bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictive input parameters for enteric virus presence at the inlet of a potable water supply
Authors: Freitas S.J. , Brion G.M. , Black L. , Coakley T.
Published: August 2006

Kentucky river water samples were collected at the input of a potable water supply weekly, for a period of two years. Eighteen parameters were analysed and/or recorded for each weekly observation. The variables were of a physical, chemical and biological nature. Enteric virus presence was detected by cell culture analysis from ∼200 L samples of river water. A database of 108 observations was assembled. Of these only 100 complete observations were used for the modelling analysis. Model input parameters were selected solely based on their statistical significance in forward, backward and stepwise selection procedures. Multivariate logistic regression (MLR) was used to determine the relative significance of the input parameters for predicting the presence or absence of enteric virus. The final, best-fit MLR model that used log-transformed values for enterococci, the AC/TC ratio, faecal coliforms (FC) and temperature demonstrated 82.5 and 81.4% sensitivity and specificity, respectively.
Removal of cyanobacteria, cyanotoxins, heterotrophic bacteria and endotoxins at an operating surface water treatment plant
Authors: Rapala J. , Niemelä M. , Berg K.A. , Lepistö L. , Lahti K.
Published: August 2006

The removal of cyanobacteria, hepatotoxins produced by them (microcystins), phytoplankton, heterotrophic bacteria and endotoxins were monitored at a surface water treatment plant with coagulation, clarification, sand filtration, ozonation, slow sand filtration and chlorination as the treatment process. Coagulation–sand filtration reduced microcystins by 1.2–2.4, and endotoxins by 0.72–2.0 log10 units. Ozonation effectively removed the residual microcystins. The treatment process reduced phytoplankton biomass by 2.2–4.6 and heterotrophic bacteria by 2.0–5.0 log10 units. In treated water, the concentration of microcystins never exceeded the WHO guide value (1 μg/L), but picoplankton and monad cells were often detected in high numbers. The heterotrophic bacterial isolates from the treated waters belonged to genera Sphingomonas, Pseudomonas, Bacillus, Herbaspirillum and Bosea.
Coliforms and other microbial indicators occurrence in water and biofilm in full-scale distribution systems
Authors: Batté M. , Féliers C. , Servais P. , Gauthier V. , Joret J.-C. , Block J.-C.
Published: August 2006

Biofilm and microbial water quality were studied in four middle size full-scale distribution systems (DS) in France serving 5,000–30,000 inhabitants (maximum residence time 23–160 h) through three sampling campaigns over 1 year. Three of these DSs were chosen because of a quite high occurrence of bacterial indicators (i.e. total coliforms), the last DS was considered as a reference. Biofilm was studied on cast iron coupons incubated for more than 1 month in devices continuously fed with water from the DS in conditions imitating those met in DS. The devices were located at different points (4–6) along each DS. The abundance of bacteria in biofilm was estimated by heterotrophic plate counts (HPC) after detachment of the biofilm from the support by sonication. Microbiological water quality was estimated in parallel; analysis of total coliforms, E. coli, enterococci and anaerobic sulphide-reducing bacteria spores (ASRB spores) was carried out in biofilm and water. Over the period of the study, 171 water samples and 57 biofilm samples were collected. Over these 171 waters, 19 (11%) were positive for at least one of the measured indicators while two biofilm samples were positive (3.5%). Significant differences were observed in the levels of contamination between the DSs. High residence time in the DS, low disinfectant residual and high temperature increased the risk of indicator occurrence in the water phase. Due to the low number of biofilm samples positive for bacterial indicators, the data collected in the present study did not allow observation of a direct association between biofilm and water contaminations, even if the occurrence of indicators in water appeared on DSs with the highest density of biofilm (HPC).
Microbiological quality of reclaimed water used for golf courses' irrigation
Authors: Alonso M.C. , Dionisio L.P.C. , Bosch A. , Pereira de Moura B.S. , Garcia-Rosado E. , Borrego J.J.
Published: August 2006

Microbial quality of reclaimed water used for irrigation in two golf courses located in the southern Iberian Peninsula (Spain and Portugal) was evaluated. Bacterial indicators for faecal pollution (total and faecal coliforms, Escherichia coli and enterococci) were tested by membrane filtration using appropriate selective media. In addition, somatic E. coli bacteriophages, enteric viruses (entero-, hepatitis A and rota-) and Legionella pneumophila were also analysed. The results obtained showed that all wastewater treatment processes reduced adequately the number of indicator microorganisms although a significant correlation between pathogenic and indicator microorganisms tested was not found. L. pneumophila was detected by PCR but not confirmed by culture. Survival experiments of pathogenic microorganisms in aerosols and irrigated turf are conducted to determine the health hazards for the golf practice and to propose a microbial standard for wastewater used for irrigation of golf courses.
Quantification and genotyping of Cryptosporidium spp. in river water by quenching probe PCR and denaturing gradient gel electrophoresis
Authors: Masago Y. , Oguma K. , Katayama H. , Ohgaki S.
Published: August 2006

A new detection method was developed for the simultaneous quantification and genotyping of Cryptosporidium spp. in river water. Several modifications made to the US EPA Method 1623 enabled high and stable recovery of Cryptosporidium from 40 L of river water (geometric mean =35%, standard deviation =8.7%). Quenching probe PCR (QProbe PCR) was used to quantify the 18S rRNA gene of Cryptosporidium spp. This method could successfully detect single oocysts in a sample, and the lower quantitation limit was as low as 2.5 oocysts/sample. In addition, denaturing gradient gel electrophoresis (DGGE) followed by DNA sequencing was used to identify the genotypes. These methods were applied to detect Cryptosporidium spp. in the Koyama River, Japan. The positive ratio was 69% (11/16) with the maximum concentration of 59 oocysts/100 L. Seven genotypes including two novel ones were identified. These results showed that this detection method could provide valuable information on Cryptosporidium in river water, both in the concentration and in the genotypes, which is essential for the precise assessment of waterborne risk to human health.
Detection and occurrence of antimicrobially resistant E. coli in groundwater on or near swine farms in eastern North Carolina
Authors: Anderson M.E. , Sobsey M.D.
Published: August 2006

The use of antibiotics for growth promotion and disease treatment by the commercial swine industry has led to high proportions of multiple antibiotic-resistant enteric bacteria being shed by these animals and concerns about the environmental spread of these bacteria. A study was conducted to quantify the extent of release of antibiotic-resistant E. coli from swine farms into groundwater. Four study sites, two swine farms and two reference sites (crop farms), with known groundwater flow paths were screened for E. coli four times over the course of one and a half years. A total of 100 biochemically-confirmed E. coli were collected from the four sites. There were statistically significantly higher E. coli levels at the two swine farm sites than at the reference sites. The bacterial isolates were tested for antibiotic resistance using a panel of 17 drugs that are typical of human and veterinary use. There were 19 and 71 E. coli isolates from swine farms #1 and #2, respectively, with most (68%) being resistant to 1–6 antimicrobials. Only one E. coli isolate from each of the reference sites showed antimicrobial resistance traits. The results of this study demonstrate that antibiotic-resistant E. coli strains are present in groundwaters of swine farms with a typical lagoon and land application system for waste management.
Microbial risk and removal—a utility perspective
Authors: Stanger M. , Agutter P.A. , Lake R.C. , Ashbolt N.J. , Roser D.J.
Published: August 2006

In this paper the results of a sampling programme, undertaken as part of the EU MicroRisk project, are described. This project was undertaken to ascertain the occurrence of pathogens and indicators in the River Thames and their subsequent removal through a treatment works. Appropriate physico-chemical surrogates, as determined by statistical correlation are proposed for the microorganisms identified in the raw water. This study shows that under normal raw water conditions the treatment works is able to remove microbial contamination with a significant margin of safety.
Simultaneously Improving Strength and Ductility of Magnesium using Nano‐size SiC Particulates and Microwaves
Authors: E Wong W. L. , Gupta M.
Published: August 2006

Magnesium composites containing nano‐size SiC particulates were synthesized using powder metallurgy technique incorporating microwave assisted rapid sintering. Microstructural characterization revealed minimal porosity and the presence of a continuous network of nano‐size SiC particulates decorating the particle boundaries of the metal matrix. Mechanical characterization revealed that the addition of nano‐size SiC particulates lead to a simultaneous increase in microhardness, 0.2% yield strength, ultimate tensile strength and ductility of the matrix.
Investigation on Forming Defects During Thixo‐forging of Aluminum Alloy AlSi7Mg
Authors: Wang K. K. , Kopp R. , Hirt G.
Published: August 2006

The appearance of pores and segregation between solid/liquid phases during semi‐solid forming has been a long‐term challenge for the large scale utilization of semi‐solid forming in industry. Both phenomena can be influenced by velocity, temperature and pressure. In this study a flat flange and an angled flange were used in investigating the metal flow behavior during thixo‐forging of aluminum parts. Evaluations of the thixo‐forged parts were performed with x‐ray inspection, microstructure and segregation analysis. The experimental results show significant tendencies between the types of the flange and the forming defects of pores and segregationThe results of numerical simulations showed that the hydrostatic stress was the main reason for the appearance of pores. The x‐ray inspections revealed that the appearance of pores and segregation during thixo‐forging could be avoided or alleviated by optimized die design.
Microstructure of Porous TiO2 Coating on Pure Ti by Micro‐arc Oxidation
Authors: Chen C. , Dong Q. , Yu H. , Wang X. , Wang D.
Published: August 2006

Oxide coatings were deposited on the substrate of pure titanium by a technology called micro‐arc oxidation. The phase content, surface and cross‐section micrographs, element distributions of the coating were observed and analyzed by XRD, SEM and EDS, respectively. A transitional zone with a thickness of 3–4 μm was observed on the interface between the coating and substrate, and the coating has an high hardness of 567 HV0.025. It is believed that the micro‐arc oxidation technique will have a great potential for the surface activation for Ti‐implants.
Three Dimensional Characterization of Unmodified and Sr‐Modified Al‐Si Eutectics by FIB and FIB EDX Tomography
Authors: Lasagni F. , Lasagni A. , Holzapfel C. , Mücklich F. , Degischer H. P.
Published: August 2006

This article provides a study of the three‐dimensional morphology of different eutectic architectures of unmodified and Sr‐modified AlSi‐alloys. These 3D‐structures were reconstructed by means of a new Focused Ion Beam – Energy Dispersive Spectroscopy (FIB‐EDX) method, consisting in 2D sectioning and subsequent computer imaging. The Si‐structure and its interconnectivity are investigated, as well as the morphological changes induced by the addition of Sr.
Crystallization Kinetics of the (Zr58Ni13.6Cu18Al10.4)Nb1 Bulk Metallic Glass
Authors: Qiao D. , Fan C. , Liaw P. K. , Choo H.
Published: August 2006

The differential thermal analysis (DTA) curve of the (Zr58Ni13.6Cu18Al10.4)Nb1 bulk metallic glass (BMG) shows that there are two exothermic crystallization peaks and two endothermic melting peaks. The BMG has been completely crystallized in the first crystallization peak. X‐ray shows that the quenched BMG only includes the glass single phase. The BMG heated to 823 K (between the first and the second crystallization peak) has the precipitation of the cubic NiZr2. The BMG heated to 1003 K (after the second crystallization peak) has the cubic NiZr2, bct NiZr2, and bct CuZr2. HRTEM shows that there are some nano‐crystalline phases for the quenched BMG.
Long Fibre Reinforced NiAl: High Temperature Material for Turbine Blades
Authors: Rosefort M. , Dahmen C. , Bührig‐Polaczek A. , Hu W. , Zhong H. C. Y. , Gottstein G. , Hajas D. , Schneider J. M.
Published: August 2006

For environmental reasons an increase of the efficiencies of power stations is needed and further improvements of materials are essential. Today combined gas and steam turbine power stations obtain overall efficiencies of 58 %. Temperatures of approximately 1230 °C in gas turbines exceed the load limits of the commonly used materials. For efficiency increase turbine inlet temperatures must be increased up to 1350 °C (ISO) in the gas turbine.
Processing, Microstructure and Mechanical Properties of in Situ Al‐based Metal Matrix Composite Reinforced with 22 wt%WAl12 Particles
Authors: Cai S. G. , Ma X. F. , Tang H. G. , Zhao W. , Zhu C. J. , Yan J. M. , Qiao Z. H. , Zhao B.
Published: August 2006

The MAed Al‐15wt%W14Al86 sintered at 650 °C for 30min. In situ formed WAl12 intermetallic reinforcements with size μm were dispersed continuously in the Al matrix. Its fracture surface was of the cleavage type. The observation demonstrated the effectiveness of the WAl12 intermetallic phase reinforcement in this MMC.
Generation Mechanism and in situ Growth Behavior of α‐Iron Nanocrystals by Electron Beam Induced Deposition
Authors: Zhang W. , Shimojo M. , Takeguchi M. , Che R.‐C. , Furuya K.
Published: August 2006

Amorphous iron‐containing deposits were formed on carbon films by electron beam induced deposition with a precursor of iron pentacarbonyl and alpha‐Fe nanocrystals were grown around the target tip deposits when the electron beam irradiation time was longer than 1000 s.
Stress Corrosion Cracking and Hydrogen Diffusion in Magnesium
Authors: Atrens A. , Winzer N. , Song G. , Dietzel W. , Blawert C.
Published: August 2006

Evaluation of recent data for hydrogen (H) diffusion in magnesium (Mg) yielded a new equation for the diffusion coefficient of H in Mg. This indicates that there can be significant H transport ahead of a stress corrosion crack in Mg at ambient temperature and that H may be involved in the mechanism of stress corrosion cracking in Mg.
The Exploitation of Superplasticity in the Successful Foaming of Ceramics after Sintering
Authors: Kishimoto A. , Higashiwada T. , Asaoka H. , Hayashi H.
Published: August 2006

A model ceramic foam was produced by expanding the sintered dense shell of refractory 3 mol% yttria‐stabilized zirconia, utilizing its superplastic deformation. The conventional production of porous ceramics by the sintering of a foamed precursor results in either insufficient sintering if porosity is to be maintained, or sacrifices porosity in order to improve inter‐grain bonding. In the new model ceramics, the foaming procedure is carried out following sintering and there is no reduction in inter‐grain bonding; instead, a high level of porosity is attained along with high structural reliability.
Ceramic Foams for Al‐Recycling
Authors: Luyten J. , Vandermeulen W. , De Schutter F. , Simensen C. , Ryckeboer M.
Published: August 2006

The recycling of Al scrap requires an efficient purification step. In this investigation a filter technique is used to remove intermetallic compounds containing Fe, Mn and Si out of the molten Al. The paper describes the synthesis of the filters, the construction of the filter installation, and the results of the different filter tests.
Cover Picture: Three Dimensional Characterization of Unmodified and Sr‐Modified Al‐Si Eutectics by FIB and FIB EDX Tomography (Adv. Eng. Mater. 8/2006)
Authors: Lasagni F. , Lasagni A. , Holzapfel C. , Mücklich F. , Degischer H. P.
Published: August 2006

The cover shows the 3D‐morphology of the eutectic Si phase in an unmodified AlSi12‐alloy. These 3D‐structures were reconstructed by means of a new Focused Ion Beam Energy Dispersive Spectroscopy (FIB‐EDX) method. More about the study of the three‐dimensional morphology of different eutectic architectures of unmodified and Sr‐modified AlSi‐alloys can be found in the article by F. Lasagni et al. on page 719.
Prediction of two‐phase flow distribution in parallel pipes using stability analysis
Authors: Pustylnik L. , Barnea D. , Taitel Y.
Published: August 2006

Two‐phase gas liquid flow in pipes is a complex process. One of the problems that is hardly understood is how the two phases are distributed among two or more parallel lines with a common inlet manifold. Steady‐state analysis yields multiple steady‐state solutions. Linear and nonlinear (simulation) stability analyses are performed in order to determine the actual distribution of the flow that will take place in a real system. The analysis shows that when there are four parallel pipes, for example, the two‐phase flow mixture from the common inlet manifold can choose to flow in one, two, three, or in all four pipes, depending on the flow rates of the liquid, and the gas and on the pipes inclination. For low‐flow rates of gas and liquid, the flow tends to take place only in one line, while stagnant liquid columns are present in the other three pipes. As the flow rate increases the flow will take place in 2, 3 and finally in 4 pipes. Experimental data confirm the analysis although matching is only approximate. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Generalized mass‐transfer correction factor for nanofiltration and reverse osmosis
Authors: Geraldes Vítor , Afonso Maria Diná
Published: August 2006

The assessment of the concentration polarization in pressure‐driven membrane modules is fundamental for their design and optimization. To account for the suction effect in nanofiltration (NF)/reverse osmosis (RO) membrane modules, a correction factor for conventional mass‐transfer coefficients at vanishing mass‐transfer rates was obtained through computational fluid dynamics (CFD) simulations of a symmetrical NF/RO rectangular channel with fully developed laminar flow, for a wide range of operating conditions. The correction factor is defined as Ξ = Sh/Sh0, where Sh is the Sherwood number with suction and Sh0 is the Sherwood number for impermeable walls and low mass‐transfer rates. For the range of dimensionless numbers assigned in the simulations, it was found by fitting of CFD data that Ξ depends only on ϕ = Pe/Sh0, through the correlation Ξ = ϕ + (1 + 0.26ϕ1.4)−1.7, where Pe is the permeation Peclet number. This correlation can be used to predict the average concentration polarization index, Γ = R/(Ξ/ϕ − R), where R is the intrinsic rejection, with an average relative error of 3.2%. The correlation obtained appears to be suitable to determine mass‐transfer coefficients at high mass‐transfer rates, independently of the membrane module geometry and the flow regime. Moreover, unlike the correction factor correlations available in the literature, the generalized correlation accurately predicts the concentration polarization index for ϕ < 20. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Evaluation of QT dispersion in β thalassaemia major patients
Authors: Ulger Zulal , Aydinok Yesim , Levent Erturk , Gurses Dolunay , Ozyurek A. Ruhi
Published: August 2006

Cardiac complications are considered to be the primary cause of death in patients with β thalassaemia major. QT dispersion is a marker variability of ventricular repolarization and is elevated in various high risk groups of patients. This study was carried out in patients with β thalassaemia major to evaluate QT dispersion and to investigate the relationship between QT dispersion and body iron load. Sixty‐two β thalassaemia major patients were enrolled into the study. The average serum ferritin levels and liver iron concentration was assessed. For each patient, QT–QTc intervals and QT–QTc dispersions were calculated and V1S and V5R were measured. All the subjects underwent two‐dimensional M mode echocardiogram and Doppler study. LVMI was found higher in thalassaemia major patients compared to control group. β thalassaemia major patients showed significantly higher mean QT, QTc, QTd, and QTcd values compared to the control group. The mean V5R and V1S amplitudes were also higher in β thalassaemia major patients. There was a positive correlation between LVMI and QTc, QTd and QTcd. However, there was no significant correlation between QT dispersion and serum ferritin and liver iron concentration. Prospective longitudinal studies are needed to assess the prognostic significance of these findings. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.
First day dynamic changes in antithrombin III activity after supplementation have a predictive value in critically ill patients
Authors: Gando Satoshi , Sawamura Atsushi , Hayakawa Mineji , Hoshino Hirokatsu , Kubota Nobuhiko , Oshiro Akiko
Published: August 2006

To evaluate the changes in the antithrombin III (antithrombin) values after initial supplementation to predict outcome in critically ill patients, we conducted a retrospective study. All consecutive patients admitted to the intensive care unit (ICU) and treated with antithrombin were enrolled in the study. Initial doses of 1,500 IU or 30 IU/kg antithrombin concentrates were administered over an hour. The clinical backgrounds of the patients were collected from computer‐based records. Serial data of antithrombin were collected from the first day of administration (Day 0) to days 1–4. The patients were subdivided into two groups based on whether they demonstrated an increased antithrombin activity of more than 60% on the first day after the initial supplementation (responders) or not (nonresponders). Four hundred thirty‐five patients were enrolled in the present study. Two hundred eighty‐eight patients could achieve an antithrombin activity of more than 60%. The outcome was significantly different between the two groups. A logistic regression analysis revealed the day 1 antithrombin level and an initial increase of less than 60% after supplementation to be independently associated with ICU mortality. We also found a significant increase in the platelet counts and fibrinogen levels, and a decrease in the disseminated intravascular coagulation (DIC) scores for the responders. In conclusion, our findings demonstrated the first‐day dynamic change in antithrombin activity, and not the basal level, to be able to predict critically ill patient death. This dynamic change was associated with an improvement in the platelet counts, fibrinogen levels, and the DIC score. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.
Role of intra‐arterial steroid administration in the management of steroid‐refractory acute gastrointestinal graft‐versus‐host disease
Authors: Tfayli Arafat , Selby George , Maqbool Feroz , Bierbaum Walter , Hamadani Mehdi
Published: August 2006

We report here a case of severe steroid‐refractory gastrointestinal graft‐versus‐host disease treated with intra‐arterial administration of corticosteroids. A 53‐year‐old female with non‐Hodgkin's lymphoma received peripheral blood hematopoietic stem cell transplant from her HLA‐matched sibling. She developed grade II skin and grade IV gastrointestinal graft‐versus‐host disease with no hepatic involvement. Therapy with oral prednisone easily controlled her skin rash but she had profuse diarrhea that did not respond to high dose intravenous corticosteroids and denileukin diftitox. Infusion of methyl‐prednisolone into superior and inferior mesenteric arteries produced dramatic improvement of diarrhea, with complete resolution of gastrointestinal graft‐versus‐host disease. Am. J. Hematol., 2006, © 2006 Wiley‐Liss, Inc.
A versatile denaturing HPLC approach for human β‐globin gene mutation screening
Authors: Bournazos Stavros N. , Tserga Aggeliki , Patrinos George P. , Papadakis Manoussos N.
Published: August 2006

Hemoglobinopathies represent the most common genetic disorder worldwide, with a higher prevalence among populations with a history of malaria endemicity. More than 690 mutations in the human β‐globin gene are usually the cause of β‐type hemoglobinopathies. Here, we report a rapid and highly sensitive β‐globin gene mutation screening approach based on denaturing high‐performance liquid chromatography (DHPLC), which contrary to the previously described ones can be used in every HPLC apparatus. The sensitivity and specificity of the method were tested in 120 healthy Greek subjects and 25 β‐thalassemia heterozygotes and homozygotes, in which 11 different β‐globin sequence variations had been previously characterized by denaturing gradient gel electrophoresis. Using this method, we were able to rapidly identify the commonest β‐globin gene mutations, accounting for more than 90% of the mutant β‐globin alleles reported for the Hellenic population. Compared to classical mutation screening approaches, our DHPLC approach provides the means for rapid, highly sensitive, cost‐effective, and semi‐automated simultaneous mutational scanning of a large number of samples. Am. J. Hematol., 2006, © 2006 Wiley‐Liss, Inc.
Limb amputation in hemoglobin SC disease after application of ice and elevation
Authors: Saleem Sadia , Rice Lawrence
Published: August 2006

A 31‐year‐old man with hemoglobin SC disease was admitted with acute chest syndrome, treated with antibiotics and ventilator support. His restrained right wrist and hand became swollen and cool, thought due to infiltration of an intravenous line. The hand was elevated, ice packs applied around the clock, and prophylactic low molecular weight heparin given. The arm quickly turned gangrenous. In spite of attempted thrombectomy and red blood cell exchange transfusion, amputation was required. Cold, elevation, and measures that reduce blood flow are known precipitators of sickling and crises. Vasoocclusion of the extremities to the point of gangrene is rarely reported in sickle cell disorders, and this case highlights the dangers of measures limiting blood flow in such patients. Am. J. Hematol., 2006. © 2006 Wiley‐Liss, Inc.
Titelbild: Luminescent One‐Dimensional Nanoscale Materials with PtII⋅⋅⋅PtII Interactions (Angew. Chem. 34/2006)
Authors: Sun Yinghui , Ye Kaiqi , Zhang Hongyu , Zhang Junhu , Zhao Lan , Li Bao , Yang Guangdi , Yang Bai , Wang Yue , Lai Siu‐Wai , Che Chi‐Ming
Published: August 2006

Platin(II)‐Platin(II)‐Wechselwirkungen vermitteln und steuern die Bildung mikro‐ und nanoskaliger molekularer Drähte aus [Pt(CNtBu)2(CN)2]. Das Titelbild zeigt Modelle und Mikroskopiebilder dieser photolumineszierenden Strukturen. Y. Wang, C.‐M. Che et al. beschreiben in ihrer Zuschrift auf S. 5738 ff. die Bildung und die photophysikalischen Eigenschaften der molekularen Drähte. Die Photolumineszenzantworten können auf der Grundlage einer Röntgenstrukturanalyse verstanden werden.
Macrocyclization by Ring‐Closing Metathesis in the Total Synthesis of Natural Products: Reaction Conditions and Limitations
Authors: Gradillas Ana , Pérez‐Castells Javier
Published: August 2006

The construction of macrocycles by ring‐closing metathesis (RCM) is often used as the key step in the synthesis of natural products containing large rings. This reaction is attractive because of its high functional group compatibility and the possibility for further transformations. The finding of suitable reaction conditions is critical for the success of the synthesis. In this Minireview we summarize the efforts of many research groups to develop efficient RCM reactions on their way towards the total synthesis of natural macrocyclic products. Their findings should help in future synthesis to reduce the time‐consuming phase of the optimization of the reaction conditions.
Release of dithiocarbamates into artificial sweat from latex vulcanizates: Effects of the accelerator type and storage time
Authors: Abraham Elizabeth K. , Ramesh P. , Joseph R.
Published: August 2006

The release of commonly used dithiocarbamate accelerators, namely, zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), zinc dibenzyldithiocarbamate, zinc isobutyldithiocarbamate, and zinc diisononyldithiocarbamate, into artificial sweat from natural rubber latex vulcanizates was studied. The extent of release of ZDEC was much higher than that of ZDBC or other higher homologues, as indicated by high‐performance liquid chromatography analysis. The effect of the storage time on the extent of release of ZDEC into artificial sweat from vulcanizates prepared with various amounts of ZDEC was studied. The result showed that ZDEC migrated significantly to the surface of the vulcanizates upon storage, and the amount that migrated increased with an increase in the shelf time. Moreover, the amount of ZDEC that migrated increased with an increase in the amount of ZDEC added to the latex formulations. The rate of migration, as determined from the slopes of the migration curves, was dependent on the residual ZDEC content, which in turn depended on the initial level of ZDEC incorporated during latex compounding. The analysis of the migration data showed that the migration followed a Fickian behavior, and the diffusion coefficient of ZDEC was slightly dependent on the concentration. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2055–2061, 2006
Melt‐compounded butadiene rubber nanocomposites with improved mechanical properties and abrasion resistance
Authors: Kim Min‐Su , Kim Dong‐Woo , Ray Chowdhury Subhendu , Kim Gue‐Hyun
Published: August 2006

Hydrophobic polymers such as polyethylene and polypropylene are very difficult to use for preparing nanocomposites without a compatibilizer. However, in this study, polybutadiene rubber (BR; a hydrophobic polymer) nanocomposites were produced successfully without a compatibilizer with a melt‐compounding method. Transmission electron microscopy showed an intercalated and exfoliated clay morphology in the polymer matrix, which led to increased mechanical properties. The tensile and tear strengths of the BR/Cloisite 20A hybrids were 4.4 times and 2 times larger than that of BR, respectively. The rebound resilience, compression set, and abrasion resistance were also improved by the addition of organoclay. The abrasion resistance of BR/Cloisite 20A was approximately 2 times larger than that of BR. The cure time (t90), scorch time (t2), and their difference (t90 − t2) of the BR/organoclay hybrids were much reduced than those of BR. Thus, organoclays behaved as good fillers and effective accelerant agents for BR vulcanization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2062–2066, 2006
Melting and crystallization behaviors of isotactic polypropylene/acrylonitrile–butadiene rubber blends in the presence and absence of compatibilizers and fillers
Authors: Joseph Aju , George Snoopy , Joseph Kuruvilla , Thomas Sabu
Published: August 2006

The melting and crystallization behaviors of isotactic polypropylene (PP)/acrylonitrile–butadiene rubber (NBR) blends were investigated with differential scanning calorimetry. The samples were scanned at a heating rate of 20°C/min in a nitrogen atmosphere. The effects of blend ratio, compatibilizer, and filler addition on the melting and crystallization characteristics of the blends were analyzed. Analysis showed that blend ratio had a predominant effect on the values of onset of crystallization and crystallization temperature, although the heat of fusion (ΔHf), onset of melting, and melting temperature were unaffected. The presence of compatibilizer in the blend had an appreciable influence on the crystallization behavior. ΔHf, heat of crystallization, and percentage crystallinity of the compatibilized blends were higher than those of the uncompatibilized blends. Fillers had little impact on the melting behavior of the blends. The morphology of the blends were analyzed with scanning electron microscopy. Hot‐stage polarizing optical microscopy was used to study the spherulitic morphology of PP on the addition of NBR. The addition of a few percentage NBR significantly reduced the average spherulite size of PP in the blend followed by a marginal decrease. Blend ratio had a pronounced impact on the growth rate of PP spherulites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2067–2080, 2006
Optimization of the preparation of a poly(aspartic acid) superabsorbent resin with response surface methodology
Authors: Zhao Ying , Fang Li , Tan Tianwei
Published: August 2006

A poly(aspartic acid) superabsorbent resin was synthesized with polysuccinimide through chemical crosslinking with a crosslinking agent (diamine). The optimization of its preparation was investigated with response surface methodology. According to the Plackett–Burman design, the crosslinking temperature, drying temperature, and dissolving time of polysuccinimide had significant influences on the swelling ratio of the poly(aspartic acid) resin, which was the criterion for describing the water absorption capacity. Central composite design and response surface analysis were employed subsequently to further optimize the three aforementioned factors. A maximum swelling ratio greater than 500 g/g was attained; this was more than a 60% increase in comparison with previous results. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2616–2622, 2006
Atom transfer radical polymerization of styrene with 2‐(1‐bromoethyl)‐anthraquinone as an initiator
Authors: Zhao Kang , Zhu Xiulin , Cheng Zhenping , Wang Gang , Zhu Jian
Published: August 2006

2‐(1‐Bromoethyl)‐anthraquinone (BEAQ) was successfully used as an initiator in the atom transfer radical polymerization of styrene with CuBr/N,N,N′,N′,N″‐pentamethyldiethylenetriamine as the catalyst at 110°C. The polymerizations were well controlled with a linear increase in the molecular weights (Mn's) of the polymers with monomer conversion and relatively low polydispersities (1.1 < weight‐average molecular weight (Mw)/Mn < 1.5) throughout the poly merizations. The resultant polystyrene thus possessed one chromophore moiety (2‐ethyl‐anthraquinone) at the α end and one bromine atom at the ω end, both from the initiator BEAQ. The intensity of UV absorptions of the resultant polymers decreased with increasing molecular weights of the polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2081–2085, 2006
Synthesis of conducting water‐soluble polyaniline with iron(III) porphyrin
Authors: Nabid M. R. , Sedghi R. , Jamaat P. R. , Safari N. , Entezami A. A.
Published: August 2006

The porphyrin‐catalyzed, template‐guided polymerization of aniline was carried out in an aqueous buffer solution. Hydrogen peroxide and iron(III) tetrasulfonated tetraphenyl porphyrin catalyzed the polymerization of aniline in the presence of sulfonated polystyrene as a template. The polymerization was carried out at different pHs ranging from 1 to 5. Ultraviolet–visible spectroscopy indicated the formation of a conducting form of polyaniline. The extent of the polymerization increased with decreasing pH of the solution. The maximum absorbance of the polaron band at 750 nm was obtained at pH 2, but when the polymerization was performed with pH 4, this band shifted to a longer wavelength. These results confirmed that a longer chain length of polyaniline was obtained with pH 4. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2929–2934, 2006
Flame retardancy and nondripping properties of ammonium polyphosphate/poly(butylene succinate) composites enhanced by water crosslinking
Authors: Kuan Chen‐Feng , Kuan Hsu‐Chiang , Ma Chen‐Chi M. , Chen Chia‐Hsun
Published: August 2006

Ammonium polyphosphate (APP)/poly(butylene succinate) (PBS) composites were prepared with a unique water‐crosslinking technique to improve the flame retardancy and nondripping properties of the composites and to maintain the main structure of the composites during flame tests. The composites were treated with a coupling agent (tetraethoxysilane) and then were compounded in a twin‐screw extruder. The compound was moisture‐crosslinked. Fourier transform infrared spectra were used to monitor the water‐crosslinking reaction. The composites via the water‐crosslinking treatment exhibited improved mechanical properties because of the interfacial bonding between the APP and PBS matrix. Scanning electron microscopy of the fractured surfaces of the water‐crosslinked composites showed that the void size increased with increasing water‐crosslinking time. Composites with 15 wt % APP were classified as UL‐94 V‐2; however, the ones with only a 0.5‐h water‐crosslinking reaction were classified as UL‐94 V‐0. Thermal analyses of the water‐crosslinked composites indicated that the thermal degradation temperature of the composites increased with increasing water‐crosslinking time. Differential scanning calorimetry results revealed that the water‐crosslinking reaction could limit the crystallization rate of PBS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2935–2945, 2006
Nanocomposite alkyd coatings
Authors: Jiratumnukul Nantana , Pruthipaitoon Sirirat , Pitsaroup Tossaporn
Published: August 2006

Organophilic montmorillonite intercalants were prepared by a cation‐exchange process between Na+ ions of montmorillonite and ammonium salt of octadecylamine. Fourier transform infrared (FTIR) spectrometry and X‐ray diffraction analyses of the compounds were carried out. The layer spacings of both modified and unmodified montmorillonites were calculated with Bragg's law. FTIR and X‐ray profiles showed organophilic characteristics for the modified montmorillonite, the layer spacing of which increased by two orders of magnitude with respect to that of the unmodified montmorillonite. The prepared organoclay was incorporated into an alkyd‐based clear coating, and X‐ray profiles showed an exfoliated structure for the organoclay alkyd coating. The application of the prepared organoclay to alkyd‐based clear coatings showed a significant enhancement of the hardness and impact strength of the coating film compared with those of unmodified montmorillonite equally incorporated into the coating formulations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2639–2642, 2006
Synthesis and characterization of poly(ϵ‐caprolactone)–poly(L‐lactide) diblock copolymers with an organic amino calcium catalyst
Authors: Piao Longhai , Sun Jingru , Zhong Zhiyuan , Liang Qizhi , Chen Xuesi , Kim Jung‐Hyun , Jing Xiabin
Published: August 2006

The quasiliving characteristics of the ring‐opening polymerization of ϵ‐caprolactone (CL) catalyzed by an organic amino calcium were demonstrated. Taking advantage of this feature, we synthesized a series of poly(ϵ‐caprolactone) (PCL)–poly(L‐lactide) (PLA) diblock copolymers with the sequential addition of the monomers CL and L‐lactide. The block structure was confirmed by 1H‐NMR, 13C‐NMR, and gel permeation chromatography analysis. The crystalline structure of the copolymers was investigated by differential scanning calorimetry and wide‐angle X‐ray diffraction analysis. When the molecular weight of the PLA block was high enough, phase separation took place in the block copolymer to form PCL and PLA domains, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2654–2660, 2006
Effects of modified poly(methacrylic acid) copolymer on rheological properties of ceramic suspension and sintered ceramic strength
Authors: Wang Haihua , Shen Yiding , Fei Guiqiang , Li Ganghui , Zhang Yaping
Published: August 2006

Modified waterborne poly(methacrylic acid) (MPBMA) with hydrophilic and hydrophobic groups is prepared by reacting maleic anhydride/polyglycol, α‐olefine benzenesulfone, and methyl methacrylate. Using MPBMA as a ceramic dispersant, the effects of the MPBMA concentration on the rheological behavior of a ceramic suspension and the ceramic breaking strength are studied, and the reasons and its dispersing mechanism are analyzed. The results show that MPBMA can improve the suspension's rheological properties and enhance the ceramic strength. The optimum copolymer concentration is 0.20 wt % at pH 9–10. When adding 0.20 wt % MPBMA, the suspension's absolute ζ potential increases from 23.7 to 64.2 mV, and its zero shear viscosity decreases from 714.3 to 73.4 mPa s. At the same time, its thixotropy area reaches the minimum, and the suspension exhibits Newton flow behavior and good dispersivity. Compared with inorganic dispersant, the ceramic with added MPBMA has higher breaking strength, which is increased from 160 to 352 MPa. Scanning electron microscopy photographs show that the flocculate of particles is disintegrated and the particles scatter mutually. They also show that no aggregation phenomenon appears in the ceramic with MPBMA added and the pores distribute uniformly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2661–2667, 2006
Curing of mixtures of epoxy resins and 4‐methyl‐1,3‐dioxolan‐2‐one with several initiators
Authors: Cervellera Roser , Ramis Xavier , Salla Josep Maria , Mantecón Ana , Serra Angels
Published: August 2006

Diglycidyl ether of bisphenol A or 3,4‐epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate were mixed with different proportions of 4‐methyl‐1,3‐dioxolan‐2‐one and cured using lanthanide triflates as initiators. In order to compare the materials obtained, conventional initiators such as boron trifluoride complexes andN,N‐dimethylaminopyridine were also tested. The curing process was followed by differential scanning calorimetry (DSC) and Fourier transform IR in attenuated total reflectance mode. This technique proved that the carbonate accelerates the curing process because it helps to form the active initiating species, although it was not chemically incorporated into the network and remained entrapped in the material. The DSC kinetic study was also reported. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2086–2093, 2006
Retention properties of arsenate anions of water‐soluble polymers by a liquid‐phase polymer‐based retention technique
Authors: Rivas Bernabé L. , Aguirre María del Carmen , Pereira Eduardo
Published: August 2006

The retention properties of arsenic ions from an aqueous solution by water‐soluble cationic polymers and cationic–anionic copolymers were investigated. Poly[(3‐methacryloylamine)propyl]trimethylammonium chloride [P(ClMPTA)] and poly[(3‐methacryloylamine)propyl]trimethylammonium chloride–co–acrylic acid [P(ClMPTA‐co‐AA] were synthesized by radical polymerization. The copolymers were prepared with feed mole ratios of ClMPTA to AA of 1 : 1, 1 : 2, and 2 : 1. The copolymer compositions were evaluated by FTIR spectroscopy, TG‐DSC, and elemental analysis. The liquid‐phase polymer‐based retention (LPR) technique was used. This technique consists of retention of arsenate anions by the quaternary ammonium salt of a water‐soluble polymer in a filtration membrane cell. It was shown that the polymers could bind H2AsO species from an aqueous solution more selectively at pHs of 6 and 8, than at a pH of 4. An increase in the polymer concentration was associated with increased retention capacity but not linearly. At the highest concentration the influence of pH was better observed. Investigation of copolymers showed the concerted action of polycations and polyanions on the ability to retain arsenic. At the lowest pH, the role of ionic strength of the media had a remarkable effect on the retention ability, independently of copolymer composition. At a pH of 6 a copolymer polycation/polyanion composition of 2 : 1 had the highest selective effect. At a pH of 8, a nonequimolar copolymer composition showed the same efficiency for the retention of arsenate species. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2677–2684, 2006
Properties of polyurethane coatings containing additives of phenolic compounds
Authors: Yokoyama Naoki
Published: August 2006

The properties of polyurethane containing five kinds of model phenolic additives were investigated. The IR spectra of polyurethane containing phenolic additives indicated that the phenolic additives reacted with isocyanate groups in a polyisocyanate compound. For an index of anticorrosion, the tensile adhesion strength was measured for polyurethane coatings with phenolic additives on steel plates treated with the salt‐water spraying test for 3000 h. It was found that there was a relationship between the tensile adhesion strength of polyurethane and the density. We considered the reason to be that the increase in density (i.e., a reduction in free volume) should provide a route to reduce salt‐water access to an adhesive bond. The increase in density was explained by the term antiplasticizers, which means that the phenolic additives reduce the free volume that is available for molecular motion in the stiff chain of polyurethane. In the polyurethanes with every phenolic additive, the elongation was increased, the moduli were decreased, the storage modulus was decreased, and the coefficient of thermal expansion was increased. These phenomena are the characteristics of plasticizers. Thus, the phenolic additives have both the character of antiplasticizers and plasticizers, but the polyurethane with phenolic additives had more characteristics of plasticizers than those of antiplasticizers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2099–2106, 2006
Polyaniline/FE3O4 magnetic nanocomposite prepared by ultrasonic irradiation
Authors: Qiu Guihua , Wang Qi , Nie Min
Published: August 2006

Ultrasonic irradiation is employed to assist the chemical oxidative polymerization of aniline in the presence of Fe3O4 nanoparticles in order to prepare a polyaniline (PANI)/Fe3O4 magnetic nanocomposite. In the chemical oxidative polymerization of aniline in the initially neutral medium, the optimum molar ratio of the oxidant ammonium persulfate to the monomer aniline is 2 : 1. The prepared PANI is in the emeraldine form and is doped by sulfate anions. Fe3O4 particles are encapsulated by PANI and dispersed well in PANI. Fe3O4 increases the doping level and decreases the crystallinity of PANI. The PANI/Fe3O4 nanocomposite possesses conductivity and magnetic properties. Increasing the Fe3O4 content increases the magnetization of the PANI/Fe3O4 composite but decreases its conductivity. © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2107–2111, 2006
Low temperature solid‐state extrusion of recycled poly(ethylene terephthalate) bottle scraps
Authors: Guo Weihong , Tang Xianwen , Yin Guorong , Gao Yuanji , Wu Chifei
Published: August 2006

The processing of poly(ethylene terephthalate) (PET) involves thermal and hydrolytic degradation of the polymer chain, which reduces not only the intrinsic viscosity and molecular weight, but also the mechanical properties of recycled materials. A novel PET/bisphenol A polycarbonate/styrene–ethylene–butylene–styrene alloy based on recycled PET scraps is prepared by low temperature solid‐state extrusion. Hydrolysis and thermal degradation of PET can be greatly reduced by low temperature solid‐state extrusion because the extrusion temperature is between the glass‐transition temperature and cold‐crystallization temperature of PET. Modification of recycled PET by low temperature solid‐state extrusion is an interesting method; it not only provides an easy method to recycle PET scraps by blend processing, but it can also form novel structures such as orientation, crystallization, and networks in the alloy. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2692–2699, 2006