , Hartman George D. , Winrow Christopher J. , Renger John J.
Published: February 2012

Insomnia is a common disorder that can be comorbid with other physical and psychological illnesses. Traditional management of insomnia relies on general central nervous system (CNS) suppression using GABA modulators. Many of these agents fail to meet patient needs with respect to sleep onset, maintenance, and next‐day residual effects and have issues related to tolerance, memory disturbances, and balance. Orexin neuropeptides are central regulators of wakefulness, and orexin antagonism has been identified as a novel mechanism for treating insomnia with clinical proof of concept. Herein we describe the discovery of a series of α‐methylpiperidine carboxamide dual orexin 1 and orexin 2 receptor (OX1R/OX2R) antagonists (DORAs). The design of these molecules was inspired by earlier work from this laboratory in understanding preferred conformational properties for potent orexin receptor binding. Minimization of 1,3‐allylic strain interactions was used as a design principle to synthesize 2,5‐disubstituted piperidine carboxamides with axially oriented substituents including DORA 28. DORA 28 (MK‐6096) has exceptional in vivo activity in preclinical sleep models, and has advanced into phase II clinical trials for the treatment of insomnia.
A DDS‐based middleware for quality‐of‐service and high‐performance networked robotics
Authors: Cruz Jesús Martínez , Romero‐Garcés Adrián , Rubio Juan Pedro Bandera , Robles Rebeca Marfil , Rubio Antonio Bandera
Published: February 2012

Social robots must adapt to dynamic environments, human interaction partners and challenging new stringent tasks. Their inner software is usually distributed and should be designed and deployed carefully because slight changes in the robot's requirements can have an important impact not only on the existing source code but also on the resulting performance at run‐time. This paper proposes an implementation of this inner software using a new lightweight middleware for networked robotics called Nerve. The principal novelty this middleware has with respect to other state‐of‐the‐art approaches is that it guarantees both scalability and QoS, which are key requirements for real‐time robotics software. The benefits of Nerve have been proved through its use in two key components of the cognitive system of a social robot: (i) the visual attention mechanism, used to extract relevant data from perceived images; and (ii) a robot learning by imitation control architecture that allows the social robot to be taught by people using natural demonstrations (i.e. using the same communication channels that would be used to teach people). Nerve makes use of existing patterns for networked applications together with the recent Data Distribution Service specification, which is a publish/subscribe standard for real‐time and distributed systems that provides a wide set of QoS policies. In this paper, these different QoS policies have been applied carefully to achieve the best performance of the target robot. Copyright © 2012 John Wiley & Sons, Ltd.
One‐Dimensional 3d–3d–4f Trimetallic Assemblies Consisting of CuII2LnIII Trinuclear Complexes and Hexacyanometallate
Authors: Shiga Takuya , Mishima Akio , Sugimoto Kunihisa , Ōkawa Hisashi , Oshio Hiroki , Ohba Masaaki
Published: February 2012

A series of one‐dimensional heterotrimetallic assemblies, [Cu2Ln(L)2(H2O)4][M(CN)6]·nH2O [Ln = Gd, M = Co (1), Fe (2), Cr (3), and Ln = La, M = Co (4), Fe (5), Cr (6)], were prepared by the reaction of a Cu2Ln precursor complex, [Cu2Ln(L)2(NO3)3], with K3[M(CN)6] in water. All of the assemblies were isomorphous and formed a 1D zigzag chain, in which the [Cu2Ln(L)2(H2O)4]3+ and [M(CN)6]3– units were alternately positioned and were linked in a Cu–NC–M–CN–Cu manner. Compound 1 showed magnetic behaviour similar to that of the discrete precursor complex, [Cu2Gd(L)2(NO3)3], owing to the diamagnetic nature of the [CoIII(CN)6]3– unit. In the case of 2, a simple summation of the magnetic behaviour of the [Cu2Gd(L)2(H2O)4]3+ and [Fe(CN)6]3– units was observed, whereas ferromagnetic interactions were found to be operative between the Cu2+ and Cr3+ ions in compound 3. The same magnetic interactions between Cu2+ and M3+ were confirmed in compounds 4 to 6, which included the diamagnetic La3+ ion. The differences in the magnetic behaviours of 2 and 3 can be explained by the overlap of the d(Cu)–pπ(CN) orbitals in the bent Cu–N≡C linkage and the spin‐density on the cyanide nitrogen of the [Cr(CN)6]3– unit.