bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of estragole and other odorants on the flavour of anise and tarragon
Authors: Zeller Annette , Rychlik Michael
Published: December 2006

Since estragole has been described as potent carcinogen and did not show any flavour impact on the odour of fennel, the flavour of anise and tarragon was examined by combinations of instrumental and sensory analyses. In anise fruits, trans‐anethole, 2‐isopropyl‐3‐methoxypyrazine, and anisaldehyde showed high flavour dilution (FD) factors, followed by those of eugenol, cis‐anethole, estragole and linalool. Quantitation of the odorants showing higher FD factors in anise tea, and calculation of odour activity values (OAVs) by dividing the concentrations of the respective compound by its recognition threshold in water revealed the highest OAV for trans‐anethole, followed by those of anisaldehyde and estragole. Still, an aroma impact of estragole next to trans‐anethole could be neglected, due to former sensory studies of aqueous models of fennel tea. For tarragon, AEDA revealed the highest FD factors for eugenol, 7‐methoxycoumarin, β‐ionone, 2‐isopropyl‐3‐methoxypyrazine, estragole and linalool. Of these, estragole and 7‐methoxycoumarine were most abundant in tarragon leaves, showing contents of 2900 and 220 mg/kg, respectively. To calculate OAVs, the contents of potent odorants were divided by their odour threshold in starch or cellulose, as these were the main constituents of the leaves. In this way, β‐ionone and eugenol showed the highest OAVs of 5862 and 2653, repectively, followed by estragole (OAV = 460), cis‐1,5‐octadiene‐3‐one (OAV = 140), vanilline (OAV = 139) and 2‐isopropyl‐3‐methoxypyrazine (OAV = 130). Therefore, it was concluded that β‐ionone and eugenol made the greatest contribution to the overall flavour of tarragon, whereas estragole and the other odorants were of minor importance. Copyright © 2006 John Wiley & Sons, Ltd.
Volatile composition and olfactory profile of pennyroyal (Mentha pulegium L.) plants
Authors: Díaz‐Maroto M. Consuelo , Castillo Noelia , Castro‐Vázquez Lucía , Ángel González‐Viñas Miguel , Pérez‐Coello M. Soledad
Published: December 2006

The composition of volatile oil extracts of pennyroyal (Mentha pulegium L.) plants was investigated by gas chromatography–mass spectrometry. Those volatiles responsible for the characteristic minty and pungent aroma of this plant were determined by gas chromatography–olfactometry. Volatile oil extracts were found to be rich in oxygenated monoterpenes, mainly pulegone and piperitone oxide, followed by isopulegol, piperitone and piperitenone. Major monoterpenes hydrocarbons were limonene and α‐pinene, while sesquiterpenoids were detected in low levels. With respect to the aroma characteristics, pulegone was found to have an intense mint, balsamic and pungent aroma. Other compounds with minty notes were isopulegone, piperitol and 1,8‐cineole. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of the interactions among macronutrients, plant age and photoperiod in the composition of Hyptis suaveolens (L.) Poit essential oil from Alfenas (MG), Brazil
Authors: Martins Felipe T. , Santos Marcelo H. , Polo Marcelo , Barbosa Luiz C. A.
Published: December 2006

This study was performed to verify the influence of photoperiod, plant age and nitrogen, phosphorus and potassium availability in the essential oil composition of Hyptis suaveolens (L.) Poit from Alfenas (MG), Brazil. The plants were grown in a greenhouse and six treatments were used. These treatments were harvested at two different periods (60 and 135 day‐old plants). The essential oil composition was determined by GC–MS analysis using a DB5 bonded phase column. The terpenes spathulenol (8.43–24.70%), globulol (6.89–14.55%), dehydroabietol (3.84–11.80%), α‐cadinol (4.25–8.05%) and β‐phellandrene (2.91–4.40%) were the major constituents found in the essential oil. Spathulenol amounts changed according to nitrogen and phosphorus availability, related to plant age. Oxygenated sesquiterpenes (33.09–49.55%) represented the main group of constituents in most of the treatments, while the amounts of oxygenated diterpenes (5.68–18.07%) increased in 135 day‐old plants. In addition, a pattern of terpenoid oxidation related to the plant age was suggested. The major changes in the essential oil composition were found in 60 day‐old plants grown under nitrogen and phosphorus deficiencies and extended photoperiod. In conclusion, the interaction among the tested macronutrients, photoperiod and plant age may be related to the essential oil composition of H. suaveolens from Alfenas, Brazil. Copyright © 2006 John Wiley & Sons, Ltd.
Volatile constituents of natural Boswellia serrata oleo‐gum‐resin and commercial samples
Authors: Singh Bikram , Kumar Ripudaman , Bhandari S. , Pathania S. , Lal Brij
Published: December 2006

The essential oils of Boswellia serrata Roxb. ex Colebr. oleo‐gum‐resin collected from four different locations (samples A–D) were isolated by hydrodistillation and analysed by means of GC and GC–MS. Thirty‐five components were identified, comprising 82%, 91%, 77% and 82% of samples A, B, C and D, respectively. α‐Thujene was one of the major constituents in all samples, whereas α‐pinene was recorded in only one sample. All the oils were dominated by monoterpene hydrocarbons. Copyright © 2006 John Wiley & Sons, Ltd.
Volatiles of Anaxagorea dolichocarpa Spreng. & Sandw. and Annona densicoma Mart. growing Wild in the state of Pará, Brazil
Authors: Andrade Eloisa Helena A. , Oliveira Jorge , das Graças B. Zoghbi Maria
Published: December 2006

The volatiles of Anaxagorea dolichocarpa and Annona densicoma were obtained by hydrodistillation and analysed by GC and GC–MS. The main components of the leaf and stem oils of A. dolichocarpa were spathulenol (26.2%, 21.2%), α‐pinene (16.8%, 23.4%), and β‐pinene (12.3%, 17.0%), respectively. The major components identified in the leaf oil of A. densicoma were germacrene D (28.8%), bicyclogermacrene (26.8%), and β‐caryophyllene (14.4%). Copyright © 2006 John Wiley & Sons, Ltd.
Cranial musculature in the larva of the caecilian, Ichthyophis kohtaoensis (Lissamphibia: Gymnophiona)
Authors: Kleinteich Thomas , Haas Alexander
Published: December 2006

Within the Gymnophiona (caecilians) oviparous species with biphasic life‐cycles possess a free living semi‐aquatic larval stage that feeds in aquatic habitats. The larvae pass through a metamorphosis to a purely terrestrial adult stage. It is likely that the cranial morphology of caecilian larvae has specializations for aquatic feeding. However, little is known about the cranial morphology, and the cranial musculature is especially neglected in the literature. This study provides a detailed description of the jaw and hyobranchial musculature in larval stages of a caecilian. We studied late embryonic and early larval specimens of Ichthyophis kohtaoensis. Furthermore, we compared and homologized the cranial muscles found in larval I. kohtaoensis with the muscles described for adult caecilians. Most cranial muscles of larval I. kohtaoensis are also present in the adult, except for the m. levator mandibulae externus and the m. subarcualis obliquus II. Our results were compared with the data available for larval frogs and salamanders in order to hypothesize the cranial musculature in the larva of the most recent common ancestor of the Lissamphibia. Larval caecilians, frog tadpoles, and salamander larvae share many characters in their cranial musculature, which, consequently, can be assigned to the lissamphibian ground pattern. However, the m. pterygoideus and the m. levator quadrati are unique to the Gymnophiona. J. Morphol., 2007. © 2006 Wiley‐Liss, Inc.
Characterization of 2‐methylglyceric acid oligomers in secondary organic aerosol formed from the photooxidation of isoprene using trimethylsilylation and gas chromatography/ion trap mass spectrometry
Authors: Szmigielski Rafal , Surratt Jason D. , Vermeylen Reinhilde , Szmigielska Katarzyna , Kroll Jesse H. , Ng Nga L. , Murphy Shane M. , Sorooshian Armin , Seinfeld John H. , Claeys Magda
Published: December 2006

In the present work, we have characterized in detail the chemical structures of secondary organic aerosol (SOA) components that were generated in a smog chamber and result from the photooxidation of isoprene under high‐NOx conditions typical for a polluted atmosphere. Isoprene high‐NOx SOA contains 2‐methylglyceric acid (2‐MG) and oligoester derivatives thereof. Trimethylsilylation, in combination with capillary gas chromatography (GC)/ion trap mass spectrometry (MS) and detailed interpretation of the MS data, allowed structural characterization the polar oxygenated compounds present in isoprene SOA up to 2‐MG trimers. GC separation was achieved between 2‐MG linear and branched dimers or trimers, as well as between the 2‐MG linear dimer and isomeric mono‐acetate derivatives thereof. The electron ionization (EI) spectra of the trimethylsilyl derivatives contain a wealth of structural information, including information about the molecular weight (MW), oligoester linkages, terminal carboxylic and hydroxymethyl groups, and esterification sites. Only part of this information can be achieved with a soft ionization technique such as electrospray (ESI) in combination with collision‐induced dissociation (CID). The methane chemical ionization (CI) data were used to obtain supporting MW information. Interesting EI spectral differences were observed between the trimethylsilyl derivatives of 2‐MG linear and branched dimers or trimers and between 2‐MG linear dimer mono‐acetate isomers. Copyright © 2006 John Wiley & Sons, Ltd.
Release of nutrients dissolved organic carbon during decomposition of Chamaecyparis obtusa var. formosana leaves in a mountain forest in Taiwan
Authors: Rees Rainer , Chang Shih‐Chieh , Wang Chiao‐Ping , Matzner Egbert
Published: December 2006

Forest ecosystems in Taiwan are periodically influenced by typhoons that cause large amounts of litter input to the soil. The potential rapid decomposition of such litter under the warm and moist climatic conditions in Taiwan may lead to nutrient losses via seepage. The goal of this study was to investigate the dynamics of C, N, K, Ca, Mg, and dissolved organic carbon (DOC) during decomposition of Chamaecyparis obtusa var. formosana leaves in a field study at the Yuanyang Lake site in N Taiwan. We simulated the effect of a typhoon by adding about three times the annual aboveground litterfall (totally 13,900 kg ha–1) as fresh leaves. Litterbags were taken at 7 dates over 16 months, followed by detection of mass loss and element composition in the remaining litter. Aqueous extracts of the remaining litter were analyzed for DOC and major elements. The properties of DOC were characterized by fluorescence spectra and by its stability against microbial decomposition.

The litter mass loss was 35% after 16 months. The losses of Ca after 16 months from the litter bags were about equivalent to mass loss (39%), while those of K and Mg reached 86% and 60% of the initial amount, respectively. From the 13,900 kg ha–1 of litter applied in total, 59 kg K ha–1 and 12 kg Mg ha–1 were released in the 16 months decomposition period, most of it in the first 4 months. The total release of Ca amounted to 69 kg ha–1 but was more evenly distributed throughout the 16 months of observation. The absolute amount of N in the decomposing litter increased by 37% while the C : N decreased from 69 to 34. Extrapolated to the manipulation treatment, this resulted in a N gain of 36 kg N ha–1 within 16 months.

The leaching of K and DOC in laboratory extractions followed an asymptotic function with highest leaching from the initial litter and subsequent decrease with time of decomposition. On the contrary, the leaching of Ca and Mg reached a maximum after 2–4 months of incubation. About 2% of the C was extractable with water from the initially incubated leaves. The bioavailability of the extracted DOC decreased with litter age.

Our results indicate that the decomposition of large amounts of litter induces a high risk of K and Mg losses with seepage, but the risk for N losses is low. The sources of N accumulation in decomposing litter at this site require further studies. In the initial phase of litter decomposition, the release of DOC seems to be an important contribution to mass loss.
Rice yield nutrient uptake as affected by cyanobacteria soil amendments—a pot experiment
Authors: El Sharkawi Haytham , Yamamoto Sadahiro , Honna Toshimasa
Published: December 2006

Rice production and cyanobacterial N in acid soil can be improved by liming. There is evidence that the organic amendments can increase the soil pH. The aim of this study was to find appropriate combination of soil amendments and cyanobacteria capable for enhancing nutrient uptake and improving rice yield in acidic paddy soil. Three soil amendments (rice straw, sewage‐sludge composts, NPK) with and without inoculation of cyanobacteria were studied for rice plants (Oryza sativa L.) in a pot experiment. The sludge compost had significantly reduced soil acidity from 5.44 to 6.67. The plant N and K uptake increased significantly with sludge and cyanobacteria application. The yield components increased significantly with sludge, but decreased thereafter, an exception was the number of panicles, with straw compost. These characters were also significantly affected by inoculation with cyanobacteria except 100‐grain weight, filled‐grain percentage, and harvest index. The combination of sludge compost and cyanobacteria improved the yield components and consequently grain yield (138 g pot–1) compared with sludge treatment only (132 g pot–1). The amount of cyanobacterial N absorbed (N‐difference method) by rice plant under sludge compost was higher than that of soils amended with either rice straw or NPK treatments. Therefore, the addition of sewage sludge to acid paddy soil not only amended the soil properties but also activated the cyanobacteria and consequently improved rice plant nutrition and grain yield.
Assessment of the soil phosphorus–mobilization potential by microbial reduction using the Fe(III)‐reduction test
Authors: Thiele‐Bruhn Sören
Published: December 2006

The mobility of soil P is greatly influenced by the redox potential (Eh), which depends on the reducing activity of soil microorganisms. Standard extraction methods for the determination of the mobile soil P disregard the P mobilization caused by the influence of microorganisms on Eh, while P test methods that include soil microbial activities are lacking. Thus, the Fe(III)‐reduction test was investigated for its suitability to determine the P fraction that is mobilized in soil under reducing conditions (PRed). In this test, the soil‐microbial reducing activity is measured from the microbial Fe(III) reduction combining a bioassay with 7 d incubation and a chemical extraction using 1M KCl. After the incubation, Eh in 26 different soil samples ranged from –282 to –123 mV. The concentration of PRed in the soil samples ranged from concentrations below the limit of detection to 84.9 mg kg–1 and was on average of all soil samples by a factor of 2.4 to 18 smaller than the P fractions determined by standard soil P–extraction methods. As standard agronomic and environmental P extractants, respectively, water (PH2O), dithionite citrate bicarbonate (PDith), ammonium oxalate (POx), ammonium lactate (PAL), double lactate (PDL), and sodium bicarbonate (POlsen) were selected. The PRed fraction was not correlated with PAL, PDL, Polsen, and the degree of P saturation, but with PH2O (r = 0.43*), PDith (r = 0.60***), and POx (r = 0.61***). Furthermore, PRed depended on the concentration of amorphous Fe oxides (FeOx, r = 0.53**) and was closely correlated with the concentration of microbially reduced Fe (FeRed, r = 0.94***). This indicated the influence of the Fe(III)‐reducing activity of soil microorganisms on P mobilization. In subsoils, low in Fe(III)‐reducing activity, no P was released by the Fe(III)‐reduction test, which was in contrast to the results from the other chemical extraction methods. Additional alterations of the microbial activity by inhibiting and activating amendments, respectively, clearly affected the microbial Fe(III)‐reducing activity and the associated release of PRed. Thus, PRed, determined by the Fe(III)‐reduction test, might be termed as the fraction that is potentially released from soil by microbial reduction.
Heavy soil loading its consequence for soil structure, strength, deformation of arable soils
Authors: Peth Stephan , Horn Rainer , Fazekas Orsolya , Richards Brian G.
Published: December 2006

The alteration of mechanical soil properties by a single stress application exceeding all previously applied stresses is analyzed for a conventionally tilled and a conservational managed (since 1992) Stagnic Luvisol. Despite the more pronounced compactness of the plough layer under conventional management, it turned out to be less rigid compared to the “relictic” plough layer under conservation management. We assume that wheeling with a sugar beet harvester (rear wheel 140 kPa, front wheel 110 kPa, total mass 37 Mg) resulted in a break up of the plough pan. This was most obvious in the conventionally tilled soil whereas under conservation tillage, the plough pan seemed to resist the induced forces. Our results suggest that a break up of the compact plough layer and the subsequent re‐arrangement of newly formed fragments results in a smaller mechanical stability of the deformed soil. Soil structural changes within the plough pan are also indicated by the alteration of the anisotropy of cohesion and precompression stress, respectively. Altered mechanical properties induced by heavy soil loading affects the soil response to subsequent loading events, which could be shown by finite‐element simulations of stress‐strain properties. The simulations showed that a decrease in soil stiffness reduces the stress attenuation within the plough pan causing compressive and shear stresses to be transmitted into deeper soil levels, while at the same time shear strain increased.
Universality of a surface tension—contact‐angle relation for hydrophobic soils of different texture
Authors: Bachmann Jörg , Arye Gilboa , Deurer Markus , Woche Susanne K. , Horton Robert , Hartge Karl‐Heinz , Chen Yona
Published: December 2006

Wettability of soil affects a wide variety of processes in soils like infiltration, percolation, preferential flow, and surface runoff. Even though efforts have been made to determine contact angles and surface tension or energy of smooth surfaces, the determination on granular materials like soil particles remains unsolved. One objective of this study was to test the consistency of contact angles (CA) measured with the newly modified and easy‐to‐apply Wilhelmy plate method by using solid particles and liquids with defined variations of surface tension. A second objective was to derive basic physical surface properties for the irregularly shaped and chemically heterogeneous soil particles. Advancing contact angles were determined by using model soils varying in texture from clay to coarse sand to check the impact of grain size on the CA measurements. Varying the solid‐surface tension with dichlorodimethlylsilane treatments provided for pure‐water wetting stages ranging from wettable to extremely hydrophobic. The surface tensions of the liquids were varied from 72 mN m–1 to 25 mN m–1 by using water or water‐ethanol mixtures. The surface tensions of the model soils were determined with the zero degree–contact angle method following Zisman's critical–surface tension concept. Results show that the measured CA varied continuously with the variations of the surface tension of the liquid and the solid phase, respectively. A general interpretation of the results is possible by using the concept of the Equation of State Approach.
Fabrication and characterization of SERS‐active silver clusters on glassy carbon
Authors: Wang Yuling , Chen Hongjun , Dong Shaojun , Wang Erkang
Published: December 2006

In this article, a novel technique for the fabrication of surface enhanced Raman scattering (SERS) active silver clusters on glassy carbon (GC) has been proposed. It was found that silver clusters could be formed on a layer of positively charged poly(diallyldimethylammonium) (PDDA) anchored to a carbon surface by 4‐aminobenzoic acid when a drop containing silver nanoparticles was deposited on it. The characteristics of the obtained silver clusters have been investigated by atomic force microscopy (AFM), SERS and an SERS‐based Raman mapping technique in the form of line scanning. The AFM image shows that the silver clusters consist of several silver nanoparticles and the size of the clusters is in the range 80–100 nm. The SERS spectra of different concentrations of rhodamine 6G (R6G) on the silver clusters were obtained and compared with those from a silver colloid. The apparent enhancement factor (AEF) was estimated to be as large as 3.1 × 104 relative to silver colloid, which might have resulted from the presence of ‘hot‐spots’ at the silver clusters, providing a highly localized electromagnetic field for the large enhancement of the SERS spectra of R6G. The minimum electromagnetic enhancement factor (EEF) is estimated to be 5.4 × 107 by comparison with the SERS spectra of R6G on the silver clusters and on the bare GC surface. SERS‐based Raman mapping technique in the form of line scanning further illustrates the good SERS activity and reproducibility on the silver clusters. Finally, 4‐mercaptopyridine (4‐Mpy) was chosen as an analyte and the lowest detected concentration was investigated by the SERS‐active silver clusters. A concentration of 1.6 × 10−10 M 4‐Mpy could be detected with the SERS‐active silver clusters, showing the great potential of the technique in practical applications of microanalysis with high sensitivity. Copyright © 2006 John Wiley & Sons, Ltd.
Placing customer service strategy in the context of a vertical marketing system
Authors: Lee Yang‐Im , Trim Peter R.J.
Published: December 2006

International retailing is undergoing rapid change and because of this senior managers need to understand how to manage the change process and develop working relationships with their counterparts in partner organizations.

By embracing organizational learning it is possible for a retail organization to formulate a vertically integrated strategy that provides superior customer value and results in the formation of trust‐based relationships. These should be underpinned by mutuality and possess a strategic focus.

Copyright © 2006 John Wiley & Sons, Ltd.
Unlocking synergies between business units: internal value creation at Royal Vopak
Authors: Ansari Shahzad , Schouten Martijn , Verwaal Ernst
Published: December 2006

This paper examines the process of creating and exploiting synergies between business units of a multi‐unit corporation and the creation of internal value by combining and exploiting knowledge.

It offers a framework to create and manage such synergies and undertakes an empirical test through in‐depth study across three business units of Royal Vopak, a Dutch‐based global multi‐unit corporation. Finally, it offers lessons for corporate managers trying to create and manage cross‐unit synergies.

Copyright © 2006 John Wiley & Sons, Ltd.
A diagnostic framework for building HR capability in organizations
Authors: Hiltrop Jean M.
Published: December 2006

This paper examines some of the key factors that influence the impact of strategic HRM on organizational capability and performance. Particular attention is given to the factors that contribute towards the increasingly important capability of attracting and keeping talent in organizations and the practical implications of these factors for the way in which human talent is managed in knowledge‐intense firms.

The questions addressed here are: What are the key factors that increase organizational capability to get and keep the right types of people? How can these factors be managed in order to create and sustain competitive advantage? What are the implications for the HR strategy and effective people management?

Copyright © 2006 John Wiley & Sons, Ltd.
The effect of hard coated metals on the thermo‐oxidative stability of a branched perfluoropolyalkylether lubricant
Authors: Hellman Patrick T. , Zabinski Jeffery S. , Gschwender Lois , Snyder Carl E. , Korenyi‐Both Andras L.
Published: December 2006

M‐50 and carburized Pyrowear 675® (Carpenter Technology, Reading PA, USA) steel coupons deposited with commercially available physical vapour deposited TiN, TiCN, TiAlCN, TiCrCN/TiB4C multilayer, electroless Ni (E‐Ni) TiN and E‐Ni TiCN coatings were immersed in a branched perfluoropolyalkylether (PFPAE), Krytox AC® (E.I. du pont de Nemours and Company, Wilmington DE, USA), in an oxidative environment at temperatures ranging from 315 to 360 °C for a duration of 24 hours and compared with uncoated coupons. Coated and uncoated Pyrowear 675® coupons demonstrated superior corrosion resistance compared with coated and uncoated M‐50 respectively. The coatings most resistant to chemical attack in the PFPAE fluid were TiCN, E‐Ni TiN and E‐Ni TiCN. Copyright © 2006 John Wiley & Sons, Ltd.
Metallocene Catalysts for 1‐Butene Polymerization
Authors: Resconi Luigi , Camurati Isabella , Malizia Federica
Published: December 2006

Summary: Isotactic polybutenes of variable isotacticity and melting points of form I in the range 100–125 °C have been prepared with both C2‐ and C1‐symmetric zirconocenes. The C1‐symmetric zirconocenes bearing the bilateral symmetric 2,5‐dimethyl‐7H‐cyclopenta[1,2‐b:4,3‐b′]dithiophene ligand connected by a dimethylsilandiyl bridge to a substituted indenyl ligand produce iPB with higher molecular mass, up to 400 000 at polymerization temperature of 70 °C in liquid butene. The degree of isotacticity depends on the substitution pattern of the indenyl ligand. The correlations between microstructure and melting points of the crystalline forms I and II of iPB have been defined. Some relevant differences in catalyst selectivity between propylene and 1‐butene polymerizations have been identified.

Linear correlation of melting points of form I and form II in isotactic poly(1‐butene)s of different chain regularities.

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Linear correlation of melting points of form I and form II in isotactic poly(1‐butene)s of different chain regularities.
A Highly Efficient Polyurethane‐Type Polymeric Photoinitiator Containing In‐chain Benzophenone and Coinitiator Amine for Photopolymerization of PU Prepolymers
Authors: Wei Jun , Wang Hongyu , Jiang Xuesong , Yin Jie
Published: December 2006

Summary: A novel polyurethane‐type polymeric photoinitiator (PUIOA) was synthesized through polycondensation of a novel diamine AAPBP, TDI and MDEA. The BP and coinitiator amine structures were successfully introduced into the backbones of PUIOA. A polymeric photoinitiator without the coinitiator amine in the polymer chain (PUIO) was also synthesized for comparison. FT‐IR, 1H NMR and GPC analyses confirmed the structures of polymeric photoinitiators. The UV‐vis spectra of PUIOA and PUIO are similar to the parent AAPBP, and both exhibit high red‐shifted maximal absorption as compared with BP. ESR spectra indicate that PUIOA can generate free radicals most efficiently. Photopolymerization of the Polyurethane prepolymer, initiated by PUIOA, PUIO/MDEA, AAPBP/MDEA and BP/MDEA, was studied by photo‐DSC. The results show that PUIOA is the most efficient photoinitiator for PU prepolymer.

Synthesis routes for polymeric photoinitiators.

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Synthesis routes for polymeric photoinitiators.
Potentiometric Titrations of Maleic Acid Copolymers in Dilute Aqueous Solution: Experimental Results and Theoretical Interpretation
Authors: Delben Franco , Paoletti Sergio , Porasso Rodolfo D. , Benegas Julio C.
Published: December 2006

Summary: The paper reports a study on the flexibility of a family of 1:1 hydrolysed maleic anhydride (maleic acid, MA)–olefin copolymers in dilute aqueous solution. The copolymers were MA–ethene, MA–propene and MA–isobutene. The study was carried out in the absence and in the presence of monomonovalent salts and at different polymer concentrations. Experimental data showing the negative logarithm of the ‘apparent’ dissociation constant, pKa versus the degree of dissociation, α, experimental data were obtained from potentiometric titrations using NaOH, KOH or tetramethylammonium hydroxide as the base. The pKa data were fully described with calculated curves obtained using an extension of the counterion condensation theory of linear polyelectrolytes, in which a semiflexible model for the polymers was introduced. Under the present experimental condition, no relevant specificity of the monovalent counterions was apparently observed for the different copolymers. The calculated pKa versus α curves allowed the derivation of both the intrinsic dissociation constants of the first and the second dissociation steps for the different copolymers and the corresponding stiffness parameters built into the model. The agreement between the experimental and calculated data shows an appreciable success of the model. The results pointed to an increase of stiffness parallel to the increase of size of the olefin comonomer, in qualitative agreement with already published findings. Furthermore, for all copolymers the chain rigidity was larger in the α range of the first dissociation than in that of the second one. The former rigidity was attributed to the formation of intramolecular hydrogen bonds upon the first ionisation of the MA repeating units, followed by an increase of rotational freedom upon breaking of the H‐bond in the second dissociation step. Comparison of the rigidity parameters of the MA copolymers with the data obtained for other polyelectrolytes, both natural—poly(L‐glutamic acid) and pectic acid—and synthetic—poly(acrylic acid) and poly(methacrylic acid)—was also performed.

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The keto–enol tautomerization of ethyl butylryl acetate studied by LC‐NMR
Authors: Zhou Casey Chun , Hill David R.
Published: December 2006

The keto–enol tautomerism of ethyl butylryl acetate was studied in mixed solvents under a variety of experimental conditions. The direct measurement of ketonization of the enol tautomer was performed by using the hyphenated technique LC‐NMR. The keto and enol tautomers can be separated by using HPLC and their interconversion is a slow process on the NMR timescale. The ketonization reaction was found to be acid catalyzed and the solvent isotope effect, k/k, in an acetonitrile/water mixture, is 5.4. The ketonization rate constants were also measured at different compositions of binary solvents, such as CH3CN/D2O, CD3OD/D2O, and CH3CN/CD3OD. The rate constant and water percentage were found to have an exponential relationship. The reaction rate as a function of solvent polarity will be discussed in this paper. Copyright © 2006 John Wiley & Sons, Ltd.
A PGSE diffusion and electrophoretic NMR study of Cs+ and Na+ dynamics in aqueous crown ether systems
Authors: Price William S. , Hallberg Fredrik , Stilbs Peter
Published: December 2006

Multinuclear pulsed gradient spin‐echo (PGSE) NMR diffusion and linewidth measurements were used to probe binding and transport in aqueous Na+‐15‐crown‐5, Na+‐18‐crown‐6, Cs+‐15‐crown‐5 and Cs+‐18‐crown‐6 systems. Since direct PGSE observation of many alkali cations is precluded by either low inherent sensitivity or rapid relaxation (or both), the feasibility of proton‐detected electrophoretic NMR (ENMR) measurements to complement PGSE data was investigated. ENMR measurements were performed on aqueous Cs+‐, Li+‐, Na+‐, K+‐, and Rb+‐ 18‐crown‐6 systems. The data analysis is based on a two‐site binding model and its corresponding association constants. Cs+ was found to bind considerably more tightly to 18‐crown‐6 (K = 8 M−1) than to 15‐crown‐5 (K ∼ 2 M−1), whereas Na+ had almost equal affinity (K ∼ 4.5 M−1) for 15‐crown‐5 and 18‐crown‐6. The difficulties encountered in analysing the NMR parameters, methodological limitations and the implied need for more complicated binding models are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Peripheral nerve stimulation and monitoring during operative procedures
Authors: Crum Brian A. , Strommen Jeffrey A. , Stucky S. C.
Published: December 2006

Monitoring of peripheral nerve function is important during the surgical treatment of peripheral nerve and plexus lesions, allowing for rapid assessment of the integrity of the roots, plexus, and nerves. The results of this monitoring assist the surgeon in the overall approach to treatment of these lesions. There are, however, many technical challenges to providing this neurophysiological information in an accurate and rapid fashion. This study assesses the equipment and techniques involved in intraoperative peripheral nerve monitoring and describes its use in the more common clinical scenarios. Muscle Nerve, 2006
On determinantal representation for the generalized inverse A and its applications
Authors: Cai Jing , Chen Guoliang
Published: December 2006

In this paper, first we establish a determinantal representation for the group inverse Ag of a square matrix A. Based on this, a determinantal representation for the generalized inverse A is presented. As an application, we give a determinantal formula for the unique solution of the general restricted linear system: Ax=b(x ∈ T, b ∈ AT and dim(AT)=dim(T)), which reduces to the common Cramer rule if A is non‐singular. These results extend our earlier work. Copyright © 2006 John Wiley & Sons, Ltd.
Dynamic mechanical properties of filled styrene butadiene rubber compounds: comparison of tensile and shear data
Authors: Konečný P. , Černý M. , Voldánová J. , Maláč J. , Šimoník J.
Published: December 2006

Most rubber articles are prepared from filler‐elastomer compounds and dynamic mechanical data can give valuable insight into behavior of such systems. The aim of this study was to compare complex tensile modulus E* and complex shear modulus G* using seven types of vulcanized filled rubbers and two testing devices.

Carbon black and clay filled styrene butadiene rubber (SBR) compounds were tested. The E* value was measured using a dynamic mechanical analyzer (DMA DX04T from R.M.I.) and the G* value using a rubber process analyzer (RPA 2000 from Alpha Technologies) at 1 Hz, 30°C and at small deformation amplitudes common to both devices. For characterization of tested materials absolute values of complex modulus |E*| and |G*| were used together with values of loss factor tan δ.

The highest values of |E*|, |G*| and tan δ in tested carbon blacks were obtained for type N330. The highest values of |E*|, |G*| and tan δ in tested clay fillers were found for organoclay Cloisite 93A.

Maximum at the dependence tan δ/amplitude, obtained in a broader shear amplitude range, was found to be smaller for carbon black filled compounds than expected and maximum at this dependence for clay filled compounds was not observed.

The amplitude dependences of analogous dynamic mechanical characteristics from dynamic mechanical analysis (DMA) and rubber process analysis (RPA) measurements seem to be similar. Between the analogous dynamic mechanical characteristics from DMA and from RPA usually a linear relationship exists with high correlation coefficient.

Conclusions derived from DMA and RPA testing on the same series of rubber compounds seem to be the same. Copyright © 2006 John Wiley & Sons, Ltd.
Study of adhesion and surface properties of low‐density poly(ethylene) pre‐treated by cold discharge plasma
Authors: Novák Igor , Števiar Marián , Chodák Ivan , Krupa Igor , Nedelčev Tomáš , Špírková Milena , Chehimi Mohamed M. , Mosnáček Jaroslav , Kleinová Angela
Published: December 2006

The low‐density poly(ethylene), which is prone to hydrophilicity, dyeability, and bondability, was modified by surface barrier discharge and radio‐frequency discharge plasma. A process of plasma modification was investigated to improve adhesion between poly(ethylene) and more polar polymers, to improve surface properties, and to form a new surface containing polar functional groups incoming to reactions with diazo‐compounds, and/or vinyl silanes. The measurements of contact angles and peel strengths of adhesive joints were carried out for characterization of the surface and adhesive properties of the polymer modified by plasma. The topography of modified poly(ethylene) was studied using atomic force microscopy, and changes in chemical structure were analyzed with X‐ray photoelectron spectroscopy. Copyright © 2006 John Wiley & Sons, Ltd.
A new polymeric silicone hydrogel for medical applications: synthesis and properties
Authors: Chekina N. A. , Pavlyuchenko V. N. , Danilichev V. F. , Ushakov N. A. , Novikov S. A. , Ivanchev S. S.
Published: December 2006

A novel silicone hydrogel polymeric material is developed. The preparation method is based on sequential interpenetrating network synthesis. A silicone network is obtained by the interaction between two siloxane oligomers comprising hydride and vinyl functional groups. A hydrophilic network is prepared by radical copolymerization of hydrophilic monomers (N‐vinyl pyrrolidone, N,N‐dimethylacrylamide) and crosslinking agent (ethylene glycol dimethacrylate). In the hydrated state the developed material has high mechanical properties, transparency, hydrophilicity, oxygen and water permeability. The developed new technology affords obtaining a silicone hydrogel material with a good wettability without additional chemical or plasma surface treatment. Copyright © 2006 John Wiley & Sons, Ltd.
Optimization of monosize/cationic nanoparticle synthesis and their interaction with genomic DNA
Authors: Güven G. , Pişkin E.
Published: December 2006

Monosized poly(styrene/poly(ethylene glycol) ethyl ether methacrylate/N‐[3‐(dimethyl‐amino)propyl]methacrylamide) [poly(St/PEG‐EEM/DMAPM)] monosize cationic nanoparticles were produced by emulsifier‐free microemulsion polymerization conducted in the presence of a cationic initiator, 2,2′‐azobis(2‐methylpropionamidine)dihydrochloride (V‐50), in which polymerization temperature, time and pH were changed. Particle sizes and surface charge densities were measured with a Zeta Sizer. Atomic force microscopy (AFM) was also used for measurement of particle size. The nanoparticles with the minimum size of 77.6 nm and with quite narrow size distributions (PI  =  0.125), and with a zeta potential of about 54.4 mV (cationic) were produced by this method. The optimal temperature, time and pH were 60°C, 3 hr and 2.5–3.0, respectively. It was possible to bind about 200 mg DNA per gram of nanoparticles at room temperature, in 2 hr in the pH range 3–8. Copyright © 2006 John Wiley & Sons, Ltd.
Genetic intra‐tumour heterogeneity in epithelial ovarian cancer and its implications for molecular diagnosis of tumours
Authors: Khalique L , Ayhan A , Weale ME , Jacobs IJ , Ramus SJ , Gayther SA
Published: December 2006

Genetic analysis of solid tumours using DNA or cDNA expression microarrays may enable individualized treatment based on the profiles of genetic changes that are identified from each patient. This could result in better response to adjuvant chemotherapy and, consequently, improved clinical outcome. So far, most research studies that have tested the efficacy of such an approach have sampled only single areas of neoplastic tissue from tumours; this assumes that the genetic profile within solid tumours is homogeneous throughout. The aim of this study was to evaluate the extent of genetic intra‐tumour heterogeneity (ITH) within a series of epithelial ovarian cancers. Several different regions (five to eight regions) of tumour tissue from 16 grade 3, serous epithelial ovarian cancers were analysed for genetic alterations using a combination of microsatellite analysis and single nucleotide polymorphism (SNP) analysis, in order to establish the extent of ITH. Maximum parsimony tree analysis was applied to the genetic data from each tumour to evaluate the clonal relationship between different regions within tumours. Extensive ITH was identified within all ovarian cancers using both microsatellite and SNP analysis. Evolutionary analysis of microsatellite data suggested that the origin of all tumours was monoclonal, but that subsequent clonal divergence created mixed populations of genetically distinct cells within the tumour. SNP analysis suggested that ITH was not restricted to random genetic changes, but affected genes that have an important functional role in ovarian cancer development. The frequent occurrence of ITH within epithelial ovarian cancers may have implications for the interpretation of genetic data generated from emerging technologies such as DNA and mRNA expression microarrays, and their use in the clinical management of patients with ovarian cancer. The basis of genetic ITH and the possible implications for molecular approaches to clinical diagnosis of ovarian cancers may apply to other tumour types. Copyright © 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Human placental lactogen is a first‐trimester maternal serum marker of Down syndrome
Authors: Christiansen Michael , Sørensen Tina Lindvig , Nørgaard‐Pedersen Bent
Published: December 2006

Background

Human placental lactogen (hPL) is synthesised by the placenta and found in maternal serum. We analysed the potential of hPL as a first‐trimester maternal serum‐screening marker for fetal Down syndrome (DS).

Materials and Methods

hPL was quantified by ELISA in 47 DS pregnancies and 136 controls in gestational weeks 8–13. Distributions of log multiples of the median (MoMs) were established. The quantity of hPL in DS screening was estimated using Monte Carlo simulation methods.

Results

The mean log10 MoM hPL was − 0.1995 (SD: 0.1993) in affected and 0.0026 (SD: 0.2129) in control pregnancies. This corresponds to a MoM of 0.63 in DS pregnancies. hPL correlated significantly with log10 MoM values of hCGβ (r = 0.320) and PAPP‐A (r = 0.590) in controls, but not with hCGβ (r = 0.228) or PAPP‐A (r = 0.090) in DS pregnancies. The inclusion of hPL in the double test (PAPP‐A + hCGβ) increased the detection rate from 67 to 75% for a false‐positive rate of 5%.

Conclusion

hPL is a DS screening marker that is applicable at weeks 9–13 and could be included in multiple marker first‐trimester screening for DS. Copyright © 2007 John Wiley & Sons, Ltd.
Non‐invasive prenatal detection of achondroplasia in size‐fractionated cell‐free DNA by MALDI‐TOF MS assay
Authors: Li Ying , Page‐Christiaens Godelieve C. M. L. , Gille Johan J. P. , Holzgreve Wolfgang , Hahn Sinuhe
Published: December 2006

Achondroplasia is the most common form of short‐limbed dwarfism in humans and is caused by mutations in the FGFR3 gene. Currently, prenatal diagnosis of this disorder relies on invasive procedures. Recent studies have shown that fetal single gene point mutations could be detected in cell‐free DNA (cf‐DNA) from maternal plasma by either the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) assay with single allele base extension reaction (SABER) approach or the size fractionation of cf‐DNA in maternal plasma. Here, we combined the two approaches to non‐invasively examine the fetal G1138A mutation in maternal plasma.

cf‐DNA was extracted from maternal plasma samples obtained from two pregnant women at risk for achondroplasia. The fetal G1138A mutation was determined by the analysis of size‐fractionated cf‐DNA in maternal plasma using MALDI‐TOF MS with SABER approach and homogenous MassEXTEND (hME) assay, respectively.

The fetal G1138A mutation was detectable in the two achondroplasia‐affected pregnancies by the analysis of cf‐DNA in maternal plasma using MALDI‐TOF MS. However, the size‐fractionation approach led to a more precise detection of the fetal mutation in both analyses.

This analysis would be suitable for non‐invasive prenatal diagnosis of diseases caused by fetal single gene point mutations. Copyright © 2007 John Wiley & Sons, Ltd.
False positives in the prenatal ultrasound screening of fetal structural anomalies
Authors: Martinez‐Zamora M. Angels , Borrell Antoni , Borobio Virginia , Gonce Anna , Perez Marimer , Botet Francesc , Nadal Alfons , Albert Asteria , Puerto Bienvenido , Fortuny Albert
Published: December 2006

Objective

To describe the false‐positive diagnoses of prenatal ultrasound screening of fetal structural anomalies.

Methods

Pregnancies with fetal structural anomalies either detected prenatally in our center or referred to us, were registered, evaluated, and followed‐up prospectively by a multidisciplinary Congenital Defects Committee. After postnatal follow‐up was completed, cases were assigned as true positives, false positives or false negatives and categorized by anatomical systems. Pregnancies referred with a nonconfirmed suspicion of anomaly were not included. The false‐positive diagnoses were analyzed.

Results

From 1994 to 2004, 903 new registry entries of fetuses structurally abnormal at ultrasound with a complete follow‐up were included in the Committee database. There were 76 false positives, accounting for 9.3% of all the prenatally established diagnoses. The urinary tract anomalies were the most frequent false‐positive diagnoses found (n = 25; accounting for 8.7% of the urinary tract defects), but the genital anomalies showed the higher rate of no confirmation (n = 5; 15.2%). The specific anomalies most commonly not confirmed were renal pyelectasis (n = 9), cerebral ventriculomegaly (n = 9), abdominal cysts (n = 7) and short limbs (n = 7).

Conclusion

Several prenatally diagnosed anomalies would benefit from prudent counseling, because they may be normal variants or transient findings. Copyright © 2007 John Wiley & Sons, Ltd.
Fetal cardiomyopathy—in utero evaluation and clinical significance
Authors: Yinon Yoav , Yagel Simcha , Hegesh Juluis , Weisz Boaz , Mazaki‐Tovi Shali , Lipitz Shlomo , Achiron Reuven
Published: December 2006

Objective

To describe the prenatal diagnosis and outcome of fetal cardiomyopathy (CM).

Methods

The charts, photographs and videotapes of all fetuses with CM, who were assessed during pregnancy at two referral centers, were reviewed.

Results

The diagnosis of CM was established in 12 fetuses. All had structurally normal hearts, and all cases were diagnosed after 23 weeks of gestation, following normal early fetal echocardiogram. Three clusters of fetal CM appeared:

Familial—two sib fetuses of a mother, who is a second generation of CM. Both had dilated CM and pathological findings were consistent with the diagnosis of endocardial fibroelastosis.

Secondary—CM that was induced by another factor.

Idiopathic—six cases of CM without an underlying specific etiology

Three women elected to terminate their pregnancy. Among the nine who delivered, four had a favorable outcome with normal cardiac function at the age of 1 month, in which three belonged to the secondary category, and five cases were complicated by fetal/infant death.

Conclusions

CM may develop during fetal life and might be diagnosed by prenatal echocardiography. Normal cardiac findings in a midtrimester fetus do not exclude subsequent development of CM. Detailed prenatal sonographic examination may aid in determining the neonatal outcome. Copyright © 2007 John Wiley & Sons, Ltd.