bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of CO2-induced changes in seawater carbonate chemistry speciation on Coccolithus braarudii: a conceptual model of coccolithophorid sensitivities
Authors: Krug S. A. , Schulz K. G. , Riebesell U.
Published: December 2010

Abstract. Ocean acidification and associated shifts in carbonate chemistry speciation induced by increasing levels of atmospheric carbon dioxide (CO2) have the potential to impact marine biota in various ways. The process of biogenic calcification, for instance, is usually shown to be negatively affected. In coccolithophores, an important group of pelagic calcifiers, changes in cellular calcification rates in response to changing ocean carbonate chemistry appear to differ among species. By applying a wider CO2 range we show that a species previously reported insensitive to seawater acidification, Coccolithus braarudii, responds both in terms of calcification and photosynthesis, although at higher thresholds. Thus, observed differences between species seem to be related to individual sensitivities while the underlying mechanisms could be the same. On this basis we develop a conceptual model of coccolithophorid calcification and photosynthesis in response to CO2-induced changes in seawater carbonate chemistry speciation.
A Multivariate Probit Analysis of Willingness to Pay for Cave Conservation: A Case Study of Yanchep National Park, Western Australia
Authors: Tapsuwan Sorada , Burton Michael , Perriam James
Published: November 2010

This study employed the double-bounded dichotomous choice contingent valuation technique along with factor analysis to estimate visitors' willingness to pay (WTP) for the Yanchep Caves Recovery Project (YCRP). Two payment vehicles were used to elicit WTP: park entry fee and cave entry fee. The main contribution of this paper is the joint estimation of the two payment vehicles using the multivariate probit model by allowing the error terms of the two models to be correlated. Emphasis was given to testing whether parameters of the two bid levels should be constrained and to overcoming anchoring bias. The estimated median WTP for cave and park entry fees when accounting for anchoring effect and constrained parameters was AU$10.20 and AU$16.40, respectively. Without correcting for the anchoring effect, the WTP probability is overestimated for lower bids and underestimated for higher bids.
Anomaly in Spanish Tourist Sensitivity to Price
Authors: Nicolau Juan L.
Published: November 2010

The literature suggests that the effect of price on destination choice can be either positive or negative and income is considered an important determinant of tourist decisions, so that tourism products are thought to behave like ‘normal goods’. Given that studies have paid little attention to the relationship between income and sensitivity to price, this paper analyses the relationship between income and tourists' sensitivities to price. The author identifies and measures these sensitivities – individual by individual – from real choices made by tourists: that is, tourist sensitivity to price is estimated for each individual by observing the destination he or she actually selects. The empirical application is carried out on a sample of 2,127 individuals and the operative formalization used to estimate individual sensitivities to price follows a random coefficient logit model. To detect how the sensitivities relate to income, a regression analysis is employed. The results show an anomalous relationship: income levels moderate tourist sensitivity to price such that increases in the first levels of income reduce the negative effect of price (as expected), but there is a ‘saturation point’ – that is, beyond a threshold, tourist sensitivity to price increases again (the negative effect of price reappears) – against expectations for these high-income earners.
Research Note: Seasonality in Sicilian Tourism Demand – An Exploratory Study
Authors: Volo Serena
Published: November 2010

This paper addresses the need for an understanding of the evolution of international and domestic tourism in Sicily, in particular, the relationship between seasonality patterns and the development of the tourism sector. Annual tourist arrivals and overnight stays data were studied using univariate methods. It is concluded that Italian and international tourism demand differ significantly and that seasonality has been changing somewhat over time, creating a challenge to economic planners and marketers.
Research Note: Testing the Tourism-Led Growth Hypothesis for Singapore – An Empirical Investigation from Bounds Test to Cointegration and Granger Causality Tests
Authors: Katircioğlu Salih
Published: November 2010

This paper empirically investigates the tourism-led growth (TLG) hypothesis in the case of Singapore by employing the bounds test for cointegration, error correction models and Granger causality tests using annual data from 1960 to 2007. The results confirm the existence of a long-term equilibrium relationship between international tourism and economic growth in the case of Singapore; real income growth converges significantly toward its long-term equilibrium level of 51.4% in the TLG model. The major finding of this study is that the TLG hypothesis is confirmed for the Singaporean economy in the long term as a result of conditional Granger causality tests.
Research Note: The Tourism–Growth Nexus in Croatia
Authors: Payne James E. , Mervar Andrea
Published: November 2010

This empirical study examines the tourism-led growth hypothesis for Croatia using quarterly data from 2000:1 to 2008:3. The Toda– Yamamoto long-run causality tests reveal positive unidirectional causality from real GDP to international tourism revenues, as well as positive unidirectional causality from real GDP to the real effective exchange rate. Thus, the results lend support for the economic-driven tourism growth hypothesis.
Measuring Hotel Performance Using the Integer Dea Model
Authors: Wu Jie , Liang Liang , Song Haiyan
Published: November 2010

This study discusses the comparative efficiency of hotels using integer data envelopment analysis (IDEA), which is an extension to the traditional DEA models. This model is particularly useful when the integer input or output data are used in the evaluation of hotel performance. Specifically, IDEA can identify more appropriate and feasible input and output targets than the traditional DEA models. The empirical analysis of IDEA is carried out based on a data set related to 23 tourist hotels in Taipei. The contributions and managerial implications for efficiency improvement of this study are also presented.
Assessing the Economic Impact of Culture in English Market Towns: A Causal Chain Approach
Authors: Young Robert , Young Anita Fernandez , Parkin Jennifer , Diamond Abigail
Published: November 2010

In assessing the economic impact of a cultural event or attraction, the number of visits caused by the event or attraction is the pivotal variable. In the instance of many visitors, the causal impact is neither absent nor complete, but partial. The authors develop a method of assessing directly the aggregate causal impact of a cultural event or attraction and apply this in four case studies of culture in market towns. There emerges a pattern in the way economic impact comes about.
Tourism and Openness to Trade in Singapore: Evidence Using Aggregate and Country-Level Data
Authors: Wong Koi Nyen , Tang Tuck Cheong
Published: November 2010

Tourism has been identified as one of the key growth sectors in Singapore's economy. Given that the city state has been recognized as one of the most open economies in the world, this study explores the causality relationships between tourism and openness to trade, using aggregated variables – total visitor arrivals and data on trade components (merchandise and services) – and their respective disaggregated data by country for each of Singapore's top five trading partners – Malaysia, China, the USA, Japan and South Korea. The study shows bidirectional causality between international visitor arrivals in Singapore and openness to merchandise trade. However, the causality pattern varies among Singapore's major trading partners if country-level data are used. The overall findings imply that further trade liberalization with Singapore's major trading partners may not necessarily encourage visitor arrivals from those countries, but can be seen as an important catalyst for the growth and development of the tourism sector. Conversely, an increase in tourism activities could also encourage the host country to open itself to more international trade. Furthermore, it is imperative to liberalize the service sector in Singapore to facilitate greater openness in merchandise trade, given that a large proportion of services constitutes the goods trade.
Measuring Returns on Hong Kong's Tourism Marketing Expenditure
Authors: Zhang Hanqin Qiu , Kulendran Nada , Song Haiyan
Published: November 2010

The objective of this study is to estimate the per dollar return on tourism marketing expenditure by the Hong Kong Tourism Board in major tourism markets, based on the dynamic modelling approach and cost-effectiveness ratios. The study finds that the estimated cost-effectiveness ratios for the major inbound tourism markets of Australia, China, the USA, the UK, South Korea and Singapore are positive, and that the estimated per dollar returns on tourism marketing expenditure are 9.5:1, 15:1, 2.5:1, 2.8:1, 7.2:1 and 8.7:1, respectively. The results suggest that in order to increase the tourist receipts from these markets, it is necessary to develop different and specific marketing strategies to attract tourists from each market.
Estudio ecológico del swa (Carapa guianensis Aubl, Meliaceae) en tres comunidades del río Patuca, Honduras
Authors: Díaz Arita Laura
Published: December 2010

Carapa guianensis, swa (nombre en miskito) o cedro macho (nombre en español), es una especie nativa de los bosques húmedos tropicales de América. Su madera es muy útil y apreciada por los indígenas; de sus semillas se extrae un producto forestal no maderable llamado aceite de swa, que es medicinal y cosmético; es exportado por los indígenas a una empresa de productos para el cabello en Canadá. El estudio ecológico se llevó a cabo en las comunidades de Wampusirpi, Kurhpa y Krausirpi, en las vegas del río Patuca. Para ello, se midieron árboles de swa y árboles no swa que estaban dentro del transecto, para calcular variables ecológicas y estimar la capacidad de extracción de las semillas para la extracción del aceite y, con esta información, poder determinar las actividades de manejo para el uso sostenible, y evitar así, un futuro desequilibrio ecológico. Se entrevistaron a 30 productores de aceite para conocer la percepción ecológica que tienen acerca del recurso. En base a los altos resultados obtenidos en los transectos, sobre todo en la dominancia y el índice de valor de importancia de los árboles de swa medidos, se recomienda una extracción del 70% de las semillas que están en el suelo -cálculo que se puede hacer al tanteo-, ya que el 30% restante es necesario para la regeneración natural de los árboles de swa y la alimentación de animales silvestres.Palabras clave: Aceite de swa, agroforestal, dominancia, extracción, índice de valor de importancia, producto forestal no maderable, regeneración natural.DOI: http://dx.doi.org/10.5377/ceiba.v50i1.189
Gestión y Administración Forestal Post-huracán Félix
Authors: Wilson Harold
Published: December 2010

DOI: 10.5377/wani.v58i0.202Wani No.58 2009 pp.22-26
El polo de desarrollo Lakia Tara en Tasba Raya y Sahsa
Authors: Martínez Benigno
Published: December 2010

DOI: 10.5377/wani.v58i0.207Wani No.58 2009 pp.37
Restauración ecológica a través de procesos de sucesión secundaria. El caso de bosques impactados por huracanes
Authors: Carrera Fernando
Published: December 2010

DOI: 10.5377/wani.v58i0.212Wani No.58 2009 pp.58-62
Conclusiones del foro
Authors: Canales Jorge
Published: December 2010

DOI: 10.5377/wani.v58i0.213Wani No.58 2009 pp.72-73
High‐Throughput Screening of Viral Entry Inhibitors Using Pseudotyped Virus
Authors: Basu Arnab , Mills Debra M. , Bowlin Terry L.
Published: December 2010

Virus entry into a host cell is an attractive target for therapy because propagation of virus can be blocked at an early stage, minimizing chances for the virus to acquire drug resistance. Anti‐infective drug discovery for BSL‐4 viruses like Ebola or Lassa hemorrhagic fever virus presents challenges due to the requirement for a BSL‐4 laboratory containment facility. Pseudotyped viruses provide a surrogate model in which the native envelope glycoprotein of a BSL‐2 level virus (e.g., vesicular stomatitis virus) is replaced with envelope glycoprotein of a foreign BSL‐4 virus (e.g., Ebola virus). Because the envelope glycoprotein determines interaction of virus with its cellular receptors, pseudotyped viruses can mimic the viral entry process of the original virus. Moreover, they are competent for only a single cycle of infection, and therefore can be used in BSL‐2 facilities. Pseudotyped viruses have been used in high‐throughput screening of entry inhibitors for a number of BSL‐4 level viruses. This unit includes protocols for preparing pseudotyped viruses using lentiviral vectors and use of pseudotyped viruses for high‐throughput screening of viral entry inhibitors.Curr. Protoc. Pharmacol. 51:13B.3.1‐13B.3.17. © 2010 by John Wiley & Sons, Inc.
Multicomponent Synthesis of 1,2,3‐Triazoles in Water Catalyzed by Copper Nanoparticles on Activated Carbon
Authors: Alonso Francisco , Moglie Yanina , Radivoy Gabriel , Yus Miguel
Published: December 2010

Copper nanoparticles on activated carbon have been found to effectively catalyze the multicomponent synthesis of 1,2,3‐triazoles from different azide precursors, such as organic halides, diazonium salts, anilines and epoxides in water. The first one‐pot transformation of an olefin into a triazole is also described. The catalyst is easy to prepare, very versatile and reusable at a low copper loading.
Influence of incorporation of ZnO nanoparticles and biaxial orientation on mechanical and oxygen barrier properties of polypropylene films for food packaging applications
Authors: Lepot N. , Van Bael M. K. , Van den Rul H. , D'Haen J. , Peeters R. , Franco D. , Mullens J.
Published: December 2010

In this work, the effect of zinc oxide (ZnO) concentration and shape on processing and properties of new biaxially oriented polypropylene (BOPP)‐ZnO nanocomposites was studied. The use of spherical nanoparticles and nanorods was expected to differently influence the properties of the final material. Films of isotactic polypropylene prepared with different ZnO incorporation were biaxially oriented under conditions of temperature and strain rate that were similar to those encountered in a commercial film process. Scanning electron microscopy analysis was performed to visualize the dispersion degree of the ZnO nanoparticles in the polymer matrix and to observe the surface and the orientation of the elongated nanoparticles. Furthermore, the prepared ZnO‐BOPP nanocomposites were evaluated for both mechanical and oxygen barrier property enhancement. A good combination of mechanical and oxygen barrier properties was obtained for the ZnO‐BOPP films. This result makes the ZnO‐BOPP nanocomposite a proper material for applications such as food packaging. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis of chitosan‐poly(Acrylic Acid) complex particles by dispersion polymerization and their applications in ph buffering and drug release
Authors: Chuang Chung‐Yang , Chiu Wen‐Yen , Don Trong‐Ming
Published: December 2010

This research prepared polyelectrolyte complex particles of chitosan‐poly(acrylic acid) (CS‐PAA) through polymerization of acrylic acid (AA) in the presence of chitosan (CS). The prepared CS‐PAA complex particles had positive zeta potential and dispersed very well in the aqueous solution. Structure and morphology of complex particles were investigated with the changes in the feeding molar ratio of glucosamine unit in CS to AA monomer. It was found at a molar ratio of 1.0/1.1, a hollow structure in complex particles was observed after polymerization. From solid state 13C‐NMR and FTIR analyses, the results confirmed that CS‐co‐PAA copolymer was also produced during polymerization in addition to the PAA homopolymer, and both constituted in the structure of complex particles. The synthesized complex particles were environmentally sensitive in which their mean diameter could change with the pH value of medium. Moreover, the complex particles showed a continuous release of the encapsulated doxycycline hyclate up to 8 days. These complex particles with environmentally sensitive properties are expected to be utilized in the hydrophilic drug delivery system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology, order, light transmittance, and water vapor permeability of aluminum‐coated polypropylene zeolite composite films
Authors: Balköse Devrim , Oguz Kaan , Ozyuzer Lutfi , Tari Suleyman , Arkis Esen , Omurlu Filiz Ozmıhçı
Published: December 2010

In this study, the polypropylene–zeolite composite films having 2–6 wt % natural zeolite were coated with a thin film of aluminum (Al) by magnetron sputtering, and the contribution of the Al coating on film properties was investigated. The samples were characterized by EDX, X‐ray diffraction, SEM, AFM, UV–visible spectroscopy, and water vapor permeation analyses. The surface of the films coated with a smooth Al film having 98–131 nm thickness. EDX revealed that Al percentage on the surface appeared to be as 8–10 wt % indicating contribution of polymer surface under Al film to analysis. XRD analysis showed that the grain size of Al at the surface was 22–29 nm. The surface roughness increased after Al‐coating process. The transmission of coated films was very low for both UV and visible regions of the light spectrum. Permeation analysis indicated that water vapor permeation was lower for Al‐coated material. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polymerization of acrylated epoxidized soybean oil with phenol furfural resins via repeated forward and retro diels–alder reactions
Authors: Çaylı Gökhan , Küsefoğlu Selim
Published: December 2010

In this work, the Diels–Alder reaction between the acrylate groups of acrylated epoxidized soybean oil and the furan rings of p‐tertiary butyl phenol furfural resin (TBPF) is described. The reaction was carried out at 110°C in presence of FeCl3 catalyst, and tough polymers were obtained in 1 h. Surprisingly, samples that were heated and cooled 5, 10, and 20 times to 140°C and room temperature had better mechanical properties than samples that were kept at 140°C for the same total duration. This unexpected behavior is attributed to a series of forward and retro Diels–Alder reactions between the functional groups. To prove this hypothesis, a model reaction between TBPF and n‐butyl acrylate was studied. At 100°C, 1H‐nuclear magnetic resonance signals of the furan ring protons disappeared, only to reappear at 140°C. Thermogravimetric analysis of the adduct showed a weight loss at 140–150°C, which was in quantitative agreement with the amount of butyl acrylate. Infrared analysis showed that furan rings were not completely consumed by extended heating at 110°C. After five heating and cooling cycles of much shorter duration at 140°C, the furan absorption in the infrared disappeared. The storage modulus of acrylated epoxidized soybean oil‐TBPF samples after 20 heating cycles was 1.15 GPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of blend composition and structure on biodegradation of starch/ecoflex‐filled polyethylene films
Authors: Shi Bo , Shlepr Mike , Palfery Doris
Published: December 2010

A method to blend starches and polyethylene, and thus improve the environmental footprint, was investigated. Unlike traditional methods that utilize compatibilizers or rely on reactive extrusion to achieve the desired material compatibility, a high amylose starch, such as Gelose 80, was mixed with native starch, converted to thermoplastic starch, and compounded with Ecoflex and polyethylene. Films showed good integrity and were evaluated for mechanical properties, anaerobic biodegradability, and structure changes both before and after anaerobic sludge digestion. Mechanical properties were sufficient that these films might be utilized in a number of applications but were not recommended as a sustainable solution. Biodegradation was below the theoretical maximum, was not a linear function of the amount of biodegradable materials incorporated in the films, and was depressed further as the proportion of polyethylene increased due to an encapsulation effect. Structural evaluation showed the components of the blends remained as separate phases and the structure of the Gelose 80 was reminiscent of interphase material. Biodegradation yield appeared to be principally driven by connectivity of the starches within the films to the anaerobic sludge digestion environment. Recommendations for additional studies were given. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Surface characteristics of poly(γ‐alkyl α l‐glutamate)s with different alkyl groups
Authors: Shao Lin‐Jun , Wu Jian , Liu Zhen‐Mei , Xu Zhi‐Kang
Published: December 2010

A series of poly(γ‐alkyl α L‐glutamate)s with different alkyl groups were synthesized by the ring opening polymerization of corresponding α‐amino acid N‐carboxyanhydrides. The characteristics of these polyglutamate surfaces were evaluated by attenuated total reflectance Fourier transform infrared spectroscopy spectra, water contact angle, water absorption, protein adsorption, and platelet adhesion measurements. Changing the length of the alkyl side chain provides a unique opportunity to study the influence of carbon number in the alkyl group on the surface properties of the polyglutamates. Water contact angle and water absorption data show that the hydrophilicity of these polyglutamate surfaces decreases with the increasing of methylene in the alkyl group. Protein adsorption on these polyglutamate surfaces increases with the enhancing of surface hydrophobicity. However, the changes in platelets adhesion could be attributed to the hydrophilicity/hydrophobicity of the polyglutamates and the specific effect of alkyl group. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of linear low‐density polyethylene/dickite nanocomposites prepared by the direct melt blending of linear low‐density polyethylene with exfoliated dickite
Authors: Xue Bing , Zhang Peiping , Jiang Yinshan , Sun Mengmeng , Liu Darui , Yu Lixin
Published: December 2010

Dickite particles were exfoliated by the thermal decomposition of molecular urea in the interlayer of dickite. The exfoliated dickite (ED) was composed with linear low‐density polyethylene (LLDPE) to prepare a novel LLDPE/dickite nanocomposite (LDN‐5). X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to evaluate the exfoliation effect. FTIR spectra showed that the inner‐surface hydroxyls of dickite decreased because of the sufficient exfoliation of the dickite layers. The 001 diffraction of dickite in the XRD pattern almost disappeared after exfoliation; this indicated the random orientation of dickite platelets. SEM and TEM micrographs confirmed the effective thermal decomposition of the interlamellar molecular urea ED layers, which resulted in smaller particle sizes and better dispersions of dickite in the resulting LLDPE/dickite composite. The microstructure of LDN‐5 showed that most of the dickite platelets were exfoliated and homogeneously dispersed in the LLDPE; this led to increases in the anticorrosion properties and thermal stabilities of LDN‐5. The results of salt‐spray tests illustrated that the corrosion rate of the iron coupon decreased from 23% (LLDPE packing) to 0.4% (LDN‐5 packing). Moreover, the thermal degradation temperature corresponding to a mass loss of 10% increased from 330°C (pure LLDPE) to 379°C (LDN‐5). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Self‐aggregation behavior of amphiphilic polyaspartamide derivatives containing cholesterol moieties
Authors: Bach Quang Vu , Moon Jong Rok , Jeon Young Sil , Choe Woo‐Seok , Kim Ji‐Heung
Published: December 2010

Biodegradable amphiphilic copolymers were successfully synthesized by the conjugation of various densities of hydrophobic biocompatible cholesterol (Chol) moieties onto poly(2‐hydroxyethyl aspartamide) and poly(N‐isopropylaminoethyl‐co‐2‐hydroxyethyl aspartamide). These were obtained from polysuccinimde, the thermal polycondensation product of L‐aspartic acid, via a ring‐opening reaction with multifunctional pendant groups, including ethanolamine and N‐isopropylethylenediamine (NIPEDA). Copolymers containing 5–30 mol % Chol showed self‐aggregation behavior in aqueous solution, as evidenced by the dynamic light scattering measurement of their particle size distribution. The average particle size of these copolymers increased linearly with increasing Chol content. Moreover, the presence of secondary amine groups in the poly(2‐hydroxyethyl aspartamide)–NIPEDA system made the conjugation more efficient; however, these also seemed to accelerate the degradation of the copolymers in an aqueous medium. The degradation behavior and pH dependence of the particle size of these copolymers in aqueous solution were also examined. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Quasi‐solid state dye‐sensitized solar cells based on the cross‐linked poly(ethylene glycol) electrolyte with tetraethoxysilane
Authors: Li Pinjiang , Wu Jihuai , Hao Sancun , Lan Zhang , Li Qinghua , Huang Yunfang
Published: December 2010

The cross‐linked poly(ethylene glycol) (PEG‐1000) was prepared by condensation reaction with tetraethoxysilane (TEOS). Using the cross‐linked PEG‐1000 as polymer host, 0.60 M KI and 0.06 M I2 as ionic conductors, an ionic conductivity of the polymer electrolyte was achieved 3.12 mS cm−1. Based on the optimized cross‐linked PEG electrolyte, the best result of the quasi‐solid state dye‐sensitized solar cell (QS‐DSSC) was the short‐circuit photocurrent of 11.87 mA cm−2, the open‐circuit photovoltage of 706 mV, the fill factor of 0.593 and the light‐to‐electricity conversion efficiency of 4.97% at 100 mW cm−2 (AM 1.5). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Investigation of combination of finite element formulation and element type on the accuracy of 3D modeling of polymeric fluid flow in an extrusion die
Authors: Sobhani H. , Razavi‐Nouri M. , Ghoreishy M. H. R.
Published: December 2010

The aim of this work is to investigate the effect of finite element formulation and element type on the accuracy of 3D modeling of generalized Newtonian fluid flow in complex domains. Computer models based on three finite element solution schemes (mixed, continuous, and discrete penalty), and two element types (hexahedral and tetrahedral) in a 3D framework were developed. The well‐known Carreau model was used to reflect the rheological behavior of the fluid. To determine the validity of the developed computer simulations, the flow of two high‐density polyethylene (HDPE) melts with different viscosities through an extrusion die was simulated and compared with experimentally measured data. Comparison showed that the three methods produced nearly the same results with the hexahedral elements. However, continuous penalty method using tetrahedral elements demonstrated an extreme discrepancy from the experimental data. Discrete penalty method was unable to predict secondary variable (pressure) accurately using tetrahedral elements. The best results were obtained by the use of mixed method in conjunction with tetrahedral elements. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation of flexible and transparent SMA films by simple composite with MBS potential for negative birefringence compensator
Authors: Yuan Guo‐Li , Liu Chen , Han Peng , Xie Wei
Published: December 2010

The brittleness of poly(styrene maleic anhydride) (SMA) was improved by compositing with elastic poly(methyl methacrylate‐butadiene‐styrene) (MBS) to develop it into optical film. Transparent and flexible SMA films were prepared, and the flexibility of them was checked by folding endurance test and folding bend. The transparence of SMAMBS films were proved by the transmittance and haze measurements. In actual view, the letters could be clearly observed while they were covered by prepared films. The thermal stability of them was confirmed by DSC and TGA analysis. These physical properties of films are comparable to that of polycarbonate which is widely used as optical film. Besides of these, mechanical and fracture properties of them were found to be also suitable for this purpose. Furthermore, negative birefringence could be obtained by orientationally stretching them. Such results indicate that, films prepared from composites are competent for negative birefringence optical compensator in the field of liquid crystal display. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of RNAi knockdown for E‐complex genes on the silkworm proleg development
Authors: Xiang H. , Li M. W. , Guo J. H. , Jiang J. H. , Huang Y. P.
Published: December 2010

Larvae of many holometabolous insects possess abdominal appendages called prolegs. Lepidoptera larvae have prolegs in the segments A3–A6. Functions of Lepidoptera hox genes on these abdominal appendages development is still a controversial issue. In this article, we report the use of double strand RNA (dsRNA)‐mediated interference (RNAi) to dissect the function of some hox genes, specifically E‐complex genes Ubx, abd‐A, and Abd‐B, in the ventral appendage development of the Lepidoptera silkworm, Bombyx mori. We found that Ubx RNAi caused leg identity in A1 segment, abd‐A RNAi caused severe defect of abdominal prolegs and Abd‐B RNAi allowed proleg identity in more posterior abdominal segments. These results confirm that Lepidoptera hox genes Ubx and Abd‐B have evolved the repressing function to ventral appendage development, which is similar to those of Drosophila. However, Lepidoptera abd‐A might have been modified distinctively during evolution, and has important roles in directing the development of prolegs. © 2010 Wiley Periodicals, Inc.
The importance of exportin and Ran for nucleocytoplasmic shuttling of the ecdysteroid receptor
Authors: Betanska Katarzyna , Hönl Celine , Spindler‐Barth Margarethe , Spindler Klaus‐Dieter
Published: December 2010

Nuclear localization of the ecdysteroid receptor (EcR) is increased in HeLa cells if exportin‐1 (CRM1), a predominant carrier for export of proteins and RNA from the nucleus into the cytoplasm, is knocked down by siRNA against exportin. However, knockdown of the small G protein Ran, which is essential for nuclear transport, leads to an arrest of EcR in the cytoplasm, but does not prevent efficient nuclear import of the most important heterodimerization partner of EcR, ultraspiracle (Usp). Like in vertebrate cells, EcR is also distributed heterogeneously in Drosophila melanogaster S2 cells but shifted exclusively to the nucleus, if Usp is present. © 2010; Wiley Periodicals, Inc.
Cloning and expression pattern of 3‐dehydroecdysone 3β‐reductase (3DE 3β‐reductase) from the silkworm, Bombyx mori L.
Authors: Yang Hua‐jun , Liu Xin‐ju , Zhou Fang , Hu Jia‐biao , Bhaskar Roy , Li Xing‐hua , Sun Chun‐guang , Malik Firdose Ahmad , Niu Yan‐shan , Miao Yun‐gen
Published: December 2010

Molting in insects is regulated by molting hormones (ecdysteroids), which are also crucial to insect growth, development, reproduction, etc. Ecdysone was inactivated to 3‐dehydroecdysone (3DE) under ecdysone oxidase (EO), and followed by NAD(P)H‐dependent irreversible reduction to 3‐epiecdysteroid under 3DE 3a‐reductase. On the other hand, 3‐dehydroecdysone undergoes reversible reduction to ecdysone by 3DE 3β‐reductase in the hemolymph. In this article, we cloned and characterized 3‐dehydroecdysone 3β‐reductase (3DE 3β‐reductase) in the different tissues and the developing stage from the silkworm, Bombyx mori L. The B. mori 3DE 3β‐reductase cDNA contains an ORF 972 bp and the deduced protein sequence containing 323 amino acid residues. Analysis showed that the deduced 3DE 3β‐reductase belongs to the aldo‐keto reductase (AKR) superfamily, which has the NAD(P)‐binding domain, indicating that the function of 3DE 3β‐reductase depends on the existence of NAD(P)H. Using Escherichia coli, a high level expression of a fusion polypeptide band of approx. 40 kDa was observed. The high transcription of 3DE 3β‐reductase was mainly observed in the genitalia and fatty bodies in the third day of the fifth‐instar larvae, followed next in the head, epidermis, and hemocytes. The expression of 3DE 3β‐reductase in the early of every instar was lower than that in the late of instar. When the titer of 3DE is low, higher expression of 3DE 3β‐reductase is necessary to maintain the ecdysone titer in body through converting 3DE to ecdysone, while the 3DE titer is high, the expression of 3DE 3β‐reductase showed feedback inhibition. © 2010 Wiley Periodicals, Inc.
Oscillations in Homogeneous Systems
Authors: Noyes Richard M.
Published: December 2010

This manuscript reviews the present understanding of homogeneous chemical oscillators except for reactions occurring in gas phase or during enzyme catalysis. The best understood systems are driven by bromate oxidation of organic compounds, and many unusual temporal and spatial phenomena are explicable by a fairly simple mechanism. Progress is being made toward understanding oscillators based on iodate and hydrogen peroxide reactions. Nucleation phenomena are strongly implicated in gas evolution oscillators such as the dehydration of formic acid and the decomposition of ammonium nitrite. No oscillators based on sulfur chemistry are yet understood. Photochemically driven oscillators offer a rich potential that has not yet been exploited. Several condensed phase systems exhibit interesting spatial periodicities that involve coupling of diffusion with other processes. Possible mechanisms of oscillators are subject to kinetic, thermodynamic, and chemical constraints which are discussed briefly.
Thermokinetic Oscillations in Gaseous Systems
Authors: Gray Peter
Published: December 2010

This plenary lecture is a response to the Organizing Committee's request for a survey (i) of some of our own research in the field of oscillatory oxidation processes and (ii) of thermokinetic oscillations in a wider context. I shall accordingly deal with those systems in which the oscillatory behaviour springs from true reaction kinetic flexibility [1, 2] plus thermal feedback, rather than with those thermochemical oscillations [3] that really owe their existence wholly to sustained flow. Accordingly, the principal experimental themes to be pursued are (i) the oscillations found in the oxidation of hydrocarbons and related organic species, including the famous oscillatory cool flames, and (ii) the oscillatory oxidation of “wet” carbon monoxide. Both these reactions show oscillatory behaviour in closed vessels [1], so they are not simply artefacts of flowing conditions, but I shall here dwell on newer results that we have found in open systems. That will prompt some observations on the relationships between thermodynamically closed and open systems, and later raise some general questions about definitions or at least about more careful use of common terms (and a plea to do away with jargon).
Unstable and Oscillatory Behaviour in Heterogeneous Catalysis
Authors: Wicke E. , Kummann P. , Keil W. , Schiefler J.
Published: December 2010

With two examples, the oxidation of H2 and CO on Pt carrier catalysts, it is shown that special states of chemisorption and kinetics of surface processes can create periodicity and bistable behaviour of catalytic reactions. The (nonisothermal) oscillations of the H2 oxidation can be traced back to the superposition of a slow oxidation‐reduction process under participation of an active and an inactive (blocking) chemisorption species of oxygen, in agreement with TDS measurements. By means of a stability analysis, based on the linearized balance equations, the main features of the oscillatory behaviour can be explained. — With the CO oxidation oscillations under isothermal conditions have been studied that appear as precursors to a quenching of the reaction. A periodic change of the CO coverage (blocking) of the catalyst surface was demonstrated. For the formation of the CO coverage via CO clusters on the surface, in the sense of dissipative structures, a mechanism with co‐operation of the chemisorption process and the LH‐reaction is shown up. The periodic reactivation of the surface is attributed to the increase of desorption probability (decrease of desorption energy) with increasing packing density of the CO. A quantitative treatment, however, is not yet possible at present, because relationships for the kinetics of non‐random distributions on surface sites are missing.
Feedback Kinetics in Physicochemical Oscillators
Authors: Franck U. F.
Published: December 2010

Analogously to feedback mechanisms in electrical networks kinetical self‐influence of chemical reactions and physicochemical transportation processes may lead under certain conditions to oscillations, bistability, triggerability, reaction propagation and other temporal coupling phenomena. It is shown that all of these phenomena including dissipative structures can be interpreted and classified kinetically on the basis of positive, negative and antagonistic feedback.
Contribution to the Chemistry of the Belousov‐Zhabotinskii (BZ) Type Reactions
Authors: Noszticzius Zoltán , Bódiss János
Published: December 2010

Four new experimental observations are discussed which are difficult to interpret if we regard the bromide ion as a control intermediate of the BZ reaction. To explain the experimental facts two new hypothetical models: the bromine controlled (BC) model of the heterogeneous oscillations (substrate oxalic acid) and the Lotka‐Volterra (LV) model of the homogeneous oscillations with mixed substrate (oxalic acid‐aceton) are presented. Some variations of the more realistic LV model are mentioned.
Über die kinetischen Instabilitäten bei der CO‐Oxidation an Platin‐Katalysatoren
Authors: Keil W. , Wicke E.
Published: December 2010

Bei der CO‐Oxidation an Pt‐Katalysatoren werden unter isothermen Bedingungen sprunghaftes „Zünden”︁ und „Löschen”︁ der Reaktion sowie Oszillationen des Umsatzes beobachtet. Diese kinetischen Instabilitäten werden an einem Pt‐Trägerkontakt in einer Strömungsapparatur unter Normaldruck zwischen 100 und 300°C untersucht. Sie treten bei mittleren CO‐Gehalten von einigen Zehntel % bis einigen % CO in Luft auf. Für kleinere und höhere CO‐Gehalte kann die Kinetik der Reaktion durch einen einheitlichen Langmuir‐Hinshelwood‐Ansatz beschrieben werden, der die unterschiedlichen Chemisorptionszentren für CO und O2 auf der Pt‐Oberfläche berücksichtigt. Im mittleren Bereich wird mit einer speziell entwickelten Versuchstechnik eine reversible CO‐Blockierung der Pt‐Oberfläche als Ursache des instabilen Verhaltens der Reaktion festgestellt.
Folate pathway and nonsyndromic cleft lip and palate
Authors: Blanton Susan H. , Henry Robin R. , Yuan Quiping , Mulliken John B. , Stal Samuel , Finnell Richard H. , Hecht Jacqueline T.
Published: December 2010

BACKGROUND

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common complex birth defect. Periconceptional supplementation with folic acid, a key component in DNA synthesis and cell division, has reduced the birth prevalence of neural tube defects and may similarly reduce the birth prevalence of other complex birth defects including NSCLP. Past studies investigating the role of two common methylenetetrahydrofolate reductase (MTHFR) single‐nucleotide polymorphisms (SNPs), C677T (rs1801133) and A1298C (rs1801131), in NSCLP have produced conflicting results. Most studies of folate pathway genes have been limited in scope, as few genes/SNPs have been interrogated. Here, we asked whether variations in a more comprehensive group of folate pathway genes were associated with NSCLP, and were there detectable interactions between these genes and environmental exposures? METHODS: Fourteen folate metabolism‐related genes were interrogated using 89 SNPs in multiplex and simplex non‐Hispanic white and Hispanic NSCLP families. RESULTS: Evidence for a risk association between NSCLP and SNPs in NOS3 and TYMS was detected in the non‐Hispanic white group, whereas associations with MTR, BHMT2, MTHFS, and SLC19A1 were detected in the Hispanic group. Evidence for over‐transmission of haplotypes and gene interactions in the methionine arm was detected.

CONCLUSIONS

These results suggest that perturbations of the genes in the folate pathway may contribute to NSCLP. There was evidence for an interaction between several SNPs and maternal smoking, and for one SNP with gender of the offspring. These results provide support for other studies that suggest that high maternal homocysteine levels may contribute to NSCLP and should be further investigated. Birth Defects Research (Part A), 2011. © 2010 Wiley‐Liss, Inc.
Überblick über Regelungen zu Beton mit rezyklierter Gesteinskörnung
Authors: Hoffmann Cathleen , Jacobs Frank
Published: December 2010

Unter dem Aspekt der Nachhaltigkeit gewinnt die Verwendung rezyklierter Gesteinskörnung in der Betonindustrie zunehmend an Bedeutung, weshalb sowohl national als auch international Merkblätter und Normen geschaffen werden. Nachfolgend wird ein Überblick über diese Regelungen gegeben und Übereinstimmungen, Widersprüche und Wissenslücken aufgezeigt. Es wird vor allem auf europäische Länder eingegangen, da diese mehrheitlich die europäischen Normen (CEN) verwenden.
Feuchtesensoren in der Bauwerksüberwachung
Authors: Sodeikat Christian
Published: December 2010

Die Bestimmung des Wassergehalts und insbesondere der orts‐ und zeitabhängigen Feuchteverteilung in Baustoffen hat in der Forschung, Baustoffentwicklung, Bauwerksdiagnose und Bauwerksüberwachung einen besonderen Stellenwert. Bei der Untersuchung von Schadensursachen muss an Bauwerken in der Regel die Baustofffeuchte mit bewertet werden, da sowohl wesentliche Baustoffeigenschaften als auch die Dauerhaftigkeit von Bauwerken in entscheidendem Maße von deren Wassergehalt abhängig sind. In jüngster Zeit werden Feuchtesensoren eingesetzt, um die Funktionsfähigkeit und Dauerhaftigkeit von Instandsetzungs‐ bzw. Schutzmaßnahmen zu kontrollieren. Dies soll es dem Bauherrn ermöglichen, rechtzeitig Maßnahmen einleiten zu können, bevor Schäden infolge von Wasser‐ bzw. Chloridzutritt auftreten können.

Condition Assessment with Moisture Sensors

The determination of the water content in construction materials and in particular with regard to its depth and time dependent distribution is of high interest in the area of research, material development and condition assessment of structures. The assessment of the reason of damages mostly require to regard the moisture content of structures, because the moisture content basically affects material properties and the durability of structures. Recently moisture sensors have been used to control the functionality and durability of repair and protection measures. This enables the owner to carry out accurately timed measures to prevent damages due to the ingress of water and chlorides.
Verifizierung moderner zerstörungsfreier Prüfverfahren an einem Abbruchbauwerk
Authors: Taffe Alexander , Hillemeier Bernd , Walther Andrei
Published: December 2010

Die Entwicklung zerstörungsfreier Prüfverfahren im Bauwesen (ZfPBau‐Verfahren) hat in den letzten Jahren zu einer rasanten Leistungssteigerung geführt. Etliche Verfahren haben das Potenzial, in der Zukunft vom “Stand der Wissenschaft” zum “Stand der Technik” zu werden. Damit dies geschieht, muss möglichen Kunden vermittelt werden, welche Prüfaufgabe mit welchem Verfahren bearbeitet werden kann und wie zuverlässig die Ergebnisse sind. Um die Leistungsfähigkeit von ZfPBau‐Verfahren nachzuweisen, ist eine genaue Kenntnis des wirklichen Bestands und der tatsächlichen Schäden erforderlich, um diese mit den Messergebnissen zu vergleichen und deren Güte zu bewerten. Mit dem Abriss der Spandauer‐ Damm‐Brücke in Berlin ergab sich die Gelegenheit, zunächst eine großflächige Zustandsermittlung der Fahrbahnplatte bezüglich des Grads vorhandener Korrosionsschäden und des Verpresszustands von Spanngliedern vorzunehmen. Durch den vorgefundenen Zustand der Quervorspannung mit nachweislich vorhandenen Brüchen der Spanndrähte konnte an diesem Abrissbauwerk die Leistungsfähigkeit des Remanenzmagnetismusverfahrens zur Ortung von Spanndrahtbrüchen erstmals großflächig nachgewiesen werden, wobei auch der Vergleich der Untersuchungen mit und ohne Fahrbahnbelag durchgeführt wurde. Da der Anteil an vorhandenen Verpressfehlern nach großflächiger Auswertung sich als sehr gering herausstellte und an den ausgelösten Brückenteilen keine Verpressfehler vorhanden waren, wird in diesem Beitrag die Leistungsfähigkeit der Kombination von Radar und Ultraschall mit bildgebender Darstellung gezeigt. Damit wird es künftig möglich sein, Informationen zur Rekonstruktion nicht vorhandener Bestandspläne zu gewinnen.
Nachrichten: Beton‐ und Stahlbetonbau 12/2010
Authors: Stroetmann Richard , Hanek Dieter
Published: December 2010

60 Jahre Krebs und Kiefer

BDB‐Studentenförderpreis 2011

6. Hans Lorenz Symposium für Baugrunddynamik und Spezialtiefbau

VBI: HOAI‐Novelle muss deutlich weiter reichen

Neuauflage der VBI‐VOF‐Broschüre
Photonic immobilization of bsa for nanobiomedical applications: creation of high density microarrays and superparamagnetic bioconjugates
Authors: Parracino Antonietta , Gajula Gnana Prakash , di Gennaro Ane Kold , Correia Manuel , Neves‐Petersen Maria Teresa , Rafaelsen Jens , Petersen Steffen B.
Published: December 2010

Light assisted molecular immobilization has been used for the first time to engineer covalent bioconjugates of superparamagnetic nanoparticles and proteins. The technology involves disulfide bridge disruption upon UV excitation of nearby aromatic residues. The close spatial proximity of aromatic residues and disulfide bridges is a conserved structural feature in proteins. The created thiol groups bind thiol reactive surfaces leading to oriented covalent protein immobilization. We have immobilized a model carrier protein, bovine serum albumin, onto Fe3O4@Au core–shell nanoparticles as well as arrayed it onto optically flat thiol reactive surfaces. This new immobilization technology allows for ultra high dense packing of different bio‐molecules on a surface, allowing the creation of multi‐potent functionalized active new biosensor materials, biomarkers identification and the development of nanoparticles based novel drug delivery system. Bioeng. 2011; 108:999–1010. © 2010 Wiley Periodicals, Inc.