bluuebunny/crossref_metadata_2025 huggingface dataset:
An Introduction to Hidden Markov Models
Authors: Schuster‐Böckler Benjamin , Bateman Alex
Published: June 2007

This unit introduces the concept of hidden Markov models in computational biology. It describes them using simple biological examples, requiring as little mathematical knowledge as possible. The unit also presents a brief history of hidden Markov models and an overview of their current applications before concluding with a discussion of their limitations.
Genetic Manipulation of Leptospira biflexa
Authors: Louvel Hélène , Picardeau Mathieu
Published: June 2007

The genus Leptospira belongs to the order Spirochaetales and is composed of both saprophytic and pathogenic members, such as Leptospira biflexa and L. interrogans, respectively. A major factor contributing to our ignorance of spirochetal biology has been the lack of methods available for genetic analysis of these organisms. In recent years, an E. coli‐L. biflexa shuttle vector has been constructed and a system for targeted mutagenesis and random transposon mutagenesis of the saprophyte L. biflexa has been developed. These studies enable the use of L. biflexa as a model bacterium among spirochetes.
Preparation of Rectangular WO3·H2O Nanotubes Under Mild Conditions
Authors: Wang Z. , Zhou S. , Wu L.
Published: June 2007

WO3·H2O nanotubes are successfully synthesized with the aid of intercalated polyaniline (PANI) under relatively mild conditions. More interestingly, the WO3·H2O nanotubes have a rectangular cross‐section structure formed through a rolling mechanism. Scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, thermogravimetric analysis, Fourier‐transform infrared analysis, UV‐vis‐near‐IR spectroscopy, selected‐area electron diffraction, and vibrating‐sample magnetometry analysis are employed to characterize the morphology, structure, and properties of the nanotubes.
Expert consensus ratings of job categories from the Third National Health and Nutrition Examination Survey (NHANES III)
Authors: D'Souza Jennifer C. , Keyserling W. Monroe , Werner Robert A. , Gillespie Brenda , Franzblau Alfred
Published: June 2007

Background

A method of occupational physical exposure assessment is needed to improve analyses using large data sets (e.g., national surveys) that provide only job title/category information as a proxy for exposure.

Methods

Five ergonomic experts rated and arrived at consensus ratings for job categories used in the Third National Health and Nutrition Examination Survey. Interrater agreement was examined for initial (pre‐consensus) ratings. Correlation between consensus ratings and an independent source of ratings (US Department of Labor (DOL)) was used as a basis of comparison.

Results

Interrater agreements for the initial ratings were weak. Highest interrater agreement was for sitting (weighted kappa (κw) = 0.56). Lowest agreement was for standing (κw = 0.07). Consensus ratings were well correlated with DOL ratings (correlation coefficients ≥0.6).

Conclusions

The correlation between consensus ratings and DOL ratings support the use of expert consensus to assess physical exposures in national data sets. However, validation of expert consensus ratings is required. Am. J. Ind. Med. 50:608–616, 2007. © 2007 Wiley‐Liss, Inc.
Cold exposure and low back pain in store workers in Israel
Authors: Dovrat Eva , Katz‐Leurer Michal
Published: June 2007

Background

In recent years the demand for frozen food in the Western world has been growing, and the number of cold storeroom has increased proportionately. There are very few studies documenting cold exposure as a risk factor for musculoskeletal symptoms (MSS). This study describes the prevalence of MSS, in particular low back pain (LBP) among cold storeroom workers in Israel and explores the connection between exposure to cold at work and MSS.

Methods

A cross‐section survey included 122 males between the ages of 20–45 who had been employed for at least 1 year in three food stores in Israel. The subjects were classified as an exposed group working at temperatures of −20°C and a control group working at room temperatures (20°C to 25°C). The prevalence rate of MSS, in particular LBP, was assessed using the Standardized Nordic Questionnaire.

Results

Cold storeroom workers had increased odds of reporting back symptoms in the previous 12 months (odds ratio (OR) = 2.9, 95% CI = 1.3–6.7) and during work (OR = 4.8, 95% CI = 1.8–13.0) compared with their colleagues working in storerooms at regular temperatures. Among workers who described themselves as satisfied at work, the cold storeroom workers had increased odds of reporting back symptoms in the last 12 months and during work (OR = 3.9, 95% CI = 1.5–10.6, OR = 9.4, 95% CI = 2.0–44.6, respectively) while there was no association between store type and LBP among dissatisfied workers.

Conclusions

The results of this study strengthen the hypothesis that workers in cold environments are at a greater risk of LBP. Am. J. Ind. Med. 50:626–631, 2007. © 2007 Wiley‐Liss, Inc.
Fluoride effect on the palladium–phenanthroline catalyzed carbonylation of nitroarenes to carbamates
Authors: Gasperini Michela , Ragaini Fabio , Cenini Sergio , Gallo Emma , Fantauzzi Simone
Published: June 2007

Fluorides promote the palladium–phenanthroline catalyzed carbonylation of nitroarenes to carbamates. The effect is more evident on the rate of the reaction at short reaction times, but a positive effect on selectivity is also observed under certain conditions. The effect is observed even under conditions under which chloride inhibits the reaction. Tetraethylammonium is a better countercation than sodium. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of oxidation time on the structure and properties of polyacrylonitrile‐based activated carbon hollow fiber
Authors: Sun Junfen , He Chunju , Zhu Sijun , Wang Qingrui
Published: June 2007

Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of oxidation time of PAN hollow fiber precursor on the microstructure, specific surface, pore size distribution, and adsorption properties of PAN‐based activated carbon hollow fiber (PAN‐ACHF) were studied in this work. Both of specific surface area and adsorption ratio to VB12 reach maximums when PAN hollow fibers are oxidized for 5 h in air. The adsorption ratios for creatinine are all higher than 90% over all oxidation time. After 5 h of oxidation, the number of pores on the surface obviously increases, and the pore size is uniform. After 7 h of oxidation, the number of macropores in PAN‐ACHF increases. The dominant pore sizes of mesopores in PAN‐ACHF range from 2 to 5 nm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Segmental dynamics of reactively prepared polystyrene blends: Unsaturated polyester resin versus high impact polystyrene
Authors: Qazvini N. Taheri , Mohammadi N.
Published: June 2007

Segmental dynamics of two phase‐separated reactively prepared polystyrene blends namely unsaturated polyester resin (UPR) and high impact polystyrene (HIPS) was investigated by dynamic–mechanical spectroscopy and calorimetric studies. The results showed a thermorheologically simple behavior for the HIPS, which could be quantified based on the KWW function with βKWW of 0.37. The UPR data, however, could not be evaluated using KWW function, even though lower βKWW than the HIPS was expected for it. Furthermore, the α‐dispersion of the UPR was considerably broader while its fragility index was comparable with the HIPS. Nonetheless, segmental dynamics comparison based on normalized ΔCp(Tg) by molecular weight of the structural units of the studied systems showed much greater differences. Accordingly, the UPR was both kinetically and thermodynamically more fragile than the HIPS. The higher fragility of the UPR could be attributed to its larger relative cooperativity size and topological constraints. Finally, enhanced contrast in dynamic fragilities of two studied systems could be achieved if similar overall and local compositions could be made experimentally. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Novel pyridinium photoinitiators and their applications for the ultraviolet crosslinking of acrylic pressure‐sensitive adhesives
Authors: Czech Zbigniew , Gąsiorowska M. , Soroka Jacek
Published: June 2007

The demand for ultraviolet (UV)‐crosslinkable pressure‐sensitive adhesives (PSAs) has rapidly been increasing. A variety of different PSAs containing new photoreactive pyridinium derivatives have been evaluated for their effectiveness in improving adhesion and cohesion in UV‐crosslinkable PSAs. PSAs have been evaluated with respect to the tack, peel adhesion, and shear strength. This article summarizes the breakthrough technology used to achieve better performances in UV‐crosslinkable acrylic PSAs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Patterning of thin poly(N‐vinyl pyrrolidone) films on silicon substrates by electron beam lithography
Authors: Burkert Sina , Schmidt Thomas , Gohs Uwe , Mönch Ingolf , Arndt Karl‐Friedrich
Published: June 2007

Poly(N‐vinyl pyrrolidone) (PVP) is a widely used biocompatible polymer. PVP can be crosslinked by electron beam irradiation even in dry state. In contact with water it forms hydrogels. In a previous work we analyzed the crosslinking behavior of PVP bulk gels and thin PVP films on silicon wafers under electron beam irradiation. In this work, we applied the electron beam lithography on dry PVP films. Different patterns with a width of less than 100 nm were written into the film with the e‐beam of a scanning electron microscope. The topography of the patterned film is investigated by atomic force microscopy. For further applications, we tried to create a gradient of crosslinking density within the film using a combination of e‐beam irradiation and e‐beam lithography. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Ionic mechanisms in pulse irradiated poly(vinyl chloride) system containing stabilizing additives
Authors: Mayer J. , Szadkowska‐Nicze M.
Published: June 2007

The pulse radiolysis studies of poly(vinyl chloride), PVC, film containing stabilizers i.e., Tinuvin P, Irgastab PVC 11, and Irganox 1076 have been carried out with the main aim of investigating ionic reactions in these systems. The evidences are presented concerning the formation of ionic transients in model solvents i.e. 2‐propanol and sec‐butyl chloride as well as in PVC film. In PVC‐stabilizer system under consideration the additives can contribute to the positive charge transfer processes whereas Tinuvin P, in addition may scavenge effectively electrons (the rate constant for e−solv scavenging in 2‐propanol equals 5.9 × 109 mol−1 dm3 s−1) influencing the negative charge scavenging by PVC matrix itself and the HCl formation during the radiolysis of PVC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Thermal energy transport within porous polymer materials: Effects of fiber characteristics
Authors: Wu Huijun , Fan Jintu , Du Ning
Published: June 2007

A theoretical model integrating the radiative and conductive heat transfer is presented and applied to evaluate the thermal energy transport within porous polymer materials. The model was first validated by comparing the computed thermal energy flux with the experimental measurements of two porous polymer materials made of wool and polyester. The model was then used to predict the effects of the polymer fiber characteristics (viz. fiber fractional volume, fiber emissivity, fiber radius, and fiber thermal conductivity) on the thermal energy flux within the porous polymer materials. It was found that decreasing fiber radius would significantly reduce the total thermal energy flux through the porous polymer materials, whereas increasing fibre emissivity or decreasing the thermal conductivity would cause a just slight reduction of the total thermal energy flux. The fiber fractional volume had a significant influence on the thermal energy flux, and thereby the fiber fractional volume can be optimized in view of improving the thermal insulating performance of the porous polymer materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Molecular dynamics of poly(glycolide‐co‐L‐lactide) copolymer during isothermal cold crystallization
Authors: Kortaberria G. , Jimeno A. , Arruti P. , Arbelaiz A. , Mondragon I.
Published: June 2007

Poly(glycolide‐co‐l‐lactide) (PGA/PLLA) is a random copolymer with 92 wt % PGA, being the basic resin for Vicryl® suture. Molecular dynamics of PGA/PLLA in its wholly amorphous state and during isothermal cold crystallization at 70 and 80°C have been analyzed. Experimental results were generated over a wide range of frequency and temperature by broad‐band dielectric spectroscopy (DRS). The variation of the average relaxation time (defined as τ = [1/2]πfmax where fmax is the frequency at maximum loss for the main α relaxation) has been studied during cold crystallization and the temperature dependence of this average relaxation time for wholly amorphous and crystallized samples has been analyzed. This behavior has been modeled by Havriliak–Negami, Vogel–Fulcher–Tammann, and Kohlrausch–Williams–Watts equations. The evolution profile of the dynamics (frequency at which the maximum loss appears, fmax) depends on the crystallization temperature, being different at 80°C relatively to 70°C, which could reflect different progress of the spherulitic morphology, as it is shown by the evolution of the morphologies obtained during the crystallization processes, followed by optical microscopy. While the loss maximum (and consequently relaxation times) remains almost unmodified during the crystallization process at 70°C, for the process at 80°C the maximum first moves slightly to higher frequencies (shortening of relaxation times) and at the final stages of crystallization it moves to lower frequencies (increasing the relaxation times). Supporting evidence about the thermal behavior of the polymers has been obtained with DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Surface photografting polymerization of trimethylolpropane triacrylate onto LDPE substrate in tetrahydrofuran/water mixtures
Authors: Wang Lifu , Yu Yibing , Liu Lianying , Yang Wantai
Published: June 2007

A surface photografting polymerization (λ > 300 nm) of a multifunctional monomer which was trimethylolpropane triacrylate (TMPTA), was conducted with benzophenone (BP) as photoinitiator and LDPE as model substrate, in mixed solvents containing tetrahydrofuran (THF) and water. Proved by ATR‐IR, highly crosslinked grafted layer was generated rapidly under UV irradiation. Effects on percent conversion of grafting are detailed with, such as feed ratio of BP to TMPTA, mass percent of TMPTA in the reaction system, mass percent of water in the mixed solvents and addition of the second monomer, methyl methacrylate (MMA). As both verified by SEM and AFM, relatively planar grafted layer was produced when photografting was carried out merely in THF; adding water in the reaction system caused the formation of “craters” in the grafted layer. In addition, effects of mass percent of water in the mixed solvents, UV irradiation time, TMPTA concentration and addition of MMA on the size, shape and quantity of the “craters” were investigated by SEM. A plausible mechanism for the formation of “craters” is also proposed. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Rheology, thermal characteristics, crystallinity, tenacity and density of cationic dyeable polycaproamide/cationic dyeable poly(trimethylene terephthalate) polyblended fibers
Authors: Shu Yao‐Chi , Hsiao Kai‐Jen
Published: June 2007

Cationic dyeable polycaproamide (CD‐PCA) and cationic dyeable poly(trimethylene terephthalate) (CD‐PTT) polymers were extruded (in ratios 75/25, 50/50, and 25/75) from one melt twin‐screw extruders to prepare three CD‐PCA/CD‐PTT polyblended polymers and then spin fibers. This work examines the rheology, thermal characteristics, crystallinity, tenacity, density, and miscibility parameter μ value of CD‐PCA/CD‐PTT polyblended polymers and fibers using gel permeation chromatography, differential scanning calorimetry, thermogravimetric analysis, potentiometer, rheometer, the density gradient analysis, wide‐angle X‐ray diffraction, and extension stress–strain measurement. The melting behavior of CD‐PCA/CD‐PTT polyblended polymers revealed negative‐deviation blends (NDB). The 50/50 blend of CD‐PCA/CD‐PTT had the lowest melt viscosity. The experimental DSC results demonstrated that CD‐PCA and CD‐PTT molecules constituted an immiscible system. In particular, CD‐PCA, CD‐PTT, and their polyblended fibers yielded a double endothermic peak. The tenacity of CD‐PCA/CD‐PTT polyblended fibers initially declined and then increased as the CD‐PTT content increased. The crystallinities and densities of CD‐PCA/CD‐PTT polyblended fibers were linearly related to the blend ratio. The values of the miscibility parameter μ for all CD‐PCA/CD‐PTT samples were under zero, revealing electrostatic repulsion between CD‐PCA and CD‐PTT molecules. All experimental data supported the immiscibility of CD‐PCA/CD‐PTT polyblended fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Effect of Co2+, Ni2+, Cu2+, or Zn2+ on properties of polyaniline nanoparticles
Authors: Zhou Su , Wu Tao , Kan Jinqing
Published: June 2007

Uniform polyaniline (PANI) nanoparticles with typical sizes of about 50 nm were electropolymerized on indium tin oxide surfaces in the presence of Co2+, Ni2+, Cu2+, or Zn2+. According to shaping theory, we first suggest the reason forming PANI spherical particles. Their conductivity, UV‐vis spectra, FTIR spectra, X‐ray diffraction, and thermogravimetric analysis were investigated. The conductivities and crystallinity of PANI doped with these ions are higher than those of PANI doped with HCl (PANI/HCl). Both UV‐vis absorption spectra and FTIR spectra indicate the interactions between Co2+, Ni2+, Cu2+, or Zn2+ and PANI chains. TG analysis also shows that the thermal stability of PANI doped by Co2+, Ni2+, Cu2+, or Zn2+ is lower than that of PANI/HCl. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Zur Größe und Struktur des Fehlers der Betondruckfestigkeit
Authors: Sieber Edgar
Published: June 2007

Der Fehler bzw. die Streuung der Betondruckfestigkeit wird in den Zusammenhang des Sicherheitskonzepts der Grenzzustände gestellt. Die Fehlerbestandteile werden beschrieben und mittels statistisch gestützter mathematischer Fehleranalyse quantitativ bestimmt. Die Anteile der Teilfehler am Gesamtfehler und deren charakteristischer Verlauf werden gezeigt. Die Anwendung der Fehlergleichungen ermöglicht die schnelle Darstellung der Festigkeitsstreuungen.
Betonbau im Atlantik – das Imarsundprojekt
Authors: Blaschko Michael , Torka Jan
Published: June 2007

Die Imarsundquerung, von den Norwegern im Jahr 2005 zum Bauwerk des Jahrhunderts gekürt, stellt die geographische Verlängerung der legendären Atlantikstraße an der Norwegischen Westküste dar. Seit der Verkehrsfreigabe am 15. Januar 2007 ersetzt die neue Verbindung den Fährbetrieb zwischen den Inseln Stabblandet (Aukan) und Jørnøya, die bisher nur per Schiff zu erreichen waren, mit der Insel Ertvågøya auf einer Länge von 5,3 km. Die beiden Straßenbrücken über den Imarsund und den Litjsund bilden dabei das Herzstück der Imarsundverbindung. Der vorliegende Artikel beschreibt die Herstellung der Stahlbetonfundamente im Meer. Bauen im Atlantik bedeutet dabei nach wie vor harsche Bedingungen für Mannschaft und Geräte.
Enantioselective HPLC‐UV method for determination of eslicarbazepine acetate (BIA 2‐093) and its metabolites in human plasma
Authors: Alves Gilberto , Figueiredo Isabel , Castel‐Branco Margarida , Loureiro Ana , Fortuna Ana , Falcão Amílcar , Caramona Margarida
Published: June 2007

Eslicarbazepine acetate (BIA 2‐093) is a novel central nervous system drug undergoing clinical phase III trials for epilepsy and phase II trials for bipolar disorder. A simple and reliable chiral reversed‐phase HPLC‐UV method was developed and validated for the simultaneous determination of eslicarbazepine acetate, oxcarbazepine, S‐licarbazepine and R‐licarbazepine in human plasma. The analytes and internal standard were extracted from plasma by a solid‐phase extraction using Waters Oasis® HLB cartridges. Chromatographic separation was achieved by isocratic elution with water–methanol (88:12, v/v), at a flow rate of 0.7 mL/min, on a LichroCART 250‐4 ChiraDex (β‐cyclodextrin, 5 µm) column at 30°C. All compounds were detected at 225 nm. Calibration curves were linear over the range 0.4–8 µg/mL for eslicarbazepine acetate and oxcarbazepine, and 0.4–80 µg/mL for each licarbazepine enantiomer. The overall intra‐ and interday precision and accuracy did not exceed 15%. Mean relative recoveries varied from 94.00 to 102.23% and the limit of quantification of the assay was 0.4 µg/mL for all compounds. This method seems to be a useful tool for clinical research and therapeutic drug monitoring of eslicarbazepine acetate and its metabolites S‐licarbazepine, R‐licarbazepine and oxcarbazepine. Copyright © 2007 John Wiley & Sons, Ltd.
Organizing motions with a nominal description
Authors: Park Min Je , Cho Jieun
Published: June 2007

Due to the success of motion capture technologies, large motion capture data become available. Although organizing large databases has been widely researched for various purposes, there is little attention to motion capture data. In this paper, we propose an effective scheme to organize large motion databases according to its nominal features. To do this, we first define a set of attributes and its corresponding values to form a set of attribute‐value pairs. Each attribute represents a visual characteristic of human motion. We adopt machine learning algorithms to assign a specific value to the attribute. Then, we categorize all motions in database according to the set of attribute‐value pairs. Since attributes define nominal properties rather than numerical ones, we adopt a conceptual clustering algorithm based on formal concept analysis (FCA). After clustering, we can acquire a clustering dendrogram called classification tree that characterizes each cluster with a probabilistic description. We present experimental results to show the effectiveness of our scheme for organizing large motion database. Copyright © 2007 John Wiley & Sons, Ltd.
Temporal texture synthesis by patch‐based sampling and morphing interpolation
Authors: Lai Chao‐Hung , Wu Jiunn‐Lin
Published: June 2007

We present a new algorithm for synthesizing temporal textures, which is simple and requires only a static texture image as input to produce a continuous varying stream of realistic images. We first introduce the basis sequence generation procedure in which the chosen patches from the input texture image are stitched on the output frame via blended alpha mattes formed by minimum error cuts. All the frames in the generated basis sequence are toroidal. We then employ the probabilities of similarity and transition links to generate an inexhaustible sequence with quasi‐periodic quality. To ensure the smoothness of frame‐to‐frame transition, we interpolate natural metamorphosis in each transition link using the efficient automatic morphing technique which solves the problem of morphing between chaotic textures with obscure features. In addition, the proposed method allows users to simply and promptly control the motion parameters and interactively render the landscape animations. We combine the proposed approach with the color transfer technique to augment the visual gratification. Several examples including scenes for cloud, fire, and water are presented to demonstrate that the proposed algorithm is simple, efficient, and controllable for synthesizing temporal textures. Copyright © 2007 John Wiley & Sons, Ltd.
Polyamide Synthesis from 6‐Aminocapronitrile, Part 1: N‐Alkyl Amide Formation by Amine Amidation of a Hydrolyzed Nitrile
Authors: van Dijk Adrianus J. M. , Heyligen Tom , Duchateau Robbert , Meuldijk Jan , Koning Cor E.
Published: June 2007

The synthesis of N‐hexylpentanamide from a stoichiometric amount of pentanenitrile and hexylamine has been studied as a model reaction for the synthesis of nylon‐6 from 6‐aminocapronitrile. The reaction was carried out under mild hydrothermal conditions and in the presence of a homogeneous ruthenium catalyst. For the mild hydrothermal conditions the presence of hexylamine distinctively increases the nitrile hydrolysis compared to the nitrile hydrolysis in the absence of hexylamine. Amine‐catalyzed nitrile hydrolysis mainly produces the N‐substituted amide. A clear product development is observed, consisting of first the terminal amide formation and second the accumulation of N‐hexylpentanamide. With a maximum conversion of only 80 % after 18 h, the nitrile hydrolysis rate at 230 °C is still much too low for nylon‐6 synthesis. Ruthenium dihydride phosphine was therefore used as a homogeneous catalyst, which significantly increases the nitrile hydrolysis rate. At a temperature of 140 °C and with only 0.5 mol % [RuH2(PPh3)4] a 60 % nitrile conversion is already reached within 2 h. Initially the terminal amide is the sole product, which is gradually converted into N‐hexylpentanamide. The reaction has a high initial rate, however, for higher conversions a strong decrease in hydrolysis rate is observed. This is ascribed to product inhibition, which results from the equilibrium nature of the reaction.
Polyamide Synthesis from 6‐Aminocapronitrile, Part 2: Heterogeneously Catalyzed Nitrile Hydrolysis with Consecutive Amine Amidation
Authors: van Dijk Adrianus J. M. , Duchateau Robbert , Hensen Emiel J. M. , Meuldijk Jan , Koning Cor E.
Published: June 2007

To test the potential of heterogeneous catalysts for the nylon‐6 synthesis from 6‐aminocapronitrile, a number of zeolites, aluminum silicate, and metal oxides were tested as catalysts for the model reaction of pentanenitrile with water and hexylamine to N‐hexylpentanamide. All zeolitic and aluminum silicate systems showed an insufficient performance, while the metal oxides (TiO2, ZrO2, Nb2O5) showed very promising results. The kinetic behavior of the metal oxides was further investigated. First the nitrile was catalytically hydrolyzed to the terminal amide and subsequently the amidation of the hexylamine occurred. To polymerize 6‐aminocapronitrile into nylon‐6, more than 99 % nitrile conversion was required to obtain a high‐molecular‐weight polymer. Pentanenitrile conversions larger than 99 % can be obtained within six hours, at 230 °C, by using ZrO2 as the catalyst. A kinetic study (by using IR spectroscopy) on the behavior of the metal oxides demonstrated that the adsorbed nitrile was catalytically hydrolyzed at the surface, but remained tightly bound to the surface. Zirconia‐catalyzed polymerizations of 6‐amino‐capronitrile demonstrated that high‐molecular‐weight nylon‐6 is feasible by using this route.
A Study of (Binap)(enyne)tetracarbonyldicobalt(0) Complexes
Authors: Gibson Susan E. , Hardick David J. , Haycock Peter R. , Kaufmann Karina A. C. , Miyazaki Ayako , Tozer Matthew J. , White Andrew J. P.
Published: June 2007

Four (binap)(enyne)tetracarbonyldicobalt(0) complexes have been synthesised and their reactivity monitored by variable temperature 31P NMR spectroscopy. Formation of (binap)dicarbonylhydridocobalt(−1) 12 occurred at temperatures between 35 and 55 °C, depending on the nature of the alkene and alkyne components of the enyne. The structure of 12 was determined by X‐ray crystallography, and its presence under Pauson–Khand reaction conditions was verified by NMR spectroscopy.
Elevated circulating endothelial progenitor marker CD133 messenger RNA levels predict colon cancer recurrence
Authors: Lin Edward H. , Hassan Manal , Li Yanan , Zhao Hua , Nooka Ajay , Sorenson Elizabeth , Xie Keping , Champlin Richard , Wu Xifeng , Li Donghui
Published: June 2007

BACKGROUND.

CD133 is a specific surface marker for bone marrow‐derived circulating endothelial progenitors, which are vital in postnatal physiologic and pathologic (eg, tumor) angiogenesis. In this study, the authors examined whether increased levels of expression of CD133 messenger RNA (mRNA) in peripheral blood predicted disease recurrence in patients with colon cancer.

METHODS.

Semiquantitative real‐time reverse transcriptase‐polymerase chain reaction analysis was used to quantify CD133 mRNA levels in peripheral blood mononuclear cells from patients with colon cancer. The assay was developed first and tested at laboratory A (n = 34) and then was validated independently at laboratory B (n = 66). All patients were enrolled between February 2002 and December 2003. A central statistician performed the analysis.

RESULTS.

At laboratory A, the median CD133 mRNA level was elevated in patients with recurrent disease (4.2; range, 0.017–106.9) compared with patients without recurrence (0.0017; range, 0.0–9.51; P < .001), leading to a 14.6 odds ratio of recurrence (95% confidence interval [95% CI], 1.7–126; P = .004). At laboratory B, it was confirmed that elevated CD133 mRNA levels at a cutoff point ≥4.79 versus <4.79 were associated with an odds ratio of 22.6 for recurrence (95% CI, 1.7–291.2; P = .02). By comparison, the odds ratio for recurrence was 17.2 (95% CI, 1.8–164; P = .01) for patients with stage III–IV disease versus stage I–II disease according to the Tumor, Lymph Node, Metastasis (TNM) classification. An association also was observed between elevated carcinoma embryonic antigen levels (P = .03; 1‐sided) and decreased survival (P = .035; 1‐sided) with a CD133 mRNA cutoff level of ≥4.79.

CONCLUSIONS.

Elevated CD133 mRNA levels at ≥4.79 predicted colon cancer recurrence independent of TNM stage IV disease. Larger prospective studies comparing the current assay with standardized methodology are warranted. Cancer 2007. © 2007 American Cancer Society.
Meta–analyses of the association between Chlamydia psittaci and ocular adnexal lymphoma and the response of ocular adnexal lymphoma to antibiotics
Authors: Husain Amina , Roberts Dianna , Pro Barbara , McLaughlin Peter , Esmaeli Bita
Published: June 2007

BACKGROUND.

There are conflicting reports regarding the association between Chlamydia psittaci (Cps) and ocular adnexal lymphoma (OAL) and the efficacy of antibiotics for OAL. In the current study, the authors attempted to clarify the association between Cps and OAL and the efficacy of antibiotics for OAL.

METHODS.

Two meta‒analyses were conducted. One focused on the association between Cps and OAL across geographic regions and among different studies. The other was a meta‒analysis of the response of OAL to antibiotic treatment.

RESULTS.

The authors identified 11 studies of Cps prevalence that included 458 cases of OAL from 10 different countries. Four studies regarding the efficacy of oral antibiotics to treat OAL were found. One hundred four of the 458 OAL specimens (23%) and 87 of the 346 mucosa‒associated lymphoid tissue (MALT) lymphoma specimens (25%) were found to be positive for Cps. Ninety‐four of the 104 Cps‒positive OAL specimens (90%) came from 3 of the 11 studies. There was wide variation noted between geographic regions and even between studies from the same geographic region with regard to the rate of Cps positivity. The 4 studies concerning the efficacy of antibiotics for OAL were from Italy, Austria, Taiwan, and the U.S. and included 42 patients. Twenty patients (48%) achieved some response (complete response in 8 patients, partial response in 8 patients, and minimal response in 4 patients). Twenty patients also had stable disease, and 2 patients progressed during antibiotic therapy. Objective documentation of response (radiographs or clinical slit‐lamp photographs) was available for only 3 of the 42 patients. Seven additional patients developed disease recurrence after their initial response or stable disease after antibiotic therapy; 6 of these cases of disease recurrence occurred during the first 12 months of follow‒up.

CONCLUSIONS.

The findings of the current study suggest a striking variability in the association between Cps and OAL across geographic regions and even between studies from the same geographic regions. The overall rate of Cps positivity in our meta‒analysis (23%) was much lower than that reported in the original report. The current study findings also suggest that antibiotics have variable efficacy against OAL. Future prospective trials with standard objective response criteria and a longer follow‒up period would be necessary to evaluate the role of antibiotics in the treatment of OAL further. Cancer 2007; 110:809–15. © 2007 American Cancer Society.
Epidemiology of multiple myeloma in Taiwan
Authors: Huang Shang‐Yi , Yao Ming , Tang Jih‐Luh , Lee Wen‐Chung , Tsay Woei , Cheng Ann‐Li , Wang Chiu‐Hwa , Chen Yao‐Chang , Shen Ming‐Ching , Tien Hwei‐Fang
Published: June 2007

BACKGROUND.

The incidence of multiple myeloma (MM) is lower in Asia than in western countries. However, no data are available on descriptive epidemiology of MM in Chinese.

METHODS.

From 1979 to 2003, 3602 MM patients were registered in the Taiwan National Cancer Registry. The annual incidence and mortality were calculated and age‐standardized to the world standard population in the year 2000. Age‐period‐cohort effects on incidence were analyzed. The salient clinical data of 526 MM patients in a single institute were also investigated.

RESULTS.

From 1979 to 2003, the average age‐adjusted incidence per 100,000 population was 0.75. The incidence increased with age to a peak of 5.2 in those aged 75–79 years. In addition to age, remarkable period and birth cohort effects were found to contribute to increased incidence of MM. The age‐adjusted mortality also increased, which accounted for an average of 0.59 per 100,000 deaths; however, the fatality rate was steady at 80%. Clinical and laboratory characteristics and treatment outcomes of the 526 MM patients were similar to those reported elsewhere. Remarkably, extramedullary myeloma (extra‐MM) at diagnosis was more common in patients younger than 55 years of age than in others (43% vs 13%, P < .001).

CONCLUSIONS.

Incidence of MM in Taiwan has dramatically increased in recent years and is associated with a birth‐cohort effect. There are no apparent differences in treatment outcome between MM patients in Taiwan and in other countries. However, prevalence of extra‐MM is higher in patients younger than 55 years of age. Cancer 2007; 110:896–905. © 2007 American Cancer Society.
Increasing stereotypy in adult zebra finch song correlates with a declining rate of adult neurogenesis
Authors: Pytte Carolyn L. , Gerson Miles , Miller Janet , Kirn John R.
Published: June 2007

Adult neurogenesis is often correlated with learning new tasks, suggesting that a function of incorporating new neurons is to permit new memory formation. However, in the zebra finch, neurons are added to the song motor pathway throughout life, long after the initial song motor pattern is acquired by about 3 months of age. To explore this paradox, we examined the relationship between adult song structure and neuron addition using sensitive measures of song acoustic structure. We report that between 4 and 15 months of age there was an increase in the stereotypy of fine‐grained spectral and temporal features of syllable acoustic structure. These results indicate that the zebra finch continues to refine motor output, perhaps by practice, over a protracted period beyond the time when song is first learned. Over the same age range, there was a decrease in the addition of new neurons to HVC, a region necessary for song production, but not to Area X or the hippocampus, regions not essential for singing. We propose that age‐related changes in the stereotypy of syllable acoustic structure and HVC neuron addition are functionally related. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007.
A Novel Functionalized Single‐Wall Carbon Nanotube Modified Electrode and Its Application in Determination of Dopamine and Uric Acid in the Presence of High Concentrations of Ascorbic Acid
Authors: Zhang Yuzhong , Pan Yan , Su Shao , Zhang Liping , Li Shuping , Shao Mingwang
Published: June 2007

Multilayer films of negatively charged single‐wall carbon nanotubes (SWCNTs) and positively charged cetylpyridinium bromide (CPB) have been deposited on a glassy carbon electrode (GCE) using layer‐by‐layer (LBL) technique. The assembled multilayer films have been investigated by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and quartz crystal microbalance (QCM) measurements. The voltammetric signal of dopamine (DA), uric acid (UA), and ascorbic acid (AA) could be observed well‐separated with the assembled SWCNTs/CPB multilayer films in pH 7.0 PBS. The oxidation peak potentials of DA, UA, and AA are centered at about 169 mV, 292 mV and −10 mV on differential pulse voltammograms (DPVs), respectively. The peak‐to‐peak potential separation was 123 mV, 179 mV, and 302 mV for DA‐UA, DA‐AA, and UA‐AA in DPVs, respectively. This permits the simultaneous detection of DA and UA in the presence of AA.
Properties of Dendrimer‐Encapsulated Pt Nanoparticles Doped Polypyrrole Composite Films and Their Electrocatalytic Activity for Glucose Oxidation
Authors: Tang Longhua , Zhu Yihua , Xu Lihuan , Yang Xiaoling , Li Chunzhong
Published: June 2007

A type of novel electroanalytical sensing nanobiocomposite material was prepared by electropolymerization of pyrrole containing poly(amidoamine) dendrimers‐encapsulated platinum nanoparticles (Pt‐PAMAM), and glucose oxidase (GOx). The Pt nanoparticles encapsulated in PAMAM are nearly monodisperse with an average diameter of 3 nm, and they provide electrical conductivity. Polypyrrole acts as a polymer backbone to give stable and homogeneous cast thin films, and it also defines the electrical conductivity. Both Polypyrrole and PAMAM can provide a favorable microenvironment to keep the bioactivity of enzymes such as glucose oxidase. The homogeneity of GOx/Pt‐PAMAM‐PPy nanobiocomposite films was characterized by atomic force microscopy (AFM). Amperometric biosensors fabricated with these materials were characterized electrochemically using cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and amperometric measurements in the presence of hydrogen peroxide or glucose. All those show the resultant biosensor sensitivity was strongly enhanced within the nanobiocomposite film. The optimized glucose biosensor displayed a sensitivity of 164 μA mM−1 cm−1, a linear range of 0.2 to 600 μM, a detection limit of 10 nM, and a response time of <3 s.
Gene expression analysis of multiple gastrointestinal regions reveals activation of common cell regulatory pathways following cytotoxic chemotherapy
Authors: Bowen Joanne M. , Gibson Rachel J. , Tsykin Anna , Stringer Andrea M. , Logan Richard M. , Keefe Dorothy M.K.
Published: June 2007

Gastrointestinal mucositis involves many changes at the gene level, affecting epithelial/subepithelial interactions and leading to overt damage. The regional specificity and time course of these changes, and how they relate to subsequent mucositis development however remain unknown. The aim of this study was to determine the early time course of gene expression changes along the gastrointestinal tract of the DA rat following chemotherapy. Female DA rats were treated with a single dose of 200 mg/kg irinotecan to induce mucositis, and were killed at short intervals following treatment. Small sections of stomach, jejunum and colon were harvested for analysis of genetic profiles. RNA was hybridised to high density Affymetrix oligonucleotide microarrays. Data analysis was carried out with software package, TimeCourse, freely available through Bioconductor. As early as 1 hr following chemotherapy, expression of hundreds of genes was altered, including those for transcription factors, stress response proteins and protein turnover. These genes are involved in cell proliferation, differentiation and apoptosis along with other cellular processes. At early time points, there was a significant response involving the mitogen‐activated protein kinase pathway, cell cycle regulation and cytokine receptor signalling. At later time points, changes to the complement cascade became prominent. We have shown that changes in gene expression following chemotherapy occur by 1 hr, and persist for at least 72 hr after treatment. Many of these changes are highly likely to be specifically related to the subsequent development of gastrointestinal mucositis. © 2007 Wiley‐Liss, Inc.
Identification of Fn14/TWEAK receptor as a potential therapeutic target in esophageal adenocarcinoma
Authors: Watts George S. , Tran Nhan L. , Berens Michael E. , Bhattacharyya Achyut K. , Nelson Mark A. , Montgomery Elizabeth A. , Sampliner Richard E.
Published: June 2007

Given the poor survival rate and efficacy of current therapy for esophageal adenocarcinoma (EAC), there is a need to identify and develop new therapeutic targets for treatment. Microarray analysis (Affymetrix U133A GeneChips, Robust Multi‐Chip Analysis) was used to expression profile 11 normal squamous and 18 Barrett's esophagus biopsies, 7 surgically resected EACs and 3 EAC cell lines. Two hundred transcripts representing potential therapeutic targets were identified using the following criteria: significant overexpression in EAC by analysis of variance (p = 0.05, Benjamini Hochberg false discovery rate); 3‐fold increase in EAC relative to normal and Barrett's esophagus and expression in at least 2 of the 3 EAC cell lines. From the list of potential targets we selected TNFRSF12A/Fn14/TWEAK receptor, a tumor necrosis factor super‐family receptor, for further validation based on its reported role in tumor cell survival and potential as a target for therapy. Fn14 protein expression was confirmed in SEG‐1 and BIC‐1 cell lines, but Fn14 was not found to affect tumor cell survival after exposure to chemotherapeutics as expected. Instead, a novel role in EAC was discovered in transwell assays, in which modulating Fn14 expression affected tumor cell invasion. Fn14's potential as a therapeutic target was further supported by immunohistochemistry on a tissue microarray of patient samples that showed that Fn14 protein expression increased with disease progression in EAC. © 2007 Wiley‐Liss, Inc.
Patients with previous cancer should not be excluded in international comparative cancer survival studies
Authors: Brenner Hermann , Hakulinen Timo
Published: June 2007

In international comparisons or time trend analyses of cancer survival, it is common practice to restrict analyses to patients with a first cancer, i.e., to exclude patients with previous cancer diagnoses. However, the proportion of cancer patients with known previous cancer depends on the time cancer registries have been running, which results in varying proportions of excluded patients across registries. If prognosis of patients with second cancers differs from prognosis of patients with first cancers, varying exclusions may bias survival comparisons. We empirically evaluate the dependence of proportions of patients recorded as having a first cancer on time since initiation of cancer registration and the impact of excluding patients with known previous cancer on cancer survival estimates using the data of the nationwide Finnish Cancer Registry. Among 20 common cancer sites investigated, the proportion of “first cancers” varied between 97.4 and 99.7% in 1953–1957, the first 5‐years of cancer registration, and decreased continuously to levels between 83.9 and 92.7% in 1993–1997. Excluding patients with a previous cancer diagnosis had little impact on estimates of survival of cancer patients diagnosed in 1953–1957, but increased 5‐year relative survival estimates among patients diagnosed in 1993–1997 for each of the 20 cancers. The extent of the increase varied by cancer site and age. The increase ranged up to 2.9% points for crude and up to 1.7% points for age adjusted 5‐year relative survival. These results caution against exclusion of patients with previous cancer diagnosis in comparative analyses of cancer survival. © 2007 Wiley‐Liss, Inc.
Comparative in vitro study of the cell proliferation of ovine and human osteoblast‐like cells on conventionally and rapid prototyping produced scaffolds tailored for application as potential bone replacement material
Authors: Wagner M. , Kiapur N. , Wiedmann‐Al‐Ahmad M. , Hübner U. , Al‐Ahmad A. , Schön R. , Schmelzeisen R. , Mülhaupt R. , Gellrich N.‐C.
Published: June 2007

Reconstruction of bone defects in the field of craniomaxillofacial surgery is a relevant problem. In regenerative medicine, autologous bone is not available sufficiently. The full replacement of autologous bone grafts is required. A promising research field is the bone engineering. Especially the application of rapid prototyping (RP) enables new perspectives concerning the scaffold design. The aim of the study was to compare scaffolds produced by RP‐technology (native and plasma‐coated PLGA‐scaffolds) with conventionally produced scaffolds (agar plates with hydroxyapatite and hyaluronic acid coated agar plates with hydroxyapatite) relating to proliferation, adhesion, and morphology of osteoblasts to get knowledge about the application potential of such 3D‐manufactured matrices for bone engineering. TissueFoil E served as reference. To compare the scaffolds, 12 ovine and 12 human osteoblast‐like cell cultures of the skull were used. Results were obtained by EZ4U, scanning electron microscopy, and light microscopy. The highest cell proliferation rate of human osteoblast‐like cells was measured on TissueFoil E followed by plasma‐coated PLGA‐scaffolds and uncoated PLGA‐scaffolds, whereas of ovine osteoblast‐like cells on plasma‐coated PLGA‐scaffolds followed by TissueFoil E and uncoated PLGA‐scaffolds. Human and ovine osteoblast‐like cells on coated and uncoated agar plates had significant lower proliferation rates compared with TissueFoil E and PLGA‐scaffolds. These results showed the potential of RP in the field of bone engineering. Mechanical properties of such scaffolds and in vivo studies should be investigated to examine if the scaffolds hold up the pressure it will undergo long enough to allow regrowth of bone and to examine the revascularization. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Study on the heat resistant property of Ag/4A antibacterial agent
Authors: Bingshe Xu , Wensheng Hou , Shuhua Wang , Liqiao Wei , Husheng Jia , Xuguang Liu
Published: June 2007

The heat resistant property of silver‐loading zeolite 4A antibacterial agent (SLZ) was investigated by heat treatment methodology. The morphological and structural changes of the specimens were characterized by using differential thermal analyzer (TG‐DTA), scanning electron microscopy, and X‐ray diffraction techniques. The particle size of the specimens was measured by Malvern instruments zetasizer systems, and silver content of specimens was determined by inductively coupled plasma spectrometer. Escherichia coli (E. coli) was chosen as indicators of fecal contamination to evaluate the antibacterial effect of the specimens by minimum inhibitory concentration method. The service life of the specimens was also tested. The experimental results indicated that as heat‐treatment temperature increases, the particle size increases, more aggregating occurs, silver content decreases, the color of SLZ gradually changes from white to brown, and the antibacterial ability falls. The release rate of Ag+ cation from SLZ became slow after heat treatment at 400, 450, and 500°C, thus resulting in prolonged service life of SLZ. When the heat‐treatment temperature approached 800°C, the collapse of SLZ structure occurred, and the crystals of SiO2 and Al2O3 were formed after recrystallization. Consequently, the heat resistant temperature of SLZ can be as high as 500°C. SLZ could be used in antibacterial plastics, antibacterial fibers, or biomedical materials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008