bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of styrene–ethylene–butylene–styrene based additives on the mechanical properties of rice hull/polypropylene composites
Authors: Kuboki T. , Lee Y.H. , Park C.B. , Sain M.
Published: May 2007

The purpose of this study was to improve the mechanical properties (such as tensile, flexural, and impact strength) of rice hull/polypropylene composites, with the use of styrene–ethylene–butylene–styrene copolymer (SEBS) and maleated styrene–ethylene–butylene–styrene copolymer (SEBS‐MA). The results suggested that both types of additives increased the impact strength of the composites significantly as their contents increased. However, only SEBS‐MA improved the tensile and flexural strength of the composites. The results also indicated that the composites with SEBS‐MA consistently showed better mechanical properties than the SEBS counterparts for all the contents. POLYM. ENG. SCI., 47:1148–1155, 2007. © 2007 Society of Plastics Engineers
Rheological, thermal, and morphological properties of blends based on poly(propylene), ethylene propylene rubber, and ethylene‐1‐octene copolymer that could result from end of life vehicles: Effect of maleic anhydride grafted poly(propylene)
Authors: Jaziri Mohamed , Mnif Nizar , Massardier‐Nageotte Valérie , Perier‐Camby Hervé
Published: May 2007

The objective of this work is to study the properties of blends that could result from the recycling of end‐of‐life vehicles (ELV). While ethylene propylene rubber (EPR) and ethylene propylene diene monomer (EPDM) have been used extensively as elastomeric additives in poly(propylene) (PP), they can be substituted by ethylene‐1‐octene copolymer (EOC). As a consequence, the matter resulting from the sorting of ELV might be more complex and made of PP, EPR, and EOC. The effect of incorporating EOC [that is a polyethylene elastomer (PEE)] and maleic anhydride grafted polypropylene (PP‐g‐MAH) on the rheological, thermal, and morphological properties of PP/EPR blends has been investigated. Blends of various compositions (with and without compatibilizer) were prepared using a corotating twin‐screw extruder. The results were compared to the ones presented by a commercial (PP/EPR) blend. The EPR phase is dispersed in the form of spherical particles in (PP/EPR). The EOC phase is dispersed in the form of aggregated particles. Dynamic viscoelastic and differential scanning calorimetry properties of (PP/EPR)/EOC blends shows the incompatibility of the components even in presence of PP‐g‐MAH copolymer. POLYM. ENG. SCI., 47:1009–1015, 2007. © 2007 Society of Plastics Engineers
Highly transparent polypropylene cast films: Relationships between optical properties, additives, and surface structure
Authors: Resch Katharina , Wallner Gernot M. , Teichert Christian , Gahleitner Markus
Published: May 2007

Polypropylene homopolymer and ethylene/propylene‐random‐copolymer cast films formulated with various amounts of slip and antiblocking aids as well as acid scavengers and produced under different processing conditions were characterized with respect to surface structure and optical properties. The topographical analysis was done by atomic force microscopy (AFM). Optical properties were determined using a hazemeter and an UV/Vis/NIR spectrophotometer. AFM height images revealed a significant influence of processing conditions on the development of surface structures. Besides the occurrence of scratches displaying the replica of the metallic chill roll, particularly characteristic eight‐shaped superlamellar crystalline features were affected by the cooling conditions. Relationships between surface enrichment of additives and vertical and lateral roughness parameters were established. In general, film types formulated without additives exhibit better optical properties. For film types formulated with polymer‐processing aids, the diffuse‐scattering power is reduced by low molecular weight, high amounts of acid scavenger aid, and antiblocking agents with low porosity. A separation of haze into its bulk and surface components indicated that total haze is dominated by surface haze. The comparison of haze and the vertical roughness parameters exhibited a tendency of a linear correlation. POLYM. ENG. SCI., 47:1021–1032, 2007. © 2007 Society of Plastics Engineers
Quantification of the melting process in a co‐rotating twin‐screw extruder: A hybrid modeling approach
Authors: Garge S.C. , Wetzel M.D. , Ogunnaike B.A.
Published: May 2007

In extrusion processes, melting strongly influences the development of product end‐use properties such as tensile strength. For effective monitoring and control of these properties, it is essential to describe the melting process quantitatively. Obtaining a high‐fidelity quantitative description of the melting process, however, remains a challenging problem. This article proposes and employs a hybrid (physical/empirical) modeling approach to model the melting process. The recently developed “pulse perturbation technique” is used to generate the input/output data, while the model structure is determined from physical considerations. Each parameter of the identified model can therefore be associated with a distinct melting mechanism, thus providing valuable quantitative insight into the melting process. Based on the melting data presented in Wetzel et al. [1], the model is used to analyze the effect of extruder operating conditions on the melting of semicrystalline, amorphous, and rubbery polymers. Pulse experiments are conducted on an example reactive extrusion process and a quantitative relationship between the model parameters and end‐use properties is developed. Such a quantitative relationship can be used for fast predictions of infrequently measured end‐use properties and therefore has potential applications in monitoring and control of product characteristics in extrusion processes. POLYM. ENG. SCI., 47:1040–1051, 2007. © 2007 Society of Plastics Engineers
Failure characterization of polypropylene block copolymer welded joints
Authors: Fasce Laura , Cisilino Adrián , Frontini Patricia , Marczis Balazs , Czigany Tibor
Published: May 2007

The failure behavior of polypropylene block copolymer double‐V welded joints was investigated. Joints were prepared using the hot‐gas welding technique at varying gas temperatures in the range of 230–260°C. Uniaxial tensile tests, fracture mechanics experiments, several microscopy techniques, and complementary FEM analysis were carried out to assess the quality of filler rods and welding interfaces. The developed interfaces were weaker than the parent material as a consequence of polymer chains segregation during the welding process. The hot‐gas temperature had a marked effect on the failure behavior of the welds. The highest interface toughness was attained at the highest gas welding temperature used at which, polymer chains were able to quickly diffuse into the parent material enlarging the distance of penetration and hence the micro‐deformation capability of the joint. POLYM. ENG. SCI., 47:1062–1069, 2007. © 2007 Society of Plastics Engineers
Cell structure and dynamic properties of injection molded polypropylene foams
Authors: Guo Ming‐Cheng , Heuzey Marie‐Claude , Carreau Pierre J.
Published: May 2007

The cell structure and properties of branched and linear polypropylene (PP) foams containing organically modified nanoclay and maleic anhydride grafted polypropylene (PPMA) have been thoroughly investigated. X‐ray diffraction (XRD) and melt rheometry were used to identify the structure and linear viscoelastic properties of the nanocomposites, as well as the effectiveness of two different compatibilizers. These nanocomposites were used in injection molding to investigate their foamability and the influence of experimental conditions such as chemical foaming agent concentration, shot size, back pressure, injection speed, as well as melt temperature and different injection methods on the resulting cell structure of the foams. Quite different results were obtained with the linear and the branched PP. While the foamability of the branched PP was intrinsically good, that of the linear one could largely be improved by modifying its rheological properties and favoring nucleation through the addition of nanoclay. The effect of cell structure on the dynamic mechanical properties of the foams was also investigated using dynamic mechanical analysis (DMA). POLYM. ENG. SCI., 47:1070–1081, 2007. © 2007 Society of Plastics Engineers
Photopolymerization and initiating mechanism of Michael addition oligomers without photoinitiator
Authors: Zhang Xiahong , Yang Jianwen , Zeng Zhaohua , Wu Yuanwei , Huang Liang , Chen Yonglie , Wang Haihua
Published: May 2007

A series of acrylic oligomer which can undergo self‐initiation under UV irradiation were synthesized by Michael addition of acetylacetone (acac) with multi‐functional acrylates using diazabicycloundecene as catalyst. GC‐MS and proton NMR were employed to study the photolysis mechanism of model molecule which was prepared from acac and ethyl acrylate. The β‐diketone moiety attached to a fully substituted carbon atom was photoscissile and prone to produce alkyl free radicals by losing acetyl free radical. Polymerization of the acrylated β‐diketone‐containing oligomers can be thus efficiently triggered regardless of solely irradiated under UV light or blended with pure trimethylolpropane triacrylate. As determined with photo‐DSC, the acrylated β‐diketone‐containing oligomers photopolymerized more slowly than the traditional system of trimethylolpropane triacrylate containing Darocur 1173 at the early stage, but reached a higher final conversion. The rheology measurement showed that the synthesized acrylated β‐diketone‐containing oligomers exhibited shear thinning property. POLYM. ENG. SCI., 47:1082–1090, 2007. © 2007 Society of Plastics Engineers
Reclaiming of ground rubber tire by a novel reclaiming agent. I. virgin natural rubber/reclaimed GRT vulcanizates
Authors: De Debapriya , De Debasish , Singharoy G.M.
Published: May 2007

Mechanochemically devulcanized ground rubber tire (GRT) was (re)vulcanized in compositions with virgin natural rubber (NR). The NR/GRT (re)vulcanizates with GRT content from 20 to 60 wt% have been prepared and studied. Reclaiming of GRT was successfully carried out by tetra methyl thiuram disulfide (TMTD) in presence of spindle oil at around ambient temperature. The cure characteristics and mechanical properties of the virgin NR/reclaim GRT blend were studied. The optimum cure time decreases but scorch time remain unaltered with increasing reclaim rubber content in the blend. Effect of carbon black was studied in NR/RR (80/20) blend. Ageing characteristics of different NR/RR blends were evaluated. Scanning electron microscopy (SEM) studies further indicate the coherency and homogeneity in the NR/RR vulcanizate. The dynamic mechanical properties and swelling behavior of NR/RR blend vulcanizates were examined. The elastic and storage modulus of the NR/RR vulcanizates become improve with increasing reclaim rubber content. Electrical properties of NR/RR vulcanizates were also studied. POLYM. ENG. SCI., 47:1091–1100, 2007. © 2007 Society of Plastics Engineers
Mechanical and oxygen barrier properties of organoclay‐polyethylene nanocomposite films
Authors: Zhong Yang , Janes Dustin , Zheng Yong , Hetzer Max , De Kee Daniel
Published: May 2007

An organically modified montmorillonite was compounded with ethylene vinyl acetate copolymer (EVA), low density polyethylene (LDPE), and high density polyethylene (HDPE) in a twin‐screw extruder. The resulting organoclay‐polyethylene nanocomposites were then blown into films. Tensile properties and oxygen permeability of these nanocomposite films were investigated to understand the effects of organoclay on different types of polyethylene. It was found that the clay enhancing effects are function of the matrix. The mechanical and oxygen barrier properties of clay/EVA systems increased with clay loading. Both the tensile modulus and oxygen barrier of EVA doubled at 5 wt% clay. Maleic anhydride grafted polyethylene (MAPE) usually is used as a compatibilizer for LDPE and HDPE‐based nanocomposites. However, the MAPEs were found to weaken the oxygen barrier of the PEs, especially for HDPE. This is believed to be a result of less compactness caused by the large side groups and the increase in polarity of the MAPEs. Incorporating 5 wt% clay improves the oxygen barrier by 30% and the tensile modulus by 37% for the LDPE/MAPE system. Incorporation of clay does not enhance the properties of the HDPE‐based systems, likely due to large domain structure and poor bonding. Halpin–Tsai equation and the tortuous path equation were used to model the tensile modulus and oxygen permeability of the clay/EVA nanocomposite films. POLYM. ENG. SCI., 47:1101–1107, 2007. © 2007 Society of Plastics Engineers
Digital image processing method for measuring the residence time distribution in a plasticating extruder
Authors: Bi Chao , Jiang Bo , Li Ao
Published: May 2007

In the present work, a digital image processing (DIP) method was developed to measure the residence time distribution (RTD) in a plasticating extruder. The DIP method is off‐line, but it consumes less time and yields more data than the traditional off‐line ones, and it avoids the expensive probes and data acquisition systems that are necessary in the on‐line and in‐line measurements. The correctness of the DIP method was validated by a comparative experiment using silica powder as the tracer. A locally made Buss Kneader equipped with a gear pump system was used herein. The effects of the operating conditions on the RTD in this equipment were also studied. Furthermore, the relationship between the mean residence time and the operating conditions was analyzed. POLYM. ENG. SCI., 47:1108–1113, 2007. © 2007 Society of Plastics Engineers
Direct analysis of the extracellular proteome from two strains of Helicobacter pylori
Authors: Smith Todd G. , Lim Jae‐Min , Weinberg Michael V. , Wells Lance , Hoover Timothy R.
Published: May 2007

Helicobacter pylori extracellular proteins are of interest because of possible roles in pathogenesis, host recognition, and vaccine development. We utilized a unique approach by growing two strains (including one nonsequenced strain) in a defined serum‐free medium and directly analyzing the proteins present in the culture supernatants by LC‐MS/MS. Over 125 proteins were identified in the extracellular proteomes of two H. pylori strains. Forty‐five of these proteins were enriched in the extracellular fraction when compared to soluble cell‐associated protein samples. Our analysis confirmed and expanded on the previously reported H. pylori extracellular proteome. Extracellular proteins of interest identified here included cag pathogenicity island protein Cag24 (CagD); proteases HP0657 and HP1012; a polysaccharide deacetylase, HP0310, possibly involved in the hydrolysis of acetyl groups from host N‐acetylglucosamine residues or from residues on the cell surface; and HP0953, an uncharacterized protein that appears to be restricted to Helicobacter species that colonize the gastric mucosa. In addition, our analysis found eight previously unidentified outer membrane proteins and two lipoproteins that could be important cell surface proteins.
Proteomics of European beech (Fagus sylvaticaL.) seed dormancy breaking: Influence of abscisic and gibberellic acids
Authors: Pawłowski Tomasz Andrzej
Published: May 2007

A proteomic approach was used to analyze mechanisms of dormancy breaking in beech (Fagus sylvaticaL.) seeds and the participation of abscisic and gibberellic acids (ABA and GA) in this process. After imbibition in water, ABA, or GA3solutions, beechnuts were subjected to cold stratification, which breaks their dormancy. ABA delayed, whereas GA3promoted seed dormancy breaking. Proteome maps for water, ABA, and GA3were established, which displayed 1544 silver‐stained spots. A total of 74 spots, showing significant changes in volume, were identified by MS. Of these, 18, 45, and 16 spots were identified as water‐, ABA‐, and GA3‐responsive, respectively (five were regulated by both hormones). The classification of proteins showed that most of the proteins associated with dormancy breaking in water are involved in energy metabolism and protein destination. Most of the ABA‐responsive proteins are involved in protein destination, energy metabolism, and development. Most of the GA3‐responsive proteins are involved in energy metabolism (many more than for ABA and water) and plant defense. We conclude that the mechanism of seed dormancy breaking involves the proteins of many processes, beginning with hormone signal initiation, through signal transduction, transcription, protein synthesis, energy metabolism, storage materials, and ending with the cell cycle.
Immunodominant Francisella tularensis antigens identified using proteome microarray. ©Crown Copyright 2007 Dstl
Authors: Eyles Jim E. , Unal Berkay , Hartley Margaret Gill , Newstead Sarah L. , Flick‐Smith Helen , Prior Joann L. , Oyston Petra C. F. , Randall Arlo , Mu Yunxiang , Hirst Siddiqua , Molina Douglas M. , Davies D. Huw , Milne Tim , Griffin Kate F. , Baldi Pierre , Titball Rick W. , Felgner Philip L.
Published: May 2007

Stimulation of protective immune responses against intracellular pathogens is difficult to achieve using non‐replicating vaccines. BALB/c mice immunized by intramuscular injection with killed Francisella tularensis (live vaccine strain) adjuvanted with preformed immune stimulating complexes admixed with CpG, were protected when systemically challenged with a highly virulent strain of F. tularensis (Schu S4). Serum from immunized mice was used to probe a whole proteome microarray in order to identify immunodominant antigens. Eleven out of the top 12 immunodominant antigens have been previously described as immunoreactive in F. tularensis. However, 31 previously unreported immunoreactive antigens were revealed using this approach. Twenty four (50%) of the ORFs on the immunodominant hit list belonged to the category of surface or membrane associated proteins compared to only 22% of the entire proteome. There were eight hypothetical protein hits and eight hits from proteins associated with different aspects of metabolism. The chip also allowed us to readily determine the IgG subclass bias, towards individual or multiple antigens, in protected and unprotected animals. These data give insight into the protective immune response and have potentially important implications for the rational design of non‐living vaccines for tularemia and other intracellular pathogens.
Proteome and cytoskeleton responses in osteosarcoma cells with reduced OXPHOS activity
Authors: Annunen‐Rasila Johanna , Ohlmeier Steffen , Tuokko Hanna , Veijola Johanna , Majamaa Kari
Published: May 2007

We have recently shown disorganization of the vimentin network in cultured cells deficient in oxidative phosphorylation (OXPHOS). We describe here the cellular responses to OXPHOS deficiency in osteosarcoma cells upon complex I (CI) and complex IV (CIV) inhibition, and upon the lack of mitochondrial DNA (ρ0 cells). We examined the cytoskeletal organization and the distribution of mitochondria and analysed total proteome by 2‐DE and vimentin expression by ELISA. Upon CIV inhibition and in ρ0 cells, the vimentin network had collapsed around the nucleus and formed thick bundles. The mitochondria formed a perinuclear crescent upon CIV inhibition, whereas they accumulated around the nucleus in the ρ0 cells, where the amount of vimentin was increased. Analysis of the total proteome revealed that a lack of mitochondrial DNA or inhibition of CI or CIV led to changes in the expression of cytoskeletal and cytoskeleton‐associated proteins and proteins involved in apoptosis, OXPHOS, glycolysis, the tricarboxylic acid cycle, and oxidative stress responses. Our findings suggest that a deficiency in the energy converting system and oxidative stress can lead to cytoskeletal changes.
Concordance between patients' desired and actual decision‐making roles in breast cancer care
Authors: Vogel Barbara A. , Helmes Almut W. , Hasenburg Annette
Published: May 2007

This study explored breast cancer patients' preferences and experiences for participation in treatment decision making as well as the concordance between patients' actual and desired decision making. The interplay between depression, anxiety and decision‐making preferences was also examined.

A consecutive sample of primary breast cancer patients was recruited within a week of either surgery or the beginning of neo‐adjuvant chemotherapy in two breast cancer centres in Germany. Women were asked to complete a self‐explanatory questionnaire.

Most patients (40.2%) of the 137 participants preferred the physician to make the treatment decision. A total of 63.4% were able to fulfil their preferred decision‐making role. Breast cancer patients who wanted the physician to make the decision and patients who wanted to make the decision on their own were more likely to have their preferences met than patients who wished to share the decision (p<0.01). Availability of treatment choice and the level of depression influenced the preferred decision‐making preference.

Limited concordance between desired and actual decision making of patients with collaborative decision‐making preferences suggests the need for better communication and physician training on shared decision making. Copyright © 2007 John Wiley & Sons, Ltd.
Husbands' perceptions of wives' adjustment to breast cancer: the impact on wives' mood
Authors: Romero Catherine , Lindsay Julie E. , Dalton William T. , Nelson David V. , Friedman Lois C.
Published: May 2007

Married women's adjustment to breast cancer is positively influenced by their husbands' emotional support and by both spouses' active coping strategies. However, little is known about how women's adjustment is related to their husbands' perceptions of their psychosocial impairment. The current study examined the relationships among wives' coping strategies, the extent of congruence between wives' and husbands' perceptions of wives' adjustment, and wives' mood disturbance in 45 women with Stage I or II breast cancer and their husbands. Mediational analyses demonstrated that discrepancies between husbands' perceptions of wives' adjustment and wives' perceptions of their own adjustment mediated the relationship between wives' use of avoidant coping strategies and wives' mood disturbance. The findings suggest that husbands' over‐ or under‐estimation of wives' adjustment may have a negative impact on wives' mood. Implications for future research are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Sampling Errors in Particle Size Analysis?
Authors: Merkus Henk G.
Published: May 2007

Sampling errors are highly underestimated in particle size analysis of more or less free‐flowing powders. This is wrong. For, such errors often dominate in the results. They consist of two components. The first component is the fundamental error, related to the discrete nature of particulate materials. It determines the minimum amount of sample that has to be taken into account to reach a required precision. This fundamental error can be estimated from the number of particles. The second component is the segregation error. It relates to the segregation that occurs in the batch of material to be sampled or during the sampling process. This segregation error can only be estimated from the analysis results of multiple samples. Guidance on the estimation of both types of sampling errors in relation to the minimum mass and minimum number of primary samples taken from a product lot will be given in this paper.
Insecticide resistance in disease vectors of public health importance
Authors: Nauen Ralf
Published: May 2007

Vector‐borne diseases are a global problem—a trend that may only increase if global temperature rises and demographic trends continue–and their economic and social impact are enormous. Insecticides play a vital role in the fight against these diseases by controlling the vectors themselves in order to improve public health; however, resistance to commonly used insecticides is on the rise. This perspective outlines the major classes of disease vector control agents and the mechanisms of resistance that have evolved, arguing that effective resistance management strategies must carefully monitor resistance in field populations and use combinations of the limited modes of action available to best effect. Moreover, the development of novel insecticide classes for control of adult mosquitoes and other vectors becomes increasingly important. Copyright © 2007 Society of Chemical Industry
PREDICT‐1 (CNA106030): the first powered, prospective trial of pharmacogenetic screening to reduce drug adverse events
Authors: Hughes Sara , Hughes Arlene , Brothers Cindy , Spreen William , Thorborn Daren
Published: May 2007

Pharmacogenetics (PGx) – the study of DNA variation in the human genome and the way this impacts the efficacy and safety of medicines – is becoming an increasingly important research tool as physicians, patients, regulatory authorities and payers look for innovative ways to improve the risk:benefit ratio of medicines. While scientific knowledge about PGx is rapidly increasing, implementation of PGx findings to patient care has yet to be fully achieved. One area where significant progress has been made is in the identification of PGx markers associated with variable response to antiretroviral medicines. For example, the major histocompatibility complex HLA‐B*5701 allele has been associated with hypersensitivity to abacavir (ABC) by several independent researchers. While PGx associations have been identified largely through retrospective examination, the clinical utility of these PGx markers in patient care has not been prospectively determined in a randomized study. This paper outlines the design of a study to evaluate the utility of prospective screening for HLA‐B*5701 to reduce the incidence of ABC hypersensitivity in an ABC‐naïve population of HIV‐infected subjects. This represents the first fully powered, randomized, blinded, prospective study to determine the clinical utility of PGx screening to reduce drug‐associated adverse events in any patient population. This type of trial design may have utility for other important medicines which have treatment‐limiting side effects. Copyright © 2007 John Wiley & Sons, Ltd.
The medieval physician Avicenna used an herbal calcium channel blocker, Taxus baccata L.
Authors: Tekol Yalcin
Published: May 2007

Calcium channel blockers are drugs which are important for current medical therapy. The first examples of synthetic congeners of this class of drugs appear around at the beginning of the 1960s. Review of the current and historical literature shows that Avicenna (Ibn Sina) (980–1037) had used the herbal drug ‘Zarnab’ (Taxus baccata L.) as a cardiac remedy. The leaves of T. baccata contain an alkaloid mixture (taxines). It was recently demonstrated that this drug possessed calcium channel blocking activity. So, it is evident that Avicenna used a drug with calcium channel blocking activity much earlier than the arrival of synthetic drugs belonging to the same pharmacological group. Copyright © 2007 John Wiley & Sons, Ltd.
The evidence based wound healing activity of Lawsonia inermis Linn.
Authors: Nayak B. Shivananda , Isitor Godwin , Davis E. M. , Pillai G. K.
Published: May 2007

The ethanol extract of Lawsonia inermis (200 mg/kg/day) was used to evaluate the wound healing activity on rats using excision, incision and dead space wound models. The animals were divided into three groups of six each in the excision model and two groups of six each in the incision model and dead space models. The topical application was made in the case of excision wound model, whereas, oral treatment was done with incision and dead space wound models. The following differences were noted in the group of experimental animals which were treated with an extract of L. inermis when compared with the control and reference standard animals: a high rate of wound contraction (p < 0.001), a decrease in the period of epithelialization (p < 0.001), high skin breaking strength (p < 0.001), a significant increase in the granulation tissue weight (p < 0.001) and hydroxyproline content (p < 0.05). The extract‐treated animals showed 71% reduction in the wound area when compared with controls which was 58%. Histological studies of the tissue obtained on day 10 from the extract‐treated group showed increased well organized bands of collagen, more fibroblasts and few inflammatory cells when compared with the controls which showed inflammatory cells, scanty collagen fibres and fibroblasts. Enhanced wound contraction, increased skin breaking strength, hydroxyproline and histological findings suggest the use of L. inermis in the management of wound healing. Copyright © 2007 John Wiley & Sons, Ltd.
Optimizing the performance of a repairable system under a maintenance and repair contract
Authors: Lugtigheid Diederik , Jardine Andrew K. S. , Jiang Xiaoyue
Published: May 2007

In this article a number of maintenance models for finite horizons are reviewed. These methods have not been applied as frequently as their infinite horizon counterparts, and yet are very much applicable to systems under maintenance and repair contracts. The emphasis in this paper is on repairable systems under maintenance and repair contracts, where the decision has to be made whether and when to repair or replace the system. Based on a case study, a new finite horizon model will be constructed and new approaches to analyze and improve repair/replacement decisions under a finite horizon introduced. Finally, the meaning of ‘risk’ and ‘criticality’ in the context of maintenance contracts will be discussed and quantified. Copyright © 2007 John Wiley & Sons, Ltd.
Fish zonation and indicator species for the evaluation of the ecological status of rivers: example of the Loire basin (France)
Authors: Lasne Emilien , Bergerot Benjamin , Lek Sovan , Laffaille Pascal
Published: May 2007

In the context of river alteration, ecologists are asked to develop tools for the assessment of river integrity. Fish are known to be good bioindicators of the ecological condition of rivers. The Loire basin (France) is often considered as relatively little impacted compared to most other large European systems. But curiously, no study clearly addressed the question of fish assemblages patterns in this system in order to assess this status. Thus, we studied fish assemblages along the river network in the Loire basin using self‐organizing maps (SOMs) and we built a fish typology. Four basic assemblages were described and indicator species were identified. These assemblages varied in terms of individual species patterns as well as in terms of flow preference guilds and species richness. A discriminant analysis carried out on environmental variables revealed that they could be mainly determined by the slope, temperature and depth. Finally, fish assemblages were arrayed along a longitudinal gradient and roughly fitted the theoretical zonation expected in European rivers with the succession of brown trout (Salmo trutta fario), grayling (Thymallus thymallus), barbel (Barbus barbus) and bream (Abramis brama) zones in a downstream direction. Such patterns are still rarely observed in large European systems. However, the fish assemblage characteristic of the bream zone occurred more frequently than predicted on the basis of environmental variables. Such deviations between field data and theory suggest lotic‐to‐lentic shifts probably due to anthropogenic disturbances, especially in the grayling and barbel zones. In these river sectors, eurytopic and limnophilic species tend to replace rheophilic ones. Finally, the method used in this study to investigate fish patterns may be helpful to detect disturbances and may serve as a tool for the establishment of management plans. Copyright © 2007 John Wiley & Sons, Ltd.
Pragmatic integrated scheduling for clustered VLIW architectures
Authors: Nagpal Rahul , Srikant Y. N.
Published: May 2007

Clustered architecture processors are preferred for embedded systems because centralized register file architectures scale poorly in terms of clock rate, chip area, and power consumption. Scheduling for clustered architectures involves spatial concerns (where to schedule) as well as temporal concerns (when to schedule). Various clustered VLIW configurations, connectivity types, and inter‐cluster communication models present different performance trade‐offs to a scheduler. The scheduler is responsible for resolving the conflicting requirements of exploiting the parallelism offered by the hardware and limiting the communication among clusters to achieve better performance. In this paper, we describe our experience with developing a pragmatic scheme and also a generic graph‐matching‐based framework for cluster scheduling based on a generic and realistic clustered machine model. The proposed scheme effectively utilizes the exact knowledge of available communication slots, functional units, and load on different clusters as well as future resource and communication requirements known only at schedule time. The proposed graph‐matching‐based framework for cluster scheduling resolves the phase‐ordering and fixed‐ordering problem associated with earlier schemes for scheduling clustered VLIW architectures. The experimental evaluation in the context of a state‐of‐art commercial clustered architecture (using real‐world benchmark programs) reveals a significant performance improvement over the earlier proposals, which were mostly evaluated using compiled simulation of hypothetical clustered architectures. Our results clearly highlight the importance of considering the peculiarities of commercial clustered architectures and the hard‐nosed performance measurement. Copyright © 2007 John Wiley & Sons, Ltd.
A personalized search engine based on Web‐snippet hierarchical clustering
Authors: Ferragina P. , Gulli A.
Published: May 2007

We propose a (meta‐)search engine, called SnakeT (SNippet Aggregation for Knowledge ExtracTion), which queries more than 18 commodity search engines and offers two complementary views on their returned results. One is the classical flat‐ranked list, the other consists of a hierarchical organization of these results into folders created on‐the‐fly at query time and labeled with intelligible sentences that capture the themes of the results contained in them. Users can browse this hierarchy with various goals: knowledge extraction, query refinement and personalization of search results. In this novel form of personalization, the user is requested to interact with the hierarchy by selecting the folders whose labels (themes) best fit her query needs. SnakeT then personalizes on‐the‐fly the original ranked list by filtering out those results that do not belong to the selected folders. Consequently, this form of personalization is carried out by the users themselves and thus results fully adaptive, privacy preserving, scalable and non‐intrusive for the underlying search engines. We have extensively tested SnakeT and compared it against the best available Web‐snippet clustering engines. SnakeT is efficient and effective, and shows that a mutual reinforcement relationship between ranking and Web‐snippet clustering does exist. In fact, the better the ranking of the underlying search engines, the more relevant the results from which SnakeT distills the hierarchy of labeled folders, and hence the more useful this hierarchy is to the user. Vice versa, the more intelligible the folder hierarchy, the more effective the personalization offered by SnakeT on the ranking of the query results. Copyright © 2007 John Wiley & Sons, Ltd.
Impact of altered loading conditions on ventricular performance in fetuses with congenital cystic adenomatoid malformation and twin–twin transfusion syndrome
Authors: Szwast A. , Tian Z. , McCann M. , Donaghue D. , Bebbington M. , Johnson M. , Wilson R. D. , Rychik J.
Published: May 2007

Objectives

In the fetus with a structurally normal heart, two conditions—giant chest mass, such as congenital cystic adenomatoid malformation (CCAM), and twin–twin transfusion syndrome (TTTS)—alter ventricular loading conditions and may result in cardiovascular compromise. The aim of this study was to elucidate the mechanism of cardiovascular dysfunction by comparing geometry‐independent, Doppler flow‐derived measures of ventricular performance in fetuses with altered loading conditions vs. those in normal fetuses.

Methods

Doppler flow‐derived measures of myocardial performance index (MPI) as described by Tei, ventricular ejection force as described by Isaaz, and combined cardiac output (CCO) were obtained by echocardiography in fetuses with a normal cardiovascular system (n = 76) or CCAM (n = 36) and fetal partners with TTTS (n = 22).

Results

In the CCAM group, systolic performance as evidenced by the ejection forces was preserved, right ventricular (RV) MPI was increased and CCO diminished, suggesting diastolic dysfunction and poor filling secondary to cardiac compression and a tamponade effect. In TTTS, recipient twins exhibited greater left ventricular (LV) ejection forces and higher CCO than donor twins, and had abnormal RV and LV MPI, reflecting increased preload, preserved left systolic performance, but diastolic dysfunction. Donor twins had diminished ejection forces and CCO in comparison with normal controls and recipient partners, reflecting hypovolemia.

Conclusions

In both CCAM and recipient twins of the TTTS, diastolic dysfunction plays a significant role in the pathophysiology of each disorder and precedes changes in systolic performance. Measures of ventricular performance can help elucidate poorly understood mechanisms of cardiovascular compromise in the developing fetus. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
X‐ray fluorescence analysis with sample excitation using radiation from a secondary target
Authors: Vasin M. G. , Ignatyev Yu. V. , Lakhtikov A. E. , Morovov A. P. , Nazarov V. V. , Trakhtenberg L. I.
Published: May 2007

This paper presents a scheme of an x‐ray spectrometer with exchangeable secondary targets and investigation of its characteristics. A high‐voltage power source with a voltage up to 75 kV and x‐ray tubes with power up to 2.5 kW were used in the spectrometer to generate the primary x‐ray radiation. The exchangeable secondary targets made it possible to get monochromatic radiation with a rather high degree of the spectral contrast. The use of tubes with different anodes materials (chromium, tungsten and rhodium) and different secondary targets provides efficient performance for the analysis of a range of concentrations of elements with atomic numbers 13 < Z < 92. In this case, it was possible to optimize the sample analysis for definite groups of elements, reaching detection limits (DL) of 10−6 g/g in aqueous solutions. According to the sensitivity (DL), this device can act as a spectrometer with total external reflection of the primary beam (TXRF spectrometer). However, its design is simpler, it has better optical efficiency, its adjustment is simple and convenient and it has a high operating efficiency. Besides, the design of the device makes it possible to perform simultaneously, if necessary, x‐ray fluorescence and x‐ray absorption analyses of a sample. Examples of the application of the device for the determination of heavy‐metal content in the aqueous solutions and measurement of thickness of films are presented in this paper. Copyright © 2007 John Wiley & Sons, Ltd.
Direct in vivo access to potential gene targets of the RPD3 histone deactylase using fitness‐based interferential genetics
Authors: Daniel Jacques
Published: May 2007

Using the fitness‐based interferential genetics (FIG) approach in yeast, potential in vivo gene targets of the Rpd3 histone deacetylase were selected. In agreement with previous studies using different methods, three genes were found to be involved in the translational machinery (MRPL27, FHL1 and RDN1). Moreover, other selected genes are linked to cell‐cycle control (CSE4, AMN1, VAC17 and GRR1). In addition to playing a crucial role in cell cycle progression to the S phase and participating in the G2–M transition, GRR1 has important functions related to nutrient import to the cell via the the derepression of hexose transporters and the induction of amino acid permeases. Consistent with this, FIG selection also retrieved: the PMA1 gene, encoding the plasma H+‐membrane ATPase; FOL2 and FOL3, involved in folic acid biosynthesis; and UBR2, which indirectly downregulates the proteasome genes. Finally, the other selected genes, ISU1, involved in the biosynthesis of the iron–sulphur cluster in mitochondria, and the less well functionally defined BSC5 and YBR270c, may participate in the cell's antioxidant and stress defence. The genes emerging from this FIG selection thus appear to be part of the downstream molecular mechanisms of the TOR signalling pathway, accounting for its effects on cell proliferation and longevity. From our results on gene expression under conditions of RPD3 overexpression, and by comparison with the available pharmacogenomics studies, it is proposed that FIG could be an invaluable approach for contributing to our understanding of complex cell regulatory systems. Copyright © 2007 John Wiley & Sons, Ltd.
Genetic characterization of commercial Saccharomyces cerevisiae isolates recovered from vineyard environments
Authors: Schuller Dorit , Pereira Leonor , Alves Hugo , Cambon Brigitte , Dequin Sylvie , Casal Margarida
Published: May 2007

One hundred isolates of the commercial Saccharomyces cerevisiae strain Zymaflore VL1 were recovered from spontaneous fermentations carried out with grapes collected from vineyards located close to wineries in the Vinho Verde wine region of Portugal. Isolates were differentiated based on their mitochondrial DNA restriction patterns and the evaluation of genetic polymorphisms was carried out by microsatellite analysis, interdelta sequence typing and pulsed‐field gel electrophoresis (PFGE). Genetic patterns were compared to those obtained for 30 isolates of the original commercialized Zymaflore VL1 strain. Among the 100 recovered isolates we found a high percentage of chromosomal size variations, most evident for the smaller chromosomes III and VI. Complete loss of heterozygosity was observed for two isolates that had also lost chromosomal heteromorphism; their growth and fermentative capacity in a synthetic must medium was also affected. A considerably higher number of variant patterns for interdelta sequence amplifications was obtained for grape‐derived strains compared to the original VL1 isolates. Our data show that the long‐term presence of strain VL1 in natural grapevine environments induced genetic changes that can be detected using different fingerprinting methods. The observed genetic changes may reflect adaptive mechanisms to changed environmental conditions that yeast cells encounter during their existence in nature. Copyright © 2007 John Wiley & Sons, Ltd.
Bemerkungen über die Methode von G. Duffing zur Integration von Differentialgleichungen
Authors: Pflanz Erwin
Published: May 2007

Bei der Duffingschen Lösungsmethode des Anfangswertproblems einer Diffgl. y′ (x) = f (x, y) mit y (x1) = y1 ergibt sich für eine Näherung Y von y (x) (x = x1 + h) eine Gleichung, in der auch Ableitungen von f auftreten. Diese und ähnliche Bestimmungsgleichungen für Näherungen Y (beliebig hoher Ordnung in h) von y lassen sich auch aus einer Verallgemeinerung der Taylorentwicklung für Funktionen einer Variablen entnehmen. Unter Voraussetzung der Monotonie einer gewissen Ableitung von f im betreffenden Intervall kann man den genauen Wert y (x1 + h) durch solche Näherungen Y in Schranken einschließen. Nach Übertragung der verallgemeinerten Taylorentwicklung auf Funktionen zweier Variablen werden damit zwei Verfahren (2. und 4. Ordnung) zur Lösung partieller Differentialgleichungen 1. Ordnung hergeleitet.
Fehlertrennung durch Wahrscheinlichkeitsbetrachtung
Authors: Meurers Joseph
Published: May 2007

Es wird eine Methode angegeben, die Fehler zweier voneinander verschiedener Meßweisen ein und derselben Größe zu trennen, wenn keine Anhaltspunkte dafür vorliegen, wie sich in der Praxis der beiden Meßarten die Fehler in den Meßresultaten auswirken. Durch eine Analyse der Wahrscheinlichkeiten in der Verteilung der Differenzen, welche die Messungen der betreffenden Größe nach beiden Methoden ergeben, über die zu messenden Argumente der beiden Meßweisen ist es möglich, diejenigen Wertintervalle für die zu messende Größe zu finden, in denen sich die eine bzw. die andere Meßmethode besonders durch ihre Fehler bemerkbar macht.
Über Bewegungen eines Schwingers unter dem Einfluß von Schwarz‐Weiß‐Regelungen I. Bewegungen eines Schwingers von einem Freiheitsgrad; Regelung mit Stellungszuordnung ohne Schaltverschiebungen
Authors: Flügge‐Lotz I. , Klotter K.
Published: May 2007

Sogenannte Schwarz‐Weiß‐Regelungen (auch Ja‐Nein‐Regelungen genannt) werden wegen ihres einfachen konstruktiven Aufbaus vielfach stetigen Regelungen vorgezogen. Wir beschränken uns in der vorliegenden Arbeit darauf, eine „ideale”︁ Regelung zu untersuchen, bei der das Stellglied dem Kommando, das durch die „Regelungsfunktion”︁ gegeben wird, sofort gehorcht. Die Schwingungseigenschaften des Stellgliedes und die Unvollkommenheiten im Gestänge, Fühler und Mischaggregat werden also zunächst vernachlässigt. Demnach erfolgt die Bewegung des Stellgliedes, solange auch für die Praxis die Abweichungen von der „idealen”︁ Regelung vernachlässigt werden können, im Takt der Bewegung des Hauptsystems. Das Ziel unserer Untersuchung ist, eine Übersicht über den Einfluß der System‐und Regelbeiwerte auf das zu erreichende Abklingverhalten zu gewinnen.
Pfeil‐Diagramme für Zylinderfunktionen
Authors: Emde Fritz
Published: May 2007

Diagramme für verschiedene Zylinderfunktionen desselben Arguments mit gleichen oder entgegengesetzt gleichen Parametern. Polardiagramm für eine Besselsche oder Hankelsche Funktion festen rein imaginären Arguments mit stetig veränderlichem Parameter. Umlaufs‐Diagramme.
Reduced Neuronal Innervation in the Distal End of the Proximal Esophageal Atretic Segment in Cases of Esophageal Atresia with Distal Tracheoesophageal Fistula
Authors: Boleken Mehmet , Demirbilek Savas , Kirimiloglu Hale , Kanmaz Turan , Yucesan Selcuk , Celbis Osman , Uzun Ibrahim
Published: May 2007

Background

Esophageal dysmotility is a common occurence after surgical repair of proximal esophageal atresia (EA) and distal tracheoesophageal fistula (TEF). The etiology of this motility disorder, however, remains controversial. Esophageal dysmotility also is present in isolated TEF or EA before surgery, suggesting a congenital cause. However, there is no information available in the literature with regard to the intramural nervous system of the human esophagus in EA‐TEF.

Patients and Methods

We examined the distal end of proximal esophageal atretic segment of neonates undergoing EA‐TEF repair for intrinsic neuronal innervation. Using specific antibodies, we studied neuronal markers of specimens from nine cases of EA‐TEF and 9 cases of normal esophagus by immunohistochemistry using neurofilament (NF), synaptophysin (SY), S100, and glial cell line‐derived neurotrophic factor (GDNF).

Results

In the atretic segment, specimens staining with hematoxylin and eosin showed that there were marked hypoganglionosis and immature ganglion cells in the myenteric plexus. GDNF immunoreactivity in the atretic esophagus were markedly reduced in both the muscular layer and myenteric plexus. SY and NF‐immunorective nerve fibers were distributed throughout the myenteric plexus of the normal esophagus, but the scarcity of these immunoreactive nerve fibers in the atretic esophagus was apparent. In contrast, the density of immunorective nerve fibers for S100 in the myenteric plexus and muscular layer was increased in the distal end of the atretic esophagus.

Conclusion

We concluded that the distribution of ganglion cells and some nerve fibers in the distal end of the atretic esophageal segment is deficient. Inadequate and abnormal neuronal innervation of the esophagus could be related to the esophageal dysmotility seen in EA. Because GDNF is a survival factor for central and peripheral neurons, defective expression of GDNF could have an important role in the defective and/or abnormal neuronal innervation of atretic esophageal segment.